SOLO-TREC is outfitted with a series of tubes full of waxy phase-change materials. As the float encounters warm temperatures near the ocean’s surface, the materials expand; when it dives and the waters grow cooler, the materials contract. The expansion and contraction pressurizes oil, which drives a hydraulic motor. The motor generates electricity and recharges the batteries, which power a pump. The pump can change the float’s buoyancy, allowing it to move up and down the water column.

“In theory what you have now is unlimited endurance for something that has this type of engine,” said Thomas Swean Jr., team leader for ocean engineering and marine systems at the Office of Naval Research, which funded the project. “Other things can break, but as far as the energy source, it will only stop working if the ocean ran out of energy, which is unlikely to happen … One of the Navy’s goals is to have a persistent presence in the world’s oceans. This is the type of technology that leads you to that.”

[via Neatorama]


Sean Michael Ragan

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c’t – Magazin für Computertechnik, and The Wall Street Journal.

  • dZed

    Gotta love those two words “in theory.” Cover all manner of omissions, don’t they?

  • RocketGuy

    On a slocum glider. Apparently unlimited endurance is possible for a underwater buoyancy glider. Not incredibly efficient, but it still had the equivalent of a 40W output with a single moving part (valve). In that arrangement the oil was used to move the buoyancy piston in and out for dive/surface phases of the glide.

    Nice to see that the research is still ongoing, anybody know what the phase change materials are? The paper I read on the glider was also very vague about the “waxy materials”

  • RocketGuy

    I didn’t read closely enough, this version is producing electrical power in enough quantity that they can afford the conversion losses for the hydraulic buoyancy pump to be electric as well as produce leftover power.

    Impressive improvement in the technology.

  • Shadyman

    “Eternally” and “battery” in the same article? Hmmm.

    I’d think they’d have better luck with a supercapacitor or something similar.