Submersible Glider Powered By Thermal Changes 72
An anonymous reader writes about a new robot submersible that uses temperature differences in the sea to power operation for more than twice as long as previous, battery-dependent vehicles. "The torpedo-shaped glider moves through the ocean by changing its buoyancy to dive and surface, unlike motorized, propeller-driven undersea vehicles. To power its propulsion, the submersible gathers thermal energy from the ocean. When it moves from cooler water to warmer areas, internal tubes of wax are heated up and expand, pushing out the gas in surrounding tanks and increasing its pressure. The compressed gas stores potential energy, like a squeezed spring, that can be used to power the vehicle. To rise, oil is pushed from inside the vehicle to external bladders, thus increasing the glider's volume without changing its mass, making it less dense. The oil can be shifted inside to increase the density and sink the vehicle."
Is this new? Still, cool stuff... (Score:3, Interesting)
I've got it deployed against the greenhouse effect (Score:4, Interesting)
I know this is impossible... (Score:1, Interesting)
Could someone show me why you couldn't use this method of adjusting boyancy to get more energy out than you put in?
Let's say you have your sub which is neutrally boyant at the surface. You pump oil out of the bladders. The sub drops. When the sub gets to the bottom, you pump your oil back into the bladders. The sub rises once more.
And let's say the drop is used generate electicity, via magnets or coils the sub falls past.
Now... Does the energy required for pumping the oil always equal the amount of energy which is generated by passing the sub past the coils? It does require more energy to pump the oil into the badders when the sub is on the ocean floor, due to the increase in pressure, but it seems odd to think that the amount of energy required to simply blow up a balloon is the same as whatever energy you could extract from it's rise into the straosphere, and its subsequent plummet back to earth.
Re:Wait... what? (Score:3, Interesting)
On a more serious note gliding or "flying" under water as means of improving fuel efficiency and maneuvrability are not new. Research has been going on this since the 60-es. None of it has produced anything particularly spectacular.
Neat design, though there is a simpler way to do it. Put some solars on the glider, charge it on the surface, after that use the energy to compress the air used to expell the ballast tank. Sink. Reach target depth (gliding). Spew out ballast the same way a submarine does. Float up. Gliding. Sit on the surface while charging for another dive.
Trivial to do. No need for complex thermal stuff and you can probably survey half of the Pacific at a leasurely pace on one run until your batteries run out of charge cycles. This type of kit needs to float to the surface to transmit data back to base anyway, so why not do something productive in the meantime.
New problem, same root cause (Score:5, Interesting)
I assume you're getting at the same thing that I'm wondering... how much of an impact does this have on water temperature, currents, etc., if they're trying to call it "green"?
Of course, "green" doesn't mean much, but energy is never free, and taking it from an ecosystem is always going to have consequences.
In this case, we could try to use these, make them popular, and find out that they not only take heat energy from the oceans, but also change currents.
Likewise, we could try to cool the ice-caps somehow, but that wouldn't "counteract" what's happening with global warming; it would a more volatility to the system, with more extreme cold in one place battling more extreme heat elsewhere. The weather system is already too screwed up as it is without that.
And that's the REAL problem with this AND global warming: that we take things, on a massive scale, without any real respect for the damage it causes, or the slow processes that are needed to create what we take quickly. We can barely admit that we're doing damage, let alone facing the fact that the damage cannot be undone easily.
I'm not saying that we shouldn't use wind power, or solar power, or thermal power, or even combustion engines. BUT, we need to every bit of energy we take from the world -- in WHATEVER form -- depletes it, and that the only real solution is to cut back on how much we take.