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Your plane would have to go very fast to keep up with the sun... and would take a lot of energy.
As far as solar concentrators and trackers. There are a number of different designs that are effective. Some solar cells such as the Boeing/Emcore triple junction cells work best with concentrated sunlight.However, for ordinary solar panels, excess heat is a problem.
As far as your flower shape, you can also make a parabolic solar panel, somewhat like a large satellite dish. It will give you very concentrated heat in the middle, or at the focal point you choose.I have a set of parabolic solar hot water panels (yet to install), but using a similar idea.
Quote from: CliffordK on 31/03/2011 19:47:08Your plane would have to go very fast to keep up with the sun... and would take a lot of energy.It would have to keep up with the turning of the earth.If it takes off mid morning and get back mid evening the next day took off at 10am got back the next day at 5pm that would be 31 hours. It could just fly arround the pole ofcourse.
Quote from: Wiybit on 31/03/2011 20:55:51Quote from: CliffordK on 31/03/2011 19:47:08Your plane would have to go very fast to keep up with the sun... and would take a lot of energy.It would have to keep up with the turning of the earth.If it takes off mid morning and get back mid evening the next day took off at 10am got back the next day at 5pm that would be 31 hours. It could just fly arround the pole ofcourse.I looked at travel times... London to JFK is about 8 hrs air-time, and 3 hrs "clock time". 11.5 hrs from London to LAX. Hmmm, only about 3.5 hrs "clock time".Conventional planes are still energy inefficient.Perhaps solar Zeppelins.Hydrogen or Helium?
But you would likely be heavily dependent on Jetstreams which travel from West to East... But, then you would have a shortened day rather than a lengthened day.I still think your benefits of such a program would be minimal unless your primary reason for the flights was transportation. For example, you might try a West to East around the world Zeppelin Mail Service.
Your benefits of high altitude solar panels would likely be restricted to getting above the cloud and smog levels. Otherwise it would be much better just to use terrestrial collectors.You might be able to effectively use a tethered balloon. Or... you could likely be able to make a large solar kite. However, with that in mind, the question would be whether it is better to collect solar energy, or wind energy (or both) from your kite platform. ----There was a topic earlier about beaming power down from satellites which was effectively building a solar concentrator in space, and targeting it on a small area on the surface (perhaps also changing the spectrum).
----Perhaps the next "oil boom" in the Sahara will not be oil, but rather sunlight.I could certainly envision large solar arrays to collect power for all the northern African cities, and perhaps even southern Spain.
I think you'd be better off with power lines than batteries.Although, I could imagine converting a super-tanker to a giant battery. Push off from North Africa. Head across the sea to Southern France and plug it in. Your conversion efficiency would likely be less than 50%.
So, the question would be whether it would be more or less efficient than using direct transmission lines.Again, I think you'd be better off with your Zeppelin mail than batteries.
For one thing, batteries are relatively heavy. Your net energy gains would be in displacing other transportation methods.
Hydrogen is about half the density if Helium, so it would have obvious benefits for creating lift, but obviously there are problems with flammability.the LEL for H2 gas is about 4%. So, one should be pretty safe with using a 4% H2, 96% He mix. It wouldn't make a big difference, but it might have benefits. Perhaps one could even test higher percentages of H2.
Umm beaming electricity seems a bit dodgy.
Batteries are woefully heavy and inefficient, why on earth would you try to charge them not on earth?
Quote from: Wiybit on 02/04/2011 20:47:38Umm beaming electricity seems a bit dodgy.He said power not electricity.
Electricity is the movement of electrons, solar satellites would not beam electricty but microwaves.
Quote from: Madidus_Scientia on 03/04/2011 15:22:24Electricity is the movement of electrons, solar satellites would not beam electricty but microwaves.sorry I think electricity would be safer, whole microwaves?
Quote from: Wiybit on 03/04/2011 15:36:24Quote from: Madidus_Scientia on 03/04/2011 15:22:24Electricity is the movement of electrons, solar satellites would not beam electricty but microwaves.sorry I think electricity would be safer, whole microwaves?I don't think I specified the wavelength.
Electricity is the movement of electrons.Microwaves, X-Rays, UV, IR, and Visible light are all the movements of photons.The only way to beam electricity is to create an artificial lightening bolt which would be extremely dangerous. And, it would be difficult to keep it going where one wanted it to go. Air resistance is also high, and there would be significant energy loss from the beam.A laser (of your favorite spectrum) would have much less jumping and diffusion.For space based solar collectors, one could either concentrate sunlight and beam the concentrated sunlight to earth (which would still be subject to cloud cover and other issues)
, or one could generate electricity, and then convert the electricity to microwaves, or something similar, and beam down the microwaves, and convert them back to electricity. The proposed energy levels are low enough that you could safely fly an airplane through the beam an not harm the passengers.
The implementation of such a system, however, would be extremely expensive.If we are ever capable of building a carbon nanotube based space elevator. Graphite, Carbon Fiber, and Carbon Nanotubes are all excellent conductors. But, such a system is probably at least a century in the future, and to be effective for direct electricity conduction, one would have to design a + & - electrical pathway which might double the required effort to build it. Even so, a 36,000 km "wire" from a geosynchronous orbit would have significant resistance loss, and might be less efficient than the microwave energy conversion and transfer method.
I think that brings us back to the only practical place to implement solar panels for generating electricity to be used on earth is right here on earth.
Solar concentrators are only used because mirrors and lenses may be cheaper to make than the individual solar cells. And, as mentioned, some solar cells such as the Boeing/Emcore triple junction cells have increased efficiency with concentrated light. But... in general, a 1 m2 concentrator would not generate any more power than a 1 m2 solar panel.The conversion efficiency of your typical silicone based solar cell is about 10-20%.The conversion efficiency of the triple junction cells with concentrated light is as high as 41%.Most solar panels are sold with a watt rating. Large panels are often in the 100W to 200W range.My earlier experiments indicated that that was a little high of a rating, but I had old panels set at a fixed angle. I was also getting about 10% or less of the normal power on cloudy days. I have some better tests planned, but not implemented yet.
Anyway, with a little luck, with a 200W solar panel, you might get 200 Watt-hrs on a sunny day, and 20 Watt-hrs on a cloudy day.This website has some good forums for alternative energy:...sorry, you cannot view external links. To see them, please
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They will chew you up if you don't formulate your question well. They may have some links to resources to find the average daily solar energy at different latitudes, from which you should be able to calculate the daily power generated based on the conversion efficiency of your panels.
Hopefully I'll get some panels deployed again this year, and likely with a tracker.I think the tracking electronics are relatively simple. But, I have also wondered if it would be better to just program in where the sun will be. Then perhaps rotate 1 degree every 4 minutes (or so).
The power efficiency lost by not tracking the sun is much greater than merely using geometry to calculate the area exposed to the sun.A concentrated system, however, must have fairly accurate solar tracking, otherwise it is ineffective. On a cloudy day, you have two effects. Obviously you get less sunlight. But, you also get a diffuse nature of the sunlight. Generally slightly more in the direction of the sun, but overall diffuse across the sky. It is much more difficult to design a concentrator for a diffuse light source than a point-source.
I'm not sure if it is best to track the sun, or shut down the tracker on a cloudy day (unless the sun periodically pokes through the clouds). For some time now, I've been planning on doing some tests with the Sanyo Bifacial panels on cloudy days. ...sorry, you cannot view external links. To see them, please
REGISTER or LOGINMy idea is that while the gain from the back side is minimal on a sunny day, the gain is proportionally more on a cloudy day. However, the point might be that double nothing is still nothing. At this point, the Sanyo panels seem to be more expensive than other brands, and thus it might be better to just buy larger single-sided panels.