This study evaluated the flammability hazard of R-290 propane in refrigeration appliances used in commercial retail and kitchen settings. The specific objectives were to:
- assess the flammability risk versus charge size; and
- develop recommendations on how to prevent or mitigate the risks when using R-290 in commercial retail and kitchen applications.
This type of study is needed to establish a technical basis for any changes to the current charge limits and to help determine whether A3 refrigerants can replace non-flammable refrigerants in a broader range of refrigeration applications that require larger charges than currently allowed by standards.
When a flammable refrigerant is released from a refrigeration cycle, there are several factors that affect the potential severity of the event including properties of the refrigerant, characteristics of the leak, properties of the equipment, and aspects of the environment. Two very important factors that must be considered are:
- the increased release rates associated with leaks in the liquid lines; and
- whether releases in confined areas, like the condensing unit housing, impinge on adjacent surfaces and lose their momentum.
The present study considered these two main factors, along with many others, and used computational fluid dynamics (CFD) to examine in detail how each factor influenced the outcome of a leak.
