06-27-2017, 11:49 AM
|
#251 (permalink)
|
Master EcoModder
Join Date: Jun 2008
Location: Earth
Posts: 5,209
Thanks: 225
Thanked 811 Times in 594 Posts
|
Quote:
Originally Posted by sendler
They are the ones doing the misleading by selling us on nameplate capacity versus cost.
|
Who exactly is "us" here? Really ignorant people?
|
|
|
Today
|
|
|
Other popular topics in this forum...
|
|
|
06-27-2017, 12:39 PM
|
#252 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,268
Thanks: 273
Thanked 3,570 Times in 2,834 Posts
|
Quote:
Originally Posted by redpoint5
Is there an advantage of mounting blades on the wind-leading side? Otherwise, I don't see why they haven't always been on the wind-trailing side. It seems the blades would automatically point into the wind when the blades are mounted downwind of the nacelle.
|
Yes.
The monopole will do something called vortex shedding.as the blades pass through this turbulent air they shutter and loose lift for a fraction of a second. This causes accelerated stress wear on the blades, blade connection plate and hub bearings.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
|
|
|
The Following 3 Users Say Thank You to oil pan 4 For This Useful Post:
|
|
06-27-2017, 01:29 PM
|
#253 (permalink)
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,908
Thanks: 3,475
Thanked 2,952 Times in 1,845 Posts
|
Quote:
Originally Posted by redpoint5
Is there an advantage of mounting blades on the wind-leading side? Otherwise, I don't see why they haven't always been on the wind-trailing side. It seems the blades would automatically point into the wind when the blades are mounted downwind of the nacelle.
|
The down wind side of the tower stresses the blades when they pass out of and then back into the wind. Remember the blades are hundreds of feet long.
|
|
|
06-27-2017, 02:42 PM
|
#254 (permalink)
|
Master EcoModder
Join Date: Aug 2012
Location: northwest of normal
Posts: 28,720
Thanks: 8,151
Thanked 8,934 Times in 7,376 Posts
|
The story was about ' Segmented Ultralight Morphing Rotors'. The segmented part is for manufacturability and deliverability. the Morphing part is that the rotor (modeled on a Palm tree trunk) absorbs the stress of the wind shadow. If the blades are upwind they have to be stiff enough to avoid a strike on the tower.
Here's another article on the segmented blade.
https://cleantechnica.com/2011/12/09...-blade-design/
They also show a turbine with a hubcap.
Ferdinand Porsche built a trailing windmill in the 1930s. I can't find a picture of it online but one appeared in a Porsche magazine called Christopher. Maybe I'll find my copy someday.
If the wind shadow is really a problem, why don't they boat tail the tower?
|
|
|
The Following User Says Thank You to freebeard For This Useful Post:
|
|
06-27-2017, 02:52 PM
|
#255 (permalink)
|
Master EcoModder
Join Date: May 2011
Location: Syracuse, NY USA
Posts: 2,935
Thanks: 326
Thanked 1,315 Times in 968 Posts
|
Quote:
Originally Posted by freebeard
If the wind shadow is really a problem, why don't they boat tail the tower?
|
The towers are fixed. But the wind shifts. Only the top nacelle with the blades pivots to face the wind. Wind turbines always have an odd nuber of blades because the wind is much stonger at the top than it is lower down near the ground. So when one blade is straight up in the best position, there are two that are not quite in the worst position to equalize the loads as much as possible to minimize rocking forces at the hub.
|
|
|
The Following 4 Users Say Thank You to sendler For This Useful Post:
|
|
06-27-2017, 03:15 PM
|
#256 (permalink)
|
Master EcoModder
Join Date: Aug 2012
Location: northwest of normal
Posts: 28,720
Thanks: 8,151
Thanked 8,934 Times in 7,376 Posts
|
The nacelle maintains the correct orientation. Instead of a full or truncated boat tail, maybe a Gurney flap on each side?
I don't really care, windmills should be indoors anyway.
|
|
|
06-27-2017, 04:24 PM
|
#257 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,268
Thanks: 273
Thanked 3,570 Times in 2,834 Posts
|
They tried it both ways, the way wind turbines are now is the best way we can currently build them.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
Last edited by oil pan 4; 01-17-2020 at 03:19 AM..
Reason: Y
|
|
|
06-29-2017, 02:46 PM
|
#258 (permalink)
|
Not Doug
Join Date: Jun 2012
Location: Show Low, AZ
Posts: 12,240
Thanks: 7,254
Thanked 2,234 Times in 1,724 Posts
|
Bizarre. I did not receive any notifications for a while and was afraid everyone stopped arguing. This is courtesy of Imgur: Converting kinetic wave power into electricity
|
|
|
06-29-2017, 02:50 PM
|
#259 (permalink)
|
Human Environmentalist
Join Date: Aug 2010
Location: Oregon
Posts: 12,819
Thanks: 4,327
Thanked 4,480 Times in 3,445 Posts
|
I've really enjoyed this thread and have learned a lot from the comments/links others have posted. While I haven't changed my main stance that there is little that can be done to curb CO2 emissions by any individual (or individual country), it has opened my eyes to the enormous challenge to replace fossil fuel power with alternatives. Perhaps a negative GDP growth rate is inevitable in the near future.
I'm all for efficiency and conservation, but without a near 100% commitment and enforcement of a well thought out plan on a global scale, CO2 output is unlikely to be reduced any significant amount. You might say my philosophy on this is more pragmatic than idealistic.
Last edited by redpoint5; 06-29-2017 at 03:18 PM..
|
|
|
06-29-2017, 09:55 PM
|
#260 (permalink)
|
Master EcoModder
Join Date: Aug 2012
Location: northwest of normal
Posts: 28,720
Thanks: 8,151
Thanked 8,934 Times in 7,376 Posts
|
Quote:
Converting kinetic wave power into electricity
|
At the end they have a statement about "If we could harness 0.1% of the world's tides, then...". Waves and tides aren't the same thing.
|
|
|
The Following User Says Thank You to freebeard For This Useful Post:
|
|
|