I've seen versions of this in Asia. They used a porous pot into which they put the container of stuff they wanted to cool. As the water evaporated, it cooled th

I've seen versions of this in Asia. They used a porous pot into which they put the container of stuff they wanted to cool. As the water evaporated, it cooled the water, which cooled the container, which cooled the contents. I still remember drinking what felt like an icy drink compared to the ridiculously high temperatures outside. Happy days...