... water heaterSG-S serials is Thermosyphon solar water heater, That is a kind of solar water ... solution to get heat power from the sun.Model NameSG-S solar water heaterInner tank ... performance, economy.4) Temperature when exposed to sun without water: 250°C, 2.5 hours to ... °C per day7) Optional accessories: assistant tank, electric heater, reflector ,automatic inlet water valve, Magnesium anode, ect ...