Risk Assessment of Catastrophic Leak Of R-452b From Package Unit into A Residential Space

With the effort to find alternative refrigerants with lower global warming potential (GWP), challenges have arisen due to the flammability risk for many of the alternatives. One of the new alternatives is R452B, which is recommended as a replacement for R410A. R452B is classified as a mildly flammable refrigerant (A2L) by ASHRAE 34. This paper summarizes a CFD simulation study of a leak incident of R452B from a 3-ton packaged unit which serves a 167 m2 residence. The R452B leak is assumed to be downstream of the evaporator coil. The simulated residence has four rooms and a hall way. The packaged unit distributes the conditioned air through a supply duct system delivering the air through registers. The dispersion of R452B is characterized for two scenarios: one with underfloor supply air ducts and another with ceiling supply air ducts. The mass flow rate of R452B exiting the duct outlets is quantified and the refrigerant volume fraction is monitored inside the residential space.