Experimental analysis of hybrid household refrigerators including thermoelectric and vapour compression cooling systems

Abstract

Two different hybrid refrigerators which include vapour compression and thermoelectric (TE) cooling technologies were built and tested. Serial refrigerators, which use vapour compression only were first tested to collect reference data for comparisons. Then, the hybrid prototypes were constructed by attaching thermoelectric coolers (TECs) to different compartments of these serial units. Among the chill, fresh food and freezer compartments of the refrigerators, the TECs were only used at chill and fresh food compartments, which have different cooling power requirements. Energy consumption, cooling and freezing capacity, and noise tests were conducted in compliance with three different standards.All hybrid refrigerators operated successfully in various ambient temperatures and loading conditions. The test results showed that the hybrid refrigerators had at least three times higher energy consumption levels over those of serial ones, because of the lower operating efficiencies of the TECs and higher transmission losses. Moreover, their noise levels are extremely high, at least 25 dB(A) higher than those of serial ones. However, the TECs provided a more sensitive temperature control in the compartment in which they were used. Additionally, the hybrid refrigerators’ performance in terms of cooling capacity was very promising. They were able to cool 17.5 kg of loads from an ambient temperature of 25 °C to the desired temperatures faster than the original serial refrigerators. Since the freezer compartments of both the serial and hybrid units are cooled by compressor-based cooling systems, the freezing capacity results were identical.