High-Tech Electro-Defroster 109
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."
Re:Is it me.. (Score:5, Funny)
Re:Is it me.. (Score:2, Funny)
Re:Is it me.. (Score:2)
Same thing we do every April 15th, Pinky... try to get our taxes done on time. Not sure if I'd call it a celebration. I actually was reading the tax code as 'the player' rather than 'the payer' as I slogged through schedule D. Sure sign of AD&D growing up...
Re:Is it me.. (Score:1)
Re:Is it me.. (Score:1)
Ah yes... six readings and four psalms...
We can say "Alleluia" again.
Re:Is it me.. (Score:2, Funny)
Re:Is it me.. (Score:3, Insightful)
As for this article.. very cool. I need it on my car. bad.
Not just plane windshields (Score:5, Insightful)
Re:Not just plane windshields (Score:5, Insightful)
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.
Re:Not just plane windshields (Score:2, Interesting)
Re:Not just plane windshields (Score:2, Interesting)
Re:Not just plane windshields (Score:2)
Re:Not just plane windshields (Score:2, Interesting)
Re:Not just plane windshields (Score:4, Informative)
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...
Re:Not just plane windshields (Score:2)
Re:Not just plane windshields (Score:2)
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
Re:Not just plane windshields (Score:1)
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
Re:Not just plane windshields (Score:2)
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
Re:Not just plane windshields (Score:2)
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
Don't listen to other repliers (Score:2)
Re:Not just plane windshields (Score:3, Informative)
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
Re:Not just plane windshields (Score:2)
Done, and belief duly suspended. You're only off by a factor of a million, not too bad
Re:Not just plane windshields (Score:2)
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
Re:Not just plane windshields (Score:3, Informative)
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
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
Re:Not just plane windshields (Score:2)
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
Re:Not just plane windshields (Score:1)
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.
Re:Not just plane windshields (Score:1)
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
Re:Not just plane windshields (Score:2, Insightful)
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
Re:Not just plane windshields (Score:2, Insightful)
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
Re:Not just plane windshields (Score:1)
Re:Not just plane windshields (Score:1)
flying ice (Score:1)
Re:flying ice not foam (Score:1)
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
Re:flying ice not foam (Score:2)
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)
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.
Re:Not just plane windshields (Score:2)
http://www.ultralighthomepage.com/STALL/stall.htm
http://www.av8n.com/how/htm/airfoils.html [av8n.com]
Re:Not just plane windshields (Score:2)
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?
How about appliances? (Score:2)
Re:How about appliances? (Score:2)
Re:This can't be first.. (Score:1)
However, several of these top posts were all modded flamebait -- mine should be modded Dumb, but the other two were actually above-average for slashdot!
Well, whoever it is, let's just all hope that the good other mods burn their points to help us unfortunates who have been unfairly labeled as Flamebait -- and whoever that is, gets nuked from orbit and never mods again.
It's the only way to be
cheap solar power (Score:1, Interesting)
"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.
Re:cheap solar power (Score:1)
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
Mars? (Score:2)
Save the Ice! (Score:2)
You can't use the ice for making electricity - I need it for my drink!
Re:cheap solar power (Score:1)
"Honey, what happened to the solar panel..?"
Re:cheap solar power (Score:1)
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.
Sure, the windshields are more important. (Score:2, Insightful)
Re:Sure, the windshields are more important. (Score:2)
Re:Sure, the windshields are more important. (Score:1)
I am wondering what problems will have to be overcome, mostly the durability problem. How long will the product last?
It will boil down to an economics problem in the end. Continued improvements in materials will determine applications.
Re:Sure, the windshields are more important. (Score:1)
The video is not impressing... (Score:1)
Re:The video is not impressing... (Score:1)
Crank Invention (Score:2)
Re:Crank Invention (Score:2)
Get a clue before posting, Anonymous pampered Coward.
Does this quote from TFA sound like BS? (Score:2)
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
Short correction to text... (Score:2)
should read:
So the article is saying that the proton is the charge carrier in ice conduction?
Re:Yes It Sounds Like BS (Score:1)
Re:Does this quote from TFA sound like BS? (Score:3, Informative)
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
Re:Does this quote from TFA sound like BS? (Score:2)
Re:Does this quote from TFA sound like BS? (Score:2)
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
Re:Does this quote from TFA sound like BS? (Score:1)
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)
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...
Re:High tech, how? (Score:1)
Re:High tech, how? (Score:1)
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
Re:High tech, how? (Score:2)
You're only completely wrong... I guess that's close enough.
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.
I don't have Flash installed, and I have no intention of ever installing it again.
I'm with you on this (Score:2)
The only advantage I can see with this method is that it's a bit faster and I ass
Re:High tech, how? (Score:2)
Re:What about frost free freezer? (Score:2)
Champions of the Ice (Score:4, Funny)
Re:Champions of the Ice (Score:2)
Re:Champions of the Ice (Score:2)
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.
Road Deicing (Score:1)
Re:Road Deicing (Score:2)
Shuttle Foam (Score:1)
Breaking and removing this ice before it becomes a huge iceball could be double plus good.
Re:Shuttle Foam (Score:2)
Forget the stuff about semiconductors (Score:3, Insightful)
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.
Re:Forget the stuff about semiconductors (Score:1)
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.
Re:Forget the stuff about semiconductors (Score:2)
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
not new pricey answer to a nonexistent problem. (Score:2)
Re:not new pricey answer to a nonexistent problem. (Score:4, Interesting)
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.
Same story here in 2002 (Score:2)
Here's one from 2002.
http://science.slashdot.org/article.pl?sid=02/12/
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.
Winter: preparing us for the final frontier (Score:1)