snwbrdr

ok i tried this again after some sleep, I used a different method, instead of using a equation I used this chart

and fromt that chart it says at 80% i will have 24.3 grams per meter cubed. and that is approx 1 ounce of water, so my cab using this chart has 1.6 ounces of water per cubic meter.......


so anyone want to help me with my math? 26 is alot different than 2, but i tend to believe that chart over my math when i had no sleep.

If i only have 2 ounces in the air then a small peltier dehumidifier would work great cuz they remove about 4-8 ounces of water in 24 hours......if its 26 then a larger unit would work better but would be over kill, cuz it jumps from like 8 ounces to 25 pints........

hmm more searching i need to verify my calculations some how, dang now im starting to wish i payed more attention in physics

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analog

Air temperature in degrees C Water vapor air can hold at this temperature.
30 degrees 30 grams per cubic meter of air
20 degrees 17 grams per cubic meter of air
10 degrees 9 grams per cubic meter of air

Followed some earlier link that you posted. I fixated on this chart... to attempt to help answer..

At 30 degrees, 100% relative humidity would be 30 grams of water vapor per cubic meter.

Seems to me like a small peltier would work fine if its rated for 4 - 8 ounces of water vapor per day.

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GreenDragon2k

heres soemthing else to confuse you more... when your humidity goes down, the evaporation (from the surface of the water in your system) and the transpiration from the plants leaves will also go up so your actually dealing with a lot more water than whats currently in the air

sorry just had to throw that out there

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snwbrdr

analog thanks

greendragon - I had a very strong suspicion that something like that would happen. makes sense, if im at pretty much max humidity then no more water can evaporate until some is removed.

so I would say i would need a dehumidifier that can remove 2-4 times of the max amount of water in the air, IE if the air right before saturation is at 1 ounce then i would want something thats removes 2-4 ounces, id prolly go for 4x to be on the safe side

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Don_Hydro

Whirlpool $148.00US works great up to 1500 Normal sq. ft. so for us half that.

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analog

Another example seemingly off topic but not really is the Chicago Marathon this last weekend that sent loads of people to the hospital.

Air circulation will help mightily as will surface area.

Is that special crystal Kitty Litter a possible help with yanking water out of the air for you?

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snwbrdr

I have lots of circulation inside the cab

any sort of disposable desiccant or water absorber will probably be a waste in the long run however would work to some extent im sure.



I went ahead and bought a small peltier model and should receive that in the next few days. if it works better than my model i will not bother to redo it, if it doesnt perform very well ill consider rebuilding mine to see if i can improve efficiency. I realized today the parts for my dehumid cost me well over 50$ originally(i had them all laying around before the project) so if this store bought one for 40$ works better then my model is pretty much a fun gadget to build but not very cost effective.

soon as i get more info ill post it.

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Underarock

I use a $85 Samsung window unit

in a 100 sq by 8 ft tall (800 cubic)

I have to use a humidifier to keep the humidity up in the room

nominal outside the room is 90f x 75%rh
inside is kept at 75f x 50% w/ 600ppm co2
(the co2 is not used as an advanced growing method, I don't run that much light, it's so they don't deplete the air in their sealed room)

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snwbrdr

is that just a AC unit?

yeah my temps out side the cab are 70f and 40% humididty, if the temps were warmer my AC unit would run 24/7 and do the trick for me. but the AC unit only kicks on every now and then.

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Underarock

actually to remove the humidity, you want the unit to kick on pretty cold but for a short period of time

you want the evaporator coil to become colder than the dew point in the room, but still for a small application, you would want one without digital controlls and use a heavy duty timer ($20) to cut the unit on for ..say an hour a day)

remember: digital controls will always reset to off when used with a timer, old fashion on-off swithes will stay in the on position regardless if you kill the power to them

In my application, I'm trying to reduce the heat, not the humidity, but I have about 800watts burning, so the a/c runs about 16% of the day (at 600 watts [.16 x 60= 10 min/hr x 24 hrs = 4 hrs/day x 600w/hr =24,000 watts/day= 24kw/day x .15/kw = 3.60/day or $100 a month]

regardless of the cost.......a dehumidifier is an ac unit....it just recombines the warm air and the cold air back together after removing the moisture from the cold coil

it really depends on what you want to do with the warm air as to which machine will work the best
my window unit....the part that normally faces the inside of a house, faces the inside of my room
the part that normally hangs out side the window is in a box, so it pumps air out of my garage, heats it a little, and vents it into the attic
in the winter, it heats attic air and pumps it into the garage

those small peltier coolers rate out at a 40 degree drop on one plate, really would be hard to make one sweat

the best chemical dehumidifyer is a pool salt
calcium chloride (sold as water hardner for pools)
when left in an open container will continue to draw moisture for years
(like 2 oz of salt will be 8oz of salt water in a few days)

this is the same salt they pellet your yankee roads with in the winter
when sprayed onto a dirt road, it keeps the dust down, because it keeps the roadbed 'moist' all the time

good luck

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