Passive fuel cell heat recovery using heat pipes to enhance metal hydride canisters hydrogen discharge rate: an experimental simulation

This paper reports on an experimental investigation of a passive thermal coupling arrangement between a Proton Exchange Membrane (PEM) fuel cell and a Metal Hydride (MH) hydrogen storage canister using heat pipes for enhancing the release rate of hydrogen. The performance of this arrangement was measured by inserting the evaporator sections of the heat pipes into an aluminum plate mimicking one out of five cooling plates of a 500-W fuel cell (that is a 100 W section of the stack). Thermal pads were attached on both sides of the plate to represent the fuel cell heat to be supplied to a 660-sl MH canister. The results showed that the operating temperature of the fuel cell can be maintained in the desired range of 60-80 °C. A complementary experimental study was also conducted on an 800-sl MH canister supplying hydrogen to a 130-W fuel cell stack (a slightly scaled-up setup compared to the first experiment). The study confirmed the findings of an earlier theoretical study by the authors that by supplying about 20% of the total cooling load of the stack to a MH canister, its maximum sustainable hydrogen supply rate increased by 70%, allowing for continuous operation of the stack at its rated power.