How to Accelerate Evaporation Question

I am trying to create a solar refrigerator which is roughly based on the Zeer Pot idea and need to a

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How to Accelerate Evaporation Question

#1  Postby jmdraft » Apr 05, 2012 6:54 pm

Hello,

I am trying to create a solar refrigerator which is roughly based on the Zeer Pot idea and need to accelerate water evaporation.
https://www.google.com/search?q=veer+po ... 07&bih=737
I am looking for something that will, chemically accelerate evaporation e.g. possibly one of these:

https://www.google.com/search?q=blue+ic ... 07&bih=737
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Re: How to Accelerate Evaporation Question

#2  Postby campermon » Apr 05, 2012 8:04 pm

You could use alcohol instead of water.

;)
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Re: How to Accelerate Evaporation Question

#3  Postby JoeB » Apr 05, 2012 8:11 pm

Interesting idea, but as far as I can see it doesn't really cool the interior does it? It just slows the heating process via thermal mass and evaporation of liquid water?
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Re: How to Accelerate Evaporation Question

#4  Postby campermon » Apr 05, 2012 8:16 pm

JoeB wrote:Interesting idea, but as far as I can see it doesn't really cool the interior does it? It just slows the heating process via thermal mass and evaporation of liquid water?


In theory, with a good dry wind (or fanning), the temperature could be made quite cold, maybe even cool enough to make ice.
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Re: How to Accelerate Evaporation Question

#5  Postby JoeB » Apr 05, 2012 8:32 pm

Yes indeed, extracting energy via evaporation. Except this seems to use solar energy to accelerate the evaporation which I find a bit puzzling as it would have zero added effect at best right? (added solar energy increasing evaporation through rise in water temperature which absorbs that added energy).
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Re: How to Accelerate Evaporation Question

#6  Postby jmdraft » Apr 05, 2012 8:52 pm

I’m not sure what it does which is why I’m messing with it.
I like, and will try, the alcohol idea.
Earlier today, I got a 40 degree difference between the outside and inside temp.
The little room behind my mountain house is underground and stays between 50 to 60 degrees in summer. Last year, I put ice trays in one of the little Coleman coolers (its supposed to cool 40 below ambient) and it made ice. The evaporative part of this thing is not happening yet (its empty); just the fan. I just checked it; the inside is 78 and the outside is 117……….so who knows.
Tomorrow, I’m going to start putting stuff in the walls to see what the evaporative part does.
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Re: How to Accelerate Evaporation Question

#7  Postby campermon » Apr 05, 2012 8:53 pm

JoeB wrote:Yes indeed, extracting energy via evaporation. Except this seems to use solar energy to accelerate the evaporation which I find a bit puzzling as it would have zero added effect at best right? (added solar energy increasing evaporation through rise in water temperature which absorbs that added energy).


Yes...puzzling...
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Re: How to Accelerate Evaporation Question

#8  Postby campermon » Apr 05, 2012 8:56 pm

jmdraft wrote:I’m not sure what it does which is why I’m messing with it.
I like, and will try, the alcohol idea.
Earlier today, I got a 40 degree difference between the outside and inside temp.
The little room behind my mountain house is underground and stays between 50 to 60 degrees in summer. Last year, I put ice trays in one of the little Coleman coolers (its supposed to cool 40 below ambient) and it made ice. The evaporative part of this thing is not happening yet (its empty); just the fan. I just checked it; the inside is 78 and the outside is 117……….so who knows.
Tomorrow, I’m going to start putting stuff in the walls to see what the evaporative part does.


:thumbup:

Cool house! There is another poster here who's off grid, but I can't remember their name!!! (it'll come back to me).

And also;

Welcome to the forum!

:beer:
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Re: How to Accelerate Evaporation Question

#9  Postby jmdraft » Apr 05, 2012 8:58 pm

If need be I can add a battery to keep the fan going at night but I’ll be at 9000 ft and it gets cold fast when the sun goes down so I probably wont need the battery………….won’t know until I try it up there.
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Re: How to Accelerate Evaporation Question

#10  Postby jmdraft » Apr 05, 2012 9:00 pm

Thanks,

The alcohol could get expensive which would defeat the no bills purpose but its worth messing with on a small scale.
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Re: How to Accelerate Evaporation Question

#11  Postby campermon » Apr 05, 2012 9:03 pm

The poster I was thinking of was Therapod. He started a thread here about how he went off grid;

http://www.rationalskepticism.org/gener ... off%20grid
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Re: How to Accelerate Evaporation Question

#12  Postby turnerj41 » Apr 06, 2012 10:43 am

dont use salts... they work by freezing point depression. The cooler might work, but I think Zeer Pots are not insulated ( except for a damp covering over the inner chamber) . I think it isimportant to not to use just water or alcohol liquid without saturating something that doesnt dissolve; I am thinking that is because you disperse the molecules and avoid excesssive hydrogen bonding, and also the solid that doesnt dissolve will also be a good conductor of heat from the inner surface to the evaporative surface, but depending on your fan and the rate you are evaporating this may not be as important. since you say you have a cellar you might want to have some deesicant down there too since humidity is not kind to evaporation ( if youput the dessicant in the water it will cool quickly, but it has a capacity). It is probably better to get out of the cellar completely but I am not sure, and I think it depends on the temperature and humidity outside versus what it is down there... I do think you will want a shade if you put it outside. I am also not sure on what the optimum temp of the water should be if you have a choice, but I am guessing you wont have much of a choice. I am also contemplating some other things like: the best shape ( we want most evaporative surface area per unit volume coupled with most outer chamber contact with the wind to keep the whole two pot sytem cooler),and whether baffles would help on either the inner or outer chamber ( most likely the outer ). Good luck, any not so costly improvements on this design would be major.
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Re: How to Accelerate Evaporation Question

#13  Postby rainbow » Apr 20, 2012 11:58 am

jmdraft wrote:Hello,

I am trying to create a solar refrigerator which is roughly based on the Zeer Pot idea and need to accelerate water evaporation.
https://www.google.com/search?q=veer+po ... 07&bih=737
I am looking for something that will, chemically accelerate evaporation e.g. possibly one of these:

https://www.google.com/search?q=blue+ic ... 07&bih=737


Have you looked at the Einstein design?
http://phys.org/news141581384.html
Kill the Wise One!
http://www.southparkstudios.com/clips/155419

"Það er ekki til betri tími en núna til að fresta"
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Re: How to Accelerate Evaporation Question

#14  Postby Ultimate » Apr 23, 2012 12:06 am

I read a bit about the standard models. There are a number of materials that are very porous and thus would be very conductive to evaporation, on the flip side they may not insulate as well. Assuming you have a normal shaped pot you could increase evaporation by increasing the surface area. Maybe by making a wire frame you could drape the towel on to make a teepee like shape. This would have the problem in which gravity would pull the water down, though if you created a drip system that created an equilibrium so the towel remained damp all the way to the base without dripping I think that could work. If you're using batteries I'm pretty sure I can figure out a better way to do that.

The link above is an interesting idea. It looks like you need to use ammonia though. If you were to just buy standard refrigerant I think you could do more with it, I'll have to look into this more thoroughly.
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Re: How to Accelerate Evaporation Question

#15  Postby Made of Stars » Apr 23, 2012 3:40 am

turnerj41 wrote:dont use salts... they work by freezing point depression.

Salts might be helpful in water-based systems where you want to avoid freezing, and the problems that brings. Keeping the system in a liquid phase does allow for circulation, further evaporation and so on. It would bring it's own problems too, of course, such as corrosion.

Addit: This leads me to think we should have forum challenges for things like this. Lots of bright people from diverse disciplines trying to come up with simple, real-world solutions for real-world problems. :)

Like this one:

[youtube]http://www.youtube.com/watch?v=SBWi3NtND68[/youtube]
Made of Stars, by Neil deGrasse Tyson and zenpencils

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Re: How to Accelerate Evaporation Question

#16  Postby shortypowers » Jun 28, 2012 10:13 am

Id like to spark up this post again if anyone is interested..
i've been working up a theory of using different layers of materials with different rates of expansion seperated by a vacuum..
if anyone is interested in collaborating let me know.. this idea of evaporation is something i haven't thought of yet introducing so maybe combining the 2 ideas could prove useful??
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Re: How to Accelerate Evaporation Question

#17  Postby Microfarad » Jun 28, 2012 3:11 pm

campermon wrote:You could use alcohol instead of water.

;)

Or diethyl ether. :grin:
Warning: the content of the post above may content inaccuracies, nonsense or insults to human intelligence. Read at your own risk.
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Re: How to Accelerate Evaporation Question

#18  Postby genie2012 » Jul 24, 2012 2:15 pm

jmdraft wrote:Thanks,

The alcohol could get expensive which would defeat the no bills purpose but its worth messing with on a small scale.


i was reading this thread and got interested its a great idea, so what did happen afterward was the project a success ? did you find another solution for a quick evaporation?
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