Heat absorbing solar water heater vacuum tubes
1.8 meter/58 mm or 1.5 meter/47 mm
99% heat absorption efficiency
Lifetime greater than 10 years
Vacuum ensures no heat loss
Withstands 1/4 inch hailstones
Double walled evacuated tubes

High efficiency glass tubes may be used with metal heat pipes and fin inserts or passive solar water heaters that circulate water directly in the evacuated tubes. Solar energy is trapped on the black absorption surface, which is deposited on the inner glass using thin-film technology.