21 December 2010

Using heat pumps for energy recovery in supermarket refrigeration systems

Energy consumption of each conventional supermarket represents up to 50 % of the primary energy consumption for food cooling and freezing, while rejecting enormous amounts of excess heat outdoors. Basic heat recovery systems allow recovery
by desuperheating up to 40 % of the compressors’ discharge energy, but this amount of heat isn’t sufficient for integral supermarket space and hot water heating in northern climates. Heat pumps and direct heat recovery heat exchangers may overcome this problem, and thus help improve the overall energy efficiency of supermarket refrigeration systems. This article compares the basic heat recovery method in direct-expansion supermarket refrigeration systems with other concepts using heat pumps and direct heat recovery coils. Measured parameters, such as refrigerant and warm secondary fluid temperatures, show potentials for using low- and high-temperature heat pumps in supermarkets located in cold and temperate climates.