... ,Extremely strong transparent glass. stainless steel solar water heater systemSpecifications: 1) Outer shell of heat collector tube: aluminum alloy2) Pipeline of ... collector tube: copper pipe3) Size of vacuum tube: 47mm x 1,500mm , 58mm x 1800mm4) Volume of tank: 150L, 200L, 250L ... , double-function (supply both solar energy and electricity)9) This system can be used into open loop,close loop and drain ...