Design and experimental study on performance of different types of micro heat pipe arrays for thermal management of a novel mixed-cooling proton exchange membrane fuel cells stack

This study proposes a new mixed-cooling micro heat pipe array–proton exchange membrane fuel cell (MHPA-PEMFC) stack by developing and assembling three different shapes and new structures of MHPA. This concept effectively solves heat dissipation under high-temperature conditions and during preheating in a low-temperature environment of the PEMFC field without increasing the fan configuration and parasitic power of the stack. The performance of the three MHPAs is experimentally tested. Results show that the three types of MHPAs fully satisfy the thermal management requirements of PEMFC stacks. The double-rectangle MHPA exhibits the minimum thermal resistance of 0.18 °C/W, and the rectangle MHPA exhibits the minimum dynamic thermal response time of 100 s. The heat transfer characteristics of MHPAs can be enhanced by attaching fins, reducing ambient air temperature, and increasing cooling air velocity. The temperature difference of the MHPA can decrease by 17.7 % with fins. The thermal performance of MHPAs at high ambient temperature is worse than that at low ambient temperature. As the cooling air velocity increases, the thermal resistance of the rectangle MHPA, parallelogram MHPA, and double-rectangle MHPA decreases to 140 %, 117 % and 117 %, respectively.