As annual performance factor (APF) becomes the energy efficiency index of inverter air conditioners

the amount of working conditions to be tested for each air conditioner has greatly increased from one to five

which means that experiment-based maximization of the energy efficiency index may result in too heavy experimental tasks. This studyaims to introduce a method for maximizing the APF of an inverter air conditioner

which can calculate the maximum APF quickly according to a set of testing data. In this method

an APF explicit formula was deduced from complicated and implicit expressions in the Chinese Standards and was taken as the objective function for optimal calculation. Subsequently

the APF constraint equations were deduced according to the Chinese Standard and structural parameters of air conditioners and were taken as constraint conditions. Finally

an optimization algorithm is established for calculating the maximum APF and best combinations of capacity and energy efficiency of five working conditions. Moreover

an application example of a typical inverter air conditioner using the new method was provided

along with the operation steps

andthe value of APF increased by 6.37% in comparison with the originally measured value.