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Thread: Peltier cell questions

  1. #9

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    I guess the thing that I need to clarify is that it wold be at least 30 layers of aluminum foil, the first few attatched by that thermal what ever stuff... Thanks again, I plan onsetting this soon, I'll keep you updated!! [img]http://www.**********.com/iB_html/non-cgi/emoticons/biggrin.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/smile.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/alien.gif[/img]
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  2. #10
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    30 layers of aluminum foil won't help. You will basically be insulating the peltier with air space between the layers.

    You need a cpu style heat sink that is carved out of a solid block of aluminum. One goes on the hot side and one goes on the cold side. Something like this cpu heat sink
    The trick will be getting the peltier sandwiched between them.
    This page shows thermal grease which might be all you need if you can physically machine screw the two sinks together with the peltier between them. Or perhaps the silver epoxy to glue each sink to each side of the peltier thermal compounds
    Is that a Nepenthes in your pocket or you just happy to see me?

  3. #11

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    This is right up my alley, I have used pelts many times to cool my cpu.

    First of all, a 250w PSU would be streatched pretty thin to run 2 pelts and 4 fans. I would definatly get at least a 350w.

    Second of all, the more heat you remove from the hot side, the cooler the other side gets, so depending on your price range, I would get a quality heatsink/fan combo. (Thermalright SK800 is probably the best on the market, but can run 30-40 bucks) couple that with a nice 80mm fan, OR you can get an adapter and put a 120mm fan on it (larger area, so the fan spins slower and moves more air READ: it is much quiter)

    Now, if this was my project, I would put a waterblock and a cheap pump on the cold side. The TEC would cool the water, then run it through some copper tubing (kind of like a radiator) and put a large 120mm fan on it. This will in effect, give you a MUCH larger cooling surface in which to remove the cool air from, ortherwise you can simply put another HSF on the cool side, but you will not be using it to its full potential.

    If you decide to do this, shoot me a message and I can help you with a whichever setup you decide to go with.

    Also, if you get an AT Powersupply, you will have to mod it to make it work. ( they are designed to turn off and on by a computer, hence they won't work unless the ATX cable is connected to a motherboard, this is easily fixed by jumping two of the wires on the ATX leg)


    Casper

    PS: As far as the HSF, you really want to stick with copper, instead of aluminum, the heat transfer is much better with copper, and for thermal compound use Artic Silver 3, one 6 dollar tube should last you forever.

  4. #12

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    I wish that I had a better way to describe this... I could also melt down the aluminum if that would be better... I want this to be as simple, effective and cheap as possible, and since I soon plan on expanding to a bigger tank, I want to get it right in here first. Thanks again, I am still working on it... [img]http://www.**********.com/iB_html/non-cgi/emoticons/biggrin.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/smile.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/alien.gif[/img]

    EDIT:
    Quote
    Now, if this was my project, I would put a waterblock and a cheap pump on the cold side. The TEC would cool the water, then run it through some copper tubing (kind of like a radiator) and put a large 120mm fan on it. This will in effect, give you a MUCH larger cooling surface in which to remove the cool air from, ortherwise you can simply put another HSF on the cool side, but you will not be using it to its full potential[/QUOTE]

    I can't find anything about waterblocks, are they cheaper/more expensive, and do they work better/worse? THANKS again!! [img]http://www.**********.com/iB_html/non-cgi/emoticons/biggrin.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/smile.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/alien.gif[/img]
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  5. #13

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    Ok, I am going to slightly change these questions to accomidate a well welcomed 50 Gallon Long!! [img]http://www.**********.com/iB_html/non-cgi/emoticons/smile.gif[/img] Anyways, the tank itself is: 50 Gal. Long 48L x 18W x 13Tall It is made of Acrylic, and when fully setup, will have 2 48" Florescent tubes on top, and a Tropic Aire with a 55 Gallon pump for humidity, you will see why it's neccessary in a sec.

    Anyways, I was wondering if I would need 2 or 3 peltier cells/heatsinks? I would like a drop from about 72-75*F down to 55-48*F

    Here is how my setup would work:
    Click here




    FIGURE 1:

    Yes, the tank is sealed, that's why I said the Tropic Aire is important... That way the fan can't make the air dry out...

    Figure 2:

    I am trying to see if I can get around cutting up the lid of my Growchamber, by integrating the lid into the peltier to coldsink connection... If you have any opinions, I could go into more detail... THANKS!! [img]http://www.**********.com/iB_html/non-cgi/emoticons/biggrin.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/smile.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/alien.gif[/img]
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  6. #14

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    Just a further suggestion:

    Place all peltier cells/heatsinks together at one end of the tank (but not too close to the end wall) using one set of fan to blow at the cells to create a cool air circulation in the tank. Place another fan set on top of the lid to cool the heatsinks.

  7. #15

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    Ok, thanks!! That's one nice suggestion! How about the question about figure 2? Thank you for all of the input!! [img]http://www.**********.com/iB_html/non-cgi/emoticons/biggrin.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/smile.gif[/img] [img]http://www.**********.com/iB_html/non-cgi/emoticons/alien.gif[/img]
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  8. #16

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    I must disagree, you want to place a fan directly on the pelt. blowing air down.

    You see, pelts work on heat transfer. The more energy transfer, the colder it gets. So.. in easy terms, the more heat you pull off the top, and the more cold you pull off the bottom, the cooler it gets. Having a fan blowing accross it from a distance will yield cool temps, but having a 5 dollar heatsink/fan combo actually attached to the pelt will yield much better results. Now, if you wanted to blow the air sideways like in your diagram, you could probably use a pvc elbow to change the direction of the airflow for next to nothing.


    Casper

    P.S. You better have a serious power supply to run 3 pelts and the fans, and you DEFINATLY want to make sure its grounded (don't cut off the ground to fit it in a cheap timer)

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