# Design and Research of Thermoelectric Generator Simulation System for Boiler Flue Gas Waste Heat
## 1 Introduction
[18] used COMSOL software to study the multiple physical fields of a photovoltaic-thermoelectric hybrid system and to determine the optimal geometry of the thermoelectric element. [PERSON] et al. [19] used the minimum breaking load to obtain the open-circuit voltage of the TEG module, which can achieve a tracking efficiency of 93%. [PERSON] et al. [20] found that when TEG modules were applied to large area of heat sources, and there was always the problem of uneven temperature distribution at the hot end, which reduced the overall power output of the system. [PERSON] et al. [21] used GT-SUITE software to conduct numerical modeling to study the thermoelectric effect, and found that the generation power of thermoelectric modules with mixed series-parallel connection was greater than that generated by a single series or parallel connection. [PERSON] et al. [22] built a calculation model for circular chimneys, and the predicted power generation accuracy of this model is 12%. [PERSON] et al. [23] proposed a method for measuring contact thermal resistance at low temperature. [PERSON] et al. [24] optimized the structure of industrial smoke exhaust pipes by changing the inclination Angle, and found that the output power could be increased by 5% when the inclination Angle was 15 degrees. Previous reports mainly focused on the application of TEG technology, structural parameters optimization of TEG model, MPPT control, etc. Most of their applications belong to the recovery of waste heat at medium and high temperatures (above 200 \({}^{\circ}\)C), which is relatively easy to recover. For low temperature heat source (below 200 \({}^{\circ}\)C), the energy utilization efficiency is also lower due to its lower energy quality. Due to the limitation of production cost and conversion efficiency, there are no reliable products for large-scale commercial application, and the recycling technology is not yet mature. The exhaust gas temperature of power station boilers is mainly concentrated between 120-150 \({}^{\circ}\)C, which belongs to the range of low-grade waste heat. At present, there are few researches on the application of TEG technology to low-grade waste heat of power boiler flue gas. Moreover, the detailed matching relationship between external load resistance and internal resistance of TEG module is rarely reported when the TEG system generates maximum output power under the condition of low grade waste heat. In this paper, a semiconductor TEG simulation system is designed to convert waste heat from industrial boiler flue gas into electric energy. On the basis of optimizing the structure of TEG module, the relationship between the load resistance and the internal resistance of the module is studied when the maximum power is generated by the boiler flue gas waste heat TEG system. An improved maximum power point tracking (MPPT) algorithm is proposed to reduce the energy loss of the system. The system can also indirectly output domestic hot water to reduce fuel costs. Therefore, it can improve energy efficiency and has high economic benefits. The research can provide technical reference for the application of TEG technology in the field of low-grade energy recovery.