A group of engineers at UNC Charlotte traded their labs here in Charlotte for the beaches of North Carolina one long weekend back in April. But this was not a relaxing beach trip.
“It was completely dark outside,” UNC Charlotte engineering student Allison File said. “You could hear the roar of the waves.”
At Jennette’s Pier in Nags Head, North Carolina, this team of engineers — known as the WATER BROS — were about to see the culmination of almost three years of work: They were testing a device in the U.S. Department of Energy’s nation-wide Waves to Water contest.
“I just remember walking off the pier and I couldn't stop looking back. ‘Is it still there? Is it still OK?’” UNC Charlotte engineering student Abby McConnell said. “There was a lot of nerves. But it was mostly overshadowed by excitement and pride and happiness.”
The Waves to Water contest challenged engineers from across North America to develop a device that would desalinate water — turning the ocean’s saltwater into clean, drinking water — by harnessing the power of the ocean.
The entry at UNC Charlotte was started by engineering professor Wesley Williams and Raleigh-based engineer Landon Mackey back when the contest first started in 2019.
While desalination is by no means new, the contest challenged engineers to build a device that could power that energy-intensive process by converting the ocean's waves into electricity, Williams said.
“Having seen recent disasters like hurricanes hitting Puerto Rico — when the (energy) infrastructure is out — the lack of water becomes an issue really quick,” Williams said.
But the device also can be useful for coastal communities without easy access to water infrastructure or an energy grid.
“There are a lot of people that don't have the reliable access to clean drinking water that we take for granted here in North Carolina,” Williams said. “This could help them.”
For those natural disaster situations, the device developed by the WATER BROS — which stands for Wave Actuated, Tethered, Emergency Response, Buoyant Reverse Osmosis System — can create clean drinking water for around 30 to 40 people daily depending on wave conditions, Williams said.
That would hopefully reduce the number of water bottles that need to be shipped to disaster sites, Williams said, which is how emergency agencies currently respond to water access issues caused by natural disasters.
The device works by pressurizing the ocean’s saltwater and pushing that pressurized water against a membrane that blocks the salt and lets a fraction of the water — around 10% — in as drinkable water, Williams said.
While that is how desalination has traditionally been done, the device at UNC Charlotte powers its device similarly to how a pull cord works on a lawnmower.
The device is attached to an anchor and — as the device floats up and down with the waves — that movement pulls a cord that rotates a drum in the device, creating the energy needed to desalinate the water, Williams said.
Converting the energy of the waves into energy is not particularly easy since the ocean has a lot of force but not a lot of velocity, Williams said. But that being said, he says the ocean has one advantage: consistency.
“Being that the waves are reliable 24 hours a day — as long as it's slowly producing that —with every rise of the waves, we're pushing a little more freshwater through,” Williams said.
But there were also other challenges as well. For starters, ocean water is not easy to work in.
“It's corroding everything that it's touching," McConnell said. "We put a bunch of stuff in saltwater for months just to make sure it wasn't going to corrode… Every single aspect had to be evaluated to see, ‘OK, what's the ocean going to do to it?’”
Plus, the power of the waves themselves can cause issues.
“The ocean is a powerful and unpredictable thing, so a lot of failure analysis went into every single aspect of the entire thing,” McConnell said. “You're putting your device into something that can rip it to shreds with just the power of the water.”
Each of the four devices in the final test at Jennette’s Pier became untethered due to the weather conditions. While the testing period was originally slated for five days, it was cut down to only one night.
At the end of the contest, the engineers at UNC Charlotte were one of the four finalists, and they received $178,000 from the U.S. Department of Energy for their device's performance at Jennette’s Pier. Throughout the entire contest, the team received $415,000 in funding from the Department of Energy.
By making it to the finals, the WATER BROS had to beat out almost 70 competitors from a variety of backgrounds, ranging from university engineering programs to private sector companies.
The WATER BROS were also the only university-affiliated team in the finals, beating out teams at other schools such as Massachusetts Institute of Technology and Oregon State University.
The contest’s judges said the device developed in Charlotte was able “to generate clean drinking water even in the harshest of conditions and has the potential to be rapidly deployable, low cost and highly resilient — optimal for emergency response.”
The WATER BROS device was also the lightest in the contest, too, making deployment possible without any specialized equipment. Their goal was for three people to be able to deploy the device on their own.
“The other devices were all significantly larger than ours and significantly less normal looking,” McConnell said. “We like to joke that we were the little buoy that could.”
This philosophy was a big part of the team’s design process.
“It was important for us to have a design that was straightforward and serviceable,” Williams said. “If someone is dependent on this for fresh water in a disaster, if it breaks down, they need to fix it themselves. We want to empower the people that are using this for their water supply to go fix it themselves.”
Even though the contest is now over, the WATER BROS say they are not done. They're working on optimizing their project for real-world applications outside the contest's structure.
“We're definitely looking at getting more data, so we can work on our next prototype,” File said. “But the WATER BROS are definitely not going anywhere. We're still working on it.”
Plus, McConnell said that the potential impact their device could have on people dealing with natural disasters adds a lot of meaning to the project.
“I've always had this feeling like I want to make a positive change in the world,” McConnell said. “The thought of being able to help that many people — especially people having basically their worst days of their lives — is a really good thought.”
Canada-based Oneka Technologies was the winner of the Department of Energy’s $500,000 grand prize with a device that can produce 7,000 liters of water per week.