So I have 2 30 gallon barrels in my greenhouse for thermal mass storage. Soon it will be more consistently getting into the single digits so I need to have the water to be warmer going into the evening.
I am building a solar heat collector using 3/4 copper and a salvaged window and plumbing the barrels together. The goal will be hot water from the sun using 60 watts from the pump while the sun is out and radiating it into the greenhouse during the cold hours of the morning.
So far this is what I have for plumbing the barrels together.