> Air conditioning is probably a top 3-5 all time human invention. No such much AC specifically, but rather the refrigerant loop generally, IMHO. Being able t

> Air conditioning is probably a top 3-5 all time human invention. No such much AC specifically, but rather the refrigerant loop generally, IMHO. Being able to keep humans cool, but also food chilled (to limit bacteria growth), food frozen (for long term storage and transport), as well as medication, vaccines, blood, tissue samples, etc. The cold chain (in logistics) is a marvel of human accomplishment: * https://en.wikipedia.org/wiki/Cold_chain https://en.wikipedia.org/wiki/Cold_chain