Here is Rick installing my one panel solar water heating system 2 years ago. The small panel on the left produces the power to drive the system.
Glycol is the exchange medium that is pumped from the panel on the roof to the heat exchanger in my basement.
The small cube on the right is the heat exchanger. Heated Glycol comes down from the roof in insulated pipes and heats via an exchange water from our well that is then stored in the water heater on the right. The main water heater draws on this hot/warm source. On a good summer day the water is so hot from the solar heater that no extra power is required. On a modest day it means that the water heater draws warm water rather than cold water fromt he well.
When we first put this in – we and the ‘guys’ knew much less. We connected the solar source directly to our oil furnace. But the furnace would constantly be heating its own water jacket without drawing on the solar heated source.
Now the new norm is to isolate the furnace completely.
When you do this be careful about how the systems connect so that you maximize the value of the solar heat.
Oh and my economics? I used to use an entire tank of oil from May to September. About $1,000 now. My investment in a one panel system is just over $4,000. I am expecting an ROI of somewhere between 12% – 20% depending on the weather for there will be some electrical costs.