Posted on 09/13/2007 7:19:00 AM PDT by Uncledave
What's ancient about modern windmills?
Windmills can capture only about 59% of the energy in the wind, from theoretical studies. Modern windmills approach that theoretical limit. The olde 16th century dutch windmills were much less efficient, that’s why they are so large in rotor area.
Having studied windmills years ago, trying to find better designs, I concluded that increasing the rotor diameter and thus tower height, wasn’t the way to go. Simple plastic sheeting stops the wind and thus you need to force it through a narrow throat, like that : )-( You see that effect w/the windmills in the canyon between LA and Palm Springs : a natural narrow throat.
So I experimented with a large cone w/small turbine hole, cone tip pointed upwind. I quickly learned that Karman Vortices will whip it back and forth on the vertical axis. Thus you need the cone base pointed upwind as a funnel to the small diameter turbine hole, let the Karman Vortices do their thing downwind.
With the cone tip upwind the unit automatically swings to any new azimuth vector, but KVs are at a max. Cone base pointed upwind means some mechanical system to keep it pointed that way, just the opposite of what it naturally wants to do(something like a windsock).
Bottom line : great areas covered w/cheap plastic film vs expensive rotors/high towers, for the same power output.
This idea will work much better in deep ocean currents, even with reversing currents : a hexagonal array of open cones(very shallow angles of cone)w/10% area openings between the circles. Thus marine life can pass thru those triangular holes.
Example : the DSC(Denmark Strait Cataract)between iceland and greenland is 25 amazon rivers worth of cold polar water pouring into the abyssal deep of the north atlantic. Capture 50% of that hydro-energy w/a 50 mile wide, 500’ deep open hydrodam(top at 1500’, below icebergs)and you could supply most of europe’s electrical needs with UG su-co cables to scotland.
Since the D means DENMARK, and they are into clean-green energy, the Danes would be the ones to meet this engineering challenge. Also, the DSC begins the world wide abyssal current that eventually ends up in the north pacific. By holding back some of that cold polar bottom water, the arctic stays cooler, somewhat mitigating global warming = arctic ocean melting(there is also the Davis Strait to consider).
So, if YOU are really into green-clean energy, look at the DSC and other large ocean currents like the Gulf Stream. The world could go into nuclear winter but these deep currents would take decades, even centuries to stop moving, and supplying electrical energy.
Yeah, that's where I'd set up a company to hire technology engineers. </s>
But note that the wind ISN’T reliable over very short - nor very long - periods of time. You’ve GOT to build (pay for! and staff and provide energy sources for) enough conventionalpower plants to cover the (frequent) periods when wind is too weak to generate power, and too strong (during storms and weather fronts) to safely generate power.) So that double capital - with the conventional plants not able to pay for themselves - makes it more difficult. Northeast Europe regional grids dropped several times recently when wind turbines dropped off line in large numbers during streams.
And it takes time for the efficient conventional power plants to come up: 24-30 hours for a nuclear, 12-16 hours for a coal plant. The disruption while they start is dangerous.
Wind is a part of the answer. But only a small part
Packy Kelly, who heads KPMG’s venture practice in Silicon Valley, said that the companies were judged on the basis of novelty of idea, size of market, value created for investors, potential impact on environment and communities, and media buzz.
They need to keep the “media buzz” going long enough to get a democrat budget through for the DOE to get subsidies “started”- then SELL! and get out.
So now you’re a windmill expert with a better idea? I simply can’t keep up with the changes in direction.
It’s called a shift in the azimuth vector, as the windmill swings around a vertical axis to turn face-on to the wind. The old farm windmills had a rear tail to do just that, and you locked them off by holding the tail sideways, against the rotors, so that the wind vector hits the rotor edge-on.
This is proving to be an uphill learning curve for you. Consider the rotor area and the fluid : air. To get significant power the wind speed has to get above 12-13 mph, overcoming internal bearing frictions, etc. Above that it goes up by the cube of velocity. At hurricane velocities you need to feather or lower the angle of attack of the blades, or it gets torn apart. Also, the velocity is variable = variable power output.
Power engineers do NOT appreciate this variabilty of output, a CONSTANT output is much easier to work with. Thus you need a storage mechanism(some kind of “spring”)that takes variable wind energy input in one end and constant output into the grid on the other end. This adds to the complexity and cost of the system.
Compare this with a hydroelectric dam, fluid : water(770 times as dense as air). It has a catchment area of many square miles vs just the rotor area of the windmill. Its rotor is the tiny turbine in the power house. Thus a “windmill” several square miles in area using a fluid 770 times as dense as air. AND the fluid flow via gravity is virtually 100% efficient conversion to electricity vs the max 59% efficiency of the windmill.
The PROBLEM is the limited sites hydro-dams can be built at plus the cost of the huge concrete dam. Also, long term they silt up and prevent fish migrations. And yet there is a clue here as to windmill improvements, can you see what it is?
Actually I find that you almost know something on this subject. You have quite a few errors in this paragraph like the "after that" error and the "at hurricane velocities" error. At first I thought you were so uninformed as to be talking about old style dutch windmills.
Power engineers do NOT appreciate this variabilty of output, a CONSTANT output is much easier to work with. Thus you need a storage mechanism(some kind of “spring”)that takes variable wind energy input in one end and constant output into the grid on the other end. This adds to the complexity and cost of the system.
You have two problems here too, one is that you assume there is some difference between variable power from wind farms and variable demand. The other is that you didn't factor in the reduction in the speed of the variability that comes from having lots of windfarms. This is why I referenced Denmark but you were not interested in considering their example.
You are a windmill lover to be sure, but 16th century technology is not the energy answer(s)the world is looking for, of that there is no doubt. The future will laugh at them, monuments to the limited thinking of the past.
You are certainly are out of the loop.
My loop/rotor of understanding the energy field has a much greater radius than yours.
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