Influence of electronic expansion valve on the performance of small window air conditioner retrofitted with R407C and R290

Abstract

The objective of this study is to investigate the influence of electronic expansion valve on the performance of window air conditioner retrofitted with R407C and R290. The window air conditioner applying the electronic expansion valve is tested by varying the compressor inlet superheat from 0 °C to 20 °C. The eco friendly refrigerant R407C has the similar thermodynamic properties as those of R22 with an exception of temperature gliding during the phase change at con-stant pressure. R290 is a hydrocarbon which also exhibits properties very close to R22 which enables this to be used as a potential alternative to R22. The elec-tronic expansion valve affords a precise, fast, and stable flow control for a wide range of flow rate due to its use of an electronic control method based on an ad-vanced control algorithm. The electronic expansion valve controls the refrigerant flow through the evaporator by means monitoring pressure and temperature at the outlet of the evaporator and hence it shows good overall performances com-paring the capillary tube system. The coefficient of performance of R290 is the maximum among the three refrigerants tested and also for all the three refrige-rants, the coefficient of performance is low at higher degree of superheat.