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#21
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New House Thermal
On Tuesday, June 27, 2017 at 11:50:59 AM UTC-7, Paul Agnew wrote:
Question: Does the previous question add anything to the discussion on solar farms creating thermals? There has to be a forum out there that is better suited for environmental debates. Let's focus on soaring. I routinely fly high over the Florida Power & Light solar farm near the northeast side of Lake Okeechobee. Occasionally, there are pronounced markers indicating a thermal is cooking off the panels. It's a smaller solar farm, so I'm really eager to see what the mega-solar farm does for us. Paul A. I've flown over the (boiler on a stick) solar plants near Primm, NV and haven't found they produce much lift. Haven't seen a cloud over them either. But have thermaled over the cooling tower of the Pottstown, PA nuclear power plant. First watched a dirigible fly over the towers... The deck angle went to 45 degrees up, leveled out, 45 down, leveled out. And there was a cloud. All good indicators. But these days the latter type have security people who think "shoot first, ask questions later" (there was an article about it in Soaring) so they aren't as useful for low saves as they used to be. I live and fly near many Gigawatts of PV panels. Believe one site is a good thermal source, but it wasn't bad before the plant went in. You'd think PV panels should be like an asphalt parking lot (car park), but the panels are not mounted on the ground. I know the roof of my house is cooler under the panels than the unprotected roof. Wonder if the cooler air underneath panels being brought into the thermal weakens it? Perhaps they're better lift sources in the evening? Jim |
#22
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New House Thermal
Ah, the good old days when you could legally fly over French
Nuclear power stations; now they were really good reliable thermal sources! Nowadays rumour has it that some sites have ground-to-air missiles as part of their defence; they all have exclusion zones. The reason why so little coal is burned in France is that 85+% of French power is nuclear (that's what it says on my electricity bill). The only reason that some power is solar/wind generated is that the French do not want to be seen as the most non- Green country in Europe. France has the capability to be 100% nuclear, it just doesn't want to be as not everyone is convinced that Nuclear is Green/Renewable. I will try the Vinon solar array, never noticed it to be good or reliable but that's probably just my crap thermal technique. When ETA gets going there might be a huge exclusion zone down there to spoil the fun. And here's yet another reason to be anti-nuclear power: being mostly on rivers I'd guess they are near impossible to defend against terrorists. |
#23
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New House Thermal
On Tuesday, June 27, 2017 at 7:33:56 AM UTC-4, wrote:
On 27/06/2017 19:11, Tango Whisky wrote: Le mardi 27 juin 2017 07:02:56 UTC+2, a écrit : No. Only a miniscule amount of the sunlight is turned into electricity. At this level, (electricity out / total solar energy in) the efficiency of PV panels is *buggerall*. The solar farm will probably not only not produce thermals, it will increase your energy costs. Shift to France where they have cheap nuclear AND you can go gliding in the alps! Well, physics doesn't seem to be part of your world. Today's photovoltaic solar panels run at an efficiency of about 20%. The definition of efficiency is electric power produced, divided by incident solar power. These 20% of the incident solar power are not available for heating. And if you call nuclear power "cheap", economics does seem to bother you either... As for the French Alps (where you see solar farms popping up everywhere) - that's where I fly most of the time. Physics and economics are both a good part of my world. You're just sniffy because I see it differently from you. Efficiency from solar panels is actually about 15-16% at best and when new. And of course it's hard to keep those panels facing the sun the whole 24 hours and the output is also *buggerall* in a lot of places for half the year as well. Overall? *Miniscule* is a good word. Where your physics - and economics - fall apart is when seeing in the dark and not freezing at night is factored in. Then the coal or oil fired power stations - which would be both cheap and bloody efficient during the day as well - really come into their own and make it clear that the PV panels are a just a first world sop to a warped sense of morality, defective understanding of atmospheric science and gullibility in the face of mass media hype... ...and yes, I know they're popping up all over, but lots of people being stupid doesn't lessen the degree of each one's stupidity. -- GC So does anyone else find it ironic that a pilot that flies hundreds of kg of sailplane around the sky for hundreds of km on solar power - is not a fan of solar power? Chris |
#24
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New House Thermal
On Monday, June 26, 2017 at 4:23:32 AM UTC-4, wrote:
The Treasure Coast Soaring Club will soon have a new house thermal. Florida Power And Light is in the process of building a 400 acre solar power plant within 3/4 mile from our airport. Heat from this type of farm should make for a great house thermal. Anyone out there with experience flying over solar farms? Thanks, Bob I think that this would depend on several factors specific to your location.. Two being: 1)intensity of solar radiation 2)Surface air temperature in the adjacent area. Try it and let us know. |
#25
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New House Thermal
To follow up on what Evan (T8) said: I gather the latent heat energy released via condensation in a sizable thunderstorm is similar to a small atom bomb. And that's only a side-effect of the solar input. A hydrogen bomb big enough to take billions of years to burn out gets my respect! :-)
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#26
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New House Thermal
On Tuesday, June 27, 2017 at 8:07:35 AM UTC-4, Roy B. wrote:
OK - back to the subject at hand (solar farms as thermal generators). I'm not an engineer or physicist but I suspect that part of the consideration is the mass of the structure and it's ability to hold enough heat to effectively transfer it to the air around it. So plowed fields, rock faces on mountains, and heavy metal silos do well to form thermals. But the light weight frames that hold the solar panels don't hold the heat well - and they shade the ground below them. ... Roy: "holding" the heat is not the issue. To generate a thermal it needs to pass it on to the air, not hold on to it. The sunlight coming in at 1 kilowatt per square meter offers that much enery no matter the structure. Except that some of the light is reflected rather than absorbed. Put dark solar panels (or black plastic bags) over a light-colored surface and you'll get more heat absorbed and therefore transferred to the air (minus 15% or so that gets turned into electricity in the PV panels). Put them over a surface that's already dark and there would be no effect. Also, leafy plants use some of the heat to evaporate water (drawn up by the roots), that part of the energy is "lost" to thermal generation (until condensation occurs). Remove those leafy plants and replace with solar panels (or a parking lot) and you'll avoid the evaporation and get stronger thermals. So it all "depends". |
#27
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New House Thermal
So does anyone else find it ironic that a pilot that flies hundreds of kg of sailplane around the sky for hundreds of km on solar power - is not a fan of solar power?
Chris No. Let us know when they can build solar panels in a factory powered only by solar panels. Including refining the metal bits. Same for windmills. Chasing this stuff is a net negative for energy produced and the environment(and the economy.) Is it ironic that we land in cornfields but don't like ethanol in our gas? |
#28
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New House Thermal
On Tue, 27 Jun 2017 18:01:27 -0700, greeneggsandjam wrote:
So does anyone else find it ironic that a pilot that flies hundreds of kg of sailplane around the sky for hundreds of km on solar power - is not a fan of solar power? No, not at all. All too many people have a total disconnect between the way the world is and their beliefs about how it is. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#29
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New House Thermal
Le mercredi 28 juin 2017 13:36:44 UTC+2, a écritÂ*:
No. Let us know when they can build solar panels in a factory powered only by solar panels. Including refining the metal bits. Same for windmills.. Chasing this stuff is a net negative for energy produced and the environment(and the economy.) Is it ironic that we land in cornfields but don't like ethanol in our gas? Today's solar panels have an energy payback time of less than 2 years. If you haven't noticed - the 80s and 90s are gone... Bert TW |
#30
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New House Thermal
On Wednesday, June 28, 2017 at 7:49:39 AM UTC-4, Tango Whisky wrote:
Le mercredi 28 juin 2017 13:36:44 UTC+2, a écritÂ*: No. Let us know when they can build solar panels in a factory powered only by solar panels. Including refining the metal bits. Same for windmills. Chasing this stuff is a net negative for energy produced and the environment(and the economy.) Is it ironic that we land in cornfields but don't like ethanol in our gas? Today's solar panels have an energy payback time of less than 2 years. If you haven't noticed - the 80s and 90s are gone... Bert TW Payback including gov't subsidies. The 80's and 90's are gone... |
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