https://forum.awesystems.info/t/an-alternative-method-to-tap-high-altitude-winds/949/14?u=pierreb
See the “Table 5 Reference photovoltaic plant considered for hydrogen production”.
As the photovoltaic plant is onboard, some dangerous handling can be avoided.
All things considered Long permanence high altitude airships: the opportunity of hydrogen is an interesting track for all AWES.
“KIS” rather than “KISS”, politely removes the final “S” for “Stupid”. Its more professional that way.
Let those who imagine balloons to be relevant to AWE test them. Kytoons date back a century or more. KiteShip and KiteLab Portland developed several rather nice Kytoons in 2007, but they were not found worth LTA operational burdens. When I traveled West to join KiteShip, a helium regulator was in my single bag of luggage.
Windy Skies: “With electric heating you don’t need to rely on a single heat source. You can distribute the heat sources inside your balloon, and their output, and see how that effects convection. Also with the addition of baffles or the like we’ve already left the “normal balloon shape” behind.”
This approach to electric heating adds a lot of wiring mass. The solar panels would likely be rationed on one side to save mass and cost. Internal baffles need not change the external shape.
I am not recommending any fixes here, just pointing out known barriers. Internal CFD cannot give a feel for how marginal the whole architecture is, just distract.
This sort of fringe AWES concept comes down to the lack of available talent to prove how poor it is, by at least making a compelling attempt.
Passive solar is still marginal, but at least saves the cost and mass of the PV-heater cycle.
Though LTA is an interesting thought, I don’t see much practicality in it. There are a few more practical options imho:
The first two options will require all losses to be continually replenished. For a wing, the glide number (lift to drag ratio) describes the amount of losses per generated lift. High glide numbers will account for less power used during lulls. If the tether is very long and moving through the air, the drag is quite large and the power used to stay airborne during lulls will probably offset the power produced otherwise.
For electrical power transmission, the conductive tether adds substantial weight further increasing no-wind power consumption.
If you want a permanent lifter to stay at an high altitude, «dancing kites» with really high efficiency seems the only option worth pursuing to me.
If the lifter must stay airborne during the worst storms, I would argue that most huge superlightweight structures (such as LTA) are just not feasible. Unless you accept blowdown, such structures must have a certain glide number in high winds that will determine the elevation angle of the tether. The problem is reducing the drag of such structures, and once drag is minimized, how to sustain the lift that must be somewhat larger than the drag, and increasing with windspeed to the power of two.
I just dont see it happening for energy producing kites at scale.
For now at least, I am content pursuing AWE that is landed for low winds and high winds. It’s the pragmatic approach. Automatic landing and launch is an unsexy option, but compared to these other options, it is doable without inventing a new technology.
The pragmatic solution: either a simple tower or motorized drone to initiate launch, perhaps as a taxi that detached from the energy producing rig or built into the rig itself. Russian doll «Matrushka» increase in size of lifter kites may be a path to huge scale without weight and cost penalties.
Now if we still want to pursue LTA or ground based energized kites, perhaps they could be feasible at lowest possible altitude to keep the drag and weight to a minimum. For LTA gas in the form og hydrogen could be supplied through a tube and the gas could be produced at the ground. Once the wind blows, it could turn into a kite using ram-air construction and able to supply considerable utility lift.
All this being said, a simple tower/mast or a taxi drone seem the most viable options right now.
That’s an artificial and unnecessary requirement. Without that requirement current technology is already capable, even if too expensive for the application.
+1
No mention I think in this thread of airborne PV panels + hot air balloons.
If you want to make a hot air balloon that doesn’t lose so much heat, you’ll have to rely on stagnant gas. There’s different approaches you could try for that, and CFD analyses of your designs is the quickest way to weed out the non-starters, and refine your thinking. I also invoke rule #17.
WIndy Skies: “No mention I think in this thread of airborne PV panels + hot air balloons.”
“PV-heater cycle” is a definite mention-
Let Active Solar be understood as a hot air balloon heated by PV panels. CFD is not “the quickest way to weed out non-starters, and refine…thinking”. LTA/AWE heuristics have already defined this architectural space as unpromising. Let CFD naturally continue to languish as a poor predictive tool in AWES design.