solar collector tube

Vacuum tube is inosculated  by  two  glass tube at one end.inner tube with a selective coating, it can absorb the solar energy, prevent heat loss.Underpressure the air to form vacuum between the two tubes , prevent the conduction and convection heat loss.These tubes have high efficiency in the cloudy weather and low temperature conditions.This is because the tube material is glass, therefore the possibility of leakage be reduced to a minimum. Glass vacuum tube have a wide range of uses, including the DC or mixed with the heat pipe. Although the efficiency of the vacuum tube is lower than cryotron, but cheaper.