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Patent-pending Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is currently being investigated for removal and rejection of carbon dioxide (CO2) and heat from a Portable Life Support System (PLSS) to a Martian environment. The metabolically-produced CO2 present in the ventilation loop gas is collected using a CO2 selective adsorbent that has been cooled via a heat exchanger to near CO2 sublimation temperatures (∼195 K) with liquid CO2 (LCO2) obtained from Martian resources. Once the adsorbent is fully loaded, used, warm (∼300 K), moist ventilation loop gas is used to heat the adsorbent via another heat exchanger to reject the collected CO2 to the Martian ambient. Two beds are used to achieve continuous CO2 removal by cycling between the cold and warm conditions for adsorbent loading and regeneration, respectively.

Metabolic heat regenerated temperature swing adsorption (MTSA) technology is being developed for removal and rejection of carbon dioxide (CO2) and heat from a portable life support system (PLSS) to the Martian environment. Previously, hardware was built and tested to demonstrate using heat from simulated, dry ventilation loop gas to affect the temperature swing required to regenerate an adsorbent used for CO2 removal. New testing has been performed using a moist, simulated ventilation loop gas to demonstrate the effects of water condensing and freezing in the heat exchanger during adsorbent regeneration. Also, the impact of MTSA on PLSS design was evaluated by performing thermal balances assuming a specific PLSS architecture. Results using NASA's Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT), a PLSS system evaluation tool, are presented.

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. CO2 removal and rejection is accomplished by driving a sorbent through a temperature swing starting at below freezing temperatures. The swing is completed by warming the sorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. Designing a heat exchanger to efficiently transfer this energy to the sorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210 K to 280 K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously.