... tube could transfer hot energy to cold water in pressurized solar water heater tank rapidly4.The whole pressure of the system is up ... from tap water and hot water,when use, the hot water comes out because of water pressure.2.Vacuum tube absorbs solar energy, and conductive ... 5mm thickness Galvanized SteelStructure of tank:5 holes for air vent,water inlet and outlet,electric heater,Mag ROdWelding:Argon ...