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BestBestBestBestBest of of of the the the the the Best Best Best Best Best Best BestASHRAE Technology Awards
Radiant Heating and Cooling Systems | Energy-Efficient Makeup Air Units
Controller Sequences and Programming | Return Air Systems
MARCH 2015
J O U R N A LTHE MAGAZINE OF HVAC&R TECHNOLOGY AND APPLICATIONS ASHRAE.ORG
AA S S S S H H H H R R R R A A A A E E E E®
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M A R C H 2 0 1 5 a s h r a e . o r g A S H R A E J O U R N A L 3
FEATURES
STANDING COLUMNS
ASHRAE® Journal (ISSN 0001-2491) MISSION STATEMENT | ASHRAE Journal reviews current HVAC&R technology of broad interest through publication of application-oriented articles. ASHRAE Journal’s editorial content ranges from back-to-basics features to reviews of emerging technologies, covering the entire spectrum of professional interest from design and construction practices to commissioning and the service life of HVAC&R environmental systems. PUBLISHED MONTHLY | Copyright 2015 by ASHRAE, 1791 Tullie Circle N.E., Atlanta, GA 30329. Periodicals postage paid at Atlanta, Georgia, and additional mailing offices. LETTERS/MANUSCRIPTS | Letters to the editor and manuscripts for publication should be sent to: Fred Turner, Editor, ASHRAE Journal, [email protected]. SUBSCRIPTIONS | $8 per single copy (includes postage and handling on mail orders). Subscriptions for members $6 per year, included with annual dues, not deductible. Nonmember $79 (includes postage in USA); $79 (includes postage for Canadian); $149 international (includes air mail). Expiration dates vary for both member and nonmember sub scriptions. Payment (U.S. funds) required with all orders. CHANGE OF ADDRESS | Requests must be received at subscription office eight weeks before effective date. Send both old and new addresses for the change. ASHRAE members may submit address changes at www.ashrae.org/address. POSTMASTER | Send form 3579 to: ASHRAE Journal, 1791 Tullie Circle N.E., Atlanta, GA 30329. Canadian Agreement Number 40037127.
ONLINE at ASHRAE.org | Feature articles are available online. Members can access articles at no cost. Nonmembers may purchase articles at www.ashrae.org/bookstore. MICROFILM | This publication is microfilmed by National Archive Publishing Company. For information on cost and issues available, contact NAPC at 800-420-NAPC or www.napubco.com. PUBLICATION DISCLAIMER | ASHRAE has compiled this publication with care, but ASHRAE has not investigated and ASHRAE expressly disclaims any duty to investigate any product, service, process, procedure, design or the like which may be described herein. The appearance of any technical data, editorial material or advertisement in this publication does not constitute endorsement, warranty or guarantee by ASHRAE of any product, service, process, procedure, design or the like. ASHRAE does not warrant that the information in this publication is free of errors and ASHRAE does not necessarily agree with any statement or opinion in this publication. The entire risk of the use of any information in this publication and its supplement is assumed by the user.
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DEPARTMENTS 4 Commentary
6 Industry News
14 Meetings and Shows
88 Products
94 Classified Advertising
96 Advertisers Index
44 ENGINEER’S NOTEBOOK Return Air Systems By Steven T. Taylor, P.E.
48 BUILDING SCIENCES Forty Years of Air Barriers By Joseph W. Lstiburek, Ph.D., P.Eng.
72 DATA CENTERS Are Data Centers Drying Up? By Donald L. Beaty, P.E.; David Quirk, P.E.
26 Energy-Efficient Makeup Air Units By Hugh Crowther, P.Eng.
34 Part Two Radiant Heating and Cooling Systems
By Kwang Woo Kim, Arch.D.; Bjarne W. Olesen, Ph.D.
58 Control Sequences & Controller Programming
By Mark Hydeman, P.E.; Steven T. Taylor, P.E.; Brent Eubanks, P.E.
CONTENTS VOL. 57, NO. 3, MARCH 2015
2015 ASHRAE TECHNOLOGY AWARDS
16 2015 ASHRAE Technology Awards
64 Data Center Economizer Efficiency By Brett Griffin, P.E
78 Energy Efficient Ice Rink By Art Sutherland
7864
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ASHRAE Journal reviews current HVAC&R technology of broad interest through publication of applica-tions-oriented articles. Content ranges from back-to-basics features to reviews of emerging technologies.
COMMENTARY1791 Tullie Circle NEAtlanta, GA 30329-2305Phone: 404-636-8400Fax: 404-321-5478 | www.ashrae.org
PUBLISHER W. Stephen Comstock
EDITORIAL Managing Editor Sarah Foster [email protected]
Associate Editor Rebecca Matyasovski [email protected]
Associate Editor Christopher Weems [email protected]
Associate Editor Jeri Alger [email protected]
Assistant Editor Tani Palefski [email protected]
PUBLISHING SERVICESPublishing Services Manager David Soltis
Production Jayne Jackson Tracy Becker
ADVERTISINGAssociate Publisher, ASHRAE Media Advertising Greg Martin [email protected]
Advertising Production Coordinator Vanessa Johnson [email protected]
CIRCULATIONCirculation Specialist David Soltis [email protected]
ASHRAE OFFICERSPresident Thomas H. Phoenix, P.E.
President-Elect T. David Underwood, P.Eng.
Treasurer Timothy G. Wentz, P.E.
Vice Presidents Darryl K. Boyce, P.Eng.Charles E. Gulledge IIIBjarne W. Olesen, Ph.D.James K. Vallort
Secretary & Executive Vice President Jeff H. Littleton
POLICY GROUP2014 – 15 Chair Publications Committee Michael R. Brambley, Ph.D.
Washington Office [email protected]
Innovative SolutionsIt is a cliché to say that the only con-
stant is change, but “change” is an apt
descriptor of the state of affairs in the
field of building technology and con-
trolled environments. “Evolutionary”
and “dynamic” also work. This issue of
ASHRAE Journal offers ample evidence.
Take the ASHRAE cosponsored AHR
Expo. This issue has a full recap. The
2015 show that took place in January at
Chicago’s McCormick Place claimed the
title for the best-attended AHR Expo
ever with nearly 62,000 total attendees
from 35 countries and more than 11
acres of exhibits. At the ASHRAE con-
ference at the Palmer House downtown,
where ASHRAE standards writing and
technical committees met and engi-
neers from around the world presented
papers and engaged in topical discus-
sions, registration topped 3,000.
WHY THE interest? There have never
been more technology solutions to
choose from, enabling engineers to
improve building and system perfor-
mance. But you need to know what
options there are and under what cir-
cumstances they can best be applied.
That is how the Journal can help.
ASHRAE Journal offers examples of suc-
cessful choices in this issue’s recap of
the 2015 ASHRAE Technology Awards.
Nineteen projects have been singled out
for successful application of innovative
design that incorporate ASHRAE stan-
dards for effective energy management,
indoor air quality, and comfort.
A major criterion of the awards is energy
efficiency. Entries must comply with the
latest ASHRAE Standard 90.1 for new con-
struction and Standard 100 for exist-
ing buildings. Inclusion of one year’s
energy consumption data is strongly
encouraged. If not available, the results of
a nationally recognized computer model-
ing program employed to demonstrate
one year’s energy use is required.
Indoor air quality is another criterion.
Judges look for operating procedures,
source control of contaminants, sys-
tem commissioning and evidence that
design objectives have been achieved.
And they expect detailed descriptions
of compliance with ASHRAE Standard
55 and Standard 62.
ONE ELEMENT all the winning proj-
ects have in common is innovation.
Innovative elements of project designs
must be clearly described—especially
innovative application of technologies,
both old and new, to a particular situa-
tion. New technology or innovation itself
is not sufficient unless the needs of the
facility are truly met. The uniqueness of
the application is the basis of judgment.
There is much to learn through this
issue of ASHRAE Journal. Consider the
report on new products displayed at
AHR Expo and the recap of the ASHRAE
Technology Awards as your roadmap to
the change, evolution and dynamism
that is taking place in the industry today.
W. Stephen Comstock, Publisher
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 56
SHOW COVERAGE
FAST FACTSTotal Attendance ................61,674 (registered)**
Visitors ......................................................... 42,344*
Exhibiting Companies ................................2,118**
Percent Increase in Visitor Attendance Over 2012 Chicago Show ...........................................7%
Net Exhibit Space .................................. 486,600**
International Exhibitors ................................593**
Countries Represented ..................................... 35
Educational Sessions .......................................... 52
New Product Presentations ............................... 65
* Chicago record; ** All-time record
Record Breaker in ChicagoSold-Out ExpoSets SeveralAll-Time RecordsCHICAGO—The 2015 AHR Exposhattered several records and claimed the title for the bestattended event ever held in Chicago.
“Chicago is the site of some of our largest Shows and weare thrilled that we set so many new records this year,”said Clay Stevens, president of International ExpositionCompany. “These impressive results also show how vitalAHR Expo is to the industry.
“We’ve had tremendoussupport from the 41 sponsors and endorsing associationsthat participate, as well as from our exhibitors who relyon the Show to introduce new products and meet cus-tomers and prospects from around the world.”
This year’s Show was sold out for some time. It’s
the largest AHR Expo ever with more than 11 acres ofexhibit space.
Stevens attributes this partly
to the economy.“The exhibitor survey that
we did shows that there is even more optimism in theindustry than at last year’s show.”
Nearly 62,000 attended the show, which is an all-timerecord.
Show visitors seemedto agree that the econ-omy is picking up. Russ
Defuria, president of O’Brien Heating and AirConditioning in Drexel Hill, Pa., was attending the
Show for the first time. His company has 12 employeesand did about $2 million in business last year.
Defuria said there is pent-up demand in the residentialHVAC market.
“Last year was our best yearby far. People are loosening up with spending money.”
Bruce Cramer, vice president of Total Building
Environments South inTarpon Springs, Fla., attended his first Show 30 years ago,but had not attended in the past seven years. His energyservices company does energy savings projects for largebuildings. “With the down economy, not many busi-nesses were doing energy sav-ings projects. We had manylean years and were strug-gling to stay alive. Now theeconomy is picking up and it’s starting to get better.”
The next Show is in Orlando, Jan. 25–27, 2016.
Product of the Year CHICAGO—Danfoss’ Turbocor VTT (Variable Twin Turbo) Series Com-pressor is the winner of the 2015 AHR Expo Product of the Year.
The compressor was chosen from the products that won Innovation Awards in 10 industry-related cat-egories. The compressor features the company’s IntraFlow technology to provide high full- and part-load ef-ficiency.
Nearly 62,000 viewed displays of 2,100-plus exhibitors in more than 11 acres of exhibit space.
(L-R) Ken Anderson, Tim Rickards, Patrick Scantlebury, and Sean Giberson hear about Taco’s ECM high efficiency circulators from Steve Thompson.
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INDUSTRY NEWS
CHICAGO—Ten trends emerged from an online survey of AHR Expo exhibitors and attendees done by ASHRAE Journal. As in 2014, energy efficiency was the top trend from the more than 700 responses.EXHIBITORS1. Energy Efficiency “Energy con-servation, lower power consump-tion of pumps, recirculation.”2. New Technologies “Big trend is visualization of big data.”3. Costs/the Economy “End users looking for very low cost.”4. Sustainability “Green products.”5. Government “We need to get the government and EPA and all
regulatory agencies out of the industry and it will start to grow.”6. Training/Staffing “Lack of quali-fied/competent mechanical design engineers.”7. Environment “Environmental friendly refrigerants and equipment.”8. Fuel “Continuing dominance of natural gas in the heating marketplace.”9. Competition “More manufactur-ers are also starting to buy distri-bution chains to have direct access to the contractor channel.”10. O&M “Lack of owner awareness of overall system life costs with short-life, low-cost products installed.”
TOP TRENDS FOR 2015
ATTENDEES1. Energy Efficiency “I would expect energy efficiency to be a major driver for most markets with rising energy costs.”2. Costs/the Economy “Rising costs for mandated equipment.”3. New Technologies “DOAS units connected directly to terminal units, eliminating large AHUs and large insulated ductwork.”4. Training/Staffing “How do we hire, train, grow, develop, replace, the sales, operations and technical personnel who are retiring?”5. O&M “Contractor’s ability to
effectively start up and maintain newly released high-efficiency products.”6. Government “Regional stan-dards and how it will affect system sales.”7. Refrigerants “Concerns about the transition from R-404A to something else.”8. Competition “Every Tom, Dick and Harry trying to do HVAC.” 9. Environment “Energy saving and environment-friendly products.”10. Sustainability “Minimized energy consumption using heat recovery, net zero. Carbon reduction.”
Rami Al Soleiman (center) shows Matt Kadelback (left) and Daniel Hicks (right) images of the Petra Engineering Industries headquarters and facilities.
The 2015 AHR Expo shattered all-time records as well as records for the Chicago show. AHR Expo is in Chicago every third year and is typically the largest of the Shows.
What’s New at AHRCHICAGO—Here’s a sampling ofnew products shown at the AHR Expo and organized bycategory.
Air DistributionThe DT-ERV from Advantix
Systems is a packaged DOAS that combines liquid desic-cant technology with exhaust air energy recovery. Theunit maximizes ventilation air while reducing energyconsumption which encour-ages optimal air quality and areduced carbon footprint.
ALUAFS.70 UL non-insu-lated aluminum flexible air ducts from AFS are producedfor low and medium pressure heating, cooling, ventilation,exhaust and air condition-ing systems. Made frommulti-layer aluminum and polyester, the ducts have highelasticity and flexibility.
Air King’s Deluxe Quiet
series of range hoods aresuitable for continuous whole house, standard-com-pliant ventilation.
Used with Axial andCentrifugal fans, the new FlowGrid air-inlet grill fromebm-papst reduces ambient noise generated by high-performance technology. The diffuser lessens disturbancesin the fan inflow, minimizes disturbing low frequencytones caused by sound pres-sure in cooling, ventila-tion and air-conditioning systems.
Haier Flexfit ductless systems provide a solutionto mix and match different indoor units to the same out-door unit. This method helps distributors and contractorsreduce the time and cost of inventory management.
The Wireless Zone Control Damper from ALAN
Manufacturing Inc. is controlled by a handheld wireless remote control instead of a thermostat and is capable of controlling up to 32 different dampers in 5% increments.
The TSI-Alnor® EBT731
capture hood from TSI isa modular air balancing instrument designed to meetHVAC TAB and commission-ing requirements.
The all plastic Stratus dif-fuser from American Louveris indistinguishable from
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(L-R) Kouichi Minamigaito, Keiji Okuyama, and Shingo Mori admire a couple of sheet metal flanges by Mestek Machinery.
Albert Verkuylen gets a close look at the EC medium pres-sure axial fan from ebm-papst.
metal when installed. The diffuser issuitable for commercial and light com-mercial spaces and can be substituted inmost environments where metal units are currently used.
Selkirk’s multi-use models PS and IPS modular, prefabricated double wallventing/chimney/duct systems are com-monly used on appliances such as boil-ers, generators, turbines, kitchen hood grease duct, and coffee roasters.
The LG Art Cool Gallery Multi F indoor units areavailable in 9,000 and 12,000 Btu/h and are outfitted witha frame that allows the cus-tomer to modify and per-sonalize the unit with their own artwork or photography.Features include an inverter variable speed fan, self-cleaning coils, auto opera-tion, and auto restart opera-tion. Cooling is provided via R410A refrigerant and the Chaos Windmode electronically controls fan speeds to create a more natural flow of air whilethe Jet Cool mode operates at high fan speeds for 30 minutes to quickly cool aroom.
Building AutomationControl Solutions’ Babel Buster®
BB2-2010 is a bindable LonWorks® node that functions as a Modbus RTU RS-485master/slave. A large number of data objects provides flexibility in mappingModbus registers to scalar or structured LonWorks net-work variables.
SimplyVAV from KMC Controls is anative BACnet digital VAV controller/ actuator which can perform standaloneor networked VAV control without other software. The unit can be configured viaits companion sensor.
Schneider Electric offers BuildingInsights, a cloud-based system that pro-vides enterprise small buildings real-time visibility and control of all heating, ventilation and air conditioning (HVAC),
lighting and metering devices from anywhere atany time. The system offers facility managers two levelsof control: site-level and cloud-level for both wiredand wireless device control and a custom dashboardview on the cloud-level.
Petra’s air-handling unitcontrol offers a full range of system components frommaster controller and fre-
quency converter to temperature andpressure sensors. Together, the com-ponents can control fans, heating coils,cooling systems and drives for rotary heat exchangers.
Boilers/Water HeatingThe Unilux E-88 series boilers com-
bine the design and construction of pre-vious models with the ability to access the pressure vessel and fireside of theboiler. All units can either be factory assembled or field erected for replace-ment projects.
Marathon International offers the
Baxi Luna Duo-Tec 40 GA combinationcondensing boiler with gas-adaptive technology. The boiler features auto-matic de-aeration, continuous self-calibration, 7:1 modulation range, a two-stage pump, and multiple built-in safety components.
The HeatSponge Sidekick from Boilerroom Equipment retrofits con-ventional hydronic boilers to condens-ing and provides full condensing ofsteam boiler exhaust when a sufficient cold water heat sink exists.
Chillers/Cooling Towers/Chilled WaterSystems
Motivair’s Centricor water chiller, features Turbocor centrifugal compres-sors with magnetic bearings. Features optional free cooling for winter savingsand adiabatic cooling for peak ambient shaving. The PLC controls with remotecommunication and monitoring pro-vide peak performance and security.
The “Service-in-place” water cooled chillers from Tandem Chillers offersimultaneous heating/cooling without reversing the chiller making it easy to domaintenance and service. It is done in place with the rest of the equipment stilloperating.
EcoMESH Adiabatic Systems offersa mesh and water spray system that improves the performance of aircooled chillers, dry coolers and refrig-eration plants while reducing energyconsumption.
Combined Heating, Cooling/ChilledBeams
The Coolerado ERV offers newfunctionality over traditional ERVs. It extends Heat and Mass Exchanger(HMX) performance to all climates to provide cooling, de-humidification,heating and building pressurization.
REK+ from RECUTECH is an alu-minum counterflow air to air heat exchanger with optimized pressure loss,guaranteed maximum tightness and up to 95% efficiency.
The Alfa Laval AC1000 is a true dual circuit brazed plate heat exchanger.Designed for air conditioning, refrig-eration and heat pump applicationsincluding evaporation and condensa-tion, the AC1000 allows the customer
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SHOW COVERAGE
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to increase capacity up to 1200kW (341tons), while lowering system cost and boosting efficiency.
Thermalex specializes in manufac-turing difficult heat exchanger shapesused in automotive, commercial/resi-dential, electronic and aerospace heattransfer systems. The aluminum extru-sion products are available in a range
of alloys and coatings.MovinCool’s Climate Pro 18 portable
heat pump provides cooling (14,600Btu/h) and heating (13,700 Btu/h) capac-ity at 115V, 20 amps power. It is self-contained and features an LCD display with on-screen diagnostics as well asautomatic operation during after-hours.
The Hi-Velocity System from Energy
Savings Products is a small duct centralheating and air conditioning system, suitable for new construction, retrofits,historic remodels, recreational proper-ties, and commercial applications.
REHAU offers its radiant heating and cooling system featuring a network ofRAUPEX® O2 Barrier crosslinked poly-ethylene (PEXa) pipes. Used in combi-nation with a downsized air-handling system, the hydronic radiant heatingand cooling system can condition a space efficiently.
The DVM S WATER 20 HP air con-ditioning system from Quietside/Samsung HVAC features a dual inverter compressor with a high efficiency vaporinjection system to ensures rapid cool-ing and heating with minimum energyconsumption. A plate heat exchanger also improves the heat exchange effi-ciency and ensures stable cooling and heating performances.
CoolingEmbraco launches two R-290 com-
pressors for commercial coolers: theFullmotion with variable speed tech-nology and a High Efficiency “On-Off”version. These compressors will support manufacturers’ compliance with EPAand DOE 2017 guidelines.
SSE from Onda is a high efficiency lineof straight tubes dry-expansion evapo-rators. The new design is optimized forR-134a, featuring countercurrent flow, innovative straight tubes pattern andbaffles distribution.
The CCD Cooling Door fromClimaveneta functions as a stand-alone cooling unit for the exhaust air of thesingle rack in small data centers and as a system for managing hot spots in largedata centers, integrating hot and cold aisles or aisle containment structures.
HeatingThe Toyotomi heat convector model
hc-20 features an internal thermostatcontrol that allows the unit to commu-nicate to a zone valve or boiler control-ler. The variable fan speed maximizes operating efficiency.
Baseboarders from Buss General Partner Co. are slip-on baseboardheater covers. The product instantly transforms old functional baseboard
PEACE OF MIND COMES FROM MAKING THE RIGHT CHOICE.
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Contact us to learn more I www.foamglas.com I 1-724-327-6100 I 800-545-5001Protecting Companies and Their People WorldwideTM
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SHOW COVERAGE
heaters into modern archi-tectural highlights and fits all makes and models ofhydronic baseboard heaters from the past six decades.
Fujitsu General America, Inc. introduces theAirstageVR-II VRF heat recovery system that allowsfor simultaneous heat-ing and cooling operation.Energy efficiency doubles when the system provides
50% cooling and 50% heatingsimultaneously.
SunTherm’s ModularHydronic Furnaces, series model MMVE, offers 4-waymultiposition application and provides cooling airflow.All models offer variable speed, high efficiency, ECMmotors and can include optional factory-installed cir-culating pumps.
The InSpire wall panel fromATAS International is a solar air heating and drying systemthat is mounted on a build-ing’s outer wall. Solar-heatedair at the surface of the panel is drawn through perfora-tions where it rises between the two walls and enters thebuilding’s central ventilation system or supply fan.
Humidification/Dehumidification
DriSteem offers a line of
water pre-treatment andreverse-osmosis systems. These systems delivermineral-free water for a wide variety of applica-tions and processes beyond humidification. The systemscan integrate with building automation systems using acontroller.
Indoor Air QualityThe Bi-Polar 2400 from
Air Oasis is a filterless cold plasma air purifier the sizeof a smart phone. The unit installs in almost any system,ducted or not and is water resistant.
The Wi-Fi enabled FILTERSCAN Air FilterMonitor and Notification System from CleanAlertsends notifications via local, text and e-mail alerts when afilter needs servicing by mea-suring differential pressure
changes in a HVAC system.C Cloud Filter’s V-Bank
filters are designed for usein commercial, industrial, manufacturing and medicalfacilities. Filters are available from MERV 13-16 and featurelow air pressure drop and long filter life.
The GeneralAire PCO2450 VectorFlo photocatalytic
Becky Trujillo, Trane Commercial, shows Clive Broadbent the Sintesis air-cooled liquid chiller.
Haixia Li poses with a brass and steel brazed statue of Joe Harris, founder of Harris Products Group.
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See Products, Page 90
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oxidation air purifier fea-tures a patented semicon-ductor designed to deliver ahigh-performance kill rate. It reduces germs, bacteria, andviruses in your home.
LightingThe SwitchSense™ bat-
tery backup LED driver from Wireless Environmentworks in conjunction with an AC LED driver to add abattery backup to new or existing LED luminairesor lamps. The patented technology eliminates theneed to wire an unswitched connection to the control-ling switch. The embedded switch sensing capabilityallows a luminaire or lamp to be installed as a retrofit,making use of existing wir-ing to add power outage
lighting functionality to theluminaire.
Philips offers the LUXEON3535 HV mid-power surface-mount-device (SMD) LEDthat comes in both 24V and 48V configurations. The highvoltage and lower current lead to an efficient driverand allows for a reduction in LED count with better lightextraction. The LEDs are available in a color tempera-ture range of 2700–5000K.
Motors, Drives, CompressorsDomel’s EC motors use
ferrite magnets and feature low noise, low weight, and acompact design. The motor design protects it from dustand allows it to operate in a wide range of temperatures.
Browning introduces an expanded range of sizes for
its self-tensioning Tenso-setmotor base. The expanded product range for the energy-saving Tenso-set base will include up to NEMA 447 andequivalent IEC motor frame sizes.
Designed for the HVAC industry, TriangleManufacturing’s direct drive motor mounts feature noisesuppression, knock down shipping and customizability.The motors’ arms and bands are shipped unassembledand can reduce needed ware-house space and shippingcosts.
The CSVW2 compact screwcompressors from BITZER are for use in water cooledchillers for systems with low saturation dischargetemperatures and which are equipped with new
permanent magnet motors.These motors are more efficient than conventionalmotor technologies at lower speeds and loading ranges.
PlumbingAquatechnik Group
manufactures white pipesand fittings of PP-R 80 SUPER for polyfusion weld-ing. They are suitable for all plant-engineering systems,particularly for the transport of potable and non-potable,warm and cold fluids, with a working temperature up to200°F (93°C).
Niccons Italy offers line-setprotection, made of rigid PVC without lead, for air-condi-tioning installations. Available in several measurements,the system allows a total and
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MEETINGS AND SHOWS FULL CALENDAR: WWW.ASHRAE.ORG/CALENDAR
CALLS FOR PAPERSASHRAE JOURNAL ASHRAE Journal publishes applications-oriented articles that are 3,000 or fewer words. Graphics are encouraged. All ar-ticles are subject to editorial and peer reviews and cannot have been pub-lished previously. Authors should sub-mit abstracts before sending articles to [email protected].
SCIENCE AND TECHNOLOGY FOR THE BUILT ENVIRONMENTASHRAE’s Science and Technology for the Built Environment (previously known as HVAC&R Research Journal) seeks papers on origi-nal, completed research not previously published. Papers must discuss how the re-search contributes to technology. Papers should be about 6,000 words. Abstracts and papers should be submitted on Manuscript Central at www.ashrae.org. For more infor-mation, contact Reinhard Radermacher, Ph.D., Editor, at [email protected].
ASHRAE CONFERENCE PAPERS ASHRAE seeks papers for presentation at Society Conferences. For the 2016 Winter Conference in Orlando, Fla., conference paper abstracts are due March 23, 2015. For more information, contact 678-539-1137 or [email protected].
MARCHHVACR & Mechanical Conference for Educa-tion Professionals, March 9 – 11, Baltimore. En-dorsed by ASHRAE. Contact Warren Lupson at 703-600-0308, [email protected], or www.instructorworkshop.org.
IAQA Annual Meeting and Indoor Environment and Energy Expo, March 16 – 18, Grapevine, Texas. Contact the Indoor Air Quality Association at 844-802-4103, [email protected], or www.iaqa.org.
AEI Conference, March 24 – 27, Milwaukee. Con-tact Elaine V. Watson, American Society of Civil En-gineers, at [email protected] or www.asce.org/aeiconference2015.
APRILNEBB Annual Conference, April 16 – 18, Honolulu. Contact the National Environmental Balancing Bureau at 301-977-3698 or www.nebb.org/events.
MAYLightfair International, May 3 – 7, New York. Con-tact organizers at 404-220-2220, [email protected], or www.lightfair.com.
EE Global 2015, May 12 – 13, Washington D.C. Con-tact Becca Rohrer, Events Associate as Alliance to Save Energy at 202-0530-2206, [email protected], or www.eeglobalforum.org.
AIA Convention 2015, May 14 – 16, Atlanta. Con-tact the American Institute of Architects at 800-242-3837, [email protected], or www.aia.org/convention.
AIHce 2015, May 30 – June 4, Salt Lake City. Contact Lindsay Padilla at the American Industrial Hygiene Association at 703-846-0754, [email protected], or www.aihce2015.org.
JUNEASHRAE Annual Conference, June 27 – July 1, Atlanta. Contact ASHRAE at 800-527-4723 or [email protected].
Every Building Conference and Expo, June 28 – 30, Los Angeles. Contact the Building Owners and Managers Association at 202-326-6331, [email protected], or www.bomaconvention.org.
JULY Solar 2015, July 28 – 30, State College, Pa. Contact 303-443-3130, [email protected], or http://solar2015.ases.org.
AUGUST NAFA Annual Convention, Aug. 27 – 29. Key West, Fla. Contact the National Air Filtration Associa-tion at 757-313-7400, [email protected], or www.nafahq.org.
SEPTEMBERSMACNA Annual Convention, Sept. 27 – 30, Colo-rado Springs, Colorado. Contact the Sheet Metal and Air Conditioning Contractors’ Association at 703-803-2980, [email protected], or www.smacna.org.
RETA Conference, Sept. 29 – Oct. 2, Milwaukee. Contact the Refrigeration Engineers and Techni-cians Association at 831-455-8783, [email protected], or www.reta.com.
World Energy Engineering Congress, Sept. 30 – Oct. 2, Orlando, Fla. Contact the Association of
Energy Engineers at 770-447-5083, [email protected], or www.energycongress.com.
OCTOBERIFMA’s World Workplace, Oct. 7 – 9, Denver. Con-tact the International Facility Management Asso-ciation at 713-623-4362, [email protected], or www.ifma.org.
AHR Expo-Mexico, Oct. 20 – 22, Guadalajara, Mex-ico. Contact the International Exposition Compa-ny at 203-221-9232, [email protected], or www.ahrexpomexico.com.
CTBUH 2015, Oct. 26 – 30, New York. Contact the Council on Tall Buildings and Urban Habitat at 312-567-3487, [email protected], or www.ctbuh2015.com.
NOVEMBERGreenbuild International Conference & Expo, Nov. 18 – 20, Washington, D.C. Contact organizers at 866.815.9824, [email protected], or www.greenbuildexpo.com.
2016JULY2016 Purdue Compressor/Refrigeration and Air Conditioning and High Performance Buildings Conferences and Short Courses, July 11 – 14, West Lafayette, Ind. Contact Kim Stockment, Conference Coordinator at 765-494-6078, [email protected], or http://tinyurl.com/Purdue2016.
OCTOBERASPE Convention and Exposition, Oct. 27 – Nov. 4, Phoenix. Contact the American Society of Plumb-ing Engineers at 847-296-0002, [email protected], or www.aspe.org.
OUTSIDE NORTH AMERICAMARCHISH 2015, March 10 – 14, Frankfurt, Germany. Contact 49 69 75 75 0 or www.ish.messefrankfurt.com.
APRILChina Refrigeration, April 8 – 10, Shanghai. Con-tact organizers at [email protected] or www.cr-expo.com.
International Conference on Fan Noise, Tech-nology and Numerical Methods (FAN 2015), April 15 – 17, Lyon, France. Contact www.fan2015.org.
CIAR 2015, April 28 – 30, Madrid. Contact [email protected] or www.ciar2015.org.
MAYMostra Convegno Expocomfort Saudi, May 4 – 6, Riyadh, Saudi Arabia. Contact Reed Exhibitions at 39 02 4351701, fax 39 02 3314348, [email protected] or www.mcexpocomfort.it.
Advanced HVAC and Natural Gas Technolo-gies 2015, May 6 – 9, Riga, Latvia. Endorsed by ASHRAE. Contact Agnese Lickrastina, Riga Techni-cal University at [email protected] or www.hvacriga2015.eu.
2015 International Conference on Energy and En-vironment in Ships, May 22 – 24, Athens, Greece. Contact ASHRAE at 800-527-4723, [email protected], or www.ashrae.org/Ships2015.
JULYISHVAC-COBEE 2015, July 12 – 15, Tianjin, China. Endorsed by ASHRAE. Contact organizers at [email protected] or http://www.cobee.org.
AUGUSTBangkok RHVAC, Aug. 14 – 16, Bangkok. Contact the Office of Agriculture and Industrial Business Devel-opment at 66 (0) 2507 8374-8, [email protected], or www.bangkok-rhvac.com.
IIR International Congress of Refrigeration, Aug. 16 – 22, Yokohama, Japan. Endorsed by ASHRAE. Contact 81 3 3219 3541, [email protected], or www.icr2015.org.
SEPTEMBERMostra Convegno Expocomfort Asia, Sept. 2 – 4, Singapore. Contact Reed Expositions Singapore at 65 6780 4671, fax 65 6588 3832, [email protected] or www.mcexpocomfort-asia.com.
OCTOBER8th International Cold Climate HVAC Confer-ence, Oct. 20 – 23, Dalian, China. Endorsed by ASHRAE. Contact organizers at 86 411 84709612, [email protected], or www.coldclimate2015.org.
11th International Conference on Industrial Ventilation, Oct. 26 – 28, Shanghai. Endorsed by ASHRAE. Contact 86 21 65984243, [email protected], or www.ventilation2015.org.
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TechnologyAwards
ASHRAE Technology Awards recognize outstanding achievements by members who
have successfully applied innovative building design in the areas of occupant comfort,
indoor air quality and energy conservation. Their designs incorporate ASHRAE standards
for effective energy management and IAQ. Performance is proven through one year’s
actual, verifiable operating data.
This year’s awards recognize buildings designed for a range of occupant types and uses
including penguins, patients, skaters, students, government employees and water testers.
The following describes projects from the 2015 ASHRAE Technology Awards winners and
honorable mentions. Articles about these projects will be published in future issues of
ASHRAE Journal and High Performing Buildings magazine.
2015 ASHRAE
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 1 7
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
FIRST PLACEBENJAMIN FRANK GOZART, ASSOCIATE MEMBER ASHRAEFEDERAL CENTER SOUTH – BUILDING 12021, SEATTLE
Federal Center South used an
integrated design approach that
focused on energy conservation
measures vs. expensive on-site
energy generation strategies.
Several innovative technologies
include: passive chilled sails; ther-
mal storage using phase change
material; a 100% outside air venti-
lation system with heat recovery of
exhaust serving a raised floor ven-
tilation air distribution system;
and heat recovery chillers tied to
a high efficiency low temperature
heating/high temperature cooling
hydronic system.
FIRST PLACEROGER (JUI-CHEN) CHANG, P.E., BEMP, MEMBER ASHRAEWAYNE N. ASPINALL FEDERAL BUILDING AND U.S. COURTHOUSE
FIRST PLACEBRIAN A. HAUGK, P.E., MEMBER ASHRAEVALLEY VIEW MIDDLE SCHOOL
The project converted a 1918
landmark into one of the most
energy efficient, sustainable
historic buildings in the coun-
try. To meet aggressive perfor-
mance goals, including energy
independence and energy effi-
ciency, the design included: a
roof canopy-mounted 123 kW
PV array; addition of spray foam
and rigid insulation to building
shell; storm windows with solar
control film to reduce demand
on HVAC; and VRF heating and
cooling systems tied to a 32-well
geoexchange loop.
A water-to-water heat pump
(WWHP) allowed the design team
to use displacement ventilation,
which requires very tight dis-
charge air temperature control,
to maintain occupant comfort
only achievable with a WWHP
system. This project was one of
the first to use this technology in
the region and fully integrates
the factory controls with the EMS
system.
PHOTO: KEVIN G. REEVES, PHOTOGRAPHER, COURTESY OF WESTLAKE REED LESKOSKY
PHOTO: BEN BENSCHNEIDER
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
FIRST PLACEMATTHEW WILLIAM LONGSINE, P.E., ASSOCIATE MEMBER ASHRAETACOMA CENTER FOR URBAN WATERS, ZEELAND, MICH.
The 51,000 square foot lab
facility functions as a shared
research facility for the City
of Tacoma, the University of
Washington and Puget Sound
Partnership. It focuses on receiv-
ing and analyzing water samples
from the waterways of Tacoma
and surrounding areas.
Design features include heat
recovery, energy efficient light-
ing, daylighting, natural ventila-
tion, radiant floors, low-e glass
and exterior operable shading,
VAV low flow fume hoods, and
rainwater harvesting.
FIRST PLACEKATERI HÉON,ING., ASSOCIATE MEMBER ASHRAECENTRE CIVIQUE DE DOLLARD-DES-ORMEAUX
An energy-efficiency program
was developed to increase the
performance of the refrigeration
system for three indoor rinks
and then to recover the energy
rejected from the center com-
pressors to heat the building.
The design team chose a system
that featured a direct carbon
dioxide heating and regenera-
tion of a dehumidifier desiccant
wheel, which is the first time this
system has been used in a rink in
North America. The system also
is the first to use carbon dioxide
in a multi-rink complex.
FIRST PLACEMARK STAVIG, MEMBER ASHRAEPEACE ISLAND MEDICAL CENTER
Island resources are limited,
which made sustainable choices
vital and simple design neces-
sary. The mechanical system was
designed to use only electric-
ity, the only available energy
source on the island. The project
employs numerous energy effi-
ciency measures and achieves an
average EUI of 87.7 kBtu/square
foot per year.
A conscious effort was made to
reduce cooling demand resulting
from building envelope and plug
loads.
PHOTO: BEN BENSCHNEIDER
1 8 A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 5
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 52 0
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
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2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
FIRST PLACEWILLIAM C. WEINAUG JR., P.E., MEMBER ASHRAEANTARCTICA: EMPIRE OF THE PENGUIN
When creating a 32°F space
in hot and humid Orlando, the
efficiency of the systems and
envelope is crucial. The facility
is designed to minimize energy
use while providing a habitat for
penguins to thrive.
In regard to thermal comfort,
the criteria were driven by birds’
comfort instead of humans.
Human comfort was measured
by how well odors were con-
trolled. Designers also had to
protect the birds from mold and
fungi not common to their native
environment.
FIRST PLACEARTHUR GILBERT SUTHERLAND, MEMBER ASHRAEWESTHILLS RECREATION CENTER
The mechanical system for the
three ice surfaces are integrated
into the building HVAC system
to the extent that no fossil fuels
are used for the facility other
than in the kitchen. The outdoor
rink offers an interesting energy
balance opportunity in winter
by providing additional rejected
energy during the heating sea-
son. Even with the extensive
use of energy, only 40% of waste
energy is required within the
complex. The remaining 60%
is pumped to a nearby housing
development.
FIRST PLACEJASON TROY LAROSH, P.E., MEMBER ASHRAEJANESVILLE ICE ARENA ADDITION AND RENOVATION
The project included renova-
tion of the existing 26,000 square
foot arena with the addition of
2,000 square feet that included
new locker rooms, an ice resur-
facing melt pit and resurfacing
equipment storage area.
The original ice refrigeration
system, installed in 1964, was a
direct refrigeration system that
used R-22 refrigerant circulated
in piping embedded in the floor.
The new system incorporates a
pond loop geothermal system
to handle the high refrigeration
needs of the arena.
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 52 2
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 52 2
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
SECOND PLACEPERRY HAUSMAN, MEMBER ASHRAE, CORPORATION HALLFor this mixed use building, sustainable features include a green roof, lowflow plumbing fixtures, high-efficiency mechanical units, low consumption LED lighting, lighttubes, solar thermal energy, geo-thermal silent heat through the radiant floor and a non-idling demand response snowmelt system.
STANLEY KATZ, ASSOCIATE MEMBER ASHRAE, COMPLEX SOUTHWEST ONEThe addition of a new radiology clinic at a residential complex challenged the design team to reduce the impact of the clinic on the residential complex dur-ing and post construction. The design team used heat recovery and a new chiller without a cooling tower.
ERIC WILLIAM SHAW, MEMBER ASHRAE, UPPER THAMES RIVER CONSERVATION AUTHORITYThe design of this administrative building combines innovative technologies and good practice, achiev-ing a 71% reduction in energy use over the regu-lated requirements for energy efficient buildings (MNECB). Compared to ASHRAE/IES Standard 90.1-2007, the estimated energy savings was 56%.
Corporation Hall
ComplexSouthwest One
AARON ROBERT SMITH, P.ENG., MEMBER ASHRAE, 100 VENTURE RUN100 Venture Run is a three-story office building in Nova Scotia that achieved LEED Canada Gold Core and Shell 2009; the first LEED Gold Core and Shell project in the province. This building is to be used as a template for future buildings at the site so building performance was analyzed early in the design process and a rigorous commissioning and measurement and verification process took place.
HONORABLE MENTION
JACQUES LAGACÉ, ING, MEMBER ASHRAE, COMMISSION DE LA CONSTRUCTIONDU QUEBECThis office building design began with a thoroughanalysis of the data center to capitalize on its opera-tion and needs so as to effectively adapt the buildingservices to them. The design reclaimed energy pro-duced by the data center and used it efficiently.
DONALD J. MCLAUCHLAN, P.E., MEMBER ASHRAE, SUN LIFE ASSURANCE COM-PANY 29 NORTH WACKER RENOVATION PROJECTAn ASHRAE Level II audit identified 10 energy con-servation measures for this existing building such asa steam-to-water conversion, a chilled water plantoverhaul, redesign of the perimeter HVAC system toincorporate active chilled beams, a new interior VAVsystem and refurbishment of AHUs.
JEAN-PHILIPPE MORIN, ASSOCIATE MEMBER ASHRAE, CSSS POINTE-DE-L’ILEAn ASHRAE Level III audit identified energy-effi-ciency measures for this existing building such as air-to-air heat-recovery systems; geothermal heating sys-tem; condensing boilers retrofit; kitchen hood systemvariable flow conversion; and condensing hot-waterheaters retrofit.
BRETT MASON GRIFFIN, MEMBER ASHRAE, DIGITAL REALTY DATA CAMPUSThe heart of the mechanical system for this data cam-pus is the chiller plant. Due to aggressive speed tomarket and flexibility requirements, the chiller plantwas designed to be modular and scalable to allow forthe plant to be stick built onsite or pre-built offsite.
CHARLES E. GULLEDGE, III, MEMBER ASHRAE, CATERPILLAR ASSEMBLY PLANTThe Caterpillar Assembly Plant is a new, state-of-the-art, heavy manufacturing facility in Georgia. The proj-ect was completed via a design-build delivery modelon a greenfield site.
TERRY G. AUTRY, P.E., MEMBER ASHRAE, NCAR-WYOMING SUPERCOMPUTING CENTERTo achieve high levels of cooling system efficiency,RMH engineers harnessed the cool, dry climate ofCheyenne by using evaporative cooling towers to effi-ciently deliver 65ºF chilled water directly to NCAR’sliquid-cooled supercomputers for 98.6% of the year.That same 65ºF chilled water is moved into fan wallcooling coils for the air-cooled computers.
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 52 6
TECHNICAL FEATURE
Hugh Crowther, P. Eng., is a consultant to Price Industries. He is past chair of ASHRAE Standards Committee.
BY HUGH CROWTHER, P.ENG., MEMBER ASHRAE
Energy-EfficientMakeup Air Units Air Units AirUnless you live in paradise, delivering makeup delivering makeup delivering air to most buildings is expensive.Table 1 shows the amount of work of work of it takes to heat and cool air (based on Chicagoconditions) for a standard rooftop unit (a unit that recirculates air with typical airconditioning loads)conditioning loads)conditioning and a makeup air (MUA) unit. Note the standard unit conditionsrepresent 400 cfm/ton (53.68 L/[s·kW]) with 80°F dry bulb/67°F dry bulb/67°F dry wet bulb (26.7°C drybulb/19.4°C wet bulb) return air conditions. It can be seen that a MUA unit MUA unit MUA requiresmore than twice the cooling and cooling and cooling five times the heating work heating work heating as a standard unit.
For many HVAC solutions a dedicated outdoor air
system (DOAS) is required such as variable refriger-
ant flow systems (VRF), ground source heat pumps
(GSHP), and chilled beams (Figure 1). Many process
applications (labs, industrial processes, garages, etc.)
also require makeup air (MUA) systems. All these
applications require some form of make up air unit
that can move and filter outdoor air as well as heat
and cool (depending on location and application).
Since these units consume significant energy in most
applications, a discussion on how to improve their
efficiency is warranted.
A basic MUA unit has to meet certain minimum per-
formance requirements:
• 80% efficient (indirect fired) gas heat1 (assuming a
gas heat unit);
• 10 EER (Energy Efficiency Ratio)2 if DX cooling is
required;
• Fan performance is generally marginalized but is
accounted in the unit EER requirement (assuming there
is cooling); and
• Basic wall construction called out in the product
specification. A basic unit is typically single wall, 0.5 to 1
in. (13 to 25 mm) fiberglass insulation.
To move beyond a basic unit, four areas of improve-
ment will be considered: gas heat, DX cooling, fan per-
formance, and casing performance (Figure 2). The energy
usage calculations are based on a 10,000 cfm (4700 L/s)
MUA unit in Chicago. The cost3 of gas is $0.79/therm
and electricity is $0.10 kWh. The carbon dioxide (CO2)
equivalent conversion4 for natural gas is 0.510 CO2e
lb/kWh (0.232 kg/kWh) and for electricity is 1.670 CO2e
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 2 7
TECHNICAL FEATURE
lb/kWh (0.758 kg/kWh). Calculations are based on 24/7
operation.
Improving Gas HeatingTo improve gas heating the efficiency needs to be
increased. Gas heat efficiency is heat added to the air-
stream/heat released in the combustion of the fuel. By
code, MUA units need to have 80% minimum efficiency.
Technology is now available to raise the heating effi-
ciency of MUA units to 90% or greater (Photo 1). However,
this results in acidic condensation of water vapor in the
combustion gas. As well, the increased heat exchanger
surface area increases the air pressure drop by approxi-
mately 0.10 in. w.c. (25 Pa), which will increase fan work.
Condensing boilers have been gaining acceptance for
some time now but they are located in a boiler room
with a floor drain. A condensing gas furnace in a roof
mounted MUA unit requires careful planning both by
the design engineer and the installing contractor, par-
ticularly if the ambient falls below freezing. It is recom-
mended that the condensate be routed down through
the roof curb to a drain within the building. If the con-
densate must be exposed to freezing conditions, heating
tracing should be applied. Local codes may also require
pH neutralizing kits.
Table 2 compares the natural gas savings between an
80% efficient and 90% efficient furnace. The savings in
natural gas and operating cost are around 11%. In this
application it is about a two-year payback.
Improving DX CoolingMinimum efficiencies for package rooftop units
in a recirculation application are provided in
ASHRAE Standard 90.1. The efficiencies are based
on AHRI Standard 340/360 that assumes 80°F/67°F
(26.7°C/19.4°C) dry bulb/wet bulb entering air condi-
tions. Since a MUA unit sees more demanding loads,
the efficiencies listed are not generally obtained. Since
the airflow rate per unit of cooling is typically half in
a MUA unit (i.e., 200 cfm/ton [26.84 L/s·kW]) versus a
recirculating unit (i.e., 400 cfm/ton [53.68 L/s·kW]), it
is often not possible to operate a MUA unit at the condi-
tions stated in AHRI Standard 340/360. The end result is
that cooling efficiency targets for MUA units are not well
established and are left up to the designer.
TABLE 1 MUA energy requirements.
DESIGN CONDITIONS
DRY BULB/WET BULB °F Δ ENTHALPY
(BTU/H · CFM)COOLING WORK
(W/CFM)HEATING WORK (BTU/H · CFM)
STANDARD UN IT
80/67 to 57.6/57 30 3.0
54.1 to 70 (20% OA) 16 19
MUA UN IT90/75 to 55/54.5 70 7.0
–1.5 to 70 78 97
FIGURE 1 Typical make-up air system.
PHOTO 1 Ninety percent gas furnace.
FIGURE 2 High performance MUA unit.
Gas HeatFans
Cabinetry
DX Cooling
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 52 8
Energy efficiency ratio (EER) is the total cooling
capacity (Btu/h)/electrical power for supply air fans,
condenser fans, and compressors (W). Since supply fan
work will be discussed separately, let’s assume an EER of
10 for just the compressors and condenser fans at MUA
conditions for a basic unit and an EER of 11 for a high
efficiency unit. As well, it is assumed that dehumidifica-
tion is required and thus the air will be cooled to 55°F
(12.8°C). (where neutral air temperatures are required,
DX cooled makeup air units often include hot gas reheat,
which uses waste heat to warm the air).
Table 3 shows the savings are around 9% with a four-
year payback. Location has a lot to do with the payback.
Moving the location from Chicago to Miami would
greatly improve the payback for the improved cooling
efficiency.
Supply Fan SavingsIndirect fired MUA units must have the fans in a
blow-through position relative to the furnaces. This is
a safety issue. The most cost-effective fans are forward-
curved scrolled fans, but they discharge into an open
plenum, which is not an ideal application. There is little
static pressure regain without discharge ductwork. For
scrolled fans, this loss is usually accounted for by adjust-
ing the total static pressure (TSP) for the system loss
or by using fan curves that are based on actual testing
with a scrolled fan in a blow-through arrangement. In
this case, the TSP was increased by 0.2 in. w.c. (50 Pa)
to account for the system effect and will impact the fan
efficiency.
Optional fan arrangements include airfoil scrolled
fans, and belt and direct drive plenum fans. Belt drive
units have a drive loss around 2% while direct drive fans
will require a VFD that will introduce a drive loss around
2%. From an energy point of view for constant volume
applications, direct (VFD) and belt drive losses are about
equal.
Table 4 summarizes the impact of different fan choices
using 3 in. w.c. (750 Pa) total static pressure for a 10,000
cfm (4700 L/s) unit operating 24/7.
The energy savings from worst to best is 28% and has
a less than two-year payback. The direct drive plenum
fans also offer reduced maintenance (no belts) and the
ability to vary the supply airflow for further energy sav-
ings (depending on the building application).
Casing SavingsCasing energy losses take two forms; thermal losses
through the cabinet wall and exfiltration (air leakage on
the positive pressure side of the fan). Exfiltration adds
a secondary loss in that the supply fan airflow rate will
likely be increased (through the testing and balancing
process) to deliver the correct airflow to the point of use
thus increasing the fan work and likely the heating and
cooling work.
TABLE 3 DX cooling savings.
TEMPERATURE RANGE
(°F)
NUMBER OF OCCURRENCES
(HR)
COOLING LOAD
(BTU/H)
10 EER 11 EER
ELECTRICITY USAGE
(W)
COST($)
ELECTRICITY USAGE
(W)
COST($)
90 to 100 48 1,288,800 128,880 330 117,164 299
80 to 90 466 996,300 99,630 2,207 90,572 2,007
70 to 80 1,234 661,050 66,105 4,050 60,095 3,682
60 to 70 1,480 248,400 24,840 1,659 22,582 1,508
Totals 3,228 8,247 7,497
TABLE 4 Fan savings.
FAN TYPEAIRFLOW
(CFM)FAN WORK
(W)ANNUAL WORK
(KWH)ANNUAL COST
($)
Twin FC Scrolled Fans 10,000 6,833 59,860 5,986
Twin AF Scrolled Fans 10,000 5,655 49,535 4,953
Belt Drive Plenum Fan 10,000 5,252 46,006 4,601
Direct Drive Plenum Fan 10,000 4,939 43,261 4,326
TABLE 2 Gas heat savings.
TEMPERATURE RANGE
(°F)
NUMBER OF OCCURRENCES
(HR)
HEAT LOAD (BTU/H)
80% EFFIC I ENCY 90% EFFIC I ENCY
GAS USAGE(CFH)
COST ($)
GAS USAGE(CFH)
COST($)
65 to 75 1,252 108,500 132 638 117 567
55 to 65 1,472 325,500 397 2,230 353 1,982
45 to 55 1,204 542,500 662 3,147 588 2,797
35 to 45 1,380 759,500 926 5,172 823 4,597
25 to 35 1,396 976,500 1,191 6,506 1059 5,783
15 to 25 648 1,193,500 1,456 3,731 1293 3,316
5 to 15 202 1,410,500 1,720 1,359 1529 1,208
–5 to 5 88 1,627,500 1,984 683 1765 607
–15 to (–5) 28 895,125 1,092 241 970 215
Totals 7,642 23,706 21,072
TECHNICAL FEATURE
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assumed to be 4% while for the high performance cabi-
net the leakage rate is assumed to be 1%.5
Table 5 shows that a high performance cabinet can offer
a 77% savings and that cabinet leakage is three to five
times more important than thermal loss. The savings are
comparable to DX cooling improvement for this climate.
Summary and ConclusionsTable 6 summarizes the savings that are possible by
using equipment that performs beyond the minimum
requirements. The energy savings for all improve-
ments are 14%, and the cost savings are around $6,000/
yr. This works out to around $0.60/supply air cfm per
year ($0.29/supply air L/s per year). Assuming a 20%
premium for the high-performance unit, the payback is
around two years. Smaller units will have a higher pre-
mium and hence a longer payback. Since a MUA unit is a
high energy consuming device, investing in greater than
minimum efficiency performance is generally a good
design goal and offers a better return on investment
than upgrading other components in the HVAC system.
Table 6 also shows the CO2 equivalent savings based on
factors from ASHRAE Standard 189.1. The CO2 reduction
is almost 110,000 lbs/yr.
Not all the reviewed improvements are equal in sav-
ings and some are location dependent. Fan improve-
ment savings are universal in terms of location. Any
improvement to the fan system will deliver good
results as long as the unit is running. Cabinet perfor-
mance is also fairly universal. The bulk of the energy
penalty comes from leakage so the weather conditions
at point of use are less of an influence. Cold weather
climates benefit more from better thermal perfor-
mance than hot climates (the temperature differences
are larger).
Cooling and heating savings are heavily dependent on
location. Miami will enjoy a fast payback on improved
cooling efficiency while Winnipeg will see the same for
the high-performance furnace. In this example, the
improved cooling in Chicago has the longest payback
due to the low BIN hours of operation. In Miami, cooling
would be one of the most important improvements. The
designer should take this into account when specify-
ing equipment. A quick review of the BIN hours for the
TABLE 5 Casing savings.
BASIC CAB INET H IGH PERFORMANCE CAB INET
CAB INET HEAT LOSS INFI LTRATION CAB INET HEAT LOSS INFI LTRATION
TEMPERATURE RANGE DB
(°F)
NUMBER OF OCCURANCES
(HR)
LOAD (BTU/H)
COST ($)
HEAT LOAD (BTU/H)
COST ($)
HEAT LOAD (BTU/H)
COST ($)
HEAT LOAD (BTU/H)
COST($)
90 to 100 48 6192 1 32,832 9 953 0 8,208 2
80 to 90 466 3,096 6 21,132 45 477 1 5,283 11
70 to 80 1234 629 4 7,722 47 97 1 1,931 12
60 to 70 1480 1,935 14 8,680 65 298 2 2,170 16
50 to 60 1187 3,870 22 17,360 99 595 3 4,340 25
40 to 50 1058 5,805 29 26,040 131 893 5 6,510 33
30 to 40 1739 7,740 65 34,720 290 1,191 10 8,680 72
20 to 30 896 9,675 41 43,400 185 1,488 6 10,850 46
10 to 20 461 11,610 25 52,080 113 1,786 4 13,020 28
0 to 10 132 13,545 9 60,760 38 2,084 1 15,190 10
–10 to 0 59 15,480 4 69,440 20 2,382 1 17,360 5
Totals 8760 221 1,041 34 260
A basic unit casing in a MUA
unit is typically single-wall steel
with 0.5 in. to 1 in. (12 to 25 mm)
fiberglass insulation glued to it.
The R value will be around 2. A
high performance casing will be
2 in. (51 mm) injected foam con-
struction with an R value around
R-13. The supply air pressure will
cause deflection in the cabinet
walls. Deflection creates open-
ings that lead to air infiltra-
tion or exfiltration. Single-wall
construction units can have
significant deflection and thus
leakage.* Injected foam cabinets
are very rigid and can have a
deflection of less than L/240. For
a basic cabinet the leakage rate is
TABLE 6 Savings summary.
SAV INGS ITEM
BASIC (KWH)
H IGH PERFORMANCE
(KWH)DI FFERENCE
(KWH) PERCENT $/YR CO2
GAS 901,508 801,341 100,167 11 2,634 51,085
DX COOLING 82,470 74,973 7,497 9 750 12,520
FANS 59,860 43,261 16,599 28 1,660 27,720
CASING 45,370 10,562 34,808 77 968 18,420
TOTAL 1,089,208 930,137 159,071 6,012 109,745
* It is possible to build a single-wall casing with fiberglass insulation that has a deflection of L/240 or less. Many high-end custom AHU manufacturers do this. It is less common in packaged rooftop units.
TECHNICAL FEATURE
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 53 2
project location should point out where to recommend
increased product performance.
Operating hours will also impact savings. For this anal-
ysis, the assumption was 24/7 operation. In many appli-
cations, the MUA unit may only see 30% to 50% operating
hours, which will cut the annual savings and prolong the
payback period.
There are other things that can be done to reduce
energy usage including:
• Reducing operating time (don’t run it unless you
have to).
• Considering demand control ventilation or some
other means of reducing the supply airflow when pos-
sible. This improves the value of the direct drive plenum
fans with VFDs.
• Use low leakage outdoor air dampers to reduce
infiltration when the unit is off. In very cold climates
consider insulated low leak dampers.
• Consider face and bypass DX coil arrangements to re-
duce the condensing unit size (this requires expanding the
RH comfort criteria). This will cut the cooling load in half
reducing the first cost and operating cost. It will also avoid
the need for any reheat; however, dehumidification will be
reduced. In many applications this may be acceptable.
• Evaporative cooling (depending on location).
• Single air path (reheat) or dual air path energy
recovery. A dual air path energy recovery unit can offer
substantial savings however at a higher first cost for
both the unit and the return air ducting work. ASHRAE
Standard 90.1 has requirements for exhaust air energy
recovery depending on location and application. The
proposed energy savings outlined in this article would
also apply to an energy recovery MUA unit.
References1. ANSI Z83.8/CSA 2.6 -2013, Standard for Gas Unit Heaters, Gas Pack-
aged Heaters, Gas Utility Heaters and Gas-Fired Duct Furnaces.2. ANSI/ASHRAE/IES Standard 90.1 -2013, Energy Standard For
Buildings Except Low-Rise Residential Buildings.3. Natural Gas and Electricity rates are based 2013 U.S. Energy
Information Administration.4. ANSI/ASHRAE/USGBC/IES Standard 189.1 -2009, Standard for
the Design of High Performance Green Buildings. Table 7.5.3. 5. Crowther, H. 2014. “Air Leakage in Air Handling Units.” Price
Industries White Paper.
TECHNICAL FEATURE
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 53 4
TECHNICAL FEATURE | Fundamentals at Work
Kwang Woo Kim, Arch.D., is a professor of architecture at Seoul National University, Seoul, South Korea, and president of Architectural Institute of Korea. Bjarne W. Olesen, Ph.D., is director, professor, International Centre for Indoor Environment and Energy, Technical University of Denmark in Lyngby, Denmark, and vice president of ASHRAE.
The control of radiant heating and cooling system can
be classified as central control, zone control and individ-
ual room control. Figure 1 is a diagram on the principles
of control.
The central control controls the supply water tempera-
ture for the radiant system based on the outside tem-
perature. The room control then controls the water flow
rate or water temperature for each room according to
the room setpoint temperature.
Instead of controlling the supply water tempera-
ture, it is recommended to control the average water
temperature (mean value of supply and return water
temperature) according to outside and/or indoor tem-
peratures. During the heating period, as the internal
load increases, the heat output from the radiant system
will decrease and the return temperature will rise. If the
control system controls the average water temperature,
Control of the of the of heating and heating and heating cooling system cooling system cooling needs to be able to maintain the indoortemperatures within the comfort range under the varying internal varying internal varying loads and exter-nal climates. To maintain a stable thermal environment, the control system needsto maintain the balance between the heat gain/loss of the of the of building and building and building the suppliedenergy fromenergy fromenergy the system. Several studies in the literature deal with control.1–4
the supply water temperature will automatically
decrease due to the increased return water temperature.
This will result in a faster and more accurate control
of the thermal output to the space and will give better
energy performance than controlling the supply water
temperature.
Radiant surface cooling systems need controls to avoid
condensation. This can be done by a central control of
the supply water temperature limiting the minimum
water temperature based on the zone with the highest
dew-point temperature. If the supply water tempera-
ture is limited, the temperature of the rest of system
will be higher than the dew point, and there is no risk
of condensation on the pipes, and on the surface of the
radiant system. Limiting the supply water temperature
will lower the cooling power of a radiant system at high
indoor humidity levels. Dehumidifying the ventilation
BY KWANG WOO KIM, ARCH.D., MEMBER ASHRAE; BJARNE W. OLESEN, PH.D., FELLOW ASHRAE
Radiant Heating and Heating and HeatingCooling SystemsCooling SystemsCooling
Part TwoPart TwoPart
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 3 5
TECHNICAL FEATURE
air will result in lower dew-point temperature and will
allow higher cooling capacity of a radiant system.
Larger buildings should be divided in several different
thermal zones to optimize energy and control perfor-
mance. Each zone can be controlled with reference to
a temperature sensor in a representative space of the
zone.
For the improved comfort and further energy savings,
use an individual room temperature control. Each valve
on the manifold is controlled by each room thermo-
stat. An apartment or one-family house normally was
regarded as one zone, but installing thermostats for each
room is becoming popular. For better thermal comfort,
it is preferable to control the room temperature as a
function of the operative temperature.6
The heat capacity of surfaces with embedded pipes
plays a significant role for the thermodynamic proper-
ties of the heating system and, hence, for the control
strategy. An obvious consequence of the response time
of a conventional floor structures is that the instant
control of the heating power is not necessary. The tem-
perature of heat transfer medium, the time response
and the thermal capacity of systems depends on the
thickness of the surface layer where the pipes are
embedded.
For a low-temperature heating and high-temper-
ature cooling system, a significant effect is the “self-
regulating” control. This “self-regulating” depends
partly on the temperature difference between room
and heated/cooled surface, and partly on the differ-
ence between room and the average water tempera-
ture in the embedded pipes. This impact is bigger
for systems with surface temperatures close to room
temperature because the small temperature change
represents a higher percentage compared to the same
temperature change at a high temperature differ-
ence. The self-regulating effect supports the control
equipment in maintaining a stable thermal environ-
ment, and providing comfort to the persons in the
room.
For TABS, the concrete slab can be controlled at a
near constant core (water) temperature year-round.
Therefore, zone control (south-north), rather than indi-
vidual room control is more appropriate, because zone
level supply water temperature, average water tempera-
ture or flow rate control would be possible. Relatively
small temperature differences between the heated or
cooled surface and the space would result in a signifi-
cant degree of self-control.
As a TABS is not removing the room load imme-
diately, the control cannot keep a constant room
temperature during the day. Instead, a small room
temperature drift will result. An example from a
simulation is shown in Figure 2. The figure is compa-
rable with Figure 8 of Part 1 showing the energy flows.
Water of 20°C (68°F) is circulating in the concrete
slab from 6 p.m. to 8 a.m. the next morning. It can be
seen that the room is kept within the comfort range
of –0.5<PMV<+0.5. The operative temperature runs
between the line for air temperature and mean radi-
ant temperature and is within the comfort range of
23°C to 26°C (73.4°F to 78.8°F). This is an example on
how a dynamic building simulation may be used to
verify that by the used water temperatures or given
B = Boiler OTS = Outside Temperature SensorC = Chiller P = PumpCU = Control Unit RS = Room SensorPTS = Panel Temperature Sensor RTS = Return Medium Temperature SensorL = Limiter SOV = Shut Off ValveM = Manifold STS = Supply Medium Temperature SensorMC = Main Controller THS = Temperature-Humidity SensorMV = Mixing Valve
Figure
FigureRS
CU
M
PTS THS
B
RTS L STS
MC
C
MV
SOV
SOV
P OTS
FIGURE 1 Principal diagram of an embedded radiant heating and cooling system exemplified by a radiant floor system.5
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 53 6
chiller capacity the room will be
kept within the comfort range.
The objectives for the most eco-
nomic operation and operation
strategies of the building system
are the minimum total energy
costs and the minimum peak
electricity demand. As the radiant
system only can take care of sen-
sible heat load, the system needs to
be operated in combination with
air systems for ventilation, dehu-
midification and additional ther-
mal requirements. Therefore, the
system designer should consider TABS, the temperature variation of the water is very
small and the lifetime of the pipes are more than 100
years.
All couplings within the embedded construction
should be exactly located and designated on the record
drawing. The bending radius shall not be less than the
minimum bending radius defined in the relevant prod-
uct standards.
The thickness of the screed layer should be cal-
culated according to carrying capacity specified in
national codes. The screed thickness above pipes
must be at least 30 mm (1.2 in.). The temperature of
the liquid screed and the room should not be lower
than 5°C (41°F) for at least three days. Hardening
screed should be protected from draft, fast drying and
harmful effects.
Initial heating should be carried out in accordance
with the manufacturer’s instructions, but should be
maintained for at least seven days for systems with
anhydrite screeds. This operation commences at a sup-
ply temperature of between 20°C and 25°C (68°F and
77°F), which should be maintained for at least three
days. Subsequently, the maximum design temperature
should be imposed. The process of heating up must be
documented.
The thickness of the concrete for TABS should be cal-
culated according to load-bearing capacity specified
in national codes, and the position of pipes should be
considered in the gravity load calculation of the slab.
Pipes are commonly installed in the center of the con-
crete slab between the reinforcements. If the system is
constructed on site, the pipes are supplied in modules,
more energy-efficient HVAC systems and use of
renewable energy sources.
Another possible strategy is to reduce “room side”
energy demand. The room temperature control strategy
allowing a little fluctuation may bring significant energy
savings in comparison with keeping constant room tem-
peratures. Temperature fluctuations of up to 3 to 4K (5°F
to 7°F) per hour will not cause any additional comfort
problems as long as the room temperature is within the
specified comfort zone.
Installation For the installation of systems embedded in floor,
wall or ceiling, the manufacturer’s instructions must
be followed. To limit the heat flow toward the outside
(not exceed 10% of total heat flow) or to adjacent spaces,
a minimum thermal resistance of the insulating layer
shall be specified in the design. The effective thickness
of the insulating layer depends on the construction of
the radiant system. The thermal conditions under the
floor structure should be considered for an embedded
floor heating system insulation.
The dimensions of pipes must comply with the
requirements of the Standards. Minimal pipe thick-
ness should comply with the requirements for service
conditions, operation pressure (higher than 4 bar
[1,600 in. w.g.]) and durability (more than 50 years).
The use of plastic pipes with an oxygen-barrier layer is
recommended to reduce corrosion problems. However,
the risk for oxygen penetration is highest at very high
water temperatures, which you do not find in modern
buildings. For pipes embedded in concrete such as
FIGURE 2 Example of the temperature changes during a day in a space with TABS.
T Floor T mr T air
PMV
T ceiling
T water return
°F °C86.0 30
84.2 29
82.4 28
80.6 27
78.8 26
77.0 25
75.2 24
73.4 23
71.6 22
69.8 21
68.0 20
1
0.5
0
–0.5
–1
Pred
icted
Mea
n Vo
te
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0
TECHNICAL FEATURE | Fundamentals at Work
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M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 3 7
which include a pipe coil attached
to the metal grid and equipped with
fittings.
Prior to embedding in screed or
concrete, the pipe circuits should
be checked for leaks by means of a
water pressure test. The test pres-
sure should be twice the working
pressure with a minimum of 6 bar
(2,400 in. w.g.). Where danger of
freezing water occurs during winter
installation, air can be used instead.
During the laying of the screed, this
pressure should be applied to the
pipes.
For TABS, the pipes are installed
during the main construction of
the building. This requires that the
decision on which heating-cooling
system to use must be made at an
early stage. It is also important that
the installation of the pipes do not
prolong the building construction
and costs. Therefore it is today pos-
sible to use prefabricated concrete
slabs with pipes embedded from the
producer’s side. For in-situ casting
of the concrete, it is recommended
to supply the pipes premounted on
mesh-like modules.
Applications Embedded surface systems are
used for heating and cooling in vari-
ous types of buildings. Principally,
ceiling systems are used as supple-
mentary air-conditioning systems
in non-residential office buildings.
The system can work with a quite
high cooling capacity of 50 to 100
W/m2 (16 to 32 Btu/h·ft²) limited by
the risk of condensation. Ceiling
heating is limited by standard
requirements for radiant asymme-
try to a capacity of 40 to 50 W/m2 (13
to 16 Btu/h·ft²) depending on ceil-
ing height. Floor and wall heating
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 53 8
systems are popular for residential
buildings, mostly in single family
houses and apartments because of
extra space created by embedding
the pipes in structure. The system
is suitable for spaces with heat-
ing loads of 10 to 100 W/m² (3 to 32
Btu/h·ft²) and cooling loads of 10
to 40 W/m² (3 to 13 Btu/h·ft²). The
warm surface is comfortable for
children playing on the floor. The
absence of radiators avoids injury in
rooms occupied by the elderly and
children.
Wall systems may limit furnish-
ing possibilities and the mounting
of wall pictures. Floor cooling sys-
tems in spaces that are influenced
by direct sunlight may rarely reach
a short-time cooling capacity of
more than 100 W/m² (32 Btu/h·ft²) if
unshaded and directly exposed.
Floor heating of high spaces
(large industrial building,
churches, etc.) ensures uniform
thermal conditioning and tem-
perature profiles in the occupied
space. The accumulated heat in
the floor of an aircraft hangar can
warm it up again in a half hour
after the aircraft moves out and
the doors closed. The system with
a heat conductive device or with
micro pipes requires a thin floor
construction, and can be used for
the renovation of buildings, as well
as for lightweight structure (e.g.,
wooden) buildings. In lightweight
building structures with a lack
of thermal mass, the installation
of TABS with PCM can be a solu-
tion. A PCM panel of 50 mm (2 in.)
thickness is able to store the same
amount of energy as a 250 mm
(10 in.) thick concrete slab. TABS
are usually installed into the ceil-
ing concrete slabs of multi-story
non-residential buildings. There
are also known application for
hospitals, museums, show rooms,
schools and libraries. TABS is suit-
able for buildings with cooling
loads up to 40 to 60 W/m² (13 to 19
Btu/h·ft²). In buildings with loads
over 60W/m² (19 Btu/h·ft²) the
installation of a complementary
convective system for cooling is
recommended in case of fast load
changes.
TABS is not fully suitable for instal-
lation as the only thermal condi-
tioning system in family houses,
as the user may want to reduce the
temperature level in sleeping rooms
during the daytime, when the room
is unoccupied. In that case an addi-
tional system for individual control
is required.
Examples of ApplicationsExamples of buildings in Canada
with embedded radiant heating and
cooling systems include:
• ICT Building at the University of
Calgary
• Gleneagles Community Centre,
West Vancouver, BC
• Kortwright Conservation Cen-
tre (Earth Rangers)
• Simon Fraser University Resi-
dences
• MacLeod II ECE Building (Fred
Kaiser Building) at the University of
British Columbia
• Manitoba Hydro Headquarters,
Winnipeg Manitoba
• Vancouver General Hospital
Cancer Research Centre
• Irving K. Barber Learning Cen-
tre, UBC
• City of North Vancouver Main
Library
Examples of buildings with a com-
bination of TABS and ground source
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 3 9
1
1 = Active Slab With Pipes 2 = Fresh Air Supply with Local Heating-Up3 = Air Exhaust and Cable Channel Above 4 = Lighting5 = Sun Screening/Shading 6 = Photovoltaic
FIGURE 4 Heat exchange and airflow pattern during cooling operation.7
6
6
6
5
5
2
2
4
4
1 3
31
mm
FIGURE 3 Typical temperature distribution in the floor/ceiling during cooling mode. 1 = linoleum, screed, wood plates, trapped air layer, concrete slab.
515
40
180
20
300
14023.2°C (73.8°F)
26°C (78.8°F)
18.3°C (64.9°F)
20.1°C (68.2°F)
20.9°C (69.6°F)21.3°C (70.3°F)
24.5°C (76.1°F)
heat pumps have been collected in an European project
(GEOTABS, http://www.geotabs.eu/Database).
Office Building in GermanyA 6,500 m² (70,000 ft²) and five-story annex build-
ing of an office in Stuttgart, Germany is installed
with thermally active building system (TABS) and a
mechanical ventilation system. The construction of the
slab is shown in Figure 3. The heat carrier circulates in
meandering pipe circuits (VPE pipes, 20 mm [0.8 in.]
diameter) embedded into the load-bearing 300 mm (12
in.) concrete ceiling. Piping material (VPE instead of
common PE-X) was chosen in accordance with higher
load strain of the slab due to the 15 m (49 ft) distance
between the columns. Total length of piping is about
49,000 m (160,000 ft) at 9,750 m² (105,000 ft²) of active
ceiling area.
The trapped air layer of 180 mm (7 in.) significantly
influences the heat conduction in the slab upwards
and the radiated heat released from the floor surface
(Figure 3). The air gap space is used for installation of IT
and electricity cables, water distribution and air duct
system.
Figure 4 shows the summer conditions of heat
exchange and room airflows. TABS is associated with
the air-conditioning system using 100% fresh air sup-
plied by plinth units (close to the façade), and floor
inlet units (building core area). The system controls the
individual room humidity and covers a percentage of
the peak loads (cooling ~10%, heating ~18%). The fresh
air inlet units provide 80 to 100 m3/h per person (47 to
59 cfm/person) corresponding to about 45 m³/h (26.5
cfm) and 1.57 ach. The air velocity is less than 0.11 m/s
(21.7 fpm) in 0.6 m (2 ft) distance from the inlet units
and the relative humidity varies between 45−60% (for
closed windows).
The mean water temperature in the activated slabs
is controlled according to outdoor temperature year
round. The actual supply water temperature varies
between 19°C to 23°C (66.2°F to 73.4°F). Using this
strategy, in conjunction with the ventilation system,
the room temperatures are maintained between 22°C
to 26°C (71.6°F to 78.8°F) in summer and 21°C to 24°C
(69.8°F to 75.2°F) in winter.
As the heat carrier in summer circulates only dur-
ing the night, power demand is greater during the
night time and takes advantage of the cheaper elec-
tricity night tariff. The field measurements result
showed operative temperature during working hours
were kept between 22°C to 25°C (71.6°F and 77°F) in
summer and 21°C to 23°C (69.8°F to 73.4°F) in winter
(Figure 5).8
TECHNICAL FEATURE
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 54 0
High-Rise Apartment Building in Korea In Korea, 100% of residential buildings are
heated with radiant floor heating systems.
Even the 300 m (984 ft) high, 80 story high-
rise residential apartment building “We’ve
the Zenith” (Figure 6), is heated with a radiant
floor heating system. Hot water is gener-
ated by boilers in rooftop mechanical room,
and serves seven vertical heating zones with
proper hot water temperature for radiant
floor heating after heat exchange.
University Building in KoreaEwha Womans University Campus Center
(ECC) in Seoul, Korea, is a good example of
non-residential building application (Figure
7). It is a university complex including lec-
ture rooms, offices and public spaces. ECC
is designed by Dominique Perrault and local
Baum Architects.
Accumulated energy in massive ceilings
is used by means of concrete core activa-
tion to reduce energy demand for thermal
well-being. The cooling with the concrete
core activation is done by chilled water tem-
peratures of 17°C (62.6°F) supply and 20°C
(68°F) return, and heating by hot water tem-
peratures of 29°C (84.2°F) supply and 26°C
(78.8°F) return.
The first step of the cooling is done by
the remaining cool energy of the return-
ing water to absorption chiller. The second
step is to use stored energy of the ground-
water storage tanks. The third step is to use
earth energy through the pipes under the
basement floor. The cooling energy for the
concrete core activation is supplied con-
tinuously over 24 hours, therefore, there is
no peak load and the sizes of all necessary
equipment could be reduced to a minimum.
Airport in BangkokThe international airport Bangkok, which
opened in September 2006, is thermally con-
ditioned by a floor surface cooling system in
combination with a displacement ventilation
system (Figure 8). Its 150 000 m² (1.6 milion
FIGURE 5 Sample of operative temperatures measured during a work week in an office building equipped with TABS. A = 4th floor east; B = 4th floor south; C = 5th floor east; D = 5th floor west; E = outside temperature.8
0 12 24 12 24 12 24 12 24 12 24
75.2
73.4
71.6
69.8
68.0
66.2
24
23
22
21
20
19
°F°C Heating Season (Winter)
Cooling Season (Summer)95.0
91.4
80.6
73.4
66.2
59.0
35
33
27
23
19
15
°F°C
0 12 24 12 24 12 24 12 24 12 24
A B C D E
FIGURE 6 High-rise apartment building, ‘We’ve the Zenith,’ with radiant floor heating system (Busan, South Korea). Left: Exterior view; Right: Mechanical system diagram of radiant system.
Compact HeatExchanger
B1 Floor Mechanical Room
HWS: 115°C (239°F)
HWR: 75°C (167°F)
HX HX
HX HX
HX HX
HX
HX
HX
HWS: 80°C (176°F)
HWR: 65°C (149°F)
HWS: 65°C (149°F)
HWR: 40°C (104°F)
31st FloorMechanical Room
59th Floor Mechanical Room
HWS: 65°C (149°F)
HWR: 40°C (104°F)
HWS: 65°C (149°F)
HWR: 40°C (104°F)
Rooftop Mechanical Room
TECHNICAL FEATURE | Fundamentals at Work
C E I L I N G G R I D S Y S T E M
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To provide both cool-
ing and ventilation, two
separate systems are com-
bined. The under-floor
cooling system directly
absorbs the solar gains
whilst maintaining a com-
fortable floor surface tem-
perature (minimum 21°C
[70oF]). The displacement
ventilation system with
a variable flow volume
provides dehumidified
fresh and re-circulated
air at floor level via an
approximately 2 m (6ft, 8
in.) high air diffuser. Due
to the warm climate the
temperature in winter
may achieve in average of
control performance of hydronic radiant heating systems based on the emulation using hardware-in-the-loop simulation”, Building and Environment 46(10).
3. Kang, D.H., et al. 2010. “Effect of MRT variation on the energy consumption in a PMV-controlled office.” Building and Environment 45:1914-1922. 2010.9.
4. Rhee, K.N., Ryu, S.R., Yeo, M.S., Kim, K.W. 2010. “Simulation study on hydronic balancing to improve individual room control for radiant floor heating system.” Building Services Engineering Research and Technology 31(1):57–73.
5. ISO 11855-6: 2012. Building environment design - Design, dimension-ing, installation and control of the embedded radiant heating and cooling systems – Part 6: Control.
6. Olesen, B.W. 1997. “Possibilities and limitations of radiant floor cooling.” ASHRAE Transactions 103(1):42–48.
7. Wiercioch, H. 2001. Betriebserfahrung mit Betonkernaktivier-ung, BV M+W Zander Stuttgart, In proc: 23.Velta kongress 2001, Wirsbo-Velta, Nordestedt, Germany.
8. De Carli, M., Olesen, B.W. 2001. “Field measurement of thermal comfort conditions in building with radiant surface cooling sys-tem.” Clima 2000.
FIGURE 7 ECC with TABS and radiant ceiling panel (Seoul, South Korea). Left: Exterior view of ECC; Right: Radiant ceiling panels.
FIGURE 8 Bangkok Airport (Bangkok, Thailand). Top Left: Concourse building shell; Top Right: Interior membrane; Bottom Left: Installation of floor cooling: Bottom Right: Boundary conditions and simulated temperatures in the concourse, 20°C (68°F) Blue; 30°C (86°F) Deep Green; 40°C (104°F) Red.1
ft²) of cooled floor area, comparable
to 20 football fields, is recognized as
the world’s largest application. With
the length of 440 m (1,440 ft) and a
width of 110 m (360 ft) and an area of
almost 500 000 m² (5.2 million ft²)
the terminal became the largest com-
bined building complex of its kind in
the world. The H-shaped concourses
have a total length of 3.5 km (2.2
miles).
21°C (70°F) during the night (summer 25°C [77°F]) and
31°C (88°F) during the day (summer 34°C [93°F]). The
solar radiation usually incidents perpendicularly to the
earth’s surface and reaches the level up to 1,000 W/m²
(300 Btu/ h·ft²). Due to the narrow range of the operative
temperature at 24°C (75°F) and a relative humidity of
between 50 and 60% during the 24 opening period the
airport requires constant cooling and dehumidification.
AcknowledgmentsThis article was supported by VELUX guest professorship, and a grant from the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. 2014-050381).
References1. Olesen, B.W. 2001. “Control of floor heating and cooling sys-
tems.” Clima 2000/Napoli 2001 World Congress.2. Rhee, K.N., Yeo, Myoung S., Kim, K.W. 2011. “Evaluation of the
TECHNICAL FEATURE | Fundamentals at Work
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 54 4
COLUMN ENGINEER’S NOTEBOOK
Steven T. Taylor
Return AirReturn AirReturn Systems Air Systems Air
Steven T. Taylor, P.E., is a principal of Taylor Engineering in Alameda, Calif. He is a mem-ber of SSPC 90.1 and chair of TC 4.3, Ventilation Requirements and Infiltration.
BY STEVEN T. TAYLOR, P.E., FELLOW ASHRAE
or relief fans in lieu of less efficient return fans, which
are generally required when return air is fully ducted.1,2
• Little or no balancing costs for the return air system
and, for VAV systems, balance is better maintained as
supply airflow rate varies as loads vary. Ducted return
systems can only be balanced at one condition, generally
at design airflow rates, and are inherently unbalanced
at other conditions, possibly leading to overly positive or
negative space pressurization.
• Reduced noise transfer between rooms. Sheet metal
ducts, if unlined, are very adept at channeling crosstalk
from room to room,* much more so than a large ceiling
plenum where noise can dissipate.
Disadvantages of Architectural Return Air PlenumsOn the other hand, using architectural plenums has
some potential disadvantages:
• There is the possibility of indoor air quality prob-
lems in humid climates if the architectural plenum is
negatively pressurized to the outdoors.3 Humid out-
door air can be drawn into the architectural plenum
and cooled below the dew point, causing condensation
and subsequent mold and mildew problems within the
structure. This potential problem can be avoided by sim-
ply not allowing the architectural plenums to become
negatively pressurized relative to outdoors. For example,
a return air plenum can be easily designed and con-
trolled to be positively pressured. First, the building can
be controlled to be pressurized to about 0.05 in. w.c.
(12.5 Pa),4 and ceiling return air grilles can be selected
to have a pressure drop of only about 0.02 in. w.c. (5 Pa).
The ceiling plenum will thus be positive 0.03 in.w.c. (7.5
Most HVAC systems at least partially recirculate partially recirculate partially air to increase cooling or cooling or cooling heatingcapacity tocapacity tocapacity conditioned spaces while avoiding the avoiding the avoiding energy and energy and energy first cost impact ofconditioning outdoorconditioning outdoorconditioning air. These systems generally take generally take generally one of the of the of following forms: following forms: following
• Return air is conveyed entirely in ductwork from
the conditioned space back to the air-handling unit;
• Return air is conveyed entirely using architectural
plenums such as ceiling cavities, drywall shafts, and
mechanical rooms; or
• A combination of ductwork and architectural ple-
nums.
Using architectural plenums is prohibited in some
applications. For instance, most model mechanical
codes do not allow conveying air in plenums exposed
to materials that do not meet certain flame spread and
smoke generation limits, such as wood beams or trusses.
Most health-care codes also prohibit the use of archi-
tectural plenums for critical medical spaces because of
concern about asepsis. But for most commercial and
residential applications, architectural plenums can be
used.
Benefits of Architectural Return Air PlenumsThe benefits of using architectural plenums vs. duct-
work include:
• Reduced HVAC system costs of about $3 to $5 per
square foot ($32 to $54 per square meter), about 10% to
20% of the total HVAC system cost.
• Reduced costs to other trades to accommodate the
congestion caused by the added return air ductwork,
such as raising the floor-to-floor height or adding ad-
ditional offsets in plumbing and sprinkler piping.
• Reduced fan energy costs of about 20% to 30% due
to the much lower pressure drop of the plenum return
system.
• Reduced fan energy in systems with outdoor air
economizers due to the ability to use non-powered relief *The author experienced this firsthand with a home that was custom built for the previous owner who required that the furnace be fully ducted to each room with unlined sheet metal ducts. My teenage children entertained themselves for hours spying on each other by listening through the return air grilles. The first modification my wife and I made to the house was to blank off the return air grille to our bedroom…
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 4 5
COLUMN ENGINEER’S NOTEBOOK
Pa) relative to the outdoors (Figure 1; note that all pres-
sures shown are relative to outdoors). Of course, wind
pressure and stack effect can overwhelm these small-
positive pressures, but that is true of both plenum and
ducted return air systems.
• Figure 1 shows that while the ceiling return air
plenum is positive to the outdoors, the shaft is not. It is
generally not practical for the shaft to be designed to be
positive to the outdoors without overpressurizing the
space. In humid climates, it is critical that the architec-
tural return shaft be completely disconnected from the
exterior walls; if the structure is built so this negative
pressure is seen at the exterior wall, moisture and
mold problems can result. This disconnect is generally
not an issue for steel and concrete structures, but may
be for wood construction typical of residential build-
ings. In the latter case, ducting the return air riser
(Figure 2a) is a good idea versus unducted (Figure 2b). It
may also be required by code if the return air system
is being used for smoke exhaust such as in a high-rise
building. But many engineers duct the return air riser
even when leakage into the riser is simply return air
from the conditioned space, not from the outdoors.
Shaft leakage does not matter in this case – the air
leaked into the shaft is the same air that is drawn into
the return air duct. Ducting the riser in this case adds
to first costs, energy costs, and space requirements
and can cause imbalances in airflow between floors as
supply air and return air rates vary in VAV systems. If
the shaft is unducted and sized for low velocity (less
than 1000 fpm [5 m/s] through the free area at the top
of the shaft), airflow pressure drop from top to bottom
is small, making the shaft nearly self-balancing. Again,
stack effect may also cause imbalances, but that is true
both ducted and unducted risers.
• Some indoor air quality specialists point out that
even dry architectural plenums can be potential sources
of indoor air quality pollutants such as particles. A ceil-
ing return air plenum that has been used for a few years
could have substantial dust accumulation on plenum
surfaces. But return air ducts could have a similar or
even thicker layer of dust. The dust “challenge” for both
are particles drawn from the conditioned space and the
source strength of these particles is the same whether
the return air is ducted or an architectural plenum.
In both cases, the air will be filtered at the air handler
before the recirculated air is supplied to the space, so in
both cases, this is generally a non-issue from an indoor
air quality perspective. Particle challenges from outdoor
ventilation air are usually much greater.
• It is common for full height (slab-to-slab) walls to
be provided as acoustical barriers for noise sensitive
spaces, such as conference rooms. An acoustic return air
transfer “boot” must be provided at these spaces to allow
return air to transfer from them to the ceiling plenum
or to the adjacent space. Figure 3 shows an inexpensive
sound boot: it is composed of a standard 5 ft (1.5 m) duct
section that can be produced from a typical “coil line”
duct making machine, which reduces its cost relative to
a hand fabricated zee-shaped duct or elbow although
acoustic performance of the latter may be better. Rules
of thumb for sizing various return air transfer assem-
blies are shown in Table 1.
• Maintaining a low pressure drop return air path from
conditioned spaces to the air handler can be a challenge
using architectural plenums when spaces are divided by
FIGURE 1 Typical pressures: Plenum return.
–0.02 R.A. Ceiling Plenum +0.03 in.–0.05
R.A. S
haft
+0.05
FIGURE 2 Return air risers.
Ducted UnductedA. B.
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 54 6
many floor-to-floor partitions, such as acoustical parti-
tions, tenant separation walls, and rated corridor walls.
Where there are multiple partitions between the air
handler or return air shaft and the most remote rooms,
return air transfer openings and sound boots must be sized
for even lower velocities and get progressively larger (Figure
4) to ensure that the overall pressure drop remains low to
FIGURE 3 Inexpensive return air sound boot. TABLE 1 Rule-of-thumb design velocities for transfer assemblies.
NO.INLET
LOCATIONDISCHARGE
LOCATIONAPPLICATION
DUCT S IZ ING RULE OF THUMB
FPM
1 Return Air Plenum
Return Air Plenum
Lined 5 ft Boot (Figure 3) 800
2 Return Air Plenum
Return Air Plenum Flex Duct Both Sides 750
3 Return Air Plenum
Return Air Plenum
Single Elbow (No Turning Vanes) 700
4 Return Air Plenum
Return Air Plenum
Double Elbow Both Sides (No Turning Vanes) 575
5 Ceiling Grille Return Air Plenum
Flex Duct to Perforated Face Grille 500
6 Ceiling Grille Ceiling Grille Flex Duct to Perforated Face Grilles 350
7 Return Air Plenum Ceiling Grille Toilet Makeup.
Flex Duct to Perforated Face 325
The velocities are intended to result in a 0.08 in.w.c. (20 Pa) pressure drop across the transfer as-sembly including pressure drop of entrance, exit, duct, and grilles. Return air plenum is assumed to be 0.02 in. w.c. (5 Pa) relative to the space for Application 5 and 0.05 in. w.c. (12 Pa) for Application 7. Note that these are for a single return air transfer – for multiple boots in series (e.g., cascading from one room to another before it gets to the shaft), velocities must be even lower so the total pressure drop does not exceed 0.08 in. from furthest room to shaft or fan room to ensure exterior plenum walls are positively pressurized relative to the outdoors.
WallWall
Lined Transfer Boot
COLUMN ENGINEER’S NOTEBOOK
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 4 7
avoid negative plenum pressures relative to the outdoors
around the building perimeter. There are applications
where this necessitates such large return air boots that
ducting the return air may be the right choice. But this is
seldom or never true when the ceiling is not divided by full
height walls. Many engineers partially duct return air into
ceiling plenums to “within no more than 30 ft” (or other
rule-of-thumb) of return air grilles believing that this
improves return air performance. In the author’s opinion,
there is no value to these duct extensions and they add to
first costs and energy costs. If there is room in the ceiling
for the return air duct, there is even more room in the
return air plenum without the duct, so velocity and pres-
sure drop will be lower if the duct is eliminated.
Diagnosing Return Air ProblemsA common misdiagnosis is that a room is undercooled
“because it has no return air path—the air is trapped.”
However, this is almost never the case with ducted sup-
ply air systems such as VAV systems. This is because
the walls and ceiling enclosing a typical room are not
so airtight that they can cause enough backpressure to
prevent air from the supply air fan from being supplied
to the room.† If supply airflow to a room is verified by
a flow hood, VAV box airflow sensor, or other airflow
measuring device, the room is being conditioned even if
there is no obvious return air path; air is simply leaving
the room through leaks in walls, ceilings, doors, etc. To
verify this, simply compare the measured supply airflow
rate with the doors to the room open and then closed.
So a constricted return air path will seldom cause tem-
perature control problems. But they can create differen-
tial pressure problems resulting in doors being pushed
closed or open and audible airflow noise at leakage
points such as around doors.
If the air handler has an airside economizer, these
same symptoms can also be caused by an ineffective
relief air path, such as an undersized non-powered
relief (barometric) damper or undersized relief fan
(powered exhaust). To determine which path, return or
relief, is the cause, perform this simple test:
1. Configure the economizer dampers for zero outdoor
air, zero exhaust air, and 100% return air.
2. If the system has a relief fan, turn it off. If it has a
return fan that is controlled by airflow tracking,4 control
† This rule is generally not true of low pressure unducted systems such as underfloor air distribution (UFAD) systems. The floor pressure is generally very low, less than 0.1 in. w.c. (25 Pa), so backpressure caused by a restricted return air path from a room can restrict supply airflow and thus cause temperature control problems.
the fan with zero offset. If the return fan has direct
building pressure control, disable this control so the
relief damper is closed.
3. Open VAV boxes as required to simulate full design
conditions.
4. Run the supply air fan under normal control.
If the building or room pressures are excessive during
this test, the return air path is constricted. If not, the
relief system is the source of the problem. This could be
verified by configuring the system in 100% outdoor air,
100% exhaust mode.
Once the constricted path is identified, the pinch point
or points can be identified by measuring static pressure
along the path looking for excessive pressure drops.
Conclusions and RecommendationsThe benefits of using architectural plenums for return
air are substantial, including much lower first costs and
lower energy costs. In most cases, the design is also easy:
just ensure that each space has a low pressure return air
path back to the air handler. But where there are many
full height walls and other constrictions, care must be
taken to ensure that the low velocity return air path is
maintained by properly sizing transfer ducts and sound
boots.
References1. Taylor, S. 2000. “Comparing economizer relief systems.”
ASHRAE Journal (9).2. Kettler, J. 2004. “Return fans or relief fans.” ASHRAE Journal (4). 3. Lstiburek, J. 2009. “Fundamental changes in the last 50 years.”
ASHRAE Journal (7).4. Taylor, S. 2014. “Controlling return air fans in VAV systems.”
ASHRAE Journal (10).
FIGURE 4 Return air boots in series.
–0.03 in. +0.03 in.–0.02 –0.05
R.A. S
haft
+0.05
+0.00 in.
COLUMN ENGINEER’S NOTEBOOK
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 54 8
COLUMN BUILDING SCIENCES
Joseph W. Lstiburek
BY JOSEPH W. LSTIBUREK, PH.D., P.ENG., FELLOW ASHRAE
Things have evolved considerably evolved considerably evolved since considerably since considerablythe Eisenhower and Eisenhower and Eisenhower Diefenbaker and Diefenbaker and years. Diefenbaker years. DiefenbakerHutcheon† taught us about airflow that airflow that airflowdecade but it took more took more took than a half century half century halfto get it right. We needed air needed air needed control. air control. air Weneeded anneeded anneeded air an air an control air control air layer control layer control – layer – layer an – an – air an air an barrier. air barrier. airWe started off started off started with off with off locating with locating with it locating it locating on it on it the on the on insideand finallyand finallyand ended finally ended finally up ended up ended with it with it with on it on it the on the on outside.‡
We started by started by started combining by combining by it combining it combining with it with it a with a with vapor a vapor abarrier onbarrier onbarrier the on the on inside then we then we then finished by finished by finishedcombining itcombining itcombining with it with it a with a with weather a weather a resistive weather resistive weather barrier(WRB) and continuous and continuous and insulation on insulation on insulation the on the onoutside (Figures (Figures ( 1Figures 1Figures through 5)through 5)through .
Throughout the postwar years practitioners were
taught, incorrectly, that vapor barriers were necessary in
cold climates to protect wall assemblies from moisture
damage and that it was necessary to install these vapor
barriers on the interior of cavity insulation. The industry
saw the introduction of kraft facings and foil facings on
batt insulations as a result. These vapor barriers were by
their very nature discontinuous and they proved inef-
fective in protecting wall assemblies from vapor. Vapor
is principally transported by airflow not by vapor diffu-
sion. We needed air barriers not vapor barriers to con-
trol vapor flow. It took decades for that distinction to be
appreciated.§
Evolution of the Residential Air Barrier
Forty YearsForty YearsForty ofAir BarriersAir BarriersAir *
* This is a play on the title of Professor Hutcheon’s classic paper “Forty Years of Vapor Barriers.” Read down a couple of footnotes and enjoy….† Hutcheon, N.B.; “Fundamental Consideration in the Design of Exterior Walls for Building.” NRC Paper No. 3087, DBR No. 37. Division of Building Research, National Research Council of Canada, Ottawa, 1953.‡ At the turn of the 20th Century it became common to install a layer of rosin paper over wood board sheathing and under clapboard siding (see “The Evolution of Walls,” ASHRAE Journal, June 2009) to reduce drafts. This rosin paper was an early “air barrier.” Having pointed this out, I am going to conveniently ignore this fact because it messes with my narrative.§ “It was 30 years from the time of Rowley’s paper before it was clearly established and widely accepted that the leakage of air from inside a building through constructions, and not vapor diffusion alone, was often the principal means by which water vapor moved to cold surfaces. The concept of vapor diffusion was not wrong, but it was not the only way. It is incredible, in retrospect, that it should have taken so long to reach this conclusion….” N. B. Hutcheon, from “Forty Years of Vapor Barriers,” Canadian Consulting Engineer, special publication on Moisture Control, Ottawa, 1978.
PHOTO 1 Plastic Vapor Barrier. Not a “production friendly” method of achieving airtightness and it was not “robust” in terms of surviving the construction process and in providing performance over the service life of the building. It was also cli-mate sensitive. It made no sense for assemblies that saw air conditioning. It was a vapor barrier on the wrong side of such assemblies.
The first attempt at addressing the issue was to take
a vapor barrier material and turn it into an air bar-
rier. The result was coined an “air-vapor barrier.” Sheet
polyethylene was already being installed on the interior
of insulated wall assemblies as a vapor barrier (Photo
1). It was given a second function—that of air control.
Easy to do conceptually—very difficult to do in practice.
With painstaking effort and attention to detail, extraor-
dinary levels of airtightness were achieved using this
approach—less than 1 ach at 50 Pa. Canada’s R-2000
program was based on this approach. The sealant used
was “acoustical sealant” as it would remain flexible over
the service life of the building. It soon got the moniker
of “black death” as it got on to everything including the
installer. It became clear that the approach was not a
“production friendly” method of achieving airtightness
and it was not “robust” in terms of surviving the con-
struction process and in providing performance over the
service life of the building. It was also climate sensitive.
It made no sense for assemblies that saw air condition-
ing—it was a vapor barrier on the wrong side of an air-
conditioned wall (Figure 1).
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COLUMN BUILDING SCIENCES
Joseph W. Lstiburek, Ph.D., P.Eng., is a principal of Building Science Corporation in Westford, Mass. Visit www.buildingscience.com.
The next step in the evolution of the air barrier was the
“airtight drywall approach” (Figure 2)—where the interior
gypsum board lining became the air barrier (Photo 2). Sheet
polyethylene was no longer necessary. The approach was
more robust than polyethylene air-vapor barriers and since
gypsum board was not a vapor barrier the approach could
be used in any climate. However, to get to similar extraordi-
nary levels of airtightness as those being achieved with the
poly approach in the R-2000 program, painstaking effort
was still required. Most production builders concluded
such levels of airtightness were not worth the effort.
The focus shifted to targeting only the interior big
holes using sealed rigid draft-stopping. Bathtubs and
FIGURE 1 Polyethylene Air-Vapor Barrier. The period of “black death” where acoustical sealant that was black in color was used to seal overlapping sheets of 6 mil polyethylene to create a continuous air barrier. Note that where the mem-brane sheet wrapped the exterior rim joist it needed to be vapor open. Vapor open “housewraps” or plastic building papers were used in these locations.
FIGURE 2 The “Airtight Drywall Approach.”The interior gypsum board lining became the air barrier. The approach was more robust than polyethylene air-vapor barriers and since gypsum board was not a vapor barrier the approach could be used in any climate. However to get to similar extraordinary levels of airtightness painstaking effort was still required. PHOTO 2 Interior Gypsum Board as the Air Barrier. Note the sealant at the bottom plates and around window openings.
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 55 0
PHOTO 3 (LEFT) Bathtub on Exterior Wall. Targeting the big holes with rigid draft-stopping. Of course, an even better approach is not have a bathtub on an exterior wall. PHOTO 4 (R IGHT) One-Piece Tub Shower Enclosures. A really, really big hole on an exterior wall sealed by a very happy builder. Note the sealant around the perimeter of the rigid draft-stopping, sealing the draft-stopping to the framing.
FIGURE 3 Air Infiltration Barrier. Plastic housewraps were developed and had two functions: rainwater control and air control. PHOTO 5 Air Infiltration Barrier. Classic housewrap rainwater control layer and air control layer. Note the beautiful job of flashing integration with the housewrap. The outside is the right place for air control.
shower enclosures on exterior walls, fireplace assemblies
on exterior walls, soffits deadending in exterior walls,
dropped ceilings at enclosure perimeters, garage-to-house
connections and cantilevers (Photos 3 and 4). A “lite” version
“airtight drywall approach.” It became relatively easy for
production home builders to get below 3 ach at 50 Pa and
the approach morphed into the EPA Energy Star “thermal
bypass checklist” and eventually found its way into the
model codes.#
But getting to 1 ach at 50 Pa if you were a production
builder needed rethinking the problem. There were too
many problems with locating the air barrier on the interior.
Penetrations from electrical boxes, plumbing, intersecting
interior walls and intermediate floor framing made very
high levels of airtightness impossible for production home
builders with interior air barriers. The focus shifted to the
outside.
Why not turn the exterior building paper into the air
barrier? Tar paper was already being used for rainwater
control purposes. Why not turn it into an air barrier? Good
idea in principle, but tar paper was not the product up to
the task. You could not tape tar paper and it only came in nar-
row rolls.II Plastic housewraps were developed and the exterior
“air infiltration barrier”** was introduced (Figure 3 and Photo 5).
It was an amazing transformation in retrospect. Tar paper
was introduced first to control air and then it took on a rain
control function. Its original air control function was for-
gotten when sheet goods such as plywood and OSB replaced
exterior (and very air leaky) board sheathing. Now the air
control function was back. But to a production builder, the
water control function was still more important. And for
good reason. Builders do not get calls in the middle of the
night saying their buildings are leaking air, but they do get
those calls when they are leaking rainwater.
# The 2012 IECC requires that homes in cold climates are constructed such that they are less than 3 ach at 50 Pa and the “thermal bypass checklist” is prescriptively listed as a code requirement. II And you couldn’t print advertising and logos on it to turn your building into a billboard.** Tar paper was originally introduced 100 years earlier to keep drafts out of exterior walls; hence the initial focus on “air infiltration” rather than airflow from both the interior and exterior.
COLUMN BUILDING SCIENCES
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PHOTO 6 (LEFT) Robust Rainwater Control. Many elegant and clever accessories were introduced to deal with rainwater control particularly at window-to-wall interfaces. This is a formable and flexible membrane “pan flashing” system. PHOTO 7 (RIGHT) More Robust Rainwater Control. Beautiful “under window gutter,” pan flashing, sealed to the interior of the window unit for air barrier continuity.
PHOTO 8 Fully Adhered Membrane. Ultra-high levels of airtight-ness with ultra-high levels of cost. Not the easiest stuff to install either. I should know, this is my place.
PHOTO 9 (LEFT) Fluid-Applied Air Barrier. The coatings needed to be able to span joints, and they needed to be vapor permeable. And their most important function, rainwater control, could not be compro-mised. PHOTO 10 (RIGHT) Water Control/Air Control Continuity. The fluid-applied coating must connect to the air control layer of the roof assembly and to the air control layer of the foundation assembly.
PHOTO 11 (LEFT6) Window Opening. Origami is not a necessary skill with fluid-applied flashing systems. PHOTO 12 (RIGHT) Another Window Opening. Some systems require fabric reinforce-ment at critical interfaces.
The “new” air infiltration barriers needed
to be robust rainwater control layers. Many
elegant and clever accessories were intro-
duced to deal with rainwater control partic-
ularly at window-to-wall interfaces (Photos 6
and 7).
But very high levels of airtightness were
still elusive to production builders using
exterior housewraps. They were difficult
to work with—flexible films on the exterior
proved to have similar issues to the experi-
ence with flexible films on the interior.
How about fully adhered membranes?
Yup, they worked big time (Photo 8). Ultra
high levels of airtightness were achiev-
able—but at ultra high levels of cost. This
was a great commercial building enclo-
sure technology that failed to get traction
residentially mostly due to cost. They were
not easiest thing to install either. There
were also physics related issues. Until
very recently no vapor open fully adhered
membranes were available, which meant
that insulation needed to be installed outboard of the
membranes to control the temperature of the condens-
ing surface during heating—the condensing surface
being the interior of the exterior sheathing—typically
plywood or OSB.
On the commercial side fluid-applied air barriers
began to make inroads due to their competitive cost
and relative ease of installation. It was only a matter of
time before they appeared residentially (Photos 9 and
10). Overcoming the technical challenges has not proven
to be easy. The coatings needed to be able to span joints
and they needed to be vapor permeable. And their most
important function, rainwater control could not be com-
promised. After a decade of experience—principally on
the commercial side—we are seeing products that are
working. Origami is no longer a required skill to flash a
window opening (Photos 11 and 12).††
†† Why not just get rid of the damn window? It is a big thermal hole in the wall. It leaks rainwater. Itleaks air. It is expensive. My life as an engineer would be so much simpler. This, of course, is why wedo not let engineers design buildings that people actually live in and work in. We need architects.
COLUMN BUILDING SCIENCES
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COMPREHENSIVE COVERAGE OF DISTRICT HEATING AND COOLING SYSTEM DESIGN
AVAILABLE NOWPrice: $179 ($152 ASHRAE Member)www.ashrae.org/districtguide
5 4 A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 5
FIGURE 4 (LEFT) Exterior Sheathing Air Barrier. Turning the sheathing itself into both the water control layer and air control layer. PHOTO 13 (TOP) Sheathing Water and Air Control Layer. The sheathing in this system is pre-coated with a water control layer. Tape is used to provide water control and air control layer continuity. FIGURE 5 (RIGHT) Insulating Sheathing Air Barrier. Adding the function of thermal control to the sheathing in addition to water control and air control. PHOTO 14 (BOTTOM) Insulating Sheathing Water and Air Control Layer. The insulating sheathing provides three functions in this approach: water control, air control and thermal control.
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 55 6
What about turning the sheath-
ing itself into both the water con-
trol layer and air control layer?
Yes, see Figure 4 and Photo 13. You
could even have the sheathing be
the thermal control layer (Figure 5
and Photo 14).
You still need to deal with the
joints of course. Tapes are cur-
rently the technology of choice,
but I see that changing. I see fluid-
applied joint systems replacing
tapes—due to speed, cost, surface
adhesion advantages and appli-
cation temperature advantages
(Photo 15).
So where are we after 40 years?
We went from the interior to the
exterior with air barriers. And we
went from combining the vapor
barrier with the air barrier on
the inside to combining the water
control layer with the air barrier
on the outside. We went from films
on the inside to sheet goods on the
inside. Then we went from films
on the outside to sheet goods on
the outside. We went from caulk-
ing and the black death on the
inside to tapes and fluid-applied
joint systems on the outside. We
are not done of course. But we are
well on the way. It is only a matter
of time that production builders
move the airtightness bar from 3
ach at 50 Pa to 1 ach at 50 Pa.
BibliographyHutcheon, N.B. 1953. “Fundamental
Consideration in the Design of Exterior Walls for Building.” NRC Paper No. 3087, DBR No. 37. Division of Building Research, National Research Council of Canada.
PHOTO 15 Fluid-Applied Joint System. Replacing tapes with fluid-applied joint systems is now possible.
Hutcheon, N.B. 1978. “Forty Years of VaporBarriers.” Canadian Consulting Engineer, special publication on Moisture Control.
Rowley, F.B., “A Theory Covering the Transfer of Vapor Through Materials.” ASHVE Transactions 45:545, 1939.
COLUMN BUILDING SCIENCES
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 55 8
TECHNICAL FEATURE
Mark Hydeman, P.E., is a principal of Taylor Engineering, LLC. He was the principal investigator of RP-1455 and is the chair of GPC-36. Steven T. Taylor, P.E., is a principal of Taylor Engineering LLC. He is the research chair for TC 1.4. Brent Eubanks, P.E., is a mechanical engineer at Taylor Engineering, LLC. He was a key member of the RP-1455 team and is a corresponding member of GPC-36.
Control Sequences &Controller ProgrammingController ProgrammingControllerBY MARK HYDEMAN, P.E., FELLOW MEMBER ASHRAE; STEVEN T. TAYLOR, P.E., FELLOW MEMBER ASHRAE; AND BRENT EUBANKS, P.E., ASSOCIATE MEMBER ASHRAE
Since the inception of direct of direct of digital control (DDC) systems, control system manu-facturers and their customers had to choose between two fundamentally different fundamentally different fundamentallyapproaches to control system programming:
• Configurable controllers, where control logic is
largely preprogrammed, allowing only a few configura-
tion points and setpoints to be adjusted by the user; and
• Fully programmable controllers, where users can pro-
gram whatever sequences they want into the controller.
Configurable controllers have several advantages:
the control logic and programming are pretested and
debugged, reducing installation and commissioning
time. These controllers are almost plug-and-play, with
only minor configuration work required. But configu-
rable controls developed the reputation of having overly
simplistic control logic that sometimes did not meet the
requirements of energy and indoor air quality standards.
Unfortunately, using fully programmable controllers
presents its own challenges. Even though many HVAC
applications are very similar, if not identical, there are
no industry standards for control sequences. This results
in the following problems and inefficiencies:
• Almost every application is treated uniquely, often
with custom logic that must be prepared and debugged
over and over again. The result is a waste of resources
and, because of the limited time devoted to system pro-
gramming and commissioning, systems that are never
fully debugged and free of operational problems.
• Control sequences are often poorly written or
incomplete. Writing precise, concise, and bug-free
sequences is difficult given the complexities of modern
HVAC systems and few engineers do it well. Installing
contractors are often left to complete or correct poorly
written sequences often without a complete under-
standing of the design intent.
• Control sequences mandated by energy efficiency
standards such as ASHRAE/IES Standard 90.1-2013,
Energy Standard for New Buildings Except Low-Rise Residen-
tial Buildings. and indoor air quality standards such as
ASHRAE Standard 62.1-2013, Ventilation for Acceptable
Indoor Air Quality. are not always implemented cor-
rectly due to lack of familiarity by design engineers
and DDC system programmers.
RP-1455 and Guideline 36
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 5 9
TECHNICAL FEATURE
• The commercial control system market is extremely
competitive, often resulting in insufficient time devoted
to system programming and commissioning, in part
because the custom nature of the programming for each
project is so time intensive.
• DDC systems are very powerful, yet their power
is not fully used by most engineers. For instance, few
systems are programmed with real-time diagnostic
algorithms to detect faults, yet almost all systems have
the hardware and software capability to do so. These
diagnostics could be used to detect system faults that
result in energy waste or failure to maintain process or
comfort conditions.
• Specified alarm logic varies from generating too few
alarms, allowing faults to occur without the knowledge
of building operators, to generating too many alarms
that quickly become ignored by building operators.
Hierarchical fault detection can be used to prevent nui-
sance alarms as described below.
Ideally, standardized high performance, optimized
sequences should be developed that can be prepro-
grammed into controllers, providing the benefits of con-
figurable controllers while not sacrificing performance.
Research Project 1455In 2008, Research Project 1455-RP1 was initiated to
develop “best of class” HVAC system control sequences.
This first phase included developing optimized control
sequences for air distribution and terminal subsystems
including single zone VAV AHUs, multiple-zone VAV
AHUs, and a variety of VAV terminal units, including sin-
gle-duct, dual-duct, and fan-powered. These sequences
were derived from controls specifications submitted by
research partners including engineering consultants,
government institutions, and academic researchers. As
such, they embody dozens of person-years of design and
commissioning experience. A second-phase research
project (discussed further below) is being developed to
address heating and cooling plants and hydronic distri-
bution systems.
These standardized advanced control sequences for
common HVAC applications will provide the following
benefits:
• Reduce engineering time for design engineers.
Rather than develop sequences themselves, they can
adapt standard sequences that have been proven to
perform.
• Reduce programming and commissioning time for
contractors.
• Reduce energy consumption by making systems less
dependent on proper implementation and commission-
ing of control sequences.
• Reduce energy consumption by ensuring that
proven, cost effective strategies, including those re-
quired by ASHRAE standards and building codes, are
fully implemented.
• Improve indoor air quality by insuring control
sequences are in compliance with IAQ standards and
codes such as Standard 62.1.
• Reduce energy consumption and reduce system
downtime by including diagnostic software to detect and
diagnose air handler faults and make operators aware of
them before they cause performance problems.
In addition to the written sequences, the RP-1455
deliverables include companion control schematics and
points lists for each of the systems. There are application
notes in the sequences that clarify the logic behind or
application of the written sequences.
As part of RP-1455, functional logic diagrams of the
sequences were created and they were programmed
into one manufacturer’s controllers and bench tested.
This both verified that the written sequences could be
programmed and that these sequences could be imple-
mented in commonly available commercial HVAC con-
troller hardware. A future research project (discussed
further below) will test the sequences in a real facility.
However, RP-1455 is based on control sequences that
have been proven in the field, so this process is expected
to help fine-tune the logic rather than lead to major
revisions. This project will also develop functional
performance tests to allow manufacturers to test their
implementation of the sequences to ensure they were
correctly programmed.
Guideline 36At the conclusion of RP-1455, ASHRAE Guideline 36,
“High Performance Sequences of Operation for HVAC
Systems” was created to publish and maintain these best
of class sequences and future best of class sequences
for other systems. The guideline committee will keep
the sequences up to date by evaluating and processing
recommendations for changes from users to improve
performance or fix bugs. The sequences will ultimately
be expanded to include sequences for heating and
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 56 0
cooling plant and hydronic systems,
dedicated outdoor air systems,
radiant heating and cooling sys-
tems, etc., whether developed from
research projects or recommended
by engineers, manufacturers, and
contractors. The committee will also
maintain functional performance
tests used by DDC manufacturers
and commissioning agents to verify
that sequences have been properly
programmed.
The latest version of Guideline 36,
as well as news, updates and sup-
porting material can be found at
the Guideline Project Committee
36 public website (http://gpc36.
savemyenergy.com/).Information on
how to join the committee is avail-
able for those who wish to become
formally involved in the process of
developing this Guideline.
Once the Guideline is published,
it is expected that design engineers
will be able to use them as the basis
of control for standard system con-
figurations. For standard systems, it
might be possible to simply include
in their specifications a table of
ASHRAE Guideline 36 sequences
with check boxes for the paragraph
numbers that are applicable to their
project. Having a standardized basis
for the sequences will reduce the
burden in writing control sequences
and improve the operation of those
sequences in the field. Controls
manufacturers are expected to pre-
program the sequences into their
controllers and verify the program-
ming is correct with factory per-
formed functional tests. Then con-
trol contractors can simply use the
programming directly with minimal
configuration. Commissioning work
could then consist simply of verify-
ing that configuration and setpoints
are correct; field functional testing
of programming using standardized
functional performance tests should
be less burdensome.
Status and Future WorkGuideline 36 will be issued
for an advisory public review
soon and is available for down-
load from the GPC-36 public
site. It will include the RP-1455
sequences as issued in the proj-
ect’s final report with slight modi-
fications (primarily clarifications
of language, plus a couple of
improvements to logic). The com-
ments received from this review
will be used to create a publica-
tion public review expected to be
issued late 2015 or early 2016.
The Guideline committee will also
adapt the work of future ASHRAE
research projects into the Guideline
as the work is completed. The fol-
lowing are active ASHRAE proj-
ects expected to be adapted into
Guideline 36 sequences in future
addenda:
• 1587-RP: “Control Loop Per-
formance Assessment.” Creates a
metric for determining if control
loops are tuned, designed to be
programmed into controllers for
real-time assessment of loops.
• 1746-TRP: “Validation of RP-
1455 Advanced Control Sequences
for HVAC Systems – Air Distribu-
tion and Terminal Systems.” Tests
RP-1455 sequences in real building
environment using formal function-
al tests to test stability and perfor-
mance.
• 1747-TRP: “Implementation of
RP-1547 CO2-based Demand Con-
trolled Ventilation for Multiple Zone
HVAC Systems in Direct Digital Sys-
tems.” Creates workable sequences
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 56 2
from the RP-1547 results, which is
a theoretical approach to Standard
62.1-based CO2 demand controlled
ventilation.
• 1711-WS: “Advanced Sequences
of Operation for HVAC Systems –
Phase II Central Plants and Hydronic
Systems.” The second phase of RP-
1455 that includes chilled water and
hot water plants and distribution
systems.
ConclusionsIt is expected that most DDC
system manufacturers will pre-
program the ASHRAE Guideline 36
sequences into their systems so that
they can be used directly or easily
adapted for most any HVAC system
application. Therefore, the plug-
and-play benefits of configurable
controllers are realized without
sacrificing energy performance and
occupant comfort.
Guideline 36 is expected to be
published in 2015 or early 2016.
But that should not prevent the
RP-1455 sequences from being
used right now. They are currently
available by downloading the
RP-1455 reports from the ASHRAE
website, or by downloading the
review draft of Guideline 36 at
http://gpc36.savemyenergy.com/.
Engineers can duplicate some or
all of the sequences in their con-
trol specifications. Manufacturers
should also start programming
the sequences into their systems
right now in anticipation of their
being specified by engineers and
to gain an advantage over their
competitors.
References1. Hydeman et al, Final Report ASHRAE
RP-1455 Advanced Control Sequences for HVAC Systems, Phase I, Jan. 14, 2014.
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 56 4
BUILDING AT A GLANCE
Brett Griffin, P.E., is vice president at Environmental Systems Design, Chicago.
BY BRETT GRIFFIN, P.E., MEMBER ASHRAE
The heart of the mechanical sys-tem for this data campus is thechiller plant. Due to aggressivespeed to market and flexibilityrequirements, the chiller plantwas designed to be modular andscalable to allow for the plant tobe stick built onsite or pre-builtoffsite.
Data CenterEconomizer Efficiency
HONORABLE MENTIONINDUSTRIAL FACILITIES OR PROCESSES, NEW
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
Digital Chicago Datacampus
Location: Franklin Park, Ill.
Owner: Digital Realty
Principal Use: Data Center
Includes: 80,000 ft2 data center white space (across seven suites); 16,000 ft2 office space; 64,000 ft2 electrical support space; 5,000 ft2 chiller plant
Gross Square Footage: 570,000 across three buildings
Conditioned Space Square Footage: 165,000 to date
Substantial Completion/Occupancy: Multiple phases. Phase 1 completed May 2013. Phase 2 completed January 2015.
Data center design has always been associated withwords like availability, reliability, and precision cool-ing. Although availability and availability and availability reliability remain reliability remain reliability critical,energy efficiency,energy efficiency,energy flexibility, scalability, speed to market,and cost effectiveness are driving modern driving modern driving data centerdesign. The Digital Chicago Datacampus took advantage took advantage tookof efficiencyof efficiencyof improvements efficiency improvements efficiency made possible by improved by improved byserver equipment thermal tolerances, which open upthe opportunity to opportunity to opportunity condition a data center space withoutmechanical cooling for cooling for cooling significant portions of the of the of year ina wide range of climates. of climates. of The campus also integrates theefficiency improvementsefficiency improvementsefficiency with the concepts of modular- of modular- ofity, repeatability, and speed to market. The result is afinal product that was not only reliable only reliable only and energy effi- energy effi- energycient, but also relatively simple relatively simple relatively to build, operate, main-tain, and expand.
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 6 5
ABOVE Phase 1 secured customer entrance.
LEFT Arial view of entire Datacampus site.
2015 ASHRAE TECHNOLOGY TECHNOLOGY AWARD CASE STUDIES
This facility is designed for multi-tenant data center
use with a master plan involving multiple buildings and
phases of construction on a single site. Phase 1A and
1B have been occupied for over a year and consisted of
redeveloping a 110,000 ft2 (10 220 m2) building into data
center space, electrical infrastructure, and flex office
space, as well as a new 5,000 ft2 (470 m2) water-cooled
chiller plant building that was pre-assembled off site.
Phase 2 was recently completed and consisted of two
15,000 ft2 (1 400 m2) data center suites with associ-
ated electrical support infrastructure located within
an adjacent 292,000 ft2 (21 130 m2)building. Each
phase is designed to be stand-alone, but also cross-
tied through the chilled water system for increased
flexibility and redundancy.
The master plan includes a new chilled water plant
for each phase of construction. However, the chilled
water distribution supporting Phase 1 was cross-tied to
support Phase 2 due to available capacity of the Phase 1
plant. Future phases will also take advantage of remain-
ing on-site chilled water capacity until the load requires
a new parallel chilled water plant to be installed.
The distribution piping is arranged in a 2N looped con-
figuration with connection points and isolation valves in
place to allow new chilled water plants to be installed and
fully commissioned without affecting the live loads of the
existing data centers. The site is ultimately designed to
accommodate over 577,000 gross square feet (52 950 m2)
of space, including 270,000 ft2 (25 085 m2) of white space
supporting 31.9 MW of data center IT load.
Mechanical Design OverviewThe mechanical system is designed to be concurrently
maintainable, modular, and scalable. Compared to
other similar size and type of systems it is also cost effec-
tive, energy efficient, and simple to operate.
The heart of the mechanical system is the chilled water
plant. It consists of water-cooled centrifugal chillers with
open loop cooling towers for heat rejection and plate and
frame heat exchangers for series (integrated) waterside
economization. The distribution design uses primary-sec-
ondary chilled water pumping and thermal and condenser
water storage for thermal ride-through and back-up.
All of the equipment and associated piping is concur-
rently maintainable and installed in a modular and
redundant manner such that each “line-up” of capacity
equipment (chiller, cooling tower, heat exchanger, con-
denser water pump, and primary chilled water pump) is
repeatable and can be installed in 12 ft (3.7 m2) wide by
40 ft (12.2 m2) long shipping containers, or field erected
on site, depending on schedule and site constraints.
The modular design is extremely important for this
project because of the sheer size of the site and magnitude
TABLE 1 Breakdown of mechanical system energy use in each mode of operation. In this application, the only variable affecting cooling load is the process load and the only variable affecting efficiency, other than percent load, is ambient wet-bulb. Excel was used for energy modeling.
KW/TON
FULL MECH. COOLING
PARTIAL ECONOMIZER
FULL ECONOMIZER
CT 0.037 0.037 0.019
CWP 0.061 0.070 0.061
CH 0.438 0.243 0.000
PCHWP 0.020 0.020 0.000
SCHWP 0.029 0.038 0.038
CRAH Units 0.127 0.127 0.127
Makeup Air Unit 0.073 0.004 0.073
Total Cooling System 0.784 0.539 0.318
% Hours Annually 7% 32% 61%
Annualized kW/ton 0.055 0.17 0.19
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 56 6
of the master planned infrastructure. It allows for scal-
ability and flexibility to fully use the site over time, giv-
ing ownership the opportunity to defer capital cost of
equipment and further improve speed to market for each
deliverable. This delivery model allows the owner to offer
a superior product at a cost-competitive rate.
The modular concept started with Phase 1 of this project.
The chilled water plant was manufactured off-site with
two chillers, pumps, cooling towers, and heat exchang-
ers initially (Phase 1A). The remaining equipment for
the Phase 1 plant was installed and commissioned later
when new leases were signed (Phase 1B). This concept was
taken advantage of again when the leasable white space
expanded into Phase 2 of the site.
Even though the design included a
new chilled water plant and new 2N
chilled water piping loop dedicated
to the Phase 2 spaces, sufficient avail-
able capacity remained on the Phase
1 chilled water plant, so the Phase 2
plant was deferred.
The total capacity of each chilled water plant is 2,400
tons at (N+1) redundancy and is dedicated to only the
critical cooling loads (data center and UPS rooms). The
site is designed for up to five identical 2,400 ton chilled
water plants. With over a year of operation under its
belt, the entire mechanical system operates on an aver-
age of 0.415 kW/ton annually with a mechanical partial
power utilization effectiveness (PUE) of 1.135 (Table 2).
This is in large part due to the extraordinarily high
number of economizer hours it has offered.
Energy Efficiency & Environmental ImpactThe term “economizer” refers to the mode of cool-
ing where there are no compressors operating (full
economizer) or when at least a portion of the cooling is
achieved without compressors (partial economizer). For
a waterside economizer, this means directly transferring
heat from a relatively warm fluid (chilled water return-
ing from the heat load) to a relatively cold fluid (con-
denser water leaving the cooling towers) and rejecting
this heat to the outdoors.
To optimize this mode of operation, three design fea-
tures were considered (listed in order of importance):
elevating the “warm” fluid temperatures (chilled water
supply and return), reducing the “cold” fluid tempera-
ture (condenser water supply), and minimizing the heat
transfer losses through cooling towers, heat exchangers,
and cooling coils.
What determines the setpoint of the chilled water sup-
ply temperature is the maximum allowable air tempera-
ture entering the servers (cold aisle temperature). This
design value was guided by the published guidelines
in the ASHRAE Datacom Series of books and was set at
70°F (21°C) dry-bulb with a minimum dew point of 40°F
(4.5°C). This allowed the chilled water system to supply
between 60°F (15.5°C) and 63°F (17°C) chilled water. With
a tight approach temperature across the heat exchangers
and oversized cooling towers, the plant is allowed to oper-
ate in full economizer mode whenever the ambient wet-
bulb temperature is below 52°F (11°C)
(61% of time).
The integrated economizer was fur-
ther optimized by carefully selecting
the right cooling coils, control valves,
and secondary chilled water pumps
to allow for a constant 17°F chilled
water DT at all loads, resulting in a chilled water return
temperature of 77°F (25°C). This allows the plant to
operate in partial economizer mode with ambient con-
ditions at or below 68°F (20°C) wet bulb (93% of time).
Full mechanical cooling is required only 7% of the time.
See Figure 1.
This system is designed to operate in economizer
mode at all load conditions. This is especially important
because most data centers operate at part load for the
majority of their life time, but are usually only optimized
for their peak load performance. Currently, over 5,000
tons of chilled water CRAH unit capacity are online,
operating under automatic temperature control (N+2
in every suite and UPS rooms), with only a combined
chilled water load of less than 750 tons (15% load to coil
capacity ratio). By contrast, at this low load, most sys-
tems would supply much more chilled water flow than
required, resulting in more pumping horsepower than
necessary and a very low chilled water return tempera-
ture (low DT syndrome), virtually eliminating any ben-
efit of partial economizer operation.
After 17 months of operation (across two full sum-
mers) and a constant load of less than the capacity of one
chiller, the chillers only have a total of 4,419 runtime
hours combined (from BAS trending). This is only 35%
of the total hours across this span and also includes all
the hours of start-up and commissioning, validating and
TABLE 2 Annual partial PUE. Partial PUE is IT load plus mechanical load, divided by IT load.
ENERGY USAGE ANNUAL VALUE
IT Load (kWh) 64,561,200
Mechanical Loads (kWh) 8,724,960
Partial PUE 1.135
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 56 8
FIGURE 3 Simplified chilled water flow diagram—full mechanical cooling mode.
Open (Typ.)
90°F CT-2
CH-1
On (Typ.)
77.5°F
0
Off
CHWR=77.5°F
OpenP-4
P-3
CWS ≥ 75°F
Open
77.5°F
CH-2
60°F 60°F
condenser water supply temperature is greater than the
chilled water return temperature by an offset of 2.5°F
(1.38°C) (7% of year). See Figure 3.
2. The plant operates in partial economizer mode when
the condenser water supply temperature is between the
chilled water supply temperature setpoint of 60°F (15.5°C)
and 3°F (1.4°C) below the chilled water return tempera-
ture of 77°F (25°C)(32% of year). (Only two valves change
exceeding the design calculations of operating at least
61% of time on full economizer, even at minimum load.
In addition, because all of the CRAH units are able
to operate together in parallel with such low loads, the
fans are all operating at their minimum speeds at a frac-
tion of the energy of the same fans at full speed. Figure
2 highlights some of the design fea-
tures that allow this system to oper-
ate so efficiently and take advantage
of these economizer hours at all load
conditions.
Operation and MaintenanceThe chiller plant control system
is simple and reliable. All of the
equipment and piping is concur-
rently maintainable. The control
of the central chilled water plant
is achieved through three simple
sequences. (The only variable affect-
ing operational modes is system
water temperature, not flow or load
or ambient conditions.)
1. The plant operates in 100%
mechanical cooling mode when the
CT-1
P-1
HX-1
FIGURE 2 Simplified schematic heat rejection flow diagram.
95°F1
IT Equipment
26
65°F
CRAH Unit 60°FSCHWP
CWP
77.5°F3
5
CT58°F
HX CH4
7
PCHWP
95°F1
IT Equipment
26
65°F
CRAH Unit 60°FSCHWP
CWP
77.5°F3
5
CT58°F
HX CH4
7
PCHWP
1
23
4
5
67
Space return air temperature elevated to 95°F DB. CRAH unit fans are controlled to modulate to maintain this temperature at all loads.
CRAH unit cooling coils are selected at high chilled water DT and low approach temperature to ADP (5°F).
CRAH units are equipped with pressure independent control valves to maintain design chilled water DT (17°F) and highest return chilled water temperature at all loads (77°F).
HX located in hot secondary chilled water return and immediately downstream of cooling towers to exchange heat between the hottest indoor fluid and the coldest outdoor fluid. HX sized for low approach (2.5°F) with design flow, lower at reduced flow.
Sized for low approach (5°F at design WB). CT piped in header and designed to allow partial flow rate to allow operators to run in running redundancy mode to save tower fan energy. Energy model does not assume running redundancy, however, CT leaving condenser water setpoint is 58°F year-round for simple control and optimum economizer hours. When ambient WB is above 52°F the fans will naturally run at 100% fan speed to make the coldest water possible. When below 52°F the fans will slow down to maintain temperature.
CRAH units operate in running redundancy for simple controls and fan energy savings.
HX located on secondary loop so PCHWPs can turn off during full economizer.
¯
¯¯
¯
¯
¯¯
FIGURE 1 Bin hours for Chicago’s O’Hare airport (top) and data center chiller plant modes of operation (bottom).
0
0
00
0 0 0
72
9
89 164 1443
22555
744672
725648
394
341
539
192
579
585
617
519
665744
15100
800
700
600
500
400
300
200
100
0 Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sept. Oct. Nov. Dec.
Bin
Hour
s
19
CWP OPERATING MODE ANNUAL HOURS % OF HOURS
Mechanical Cooling 654 7%
Partial Economizer 2,787 32%Full Economizer 5,319 61%
0 0 09
100% Mechanical Cooling Partial Economizer 100% Economizer
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 0
position based on two temperature
measurements, independent of load
and flow.) See Figure 4.
3. The plant operates in 100%
economizer mode when the con-
denser water supply temperature is
at or below the chilled water sup-
ply temperature setpoint of 60°F
(15.5°C) (61% of year). (Only two
valves change position based on one
temperature measurement and one
setpoint, again independent of load
and flow.) See Figure 5.
As stated previously, the secondary
chilled water return temperature
remains constant at all ambient and
load conditions. The cooling tower
fans operate with a single condenser
water supply temperature setpoint
year-round, meaning that above
52°F (11°C) ambient wet-bulb the
fans operate at 100% speed, and they
modulate when the ambient wet-
bulb is below (52°F °C) (61% of year).
The condenser water pumps and pri-
mary chilled water pumps operate at
constant speed when enabled, and
the secondary chilled water pumps
modulate to maintain constant
chilled water system differential
pressure.
Lastly, the ventilation system pro-
viding code minimum ventilation,
pressurization, and makeup air
for the battery exhaust is handled
through small dedicated makeup air
units (MAUs) with packaged controls.
FIGURE 4 Simplified chilled water flow diagram—partial economizer cooling mode.
Cost EffectivenessThis system is unique to the owner because it uses a
central cooling plant for multiple data center suites.
Until now, central plants were considered cost and
schedule prohibitive as they required too much up-front
capital and longer construction schedules than systems
that use mostly manufactured unitary products such as
air-cooled chillers, DX split systems, and rooftop units.
Finally, during the design phase, the project team
worked with the local utility company through their
local utility rebate program. The requirements of the
program are to compare the installed mechanical cool-
ing system to a baseline mechanical cooling system
established by the utility company and verify the sav-
ings through a strict Measurement and Verification
plan, also established by the utility company. At $0.07/
kWh, the overall savings would be approximately
$325,000 per year for Phase 1 alone.
Open (Typ.)
CT-2
CH-1
60°F < CHWR <77°F (Typ.)
P-2
CHWR=77.5°F
ClosedP-4
P-3
60°F ≤ CWS < 75°F
CH-2
60°F 60°F
CT-1
P-1
HX-1
Closed
FIGURE 5 Simplified chilled water flow diagram—full economizer cooling mode.
Closed/Bypass(Typ.)
CT-2
CH-1
P-2
CHWR=77.5°F
ClosedP-4
P-3
CWS < 60°F
CH-2
CT-1
P-1
HX-1
Closed
Off(Typ.)
CHWS=60°F
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
Solving Low Delta T
> Learn Morewww.energyvalve.com
Measures Energy
Controls Power
ManagesDelta T
2014 AHR InnovationAward Winner
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 2
COLUMN DATA CENTERS
Donald L. Beaty
Donald L. Beaty, P.E., is president and David Quirk, P.E., is vice president of DLB AssociatesConsulting Engineers, in Eatontown, N.J. Beaty is publications chair and Quirk is the chair of ASHRAE TC 9.9.
BY DONALD L. BEATY, P.E., FELLOW ASHRAE; DAVID QUIRK, P.E., MEMBER ASHRAE
Are Data Centers Data Centers Data Drying Up? Drying Up? DryingValuable new data new data new on the relationship between humidity and humidity and humidity electrostatic discharge(ESD) in a data center environment has recently been recently been recently published through ASHRAEResearch Project RP-1499. The relationship between ESD and humidity has humidity has humidity long been long been longanecdotally known,anecdotally known,anecdotally but insufficiently quantified. insufficiently quantified. insufficiently
Everyone has had the experience of walking on a car-
pet and touching a metal surface soon afterwards – the
result is an electrostatic shock.
The voltage of the shock ranges from a couple hun-
dred volts to many thousand volts, and if the item being
touched is sensitive electronics, there is a potential to
damage that equipment. Likewise, these shocks tend to
have much greater frequency (and magnitude) in the
winter when the humidity is lower than in the summer
when the humidity is higher.
Historical Trends in Data Center Humidification IT equipment manufacturers have long known that
electrostatic discharges occur at low relative humidity
levels, and that these discharges can cause IT equipment
failures. Legacy data centers were designed with a nar-
row relative humidity deadband: 45-55% RH.
When ASHRAE TC 9.9 first published Thermal
Guidelines for Data Processing Environments in 2004, the
recommended RH was a little more relaxed to the
range of 40% to 55% RH, but introduced an Allowable
Range that was set at a much broader 20% to 80%.
In the second edition of Thermal Guidelines (2008), the
recommended humidity level was further relaxed to
5.5°C (42°F) dew point on the low side, and the lower of
60% RH and 15°C (59°F) dew point on the high side. Figure
1 plots the 2004 and 2008 recommended envelopes on a
psychrometric chart. The allowable range stayed the same
between the first and second editions, at 20% to 80% RH
and is plotted on a psychrometric chart in Figure 2.
In the latest (third) edition of the Thermal Guidelines,
published in 2012, the recommended range has stayed
the same, but two additional allowable ranges have been
added: A3 and A4 (Figure 3). Both of these ranges allow
for as little as 8% RH on the low side.
Justification for Additional ResearchHumidification can have a significant impact on
energy consumption that extends beyond the simple
consumption of the humidification conditioning equip-
ment itself. For instance, a high minimum humidity
requirement in conjunction with an air-side economizer
could result in blocking out a significant number of
economizer hours and associated energy savings. Due
to the significant impact of high minimum-humidity
threshold requirements on energy consumption of data
centers, ASHRAE TC 9.9 applied and received approval
from ASHRAE for a research project to better under-
stand the correlation between humidity levels and ESD.
The Research ProjectWhile it may seem like a fairly straightforward
research project, the actual implementation of a study
to correlate ESD with humidity is complex. Part of
the setup for the research involved obtaining a better
understanding of exactly what mechanisms occur to
create these discharges.
For instance, a person walking will definitely build up
a charge (and the charging process was also studied in
this report), but how will this be discharged? Will the
person discharge by touching a piece of IT equipment
with their hand, or will contact be made by first touch-
ing the equipment with something metallic, such as a
flash drive? The magnitude and duration of these dis-
charges will be different, and both instances were tested
as part of the research.
The type of shoe worn by the occupant matters as does
the type of flooring. At the least granular level, one can
New Research on Humidity and its Impact on Electrostatic Discharge
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 7 3
COLUMN DATA CENTERS
classify shoes as ESD dissipative or non-ESD dissipative,
and the floor as ESD dissipative or non-ESD dissipative.
This study went into far more detail. For instance, 11
different shoe types were investigated and a total of 13
types of floors were also investigated (see Table 1 for the
full list).
Finally, a total of four relative humidity levels were
examined: 60%, 35%, 15%, and (as an added require-
ment) 8%. While 8% RH may seem excessively low, as
mentioned earlier, two new environmental classes
of IT equipment (A3 and A4) were added as Thermal
Guidelines environmental classes in the middle of this
research project, and TC 9.9 was able to obtain ASHRAE
approval for the scope of the research to be extended
from 15% RH down to 8% RH.
ESD in Real Life vs. Research SimulationIn real life, ESD can cause:
• Self-correcting errors (such as a lost package in LAN
traffic);
• An upset that may need user intervention; or
• Actual physical damage to IT equipment.
under environmental condition B.” If one has empirical
data on the ESD failure rate at one relative humidity, the
results of the study allow one to estimate the change in
For research purposes,
measurements of these
failure modes were not spe-
cifically documented, as the
robustness of specific mod-
els of equipment varies so
widely. Rather, voltages and
durations were measured,
and these were compared
to the industry standard
voltages (4kV and 8kV)
defined in the International
Electrotechnical
Commission document IEC
61000-4-2.
Rather than absolute values,
the report generally provides
data in terms of relative prob-
abilities of harmful events.
This strategy is similar to the
x-factor that is defined in
Thermal Guidelines.
The value of the x-factor is a ratio, defined as the
“Number of equipment failures under environmental
condition A divided by Number of equipment failures
FIGURE 2 2004 and 2008 allowable ranges.
Relative Humidity90% 80% 70% 60% 50% 40% 30%
80
75
70
65
60
55
50
45403530 20 100
Dew-
Point
Tem
pera
ture
°F
Wet-Bu
lb Tem
peratu
re °F
80
75
70
65
60
55
50
4540
35
35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Dry-Bulb Temperature °F
Recommended
20%
10%
SOUR
CE: A
SHRA
E. M
ODIF
IED
BY D
LB
ASHRAE 2004/2008 – Class 2 Allowable
ASHRAE 2004/2008 – Class 1 Allowable
SOUR
CE: A
SHRA
E. M
ODIF
IED
BY D
LB
80 90% 80%
70%
60%
55%
50%
40%
30%
20%
10%
Wet-Bu
lb Tem
peratu
re °F
75
70
65
60
50
55
45 50 55 60 65 70 75 80 85Dry-Bulb Temperature °F
2004
200880%
60%
40%20%
FIGURE 1 2004 and 2008 recommended ranges.
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 4
a “well-defined pattern” (WDP) as
shown in Figure 4, and a “random
walking experiment” (Random).
People, however, are not the only
generators of electrostatic charge in
data centers. Equipment carts are
one additional source of charge, and
cabling is another.
ResultsThe results of the study fall into sev-
eral categories; this brief article cannot
do justice to the results, but the follow-
ing can be considered a summary.
For evaluating the combined
impact of flooring and footwear in
a data center, the six categories of
data centers examined are shown in
Table 2.
One takeaway from this data is that
the probability of the 4000 Volt and
8000 Volt discharges vary by up to
18 orders of magnitude based on the
type of floors and footwear. These
construction and operations variables
can decrease ESD impact without any
impact on energy consumption.
It should be noted that the
experimental results listed in Table
2 involved walking. Additional
experiments, involving standing
up from an office chair, and taking
off a sweater, were able to generate
higher voltages in humans.
ConclusionsThe research provided sev-
eral conclusions, including the
following:
• Reducing the relative humidity
in a space will increase the voltages
of ESD.
• Reducing the absolute humid-
ity (dew-point temperature) does
not always lead to an increase in
voltages, but the threshold at which
a reversal may occur is low - in the
range of -10°C to 0°C (14°F to 32°F).
• The chair and sweater events
caused very high voltages.
TABLE 1 Floor and shoe test conditions. ©IBM
LOW RH EFFECTS ON DATA CENTER OPERATION
TEST CONDITIONS
FLOOR SHOES
3M 4530 Asia 3M China Slip On
3M 6432 Cond 3M Full Sole
3M 8413 Running Shoe
3M Green Diss DESCO 2 Meg Sole
3M Low Diss DESCO Heel
3M Thin VPI DESCO Full Sole 2 Meg
Epoxy 1A Hush Puppy
Flexco Rubber Red Wing
HPLF Stata Rest
HPLN Sperry
Korean Vinyl Heel Strap
Standard Tile
Wax
FIGURE 3 2012 allowable ranges.
Relative Humidity90% 80% 70% 60% 50% 40% 30%
80
75
70
65
60
55
50
45403530 20 100
Dew-
Point
Tem
pera
ture
°F
Wet-Bu
lb Tem
peratu
re °F
80
75
70
65
60
55
50
4540
35
35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Dry-Bulb Temperature °F
Recommended
A1
A2
A3 A4
20%
10%
SOUR
CE: A
SHRA
E. M
ODIF
IED
BY D
LB
ESD failure rate at another rel-
ative humidity level, all other
factors being equal.
Generating the ChargeBefore a potentially damag-
ing discharge can occur, an
electrostatic discharge first
has to build up. A signifi-
cant portion of the research
was aimed at understanding
these phenomena, since a
significant discharge cannot
be discharged if a charge has
not built up in the first place.
The testing procedures were
generally in compliance with
IEC 61000-4-2, as mentioned
earlier.
For human charging experi-
ments, another standard,
ANSI/ESD STM97.2, defines
• A factor called Relative Humid-
ity Voltage (RHV) can be used to
express the increase in the average
voltages if the humidity is de-
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M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 7 5
creased. For a decrease in relative humidity from 45%
to 8%, the RHV is approximately 3. For a decrease in
relative humidity from 25% to 8%, the RHV is approxi-
mately 1.5.
The RHV would need to be considered in combination
with the relative scale of voltages commonly occurring
in a given environment (based on the combinations of
flooring, shoes, etc.) and the frequency that ESD events
occur based on data center specific operations in order
to determine the complete picture of ESD risks to elec-
tronic equipment failures.
RecommendationsThe study provides general recommendations in a
number of areas. These can probably best be categorized
into the areas of relative humidity levels, flooring and
footwear, grounding, chair and carts, grounding proce-
dures, and cabling.
• For relative humidity levels, the results clearly show
that the lower RH levels create higher discharge voltages
and a higher frequency and potential for development
of higher voltages. In most cases, however, these voltages
are less than the threshold voltages that IT equipment is
FIGURE 4 Well-defined pattern.
Groundable Point A
Right FootStart/End
4
3
21
5
Left FootStart/End 6
Groundable Point B
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 6
designed to withstand, especially if ESD precautions are
taken.
• Using ESD-mitigating flooring and footwear, the
risk of ESD upset and damage can be reduced to an
insignificant level, even if the humidity is allowed
to drop to low values, such as 8%. Unfortunately,
controlling the footwear in most data centers is very
impractical.
• All office chairs and carts selected for use in data
centers should have ESD-mitigating properties.
TABLE 2 Summary data in probability for voltages greater than a threshold value (based on fitted lines).
TYPE OF DATA CENTER 500 VOLT D ISCHARGE PROBAB ILITY 4,000 VOLT D ISCHARGE PROBAB ILITY 8,000 VOLT D ISCHARGE PROBAB ILITY
15% RH & 59°F 50% RH & 80°F 15% RH & 59°F 50% RH & 80°F 15% RH & 59°F 50% RH & 80°F
No Static Control 18% 0.2% 0.5% 3.7 × 10–6 % 0.1% 3.2 × 10–8 %
Dissipative Floors, Dissipative Footwear 16% 19% 0.016% 1.0 × 10–4 % 5.5 × 10–5 %, 2.2 × 10–7 %
Dissipative Floors, Uncontrolled Footwear 34% 5.65% 0.9% 0.001% 0.09% 2.3 × 10–5 %
Conductive Floors, Dissipative Footwear 0.003% 1.6 × 10–7 % 1.8 × 10–7 % 1.8 × 10–11 % 7.4 × 10–9 % 8.9 × 10–13 %
Conductive Floors, Uncontrolled Footwear 8% 0.1% 0.004% 4.7 × 10–10 % 4.1 × 10–5 % 7.5 × 10–13 %
Conductive Rubber Floors, Uncontrolled Footwear 0.1% 9.6 × 10–13 % 8.6 × 10–7 % 1.4 × 10–20 % 1.6 × 10–8 % 3.5 × 10–23 %
• Also grounding straps should be used when before
making contact to any of the sensitive electronics.
• A standard set of ESD-mitigation procedures listed
here will ensure a very low ESD incident rate at all hu-
midity levels tested.
• For the new ASHRAE A3 and A4 environmental
classes, the authors conclude that there is a greater
chance for ESD events, but indicate that this can be
mitigated with proper data center design and good ESD
prevention with operating procedures. In general, the
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M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 7 7
damaging ESD events, however, is
quite interdependent with other
variables in the data center, such
as floor conductance and operating
procedures.
There are many industry “best
practices” and risk mitigation meth-
ods that could be used to avoid dam-
aging ESD on sensitive electronics.
Oftentimes, these mitigation meth-
ods can be hard to implement and
enforce, but especially in light of the
data collected in this project, they
are proven means to reducing the
risks associated with ESD.
The new ESD research has helped
to quantify the ESD risks associated
with lower level humidity levels in
the data center, and has concur-
rently shown other approaches to
mitigating damage to IT equipment
from ESD events. This research pro-
vides guidance for the operation of
data centers in the new ASHRAE A3
and A4 environmental conditions.
It also provides an excellent set of
technical data that could form the
basis for adjustments to ASHRAE’s
recommended and allowable envi-
ronmental ranges for IT equipment
in the future.
For More InformationFor those interested in the details
of this study, the RP-1499 research
project has spawned a wealth of
Technical Papers, as well as a final
report. An initial paper (DE-13-031)
was published in 2013. The recent
2015 Winter Conference in Chicago
increased risk in migrating from 25% RH to 8% RH is
about a 50% increase in the incidence of ESD risk.
Closing CommentsLower relative humidity generally increases both
the frequency and magnitude of ESD discharges.
Whether these increases actually increase the risk
included three more papers, CH-15-005, CH-15-006,
and CH-15-007. These papers can be obtained from the
ASHRAE Bookstore.
References1. IEC 6100-4-2 Electromagnetic Compatibility (EMC) – Part 4-2:
Testing and measurement techniques – Electrostatic discharge im-munity test.
COLUMN DATA CENTERS
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 8 A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 8
BUILDING AT A GLANCE
Art Sutherland is president of Accent Refrigeration Systems in Victoria, BC, Canada.
Energy EfficientIce Rink
FIRST PLACEPUBLIC ASSEMBLY, NEW
The Westhills Recreation
Centre’s outdoor rink offers
an interesting energy bal-
ance opportunity in winter by
providing additional rejected
energy during the heating sea-
son. Even with the extensive
use of energy, 60% of waste heat
is pumped to a nearby housing
development.
2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES
BY ART SUTHERLAND, MEMBER ASHRAE
Westhills Recreation Centre
Location: Langford, BC, Canada
Owner: City of Langford, BC, Canada
Principal Use: Recreation center
Includes: Ice skating, bowling, restaurant, commercial offices
Employees/Occupants: 50 employees and 1,200 maximum occupancy in all areas
Gross Square Footage: 75,000
Conditioned Space Square Footage: 75,000
Substantial Completion/Occupancy: September 2012
Occupancy: 100%
An extensive study conducted study conducted study by Natural by Natural by ResourcesCanada determined that a typical 40,000 ft2 (3716 m2) icerink in Canada will consume an average of 1.5 of 1.5 of million kWhof equivalentof equivalentof energy per energy per energy year. The Westhills RecreationCentre in Langford, British Columbia, is nearly twice nearly twice nearly asbig usesbig usesbig only 768,000 only 768,000 only kWh. And, the refrigeration systemfor the ice surfaces produces so much waste heat thatexcess is shared with a nearby housing nearby housing nearby development. housing development. housing
The 75,000 ft2 (6967 m2) facility consists of an of an of NHL sizeindoor ice rink, an outdoor ice rink and a skating trail skating trail skating join-ing theing theing two rinks together. The facility also facility also facility houses a 20lane bowling alley, bowling alley, bowling restaurant/lounge, party rooms party rooms party and10,000 ft2 (929 m2) of leased of leased of office space with multiplesport-related tenants. The total cost of construction of construction of was$13.5 million, with a $9 million grant from the BuildingCanada Fund.
M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 7 9
ABOVE Westhills Recreation Centre’s NHL size indoor ice rink.
LEFT VFD-driven high efficient ammonia compressors provide refrigeration for the ice rinks in winter and building air conditioning in summer.
2015 ASHRAE TECHNOLOGY TECHNOLOGY AWARD CASE STUDIES
The outdoor ice rink was designed with embedded
refrigeration piping for winter ice and water fixtures to
convert it into a children’s splash park in summer, making
use of the same footprint for both summer and winter.
Eliminating Fossil FuelsThe city of Langford, located on Vancouver Island, has
among the highest natural gas prices in North America.
The project objective was to eliminate natural gas con-
sumption for all heating, hot water and dehumidifica-
tion loads while minimizing electrical consumption
year-round. In fact, the building does not use fossil
fuels at all except in the kitchen, which does use natu-
ral gas. And, it was determined during the preliminary
design phase that the quantity of heat rejected from the
refrigeration to service the three ice surfaces would be
more than enough to satisfy all of the heating loads with
extra heat that could be shared with a nearby housing
community.
The challenge was to ensure that there was heat avail-
able between compressor run cycles and during the
colder periods of the year when the refrigeration was
running less. The outdoor ice rink offered an interesting
energy balance opportunity in Langford’s mild winter by
providing additional waste heat during the peak heating
season, just when it was needed most.
To ensure that there would be no periods between
refrigeration run cycles without heat being available, two
approaches where taken. The refrigeration compressors
and brine pumps were equipped with variable speed
drives. The variable speed drives, controlled by the com-
puter control system, were programmed to operate the
compressors at their lowest permissible speed while pre-
cisely maintaining the temperature setpoint.
This strategy provided a number of benefits. The com-
pressors always operated at their maximum coefficient of
performance (COP) due to the higher saturated suction
temperatures and lower saturated condensing tempera-
tures while running at low speeds. The centrifugal brine
pumps were also modulating their speed and taking
advantage of the Pump Affinity Law, resulting in reduced
electrical consumption. The main objective of perpetuat-
ing the heating cycle was also met as the compressor run
cycles were much longer throughout the day.
A system also had to be designed that would have heat
available during colder periods and when the night set
back control strategy would shut the compressors off. To
achieve this, we required some form of thermal storage.
A cost effective solution was to use the ice rink sub-floor
heating system for thermal storage.
Traditionally, ice rink sub-floor heating systems would
operate at 40°F (4.5°C) to prevent frost heaves caused by
long-term refrigeration operation. To minimize any
impact to the ice surface as a result of higher sub-floor
temperatures, we installed 6 in. (150 mm) of R-5 insula-
tion board between the ice pad and the heating floor,
and around the outside walls. This enabled the tempera-
ture of the sub-floor to be increased to 75°F (24°C). This
“geothermal system on steroids” was cost effective to con-
struct because the civil work, piping mains, pumps and
half the insulation would have been required anyway for a
traditional sub-floor heating system.
During the winter, 100% of the refrigeration waste
heat is harvested with an energy recovery condenser,
which is able to provide 82°F (28°C) glycol temperature
while maintaining 85°F (30°C) condensing tempera-
ture. The warm 82°F (28°C) glycol from the energy
recovery condenser directly provides radiant heating
throughout 19,000 ft2 (1765 m2) of public space.
The concrete floors are maintained at 72°F to 74°F
(22°C to 24°C), which provides an excellent level of
comfort. In mid-winter, an energy recovery heat pump
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 58 0
the energy recovery loop as the heat source. During the
winter, the hot water is produced at a COP of 4.28 (4.02
adjusted for pump horsepower).
The ice rink desiccant dehumidifier was custom
designed for this facility (Figure 1). It uses a low tem-
perature desiccant rotor that can be regenerated at
125°F (52°C), versus the traditional gas-fired rotors
that require 275°F (135°C). The system uses two coils in
will boost the glycol temperature from 95°F
(35°C) to 105°F (40°C), as required, to main-
tain comfort in all areas.
There are 15 HVAC units and two HRVs
interspersed throughout the complex. All of
the air handlers have large close-approach
coils designed to provide heating with 95°F
(35°C) glycol and cooling with 50°F (10°C)
glycol. In very cold months, the heating glycol
temperatures will automatically reset to pro-
vide sufficient heat.
With the combination of long compressor
run times and thermal storage, the building
heat pumps have an uninterrupted energy
source of 75°F (24°C) and supply 95°F (35°C)
FIGURE 1 Energy recovery dehumidifier with cooling coil that services the ice rink.
heating glycol, while operating with an exceptional COP
of 7.97 (7.49 adjusted for pump horsepower).
Domestic hot water for the facility is provided through
two stages. The first stage is free heat from the ammo-
nia desuperheating system and ranges from 100°F to
120°F (38°C to 49°C). The water is then brought up to
140°F (60°C) using a hot water heat pump that also uses
Low Grade Heat 70° to 80°F
Free HeatPump
React In
Dry Air To Rink
Cooling Pump
Chiller Return
Humid Air From Rink
React Out React Pump
Post Heat Pump
Medium Grade Heat 125°F
T
T
T
T
T T
T
T
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 58 2
series to regenerate the desiccant wheel. The first coil is
circuited for the 82°F (28°C) glycol that is directly har-
vested from the ammonia condenser and can temper
the air up to 70°F (21°C). The second coil obtains its heat
from an energy recovery heat pump, which also harvests
heat from the ammonia system and produces 130°F
(54°C) glycol to provide the finished temperature to
regenerate the desiccant wheel.
On a typical 40°F (4°C) winter day the result of this
two-step temperature lift is that the first 35% of the tem-
perature lift is done using free heat and the second 65%
by using a heat pump with a COP of 4.99 (4.68 adjusted
for pump horsepower). The low temperature regenera-
tion results in an air temperature entering the rink in
the 85°F (29°C) range rather than the 115°F (29°C) range,
which is typical of the gas-fired units.
A post-heating coil is installed that uses energy from
the heat pumps to provide comfort heating above the ice
rink bleachers, if required.
As a result of these initiatives, no fossil fuels are used
in the facility other than the use of natural gas in the
kitchen since the complex was commissioned in 2012.
Improving Electrical Energy EfficiencyAnother challenge was keeping electrical consumption
(electricity is provided by hydroelectricity) in check
while using heat pumps in lieu of natural gas. The
primary refrigerant is ammonia, which is inherently
efficient. We used a new model of ultra-high efficient
VFD-driven compressors that handle both the ice rink
duty in winter and the air-conditioning duty in sum-
mer. The compressors have a cooling COP of 4.62 dur-
ing the ice season and a summertime air conditioning
COP of 15.1. The VFD uneven parallel compressors have
a range of 30 to 60 tons (106 to 211 kW) for the small
compressor and 60 to 90 tons (211 to 317 kW) for the
large compressor, allowing them to exactly track the
refrigeration load year-round. With 100% of the energy
being recovered, the compressors have a combined
heat/cool COP of 10.2 in winter. All of the loads in the
complex including fans, pumps and compressors have
a VFD controlled by the building automation system to
minimize energy consumption.
During the summer, the hot water heat pumps extract
heat from the 19,000 ft2 (1765 m2) of radiant floors,
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 58 4
taking advantage of both sides of the heat pump cycle,
which boosts the total heat pump COP to 7.6.
The ice rink will remove 8,000 pounds of snow per
day during normal ice maintenance. When melted in
the snow melt pit, this snow will provide 1,152,000 Btus
(96 ton-hours) of useful cooling that helps shave the
peak off the air conditioning requirement. A submersed
enhanced surface coil is used to extract the energy dur-
ing peak air conditioning hours. The coil has the ability
to deliver 325,000 Btu/h (95 258 kW) of glycol at 45°F
(7°C). This heat transfer can be sustained for three to
four hours per day, depending on how much snow is in
the pit.
Figure 2 shows where the harvested heat was used
within the Westhills ice rink during a single 24 hour
period in October 2012. The facility heating require-
ment was fairly low and the ice rink dehumidification
was fairly high. The outdoor rink was not in operation
so we were not at full waste energy production. The
percentages were calculated from the run times on the
three building heat pumps and run times on the various
distribution pumps, along with the average supply and
return temperatures. This was just a snapshot in time
so the dynamic heating requirements for each load will
change day to day with the various user groups, outdoor
ambient temperature and humidity.
Community Energy SharingEven with the extensive use of energy, only 40% of the
waste energy is required within the complex. Therefore,
FIGURE 2 Ice rink energy use on a typical fall day.
Snow MeltUnderfloor HeatZamboni Hot Water
Building Hot WaterRadiant HeatHVAC Heating
DehumidificationFresh Air VentilationHeat Sent to Housing
56%
3%
13%
6% 3%
5%4%
6%
4%
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M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 8 5
once the on-site geothermal field is satisfied and all of
the zones are within their programed range, the remain-
ing 60% of the heat is transferred via a VFD-driven
pump to a growing housing development 400 yd (366 m)
away as an energy source for the household heat pumps.
The VFD is temperature controlled and programmed
to maintain the ice rink energy loop at 80°F (27°C). A
brazed plate heat exchanger provides a fluid separation
between the housing development energy loop and the
ice rink energy loop. There are just under 500 homes in
the housing development, so the waste energy is only
able to provide a portion of the required heating energy
in winter. This results in absolutely every bit of waste
energy being used from the two ice surfaces and skat-
ing path during the winter. This scenario is much easier
to control in comparison to a situation where there
is too much heat that must be diverted to an outdoor
TABLE 2 Payback for the energy efficiency features, including energy sharing.
Annual Reduction in Natural Gas Consumption $46,928.96
BC Hydro’s Calculated 259,751 kWh Annual Savings with VFDs $15,585.00
Refrigeration and Air Conditioning Energy Efficiency Improvements $5,718.00
Total On-Site Energy Savings $68,231.96
Off-Site Energy Value Sent to Housing Development $41,470.00
Total Energy Savings $109,701.96
Net Cost Over Conventional System $308,988.00
Payback on Energy Efficiency Components 2.81 Years
TABLE 1 Electrical consumption for the Westhills Recreation Complex.
MONTH KILOWATT HOURS B I LLED COST
January 2014 111,070 $7,478.26
February 2014 104,304 $7,084.41
March 2014 91,074 $6,060.16
April 2014 94,609 $5,563.04
May 2014 75,168 $6,095.84
June 2014 62,157 $4,087.19
July 2014 56,600 $3,827.70
7 Month Total 594,982 $40,196.60
Actual Meter Reading Credit 146,850 $10,272.17
Actual Energy Consumed 448,132 $29,924.00
Monthly Average 64,016 $4,274.92
Extrapolated to 1 year 768,192 Annually $51,294.04
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 58 6
condenser. The average value of the approximately
830,000 kWh of energy sent to the housing development
if it were natural gas would be $41,470.
The balance of heat in the housing development is
supplied by two 180 ton (633 kW) VFD-driven ammo-
nia heat pumps that use a geothermal field below a
soccer field as the energy source.
The ammonia heat pumps are only required in the
winter and operate at COPs ranging from 8 to 15. The
heat pumps maintain the housing energy loop at a con-
stant 60°F (16°C), which results in favorable COPs for the
household heat pumps.
Water and Sewage ReductionDuring the 8 months of the year
that all of the energy is being used,
the evaporative condenser is not
used, which results in an annual
water reduction of approximately
750,000 gallons (2.8 L) per year.
Electricity UseTable 1 summarizes BC Hydro’s elec-
trical consumption for the Westhills
Recreation Complex, including the
refrigeration and air conditioning
plant and all of the heat pumps, air
handlers, energy distribution pumps
and lighting. The ice rink refrigera-
tion system provides all heating and
cooling, dehumidification and hot
water for the entire 75,000 ft2 (6967
m2) complex, including the ice rink,
the 15,000 ft2 (1394 m2) of rented
office space and shop area, the res-
taurant and the bowling alley.
Almost every ice rink in North
America would have two energy
sources being consumed simultane-
ously, including electrical for the ice
plant, lighting, HVAC, etc., and fossil
fuels for hot water, dehumidification,
building heating, etc.
The electrical consumption for the
Westhills ice rink is much lower than
a typical single 40,000 ft2 (3716 m2)
ice rink, and this modest amount
of energy is serving an indoor and
outdoor rink with a skating trail, in
addition to providing all of the heat-
ing, air conditioning, hot water and
dehumidification requirement for a
75,000 ft2 facility (6967 m2).
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 58 8
PRODUCTS
PRODUCT SHOWPLACETo receive FREE info on the
products in this section, visit
the Web address listed below
each item or go to
www.ashrae.org/freeinfo.
A Control Valves With ThermostatSpartan Peripheral Devices, Vaudreuil, QC,
Canada, offers a line of control valve pack-
ages with the company’s TE150 dual-output
modulating proportional plus integral (P+I)
room thermostat. The direct- or reverse-
acting devices feature internal or external
sensors and auto changeover input.
www.info.hotims.com/54426-151
Water HeatersMagnaTherm boiler/volume water heaters
from LAARS, Rochester, N.H., provide 95%
thermal efficiency and 5:1 turndown. The
boiler features the company’s VARI-PRIME
pump control, which seamlessly matches
boiler firing rate to pump flow.
www.info.hotims.com/54426-152
B Commercial Fume HoodThe new Model GRRS Fire-Ready Hood
from Greenheck, Schofield, Wis., functions
as a standard ventilation range hood with
the added capacity to suppress stove-top
fires. This helps to protect residential-style
appliances used in commercial settings.
www.info.hotims.com/54426-153
Unit HeatersTrane, Davidson, N.C., has upgraded and ex-
panded the Expanse line of gas unit heaters.
The heaters feature a tubular heat exchang-
er, designed to be more reliable and effi-
cient than the conventional clamshell style.
www.info.hotims.com/54426-154
BAS Control SystemThe ECLYPSE Connected System Controller
from Distech Controls, Brossard, QC,
Canada, is a modular and scalable platform
providing BACnet/IP, wired and wireless
IP connectivity. The system consists of a
control automation and connectivity server,
power supplies, and I/O modules.
www.info.hotims.com/54426-155
A
Control Valves With ThermostatBy Spartan Peripheral Devices
B
Commercial Fume HoodBy Greenheck
Energy Management SystemThe Specified Comfort Energy Management System from Specified Controls, Indianapolis, is an integrated energy management system that enables multiple thermostats, lighting and load sensors, meters, fans and outlets to be wirelessly networked. www.info.hotims.com/54426-156
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 59 0
compact pipe covering fora safe and quick assembly for housing gas pipes, watercondensation discharge hoses and power lines.
Uponor’s PEX-a Pipe Support provides continu-ous support of PEX pipe for suspended piping applica-tions, enabling hanger spac-ing similar to copper or steelpipe. The 9-ft (2.7 m) support channels are available in arange of sizes and come with nylon-coated, stainless-steelstrapping to secure the pipe to the support.
SharkBite’s 2XL fittings are suitable for plumbing andhydronic heating applica-tions. These fittings combinecopper, CPVC, and PEX pipe in any combination withoutany tools, soldering, clamps, unions or glue. A range oftees, elbows and couplings are available.
PumpsKadant Johnson’s Liqui-
Mover condensate pump isan efficient way to pump or lift liquids and is availablewith either a float or float-free level control.
The Wilo Helix Excel is a vertical multistage pumpused in pressure boosting applications. Designed as apump-system, the hydrau-lics, mechanicals, controls
and electrical were designed and developed to fit together,eliminating any losses from using off-the-shelfcomponents.
Refrigeration/Process CoolingRefrigerant Solutions
Limited announced RS-70, a new GWP drop-in replace-ment refrigerant for R-22, designed to have the lowestpossible GWP with similar cooling capacity and coef-ficient of performance (COP) as R-22.
DunAn Microstaq, Inc.’s silQfloTM Silicon Servo Valveis a MEMS technology based microvalve suited for microand macro cooling applica-tions. It is an electronicallycontrolled proportional expansion device for lowcapacity cooling applications. For high capacity coolingapplications, it is a pilot valve.
Sensors, InstrumentsHoffman Controls offers
ECM Controllers in three models for controllingup to 16 ECM condenser fan motors from a singlecontroller.
Superior Signal Companyannounces the third Generation AccuTrak VPEleak detector. Featuring new internal circuitry and greatersensitivity, the detector is suitable for steam traps,
Left photo: A lively brazing demonstration taking place at the TurboTorch booth,. Right photo: (L-R) Kazuyuki Tamura, Tophio Sawada, and Takeshi Kobato examine the Z-Vent positive pressure approved piping from Z-Flex.
valve, and bearing wear applications.
The MaxiBlue reservoir sensor from Blue DiamondPumps offers an alterna-tive to stuck or sunken floatswitches that only run when condensate is produced. Itis suitable for environments that are both demandingand expensive to access for maintenance.
QTI Sensing Solutions developed the QTSSP andQTIP68 temperature sensor lines to avoid sensor failureduring the freeze/thaw cycles in refrigeration equipment.These waterproof sensors provide the reliability neededto overcome the temperature swings and moisture thatthermal cycles create.
The ThermoPro SeriesTP10 from Spire Metering Technology uses ultrasonictechnology to accurately measure temperature andflow. The clamp-on trans-ducers make installationsimple with no risk of leaking or contamination.
The Delta Controls eZNS-T100 network sensor com-bines temperature with humidity, CO2 and motionoptions into a single pack-age. The sensor features alow profile design, NFC com-munications, and LCD andcapacitive touch buttons.
The Sensaphone Sentinel
is a 12-channel remote moni-tor available with an optionalcellular modem for operation in locations where telephoneor internet service is unob-tainable. The unit allowsusers to monitor conditions such as temperature, humid-ity and water detection and receive alarms via phone,text and e-mail.
SniffIT X3® from Nolek isa handheld battery powered refrigerant leak detector. Thesmallest detectable levels of refrigerants with this detec-tor is 0.017 oz/year.
The HMS-1655 fume hoodmonitor from Triatek fea-tures a touchscreen with boldgraphics and menus. The home screen displays sashheight, face velocity, hood status, flow, temperature,time, and date. The product uses a closed-loop system tobetter regulate air entering and exiting the fume hood,and communicates with a face velocity flow sensor andsash position sensor to pro-duce truer fume hood read-ings with a higher degree of reliability.
Software, Mobile AppsFieldpiece Instruments
launches a new app, JobLink™, for wireless real- time measurements on iOSdevices. The app allows techs to view live measurements,
Products, From Page 13
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A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 59 2
SHOW COVERAGE
get insightful diagnostics, create professional lookingreports, and email findings to the office and customer.
Aquanomix introduces its new Symphony™ intel-ligent water quality and effi-ciency software system thatbridges currently separate building management dataof cooling tower water qual-ity and energy efficiency.The aggregated data of key performance indicators iscalculated into a single num-ber representing the overallefficiency of a cooling system called the Nexus Number™.
LUDECA’s tab@lign is a tab-let-based solution for pump-motor alignment which combines the PRÜFTECHNIKlaser measurement technol-ogy with tablet and smart-phone devices.
The Enceptia FabricationValue Pack is a set of add-on utilities to boost productivityand out-of-the-box capabili-ties with Autodesk fabrica-tion software. The Imperial Configuration Pack includespre-configured settings, templates and reports. ThePipe Rack Calculator aids pipe-hanger design and FabSync makes changing local and network settings easy.
Tune-Rite™ from Bacharach is an on-demandHVAC software program that helps contractors makemore thorough and efficient
for bonding a wide variety of insulation to galvanizedmetal substrates. It has the added benefit of having agreen label—requiring no explosion proof rooms—witha special non-flammable propellant, combined withextremely low VOC.
The Acrefine API-M typemodular rubber pad is designed to minimize vibra-tion and noise transmission from HVAC equipment tostructures. The pads can be cut to custom sizes eas-ily with a box knife and the through-bolt hole in eachmodule allows for easy installation. Applicationsinclude floor mounted mechanical equipment thatgenerate high frequency vibration like pumps, chill-ers, compressors, centrifugal fans, blower-coil units, ventsets, and low pressure pack-aged air-handling units.
service calls. It watches the analysis in real-time to deter-mine if the heating system being evaluated is operating in acceptable parameters and provides customized on-screen recommendations for tuning the system for opti-mum performance.
Firestone Building Products Company offers the “Build My Wall” app for metal and cavity wall sys-tems. The app is a searchable database of compatible wall panels and systems where users can view 3D renderings and obtain technical, instal-lation and fastening details.
Tools and AccessoriesMilwaukee Tool’s Black
Iron Press Jaws and Rings were designed for use on Viega MegaPress fittings. They provide a faster alter-native to threading and roll grooving to connect Schedule 5-40 Black Iron Pipe.
Klein’s Switch Drive Handle System allows users to alternate between a power tool and hand tool, mini-mizing the number of tools and saving space. The quick release mechanism secures any driver with a 0.25 in. (6.35 mm) hex shaft to con-vert an impact rated acces-sory to a powerful hand tool.
Carlisle HVAC Products offers the Non-Flam Travel-Tack, an aerosol adhesive
Valves, ActuatorsBray Commercial Division
launches the AutoTouchTerminal (ATT) line of pres-sure independent controlvalves. These valves fea-ture three point floatingand modulating actuators with and without failsafeprotection.
NitroVue Flow Indicatorfrom Uniweld Products features an easy to read flowindicator label and an adjust-able valve gives control overthe low flow of nitrogen gas during the brazing of coppertubing in AC and refrigera-tion systems.
HCi offers the TerminatorPICV (PressureIndependent Control Valve) for HVAC temperature con-trol. It is a combination, field adjustable, automatic balancevalve, and a full authority, equal percentage, tempera-ture control valve.
Left photo: Steven Cho (right) of EasyFlex looks on as Henry Gross (left) inspects some flexible pipe. Right photo: Product engineer Lennart Stahl (left forground) discusses thefeatures of Daikin’s VRF units with Paul Tseng.
Helge Jorgenson (left) and Ejner Kobbero (right) admire a 100-ton centrifugal chiller by Smardt Chiller Group.
www.info.hotims.com/54426-45
A S H R A E J o u R n A l a sh r a e . o r g M A R C H 2 0 1 59 4
CLASSIFIEDS
BUSINESS OPPORTUNITIES
ADIABATIC AIR INLET COOLING
EcoMESH Adiabatic Systems Ltd.
www.ecomesh.eu
EcoMESH Benefits
ADIABATIC AIR INLET COOLING
EcoMESH Adiabatic Systems Ltd.
www.ecomesh.eu
EcoMESH Benefits
ADIBATIC AIR INLET COOLING
EcoMESH Adiabatic Systems Ltd.
www.ecomesh.eu
EcoMESH Benefits
EcoMESH Adiabatic Systems Ltd.
www.ecomesh.euEcoMESH Adiabatic Systems Ltd.
www.ecomesh.euEcoMESH Adiabatic Systems Ltd.
www.ecomesh.eu
(1) (2) (3)
(4) (5) (6)
•Increased Capacity•Self Cleaning Filter•Shading Benefit
•No Water Treatment•Longer Compressor Life
•Increased Capacity•Self Cleaning Filter•Shading Benefit
•No Water Treatment•Longer Compressor Life
•Reduced Running Cost•Reduced Maintenance
•Easy Retrofit•Improved Reliability•Increased Capacity•Self Cleaning Filter•Shading Benefit
•No Water Treatment•Longer Compressor Life
Before After
•Reduced Running Cost•Reduced Maintenance
•Easy Retrofit•Improved Reliability•Increased Capacity•Self Cleaning Filter•Shading Benefit
•No Water Treatment•Longer Compressor Life
EcoMESH Benefits
Before After
StandardInstallation
EcoMESHAddition
WaterSpray
CoolerAir Intake
•Reduced Running Cost
•Reduced Maintenance
•Easy Retrofit
•Improved Reliability
•Increased Capacity
•Self Cleaning Filter
•Shading Benefit
•No Water Treatment
•Longer Compressor Life
•Self Cleaning Filter
•Shading Benefit
•No Water Treatment
•Longer Compressor Life
Improving the performance of Air Cooled Chillers, Dry Coolers and Condensersand Refrigeration Plants. EcoMESH is a unique mesh and water spray systemthat improves performance, reduces energy consumption, eliminates highambient problems, is virtually maintenance free and can payback in one coolingseason.
Improving the performance of Air Cooled Chillers, Dry Coolers and Condensersand Refrigeration Plants. EcoMESH is a unique mesh and water spray systemthat improves performance, reduces energy consumption, eliminates highambient problems, is virtually maintenance free and can payback in one coolingseason.
Improving the performance of Air Cooled Chillers, Dry Coolers andCondensers and Refrigeration Plants. EcoMESH is a unique mesh andwater spray system that improves performance, reduces energyconsumption, eliminates high ambient problems, is virtually maintenancefree and can payback in one cooling season.
FREE COOLING BENEFITSFREE COOLING BENEFITS
PASSIVE COOLINGPASSIVE COOLING
PCM ProductsPCM Productswww.pcmproducts.netwww.pcmproducts.net
FREE COOLING BENEFITSFREE COOLING BENEFITS
THERMAL ENERGY STORAGETHERMAL ENERGY STORAGE
..PCM ProductsPCM Productswww.pcmproducts.netwww.pcmproducts.net
BENEFITSBENEFITS
PCM ProductsPCM Productswww.pcmproducts.netwww.pcmproducts.net
THERMAL ENERGY STORAGETHERMAL ENERGY STORAGEPhase Change Materials between 8ºC(47ºF) and 89ºC(192ºF)release thermal energy during the phase change which releaseslarge amounts of energy) in the form
of latent heat. It bridges the gap between
energy availability and energy use and
load shifting
capability.
• EASY RETROFIT•LOW RUNNING COST• REDUCED MACHINERY• INCREASED CAPACITY
•GREEN SOLUTION• REDUCED MAINTENANCE• FLEXIBLE SYSTEM•STAND-BY CAPACITY
• No Running Cost
• Maintenance Free
• Cost Effective
• Easy Retrofit
• No Moving Parts
• Green Solution
+8ºC(47ºF)
+27ºC(80ºF)
• 15~25% Power Saving
• Maintenance Free
• Quick Payback
• Easy Retrofit
• Running Cost Saving
• Stand-by / Back-up
Thermal Energy Storage (TES) is the temporary storage of coldenergy for later use. It bridges the gap between energy availabilityand energy use.
EutecticTES within thecold store can beCharged using theexcess capacity duringoff-peak periods / over-night ambientconditions to shift the peak loads.
Eutectic TES is astatic system offering a full
stand-by capability in case of anymechanical failures and a
maintenance free back-up facility.
Thermal Energy Storage (TES) is the temporary storage ofthermal energy for later use, bridging the gap betweenenergy availability andenergy use.
Using conventionalsolar collectors one canprovide an under floorlow grade heating
utilising +27ºC (81ºF)Phase Change Material(PCM) containers andeliminate the for anyother heating source.PCM energy storageoffer energy / fuel freeheating solution.
PCMModules
Over-night cool energy is stored in the form of +20ºC (68ºF)Phase Change Material (PCM) containers and later the storedenergy is utilised to absorb the internal and solar heat gainsduring day-time for an energy free passive cooling / load shiftingsystem.
TubeICE
+20~24ºC(68~75ºF)
• No Running Cost
• Maintenance Free
• Cost Effective
• Easy Retrofit
• No Moving Parts
• Green Solution
(1) (2) (3)
(4) (5) (6)
Phase Change Materials between +8~20ºC(47~68ºF)can be simply charged using a free cooler over-night without theuse of a chiller and later the stored FREE energy can be used tohandle the day-time sensible
building loads.
•REDUCED MAINTENANCE
• FLEXIBLE SYSTEM
•STAND-BY CAPACITY
• LOWER INSTALLATION COST
• SIGNIFICANT ENERY SAVING
• GREEN SOLUTION
+13ºC(55ºF)
Over-night cool energy is stored in the form of +27ºC (80ºF)Phase Change Material (PCM) containers and later the storedenergy is utilised to absorb the internal and solar heat gainsduring day-time for an energy free passive cooling system.
•Easy Retrofit
•Heating even after sunset
•Uniform heating over 24h
•Flexible solution
•Simple control
•Cost effective solution
•Energy free solution
•Running cost savings
PCM ProductsPCM Productswww.pcmproducts.netwww.pcmproducts.net
THERMAL ENERGY STORAGETHERMAL ENERGY STORAGE
FREE COOLING BENEFITSFREE COOLING BENEFITSFREE SOLAR HEATINGFREE SOLAR HEATING
..
PCM ProductsPCM Productswww.pcmproducts.netwww.pcmproducts.net
THERMAL ENERGY STORAGETHERMAL ENERGY STORAGE
ENERGY STORAGE BENEFITSENERGY STORAGE BENEFITS
COLD STORAGE LOAD SHIFTINGCOLD STORAGE LOAD SHIFTING
www.pcmproducts.netwww.pcmproducts.net
Cells
FOR RENT
HVAC ENGINEERSAll levels. JR Walters Resources, Inc., specializing in the placement of technical professionals in the E & A field. Openings nationwide. Address: P. O. Box 617, St. Joseph, MI 49085-0617. Phone 269-925-3940. E-mail: [email protected]. Visit our web site at www.jrwalters.com.
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FineHVAC - HVAC Design HVAC Loads (Ashrae 2013), Chilled and Hot Water piping, Airduct Sizing, Psychrometric Analysis (includes also design for Merchant and Naval Surface Ships - Ashrae ch. 13.1 & 13.3).
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ASHRAE Journal Classified AdsThe Foremost Medium for Reaching Engineering Professionals
To place an ad contact: Vanessa Johnson
Advertising Production & Operations Coordinator
1791 Tullie Circle NEAtlanta, GA 30329
Phone: 678-539-1166Fax: 678-539-2166
Email: [email protected]
A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 59 6
ADVERTISING SALESASHRAE JOURNAL
1791 Tullie Circle NE | Atlanta, GA 30329 (404) 636-8400 | Fax: (678) 539-2174
www.ashrae.orgGreg Martin | [email protected]
Associate Publisher, ASHRAE Media Advertising Vanessa Johnson | [email protected]
Advertising Production Coordinator
NORTHEASTNelson & Miller Associates – Denis O’Malley; Jack O’Malley5 Hillandale Ave., Suite 101Stamford, CT 06902(203) 356-9694 | Fax (203) [email protected]
SOUTHEASTMillennium Media, Inc. – 590 Hickory Flat RoadAlpharetta, GA 30004Doug Fix (770) 740-2078 | Fax (678) 405-3327Lori Gernand (281) 855-0470 | Fax (281) [email protected]; [email protected]
EASTERN CANADANelson & Miller Associates – Denis O’Malley; Jack O’Malley5 Hillandale Ave., Suite 101Stamford, CT 06902(203) 356-9694 | Fax (203) [email protected]
OHIO VALLEYLaRich & Associates – Tom Lasch512 East Washington St.Chagrin Falls, OH [email protected](440) 247-1060 | Fax (440) 247-1068
MIDWESTKingwill Company – Baird Kingwill; Jim Kingwill664 Milwaukee Avenue, Suite 201Prospect Heights, IL 60070(847) 537-9196 | Fax (847) [email protected]; [email protected]
SOUTHWESTLindenberger & Associates, Inc. – Gary Lindenberger; Lori Gernand7007 Winding Walk Drive, Suite 100 Houston, TX 77095(281) 855-0470 | Fax (281) [email protected]; [email protected]
WESTLaRich & Associates – Nick LaRich, Tom Lasch512 East Washington St.Chagrin Falls, OH [email protected]@larichadv.com(440) 247-1060 | Fax (440) 247-1068
KOREAYJP & Valued Media Co., Ltd – YongJin ParkKwang-il Building #905, Dadong-gil 5 Jung-gu, Seoul 100-170, Korea+82-2 3789-6888 | Fax: +82-2 [email protected]
CHINA, HONG KONG & TAIWANChina Business Media – Sean Xiao6-310 Xinchao No.162 Liaoyuan RoadFuzhou, Fujian, China86 186 5099 [email protected]
INTERNATIONALSteve Comstock(404) 636-8400 | [email protected]
RECRUITMENT ADVERTISING AND REPRINTSASHRAE – Greg Martin(678) 539-1174 | [email protected]
Advertisers Index/Reader Service InformationTwo fast and easy ways to get additional information on
products & services in this issue:
1. Visit the Web address below the advertiser’s name for the ad in this issue.2. Go to www.ashrae.org/freeinfo to search for products by category or company name. Plus, link directly to advertisers’ Web sites or request information by e-mail, fax or mail.
Company PageWeb Address
Company PageWeb Address
Company PageWeb Address
*Regional
AAON, Inc .........................................................29info.hotims.com/54426-2
Aerionics, Inc./Macurco .................................85info.hotims.com/54426-3
AHR Expo Orlando 2016 .................................91info.hotims.com/54426-55
Air-Conditioning, Heating, and Refrigeration Institute ............................................................61info.hotims.com/54426-4
A-J Mfg Co. Inc ...............................................80info.hotims.com/54426-5
ASHRAE Webcast ...........................................87info.hotims.com/54426-1
ASHRAE District Guides ................................54info.hotims.com/54426-60
*ASHRAE Hospitals.........................................53info.hotims.com/54426-61
Belimo Aircontrols USA ..................................71info.hotims.com/54426-6
British Columbia Institute of Technology ...54info.hotims.com/54426-7
Captiveaire .......................................................43info.hotims.com/54426-8
Captiveaire .......................................................11info.hotims.com/54426-9
Carrier Corp......................................................67info.hotims.com/54426-10
Chil-Pak ............................................................46info.hotims.com/54426-11
ClimaCool Corp. ...............................................15info.hotims.com/54426-12
Climaveneta S.p.A. ..........................................83info.hotims.com/54426-13
Daikin North America LLC ............... 2nd Cvr-1info.hotims.com/54426-14
Data Aire .....................................................24-25info.hotims.com/54426-15
Distech Controls ..............................................69info.hotims.com/54426-16
Dwyer Instruments .........................................60info.hotims.com/54426-17
EBTRON ...................................................3rd Cvrinfo.hotims.com/54426-18
Goodway Technologies ...................................37info.hotims.com/54426-20
Greentrol Automation Inc. .............................55info.hotims.com/54426-19
Heat Pipe Technology Inc ..............................12info.hotims.com/54426-21
ISIB....................................................................89info.hotims.com/54426-22
LTG Incorporated .............................................37info.hotims.com/54426-23
Messe Frankfurt-ISH China ..........................63info.hotims.com/54426-57
Mestek/KN Series ...........................................23info.hotims.com/54426-24
Mestek/RBI Water Heaters .............................9info.hotims.com/54426-25
Mestek/Xcelon ................................................51info.hotims.com/54426-26
METALAIRE ......................................................19info.hotims.com/54426-27
Metraflex ..........................................................38info.hotims.com/54426-28
*Mitsubishi Electric Sales Canada, Inc ......53info.hotims.com/54426-50
Munters Corp ..........................................4th Cvrinfo.hotims.com/54426-29
Munters Corp ...................................................21info.hotims.com/54426-30
Nexus Valve ......................................................76info.hotims.com/54426-31
Onicon, Inc .......................................................86info.hotims.com/54426-32
Ontrol .................................................................46info.hotims.com/54426-33
Parker Boiler Co. .............................................75info.hotims.com/54426-34
Performance Aire ............................................56info.hotims.com/54426-35
Petra Engineering ...........................................57info.hotims.com/54426-36
Pittsburgh Corning ..........................................10info.hotims.com/54426-56
Reliable Controls ...............................................2info.hotims.com/54426-37
Renewaire, LLC ................................................77info.hotims.com/54426-38
Rotor Source, Inc. ...........................................75info.hotims.com/54426-39
Rotronic Instrument Corp ..............................84info.hotims.com/54426-40
Schneider Electric ............................................5info.hotims.com/54426-41
Shortridge Instruments Inc ...........................56info.hotims.com/54426-42
Soler & Palau USA, Inc ..................................88info.hotims.com/54426-53
Southland Industries ......................................62info.hotims.com/54426-43
Specific Systems .............................................82info.hotims.com/54426-44
Taco....................................................................81info.hotims.com/54426-51
Taco....................................................................33info.hotims.com/54426-52
Tate Access Floors, Inc ..................................93info.hotims.com/54426-45
Tekleen Automatic Filters Inc .......................13info.hotims.com/54426-46
Thybar Corp ......................................................13info.hotims.com/54426-47
Titus ...................................................................41info.hotims.com/54426-58
Trane ..................................................................31info.hotims.com/54426-48
Unilux Advanced Mfg, LLC.............................32info.hotims.com/54426-49
EBTRON, Inc. |1663 HWY 701 S., Loris, S.C. 29569 | Internet: EBTRON.com | Phone: 800 2 EBTRON | email: [email protected]
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