My parents have always had an "outdoor fridge" that is a stainless steel equipment box that my dad salvaged from the junk pile at work. They put food in there that is less prone to spoiling, and use it through the fall/winter/spring months.
If I make a big pot of soup in the winter I will cool it down outside before putting it in the fridge. That way it gets down below the zone where bacteria grow much faster than if it were inside.
From an energy perspective it would be better to put it in the fridge so the heat would be removed by the fridge and stay in the house rather than dissipated outside but as far as I know the heat would also end up in the other goods in the fridge causing potential spoilage. It would be nice to have some kind of remote chiller pot hooked to a heat pump that would just pump the heat out of the soup and into a cold room.
The fastest way to cool it is to put the pan in a sink with cold water. But since that water is probably freshly tapped and thus cold, you're not really regaining heat, but rather warming the outside (if you then flush it).
But I find fridges are pretty good at what they do. If it fits, you can put it in the freezer for half an hour first.
