An experimental evaluation of the vapour compression plant performances in presence of R407C leaks using an electronic expansion valve

Abstract

Chlorofluorocarbons and hydrofluorocarbons (HFCs) used as working fluids in the vapour compression plants, have to be replaced by new substances because of their ozone depletion potential. Zeotropic mixture of HFCs refrigerants that are environment-friendly substances are often employed. The zeotropic mixtures with a large glide temperature could cause problems in the refrigeration control system when a leak occurs because their composition modifies. This paper presents a comparison of the energetic performances, in presence of leaks, when a thermostatic valve and an electronic expansion valve are used in a refrigeration plant, working with the zeotropic mixture designated as R407C (R32/R125/R134a 23/25/52% in mass)—this is the most suitable substitute of the HCFC22. The vapour leaks are simulated at the inlet of the evaporator and at the liquid receiver. Experimental results show that a good adaptability to mixture leaks is related to the electronic expansion valve, while better energetic performances are obtained using the thermostatic expansion valve as long as it is usable.