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Anyone how knows how I can make a mini refrigerator? Answered

Anyone how knows how I can make a mini refrigerator? It has to keep two cans of coke cold. It's for a school project and can't be to expensive, max. 40$. I have acess to special tools if needed. About my english, I know it's bad ;) Thanks for all answers!



9 years ago

You need something called a Peltier element. It's a nifty material that, when current is applied, gets hot on one side and cold on the other. You can tear one out of a portable 12V cooler, or you can buy new ones at www.digikey.com.

or you could use a portable 12v cooler to cool your soda....

Well that's no fun. It's completely logical, but no fun.

best to take the peltier, and the fan + heatsink re-assemble them underneath the mini fridge being designed

Wrong, since heat rises and cold falls, it would make sense to situate the peltier, cold side down, at the top of whatever you are cooling. That way the rising heat from the hot side doesn't heat up the container.

Unless it's being used for pop cans - then it would cool the cans via conduction, which is much more efficient.

Cooling via conduction works the same way: heat rises and cold falls. I reckon the best place for the peltier is on top because as well as conduction (if you make it so the can is touching the peltier) you are maximising the convection effect in the cooler.

That's true I suppose, though cooling through the top of the can probably isn't the best idea due to limited surface area. Hmmm, maybe if the cans were tipped on their sides, with the Peltier placed on top...

What would be pretty awesome is a cylindrical peltier...just slide your can in and probably freeze it :|

or you can make a lead casting the size of the 'dome' at the bottom of the can

Exactly! Or make a whole new fridge enclosure...

I recently considered making a small portable refrigerator with a large Peltier heat pump, CPU fan/heatsink assembly, and some kind of insulated metal vessel. It could be done for under $25 if you find good deals on Ebay. While it sounded impressive at first, I abandoned the idea after estimating how fast it would eat batteries.

Zoophar's evaporative cooling idea is cheaper and more durable. You might consider using something besides sand and clay for water storage if this needs to have a good effectiveness/weight ratio. Perhaps you could create a thick, double-walled cloth tube with an inner diameter that fits one can. Sew a few cents worth of polyacrylate powder ($1.31/oz including shipping if you buy a pound) into the lining of the tube. Slide the two cans into the tube and soak in a bucket of water the night before your trip.

What is the internal size of your prospective refrigerator?

The inside of the fridge will be max. 20*15cm. Thanks for fast answers!