Minimizing emissions in 3 Australian supermarkets by using R-290

AIRAH (Australian Institute for Refrigeration Air-conditioning and Heating) has published a case study on 3 Aldi supermarkets in Australia that are minimizing greenhouse gas emissions by using R-290 (propane) chest freezers in their retail frozen food departments. Located in Victoria, New South Wales and Queensland, the supermarkets feature between 22 to 24 chest freezers units, that each houses a self-contained R-290 hermetic compressor with variable speed drive. The case study compares the R-290 chest freezers solution to a R-404A two-stage system as well as a CO2/R-134a cascade. The energy efficiency of the R-290 system has been found to be equivalent to that of a two-stage R-404a system. The R-290 system uses slightly more energy than CO2/R-134a cascade system, with the latter therefore encompassing slightly lower indirect emissions than R-290 that are however offset by higher direct emissions due to refrigerant leakage. When refrigerant leakage and refrigerant recovery losses (refrigerant that is not recovered at the end of the equipment life) are taken into account, R-290 is assessed to save approximately 17 tonnes of greenhouse gas emissions per year compared to a R-404A two-stage system when a 5% annual leakage rate is assumed for the latter. EcoLibrium, February 2011