Storing the wind

[pntrend]

What are the holes for along the side of the tube?

[mikerjuk]

Typically the lower the number of moving parts the more reliable a mechanism becomes. Here we have three main parts, two pistons and the turbine blade itself.

[rpdigital17]

Isn't it better concept to use electrolysis to generate hydrogen, and store and use hydrogen as the universal fuel for cars and home heating etc. How will you convert compressed air back to energy that is needed? It has been proved, that cars using electric engines and batteries run longer distance than cars using compressed air and when the pressure is on the lower side, then you don't reach the speed needed to follow normal traffic.

[soberek]

OK, but the video lacks explanation for the most important question? What are the principle advantages of this design over a large turbine powering a standard piston or axial compressor? In my view It definitely isn't cheaper to build, with all that tubes and pistons hundreds of feet long working well when the thing flexes and stresses under the force of the wind? Is it that much more efficient? Or is it something else? Please give us some explanation.

[mikerjuk]

@soberek He did explain this, the case against driving a conventional compressor is the same as a generator. A very large wind turbine produces a massive amount of torque at low RPM. To drive a standard piston compressor you'd have to gear this up using a huge expensive gearbox, and you then have a short stroke compressor running at high speed which is less efficient and will wear quickly. The issue I wonder about is dynamic balance with heavy pistons at opposite ends of the blades.

[soberek]

@mikerjuk U still don't get it. I'm asking, just how technology with these enormous, hundreds of feet long piston tubes is supposed to be better from the economical point of view? I'll bet a million that a few cogs for a gearbox will be way cheaper and simpler to maintain than these humongous cylinders in the rotor. And speaking of wear, what about axial (turbine) or rotary screw (like a supercharger)? Are they also worse? Remember, we are talking about cost here, how many watts per dollar.

[oasiac]

whats the difference between this and a normal wind turbine with a crankshaft on its axle powering a piston.

[AngelLestat2]

Thanks for the explanation Seamus, i am agree with all your concepts and why they have to be like that.

One question: If this turbine is soo big and it has 8 blades, four big and four smalls. What is its wind velosity estimated ranges?

The small blades it does not have piston inside dont you?

I guess that one concern with this wind turbine its their location, it has to be in low deep water for its fundation and close to very deep waters for the energy bags

Sorry my english..

[rocketplumber]

It won't scale up. At useful rotor revolution rates, the centrifugal force is far far greater than one gee, and Garvey's weights will simply rest at the outer ends of the tracks. It simply will, not. work.

[mikerjuk]

@rocketplumber Rotor speeds high enough to do this wouldn't be "useful".

[tommatdan]

there would be a far more even supply of compressed air if there where three blades

[Tonjevic]

Is it just me, or does Seamus Garvey look a bit like Terry Gilliam?

[Baronvonbadguy3]

I like this guy, he really held my attention.

[trader0108]

A google search of "elevator return energy", found that modern elevator systems in tall buildings do have special drive mechanisms that generates return energy when the elevator is going down. Thus, the complete needed technology for storing residential solar energy in a special heavy-concrete-weighted solar energy storage elevator is already available. The "overall energy" use for tall building elevators is very small ( just the cost of resistance and inefficiency ). No explosive hydrogen.

[twotexastravelers]

Your ideas to store the energy is great, and they solve one of the problem of energy storage. You can trickle the water back down through a turbine, or use the total weight of the volume of water to push hydraulics or or air. A third solution (other than pumping water or compressing air) is to use a low gear to raise a very heavy solid weight - a very old solution used in England to harness tides and power pumps in a system of canal locks.

[alastair78]

A couple of questions. I noticed your plastic tube has holes to release the air faster, wouldnt the piston take longer to compress the air without these holes thus getting only 1/2 a stroke or less in before the piston falls outwards again? It seems to compress at a higher PSI, the piston will need to weigh more slowing the blades. Also it wont work if the blades spin too fast because centrifugal force will throw the pistons towards the ends of the blade.? No?

[nottinghamscience]

Posting a (lengthy) reply on Seamus's behalf...

Part 1

Relating to holes in the plastic tube and centrifugal force, there are some inter-linked design decisions. To understand the linkage, you first start with what you cannot change. The optimal rotational speed of the turbine and the total power that is extracted from the wind are the "unchangeables". These have to do with fundamental aerodynamic issues that are the same no matter how you convert that power into a transportable form. (cont)

[nottinghamscience]

Part 2

The rotational speed tells you how many times per minute each blade will pass through a full cycle and the power then tells you how much mass there must be falling within each blade. You can choose how far the mass can fall. Obviously, the piston will not be able to reach all the way to the blade tips but we probably want it to reach more than 70% of the way. (cont)

[nottinghamscience]

Part 3

The product (2Mgh N (W/60)) is the total power that you can convert where M is the mass of the piston in one blade, N is the number of blades, h is the stroke achievable within one blade, g is the acceleration due to gravity and W is the rotational speed in revolutions per minute.

Now, you are right that the rotational speed does produce centrifugal force (CF) concerns. (cont)

[nottinghamscience]

Part 4

For small turbines, CF is many times greater than g at the blade tips and any free-running mass near to the tips will not naturally fall. As turbines become larger, the CF at the blade tips falls in proportion to the diameter, D, - basically because CF is proportional to W squared and W is inversely proportional to D. So, in very large turbines, (order of 200m diameter and above), masses will start to fall naturally when blade reaches "top dead centre". (cont)

[nottinghamscience]

Part 5

However, even at 200m the mass does not fall fast enough. Remember that as diameter increases, the mass has further and further to travel in one stroke!

So you have to do one or both of these things: (a) allow a small amount of compressed-air back into the blade to help to "kick the piston off" on its downward journey from a blade tip near to top dead centre, (b) use a direct mechanical tie between the mass in two diametrically-opposite blades. (cont)

[nottinghamscience]

Part 6

The combination of these two makes the whole thing absolutely practicable. In the case of (a), you might think that you are sacrificing some compressed-air energy but this is not so. You get the energy back at the end of stroke (less some small losses). Now about those holes. The energy-per-blade-per-stroke isn't something over which you can exert much influence (if turbine diameter has been decided). However, the pressure of air that you get out is absolutely within your control. (cont)

[nottinghamscience]

Part 7

You can either have a large amount of low-pressure air or a small amount of high pressure air. There are trade-offs both ways. High pressure causes high thermal losses. Low pressure makes it very difficult to store energy economically if you want to store it and makes the expander machinery more expensive. The holes in the tube were to allow the pistons in the demonstrator to compress only towards the end of stroke so that we could produce a small amount of high-pressure air. (cont)

[nottinghamscience]

Part 8

In a full-scale implementation, we do not use holes. Controlled valves at the blade ends allow air to leak out freely until just the right amount of air is left for the piston to be able to bring up to the reservoir pressure.

SDG

(end)

[joeyboudreau]

I like this idea.....hmmm ...will this "storing of wind" for energy overcome the fact that you are constantly changing the centre of gravity of the blades?...the center of gravity becomes lower than the center of rotation, this of course makes continuous rotation more difficult to achieve,demanding higher wind velocities....hmm. I really like this idea...like you say calculations and further experimentation will tell the tale....very nice conception and Good luck!

[dcsproject5]

Very clever idea, well explained for the slower among us (me hehe). Good work professor, this could be an excellent prospect for the environment.

[CaptAhab1]

fgbj

[Sepero1]

Thanks for posting. Nice vid.