over 4 years ago by fsteckel
Which problem are you trying to solve?
Many people don’t have enough water to sustain health or irrigate land to grow food. They need companies selling them
water for high prices. Wells are overused, thus sinking the ground-water-level.
How are you going to solve the problem?
By developing simply produced solar water-desalination systems, easily affordable in the 3rd world. Instructions via
online videos and in local schools for students to build and spread the word.
What is the impact of your project?
It impacts all 4 categories:
Ecological: People can grow their own food.
Education: Local schools build and
Health: People get enough water and food.
Refugees: Refugees might not need refuge.
How can the project be manufactured in the OpenLab?
Prototype needs sheet-metal cutting and drilling. 3D printing is used for producing bending-rigs for tubes.
Tube-fittings are 3D-printed or lathed. Experience of other makers can flow into the design.
Describe your project in detail
The desalination system consists of two main assemblies. One (thermal) Solar Collector Array (SCA) and the Multiple
Effect Desalination (MED) unit.
The SCA consists of several solar panels. These are made of sheet metal plates painted
black on the front side. Two sheets are separated by aluminium profiles. The back and the sides are thermally insulated
using cork. 3D-Printed fittings for garden hoses (i.e. Gardena) are integrated into the panels. Water flows through
these cheap units absorbing the heat of sunlight.
The MED unit consists of discrete stages (called ‘effects’). In
the first effect, the heat of the SCA is used to evaporate sea water under a light vacuum (~0.4-0.6 bar to lower the
boiling temperature of the water). The water vapour is guided through tubes that are routed inside the second effect.
Inside these tubes the water vapour condenses into fresh water, releasing its latent evaporation heat into the second
effect where more sea water is thus heated. It evaporates, producing water vapour in the second effect that flows into
the third effect, and so on. To increase the salt-water’s surface area and promote heat exchange from the tubes into
the salt water, shredded aluminium foil is integrated into the effects.
The condensed fresh water is sucked out of the
tubes using cheap vacuum pumps. The enriched salt water that remains in the effects is also sucked out after a while and
needs to be collected and put back into the sea.
The MED unit is built in a similar way as the solar panels: Using
sheet metal and aluminium profiles. Its geometry is slimmer as the unit needs to withstand the negative vacuum pressure.
The effects are located next to each other.
The general design principles of this system are:
1. To use the cheapest
possible raw materials, e.g. sheet metal or aluminium foil, that are abundant even in the poorest of regions.
source very cheap components. Due to recent upswings in personal international trade, this is now possible for private
persons. E.g. the vacuum pumps that can be obtained for very little money from China.
3. To make the units buildable
with general available tooling. Should there be special tooling necessary, we will need to source cheap tools to provide
with the unit.
4. To make the units easily repairable. By providing the full design documents to the end users and
providing educational videos how to build/ maintain the units, end users will be empowered to take care of their systems
5. To make the units fool proof using modern open-source control logics, e.g. Arduino/ Raspberry Pi.
one of the project's central goals to include local schools, where the pupils will build these units for their
school. This will generate a deep understanding for the systems. Schools will then be able to provide courses for
interested farmers to educate the community on how to build/ take care of the system. This will provide an excellent
option for sponsorship for EU Governments or even private persons to sponsor schools with such a system or providing
micro-credits to farmers.
For more details watch the video presentation at: