Experimental and Numerical Investigating a New Configured Thermal Coupling between Metal Hydride Tank and PEM Fuel Cell Using Heat Pipes

Abstract This paper presents an experimental investigation of a fuel cell coupled with the metal hydride (MH) tank to study the effects of heat pipe number, wire number and the type of heat pipes with and without fin. The effect of the number of heat pipes and fins, as well as the number of copper wires as a wick layer, has not been investigated in previous similar studies The computational fluid dynamics (CFD) calculations were carried out using the finite element method (FEM) in COMSOL. Some parameters including condenser length, adiabatic length, evaporator length, heat pipe diameter and heat pipe power were optimized. In the experiments, 30 and 40 strands of copper wire were selected as the wick layer and experiments were repeated for 5 and 10 finned heat pipes. Experimental results also compared with simulation data and it was found that results were consistent with little deviation. By using the relative deviation method, the deviations amounting to 7.45 % and 6.76 % were obtained in adsorption and desorption step, respectively. Also, sensitivity analysis of the capillary limit and wire diameter of heat pipes were carried out and results illustrated that the reduction of boiling limit has a more significant impact on the heat pipes thermal power than the capillary limit and wire diameter. Response surface methodology was used which showed that the best performance of the desorption process at 25 bar is achieved using 4 heat pipes covered by 10 fins.