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How to chemically Accelerate Evaporation?

  1. Apr 5, 2012 #1
  2. jcsd
  3. Apr 5, 2012 #2
  4. Apr 5, 2012 #3
    Why? What do you think increased evaporation would be advantageous?
     
  5. Apr 5, 2012 #4
    I’m not sure what it will do which is why I’m messing with it. Speed up the process maybe……………….

    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.

    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.

    I have to start cooking dinner now, but I’ll check back later.
     
  6. Apr 5, 2012 #5
    The outer container of the 2 pot cooling system should be porous to the movement of water. Unglazed clay would be such a container. An outer vessel of plastic like your Coleman would not work, unless of course you poke multiple holes in the walls and line it with a fabric to contain the filler. The filler material between the two containers would be something that retains water such as sand. If the outer and inner vessels are rigidly supported then pure water with no filler could be used, although in that case the complete inside surface of either container is not wetted and lower effciency would drop as the water level drops.. The inner vessel can be of any material such as metal, plastic or ceramic.

    As the water evaporates from the surface of the outer container, water from the filler material moves to the outer container. So you have to add water at regular intervals to keep the filler moist and not go dry. The evaporation takes heat away from the vessels leaving them cooler. The cooling effect is related to the relative humidity of the air, so in a dry climate it works better than in a humid climate. The maximum cooling temperature obtained is never lower than the dew point, so do not expect to be making ice with only this type of system.

    A fan blowing on the outer container will increase the capacity of the system but you may achieve a few more degrees in cooling and faster cooling at initial startup.

    A system of thes type could augument another type of refrigeration cycle by decreasing the cooling load, such as the Peltier in your Coleman , in which case you could make ice quicker, but you would have to set it up correctly.
     
    Last edited: Apr 5, 2012
  7. Apr 5, 2012 #6
    I appreciate your interest and the time you have taken to provide and explanation but your comments are very strange to me. I don’t remember if I was able to send an attachment in this forum. If not, I would like to send you a word document which explains my project. Your mention of the Coleman cooler seems to imply that you saw the attachment but other than the fan, my project has absolutely nothing in common with the cooler. The fan does not blow on my device but instead pulls warm air out of it (like the cooler). The external walls are not of plastic but are porous and allow water to pass through them. If you have not read the attachment and are still interested, please provide me with an email address so that I can send it.
     
  8. Apr 6, 2012 #7
    No need. If you understand the concept of evaporative cooling you should fine with your project.
     
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