Browsing by Author "Palmer, Gary H."
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Item Development and Testing of a Two-Stage Air Drying System for Spacecraft Cabin CO2 Removal Systems(44th International Conference on Environmental Systems, 2014-07-13) Hogan, John; Jan, Darrell; Palmer, Gary H.; Richardson, Tra-My Justine; Linggi, Paul; Lu, Zhe; Kamiya, TakeshiThe use of molecular sieves such as zeolite for the removal of CO2 in spacecraft cabin atmospheres necessitates thorough water removal prior to processing. This is because water also binds readily with these sieves, and will lead to reduced CO2 loading capacity and water-contaminated CO2 streams for resource recovery. A two-stage air drying system has been under development at NASA Ames Research Center to address this need. The system consists of a membrane-based bulk dryer designed to passively remove up to 80% of the inlet water using the ultra-dry exhaust airstream from the CO2 removal system, and a regenerable, thermal-swing, structured-sorbent residual dryer that removes the remaining water to a nominal exit dew-point of -65oC. Individual unit testing of both of these units was conducted and indicates both are potential candidates for use in future missions. This paper provides that data from these tests.Item Performance of Silica Gel in the Role of Residual Air Drying(44th International Conference on Environmental Systems, 2014-07-13) Jan, Darrell; Hogan, John; Koss, Brian; Palmer, Gary H.; Richardson, Tra-My Justine; Knox, James; Linggi, PaulRemoval of carbon dioxide (CO2) is a necessary step in air revitalization and is often accomplished with sorbent materials. Since moisture competes with CO2 in zeolite sorbent materials, it is necessary to remove the water first. This is typically accomplished in two stages: “bulk” removal and “residual” drying. Silica gel is used as the bulk drying material in the Carbon Dioxide Removal Assembly (CDRA) in operation on ISS. There has been some speculation that silica gel may also be capable of serving as the residual drying material. This paper describes test apparatus and procedures for determining the performance of silica gel in residual air drying.