Reciprocating Compressor Performance with Nanorefrigerant in a Vapour Compression System

Abstract

ABSTRACT In the present era, refrigeration systems play a vital role to fulfill the human comfort and industrial needs. In the refrigeration systems main energy consuming devices are compressors. The various researches are being carried out in order to reduce energy consumption and improve the performance of these compressors. In the presented work, an attempt has been made to improve the performance of such system. In this study, an experimental investigation into the performance of a reciprocating compressor using pure refrigerant (R134a) and nanorefrigerant (R134a+Al2O3) in a vapor compression refrigeration system has been presented. A standard experimental setup was built up and made to function under varying evaporating temperature conditions. The performance of the refrigeration system depends upon the various factors such as; individual component’s performance, nature and properties of the refrigerant being used and environmental conditions. The experiments have been conducted to investigate the effect of nanoparticles on the COP of the refrigeration system and various efficiencies of reciprocating compressor. The nanoparticles along with the refrigerant are injected into the refrigeration system for the investigations. Aluminium Oxide (Al2O3) nanoparticles of 20 nm diameter are used with two different weight fractions (0.4 and 0.8%) in base refrigerant R134a. Experiments have been conducted with three refrigerant volume flow rates (6, 8 and 11 LPH) and four evaporator heat fluxes (at 20 ºC, 25 ºC, 30 ºC and 35 ºC). The coefficient of performance (COP) of vapour compression refrigeration system is found to be improved for both weight fractions. At a 0.8 % weight fraction COP is found to be maximum. The results show that while working at high volume flow rates and lower evaporator heat fluxes COP decreases. The adiabatic efficiency of reciprocating compressor is improved by using of nanorefrigerant and the results also show that the adiabatic efficiency of reciprocating compressor is improved by working at higher volume flow rates, higher evaporator heat fluxes and with higher weight fractions of nanoparticles. The electromechanical efficiency of reciprocating compressor is found to be improved for both weight fractions of nanorefrigerant and the results also show that by working at high volume flow rates and higher evaporator heat fluxes reciprocating compressor gives higher values of the electromechanical efficiency. It has been also found that the overall efficiency of reciprocating compressor is improved by using of nanorefrigerant and the results also show that the overall efficiency of reciprocating compressor is improved by working at higher volume flow rates, higher evaporator heat fluxes and higher weight fractions of nanoparticles. Thus, using aluminium oxide nanoparticles along with refrigerant in refrigeration system is feasible and within the investigated limits it gives a significant improvement in performance of the reciprocating compressor and refrigeration system.