Experimental analysis of an R134a refrigeration system using POE/CuO nanolubricant

Recent research in nanofluid application in refrigeration systems emphasise heat transfer enhancement and energy consumption reduction. There are limited experimental studies on how nanoparticles influence compressor operating pressures and discharge temperatures. This research addresses this gap by experimentally investigating the impact of 10 nm CuO nanoparticles on the performance of an R134a vapour compression refrigeration system. Nanoparticles were dispersed in Polyolester (POE) oil at mass concentrations of 0.025% to 0.30%. Effects of nanoparticles on compressor suction and discharge pressures, pressure ratio, discharge temperature, refrigerating effect, compressor work, and coefficient of performance (COP) were studied. The results signified that CuO has minimal effect on compressor suction pressure while the discharge pressure decreased by up to 16.29%, indicating reduced friction at the piston-cylinder interface. Compressor’s discharge temperature was lowered by up to 16.54%, which potentially reduces oil breakdown. Refrigerating effect improved by up to 8.58% due to enhanced evaporator heat transfer and nucleation site formation. Compressor work reduced by up to 20.33%, which is attributed to improved lubrication and reduced frictional losses. System COP reached an improvement of 35.89% at 0.25% mass concentration, demonstrating a substantial increase in energy performance. These experimental findings demonstrate the potential of CuO nanolubricant as an energy efficiency solution in refrigeration systems.