CN108775718A - The linear Fresnel mirror design method of biaxial tracker maximum focusing ratio - Google Patents

Abstract

The invention relates to a method for designing a linear Fresnel reflector with a maximum concentration ratio of a dual-axis tracker. The corresponding relationship between the angle between the mirror and the mirror field plane and the connection line between the collector center and the mirror center and the mirror field plane is obtained according to the law; the linear Fresnel reflector is obtained according to the triangle sine law Width; determine the horizontal distance between the second linear Fresnel reflector and the central axis of the collector according to the horizontal distance between the first linear Fresnel reflector and the central axis, and so on. The present invention accurately calculates the position parameters, width, and inclination angle of each linear Fresnel reflector in the mirror field, thereby utilizing the mirror field space to the greatest extent to realize the maximum concentration ratio, and maximizing the use of sunlight in the limited space , improved heat collection performance.

Description

Design method of linear Fresnel mirror with maximum concentration ratio for dual-axis tracker

technical field

The invention relates to a design method of a linear Fresnel reflector with a maximum concentration ratio of a biaxial tracker, and belongs to the field of geometric optics.

Background technique

Energy is the driving force behind the development of human society and the basis for human survival. Due to the shortage of energy sources, the development of new energy sources and new energy technologies has become a problem and challenge that countries all over the world must face in pursuit of sustainable development.

As a renewable clean energy source, solar energy contains enormous energy, and all countries in the world attach great importance to the research and development of solar energy utilization technology. Solar energy utilization technology refers to the use of solar collectors to collect, convert, and store solar radiant energy for use by users. The conversion methods mainly include solar photoelectric conversion and solar photothermal conversion. The most common way of utilization is solar thermal utilization. A solar collector is a device that converts solar energy into working fluid energy. The linear Fresnel reflective collector is a kind of linear collector. Compared with the trough collectors that have been commercially used, the linear Fresnel reflector has low cost, high site utilization, and high reflectivity. The mirror wind load is low, the control system is simple and so on. However, a technical problem of linear Fresnel reflectors is that adjacent mirrors have shadow and occlusion problems, which limits the commercial utilization of linear Fresnel reflectors.

Contents of the invention

In order to solve this problem, the present invention provides a method based on the linear Fresnel reflector on the dual-axis tracker to obtain the maximum concentration ratio. Under the premise of not blocking the reflected light, the reasonable calculation of each linear Fresnel in the mirror field The width, inclination angle and distance between adjacent mirrors can be adjusted to achieve the maximum concentration of light in a limited space.

A method for designing a linear Fresnel reflector with a maximum concentration ratio of a dual-axis tracker, comprising the following steps:

1) Determine the horizontal distance between the first linear Fresnel reflector and the central axis of the collector as Q ₁ , and the inclination angle α ₁ of the first linear Fresnel reflector, where the inclination angle is linear Fresnel The angle between the lens of the mirror and the mirror field plane;

2) According to the law of reflection, obtain the corresponding relationship between the inclination angle α _n of the nth linear Fresnel reflector and the angle β _n between the connection line between the center of the collector and the center of the lens and the plane of the mirror field;

3) obtain the width L _n of the nth linear Fresnel reflector according to the triangular sine law;

4) The horizontal distance Q ₁ between the first linear Fresnel reflector and the central axis of the collector determined according to step 1) and the inclination angle α ₁ of the first linear Fresnel reflector, combined with step 2) and 3) Calculate the horizontal distance Q ₂ between the second linear Fresnel reflector and the central axis of the collector, the width L ₂ of the second linear Fresnel reflector and the inclination angle α ₂ , and so on, the nth linear Fresnel reflector The horizontal distance Q _n of the Fresnel reflector to the central axis of the collector, the width L _n and the inclination angle α _n are determined by the horizontal distance Q _n- The inclination angle α _n-1 of the ₁ and n-1th linear Fresnel mirrors is determined.

Preferably, in step 2), sunlight is vertically incident on the mirror field, and the inclination angle α _n of the nth linear Fresnel reflector corresponds to the angle β _n between the line connecting the center of the collector and the center of the lens and the plane of the mirror field The relationship is shown in formula (1):

Preferably, in step 3), the width L _n of the nth linear Fresnel reflector is calculated according to the triangular sine law, as shown in formula (2): which is Among them, L ₀ is half of the width of the dual-axis tracker, and n≥1.

Preferably, it is characterized in that in step 4), set the horizontal distance between the first linear Fresnel reflector and the central axis of the heat collector as Q ₁ , and set the distance between the second linear Fresnel reflector and the central axis of the heat collector The horizontal distance is Q ₂ , and so on, the horizontal distance between the n-1th linear Fresnel reflector and the central axis of the collector is Q _n-1 , and the n-th linear Fresnel reflector and the collector The horizontal distance of the central axis of the heater is Q _n . On the premise that the lens width of the nth linear Fresnel reflector does not block the light reflected by the n-1th linear Fresnel reflector, according to the following formula (1) (2)(3)(4) The calculated lens parameters of the linear Fresnel reflector maximize the concentration ratio, and the formulas (3) and (4) are as follows:

Among them, n>1;

Among them, H is the vertical distance between the collector and the mirror field plane.

Beneficial effects: the present invention provides a design method for a linear Fresnel reflector with a maximum light concentration ratio of a dual-axis tracker, which utilizes the mirror field space to the greatest extent to achieve a maximum light concentration ratio, so that sunlight in a limited space can be obtained The maximum utilization improves the heat collection performance. At the same time, the lens design is simple, the price is reasonable, and the device is easy to control, which is conducive to promoting the development of linear Fresnel heat collectors.

Description of drawings

Fig. 1 is a design explanatory diagram of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in the application, the technical solutions in the embodiments of the application are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the application, and Not all examples. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

The linear Fresnel reflector device with the maximum concentration ratio of the dual-axis tracker includes a bracket, an angle steel, a holding piece, and a linear Fresnel reflector. As shown in Figure 1, the design method of the linear Fresnel reflector includes the following step:

1) Determine the horizontal distance between the first linear Fresnel reflector and the central axis of the collector as Q ₁ , and the inclination angle α ₁ of the first linear Fresnel reflector, where the inclination angle is linear Fresnel The angle between the lens of the mirror and the mirror field plane;

2) According to the law of reflection, the corresponding relationship between the inclination angle α _n of the nth linear Fresnel reflector and the angle β _n between the line connecting the center of the collector to the center of the mirror and the plane of the mirror field is obtained, as shown in formula (1) : where n≥1;

3) Obtain the width L _n of the nth linear Fresnel reflector according to the triangular sine law, as shown in formula (2): which is Among them, L ₀ is half of the width of the dual-axis tracker, n≥1;

4) Set the horizontal distance between the first linear Fresnel reflector and the central axis of the heat collector as Q ₁ , and set the horizontal distance between the second linear Fresnel reflector and the central axis of the heat collector as Q ₂ , since the first When the two lenses move to the left from the position of the first lens, the width of the lens changes from blocking the reflected light at the end of the first lens to not blocking the reflected light at the end of the first lens, without considering the occlusion Next, we choose the special position where the width of the second lens just does not block the reflected light at the end of the first lens for calculation, and we get And according to formula (2), we can get, Make formulas (5) and (6) equal to get By analogy, set the horizontal distance between the n-1th linear Fresnel reflector and the central axis of the collector as Q _n-1 , and set the horizontal distance between the n-th linear Fresnel reflector and the central axis of the collector is Q _n , under the premise that the lens width of the nth linear Fresnel reflector does not block the light reflected by the n-1th linear Fresnel reflector, the following formula is satisfied: and Among them, H is the vertical distance between the heat collector and the mirror field plane; then according to the previous formulas (1) and (3), the inclination angle α and the distance Q of each linear Fresnel reflector can be calculated in turn.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (4)

1. The linear Fresnel reflector design method of the maximum concentration ratio of the biaxial tracker is characterized in that, comprising the following steps: 1) Determine the horizontal distance between the first linear Fresnel reflector and the central axis of the collector as Q ₁ , and the inclination angle α ₁ of the first linear Fresnel reflector, where the inclination angle is linear Fresnel The angle between the lens of the mirror and the mirror field plane; 2) According to the law of reflection, obtain the corresponding relationship between the inclination angle α _n of the nth linear Fresnel reflector and the angle β _n between the connection line between the center of the collector and the center of the lens and the plane of the mirror field; 3) obtain the width L _n of the nth linear Fresnel reflector according to the triangular sine law; 4) The horizontal distance Q ₁ between the first linear Fresnel reflector and the central axis of the collector determined according to step 1) and the inclination angle α ₁ of the first linear Fresnel reflector, combined with step 2) and 3) Calculate the horizontal distance Q ₂ between the second linear Fresnel reflector and the central axis of the collector, the width L ₂ of the second linear Fresnel reflector and the inclination angle α ₂ , and so on, the nth linear Fresnel reflector The horizontal distance Q _n of the Fresnel reflector to the central axis of the collector, the width L _n and the inclination angle α _n are determined by the horizontal distance Q _n- The inclination angle α _n-1 of the ₁ and n-1th linear Fresnel mirrors is determined. 2. the linear Fresnel reflector design method of the maximum concentration ratio of the biaxial tracker according to claim 1, is characterized in that: in step 2), sunlight is vertically injected into the mirror field, and the nth linear Fresnel The corresponding relationship between the inclination angle α _n of the reflector and the angle β _n between the line connecting the center of the collector and the center of the mirror and the plane of the mirror field is shown in formula (1): 3. the linear Fresnel reflector design method of the maximum concentration ratio of the biaxial tracker according to claim 2, is characterized in that, in step 3), calculate the nth linear Fresnel reflector according to the triangular sine law Width L _n , as shown in formula (2): which is Among them, L ₀ is half of the width of the dual-axis tracker, and n≥1. 4. the linear Fresnel reflector design method of the maximum concentration ratio of the biaxial tracker according to claim 3, is characterized in that, step 4) establishes the first linear Fresnel reflector and the heat collector center The horizontal distance of the axis is Q ₁ , and the horizontal distance between the second linear Fresnel reflector and the central axis of the collector is Q ₂ , and so on, assuming that the n-1th linear Fresnel reflector and the collector The horizontal distance of the central axis of the collector is Q _{n -1} , and the horizontal distance between the nth linear Fresnel reflector and the central axis of the collector is Qn, and the lens width of the nth linear Fresnel reflector does not block Under the premise that the n-1th linear Fresnel reflector reflects light, the lens parameters of the linear Fresnel reflector calculated according to the following formula (1)(2)(3)(4) make the light concentrating than the maximum, formulas (3) and (4) are as follows: Among them, n>1; Among them, H is the vertical distance between the collector and the mirror field plane.