Safety features of HC refrigerants in car air conditioning

Hydrocarbon (HC) refrigerants are environmentaly safe, readily available, non toxic, and have good thermodynamic and transfer properties. However, they are also flammable. The subject of this paper is the effect of leakage of refrigerant into the passenger compartment of a vehicle from an assumed fracture in the refrigerant circuit. If the resultant mixture in the passenger compartment is close to stoichiometric, it can be ignited and create sufficient overpressure to damage structures. The result of the research described in this paper is a set of requirements necessary to avoid this scenario.