vacuum tube solar collector 1Easy install and operation 2Well wind, ... Sunrise compact pressurized vacuum tube solar collector Features:1. This system consists of solar vacuum tube, heat pipe, water ... heat preservation.Working Principle: Compact heat pipe pressure solar water hater is heat pipe, The heat pipe ... mm polyurethane foam.5. Stand angle: 15 degree, 20 degree, 25 degree, 30 degree, 38 degree, 45 ...