Challenges and difficulties in developing nanorefrigerants, nanolubricants, and way forward

The nanorefrigerants and nanolubricants are recently developed nanofluids to enhance the efficiency of the refrigerant systems and lubricating systems. These nanofluids have several advantages such as enhancement in heat transfer processes and tribological properties. The uniform distribution of nanoparticles, to avoid agglomeration and stability, is achieved through sonication but still needs more work to get long-term stability for these nanofluids. This chapter discussed the advantages, challenges, and their appropriate solution during the nanofluids' development. A systematic study is collected about the health-related issues and environmental problems related to these nanofluids to explore the consequences of nanorefrigerants and nanolubricants. Sustainability and durability are also discussed here in detail. The way forward and future challenges and their probable solution are reviewed for these new nanofluids.