Analysis of thermophysical properties and performance of nanorefrigerants and nanolubricant-refrigerant mixtures in refrigeration systems

Nanorefrigerants and nanolubricants have improved refrigeration system productivity. This research theoretically investigates Multi-Walled Carbon nanotubes (MWCNTs) and Copper Oxide (CuO) nanoparticles at volume fractions of 0.5, 1, and 2% in R152a and R134a refrigerants with Polyester (POE) lubricant. Thermophysical characteristics and COP will be examined. As volume concentration increases, thermal conductivity, density, and viscosity enhance, while specific heat capacity diminishes. However, after the nanoparticle volume concentration surpasses its optimal value, the specific heat capacity declines, potentially resulting in a reduction in cooling capacity. This inverse link suggests that in order to perform at one's best, a balance must be achieved. Despite this, nanorefrigerants and nanolubricant-refrigerants have improved COPs. Nanoparticle thermal conductivity is the main reason. R152a-based nanolubricant-refrigerants have greater COP values than R134a-based ones. R152a-MWCNTs-based nanorefrigerant had a maximum COP increase of 27.63% over R152a.In conclusion, nanorefrigerants made of R152a and Polyester (POE) lubricant are a good refrigeration option. Due to their high performance and environmental friendliness, these materials improve efficiency and energy consumption more than R134a.