... worksThe design of this type uses the all-glass evacuated solar collector tubes as the heat absorb element. The high vacuum ... assure the vacuum tubes to use long time. Non-pressurized Solar Water Heater TECHNICAL DATAWATER STORAGE TANKSMaterial of out tankHigh quality ... alloyBracket angle:0,18,22,38,45 optional, pitched roof, flat roof optional.Fastening pieces:Made of zinc-coated stainless steel ...