“Green” robot self-propels through sea
Good thing they didn't paint a shark smile on the
front end.
Taking a page out of a science fiction story, researchers…have successfully flown the first environmentally powered robotic vehicle through the ocean. The new robotic “glider” harvests heat energy from the ocean to propel itself across thousands of kilometers of water.
In December 2007, a research team…launched a prototype “thermal glider” off the coast of St. Thomas. The vehicle has been traveling uninterrupted ever since, crisscrossing the 4,000-meter-deep Virgin Islands Basin between St. Thomas and St Croix more than 20 times…
The new thermal glider draws its energy for propulsion from the differences in temperature—thermal stratification—between warm surface waters and colder, deeper layers of the ocean. The heat content of the ocean warms wax-filled tubes inside the engine. The expansion of the warming wax converts heat to mechanical energy, which is stored and used to push oil from a bladder inside the vehicle’s hull to one outside, changing its buoyancy. Cooling of the wax at depth completes the cycle.
“We are tapping a virtually unlimited energy source for propulsion,” said Fratantoni. The computers, radio transmitters, and other electronics on the glider are powered by alkaline batteries, which are, for now, the principal limit on the length of operation.
I love the science; but, this critter surely could scare the Bejeebus out of an unsuspecting scuba diver off the Virgin Islands.
Posted: Sun - February 10, 2008 at 10:48 AM