| This project successfully demonstrated the use of a proton-exchange membrane (PEM) fuel cell as the hydrogen utilization device in the StarFuel System. This unique system uses the unsteady power from the sun, through use of a photovoltaic array to supply electrical energy to a bank of solid polymer electrolyte (SPE{dollar}spcircler{dollar}) electrolyzers. The hydrogen generated is then stored as a solid metal hydride. As of the end of 1996, although the solar-powered generation of hydrogen and the storage of that hydrogen as a hydride had been demonstrated, the connection from the hydride storage to the fuel cell had not yet been made. However, on April 2, 1997, the hydride tanks were first used successfully to supply hydrogen to the fuel cell, thus completing the concept of the StarFuel System.; In addition, the ability to successfully complete a switchover from one discharging hydride tank to another without causing a fluctuation in the power output from the fuel cell to the load was demonstrated. This was accomplished on April 10, 1997 during the first completely integrated system test yet conducted on the StarFuel System.; Finally, additional work accomplished on the system included the upgrading of the purification system, which filters the hydrogen generated by the electrolyzers in preparation for storage in the metal hydride units. Also, an inert gas, ultra-high purity nitrogen, was incorporated into the purging procedures for both the electrolyzer and hydrogen utilization modules. |
