The effects of Multiwalled Carbon Nanotube to the performance of a refrigeration system

Abstract

By incorporating nanofluid technology and nanolubricants into compressors, the performance can be enhanced while also lowering worldwide fuel consumption and aiming at developing cleaner, more efficient energy sources and uses. The globe is being confronted with energy security issues and heating, cooling and HVAC systems highly contribute to it. Hence, it is critical to save energy and improve the efficiency of the refrigeration cycle. This study presents experimental and theoretical findings in order to investigate the effect of Polyester (POE)-oil based multiwalled Carbon Nanotube (MWCNT) nanolubricant on the Coefficient of Performance (COP) of a refrigeration system. The objectives of this study is to analyze the stability of MWCNT nanofluids, to obtain the COP of a refrigeration cycle run with pure POE oil and MWCNT nanofluids with different concentrations respectively. The experiment was conducted by preparing 0.55, 0.65 and 0.70 g/l MWCNT nanofluid by using the two step method. The most effective concentration used in the refrigeration system was referred to the one that resulted in the highest COP. It was determined from the experiment that 0.55 g/l MWCNT nanofluid resulted in a higher COP of 5.766 as compared to the other two concentrations. Besides, it showed an improvement of 34.6% in COP as compared to the COP of using pure POE oil in the refrigeration system, which was found to be 4.285. The 0.65 g/l and 0.70 g/l concentration of MWCNT resulted in a COP of 5.618 and 5.617, respectively. The compressor work was also analyzed and was found to be reduced noticeably after adding MWCNT nanoparticles. Hence it can be concluded that the increment of MWCNT concentration in nanofluids increases the COP of the refrigeration system but only up to a certain limit of concentration.