Introduction of an "energy goodness" number for supermarket

A test method for determining the efficiency of supermarket refrigeration systems has been developed. The test method is based on a combination of measurements of air temperatures and energy consumption on an actual system and calculations of the energy consumption for a reference refrigeration system. The reference system is identical to the actual system regarding type, number and size of components but the component efficiencies and cooling demands are assumed to be equal to market average values.The energy efficiency of the system is expressed by a “Goodness Number” defined as the ratio between the calculated energy consumption of the reference system and the measured energy consumption for the actual system. Four different Danish supermarkets have been tested using this method. The results show that supermarkets in Denmark can be expected to have “Goodness numbers” ranging from 0.42 to 0.75 depending on the type and age of the refrigeration system.