All-condition measuring methods for field performance of room air conditioner

Room air conditioners (RACs) are used worldwide and have become one of the major energy consumers in buildings. Because the actual field performance directly affects the energy consumption, the actual performance of an RAC must be determined. The compressor energy conservation (CEC) method exhibits better adaptability to the existing field test methods. However, the refrigerant mass flowrate cannot be calculated accurately under two-phase suction conditions, which is common for current high-energy-efficiency RACs. Therefore, two all-condition field measurement methods based on the CEC and compressor efficiency (CE) methods are proposed, and the isentropic and volumetric efficiency under wet compression working conditions is predicted with data-driven models trained using a back-propagation neural network (BPNN). The accuracy verification indicates that the relative errors of the refrigerant flowrate and cooling/heating capacities of both methods are approximately within ±15%, which is sufficient for the field performance evaluation; in addition, the CEC–compressor volumetric efficiency (CVE) method performs better. Furthermore, the proposed methods are compared, and the accuracy of the dynamic conditions is analyzed to improve the calculation performance.