Wind recording, speed and wind production?

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Christophe
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Wind recording, speed and wind production?




by Christophe » 15/11/10, 14:07

How to estimate the potential output of a future small wind turbine at home?

Let's try to think about a method with a weather station with long-term wind record and a spreadsheet, that's enough to get an idea ...

Practical example:

- I measured the wind speed between 7 / 7 / 10 and 12 / 9 / 10 usb weather station with wind recording : https://www.econologie.com/shop/station- ... p-347.html
- The mast is about 3m high on a cabanon
- Near an angle of the house (disturbance?), So it is quite unfavorable compared to a wind turbine 10m high but this is enough to give an idea.
- The recording is done every 15 minutes.

Image

Results:

I get 6460 points that give:
- Average: 2.72 km / h
- Max: 156 km / h

It's not much on average (there are a lot of points at 0) but the graphical statement indicates a wind potential which seems to me all the same more "interesting" (I limited the scale to 60 km / h for readability) ):

Image

So let's try to think of a simple method from these recordings to predict the wind generation in my case with the data of a wind turbine of this kind:

Image

a) We see quite quickly that we have to truncate everything under the 13 km / h (start of the wind turbine) and keep only the positive values ​​... which gives ... well, much more:

Image

b) To obtain the potential energy in kWh, it would now be necessary to convert these km / h into potential Watts then make an integral calculation of the curve obtained by assuming that the wind is constant over the 15 minutes.

I have never done any integration with OpenOffice so I will only look at it if there is any request from you unless someone already knows how to do it. In this case I will give him the raw data.

c) What must be remembered is that the wind potential melts ... and the interest of installing wind turbines at low speed ... but below 2m / s there is nothing or almost nothing. .What this would give from 2 m / s (7.2 km / h):

Image

It's already better ... but is it enough, in this case, to hope to amortize the investment? I doubt...

Important note: I do not know if the value recorded every 15 min is the average value on the last 15 minutes or the instantaneous value. I lean (simplicity) for instantaneous value (which would mean that in reality the potential is different: more or less important? Mmm mystery ...).

If you want, I can increase the frequency of the sampling but I can not go down under the 5 minutes which only repels the problem.

ps: subject specially made for Forhorse following: https://www.econologie.com/forums/avis-sur-e ... 10153.html
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bernardd
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by bernardd » 15/11/10, 14:24

Very interesting this station.

It seems that you can reduce to 48s between the measurements, which would be interesting at least during a test period, to check the representativeness: it is to know what is the inertia of the measuring rotor, no need to go below the delay of inertia.

For the weak wind, it is for this reason that I look for wind turbines with large number of blades, 7, 9 or 11. And that is also why I would like to have speed regulation.

And for your question on the disturbances of the house, the fir trees behind seem more disturbing, according to the prevailing winds.

Can you add on the station, or have a version, with a measure of solar luminous flux? As it can predict both the wind and solar potential.

PS: do you have the precise definitions of what is named "wind" and "gust" in the excel file? Gust seems to be the maximum during the period, but is wind then the average? The minimum would be almost as useful as the maximum :-)
Last edited by bernardd the 15 / 11 / 10, 14: 34, 1 edited once.
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by Christophe » 15/11/10, 14:32

bernardd wrote:It seems that you can decrease to 48s between measurements


Yes that is what is noted on the product sheet but I think that it concerns only the refresh on the screen and not the recording of the data.

When I configure via the soft usb it does not want to go down under the 5 minutes ...

I will re look at the record in detail because I still have a doubt ... : Idea:
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by bernardd » 15/11/10, 14:36

do you have the precise definitions of what is named "wind" and "gust" in the excel file? Gust seems to be the maximum during the period, but is wind then the average? The minimum would be almost as useful as the maximum :-)
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by Christophe » 15/11/10, 14:45

Gust is the speed of gusts. Indeed you're right, I guess it's the max recorded on the period of 15 minutes.

Which would make you think that "Wind" is the average over X minutes and not the instantaneous measurement.

There is also Windchill which is the wind chill (temperature "felt"). Besides, we can imagine a wind correction on the DJU ... It would be the best for the DPE. But hey, it is already quite difficult to understand for the general public.

I recovered the .pdf of the record, I will put it on the product sheet.

: Cheesy:

ps: taking Gust the wind potential flies but it's not very realistic ...
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by Forhorse » 15/11/10, 14:54

Very interesting.
For my part I can not afford to invest in this kind of station to do a preliminary study. I'll buy the wind turbine and I'll see the production next ...

However, since I'm going to design the load regulator myself, I'm going to try to integrate a production tracking function.

As for your installation, I would say that the location is far from optimal. We can see behind big trees that have to brake the wind almost as much as if they were in front.
And the altitude also plays a lot (I found by intervening on silos 15m high) the wind is much more powerful and more stable in height than the ground.
To make a real study of potential, it would be necessary to place the anemometer in a real situation, such as the wind turbine would be installed, otherwise it does not mean much, since almost nothing is enough to disturb the wind and therefore the "deposit"
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by Christophe » 15/11/10, 15:02

I agree with the non-optimal conditions ... which tends to reduce the measures. Especially since we are in a corner of the house, which creates a lot of disturbances ...

Nevertheless, this gives an idea of ​​what the site can produce.

Yes, the trees are a priori unfavorable but on the other hand the edge is oriented East-West and as the dominant sellers are from the West in our area, this does not reduce the potential so much ... on the contrary, we can think that it creates a "corridor" which accelerates the prevailing winds (no?) ...

It is true, after reflection, it would be interesting to make a comparative measurement to X m ... I must find a matte : Cheesy:

The link to the notice is on the product sheet: https://www.econologie.com/shop/station- ... p-347.html

ps: no candidates to help me convert curves into watts and integrate? Remundo? : Cheesy:
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by bernardd » 15/11/10, 15:19

Christophe wrote:I agree with the non-optimal conditions ... which tends to reduce the measures.


Absolutely, it's more out of curiosity. To predict a production, you will be so pessimistic.

Christophe wrote:ps: no candidates to help me convert curves into watts and integrate? Remundo? : Cheesy:


I do not know when it will be ready, but if I asked you the questions, it is that the file is already loaded :-)
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by Christophe » 15/11/10, 15:21

Uh it's not the same, I guess you mention the one zipped on the product sheet?
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by bernardd » 15/11/10, 15:40

Yes, there is another?
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