... intro.The U pipe collector mainly includes: vacuum tube, U copper pipe model, aluminum fin, collector frame.The selective coating of ... tube will absorb the sunlight, converts solar energy into heat energy and transfers heat to copper U tube by an aluminum fin ... / Painted metal2) Material of collector frame: aluminum alloy3) Coil material: copper 4) Water capacity: 150L, 200L,300L, 450L,5) Pressure: 0 ...