R-407H as drop-in of R-404A. Experimental analysis in a low temperature direct expansion commercial refrigeration system

This work analyses experimentally the possibility of using the reduced GWP refrigerant R-407H (HFC family, GWP = 1378) as drop-in substitute of R-404A (HFC family, GWP = 3945) in low temperature centralized direct expansion refrigeration system. The experimental plant and the test methodology are described. It covered top up or partial drop-in and energy consumption tests at −20 °C of product temperature and 25, 35 and 45 °C of condensing temperature using a small-scale supermarket under laboratory conditions. It has been measured that the use of R-407H instead of R-404A is favourable from the point of view of energy efficiency. Reductions in the energy consumption of up to 7.7% (compressor) and 4.0% (whole system) have been measured. However, there is an increment in the compressor's discharge temperature of up to 13.8 K. In addition, the operation of the system with both refrigerants was correct.