heat pipe solar energy collector 1.Higher efficiency 2.Hot ... 4.ISO9001, CE Heat pipe vacuum tube solar thermal collector1. Features(1)High efficiency vacuum tube with selective coating, absorptivity arrives ... 11kg/cm2;(4)No water flow in vacuum tube, no water scale, no tube explosion, even at -40°C;(5) ... . It can still working even several of the vacuum tubes broken, maintenance can be done no need ...