Nanorefrigerant are used extensively in refrigeration applications due to their improved heat transfer properties. It requires a working fluid with high heat transfer coefficients to achieve maximum thermal performance. In the present work, a mixture of R600a-CuO nanorefrigerant is used as a working fluid for a direct cooled refrigerator. The heat transfer rate is increased by 83 % using R600a-CuO instead of a pure refrigerant. The objectiev is to test the performance as per Indian Standards of a direct cooled refrigeration system using nanorefrigerant R600a-CuO. The system is tested with pure R600a and CuO nanoparticles; at two concentrations (0.04 g and 0.08 g). Nanoparticles improve results from thermal performance concerns than a pure refrigerant, and the saving is higher at higher ambient temperatures. The energy consumption is reduced by 4 % and 8.2 %, with lower concentrations at 27 °C and 38 °C, respectively. The pulldown time is also significantly reduced. The highest pull-down reduction reductions and energy consumptions are 13.18 % and 12.89 % with 0.08 g nanoparticles and at 38 °C ambient temperature. The system functions efficiently with the modified medium.