Increasing electricity generation and reducing performance fluctuations in thermoelectric generators using phase change materials

This paper proposes a thermoelectric generator (TEG) that integrates a phase change material (PCM) between the heat exchanger and the thermoelectric module, evaluating the potential of PCM in attenuating output power fluctuations and enhancing net power generation under real-world vehicle driving cycle conditions. A transient CFD and thermoelectric hybrid numerical model, incorporating the phase transition process of the PCM, is established to optimize PCM's heat transfer performance. Besides, this study proposes the fluctuation coefficient (Fc) as a novel evaluation metric to measure the degree of fluctuation in TEG's performance parameters. The results show that PCM can reduce the TEG power fluctuation coefficient by up to 32.81 %, but this improvement is accompanied by a significant decrease in output power. Introducing fins improves the PCM's heat transfer performance, thereby mitigating the power loss. Besides, the use of PCM can boost the additional power generation of TEG by up to 27.77 %. Through optimization of PCM heat transfer performance, this study reduced the TEG's power fluctuation factor by 5.71 %, increased its total electricity generation by 3.23 %, and improved its effective conversion efficiency by 2.19 % in the optimal scenario. These findings provide theoretical insights for the design and thermal optimization of PCM-TEG under dynamic operating conditions.