Passive thermal coupling of PEM fuel cells and metal hydride hydrogen storage systems using heat pipes

The PEM fuel cell heat can be used to enhance the hydrogen discharging rate of Metal Hydride (MH) hydrogen storage canisters. This is while at higher power operating points (i.e. when more fuel cell heat is also available) the fuel cell demands for more hydrogen flow from MHs. This situation supported the idea of studying passive thermal bridging of PEM fuel cells and MHs by using heat pipes that is the focus of the present PhD research. A mathematical model was developed to simulate the details of this thermal bridging. The results showed that around 30% of the total fuel cell cooling load is enough to match the MH hydrogen supply and the fuel cell demand rates, while the fuel cell's average temperature can be maintained at a desirable range of 55-65°C. This theoretical investigation was complemented by a numerical study to analyse the temperature distribution in the PEMFC and MH canisters. A mimicking as well as a small-scale experimental setup (four cells with one cooling plate and one MH canister) were designed to experimentally investigate the practical feasibility of this thermal coupling arrangement and also to validate/modify the mathematical model created earlier as part of this study.