Performance of a domestic refrigerator in varying ambient temperatures, concentrations of TiO2 nanolubricants and R600a refrigerant charges

This study investigates the effect of varying test conditions including ambient temperature (19, 22, and 25 degrees C), mass charges of R600a refrigerant (40, 50, 60, and 70 g), and concentrations of TiO2 nanolubricant (0, 0.2 and 0.4 g/L) on the performance of a slightly modified 100g R134a domestic refrigeration system. The investigated parameters include evaporator air temperature, energy consumption, coefficient of performance, and second law efficiency of the system. The results showed that the performance of the refrigeration system at 0.2 and 0.4 g/L concentrations of TiO2 nanolubricant, improved at optimum ambient temperature and R600a mass charge conditions. At optimum conditions, the evaporator air temperature and energy consumption reduced within the range 5.26 to 26.32 %, and 0.13 to 14.09 % respectively, while the coefficient of performance and second law efficiency increased within the range 0.05 to 16.32 %, and 2.8 to 16 %, respectively. However, at other conditions (non-optimum), the energy consumption and evaporator air temperature were higher and within the range 0.28 to 8.26 %, and 5 to 40 % respectively, while the coefficient of performance and second law efficiency reduced within the range 2.99 to 10.94 %, and 0.55 to 13.43 % respectively. In conclusion, we observed variations in the performance of the refrigerator with varying test conditions.

Automated summary

This study found that the performance of a domestic refrigeration system improved with TiO2 nanolubricant at optimal ambient temperature and mass charge conditions, while deteriorated at non-optimal conditions. Energy consumption and evaporator air temperature increased, while coefficient of performance and second law efficiency decreased with non-optimal conditions.