AN EXPERIMENTAL STUDY ON THE EFFECT OF A NEW DEFROSTING STRATEGY ON THE ENERGY CONSUMPTION OF HOUSEHOLD REFRIGERATOR

Fernando T. Knabben¹; Claudio Melo¹

¹ UFSC

doi:10.20906/CPS/COB-2015-0220

Resumo

In a previous work an experimental testing apparatus was constructed and used to measure the defrosting efficiency of different heaters working under different control strategies. Based on such work two defrosting heaters, namely the calrod and the distributed, and two control strategies, the constant power and the steps mode, were selected for this work. In the constant power (original) mode the power was held at 160 W during 17 and 19 min with the distributed and calrod heaters, respectively. In the steps mode, in turn, the power was gradually reduced from 160 to 20 W in four 40 W steps, and the defrosting time was set to 29 and 22 min with the distributed and calrod heaters, respectively. Energy consumption tests were carried out following the ISO and AHAM standards, using the same top-mount frost-free refrigerator. Changes were introduced in the electronic board in order to vary the power and length of the steps. A glass window was also installed at the rear wall of the refrigerator to visually check the defrosting process. A 4% drop in both ISO and AHAM energy consumptions was achieved by replacing the calrod heater with the constant power mode by the distributed heater with the steps mode. Clogging tests were also carried out, using an automatic door opening device to check the robustness of the different defrosting systems.

Palavras-chave: defrost; heater; evaporator; refrigerator; energy consumption