This system, as shown is impractical and has many flaws, from both a plumbing and a solar point of view. 1) using the passive solar thermosyphon system as a preheater to an existing system is tolerable but not best practice. If used as shown there is a real risk of thermal flow from the basement heater, despite the flawed explanation about a bleed hole, which will not work in a pressurised system. 2) The header/ filter tank is completely unnescessary and should be eliminated 3) The link between the solar system would possibly work if the hot water from the solar system fed teh cold side of the boiler/ basement water heater and was not connected as shown. 4) The hot from the basement heater must only enter the household hot water flow and must not be interconnected to the solar setup, for the reasons explained in 1. 5) The explanation that a computer would be needed to run the system highlights the impractiblity of this system. If properly designed - as explained - this system needs no valves or interconnections. 6) The entire system should be pressurised - each component should be rated and the system controlled by a pressure reducing valve between mains and the system, as is normal household practice.
It appears that the designer of this system, while well intentioned, has no realworld experience of this sort of system and this is an entirely theoretical system. I would give this system a 2 out of ten if I marked it. Those marks would be for getting the passive solar thermosyphon correct. Nothing else is correct. I suggest this diagram should be withdrawn from its associated articles as it is confusing and inaccurate.
