I have always wanted to plumb in a homemade refrigerator into my incoming water line. Every time you run water in the house, it cycles through the line keeping things cold. The ideas I read years ago incorporated a small steel drum inside a large steel drum with sawdust or sand as an insulation layer between. This idea is simpler with minimal expense.
I'm thinking about trying to plumb this ^^^ into a small spring in my woods, just for fun.
I'm thinking about trying to plumb this ^^^ into a small spring in my woods, just for fun.