Compact solar water heater ---non pressured system 2)Vacuum tube: 47mm-1500mm. 58mm-1800mm spaceflight vacuum heat collecting tube large amount of heat gaining. 3)Inner tank: Imported SUS304-2B food-level stainless steel. Thickness is 0.4mm or 0.5mm. 4)Outer tank imported colour steel ( imported stainless steel imported zinc aluminum steel plate ). 5)Bracket: Elaborated designing, high intensity plating aluminum and zinc steel board, treated by dry painting, stainless steel, aluminum alloy. 6)Technique characteristics: Use automatic argon arc welding technique. Good pressurization capability. Super antisepsis capability in welding joint. No seeping forever. Use automatic machinery foaming technique, super insulation capability.