Field performance of household room air conditioners in Yangtze River Region in China: Case studies

The field performance of room air conditioners (RACs) directly affects energy consumption. In this study, a longterm field test was conducted in six residential rooms in the Yangtze River Region, China. Using specially developed test equipment, the occupancy pattern, control level, and energy performance factors for constant frequency and inverter RACs were investigated. The field test results showed that the performance of RACs was dependent on the behavior of the occupants and the properties of the service space. The occupancy pattern for RACs was classified as part-time-part-space basis. The control level for constant frequency and inverter RACs indicated that their respective hourly operation ratios and compressor frequency distributions were quite different. Furthermore, based on the compressor energy conservation - compressor volumetric efficiency method, the part load and annual performance were calculated. The results showed that the energy efficiency of inverter RACs was relatively higher with a steady evaporating temperature and small capacity loss. In addition, the actual annual energy efficiency ratios were between 2.38 and 3.83, and the gap between laboratory tests and field test APF ranges from 8.4 to 32.0%, which shows a large difference in the cooling/heating seasonal performance efficiency compared with the laboratory tests.