option to improve the overall energy efficiency in supermarkets. The amount of recoverable heat depends on
the required temperature level. In transcritical operation the major share of heat can be recovered on a
temperature level suitable for space heating. However, transcritical operation requires higher compressor
power and results in a lower COP of the refrigeration system. Thus, the saved costs from conventional
heating have to be compared with additional costs for electricity-consumption of the refrigeration system.
This paper analyses the overall energy costs of heat recovery in CO2 refrigeration for supermarkets as a
function of heating requirements and the energy prices for the refrigeration system and space heating.