2015 DOE Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Report

Editors' Choice—Field Trials Testing of Mixed Potential Electrochemical Hydrogen Safety Sensors at Commercial California Hydrogen Filling Stations

“…The fact that temperature, pressure, and relative humidity exhibit 24-hr periodicity is reasonable. However, as stated earlier, sensor testing conducted at LLNL and independent validation and verification sensor testing conducted at the Hydrogen Sensor Testing Laboratory at NREL 15,23,25 showed that these changes had very little effect on the mixed potential sensor baseline. Since the response mechanism of mixed potential sensors relies on electrode kinetics, it is well known that the analyte sensitivity is a strong function of temperature but less so for open circuit voltage (e.g.…”

“…For the first experiment, a tin-doped indium oxide (ITO) based mixed potential sensor was selected due to its level of technology maturation driven by six years of DOE-funded development. [11][12][13][14][15][16][17]22,23 The calibration curve measured in the laboratory, prior to station installation shows that the voltage produced by the sensor and heater control/HIB exhibited the expected logarithmic behavior with increasing hydrogen concentration (Figure 2). The fitted equation, shown in Figure 2, was incorporated into the data acquisition software to convert the logged real-time sensor voltage to real-time hydrogen concentration.…”

“…The sensor/control board and wireless transmitter modules were mounted inside a standard, commercial National Electrical Manufacturers Association (NEMA)-8 enclosure large enough to accommodate both components. 15 Two penetrations were made to the field trials NEMA enclosure to permit continuous sampling of the environment through an intake and chimney formed using 2 in outer diameter PVC pipe. The intake situated at the bottom of the enclosure contained an activated charcoal cartridge; the exhaust chimney situated at the top of the enclosure was fitted with a cap to prevent rainwater infiltration.…”

“…This technology has demonstrated low cross-sensitivity and an ultrafast response time. 11,12 The sensor design and deposition method have undergone iterations over the past decade, [13][14][15][16] resulting in the present configuration, which was tested in four rounds of field trials experiments, spanning a two-year period, conducted at hydrogen stations located in Burbank and Chino, CA.…”

Research Needs for the Solid Oxide Electrolyzer (SOEC) with a Proton-Conducting SOEC (H-SOEC) Electrochemical Hydrogen Compressor (EHC) Energy Conversion Network (ECN)

“…MPa by a single-stage mode with a voltage of 0.159 V (each cell), an inlet pressure of 10 MPa and the maximum pressure was expected to reach 140 MPa 15 . An EHC design by Grigoriev and co-workers transferred lower pressure into high output pressure up to 13 MPa with 0.01 N/m3 flow rate 16 .…”