Demonstration test of gas contaminants adsorbent for space Stirling cooler

• Published in: Cryogenics (Guildford) 2024-07, Vol.141, p.103884, Article 103884
• Main Authors: Sato, Yoichi, Tanaka, Kosuke, Shinozaki, Keisuke
• Format: Article
• Language: English
• Subjects: Adsorbent; Gas contaminants; Space application; Stirling cooler
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/j.cryogenics.2024.103884

•Demonstration of gas contamination adsorbent applied to space Stirling cooler for long life.•Reduction of doped CO2 of 4990 ppm to allowable limit of 500 ppm by operating the cooler’s compressor for gas transportation to adsorbent.•Recovering from degraded cooling performance to a comparable level of below 20 K achieved by high-purity helium. A Stirling cooler for space use must have a 5–10 year service life. The primary limitation is the degradation of cooling performance by gas contaminants, such as H2O, CO, CO2, O2, and N2. If these gas contaminants freeze in the regenerator or the displacer’s clearance seal, they can block the helium flow for heat exchange or disturb the smooth movement of the displacer. This study verified the effect of adsorbent adapted for the 20 K-class two-stage Stirling (2ST) cooler with a correlation between the cooling performance and the residual concentration of CO2 gas contaminant. Although the 2ST cooler was stopped by a displacer stuck during initial cooling by adding CO2 at 4990 ppm, the cooling performance was finally recovered to a reference level below 20 K when the equipped adsorbent was activated. Gas analysis showed that the residual CO2 concentration was successfully reduced to 426 ppm, satisfying the less than 500 ppm requirement.