The theoretical model of thermal resistance for flat-plate CLPHP and its heat transfer performance in PEMFC cooling

The temperature control and uniformity are important factors that determine the coupling efficiency of the flat-plate closed loop pulse heat pipe (CLPHP) integrated zero carbon proton exchange membrane fuel cell (PEMFC) cooling. Based on the structural features of the flat-plate CLPHP and the thermodynamic properties of the working fluid, a theoretical model for axial heat transfer resistance is established. The calculation accuracy of the segmented and integral thermal resistance models is compared through experiments. Additionally, it determines the effect of the surface heat transfer coefficient in the condensation section on the heat transfer power of the CLPHP as well as the transverse and longitudinal working temperatures of the PEMFC. The results indicate that increasing the thermal conductivity of the flat-plate CLPHP shell and reducing the flow resistance of the vapor-liquid working fluid can enhance its heat transfer power. Additionally, the segmented heat transfer resistance model exhibits a higher calculation accuracy; The integration of the flat-plate CLPHP into the PEMFC bipolar plate ensures the ideal operating temperature and temperature uniformity of the PEMFC. Fins can be added to enhance the surface heat transfer coefficient of the condensation section of the flat-plate CLPHP, meeting the cooling requirements of multiple single cells.