Investigation On Performance Characteristic Of Hybrid System Based On Two-Stage Thermoelectric Generator

The sustainable development of energy and ecological environment is a necessary condition for human survival and development,so the development of efficient and clean green energy is of great significance.The thermoelectric generator is a kind of green and clean energy equipment which can directly convert heat energy into electric energy.It has the advantages of small size,no noise and no rotating parts.In addition,the thermoelectric generator plays a huge role in the field of waste heat recovery and power generation.It can adapt to a wide range of heat source temperature and effectively recover various types of heat,such as industrial waste heat,internal combustion engine waste heat and fuel cell waste heat.The research showed that the performance of the twostage thermoelectric generator was better than that of the single-stage thermoelectric generator in the environment of high temperature heat source and large temperature difference.However,there is little research on the hybrid system of the two-stage thermoelectric generator and high temperature heat source.Therefore,this paper proposes and analyzes two hybrid systems based on the two-stage thermoelectric generator with excellent performance,in which the function of the two-stage thermoelectric generator is to recycle and reuse high-grade waste heat to achieve additional power generation.Firstly,this paper introduces the research background of the thermoelectric generator.The basic working principle and technical development of the research object is described,which shows the significance and development potential of the hybrid system based on the two-stage thermoelectric generator.Secondly,the hybrid system model of direct carbon fuel cell and two-stage thermoelectric generator is established.Basing on the theory of non-equilibrium thermodynamics and finite time thermodynamics,the mathematical expressions of the output power and equivalent efficiency of the hybrid system are derived,and through numerical simulation,the output power density and efficiency of the coupling system model are increased by 52.21% and 51.73% respectively compared with the single direct carbon fuel cell system.The optimization interval of relevant design parameters is obtained via the detailed parameter analysis of the hybrid system.The results show that the performance of the system can be effectively improved by using the two-stage thermoelectric generator to recover waste heat for power generation.The results of the study provide some important reference suggestions for the optimization of performance parameters,and provide reference for the design of hybrid system.And then,the hybrid system model of alkali metal thermal electric converter and two-stage thermoelectric generator is established,and the mathematical expression of the output power and efficiency of the hybrid system is derived.The optimization conditions of the hybrid system at the maximum output power density and maximum equivalent efficiency are determined.The alkali metal thermal electric converter and two-stage thermoelectric generator are obtained the optimal matching of the design parameters of the thermoelectric generator is discussed.The influence of some important performance parameters on the system performance is discussed.The results of numerical simulation show that the output power density and efficiency of the coupled system model are 54.09% and 28.09% higher than that of the single alkali metal thermal electric converter system.The research shows that the two-stage thermoelectric generator can effectively utilize the high-grade waste heat generated by the alkali metal thermoelectric generator and improve the energy utilization efficiency of the hybrid system.Finally,the work of this paper is summarized,and some suggestions and prospects are put forward.The results obtained provide some theoretical guidance for how to effectively use the medium and high temperature heat sources for the two-stage thermoelectric generator.