Potential Usage of Thermoelectric Devices in a HTPEMFC System: Two Case Studies

Methanol fuelled high temperature polymer electrolyte membrane fuel cell (HTPEMFC) power systems are promising as new generation vehicle engines, efficient and environmentally friendly. Currently, they still rely on large Li-ion batteries for system startup. In this paper, the application potential of thermoelectric (TE) devices to release this Li-ion dependence has been preliminarily evaluated. Firstly, following the HTPEMFC stack or the methanol reformer, TEGs are embedded inside a gas-liquid heat exchanger to jointly form a TE recovery subsystem for electricity production. A finite-difference model of this subsystem has been built in engineering equation solver (EES) software for optimization. The results show that the recovered power can significantly reduce the dependence on Li-ion battery during startup, especially when this TE subsystem is directly installed after the methanol reformer. Secondly, TE coolers are integrated into the methanol evaporator to reduce the heat loss herein during the HTPEMFC power system startup. It is believed that by reducing this heat loss, the electricity consumption by the evaporator during startup can be steadily reduced. Through the heat-electricity conversion and the TE-assisted heat-loss reduction, the HTPEMFC system dependence on Li-ion battery during startup can be dramatically reduced. The preliminary analyses show that TE device applications inside HTPEMFC power systems are of great value and worth of further studies.