OK, he’s not exactly a retired rocket scientist; he’s a retired airplane product development engineer - but Gary Reysa has built his own homemade very simple-tech solar hotwater system that is the functional and thermal equivalent of commercial systems costing 6 or 7 times as much! This simple design has survived Montana winters with temperatures down to minus 30F with not even a hint of a problem, while providing an unusually high solar fraction of 94% (75% is typical of commercial solar hot water systems.) For details and a picture of his solar thermal shed hit the fold: Read more of this story »