Solar updraft tower: How small a working unit can be made?

[jab]

solar updraft tower: How small a working unit can be made?
My reason to ask this question is:
I think that if a commercial unit is ever to be built, first the concept must be widely established.
One or two working examples of a size similar to the prototype built in Spain won't likely prove commercial usability. The huge billion dollar concepts are way too much money to sink into a radical concept. Small inexpensive home electrical generation projects may actually be built.
So how small a chimney will work? Could multiple chimneys be arrayed together? How many in an array? Could the chimneys be built around a house or barn? Could the array of chimneys be a structure wider than it is high? How inexpensively could this type of power generation system be built when scaled for a single average home? Could the tower height be kept within suburban housing bylaws limits?

I don't know about you, but I would rather see a photo of somebody's working backyard ugly kludge,
than the most beautiful digital animated movie of a solar thermal updraft tower mega-project.

 

[stewartcs]

solar updraft tower: How small a working unit can be made?
My reason to ask this question is:
I think that if a commercial unit is ever to be built, first the concept must be widely established.
One or two working examples of a size similar to the prototype built in Spain won't likely prove commercial usability. The huge billion dollar concepts are way too much money to sink into a radical concept. Small inexpensive home electrical generation projects may actually be built.
So how small a chimney will work? Could multiple chimneys be arrayed together? How many in an array? Could the chimneys be built around a house or barn? Could the array of chimneys be a structure wider than it is high? How inexpensively could this type of power generation system be built when scaled for a single average home? Could the tower height be kept within suburban housing bylaws limits?

I don't know about you, but I would rather see a photo of somebody's working backyard ugly kludge,
than the most beautiful digital animated movie of a solar thermal updraft tower mega-project.

Pretty sure there are commercial ones already out there. I seem to recall some discussions here years ago about one in either the middle east or Australia? I don't think the economics are they now which why they're not more around. Fossil fuels are too cheap (especially recently).

CS

 

[256bits]

too much money to sink into a radical concept

It's not radical - the chiminey draft effect has been known for ages.

It is the cost of the tower and the size (cost ) of the land needed for solar heating of the air.

What you are doing is using the energy of the sun to heat air to make it buoyant causing a pressure difference between the top of the tower and the bottom. So there is a trade off between height of tower and solar collection area to get the same power output. Either way, both add to the upfront capital cost of the project.

 

[Baluncore]

jab, welcome to PF.

The minimum economic sized tower would need to be a couple of hundred metres high. It would not be sensible to build a solar updraft tower over a house or barn because of the noise and wind damage caused to the buildings. The technology is quite incompatible with suburban housing regulations.

 

[anorlunda]

The visitors center at Zion National Park is cooled by such a tower. It is of reasonable size.

 

[Baluncore]

The visitors center at Zion National Park is cooled by such a tower. It is of reasonable size.

That is a short evaporative cooling tower. An evaporative cooler at the top cools air at the top that then sinks down the shaft to cool the interior of the building as it flows out. It has the opposite flow to a solar updraft tower.
http://www.nps.gov/zion/learn/nature/upload/DOE Brochure.pdf