Rechargeable Underwater Drones Using Differences in Water Temperature

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A former NASA scientist, Yi Chao, developed severe seasickness after spending a week on a ship. For this reason, he decided to explore the possibility of remote ocean studies.

The outcome of his exploration was the energy-harvesting technology that recharges underwater drones.

The Foundation

The research community treats the ocean data collection drones and gliders as disposable devices. The role of the devices ends after the community receives the required data.

In addition to wasting money, treating the devices as disposable increases the level of ocean pollution because the lithium-ion batteries of the drones are toxic waste.

Chao’s energy-harvesting system generates renewable energy that can power ocean drones.

How the Energy Harvesting System Works

The energy harvesting system that Chao’s California-based Seatrec developed has a basis on the process of changing substances from solid to liquid and then to gaseous form using heat. The company leverages on the pressure changes during the changing phases to generate energy.

The company capitalizes on the difference between the warm ocean surface water temperature and the temperature of the cold ocean depths water. The buoyancy change of a robotic probe generates additional electricity by either floating or sinking.

An external energy-harvesting module transforms robotic probes into rechargeable devices that are reusable. The resultant renewable energy keeps the drones running. It also prevents them from developing mechanical or electrical breakdowns.


The U.S government and military are the latest potential consumers that have shown an interest in Seatrec’s products. The parties are after the collection of oceanographic data and analytics.

Seatrec has also won two prizes worth $10,000 each in 2020. The company split one of the prizes with the Northrop Grumman because of a joint mission that the two companies undertook together.

The Future

Seatrec eyes to introduce its technology to other commercial ventures that engage in underwater farming and mining. The selling punch line of the company centers on the environmental impact of the technology, making it a sustainable source for the future.

For more insights, watch the video below on the top 6 best underwater drones.

Source: IEEE
Photo: Seatrec