MIT Researchers Build Solar-Powered Low-Cost Drinking Water Desalination System (mit.edu) 54
MIT engineers have built a solar-powered desalination system that "ramps up its desalting process and automatically adjusts to any sudden variation in sunlight, for example by dialing down in response to a passing cloud or revving up as the skies clear."
While traditional reverse osmosis systems typically require steady power levels, "the MIT system requires no extra batteries for energy storage, nor a supplemental power supply, such as from the grid." And their results were pretty impressive: The engineers tested a community-scale prototype on groundwater wells in New Mexico over six months, working in variable weather conditions and water types. The system harnessed on average over 94 percent of the electrical energy generated from the system's solar panels to produce up to 5,000 liters of water per day despite large swings in weather and available sunlight... "Being able to make drinking water with renewables, without requiring battery storage, is a massive grand challenge," says Amos Winter, the Germeshausen Professor of Mechanical Engineering and director of the K. Lisa Yang Global Engineering and Research Center at MIT. "And we've done it."
The system is geared toward desalinating brackish groundwater — a salty source of water that is found in underground reservoirs and is more prevalent than fresh groundwater resources. The researchers see brackish groundwater as a huge untapped source of potential drinking water, particularly as reserves of fresh water are stressed in parts of the world. They envision that the new renewable, battery-free system could provide much-needed drinking water at low costs, especially for inland communities where access to seawater and grid power are limited...
The researchers' report details the new system in a paper appearing in Nature Water. The study's co-authors are Bessette, Winter, and staff engineer Shane Pratt... "Our focus now is on testing, maximizing reliability, and building out a product line that can provide desalinated water using renewables to multiple markets around the world," Pratt adds. The team will be launching a company based on their technology in the coming months.
This research was supported in part by the National Science Foundation, the Julia Burke Foundation, and the MIT Morningside Academy of Design. This work was additionally supported in-kind by Veolia Water Technologies and Solutions and Xylem Goulds.
Thanks to long-time Slashdot reader schwit1 for sharing the news.
While traditional reverse osmosis systems typically require steady power levels, "the MIT system requires no extra batteries for energy storage, nor a supplemental power supply, such as from the grid." And their results were pretty impressive: The engineers tested a community-scale prototype on groundwater wells in New Mexico over six months, working in variable weather conditions and water types. The system harnessed on average over 94 percent of the electrical energy generated from the system's solar panels to produce up to 5,000 liters of water per day despite large swings in weather and available sunlight... "Being able to make drinking water with renewables, without requiring battery storage, is a massive grand challenge," says Amos Winter, the Germeshausen Professor of Mechanical Engineering and director of the K. Lisa Yang Global Engineering and Research Center at MIT. "And we've done it."
The system is geared toward desalinating brackish groundwater — a salty source of water that is found in underground reservoirs and is more prevalent than fresh groundwater resources. The researchers see brackish groundwater as a huge untapped source of potential drinking water, particularly as reserves of fresh water are stressed in parts of the world. They envision that the new renewable, battery-free system could provide much-needed drinking water at low costs, especially for inland communities where access to seawater and grid power are limited...
The researchers' report details the new system in a paper appearing in Nature Water. The study's co-authors are Bessette, Winter, and staff engineer Shane Pratt... "Our focus now is on testing, maximizing reliability, and building out a product line that can provide desalinated water using renewables to multiple markets around the world," Pratt adds. The team will be launching a company based on their technology in the coming months.
This research was supported in part by the National Science Foundation, the Julia Burke Foundation, and the MIT Morningside Academy of Design. This work was additionally supported in-kind by Veolia Water Technologies and Solutions and Xylem Goulds.
Thanks to long-time Slashdot reader schwit1 for sharing the news.
Re: What do they plan on doing with the waste? (Score:2)
Re: What do they plan on doing with the waste? (Score:5, Interesting)
Use the salt for... You know ... Salt production?
There's millions of tonnes of salt produced all over the planet, for varied uses every year.
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Yup, colocating desal plants and salt pans is a viable approach. Problem is with bore water where the residue is not high quality NaCl.
Re: What do they plan on doing with the waste? (Score:2)
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Curacao has enormous fields dedicated to evaporating ocean water to make salt. Maybe ts not exactly waste if the demand is that high.
Re: What do they plan on doing with the waste? (Score:4)
I was wondering how long it would take for the first complaint about the saline run-off. I sure did not expect it to be the first ;)
Salt, in and of itself, is not toxic. The human body uses chemical ions, sodium & chlorine (potassium is another along with magnesium & phosphorus), that can be combined to make a "salt" molecule.
The problem comes down to the volume of waste and what form it will take.
If it is saline waste, perhaps it could be pumped into nearby settling ponds placed on arid unusable land. Nothing of value to humans would grow in such a saline environment; ok, some form of bacteria MIGHT grow in it. Allow the water component to percolate back into the ground; that would partially recharge the underground aquifers while the soil filters out any solids (what layers of soil do best). Harvest any sun-dried "salt" content and MAYBE there is a commerical market for that material, either as "salt" or as feedstock (it might not be all NaCl "salt") to a refining process that recovers any other useful minerals from the solids.
Just look at the Salton Sea in California, a rather brackish water basin; ok, what's left of it. Nothing really grows in that water, but nearby residents do not seem to be offended by it's presence; some even regale in it. Start-up firms have found that region has lithium deposits next to that "sea" that could be recovered & refined. Once the ecologists and the regulators are finished arguing over things in that region there MIGHT still be some commercial interest in recovering that lithium along with any other useful minerals that come with it.
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There's almost certainly some useful application for it.
Farming artisanal Fleur de sel?
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The plume of warm, highly saline, exhaust is a contentious issue environmentally. I suspect this is just the usual greeny lawfare
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Does it have to use solar panels? Plants do it. AI will probably solve this problem some day. How to make a machine that converts maximum sunlight, minimum external resources, and desalinates water into drinking water?
AI came up with the following ideas:
- Photothermal Desalination System: photothermal (such as carbon-based materials, graphene oxide, or hydrogels) that efficiently absorb sunlight and convert it into heat, using the heat to evaporate water.
- Phase Change with Capillary Action: Use materials
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With a lot of luck you might be able to mine it with electrolysis and electro-dialysis for some extra value.
Huh? (Score:2)
Re:Huh? (Score:5, Informative)
You needed to RTFS:
traditional reverse osmosis systems typically require steady power levels
Solar power is not steady. They figured out how to make the desalination process adjust to the lack of steady power. No batteries either. Just solar panels.
It's all there. You can safely skip TFA like the rest of Slashdot.
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I wish somebody could set up aluminum smelting to work like that.
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I'm not sure we really need a zero battery solution, given how cheap batteries are now, but it's still an interesting proof-of-concept that demonstrates one way we might take advantage of basically free renewable energy.
You over-build renewables so that they cover the lowest sun/wind periods, and end up with vast amounts of cheap energy much of the time. Any process that can take advantage of intermittently available energy becomes very attractive. You can easily imagine things like farmers installing large
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Do you really want your access to disaster relief equipment to be bottlenecked by some embargo china decides to impose as it flexes some level of world dominance? Rare earth metals are a finite resource. We can’t battery every fucking thing. Pretty sure if we BEV every damn car it will bankrupt quite a few supplies of rare earth metals. Plus they are heavy. Not exactly village portable.
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What does China have to do with this? They don't have a monopoly on renewable energy, batteries, or desalination.
Besides, it's projection anyway.
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you would be better off taking the residual salts from the process to build ad-hok sodium batteries. you dont need much battery, just enough to serve as a capacitor to fill the gaps if a cloud moves by. Portability is the #1 goal of this. This concept has a 3 pronged approach.
First sales will naturally go to the Industrial military complex. If you suddenly need to setup a forward outpost somewhere you can air drop something like this, with just enough equipment to dig a very small well and set one of these
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But, I'm going to drive a Tesla to pick it up. Get I get funding to do that?
It's one thing to not understand something, but it's quite another to question whether the thing you don't understand was worth funding. Are you a member of congress by any chance?
Help me understand - (Score:5, Interesting)
When I look at the picture in the article, there is a truck with the solar panel and a trailer with the desalination system. So, it is portable, can be driven where needed. They can process 5000 liters per day, approx 1320 gallons. Water usage statistics in the US can be found online for water districts and municipalities - rates vary some, but 300 gallons per day per household seems to be a fair average. Relatively dry places might use much less, so I am estimating maybe as low as 300-400 liters per day per household, let's say 333. Then 5000 / 333 = 15, so one daily batch of processed clean water can serve a water-frugal household for 15 days. A service could drive a truck around to the customers, spend one day on site to make enough water for one house for 2 weeks, then drive to the next customer, then repeat the circuit every 2 weeks, 14 customers net for each rig. Of course, if used in small villages, the business or process model might be different, one truck making enough water for 15 households, repeat every day. You can scale up the technology, make bigger trucks, put more trucks in service or on site, etc.
But here is what I don't get. The project engineers seemed to be obsessively, compulsively, morbidly obsessed with minimizing or eliminating battery storage from the process. Why? If their main goal was to prove that they can match load, their machine, to available power, the sun, and thereby keep the equipment running as efficiently as possible using their ideas about control based on frequent sampling - okay, they proved it. But why not use batteries?
It seems that countless electrical systems are now incorporating battery storage into their machines, even the power utilities themselves. As battery technology and energy storage have developed in the past 10-20 years, it seems like batteries will be a crucial component of nearly all power systems in the future. Why waste capturable energy when you can store it, then use it off hours when the sun isn't shining?
So, why do these guys want to avoid batteries like the plague? Seems like battery would be a useful component to keep the desalination running "off hours", increasing throughput and net yield, perhaps doubling capacity for each truck.
Anyone here on Slashdot have experience with these things and has some insight?
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My guess: Batteries are expensive. Which may affect the "low-cost" aspect of this.
Re: Help me understand - (Score:2)
my guess is that being able to remove the battery reduces the cost of the device. Which means it is easier to produce more.
Assuming you can maintain reliability the same, you would rather not have to service a battery, especially in co text with salty water.
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Shortly after a hurricane there is a shit ton of brackish water from the rain.
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The final use case is more likely a fixed installation in
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But why not use batteries?
Cost. That's just it. One word. One simple idea: the idea that not everyone has endless amounts of money to spend on something and that throwing batteries at everything isn't a viable solution.
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But here is what I don't get. The project engineers seemed to be obsessively, compulsively, morbidly obsessed with minimizing or eliminating battery storage from the process. Why?
This is very, very obvious if you think of it from a practical standpoint, also meaning cost. The batteries are the most expensive part of the system by far. If you can eliminate them, you can build more systems to handle your needs. Putting it on a truck isn't what makes sense long term, it's what makes sense for a technology demonstrator. It gives you two special abilities, one the ability to trivially re-site the experiment, two you can take it to different places to do demos (and those are just more sit
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Because rare earth metals are being dominated and controlled mostly by china. This is a finite resource dedicated mostly to EV as of late. Also 300gal per day includes shit like hollywood showers and laundry. In a pinch you can wash your clothes in a wash basin outside with brackish water. Filtered brakish water is sufficient enough to clean yourself with. After seeing the mudpools people in Afghanistan wash their shit in, anything is possible in a crisis. What you beed fresh water fir is drinking and cooki
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So, why do these guys want to avoid batteries like the plague? Seems like battery would be a useful component to keep the desalination running "off hours", increasing throughput and net yield, perhaps doubling capacity for each truck.
It's a good question, but I think the engineers might have deliberately avoided batteries for a few reasons.
First, batteries introduce inefficiencies -- about 10-20% of energy is lost during charging and discharging. For a system that's already dealing with variable energy input from the sun, avoiding this extra layer of inefficiency might make sense. By directly using the sunlight to desalinate water, they can maximize how much clean water they produce.
Second, batteries are expensive and require maintenanc
Solar powered desalination system? (Score:2)
I thought we already had one of those, and it could provide enough drinking water for the whole country.
Its called the Gulf of Mexico.
Solar still (Score:3)
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What ever happened to the basic solar still, that requires no fancy technology at all?
Thin, rugged, transparent plastic sheets are a marvel of modern technology. :-)
So would be glass panels if they were to create some form of greenhouse, or should it be called a wet house?
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What ever happened to the basic solar still, that requires no fancy technology at all?
It's a question of units. They want to produce 5000 litres of water per day, not 5000 micro-litres of water per day.
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What ever happened to the basic solar still, that requires no fancy technology at all?
A business can not be built around that; therefore, unless you do it yourself, it will not exist.
Read that again. 94% of 21% of sunlight (Score:2)
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If only I had mod points...
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Read that again. 94% of 21% of converted energy (Score:2)
For the past 50 years (Score:2)
For the past 50 years I have been reading about low cost desaliniation systems that will change the world forever.