Power Supply for a Portable Temperature Regulator

Discussion in 'Power Electronics' started by Maria ella, Jan 7, 2018.

  1. Maria ella

    Thread Starter New Member

    Jan 7, 2018
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    Hello. I'm doing a project about portable cooling and heating regulator I'll put it in the sleeping bag for camping then I would have used TEC.

    Questions:
    1. Is it enough for a TEC to reach its cooling <15 ° C and heating> 30 ° C

    2. How much time will it take since dc power supply it?
     
  2. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Q3, What is a TEC?
     
  3. #12

    Expert

    Nov 30, 2010
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    thermo-electric something
    Those DC heat exchangers.
     
  4. dendad

    Well-Known Member

    Feb 20, 2016
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    I dont think a Peltier device will work as you expect.
    They are fairly low thermal power devices for a significant current input. Also, you need to isolate the hot and cold side. They are acting as a heat pump, so the heat is taken from one side and moved to the other side where it must be removed. Just sticking it in a sleeping bag will make the lot just get hotter until it dies.
     
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  5. Maria ella

    Thread Starter New Member

    Jan 7, 2018
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    If so, what is better to use in sleeping bags for camping and mountain hiking that it will leave the air cool and hot depend on the user's input as it will be a and low cost portable device
     
  6. recklessrog

    Well-Known Member

    May 23, 2013
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    A better sleeping bag?
     
  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    It would be difficult to get a uniform distribution of temperature with any portable device inserted in a sleeping bag. I think you'd end up with an uncomfortable hot or cold spot. You could design a sleeping bag with a built-in zig-zagged heating element, but doing something similar with a cooling arrangement would be a challenge.
    A sleeping bag with removable layers of thermal insulation seems a better option.
     
  8. Maria ella

    Thread Starter New Member

    Jan 7, 2018
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    f so, what if I use blower fan for cooling and old heating pad for heating? Is that ok for dc source?
     
  9. dendad

    Well-Known Member

    Feb 20, 2016
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    An external heater/cooler of some with a fan blowing the air in may work but I think a basic problem will be the power supply. To power such a device for any time and at usable levels will mean lugging quite a weight of battery pack around I would think.

    12V "computer" fans would probable work ok, nor domestic AC driven ones.

    And "an old heating pad" could be anything. Can you post details of the heating pad so an opinion can be expressed?

    Have a look at the heating pad and see what the power rating is. The estimate how long you would want it to heat for.
    That will give you an indication of the battery size required to run it.
     
  10. wayneh

    Expert

    Sep 9, 2010
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    Thermoelectric cooler. TEC is the common term in the industry and you won't find them called Peltier coolers except here and in physics forums.
     
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  11. wayneh

    Expert

    Sep 9, 2010
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    Is this homework, or are you constrained to using particular solutions?

    If not, the best way to add warmth to a sleeping bag (other than throwing a blanket on top) is chemical energy. Crack open a hand warmer or two and that's it. The disposable ones are very inexpensive. The fancier ones use crystallization of a superheated solution in a plastic bag-like package and can be re-used by remelting the crystals. I think you put the bag in boiling water to recharge it. I can never remember the salt inside but it's something simple like magnesium sulfate (that's epsom salt and that's not it).

    Cooling a sleeping bag is a much more challenging problem. I'd look first to two options depending on where you are. In dry environments, a swamp cooler could significantly cool the inside of a tent. They don't need a lot of power and are pretty simple to rig up. In moist environments they won't work so well and in my limited experience, the problem in those environments is the humidity more than the temperature. You lay on top of your sleeping bag and sweat anyway. A swamp cooler would only make it worse. Dehumidifying a tent would be hard without a ... dehumidifier, which is just an air conditioner. Cooling a sleeping bag in a humid environment could result in condensation if the cooling 'coil' goes below the dew point, and that would NOT add to comfort.

    A TEC is a poor solution because it draws a lot of current from the power supply and turns a lot of it to heat which must be dissipated. That's OK for certain applications (they're popular in wine fridges) but not very useful for most. If you have gobs of power available, I could see turning a tent into a wine cooler. A TEC mounted at the top of a tent, venting the heat up and outside, could send a bit of cool air down over the campers and provide a little relief.

    Have you seen the clothing with integral cooling? Kinda cool. No pun intended. I'd love to never have sweaty nethers again.
     
    Last edited: Jan 9, 2018
  12. #12

    Expert

    Nov 30, 2010
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    I think we've gone over this in another Thread. A dehumidifier is just an air conditioner...with a low rate of air flow.
    So the humidity has an improved rate of turning into liquid water, which can be discarded easily.
    And the Fahrenheit temperature is affected less that a normal air conditioner would affect it for the amount of energy expended.
    But thanks for remembering the basic relationship.;)
     
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