Our solution

Our product

Refugees have to stand in line all day to get drinking, or sanitation water. A large proportion of the transmission of COVID-19 takes place in those queues. The shortage of clean water therefore impacts the spread of the virus. When looking at camp Moria’s surroundings, it becomes apparent that the refugee camp is close to the sea, so there is an abundance of seawater. However, seawater is not drinkable. That is where our solution comes in.

By distilling sea water with solar energy, clean water is produced in a free and sustainable way. We are making use of some very abundant resources: the sea and the sun. In the morning the seawater storage tank on the top is filled with seawater. Then the watertight cap gets screwed on extra tight, after which Solar Still is ready. Solar Still then stands in the sun, and after 24 hours the clean drinking water can be collected from the storage container, which is locked by a key in possession of the owner of Solar Still.

By providing efficient and easy to use seawater distillation systems, we reduce the need for queuing, hence lowering the transmission rate of COVID-19 in Camp Moria.

How does destillation work?

The principle of Solar Still is based on a simple construction. It essentially comes down to the separation of salt and contaminants from the water through distillation.

Distillation is a way of separating a liquid from the solids and liquids dissolved in it. In this case the liquid is seawater, in which all kind of pollutants including salts are dissolved. A heating source separates the two components trough a difference in boiling point. The desired liquid substance will then evaporate and is then cooled down and caught in a liquid state. The residue of all the dissolved solids and liquid does not evaporate and remains. This residue is called brine. In the case of Solar Still, seawater evaporates and the vapour is caught in another container where the temperature is lower so that the clean water condenses in the fresh water container.

Distillation of water demands a great deal of energy. In nature, evaporation of water is a key process in processes like cloud formation. Natural evaporation processes are powered by the sun. this is a free, reliable and powerful source of energy. This is used in the most low tech solution using distillation: solar thermal powered desalination.

Solar thermal-desalination methods use sunlight in the infrared spectrum to power the desalination of salt water to drinking water.

The technical process

Solar Still works by  the heating of the black boiler. The water will start to evaporate as the temperature and pressure in the boiler rise. Because of the increase of temperature and pressure the water will boil faster and faster. The created steam will go through a connection pipe to the condenser, in this case the water storage tank. The transport of the steam happens as a result of the pressure that is built up in the system. There is higher pressure in the boiler than in the connection pipe and condenser.

In short, the sea water is evaporated and then caught in the storage tank The residue of impurities and salt will stay behind in the boiler. This is the technical process of Solar Still.

The effieciency of this system is based on the separation between the boiler and the condenser units. This principle is from the opensource project of Eliodomestico opensource project by designer Gabriele Diamante. To honour this our product is open-source and can be used by anyone, as long as it is kept open-source.

Materials

Our design consists of several parts. All of these parts require specific material properties. Hence, they will all consist of different types of plastics, or polymer blends. When deciding on which material to use, we aimed to find a balance between optimal material properties, biodegradability and cost-efficiency.

The body of our product and the storage container will be made out of a blend of polystyrene (PS) and polylactic acid (PLA), with zinc oxide (ZnO) added into the matrix. We chose this material because it can be injection molded and has a good resistance to water and ultraviolet light. It can also be used to store drinking water safely, without contaminating the water. 

The boiler will also consist of the aforementioned material. The boiler should be black, in order to have optimal heat absorbance. To achieve this color, we will use a copolymerization technique with graphene based photonic crystal (SGPC) immersed in tetrahydrofuran (THF). The color then becomes a property of the material itself, which is preferable over painting the material, because in this way the black color will not fade. We will use a thin film to cover the boiler, in order to ensure that it does not get damaged through extreme weather circumstances, such as humidity and heavy wind. This will be made out of polypropylene carbonate (PPA) combined with cellulose acetate (CA) to cover the boiler. We have chosen this material because PPA.CA films have excellent transparency. Transparency is important, because otherwise the black color of the boiler will not be visible. 

For the sealant we will use a blend of polyhydroxy-butyrate (PHB) and polymethylene oxide (PMO). We will combine this with poly-butyl acrylate (PBA). This will give the material rubber-like properties, so that it can be used to seal the water compartments.

All of the materials we will use are biodegradable. PLA is also made from organic and renewable materials. This means that our product is environmentally sustainable.

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