Design of a psychrometric coil testing facility for commercial size heat exchanger coils

Abstract

Abstract This paper presents the design of a testing facility at Oklahoma State University that enables performance testing of commercial-sized air to refrigerant heat exchanger coils. The closed-loop facility contains the necessary equipment to condition the air supplied to the tested coil. This includes the glycol conditioning system for the air conditioning heat exchangers, fans, electric heaters, and a steam humidification system. The design is compliant with multiple ASHRAE standards; the airflow measurement apparatus is compliant with both, Standard 41.2 (1987 and 2018). The test section's cross section is 2.13 m wide by 2.44 m tall with a maximum airflow rate of 3.78 m3 s−1. The thermal model presented in this paper predicts a maximum capacity of 80.9 kW for air heating coils (e.g. refrigerant condensers) at an air inlet temperature of 19.4 °C. The specified air flowrate and facility's maximum flowrate limit the capacity of air cooling (e.g. refrigerant evaporators) to a range of achievable values. The facility will operate over an air temperature range of −17.8 °C to 60 °C. Future work includes completion of construction of the facility including physical assembly, assembly of psychrometers, and commissioning of the developed facility control software.