Vertical Axis Wind Turbine

Wind Turbines are an effective way of harnessing energy from a natural source. Many companies are looking into 'green' energy alternatives as the price and cost to the environment of fossil fuels rise. 

We are a team of second year Product Design Engineering students from Glasgow School of Art and Glasgow University.

Our aim was to produce the most efficient wind turbine out of the time and resources we had at our disposal. We researched many different designs and developed them until we reached our final solution.

Our design is based around a purpose built wind tunnel that we used to test our concepts and final design. The dimensions given could be scaled up or down depending on the application.

The following step-by-step guide will show you how you too can produce a cost-effective wind turbine.



Materials:

medium-density fibreboard (MDF)
sheet aluminium 
extruded polystyrene foam
hardwood dowel
ball bearings
two bought-in gears
bought-in generator


Joining techniques:

panel pins
screws
PVA glue
hot glue sticks


Tools:

power drill
hand-held jigsaw
sand paper
hammer
metal file
tin snips
allen key
hot glue gun
bandsaw
sheet bender
guillotine
router
belt sander
hole punch

Step 1: Fan Base

The fan is one of the most important components in this design.

The MDF base is made of two 300mm diameter discs, with a 260mm diameter disc in between - all 18mm thick. These were roughly cut to shape using a bandsaw and then accurately sized using a belt sander. A hot glue gun and 30 x 1.6mm panel pins were used to attach the discs together.

The lower-most disc was cut to size the same way as the other discs. This disc had a 155mm outer diameter channel cut out using a router. The channel is for the ball bearings to run and its width was 6mm (chosen due to the ball bearings purchased).

Through all four discs is the hardwood dowel axle - 22mm in diameter - cut to 240mm in length using a bandsaw. A hole of the same diameter as the axle was cut through all the discs using a pillar drill. The axle was forced through and required no glue due to the accurate fit.

Comments

[Kardolf]

I would love to hear how much power this design actually produced. Did the curved tops of the fan blades have any impact on power output? My first thought was that they would not hold the air as well, and would reduce the output, but perhaps the lower mass or allowed for a higher speed, and more output?

[dimtick]

I read about a commercial version of this in which the blade unit used magnets so that it would litterally float above the base unit. the claim is that this reduced the spin friction down to next to nothing so that it would spin and be very efficient in very low wind speeds.
Another advantage that was claimed about this design is that in urban envirnments with buildings and trees that low level winds are very turbulant and constantly changing direction. traditional blade designs can't handle this low level turbilance which is why they're mounted up high on poles so they can catch clean air, but this design can be mounted at ground level with no loss of efficiency.

[JayGeeBSE]

You are severely mistaken. Windspeed rises from ground level up to say 100 - 200 feet. Any wind driven device at ground level will get greatly reduced wind speed to use. There is no substitute for getting the device as high as possible.

[dimtick]

my comment was not about wind velocity. it was about low level turbulance.
higher is better but there are lots of places where it's not possible like in urban or residential areas. vertical axis blade designs easily adapt to rapidly changing low level wind direction.
I did a quick google search for the turbine similar to this that i remembered. it appears that the company has gone under but here's the article.
http://www.greengeek.ca/magnetic-levitation-wind-turbines-now-available/

[JayGeeBSE]

What you wrote was "this design can be mounted at ground level with no loss of efficiency.". It can't.

[dimtick]

the problem here is your confusing my use of the word "efficiency" with "output". in this case efficiency refers to how the turbine performs in changing wind directions versus how it would perform at the same wind speed and the wind was coming from a constant direction and the turbine was perfectly aligned with the wind. this is not about what the output potential is of a low level turbine versus a output potential of a high pole mounted turbine. vertical axis turbines do not care from which way the wind blows so if the wind changes direction the turbine is still producing at 100% of what it can produce at that wind speed. there is no loss in efficiency. with a propeller turbine if the wind changes direction it'll only be producing at a fraction of what it could until it can orient itself. I'm sure that turbine designers have a term for this other than efficiency that would avoid this confusion but i don't know it.
does that make sense?
sorry for the confusion.

[JayGeeBSE]

A generator with rare earth magnets should be more efficient. As should a device with no brushes. Maybe a brushless motor used for model aircraft would work better - these have the magnets and no brushes, but generate 3 phase so would need diode rectifiers.

Putting a heat insulator round the generator is a bad thing - keep it as cool as you can.

[kbs2244]

I am woundering about carveing up 2 liter soda bottles for the blades?
Was that large curve at the top just for looks or was there a tech reason for it?

[hjjusa]

Could something like this be put on an electric car powering a generator which in turn recharges the batteries?

[churn]

Let's pretend we won't lose more than 50% through material, design, and conversion inefficiencies before we even get moving.

We can get an amount of power from the windmill exactly in proportion to the wind force pushing against the blades. This means, if we recovered half the power it took to drive 60mph, the windmill would be creating exactly that much wind resistance for our poor motor to push through. What we gained through the windmill would have to be spent to keep the vehicle going at 60mph.

Realistically, we would lose several times more than we gained through inefficiencies, and at best break even with an additional time and material expense.

Perpetual motion is less important than being able to strap a harness to the forces all around you all the time. Even the best designs for perpetual motion machines only redirect another force to propagate the desired force.

Men tried an idea like this in the past and called it a sailboat, but it was not very effective in a headwind.

[ironsmiter]

You could build a wind generator to mount to your electric car. yes.
You could use it to charge your batteries. yes.
would it be free energy? no. not even close.
You lose all sorts of power in friction(every rotating part), heat(again, in rotating parts, and resistance in wires and circuits), circuitry losses(charge control circuit eats SOME power to operate), and that's all without talking about conversion losses, etc.
Best you could probably do is, very inefficiently, recharge your 12 volt lead-acid "utility battery" from the wind generator while driving, reducing, or eliminating the need for an alternator.
A belt drive alternator, or (and this is probably the MOST efficient) a DC-DC converter to charge the auxiliary battery straight from the main pack.

If you wanted to use wind power to charge your motive batteries... You'd be better off building a free-standing turbine that fits in your trunk.
when you stop, and there's wind, set it up, and plug it in.

[rimar2000]

That would approach too close to perpetual motion, I think it is impoosible.

[Richie15]

Nope, not perpetual motion as the energy's being transferred from the wind to the car, then to the ground (oversimplified, I know - I'm no physicist).

It's no different to a solar-powered car (which I know works on a small scale, at least) and I can see no reason it wouldn't work.

I do understand why it looks like perpetuity - the car's forward motion would effectively create a wind over the blades, which may cause them to spin. But it's mainly the real wind rather than the relative wind which is driving the fan.

[tcarney57]

Solar power captures energy so completely out of the car-turbine system that it's literally extraterrestrial! Almost all the energy to turn the turbine at road speeds would come from the car itself--from gasoline/petrol or diesel fuel. There might be random (spelled in all caps!) input from absolute wide sources, but wouldn't it be just as likely that whatever net energy gain to come at one moment (and direction) be canceled the next moment by drag?

Somehow collecting and using the huge amount of energy wasted by internal combustion would be pretty cool, though. Years ago I gave a lot of thought about ways to collect and store some of the engine's lost heat radiated and blown away---no doubt a big chunk of the total energy released from the system.

I thought a lot about using tanks of phase-change material (Glauber's salt) to store heat that could then be released by exchangers into a domestic hot-water system--essential using it to preheat the cold-water side of the water heater. I got far enough to discover a few chemo-mechanical issues--some means of stirring and reconstituting the material would be needed to maintain its energy capacity. Also, losses from the additional vehicle weight would cancel out at least some of the salvaged energy. Oh, and who wants torpedo-like tubes of "heat batteries" strapped to the top of his car?

Alas, that was many years ago and I've given no more than a passing thought to the idea.

Todd

[rimar2000]

There are many ways to recover some of the energy wasted by moving vehicles, but all without exception have technical difficulties hard to overcome.

A typical case is for example to add a heavy wheel to absorb kinetic energy during braking, for release it later in the form of thrust when needed. Can you imagine how they would benefit cyclists with such a device? It would certainly be less accidents, because when you drive bicycle you try to avoid brake, in order to not having to make the effort to regain the lost speed. Conceptually the device is very simple and easy, but when it comes to implementing the idea, the sequence of problems is so great that it explains why no one uses it.

[tcarney57]

It would be interesting to see if electric bikes could use regenerative braking the way diesel-electric locomotives do. All but completely-electric locomotives just dissipate the energy from braking in massive fan-cooled resistor grids. I wonder if a generator could be fitted to a regular bicycle that engaged only on braking, storing the energy for at least its lights.

[rimar2000]

If you manage to design such a device, solving implementation problems in a satisfactory manner, you have "taken the upper hand" (spanish "llevar el gato al agua", (to carry the cat to the water))

[ironsmiter]

"But it's mainly the real wind rather than the relative wind which is driving the fan."
The problem with that statement is...it's just not true.


AT BEST, you'll THEORETICALLY be able to extract wind energy equal to wind speed.

60 MPH head wind plus 40MPH speed limit on your road = 60 mph energy available to your turbine.
Same 60MPH wind, and 65MPH speed limit = STILL 65MPH wind available, but now most of the observed wind energy at the blades comes first from the energy first delivered OUT by the batteries through the drive train.

To get a better idea of how LARGE a set of blades you'd need to BEGIN to notice the benefit... Goto the recent instructable http://www.instructables.com/id/Downwind-Faster-Than-The-Wind-Cart/

Notice how MASSIVE the blades are in proportion to the vehicle?
Also, note the extreme aerodynamics?
Same applies to the Solar Cars.
MASSIVE solar panels, and pre-charged batteries, with extreme aerodynamics.
That is because, to extract USEFUL levels of power from these methods, you have to redefine "useful".
Many of those vehicles would sprint along like lightning, using a tiny 5HP gas motor.

Probably the BIGGEST reason not to use a turbine to recharge your batteries, while driving is... you have to get that wind TO the turbine.
You'd be much better off spending your time and energy making your vehicle present a smaller aero profile to reduce coefficient of drag, instead of INCREASING your CD, and attempting to convert some of that into usable power through use of a turbine.

[rimar2000]

If you recharge the batteries with the wind flow produced by the movement of the car, you are "eating your tail". I have seen some devices using that configuration, they apparently work well, but it is only due to the available energy is greater than the lose.

[churn]

Let's pretend we won't lose more than 50% through material, design, and conversion inefficiencies before we even get moving.

We can get an amount of power from the windmill exactly in proportion to the wind force pushing against the blades. This means, if we recovered half the power it took to drive 60mph, the windmill would be creating exactly that much wind resistance for our poor motor to push through. What we gained through the windmill would have to be spent to keep the vehicle going at 60mph.

Realistically, we would lose several times more than we gained through inefficiencies, and at best break even with an additional time and material expense.

Perpetual motion is less important than being able to strap a harness to the forces all around you all the time. Even the best designs for perpetual motion machines only redirect another force to propagate the desired force.

[dsandds2003]

This is a great idea. I was wondering if you have a pattern for the blade or how did you determin what kind of pitch to use?
Also maybe some kind of tail on the part that catches the wind so it could turn into the wind.
This is a really neat idea!!
Also if you didn't want to use a motor you might get better results using thread bobbins with copper wire around and counter sunk into the wood base and neodine recycled from old hard drives to generate the electricity.
So many ideas....soooooo cool

[patron_zero]

Pardon what could be considered a 'noob' question but could one 'stack' the blades assemblies to create a 'pole' or pylon configuration and would such work and better than say a vertical collector with a 'single' vane design ?

Thanks for sharing !

[PDEwasps]

cool design guyzzzz

[Kiteman]

It's very cool that you're all using Instructables to document your projects.

Since there seem to be quite a few of you, it would be good if somebody (your lecturer or tutor?) created a Group, you all joined the group and added your projects to it.  You could all then all include a link to the group in your instructables, so that members could find them all together.

(Click here to create a group)

[The Owls]

I have created a group and have told the other teams about it. Hopefully everyone will post their instructables to the group for everyone's viewing.

[Kiteman]

Excellent.

[lemonie]

You state "Our aim was to produce the most efficient wind turbine" - how did you arrive at this design with regard to efficiency, and was efficiency ever measured?

L

[The Owls]

The design was chosen based on a number of factors: 1) maximum power output 2) design for a commercial environment - not look out of place on a building or house 3) maximum speed of prototypes of different designs that we tested.
Once we made the full turbine to this design we then tweaked different aspects to try and maximise efficiency.

Efficiency can be calculated based on diameter of the blades and the voltage and power output.

[lemonie]

Was efficiency ever measured, and do you have some data?

L

[magelord]

Great build and great documenting.

Suggestion: I know resistivity increases with temperature. Depending on the temperature levels experienced by your motor at full wind load, it might make a difference to loose the insulator around your motor, and allow the wind to cool it.

Or at the power levels you are dealing with the resistance of the motor windings is insignificantly increased.

Hope you get an A.

[The Owls]

The foam used is a good insulator. We did not try allowing the wind to cool the generator during use, but this may well have been something worth testing. Thank you.

[frank26080115]

How many watts can you get from this?

[The Owls]

In the wind tunnel we used (which when tested the wind speed was averaging 19mph) we managed to produce 2.5 watts consistently.
This value is heavily dependant on the gearing ratio; therefore a larger gear on the fan would increase the generator axle rpm which in turn would increase the output power.

[drewgrey]

This looks like such an easy design to produce compared to long blade models. I wonder how they would respond to be mounted in gangs. Would a proper spacing of the units increase their efficiency. Perhaps even using left and right spinning together so that one unit can act as a shield for the unit behind it?

[The Owls]

The air flow through the turbine could easily be tested by using smoke and a wind tunnel. This would show where to place more units to optimise efficiency.

[rimar2000]

Good project!

What if you add a long tail with a windscreen at the front, to avoid or deflect the negative action of the wind on the right side of the turbine? I think that that would improve it.