The glass vacuum heat-accumulation tube is composed of inner and outer glass layers made of borosilicate glass, which can resist the impact of heat, cold and hailstone. It is highly vacuum between the two layers. The magnetic-control splashing vacuum chroming technique is applied to coat on the outer side of the inner layer a film, which can absorb the solar heat in the maximum, and reduce the heat loss to the minimum. The service life of the tube is over 15 years. The result of single tube test shows the water in the tube can reach boiling point in about two hours in a fine day when the surrounding temperature is about-18c. The tube diameter may range between 47mm and 1000mm. It's also acceptable to produce according to the specific requirements. These tubes are proved to be the ideal key parts for solar energy water heater factories.
In each winter day, 50Kgs of hot water (over 45c) can be supplied from the water heaters installed with lm area of the tubes in Beijing area. If in Spring, Summer or Autumn, the hot water supply way range between 100Kg/m and 150kg/m, and the water temperature can be much higher. The 1.5m long vacuum tube can absorb 1.27 times as much heat as the 1.2m tube. The heat efficiency of the tube is not lower than 42%, and the heat-loss coefficient is not higher than 5w/m. C.