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by westurner 5 days ago
ScholarlyArticle: "Extreme salt-resisting multistage solar distillation with thermohaline convection" (2023) https://www.cell.com/joule/fulltext/S2542-4351(23)00360-4 .. https://scholar.google.com/scholar?cites=7551078272963689346...

"Desalination system could produce freshwater that is cheaper than tap water" (2023) https://www.eurekalert.org/news-releases/1002811

ScholarlyArticle: "Highly efficient and salt rejecting solar evaporation via a wick-free confined water layer" (2022) https://www.nature.com/articles/s41467-022-28457-8

"Solar-powered system offers a route to inexpensive desalination" (2022) https://news.mit.edu/2022/solar-desalination-system-inexpens...

1 comments

I remember the MIT press release. I wonder if they've found any commercial success.
MIT had a spin-out company some years ago doing HDH (Humidification-Dehumidification) desalination.

In thermal cycles, the problem has been in the condensation step. If there is a carrier gas present this inhibits heat/mass transfer at the condenser surfaces. The usual way of getting around this has been to operate the system with no carrier gas, but that requires pressures below atmospheric pressure, requiring strong walls to withstand external atmospheric pressure.

The MIT invention was a bubble tray contactor, where air is bubbled up through trays of progressively cooler water. The water/air bubble interface provides a large surface area at low cost. One of the markets for this was cleaning up brine from fracked wells.

The company, Gradiant, is still around but has evolved to involve a wider range of water treatment technologies (which is very sensible from a business viewpoint, as customers buy complete solutions, not individual technologies). https://www.gradiant.com/