This article describes the minimum requirements for factory assembled air cooled reciprocating water chillers including compressor motor, motor starter, lubrication system, evaporator, condenser, controls, and interconnecting piping and wiring.
How Does A Chiller Work?
An air–cooled condenser uses ambient air to cool and condense the hot refrigerant gas back down to a liquid. It can be located inside the chiller or can be remotely located outside, but ultimately it rejects the heat from the chiller to the air. Resource by ThermalCare.
Air Cooled Reciprocating Water Chillers
Submittals
Product data shall include refrigerant; rated capacities; shipping, installed, and operating weights; certified dimension drawings, piping connections, furnished specialties; and accessories for each model indicated.
Shop Drawings:
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- Wiring diagrams indicating power, signal and control wiring. Wiring diagrams shall differentiate between manufacturer installed and field installed wiring.
- Access requirements around other work, including working clearances to mechanical controls and electrical equipment.
Certification of performance according to ARI 550.
Operation, installation and maintenance data shall be submitted for air-cooled reciprocating chillers to including operation and maintenance manuals.
Quality Assurance
- Electrical components, devices, and accessories shall be listed and labeled as defined in NFPA 70, Article 100, by a testing agency acceptable to authorities having jurisdiction, and marked for intended us.
- Chiller design, construction, leak testing, and installation shall comply with ASHRAE.
- Chillers shall comply with ASME BPVC: Section VIII, for construction and testing evaporator and condenser pressure vessels. Chillers shall be stamped with an ASME labe
- Chillers shall comply with UL 19.
- Chillers shall comply with NFPA.
- Chiller heat exchangers shall be tested and inspected in accordance with ASME BPVC: Section VIII, Division 1.
- Chillers shall be rated in accordance with ARI 5.
Casing
Exterior casing shall be manufacturer’s standard equipment casing coated with corrosion resistant exterior finish and with removable doors or panels for service and inspection.
Compressors
Compressors shall be hermetic or serviceable hermetic with multiple cylinders, lubrication system, crankcase heater, suction and discharge line service valves, mounted on vibration isolators.
Chiller shall be come with a full operating charge of non CFC refrigerant and oil.
Liquid Cooler
Cooler shall be direct expansion, shell and tube design with refrigerant in tubes, water in shell, and with removable carbon steel heads and baffle to ensure oil return.
Tubes shall be seamless copper expanded into tube sheets.
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- a. Internal finish shall be smooth or enhanced.
- b. Refrigerant working pressure shall be 2070 kP
- Water side working pressure shall be 1040 kPa.
Insulation shall be factory applied to evaporator, suction lines, and other surfaces where condensation might occur, with 19 mm thick, flexible elastomeric insulation.
Evaporator heater, when required, shall be a factory installed electric heater with capacity to protect evaporator to -29° C ambient temperature.
Refrigerant Circuit Accessories
Refrigerant circuits shall be provided with each of the following accessories:
a. Suction and discharge shutoff valves
b. Refrigerant charging connection
c. Hot gas muffler
d. Solenoid valve in liquid line
e. Filter/dryer with replaceable core
f. Sight glass and moisture indicator in liquid line
g. Pressure relief valve
h. Thermal expansion valve
i. Electronic expansion valve
Refer to SES H03-C01 for refrigeration specialty requirements.
Condenser
- Condenser coils shall be seamless copper tubing mechanically jointed to copper or aluminum fins.
- Condenser coils shall be factory tested for leaks to minimum test pressure of 2930 kPa.
- Coil grilles shall be louvered, galvanized steel mesh.
- Fans shall be direct drive, statically and dynamically balanced, with fan guard
- Fan motors shall be three phase with integral overload protection and permanently lubricated bearing
Control Panel
Control panel shall be manufacturer’s standard microprocessor-based chiller controls; unit or remote mounted, and factory wired with a single-point power connection and separate control circuit.
Status display shall include the following conditions:
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- a. Date and time
- b. Operating or alarm status
- c. Operating hours.
- d. Entering-chilled-water temperature
- e. Leaving-chilled-water temperature
- f. Evaporator refrigerant temperature
- g. Entering-condenser-water temperature
- h. Leaving-condenser-water temperature
- i. Evaporator pressure
- j. Condenser pressure
- k. Electronic expansion valve position
- l. Control set points
Control functions shall include the following:
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- Manual or automatic startup and shutdown time schedule
- Leaving chilled water temperature reset from entering chilled water temperature
- Electric demand limiting through compressor lockout
- Anti-recycling timing out to prevent rapid compressor cycling
- Automatic lead lag switching
- Chilled water temperature reset based on outdoor air or space temperature
- Start and run during low ambient air temperature
The following conditions shall shut down chiller and require manual reset:
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- Refrigerant low pressure
- Evaporator low temperature
- Refrigerant high pressure
- Low oil flow or pressure
- No or low chilled water flow
- Control device failure
- Low over control voltage
- Compressor motor current overload protection
Vibration Control
Where chiller compressor is not internally isolated, vibration control shall be direct isolation (no base) and the following vibration isolators, as applicable:
a. Rubber mounts with minimum deflection of 6 mm for indoor installation
b. Rubber mounts, suitable for exterior installation with minimum deflection of 6 mm for exterior installation
c. Restrained spring isolators with minimum deflection of 19 mm for indoor installation
Restrained spring type, galvanized or epoxy coated for exterior installation with minimum deflection of 19 mm for exterior installation