Energy conservation in vapour compression refrigeration system using vapour injection technique

Abstract

In modern days, the vapour compression refrigeration system is followed in almost all air-conditioning applications. Due to the high ambient temperature during extreme summer conditions, the commercial vapour compression refrigeration system made with cost competitiveness are not in a position to meet the required indoor conditions (27°C Dry Bulb Temperature and 19°C Wet Bulb Temperature) within a stipulated time. Hence a study on the performance of vapour compression refrigeration system is needed without compromising the required indoor conditions. This paper concentrates on the use of an innovative technique called vapour injection in the rotary compressor. The rotary compressor based air-conditioning system is considered in this study as it is used widely across the world, particularly in domestic applications. This vapour injection technique meets the required indoor conditions with significantly increased cooling capacity and coefficient of performance (COP) by lowering the condensing temperature and increasing sub-cooling. A 1.5 TR vapour compression refrigeration system equipped with a rotary compressor is taken for study along with a refrigerant R22. Around 90% of heating, ventilation and air-conditioning systems in India use R22 refrigerant which is permitted to be used up to year 2030. A conventional vapour compression refrigeration system is redesigned towards injecting additional low temperature refrigerant vapour back into the compressor just before the suction port. At standard test conditions, 11.87% to 12% of higher cooling capacity is achieved with 1% to 2.5% of less power consumption which resulted in 13.3% to 15% of higher COP.