At last spring’s National Hydrogen Association (NHA) conference, graduate research assistant Andrea Allen reported on the performance and efficiency of our hydrogen fueling station over its first full year of operation. During the conference, SERC director Peter Lehman and Andrea discussed the efficiency of the electrolyzer with representatives from Proton Energy Systems, the unit’s manufacturer. With the desire to field test their new product, Proton offered to replace the current electrolyzer cell stack with a newer developmental model, designed for higher efficiency and lower cost. This new cell stack uses a bipolar plate design with a 70% part count reduction. Fewer parts result in an overall reduction in the interfacial resistances of the cell stack, which leads to better performance. In addition to replacing the electrolyzer cell stack, Proton recommended installing a valve to partially bypass the heat exchanger, allowing the electrolyzer to run at a higher temperature, which further increases the efficiency.
To test the performance and quantify the improved efficiency of the new cell stack, SERC senior research engineer, Greg Chapman first installed the heat exchanger bypass and we monitored the energy use of the original electrolyzer cell stack at normal operating temperatures and at elevated temperatures, as benchmarks of performance. The new cell stack was then installed and we collected similar data at the same temperatures. The testing definitively shows that the new cell stack uses the same current to produce hydrogen at a similar rate as the original cell stack, but operates at a lower voltage. This decrease in voltage results in a lower power draw and an approximately 8% increase in electrolyzer efficiency. Additionally and not surprisingly, we found that the efficiency of the electrolyzer increases substantially at higher operating temperatures. We will present the data from these tests of the original and new cell stacks’ performance at this year’s NHA conference from May 3rd – 5th in Long Beach, California.