Potential replacements for current hydrofluorocarbon (HFC) refrigerants include pure and blended hydrocarbon refrigerants since they have a lower global warming potential (GWP) and comparable working fluid properties.
The current barrier to broader application of these refrigerants is their classification as flammable A3 substances according to ASHRAE 34. As a result, their use is accompanied by additional design constraints to minimize safety hazards.
A current design constraint for A3 refrigerants is a 150 g charge size limit in portable unit systems.
The objective of this project was to understand the severity of ignition events involving R-290 (propane) at charges sizes above the current limit of 150 g to evaluate the viability of class A3 refrigerants as replacements for HFCs in more HVAC&R applications.