Desalination system could produce freshwater that is cheaper than tap water

MIT News ^ | September 27, 2023 | Jennifer Chu

[SunkenCiv]

The team's new system improves on their previous design — a similar concept of multiple layers, called stages. Each stage contained an evaporator and a condenser that used heat from the sun to passively separate salt from incoming water. That design, which the team tested on the roof of an MIT building, efficiently converted the sun's energy to evaporate water, which was then condensed into drinkable water. But the salt that was left over quickly accumulated as crystals that clogged the system after a few days. In a real-world setting, a user would have to place stages on a frequent basis, which would significantly increase the system's overall cost.

In a follow-up effort, they devised a solution with a similar layered configuration, this time with an added feature that helped to circulate the incoming water as well as any leftover salt. While this design prevented salt from settling and accumulating on the device, it desalinated water at a relatively low rate.

In the latest iteration, the team believes it has landed on a design that achieves both a high water-production rate, and high salt rejection, meaning that the system can quickly and reliably produce drinking water for an extended period. The key to their new design is a combination of their two previous concepts: a multistage system of evaporators and condensers, that is also configured to boost the circulation of water — and salt — within each stage.

[SunkenCiv]

A tilted ten-stage prototype is located into a "boat-like" reservoir.

Credit: Jintong Gao and Zhenyuan Xu

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Outdoor test of the prototype under natural sunlight.

Credit: Jintong Gao and Zhenyuan Xu

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[SunkenCiv]

The rest of the desalination keyword, sorted:

• Water-starved Saudi confronts desalination's heavy toll [09/17/2023]
• Instead of building enough desalination plants, California is trying to solve its water shortage by removing the racism from water [01/16/2023]
• Arizona might hire Israel to help build a desalination plant [12/28/2022]
• Newsom pushes desalination, rain capture, cutting red tape, as California dries out [08/12/2022]
• After Nixing 50-Million-Gallon-A-Day Desalination Plant, California Demands Residents Use Less Water [05/30/2022]
• Agency unanimously rejects California desalination project [05/14/2022]
• Developer wants to build $1.4 billion seawater desalination plant in Huntington Beach [CA] [05/11/2022]
• Coastal Panel Staff Advises Against Huntington Beach Desalination Plant (California) [04/30/2022]
• How an AP1000 Plant Is Changing the Nuclear Power Paradigm Through District Heating, Desalination [11/01/2021]
• Is desalination the answer to California's drought? Here's what experts say [08/18/2021]
• High Efficiency at Low Cost: New Catalyst Moves Seawater Desalination, Hydrogen Production Closer to Commercialization [01/29/2021]
• Egypt to construct world’s largest seawater desalination plant [11/20/2017]
• Israeli water desalination unit makes a worldwide hit [07/11/2017]
• Israel Proves the Desalination Era Is Here [08/02/2016]
• First renewable energy-powered desalination plant unveiled [03/12/2016]
• Future of Desalination Industry Innovation May Rest on Conwed’s 3D Printed Feed Spacers [03/10/2016]
• Are These Technologies Water Desalination Game Changers? [03/05/2016]
• North America's largest seawater desalination plant is ahead of schedule [09/03/2015]
• Desalination plants key to Perth water security [07/10/2015]
• Israel Bringing Its Years Of Desalination Experience To California [06/17/2015]

[SunkenCiv]

[subtitled] MIT engineers and collaborators developed a solar-powered device that avoids salt-clogging issues of other designs.

[yldstrk]

Cough cough, uh huh right.

[Red Badger]

they invented a pool?.....................

[redfreedom]

This water would be as cheap to produce as electricity is cheaply produced from windmills and solar panels.

My point is this system may work great in a lab/scientific environment. But to get water to evaporate using the sun will take an awful huge operation to satisfy the needs of a small 50,000 population town.

I have a feeling the cost per gallon of water will exceed that of a conventional reverse osmosis system once all expenses of production are considered.

[Paladin2]

Where does the salt eventually go?

Wintertime road treatment to dissolve ICE engined cars?

[SunkenCiv]

Walmart and Dollar Tree, for examples.

[SunkenCiv]

“Please don’t pee in our pool, we don’t swim in your toilet.” — sign common to backyard pool areas in the 1960s

[rlmorel]

It is shameful we are in this state with water.

Israel is the world leader in desalination. We need it. We should have it.

What we lack is the will to do it.

Our approach to water supply is akin to our energy approach: a shambles and a farce.

[FirstFlaBn]

Multiple references to cost advantages, but no specifics. I automatically dismiss such puffery as being for the sole purpose of getting the next grant.

[Rightwing Conspiratr1]

Too damn slow. Hook it up to a coal plant.

[SunkenCiv]

Israel's got a high per capita of scientists and engineers, also has greater motivation since the muzzies have defoliated every place they've controlled for long periods of time, and of course water is needed for survival and prosperity.

[rlmorel]

All true.

Of course, water is needed for our survival and prosperity too. The way California has handled water resources is shameful, and many other parts of the country are not far behind it.

[msrngtp2002]

Well navy ships have evaporators. The most expensive part of that is the energy required to heat sea water 150 degrees so the salt water will flash to steam which is then condensed. Aircraft carriers have 4-100000 gpd stills. So the evaporative method is proven. Get the energy cost down and it becomes cost effective.

[SunkenCiv]

Cali's primary problem is that it's a single party state, or as the Cali Demagogic Party pols like to call it, a "durable majority".

[Paladin2]

How does it work in the Winter at higher Latitudes?

[rlmorel]

Oh, yeah. I live in a state with just that setup...:(

[HollyB]

Aruba has an incredible desalination system. It’s crazy they had not used this technology here.

[HollyB]

Or elsewhere.