Development of Water Electrolysis System for Oxygen Production Aimed at Energy Saving and High Safety

Date

2015-07-12

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Publisher

45th International Conference on Environmental Systems

Abstract

The Japan Aerospace Exploration Agency (JAXA) has been studying and developing Environmental Control and Life Support System (ECLSS) technologies, in particular an air regeneration system to support long-duration manned space missions beyond Earth orbit. Our goal is to develop an air regeneration system that is lightweight, compact and energy efficient. The air regeneration system comprises a water electrolysis subsystem for O2 generation, a CO2 removal subsystem and a CO2 reduction subsystem. In this paper, we report on improvements to the water electrolysis subsystem. The water electrolysis cell uses a solid polymer electrolyte (SPE) developed by JAXA and a water/gas separator to separate generated H2 from circulated water using a membrane. A previous design of the water electrolysis system had a number of issues. One was an increasing concentration of H2 in the generated O2 gas due to the low temperature of the circulated water. To address this issue, we improved the catalyst of the membrane electrode assembly (MEA) and as a result, low hydrogen concentrations were maintained at all temperatures. A further issue was a large pressure drop through the water/gas separator. By creating a stack of four separators and improving the internal flow path, the pressure drop was reduced to approximately one third of that of the previous design, and it became possible to circulate water at a high flow rate.

Description

Bellevue, Washington
Masato Sakurai, Japan Aerospace Exploration Agency, Japan
Takuma Terao, Japan Aerospace Exploration Agency, Japan
Yoshitsugu Sone, Japan Aerospace Exploration Agency, Japan
The 45th International Conference on Environmental Systems was held in Bellevue, Washington, USA on 12 July 2015 through 16 July 2015.

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