Nanomaterials and Eco‐Friendly Refrigerants in Vapor Compression System: A Review of Performance and Sustainability

ABSTRACT This review paper systematically investigates the role of nanomaterials and eco‐friendly refrigerants in enhancing the performance of vapor compression refrigeration systems. A comprehensive analysis of recent experimental studies on nano‐oils and nano‐refrigerants is presented, focusing on their thermophysical and tribological characteristics. Various mono and hybrid nanoparticles, such as Al 2 O 3 , CuO, TiO 2 , graphene, and CNTs, dispersed in compressor lubricating oils have been reviewed. Reported results indicate significant improvements in system performance, including an increase in the overall heat transfer coefficient by 8%–35%, a reduction in compressor power consumption by 5%–20%, an enhancement in coefficient of performance by 8%–30%, and improved lubrication characteristics. The addition of nanoparticles also results in better oil‐refrigerant miscibility, improved thermal conductivity, reduced frictional losses, and more stable compressor operation without requiring major system modifications. Furthermore, the use of low global warming potential (GWP), eco‐friendly refrigerants in combination with nanolubricants contributes to enhanced energy efficiency and environmental sustainability. This review highlights the influence of nanoparticle concentration, size, and type on system performance and identifies research gaps related to long‐term stability, compatibility, and environmental impact. The study concludes with recommendations for future research focusing on ultra‐low GWP refrigerants and optimized nanofluid formulations for sustainable refrigeration applications.