A research team at Stanford has developed a refrigeration device the size of a thermos. What’s interesting is that it uses no electricity. Zip. Zero. Nada. Zilch. Instead, it contains some kind of coolant that becomes cold when it’s exposed to heat.
Details are scarce, but the units would be fairly cheap to produce at about $50. The price makes it an ideal way to deliver medicines and cold water to developing countries as well as having a bunch of other uses a bit more noble then your next camping trip. It’s a great breakthrough. All a user would need to cool any given thing is fire, which is readily available.