The improved efficiency of the product is a real stand out feature; it’s a big limitation of solar water purifiers and this unique design offers triple the output of conventional stills.
The fact that the designer has made this open source is such a clincher–it’s one way of ensuring wider adoption of the product for greater impact.
It is highly laudable that the product is designed to be manufactured by local craftsmen.
Eliodomestico is an open-source eco-distiller running on solar power, to provide safe drinking water for people in developing countries: a very simple way to produce freshwater, starting from sea- or brackish water.
The device produces 5 liters daily, through a direct solar-powered distillation process. Compared to traditional solar stills, Eliodomestico is almost 3 times more efficient.
Eliodomestico works without filters nor electricity, and requires minimal maintenance. Made from readily available materials and poor traditional technologies, the system has no environmental impact, and delivers positive outcomes for local economies, because it’s designed to be produced (and eventually repaired) by local craftsmen.
Many people in the developing countries do not have access to adequate and inexpensive supplies of potable water. This leads to population concentration around existing water supplies, marginal health conditions, and low standard of living.
By the year 2025, 2/3 of the world population will lack sufficient fresh water. The areas with the severest water shortages are the warm, arid countries in northern Africa and southern Asia within the latitudes 15-35ºN. Moreover, the regions in most need of additional fresh water are also the regions with the most intense solar radiation. In view of these facts, desalination seems to be the only realistic hope for a new source for fresh water.
According to the WHO, the desalination process can ensure the safety of drinking water because it’s able to kill microbes, germs, and to eliminate any kind of dangerous salts, like magnesium and arsenic. The desalination process can be applied to different source waters like waste water, brackish and seawater.
But the solar distillers now used in the developing countries are either too difficult to use, or too expensive, or they are built with inappropriate materials and technologies. As a result, many of these items can be operated just by qualified personnel, and if they get broken it’s very difficult to find spare parts (eg glass). Moreover an average solar still produces a mere 3 liters per square meter per day.
My challenge was to find a new kind of solar still, using the design thinking to solve these problems.
Most of the development work about desalination for poor countries has been directed toward reducing the construction cost of solar basin stills, but less effort has been devoted to technical improvements which might increase distiller efficiency and reduce the necessary size of a unit for a certain water production capacity.
So I decided to create a completely new kind of solar still, very different from the classic basin still. I wanted to increase the efficiency, reduce the size, transform a big equipment in a compact household, very easy to use and to understand.
Indeed my goal was to conceive it like an household: something that works autonomously during the day, just in front of people’s houses.
“Eliodomestico” is a combined word I invented to describe this innovation: translated in English it sounds like “Sun-household”.
Its design is inspired from archetypal forms and materials, because like any household it has to be highly recognizable: as a matter of facts, one of the biggest problems in delivering technologies to the developing countries, is that usually people doesn’t understand them. That kind of archetypal design is a good way to solve this cultural problem, so I put it in the brief.
I also decided to go really low tech, so that Eliodomestico would be feasible in any context, with a very low budget, creating a kind of “distributed manufacturing”: a self-sustainable craftsmen’s network, eventually financed by micro-credit.
When I invented Eliodomestico, I started from the very beginning: I made a wide research, visiting places, reading books and reports, studying the physics of water. I had the opportunity to meet international experts, like doctors working with WHO, solar equipment-specialized engineers, development aid experts.
I made research and experiments in order to prove if my insights were correct. The theory was believable but I had to prove it, so I made a small-scale prototype with scrap materials. The home-made model was tested with a 300W halogen lamp, placed at 10 cm from the surface, to simulate the sun. This system, although not very accurate, is very useful to simulate the average power of the solar radiation during a day at the temperature of 20°C, which is also the condition which is normally considered to be the annual average in places like sub-Saharan Countries.
After a lot of trial and error, I adjusted the project till the current setup:
- The evaporator is completely separated from the condenser, and the second one is under the shade of the first one (thus increasing the temperature Delta between the two, thanks to the shade). This increases the efficiency of the system;
- I built the evaporator to let the pressure grow in it: this pressure force the steam down in the pipe to the condenser. As the steam expands in the condenser, it cools down faster, thus increasing the efficiency;
- The construction of the Eliodomestico allows to use a metal (steel, aluminum, …) as a building material for the condenser. This increases the efficiency very much compared to the classical basin still, were the condenser was a glass (which is a bad heat conductor).
After that, I went to a potter with the final drawings and I followed all the process from the shaping on the potter’s wheel to the firing. Thanks to the potter I had the opportunity to adjust the design further and to solve some production issue.
So I came up with the final prototype, completed with the metal parts, and tested it under the sun.
Now the distiller is very easy to use: in the morning simply fill the water tank with salty or dirty water from a local source, and in the evening collect clean, evaporated and re-condensed water in the portable recipient placed underneath the tank.
Finally, I met some NGOs to plan the further development.
At the moment I have an agreement with 3 of them, in order to make the following steps:
- to make rigorous chemical testing of the water;
- to bring the drawings to african craftsmen, in order to test the local production issues;
- to start a project of production and marketing of Eliodomestico, partially financed by the NGO, and partially by micro-credit, directly given to the craftsmen.
Eliodomestico should have a huge social impact: it can release the poor people from the dependance on spending time, miles, money, to get some clean water.
It can deliver very positive outcomes for the local economies, because it’s designed to be produced (and eventually repaired) by local craftsmen, thus generating a market.
Craftsmen from many different places can produce the distiller, using the materials that they already can manage. The production techniques are very sustainable, already present in the developing countries, so there is no need to teach anything to the craftsmen. The materials needed are very cheap and common.
I put a big effort into designing a very usable object.
After a wide research on the African cultures, I discovered that the form and the materials are really important for such a project: there is plenty of examples of failures in the attempts to introduce new objects/concept in the rural and poor areas of the world. The failures were always caused by objects too far from the people’s collective imagination, mostly causing a refusal of the innovation, or in some case a misunderstanding of the object’s purpose.
A new object has to be simple to understand. Its shape has to remind traditional archetypes, it has not to be alien, and the materials involved in the production have to belong to the local traditions.
Best of all, the object might be produced by locals, because making is the best way to understand.
This is maybe the biggest value of Eliodomestico.
In one word: thanks to the research.
The brief itself was actually a translation of the needs that the communities expressed to me and to other researchers in the past.
So I started everything from the expressed desires of the people in different areas of the world.
Moreover, I had a lot of positive feedback after the publication of my project. Feedbacks are confirming that this could be the right path to follow… off course this project is not suitable for every place in the world, but in the rural areas, where it’s difficult to access electricity supply, and where the traditional crafts are still surviving, this could be the “Columbus’ egg”.
Eliodomestico is made for poor people and it’s designed for small series crafting, using poor materials and traditional techniques.
I didn’t patent it: it’s free to anyone who wants to produce it. There’s just a Creative Commons attribution, non-commercial, share-alike License.
This is the strength of the project in terms of economical sustainability: anyone can reproduce it, without paying anything.
The local production will create a market which is auto-sustainable: the craftsmen will produce Eliodomestico (eventually starting with a micro-credit program), and the people will use it. Using the device, they will save money (it pays itself in 3 to 6 months), so they will have money to buy other pieces, or to let their devices be repaired by the same craftsmen who build them.
The idea of the household can solve another big problem: very often the technical equipment provided by NGOs are abandoned as soon as the development aid mission is over. One of the biggest reason is that the equipment is often property of an entire community. In many cultures this means that it belongs to no-one. So (for example) it can happen that after a couple of months someone starts to take pieces away from the device, to use as a building material. And the project dies.
With the concept of solar-household, every family will care of one device. So every device will be property of a single, not a community, thus giving a sense of responsibility and preventing the deterioration.