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Real World High-Temperature Superconductor Engine

Posted by timothy on from the now-for-the-hybrid-cars dept.

wes33 writes "An amazing technological achievement deploying high-temperature superconductors is reported in Space Daily. American Superconductor Corporation (nice scifi-ish name) has built a 5MW electric ship motor using high-temp. superconductor technology. The Queen Elizabeth's 44 MW engines weigh 400 tons each (and she has two); a single comparable HST motor (36.5 MW) will weigh 75 tons!"

44 comments

  1. what about the generators? by tmacc · · Score: 2, Interesting

    As far as i know, they use diesel generators to provide the power usually. Using HTS in the generator would/could provide a drastic improvement in the effciency, and would be a much more exciting development in my opinion.

  2. disappointing article... by nusratt · · Score: 3, Insightful

    ...says virtually nothing about the actual HTS technology, which seems to be the only really novel aspect of this equipment.

    1. Re:disappointing article... by tmacc · · Score: 5, Informative

      http://www.amsuper.com/products/htsWire/ Here is a link that has some good specs on the wire they use.

    2. Re:disappointing article... by grumpygrodyguy · · Score: 2, Insightful

      AMSC's first generation HTS wire, based on a multi-filamentary composite architecture, is capable of carrying over 140 times the

      power of copper wires of the same dimensions.

      Umm, not to go overboard here or anything, but isn't this like one of the most significant engineering breakthroughs in the last 100 years or so?

      How about a new microprocessor fab process using this material?

      --
      The government has a defect: it's potentially democratic. Corporations have no defect: they're pure tyrannies. -Chomsky
    3. Re:disappointing article... by jericho4.0 · · Score: 1
      Because the 'High Temperature' in HTS is a temperature of 77K/-196C. Still very cool, but not the everday-device changing tech we're waiting for.

      --
      "A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis
    4. Re:disappointing article... by grumpygrodyguy · · Score: 0, Troll

      Because the 'High Temperature' in HTS is a temperature of 77K/-196C. Still very cool, but not the everday-device changing tech we're waiting for.

      Ah ok, well that answers that.

      --
      The government has a defect: it's potentially democratic. Corporations have no defect: they're pure tyrannies. -Chomsky
  3. More Power? by the+darn · · Score: 2, Interesting

    Since they've made one that's comperable in power but much smaller in size, would it make sense to make one comparable in size and of much greater power as a replacement for use in existing vessels? Or are there other limiting factors in the amount of power that is useable in such circumstances?

    --
    Ceci n'est pas un post.
    1. Re:More Power? by tmacc · · Score: 2, Informative

      For retrofitting, you wouldn't want to put an engine of much greater power in there, it would destroy the other parts. It would be like putting an 800 hp engine in a car designed for an 180hp one.

    2. Re:More Power? by Timber_Z · · Score: 3, Interesting

      Thats note the point. The point is that is FAR more effient then current technologies. The exact implemention is trival. Every so often technology makes a huge jump in performance that has a major impact on an industray. (Like moving from Hand Saws to Chain Saws for lumber: for example) This looks like it might be one of those times.

    3. Re:More Power? by Cecil · · Score: 4, Insightful

      Or are there other limiting factors in the amount of power that is useable in such circumstances?

      For a boat? Sure, cavitation. Propeller blades can only spin so fast (that is, push a certain amount of fluid) before they begin to create destructive turbulence in the fluid that cripples their pushing power. The same basic problem exists in aviation, which is why propeller-engine planes can only go so fast regardless of how big and numerous the engines and blades are. Jet engines, rockets, or some other form of propulsion are needed to go any faster.

      --
      Random and weird software I've written.
    4. Re:More Power? by Deliveranc3 · · Score: 1

      Offtopic stop here:Their?, There? As in over there tracks? Dude I don't get it.

      Do you mean Their which is the same word whether it's refering to the popups or someone else who would be forced to look at popups

    5. Re:More Power? by jfdawes · · Score: 1

      He's pointing out the incredible lack of language skills evident in MSNs' marketing department.

      Two mych dependentf onne "fpell checker"

    6. Re:More Power? by Deliveranc3 · · Score: 1

      Good I thought he was pluging some form of MSN browser plugin, which I imagine would require using I.E.

    7. Re:More Power? by Cecil · · Score: 1

      You are exactly correct. I think it's ludicrous that large companies can make blatant blunders like improper use of 'there' and 'their' in promotional materials intended for general consumption. If you want to impress me with your marketing, that's the #1 way not to do it.

      Although I think I am getting tired of that sig. Perhaps it's time to change it.

      (For the people viewing this thread later on, the sig in question refers to an ad on Hotmail which reads: "Help stop spam and pop-ups in there tracks with MSN Premium".)

      --
      Random and weird software I've written.
  4. With proper care.... by hummassa · · Score: 1

    A neighbour of mine had a Chevette 84 (originally 1.4 gasoline 70cv) retrofitted with a turbo 4.2 GM engine with 350cv or so. Obviously he changed a lot of other stuff as well, like brakes, transmission, suspension, etc, but the point is that the engine fit under the hood (with some effort -- he had to make a larger air intake in the front and he also had to put the battery and some other stuff in the trunk), so he put it there. And it worked like a charm.

    --
    It's better to be the foot on the boot than the face on the pavement. ~~ tkx Kadin2048
  5. No, more efficiency. by the_twisted_pair · · Score: 4, Insightful

    It's all about efficiency, and therefore running cost. Optimum cruising speed is set by considerations of wave drag for a given hull - there's a sharp curve, whereby faster cruises become *incredibly* inefficient. Big marine diesels providing this motive effort are far and away the most efficient prime movers on the planet, because economies of scale and the singular nature of the task lends itself very well to such optimisation - which the owners take advantage of.

    The bottom line is that every single %age point gained represents a huge saving to the owners in fuel cost. If it can be done with a lighter/more efficient propulsion package, so much the better - that's extra cargo that's free to carry, but the prime incentive is fuel cost - you may not realise we're talking *thousands* of tons for oil bunkers on big ships...

    I'm not at all surprised that marine propulsion is the first major application of high-temp superconductors in this regard.

  6. Generators aren't critical... yet. by Engineer-Poet · · Score: 4, Informative
    The Navy doesn't like diesels because they're too noisy for vehicles which chase submarines. The alternative is a gas turbine, which spins fast enough that you can make an acceptably small and light alternator without going to extreme materials; only when you need to drive a low-speed propellor do you really need the high-current capabilities of superconductors.

    The technical explanation is that you can transfer a lot of power with a small, rapidly-varying magnetic field (like the itty-bitty toroid in your computer's power supply, running at 100 KHz instead of the 60 Hz power line frequency), but to transfer the same amount of power with a slowly-varying field needs a much bigger field, bigger currents and bigger losses. Superconductors get rid of the losses and can sustain bigger fields in a smaller package.

    --

    Sustainability and energy independence essay
    1. Re:Generators aren't critical... yet. by Euler · · Score: 3, Insightful

      After reading the arcticle, the reason why these motors can achieve higher density is because the thermal dissapation issues are reduced when you don't have DC losses in your coil windings.

      You are right as far as lower freqencies needing more core material. But, I can't see how superconductors would change that equation at all. Even if the superconductor carries more current, the magnetic material has the same basic flux energy storage capacity. Ships tend to use higher frequencies anyway, such as 400Hz, so frequency probably isn't the problem. In a propulsion system, the design engineers are probably allowed to choose any frequency they want. Also, superconductors don't eliminate all loses. Core losses are still going to be an issue unless the motor design is significantly different than anything seen before, or uses superconducting mu-metal.

      You can always make a slower, higher torque high-frequency direct-drive sync motor by adding more poles. But you can't make a low-freq motor faster. i.e. top speed for a 2-pole 60Hz sync motor is 3600 RPM.

      Also, from what I remember, superconductors tend to lose superconductivity in strong magnetic fields. Hopefully, they have worked around that problem.

    2. Re:Generators aren't critical... yet. by WindBourne · · Score: 1

      And in spite of the lovely description, it appears that somebody is interested in Boat HST generators

      --
      I prefer the "u" in honour as it seems to be missing these days.
    3. Re:Generators aren't critical... yet. by Thing+1 · · Score: 1
      the same basic flux [...] capacit[or]

      Yeah, I'll burn in hell... ;-)

      --
      I feel fantastic, and I'm still alive.
    4. Re:Generators aren't critical... yet. by Engineer-Poet · · Score: 1
      I can't see how superconductors would change that equation at all.
      Power/volume is proportional to dB/dt. The lower the frequency, the higher B(peak) has to be to get the same dB/dt. Superconductors can maintain a higher B field under the conditions (heat dissipation, etc.) of large motors, so you can get more power out of them.
      Even if the superconductor carries more current, the magnetic material has the same basic flux energy storage capacity.
      Superconductors let you run with air cores; even iron isn't much help once it has passed saturation. (The reason you use a core is to lower the resistance of the magnetic circuit and get a greater B field for a given amount of coil current. At saturation, that stops happening.)
      ... superconductors tend to lose superconductivity in strong magnetic fields.
      They do; IIRC it's called "quenching". You just design your motor not to run at such high field strengths that it's a problem. MRI designers have the same issues, and they've solved them.
      --

      Sustainability and energy independence essay
    5. Re:Generators aren't critical... yet. by Amiga+Lover · · Score: 1

      The Navy doesn't like diesels because they're too noisy for vehicles which chase submarines.

      But they're PISTONS. Imagine the ricing up you could do on this one. (yes, that's a 108,000 horsepower engine with cylinders you could fit a dozen or more people in)

      A set of four hundred 200w ground effect neons, a couple of (dozen) turbos and a blow off valve that can create more PSHHHHHHHH than your average small jet... and she'd be SLIK.

      or something

    6. Re:Generators aren't critical... yet. by Euler · · Score: 1

      good points, and they help to demonstrate the trade-offs in transitioning to superconductors. The main issue is that superconductivity isn't a slam dunk, and it doesn't equal 100% efficiency. I think the article was just too rosy saying how revolutionary superconductors will be. The diminising returns of 1% efficiency improvment (claimed in the article) and smaller motors on a large ship may not justify the high maintainance and design costs of a superconducting system. I'd like to see how much plumbing and equipment is needed to provide ongoing cryogenic cooling.

  7. what temp? by klossner · · Score: 4, Interesting

    The article is silent on exactly which temperature this high-temperature superconductor requires. Are we still at liquid-nitrogen temperatures or have we gone higher?

    1. Re:what temp? by SurG · · Score: 3, Informative

      The link to their website [amsuper.com], mentioned earlier, has some really nice technical papers. For one type of the wire they use some complicated compound with Tc =110 K. Didn't find Tc for the second type of wire (Y123). I'm pretty sure, however, that even if Tc is higher than 77 K, they still run it on 77 K, since other parameters like Ic should be better than around Tc. And nitrogent is pretty much standart cryoagent anyway. Their critical current for those wires looks pretty impressive (> 100 A )

    2. Re:what temp? by dbIII · · Score: 1
      high-temperature superconductor requires. Are we still at liquid-nitrogen temperatures
      We still are - high temperature refers to a long way above absolute zero, since superconductivity was originally seen close to that temperature. Liquid nitrogen is relatively easy to make, easy to transport and in most places is cheaper per litre than milk. Having an entire power grid cooled by the stuff would be a mammoth infrastructure task, but with an engine you just have a big tank of the stuff. On a large ship it wouldn't be that difficult to compress liquid nitrogen out of the air.

      What would be ideal would be a superconductive material that works to at least 50 Celcius, and can be worked like a ductile metal - but we can do a lot with what we have instead of just hoping for somethinhg better to be found.

    3. Re:what temp? by Hydrogenoid · · Score: 1

      According to that site http://www.amsuper.com/products/htsWire/ it is likely to be under 100K, and most info being given at 77K, sounds like liquid nitrogen cooling.

    4. Re:what temp? by merlin_jim · · Score: 2, Informative

      Why does everyone say with superconducting wire in the power grid that the cooling is the hard task?

      That's not it, it's raw current carrying capability. Superconductors break down at high currents. Cooling a superconducting wire isn't as hard as you might think.

      Superconductors conduct heat as well as electricity. The Newtonian description of the heat of a superconductor is the net average of all the temperature deltas it's exposed to integrated over the area of exposure. A superconducting wire is (in a non-relative universe) always the exact same temperature throughout.

      Make the wires thin (don't need thick wires if you're super conducting), they're probably brittle so you'll have to clad it in a fairly rigid material... and just make that material a pretty good insulator. With a thin enough wire you can have practically zero surface area. And your cladding will probably be cheaper than high tension cable. You'll have to bury it because superconductors have a catastrophic failure mode; if a high temperature event happens, the entire wire will stop superconducting immediately, and all that electricity in the wire converts to thermal/kinetic energy, as the electric field damping generates a huge magnetic field and basically turns the entire wire into a railgun pointed radially outwards.

      At both ends, have a heatsink of superconductor material embedded in liquid nitrogen. As long as any liquid nitrogen remains, the entire wire will be at the temperature of the liquid nitrogen. The only reason you need a heatsink is to spread out the area of contact so you don't boil the liquid nitrogen so fast that large air bubbles form on the surface of the heatsink.

      The more insulation you have the less liquid nitrogen you'll need on an ongoing basis to replenish the system. But compressing liquid nitrogen out of the air is a relatively cheap activity in terms of energy expenditure. Especially if you have superconducting wire to make the compressor out of. No reason not to just submerge it in the liquid nitrogen with the power distribution wires.

      Though you might want some of the motors to be a more traditional design... startup on a system like this is a bitch. The wire doesn't go superconducting all at once, there's a travelling wavefront that moves along it, speed dictated by the rate of heat conduction at the interface. In the case of a blackout, you'd have to have traditional compressors with backup generators (or just big power storage caps) in the mix just to get the whole system back online as quickly as possible, otherwise you're stuck waiting for the heat to travel through the system, building up reservoirs of liquid nitrogen and removing progressively more heat as each distribution station comes back online.

      --
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    5. Re:what temp? by bitingduck · · Score: 1

      At both ends, have a heatsink of superconductor material embedded in liquid nitrogen. As long as any liquid nitrogen remains, the entire wire will be at the temperature of the liquid nitrogen. The only reason you need a heatsink is to spread out the area of contact so you don't boil the liquid nitrogen so fast that large air bubbles form on the surface of the heatsink.

      Just cooling the ends isn't likely to work well, but cooling is still not a fatal problem. In a lot of applications, even conventional copper cables need to be cooled--they run oil through a hollow core and put copper on the outside. They have to maintain pumping stations, heat exchangers, etc. to do this anyway. If you replace it with HTSC material you need fewer cables for the same power.

      There are also apps in the power grid for superconducting materials besides transmission, and which are easier to get into. Energy storage, for high reliability systems is one, systems to keep different sub-grids in phase at the connections is another.

    6. Re:what temp? by merlin_jim · · Score: 1

      Just cooling the ends isn't likely to work well, but cooling is still not a fatal problem.

      Can you please elaborate? What problems do you see with this?

      --
      I am disrespectful to dirt! Can you see that I am serious?!
    7. Re:what temp? by jovlinger · · Score: 1

      It's not immediately clear to me why the propagation speed of heat in a wire (dist per deltadegree per time?) should go from very low in a non-supeconductor to speed of light when the same material is superconducting... after all, the electrical propagation speed isn't affected, is it?

      I'd much appreciate an intuitive description of why this is the case.

      thx

    8. Re:what temp? by merlin_jim · · Score: 1

      Heat is random kinetic energy. This energy can be transferred by electrons in a conductor, termed electric convective heat transfer, and this is why most good conductors of electricity are also good conductors of heat.

      I tried to google for references; some indicated that this was the case, while others specifically counter-indicated it! I don't know what to believe any more... one source specifically indicated that Cooper pairs interact poorly with their host material and this is the reason for poor heat conductivity... but HT superconductors aren't based on Cooper pairs. I couldn't find any real world studies of actual rate of heat transfer through HTS.

      Guess I'm gonna have to find my superconductors and USB ADC box for thermal probes and do some research on it...

      --
      I am disrespectful to dirt! Can you see that I am serious?!
    9. Re:what temp? by dbIII · · Score: 1
      That's not it, it's raw current carrying capability
      Not really a problem if you have enough of them and a big enough gap between them to handle magnetic feild limits. I remember reading out designs that got around this more than ten years ago.
      Make the wires thin
      One problem with the superconducting materials is you can't work them, so you can't extrude them as wires or like glass fibre, and you certainly can't melt the materials we have and expect them to solidify as anything that superconducts. The components are made by grinding a mix of chemicals up, firing it grinding it up again, putting the powder in a mould of the shape you want it to be and then firing it again. One thing that makes it possible to have a long line of superconductors is that a gap between components can be tolerated and superconductivity of electricity retained due to magnetic feilds bridging the gap. Since you effectively have a pipe full of brittle ceramic, it's not much of a deal to have an extra pipe full of liquid running nearby.

      I don't know enough about the current theories to know what will happen to the thermal conductivity - in the best case with rigid bars of the stuff you still have a gap every few metres and the enclosure may be conducting the heat, so the big heatsink idea may be less practical than you think, and may need closer spacing.

      No reason not to just submerge it in the liquid nitrogen with the power distribution wires.
      Liquid nitrogen conducts electricity. When you test resistance to see if your superconducting material works, you keep it dry but at liquid nitrogen temperatures.
    10. Re:what temp? by bitingduck · · Score: 1

      Conducted heat is proportional to the [(area of the conduction path)/(length of path)]*(Temp gradient along that path)

      For a long skinny wire you have heat leaking in through a large area (diameter*length) conduction path that's very short (a few cm from any outer insulation to the inner wire) and with a very large temperature gradient (300K to 77K along that short path). To conduct that heat out you have a small area (a few cm square), a very long length (hundreds of meters or even km) and a very small temperature gradient (maybe 80K or so might be acceptable at the hottest points, and 77K at the bath. Even with a vacuum and many layers reflective insulation to beat radiated heat, you aren't going to make a very long wire superconduct, and it's going to be a pain to maintain. It's a whole lot easier to make hollow cable and run LN2 through it (if you check out the AMSC web site, that's what they do).

      The current carrying capacity of HTSC materials is now high enough to be competitive with copper for a lot of applications. If you have a bunch of cables under a city and they're running at capacity and need to be replaced, you can get more capacity in the same space with HTSC cables, and probably save yourself a whole lot of digging.

    11. Re:what temp? by bitingduck · · Score: 1

      so you can't extrude them as wires or like glass fibre

      They mix them with silver to make them more ductile. They can be made to be bendable comparable to other large cables, but not bendable like little bitty computer cables. Some of the low temp superconducting materials are also very brittle (Nb3Sn) but people have managed to use them very effectively for high field magnets. At least some HTSC wires are made in much the same way as low temp superconducting wires, where they draw it into a long wire, cut it into shorter lengths, stuff those parallel into a tube, draw it out, rinse, repeat, and end up with a bunch of small conductors so there's a lot of surface area.

      Liquid nitrogen conducts electricity

      Not appreciably, and gold is an insulator compared to a superconductor-- some of the early low temp superconducting magnets were made using gold as an insulator. Once the material goes superconducting (not just low resistance, but really zero) even a very low resistance path is effectively insulating. It's pretty common to just dunk things directly into LN2 to measure their resistance at 77K.

    12. Re:what temp? by Suidae · · Score: 1

      Superconductors conduct heat as well as electricity. The Newtonian description of the heat of a superconductor is the net average of all the temperature deltas it's exposed to integrated over the area of exposure. A superconducting wire is (in a non-relative universe) always the exact same temperature throughout.

      If this is true (as noted in a child, sources seem to conflict), then there must be a critical figured for heat conduction too, else you could move enormous amounts of heat energy as easily as electrical power. If there was no limit it would be more effective to generate heat at one end of a very long, fine SC wire and use it to drive a boiler or other heat engine at the other end.

    13. Re:what temp? by merlin_jim · · Score: 1

      Wow. Great insight there. I had never considered that angle; you must be right.

      As to whether or not its true, on further research I found that some sources agree, some disagree, but noone seems to have any hard figures posted online either way. I'm considering ordering a labtech DSP and checking it out for myself.

      --
      I am disrespectful to dirt! Can you see that I am serious?!
    14. Re:what temp? by jovlinger · · Score: 1

      cool. please let me know if you come to any conclusions

  8. Yes, hull shape by leonbrooks · · Score: 2, Interesting
    are there other limiting factors in the amount of power that is useable in such circumstances?
    At a certain velocity dependent upon the shape, the hull changes from slicing through the water more towards trying to push against it, once you cross this knee, you need to add bucketloads of power for a very small improvement (basically, until you get your aquatic beastie to plane).

    Modulo propellor cavitation, hull collapse and other stuff which becomes dominant at those power levels, it would be quite a joy to see an ocean liner scudding friskily from wavetop to wavetop.
    --
    Got time? Spend some of it coding or testing
    1. Re:Yes, hull shape by Suidae · · Score: 1

      I've always wanted to see an oil-tanker sized ekranoplan type vehicle. The largest of the russian prototypes carried 100 tons, I wonder if it would scale up to 10,000 :)

  9. "High Temperature" by Mark+of+THE+CITY · · Score: 1

    But 77K is the boiling point of nitrogen at standard atmospheric pressures. Given that liquid N2 is fairly cheap, one should look for early-adopt motor apps and maybe low-loss electricity transmission.

    --
    The clearance system sounds logical. It is not. It is completely arbitrary. -- John Bolton
  10. But look at the details by Engineer-Poet · · Score: 1
    Yes, but can you imagine putting a piston through the head because of overspeed... at 120 RPM? (I know you're kidding, but I want to make a point.)

    That engine has a top speed of 102 RPM because it's direct drive. Direct drive eliminates the need for motor-generator sets and all the bulk, weight and cost people have been talking about above, but it also cuts the power output and increases the required size of the engine.

    Other marine diesels seem to be designed to run at 600-1000 RPM. An engine running at 6x the speed can move 6x the air and fuel per unit of displacement, and thus could be about 1/6 the size and weight for the same power. This becomes even more lopsided for gas turbines; an 85 MW GE gas turbine is a tiny fraction of the size of the diesel of the same power, and an even tinier fraction of the weight.

    --

    Sustainability and energy independence essay