Microsoft patents freezing carbon dioxide out of the air
This filing describes a system that cools air until carbon dioxide turns into a solid, allowing it to be scraped off and stored while the rest of the air is released. The process uses a heat exchanger to pre-cool the air and a cryogenic refrigerator to keep the collection surface below the freezing point of CO2.
In the filing’s own words
Cryogenic removal of carbon dioxide from the atmosphere, or CryoDAC (Cryogenic Direct Air Capture), uses extremely low temperatures to convert atmospheric CO 2 into a frozen solid while other components of air such as oxygen and nitrogen remain as gases. Air from the atmosphere is passed through a recuperative heat exchanger to cool the air to a temperature slightly above the deposition point of CO 2. The cooled air is then passed over a deposition surface chilled to a temperature below the deposition point of CO 2. Carbon dioxide in the air transitions from gas to solid form upon contact with the deposition surface. The frozen CO 2 is collected and stored. The cold air with CO 2 removed is passed back through the recuperative heat exchanger to cool incoming air and is then returned to the atmosphere. The deposition surface may be cooled by a cryogenic refrigerator.
What exactly they claim (claim 1)
1. A system for removal of atmospheric carbon dioxide (CO 2) comprising: (a) a fan configured to inject air from the atmosphere into the system; (b) a recuperative heat exchanger configured to receive the air from the fan and cool the air to a first temperature above a deposition point of atmospheric CO 2; (c) a deposition chamber configured to receive the cooled air from the recuperative heat exchanger and contact the cooled air with a deposition surface chilled to a second temperature below the deposition point of atmospheric CO 2 to cause formation of solid CO 2 and removal of CO 2 from the air; (d) a return pathway from the deposition chamber that passes through the recuperative heat exchanger where the air from the deposition chamber cools the air injected from the atmosphere and returns the air to the atmosphere with at least some of the CO 2 removed; (e) a cryogenic refrigerator thermally coupled to the deposition surface and configured to remove heat from the deposition surface to maintain the second temperature below the deposition point of atmospheric CO 2; (f) means for removing the solid CO 2 from the deposition surface; (g) at least one temperature sensor configured to detect a temperature of air within the system; and (h) control circuitry configured to adjust at least one of (i) a speed of the fan to maintain a temperature of the cooled air leaving the recuperative heat exchanger at the first temperature or (ii) a temperature of the deposition surface to maintain a temperature of the cooled air leaving the deposition chamber at the second temperature, the control circuitry further configured such that CO 2 is removed from the air.
Facts
- Company
- Microsoft (MICROSOFT TECHNOLOGY LICENSING, LLC)
- Official title
- CRYOGENIC REMOVAL OF CARBON DIOXIDE FROM THE ATMOSPHERE
- Publication number
- US20260276301A1
- Application number
- 19666119
- Filed
- May 1, 2026
- Published
- Sep 17, 2026
- Inventors
- 3
- Claims
- 20
Classified under
F25J 3/067 Mechanical engineeringF25J 2210/40 Mechanical engineeringF25J 2215/80 Mechanical engineeringMore from Microsoft in Batteries & energy
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Summaries are simplified from the filing’s own abstract and first claim. A patent filing is not a product announcement.
Patent data and drawings: U.S. Patent and Trademark Office (USPTO). Nebula is not affiliated with or endorsed by the USPTO.