As high-quality food preservation has become an important aspect of daily life, a need has developed for domestic household refrigerators with a wide refrigeration temperature range. The temperature range of domestic household refrigerators is generally above -20 °C. However, a wide temperature range of -18 to -60 °C is required for a domestic household refrigerator, especially for the freezing preservation of high-quality foods such as Kobe beef, dried abalone, and ocean-going tuna. In this study, a hybrid refrigeration system that combined vapor compression refrigeration (VCR) and a thermoelectric refrigerator (TER) is investigated for the freezer compartment of a domestic refrigerator with a volume of 0.018 m3. The VCR evaporator and TER are connected in series to form the hybrid system with a compact structure and little noise. In this hybrid system, the evaporator of the VCR system is connected to the hot side heat exchanger of the TER, and the cold side of the TER achieves a lower temperature than that in the evaporator of the VCR system. Therefore, a VCR system combined with a TER can achieve a low temperature in the freezer compartment of a domestic household refrigerator. The performance of this hybrid refrigeration system was investigated experimentally, and then a three-dimensional numerical simulation was used to optimize the finned heat sink on the cold side of the TER.The hybrid refrigeration system combining VCR and TER is experimentally studied. Although an additional 99.5 W of electrical power is consumed, a lower temperature of -38.1 °C is experimentally achieved in the deep freezer compartment of a compact VCR–TER system, with no noise or mechanical parts. In contrast, a temperature of only -8.8 °C is obtained in a typical VCR system. A three-dimensional numerical model is applied to study the performance of the finned heat sink of the TER using FLUENT. The effects of the fin height and fin pitch on the thermal resistance and pressure drop are investigated using numerical simulations. The results show that the thermal resistance decreases with an increase in the fin height and increases with an increase in the fin pitch. An optimized finned heat sink with a fin height of 50 mm is obtained, which has a thermal resistance of 0.05 °C/W. It has a higher cooling capacity of 53.6 W than the heat sink with the original fin height of 30 mm. The VCR–TER system has potential application to low-temperature domestic refrigeration systems with a small size and small cooling capacity.

Experimental and Numerical Study on Performance of Vapor Compression Refrigeration System Combined With Thermoelectric Refrigerator

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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