solar heat collector with SOLAR KEYMARK,CE,ISO,SGS Solar heat collectorMaterial:Header tube: seamless copper TU1, 22×δ1.2mmFlowing ... alloy, δ1.6mmInsulation: polyurethane frothing, δ40-50mmVacuum tube: tri-elements coating, copper heat pipe inside, 58×1800mmCopper ... .8mmBracket: 1.6mmHeat insulation layer: 50mmPrinciple:Solar thermal collector (by vacuum tube with copper heat pipe inside or flat ...