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High-Tech Electro-Defroster 109

Posted by Zonk from the you-can't-get-rid-of-ice-fast-enough dept.
DahBaker writes to mention a News.com story about an ingenious way to de-ice a surface. From the article: "Dartmouth College engineering professor Victor Petrenko, not to be confused with one of the Champions on Ice, has devised a way to use a burst of electricity to remove ice caked on walls or windows. For surfaces coated with a special film, the jolt gets rid of ice in less than a second, far less time than it takes to hack at it with an ice scraper. While drivers might find easy-cleaning windshields convenient, the technology--called thin-film pulse electrothermal de-icing, or PETD--could have significant economic impact if widely deployed. It could, for example, cut the costs of repairing power lines downed by ice storms and keep plane windshields frost-free, decreasing fuel consumption."
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High-Tech Electro-Defroster

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  • Not just plane windshields (Score:5, Insightful)

    by MadEE ( 784327 ) on Saturday April 15, 2006 @09:15PM (#15136175)
    Assuming the material is durable enough it would be great on the flying surfaces too preventing icing which adds considerable weight and changes the aerodynamics of the plane. This would probably be far lighter then current solutions for this.

    • Re:Not just plane windshields (Score:5, Insightful)

      by Maxwell'sSilverLART ( 596756 ) on Saturday April 15, 2006 @09:36PM (#15136354) Homepage

      Assuming the material is durable enough it would be great on the flying surfaces too preventing icing which adds considerable weight and changes the aerodynamics of the plane. This would probably be far lighter then current solutions for this.

      Actually, this was my first thought too, but after reading the article, I'm not sure how much use it would be in aviation. As you correctly point out, the big problem with ice in aircraft isn't the windshield, but airframe icing (wings and tail); ice (or even frost) changes the shape of the airfoil, destroying the lifting capabilities of the surfaces.

      With a small panel, like a windshield, the power problem is manageable, but the leading edge of an airliner's wing is several hundred square feet (even a relatively small 737 has a wingspan of over a hundred feet for the later models, and you need to go at least a foot or two back on both top and bottom). Even assuming we only work on the leading edge, that's a hell of a lot of surface, and thus a lot of power. In reality, jet aircraft use hot wings, heated by bleed air from the turbines, and they heat the water on the leading edges enough that it stays liquid all the way to the trailing edge--these systems are more correctly called "anti-icing" than "de-icing."

      Smaller aircraft do use de-icing systems, in the form of pneumatic boots. With such systems, ice is allowed to accumulate until it reaches sufficient thickness to be thoroughly broken by inflating the boots, causing it to crack and fall off (deploying the boots early can result in the ice simply forming around the shape of the inflated boots, rather than their deflated shape, rendering the boots ineffective). I'd be interested to see whether this system suffers from a similar problem, or if it is effective against even trace buildups.

      The problem with it in light aircraft, though, is that such aircraft tend to have very low power budgets--there's not much surplus energy around. If there were, they'd use anti-icing systems, but intermittently shedding accumulated ice is very energy-efficient, especially when compared to energetic ice prevention (some aircraft carry alcohol anti-icing solution, which is excreted through "weeping wings" to forestall ice formation, but such systems are limited in the protection they can offer, both in severity and duration of icing conditions). Thermal anti-icing is cost-prohibitive, and electrical systems in light aircraft tend to be adequate, but with little overhead--while this system is more efficient than (presumably electrical) heating, it still may not be efficient enough. I'd also be interested to see what kind of electrical and magnetic noise this system might generate, though I'm sure that's been considered.

      All in all, this sounds like a neat idea, but I'm not sure it's going to find its market in aviation.

      • When I was in school, during one of the ASME meetings we had a presentation of a device to remove the ice from the wings. The plan was to have a series of these plates on the leading edge of the plane. during normal flight they would be inlayed into the wing and be aerodynamic. If you were in an icing condition you would start a trickle charge a bank of compactors. Then once the charge was built up a series of panels would "pop" pushing the ice off the wing. Then the caps would recharge and a second series
        • When I was at Cessna, working in the Experimental department, we tested just such a system. That was in 1985 or 1986. One major issue was that the interference with avionics was quite unacceptable, another was that the manufacturing cost was a lot more than the pneumatically inflated de-icing boots that were the status quo. It was quite fun to hold a penny near the leading edge and have it disappear, then hear it hit the wall on the other side of the hangar. Oh, yeah. That reminds me. Metal fatigue of th
      • The problem with it in light aircraft, though, is that such aircraft tend to have very low power budgets--there's not much surplus energy around. If there were, they'd use anti-icing systems, but intermittently shedding accumulated ice is very energy-efficient, especially when compared to energetic ice prevention (some aircraft carry alcohol anti-icing solution, which is excreted through "weeping wings" to forestall ice formation, but such systems are limited in the protection they can offer, both in severi

      • Re:Not just plane windshields (Score:4, Informative)

        by aibrahim ( 59031 ) <slashmail@NoSpaM.zenera.com> on Saturday April 15, 2006 @10:14PM (#15136514) Homepage Journal
        Maybe instead of "thinking" about the issue you should have checked out the company site where they have a video of ice being removed from an airfoil in a wind tunnel [iceengineering.com].

        That seemed like a fairly conclusive demonstration of the practicality of this process for that purpose.

        Now where is that damn pretty floral bonnet of mine...
        • You entirely missed the point of the GP, he didn't say that it wouldn't work, he said it'd need alot of power to cover the vastly larger area compared to that little aerofoil.
          • To support your claim, I note that the electrical leads leading to the test airfoil are really frickin' gigantic.

            But I also note that since the huge amounts of electricity only need to be delivered for a few seconds, that the power problem may be solved by

            1. dividing the airfoils into zones and de-icing them one at a time, and
            2. using capacitors or such to deliver the de-icing burst of electricity.
        • "Maybe instead of "thinking" about the issue you should have checked out the company site where they have a video of ice being removed from an airfoil in a wind tunnel. That seemed like a fairly conclusive demonstration of the practicality of this process for that purpose."

          Well, I'm admittedly "thinking" here, but how does a demonstration in a wind tunnel, where there is practically unlimited power available, demonstrate that such a system wouldn't overburden the plane's limited available power, the issue t

        • Maybe instead of "thinking" about the issue you should have checked out the company site where they have a video of ice being removed from an airfoil in a wind tunnel. That seemed like a fairly conclusive demonstration of the practicality of this process for that purpose.

          Maybe *you* should think rather than take at face value a few seconds of video. The video is of a model (a very small one at that) removing a one time accumulation (rather that the ongoing accumulation more typical of real aircraft). I

        • Maybe instead of "thinking" about the issue you should have checked out the company site where they have a video of ice being removed from an airfoil in a wind tunnel. That seemed like a fairly conclusive demonstration of the practicality of this process for that purpose.

          Looks like you completely missed his point.

          OBVIOUSLY it *could* work, the question is does it make sense to do it this way?

          If, for example, in that video they have to use as much power just to de-ice the wing as it would take to get
        • They all seem to say how hard it would be and how much power it would take. Do you know how much power is generated on an airplane? I don't, but I assume it is more than is generated by my car, and the car has do do this for the entire windshield, and possibly side windows and the rear-window. I'm pretty sure that the area to be defrosted on a plane's wings compared with the area of windows in a car is less than the ratio of power produced on a plane compared to that of a car. It looks like the de-icing
        • I can see that being an ass generates a pile of interest. It unfortunately doesn't engender any actual reasoning, just more "thinking." You people are intellectually lazy.

          Maybe I should try leading by example instead.

          The key is that the GP says power, but he is really talking about energy budgets. This thing needs power over a very short time. Not a huge pile of energy.

          How much energy... How about a calculation... oh dear is that sort of thing even possible on /. ? I'll try anyways. One caveat, whenever I t
          • I *insist* you double check before believing them.

            Done, and belief duly suspended. You're only off by a factor of a million, not too bad ... you should have been more suspicious when you gave the "less than a gram" figure. Multiplying the above two numbers gives 1.6 x 10^-3 m^3 = 1.6 x 10^6 mm^3. You need to pay for converting to millimeters in all three dimensions, not just 1. Which makes your figure 611 MegaJoules ... IANAAE, so I don't know if that's gonna be lying around or not, but it seems that
            • Well, thanks and you were right up to a point. Of course the point is rather moot, as I said before they have already flight tested the system. (Read Petrenko's page for what little there is.)

              Let's forget converting units and start again.

              541.2m^2*0.000003=0.0016236m^3

              The density of "solid water" at 0C is 915kg/m^3. Reference [simetric.co.uk]

              That means we have 1.485kg of solid water to turn to ice. That's 1.485kcal or 6.217kJ.

              As someone else pointed out I forgot heat of fusion [wikipedia.org]. That works out to ~497kJ. So, our total energy
          • Someone else already pointed out your obvious mistake in converting cubic meters to cubic millimeters, but that's not the only error...

            the total volume of water we are talking about over that vast area with the assumptions I have made is 1.6 mm^3. That is only about .146 grams of water.

            Isn't one of the supposed beauties of the metric system that you can deal with powers of 10? So how can it possibly be the case that 1.6 cubic millimeters is equivalent to .146 grams? That would be a factor of 10.9589.
            • I answered most of your issues in another post.

              The highlights-

              Powers of 10 ? Sure, but we are dealing with real materials. Real water has a density [simetric.co.uk] of 915kg/m^3 in solid form (aka ice) at 0C.

              As I said in the original post, we don't have to deice the entire wing, just the leading edges and a foot or two back. For a 747 the total is ~160m^2. So yeah- it is a huge overestimate in our workload.

              I did forget heat of fusion, so call it a car battery.

              Its reasonable to consider raising the temp only 1 degree for two
      • As you say, the power consumptions might not be the greatest.

        However think of this scenario. First a disclaimer, I am not in the aviation industry.

        What if this technique of removing ice from wings and other surfaces were used only while they were plugged in at the terminal. No need for chemicals or the engines to be running. The cost of electricity is far cheaper than a gallon of aviation fuel.
        • What if this technique of removing ice from wings and other surfaces were used only while they were plugged in at the terminal.

          That's not practical. The plane really needs the de-icing while in flight, because one of the major causes of aviation accidents is ice accumulation changing the shape and efficiency of the airfoil. Eventually the plane can no longer maintain altitude even at full power.

          And if it's not usable in flight, what does the airline get for the expense and added weight that the plane

          • I guess one of the points is, with the de-icing fluid carrys cost with it. One for the actual cost of the liquid, two the environmental clean up and three the man hours to do the work. And if I recall correctly, do they not actually sometimes do it multiple times before take off?

            So the question is, over the life of the plane, and the number of times it will be deiced, what is the cost benefit ratio. Do we save money even with the extra weight? Or is it still cheaper with the old method? That is somethi
            • Since no one else here is going to pipe in with airline experiance I may as well.

              When you de-ice/anti-ice an aircraft you spray it with a chemical. The De-ice is by all other virtue and for the sake of this argument just hot water. The Anti-ice is an expensive(and I mean EXPENSIVE) compound that resembles the slime left in the wake of ghostbuster's three with slimer(was that three? or two?). In order to provide an effective coating and bumping up the hold-over times(the time to get from the gate and into th
      • If you de-ice the wings of an aircraft flying at, say, 900 km/h, you are sending said ice toward the tail of the plane at same speed, repeating a recipe that caused, err, a major malfunction not so long ago at the occasion of a shuttle launch, aren't you? And that was not even ice, but just foam. Granted, the place will not have to suffer the penalty of a reintry into the atmosphere, but it is now understood that light debris flying fast can cause serious damage.
        • The foam was several inches think, waterlogged and frozen solid. The vehicle was traveling at great speed. The heavy, solid, ice-laden foam had a relatively long distance to decelerate before the leading edge of the wing hit it. And the damage was to the heat resistant tile; it was the failure of the tile that brought the aircraft to its end.

          In atmosphere - bound aircraft, the systems that shed ice are designed to shed it in small pieces at intervals that preclude it from building up too thick. Also, th
          • "And the damage was to the heat resistant tile; it was the failure of the tile that brought the aircraft to its end."

            I thought that, according to the findings of the review board, the damage was to one of the curved carbon-carbon panels that covered the leading edge of the wing, and not to the heat resistant tiles the cover the underside? Carbon-carbon composite is not the same thing as heat resistant ceramic tile.

      • Re:Not just plane windshields (Score:5, Informative)

        by darthwader ( 130012 ) on Saturday April 15, 2006 @10:43PM (#15136627) Homepage
        (deploying the boots early can result in the ice simply forming around the shape of the inflated boots, rather than their deflated shape, rendering the boots ineffective.)

        I really hope that no pilots are getting their flying advice from slashdot (just like no lawyers are getting legal advice here), but just in case: the latest research indicates that ice bridging is a myth, and you should use the boots as soon as you detect any icing, rather than waiting for build-up.

        http://www.aopa.org/pilot/features/inflight9910.ht ml [aopa.org], http://www.elliottaviation.com/wavelink/1999q1/wav art21.asp [elliottaviation.com] and http://www.faa.gov/library/manuals/examiners_inspe ctors/8400/fsat/media/fsat9818.doc [faa.gov] are good references.

        http://www.pilotfriend.com/safe/safety/icing_condi tions.htm [pilotfriend.com] is a great article about all sorts of aircraft de-icing and anti-icing methods.

      • The major problem with frost is not the change the shape of the airfoil; it disturbs the smooth airflow over the wing surface, causing turbulent separation, dramatically lowering lift.

        http://www.ultralighthomepage.com/STALL/stall.html [ultralighthomepage.com]
        http://www.av8n.com/how/htm/airfoils.html [av8n.com]

    • This would probably be far lighter THAN current solutions for this.

      You didn't think we self-important (for lack of better things to do) word Nazi pricks would go away just because of a six hour Slashdot meltdown, did you?
    • No more defrosting refrigerators! It would beat putting naked orphans with ice picks into my freezer, too. Er, not that I do that. The human remains in my garbage can were from some other pervert, officer...Not me.

  • cheap solar power (Score:1, Interesting)

    by dokebi ( 624663 )
    from the article:
    "We built a solar cell made of ice," he recalled. "While it is not as efficient as a silicon solar cell, it costs a penny a square mile."

    Solar panel that uses ice! This could be very cool for people in colder climates.
    • So lessee, if I've got this right I'll be able to heat my house in the winter by turning my patio into a skating rink with super bonded ice and when it gets too warm to maintain it simply reverse the polarity and zap it clean.

      I think I might be willing to sign up for that.

      I wonder how small you could make ice semiconductors.

      "Yeah, the server's down. The CPU, ummmmmmmmm, 'melted down' when it overheated to 1C."

      Maybe that's a better idea for Greenland than Brazil.

      KFG
    • Depending on the efficiency, this might work on Mars. Particurly, if it is easy to construct.
    • You insensitive clod - think about the coming global warming.

      You can't use the ice for making electricity - I need it for my drink!

    • Marvellous. Just don't use it for heating, eh?

      "Honey, what happened to the solar panel..?"

    • Solar panel that uses ice! This could be very cool for people in colder climates.

      Yeah - and ray nagin will just bitch all over the place that nobody's takin' the tech down south to help him rebuild his New Orleans-ian utopia.

  • It could be more useful on the wings. Keeping a plane in the air might be important too.
  • Has anyone seen the video demonstrating the technology? Yeah, they can remove a very thick layer of ice or snow, but I'm pretty sure it would be much harder with a very thin layer, on a surface that isn't oriented at 90 degrees.
  • I'd love to see the car version chargable by cranking the charger inside. Same energy efficiency, same exercise program, but much more comfortable.
  • The technology essentially takes advantages of the inherent properties of ice. Ice, it turns out, is a semiconductor, meaning that it conducts an electrical charge under certain circumstances.

    This appears okay so far, but as in any popular writing about a technical or scientific subject, use of such words as "under certain circumstances" is excessively vague. One can only hope that a later sentence clears this up. But that doesn't happen here.

    Unlike silicon, which conducts negatively charged electrons, ice
    • So the article is that the proton is the charge carrier in ice conduction?

      should read:

      So the article is saying that the proton is the charge carrier in ice conduction?
    • The BS detector is ringing -- fact free news article, company website with no information, and no products to buy. Sounds like a stock swindle, to be blatantly impolite about it. A few questions that come to mind, that aren't addressed anywhere; 1) As mentioned, proton conduction, instead of electrons? Huh? Is there some electrolysis going on? If so, why is it not mentioned? 2) This talk of ice being a semiconductor -- OK perhaps, but then if you put a film on a surface, then cover it with ice, then '
    • Well, this New Scientist article [newscientist.com] from 2002 is also about Victor Petrenko, and goes into a little more depth.

      Apparently, it is is the protons which are the majority charge carrier. If you remember your high school chemistry, there exists a small amount of hydrogen and hydroxl ions even in water with a pH of 7. Presumably, ice, which is a crystalline version of water, also has a small concentration of hydrogen and hydroxyl ions. According to the article, the free hydrogen ions (a.k.a. protons) travel
      • If it is so, should we presume that ice bonds with greater force to conductive and strong dielectric (and/or negative electric charged) materials' surfaces then to neutral/weak dielectric ones? Liquid water beeing both conductive (when carrying ions of other substances) and strong dielectric must be quite attracted to ice crystals - so presence of icy surface in a room should decrease humidity abruptly. I guess that was quite obvious, ha?. OTOH, there is something that isn't so obvious and should be yet det
    • Does the author (or the person who tried to explain it to him) mean that ice uses holes as the charge carrier just like P-type semiconductor, and he just messed it up/reinterpreted it as protons?

      The holes are protons (or at least, they could be. I need to find a decent article on the process to see: let's just assume it's really the hydrogens are proving the effect, and not the oxygens, okay?). Holes [wikipedia.org] are just unfilled states in a valence band.

      If you imagine pure hydrogen, for instance, the valence bands are
    • What's so frustrating about these watered-down "popular science" type articles is it's impossible to know if I'm reading something that is truly new to me, or (as I always suspect and too often find) it turns out I already know more than the writer ever will.

      Seriously. Not infrequently, the summary contains all of the information in TFA! Is there some other source (preferably a single source) that reports on these kinds of developments in more depth?

  • High tech, how? (Score:3, Insightful)

    by evilviper ( 135110 ) on Saturday April 15, 2006 @11:26PM (#15136784) Journal
    I must be missing something... Maybe the article is just light on details, but I can't see how this is any more advanced than the rear window defroster standard in every car made in the past couple decades.

    Electricity turns to heat, and melts the ice. Yippie. In this instance it sounds like electricity is being applied directly to the ice, possibly making this slightly quicker and more effecient, but I don't see anything revolutionary here. I also can't see how this is any less obtrusive...
    • I doubt you read the article, but I'm pretty sure that your car's defrosters don't make any icy buildups slide off in large chunks instantly. Watch the video for flying ice action.
      • ...I'm pretty sure that your car's defrosters don't make any icy buildups slide off in large chunks instantly

        Yeah, and the 'icy buildups' on _my_ windshields don't appear to be pounds-heavy solid square blocks that look like they're only adhering to the glass because someone laid a piece of warm glass on an ice block in a freezer.

        A conformal, self-supporting coating of ice isn't going to drop off as prettily as his ice blocks do. Next winter: go sit in an iced-over car and start up the defroster. It d

      • I doubt you read the article,

        You're only completely wrong... I guess that's close enough.

        but I'm pretty sure that your car's defrosters don't make any icy buildups slide off in large chunks instantly.

        Sure they do. Give them a minute or so to warm up, and start driving.

        On an airplane windsheild, the air is going several hundred MPH, and would work infinitely better than on a car.

        Watch the video for flying ice action.

        I don't have Flash installed, and I have no intention of ever installing it again.

    • My exceptionally boring (yet I love it to bits) Ford Focus (3 years old) has loads of tiny heating elements built into the front windscreen. I press a button on the dashboard an in about 15 seconds it's melted whatever happened to be stuck to the windscreen. Well actually it's more like what described here, it melts the layer between the ice/snow and the glass, so as you drive or use the wipers it all just comes off in chunks.
      The only advantage I can see with this method is that it's a bit faster and I ass
    • This device works on a different principle than your rear defroster. In your car, you have actual heating elements that have electricity passed through them, which in turn give up their heat to the ice. The problem is, however, that the applied heat quickly conducts away from the ice-windshield interface and into the bulk. Heating the bulk ice does no good at all. We all know how high the heat capacity of ice and water is - it takes a ridiculous amount of heat energy to melt ice into water. In addition

  • Champions of the Ice (Score:4, Funny)

    by roman_mir ( 125474 ) on Sunday April 16, 2006 @01:17AM (#15137091) Homepage Journal
    Victor Petrenko, not to be confused with one of the Champions on Ice - If you put those two into the same room, hilarity and confusion are bound to ensue, since they seem to be the Ice Champion and the Anti Ice Champion, the Ying and the Yang. We must keep them as far away from each other as possible, or there could be an anti-matter equivalent explosion.
    • That comment would have been a lot cooler if you'd spelled 'Yin' right.
      • Wow. You seem to the correct speller, and he is the anti-correct speller. So by his logic, you two should also be kept far apart.

        There maybe some possibility that the fact that you both post on slashdot is enough to trigger a cascade overflow... or something, so one of you should leave.
  • Why not use it on roads for deicing? It gets rediculous in some parts of the country.
  • Could they use something like this on the outer tanks of the shuttle instead of foam?

    Breaking and removing this ice before it becomes a huge iceball could be double plus good.
    • The foam provides insulation. If you removed the foam you could prevent ice from forming, but your liquid o2 would heat up much more rapidly. Probably causing a different problem.

  • Forget the stuff about semiconductors (Score:3, Insightful)

    by Flying pig ( 925874 ) on Sunday April 16, 2006 @05:45AM (#15137572)
    For windshields, this just seems to be all over defrosting from the inside by a fast pulse, a fast version of what Ford have been doing for years. You still have to remove the ice mechanically before it refreezes, otherwise the sheet will just stay in place and, as the article says, bond even more tightly than before (I've noticed this with Ford windshields - if you don't complete the melt cycle for some reason, you can get very firmly bonded ice.) Plus, what's the world indium supply like? And what is the chance of cracking the windshiled due to thermal shock? Heating the outside to 2 degrees C while the inside is at -10 doesn't sound terribly smart.

    So I suspect that to commercialise this a lot of research will be needed. Changes to windshield composition and design. Changes to wiper design. Uprated batteries. It might actually be cheaper to fit one of those nice Kenlowe or Eberspacher heaters with mobile phone control so you can simply start the car heating ten minutes before you leave the house or the office. After all, no matter how well the pulse technology works, at the end of it you are sitting in a freezing cold car, even if you can now see through the windshield.

    • You still have to remove the ice mechanically before it refreezes,

      I see you've found the tragic flaw in their idea. If only there were some device that could "wipe" the windshield as you deiced it.

    • Nope, you misunderstand what the article does. It is NOT just a souped up version of the Car defroster.

      More specifically, it does not require mechanical removal of the ice.

      Car heaters heat the entire ice evenly. By the nature of the process, it takes a lot of heat, and most of that heat is first transmitted deep into the ice. The surface of the ice touching the glass is still cold and loosely attached to it, so you need to wipe it away.

      This process heats just a thin layer that normally is bonded to t

  • A few drawbacks to this idea:
    • Electrically heated windshields, propellers, etc... have been around for 70+ years.
    • Jet planes spend 95% of their flying time way above or below the icing levels.
    • Jet turbines have a virtually free and unlimited amount of hot air availbale for deicing.
    • It's not affordable to load down a plane with 100's of pounds of extra generators, batteries, and/or capacitors that are only needed in very rare and usally avoidable circumstances.
    • The planes that would need this the most, litt

    • Re:not new pricey answer to a nonexistent problem. (Score:4, Interesting)

      by necro81 ( 917438 ) on Sunday April 16, 2006 @04:18PM (#15139528) Journal
      Preface: I was a grad student at the Thayer School of Engineering, where Petrenko does this research. During a power electronics class, we learned about the workings of some of this technology, and some classmates of mine designed some of the HF electronics that are behind this.

      Electrically heated windshields, propellers, etc... have been around for 70+ years. Yes, but those devices have heating elements that conduct heat into the bulk ice. You don't want to spend all the energy needed to melt all of the ice, or even a sizeable portion of it, but rather melt just the ice that's adhered to the windshield or airfoil. This technology does that. It creates HF eddy currents in the ice at the ice-windshield interface, liquifying that thin layer almost instantly. The liquification happens quickly enough that very little heat is conducted away into the bulk, which means that you aren't wasting or losing much energy. What's more, the heat is applied directly to the ice - no heater elements needed. Instead of pumping XX watts of power into heater elements and waiting for enough ice to melt to easily be removed, you pump (let's say) 10 times the power for 1/1000 the time into just the ice that matters, then let gravity, airflow, and wiper blades take care of the rest. It is a far more efficient way to remove ice.

      Jet planes spend 95% of their flying time way above or below the icing levels. Unfortunately, the place where icing is most likely is also the place where it is most dangerous: during takeoff and landing. Just because it is not a continuous threat during the flight doesn't mean that it isn't still extremely dangerous.

      Jet turbines have a virtually free and unlimited amount of hot air availbale for deicing. The hot gasses need to be hot if they are to produce thrust. Were the gasses diverted through some complicated heat exchanger to melt ice from the airfoils of aircraft, the exit gasses wouldn't produce nearly as much thrust. Once again, this technology works only on the ice that is adhered to the surface, and so works very efficiently. Using hot gasses, like heater elements, inevitably has most of its heat conducted into the bulk, where it does little good.

      It's not affordable to load down a plane with 100's of pounds of extra generators, batteries, and/or capacitors that are only needed in very rare and usally avoidable circumstances. This is not additional equipment for an airplane, it is meant to replace the de-icing equipment that some already have. Consider the cost of applying thousands of gallons of chemical de-icing to aircraft wings on the ground, or the electrical equipment needed to generate the huge amount of electrical power that goes into heating elements. If anything, this technology would have less equipment associated with it than other methods, because it uses far less energy. The amount of energy that it takes to use this equipment, even over the entire leading edge of an aircraft's wing, it relatively small compared to the power needed to run everything else, or the tremendous power output of the engines. It makes use of high-frequency power electronics, which are much more compact and efficient than traditional power electronics. True, it isn't need all the time, but there is tons (literally, tons) of equipment in an airplane that is only used occassionally. They all serve a specific purpose. I will admit that it will be expensive technology at the beginning, especially for retrofits, but most new technology is. Airbags were initially only seen in high-end luxury cars, but eventually trickled down to lower models.

      The planes that would need this the most, little prop planes that can't climb above icing, are also the ones that can least afford the weight penalty of this deicing system. Adding even 150 pounds to a small plane can make it a non-viable flying machine. Once again, this is not additional equipment, it is meant to replace existing de-icing equipment on a plane.
  • Similar articles have been posted on slashdot about his work over the years.

    Here's one from 2002.
    http://science.slashdot.org/article.pl?sid=02/12/2 7/226221 [slashdot.org]

    There was another one from I believe 03 or 04. Talking about slip/grip tires and using pulses to defrost electrical lines.

    Cool stuff if it works.
  • Every winter, as I survey the masses of snow that have just thwumped down on our grounds and exterior stairs, I remember my implicit assumption that the phaser was initially developed as an ice and snow clearance tool---hit the right resonances all at once, and the stuff sublimes away, or maybe goes directly to a plasma.....

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Top Ten Things Overheard At The ANSI C Draft Committee Meetings: (10) Sorry, but that's too useful.

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