Achieving Substantially Reduced Energy Consumption in European Type Refrigerator

摘要

For several years the Energy Group at Physics Laboratory III has been working on improving energy efficiency of household appliances. Part of the work is analytical, but in recent years also experimental work has been carried out, especially on refrigerators. In Europe it is common to have refrigerators with + 5 deg. C and freezers with -18 deg. C as two separate units. This is appropriate from an energy conservation point of view, and we have therefore investigated a typically sized 200 litres refrigerator with automatic defrosting but no freezer compartment. At present one such prototype at our laboratory shows an electricity consumption of 82 kWh/year, according to European standard test procedures. This is around 45% of the consumption for the best model on todays Danish market with the same features (or 16% of what was typical in 1973). The costeffectiveness of our improvements seems good. The paper describes how our prototype is designed to achieve the savings by 1) lowering transmission loss by moderately increasing insulation thickness and 2) increasing COP by reducing temperature differences between heat exchangers and the surrounding air. The reduced temperature differences are in turn obtained by redesigning the heat exchangers for larger sizes and larger heat capacities. Although a COP value of 2.3 is attained there is still room for improvements towards the value of 14 for a thermodynamically ideal system. (ERA citation 13:036600)