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ULTRA SolarStill

A sustainable domestic device that is used to desalinate brackish and seawater to clean freshwater using sunlight and ultrasonic waves at low cost for communities in remote and rural areas.

What it does

Freshwater scarcity is a global issue especially in remote areas that lack natural freshwater resources. The ULTRA SolarStill is a sustainable domestic product that is designed to convert brackish and seawater to drinkable water reliably and durably.

Your inspiration

Drinking contaminated water causes disease such as diarrhoea and cholera. In fact, more than 800 million people around the globe currently do not have access to clean water and it is expected that this number will increase up to 1.8 billion by 2025. This is because only 3% of the planet's water is drinkable and unfortunately only 1% of it can be easily accessed by rain and rivers. Desalination plants convert seawater to clean water efficiently, but these plants require tremendous energy and costs. Therefore engineers should accelerate in finding new reliable, sustainable and affordable domestic solutions to make freshwater more accessible.

How it works

The ULTRA SolarStill is a two-chamber design that is capable of producing 4 Liters of freshwater per day sustainably. The ultrasonic mist makers generate salty mist (fog) in the Ultrasonic Box and then taken to the solar still chamber through a flexible duct. An ARMAX glass panel that features an anti-reflective coating transmits 94% of incident sunlight through to convert the mist into vapor. Then vapor condenses after it makes contact with the sloped glass panel, and due to the panel's inclination, the freshwater condense will slide down until it is contained inside the Double Slope Trough and to the freshwater tank.

Design process

We designed the ULTRA SolarStill to include a set of effective enhancements that mainly utilizes solar energy and ultrasonic waves to make it productive, sustainable and affordable once in mass production. The first design stage had the mist makers operate inside the solar still chamber. Afterwards, Two main challenges were taken into consideration: which were the mist makers' water depth limits 5 cm and that they cant withstand high temperatures inside the meter-squared solar still. The second design included two containers welded into the basin from below to store the devices. This approach solved the water depth issue but not the overheating, which finally lead the team to design a two-chamber system that separates the mist makers from the solar still by a flexible duct. Galvanized steel was selected for the solar still frame and copper for the basin. However, since steel is heavy and can be more subjected to rust and copper got expensive due to the pandemic, then aluminum was picked as it serves anti-rust, low weight and cost capabilities. We redesigned the trough from the traditional single slope one to be double sloped with a mist separator to prevent mixing between the mist and freshwater and to make it easier and cheaper for manufacturing.

How it is different

The ultrasonic technology added a new approach to increase the productivity of solar stills, that is due to the rapid evaporation of the salty mist as compared to a liquid-based seawater when subjected to sunlight. The anti-reflective coated ARMAX glass panel is a great contribution as achieving 94% of sunlight transmissivity is unique and extremely productive. Also, we introduced the new Double Slope Trough design which is first of its kind that increases the freshwater droplets accumulation, eases the welding process and reduces the manufacturing cost compared to the traditional single slope trough. The two-chamber approach is a unique design that ensured reliability and durability of the system in terms of preventing the devices from overheating. All of these new unique enhancements allowed the ULTRA SolarStill to desalinate 4 Liters of freshwater per day, which is more than double of what a conventional solar still can make, achieving a cost of $0.13/L.

Future plans

The ULTRA SolarStill prototype proved its capability of producing more freshwater per day than conventional solar stills. We collected all the needed data from the previous tests that will allow us to continuously improve our product and explore new designs that can benefit the most from the new ultrasonic technology in making it more productive, cheaper, and compact for lower weight and transportation purposes. Once the product enters mass production then the costs can be significantly reduced since its a first stage prototype. We hope that we can improve it more to be ready and more compatible for commercial purposes.


First place in the Think Sustainability competition organized by the Deanship of Student Affairs in the University of Sharjah. Nominated for the 8th Undergraduate Research Competition organized by Abu Dhabi University.

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