Design and Construction of a Psychrometric Testing Facility for Commercial Scale Heat Exchanger Coils

Heat exchanger coils are used to provide heating and cooling in heating, ventilation, air conditioning and refrigeration (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. These design considerations could lead to more efficient systems, thereby reducing operating costs, as well as environmental impact.A psychrometric coil testing facility has been designed to facilitate performance testing of commercial-sized coils at Oklahoma State University. The closed loop airside subsystem of the facility contains heating/cooling coils, electric heaters, and a steam injection system used to control air conditions. Heat exchanger coils of up to 23 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 0F to 140F. The airflow measurement apparatus is compliant with ASHRAE Standard 41.2. The airside subsystem and its initial testing is completed. The conditioning and refrigerant loop subsystems are in the construction and design phase, respectively, as part of other master's projects. With the completion of these additional subsystems, performance testing of heat exchanger coils will commence. Data gathered from testing allows for the improvement of existing heat exchanger technology