The use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) has been widely restricted. They have been replaced with hydrofluorocarbons (HFCs) in order to protect the ozone layer. However, the leakage of refrigerant into the air from active or end-of-life air conditioners is a serious environmental issue owing to the high global warming potential (GWP) of HFCs. Therefore, replacing HFCs with low-GWP refrigerants has been recognized as a reasonable solution to the problem. In Japan, low-GWP refrigerants such as R1234yf, R1234ze, and R32 have been considered as alternatives to conventional HFC refrigerants. However, these low-GWP refrigerants are often flammable.

Numerical analysis is an effective tool in order to understand the refrigerant diffusion phenomena of low-GWP refrigerants because it is very difficult to measure the diffusion of a refrigerant in a large space. In this study, diffusion phenomena were numerically analyzed when a refrigerant leaked slowly from a room air conditioner (RAC) and package air conditioner (PAC) and rapidly from a chiller into a large space. Based on the calculation results, the refrigerant concentration distributions, the volumes and positions of the flammable regions, and their changes in time were examined.

論題

Simulation of leakage of mildly flammable refrigerants

著者

Hiroaki OKAMOTO, Tatsuhito HATTORI, Chaobin DANG, and Eiji HIHARA

掲載誌

Proceedings of International Refrigeration and Air Conditioning Conference at Purdue, No.2459, July 14-17, 2014