Modeling Method of Compound Parabolic Concentrator for Linear Fresnel Concentrating and Heat Collecting System Based on Matlab

Abstract

The invention relates to a modeling method for a compound parabolic concentrator (CPC) for a linear Fresnel light condensing and heat collecting system on the basis of matlab. The modeling method comprises the following steps: 1, determining the maximum receiving half angle theta c of the CPC; 2, using an outer diameter circle of a metal inner pipe of a vacuum heat collecting tube as a base circle of an involute; 3, rotating the involute by an angle alpha by using a circle center O as the center, so that a point C on the involute, which meets the condition that t=t0, is positioned on a center shaft of the CPC and the distance between the point C and the metal inner tube of the heat collecting tube is the sum of the distance between the point and a glass outer tube of the heat collecting tube and the distance between the glass outer tube and the metal inner tube of the heat collecting tube; 4, using a point on the involute, which meets the condition (refer to the specification), as a junction point of an involute CFB and a parabola A; 5, rotating the parabola by an angle theta c around the vertex of the parabola to enable the parabola to pass through a left junction point FB and using a right junction point FA as a focus to obtain a parabolic equation; 6, carrying out simulating calculation on a relation of a convergence rate and an intercepting ratio of the CPC by utilizing a ray tracing method, and selecting the suitable intercepting ratio.

Description

technical field [0001] The invention relates to a modeling method of a compound parabolic concentrator, in particular to a modeling method of a CPC (Compound Parabolic Concentrator: CPC) for a linear Fresnel type concentrating heat collection system based on matlab software. Background technique [0002] The structure of an ideal single-tube compound parabolic concentrator (Compound Parabolic Concentrator: CPC) is as follows figure 1 shown. A and B are two parabolas symmetrical about the central axis of CPC, F A and F B are the foci of A and B respectively, aF A and bF B Parallel to the principal axes of parabolas B and A respectively, the included angle is the maximum acceptance angle 2θ of CPC c . f B C. CF A It is two sections of involutes with the outer circle of the heat-absorbing tube as the base circle, which are also symmetrical about the central axis of the CPC. From the nature of the involute of the circle, it can be seen that the light from any direction ...

AI Technical Summary

Problems solved by technology

[0003] The solar vacuum heat collection tube used in the linear Fresnel concentrating heat collection system is covered with a glass outer tube outside the metal inner tube coated with a high-temperature resistant selective absorption film, and due to installation requirements, the glass outer tube of the heat collection tube must be in contact with the CPC tip. Therefore, the ideal CPC cannot be used in practice (the collector tube is close to the tip)

In addition, the existing design cannot perform optical simulation, and thus cannot realize an optimized design. The design cycle is long and the cost is high.

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