Slot type light gathering type solar vacuum heat collecting pipe

Abstract

The invention relates to a slot type light gathering type solar vacuum heat collecting pipe. The slot type light gathering type solar vacuum heat collecting pipe comprises an outer glass cover pipe and an inner heat absorbing pipe. An inner pipe coating is arranged on the outer cylindrical face of the inner heat absorbing pipe. A cavity between the outer glass cover pipe and the inner heat absorbing pipe is vacuum annular space. A heat shielding plate is arranged in the vacuum annular space. The side face, corresponding to the inner heat absorbing pipe, of the heat shielding plate is a reflection face, and the side face, corresponding to the outer glass cover plate, of the heat shielding plate is an absorption face. The inner surface of the heat shielding plate has the properties of high reflectivity and low emissivity in an infrared band, the outer surface of the heat shielding plate is coated with a selective absorption coating and has the properties of high absorptivity in the solar radiation wave band of 0.2-3 microns and low emissivity in the infrared wave band larger than 3 microns. The external radiation heat loss of the inner pipe of the vacuum heat collecting pipe under the medium-high temperature heat collecting situation can be greatly reduced, and the heat collecting efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of solar light and heat utilization, and relates to a solar heat collecting element, in particular to a groove-type concentrating solar vacuum heat collecting tube. Background technique [0002] Since the solar vacuum heat collector has the characteristics of simple structure, excellent performance, advanced and reliable production technology, and is especially suitable for mass production, it is widely used in practical applications, especially in trough solar thermal power generation systems. [0003] There is a vacuum layer between the inner tube and the outer tube of the solar vacuum heat collector tube, so the heat in the inner tube does not lose through air convection. However, heat can be transferred between the inner tube and the outer tube by radiation, resulting in heat loss. Since the outer wall of the inner tube of the solar vacuum heat collection tube is coated with a solar selective absorption...

AI Technical Summary

Problems solved by technology

At the same time, the emissivity of the inner tube at medium and high temperatures will reach 10%, resulting in greater heat loss from the inner tube

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