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Heliogen targets 1500°C solar thermal

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Re: Heliogen targets 1500°C solar thermal

#41

Post by ovi256 »

TeMPOraL wrote: post #28
ovi256 wrote: post #26

Earlier quoted context omitted.

>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. This. Modern photogrammetry uses computer vision techniques like deep neural nets. It's an amazing advancement. Imagine this problem: having to place a ground vehicle like a wheeled robot at an arbitrary coordinate in a room. The mirror posit…

> This. Modern photogrammetry uses computer vision techniques like deep neural nets. I'm surprised to hear that. What good do DNN do for photogrammetry? Aren't they too unreliable? I only have university course-level exposure to this, most of it spent learning how to compute coordinate systems and transformation matrices from points on a set of pictures taken from different position. I guess DNNs could help with obje…

Look for Deep SLAM or visual odometry papers, such as:

* https://www.youtube.com/watch?v=Ccj1O7yndIk

* https://www.youtube.com/watch?v=eOuonMhEsxI

* https://www.groundai.com/project/df-slam-a-deep-learning-enh...

The Related work section in the DF-SLAM paper is great.

As you intuited, DNNs work great for tracking visual landmarks (better than traditional computed features) between frames. They can also estimate depth from a monocular camera, which is very useful.

A more out-of-left-field idea is training a CNN to directly regress the camera pose (position and orientation) from an image:

PoseNet, https://www.youtube.com/watch?v=u0MVbL_RyPU

Re: Heliogen targets 1500°C solar thermal

#42

Post by epistasis »

Tangokat wrote: post #36

I wonder who Heliogen hired to do their PR. Must be a really good (or expensive) campaign. There is nothing new in high temperatures and the AI part is pure buzzwords.

I imagine that being able to throw around the name Bill Gates is as big an advantage as a good PR firm.

Re: Heliogen targets 1500°C solar thermal

#43

Post by agumonkey »

Juliate wrote: post #7
scoopertrooper wrote: post #4

Earlier quoted context omitted.

That thing is the size of a building though.

Granted. Size and lightweightness are definitely a point - that could be emphasized as a major argument - even the ratio with size & power capacity & heat intensity.

I wonder how security is handled there

Re: Heliogen targets 1500°C solar thermal

#44

Post by gnode »

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.

The technology is fundamentally simple, but not practical on a small scale. There are plenty of large, yet simple projects which nobody cares to invest in because there are better (including more expedient, or proven) alternatives.

CSP requires a large investment compared to PV solar, as it needs to be done at scale to make coolant systems, towers, turbines and generators cost effective. It needs its own large allocation of land, rather than be distributed. It also, like PV solar, has poor temporal availability, so compares badly to fossil fuels, nuclear and hydro.

It has potential to be cheaper than PV, and integrate well with thermal energy storage. It could also be more efficient, if the temperature can be increased (due to Carnot efficiency). However, the convenience and falling prices of PV panels may prevent CSP becoming popular.

Re: Heliogen targets 1500°C solar thermal

#45

Post by semi-extrinsic »

ginko wrote: post #19
reportgunner wrote: post #9

Earlier quoted context omitted.

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.

Even if the surface temperature of the solar collector focus point is 1500C, the molten salt flowing on the other side of that wall must be at a significantly lower temperature in order to transfer heat quickly enough from the small area. Then you will have a thermal profile in the wall, say from 1500 to 1200 C, and furthermore a thermal boundary layer in the fluid, say from 1200 to 800 C.

Re: Heliogen targets 1500°C solar thermal

#46

Post by analognoise »

pjc50 wrote: post #23
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.

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…

You don't need machine vision for that, you can do it with four photodiodes.

That's how it's been done for like 40 years. No vision or "AI" required.

Re: Heliogen targets 1500°C solar thermal

#47

Post by pjc50 »

sambull wrote: post #34
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…

Interesting, and all that is done by some flowers in my yard; I wonder if the flowers are artificially intelligent.

They could be said to be naturally intelligent, yes. However they only have to point at one target, the sun, while the mirrors have to point halfway between two targets, the sun and the tower.

Re: Heliogen targets 1500°C solar thermal

#48

Post by tzs »

pjc50 wrote: post #23
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.

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…

> 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.

Ground vibration might also be a problem, in applications where this is being used to generate heat for some heavy industrial application. Presumably in that cast said heavy industrial application would be taking place nearby, and so could disturb the ground under the mirrors or tower.

Re: Heliogen targets 1500°C solar thermal

#49

Post by ReptileMan »

tzs wrote: post #48
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…

> 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. Ground vibration might also be a problem, in applications where this is being used to generate heat for some heavy industrial application. Presumably in that cast said heavy industrial appli…

That is solved problem with vr reduction in high quality lenses.

Re: Heliogen targets 1500°C solar thermal

#50

Post by ReptileMan »

pjc50 wrote: post #23
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.

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.
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