Aussie convection tower to generate 200 MW

[Flatulo]

http://www.enviromission.com.au/project/video/video.htm

This would be the tallest structure ever constructed - 1000 m.

[Captain Angry]

1. Wow, that was interesting.

Not thick on details, but I can see where they're going with it.

We could stick something like that in Arizona and let it do its thing.

[TheMadMonk]

2. I believe it's on the cards.

Certainly somewhere in the States is getting one sometime soon. (Before ours I believe.) And Ariszona seems as logical place as any.

[Captain Angry]

5. I picked Arizona for a couple of reasons.

The height of the tower doesn't lend itself to places that have higher populations or air traffic.

The ability to grow local produce is something that Arizona doesn't really have.

Etc.

[TheMadMonk]

3. DId you notice the use of the outer portion as a greenhouse?

With proper attention to prevailing high altitude winds and local geography, large numbers of these towers could be used to pump moisture into the atmosphere, after first utilising it for irrigation first. Some types of waste water could be "treated" (evaporated) in the higher temperature center regions. The moisture laden exhaust would through interaction with the local geography (mostly hills) be encouraged to become rainclouds.


My thoughts are that they aren't taking this concept far enough.

Why not wrap apartments around the outside of the structure? That view would have to be worth something. Even from only the 100th floor of a 250 floor plus building. Put in industrial, commercial and retail sectors. Getting around would be either by elevator and walking locally and for larger distances circumferential light rail + large express elevators which stop every 20 floors or so.

Turn the whole thing into a self sufficient community. By merging so many systems which are traditionally isolated in modern society, the potential for cost savings are enormous. Starting with the near elimination of transmission losses, since power is generated 'on site'. The 'commute' while radically altered is reduced to a matter of minutes, the longest to the parking garage and your car, if you ever have to visit the outside world.

Surround the whole thing with forests, and parkland. Perhaps "shelves" every 25 floors or so, for "local" parks and facilities built atop the retail/industrial sections.

And for kicks how about a tethered observation deck held aloft by the wind flow.

[Captain Angry]

4. Sounds like the arcology from SimCity

First thing I thought when I saw your response was "Did you even read my post since that's what I wrote!" Then I realized I pulled it back to just what you read there. Every time I post something like what you wrote, I get dumped on so I just cut it back to the wow statement I made.

So, I totally agree. The greenhouse aspect, the evaporative cooling, the self sufficiency, etc. It could be taken to a very interesting extreme.

When I saw the first 30 seconds of that video, I thought the shiny stuff at the base was solar panels for additional power generation. When they went underground to show the greenhouse I got very excited.

[XemaSab]

6. I doubt it could really be used as a greenhouse

I think the trees were just there for scale.

My understanding of how it works is that the glassed-in portion traps heat (up to 158 degrees), which naturally rises to power the turbines. It would have to be sealed, clear glass, and it would get really hot. Plants need air and in greenhouse conditions, indirect light. That's why greenhouses are painted white. Also, if it wasn't sealed, the air would go out the sides.

They could probably increase efficiency by siting it somewhere with dark soil/rocks.

I'm wondering what happens at night here. Does it run backwards? :shrug:

Also, this isn't very much power for the scale of the thing. There are currently plans to build solar thermal systems here for 500 and

Existing solar thermal plants have outputs of around 80 MWh. Build a few "conventional" solar thermal plants and you've accomplished the same ouput.

[TheMadMonk]

7. Much, much lower temp at the perimeter.

edit to add: It's the temperature differential between the rim and the hub that drives the thing.

At night it continues to run on the thermal potential of the air under the glass.

[XemaSab]

8. What creates the temperature differential?

It looks to me like the thing operates like a giant steam turbine without the steam. :shrug:

[TheMadMonk]

10. Sunlight.

The longer it spends under the glass (moving towards the middle) the more it is warmed by the sun.

[XemaSab]

12. Well DUH...

I'm asking why different parts of the glassed in areas are different temperatures, and I'm not buying that the air in the middle has spent more time being warmed. The air on the edges is part of the same trapped-in space.

[TheMadMonk]

14. Get out you're wallet. You're buying.

The air is not static, it's in motion. It enters at the rim at ambient temperature. And passes through the turbines at the hub, some 30-40 degrees hotter.

[XemaSab]

15. What keeps it from going back out the way it came in?

:shrug:

[tinrobot]

16. The chimney.

Once the air stars flowing up the chimney, it pulls new air into the system.

In many ways, it acts pretty much like the chimney in your house. The hot air creates it's own draft which pulls new air into the fire. In this case, however, there's no fire to heat the air, just a lot of glass.

[philb]

9. Has there been a prototype? Is there some reason to think it will be cost effective?

We know hot air rises, and enough hot air with sufficient temp. differential could turn turbines.
But this structure looks pretty capital intensive, why do they think it would produce enough power to pay back?
Anyone aware of the background of this and previous studies or pilots on it?

[TheMadMonk]

11. A 200m pilot plant has been built in Spain.

I believe it performed beyond expectations. But because of the way this design scales, bigger is most definitely better.

[skids]

13. Actually they downscaled from "friggin huge" to "big"

They did the math after having some engineers go at it and found that four towers 1/4th the size (of the original design, still > 200m) was where the point of diminishing returns sat, given current construction technology.

As the when this will ever get off the ground, it is anybody's guess. They've been very slow about it.