The impacts of synthesized Ag doped ZnO nano-materials on the energy efficiency of the refrigeration system

Nanofluids are used to increase thermal performance in various applications of heat transfer. In the present study, to increase the performance of the cooling system, nanolubricant prepared with zinc oxide (ZnO) and silver (Ag) doped ZnO nanoparticles were used. ZnO and Ag/ZnO nanoparticles were synthesized via precipitation and co-precipitation methods, respectively. The effects of Ag particles added to ZnO nanoparticles at the rate of 5% on thermal performance were investigated. XRD and SEM examinations of the synthesized nanoparticles were made in detail and their suitability was determined. Nanolubricants were prepared by mixing 0.5% and 1.0% (wt./wt.) ZnO or Ag/ZnO and 0.5% (wt./wt.) Tween 80 (T80). The coefficient of performance (COP) values maximum increased by 18.20% and 23.68%, respectively, in the use of mineral oil with added 1.0% ZnO and 1.0% Ag/ZnO nanoparticles in the nanolubricants. In the cooling system, the compressor work decreased by 18.71% using the nanolubricant prepared with Ag-doped ZnO hybrid nanoparticles at a 1.0% mass fraction.