Solar energy water heater tube (vacuum tube) is made of what material?
The 3.3 high borosilicate glass with strong external striking ability (the coefficient of thermal expansion of the wire is (3.3 * 0.1) * 10-6/K, which is a low expansion rate and high temperature resistance
High strength, high hardness, high light transmittance and high chemical stability of special glass materials, from the inside and outside the tube vacuum (vacuum degree is generally 5 x 10-2) coating (aluminum - nitrogen - aluminum, copper - nitrogen - aluminum, etc.).
High borosilicate 3.3 glass, which is a blue or red material is a heat absorbing coating, there are nitrogen alumina, copper, stainless steel, etc., are some of the very good heat absorbing metal coating
