Graphite-glass vacuum thermal-collecting tube

Abstract

The invention discloses a graphite-glass vacuum heat collection tube, which belongs to the field of solar heat collector. The heat collection tube is characterized in that the device comprises an external glass tube, an internal graphite tube, an elastic support and a selective coating. The elastic support is arranged between the external glass tube and the internal graphite tube, and an upper port of the external glass tube is welded and connected to form closed space which is vacuumized. The external surface of the internal graphite tube is coated with solar energy selective absorption paint through spraying. The external glass tube is made of borosilicate glass. The graphite-glass vacuum heat collection tube has the advantages that the graphite tube facilitates the improvement of the heat transfer performance and heat collection efficiency of the heat collection tube; simultaneously the graphite tube is easily welded with the glass tube without the problem that welding seams are easy to crack during use, thereby easily keeping the vacuity of the heat collection tube persistently, and improving the heat collection performance of the solar heat collection tube.

Description

technical field [0001] The graphite-glass vacuum heat collecting tube of the invention belongs to the field of solar heat collectors and relates to solar heat collecting elements with high thermal conductivity. Background technique [0002] The solar collector tube is the core of the solar collector. At present, the solar collector tube is mainly a double-layer glass vacuum tube made of borosilicate glass 3.3, and the surface of the borosilicate glass is coated with a solar selective absorption coating. After the coating absorbs solar energy, the heat passes through the glass tube in the form of heat conduction. In this way, the thermal conductivity of the glass tube directly affects the heat collection performance and heat collection efficiency of the heat collection tube. Due to the relatively low thermal conductivity of glass (the thermal conductivity of borosilicate glass 3.3 is 1.2W / (m·℃)), a metal-glass vacuum heat collector with a metal tube as the inner tube appeare...

AI Technical Summary

Problems solved by technology

Due to the relatively low thermal conductivity of glass (the thermal conductivity of borosilicate glass 3.3 is 1.2W / (m·℃)), a metal-glass vacuum heat collector with a metal tube as the inner tube appeared, but due to the expansion coefficient of the metal The expansion coefficient is larger than that of glass, so it is difficult to deal with the welding problem of glass tubes and metal tubes, so it is difficult to ensure the vacuum degree of metal-glass vacuum tubes for a long time

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