A parametric study of thermoelectric generator system under low temperature gradient condition

초록

Direct energy conversion from nature to electricity is important to obtain the renewable energy from environment. To fulfill the increasing demand for eco-friendly energy, various renewable energy technologies such as photovoltaic cell, windpower, solar-heat, geothermal, tide wave power technologies, have been suggested and developed. Among them, thermoelectric power generation, which converts directly heat gradient into electrical energy through the Seebeck effect, have emerged as a promising approach because it has the advantage of high reliability, scalability, silent operation, absence of moving mechanical parts and wide range of operating temperature [1]. Based on these advantages, thermoelectric power generation is used for various kinds of industry such as automobile, space probes, and power plant. In addition, thermoelectric power generation can improve overall efficiency of thermodynamic system when it can be used for waste heat recovery. To harvest the potential energy under a low temperature difference such as OTEC, we designed small scaled power generation system based on commercialized thermoelectric generators (TEG). Also we studied to analyze the TEG energy harvesting system, which consists of various components such as heat exchanger design and structure, thermal interface material (TIM) between TEG and heat exchanger and insulating layers. The working fluid flows into the two heat exchangers, which can transfer the thermal energy to/from the TEGs and the DC power was generated by the temperature difference between the two sides of the TEGs. In order to improve the thermoelectric power generation performance, experiments under various conditions have been conducted: thermal conductivity of thermal interface material, thickness of thermal interface material, gap between thermoelectric generators, and different connections of wiring among the TEG [2].