Analysis of effecting factors on domestic refrigerators’ energy consumption in use

In order to determine the sensitiveness of refrigerators’ energy consumption on various operational factors reflecting real life conditions, four different refrigerators were tested in laboratory using Box–Behnken design with three variables (ambient temperature, thermostat setting position and additional heat load by storing warm food) at three different levels. The investigations show that the energy consumption of refrigerators is highly sensitive to actual operational conditions. Daily energy consumption of one and the same appliance may vary between a few watt-hours and 2000 Wh and even more, dependent on the respective operational factors. Analysis of variance (ANOVA) reveals that ambient temperature is the most influential factor on the energy consumption of a refrigerator. Energy use is also affected, to a minor degree, by internal compartment temperature and additional heat load. Test results are presented and energy consumption data are compared with values shown on the European Energy Label. Results are discussed also with regard to the question as to whether or not the Energy Label and the associated test standard are appropriate to project actual energy consumption in use.