Abstract: According to the standard GB 21455-2019 "Minimum allowable values of the energy efficiency and energy efficiency grades for room air conditioners", the energy efficiency rating index for fixed frequency heat pump type room air conditioners is APF (Annual Performance Factor). In order to improve the test quality, it is particularly important to evaluate the uncertainty of the APF. The air enthalpy method was used to test the performance of the air conditioners, and the calculation, measurement and uncertainty evaluation of APF were analyzed, and the relative expanded uncertainty of APF was 1.96%. Among them, and the uncertainty component introduced by the rated cooling capacity was the largest, accounting for 75.11%. Taking the rated cooling conditions as an example, the measurement parameters that had a greater impact on the rated cooling capacity were the indoor side inlet air bulb temperature and the indoor side outlet rheumatic bulb temperature, and the uncertainty components accounted for 51.99% and 36.42%, respectively.

Key words: Air enthalpy method, Sensitivity coefficient, APF, Uncertainty