Features:

Kaidun sun tube is made of dual borosilicate glass tubes,the space between the two tubes is evacuated. The AL/N/AL selectivecoating on the outer wall of the inner tube absorbs sunshine andtransforms it into heat which in turn heats the cold water in theinner tube. When the water in the tube is heated, its density willdecrease and will go upward into the tank; meanwhile the cold waterin the tank will flow down into the tube due to its greaterdensity. Thus, the circulation and heat-exchanging in the system iscompleted. The color of the inner tube is black-grey. This vacuumtube has a high heat-efficiency and low price. It is suitable inareas with winter temperature above–20°C.

Specification of KD-VT-AG

A) Structure: all glass concentric dual layertube

B) Glass material: borosilicate

C) Absorptance: >0.90

D) Emittance: <0.08 (80°C)

E) Vacuum: <5x10-5 Pa

F) Stagnation: >230  C/KW

G) Average Heat Loss: <0.8

H) Service life: more than 15 years