Influence of measured and calculated values on energy efficiency evaluation of low temperature refrigeration conditioner in GB 21455-2019

According to GB 21455-2019 minimum allowable values of the energy efficiency and energy efficiency grades for room air conditioners, the cooling capacity and power input of variable frequency air conditioners under low temperature refrigeration condition can be obtained by optional tests, which leads to poor consistency of annual performance factor (APF). Through the theoretical analysis on the calculation formulas of cooling capacity and power input combined with tests, it is found that the APF of variable frequency air conditioner obtained by using the measured value is higher than that obtained by using the calculated value under low temperature refrigeration condition. Therefore, it is suggested that the test values should be used for low temperature refrigeration condition, so as to ensure the consistency of energy efficiency evaluation.