The principle of Proton Exchange Membrane (PEM) fuel cell technology involves reaction of hydrogen and oxygen near the membrane to produce electricity, and PEM fuel cells are being adopted to drive automobiles carrying wide range of loads. Some heat is also generated along with electricity due to the reaction in PEM fuel cell, and it must be dissipated to surroundings to maintain required operating temperature which is vital for efficient operation of the PEM fuel cell. Conventionally, liquid coolants are used to cool the PEM fuel cells, which require considerable pumping power. It is crucial to reduce the pumping power, and one way is to rely on passive cooling technologies like heat pipes. Heat pipes are widely used to dissipate heat from narrow heat generating spaces by working on the principles of phase change and capillary forces. The working fluid in the heat pipe, evaporates by taking the heat in the evaporator section, and condenses by rejecting heat to surroundings in the condenser section. The condensed liquid travels back to the evaporator section through the capillary wicks. Recent studies have shown that heat pipes, when integrated into PEM fuel cells, lead to reduced operating temperatures, improve temperature distribution, and increase the current density of fuel cell, also avoid the pumping power and associated losses. In the present study, we have evaluated the heat dissipation capability of heat pipes using a validated mathematical model. This model is used to perform parametric studies with different lengths, different working fluids and orientations of heat pipe, and the corresponding heat dissipation capacity and thermal resistance values are reported.
Karlapalem et al. (Thu,) studied this question.