Development of a Water Cryocooler System for use in the Dehumidification of a Spacecraft Cabin Atmosphere



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48th International Conference on Environmental Systems


The HYbrid Dehumidification and Reclamation Apparatus (HYDRA) project is part of NASA’s eXploration Habitat (X-HAB) program to develop technologies for future long-duration human space missions. Current atmosphere revitalization technologies require frequent serious maintenance and spare parts, which may pose unacceptable risk to future proposed missions to Mars and beyond. Cryogenic CO2 removal has been proposed as a new method for atmosphere revitalization by a team at NASA Ames Research Center. This process involves cooling a stream of cabin air to a temperature low enough to freeze out CO2 as dry ice. For this reason, it is important that the cabin air stream be sufficiently dried to avoid water condensation and ice formation in the cryogenic CO2 removal system – the humidity removal being the focus of the HYDRA project. HYDRA will design, build, and test a dehumidification system for drying the cabin air stream. Two methods are currently under design: one uses a gas-liquid membrane contactor, and the second cryogenically freezes out water from the air stream. In the first, the cabin air stream is sent through a membrane contactor in which a hygroscopic ionic liquid (IL) adsorbs the water vapor from the cabin air stream. The IL is then heated at reduced pressure to desorb water vapor and recover for reuse. The water vapor cryo cooler employs a swing-bed system which cycles between a cooling phase, where a cryo cooler cools the cabin air freezing out water vapor as ice, and a warming phase, where the ice is melted and removed from the system. Results of laboratory experiments to characterize the performance of such a dehumidification system are presented and assessed for feasibility to operate with a cryogenic CO2 removal system.


Trevor Fritz, University of Colorado - Boulder
James Nabity, University of Colorado - Boulder
ICES302: Physio-chemical Life Support- Air Revitalization Systems -Technology and Process Development
The 48th International Conference on Environmental Systems was held in Albuquerque, New Mexico, USA on 08 July 2018 through 12 July 2018.


Ionic liquid, Cryogenic, CO2 removal dehumidification, humidity, Deep Space, Air Revitatlization