For the non-pressurized thermo-siphon system, its storage tank and evacuated tube collector are installed as one unite on building roof. Run by natural circulation, the system can work without electricity. The hot water flow rate of this kind of system mainly depends on height difference between the water tank and the hot water shower head. Filled with cold water in the morning, the water can be heated during the day. The heating capacity is mainly depending on solar radiation, number of tubes, etc. Dimension: Technical Data Thermo siphon System Evacuated Tubes Outer Diameter 47mm/58mm Storage Tank Inner Material Stainless Steel SUS304-2B Storage Tank Outer Material Painted Steel/ Stainless steel SUS304-BA/ Zink Aluminum Galvanized Storage Tank Capacity 100L/ 120L/ 145L/ 180L/ 230L etc.. Storage Tank Insulation Polyurethane HFC-245FA Reflector CPC/ Aluminum Reflector/ Without Reflector Aluminum Bracket Inclination 42/30 degrees/ pitched roof installation