Cheaper means of air-conditioning by using gunny bags and sprinklers. Any takers?

Question

Few years back, I saw a documentary on using gunny bags and sprinkers for an effective and cheap air conditioning mechanism. The gunny bags, used on rooftops hold water sprinkled by the sprinklers for sometime and finally evaporate due to heat. The evaporation pulls out additional heat from the roof thereby making it cooler. This mechanism is quite effective in tropical and mediterranean countres. Additionally the process involves no heat exchange mechanism used by airconditioners thereby laying to rest the fear of freon leaks or ozone damage. There certainly are more methods of cooling (or heating). Anybody interested in discussing?

Answer 1

Certainly cheaper easier on the environment but requires more water than we have at present to use esp here where there's a drought and some pretty strict water restrictions-now if there were a way to compensate lack of water for can't combine both-water would short air conditioning with possible fire-not sure.But if one lives in area where water is plentiful when cooling is needed then great remember the Romans used underground pipes(beneath the floors).

Answer 2

This does work, but on a limited scale and not reliably 24/7; because it depends on the evaporation of water to affect cooling, you're heavily dependant on the temperature and humidity of the air passing through the gunny sacks; in highly tropical climates or near the ocean, it won't work as well because the humidity prevents much of the water from evaporating. It's best in hot, dry places, where rapid evaporation can remove a lot of heat, but you go through a lot of water.

This is why refrigeration and HVAC units are rated in tons -- it's actually a measure of how many tons of ICE would be equivalent to the cooling effect of the AC unit. In many places, you just can't replace a freon cooling system with anything else; the best you can do is replace the freon with a less environmentally-harmful compound (Hydrofluorocarbons are more expensive, but do not have the chlorine atom that is the main culprit in ozone depletion) and design it to run more efficiently.

Answer 3

I also read something about them, not quite the same materials, but that is what is known as a "swamp cooler" mists are mixed with incoming air, once the air is cooled, another process removes the moisture from the cooled air, and the air is then sent into the house. It is best used in dry regions as the amount of moisture int the air (humidity) will limit the amount of evaporation, hence cooling. As for the gunny sack cooling while it might work in prinsciple, the burlap would quickly become a fertile surface for molds, mildews, and bacteria to grow on.

Answer 4

In Phoenix, I was in an outdoor restaurant area and I noticed some pipes above us creating a mist. Interesting. Then I figured out it was this form of air cooling that you refer to. It works, just as human sweat does for our bodies.

This only works in dry climates, if you are in a humid climate it's not as good. Also, It really wont work indoors much, since a lot of the AC 'comfort level' is reducing humidity as well as temperature. Going from a dry 80 degrees to humid 75 degrees wont feel like 'cooler' to most people.

So, I think in the US it may stay limited to being a possible outdoor AC mechanism in dry places like Arizona!

Answer 5

That is kind of like a home made swamp cooler. But it does not work that well in humid areas since the high humidity reduces evaporation. It works best in the dry hot desert, where water is scarce.

Answer 6

Try the solar cooking discussion group (they also discuss things like alternative cooling) or think cycle or the Yahoo group ROE2.

Answer 7

that is a very noble thought.
you are too intelligent for me to discuss anything. but, i wish you all da best...

Answer 8

why don't you start a discussion group on Yahoo groups?