Water Maker

Discussion in 'All Things Boats & Boating' started by Fanie, Jan 3, 2015.

  1. Fanie
    Joined: Oct 2007
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    I'm currently playing around with making water from air... which had me thinking that this could work exceptionally well on the water.

    If one uses a peltier cooler with just the right amount of heatsink for cooling the heated side, and a filter (lol for if you're on a dusty stretch of water), fan and a smooth surface area metal shaped for dripping the condensation into a container, you may well have a relative long life water maker.

    Condensation happens when air meets a surface that is a certain temperature colder than the air temperature. This cold contact to the material increases the relative humidity level to 100% and dew form on the cold surface, enough makes drops that runs down into a reservoir and you have water.

    It may not be enough to take a bath in, but I'm sure it may be good for drinking. It should also be cheap to run and may not even require any maintenance other than drinking the water so it doesn't overflow ;)

    You can look on youtube how the peltiers work. The humidity on water should always be relative high so one may well be able to condense enough drinking water without having to put up with a large unit. It can be run off a solar panel or other suitable power source.
     
  2. Rurudyne
    Joined: Mar 2014
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    Rurudyne Senior Member

    Now if only you could make Whisky from air...

    (Serious: sounds like a neat idea.)
     
  3. Poida
    Joined: Apr 2006
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    Poida Senior Member

    Should work fairly good when it's raining :rolleyes:

    Poida
     
  4. Fanie
    Joined: Oct 2007
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    Fanie Fanie

    LOL, my wife said the same thing, however, if you go on youtube and search for "water from air" you will find they are actually doing it already. You guys are using them as de-humidifiers in your houses, then throw the water out.
    On boats you want to throw the water in :confused:
     
  5. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow I'm not a cat.

    Making fresh water from any salt, brackish or swamp water would be easier.
     

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  6. Fanie
    Joined: Oct 2007
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    Now you need a heat source which is a lot of energy for relative little water.

    Nice drawing :D Btw, it's called a liebich cooler, learned it in grade 1.
     
  7. hoytedow
    Joined: Sep 2009
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    hoytedow I'm not a cat.

    You are too generous. If the pot is black and the spiral tubing is white with a bit of cold dirty water running over it the sun could provide enough heat.
     
  8. pdwiley
    Joined: Jun 2008
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    pdwiley Senior Member

    No question it works, big question how well it works.

    Hook up a peltier block assembly to a fully charged 100A deep cycle battery. Measure water volume produced by the time the battery voltage drops to say 11V. Let us know the answer.

    Even that's going to be dependent on ambient air temp and relative humidity.

    Personally I very much doubt the efficiency is there; I know Peltier blocks make for power hungry & inefficient refrigeration. However I'm always happy when some quirk of technology shows I'm wrong..... especially given the price of RO watermakers.

    PDW
     

  9. Fanie
    Joined: Oct 2007
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    Hello PDW,

    What I have in mind (for myself) is a small unit I can carry around, so it must be lighter in weight than taking water, can work off a small solar panel since a peltier works with current rather than voltage like a LED. I am aiming at around one amp current, there are units rated at lower voltage/watts than the ones used for freezing.

    Like solar panels peltiers are unfortunately inefficient, the advantage is no moving parts. To double the efficiency one can use two or more in series of the low voltage ones and by carefully determine the plate sizes. You only want a relative temperature difference that will take the water vapor to dew point, not freeze it by running the peltier at max current.

    The times I played with peltiers I can remember it was always a problem keeping the cold side dry, and if it was left for a bit a small puddle would form that you have to dry often. If you have a small trickle from a larger surface, one can make a couple of liters per day.

    One would probably use two small fans, one to keep the heated side as close to ambient as possible, the other force air on the cold side plate. There should be a balance between the air flow rate, the cold plate size and the current required to maintain the relative temperature difference. It may even be possible to use one fan, a certain volume of it's capacity flows over the cold side while the rest cools the hot side. The cooled air that flowed over the cold side can then assist in further cooling the hot side. Too much air flow over the cold side may well evaporate some of the water again.

    Also, if you pressurize the inflow air you reach the dew point quicker. That means you will have a chamber under pressure with a pressure release. No idea how well this will work.

    The water should be slightly cooler than ambient though, and IF one can pressurize the thing you can pump it as well. I have a miniature pump, although I doubt the volume is enough.

    Wish I had a 3D printer....
     
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