Improving transient performance of thermoelectric generator by integrating phase change material

Abstract

Thermoelectric generator (TEG) based on Seebeck effect, which is well regarded as an effective way for waste heat recovery, has stepped into vision of automotive researchers in the past decades in terms of electricity generation from vehicle exhaust gases. Various driving conditions of the vehicles and fluctuating temperature of the exhaust gases are crucial factors that obstruct the development of automotive TEG. In this study, a novel concept of integrating phase change material (PCM) with TEG for improving transient performance and total efficiency is presented. PCM, as a commonly utilized material for thermal energy storage, reduces the impact of exhaust gas temperature fluctuations on the automotive TEG, thereby improving the efficiency under various driving conditions. According to the thermal properties of the exhaust gases, Pentaerythritol (PE) is selected as the appropriate PCM for the automotive TEG, because of the suitable temperature range for phase transition and extremely low rate of volume change during the phase transition (due to its solid-solid phase change). Experiments are conducted to explore the feasibility of PE integrating with TEG and the capability of improving transient performance of TEG. Results showed that the improvement of open circuit voltage and power output are 0.7% and 1.16%, respectively. The present study provided a guideline for the design and further research of PCM integrated automotive TEG.