Proceedings of the International Conference on Mechanical Engineering and Renewable Energy 2013 (ICMERE2013) 24- 27 December 2013, Chittagong, Bangladesh ICMERE2013-PI- ENERGY & 2ND LAW ANALYSIS OF DOMESTIC AIR-CONDITINOING SYSTEM USING DIFFERENT REFRIGERANTS Santoshi Saha, J. U. Ahamed, Debdatta Das, Farzana Akter, Md. Shamim Hossain Department of Mechanical Engineering. Chittagong University of Engineering & Technology, Chittagong-4349, Bangladesh. E-mail: saha_santoshi2008@yahoo.com Corresponding author: Dr. Jamal Uddin Ahamed. Assistant Professor .Department of Mechanical Engineering. Chittagong University of Engineering & Technology, Chittagong-4349, Bangladesh. E-mail: jamal293@yahoo.com. Mobile: +8801720641636 Abstract- In this research, considering the possibilities of research in various energy sectors and environment existence where Vapor compression refrigeration system (VCRS) are used, an analytical and comparative investigation based on second law of thermodynamics using different refrigerants and REFPROP 7 software in air- conditioning system is being evaluated. Thermodynamics analysis such as co-efficient of performance (COP), refrigerant effect and compressor work, exergy efficiency and exergy losses has been investigated at different operating condition. In this study, different refrigerants such as R22, R290, R410A, R22/R290 (4:1)(M1) and R22/R290(50:50)(M2) has been considered by keeping in mind GWP and ODP. It has been found that using blend of hydrocarbon R290 and HFC R22 in about 20% and 80% by mass respectively i.e. R22/R290 (4:1)(M1) as an alternative refrigerant for the system provides best result than the other refrigerants. From this study, it has been observed that the mixture M1 shows the better co-efficient of performance (COP) and exergy efficiency than other refrigerants considered. It also has been found that the mixture M1 has lower compressor work and exergy destruction than the different refrigerants considered. So, mixture of hydrocarbons shows the best performance based on the energy and exergy analysis. Keywords: Alternative refrigerants; Thermodynamic performance; REFPROP 7; Exergy loss; Exergy efficiency. 1. INTRODUCTION Vapor compression refrigeration system (VCRS) is the prime sector in energy area where most of the system continues to run on halogenated refrigerants due to its excellent thermodynamic and thermo- physical properties. But, halogenated refrigerants have adverse impacts such as ozone depletion potential and global warming potential. In the earlier date, the performance of this system is estimated based on only the energy performance of the system. Energy analysis has been dealt with 1st Law of Thermodynamics. But, nowadays with the increase of use of energy and creation of entropy it has become relevant to deal with the quality aspect of energy which is known as exergy analysis. Exergy is defined as the available energy which can be converted into a work. Since the world energy crisis in the early 1970s, scientists and researchers have focused to recover the energy usage, exploit renewable energy resources and diminish the impact of energy use on the environment [1].Chlorofluorocarbons (CFCs) and Hydro chlorofluorocarbons (HCFCs) were commonly used as refrigerants in the domestic refrigerator for the last few decades. In recent decades, the concept of global warming, greenhouse effect and sustainability has entered into the engineering world. HFC refrigerants are used as a refrigerant for their high thermodynamic performance. However, HFC showed high GWP on the environment. Due to rapid economic growth during the last few decades, it is accompanied with more offices, buildings in the world, which is causing the more energy consuming, more energy loss and environmental problems. In Bangladesh, more than 14% energy is consumed by air-conditioning system including refrigeration and cooling system which is really high as compared to different sectors. The last decade has seen radical changes in the selection and use of refrigerants, mainly in response to the environmental issues of ‘holes in the ozone layer’ and ‘global warming or greenhouse effect’. High Global Warming Potential (GWP) and Ozone Depletion Potential (ODP) and greenhouse effect from these refrigerants have led to the profound study for the alternative refrigerants. As per Montreal protocol 1987, developing countries are required to phase out all CFC by 2010 and all HCFCs by 2040.GWP is relative value, used to compare the impact of an emitted gas on the climate and its contribution to climate change. Comparable study on R22, R1270 and R290 has been found that R290 is the best alternative to R22. Their research was based on the small capacity system. But this hydrocarbon has flammable property. So, it is necessary to think about non-flammable refrigerant, having zero GWP,