... Vacuum Tube Solar Collector Features: 1) Reliable and efficient twin-glass solar tubes; 2) Copper heat pipes for rapid heat transfer ... -SOLAR KEYMARK,SRCC,EN12975-SOLAR KEYMARK,SRCC, Material Vacuum tubehigh borosilicate glass(58mm*1800mm)CoatingSS-CU-AIN/ALNHeat pipe materialTU1 copperHeat pipe ...