[skyemoor]

If you like solar, check out the giga-chimneys they're going to build in Australia (think they might've already built a smaller one in spain).

Solar Power Tower

[strider3700]

actually the heated salt continues to release heat at night so they can work all day.

They work but are costly for their output. They also require areas with very little cloud cover

[sjruckle]

If you read their site, they say that they had expected the underside of the plastic (not glass, as SmokinJuan says) structure to be desert-like, with very few plants. Instead, they report that the plastic traps in heat and moisture, much like a greenhouse. Plants actually thrive under there.

[DarkDawg]

A 3000 ft tower?? The tallest structures in the world today are only around 2000 ft max and they are just radio/tv towers, not heavy structures such as this. The CN tower in Toronto is about 1800 ft if I recall.

I'm no engineer, but this sounds like a pipe dream (no pun intended).

[Aedo]

A 3000 ft tower?? The tallest structures in the world today are only around 2000 ft max and they are just radio/tv towers, not heavy structures such as this. The CN tower in Toronto is about 1800 ft if I recall.

I'm no engineer, but this sounds like a pipe dream (no pun intended).

Those radio towers are built to a height for a specific purpose, not due to engineering limitations. The solar tower is to a sound engineering design which should be challenging, but not impossible, to construct.

[pilferage]

Imho, the best, low cost, application of mirrors would be a variation on the Minto Wheel that was mentioned not too long ago here. Ideally, if you had four parabolic mirrors with ~four square meters of surface area combined, and were located in the southern California desert, then you could probably get an average of 1800-2400 watts from those mirrors during the day.
Since the mirrors/air/wheel are going to absorb some of the energy, and there will be mechanical/conversion losses, etc.... Maybe we'll be lucky to get 10% of the solar energy transferred. But considering how cheap these could be, ~210 watts during the day time would be nice.

[GoIllini]

A 3000 ft tower?? The tallest structures in the world today are only around 2000 ft max and they are just radio/tv towers, not heavy structures such as this. The CN tower in Toronto is about 1800 ft if I recall.

I'm no engineer, but this sounds like a pipe dream (no pun intended).

Those radio towers are built to a height for a specific purpose, not due to engineering limitations. The solar tower is to a sound engineering design which should be challenging, but not impossible, to construct.

I would hate to be the engineer designing that. Let me guess; you saw it on the Discovery channel after the show on the gigantic carbon tube building that was designed to hold a metropolis.

It's theoretically possible to build up to 2500-3000 ft, as far as I know, but prohibitively expensive. Someone planning on wasting $5 Billion to create a "giga-chimney" would be well-advised to just buy 50,000 parabolic solar collectors with sterling engines.

[Devil]

If you read their site, they say that they had expected the underside of the plastic (not glass, as SmokinJuan says) structure to be desert-like, with very few plants. Instead, they report that the plastic traps in heat and moisture, much like a greenhouse. Plants actually thrive under there.

Sorry, I don't believe it, in a searing hot gale, drawn in from the desert, with temperatures reaching 150°C? Unless they are plants brought in by aliens from another galaxy. Your hypothesis defies physics.

[Caoimhan]

What is the atmospheric pressure under the canopy? The whole idea of the chimney is to create a massive low pressure area inside the chimey.

Let's see... insolation through the transparent canopy causes a greenhouse effect under the canopy, increasing temperature.

An increase in temperature would initially cause an increase in pressure.

But the increase in temperature causes the air to rise relative to the cooler air outside.

As the air rises up the central chimney, the pressure under the canopy drops again.

Is the chimney tall enough that the moist air inside the chimney might reach the dewpoint as it rises in altitude? Is it possible that the moisture inside the canopy/chimney might remain there?

[Devil]

I'm sorry, there seems to be a misconception how this works. The Oz project, as I remember it, is a 27 km², roughly circular "greenhouse", open at the outside periphery, where it is lowest, sloping upwards to the 1000 m chimney. The turbines are placed in a venturi at the bottom of the chimney. The whole area has a rough, dark ground and is placed in the middle of the outback desert.

The ground is heated by the solar radiation and this heat is partially transferred to the air in contact with it, causing it to rise in temperature. Convection currents cause it to rise to the highest point, the turbine intake, and up the chimney at ~150°C. With 27 km² of area, the theoretical daytime energy input is about 35 MW and this is transferred to the mechanical and thermal energy of the moving air, some of which is dissipated in the turbine to drive the generators. There is an enormous amount of air moved, so the velocity at the input side is high enough to blast anything in the region.

The outside air averages about 35°C in the daytime with a typical RH of 25%. As there are no significant means in the open space under the canopy of restricting the flow, the pressure is substantially constant at the outside pressure. The dew point depression at this temperature and humidity is about 25°C, meaning that for condensation to occur, the temperature would have to drop to about 10°C in still air, instead of rising to 150°C in moving air, so it is patently obvious that the conditions for plant life to thrive are VERY unlikely to be met and the idea of condensation forming on the windows is preposterous. Even at night, there would be sufficient energy stored in the substrate to keep convection currents running, albeit at a greatly reduced energy.

One of the problems with the concept is how maintenance of the turbo-generator can be performed. I'll leave it to your imagination how any person can survive under those conditions. Another problem is how to keep the windows of the canopy transparent, with the high velocities in a desert (abrasive sand) environment. Convection currents are hardly rocket science, but the practical considerations will not be a sinecure to resolve.

[aldente]

These guys in Germany work on reinventing the good old stirling motor this time with the help of a fancy mirror.
sun machine

[strider3700]

there are a few companies working on stirling motors and parabolic mirrors, It seems like a fairly simple concept so I'm wondering why it's taking years to get a model out.

As for the chimney I'm not sure why they are scaling it up like that. A test one was built in europe in the 90's and it did work. It only produced something like 1 MW though. It was a tall tower but nothing insane like this concept. Why not just build 30 of the small ones that we know can be done rather then try to build one massive structure that can fail. The test tower was destroyed by a storm if I remember correctly.

[Caoimhan]

These guys in Germany work on reinventing the good old stirling motor this time with the help of a fancy mirror.
sun machine

Cool! I'm just glad I read German, because this site doesn't appear to have an English version.

I'd love to see a company produce these things in North America under license to them. Given the lattitude differential (most of Germany is further North than Minneapolis), the Stirling should operate nearer its peak capacity more than in Germany.

I just wish I had the capital and business know-how to do it. Being English-German bi-lingual, it would be a great business for me.

[strider3700]

someone like this?

http://www.stirlingenergy.com/solar_overview.htm

[Caoimhan]

someone like this?

http://www.stirlingenergy.com/solar_overview.htm

No, because SES is in the business of selling to utilities. They're doing a great job at that scale, but I want to see something that can be installed by homeowners in their back yard or on their roof.

The SES dish is a 25 kW rated system, is 35 feet wide, requires some pretty hefty anchors, and would cost a minimum of 30,000 USD

I don't know how much these Sun Machines will cost, but it should be less.

[bonjaski]

100 megawatt of power for 150mill$


http://biz.yahoo.com/bw/060209/20060209005107.html?.v=1

http://www.iaus.com/

"The turbine with the rocket nozzle is so simple; it can be operated almost at will"

"This requirement will continue to increase until 2015, when it reaches 20%"

"
The thin acrylic lens focuses the sun like a huge magnifying glass on heat receivers. The solar collector, in combination with IAUS' bladeless turbine, equals lower capital costs and maintenance, plus higher efficiency. This enables IAUS and its customers to compete with the increasing cost in the fossil-fuel energy market ... with low-cost renewable energy.
"

no i am sure some doomers will tell me,
that we are runing out of glass

[aflatoxin]

Los Alamos labs built an experimental version of this type of system in the 1970's. I drove past it on my way to school every day when I was a kid.

I'm told it worked really well. It was sold at a surplus auction for almost nothing to a guy who deals with used equipment after the experiment ended.

It was, If I remember, a 20 Mw system. Only problem I am aware of was that it used Refrigerant-12 for the for the motive fluid.

[o2ny]

There was another whole thread a few months ago about whether or not these IAUS guys were just a pump 'n dump stock scam with no actual technology to show (their stock is up almost 100% right now)... this deal looks to be a step in the right direction towards legitmacy, but then again- who is the company they are dealing with- Solar Renewable Energy-1 LLC of Nevada? Is that a legit company?

[aahala]

If we could just capture the hot air coming from that company's
website, our energy problems would be solved.

There's nothing wrong with the site, it's functional, but it looks like
something I would whip up in my basement to announce a
home business. It's not anything like a 20-person company would
have.

I clicked thru to look at the stock stats. The TOTAL cap of the
company seems to be $14 million -- the big headline at the top
of their page is about the 3 TRILLION dollar energy possibilities.
Talk about dreaming. BTW, the stock price the last year was trading
as low as 28 cents a share, for a company that supposedly has been
in business 15 plus years.

Also interesting is not only the company claiming to be this
miracle for the energy industry, the part below that talks about
their supreme advanced technology for the fast food drivethrus.
There we have it, a $1 a share company that saves both the energy
and fast food industry. What more could we want?

[NeoPeasant]

the business of IAUS is clearly to dream up BS technology for pump and dump scams
Class action Lawsuit against IAUS

These guys operate of of rural Utah. Not exactly a technological nerve center.