Abstract: This invention is directed to coolant compositions, particularly coolant compositions useful n fuel cells, and to fuel cells containing such coolant compositions. The coolant compositions or heat transfer fluids of this invention have and retain low electrical conductivity through extended periods of use. These coolant or heat transfer fluids are composed of a base composition and an additive package which imparts the property of retaining low electrical conductivity for extended periods of time. The base composition can be de-ionized water (DI water) alone or a mixture of DI water and a freezing point depressant of the types well-known in the art (e.g., propylene glycol). The additive package contains an organic corrosion inhibitor and a polymeric ion suppressant. The use of both components of the additive package is important.

Abstract: A heat transfer fluid composition and process employing composite mixtures of terpenes and silicones useful for heat transfer processes in a temperature range down to ?200° F., where the fluid heat transfer composition retains its liquid phase over the entire temperature range.

Abstract: Heat transfer fluid compositions comprising (a) a terpene component, comprising at least one terpene; and (b) an alkylbenzene component, comprising at least one alkylbenzene; wherein the components are provided in an effective amount such that the 5resultant composition retains the liquid phase at temperatures in the range from about 0.degree. F. to below about -120.degree. F., preferably from about 0.degree. F. to about -175.degree. F.