Influence of pressure drop in PEM fuel cell stack on the heat and mass balances in 100 KW systems

Proton Exchange Membrane (PEM) fuel cell systems have been studied as the alternatives of the internal combustion engine systems. However, these systems are not appearing in daily life yet, due to the high cost, shortage of infrastructure, technical issues, etc. Concerning technical issues, water/thermal management is a critical one to keep high proton conductivity in the electrolyte membrane for the design of PEM fuel cell systems. Therefore, the heat and mass balances in the PEM fuel cell system have been studied for a long time. However, the influence of stack design on the power and heat generation have not been deeply discussed yet. In this study, influence of the pressure drop and maldistribution in a PEM fuel cell stack on the heat and mass balance in the 100 kW systems was studied. It has been found the heat load in the radiator is reduced by the consideration of the pressure drop in the stack. This is because of the reduction of the water condensation in the stack. The amount of heat, which is reduced in the radiator, is mostly shifted to the condenser for the water recovery. As a conclusion, it can be argued that, by involving the influence of pressure drop in the stack, the amount of heat load in the radiator is reduced about 5%. This is mostly due to less water condensation in the stack. This reduced heat is shifted to the condenser. It corresponds to about 10 % increase in the heat load in the condenser. The design of the radiator and condenser must consider this shift in heat load due to the pressure drop in the stack.