Scripps Creates Vessel Powered By Thermal Energy

Stefany Chen/Guardian

Researchers at the Scripps Institution of Oceanography have created an underwater vehicle powered by thermal energy, which they say could run indefinitely.

“We can take energy out of the environment without harming it in an underwater vehicle,” Scripps oceanographer Russ Davis said.

The Scripps team worked with the Jet Propulsion Lab — an organization based in Pasadena, Calif. — to engineer an eight-foot-tall, 180-pound cylinder that runs on natural and renewable energy from the ocean.

The new design can dive at a more frequent basis than the old one — during its three-month trial, the new vessel made over 300 dives, whereas the old model was capable of making only 12 dives in that amount of time. The ability to collect data faster, Davis said, could aid in monitoring worldwide climate change. He said his team hopes to eventually deploy the vessel to replace many of the some 3,000 similar buoys currently scattered across the ocean. The buoys are part of the Argo project, which aims to track seasonal changes in ocean temperature, salinity and velocity.

The new vehicle draws on the energy generated from the natural temperature differences found at different oceanic depths — from the warm waters of the surface to the cold waters closer to the bottom — to recharge its built-in battery.

The charge cycle begins when the battery turns on a motor that pulses oil into a bag at the bottom of the cylinder — which then changes the buoyancy of the vehicle and allows it to rise or fall. As the vessel rises from the middle depths of the ocean, it reaches warmer waters at the top.

A temperature-sensitive wax stored in cylinders throughout the vessel melts and expands when it comes into contact with this thermal energy, and pushes the oil back through the turbine so it can recharge the battery.

When the vessel’s buoyancy changes due to the new balance of oil, it drops back into the ocean and the wax contracts and solidifies — starting the process over again.

“Similar things have been done by using oil for buoyancy, but this is the first time we’ve made a thermal motor for it,” engineer Kyle Grindley said.

According to Davis, this new method of powering the machines will allow vehicles to explore and study the ocean for extended periods of time.

“This technology to harvest energy from the ocean will have huge implications for how we can measure and monitor the ocean and its influence on climate,” Davis said.

The new design was born from one of two originally proposed blueprints. The other design would have been capable of horizontal movement through the water, acting as a glider through the ocean.

According to Davis, the Scripps team may eventually be able to implement this design as well, opening a new range of movement in perpetual ocean travel.

“This is the great thrill of my life,” Davis said. “We’ve been involved in the ‘Rush Limbaugh’ fight in whether the world has been warming or not.”

Next, the Scripps team will re-examine the vessel in an attempt to streamline its complex interior, decrease costs and lower the weight of the vessel to 50 pounds — the current weight of the buoys being utilized in the Argo project.

Readers can contact Henry Becker at [email protected].