I was watching a wind turbine video on YouTube and I was thinking about why they needed to have this big cylindrical tower that’s solid and has a lot of resistance to the flow of air. The one obvious reason is so that the maintenance people can go up the stairs or lift without getting blown by the wind. But there are many tall towers that use an open structure of tubes or beams to allow the wind to pass through without exerting so much force on the tower. The old wooden windmills used to use such a structure, and the propeller turned a crankshaft that transferred an up and down motion to the ground.
I thought that there is no overriding reason why the huge, heavy generator and gears have to be up on the top of the tower. The blades’ rotation could be transferred to a reciprocating motion to actuate pistons to pump air or any fluid. The air could be sent to the ground to be stored in tanks. A fluid such as water could be pumped from a low to a high elevation. The air or fluid can then be used at any time to generate power. The air or fluid could be gathered from many turbines to power a larger, more powerful generator.
The challenges are:
1. Make the design as powerful as the wind turbines that are being built today. A megawatt or 1340 horsepower or more.
2. Make the design as simple as possible, so the cost will be less than the current wind turbines.
3. It is desirable that the design be able to store energy to be used at times of peak demand.
4. Electricity does not have to be generated at the wind turbine up on the tower.
5. The tower structure can be built to save costs.
I thought about using a chain drive from the blade shaft to the bottom shaft. That would allow the blade shaft to have a large sprocket gear and the bottom shaft to have a small, faster turning sprocket gear. But the chain drive will not allow the blade shaft to turn with the wind.
My design
I thought about the way to transfer rotational power to the bottom without regard for which direction the turbine blades were pointing. I thought a right angle gear would be able to turn a vertical shaft. But the rotational force on a single vertical shaft would instead twist the turbine blades away from the wind.
I could do what the old windmills did and put a crank on the blade shaft that would turn the shaft rotation to up and down motion. This would be transferred to another horizontal crankshaft at the bottom. The windmill’s reciprocating rod is very thin and can pull up but cannot push down – the rod would buckle. Also the rod could have stopped at the top dead center and when the wind started it up again, it would not be able to push on the bottom crank and could not start the lower shaft. So that means both blade crankshaft and bottom crankshaft need to have more than one crank. Two cranks would have the problem that the cranks could stop at top dead center and bottom dead center, and neither crank could start up the shafts.
So this means that there must be three cranks spaced at 120 degrees around the shafts. Then at least one of the cranks will be able to pull the shafts when it is not on top or bottom dead center.
But now there are three vertical connecting rods pulling, moving up and down between the top and bottom shafts. These will not allow the blade shaft to freely turn in any direction. What is needed at the blade shaft is a mechanism to allow the blade shaft to point in any direction without twisting the three connecting rods. I think that the three blade cranks should move three concentric rings up and down, and the cranks can push up on any part of the rings, allowing the cranks and shaft to rotate in any direction. Actually the single center crank would have a pair of each of the other cranks, for five total. Pairs of cranks would distribute the forces evenly around the rings. The rings would be connected to the bottom crankshaft by more than one connecting rod. It may be desirable to use more than three cranks on the bottom crankshaft in order to distribute the forces evenly around the rings.
The concentric rings pose a mechanical challenge to hold them in position while the blade shaft cranks move around them as they move up and down. Another concern I have is how much weight the mechanism will have with the blade crankshaft, rings and rods up at the top of the tower. Then there are the forces that will have to be supported by the tower as the mechanism transmits power to the bottom crankshaft.
Early on I had the idea to use the blade power to pump a fluid instead of generate electricity. The fluid idea is looking more attractive as the cranks, rings and rods mechanism gets complicated. The problem with the fluid is the coupling to the ground has to be able to turn with the blades. The large amount of power through the couplings could pose problems.