Assessment of factors affecting R290 concentrations arising from leaks in room air conditioners.

Currently R290 is used to a small extent in room air conditioners, such as split, portable and window types. Products are limited to relatively small cooling capacities due to refrigerant charge sizes being constrained to around 300 – 400 g, on account of maximum charge formulae within standards IEC 60335-2-40, ISO 5149-1 and EN 378-1. This is especially challenging in warm countries where the cooling load is greater and charge sizes need to be larger. Work is underway to improve maximum charge size determination methods for a given room size. As a contribution to this on going process, further research has been carried out to understand the factors that affect development of flammable concentrations within rooms in event of a leak. Parameters related
to the characteristics of room air conditioners and installations have been investigated experimentally by measuring R290 concentrations from releases and selected findings are described.