The Anthracite Chapter

NEWS May 2016

ASHRAE - Shaping Tomorrow’s Built Environment Today

2015-2016 OFFICERS & CHAIRS President: Rich Karns rkarns@sordoni.com (570) 287-3161 x210 President-Elect: Alyssa Procida alyssa.procida@irco.com (570) 821-4923 Vice-President Eric Turner eftdd@aol.com Treasurer: Jon Keller jon@jfohora.com (570) 342-7778 Secretary & Research Promotion Chair: Maxwell Tamasy mtamasy@smartwattinc.com (724) 797-4908 Board of Governors: Dan Mello: (570) 288-8759 Board of Governors & Student Activities Chair: Tracey Jumper tjumper@smartwattinc.com (570) 471-3480 Board of Governors & Chapter Technology Transfer Chair: Matt Archey, PE marchey@borton-lawson.com (570) 821-1994 x1257 Grassroots Government Activities Chair: A.J. Speicher, PE aspeicher@borton-lawson.com (570) 821-1994 x 303 Historian & Newsletter Editor: Walt Janus, PE wjanus@gpinet.com (570) 342-3700 x5915 Membership Promotion Chair: Gary Booth booth@epix.net (570) 814-0042 Research Promotion Co-Chair: Cory Lock clock@genairesys.com (215) 348-1497 Website Homepage Editor: Karl Grasso kgrasso@anemostat.com (570) 562-2778 Young Engineers in ASHRAE Chair: Walt Stout wstout@borton-lawson.com (570) 821-1994 x1512

President’s Message The May chapter meeting is the final opportunity for this session to attend one of our very informative technical presentations. This month’s presentation is on HVAC and Airborne Infectious Diseases. The presenter is Dr. William Bahnfleth, ASHRAE Presidential Member and Distinguished Lecturer. Let’s make Dr. Bahnfleth feel welcome by seeing that the May meeting is the largest attended meeting of the year. This month’s meeting will be joint with ASHE. Please be sure to make Dr. Bahnfleth and our ASHE colleagues know that we appreciate their attendance and support. This month’s theme is Past Presidents month. Please take the time to shake the hand of as many attending past Presidents as possible and thank them for the time and energy they expended to make the chapter what it is today. The annual Mark A. Hagan golf tournament will be held this year on June 21 at Blue Ridge Trail Golf Club. Jon Keller and his committee are planning a fun event, as always, and will be reaching out for hole sponsors and foursomes. Look for more information concerning this favored event in the next few weeks. On April 21 the Chapter hosted the ASHRAE national webcast of Making Net Zero Net Positive: Solving the Efficiency and Cost Paradox at Ruth’s Chris at the Mohegan Sun Casino. The event was well attended with over 30 people in attendance. A big Thank You goes out to our corporate sponsors, Blankin Equipment, Harsco and Riello, as well as to Matt Archey, PE, who spent countless hours planning this highly successful event. Continued on page 3

Chapter Website: http://anthracite.ashraechapters.org

ASHRAE ANTHRACITE CHAPTER MEETING

Tuesday May 17, 2016

HVAC and Airborne Infectious Diseases

Presented by

William Bahnfleth, PE Concern regarding the risk of hospital acquired infections and the effect of the built environment on epidemics of drug-resistant diseases is increasing. The well-educated designer and owner needs to understand the mechanisms by which infectious disease is transmitted indoors, the extent to which HVAC system characteristics affect probability of infection, available means for controlling risk with demonstrated effectiveness. These topics are presented and discussed using the ASHRAE Board of Directors-approved Position Document Airborne Infectious Diseases as a framework. Pertinent scientific knowledge about modes of disease transmission is reviewed, its practical implications for control are discussed, and the three HVAC-related control methods identified by the Position Document: ventilation, particulate filtration, and ultraviolet germicidal irradiation, are presented and compared. General recommendations for reducing risk are provided and knowledge gaps that need to be filled are identified. William Bahnfleth is Professor and Director of the Indoor Environment Center in the Department of Architectural Engineering at the Pennsylvania State University (Penn State) in University Park, PA, where he has been employed since 1994. Previously, he was a Senior Consultant for ZBA, Inc. in Cincinnati, OH and a Principal Investigator at the U.S. Army Construction Engineering Research Laboratory in Champaign, IL. He holds BS, MS, and PhD degrees in Mechanical Engineering from the University of Illinois, where he also earned an undergraduate degree in music (pipe organ performance), and is a registered professional engineer. At Penn State, Dr. Bahnfleth teaches undergraduate courses in HVAC fundamentals and controls and graduate courses in chilled water systems, hot water and steam systems, and indoor air quality. His research interests cover a wide variety of indoor environmental control topics, including chilled water pumping systems, stratified thermal energy storage, protection of building occupants from indoor bioaerosol releases, ultraviolet germicidal irradiation systems, and others. He is the author or co-author of more than 150 technical papers and 13 books and book chapters. He consults on the design of chilled water thermal energy storage systems and has been involved in more than 20 projects world-wide. Dr. Bahnfleth is a fellow of both ASHRAE and the American Society of Mechanical Engineers (ASME) and is also a member of the International Society for Indoor Air Quality and Climate (ISIAQ), the International Building Performance Simulation Association (IBPSA), Sigma Xi, the American Society for Engineering Education (ASEE), and the Society of Building Science Educators (SBSE). He has served ASHRAE in a variety of capacities, including Student Branch Advisor, Chapter Governor, Technical Committee and Standing Committee Chair, and as Director-at-Large, Vice President, Treasurer, and 2013-14 Society President. He is the recipient of a 1st place ASHRAE Technology Award, Transactions Paper Award, and Distinguished Service and Exceptional Service Awards.

A Certificate of Attendance will be available at the registration table

Location: Holiday Inn Wilkes-Barre – East Mountain 600 Wildflower Dr,, Wilkes-Barre, PA 18702 (570) 822-1011

Schedule: 5:00-5:45 p.m. Business Meeting (All are Welcome) 5:30-6:30 p.m. Social Hour (Cash Bar) 6:00-6:30 p.m. Program Registration 6:30-7:15 p.m. Dinner (Buffet) 7:15-8:30 p.m. Technical Presentation

Cost: $ 30.00 per person - FREE for Students

Only If You Are Planning to Attend Please Respond by NOON on FRIDAY May 13, 2016 to Walt Janus at (570) 342-3700 Ext. 286 or via e-mail at wjanus@gpinet.com

NEWS and Notes President’s Message, Continued

The Region III Chapters Regional Conference (CRC) is being held from August 18 through August 20 in Philadelphia. As usual, Thursday will be Technical Sessions, Friday will be family day with tours and other activities, as well as the Welcome Reception. Saturday will be general chapter operations and committee workshops and the Awards Luncheon. We encourage attendance by as many chapter officers, committee chairs and general members as possible. More information and the registration form is available at www.ashrae.org under Society Groups, Regions, Region III. Finally, as outgoing Chapter President, I would like to personally thank the Chapter Officers, Board of Governors and Committee Chairs and Members for their continued support of ASHRAE, and of our local Chapter. I also want to thank the Chapter membership that takes the time to attend most, if not all, of the Chapter meetings throughout the year. Our chapter remains strong year in and year out because of the commitment that you show by your attendance and participation. Good luck to the incoming Officers and Board. Let’s make the 2016-2017 session one for the record books! See you at the meeting.

Rich Karns ASHRAE Annual Conference

Registration is open for the ASHRAE Annual conference to be held this June in St. Louis. The 2016 Annual Conference Host Committee has been hard at work to make sure that this is the Conference you will remember, with plenty of opportunities to socialize, relax, see the sights, and of course, learn. “The technical sessions offer an excellent opportunity to learn the results of cutting edge research and the latest standards that affect the built environment.” Thomas Kuehn, Conference Program chair, said. “Topics include nearly every technology used in HVAC&R including alternative refrigerants, fire and smoke control, smart control systems and sources and efficient utilization of renewable energy. In addition, learn the personal and business skills necessary to become and remain a leader in our industry.” Our own John Karakash will be presenting a session on heating and cooling with woody biomass on Tuesday morning (Seminar 42). For more information or to register, please go to www.ashrae.org/stlouis.

Mark A. Hagan PE Memorial Golf Outing Scheduled for June 21st Details are set for the Chapter’s annual golf outing to be held at Blue Ridge Trail Golf Club in Mountaintop. Full details are included in this issue of the NEWS starting on page 5. Hope to see you there! Technology Corner The reprint article “Hydronic Heat Recovery in Healthcare” is included at the end of this month’s edition of the NEWS, and is courtesy of the ASHRAE Journal. You may submit articles for consideration to be included in future editions to CTTC chair Matt Archey.

More NEWS and Notes Chapter Officers Elected for 2016-17 Society Year The winners of last month’s Chapter elections were announced at the April meeting, as follows:

President – Alyssa Procida President Elect – Eric Turner Vice President – Matt Grasso

Secretary – Walt Stout Treasurer – Jon Keller

Board of Governors – Matt Archey, Joe Cottone, Rich Karns Congratulations and thank you for serving the Anthracite Chapter. Thank You We received the following note of thanks from Chapter past president Manish Patel for the donations many of you made through the Chapter in memory of his daughter Monica who passed away last year. (My apologies for not including this in the NEWS sooner.)

I recently found out that the ASHRAE Anthracite Chapter made a very sizeable and generous donation to Cancertacular in memory of Monica Patel this month. Please let the Board and all the Members know that I appreciate it very much. Be assured that your assistance will help many deserving children and families in NEPA and Central PA battling cancer and will assist them with everything from medical care not covered by insurance to living as normal a life as possible given their circumstances. Your support and thoughtfulness is very much appreciated by me because this is a cause that is very near and dear to my heart. I hope to see you all at an Anthracite Chapter meeting soon. Thank you and God Bless You All,

Region III CRC in Philadelphia This year’s Chapters Regional Conference will be held at the Philadelphia Sonesta Hotel on August 18th through 20th. The Philadelphia Chapter (celebrating its 100th anniversary this year) has planned a great event, and since it is nearby, we should all consider representing our Chapter and supporting the Region. As usual the technical sessions will be held on Thursday (economical PDH’s), the business meeting and welcome reception will be on Friday, and the Chapter workshops will be on Saturday. For full details, to register and to reserve a hotel room go to http://region3.ashraeregions.org/reg_3cd.htm. Post Job Openings in the NEWS Looking for qualified people to fill a position in your organization? You may post industry-related openings in the NEWS and on our website for a donation of $40 per month. For more information contact Walt Janus.

ASHRAE ANTHRACITE CHAPTER 2016 MARK A. HAGAN, P.E. MEMORIAL GOLF OUTING

TUESDAY, JUNE 21, 2016 Blue Ridge Trail G.C.

Once again, it's time to mark your calendar for the annual ASHRAE, Anthracite Chapter golf outing. This year, we will be playing Blue Ridge Trail. We will be using an 11:00 AM shotgun start with scoring being captain &

crew. PLEASE NOTE THAT COURSE REQUIRES SOFT SPIKES. THESE ARE AVAILABLE AT COURSE IF YOU NEED

THEM. Cost of golf and dinner is $100.00 per person. Dinner only cost is $50.00 per person. Please plan to arrive 30 to 45 minutes early to register, get your cart and hole assignment, as well as practice

putting or driving. Dinner will be at 6:00 PM, buffet style. For reservations, call Jon Keller (570) 342-7778 or email at jon@jfohora.com. Reservations will be confirmed

via email when payments are received, credit card payment available via phone (Note: transaction fee will apply). Payments may be made payable to “ASHRAE Anthracite chapter” and mailed to or Jon Keller, C/O Joseph F. O’Hora & Sons, Inc. 1400-02 N. Washington Ave., Scranton, PA 18509. All payments and registration are due June 10, 2016 – PLEASE INCLUDE A POINT OF CONTACT PER FOURSOME. This year we are soliciting hole sponsorships for the tournament in our chapter effort to support ASHRAE

research. Companies sponsoring a hole will pay $125.00 per hole. New permanent signs with sponsor names and company logo’s will be posted at each tee. Send your company logo to Walt Stout at wstout@borton-lawson.com by June 10, 2016. Your hole sponsorship is tax deductible and receipts are

available upon request. Directions: South from Wilkes-Barre, take I-81 South to Nuangola exit (#159). At stop sign, make a left turn, and proceed 3/10 of a mile to next stop sign. Make right turn and proceed 1 mile to stop sign. Make a left turn and proceed 1.8 miles. At Prospect Road make a right turn and go 1.3 miles. At the intersection (Country Club Drive), make a left turn. Clubhouse will be on your right. Coming West from Pocono/Allentown area, take I-80 West to exit #262, to Route 309. Take Route 309 North

approximately 1.5 miles. Make a left turn, there will be a sign pointing to get to Interstate 81; go straight down mountain 3.1 miles. Make a sharp left turn. Proceed 1.6 miles, then make a right turn into the development. Continue straight 7/10 of a mile. Clubhouse will be on your left. Traveling North or East, take I-81 North to exit #155 (Dorrance), make a right turn to “T” in road. Make a left turn, go 2.4 miles. Next make a sharp left turn and proceed 1.6 miles. Make a right turn into the development. Continue straight 7/10 of a mile. Clubhouse will be on your left. Call early for reservations. See you there. Course number: 570-868-4653.

2016 Mark A. Hagan, PE

Memorial Annual Golf Outing

When: Tuesday, June 21st, 2016 11:00 am Shotgun Start

Where: Blue Ridge Trail Country Club 260 Country Club Drive

Mountain Top, PA 18707

Cost: Golf & Dinner $100 / Per Person

Dinner Only $50.00 / Per Person

Hole Sponsor $125 / Hole

Singles and Foursomes are welcome!!

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

RSVP TO: PAYMENT TO:

Jon Keller ASHRAE Anthracite Chapter 570-342-7778 1400-02 N. Washington Ave jon@jfohora.com Scranton, PA 18509

REGISTRATION FORM: Name Company Telephone Email

Golf & Dinner $100.00 / each X ______ = $

Dinner Only $50.00 / each X ______ = $

Hole Sponsorship $125.00 / each X ______ = $

ASHRAE Research Donation $ X ______ = $

Total Enclosed $ X ______ = $ USD

(Please remit payment by Friday June 10th, 2016 including point of contact per foursome) (Credit card payment available – transaction fees may apply)

Thanks to Our Sponsors

The display of business cards in the NEWS recognizes the financial support of the Chapter by the individual or business and does not constitute an endorsement or recommendation by ASHRAE or the Anthracite Chapter.

Thanks to Our Sponsors

The display of business cards in the NEWS recognizes the financial support of the Chapter by the individual or business and does not constitute an endorsement or recommendation by ASHRAE or the Anthracite Chapter.

Thanks to Our Sponsors

The display of business cards in the NEWS recognizes the financial support of the Chapter by the individual or business and does not constitute an endorsement or recommendation by ASHRAE or the Anthracite Chapter.

ANTHRACITE CHAPTER NEWS Walt Janus, Editor c/o Greenman-Pedersen, Inc. 50 Glenmaura National Blvd, Suite 102 Scranton, PA 18505

ASHRAE MISSION

• To advance the arts and sciences of heating, ventilating, air conditioning and

refrigerating to serve humanity and promote a sustainable world.

ASHRAE VISION

• ASHRAE will be the global leader, the foremost source of technical and educational

information, and the primary provider of opportunity for professional growth in the arts

and sciences of heating, ventilating, air conditioning and refrigerating.

2014-15 Matt Archey 2005-06 Manish Patel 1996-97 Charlie Smith 1987-88 Ray Suhocki 2013-14 Matt Archey 2004-05 A.J. Lello 1995-96 Chuck Swinderman 1986-87 Jerry Peznowski 2012-13 Tracey Jumper 2003-04 Dennis Gochoel 1994-95 John Walker 1985-86 Lee Garing 2011-12 A.J. Speicher 2002-03 Phil Latinski 1993-94 Dennis McGraw 1984-85 Spence Martin 2010-11 Tom Swartwood 2001-02 Mike Moran 1992-93 Scott Harford 1983-84 Donald Brandt 2009-10 Brian Flynn 2000-01 Dennis Gochoel 1991-92 Dan Mello 1982-83 Rich Santee 2008-09 Eric Zanolini 1999-00 John Durdan 1990-91 Mark Hagen 1981-82 Bob Mugford 2007-08 Walt Janus 1998-99 Matthew Martin 1989-90 Paul Dreater 1980-81 Kerry Freeman 2006-07 John Havenstrite 1997-98 Dean Butler 1988-89 Bud Reilly

Ant

hrac

ite C

hapt

er

Pas

t-Pre

side

nts

ANTHRACITE CHAPTER 2015-2016 MEETINGS & EVENTS

Date Theme Program Speaker

Sept. 15 Membership/Bring-a-Buddy

Joint Meeting with AIA

Geisinger Clinic Tour / Building Performance Analysis for Building Performance Rating Tools

M. Dennis Knight*

Oct. 20 Research Promotion –

Donor Recognition

Heating Applications with Variable Refrigerant Flow (VRF) Technology

Phil Latinski

Nov. 17 Students/YEA Building Information Modeling (BIM) Michael Brown

December Family Night No Meeting --

Jan. 19 Research Promotion Hybrid Heating Plant Design Luke Wonnell

Feb. 16 Engineer’s Week

Joint Meeting with PSPE

Basic Electricity Theory and Safety for Non-EEs

Mark Rutkowski

Mar. 15 Nominating Night

Joint Meeting w/SMACNA Through-Penetration Firestop Systems Richard Walke

April 19 Students/Membership HVAC Control Strategies A.J. Speicher

April 21 ASHRAE Webinar Making Net Zero Net Positive:

Solving the Efficiency & Cost Paradox Panel

May 17 Past-Presidents

Joint Meeting with ASHE HVAC and Airborne Infectious Diseases Bill Bahnfleth**

June 21 Fun & Fellowship Mark A. Hagan, PE Memorial Golf Tournament --

Aug. 18-20 Chapters Regional Conf. 2016 Region III CRC - Philadelphia, PA --

*ASHRAE Fellow and Distinguished Lecturer **ASHRAE Presidential Member and Distinguished Lecturer

A S H R A E J O U R N A L a s h r a e . o r g J U N E 2 0 1 42 4

TECHNICAL FEATURE

Jeremy McClanathan, P.E., is senior energy analyst at CDi+Mazetti in Seattle. He is an ASHRAE certified Building Energy Modeling Professional and a Healthcare Facility Design Professional.

Swedish Issaquah, a 350,000 ft2 (32 500 m2) hospital located in Issaquah, Wash., uses a hydronic heat recovery system to achieve a 50% energy savings compared to an average hospital in the Pacific Northwest. After I wrote an article (June 2013 ASHRAE Journal) about the hospital last year, readers asked about using exhaust air for heat recovery in hospitals, and about comparing exhaust air for direct air-to-air heat recovery versus chilled water to recover heat from the exhaust air for use in a hydronic heat recovery system using a heat recovery chiller.

This article seeks to answer the questions I received,

describe the advantages of hydronic heat recovery, and

provide design considerations regarding hydronic heat

recovery design. While this article is meant to address

general concepts of heat recovery in health care, data

from Swedish Issaquah will be used for examples to

illustrate concepts.

For the purposes of this article, hydronic heat recovery

refers to building level hydronic systems (chilled water

and heating water systems). This should not be confused

with the hydronics of a runaround loop air-to-air heat

recovery system.

Heat demand in a hospital can be grouped into three

general categories; central ventilation heating, envelope

losses, and zone air tempering due to minimum airflow

requirements. Air-handling unit heating coils serve

central ventilation heating requirements, and zone level

heating coils serve both the envelope losses and zone air

tempering.

Many hospitals are served by 100% outdoor air sup-

ply systems with air-to-air heat recovery. Various

types of heat exchanger options recover heat from

outgoing exhaust air and transfer the heat to sup-

ply air, reducing demand on the AHU heating coils.

However, these systems only recover heat when ven-

tilation heating is required. For much of the year,

more energy is available in the exhaust air than can

be recovered by these methods. As was done for the

Swedish project, Chilled water cooling coils can be

placed in the exhaust air and used in conjunction

with a heat recovery chiller to recover the addi-

tional heat and apply it to the heating water system,

BY JEREMY MCCLANATHAN, P.E., MEMBER ASHRAE

Hydronic Heat Recovery In Health Care

J U N E 2 0 1 4 a s h r a e . o r g A S H R A E J O U R N A L 2 5

TECHNICAL FEATURE

allowing the additional heat to be used at zone level

heating coils.

The pie chart in Figure 1 shows the portions of annual

heating energy consumed at the AHU level and the zone

level for Swedish Issaquah, which is served by recir-

culating VAV AHUs with hot water terminal heating.

The data is taken from an energy model, but two years

of trend data from the operational building match the

modeled data quite well. As can be seen in the chart, the

majority of heat demand in the building is served by the

zone heating coils. The percentages shown in Figure 1 will

vary by system type, climate, and operation.

Energy modeling indicates that if the AHUs had been

100% outdoor air supply systems with 50% effective air-

to-air heat recovery, the amount of heating energy at the

AHU heating coils would have roughly

doubled to about 4% for this build-

ing. To get an idea of how this might

vary by type and climate, the weather

file was changed to Chicago and the

model was run with 100% outdoor air

supply with 50% effective heat recov-

ery, and with both VAV and constant

volumes systems. The highest per-

centage of energy ventilation heating

accounted for in any scenario was 8%,

and the ratio of ventilation heating

to terminal heating was similar in all

scenarios.

Zone heat demand was much larger

than the AHU heating coil demand, and the cause will be

present in all hospitals. Minimum ventilation require-

ments of hospitals dictate higher airflows than necessary

to meet space cooling loads for most spaces in a hospi-

tal. To not over-cool spaces, the air is tempered at zone

heating coils. This air tempering happens 24/7 and is

the single largest energy demand in most hospitals. To

use recovered energy to serve this zone heating demand

in a hot water reheat system, hydronic heat recovery is

necessary.

Advantages of Hydronic Heat RecoveryHydronic heat recovery recovers heat from internal

loads through a heat recovery chiller and applies the

recovered energy to the heating water system, allowing

the heat to be used anywhere. Figure 2 is a scatter plot

showing the annual hourly heating water, chilled water,

and domestic hot water (DHW) demand in the building.

Orange is heating water, red is DHW, purple is chilled

water, and blue is the amount of energy available in the

chilled water system if chilled water coils are used to

recover heat from exhaust and relief air.

The data in Figure 2 indicates that there is enough heat

from internal loads in the building to meet the heating

demand for a majority of the year. This is likely to be

true for many health-care projects, and for this reason

a hydronic heat recovery system may be a beneficial

solution.

Design ConsiderationsSome design issues to consider when designing a

hydronic heat recovery system are sources of energy

available, sizing of the heat recov-

ery chiller and additional heating

and cooling equipment, design and

reset temperatures. Next are some

examples of how these issues were

addressed in the example hospital

that have proven to work well in that

application.

Basic DescriptionThe hydronic heat recovery system

at Swedish consists of a 300 ton (1055

kW) heat recovery chiller, three 520

ton (1830 kW) water-cooled chillers,

six 3,000 MBH boilers, chilled water

(CHW) coils in all major exhaust airstreams, and a control

sequence that allows the AHU main CHW coils to recover

heat that would normally be relieved in economizer mode.

Refer to Figure 3 for a schematic diagram of the system.

Sources of EnergyThe heat recovery chiller is controlled by heating

demand. It rejects all of its heat to the heating water loop,

and gets the energy it needs from the chilled water (CHW)

loop. The first source of energy in the CHW loop are the

process loads. Examples of process CHW loads are fan

coils units serving spaces such as electrical and IDF rooms,

and water-cooled medical equipment such as CT Scan

and MRI machines. These loads are available year-round

and serve as a base load for the heat recovery chiller.

During times in which outdoor air temperatures are

warm enough, the second source of energy comes from

All Other Building Energy 60%

Air Tempering & Envelope Losses

(Air Terminal Heating)38%

Central Ventilation Heating (AHU Heating) 2%

FIGURE 1: Building energy consumption.

This article was published in ASHRAE Journal, June 2014. Copyright 2014 ASHRAE. Posted at www.ashrae.org. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. For more information about ASHRAE Journal, visit www.ashrae.org.

2 6 A S H R A E J O U R N A L a s h r a e . o r g J U N E 2 0 1 4

cooling at AHU cooling coils neces-

sary to meet supply air set point tem-

peratures. When AHU cooling is not

available, the third source of energy

are exhaust heat recovery coils. The

exhaust heat recovery coils consist of

normal CHW coils placed in exhaust

airstreams. These coils cool the out-

going exhaust air to provide the load

being called for by the heat recovery

chiller. These coils are only used when

heating demand exceeds genuine

cooling demand in the building. When

the heating demand exceeds the

cooling load and all the exhaust heat

recovery coils are full open, the last

source of energy the system will search

for is energy available from relief air of

AHUs operating in economizer mode.Temperatures

The heat recovery chiller operating efficiency is a func-

tion of the lift on the compressor. The lower the heating

water temperature and higher the CHW temperature,

the higher the heat recovery chiller operating efficiency.

Design temperatures were chosen to balance operating

efficiency of the heat recovery chiller with size and first

cost of CHW and heating water coils. The heating water

system was designed with a 120°F (49°C) supply and 100°F

(38°C) return temperatures. With a supply temperature

of 120°F (49°C), most air terminal reheat coils were two

row coils and only a few required three row coils. The

CHW system was designed using 42°F (6°C) supply tem-

perature to meet humidity requirements. To keep the

lift on the heat recovery chiller as low as possible without

dramatically increasing the size of equipment, the heat

recovery chiller was designed to supply 48°F (9°C) CHW.

Fan coil units serving process cooling loads were designed

using 48°F (9°C) CHW and a bypass valve was included so

the main chillers could be bypassed when no ventilation

cooling is required, and all process loads could be served

by the heat recovery chiller directly.

CommissioningA hydronic heat recovery system is highly interactive.

AHUs, chillers, boilers, and other components that oper-

ate independently in a traditional system may impact the

operation of each other in a hydronic heat recovery system.

If AHUs are operating in economizer mode, the DDC

system will calculate the appropriate mixed air tem-

perature required for the AHU cooling coil to meet the

load being called for by the heating water system. Then,

economizer operation will be over-ridden, the AHU will

mix return air with outdoor air supply to achieve the cal-

culated mixed air temperature, and the AHU cooling coil

will be used to extract the amount of energy necessary for

the heat recovery chiller to meet heating demand.

Equipment SizingThe heat recovery chiller was not sized to meet design

conditions. Instead, an energy model was used to pro-

duce the scatter plot shown in Figure 2 and the heat

recovery chiller was sized using a combination of aver-

age heating demand in the summer, spring, fall, and

available energy in the CHW system during winter.

The heat recovery chiller is controlled to meet heating

demand. It does not have the ability to reject heat any-

where except the heating water system. When cooling

demand exceeds heating demand in the building, three

variable speed water-cooled chillers serve the additional

cooling required. Because the water-cooled chillers have

lower condenser temperatures, they have the ability to

meet cooling demand much more efficiently. When win-

ter heating demand exceeds the amount of energy avail-

able in the CHW loop, six condensing boilers supple-

ment the heat recovery chiller to meet the load.

Line indicates the amount of energy available for heat recovery from the CHW loop when exhaust and relief air are used.

900

800

700

600

500

400

300

200

100

0J F M A M J J A S O N D

Load

(Ton

s)

10,800

9,600

8,400

7,200

6,000

4,800

3,600

2,400

1,200

0

Load

(MBH

)

CHWEnergy AvailableHWHW + DHW

FIGURE 2: Building hydronic hourly loads.

TECHNICAL FEATURE

A S H R A E J O U R N A L a s h r a e . o r g J U N E 2 0 1 42 8

For Swedish Issaquah, several itera-

tions of control sequence adjustments

were required during the year after

startup commissioning was complete

and the building was occupied for the

system to achieve optimum results.

It is recommended that a project

pursuing a similar system consider

planning for post occupancy commis-

sioning to make any necessary adjust-

ments for optimal operation.

ResultsTrend data from 2013 shows that

93% of heating energy was served

by the heat recovery chiller with an

average heating only COP of 4.0. The

energy use intensity (EUI) for the past

two years has been 112 kBtu/ft2·yr

(353 kWh/m2·yr), and the heat recov-

ery system saves the hospital approxi-

mately $120,000/yr. While EUI reduc-

tions similar to that seen at Swedish

Issaquah may likely be seen in any

hospital project that has an oppor-

tunity to design a similar system,

the economic benefits depend on

the local price of natural gas, electric

rates and demand charge structures.

Careful analysis using local utility

rates to determine project specific

economic benefits is recommended.

Existing BuildingsAlthough this article is focused

on new hospital projects, the gen-

eral concepts may be applicable

58°F Chilled Water Return

Variable Flow Chilled Water

Pumps

Chiller Bypass Valve

Heat Recovery Coils in Exhaust Systems (Used Only When Additional Heat is Required)

Chilled Water Coils in Air-Handling Units

Process Cooling Loads

41.5°F Chilled Water Supply

48°F Chilled Water Supply300 Ton Heat Recovery

Chiller – Dual Compressor Screw Machine

530 Ton Chiller – Variable

Speed Screw Machine

(3 Typical)

Pump (Typical)

3,000 MBH Condensing Boiler (6 Typical)

100°F Heating Water Return

Heating Coils in Terminal Units

150°F Boiler Supply(120°F Under Normal Operation

Variable Flow Heating

Water Pumps

120°F Heating Water Supply

Condenser Heating Capacity is 4,520 MBH

VFD

Cooler

Condenser

Heating Coils in Air-Handling Units

to differing degrees in existing hospitals. If the heating

water supply temperature in an existing building can be

reset low enough during summer months and moderate

conditions for a heat recovery chiller to operate (typically

130°F and maybe higher), then a heat recovery chiller

could potentially meet a significant portion of the heating

demand. If the existing system is served by constant air

volume AHUs, the amount of air tempering in the build-

ing would be significantly higher than the example used

in this article. Therefore, the potential savings from a

hydronic heat recovery system would also be significantly

higher.

ConclusionSubstantial energy is available within a hospital for heat

recovery. In many applications, it may be enough to meet

a majority of building heating demand. A hydronic heat

recovery system using a heat recovery chiller and exhaust

recovery coils offer significant energy savings compared

to traditional boiler heating systems, and in many areas of

the country also offer substantial economic savings.

VFD

FIGURE 3: Heat recovery system.

TECHNICAL FEATURE