Thermodynamic analysis of a vapor compression refrigeration system with internal heat exchanger using hybrid nanolubricant

With the development of technology, the energy demand is constantly increasing worldwide. Fossil fuels are predominantly used in energy production. In this respect, energy production is a process with limited fuel resources, costly and also has negative effects on the environment. Cooling and air conditioning systems also have an important share in energy consumption. Increasing the performance of the cooling system will provide serious energy savings. Continuous studies are being carried out to increase the performance of cooling systems. In recent years, studies on the use of nanoparticles have become widespread. It is seen in the studies that the use of nanolubricants increases system performance. The use of mono and hybrid nanolubricants is predominant in the studies. In this study, the performance of the vapor compression refrigeration system using mono and hybrid nanolubricants is analyzed. R1234yf refrigerant was used in the system. The system performances of the base POE and mono and hybrid nanolubricants at 0.5% and 1% concentrations were compared. TiO2 and Boron (B) nanoparticles, which are rarely seen in the literature, were used as nanolubricants. In the experiments, nanolubricants were prepared by mixing them into POE in mass ratio. The performances of POE and nanolubricants at concentrations of 0.5% TiO2, 1% TiO2, 0.5% B, 1% B, 0.5% TiO2-B, 1% TiO2-B were calculated with and without heat exchanger. According to the experimental results, the highest COP increases compared to POE were obtained as 10.46% and 10.65% in 1% TiO2-B hybrid nanolubricants with and without heat exchanger, respectively. The highest decrease in compressor energy consumption was obtained as 8.06% and 7.94% in 1% TiO2-B hybrid nanolubricant with and without heat exchanger, respectively, compared to POE. The highest improvement in exergy efficiency compared to POE was obtained as 28.48% and 23.36% in 1% TiO2-B hybrid nanolubricant with and without heat exchanger, respectively. The improvement in total exergy destruction compared to POE was obtained as 8.72% and 7.92% in 1% TiO2-B hybrid nanolubricant with and without heat exchanger, respectively. In environmental-economic value, 8.06% and 7.94% improvement was calculated in 1% TiO2-B hybrid nanolubricant with and without heat exchanger, respectively, compared to POE. As a result, the hybrid nanolubricant used in the heat exchanger vapor compression refrigeration system showed better performance than the base POE and mono nanolubricants.