Investigating and establishing limiting heat flux for passively cooled and solar concentrated thermoelectric power generation system
Creators: name: Date, Ashwin Shridhar
Publisher: name: RMIT University
Year: 2024

description: Thermoelectric generators (TEG) working on the principle of Seebeck effect have gathered the attention during this period as a potential device that can generate electricity in a sustainable way. Thermoelectric generators produce high open circuit voltage at high temperature difference across its hot and cold side. High temperature can be achieved by applying large heat flux on the hot side of TEG and low temperature on the cold side will needs effective heat sink. Commercially available thermoelectric devices have low figure of merit which lead to low conversion efficiency. This restricts the user from using the active cooling systems on the cold side to lower the temperature for better thermoelectric power generation. Therefore there is an inherent need to find the suitable passive cooling technique for the commercially available thermoelectric generators. The primary aim of the research is to investigate the conventional passive cooling techniques and find the limiting heat flux that can be reached for commercially available thermoelectric generators with these conventional passive cooling methods. Further this research introduces and explores a novel passive cooling technique using the heat pipe for cooling of commercially available thermoelectric generators. Two commercial thermoelectric generators are selected for testing with the conventional passive heat sinks and the innovative non-conventional heat sink for cooling. Indoor experimental setup uses cartridge electric heaters embedded in the aluminium block to achieve the high heat flux. Outdoor experimental setup consists of a Fresnel lens to achieve the high heat flux for hot side of thermoelectric generator. Conventional heat sink configurations include bare plate as heat sink, finned heat sink and heat pipe finned heat sink. A novel and non-conventional passive heat sink is proposed this research which uses heat pipes to transfer the heat away from the cold side of thermoelectric generators and dump the heat into water instead of just cooling it with air. This system also opens an avenue for the utilizing the dumped heat in the water for industrial or household purpose. A case study with application of this non-conventional heat sink is presented in this research for a remote area house. System is designed and analysed for electricity and hot water demand fulfilled by using solar concentrator system for high heat flux with thermoelectric generators for electricity generation and passive water cooled heat pipe heat sink for hot water demand of the remote area home. In conclusion limiting heat flux for two commercially available TEG’s is established for conventional passive heat sinks. A non-conventional passive heat sink is introduced for cooling of TEG’s and heat flux capabilities for this heat sink with two TEG’s are established. It is shown that the thermoelectric power generation has a bright future to get into small to medium scale mainstream power generation with existing figure of merit of the materials. Further research and development in the field of materials can lead to higher figure of merit for thermoelectric materials that can compete with the existing conventional heat engines mainstream large scale power production.<br>