A thermosyphon system is a cost-effective way to heat water with solar energy. It makes use of the natural thermal convection of liquids to transfer the heat from the solar collectors to the water tank.
The system is comprised of flat plate collector connected to a water tank with a cylinder-type heat exchanger. The circulation of the heat carrier liquid is driven by natural thermal convection. The heat carrier inside the absorber of the collector heats up by the solar energy and moves up along the piping to reach the water tank, positioned above the collector. There it passes through the heat exchanger and gives away its heat to the water inside the tank. As it cools down, the heat carrier then is returned to the collector to repeat the process.