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Wind Turbines- rotor


gordon_dunn
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  • 2 years later...

The picture shows vapour trails behind each turbine.

Under some humidity and temperature conditions, vapour trails can be generated by relatively small pressure changes, such as occur where the moving air contacts the turbine blades.

What the vapour trails show is very little disturbance of the air behind the turbines.

If there were any significant turbulence in the lee of the turbines, they would have to be staggered to maintain the efficiency of the second and subsequent rows.

There are other good reasons for keeping clear of wind turbines.

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Not quite vapour trails PT: to be really anal what this fantastic pic shows is mixing. A vapour trail is condensation of moisture in clear air precipitated by the aerofoil induced pressure changes. This photo shows the existing cold/damp layer already creating fog at the water surface then being mixed by the turbine's wake with cooler air above. This mixing causes more condensation downwind and is effectively the opposite of radiation fog on land.

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Hi.

Dew point is the temp that water in the air becomes visible. The air temp and dew point were probably only 1degree different and the increase in air speed over the surface of the aerofoil (Bernoulli and Venturi effect) caused the temp of that air to drop to dew point. Hence the water in the air becoming visible.

The wind behind turbines is rarely turbulent in the conditions we fly in. Which is just as well because I am surrounded by both wind farms and stand alone Farmers turbines.

I am more concerned about the sola panel farms that are springing up everywhere and what a mid summer midday blast from one of them may bring.

:coptor:

Edited by Guest
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Simon can you delete tis and the next repeat. iPad finger trouble and I can't find out how to delete it. Cheers matey.

Hi.

Dew point is the temp that water in the air becomes visible. The air temp and dew point were probably only 1degree different and the increase in air speed over the surface of the aerofoil (Bernoulli and Venturi effect) caused the temp of that air to drop to dew point. Hence the water in the air becoming visible.

The wind behind turbines is rarely tut ulnar in the conditions we fly in. Which is just as well because I am surrounded by both wind farms and stand alone Farmers turbines.

I am more concerned about the sola panel farms that are springing up everywhere and what a mid summer midday blast from one of them may bring.

:coptor:

Edited by Guest
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Hi.

Dew point is the temp that water in the air becomes visible. The air temp and dew point were probably only 1degree different and the increase in air speed over the surface of the aerofoil (Bernoulli and Venturi effect) caused the temp of that air to drop to dew point. Hence the water in the air becoming visible.

The wind behind turbines is rarely tut ulnar in the conditions we fly in. Which is just as well because I am surrounded by both wind farms and stand alone Farmers turbines.

I am more concerned about the sola panel farms that are springing up everywhere and what a mid summer midday blast from one of them may bring.

:coptor:

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Solar panels extract some of the incident energy as electricity. They are not very efficient at it, so quote a bit of heat is generated within the panels.

The theoretical maximum possible efficiency of a single junction silicon cell of about 15%. This means that almost 85% of the energy is converted to heat, increasing the temperature of the cells a fair bit. Maximum incident energy on a warm summers day is something like 120 Watts per square meter, so a one square meter panel will receive approximately 120 joules a second of total insolation.

Of this, 15% (18 watts) will be converted to electricity.

So you have 102 watts of energy to dissipate. Most of this will be transferred to heat energy.

Without looking up the SHC of the materials, I can't work out the actual temperature reached, but a dark surface on a warm day will reach quite a temperature. Now imagine that reduced by 15% (ok, maybe a bit more due to air movement) and you will see that the solar panels will get pretty warm, and if there are a lot of them in a smallish area the thermals could get quite interesting.

Granted, they will not be as warm as a road or similar, though possibly warmer than a light coloured structure like concrete.

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