IIR document

Refrigerant egression to connected spaces in relation to hydrocarbon charge limits.

Number: 0009



Safety standards specify allowable refrigerant charge limits for refrigeration systems based on the size of the room that the system could leak into. However, in practice, rooms may be connected to other spaces by means of doorways or other permanent openings. Such openings may potentially provide a larger effective room area across which a leak could disperse, implying allowable charge limits could also be based on this larger total area. There are formulae within current safety standards that relate “natural ventilation” opening size to allowable refrigerant charge, but in many cases their lineage and underlying assumptions are unclear. The present work addresses this topic of “refrigerant egression” to connected spaces primarily using computational fluid dynamics, supported by measurements, to examine behaviour under a variety of arrangements. Following analysis of the results, an alternative formula is proposed for egressed mass of leaked refrigerant or conversely the minimum egression opening areas as required to permit an incremental charge amount of hydrocarbon refrigerant.

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Pages: 12 p.


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  • Original title: Refrigerant egression to connected spaces in relation to hydrocarbon charge limits.
  • Record ID : 30029654
  • Languages: English
  • Subject: Technology
  • Source: 15th IIR-Gustav Lorentzen Conference on Natural Refrigerants (GL2022). Proceedings. Trondheim, Norway, June 13-15th 2022.
  • Publication date: 2022/06/13
  • DOI: http://dx.doi.org/10.18462/iir.gl2022.0009
  • Document available for consultation in the library of the IIR headquarters only.


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