Experimental study on the performance of a gravity-driven medium-temperature separated thermosiphon-thermoelectric generation coupled system

Traditional thermoelectric power generation systems suffer from problems such as low heat transfer efficiency and concentrated thermal stress. Existing thermosyphon-thermoelectric generation technologies are mainly limited to low-temperature waste heat recovery and physical nested designs, with insufficient research on medium-to-high temperature heat sources and deep coupling. To address this, this paper proposes a Gravity-Driven Medium-Temperature Separated Thermosiphon-Thermoelectric Generation Coupled System(G-MSTS-TEGS). By separating the evaporator and condenser sections and combining a phase change working fluid (Dowtherm A) cycle with a heat pipe-enhanced heat transfer mechanism, the system achieves a synergistic optimization of heat flux density and the Seebeck effect. The experimental system consists of heating module, liquid storage tank, thermoelectric power generation systems, and cooling unit, and explores the system's startup characteristics, temperature distribution, and heat transfer performance under varying heating power and collector installation angles. The results show that: the thermal equilibrium time of the system significantly shortens as the heating power (0-3KW) increases, with the maximum output power reaching 66.7 W and the highest thermoelectric conversion efficiency of 2.22% the temperature distribution inside the collector is uniform (temperature difference < 15°C), with localized surface temperature fluctuations but overall controllable (150-180°C) as the angle increases, the system startup time increases, the power generation capability of the system enhances, and the system's thermal adaptability improves both the boiling and condensation heat transfer coefficients increase with power, and the total thermal resistance decreases. This research provides a novel technological pathway for medium-to-high temperature waste heat recovery and lays the experimental foundation for the integration and optimization of thermoelectric coupled systems.