Free airconditioning

[DannyB1954]

I came across this idea that is being used in India to cool the air for free. It seems easy to make, but does take up a large opening and requires a windy condition. It may be perfect for our southwest.
 http://www.eco-cooler.com/
The principal of how it works is explained on the web page.

 

[BradKW]

Ok, so where exactly does the heat supposedly go? This just seems fishy to me...if it weren't for the apparent philanthropic nature of that website, I'd feel sure it was a hoax. Maybe someone who's a bit fresher on the laws of thermodynamics could explain it...

 

[highdesertranger]

there's a whole other thread on the subject, same website. it was started earlier in the week. I don't really see how this would work. highdesertranger

 

[DannyB1954]

I worked in refrigeration for most of my life and I have a theory how this could indeed work. When air is compressed the heat that is in that air is pushed into a smaller area, this raises the temperature. (You can easily see this on any air compressor, the discharge line is hot). if you remove the heat, then release the air the expansion causes a cooling effect, ( the expanding air absorbs heat).

In this case the compression is minimal, but it does exist. The heat of compression would be right at the neck of the bottle where it is fastened to the thing that holds the bottles in place. The heat would thus be transferred from the bottle to it's holder. The air is not only blowing into the bottles, but also on it's holder.

So if the holder was even a little bit warmer than the outside air that is blowing against it, the heat would be transferred from the holder to that air that was blowing against it. Once the heat of compression was removed, and the air left the bottle neck it would expand and absorb heat in the process causing a temperature drop. Maybe only a few degrees, but even that can feel good.

 

[DannyB1954]

The heat of compression would also be transferred to the sides of the plastic bottle. The air blowing against the outside of the bottle would carry the heat off. The harder the wind blows, the better it works. Here in the southwest it can blow pretty hard in the desert. The biggest problem might be the air not blowing from a constant direction. It would have to be blowing directly into the open bottle.

 

[RVTravel]

If it sounds too good to be true...

 

[VJG1977]

Here are several more links to sites reporting on this.

dailymail.co.uk/sciencetech/article-3635710

http://grey.com/apac/work/key/eco-cooler/id/12475/

http://inhabitat.com/this-amazing-b...from-plastic-bottles-and-uses-no-electricity/

http://www.campaignbriefasia.com/2016/05/grey-dhaka-and-grameen-intel-s.html

http://www.grameen-intel.com/news/g...dhaka-to-develop-zero-electricity-air-cooler/

The Grey Group and Grameen Intel Social Business seem above board.

They claim up to a 5 degree C. cooling and that they have been installed in 25,000 homes.

The plans are free and simple.  The material can be gathered for free or very cheap.  If I needed off grid cooling I would give it a try.

 

[ArtW]

well, better than nothing maybe, but cardboard might not be the best material if it rains

 

[rvpopeye]

It wouldn't cost much to make one and try it out.

 

[Mobilesport]

So if this concept works wouldn't you be able to instead install a single say 12 inch diameter tube that bottled necked down to 2 inch and mount it to a 12 volt 12 inch radiator fan and pump air into the bottle neck that leads to the interior?
Fan would be outside.
A variable speed fan to get the optimum flow/compression without overworking the fan.
Btw   I don't see how it would work in a van considering I have a 5000btu ac that pulls heat out of the interior and struggles against the solar heat gain that comes through the walls even with 1 inch of pink foam board on walls and ceiling.

 

[DannyB1954]

So if this concept works wouldn't you be able to instead install a single say 12 inch diameter tube that bottled necked down to 2 inch and mount it to a 12 volt 12 inch radiator fan and pump air into the bottle neck that leads to the interior?
Fan would be outside.
A variable speed fan to get the optimum flow/compression without overworking the fan.
Btw   I don't see how it would work in a van considering I have a 5000btu ac that pulls heat out of the interior and struggles against the solar heat gain that comes through the walls even with 1 inch of pink foam board on walls and ceiling.

I think the design relies on a volume of air passing through all the holes to cool the space. A single funnel might work but it also might take a car radiator fan to push the air into the large funnel. there would have to be a way for the air in the middle of the funnel to give up the heat to the funnel. The fan would also have to blow air past the outside of the funnel to cool it.

The idea is all air has heat energy in it,  even at zero degrees. Heat pumps stop working about 40 degrees F because the amount of heat in the air is getting too small to move. If you push that air into a smaller area the amount of heat remains the same, but since it is concentrated in a smaller space, the temperature goes up. Now if the heat is removed from that space, and the air is allowed to expand again it will cool as it expands. 

Now that I think of it this is exactly the same principle that an inter cooler for a diesel engine works. The turbo pushes the air into a radiator, the air passing through the inside of the radiator is cooled by the air passing over the radiator. It comes out the other end as cooler denser air. The amount of energy to do this may be more than it takes to run an air conditioner.

If you had a strong enough fan, you could push air into one end of aluminium clothes dryer hose, (4" I believe about 15" long), and restrict the output with a much smaller hose,and put the end of that hose into the vehicle. The air comming out of the smaller hose would expand and cool by absorbing the heat removed by the aluminium hose.

 

[DannyB1954]

Mobile sport, I just re read your post, and I believe you are correct. Just make the high pressure hose long enough so that it can give up heat to the surrounding air.


You would also need to keep the aluminium hose out of the sun, like maybe have it under the vehicle. A squirrel cage type fan puts out good pressure. I think I have one in the garage. I have a short piece of garden hose, so all I need to do is go to Home Depot and get some dryer hose. In a day or two I will have a preliminary report for the experiment.

In the winter you could put the same type dryer hose painted black in the sun for a space heater. Might not even need a fan. Lay the painted hose in the sun on the ground,( out of the wind), and run it up the side of the van at it's end and fasten the end to an open window. heat rises.

 

[Mobilesport]

Dannyb1954
Just a thought, ,,,,,
Would aluminium heat sinks help any to extract the heat , you know the ones with fins on them like you see on car stereo amplifiers?

 

[Mobilesport]

After reading this quote from the Inhabitat link.

"The efficacy of the Eco Cooler varies widely based on conditions, but Grey Group reports it has the ability to reduce indoor temperatures as much as 5 degrees Celsius, which is on par with what an electric centrally installed air conditioning system can do."

I'm considering ripping out my central AC and replacing it with some plastic bottles.

NOT! Quite a claim though.

http://inhabitat.com/this-amazing-b...from-plastic-bottles-and-uses-no-electricity/

Guy

Yea , add some insulation to the ceiling and walls and they probably could make ice cubes LOL

 

[sushidog]

And if you believe that I've got some ocean view property in Florida for sale, just south of Key West...

Chip

 

[DannyB1954]

Dannyb1954
Just a thought, ,,,,,
Would aluminium heat sinks help any to extract the heat , you know the ones with fins on them like you see on car stereo amplifiers?

Probably. As long as you are transferring the heat from the compressed air, anything should work. I was thinking dryer hose just because it is aluminium and is fairly cheap. 

The disadvantage to this system, (other than it might take more energy than it is worth), is that you will only drop the air temp a few degrees below the surrounding temp. With an air conditioning unit because the air recycles through the machine, you can get it 20 degrees or more cooler. 

I was just thinking if you were parked somewhere one could face the doors into the wind, prop up a sheet of cardboard, poke some holes, put in some plastic bottles, and have a cooler breeze blow through the vehicle. Because the bottle bottoms are cut out, they would all stack up into a small space when not used.

 

[DannyB1954]

OK so far the experiment is a bust. Maybe I will try a different fan motor, but the best I could get was a 2 degree drop. probably with wind and the original design it will work, but to create the wind takes too much energy. I will play with it some more.

 

[highdesertranger]

hey, I see a prospecting bucket in the third picture. highdesertranger

 

[jimindenver]

A 2 degree drop is proof of concept. Good job.

 

[DannyB1954]

hey,  I see a prospecting bucket in the third picture.  highdesertranger

In my case more like speculating. I have had better luck with a metal detector finding coins and jewelry. 
Haven't found any yellow stuff. There are some gold claims just north of me. I like what Mark Twain said. A mine is a hole in the ground owned by a lier.

If it does well, they will not say, if it does badly, they will tell you it is prosperous. 

South of me there is one old claim. I think they robbed a stagecoach, and needed an alibi for where the gold they sold came from.