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Making a mini fridge. How many peltier units do i need? Answered

I want to make a mini fridge rather than spend the $80-100 for one. I wanna make it 3'x2'x2'. How many peltier units would i need and do i need heatsinks for both sides (hot and cold)? Also do i need a converter to change the 120v down to something the peltier units can handle?

3 Replies

gmxx (author)2010-06-30

Peltiers will be terribly inefficient for that setup. There is a reason that they arent used commercially like that. If you were going to go this route, you will need to consult the datasheet. I would put a thin metal sheet against the walls, but thats me. You will need to find a converter if you are running them in parallel.

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lemonie (author)2010-06-29

Peltier units aren't that good, but eack should have a data-sheet telling you how much heat they can move?


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lofty (author)lemonie2010-06-30

It depends on the power rating of the device. If you get a higher power one, you may only need one but if you use lower power ones you might need a few.

Insulation is important too, lots of Styrofoam or something similar to keep the heat out. That will reduce the power needed as you can turn the peltier off when it reaches a certain temperature and it should stay cool for a while if you insulate it properly. You'd want to make some electronics to control it all automatically, a schmitt trigger spings to mind.

Use heat sinks on both sides and put a large slow speed fan on the warm side.

You'd need to use a transformer or some other type of power supply to step the voltage down to the right voltage.
Most run off 12v so an old PC PSU should work but some run off 24v too.

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