Talk:2812: Solar Panel Placement

Can someone smarter than me do the math on running power lines to a panel on the sun? How long until it would pay for itself?172.70.214.125 05:08, 8 August 2023 (UTC)

$22 million / $0.20 per kWH = 110 million kWH, divide by hours in a year and you get about 12549 kW. Google says the sun is 150 million KM away. IDK the exact details, but a calculator I found online suggests a copper cable with a cross-sectional area of 10m^2 can handle that amount of power transported 150 million KM. The density of copper's about 9 cm/g^3. 150 million km * 10 m^2 * 9 g/cm^3 = 1.35 * 10^16 kg. The cost to get one kilogram to Low-Earth Orbit according to google is >$10,000, let's just use that. Total cost to get to LEO: $1.35 * 10^20. Divide by profit per year => 6.1 trillion years. Tiln (talk) 07:10, 8 August 2023 (UTC)

"The cost to get one kilogram to Low-Earth Orbit [...], let's just use that." Ummm... It's actually easier to leave the solar system than to rendezvous with Mercury (never mind attain even closer stability to the Sun's surface).

I supose you could always go to an orbit a very long way away (near solar-escape) and add a little extra reverse delta-V to zero your orbital movement and then fall down. But you must not miss the pinprick Sun, or you're in a highly elliptic comet-like trajectory (with even higher demands needed to circularise at perihelion), so you need to be very precise about stopping and dodging through the gravity wells of any planets you plunge past. Not that not missing is going to do you much good, either.

...hmmm, hang on, maybe that's what the cables back to Earth are for. Spooled in/out just at the right rate (perhaps some bungee-chord included), it's how you stop just above the Sun's surface (at the limit of the conductive cable, then cut the retarding bungee just as you're stable enough at the bottom of the bounce!) and stay there. Ok, not a problem. It'll work after all^{[actual citation needed]} and I withdraw all my petty objections! 172.71.242.82 10:43, 8 August 2023 (UTC)

And then you'll have to deal with the end of the bungee cord retracting under it's own tension... and since it's no longer tethered to the craft it would probably whip back towards Earth. As an afterthought, have you ever been whipped by a released rubber band? Imagine that... but at a cosmic scale. I'd probably take my chances with the cables. Xkcdjerry (talk) 14:39, 8 August 2023 (UTC)

Congrats, you've just made the universe's smallest Dyson sphere component! 162.158.2.38 07:33, 8 August 2023 (UTC)

I'd just like to point out an error in Randall's math: The light incident on the panel would only be from the portion of the surface with line-of-sight to the panel. This fraction is called the "view factor", and has its own Wikipedia page, which I'm too lazy to link since I'm editing this on my phone. Carry on! 172.70.126.217 13:26, 8 August 2023 (UTC)

I thought Sun luminosity (total outgoing light, in all directions from all points of itsvsurface) divided by Sun area (total luminescing surface area) multiplied by the 1m² (the actual 'capturable' parts) normalised to the effectively-in-contact portion of the Sun exactly in the way you're defining the view factor. (You could link to View factor by just trying {{w|View factor}}, if you want, and edit it later if you're wrong.)

Further out, distance from the Sun factors in as an inverse square relationship, but it'll be negligable when you're practically at the Surface and close to the full 2pi steradian of incident light from a significantly greater area of emitting surface than the unit-area of receiving surface. Once you're at Earth-orbit distance, it's a tad below 70 nanosteradian of "panel view" and almost none of the light even from the directly facing square metre of Sun even comes close to the even smaller solid angle subtending the outwards spread of light.

Set your panel at the height of various solar-surface features, you might not intercept much of the light (hence division by Sun's area) yet what you'll capture will be significant. Probably well beyond any long-(/medium-, perhaps even short-)term survivability of a lump of plastic, silicon and metals normally stuck on a house roof. 172.70.91.161 15:36, 8 August 2023 (UTC)

I was briefly confused because HVAC usually stands for heating, ventilation, and air conditioning, but is here used to mean high-voltage alternating current. 172.69.247.50 13:31, 8 August 2023 (UTC)

I often have the opposite confusion... ;) 172.70.91.161 15:36, 8 August 2023 (UTC)

I ran some calculations on using rechargeable batteries to get power from the Sun to Earth, full markdown file is here is anyone to check it out.

TL;DR: it's way better than running powerlines to Earth but falls slightly shy of putting a panel on Earth, though that may be remedied by more precise data. Xkcdjerry (talk) 15:09, 8 August 2023 (UTC)

New idea: maybe we can make some sort of belt in which one side has fully discharged batteries and the other has fully charged ones, so that gravity balanced out and we only need to do work against friction, that should raise the efficiency greatly, with some engineering we might get it above 0.1% or even 1%, however I don't have exact data on this so this remains the work of someone with more knowledge than me XD Xkcdjerry (talk) 15:38, 8 August 2023 (UTC)