could cave man make a fridge?

could cave man make a fridge?

yes..

using bamboo..
and a wind vortex cooler

vortex tube or Ranque-Hilsch vortex tube

instead of using air.. water is used to power it.. this will solve the pressure need as rivers are abundant.. and water has a better heat capacity and thermal conductivity.. even so it will only drop temps of the water by about 25°C wich is better then an optimal 15c for wind.. combine this with evaporative cooling .. a deep pit with a clay pot that evaporates water to wind currents and you can get your food to almost frozen overnight

tally...

clay pot
bamboo
river
master crafting in wood working
master crafting in clay pot making

estimated cooling -20-30C

the water wicks up the pot so the inner water level is low.. a glazed in ash inner pot can keep food dry
if you use a fire to draw air past the evaporator cooler you could maybe get near freezing

Not an expert, but Wikipedia mentions this is using gases, so I am pretty sure it does not work the same for liquids.

And for gases it needs compressed gas (I have seen with a quick search that it needs at least 2 bar), so I do not think cave man could make a system that withstands that (but I did not check either!)

In the 14th century, the Incas of the Andes in South America were freeze-drying their potatoes for long term shelf stable food. Many cultures independently also used different evaporative methods of food preservation similar to modern freeze drying, until early 20th century American patents found an industrial method.

I believe areas of China used heavily chilled salt water to freeze pure water and transport it for the affluent.