SBIR-STTR Award

Due to the inherent inefficiencies of Proton Exchange Membrane (PEM) fuel cell stacks, a coolant must be used to remove the waste heat produced by the fuel cell. Deionized (DI) water or glycol/water solutions with a deionizing filter are commonly used as a fuel cell system coolant. Although these fluids are non-flammable and thermophysically efficient, the electrical conductivity increases rapidly, requiring frequent replacement of the deionizing filters and increasing fuel cell operating costs. This problem will be addressed by developing a complex coolant fluid comprised of a base composition and an additive package. The base composition addresses the non-flammability, heat transfer, freezing point, and materials compatibility issues, whereas the proposed additive package will maintain the electrical conductivity of the coolant below a certain level for 2 to 3 years. In Phase I, key ingredients of the additive package will be prepared and incorporated into the coolant fluid. The resultant complex coolant fluid formulations will be tested in a dynamic loop to determine the effectiveness of the additives in keeping the electrical conductivity of the coolant below 2 mS/cm.

Commercial Applications and Other Benefits as described by the awardee:
The new complex coolant fluid should significantly expand the versatility of the PEM fuel cells in both mobile and stationary applications by offering the advantages of freeze protection, corrosion inhibition, and low electrical conductivity in a single aqueous-based fluid, attributes that are not available in competitive alternates. The commercial applications include, but are not limited to, automotive fuel cell engines, power generation for residential and commercial buildings, back-up power for hospitals and other emergency establishments, fuel cells used in ships and space vehicles, and mobile machinery and equipment

Fuel cells are an efficient, combustion-less, virtually pollution-free source of power. In particular, Proton Exchange Membrane (PEM) fuel cells are ideal for a number of applications, due to their “quick” warm-up characteristics. However, these fuel cells contain some inherent inefficiencies, which results in waste heat that must be removed rapidly via a coolant – currently, either Deionized (DI) water or glycol/water solutions with a DI canister. Although these coolants are non-flammable and thermally efficient, their electrical conductivity increases rapidly unless the DI canister is replaced frequently, which significantly increases capital and maintenance costs. This problem will be addressed by developing a novel Complex Coolant Fluid (CCF), comprised of a base composition and an additive package. The base composition addresses the non-flammability, thermal efficiency, freeze point, and materials compatibility issues, whereas the additive package maintains a low electrical conductivity in the CCF. In Phase I, key ingredients of the proposed additive package were prepared and incorporated into the coolant fluid. The resultant complex coolant fluid formulations were tested in two dynamic loops, and the additives were shown to maintain the electrical conductivity of the coolant below 2.0 microSiemens/cm for more than 325 hours. In Phase II, the additive package will be optimized and a more detailed study of the coolant performance and longevity will be carried out in a dynamic test loop that simulates fuel cell conditions. Optimized coolant samples will tested and validated in actual fuel cells under various operating conditions.

Commercial Applications and Other Benefits as described by the awardee:
The new complex coolant fluid should significantly expand the versatility of the PEM fuel cells in both mobile and stationary applications by offering the advantages of freeze protection, corrosion inhibition, and low electrical conductivity in a single aqueous-based fluid, attributes that are not available in competitive alternates. The commercial applications include, but are not limited to, automotive fuel cell engines, power generation for residential and commercial buildings, back-up power for hospitals and other emergency establishments, fuel cells used in ships and space vehicles, and mobile machinery and equipment.