Performance variation of an R22 window air conditioner retrofitted with a HFC/HC refrigerant mixture under different ambient conditions over a range of charge quantities

Abstract

AbstractR22 has been generally accepted as the most suitable refrigerant for air conditioners, due to its favorable thermodynamic properties. However, R22 is a controlled substance under the Montreal protocol. M20 is a HFC/HC refrigerant mixture that can be used as a substitute for R22. This paper presents experimental investigation on the performance comparison of a window air conditioner operated with the M20 tested under different refrigerant charge levels and outdoor conditions against that with R22. Experiments were conducted in accordance with BIS procedure in a psychrometric test facility. Refrigerant charge in the air conditioner was systematically varied from 900 to 1600 g in steps of 50 g for R22 and 697 to 1279 g in steps of 39 g [equivalent to 50 g of R22] for the M20. At each charge levels, the outdoor room conditions were changed in accordance with BIS standards. It is observed that R22 is more sensitive to deviations in charge levels as compared to the M20. A decrease in charge level of about 7% reduced the system refrigerating capacity by 11.3% with R22 while with the M20 refrigerant mixture it reduces by 6.9% only. Similarly an overcharge by 7% reduces the refrigerating capacity of the system by 13.8% with R22 while with M20 it reduces by 6.5% only. Thus M20 is less sensitive to charge deviations. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20339