Solar Chimney & Cooling Towers
SUBSIDENCE TOWERS
Introduction
The Visitor Centre at Monarto Zoological Park uses three subsidence towers for cooling the public and administrative spaces. The subsidence towers are 3.6m x 3.6m with an overall height above floor level of 9.4m.
The subsidence towers at Monarto are believed to be the first installed in Australia and will demonstrate an alternative low energy, low water consumption model for cooling in hot arid climates.
Purpose
The purpose of incorporating the towers into building designs is for space, air, comfort condition in arid climate locations.
Subsidence towers introduce moisture at tower top by air filtration through controlled rate wetted perimeter pads, the increased air mass within the tower propelling the air volume into the building.
Tower operation utilises these naturally occurring air movement forces and thereby minimises both water and energy demand. Energy demand is limited to water pumping from storage to the tower head. Water use is regulated to maintain wetting of pads released by evaporation with minimum excess water discharge. As the tower is large in duct volume, significant air changes are generated with low perceptible air movement speeds which avoids the chill cooling more common with duct and fan forced systems.
Background
Similar evaporative systems have been used at times over the centuries in Middle East and Asian locations with arid climates. In modern mechanised societies, fan forced, package evaporative air conditioners have become standard.
In the mid-1980s the University of Arizona, U.S.A. through its Environmental Research Laboratory, trialed a formal tower construction which was subsequently installed on successful trial for space conditioning of a public shopping centre pedestrian plaza in Phoenix.
In the late 1980s a detached residence was built (Thompson & Cunningham) incorporating both a thermal chimney and a downdraft tower. This tower was monitored for performance, and this was subsequently computer-modelled at UCLA. The University of Arizona has published a number of abstracts on their work and the Thompson & Cunningham installation. This is summarised and extended on by Professor Baruch Givoni of UCLA in his book Passive and Low Energy Cooling of Buildings.
Phillips and Pilkington Architects together with a consultant architect for the Monarto Visitor Centre, Emilis Prelgauskas, designed and documented the towers using knowledge and expertise drawn from his previous work and study. The result is a modern, practical application for an ancient climate control design.
The Monarto Visitor Centre subsidence or "cool towers" are believed to be the first to be constructed and used in a commercial application anywhere in Australia.
http://www.adelaide-zoo.com.au/
I. Solar Chimney's - web site
II. Cooling Towers - web site
III. Combine Cooling Tower/Solar Chimney structure
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I. Solar Chimney's
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There's a picture of a solar chimney at:http://www.me.ufl.edu/SOLAR/sc.htm
and diagrams at http://www.argonet.co.uk/users/bobsier/sola6.html
Nick Pine, who I think has been involved in strawbale greenhouse concepts, wrote a neat article on them with some CALCULATIONS at:
Sustainable Building Sourcebook has some conceptual Online drawings at:
http://www.greenbuilder.com/Sourcebook/PassSolGuide3.html
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II. Cooling Towers
===========================This Url has a neat drawing of a cooling tower and gives the best description and theory of a real-world cooling tower which I've seen - it uses a swamp cooler.....
http://stores.us.ohio-state.edu/%7Esteen/homepower/
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III. Combine Cooling Tower/Solar Chimney structure
=========================================I live in the desert and cooling is a big concern of mine. I've read where air cooling requires ventilation, passive is good, but swamp coolers don't require much electrical energy especially in comparison to air conditioner units.
I also read, that strawbale houses can be heated with small electric heaters in the winter time because the insulation is so good.. However, in the summer time, I'm worried that it can be tooo good.... I've read that even using stoves/ovens/refridgerators/freezers can really warm up the inside.
I recognize that the hot air needs to be vented out. Again the need for ventilation.
The solar chimney, is great for providing ventilation. It works on the principle that hot air rises. So, U use glass (clear sides) on 3 sides, black on the other, and use metal lath to absorb the heat. The heated air rises creating ventilation. U would want this thermal chimney attached to the outside (or separate from your house). The solar chimney was not designed for cooling per se, but for making "wind" to drive "windmill type blades. This can be done to generate electricity as an added benefit, but that's off-topic. Another bad poiint is that one needs to build a tower...
While drawing hot air out is good, we still need to draw cold air in. Swamp coolers are great (don't put them on your roof tho) for dry climates, but even so, there are a couple weeks out of the year that it just doesn't cut it here in Las Vegas mon. So that's why I have been investigating cooling towers. The one in the URL above, uses a swamp cooler, but has it at the top of a cooling tower and thereby greater cooling is achieved. The cooling tower in the URL, had a rather complicated mechanical system for directing the outside wind into the swamp cooler. Why? Because more ventilation means cooler air. Being more electrically minded, I didn't like that mechanical thang. Simular to a Solar chimney, the cooling tower requires a tower.
SO I figure, if you're gonna build a tower, why not put both a cooling tower and a solar chimney into 1 structure. This structure would have 2 separate chimneys - 1 for the cooling tower, and 1 for the solar chimney. The swamp cooler pushes that cool air down to the house thru vents in the cieling (as is done in my house). In my house, as in most houses which use swamp coolers, I open a window or two and this is where the air leaves the house. However, instead of opening windows, we open a door into the solar chimney.
U could also draw air from the output of the "cool pipes" (talked about in some posts a couple of months ago) in a fashion simuliar to that shown in a diagram, in figure 7, in the Sustainable Building Sourcebook URL above.
Any comments on the above would be greatly appreciated...
Regarding the water wall concept that Bill Christensen mentioned, there is a tile wall like that at a famous tourist trap called Scotty's castle in death valley. It's a fun place to visit - in the winter time. It has water running down the tile face from a copper tube with holes in it just above the tile. The water enters a small concrete looking pool with a drain pipe. The water comes from a year-round creek (I think), but it may be recirculated for all I know...
I could go into my cool septic tank idea again, but....
DTT
http://www.crest.org/efficiency/strawbale-list-archive/9701/msg00532.html
Info:http://www.ccom.lk/energen/index.html
http://mudhole.spodnet.uk.com/~imp/venice/solar.html
http://www.sbp.de/solar/aufwind/index.htm
http://www.argonet.co.uk/users/bobsier/sola6.html
http://www.me.ufl.edu/SOLAR/sc.htm
http://home8.swipnet.se/~w-89663/energy.html
http://wwws.us.ohio-state.edu/~steen/homepower/41p038.html
http://design.gateway.net.hk/gluck/SolarChimney.html
http://hilbert.anu.edu.au/~kreetz/AbstractDiploma.html
http://www.fujita.com/fruk/NewsArchive/ehNews0310.html
http://www.munichre.com/publications/report97/large_scale_eng.htm
http://www-klima.bauwesen.uni-dortmund.de/public/nolte1/
2002/08/19: Guardian(UK): Real power from nothing but hot air -
Australia plans 1km-high convection tower to supply 200,000 houses
http://www.guardian.co.uk/australia/story/0,12070,776776,00.html
2002/08/19: New Scientist: Kilometre-tall power tower approved
http://www.newscientist.com/news/news.jsp?id=ns99992688
http://www.enviromission.com.au/index1.htm
http://www.aie.org.au/pubs/enviromission.htm
http://bulletin.ninemsn.com.au/bulletin/eddesk.nsf/All/A7BD712D34AE25B3CA256B12001BA833!open
http://www.eyeforenergy.com/print.asp?news=31448