238143 - AIR SOURCE UNITARY HEAT PUMPS.pdf

Renovation of Historical Building 4

Project #565 20 101 03-01-20

AIR-SOURCE UNITARY HEAT PUMPS

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SECTION 23 81 43

AIR-SOURCE UNITARY HEAT PUMPS

PART 1 - GENERAL

1.1 DESCRIPTION

A. This Section specifies electrically operated air-source unitary heat pumps.

B. Definitions:

1. Coefficient of Performance (COP) - Cooling: The ratio of the rate of heat removed to the rate of energy input in consistent units, for a complete refrigerating system or some specific portion of that system under designated operating conditions.

2. Coefficient of Performance (COP) - Heating: The ratio of the rate of heat delivered to the rate of energy input is consistent units for a complete heat pump system, including the compressor and, if applicable, auxiliary heat under designated operating conditions.

3. Energy Efficiency Ratio (EER): The ratio of net cooling capacity is

Btu/h to total rate of electricity input in watts under designated operating conditions.

4. Heating Seasonal Performance Factor (HSPF) - Total heating output of heat pump during its normal annual usage period for heating in Btu/h divided by total electric energy input in watts during the same period.

5. Seasonal Energy Efficiency Ratio (SEER) - Total cooling output of an air conditioner during its normal annual usage period for cooling in

Btu/h divided by total electric energy input in watts during the same period.

6. Air-Source Unitary Heat Pump: One or more factory made assemblies that normally include an indoor conditioning coil, compressor(s) and an outdoor refrigerant-to-air coil. These units provide both heating and cooling functions.

1.2 RELATED WORK

A. Section 01 00 00, GENERAL REQUIREMENTS: For pre-test requirements.

B. Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, and SAMPLES.

C. Section 01 91 00 – GENERAL COMMISSIONING REQUIREMENTS

D. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL

COMPONENTS: Seismic requirements for non-structural equipment.

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E. Section 23 05 11, COMMON WORK RESULTS FOR HVAC: General mechanical requirements and items, which are common to more than one section of

Division 23.

F. Section 23 05 93, TESTING, ADJUSTING, AND BALANCING FOR HVAC:

Requirements for testing, adjusting and balancing of HVAC system.

G. Section 23 08 00 – COMMISSIONING OF HVAC SYSTEMS: Requirements for commissioning, systems readiness checklists, and training.

H. Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC: Requirements for controls and instrumentation.

I. Section 23 23 00, REFRIGERANT PIPING: Requirements for field refrigerant piping.

1.3 QUALITY ASSURANCE:

A. Refer to specification Section 23 05 11, COMMON WORK RESULTS FOR HVAC

B. Comply with ASHRAE Standard 15, Safety Code for Mechanical

Refrigeration.

C. Comply with ASHRAE Standard 90.1, Energy Standard for Buildings except

Low-Rise Residential Buildings for cooling and heating performance requirements when tested in accordance with AHRI 340/360 and UL 1995.

D. Heating Performance shall conform to ASHRAE requirements when tested in accordance with AHRI 340/360 and UL 1995.

E. Comply with requirements in Section 13 05 41, SEISMIC RESTRAINT

REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS.

1.4 SUBMITTALS

A. Submit in accordance with specification Section 01 33 23, SHOP

DRAWINGS, PRODUCT DATA, and SAMPLES.

B. Manufacturer’s Literature and Data.

1. Air-Source Unitary Heat pump:

a. Split system

C. Certification: Submit, simultaneously with shop drawings, a proof of certification that this product has been certified by AHRI.

D. Performance Rating: Submit catalog selection data showing equipment ratings and compliance with required cooling and heating capacities EER and COP values as applicable.

E. Completed System Readiness Checklists provided by the Commissioning

Agent and completed by the contractor, signed by a qualified technician and dated on the date of completion, in accordance with the requirements of Section 23 08 00 COMMISSIONING OF HVAC SYSTEMS.

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1.5 APPLICABLE PUBLICATIONS:

A. The publications listed below form a part of this specification to the extent referenced. The publications are referenced in the text by the basic designation only.

B. Federal Specification (Fed. Spec.):

A-A-50502-1990..........Air-conditioner (UNITARY HEAT PUMP), AIR TO AIR

(3000 TO 300,000 BTUH)

C. Air-Conditioning Heating and Refrigeration Institute (AHRI) Standards:

DCPP-2008...............Directory of Certified Product Performance -

Applied Directory of Certified Products

270-2015................Sound Rating of Outdoor Unitary

Equipment340/360-2015 Commercial and

Industrial Unitary Air-Conditioning and Heat

Pump Equipment

D. Air Movement and Control Association (AMCA):

210-2016................Laboratory Methods of Testing Fans for

Aerodynamic Performance Rating (ANSI)

410-1996................Recommended Safety Practices for Users and

Installers of Industrial and Commercial Fans

E. American National Standards Institute (ANSI):

S12.51-2017.............Acoustics - Determination of Sound Power Levels of Noise Sources Using Sound Pressure -

Precision Method for Reverberation Rooms (same as ISO 3741:1999)

F. American Society of Heating, Refrigerating and Air-Conditioning

Engineers Inc (ASHRAE):

15-2019.................Safety Standard for Refrigeration Systems

(ANSI)

90.1-2016...............Energy Standard for Buildings except Low-Rise

Residential Buildings

2016 Handbook...........HVAC Systems and Equipment

G. American Society of Testing and Materials (ASTM):

B117-2018...............Standard Practice for Operating Salt Spray

(Fog) Apparatus

D4587-2019..............Standard Practice for Fluorescent UV-

Condensation Exposures of Paint and Related

Coatings

H. National Electrical Manufacturer’s Association (NEMA):

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ICS 1-2005..............Industrial Controls and Systems: General

Requirements

MG 1-2019...............Motors and Generators (ANSI)

I. National Fire Protection Association (NFPA):

90A-2018................Standard for the Installation of Air-

Conditioning and Ventilating Systems

J. Underwriters Laboratory (UL):

1995-2005...............Heating and Cooling Equipment

PART 2- PRODUCTS

2.1 UNITARY HEAT PUMPS, AIR TO AIR

A. Units shall comply with Fed Spec A-A-50502 Type II, (Split System) having remote outdoor section separate from indoor Section, Class 2, Non–DOE covered products (units with cooling capacity up to 300,000

Btu/hr.

1. Unitary heat pumps shall bear the United States Environmental

Protection Agency, Energy Star label and shall have a minimum

Heating Season Performance Factor (HSPF) of 8.2 (Type II – Split

System), and a minimum Seasonal Energy Efficiency Ratio (SEER) of

14.5 (Type II – Split System).

B. Applicable AHRI Standards: Units shall be listed in the corresponding

ARI Directory of Certified products shown in paragraph, APPLICABLE

PUBLICATIONS:

1. Air Source heat pump with capacity above 19KW (above 65,000 Btu/hr, Comply with AHRI 340/360.

C. Casing: Unit shall be constructed of zinc coated, 14-gage minimum galvanized steel. Exterior surfaces shall be cleaned, phosphatized, and finished with a weather-resistant baked enamel finish. Unit surfaces shall be tested 500 hours in a salt spray test in compliance with ASTM

B117. Cabinet panels shall have lifting handles and shall be water- and air-tight seal. All exposed vertical, top covers and base pan shall be insulated with 25-mm (1-inch) matt-faced, fire-resistant, odorless, glass fiber material. Surfaces in contact with the airstream shall comply with requirements in ASHRAE 62.1. The base of the unit shall have provisions for forklift and crane lifting.

D. Compressors: Compressors shall be direct-drive, hermetic scroll type with centrifugal type oil pumps. Motor shall be suction gas-cooled.

Internal overloads and crankcase heaters shall be utilized with all compressors.

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E. Refrigerant Circuit: A minimum of two circuits is required. Each refrigerant circuit shall have independent fixed orifice or thermostatic expansion devices, service pressure ports, and refrigerant line filter driers factory installed as standard. An area shall be provided for replacement suction line driers.

F. Evaporator and Condenser Coils: Internally finned, DN 10 (NPS 3/8) copper tubes mechanically bonded to a configured aluminum plate fin shall be standard. The evaporated coil and condenser coil shall be leak tested at the factory to 1378 kPa (200 psig) and pressure tested to

2756 kPa (400 psig). All dual compressor units shall have intermingled evaporator coils. Sloped condensate drain pans shall be provided.

G. Outdoor fans: Direct driven, statically and dynamically balanced, draw-through in the vertical discharge position. The fan motors shall be permanently lubricated and shall have built-in thermal overload protection.

H. Defrost Controls: A time initiated, temperature terminated defrost system shall ship with a setting of 70-minute cycle, with a choice of

50- or 90-minute cycle. Timed override limits defrost cycle to 10 minutes shall be available on units from 35- to 70-kW (10 to 20 tons).

Adaptive demand defrost shall be provided on units below 35 kW (10

Tons).

I. Unit Electrical

1. Provide single point unit power connection.

2. Unit control box shall be located within the unit and shall contain controls for compressor, reversing valve and fan motor operation and shall have a 50 VA 24-volt control circuit transformer and a terminal block for low voltage field wiring connections.

3. Safety Controls - High pressure, low temperature, and low-pressure safety switches shall be wired through a latching lockout circuit to hold the conditioner off until it is reset electrically be interrupting the power supply to the conditioner. All safety switches shall be normally closed, opening upon fault detection.

J. Operating Controls

1. Provide unit with factory supplied DDC control system.

2. Unit DDC Controller:

a. Unit controller shall include input, output and self-contained programming as needed for complete control of unit.

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b. Unit controller shall be BACnet compliant and utilize BACnet operating protocol.

c. Control system shall seamlessly interface with temperature control system as specified in Section 23 09 23, DIRECT DIGITAL

CONTROL SYSTEMS FOR HVAC without requiring gateways or any other interface devices.

d. All program sequences shall be stored on board in EEPROM. No batteries shall be needed to retain logic program. All program sequences shall be executed by controller 10 times per second and shall be capable of multiple PID loops for control of multiple devices. Programming of logic controller shall be completely modifiable in the field over installed BACnet LANs.

e. Temperature Control System Interface: Points shall be available from the unit controller for service access and display and/or control.

f. Space Temperature Sensor: The wall mounted sensor shall include occupied and unoccupied setpoint control, pushbutton unoccupied override, space temperature offset and space temperature indication. Refer to Section 23 09 23, DIRECT DIGITAL CONTROL

SYSTEM FOR HVAC for additional requirements.

2.2 CORROSION PROTECTION

A. Remote Outdoor Condenser Coils:

1. Epoxy Immersion Coating – Electrically Deposited: The multi-stage corrosion-resistant coating application comprises of cleaning

(heated alkaline immersion bath) and reverse-osmosis immersion rinse prior to the start of the coating process. The coating thickness shall be maintained between 0.6-mil and 1.2-mil. Before the coils are subjected to high-temperature oven cure, they are treated to permeate immersion rinse and spray. Where the coils are subject to

UV exposure, UV protection spray treatment comprising of UV-resistant urethane mastic topcoat shall be applied. Provide complete coating process traceability for each coil and minimum five years of limited warranty. The coating process shall be such that uniform coating thickness is maintained at the fin edges. The quality control shall be maintained by ensuring compliance to the applicable ASTM Standards for the following:

a. Salt Spray Resistance (Minimum 6,000 Hours)

b. Humidity Resistance (Minimum 1,000 Hours)

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c. Water Immersion (Minimum 260 Hours)

d. Cross-Hatch Adhesion (Minimum 4B-5B Rating)

e. Impact Resistance (Up to 160 Inch/Pound)

PART 3- EXECUTION

3.1 INSTALLATION

A. Install heat pumps according to manufacturers printed instructions.

B. Install electrical and control devices furnished by the manufacturer but not specified to be factory mounted. All electrical work shall comply with Division 26 Sections.

C. Ductwork: Comply with requirements in Section 23 31 00, HVAC DUCTS AND

CASINGS.

D. Piping: Comply with requirements in Section 23 23 00, REFRIGERANT

PIPING.

3.2 STARTUP AND TESTING:

A. Perform startup checks according to manufacturer’s written instructions.

B. The Commissioning Agent will observe startup and contractor testing of selected equipment. Coordinate the startup and contractor testing schedules with the COR and Commissioning Agent. Provide a minimum of 7 days prior notice

C. Test controls and demonstrate its compliance with project requirements.

Replace damaged or malfunctioning controls and equipment and retest the equipment to the satisfaction of the CxA and COR.

D. Furnish test reports to the CxA and COR in accordance with specification Section 01 00 00, GENERAL REQUIREMENTS.

3.3 INSTRUCTIONS

Provide services of manufacturer’s technical representative for four hours to instruct VA personnel in operation and maintenance.

3.4 COMMISSIONING

A. Provide commissioning documentation in accordance with the requirements of Section 23 08 00 – COMMISSIONING OF HVAC SYSTEMS for all inspection, start up, and contractor testing required above and required by the

System Readiness Checklist provided by the Commissioning Agent.

B. Components provided under this section of the specification will be tested as part of a larger system. Refer to Section 23 08 00 –

COMMISSIONING OF HVAC SYSTEMS and related sections for contractor responsibilities for system commissioning.

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3.5 DEMONSTRATION AND TRAINING

A. Provide services of manufacturer’s technical representative for four hours to instruct VA personnel in operation and maintenance of units.

B. Submit training plans and instructor qualifications in accordance with the requirements of Section 23 08 00 – COMMISSIONING OF HVAC SYSTEMS.

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