Hierarchical cavity type solar heat absorber and heat exchange system

Abstract

The invention discloses a hierarchical cavity type solar heat absorber which comprises a solar reflector and heat absorbers, and is characterized in that the heat absorbers comprise an independent primary heat absorber and an independent secondary heat absorber, namely a primary heat absorber with an evaporation heating surface and a secondary heat absorber with an overheating heating surface, wherein the evaporation heating surface and the overheating heating surface are connected through a steam pocket. The invention has the beneficial effects that as condensers and the heat absorbers are arranged in a targeted manner, the heat-flow density can be effectively distributed, the safety of the heat absorbers is ensured and the operation difficulty is reduced; the tube wall thickness of the heat absorbers can be properly increased so as to improve the pressure rating of a working medium and the unit efficiency; and the condensers are arranged in groups and the heat-flow density of each part in a heat receiver is controlled within a reasonable range so that temperature near the heat receiver can be reduced and the solar heat radiation loss after focusing is reduced.

Description

technical field [0001] The invention relates to a device for targetedly improving the efficiency and safety of a solar thermal power plant, in particular to a solar heat absorber used in a solar thermal power plant. Background technique [0002] Solar thermal power plants use numerous mirrors to focus solar radiation energy, and then use the focused radiation energy to heat the medium to generate electricity. This kind of thermal power station can exist independently from the solar power generation circuit, and can also form a thermal power station together with the water-steam power generation circuit using fossil fuels. The solar power generation circuit is composed of different types of concentrators, heat sinks and heat exchangers. The fossil fuel water-steam power generation circuit consists of an oil / gas boiler and a heat exchanger. Here, the solar power generation circuit is composed of many concentrators that focus the sun's rays on the heat absorber located in the...

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Problems solved by technology

[0003] Due to the uncontrollable characteristics of sunlight and the limitation of existing heat collector technology, the heat absorber in the existing solar power generation circuit often operates in a large range of radiation fluctuations. If the heat absorber is not properly designed, There are many problems in the efficiency and safety of the power station; the main manifestations are: ①. The heat energy of all collectors is concentrated in a small range, and the heat flux density in the cavity is too large, so the heat absorber must have a strong heat exchange ②, the temperature in the cavity is too high, which increases the heat loss of the light boiler; ③, in order to ensure the safety of the heating surface in the high temperature cavity, the heat exchange capacity of the metal tube must be increased, which limits the heat exchange tube The wall thickness of the boiler limits the increase of boiler pressure parameters and reduces the efficiency of the unit; ④ Excessive heat flux design will seriously threaten the safety of the heat sink when the system fails

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