Experimental assessment of bio-nanolubricants on the performance characteristics of a developed refrigeration system using R600a

Department of Mechanical and Mechatronics Engineering, Tshwane University of Technology, Pretoria 0183, South Africa.

Abstract

This study involved synthesizing biodegradable nanomaterials to formulate nanofluids for a vapour compression refrigeration system. The importance of the refrigeration system for household appliances cannot be overemphasized due to the preservation of perishable items such as vaccines, food, and beverages and the comfort it delivers in both developed and underdeveloped countries. Its high level of energy consumption has led to the optimization of the system using various techniques, such as increasing the surface area of the heat exchanger, utilizing low global warming potential (GWP) and zero ozone depletion potential (ODP) refrigerants, and applying heat transfer enhancers like nanofluids derived from organic waste to enhance the heat transfer properties of the working fluid (R600a) in order to improve the performance of the system by increasing the coefficient of performance (COP) and reducing energy consumed. Isobutane (R600a) was selected due to its ODP = 0 and GWP < 5. The energy consumption rate by the compressor during experimental evaluation is reduced, with an increased COP and a drop in the evaporator temperature. The results show that the COP of the refrigeration system using a concentration of 0.5 wt% bio-nanofluid performed excellently compared to the control and 0.1 and 1.0 wt%, with an increase of 61.7%, 24.3%, and 13.1%, respectively, while the lowest evaporator temperature (ET) was achieved in 120 minutes.