The application of nano refrigerants in refrigeration system is considered to be a potential way to improve the energy efficiency and to make the use of environment-friendly refrigerants. In this paper we report a method that uses natural gas to enhance the energy efficiency of refrigeration retorting method employing CuO - R600a as alternate refrigerants. Thus reliability and performance of nano refrigerant in the working fluid have been investigated experimentally. A new nano refrigerant is employed in the domestic refrigerator. The performances of the nano refrigerant, such as the cooling capacity, energy efficiency ratio were determined. The results indicate that the mixture of R600a with nano particles (CuO) works normally in the domestic refrigerator. The cooling capacity of the domestic refrigerator is increased by 10 - 20% by using nano - refrigerant. The performance calculation of suction pressure, discharge pressure at no-load, part-load, fully-loaded condition, and running time, COP. © 2015 Elsevier B.V., All rights reserved.