Hugh,
My wife and I have been looking at ranch style houses right now, mostly to see the floor plans and what works and doesn’t. We came across one where the previous owner got an old slide top bar cooler. He removed the cooling system and put a system of copper tubing inside of it and then connected it to the water inlet to his home. Whenever a water spigot, shower, dishwasher were used in the house the water first flowed through the pipes in the old cooler. He used it to store his vegetables that he grew in the greenhouse. Here, in Alaska, most water from the tap is around 47 degrees or cooler. You could do this to an upright or chest freezer. – oldalaskan