Reproducibility of an Emulator-Type Assessment Method for the Evaluation of the Dynamic Performance of Air Conditioners

The operation of air conditioners in practice responds to thermal loads with variable or intermittent modulations of the compressor speed and the expansion valve opening according to the native control system. Consequently, standard performance ratings obtained at fixed compressor speed benefit from ease of applicability and strong reproducibility but are not representative of the performance of actual installations and may be misleading for guiding the development of commercial units. This study aimed to establish a new performance evaluation method that accounted for the native control of the system in response to given thermal loads. Accordingly, the "emulator-type testing facility"was developed by combining an emulator that could simulate arbitrary indoor and outdoor conditions and a performance testing facility using the air enthalpy method for dynamic measurement of the cooling capacity supplied by the air conditioner. The reliability of the equipment was estimated, and the soundness of the evaluation technique was confirmed. Subsequently, a round-robin test was conducted on the same air conditioning unit in a separate testing facility from a third-party organization to prove the reproducibility of the emulator-type testing methodology while considering the actual controllability of the air conditioner. As a result, consistent Coefficient of Performance (COP) results and differences of approximately 5% were achieved when the system was tested in different testing facilities under the same load and outdoor conditions. Accordingly, the reproducibility of the emulator-type dynamic performance evaluation results was verified.