Cooler Doubt

Discussion in 'The Projects Forum' started by nradam123, Dec 11, 2013.

  1. nradam123

    Thread Starter New Member

    Dec 3, 2013
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    I am making a peltier cooler to keep my beer cold while watching TV :) The cooler is open, means the drink will be kept on a tray that is open to surrounding and keeps it chilled

    My design is simple, just a heatsink+fan assembly from computer, a peltier chip and a 12V adapter. The peltier chip is stuck on the heat sink along with some thermal grease to increase thermal conductivity. The peltier chip is connected to the power supply through a 12V adapter (my peltiers rated power is 15.4V).

    I havent assembled the components yet, but i am confused on what to use as the material for tray on which the drink will be kept. Problem is, i wanted my cooler to chill 2-3 glasses and hence i want a large tray. So if i just keep one drink on the tray, a large area of tray will just waste energy since it is not insulated. What material shall i use as the tray on the cold side of peltier so that:
    a) There is minimum heat transfer to surrounding and maximum heat transfer to drink. Means the material must be able to hold heat for a long time. It must have high conductivity, and low convection and radiation rate.

    Also as a side question, most mugs, glasses etc has a bottom where only the circumference will touch the surface. This has a low contact area. How do i make an arrangement so that the contact area is higher for any glass that i keep on the tray?? :/ :eek:

    Thanks for any replies :)
     
  2. wayneh

    Expert

    Sep 9, 2010
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    I really don't think you'll be happy with all this. A few problems:
    1) A peltier is very inefficient. This means as much as 10 units of heat are consumed for every 1 unit moved from the cold to the hot side. So 11 units show up on the hot side for every 1 removed from your beer. You need big heat sinks and fans to remove all that heat.
    2) You can improve the efficiency by operating the peltier far below its peak ratings. For instance if it's rated to 10A, run it at 2A for better efficiency. Trouble is, the ∆T from cold face to hot face is reduced when operating at lower current, and so is the heat moving capacity. This suggests using MORE peltier elements, which is a possibility for you.
    3) A cold plate will have minimal effect on the temp of anything placed on top of it, even if it has a mating surface. Even a block of ice wouldn't work. That said, I envision a nice big slab of aluminum. They make them for thawing steaks. Might be worth a look.
    4) You need to move more heat to the hot side, and blow it away, than flows in from ambient sources. I don't know how many watts we're talking about but without insulation, I think it'll be a lot compared to the capacity of the peltier. And you need to remove heat from the beer to chill it as well. It just adds up.

    Sorry to be the bearer of bad news but you need to know the challenges upfront.
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Just drink the beer faster... Problem solved..
    Works just fine for me anyways..I NEVER have a warm beer. Even when double fisting. ;)
     
  4. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    They make beer mugs that you put in the freezer first to keep your beer cold.
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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  6. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    That engadget post is from 7 years ago. Seems like a waste of resources and space for the beer.
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    yes I know but it did have reference to a peltier device also in there..
    edit..which doesn't link to anything good.. oh well..
     
  8. Metalmann

    Active Member

    Dec 8, 2012
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    That's the way I did it, back when I loved me some cold beer.;):D


    Can't stand the smell nowadays........not really.
     
  9. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Just some random thoughts....

    Make sure to insulate well between the hot heatsink and the cold side.
    Aluminum or copper for the cold plate.
    Either cut the cold plate to match the cans or insulate the top side so only the circles are exposed to air.
    A foam cylinder could run part way up the can to insulate it from the air.
    Inside that you could put some little flaps so that the can would push thru so that an empty slot wouldn't be exposed to the air.
     
  10. strantor

    AAC Fanatic!

    Oct 3, 2010
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    My idea for a beer cooler is a copper tube spiral that is just the size of the bottle, so it touches the bottle on all sides for maximum heat transfer, but doesn't clamp it. The two ends of the tube go through two holes in the top of a cheap thrift store mini fridge/freezer, where they are connected to an automotive heater core, in closed loop, with a small circulating pump. Pump glycol through it. You get a beer cooler, a cooler for beer, and a beer cooler end table/ conversation piece all in one.

    There's probably a more efficient way, like modifying the freezer's own refrigeration system and using directly the refrigerant in the beer cooler coil, but I'm not "one" with reefer systems so I wouldn't try that unless the first idea proved to be crappy.
     
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