APPLIED METHODS FOR ASSESSING FLAMMABILITY RISKS OF HFO REFRIGERANTS

摘要

Manufacturers worldwide are developing substitutes for refrigerants with high global warmingpotential (GWP) to address climate change concerns. Since 2007, we have used fault tree analysis(FTA) and Computational Fluid Dynamics (CFD) modeling to evaluate the safety of hydrofluoroolefin(HFO) refrigerants in the automotive and stationary sectors, an approach that has proven acceptable toseveral regulatory bodies. In this paper we describe the overall approach we have used, illustrated byseveral case examples involving HFO refrigerants (e.g., HFO-1234yf and HFO-1234ze(E)). Thisincludes a description of open source CFD software to assess and visualize refrigerant dispersion. Wealso discuss the challenges of FTA parameterization when quantitative data are scarce, particularly asregards human factors. Finally, we share our experience using probabilistic tools for evaluating FTAuncertainty and comparative approaches for placing risks in context for the benefit of regulatoryauthorities.