Evolving an optimal composition of HFC407C/HC290/HC600a mixture as an alternative to HCFC22 in window air conditioners

• Published in: International journal of thermal sciences Vol. 46; no. 3; pp. 276 - 283
• Main Authors: Jabaraj, D.B., Narendran, A., Lal, D. Mohan, Renganarayanan, S.
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01-03-2007; Elsevier
• Subjects: Air conditioning. Ventilation; Applied sciences; COP improvement for window air conditioner; Energy; Energy. Thermal use of fuels; Exact sciences and technology; HCFC22 Phase-out; Heating, air conditioning and ventilation; HFC407C with mineral oil; HFC407C/HC blend mixture; Room calorimeter; COP improvement for window air conditioner; Room calorimeter; HFC407C with mineral oil; HCFC22 Phase-out; HFC407C/HC blend mixture; Air conditioning; Energy consumption; Air pollution control; Uncertainty; Mineral oil; Experimental study; Optimization; Refrigeration
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2006.05.004

Countries that have ratified Montreal Protocol have to phase out HCFC22 in the near future due to its ozone depleting potential (ODP) and hence new eco-friendly refrigerants are being evolved as substitutes. At Present HFC407C is one of the promising drop-in substitutes for HCFC22. But it is immiscible with mineral oil and hence polyol ester (POE) oil is recommended. Since POE oil is highly hygroscopic in nature it is not user friendly. However such oil immiscibility issue of HFC134a has been overcome [M. Janssen, F. Engels, The use of HFC134a with mineral oil in hermetic cooling equipment, Report 95403, No. 07, presented in the 19th International Congress of Refrigeration, The Hague, 1995] by the addition of HC blend to it, which also resulted in performance improvements. In the present work an attempt has been made to study the possibility of using HFC407C/HC290/HC600a refrigerant mixture as a substitute for HCFC22 in a window air conditioner and to evolve an optimal composition for the mixture. Experiments were carried out in a room calorimeter setup fitted with 1050 W capacity window air-conditioner. Condenser inlet air temperatures were held constant at 30, 35, 40 and 45 °C, while evaporator inlet air temperatures were varied over a range viz. 21, 23, 25, 27 and 29 °C during the experimentation. The HC percentage was also varied from 10 to 25% in steps of 5%. The new refrigerant mixtures demand longer condenser length to decrease the high discharge pressure matching with HCFC22 systems and hence the length has been increased while testing the mixtures. This also resulted in better heat transfer in condenser. The performance analysis revealed that the new refrigerant mixture performed better than that of HCFC22. It has in fact been found that the new mixture can improve the actual COP by 8 to 11% and hence it can reduce the energy consumption by 5 to 10.5%. The overall performance has proved that the new refrigerant mixture could be an excellent substitute for HCFC22.