An experimental and numerical study of refrigerant leaks in refrigerated transport containers

While the use of flammable refrigerants is an active area of research within the heating, ventilation, air conditioning and refrigeration (HVACR) industry, limited work has been documented on their use for refrigerated transport applications. Hydrofluoro-olefin (HFO) refrigerants are currently under investigation and are expected to see expanded use when safety, efficiency, and reliability can be delivered. Recent industry work has identified the importance of understanding the fluid dynamics of refrigerant leak events in order to predict the flammability risks posed by flammable refrigerants. This paper describes the first steps towards a comprehensive computational fluid dynamics (CFD) based simulation framework to assess the risks of flammable refrigerant leaks in a marine refrigerated container. The paper details experimental testing of leakages under a range of scenarios and validation of a CFD model setup for leaks that occur when evaporator fans in the refrigeration unit are operating. Results are presented for spatial and temporal distributions of concentration within a sealed and unventilated container for experiments and simulations. The next steps of this work will replicate these steps of the framework for the more challenging scenarios in which fans are powered off.