Design and Construction of a Psychrometric Coil Testing Facility for Commercial Size Heat Exchanger Coils
coils, psychrometrics, facility, loop, design
Heat exchanger coils are used to provide heating and cooling in HVAC&R equipment. Testing of coils is necessary to evaluate how design changes, such as refrigerant distributor, fin type, and circuitry, affect heat exchanger coil performance. A psychrometric coil testing facility has been designed to facilitate performance testing of commercial-sized coils at Oklahoma State University. The current status of the psychrometric coil testing facility will be discussed. The closed loop facility will contain various equipment to condition the air including heating/cooling coils, electric heaters, and a steam injection system. Heat exchanger coils of up to 20 nominal tons of cooling capacity can be tested in a 7 ft wide by 8 ft tall test section that can supply a maximum air flow rate of 8,000 CFM. With the initial chiller configuration, the facility will be able to operate over an air temperature range of 0°F (-17.8°C) to 140°F (60°C). It is planned to extend the operating envelope to -40°F (-40°C) with a high capacity low temperature chiller. The design phase of the structure is complete and the facility is currently under construction, while the coil conditioning loops are in the design phase. The design is compliant with multiple ASHRAE standards, including Standards 37 and 41.2 which aided in designing the airflow measurement apparatus and louvered air mixers, respectively. Future work includes completion of construction, selection of instrumentation, and development of a LabVIEW controls interface to be integrated upon tunnel completion.