The Odyssée desalinator: Using the power of the ocean to cleanse its own salty waters
Watching on as the waves crashed against the cliffs of South Corsica, France, mechanical engineer Dragan Tutić knew some were already drawing on power from the ocean to generate electricity. But a possible use for all that motion in the ocean that had been largely unexplored, as far as he knew, was turning its salty seawater into the fresh, drinkable variety on the spot. In the following two and a half years, Tutić and his team designed and tested a prototype for a wave-powered desalinator, and now hold hopes of deploying the system in regions where water scarcity threatens the survival of coastal communities.
"How is it possible that even today we basically don’t use this infinite reservoir?" Tutić asks, recalling the moment that the idea for a wave-powered desalinator first came to him. "We should just take the resource and the energy to transform it at the same place. With the colliding of different concepts I’ve seen previously, I realized it was possible."
Around one month later, Tutić teamed up with eight of his fellow students at Sherbrooke University in Quebec, Canada, and got to work on making his vision a reality. Their design for the Odyssée wave-powered desalinator involves a hydraulic cylinder pump attached to buoy that floats on the surface of the water. As ocean swells move the buoy up and down, it kicks the pump into action. This builds up pressure and drives oil through a hydraulic motor, which in turns converts the linear motion into rotary motion.
Connected to the motor is a water pump that combines with a reverse osmosis system, a water purification method that uses membranes to separate water molecules from salt ions, bacteria and other unwanted particles. Using torque from the hydraulic motor, the desalinated water is then pumped back to shore though a small tube.
"The key thing is that it is an all-in-one-solution," says Tutić, describing what makes his system unique. "It’s the power plant and the desalination plant at the same place. Furthermore, its simplicity makes it less expensive than similar technologies."
Systems that use wave power to desalinate ocean water have been floated in different parts of the world before. In 2010, a company was given the nod to build an 18-pump wave power generation facility in the Gulf of Mexico that would feed water to and power land-based desalination plants. Off the coast of Western Australia a similar system called CETO became operational earlier this year.
Though the Odyssée system is rather small in comparison, Tutić says if more output is needed then the number of units could easily be increased. The first prototype was intended to produce 10,000 L (2641 gal) of water per day, but the size of the system and the equipment needed to install it has steered the team toward a more compact and portable design.
"We never had the chance to do sea installations or operations before our tests at the Magellan Islands," says Tutić. "It was at that moment we realized how much more complex the system was than we had expected. This is the critical point we want to improve for our next version. We want to make it extremely easy to install with minimum equipment."
These logistical issues proved problematic when the team first took their system to the ocean in September. The strength of the currents meant that it had to abandon the main anchor and instead use a lighter version. Although the backup anchor was heavy enough for them to test the system’s energy harvesting capacity, it was too light to conduct the desalination process.
"We installed it and the machine pumped pressure up to the limit of the anchor," explains Tutić. "We capped at about 30 percent away from the necessary pressure, but it was such a relief to see that the buoy was indeed sending the power to the prototype as we hoped it would."
With the knowledge acquired throughout two years of research, development and testing, Tutić’s team is now knuckling down on the next generation Odyssée wave power desalinator. Part of this involves trying to raise CAD$10,000 (US$8,600) on Kickstarter to develop a more accessible, affordable and efficient system.
The second prototype will be designed to produce 3,500 L (925 gal) of water per day and if all goes as planned, will use a simplified energy conversion system with less components. The team hopes to develop a one-piece system for better mobility and to reduce its overall size and weight.
While it is still very early days for the Odyssée wave power desalinator, Tutić and his co-founder Renaud Lafortune do hold high hopes for its ability to deliver clean drinking water to regions in need. Potential areas for deployment include South Africa, Madagascar, Australia and smaller islands susceptible to the impacts of climate change.
"We would like to start collaborating with a community or population right away," says Tutić. "To make them involved in the development so it does fulfill their needs as they would like."
You can check out the pitch video below and head over to the Kickstarter campaign if you’d like to get behind the project.
Source: Project Odyssée