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#31
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New House Thermal
Le mercredi 28 juin 2017 14:26:00 UTC+2, a écritÂ*:
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... Energy payback means that they have generated more energy than the energy used for their production. It doesn't say anything about payback in terms of cost. Again, I'm not promoting anything. Any kind of energy has its own drawbacks, and there is no such thing as a free lunch. |
#32
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New House Thermal
Take a look at our home airfield now:
Ball Airport 145 Ball Airport Rd, Louisburg, NC 27549 36.134316, -78.281947 (Above address comes from Google Maps) Notice the tobacco fields to the east and south of the runway (North is up).. They are quite large, but soon, so I've heard, some of the tobacco will give way to solar panels. Right now, I've never found "boomers" there. I have, however, found some thermals there, and some just strong enough to keep me from falling any farther. Maybe the ponds influence that? Even when the fields are fallow, before the tobacco has been planted, nice thermals are just not normally there. When the PV panels go in, it will be interesting to know if there's a change for the better... |
#33
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New House Thermal
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#34
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New House Thermal
How much wood could a wood chuck chuck?
Good question, Mark. I often ask similar questions of people who hoot about their electric cars. On 6/27/2017 8:29 AM, wrote: Question: How much energy does it take to produce a solar array (Aluminum mining, refining, manufacture, Silicon panel manufacture, etc.)? How does it compare to the energy output of the array over its life? -- Dan, 5J |
#35
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New House Thermal
I flew a lot above big PV plants in southern France, also above the mentioned new ones on the plateau of Valensole. I didn't find more or better thermals there than elsewhere. A big factor in the development of a thermal is moisture, and there is for sure more of that in the surrounding forest than in the PV area.
I'm also not promoting PV but Bert is right about the energy payback being about 2 years. Of course that depends a lot on the region. Electric cars and gray energy is a different story... |
#37
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New House Thermal
If you want a house thermal, you want a refinery. Chicago glider club has two of them within 5 miles, and there are a lot of days in fall when cross country soaring involves a "refinery tour." Also some 7 knot thermals when nothing else is going up more than 3. Of course, if you arrive low and counting on it, you will meet the bubble theory of thermal formation first hand. It was interesting when it was shut down for a few months. You'd think sun hitting the concrete was most of it, and there was a thermal there, but the operation of the refinery made a big difference. Point your wing at the flame in the smokestack...
John Cochrane. |
#38
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New House Thermal
Adding on to Bob's thoughts, at the New Hibiscus Airpark in Vero Beach, FL, we already have three consistent thermal generators right next to the airport: a CVS distribution center just northwest, an outlet mall just east, and the Quad Lakes development just to the southwest. All are within a half mile of the pattern. Add that to the rotation of plowed fields to the west and we have a pretty nice setup here.
Adding these solar farms could significantly increase our house thermals and provide some nice, close to home, final glide thermals for those coming back from XCs. Time will tell... Paul A. |
#39
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New House Thermal
I see that some of you are physics and some know economics but no one understand thermodynamics.
All that we have is sun-radiation. A typical good day where I fly is the radiation about 500W/m^2. Some of this radiation will be reflected back to the atmosphere. This is called Albedo and is depending on the ground, in average is the albedo about 33%. The remaining energy (500 x 0,67 = 335W) will be heat into the ground and eventually thermals for us to use. If you now put a solar panel (electrical or water) into the system with and efficiency of 20%, will the ground and the air be wormer or colder? The purpose of a solar panel is to convert solar radiation to energy (electrical or heat) and transport it to another place for usage. Therefor will it be less energy left to heat up the ground/air and therefore no thermals for us to use. The only way a solar plant could be useful for us is if the albedo of the panels are so small so it compensates for the power drain it is designed to do. |
#40
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New House Thermal
On Wednesday, June 28, 2017 at 11:56:15 AM UTC-4, Dan Marotta wrote: How did the temperature of the roof surrounding the PV panels compare? -- Dan, 5J On 6/28/2017 11:36 AM, wrote: The roof is white and was about 12-15 degrees cooler than the solar panels. During my formative years in soaring, I learned (rightly or wrongly) that temperature differentials across a surface, e.g., the boundaries between forests and open spaces, dirt and rocks, etc., are good areas to look for thermals. That idea has worked for me for a long time. Maybe you'll find something there after all. Please keep us informed. -- Dan, 5J |
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