Evaporative coolers: A new implementation of an old idea

It uses evaporation of water to keep food cool.  An old technology which is being rediscovered.  Reminds me a bit of swamp coolers.  Believe me, these swamp coolers can work.

Update:

If I understand these things properly, then it may be possible to use them for cooling down a larger area, too.  You see my meaning?  I had an idea to make a "coffin", in which energy use would be kept to a minimum.  The idea is to ring the "coffin" with a layer of sand, and then have this sand filter gray water, and as a bonus, it would cool everything inside the coffin, including me!  Of course, I don't mean a real coffin.  Just a small space that could allow one to lie down when it is hot, and thus cool off.