Absorbs solar energy converting into heat for use in water heating
Each evacuated tube consists of two glass tubes made from extremely strong borosilicate glass
Outer tube is transparent allowing light rays to pass through with minimal reflection
Inner tube is coated with special selective coating (Al-N/Al) which features excellent solar radiation absorption and minimal reflection properties
Top of two tubes are fused together and air contained in space between two layers of glass is pumped out while exposing tube to high temperatures
Evacuation of gasses forms vacuum
Vacuum in evacuated glass tube is less than 5 x 10-3Pa
Can only be reached and maintained over long period of time through specialized evacuation process in production resulting in almost total elimination of convection and conduction losses from tube
