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Solar-powered oven makes fresh water


September 9, 2012

The Eliodomestico costs US$50 to build (Image: Gabriele Diamanti)

The Eliodomestico costs US$50 to build (Image: Gabriele Diamanti)

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Sometimes the simplest ideas are the best. Concerned about the lack of fresh water in the developing world, designer Gabriele Diamanti wanted a solution to desalinate water that was available to households rather than relying on giant, centralized plants. He also wanted it to be something inexpensive that could be made by local craftsman. The result is a ceramic solar still called the Eliodomestico that operates like an “upside-down coffee percolator”.

The open-source design of the Eliodomestico is remarkably simple. It consists of two ceramic pieces that sit one atop the other. Inside the top piece is a black container into which salt water is poured. The sun heats the container, turning the water to steam. As pressure builds, the steam is forced down a tube into a container in the lower piece. There it condenses against the lid and collects in the basin of the container.

The Eliodomestico collects about five liters (1.09 gal) of fresh water per day and costs about US$50 to build with no operating costs. The bottom container’s basin is designed to be transported on the head, which is a common practice in developing countries.

The design was a finalist at Prix Emile Hermès competition 201, received special mention at the Well-Tech Award 2012 and was the pro winner of the Core77 Design Awards 2012, social impact category.

Source: Gabriele Dimanti via Fast Company

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

Wow! That is so neat!

Lady Townsend

Simple and Beautiful. With economies of scale it could probably be built for much cheaper. I see the possibilities for many imitations. Which is not a bad thing, as the people that these devices help are not rich.

Nantha Nithiahnanthan

Elegant concept!

Gerard Gallagher

This would probably be even cheaper to build if done locally in the developing world. I like it- a lot!

So many technologies that could help the poor are great in theory but unaffordable to those that need it most- this is to be commended.


Brillante idée sans une facture sallée.

Denis Pageau

Very nice concept for fresh water! Wondering how to use the left over salt at the top though.

Lou Digilio

The salt could used for cooking/seasoning, and could be a source of income if it is packaged and sold. That assumes the water is not particularly nasty. I wonder if it is possible to make clean water from adulterated water using this device.

Bruce H. Anderson

Everybody in my California neighborhood has to buy water for drinking, cooking, even bathing - a larger version of this in every back yard would solve a lot of privatized water problems - well done, and open-source, too!

Jansen Estrup

@nantha: "knock offs" are kinda the point of open source! @Lou: depends on the salinity of the water....I bet that in some places the salt precipitating out of the evaporating salt water will be nearly as valuable as the water itself.

Bryan Paschke

Was the efficiency of this device measured in relation to others such products, and in relation to its price? If the inventor can prove that his is the best product we can help him in spreading this.

I suspect this is neither a new concept, nor the cheapest.

Siddharth Mehta
Unfortunately, unless you start with pure water and pure salt, you will not be left with pure salt after the desalination process. Sea water is not simply salt+water. Other chemicals, as well as organic material will be left over after the pure water is precipitated out. RikJamez

Dig a shallow hole in the ground, place a lose sheet of thin plastic over the hole (be sure to put enough weight around the edges of the plastic so it will not be pulled down completely by the weight of the water it collects overnight), place a vessel at the middle of the hole and under the sheet of plastic to collect the water overnight and put a small rock at he middle of the plastic sheet to create a slight incline towards that center and wait till morning. Depending on how large the hole, sheet of plastic and container for the drinking water you will have drinking water. Those who grew up in the desert should already know this and those who are considering moving to the desert should learn how to create water out of the thin air.


Oops, I forgot to mention in my previous comment that I want one of these in my survival gear.


Siddharth Mehta, It is compared to a normal solar still in the picture sections. Makes 5 liters as compared to 3 liters for the normal still and costs half as much.

Page Schorer

It is a nice design, but it is nothing more than a solar still. As YukonJack said, a sheet of plastic , a shallow depression or large pan, and a collection cup will do the same thing, and weigh far less and cost less.

If you take a large shallow pan such as a kiddie pool, put a collection pot in the center, fill it with undrinkable water. (salt/dirt) stretch a sheet of plastic tautly over the top to seal it, then add a weight in the center of the pool directly over the collection pot, the sun's rays will distill that water into condensation on the plastic roof which will drip into the collection pot. The larger the surface area of the shallow pan, the higher the amount of water collection from condensation. This is a basic survival technique called a solar still. There is a blow up version now available for life rafts at sea.


I am pretty sure a black pot without any kind of concentrator will not boil in the sun, even in the desert. It will create a moist vapor by increasing how much humidity the air can hold by heating it, but I don't see how this design would work any better than the traditional solar still designs.

Michael Crumpton

Yukon Jack is right. I've used the plastic sheet and bowl method to collect water from moist ground and to distill muddy or brackish water.

The Eliodomestico is an artsy looking piece but $50 is a month's wages for the people who actually need this device's capabilites.

Guy Macher

Nice concept, however, USD 50 is tad too expensive for such a device, specially for a developing nation. Further, the efficiency would be greatly dependent on the weather. Cold and rain season would be a problem; and water borne diseases are specially prevalent in these weather.

If low cost is the consideration, then Tata Swach (http://www.tataswach.com/shopping/product_index.aspx) which retails for about USD 20 is worth a look.

Its supposed to use nanotech and cleans water to be US EPA standard compliant. Capacity is about 3000 liter annually i.e. about 8~9 liters a day and uses no electricity. Further its designed, manufactured and sold by a USD 79 billion company, so after sales support is good (I know people who have bought it).

It requires cartridges (bulb & mesh) to be replaced after 3000 L i.e. about once a year, however, at less than USD 10 per set, USD 50 would fetch your at least 4 years of operations.


They teach this principle in the Boy Scouts. You dig a pit, place a container in the center, cover the pit with a black plastic garbage bag and secure it, then put a rock in the center just above the container. The sun warms the air in the pit and draws moisture up from the soil which condenses on the inside of the bag and drips into the container. It's slow, but produces fresh water.


Stunning Design, I love it, very pleasing visualy. If it's performance is a good as claimed I certainly applaud it. Features I'd like to note: Less subject to problems from strong winds than other designs, but not very portable. Depending on environment, critters can get into finished water, solvable with screening. It be good to have all of the metal items of the prototype to be plastic instead. Size oriented to needs of just one or two people, who need to stay in one location. Salt accumulation in top part will need to be periodicly rinsed out, or dumped if dry.

Long available Quick & Dirty Alternates: As described in several comments above http://en.wikipedia.org/wiki/Solar_still

Industrial fabrication, inexpensive in quantity, not very pretty, not compact but light when empty, may be easier to tell if clean. Watercone desalination system http://www.watercones.com/

Tata Swatch is a "water purifier" IT CAN NOT REMOVE SALT. It's marketed to purifiy already drinkable tap water.

Dave B13
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