> Recent advances in multistage solar distillation are promising for the sustainable supply of freshwater. However, significant performance degradation due to salt accumulation has posed a challenge for both long-term reliability of solar desalination and efficient treatment of hypersaline discharge. Here, inspired by a natural phenomenon, thermohaline convection, we demonstrate a solar-powered multistage membrane distillation with extreme salt-resisting performance. Using a confined saline layer as an evaporator, we initiate strong thermohaline convection to mitigate salt accumulation and enhance heat transfer. With a ten-stage device, we achieve record-high solar-to-water efficiencies of 322%–121% in the salinity range of 0–20 wt % under one-sun illumination. More importantly, we demonstrate an extreme resistance to salt accumulation with 180-h continuous desalination of 20 wt % concentrated seawater. With high freshwater production and extreme salt endurance, our device significantly reduces the water production cost, paving a pathway toward the practical adoption of passive solar desalination for sustainable water economy.
> Sustainable Development Goal 6 (SDG 6 or Global Goal 6) declares the importance of achieving "clean water and sanitation for all". It is one of the 17 Sustainable Development Goals established by the United Nations General Assembly to succeed the former Millennium Development Goals (MDGs).
> They assert that if the system is scaled up to the size of a small suitcase, it could produce about 4 to 6 liters (1 to 1.5 gallons) of drinking water per hour and last several years before requiring replacement parts. At that scale and performance, the system could produce drinking water at a rate and price that’s cheaper than tap water.
> A scaled-up device could passively produce enough drinking water to meet the daily requirements of a small family. It could also supply off-grid coastal communities near seawater.
"140-year-old ocean heat tech could supply islands with limitless energy" if there's a 20° C thermal gradient; because the ocean is a big thermal battery that stores infrared from the sun especially at the surface of the water:
https://news.ycombinator.com/item?id=38222695
"Extreme salt-resisting multistage solar distillation with thermohaline convection" (2023) https://www.cell.com/joule/abstract/S2542-4351(23)00360-4 :
> Recent advances in multistage solar distillation are promising for the sustainable supply of freshwater. However, significant performance degradation due to salt accumulation has posed a challenge for both long-term reliability of solar desalination and efficient treatment of hypersaline discharge. Here, inspired by a natural phenomenon, thermohaline convection, we demonstrate a solar-powered multistage membrane distillation with extreme salt-resisting performance. Using a confined saline layer as an evaporator, we initiate strong thermohaline convection to mitigate salt accumulation and enhance heat transfer. With a ten-stage device, we achieve record-high solar-to-water efficiencies of 322%–121% in the salinity range of 0–20 wt % under one-sun illumination. More importantly, we demonstrate an extreme resistance to salt accumulation with 180-h continuous desalination of 20 wt % concentrated seawater. With high freshwater production and extreme salt endurance, our device significantly reduces the water production cost, paving a pathway toward the practical adoption of passive solar desalination for sustainable water economy.
- "Desalination system could produce freshwater that is cheaper than tap water" (2023) https://news.ycombinator.com/item?id=37681004 https://news.mit.edu/2023/desalination-system-could-produce-...
Distilled water: https://en.wikipedia.org/wiki/Distilled_water
Distillation > Desalination by distillation: https://en.wikipedia.org/wiki/Distillation#Desalination_by_d...
Desalination: https://en.wikipedia.org/wiki/Desalination
Salinity > See also: https://en.wikipedia.org/wiki/Salinity#See_also
TDS: Total Dissolved Solids sensor: https://en.wikipedia.org/wiki/Total_dissolved_solids#Measure...
Thermohaline circulation: https://en.wikipedia.org/wiki/Thermohaline_circulation
https://en.wikipedia.org/wiki/Sustainable_Development_Goal_6 :
> Sustainable Development Goal 6 (SDG 6 or Global Goal 6) declares the importance of achieving "clean water and sanitation for all". It is one of the 17 Sustainable Development Goals established by the United Nations General Assembly to succeed the former Millennium Development Goals (MDGs).
https://electrek.co/2023/10/02/mit-solar-power-drinking-wate... :
> They assert that if the system is scaled up to the size of a small suitcase, it could produce about 4 to 6 liters (1 to 1.5 gallons) of drinking water per hour and last several years before requiring replacement parts. At that scale and performance, the system could produce drinking water at a rate and price that’s cheaper than tap water.
> A scaled-up device could passively produce enough drinking water to meet the daily requirements of a small family. It could also supply off-grid coastal communities near seawater.
"140-year-old ocean heat tech could supply islands with limitless energy" if there's a 20° C thermal gradient; because the ocean is a big thermal battery that stores infrared from the sun especially at the surface of the water: https://news.ycombinator.com/item?id=38222695