Back in the day when I first had thoughts of building a house, solar was on my mind. In Washington, winter is when you need the solar, Colorado would have been good, the gray sky just don't work for you.
So I built my first circle,using 200 ft of tubing, and another 1000 ft on the hill (see the background) we managed to get a four degree surface temperature rise today.
""The world is full of obvious things which nobody by any chance ever observes…""
— Arthur Conan Doyle
“The Hound of the Baskervilles”
""Mathematics...
However, we are getting a 30F gain in water temperature with this arrangement.