significant changes to commercial mechanical and service...
TRANSCRIPT
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Connecticut Chapter of ASHRAE
Significant Changes to
Commercial Mechanical and Service Water Heating
Requirements of
2015 International Energy Conservation Code
2015 International Energy Conservation Code (2015 IECC)
Section C101.3 Intent
n Regulate design and construction of buildings
n for the use and conservation of energy
n over the life of each building.
Section C103.2 Information on Construction Documents
n Insulation material and their R-values n Fenestration U-factors and SHGCs n Area-weighted U-factor and SHGC calculations
n Mechanical system design criteria n Mechanical and service water heating system and
equipment types, sizes and efficiencies n Economizer description n Equipment and system controls n Fan motor horsepower (hp) and controls n Duct sealing, duct and pipe insulation and location n Lighting fixture schedule with wattage and control narrative n Location of daylight zones on floor plans n Air sealing details
n Building thermal envelope depiction 3
Commercial Energy Efficiency n Commercial building shall comply with ONE of:
1. ANSI/ASHRAE/IESNA Standard 90.1-2013 with Appendix G Excerpt
2. IECC envelope, mechanical systems, service water heating, electrical power and lighting systems requirements AND one additional efficiency option
3. IECC Total Building Performance where building energy cost ≤85% of standard reference design building.
n Chapter 5 Existing Buildings n Section 502 Additions n Section 503 Alterations
Additional Efficiency Package Options
n Buildings comply with at least one of 1. Efficient HVAC performance 2. Reduced lighting power density 3. Enhanced lighting control 4. On-site supply of renewable energy 5. Dedicated Outdoor air system
6. High-efficiency service water heating n Individual tenant spaces comply with:
n 1, 2, 3, 5, or 6 above n Unless entire building complies with 4 above
Code Requirements Comparison
Current vs Proposed Commercial Requirements spreadsheet at http://ctashrae.org/content.php?page=Codes
Equipment Performance n Unitary air conditioners and condensing units n Unitary and applied heat pumps n Packaged terminal air conditioners, package terminal heat pumps,
room air conditioners and room air-conditioner heat pumps n Single-packaged vertical air conditioners and single-package vertical heat
pumps n Warm air furnaces and combination warm air furnaces/air-conditioning units,
warm air duct furnaces and unit heaters n Gas- and oil-fired boilers n Electrically operated condensing units n Water chilling packages n Heat rejection equipment n Air conditioners and condensing units serving computer rooms n Heat transfer equipment n Refrigeration systems (equipment & enclosures)
HVAC System Controls n Thermostatic Controls n Off-hour controls for each zone
n Zone isolation n Snow- and Ice-melt system controls
n Freeze protection n Boiler temperature setback n Static pressure reset n VAV control before reheating, recooling or mixing n Supply air temperature reset n VAV ventilation optimization control (systems with DDC)
Fan Air Flow Control
n Required for: n ≥65,00 Btu/h on DX cooling systems n ≥¼ hp on chilled water & evaporative cooling
n ≥2 speeds with minimum speed ≤66% full speed n For DX & chilled water units n Capacity control of mechanical cooling based on space temperature n Low/minimum speed used during ventilation-only operation
n Speed modulation with minimum speed ≤50% full speed n For other DX and chilled water units n Low/minimum speed used during ventilation-only operation
n ≥2 speeds for use during air economizer operation
Economizers n On fan DX cooling units ≥54,000 Btu/h n On chilled water with system capacity less air
economizer capacity n ≥1,320,000 Btu/h for local water cooled systems n ≥1,720,000 Btu/h for local air cooled systems or district systems
n Total system capacity without economizers n ≤300,000 Btu/h per building or n ≤20% of air economizer capacity
n Design exceptions for water-side economizers serving computer rooms
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Economizer Fault Detection and Diagnostics (FDD) n Required for: (when equipped with economizer)
n Air-cooled unitary direct-expansion units n Variable refrigerant flow units
n Status indicators: n Free cooling available n Economizer enabled n Compressor enabled n Heating enabled n Mixed air low limit cycle active n Current value of each sensor
n Fault detection capabilities: n Air temperature sensor failure/fault n Not economizing when unit should be n Economizing when unit should not be n Damper not modulating n Excess outdoor air
Ventilation n Capability to reduce outdoor air to minimum required by IMC
n Demand controlled ventilation n Enclosed parking garage controls
n For garages (without heating or mechanical cooling) n ≥22,500 cfm total exhaust capacity n ≤1125 cfm/hp (garage area to motor nameplate hp)
n Automatic controls to stage fans or modulate average airflow to:
n ≤50% design capacity or n <20% occupied time or n As required to maintain acceptable levels
n Kitchen exhaust systems
Energy Recovery Systems Capability to: n Provide changes in
enthalpy ≥50% of difference between outdoor and return air, and
n Permit cooling with outdoor air where required
Exception for laboratory fume hood systems with requirements
Air System Design
n Each system with total fan system motor nameplate horsepower >5 hp
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Motor nameplate horsepower • Fan brake horsepower indicated on construction documents • Selected motor shall be not larger than first available motor size
greater than: • 1.5 times fan bhp, for fans <6 bhp • 1.3 times fan bhp, for fans ≥6 bhp • Or complying with option 1
• Does not apply to motors ≤1 hp
Air System Design
n For fans >5 hp (single fan nameplate hp or combined nameplate hp for multiple fans operating in series or parallel) n ≥67 Fan Efficiency Grade (FEG) n Total efficiency of fan
At design point of operation within 15 percentage points of maximum total efficiency of fan
n Fractional hp motors (≥1/12 hp and <1 hp)
n Electronically commutated or n ≥70% efficient n Exception for motors in fan coils/terminal units that only provide
heating or in rated space conditioning equipment
Hydronic System Design n Systems ≥500,000 Btu/h in design output capacity
n Automatically reset supply-water temperature n Automatically vary fluid flow on systems with
n ≥10 hp motor capacity n ≥3 control valves or other flow reducing devices
n Automatically vary pump flow on n Chilled-water systems n Heat rejection loops serving water-cooled unitary equipment n ≥10 hp combined motor capacity
n Minimum boiler turndown ratio n 3 to 1 for boilers ≥1,000,000 and ≤5,000,000 Btu/h n 4 to 1 for boilers >5,000,000 and ≤10,000,000 Btu/h n 5 to 1 for boilers >10,000,000 Btu/h
Heat Rejection Systems n Speed control on each fan motor ≥7.5 hp
n Fan speed control capabilities n ≤⅔ full speed n Automatically changes to control leaving fluid temperature
n Multiple-cell heat rejection equipment with variable speed control
n Operate maximum number of fans allowed to comply with manufacturer’s requirements for all system components
n All fans operate at same speed
n Open-circuit cooling tower flow turn down n Cells run in parallel with the larger flow:
§ Produced by smallest pump at its minimum expected flow rate, or § At 50% of design flow rate for the cell
HVAC System Construction
n Duct & plenum insulation n ≥R-6 insulation located in unconditioned spaces n ≥R-12 insulation where located outside building n ≥R-12 insulation separating duct or plenum from
exterior or unconditioned or exempt space
n Duct testing n ≤4.0 air leakage rate for high pressure duct
HVAC System Construction
n Piping insulation
n Heating outside a building n Radiant heating system controlled by occupancy
sensing device or timer switch
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Service Water Heating n Equipment performance n High input-rated systems (≥1,000,000 Btu/h)
n Temperature controls n Heat traps n Pipe insulation
n Use HVAC pipe insulation requirements n First 8’ on inlet & outlet pipe of heated water tank or to heat trap n On heat traced pipe
n Automatic or readily accessible manual control on circulating pump or heat trace shut-off when limited hot water demand
Service Water Heating
n Efficient heated water supply piping n Maximum flow rates n Maximum pipe length
n Allowable pipe length method § From nearest source to fixture § Largest size determines length
n Allowable pipe volume method § From nearest source to fixture § Water volume determination
n Circulating and maintenance systems
Section C408
System Commissioning n Mechanical systems commissioning and
completion requirements n Prior to passing final mechanical inspection
n Registered design professional shall provide § Evidence of mechanical system commissioning § Evidence of completion
n Construction document notes to clearly indicate commissioning & completion requirements
n Documents n Given to owner & available to building official
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Section C408
System Commissioning n Exception:
1. Total mechanical equipment capacity in building: n <480,000 Btu/h cooling capacity, and n <600,000 Btu/h heating capacity
2. Systems serving n Dwelling units n Sleeping units in hotels, motels, boarding
houses, or similar units
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Section C408
System Commissioning n Commissioning plan n Functional performance testing n Preliminary commissioning report n Final commissioning report
n Functional performance tests results n Disposition of deficiencies including used or proposed corrective measures n Functional performance test procedures
n Documentation n Record drawings n Operation Manuals n Maintenance Manuals n System balance reports
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