Performance of TiO

This study examines the performance of TiO2 nanolubricant at concentrations of 0, 0.2, and 0.4 g/L in a slightly modified refrigeration system, tested with door openings of 30, 60, 120, 180, 240, and 300 seconds. The system was charged with 30 g of either LPG or R600a refrigerant, combined with the specified TiO2 concentrations. Monitoring involved a digital pressure gauge, K-type thermocouples, and a wattmeter to assess energy behaviour under closed and open-door conditions. Key performance metrics included closed-door pull-down time, open-door air infiltration heat rate and load, power consumption, compressor power, and recovery rate. All tests complied with ISO 8187, achieving a minimum evaporator air temperature of -3°C within one hour of continuous operation. For both R600a and LPG refrigerants, air infiltration heat rate and load decreased from 0.02162 m3/s and 2.4365 kW at 30 seconds to 0.02085 m3/s and 0.602 kW for door openings of 60 to 300 seconds. Conversely, recovery rate, energy consumption, and compressor power increased with longer door openings. Adding TiO2 nanolubricant reduced recovery rate by 1.08%65.8% for R600a and 2.12% - 85% for LPG, compressor power by 4.14%43.01% for R600a and 5.92% -30.92% for LPG, and energy consumption by 13.33% - 66.67% for R600a and 5.88% - 80% for LPG. Overall, TiO2 nanolubricants substantially mitigated the impact of air infiltration into the evaporator cabinet.