Solar cascade heat collecting system

Abstract

The invention discloses a solar cascade heat collecting system which comprises a working medium and at least two heat collecting sections. Each heat collecting section comprises at least one focusingheat collecting module, and the working medium is successively heated by the heat collecting sections. An intermediate heat collecting section is the focusing heat collecting module based on a Fresnellens field, and a high heat collecting section is the focusing heat collecting module based on a disc lens field. The solar cascade heat collecting system is coupled in this way. Compared with a conventional tank type solar system, the outlet temperature of fused salt can be increased in a condition that the heat losses of the heat collectors are same or lower. Compared with a tower type solar system, the system efficiency of the lens field can be improved and the construction cost of the lens field can be lowered in a condition of a same fused salt outlet temperature.

Description

technical field [0001] The invention relates to a solar heat collection system, in particular to a solar cascade heat collection system. Background technique [0002] The solar energy system includes a working medium and a concentrating and heat-collecting module, wherein the concentrating and heat-collecting module includes a concentrator and a heat collector. The function of the concentrator is to focus the parallel rays from the sun. In the process of concentrating, the solar radiation energy with low energy density is concentrated on the small receiving surface in the heat collector to realize the conversion of the operating fluid from low-grade heat energy to high-grade heat energy. The function of the heat collector is to convert the light reflected and focused by the concentrator from radiant energy into heat energy, so that the temperature of the working fluid flowing through the heat collector is increased. [0003] According to the shape of the light spot focused...

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Problems solved by technology

[0005] In addition, in the point-focused concentrator, the tower concentrator needs to build a tower, the economic cost is high, and the cosine efficiency caused by the solar motion needs to be considered, resulting in a decrease in the optical efficiency of the concentrator system; in comparison, The dish concentrator has a large concentrating ratio and high system efficiency. However, due to the continuous movement of the heat absorber due to the focus movement, it is usually not suitable for series and parallel connections; due to the limited load capacity of the support system, the mirror area cannot be set too large , so the power of a single dish concentrator for heat collection is usually small

The above two points make the traditional dish system cannot be used in large-scale solar thermal power plants

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