Thermosyphon solar water heater relies on the natural circulation of water between the collector and the tank or heat exchanger. In this type of installation, the tank must be located above the collector. As water in the vacuum tubes is heated it becomes lighter and naturally rises into the tank, Meanwhile, cooler water in the tank flows down to the bottom of the vacuum tubes, causing circulation throughout the system. These systems move household water or a heat-transfer fluid through the system without pumps. This kind of passive systems have the advantage that electricity outage and electric pump breakdown are not issues. This makes passive systems generally more reliable, easier to maintain, and often inexpensive. Features: * Inner tank: Stainless steel(SUS304 2B) Thickness: 0.5mm Cr:17.00~19.00 % Ni: 8.00~10.00 % * Outer tank: Stainless steel (SUS304 2B) Thickness: 0.6mm * Insulating layer: Foaming polyurethane Thickness:55mm Thermal transfer rate:0.022W/m.K * Sealing rubber: silicon rubber * Dustproof rubber: EPDM * Optional Auxiliary Electric Booster: 1500w *Optional Controller and automatic filling valve or assistant tank * Highly efficient all glass vacuum tube *Cheap but reliable solution, Simple structure, Easy installation *Operation without any power supply could be *Could be installed using parallel and/or series connections *hot water can be used directly for, or can be used as a pre-heat