>Heat pipe vacuum tube for solar water heating system
>Working without water inner tubes

Heat pipe vacuum tube has the following advantages:
1) It perfectly solves the problem of which can't run if one of the tubes is out of work
2) It prevents the tube from being easily broken caused by the volume expansion when the water in tube freezes in frigid season
3) There is no water in the tubes, so it is successfully prevented the defects of tubes' broken and lower power output caused by water fouling and deposits of mud and sand
4) Adopt high efficient selective absorptive coatings and low reflection ratio ensure the tube to get higher power output in cloudy weather and in moist area, especially in winter.