CO2-Based Closed-Loop Cleaning System for Microgravity Environments
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Solution Overview
Problem
Current space exploration missions face challenges in cleaning dirty clothing due to the lack of effective systems for low-, micro-, and zero-gravity environments, leading to high logistical and financial costs and waste generation, as conventional cleaning systems rely on water and Earth-based gravity.
Innovation Solution
Carbon dioxide-based cleaning systems that operate in closed-loop or open-loop configurations, utilizing liquid CO2 for cleaning clothes in microgravity environments, with components like a holding tank, rotary cleaner, compressor, and condenser to recycle and reuse CO2, and optional distillation tanks for contaminant separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional water-based cleaning systems are used in space, then cleaning effectiveness is maintained, but system complexity and resource requirements increase significantly
Solution Approach 1:
The patent extracts water from the cleaning system entirely, replacing it with carbon dioxide as the cleaning agent. This eliminates the need for water storage, water pumping systems, and water drainage infrastructure, significantly simplifying the overall system while maintaining cleaning effectiveness through CO2's unique properties as a solvent and cleaning fluid
Solution Approach 2:
The patent changes the physical state and properties of the cleaning agent from liquid water to carbon dioxide in various phases (liquid, gas, supercritical). By controlling temperature and pressure parameters, the system utilizes CO2's phase transitions to achieve cleaning, drying, and sanitizing functions that traditionally required water-based systems
2Ease of operation
If water-based cleaning systems are used in space, then cleaning function is provided, but resource consumption and waste generation increase
Solution Approach 1:
The patent implements a closed-loop system where carbon dioxide is continuously recovered and recycled. The CO2 that evaporates during cleaning, along with any contaminants, is captured, filtered, and re-condensed back into liquid CO2 for reuse. This eliminates the need for continuous water resupply and prevents waste generation, as the same CO2 is reused throughout the mission duration
Solution Approach 2:
The system uses carbon dioxide that can be obtained from crew respiration and metabolic processes, turning a waste product into a valuable cleaning resource. The CO2 recovery system automatically captures and recycles gas without requiring external water supplies, making the system self-sufficient throughout the mission
3Reliability
If clothing is discarded after use in space, then hygiene is maintained, but launch mass and storage requirements increase
Solution Approach 1:
The patent enables continuous cleaning of clothing throughout the mission duration through repeated cleaning cycles using the same CO2 supply. The system can clean multiple garments sequentially or simultaneously, extending the usable life of clothing from single-use to multiple-use, thereby reducing the total amount of clothing that must be launched and stored
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables cost-effective and waste-reducing clothing cleaning in space by reusing CO2, extending clothing life, and reducing the need for resupply, while operating without water and at ambient temperatures.
Implementation Method 1
a compressor arranged to receive gaseous CO2 and increase a pressure of the gaseous CO2
Implementation Method 2
a condenser arranged to receive the increased pressure gaseous CO2 from the compressor and convert the gaseous CO2 into liquid CO2
Implementation Method 3
the internal drum is porous to liquid CO2 and contaminants carried by the liquid CO2 but prevents clothing from passing out of the internal drum
Data Source
AI summary
Carbon dioxide-based cleaning systems include a holding tank containing a supply of liquid carbon dioxide (CO2), a rotary cleaner having an internal drum arranged therein, the rotary cleaner fluidly coupled to the holding tank to receive liquid CO2 therefrom, the rotary cleaner configured to output CO2 with contaminants after a cleaning cycle, a compressor arranged to receive gaseous CO2 and increase a pressure of the gaseous CO2, and a condenser arranged to receive the increased pressure gaseous CO2 from the compressor and convert the gaseous CO2 into liquid CO2 and direct the liquid CO2 into the holding tank.