Analysis of Eco friendly Refrigerants Usage in Air-Conditioner

Abstract

Problem statement: There are two types of global warming contributions through refrigeration and air conditioning systems. The first one is the Direct Global Warming Potential (DGWP) due to the emission of refrigerants and their interaction with heat radiation. The second one is the Indirect Global Warming Potential (IDGWP) due to the emission of Carbon Dioxide (CO₂) by consuming the energy that is generated through the combustion of fossil fuels. Most of refrigerants used in vapor Compression system were Chlorofluorocarbon (CFCs) and Hydro Chlorofluorocarbon (HCFCs) which contains chlorine and if any leakage in the system, these gases will go up and reach stratosphere. The chlorine atoms in the gases will act as a catalyst to destroy ozone layer and cause ozone depletion which causes health hazards, global warming, melting of polar ice caps and drought. Hence, it is necessary to minimize the Global warming and Ozone depletion. The refrigerant R22 widely used in the air-conditioners is a major Contributor of Chlorofluorocarbons (CFCs) which cause irreparable loss to the ozone layer and has to be replaced. Approach: To conserve the energy and minimize the global warming, the systems should be designed as more energy efficient and also to minimize Ozone depletion, the eco friendly refrigerants are to be selected and tested as alternative refrigerants to R22. Hence, a window air conditioner of 3.5 kW capacity fitted with Electronic Expansion Valve (EEV)) instead of capillary tube as an expansion device, was tested for its performance with the selected eco friendly refrigerants R407C and R290 as an alternative to R22 under fixed indoor and outdoor chamber temperatures in the experimental set up and varying the EEV opening. Results: It has been observed from the experimental studies that when the smaller capacity R22 window air conditioner with EEV is retrofitted with R407C and R290, compared to the performance given by R22, the Coefficient Of Performance (COP) given by R407C and R290 is improved in the range of 4.8-7.1 and 8.0-12.3% respectively and the Energy Efficiency Ratio (EER) is increased by 4.2-6.9% for R407C and 6.4-10.8% for R290. Conclusion: The performance of Electronic Expansion Valve (EEV) with eco friendly refrigerant R290 in the given air conditioner shows a positive effect in terms of COP and energy efficiency and enables the industry to favorably displace the R22 and other types of expansion devices.