Questions tagged [wind-power]

For questions related to power (mechanical or electrical) generated from wind.

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Estimating yaw torque and power of HAWTs

I am trying to estimate the amount of torque and power required to rotate a 3 bladed Horizontal Axis Wind Turbine (HAWT) about a vertical axis("yaw" motion). I would like to estimate the ...
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3 votes
3 answers
105 views

Why not build a wind turbine like a vertical Kaplan turbine?

Vertical Kaplan turbines are often used for hydropower plants. They can have an efficiency of more than 90%. Why don't we see similar designs for wind power? I mean one could imagine to redirect wind ...
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1 vote
2 answers
206 views

Expected power increase when replacing old (>20 years) wind turbines [closed]

Plenty of onshore windfarms around the world are reaching the 20-25 year old mark and thus may be on the process of repowering. Let's say an old wind farm has 10 rotors of 0.5 MW each (total power <...
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  • 111
-1 votes
2 answers
72 views

Carbon and wind energy [closed]

I am looking for sources on the carbon intensity of wind power. Concrete doesn't directly emit CO2 but the process to make it does in fact emit it. Because concrete is made of aggregate, which ...
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2 votes
3 answers
87 views

Why wind turbine dont use high lift coefficient airfoils?

All wind turibne use low lift coefficent airfoils from 1.0 to 1.5. Why not use high CL airfoils to get maximum torque? http://airfoiltools.com/airfoil/details?airfoil=s812-nr
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2 votes
3 answers
996 views

Is the main goal for wind turbines to take maximum energy for a given diameter?

If you increase the number of blades, that will increase torque, for the same RPM you get more power,...simple logic So why only three blades, is main goal for wind turbine take maximum energy for ...
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66 views

Theoretical calculation of blade pitch angle

I would like to start by apologizing for my ignorance, I am sure I am missing something very obvious here. I am using data for the NREL 5MW reference turbine, and specifically power curve and power ...
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-1 votes
2 answers
92 views

Could the St. Louis Gateway Arch be used as a support structure for a giant vertical axis wind turbine?

I am curious to know if the St. Louis Gateway Arch would be strong enough to act as a support structure for a giant vertical axis wind turbine. I way I am envisioning this being constructed is that a ...
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2 answers
71 views

Is transmitting windmills' mechanical power to ground level that complex?

Thinking about the complications of building and maintaining turbine rooms installed at high altitudes in horizontal axis wind turbines (plus the difficulties related to it when, for example, a fire ...
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2 votes
2 answers
203 views

How do 3 blade turbines come so close to the Betz Limit?

I have seen many diagrams (see attached) that indicate that modern 3 blade turbines are nearly 50% efficient, which is about 80% of the Betz limit. Betz calculated his limit based on a theoretical ...
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3 answers
49 views

Are wind powered drones and platforms possible?

A glider is able to fly unpowered indefinitely so long as it can exploit nearby thermals and the like to stay aloft. The world record is 3,008km so perhaps there is a practical limit. I imagine this ...
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5 answers
182 views

Small water pump powered by wind turbine : what type?

I need to aerate a small pond in my garden. I would like to build an autonomous system with a small water pump. The power would come from a small vertical wind turbine I will build. Since my pond is ...
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1 vote
1 answer
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Weibull distribution Units - ENGIEQSOL

I am using Engineering Equation Solver, and it has been telling me the units of my distribution are inconsistent. According to a the book I am reading, I think it should be unitless (as it is a ...
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-1 votes
2 answers
103 views

Correct wind Weibull distribution for wind+solar system

I'm trying to forecast the peak power output for a wind + solar system. The solar output as a function of time of day and month can be forecasted easily. I also have the historical wind speed for a ...
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0 votes
0 answers
29 views

Shadow flicker validation

I am currently trying to validate a shadow flickering algorithm against some data generated by Openwind. The goal of this validation is to have a code that we know that is correct and modify it to ...
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-1 votes
1 answer
234 views

Capacity credit vs capacity factor

What is the difference between capacity factor and capacity credit? I know that capacity factor = annual generation / (installed capacity * 8760) but I don't understand how capacity credit is ...
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1 answer
43 views

Wind turbine that is efficiant from all angles [closed]

What shape propeller with a large surface are, would be best propelled from the wind from behind and from the side as well as the front while facing the sun? I am thinking a pinwheel, but maybe there ...
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1 vote
1 answer
171 views

Is a geared motor better for a DIY wind turbine?

I have decent electronic understanding, but I've not much idea about motors. I plan to make a small wind mill which should be enough to power a couple of LED lights for like an hour every day. I was ...
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-1 votes
1 answer
19 views

How can I get more power out from a windmill motor?

As far my knowledge a dynamo is a motor which provides electricity when the rotor shaft is rotated. My Question to be brief is if I connect multiple dynamos in a single shaft will I get more current? ...
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1 vote
0 answers
34 views

Can you channel more air into a nozzle by creating a vortex inside of it?

There are designs for ducting in wind turbines to channel a wider cross section of wind into the rotor area. This is unpractical for structural and economical reasons but does actually increase power ...
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1 vote
0 answers
44 views

Superimposing a Vector Field onto a Toroid in Matlab

I am a systems and control PhD student in Aerospace Engineering. Currently, I am trying to create a wind shear model of a toroidal thermal "bubble" in Matlab similar to the one in this paper (shown ...
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0 votes
2 answers
42 views

number of electric vehicles that can be charged with specific amount of energy

I used minutely sampled wind speed data for one year to calculate the yield power from specific wind turbines to be used in electric vehicles charging station. I am supposed to calculate the number ...
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-1 votes
2 answers
48 views

What is and how do you calculate the wind velocity design for wind turbines?

I am finding it difficult to get consensus on the definition of design wind speed for aeolic turbines. I thought it was the velocity that corresponds to the maximum power output, but I have already ...
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0 votes
1 answer
29 views

small gearbox for experimental wind mill

The gear box will have little torque as I am only using a 12 by 18" wing which rotates. The two shafts I am using are 1/4 ", one form the wing and the other going the to pivot for the wing to circle, ...
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1 vote
0 answers
45 views

Conceiving a wind turbine as a thermodynamic machine

Traditionally, and continuing till the present day, wind turbines are conceived/presented as power plants which harvest the (macroscopic) kinetic energy carried by an externally available airflow, ...
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1 vote
1 answer
57 views

How to estimate wind generation using power curve?

I am trying to verify windfarmer generation estimates manually. To do so I am trying to manually calculate the estimated energy production (kWh) of a wind turbine. The information I have available is ...
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2 votes
3 answers
143 views

Wind turbines with down tower power units. Why aren't they more common?

Concerning the big megawatt wind turbines, if there is such a big trouble with gearbox bearings failing much earlier than expected and costly maintanence or replacement of huge gearboxes, what is ...
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4 votes
2 answers
174 views

Do 3 blade wind turbines generate more power than a 9 blade, all else being equal?

After doing some research, I have come to the realization that 3 blade design horizontal turbines have the greatest maximum coefficient of performance. Most sources seem to agree a Cp of ~0.45 at TSR=...
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2 votes
1 answer
121 views

In horizontal axis wind turbines, why does axial component of absolute velocity stay constant (wake rotation theory)

I am having hard time understanding how does the axial component stay constant through the rotor. Every resource i look just says it is due to mass conservation but never gives the actual conservation ...
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1 vote
2 answers
81 views

Can a bridge's towers be used as wind turbines?

I come from a fairly remote island where we need a 150 min ferry ride to reach the mainland. While the island has few resources that would encourage a government to investigate the possibility of a ...
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1 vote
2 answers
195 views

Why vertical wind turbine don't be half covered

I think it would be more efficient for a vertical wind turbine to have a covered funnel about half of it Something like this figure It would protected the turbine from opposite wind and also ...
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1 vote
0 answers
31 views

Hybrid Energy Monitoring Systems

I have been doing research on renewable energy systems and I must admit that I am a newbie in this specific area. I have noticed that stand-alone systems have their own specific monitoring system ...
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2 answers
68 views

Is it possible to generate energy from indoor draft by opening windows on opposite sides of the building?

Wind flow always generates naturally when I opening windows on the opposite sides of the building. Is it possible to put turbine on the way and generate electricity from that? It could be optimising ...
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-2 votes
1 answer
35 views

How is the Ampyx Power plain generating energy? [closed]

This is what I'm talking about: Wikipedia Youtube video 1 Youtube video 2 Official site Can you please explain me on how this plane is generating energy? Reeling back the aircraft should consume the ...
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1 vote
2 answers
2k views

what is 1P frequency in rotor (wind turbine)?

In wind turbine, Is the number of revolution taken in 1s is called 1P frequency? If not, is it possible to find the 1P rpm from rpm measured for 1 hour (that is, I have 60 rpm data points from ...
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0 votes
3 answers
65 views

What determines the cost of the wind turbines?

If there is an 11kW wind turbine, and a 15kW wind turbine. Why is the 15 kw wind turbine more expensive? I know it seems like a basic question, but what exactly makes it more expensive? Is it only ...
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0 votes
3 answers
442 views

Wind measure with strain gauge

I'm trying to build my own weatherstation for my home, I want to measure temperature humidity and wind strenght and direction. For the wind I have a question. I want to measure the wind with a ball on ...
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1 vote
1 answer
63 views

Is it possible to determine tip-speed ratio from rotor geometry?

Let's say I have the geometry of the rotor: the number of blades, the airfoils that make up each blade, their position, chord length and their twist angle. Would it be possible to use this information ...
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5 votes
3 answers
911 views

Why not design a Wind Turbine like an Anemometer?

Anemometer measures wind speed. It's shaped with little cups---hollow half-spheres. That looks very logical as the cups grab the wind and the other side is rather streamligned to cut through the air ...
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1 vote
5 answers
418 views

Why isn't it possible to build a car moved by wind power?

So, first of all, I am a High School student and I wanted you to explain me something (in a more "concrete" way, if you know what I mean): I had an idea the other day to make a car with a wind turbine ...
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5 votes
2 answers
3k views

Advantages/Disadvantages of two-bladed windmill?

The vast majority of wind turbines I have ever seen feature 3 blades, as shown here: Recently while driving through western new York state, however, I passed by several turbines featuring only two ...
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0 votes
1 answer
318 views

Why did my result show "more blades on turbine = more RPM"?

I placed a normal cooling fan 45cm away from a small turbine generator. i had 3 turbines, one with 4 blades, 8 blades, and 12 blades. The one with 12 blades always rotated the fastest, even after ...
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4 votes
1 answer
404 views

Why does my model of a wind turbine show high RPM with low power output?

I am designing a wind turbine to generate 1300 W. I modeled the output voltage of an AC generator using the following specifics: Number coil turns = 300. Copper wire gauge = 1.02 mm. Knowing the ...
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11 votes
1 answer
3k views

How to calculate Power of motor when used as a generator?

How can you calculate how much power can be generated by a motor when used as a generator (like a motor used in a wind turbine)? Does the power depend on how fast the magnet is rotated? If so, is ...
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10 votes
3 answers
788 views

Why don't we just build a giant wind turbine?

The power generated by a wind turbine is given by: $$\mathrm{Power} = \frac{1}{2}C\rho AV^3$$ Where: $\rho = \text{Air density}$ $C = \text{Coefficient of performance}$ $A = \text{Frontal area}$ $V ...
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-2 votes
1 answer
123 views

What theoretical efficiencies can wind / hydro turbines achieve? [closed]

The high water has some energy E = mgh. In the basic school, we were told that hydropower plants extract the energy of "falling water". Now, that banned principle says that if your water falls upon ...
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5 votes
3 answers
4k views

Relationship between wind velocity, turbine rotor diameter, and power output

I'm trying to understand and identify the equations to use in defining the relationship between wind velocity, turbine rotor diameter, and power output for a wind turbine. To simplify my question, ...
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3 votes
1 answer
176 views

What is the power and max flow rate required to rotate a 300 W wind turbine?

I have purchased a wind turbine with a power of 300 W, the start up wind speed is 2.5 m/s, rated wind speed is 11 m/s, and the survival wind speed is 45 m/s, and what I'm going to do is to make an ...
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4 votes
2 answers
650 views

Efficient 3D mesh topology for CFD simulation of turbine blade

I´m developing a tool to generate an openFoam wind tunnel case of a wind turbine. I already have the blade geometry constructed, but I'm really new to CFD and parametric meshing. I found some ...
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8 votes
1 answer
101 views

To what degree are wind and water turbines exchangeable?

Assuming maximum efficiency is not the primary concern (but net positive efficiency is), to what extent could a wind turbine operate in water and vice versa? How do the different turbine types fare ...
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