# Design and Research of Thermoelectric Generator Simulation System for Boiler Flue Gas Waste Heat
## 6 Conclusions  
As a green power generation method, TEG provides a new idea for energy conservation and environmental protection. Taking The waste heat of low grade boiler flue gas as the research object, the overall design scheme of TEG system is designed in this paper. An experimental device was set up to simulate the temperature condition of flue gas waste heat. During the experiment, the fixed temperature difference was set at 120 \({}^{\circ}\)C (hot end: 150 \({}^{\circ}\)C-cold end: 30 \({}^{\circ}\)C), and the output characteristics of TEG system are analyzed. 1. The uniformity of temperature distribution at the hot and cold ends of the TEG module affects the output power, and the coating of thermal grease on the thermoelectric plate can effectively improve the uniformity of temperature distribution. The evenness of temperature distribution at both the hot and cold ends of the TEG module has an impact on the output power. Applying a layer of thermal grease on the thermoelectric plate can effectively enhance the uniformity of temperature distribution. The use of water cooling heat dissipation and higher peristaltic pump speed can effectively maintain the temperature difference and increase the output efficiency. To enhance the output efficiency and maintain the temperature difference, utilizing water cooling heat dissipation and elevating the peristaltic pump speed are effective measures. To accommodate the extended operational duration of the double-headed peristaltic pump and the lifespan of the silicone tube, the pump's velocity is established at 280 r/min. The velocity of the double-headed peristaltic pump has been set at 280 r/min to ensure the extended operational duration of the pump and the lifespan of the silicone tube. 2. Under the same conditions, the maximum power of 20 thermoelectric plates in series is slightly greater than that of parallel combination. This is due to the error caused by the uncertainty of temperature and the uneven transverse temperature distribution of a single TEG. 3. In traditional medium to high temperature TEG systems, it is generally believed that the maximum output power of the system is achieved when the load resistance is  
Figure 26: Comparison of simulation results of two MPPT algorithms. equal to the internal resistance of the TEG module. Typically, in traditional medium to high temperature TEG systems, it is commonly believed that the maximum output power of the system can be attained when the load resistance is equivalent to the internal resistance of the TEG module. In the experiment, it was found that when the fixed temperature difference is set to 120 \({}^{\circ}\)C, the maximum output power is generated when the load resistance is slightly greater than the internal resistance, and the ratio of the load resistance to the internal resistance is about 1-1.15. Therefore, it is necessary to consider not only the influence of electric energy, but also the influence of heat energy for TEG module. When TEG is loaded, Partier effect and Thomson effect are produced, and the larger the temperature difference, the more obvious the phenomenon. 4. In order to output the maximum power, an adaptive variable step size improved MPPT algorithm based on power prediction is designed. According to the simulation results, the time taken by the improved algorithm to achieve the stable maximum power point is approximately 0.21 s, whereas the traditional algorithm takes around 1.75 s to reach the stable maximum power point. The time of the improved algorithm to reach the stable maximum power point is 1.54 s faster than that of the traditional algorithm. So the improved algorithm can reach the stable maximum power point more quickly and with less fluctuation than the traditional algorithm. The improved MPPT algorithm can meet the requirements of rapidity and stability accuracy of TEG system and reduce the energy loss. The designed TEG system can meet the requirements of waste heat recovery, and it has a broad application prospect in low grade energy utilization.