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Heliogen targets 1500°C solar thermal

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Re: Heliogen targets 1500°C solar thermal

#61

Post by thinkcontext »

baybal2 wrote: post #56
thinkcontext wrote: post #38

Earlier quoted context omitted.

Here's a better article which explains the advantages over traditional CSP. https://www.vox.com/platform/amp/science-and-health/2019/11/... TL;DR Traditional CSP is aligned once, Heliogen aligns continuously. This allows them to correct for individual panel changes in warping, settling, weather, dust, etc. This approach also allows them to use cheaper hardware.

Well... no. Motors and circuitry on each mirror instead of a simple screw drive are certainly not making the setup cheaper It smells to me like a second Solindra in making

You didn't bother to read the article.

> Rather than assembling large, complicated, curved heliostats (mirrors) on site, eSolar used small, flat, prefabricated heliostats of only about a square meter. They were cheaper, faster and easier to set up, more modular, and easier to replace.

> Gross’s key insight was that he could replace a lot of the material and labor involved in CSP with computing power. (Or, he could replace stuff with intelligence.) Rather than make bigger, more complicated mirrors, he made small, simple ones and controlled them with software, so they stayed aligned more precisely and produced more power.

Re: Heliogen targets 1500°C solar thermal

#62

Post by baybal2 »

thinkcontext wrote: post #61
baybal2 wrote: post #56

Earlier quoted context omitted.

Well... no. Motors and circuitry on each mirror instead of a simple screw drive are certainly not making the setup cheaper It smells to me like a second Solindra in making

You didn't bother to read the article. > Rather than assembling large, complicated, curved heliostats (mirrors) on site, eSolar used small, flat, prefabricated heliostats of only about a square meter. They were cheaper, faster and easier to set up, more modular, and easier to replace. > Gross’s key insight was that he could replace a lot of the material and labor involved in CSP with computing power. (Or, he could re…

> You didn't bother to read the article.

I did, their entire premise is invalid. They are either very bad at math, or engineering, or both.

The metal part, screw drive, and simple pulleys and etc are nor hard, nor expensive. Saying it otherwise is purest bs.

The limits of precision of theodolite are more than enough position for precise initial reference.

Existing solar thermal farms were not designed for generation of process heat in mind to begin with, so them saying that they suck at that because of their "design" is a PR trick.

Existing thermochemical processes are profitable enough to burn oil for them, and if one minds anything cheaper, they will first consider CHP colocation before thinking of anything as weird as this.

Re: Heliogen targets 1500°C solar thermal

#63

Post by nradov »

trickstra wrote: post #32
tempodox wrote: post #30

Inertia must be incredibly strong. Otherwise, why did it take so long to come up with something that strikingly simple? The last time someone allegedly had an idea like that was around 212 B.C., in the defense of Syracuse.

Because of oil lobby mostly. The idea is nothing new, it was just easier to burn oil instead of building new industry from ground up and going against all existing oil companies.

That "oil lobby" conspiracy theory is such nonsense. There are several developed countries with minimal oil reserves and no domestic oil companies. If alternative energy industries were really practical before then those countries would have built it.

Re: Heliogen targets 1500°C solar thermal

#64

Post by smueller1234 »

JshWright wrote: post #27
pjc50 wrote: post #23

Earlier quoted context omitted.

The difficult problem is not knowing where the sun is but knowing where the ground is. Since all the panels are separate structures not on a single rigid slab, ground "settling" can tilt them fractionally in unpredictable ways. It sounds like what they have is machine vision as a novel input into a conventional control loop. For one panel at a time, wiggle it about and look how the light spot changes. Find the local…

From my comfy armchair, with zero experience in this field, it seems like you could use star tracking to very accurately predict the angle of the sun (since the sun is effectively fixed in position relative to the background stars over the timescales you'd care about). Spotting the target is a little harder, but the same measurement could be made by sticking some reflectors in known positions around the target. I'm s…

Many years ago, I implemented star tracking for telescope alignment for auger.org. An actual basic version using libnova et al was pretty straightforward and a matter of days to prototype if I recall correctly (it was a project for a master student, so I had to do most of the work over a longer period of time). I think the accuracy was around a decimal fraction of a degree then. But the cameras of that thing have only 440 1.5° pixels (photomultipliers that sample at 5-20M samples/s). A higher resolution camera could probably do much better assuming you have a very accurate computer model of the optical properties of your telescope/lenses/camera.

Re: Heliogen targets 1500°C solar thermal

#65

Post by dang »

thinkcontext wrote: post #38
Juliate wrote: post #3

https://en.wikipedia.org/wiki/Odeillo_solar_furnace "started operating in 1970", "Temperatures above 3,500 °C (6,330 °F) can be obtained in a few seconds". See also https://en.wikipedia.org/wiki/Solar_furnace Not dismissing this press release, but at least some scale of progress should be used to compare against. Or state where the economical/industrial/regulatory innovation stands.

Here's a better article which explains the advantages over traditional CSP. https://www.vox.com/platform/amp/science-and-health/2019/11/... TL;DR Traditional CSP is aligned once, Heliogen aligns continuously. This allows them to correct for individual panel changes in warping, settling, weather, dust, etc. This approach also allows them to use cheaper hardware.

Ok, we've changed to that URL from https://www.theengineer.co.uk/bill-gates-heliogen-solar-ther.... Thanks!

We'll keep the original article's title, since it's more specific.

Re: Heliogen targets 1500°C solar thermal

#66

Post by dreamcompiler »

JshWright wrote: post #27
pjc50 wrote: post #23

Earlier quoted context omitted.

The difficult problem is not knowing where the sun is but knowing where the ground is. Since all the panels are separate structures not on a single rigid slab, ground "settling" can tilt them fractionally in unpredictable ways. It sounds like what they have is machine vision as a novel input into a conventional control loop. For one panel at a time, wiggle it about and look how the light spot changes. Find the local…

From my comfy armchair, with zero experience in this field, it seems like you could use star tracking to very accurately predict the angle of the sun (since the sun is effectively fixed in position relative to the background stars over the timescales you'd care about). Spotting the target is a little harder, but the same measurement could be made by sticking some reflectors in known positions around the target. I'm s…

Figuring out the sun's location is the easiest part of the problem. The hard part is that each mirror is a big, floppy slab that moves with wind, temperature, gear backlash, mechanical wear, rain/hail, and ground settling.

The so-called "AI" here is really just a clever way to use closed-loop control so that the above factors don't matter much.

(Side note: A large amount of "AI" these days just amounts to changing open-loop mechanisms to closed-loop, often by using computer vision as the state sensor. 3D printers, for example could become much more precise with no mechanical improvements if they did this. Probably some have already done so.)

Re: Heliogen targets 1500°C solar thermal

#67

Post by giarc »

newnewpdro wrote: post #59
giarc wrote: post #33

Earlier quoted context omitted.

I recall seeing a chart one day that showed bird deaths by source. Death by domestic cats were magnitudes higher than any other source.

The Mojave desert wilderness areas are not overrun with domestic cats. 6000 sounds like a lot to me. I have five acres near joshua tree, and while there is wild life the only stuff that seems to be abundant are some rodents, rabbits, and reptiles. It's a fragile ecosystem. There used to be tortoises supposedly, but the roads wiped them out.

The devils advocate view is that climate change will kill them all, so what's really that bad about 6000 birds?

Re: Heliogen targets 1500°C solar thermal

#68

Post by rrss »

rasz wrote: post #55
pjc50 wrote: post #23

Earlier quoted context omitted.

The difficult problem is not knowing where the sun is but knowing where the ground is. Since all the panels are separate structures not on a single rigid slab, ground "settling" can tilt them fractionally in unpredictable ways. It sounds like what they have is machine vision as a novel input into a conventional control loop. For one panel at a time, wiggle it about and look how the light spot changes. Find the local…

CD-ROM laser pickups have been doing it in the 70s without AI.

> what they have is machine vision as a novel input into a conventional control loop

Control loops are everywhere, but CD-ROM drives do not use machine vision. That's why op said that's the novel part.

Re: Heliogen targets 1500°C solar thermal

#69

Post by rrss »

ReptileMan wrote: post #50
pjc50 wrote: post #23

Earlier quoted context omitted.

The difficult problem is not knowing where the sun is but knowing where the ground is. Since all the panels are separate structures not on a single rigid slab, ground "settling" can tilt them fractionally in unpredictable ways. It sounds like what they have is machine vision as a novel input into a conventional control loop. For one panel at a time, wiggle it about and look how the light spot changes. Find the local…

I may be dumb, bit don't we have pretty simple and reliable gyroscope based solutions to this problem.

Gyroscopes drift. Every system using gyroscopes that needs precision has some external tracking system as another reference (e.g. GPS, star tracking). In this case, that external system is a camera on top of the tower.

Re: Heliogen targets 1500°C solar thermal

#70

Post by agumonkey »

astrodust wrote: post #52
agumonkey wrote: post #43

Earlier quoted context omitted.

I wonder how security is handled there

Oh man what if someone stole the sun . (In all seriousness, the security risks are pretty low here. This isn't like stealing nuclear fuel.)

Sorry I meant safety.
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