Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Heliogen targets 1500°C solar thermal

vox.com

Post reply on HN
Print view View original

11–20 of 76 posts

Re: Heliogen targets 1500°C solar thermal

#11

Post by viraptor »

ReptileMan wrote: post #10
new299 wrote: post #2

Bill Gross, Heliogen’s current CEO previously founded eSolar. eSolar proposed using an array of Heliostaticly controlled mirrors to direct light toward a solar cell: https://en.wikipedia.org/wiki/ESolar So... that part of the eSolar approach is carrying over into Heliogen. Last time this was posted the “AI” component of the play was less clear... But with an array of mirrors, in particular being to generate heat in s…

What exactly do you need AI for except for buzzwording? It is not as if the sun/earth trajectory or rotation speed is random. You can precalc with ease at every point which is the best position for each mirror.

That did strike me as weird. Although they say "advanced computer vision software" so maybe they do some workaround and take the position from a camera rather than pre-calculations? Can it be the case that a few thousandths of a degree matters here and that's beyond our generalised model?

Re: Heliogen targets 1500°C solar thermal

#12

Post by truculent »

ReptileMan wrote: post #10
new299 wrote: post #2

Bill Gross, Heliogen’s current CEO previously founded eSolar. eSolar proposed using an array of Heliostaticly controlled mirrors to direct light toward a solar cell: https://en.wikipedia.org/wiki/ESolar So... that part of the eSolar approach is carrying over into Heliogen. Last time this was posted the “AI” component of the play was less clear... But with an array of mirrors, in particular being to generate heat in s…

What exactly do you need AI for except for buzzwording? It is not as if the sun/earth trajectory or rotation speed is random. You can precalc with ease at every point which is the best position for each mirror.

Perhaps weather/clouds/objects are a thing that must be adapted to?

Re: Heliogen targets 1500°C solar thermal

#13

Post by TeMPOraL »

viraptor wrote: post #11
ReptileMan wrote: post #10

Earlier quoted context omitted.

What exactly do you need AI for except for buzzwording? It is not as if the sun/earth trajectory or rotation speed is random. You can precalc with ease at every point which is the best position for each mirror.

That did strike me as weird. Although they say "advanced computer vision software" so maybe they do some workaround and take the position from a camera rather than pre-calculations? Can it be the case that a few thousandths of a degree matters here and that's beyond our generalised model?

I'd imagine that the "few thousandths of a degree" is something you'd get worse with AI than with a mathematical model. AI methods introduce noise; with an explicit model you can keep adding complexity directly, until it gets more accurate than your measuring system.

I suspect that the "AI" they mention is mostly photogrammetry - being able to tell the position and orientation of your mirrors from a video stream - in a feedback loop with motor controllers and temperature sensors. Use of cameras would make it close enough to "AI" that the buzzword would stick.

Re: Heliogen targets 1500°C solar thermal

#14

Post by kuu »

truculent wrote: post #12
ReptileMan wrote: post #10

Earlier quoted context omitted.

What exactly do you need AI for except for buzzwording? It is not as if the sun/earth trajectory or rotation speed is random. You can precalc with ease at every point which is the best position for each mirror.

Perhaps weather/clouds/objects are a thing that must be adapted to?

I guess this and also the lack of needing to make a detailed study about the sun position wherever the plant is established.

Re: Heliogen targets 1500°C solar thermal

#16

Post by honopu »

I think the point of calculating using imaging vs a model that requires layout and flat land etc is this would be cheaper to build. You have to build one collection tower/ target, and the mirrors can aim themselves. This greatly reduces the grading, measurement etc and makes installing on existing land without needing to flatten at all, or to some crazy tolerance, much easier. I can see this used in rolling hills, with less impact etc possible.

Re: Heliogen targets 1500°C solar thermal

#17

Post by BurnGpuBurn »

zubspace wrote: post #15

Another similar project in the mojave desert incinerates 6000 birds a year [1]. I wonder, how they handle that.. [1] https://www.sciencealert.com/this-solar-plant-accidentally-i...

I was just wondering how many birds this would fry, thanks for the article.

Re: Heliogen targets 1500°C solar thermal

#18

Post by VBprogrammer »

BurnGpuBurn wrote: post #17
zubspace wrote: post #15

Another similar project in the mojave desert incinerates 6000 birds a year [1]. I wonder, how they handle that.. [1] https://www.sciencealert.com/this-solar-plant-accidentally-i...

I was just wondering how many birds this would fry, thanks for the article.

The problem is generally trivial compared to the number killed by domestic cats and glass windows.

Re: Heliogen targets 1500°C solar thermal

#19

Post by ginko »

reportgunner wrote: post #9
baq wrote: post #6

Earlier quoted context omitted.

yeah the only problem is the useful heat is contained in a very small area/volume, so this is only a research facility.

AFAIK the solar towers actually use molten salts to store the heat in tanks so they can keep going even overnight.

Not sure which salts would be used here, but I 1500C+ is pretty hot even for many salts. Sodium chloride boils a bit below that(1465C) for instance.

Re: Heliogen targets 1500°C solar thermal

#20

Post by kwhitefoot »

zubspace wrote: post #15

Another similar project in the mojave desert incinerates 6000 birds a year [1]. I wonder, how they handle that.. [1] https://www.sciencealert.com/this-solar-plant-accidentally-i...

Is 6000 birds a year a lot? It's a serious question, I have no idea what fraction of birds in the area that is.

Is it comparable to the normal fluctuation in bird mortality in the area or is it so large that it has a disturbing effect on the population?

Of course fewer bird deaths would be good, and zero would be better.

But these bird deaths are noticed because of where they occur. What is the 'background' level, the death rate in the same place without the solar plant?

The Ivanpah installation is on a known migration route, presumably most other such installations will cause fewer bird deaths simply by not being on such a heavily used route. The article was a bit light on background information and I don't know how to find it.

Post reply on HN