Vertical Axis Windmill Tower for densely populated areas by terrautopia

Dear Jorge,

I updated the proposal.

Please let me know if there is anything else you think I should add.

Thanks,

Emil

This proposal has some innovative design so I want to encourage the author to improve it by fixing the below flaws:

The title says "Vertical axis ..."
The Pitch says "Horizontal axis"
Inconsistent.

Value proposition says "CHEAPER"
but there are no dollar signs in this proposal.

The smaller versions of this have potential.
(for one house or for one business)
The larger ones don't because of the corruption
of large energy actors in our economy.
Large scale energy is just too inefficient economically
because of this corruption. (Nuclear power has the same
problem as do large scale wind farms, etc.) We should strive to make each building self-sufficient energy-wise and not have a grid.

Batteries that can support intermittent sources of power like wind and solar are coming so we should not discount proposals such as this one for not supplying energy storage. The author is talented enough to find a way to integrate energy storage into these structures. Perhaps a "gravity battery" is appropriate given that the structure already provides "height".

Perhaps there's surface area on these wind turbines to ALSO have solar panels to give us both wind and sun power from one structure.

Dear Judges,

We are working on calculations in relation to a traditional 2MW wind turbine - estimated between $3-4m installed.

http://www.windustry.org/how_much_do_wind_turbines_cost

Our model will have a comparable height of 300 ft, and a diameter of 30 ft. From preliminary calculations of this scale we are showing significantly greater output than traditional 2MW wind turbine.

In terms of costs the materials and construction of our model comes to about half of the equivalent horizontal axis windmill.

Budget Estimates for Vertical Windmill with Height 300ft and Diameter 30ft

concrete pole 300 ft tall -  1x1 ft ->  300 cubic feet per pole --  cost of concrete per cubic ft 4 dollars

cost of concrete per pole $1200 dollars

cost of concrete 6 poles 12000 dollars for 1800 cub feet of concrete

https://www.concretenetwork.com/concrete-prices.html  

Cost of steel per cubic foot 160 http://www.pages.drexel.edu/~jpm55/AE390/A3/materialsparams.htm  

TRIPPLE the total concrete from 1800 to 5400 cubic feet of concrete ->$36,000 concrete 

Assume 10% of concrete to be steel  - i.e. 540 cubic feet of steel 86,400 dollars

Total of $122,400   for steel and concrete structure materials

Cost of each rotating element (6ft tall)  with blades, flaps, stabilizing wheels = $2,000 dollars

Height of 300 feet fits maximum 50 rotating elements i.e. $100,000

Cost of a generator  $300,000

Cost of netting or “blinds” coverage for safety $50,000

Total cost of materials $572,400 materials and equipment   

Dividing the 300 ft tall structure into 50  units - and assuming labor costs of $20k for every 6ft including installation of rotating element  $1,000,000 labor costs

Software and hardware $200,000

$1,772,400 TOTAL

 -----------------

We will be providing detailed calculations of energy produced.

Thank you,

Emil Jacob 

Hey everyone,

I am a graduate student in Electrical Engineering at MIT who is working with Emil on this project.
I would like to add some technical information about the functionality of Emil's design.

 

Upper Limit on Energy Extraction from Air:

There is an upper bound to the amount of energy that can be extracted from the air. This is defined by Betz’s law: https://en.wikipedia.org/wiki/Betz%27s_law

Betz’s law says that for any wind flowing through an open space that no more than 59.3% of the kinetic energy of this wind can be extracted. Modern windmills fall short of this limit, often hitting 35% energy conversion efficiency.

 

Estimate for Energy Extracted By Vertical Windmill with Height 300ft and Diameter 30ft

Assuming an efficiency of 35% and that air density is comparable with air close to sea level, we calculate the following graph using the equation:

windpower = 1/2 *rho * A *V3

Where rho is the density of air in kilograms per cubic meter, A is the area that is swept by the turbine in square meters, and V is the velocity of the wind in meters per second.

It is from this graph that we can see that there is the potential to harvest up to 10 megawatts of power from wind are speeds close to 35 meters per second. Since more turbines are rated for 2-3MW, this will mean that at speeds greater than at least 14 meters per second the turbine will be working at full capacity.

 

Estimate for Energy Extracted By Vertical Windmill with Height 6ft and Diameter 1ft

Using a similar method as above we want to calculate how much power can be captured from a vertical windmill with a height of 6ft and a diameter of 1ft. From this method we find that it is possible for these structures to capture several kilowatts of power within favorable wind conditions.

Estimate for Solar Energy Captured at the Vertical Windmill with Height 300ft and Diameter 30ft

 

Conventional solar panels have an power output of 15 watts per square foot. This means that for this windmill that if solar panels are placed on the roof that they could generate 10600 watts of power.

 

Estimate for Solar Energy Captured at the Vertical Windmill with Height 6ft and Diameter 1ft

 

Using a similar calculation to above we find that a smaller windmill with a 1ft diameter will generate about 11.7 Watts.

 

Budget Estimates for Vertical Windmill with Height 300ft and Diameter 30ft

concrete pole 300 ft tall -  1x1 ft = 12000 dollars for 1800 cub feet of concrete https://www.concretenetwork.com/concrete-prices.html  

Cost of steel per cubic foot 160 http://www.pages.drexel.edu/~jpm55/AE390/A3/materialsparams.htm  

For the final design we can assume that 10% of the concrete will contain steel, this means that using the above costs per cubic foot that the cost of concrete and steel woul be 122,400 dollars

 

A 300 foot structure fits a maximum of 50 rotating elements such as blades and flaps. Assuming that in the worst case that each element costs $2000 then total cost for rotating elements is $100,000

 

A generator for a 300 foot structure will cost $300,000

 

A netting for covering the structure will cost at most $50,000

 

This means that our total cost of materials and equipment will be $572,400

 

Labor for installation is assumed to be $20k for every 6ft segment. This means that for a 300 foot structure there wil be $1 million in labor costs

 

Additional software and hardware for monitoring the system will likely cost $200,000

 

$1,772,400 TOTAL

 

New England Electrical Grid and the Duck Problem

 

The duck problem is a problem that arises whenever there is an excess of solar energy sources within an electrical grid. Since solar energy can only be generated during the day this means that in order to compensate for the lowered demand on the grid, power utilities have to shut down power stations to avoid overloading the grid. This image demonstrates the effect of the duck curve:

 

 

As more and more solar energy sources become attached to the grid, this becomes a bigger problem. It is for this reason that certain states have solar caps.

 

One benefit of the vertical axis windmill is that it can be used to offset solar energy's effect to the electrical grid. This can be done by storing wind energy throughout the day and then putting that stored energy back into the grid as the sun starts to set. In this way power plants no longer need to be shut down and turned on again, saving lots of energy and time.

 

 

An added feature that brings further advantage to this model is the ability to store and control energy output.

Cylindrical reservoir at the center in the image below is used for storing water 68 which is pushed up along the walls of the reservoir through outer enclosure 52. Underground  there is a water storage tank 71 from where water is pushed upwards along area 51 between outer part 52  and cylindrical wall 66. Propeller 74 is turned by the water pressure from inside the cylindrical wall and turning the generator 76.

Given the height of 300' and the diameter of  about 10' the force of the water pressing against the propeller 74 produces a significant amount of power. Having the water-battery has many other advantages, including the ability to control the power output into the the grid. In addition this feature is more cost efficient than battery technology. 

 

This model can be incorporated into new construction and provides valuable economies of scale. In other words when a high rise building is being built the additional cost for the concrete and steel required is lower than when the windmill is being built independently from a new building. 

   

  

 

CONCLUSION: We believe that the combination of the power storage and the design of the wind blades for maximum power capture via  horizontal and vertical dynamic flappers makes this windmill model an essential tool for providing cheap and clean energy for the future.