Efficient Underwater Energy Harvesting from Bubble-Driven Pipe Flow

Bubbles are ubiquitous in water and are unusually energy-rich in the seabed. Harvesting energy from subsea bubbles is a viable solution to supplying energy in situ for underwater equipment, but the existing approaches are unsatisfactory due to low-efficient conversion of bubble potential energy. Here, we propose a novel bubbledriven pipe flow approach for efficient harvesting of bubble energy, which uses the liquid propelled by bubble buoyancy to form a directional pipe flow driving the turbine generator. We perform theoretical analysis of the bubble energy conversion process and the deductions are consistent with the experimental results. The average output power density generated by the new technique reaches 5.84 x 103 times higher than that of the existing bubble energy harvester. This strategy is expected to be a unique in situ power supply technique for underwater Internet of Things application due to its high efficiency and advanced functionality.