One commercial application is VCHP heat exchangers in fuel cell reformers. In a fuel cell reformer, diesel fuel and air pass through a series of high temperature reactors to generate hydrogen. The operating temperature of the reactors must be closely controlled to maintain their chemical equilibrium. The current scheme uses a bypass valve, which has several drawbacks: it requires active control, requires power, and has a large pressure drop. A VCHP heat exchanger can replace the current heat exchanger and control system with a passive system that automatically maintains the output stream from the heat exchanger at a constant temperature.
The immediate application is for a long-lived Venus lander that contains a Stirling system integrated with a large number of GPHS modules. The thermal management system will efficiently collect the heat from the GPHS modules and deliver it to the Stirling engine. The thermal management system will allow the Stirling convertors to be shutoff during the transit to Venus. More generally, the systems developed on this program are applicable to all NASA missions with high powered radioisotope systems that require a large number of GPHS modules. Beside the Venus mission applications, the technology is applicable to lunar missions for both long (habitation modules) and short duration (International Lunar Network).