Experimental investigation of a bypass two-circuit cycle refrigerator-freezer with low GWP zeotropic refrigerants

Abstract

Based on the pursuit of lower temperatures and environmentally friendly refrigerants in domestic refrigerator-freezers, this paper investigates the performance of a hydrocarbon mixture R600/R290 in a bypass two-circuit cycle applied in −40 °C frost-free refrigerator-freezer. With the aim of achieving a temperature below −40 °C in the freezer compartment and saving energy consumption in the entire system, experiments are conducted to explore the optimal composition and charge of R600/R290. The results indicate that when the total charge of R290/R600 is 77 g and the mass fraction is 43 %/57 %, the freezer compartment can reach −40.6 °C and has a low daily energy consumption of 1.514 kW h/24h at the ambient temperature of 32 °C. In addition, the effect of fan voltage, which is used to characterize the airflow rate in the freezer compartment, on the system performance at different ambient temperatures is also studied. Under the premise that the charge of R290/R600 is 77 g and the mass fraction is 48 %/52 %, when the fan voltage is 7.5 V, the system daily energy consumption is the lowest. At this time, the system daily energy consumption at 25 °C and 32 °C ambient temperatures is 1.161 kW h/24h and 1.553 kW h/24h, respectively.

Keywords

• Domestic refrigerator-freezer
• Bypass two-circuit cycle
• -40 °C
• Zeotropic refrigerant
• Frost-free