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This content will become publicly available on May 6, 2019

Title: Evaluation of flammable volume in the case of a catastrophic leak of R-32 from a rooftop unit

With the effort to use alternative refrigerants with lower global warming potential (GWP), the majority of these alternative refrigerants are classified as slightly flammable. Here in this paper we report on the numerical evaluation of a catastrophic leak scenario of R-32 refrigerant from a 3-ton roof top air conditioning unit (RTU) which serves a 12.2 × 9.14 × 2.4 m room. A full rupture of a 6.35 mm (¼ inch) pipe downstream of the evaporator coil is simulated. Two separate cases with refrigerant releases of 1.81 kg and 3.62 kg charge have been studied. The two charges are released in 10.2 and 20.4 s, respectively, just after the end of a unit cooling cycle. The flammable volume inside the room existed only for about 40 s with a maximum flammable volume inside the room of 1.12% of the total room volume for the 3.62 kg charge case.
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  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
International Journal of Refrigeration
Additional Journal Information:
Journal Volume: 91; Journal Issue: C; Journal ID: ISSN 0140-7007
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (EE-5B)
Country of Publication:
United States
42 ENGINEERING; 29 ENERGY PLANNING, POLICY, AND ECONOMY; 54 ENVIRONMENTAL SCIENCES; Catastrophic leak; Rooftop unit; Flammable Volume; R-32; Fuite catastrophique; Unité de toiture; Volume inflammable
OSTI Identifier: