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Robotics Science

Submersible Glider Powered By Thermal Changes 72

Posted by kdawson
from the kicking-the-battery-habit dept.
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."
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Submersible Glider Powered By Thermal Changes

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  • ...to counter the melting ice-caps.
    • by RuBLed (995686) on Tuesday February 12, 2008 @06:33AM (#22390014)
      That would be misinterpreted by the whales as an act of war...
      • by SQLGuru (980662)

        That would be misinterpreted by the whales as an act of war...
        The whales? Screw them, I'd be more worried about the friggin sharks.....with lasers!

        Layne
    • by MancunianMaskMan (701642) on Tuesday February 12, 2008 @06:56AM (#22390132)
      and it works brilliantly. Mind, it's not a submersible so it's not quite so cool. it's just a device [greenhousemegastore.com] that opens the window in my greenhouse so that the tomatoes don't get too hot in the summer!
    • by CarpetShark (865376) on Tuesday February 12, 2008 @09:30AM (#22391016)

      They should send a thousand of them to antarctica...to counter the melting ice-caps.


      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.
      • Re: (Score:2, Informative)

        by jim.hansson (1181963)

        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.
        NO, wrong, transform maybe, but depletes totally wrong
        • For all intents and purposes, it's depleted, if we can't put it back the way we found it, as quickly as we take away.
      • Do you have any idea just how BIG the oceans are and how much energy you need to remove to change the temerature by even a measurable amount?

        Even the global warming argument is based on a change of under 1 degree and is far from settled.

      • by Dutch Gun (899105)

        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.

        Technically speaking, you're correct, but talking of "depleting" wind, solar, or thermal power is not really an issue. These forms of energy are already depleting (wind is essentially another form of solar power, if you get right down to it). Both the earth and sun are radiating an unbelievable amount of energy, whether we collect it or not. Depletion is really only an issue, practically speaking, when it comes to natural resources used to generate power. As such, it only makes sense regarding combusti

      • by MrKaos (858439)

        Of course, "green" doesn't mean much, but energy is never free, and taking it from an ecosystem is always going to have consequences.

        The problem is that currently we are using solar energy from the past stored in the form of coal and oil. Essentially duplicating those pre-historic conditions, when the atmosphere was more carbon rich, into the present.

        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.

        We alr

  • by Dutch Gun (899105) on Tuesday February 12, 2008 @06:29AM (#22389994)
    Call me crazy, but I thought I remembered seeing something like this on the Discovery Channel (or somewhere on cable) a year or two ago... It's a pretty clever device, using the up and down motion to propel itself forward through the water for a reduced energy expenditure. Still, I'll bet they have a ways to go before these things can safely navigate the real hazards of long-term ocean research (I wish the article had working links to more info). Power consumption is a big part of that, but I'd imagine there's a lot of other stuff that can go wrong. The ocean is a pretty unforgiving environment for machines of any sort.
  • TFA does not mention whether it stores energy in 'thermal' form itself or uses the thermal waves to get energy and store in some other form, later case being most probable.
    • Uh.. the summary mentions that the heat causes wax to expand, so I'd have thought the article does the same. But yes it means that the energy is stored as pressure rather than storing the heat (which I'd think would be grossly inefficient).

      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

  • "The torpedo-shaped glider moves through the ocean by changing its buoyancy to dive and surface, unlike motorized, propeller-driven undersea vehicles"

    Last I checked submarines had air tanks for buoyancy control, and newer subs are not motorized, but nuclear-powered. Something change in the past few hours while I was sleeping?
    • Re:Wait... what? (Score:4, Informative)

      by MichaelSmith (789609) on Tuesday February 12, 2008 @06:46AM (#22390078) Homepage Journal

      Last I checked submarines had air tanks for buoyancy control, and newer subs are not motorized, but nuclear-powered. Something change in the past few hours while I was sleeping?

      Submarines don't use changes in depth to push them horizontally. This device is a bit like a sailplane.

    • Re: (Score:3, Interesting)

      by arivanov (12034)
      It is spelled GLIDER. G L I D E R

      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 s
      • It is spelled GLIDER. G L I D E R

        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.

        That would only work for limited dives; extended dives would be heavily dependent on your batteries and their ability to charge fast enough for your time on the water. Also, forget about any black-ops with such a design - for that you need to be under water as much as possible.

        TFA's design is pretty cool and would work even for extended dives. Since it doesn't require surfacing black-ops are also possible. It could probably reach deeper depths, and longer periods at deeper depths would be a given.

        Tha

        • So, let me get this straight, I remove the propellers that use energy and give the sub maneuverability and I use less energy? Brilliant concept, like a car that only uses a small battery to run the stereo but has no engine to waste gasoline. I just let the traffic push it along. I think I take a solar powered version that charges during the day and dives at night.
    • Re: (Score:2, Insightful)

      by don depresor (1152631)
      and newer subs are not motorized, but nuclear-powered. Excuse me but what do you think a nuclear reactor and a turbine are? If they had 100 guys pulling a lever that moved the propeller, then you could say that they aren't motorized ( and you could argue that they have an human motor anyway...). But saying that a nuclear sub isn't motorized...
    • Re: (Score:3, Insightful)

      by Simon Brooke (45012)

      "The torpedo-shaped glider moves through the ocean by changing its buoyancy to dive and surface, unlike motorized, propeller-driven undersea vehicles"

      Last I checked submarines had air tanks for buoyancy control, and newer subs are not motorized, but nuclear-powered. Something change in the past few hours while I was sleeping?

      And those 'newer subs' use a nuclear reactor to power - guess what? - a motor.

      There was a time when the average slashdot user had more than two braincells to rub together, but that time seems sadly past.

    • Re:Wait... what? (Score:5, Informative)

      by hcdejong (561314) <hobbes&xmsnet,nl> on Tuesday February 12, 2008 @08:21AM (#22390554)
      Last I checked submarines had air tanks for buoyancy control

      The air tanks are used mainly used to switch between surface and submerged modes, for trimming (keeping the sub horizontal), and to compensate for changes in water density. Because the amount of lift generated by a body does not change much with its depth, the air tanks cannot provide fine control of your diving depth. Also, a naval sub prefers not to use the air tanks once submerged, because venting air leaves a trail on the surface.
      For fine depth control, a sub uses its diveplanes: wing-like surfaces that provide lift (positive or negative) as long as the sub keeps its speed above a minimum.

      In effect, this glider reverses the process: changes in buoyancy are used to generate an upwards/downwards force, which is converted by the wings into forward motion.

      newer subs are not motorized, but nuclear-powered.

      You mean some newer subs are nuclear-powered. Conventional-powered submarines are still being built today. Often, in addition to the traditional diesel engines, an air-independent propulsion system is installed, either a Stirling engine or a set of fuel cells.
  • Things like these make the world sit up and realize that geeks and nerds have so much to contribute to society. Leave us to our pirated warez - we gave you teh Thermal Sub!
    • Just sayin'...

      -jcr
      • Re: (Score:3, Insightful)

        by MichaelSmith (789609)
        I can't see it working well in shallow waters. I don't think it would have much scope for navigation either, as it spends most of its time at depth away from GPS signals.

        For a drug mule you want something you can deploy and collect at a precise location on a beach, which for me, means a solar powered UAV which will sit just below the surface. Not that I have tried to build any such thing of course.

        Human drug mules are cheaper anyway.
        • by jcr (53032)
          I can't see it working well in shallow waters.

          I'd say it depends on the temperature gradient more than the depth. Even 50' lakes can have a pretty significant temperature difference from the surface to the bottom.

          -jcr
        • Re: (Score:2, Insightful)

          by don depresor (1152631)
          You know that nuclear subs have been traveling underwater for years before the existence of GPS tech, right?

          You have things like inertial systems, the old magnetic compass, sonars that help you by telling you the features of the sea bottom (you know like the old age when you looked for a landmark you knew and used it to locate yourself) and other things...
      • Re: (Score:1, Offtopic)

        *fingers crossed*
      • by merreborn (853723)

        Sounds like the perfect drug-smuggling device.
        It has a horizontal velocity of under 1 mph. I'd say that's a pretty major downside.
        • by jcr (53032)
          That may not matter, if you have a steady supply. The win would be that detection would be difficult due to the size, and interception at sea wouldn't risk the capture of the smugglers.

          -jcr
  • Built by the Webb Research Corporation in Falmouth, Mass., the new submersible has successfully traveled back and forth between two of the U.S. Virgin Islands, St. Thomas and St. Croix, more than 20 times. WHOI researchers plan to use the data gathered by the craft to study ocean currents in the area.
    Since when is something that physically exists and has been tested in the field vaporware?
  • first post?
    reminds me of Carl Sagan's fantasies about creatures on Jupiter... perhaps that inspired its conception
  • by z0idberg (888892) on Tuesday February 12, 2008 @07:11AM (#22390198)
    I know, I was shocked too, but the vaporware tag is wrong.

    They have had one working that has traveled 1400 kms so far since launch in December. Better article here
    http://www.cbc.ca/technology/story/2008/02/08/tech-glider-undersea.html [www.cbc.ca]
  • by WallyDrinkBeer (1136165) on Tuesday February 12, 2008 @07:24AM (#22390260)
    They've been testing it by cutting some cables, right?
  • by Anonymous Coward
    ...and that perpetual motion machines are bunk; but humor me.

    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
    • Could someone show me why you couldn't use this method of adjusting boyancy to get more energy out than you put in?

      First law of thermodynamics. The system you describe might work (probably very inefficiently) but it would not be getting more energy out than is put in. Every trip up and down would make the temperature of the ocean slightly more uniform; that's the energy loss to balance the energy being created.

      • Re: (Score:3, Informative)

        by zippthorne (748122)
        No, the energy in that plan doesn't come from the sea temp, it comes from the ballast. The thing you're depleting is the available buoyancy material, whether it be helium, air, or oil.

        For a closed-circuit buoyancy engine, you have to physically pump the buoyancy material around to get your change in density. This pumping is against whatever the ambient pressure is, so the deeper you allow it to drop, the more force you have to pump against to get your buoyancy back and return to the surface.

        Since you have
  • ...I used to have a sub that was powered by baking soda.
  • by Kupfernigk (1190345) on Tuesday February 12, 2008 @07:55AM (#22390436)
    "Scientists have invented the Prius of ocean-going submersibles - a new "green" robotic glider that runs on energy absorbed from the heat of the sea, rather than batteries."

    Scientists research, they discover, they do not invent. Engineers invent. Doesn't anybody in journalism know the difference between a scientist and an engineer? Also, the Prius is actually a bit like a conventional submarine - IC engine charges the batteries - and is therefore (from a marine engineering perspective) very old tech dating from before WW2. This on the other hand is seriously clever. In fact, it's like powering your car off a massive array of engine thermostats (which rely on wax as the operating means.) So a better lead in would be "Engineers have developed an energy efficient vehicle which is nothing whatever like a Prius - it uses temperature gradients in the sea to power itself."

    Perhaps Microsoft deserves to take over Yahoo.

    • by gardyloo (512791)
      Wow. So if I, as a "scientist", do any research, and in the course of that research need to invent something new -- a new measurement process, a lens holder, some clever demodulation circuit -- that means that I am not a scientist? I am an engineer?

            Engineers research, discover, and do _science_. Scientists engineer.
    • by merreborn (853723)

      Irritating first line of article... Perhaps Microsoft deserves to take over Yahoo.

      Yahoo! News rarely if ever posts anything written by Yahoo! employees. If they do have anyone writing exclusively for Yahoo! News, I've never seen it. In this case, the source is clearly identified by the logo that links to livescience.com and the tag at the top:

      Clara Moskowitz
      LiveScience Staff Writer
      SPACE.com

      So maybe Microsoft "deserves" to take over LiveScience.com...

    • Re: (Score:3, Insightful)

      by xPsi (851544) *

      Scientists research, they discover, they do not invent. Engineers invent. Doesn't anybody in journalism know the difference between a scientist and an engineer?
      I'm guessing since you just invented that distinction you are an engineer then? Seriously, I know plenty of scientists and engineers who do a healthy mix of research, discovery, and invention. Science journalism may have other problems, but I don't think this is one of them.
  • Rather, gliders [wikipedia.org] travel in virtue of the laws of reality alone. And at a speed of c/4.
  • Er, um, there's quite a few problems with this concept:
    • The efficiency is very low. Whatever the temperature difference is between the inside and outside of the sub in degrees C, divide that by 273, that's the maximum possible efficiency. If you wait forever for the heat to transfer. And assuming there is a difference to exploit.
    • Your typical sub has like 10 to 80 thousand horsepower. This sub, on a good day, might do 2% of that. Not exactly a barn-burner. And not even enough to run the lights and ai
    • Re: (Score:3, Insightful)

      by chuckymonkey (1059244)
      They never said that it had to carry people, and I bet it's a great research vessel since they have one working as a previous poster already said. Since it rides thermal currents in the ocean I think that you could put a GPS tracker in it and find some very good data about changing ocean currents, not to mention the vast amounts of other data you could gather with something like this that doesn't really need to refuel or resupply.
    • Re: (Score:2, Funny)

      by rholland356 (466635)

      Your typical sub has like 10 to 80 thousand horsepower. This sub, on a good day, might do 2% of that. Not exactly a barn-burner. And not even enough to run the lights and air-conditioners.

      True that!

      But given this is a robotic submersible, why does it need air conditioners and lights?
      • >But given this is a robotic submersible, why does it need air conditioners and lights?

        But it still needs to be able to move around. If it gets into a large area of homogenous water, like the Gulf Stream, what's it gonna do? Even in a perfect environment with steep thermal contrasts, I don't think it can buoyancy-glide it's way out of even a minor current. In the Gulf Stream, it's gonna flounder.

        • >But given this is a robotic submersible, why does it need air conditioners and lights?
          But it still needs to be able to move around. If it gets into a large area of homogenous water, like the Gulf Stream, what's it gonna do? Even in a perfect environment with steep thermal contrasts, I don't think it can buoyancy-glide it's way out of even a minor current. In the Gulf Stream, it's gonna flounder.

          Egads! Are you saying this device was engineered without consideration for usage? What leads you to this concl

  • by Anonymous Coward
    Its an interesting invention that will be great for near-surface work, but I guess it will not be a whole lot of use for deep exploration since temperatures remain pretty constant in deep ocean and if anything tends to get slightly colder with depth. But given its a hybrid perhaps you can burn the battery on the way down and use temperature increase on the way up :-)
    Still and interesting piece of equipment. Research veseel time is very, very expensive, so if the cost of creating an autonomous vehicle coudl
  • I can't see how modern day subs would have ANY interest in this. Seriously. You would have to modulate your path based on water temperature, and baby-jesus forbid, you are forced to transverse water the same temperature for a few months. This is useless technology unless WWIII starts tomorrow.
    • Re: (Score:3, Informative)

      by esocid (946821)

      I can't see how modern day subs would have ANY interest in this. Seriously. You would have to modulate your path based on water temperature, and baby-jesus forbid, you are forced to transverse water the same temperature for a few months. This is useless technology unless WWIII starts tomorrow.

      You seem to be missing the point, or didn't RTFA. This is a science vessel that uses a hybrid battery/thermal powered propulsion and electronic system. This allows the research vessel to remain submerged longer than no

  • Here's an article written in 2005 about these things: Underwater Robot to Re-Cross Gulf Stream [slashdot.org]
  • Politicians will claim prior art based on the fact that it's powered by a series of tubes.
  • I saw this more than 5 years ago on Discovery Channel.
  • Submersible CowboyNeal Powered by Linux Strikes at Soviet Russia.

    AH! MOTHERLAND!

    (vending from work)
  • The inventor David E. H. Jones, better known as Daedalus [wikipedia.org], described a very similar underwater glider in one of his columns. From memory, his version exploited a liquid that changed volume with temperature, rather than a wax (and the temperature-volume relationship was in the opposite direction).

    The column is included in the compilation "The Further Inventions of Daedalus" published in 1999. I think an early prototype of the wax-based mechanism (apparently an independent, though later, invention) had alre

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