ABSTRACT:

An experimental performance study of a vapour compression refrigeration system using R134a and a drop-in hydrocarbon refrigerant mixture of R290/R600a (50/50% by mass) was conducted with both a conventional condenser and an aluminium microchannel condenser. The experiments were performed at condenser temperatures of 44°C, 48°C, 55°C, and 58°C, while the evaporating temperature was varied from −10°C to 15°C in increments of 5°C (−10°C, −5°C, 0°C, 5°C, 10°C, and 15°C). The refrigerant charge was reduced by 10% for R134a and by 60% for the R290/R600a (50/50% by mass) mixture when the microchannel condenser was used instead of the conventional condenser. At a condenser temperature of 44°C and over the evaporating temperature range of −10°C to 15°C, the compressor power consumption decreased by 4.61% to 7.14% for R134a with the microchannel condenser compared with the conventional condenser. In contrast, the compressor power increased by 13.26% to 18.46% for the R290/R600a (50/50% by mass) mixture. The coefficient of performance (COP) increased by 5.89% to 15.78% for R134a and by 8.73% to 11.60% for the R290/R600a mixture when the microchannel condenser was employed. The refrigeration capacity of the system equipped with the microchannel condenser increased by 1.22% to 17.00% for R134a and by 3.07% to 20.65% for the R290/R600a (50/50% by mass) mixture compared with the conventional condenser. Similarly, the condenser heat rejection capacity increased by 6.74% to 18.33% with the microchannel condenser. Furthermore, the overall heat transfer conductance (UA) increased by 13.68% to 17.42% for R134a and by 4.34% to 26.5% for the R290/R600a mixture when the aluminium microchannel condenser replaced the conventional condenser.