Baseline testing of a variable-speed water-cooling Chiller according AHRI standard 550/590

Abstract

A new experimental test facility was designed to test vapor compression chillers of up to 145.9 refrigeration tons (approximately 513 kW). To implement such a large-capacity test facility in a university laboratory research environment, the system design is based on regenerative shell and tube heat exchangers. The capacity load on the chiller can be controlled via a bypass valve that allows a flow change over the internal heat exchangers. In addition to the internal sensors of the chiller, a variety of sensors in the system ensures a detailed recording of data as well as an automation of the test procedure.The test facility is constructed and commissioned to execute the performance according the AHRI Standard 550/590. The chiller has been tested in full load and part load rating conditions to achieve a characteristic performance line of the machine. Recorded data is averaged and evaluated according to the requirements of the AHRI standard. The results of the baseline testing and the data processing are presented in this paper. A detailed analysis of the outcomes allows a comparison with the manufacturer rated efficiency values.Finally, the potential instabilities of the test systems that caused problems during the test runs and their reasons are discussed, as well as possibilities to overcome them. The given ability of the test facility for a rapid change between different load conditions allows the arrangement of test cycles to investigate the performance degradation of the twin-screw chiller over time.