... Working Principle Of Solar Water Heater Turkey: This system uses the thermosiphon principle, Solar vacuum tube is ... principle, the hot water rise up, and arrive in the water tank, the cold water inside the ... go down the solar vacuum tube, so the system runs by this circulation way until the water ... 4. Water tank heat insulation layer: 50~60 mm polyurethane foam.5. Stand angle: 15 degree, 20 degree, 25 ...