Studies on R22 room air conditioner with electronic expansion valve and retrofitted with R407C and R290

Abstract

Worldwide many research activities are carried out to mitigate the ill effects of Gobal Warming, Ozone layer depletion and climate changes. For the past 20 years efforts are made to phase out the production and consumption of Hydro Chloro-Fluorocarbon (HCFCs) and Chloro-Fluorocarbon (CFCs), as these chemicals are responsible for depletion of stratospheric ozone layer and used in refrigeration and air-conditioning industry. Current literature review has indicated that to satisfy the objectives of International protocols, many research works are in finding out a suitable alternative refrigerant with low Global Warming Potential (GWP) compared with R22, minimizing the mass of refrigerant charge used in the system, enhance and ensure energy efficient system operation by adding intelligence to components and enhance the energy efficiency of the system. In this direction, retrofitting of existing R22 room airconditioning system with eco friendly refrigerants R407C and R290 are attempted in the present research work. As the studies are rare for lower capacity air conditioning system with Electronic Expansion Valve (EEV) as an expansion device, one TR (3.45 kW) capacity room airconditioning system is taken for study. Most of 3.45 kW capacity air conditioning systems are made with Capillary Tube (CT) as an expansion device. Apart from CT, the system with Thermostatic Expansion Valve (TEV) and EEV are also tested and compared for their performance. An experimental test facility has been fabricated as per Bureau of Indian Standards (BIS) IS -1391(1992) part I. The test facility consists of room air conditioner of 3.45 kW capacities, indoor and outdoor environmental chambers with necessary instrumentation, provision to measure the temperature and pressure at various locations and refrigerant mass flow rate are made.