S02 - Specs 238143.docx

03-01-23

SECTION 23 81 43

AIR-SOURCE UNITARY HEAT PUMPS

GENERAL

DESCRIPTION

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

A complete listing of common acronyms and abbreviations are included in Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

Definitions:

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.

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.

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.

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.

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.

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.

RELATED WORK

Section 01 00 00, GENERAL REQUIREMENTS.

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

Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

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

Section 23 08 00 COMMISSIONING OF HVAC SYSTEMS Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC.

Section 23 23 00, REFRIGERANT PIPING.

QUALITY ASSURANCE

Refer to specification Section 23 05 11, COMMON WORK RESULTS FOR HVAC Comply with ASHRAE Standard 15, Safety Code for Mechanical Refrigeration.

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 210/240 and UL 1995.

Heating Performance shall conform to ASHRAE requirements when tested in accordance with AHRI 210/240 and UL 1995.

SUBMITTALS

Submit in accordance with specification Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, and SAMPLES.

Manufacturer’s Literature and Data Including:

Air-Source Unitary Heat pump:

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

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

Completed System Readiness Checklists provided by the CxA 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.

APPLICABLE PUBLICATIONS

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. Where conflicts occur these specifications and the VHA standards will govern.

Federal Specification (Fed. Spec.):

A-A-505021990 Air-conditioner (UNITARY HEAT PUMP), AIR TO AIR (3000 TO 300,000 BTUH) Air-Conditioning Heating and Refrigeration Institute (AHRI) Standards:

Air Movement and Control Association (AMCA):

American National Standards Institute (ANSI):

S12.51-2012(R2020) Acoustics - Determination of Sound Power Levels of Noise Sources Using Sound Pressure - Precision Method for Reverberation Rooms (same as ISO 3741:1999) American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc. (ASHRAE):

American Society of Testing and Materials (ASTM):

National Electrical Manufacturer’s Association (NEMA):

National Fire Protection Association (NFPA):

90A-2021 Standard for the Installation of Air-Conditioning and Ventilating Systems Underwriters Laboratory (UL):

1995-2015 Heating and Cooling Equipment

AS-BUILT DOCUMENTATION

Comply with requirements in Paragraph ASBUILT DOCUMENTATION of Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

PRODUCTS

UNITARY HEAT PUMPS, AIR TO AIR

Units shall comply with Fed Spec A-A-50502 Type II, (Split System) having remote outdoor section separate from indoor Section, Class 1, "Department of Energy" (DOE) covered products (units with cooling capacity up to 65000 Btu/hr 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).

Applicable AHRI Standards: Units shall be listed in the corresponding ARI Directory of Certified products shown in paragraph, APPLICABLE PUBLICATIONS:

Air Source Unitary heat pumps with capacity less than 19 KW (65,000 Btu/hr), Comply with AHRI 210/240.

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

Casing: Unit shall be constructed of zinc coated 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 50-mm (2-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.

Filters: One inch, MERV 7, throwaway filter shall be standard on all units below 19kW (6 Tons). Filter rack can be converted to two-inch capability. Two inch, MERV 8, throwaway filters shall be factory supplied on all units above 19 kW (6 Tons).

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.

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.

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.

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.

Indoor Fan:

Provide direct-drive, Arrangement 4, plenum fan(s) equipped with variable-speed drives. Maximum fans in an array shall not exceed four.

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).

Unit Electrical Provide single point unit power connection.

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.

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.

Operating Controls Provide unit with low voltage electric controls.

Low voltage, adjustable room thermostat to control heating and cooling in sequence with delay between stages, compressor and supply fan to maintain temperature setting. Include system selector switch(heat-off-cool).

//Unit DDC Controller:

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

Unit controller shall be BAC net compliant and utilize BAC net operating protocol.

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.

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.

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

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.

Accessories:

Electric Heater: Constructed of heavy-duty nickel chromium elements. Staging shall be achieved through the unit control processor. Each heater shall have automatically reset high limit control. Heaters shall be individually fused from the factory and shall comply with NEC and CEC requirements. Power assemblies shall provide single point connection. Electric heat modules shall be listed and labeled by a national recognized testing laboratory acceptable to authorities having jurisdiction. Electric heater controls shall confirm the supply fan is operating before electric elements are energized. Operate electric heater in 2 stages when outdoor ambient is too low to maintain space thermostat setting with compressor operation.

Oversized Motors: Factory installed over sized motor shall be available for high-static application.

EXECUTION

INSTALLATION

If in the substantiated evaluation of the COR, the installation fails to meet the requirements of the construction documents with respect to function and maintainability, an installation is unsatisfactory to the COR, the Contractor shall correct the installation at no additional cost or time to the Government.

Install heat pumps according to manufacturers printed instructions.

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.

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

STARTUP AND TESTING

Perform startup checks according to manufacturer’s written instructions.

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 COR.

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

COMMISSIONING

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 CxA.

- - - E N D - - - 23 81 43- 9