Technical Issues Governing the Selection and Development of Dielectric Coolants for Fuel Cell Systems

The selection of a heat transfer fluid that meets all of the requirements for fuel cell operation is daunting. There are multiple competing fluid properties needed for optimal performance: high dielectric strength, low ionic and electronic conductivity, high heat capacity, high thermal conductivity, low viscosity at low temperatures, high flash points, low toxicity and no reactivity with contacting materials. In this paper we report the results of our evaluation of numerous basic and commercial heat transfer fluids with respect to their prospective fuel cell performance. We have also examined some of the fundamental physical and chemical properties of fluids to provide guidance on engineering a fluid based temperature regulation system for a fuel cell stack.