Experimental investigation on the effects of voltage on a domestic refrigerator

Abstract

This paper gives an experimental analysis of the effects of voltage reduction on a domestic refrigerator. The measured reduction in energy consumption is reported as well as the effects of voltage on cycle temperatures, pressures, flow rates and also compressor speed (revolutions per minute). A domestic refrigerator using R134a as refrigerant, having a capacity of 150L and power rating of 100W was used in the experiments. Two energy consumption procedures were adapted from the JIS and ISO standards. The most notable difference between the two tests is that the fridge is not opened in the ISO test while it is opened a number of times in the JIS test. The tests were carried out between 190V and 250V in steps of 10V. It was noted from the experiments that the energy consumption does decrease with a decrease in voltage. A maximum drop in energy consumption was registered between 200V and 240V. The reduction was of 49.78Wh per day or 6.27% of the total consumption. These small differences in consumption are negligible when converting them into kWh, which is the billable unit. Considering the price of electricity of say 0.20€, a saving of 3.41€/year was calculated for the tested refrigerator, calculated at the highest drop in energy consumption. The variation of instantaneous power with voltage was also noted. Furthermore it was noted that the compressor ON-time between 190V and 250V varied by an average of 8 seconds (as expected, the compressor remains on for a longer time at 190 V). It was noted that that the longer ON-time has negligible effect on the energy consumption. In conclusion it was noted that a decrease in voltage will result in a small decrease in energy consumption.