Abstract
In this paper, firstly the results of the partial thermal load performance tests of multi-type air-conditioners for buildings were shown. Tests were conducted by using the air-enthalpy method testing apparatus. Two types of air-conditioners, heat pump driven by electric motors (EHP) and that driven by gas engines (GHP), with a rated cooling capacity of 56 kW were tested. The coefficient of performance (COP) and the annual energy consumption measured by the above mentioned tests were closely compared with those predicted by JIS. In EHP,the measured COP indicates the maximum when the indoor thermal load is about 50% of the rated capacity, while COP in GHP decreases gradually as the thermal load is decreased. Based on these results, we examined the accuracies of COP and the annual energy consumption predicted by JIS. It was found that in both EHP and GHP the current calculating method prescribed in JIS could not duplicate the COP decrease that appeared under the low thermal load conditions. As a result, the annual energy consumption is seriously underestimated by JIS. The prediction errors of the annual energy consumption amounted to about 17% for EHP and 38% for GHP
