VCHP Heat Exchanger for Passive Thermal Management of a Fuel Cell Reforming Process

The subject of this proposal is a heat exchanger based on variable conductance heat pipes (VCHP) that will provide a passive, valve-less means of regulating process gas temperatures in reformers for fuel cells. A key component of the Navy fuel cell system is the reformer, which converts diesel fuel into methane for consumption by the fuel cell. Reaction temperatures are critical to proper function of the reformer. Reaction temperatures are currently regulated by valves in the process gas streams. These valves require power, consumes space, increases pressure drop, and is hindering tight integration and packaging of the reformer. In addition, these valves are prone to failure at elevated temperatures. The VCHP-based system has the potential to provide nearly constant reformer temperatures despite wide changes in gas flow rate while needing no additional components or control systems and without limiting packaging options for the reformer.