Underwater Robot Powered By Ocean's Thermal Energy

separsons writes "A team of scientists recently created the world's first underwater robotic vehicle powered entirely by renewable ocean thermal energy. Researchers from NASA, the Scripps Institution of Oceanography and the US Navy developed Sounding Oceanographic Lagrangrian Observer Thermal RECharging (SOLO-TREC), an autonomous robot that runs on a thermal recharging engine. The engine derives power from the natural temperature differences found at varying ocean depths. SOLO-TREC produces about 1.7 watts of power each dive, enough to juice the robot's science instruments, GPS receiver, communication device, and buoyancy control pump. SOLO-TREC is poised to revolutionize ocean monitoring; previous robots could spend only a limited amount of time underwater because of depleting power sources. SOLO-TREC can stay beneath the surface of the waves for indefinite amounts of time. Based on SOLO-TREC's success, NASA and the US Navy plan to incorporate thermal recharging engines in next-generation submersibles."

Comments

Re:1.7 Watts of power each drive

[Anonymous Coward]

DeLoreans are submersible, but I don't think they ever make it back to the surface, so you'd better hit your 88 MPH on the way down.

Go "further", more passive?

[sznupi]

I wonder...with the temperatures in the deep quite predictable, likewise at the surface in targeted time period and location, perhaps underwater glider with buoyancy control via passive mass having "weird" thermal expansion properties would be also feasible? Who knows if worthwhile though, with less precision and need for control pump anyway, for surfacing...

Re:1.7 Watts of power each drive

[WrongSizeGlass]

FTFA, it's 1.7 Watt-Hours (6100 Joules) generated, rather than 1.7 watts. It's still peanuts though really.

It true that 1.7 Watt Hours isn't much, but it doesn't need to be a lot, it just needs to be enough.

Re:How hard can it be?

[fuego451]

"How far can a 80 mph car go?"

About 580,000 rods per hogshead, depending.

Re:GPS?

[Bearhouse]

Hm? Underwater GPS receiver? I am quite sure that the readio signals from the satellites do not pass through water....
Did I miss something?

The spell check?

Re:1.7 Watts of power each drive

[Iron Condor]

And how is this power produced. I'm going to guess what is happening is that it comes up and warms up till it's core temperature is at the ambient surface temperature. Then it drops like a rock, and uses the heat differential between the core and the cold water to drive some thermo electric engine in reverse. perhaps they toss in some phase change material to extend the thermal capacity.

or is it something different?

Why not ask the people who built it? From http://solo-trec.jpl.nasa.gov/SOLO-TREC/ :

Special Phase Change Materials (PCMs) on-board the SOLO-TREC expand about 13% when heated above 10 degree Celsius and then correspondingly contract when cooled below 10 degree Celsius. This expansion/contraction produces a high pressure oil that can be collected and periodically released to drive a hydraulic motor for electricity generation and battery recharging. Since its deployment, SOLO-TREC has been making 3~4 dives per day between the surface and 500 meters depth, producing about 1.6 Watt-hours of power each dive to operate the on-board sensors, GPS receiver and communication device.

I'd like to add that JPL is of course the place to go to if you need to run gizmos for a long time on almost-no-energy input, reliably, in rather hostile environments. I mean - the Voyagers are still sending data home, 30+ years later , 100+ AU away and with a transmitter not much better than a modern cell phone...