Theoretical and experimental study of a 10 kilowatt proton exchange membrane fuel cell's thermal and moisture system control: Master's thesis

A fuel cell is an electrochemical device that converts fuel and oxidant into electricity. Fuel cells are considered a promising future energy technology, due to their potential for efficient and environmental energy production.

In this thesis a middle pressure, 10 kW scale electrical power proton exchange membrane (PEM) fuel cell system has been studied, concentrating on air and moisture management. The issue of whether a small pressurization could benefit the PEMFC system has been examined. Since the examination is targeted to a real system that could be built of serial production components, system component availability has also been mapped. It was noted that there are no commercial compressors for the PEMFC systems in this power range.

Pressurization is known to have many advantages over non pressurized fuel cell systems, namely pressurization makes the system smaller and lighter and therefore cheaper. Pressurization also eases water management, since at higher pressures less water is needed to reach the same relative humidity levels. However, the high pressure systems are more complex and costly to build because of required special equipment. In this work, middle pressure denotes the pressures between atmospheric and 1.5 bar.

In this study net power gain was not achieved, mainly because of blowers in this range have fairly low efficiencies and best efficiency area is typically narrow.
The power density increases by pressurization and this leads system size and cost reductions.