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.

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...

How did the temperature of the roof surrounding the PV panels compare?

On 6/26/2017 6:43 PM, wrote:
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
lets make this somewhat simple, the temp of the solar panes on top of the hangar today was in excess of 115 degrees F. I measured the temp reading with a heat gun. The panels number about 16, and the output is a max 8kw. I don't have the output capacity of this project, but I would guess that 100 acres of solar farm could produce 20 MW therefore 400 acres would be 80MW. I would think that if those panels produced the same amount of heat as the ones on the hangar roof and heat travels up, I would assume that we would get some thermal activity from the project.

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Dan, 5J

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?

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Dan, 5J

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...

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?

On 6/26/2017 6:43 PM, wrote:
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
lets make this somewhat simple, the temp of the solar panes on top of the hangar today was in excess of 115 degrees F. I measured the temp reading with a heat gun. The panels number about 16, and the output is a max 8kw. I don't have the output capacity of this project, but I would guess that 100 acres of solar farm could produce 20 MW therefore 400 acres would be 80MW.. I would think that if those panels produced the same amount of heat as the ones on the hangar roof and heat travels up, I would assume that we would get some thermal activity from the project.

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Dan, 5J

Good question Dan. The roof is white and was about 12-15 degrees cooler than the solar panels. Also just west of the 400 acre solar project FPL is building another solar plant exactly the same size. That would be 800 total acres of panels within 2 miles of our strip. will be interesting to see what difference it makes. These farms are to be finished by September, unless a hurricane strows them all the way to Nebraska.

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.

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.

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.

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?


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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.
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Dan, 5J