Airborne solar wind energy systems (ASWES)

I think it could be possible except I believe (not at all an expert) each panel runs best at its own voltage/current. So if they differ even slightly in current and they are connected in series, one of them would get a higher voltage. But maybe something that could be fixed either in the panels themselves or some added electronics.

Oh at last, I feel I can add one more layer of complexity
we need to launch it from the sea to not tear it while the material is spread out

How could they have different currents if the same current is flowing through them all in series? Isn’t that like saying a single water pipe could have a different amount of water going in at one end than is coming out at the other end? Maybe I’m missing something - current leakage? What I’m thinking is the total current would be the same amount of amps for the whole string as for any one panel. It’s just the total voltage that would climb. But the voltage difference for any one panel would be the same as for a single panel. One problem I would be looking for is how many “panels” you could run in series before the total amount of voltage is too much to handle in some way.
I’m not well-versed in solar, which keeps changing, as to how much voltage you can safely “series” up to. Especially when we’re talking about thin film (new) here. I know 300-400 Volts is not a problem, I think up to 600 Volts is OK, but not so sure beyond that, although I would guess a few thousand Volts would be workable.

As I said I dont know enough about this, but let me at least make my statements clearer:

As each panel will have their own optimal current/voltage setting, it may not be easy to connect them in series, because that optimum current will not match the common current, and also the voltage leading from having a common current may damage the panels.

As far as I can tell panels are connected in parallel. Anyways I am not bothered to investigate this as its not too important at this stage. My points still hold some truth though, that the weight of electronics, stiffness of the wing, weight of cabling and the topology of cabling and voltage together are important considerations.

From the illustration of CNRS and JFG’s solar balloon project I sketched (see below) a wind energy system (WES) part, including isotropic kites (to face any wind changes) and an airborne wind turbine.

As the initial balloon seems to be able to orient everywhere to face sun due to its apparent or supposed two axes of orientation, adding wind energy seems possible and would provide some additional and significant electricity production, as well as stabilization of the set in spite of strong winds.

I think adding the WES below the balloon looks to be easier, but above could perhaps be studied, by using the two horizontal axes on either side of the balloon.

That said such an installation raises challenges at the limit of what is possible. It is the reason why I suggested untethered solar thermic and photovoltaic systems (U-SES), for uses that are certainly more limited, although they can become more important, but whose implementation seems much easier and simpler.

Suddenly I’m reminded of the perennial announcements of resurrecting the airship and blimp industry, by showing a rendering of some very large airship pr airship/blimp, filled with details of how fast it will go, how much cargo it will handle, how wonderful it will be, then it never happens. :slight_smile:

Zéphyr©, photovoltaic balloon

Multidisciplinary team project : two Product Designers, Cédric Tomissi and Julie Dautel, and one Ingeneer, Karen Assaraf.

Some modifications for an AWE use: this balloon could be a kytoon although the kite part could make shadow on the photovoltaic balloon, or a Sharp rotor, both aerostats supplying aerodynamic lift from the kite part.

Then a classic wind turbine aloft would add additional power.

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Manufacturing of ASWES is favored by the progresses in photovoltaic film encapsulated in fabric supports, that are used for wings, sails, airships. Now large areas are suitable.

Although I mentioned balloons or airships, flexible kites are also quite adapted, and if flexible ASWES are also of type fly-gen, the electrified tether is already there, as for FlygenKite.

Some features are explained on https://heole.fr/en/opv/ :

Organic photovoltaic cell technology (OPV for Organic PhotoVoltaic) is the eco-responsible transformation of light energy into directly usable electricity. It is based on polymers from organic chemistry: semiconductor polymers sensitive to light.

Advantages

  • Flexible, fine and light:
    30 times lighter than a conventional solar panel, it fits on curved surfaces and can be rolled up: it can fit on previously unused supports
  • Semi-Transparent:
    it is made up of ultra-thin layers whose unit of measurement is the nanometer, which makes it possible to capture light energy on both sides
  • Efficient even in low light:
    It produces energy even on a cloudy day, from early morning to late at night!
  • Environmentally friendly:
    Low in energy to manufacture, it does not use rare materials and is easy to recycle
  • Low-carbon process:
    they are to date the only carbon-free photovoltaic solution

It is the dream technology to design the solar sail!

Perspectives

The energy conversion efficiencies of these organic semiconductor devices are in constant progress. The energy efficiency of OPVs has jumped from year to year.

This may become a turning point for the evolution of AWES into ASWES, when the efficiency, lightness and robustness of these complex films have progressed sufficiently.

This seems at least to have some value catering to the traditional sailboat market

As for all that contains large flexible surfaces, freeing up space on the ground for photovoltaic panels, in addition to the specific use (to supply the boat with electricity on board) of pleasure or regatta sails.

As this technology is quickly progressing, perhaps some light and efficient products will be available by soon.

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Something that might interest you and many on Awes

Apparently the uk government wishes to ban solar farms on farm land as it take up too much arable land. ASWES could fill the niche? Just thought I link in the vid with a barrister talking about it.

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An alternative and simpler configuration of Airborne Solar Wind Energy Systems (ASWES) would be using mainly high altitude wind energy as any static (or crosswind) AWES operating in yo-yo mode, with solar energy used only to heat the air in a suitable kite so that the kite can remain in the air most of the time, even without wind, including night. So there would be no need for a challenging electric tether, expensive photovoltaic film, or absolute constraint on altitude.

A sketch below about two sorts of solar kites:

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A solar assisted Kitewinder system would be preferable. In the yo-yo system, retracting the LTA balloon kite may be problematic. The LTA force is vertical, so the solar assisted Kitewinder kite can provide more lifting force at higher tether angles.
A general advantage of airborne solar is the ability to supply warning lights on the device to comply with regulations.

I already tested the turning of a solar balloon by a central rope: deflation was very fast, even with large volumes. So the reel-in phase would be facilitated. And a solar balloon heats up quickly, quickly reaching its limit, adding a bit of force during power reel-out phase.

The parachute on my sketch above is a little like the balloon I tested, comprising a large opening.

Here solar energy (by day) or infrared (by night) would allow the kite to stay in the air (avoiding some takeoff and landing operations), even when there is no wind. But the power / mass ratio has to be high: it is the reason why I thought about a yo-yo system with a flexible kite. Such a use would not be possible with a turbine (Kiwee or another) aloft adding weight, above all when scaling. Indeed heat generated by infrared is not high, but can be sufficient for a kite-balloon.

When there is sunshine. But when there is no sun or by night, the lifting force and the tether angle would be lesser, and perhaps the whole system would be too heavy to stay in the air. For a stationary device, too significant changes of tether angles may also result in the loss of the advantage of being stationary.

To supply warning lights is an obvious application. There are many possible applications for ASWES that I have initiated in this topic. I described some configurations with photovoltaic films for electricity generation, and just before some methods for thermal solar energy.

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Except warning lights mostly work at night, whereas solar works in daylight.

Small batteries should not weigh too much

After some preliminary rough calculations, I must admit that a ram kite would not be voluminous enough to fly by aerostatic lift with infrared (by night), or even thermal solar energy (by day). Perhaps a suitable parachute kite could do it, working a little like an open balloon. This would be a way to stay in the air even without wind.

Another option from the modified drawing: the photovoltaic balloon becomes a kytoon in order to benefit from high winds, and above all solar energy is used only to produce hydrogen to inflate said kytoon, not to convey electricity through an electric cable.

On the one hand, it takes a lot of energy to produce hydrogen, and solar energy just allows provide it, on the other hand, it is necessary to isolate the kytoon as much as possible in the top of the installation, in order to avoid the propagation of a possible fire through the cable.

Other lifting kites and wind turbines are installed below as shown on the modified drawing. If a rope drive device like on Kiwee replaces wind turbines an electrical cable is not required. Other (crosswind or not) AWES such like fly-gen (with the requirement of the electrical cable), even perhaps some yo-yo systems (without electrical cable) could also replace wind turbines.

An example of solar panels producing hydrogen:

Examples of light flexible solar panels on sails or balloons:

Not sure how relatable this is? With something I read this morning saying an isomer can store sunlight for 18 years. @PierreB , as you have interest in the field? I wondered if you had come across this? Or even consider it applications in AWES?

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Chapter

Full-text available

Aerostat for Solar Power Generation

PDF available on https://www.researchgate.net/publication/221907407_Aerostat_for_Solar_Power_Generation

image

These two figures are extracted from the publication.

This could perhaps be an ASWES by modifying it, for example by implementing the second alternative version of the preprint (Preprint: Towards a gigantic Magnus balloon with motorized belts), sketch reproduced below:

Aerostatic lift (hydrogen or helium rather than thermal solar which is insufficient to carry the wind turbines and solar films) combined with aerodynamic lift, and perhaps more scalability with external motorized belts.