Enhancement of vapor compression cycle performance using nanofluids: Experimental results

Recently, Egypt is facing an energy problem due to the increase in consumption and population. There are two ways to face this issue; first, the world should be more interested in renewable energy resources and the second is the efficient use of energy. Refrigeration and air conditioning systems have a high rate of electrical power consumption. For that, the objective of the present work is to enhance the performance of the vapor compression cycle as well as to reduce the energy consumption resultantly. To achieve these goals, the performance of a vapor compression cycle with nanomaterials additives to the primary loop of refrigeration (refrigerant loop) is investigated experimentally. Mineral oil and polyol ester oil with Al 2 O 3 nanomaterials additives are used to enhance the performance in the vapor compression cycle with R-143a refrigerant. The stability of nanofluids was first tested by using sedimentation test. The results showed that the optimum concentration for nanolubricant is 0.1% mass percentage. Results revealed that the refrigerant heat transfer coefficient increased by 22% maximum when nanofluids were used. Moreover, exergy efficiency increases by 20% when mineral oil and Al 2 O 3 nanoparticles were used. The experimental results indicate that R-134a and mineral oil with Al 2 O 3 nanoparticles enhance the vapor compression cycle performance by 22.5% theoretically and 10% actually with 10% less energy consumption. These results were obtained with 0.1% mass fraction of nanolubricant oil. Moreover, experimental results indicate that the polyester oil with Al 2 O 3 nanoparticles mixture has better performance than mineral oil with Al 2 O 3 nanoparticles mixture by 7.5% in theoretical COP and 19.5% in actual COP.