The Story in pictures
Solar is Beautiful.
Some of the nuts and bolts - it all happens with heat exchangers - a way that two fluids can exchange heat, without intermixing.
The coils are created on site, like trying to rewind a slinky, hold it in place and solder it to the uprights. Piece of cake.
The assembled heat exchangers are placed inside the tank. In this case, the tank simply holds water - which doesn't move, or do anything but store heat. While this water has not been changed, it is heated to 180F fairly often.
Note the lower coils, one for each row of panels. Heat, from the solar array, is delivered low in the tank via the low copper coils. As the water warms, it rises, and colder water sinks, so the heat exchanger is always deliver heat to the coolest water, for the largest differential in temperatures, and the most efficiency. Conversely, the taller coils pull heat off the top of the tank, cooling the water so it falls to the bottom of the tank. One of the tall coils is for hot water; the other is for heating the house (in this case, through radiant floors)
With the lid support, and 4 heat exchangers (8 pipes) - its gets busy at the sidewall
This is more complete than it looks - only lacking the tubes in the backrow.
We were concerned about heat loss from the panels back to the tank under the house. Our solution was to build an insulated, waterproof, buried box in which place the supply and return pipes.