Electricity from down drafts

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EatenByLimestone

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This idea has been around for quite awhile, the capital cost is significant and the water requirements in an arid climate also is an issue. Both can be handled with enough money. The same project was proposed for Australia a few years back when the government offered big subsidies. The subsidies got pulled so the developers moved it to the US
 
Yes, I would want to examine the water loss numbers very closely. We are running out of water in the southwest and other desert regions. And this will get worse with higher evaporation rates caused by increasing ambient temperatures there.

There was another project that I followed several years back that is similar but works on updraft instead. No water needed. They did a successful pilot test in Spain and were going to build one or more huge towers in Australia, but the project never got off the ground there. Then it was proposed for Ariz. Not sure how or if it is progressing. There is also one in Mongolia,

http://en.wikipedia.org/wiki/Solar_updraft_tower

My younger son and I worked on testing this principal for a science fair project. The results weren't stunning, but we were able to get the chimney to pull using solar heat.
 
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I used to have a 300 foot stack at my place of work, Even when the boiler was down for several days, opening the door at the base of the stack would suck a hard hat off.
 
There's a lot of power potential in a tall stack's updraft.
 
IIRC the solar tower concepts came in at ~1% conversion efficiency. I wonder what the downdraft towers come in at in terms of net kWh/kg of H2O
 
It is less efficient, but cheaper too. This paper goes over the pros and cons of may technologies.

4.1 Advantages of the Solar Chimney-Concept
The glass collector uses diffuse and beam radiation
the soil under the collector acts as heat storage, avoiding sharp fluctuations and allowing power supply after sunset
easily available and low cost materials for construction
simple fully automatic operation
no water requirements.
4.2 Disadvantages of the Solar Chimney-Concept
Very low solar to electricity conversion efficiency
hybridization is not possible
equivalent full load hours restricted to approximately 2500 h/a
large, completely flat areas required for the collector
large material requirement for the chimney and for the collector
very high chimneys necessary for high power output (e.g. 750 m for a 30 MW plant).

http://web.archive.org/web/20070615...b.cern.ch/jgalvez/Solar/Articles/TRIE0179.pdf
 
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