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Another Do it yourself cooling option

DIY low budget cooling idea

In searching for more low budget do it yourself cooling options I came upon this cooling tower design.

It seems like one of the more expensive solutions out there, but might end up saving money in the long run. The tower should be at least 6 feet square, 20 to 30 feet tall with as much insulation as you can muster.

I wonder if this concept could be scaled down for just one room instead of an entire house?

Image credit goes to the thefarm.org which has a well written article on this method of sustainable cooling. They've also got a good section on permaculture in Tennessee.



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I would think that if you live in an area with high humidity it would be a bad idea to add even more moisture to the air. You would be living in a cool, damp, house.
Comment by zimmy Sun Jul 11 22:31:42 2010

Look into the design of the old North African Souk architecture. My last house was designed on the principles they employed... opening sky lights, casement windows able to catch a tiny breeze from any direction, open air flow... and we found that we only wanted AC when we messed it up by adding a 2nd floor with poor circulation and no tree cover.

It's way cheaper, and prettier, than a solar chimney.

Comment by April Mon Jul 12 07:18:48 2010

Very good point, Zimmy. I think Roland's idea (if it was his) from a few weeks back about using water to cool air in a separate chamber so that it decreases humidity would be a very good tweak to this design.

April --- we'll have to look into that! I also was recently reading about a whole house fan --- intriguing idea. Of course, if we're going to do anything pricey, Mark wants to just build a hobbit hole in the side of the hill and use the coolness of the earth, but that plan is a few years off.

Comment by anna Mon Jul 12 08:31:46 2010
You may not realize it, but you had a whole house fan growing up. The fan in the front window blew out, drawing air in wherever a window was open in any room. This works in a well-sealde small house. In larger houses a fan exhausting into the attic does the same thing.
Comment by Errol Mon Jul 12 15:05:31 2010
We have a whole house fan here and it's great! Loud, but great. I suspect the noise has more to do with the poor quality of construction of everything around here than the house fan itself... but to be on the safe side don't put it right outside your bedroom door.
Comment by April Mon Jul 12 15:17:40 2010

Daddy --- my understanding is that whole house fans are more than that. The ones I've read about exchange all of the air in the house with the outside air in just a few minutes. So, you could turn it on around dark, and turn it off half an hour later for a house completely cooled to exterior temperatures.

April --- Loud isn't really a problem --- Mark loves fans and turns them on at night to sleep by even when he doesn't need them. I'm glad to hear it works so well for you! I just ran across the concept recently, and it sounds wonderful.

Comment by anna Mon Jul 12 16:56:22 2010

Evaporating water takes a lot of energy (2257 kJ·kg⁻¹), so it is a quite efficient way to cool stuff. But unless you are in a very dry climate I would rather use a cooling tower to cool water that is then used to cool air via a heat exchanger. Unless you're fond of a wet indoor climate and growing mold in your living room, that is. :-)

A solar chimney with a geothemal heat exchanger might work equally well in your case. Conceptually, the solar chimney in this case is just a "ventilator", but without electricity or moving parts. Quite appealing from an engineering point of view, because of its simplicity and the fact that it uses the sun to get rid of unwanted heat.

An related technology that you might find interesting is a solar updraft tower for generating electricity. A 50 kW max. power prototype was operated in Spain for about 8 years.

If you ever think about building an underground house, go and talk to an architect and/or a building engineer, for both structural integrity and heat flow management reasons! A layer of earth is quite heavy, especially when wet. In a relatively temperate environment like yours your house will probably require quite a lot of insulation and waterproofing (next to the earth walls) to prevent it from getting too cold and wet. See the "potential problems" section in the earth sheltering article.

A passive solar building design might also be an alternative. The linked article touches on the factors involved. It's not really difficult IMO, but it does require some physics/engineering background knowledge.

Comment by Roland_Smith Mon Jul 12 17:08:12 2010

Anna, how long a whole house fan takes to cool a house depends to a large degree on how big the thermal mass of the house is and how well the walls give off heat.

To use an equivalent example of emptying a tank of water through a hole in the bottom; the larger the tank (thermal mass) the longer it takes to empty. The smaller the size of the hole (better isolation of the walls) the longer it takes. Of course the opposites also apply.

Comment by Roland_Smith Mon Jul 12 17:25:55 2010

We did retrofit our trailer for passive solar heating, and our wall of south-facing windows gives us quite a bit of winter heat. I think we should probably extend the overhang just a tad, but we only get unwanted sun in those windows for a couple of weeks per year.

On the other hand, we have big windows on the west side of the trailer which are a pain in the summer. We need to get our act together and plant something there to shade them, or just make some kind of blinds to block the sun when it's low in the sky.

Comment by anna Mon Jul 12 19:09:43 2010

One very unique homestead, $1,500 per acre, the opportunity of a lifetime