Mardit Matian

An experimentally validated heat transfer model for thermal management design in polymer electrolyte membrane fuel cells

Abstract The temperature distribution in polymer electrolyte membrane fuel cells (PEMFCs) plays a vital role in defining the overall efficiency and in ensuring the delivery of optimum performance, and understanding the heat transfer taking place is essential for the design of effective thermal and water management systems. This article describes a simple model, validated against experiment, which can be used to investigate the factors such as bipolar plate design, materials of construction, and the external effects of forced convection such as cooling fans and natural convection. The model employs computational fluid dynamics to account for the reactant flows in composite graphite plates and heat distribution within the stack, while convective heat transfer from the external surface of the fuel cell is treated using well-known heat transfer correlations. The computational model was validated using a novel fuel cell analogue composed of an electrically controlled heating plate to simulate the heat generated by the membrane electrode assembly and instrumented with 14 calibrated thermocouples. The model showed good agreement with the experiment over a wide range of gas flowrates, both in terms of local temperature distribution and overall energy balance. This suggests that the novel experimental methodology reported here could be used to support the design of bipolar plates for optimum heat transfer.

Thermal Management Issues in Fuel Cell Technology

Fuel cells are electrochemical energy conversion devices that convert chemical energy in fuels directly into electrical energy, without the process of combustion. As a result, they are not constrained by the thermodynamic limitations of heat engines and therefore have the potential to achieve higher efficiencies. Various fuel cell types exist, operating from room temperature to over 1000 °C. This paper focuses on two of the leading fuel cell types, namely the lower temperature (80–120 °C) polymer electrolyte membrane fuel cell (PEMFC) and the higher temperature (500–1000 °C) solid oxide fuel cell (SOFC), with particular attention paid to the importance of thermal management and heat transfer in these systems, as it is thermal transients, and the appropriate design of the thermal management sub-system, that frequently limit fuel cell system performance and durability. Two examples of research from the authors’ laboratories are given; the first relates to the measurement and modelling of heat transfer in PEMFCs; the second to the thermal management of SOFCs.Copyright