Study on risk assessment of air conditioner using R290.

Nowadays, further phase-down of HFC is expected to encourage the use of lower GWP refrigerants, but the majority of the refrigerants with low GWP values tend to have high flammability and there is a danger of explosion that may cause fire. In general, the occurrence of an ignition event of a flammable refrigerant has much to do with the development of flammable cloud and the existence of ignition sources such as static electricity and electric sparks. For risk assessment, therefore, it is necessary to determine the volume and duration of flammable cloud following refrigerant leakage. In this paper, CFD simulations was undertaken to evaluate the volume and duration of flammable cloud generated by leaked refrigerant from an outdoor unit under several sets of given conditions. The CFD results indicated flammable regions stagnated so long that ignition risks may be intolerable under certain circumstances.