Amine Swingbed (Amine Swingbed) - 08.05.14
ISS Science for Everyone
Science Objectives for Everyone
The Amine Swingbed experiment uses an amine-based chemical combined with the vacuum of space to filter and renew cabin air for breathing. Removing carbon dioxide and moisture from consumed air using this system reduces the demand to supply new air. Amine-based air filtering systems are now being tested for their efficiency and reliability on long-duration space missions.
Science Results for Everyone
Johnson Space Center, Crew and Thermal Systems Division, Houston, TX, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Technology Demonstration Office (TDO)
ISS Expedition Duration
March 2011 - September 2014
Previous ISS Missions
This is the first test of the Amine Swingbed payload. A similar technology (amine based pressure swing adsorption) was used on the shuttle extended duration orbiter, in the form of the Regenerative Carbon Dioxide Removal System (RCRS). The Amine Swingbed payload uses an amine with a significantly greater capacity for CO2 than the RCRS.
- Vacuum Regenerated Amine Systems have traditionally been applied to relatively short duration human space flight missions. Water vapor is removed along with the CO2 - this benefits short duration missions by simplifying process hardware, but long duration missions that seek to recover, purify and recycle water have not considered vacuum amine systems for CO2 recovery.
- This payload integrates a desiccant wheel-based water recovery device with a vacuum amine system. This combined system uses less power (because space vacuum is used to regenerate the amine bed instead of heaters) and it is smaller in size (because it can cycle frequently).
- The primary research objective is to assess the prospect for sustainable operations in a flight environment using a water recovery/vacuum regeneration approach. Supporting research objectives are to measure the effectiveness of the CO2 removal system across a wide range of operating conditions, and to measure the performance of two technologies necessary for long term capability: water recovery and ullage (unfilled space) air recovery.
There are three classes of research objectives.
Primary Research Objective:
- To assess sustainable performance of a vacuum amine swingbed in a flight environment. Environmental Control and Life Support Systems frequently function well in the lab, but suffer degraded performance or subsystem failure in a flight environment. These systems are sometimes attributed to microgravity, but more frequently are caused by the multifaceted nature of the flight environment that is impossible to re-create in the lab. The primary objective of this payload is to ascertain whether or not the flight environment will affect system performance.
Supporting Research Objectives:
Detailed Performance Metrics:
- Determine the effect of flight vacuum systems on CO2 removal performance.
- Determine the effect of CO2 concentration on system removal efficiency.
- Determine the effect of process air speed on system removal efficiency.
System Aspects of Payload Hardware:
- Measure the performance of a desiccant wheel based water recovery system.
- Measure the performance of a tank transfer air save system.
- Measure the effectiveness of acoustic treatments of payload equipment.
Space missions need a way to remove the carbon dioxide (CO2) exhaled by crewmembers. The Amine Swingbed experiment draws cabin air through a dehydration wheel to remove excess moisture. The device contains two amine beds, which capture and trap CO2. Once the CO2 is removed, the system returns the treated air to the ISS cabin. The experiment tests how well the equipment performs in space.
Vacuum-based amine recovery systems are more useful in space than on Earth because the readily available vacuum of space simplifies the process of regenerating the amine. But the systems could also remove carbon dioxide and humidity in tight enclosures on Earth, for instance in mine tunnels or underwater vessels, if there is an efficient way to purge the amine.
Once the experimental hardware is configured, the crew is not needed to operate the system. Because the payload is a full scale system, capable of six crew equivalent CO2 removal, the mass flow of CO2 out the ISS vacuum vent is relatively large compared to other payloads. This payload needs dedicated access to the ExPRESS rack vacuum jumper. Because this is a CO2 removal experiment, this payload needs exposure to ISS cabin air.
After the crew configures the hardware and connects the payload to the ISS vacuum system, the payload can operate from ground controls. Cabin air is drawn through the payload system: first the air is drawn through the desiccant wheel which removes humidity from the air, then the CO2 laden (but dry) cabin air is exposed to the amine swingbed. CO2 is adsorbed, and dry, CO2 free air is drawn through the regeneration section of the desiccant wheel. The water is stripped from the desiccant wheel, and returned to the cabin (in the form of warm, humid air that is free from CO2). To assess system sustainability, the payload requests 1000 hours of operation time. This time can be segmented. An ideal segment would be two days of continuous operation. Because of startup effects, test durations lasting less than four hours can test hardware reliability, but not CO2 removal performance.
Ground Based Results Publications
Amine Swingbed unit.
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NASA Image: ISS030E010406 - View of valve motor position sensor on the Amine Swingbed Hardware during Assembly in the U.S. Laboratory. Photo was taken during Expedition 30.
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NASA Image: ISS030e010420 - Dan Burbank,Expedition 30 Commander,during Amine Swingbed Hardware Assembly in the U.S. Laboratory.
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