Flat heat pipes for potential application in fuel cell cooling

A thin flat heat pipe is proposed as a reliable alternative for Proton Exchange Membrane Fuel Cell (PEMFC) cooling. The flat heat pipe includes a sealed casing with two microgrooves to provide the required capillary pumping of the working fluid. Deionized water was used as the working fluid. In this work, a numerical and experimental analysis is presented. A heat transfer model is proposed to evaluate the capillary limit, the operating temperature and the required working fluid inventory. The main goal is to cool the PEM fuel cells to ensure a suitable operation in the required temperature range between 70 and 90 °C with small thermal gradient. The proposed control system consists of a set of stainless steel flat heat pipes, with 100 mm length, assembled in parallel. The tests showed that proposed heat pipe was able to dissipate up to 12 W, corresponding to 1.8 W/cm2 at evaporator section, ensuring a suitable PEMFC operation.