High Pressure, In-Situ Hydrogen Sensor For Space Based Regenerative Fuel Cell Systems

Makel Engineering Inc. (MEI) will develop a miniaturized, in-situ, stable, long-life hydrogen sensor for use in high pressure oxygen process streams within regenerative fuel cell systems. The hydrogen sensor will be able to be used directly in oxygen streams operating up to 3600 psia to monitor trace hydrogen which can pose a safety issue. MEI will adapt a miniaturized hydrogen sensor technology that has been successfully used for safety monitoring of low pressure oxygen generators, fuel cells, and for launch vehicle leak detection applications. This program will innovate on this demonstrated hydrogen microsensor technology with application specific design modifications and packaging required to meet the unique challenges of the space based regenerative fuel cell systems including tolerance to condensed water vapor, high pressure, low power and mass, and long calibration life without servicing or replacement. The sensor will be designed to easily integrated and embedded in systems with interfaces similar to small pressure and temperature transducers. The technology is based on MEMs based Pd/alloy hydrogen detection elements on silicon with operational capability up to 100% hydrogen. The technology has recently been extended to higher temperature and pressure applications. The sensing element design (resistive and diode) elements are formed with thin film fabrication processes and the Pd/alloy composition has been demonstrated to be highly specific to hydrogen. able to operate with or without oxygen in the background, and insensitivity to common process stream contaminates such as carbon monoxide and hydrocarbons. Phase I will demonstrate and test a prototype sensors which can detect hydrogen in the 0 to 4% range with high accuracy at pressures up to 3600 psia with saturated oxygen.