There's a possible mechanical substitute. If the metal container can be designed as a giant syringe, sealed off at one end and expanded, the pressure on the air molecules goes down and so does temperature. As the cool air in the container interacts with the warmer air, temperature will slowly go up again and volume will slowly decrease, meaning the syringe will contract (if that's the right word). Start the process again. It takes some work but it can be done without electricity. Here's a really amateur depiction.
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Just throwing stuff out there. I'm saying its possible but the mechanics have to be sorted out.What you're suggesting is same as this:
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You say you only need little energy to expand/pull syringe.
Yes, that's true but you will get 1-5 degrees Celsius difference. Maybe less than that.
You need to expand A LOT more to get significant temperature reduction.
It's hard to calculate how much energy but the fact we need a refrigerator proves that manually expanding a syringe is not enough.
Link?