Dispatches from District 48
Using a helicopter and a large tank of heated water to deice a windmill so it can continue to reduce fossil fuel use and global warming. (source)
I'm surprised they use hot water from a chopper. Would have thought they would have something like what they have in planes, either electric heat to the wing, or a weeping system with deicing fluid, or something else.
Spinning the darn thing would have broken the ice off the blades, the only reason why they're deicing them is likely due to the aerodynamic change causing the blade to not catch the wind correctly or not at all. What a waste.
The ice also ruins the dynamic balance of the blades if it doesn't break off evenly, which can be very damaging.
You're probably right about the decision in this case, but the WTC example has to be apocryphal. Just googling typical costs for today I come up with about 200W for lighting in a typical office and $0.10/ft for 20 gauge building wire. So leaving out a switch would save about $1 (5ft down to the switch and 5ft back up to the drop space). Assuming the switch itself and labor brings the total cost to $10, and an electricity price of $0.10/kWh, and ignoring the cost of more frequent bulb changes, then it only takes 500 hrs for the switch to pay for itself. Whatever the prices where back in the 70's, I'm pretty sure they weren't off from this estimate by a factor of several hundred.
So do insects and I imagine bird parts.
The fools are running the world
Where was the photo taken?
I expect that the costs of this de-icing are accounted as "Non-recurring maintenance", so it doesn't affect the reported efficiencies of wind power.
i am just guessing here, but the materials may be an issue. those huge windmill blades are made of carbon fiber. this makes them far harder to run channels in (and the extra weight of such things could be problematic) and may also preclude some forms of de-icer as it might affect the carbon. carbon is also a lousy conductor of heat, so running electric warming could be problematic as well.
Winter occurs therefore Global Warming is false. QED.
What a shame that we live in such a time that we can engineer something to rotate in the wind, but the minute that ice forms on it, it could break. If I owned that wind turbine and was told it would break because its out of balance from ice I would fire the contractor that built it.
Engineers can't change physics. Unless you're operating at very slow speeds with relatively low loads, it's very difficult to engineer something that will operate reliably in an unbalanced state for a long time. Creating a structure and bearings that could reliably deal with that would add a great deal of cost and weight to the final product, and it's an engineering and economic decision as to how fault tolerant the rotor should be, versus accepting a certain amount of downtime.
What is more feasible is preventing the ice from forming, or melting it before the buildup becomes debilitating, in which case there are a variety of technologies available from the aerospace industry, like heated blades and weeping wings and so on, but those may or may not be economically feasible. If the turbine is in North Dakota, it would be dumb not to have anti icing equipment, but if it's in Texas, it may be cheaper to accept a week of downtime every fifth year than to maintain the anti icing system over those five years.
The spinning blades can also fling 20lb shards of ice hundreds of yards. Not fun if you happen to live next door.
Exactly. Its just so dumb that these things are built in places where they can't be used for long periods of time. Sure I can spend $5,000/hr deicing the blades to use for only a few days before the next winter storm. I'd be amazed if these didn't fall down in an ice storm.
I don't remember the actual rotational speed of a wind turbine but its not particularly fast by most standards as the large blades are turning a relatively small gear (in comparison to the size of the blades) set hooked up to a generator. The problem isn't that it has ice on it, the turbine blades face something much more dangerous with strong winds, which is why they have brakes and are usually not in use in high winds. Ever see one spin out of control in a wind storm?. The problem with the ice is that they're a projectile and fall hazard, which is its own moral responsibility, do I really want to pay for somebody's broken roof and windows? Nah. So why bother letting what clearly looks like is a several inches of snow and ice freeze on this, its a waste of money build this in a place where it can't be used 3 or more months of the year because the weather conditions preclude it.
Yeah, I mean, why is he picking on windmills? Doesn't Warren know nuclear and coal plants have to be deiced too to work in winter?
I see the answer, run hot water lines up the shaft and through the blades. All they need is a coal fired boiler at the bottom to heat the water.
Coat the blade surfaces with Teflon. The ice will not stick. Or add a 'shaker' phase to the rotation on spin-up. Shake each blade as it approaches BDC, kinda like a "bump", and the ice will fall off, straight down. Even a 'noise cannon' could dislodge ice if designed to the proper frequency to get the blades to flex appropriately.
Then again, I don't have the BSME that could have been applied at construction instead of after the face. What do they do in Denmark and Germany, both being subject to similar weather?
Hey, xtmar, I've been banned from The Atlantic Discussions. Enjoyed engaging with you.
It's always a pleasure! Do let me know where you end up, or else shoot me an email.
Yeah, I'll need to find some place to write, since it is one of my favorite hobbies. If I was less of of a egotist in need of readers, I suppose I could just write a journal to myself. Hmmmmm........
Hey, xtmar, lost your email address. Wanted to pass this along.....
......as an interesting contrast, with how somebody will be dealt with if they were to
, oh, I dunno, work for the CIA, and illegally access databases belonging to the Senate Intelligence Committee.
People who have the poor judgement to not be connected need to be shown the error of their ways!