There are two types of passive solar heating; a
storage tank that collects heat directly from the sun or a heater which uses
convection, known as a
to heat the water tank.
The thermosiphon uses a solar water heater panel
to collect heat from the sun and move water against gravity into an insulated
You can see how this works in the video above
where a splash of red dye shows how the water circulates though
the storage tank.