Experimental investigation of the effect of nanoparticle and surfactant addition to refrigerator compressor oils on energy efficiency and cooling performance

It is well known that the size of nano particle additives used in cooling systems to increase cooling performance and reduce energy consumption should be as small as possible, otherwise they will cause precipitation and blockage in the system. In this study, long-term experiments were conducted on the same type and model of household refrigerators in a laboratory environment. The same and different types of nano particles (0.05%, 0.2%, 0.5%, 3 nm, 13 nm and 18 nm in size) and surfactant (0.5%) were added to the oil of the refrigerator compressors. The energy performance of the refrigerators was compared with an equivalent refrigerator without any change in the compressor oil and the watt, wh, kWh/24 energy values of 5 refrigerators were monitored simultaneously and frigo, freezer, condenser, compressor, room temperature values were monitored under exactly the same environmental conditions with 15-day tests. Results are averaged over all days. All cabinets were tested under exactly the same conditions throughout the process. First, a short-term experiment of 2.5 hours was conducted and energy efficiency of up to 37.5% was achieved in all refrigerators. First, a short-term experiment of 2.5 hours was conducted and energy efficiency of up to 37.5% was achieved in all cabinets. Then, long-term experiments were started and when the results were evaluated, 5.55% energy efficiency was achieved in the first 30 days of the trial with Al2O3 0.5% + Tx 100 0.5 ml ratio, which was repeated 4 times. A negative trend was observed in the tests after 30 days. In particular, in refrigerators with some nano particles added, high energy efficiency was observed at the beginning, but as the process progressed, it was found that the energy efficiency decreased. These reductions are predicted to be caused by the precipitation of nano particles and the blockage of capillaries in the system. It is believed that by providing the necessary continuity and stabilization, and by studying and resolving the negative effects of nano particles on the cooling closed cycle, significant energy savings can be achieved. This experiment showed that nano particle-added compressor oils can increase the energy efficiency of the refrigerator for one month, but it is not sustainable in the current situation because the precipitation problem cannot be avoided.