Ed Lenz Vertical Axis Wind Turbine: Difference between revisions
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=Kostas Latoufis Comments on Ed Lenz and Dan Connell Turbines= | =Kostas Latoufis Comments on Ed Lenz and Dan Connell Turbines= | ||
Hi Marcin, | |||
If one is going to self-build a VAWT then it should be the Ed Lenz | |||
design. It is the only one that has been around for long enough. And | |||
looking at the wind tunnel tests the efficiency seems good. | |||
Yet, wind tunnel tests can be pretty tricky and such efficiencies would | |||
be expected from a Darrieus three bladed vertical axis rotor with | |||
slender blades. I would prefer a power curve measurement which is more | |||
easy to conduct and the result can be trusted. | |||
The HAWT school of WT design has a lot to say about VAWT: | |||
www.wind-works.org/cms/index.php?id=116 | |||
> Unloaded and not set high, but survived the two worst winters in | > Unloaded and not set high, but survived the two worst winters in | ||
> Massachusetts history, apparently. | > Massachusetts history, apparently. | ||
Unloaded tests are not indicative as the torque on the shaft is almost | |||
zero so there are no stresses on the blades. The main problem with VAWT | |||
is that they have forces acting on the blades in the horizontal | |||
direction which causes fatigue and failures on the blades, but I do not | |||
have evidence for this, it is one of the disadvantages I have heard of. | |||
In addition the rotors in the links are quite small, they produce up to | |||
100W, and I wander what would happen if these were scaled up to 1kW or | |||
more. | |||
Personally, I would want a 500W to 1kW design to be installed somewhere | |||
for 2-3 years at least (preferably 5 in order to make sure all | |||
maintenance issues will have occurred), and see a measured power curve. | |||
This can be done anywhere and at a low cost. So I would encourage Dan | |||
Connells to do that. | |||
Cheers, | Cheers, | ||
Kostas | Kostas | ||
Revision as of 02:33, 9 March 2021
About
https://www.thebackshed.com/Windmill/articles/Lenz2.asp
https://www.windstuffnow.com/main/vawt.htm - 52W with 12.5mph.
Maysville MO is 17.5 average wind speed. 52*(17.5/12.5)^3 = 142W! Not bad. Supersize it with 3" shaft and we are in business. A few kw are readily available,most of the time.
Dan Connell
Kostas Latoufis Comments on Ed Lenz and Dan Connell Turbines
Hi Marcin,
If one is going to self-build a VAWT then it should be the Ed Lenz design. It is the only one that has been around for long enough. And looking at the wind tunnel tests the efficiency seems good.
Yet, wind tunnel tests can be pretty tricky and such efficiencies would be expected from a Darrieus three bladed vertical axis rotor with slender blades. I would prefer a power curve measurement which is more easy to conduct and the result can be trusted.
The HAWT school of WT design has a lot to say about VAWT: www.wind-works.org/cms/index.php?id=116
> Unloaded and not set high, but survived the two worst winters in > Massachusetts history, apparently.
Unloaded tests are not indicative as the torque on the shaft is almost zero so there are no stresses on the blades. The main problem with VAWT is that they have forces acting on the blades in the horizontal direction which causes fatigue and failures on the blades, but I do not have evidence for this, it is one of the disadvantages I have heard of.
In addition the rotors in the links are quite small, they produce up to 100W, and I wander what would happen if these were scaled up to 1kW or more.
Personally, I would want a 500W to 1kW design to be installed somewhere for 2-3 years at least (preferably 5 in order to make sure all maintenance issues will have occurred), and see a measured power curve. This can be done anywhere and at a low cost. So I would encourage Dan Connells to do that.
Cheers, Kostas