Experimental study on waste heat recovery of refrigeration system for closed-loop heat sink thermoelectric generator

Abstract

In this paper, thermal to electrical using waste heat recovery from a refrigeration system is utilized to generate electricity through a closed-loop heat sink thermoelectric generator (TEG) is presented. The concentric tube heat exchanger is used to take the waste heat from a refrigeration system to produce hot fluid for TEGs. The cold fluid is produced by a refrigeration system used for cooling the cold side. The hot and cold sides of the TEGs are coupled with heat sinks where hot and cold fluids flow through the heat sink channel to generate electricity. The effects of the fluid flow, and on/off modes of the refrigeration system, are investigated. It was found that the output voltage depends on the operating behavior of the refrigeration system, and operating time when on mode and off mode directly affects a hot fluid temperature fabrication. Applying fluid mass flow rate on the hot side and the cold side is very important that may cause the output voltage to be enhanced. The maximum temperature difference was obtained for the long-running refrigeration test mode. For on mode and off mode, the operating time of 10 minutes is the greatest to obtain the minimum and maximum temperature difference of 19.80°C and 13.10°C to get the maximum and the minimum output voltage of 9.80 V and 5.67 V. Besides, the cooling efficiency of the refrigeration system was increased and reduced power consumption by approximately 23% as integrated with the TEG system. Cooling capacity (Qc) and COP of the refrigeration system equipped with TEG increased by approximately 40% over traditional refrigeration system. Excess heat from the cooling system is recovered and converted into electricity. This is an energy-saving alternative that may help reduce the global warming crisis. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.