Packaging and testing of a hydrogen safety sensor prototype

In this article, testing of an electrochemical, potentiometric hydrogen safety sensor is reported within a proposed packaging scheme. Device packaging under static and flow testing conditions are presented. During the static volume sensor testing, the sensors response is compared against a calibrated Gas Chromatography (GC) measurement. Also, a commercial H-2 sensor is incorporated into the test chamber to act as a benchmark for the sensor prototype. In the testing phase, H-2 selectivity is demonstrated using pulsed discharge technique. The packaging schemes for static and flow condition testing permit easy handling and exchange of the laboratory prototype sensors with other agencies for independent testing/performance validation. Upon testing, for a fixed inlet concentration of 2%2(20,000 pp.m) H-2 and within the duration of the typical experiment conducted within a non-sealed test chamber, the sensor sees only around 6200 ppm as confirmed by the GC measurements. The sensitivity is around 105 mV for 6200 ppm of H-2. While a logarithmic correlation of the sensor output with H-2 concentration is observed in laboratory based H-2 sensor, the commercial device suffered from an elevated baseline (due to reduced barometric pressure conditions of 2195 m elevation), humidity and uncorrelated sensor output for different H-2 concentrations. The pulsed discharge scheme for achieving hydrogen selectivity holds a great potential for tackling cross-sensitivity problems that affect many H-2 sensor technologies. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.