CN201096909Y - A solar focusing reflective board - Google Patents

Abstract

The utility model discloses a solar energy light condensing reflection board in the solar energy heat collecting device field. The shape of the light reflecting surface of the light condensing reflection board is a spatial curved surface, the cutting line of the spatial curved surface is a symmetrical curved line that the vertical line of the polar axis which can pass the pole in the polar coordinates system is taken as the symmetric axis, the cutting line at one side of the symmetric axis is composed of more than three sections of parabolas which are connected in sequence, and each section of parabola corresponds to the best sunlight reflecting value of a time quantum. The entire solar energy light condensing reflection board can get the best condensing effect, and the thermal efficiency can be enhanced; the solar energy light condensing reflection board can be taken as the light condensing reflection board of each non-tracking type solar energy heat collector, the light condensing and light reflecting board in the heat collecting pipe, and the light condensing reflection board of the non-tracking type solar oven, etc.

Description

A solar concentrating reflector

technical field

The utility model relates to solar heat utilization technology.

Background technique

Use the concentrating reflector to reflect a larger area of sunlight to the heat-collecting device to enhance the heat-collecting effect and increase the temperature of the medium in the heat-collecting device. Many people have achieved research results on this subject, and some use V-shaped reflectors Some of them use barrel-shaped reflectors whose cross-sections are circular arcs, and arc-shaped reflectors whose cross-sections are arcs with different curvature radii. Open-line reflectors and more.

As a non-tracking concentrating reflector, due to the large change in the incident angle of sunlight during the day, there is still a lot of sunlight that cannot be reflected to the heat collecting device, and the satisfactory concentrating effect cannot be achieved, and a part of the strong light is often lost. And some weak light is captured.

Utility model content

The purpose of the utility model is to design a solar energy concentrating reflector, which can reflect the light reaching the reflector to the surface of the heat collecting device to the greatest extent.

The purpose of this utility model is achieved in this way: a solar energy concentrating reflector, the shape of the reflective surface of the concentrator reflector is a space curved surface, and the section line of the space curved surface is the plane polar coordinate system passing through the pole The vertical line of the polar axis is the symmetric curve of the symmetry axis, and the section line on one side of the symmetry axis is composed of more than three sequentially connected parabolas L ₀ , L ₁ , L ₂ ... L _i , and the focus of each parabola is located at The poles of the plane polar coordinate system, each parabola L _i satisfy the following equation:

Among them, i=0, 1, 2, 3, 4, 5...;

ρ is the distance from the point on the parabola to the pole, that is, the polar diameter;

_Pi is the focal parameter of the parabola, which is twice the distance from the apex of the corresponding parabola to the focal point;

0 is the polar or argument angle of a point on a parabola in the polar coordinate system, 90°<θ≤270°;

The deflection angle of the parabolic axis (that is, the symmetric axis of the parabola) refers to the angle at which the parabolic axis rotates counterclockwise with the pole as the center;

Intersection A ₁ of L ₁ and L ₀ (ρ ₁ , θ ₁ )

Intersection A ₂ of L ₂ and L ₁ (ρ ₂ , θ ₂ )

Intersection point A _i (ρ _i , θ _i ) of L _i and L _i-1

The angle between the axis of the parabola L ₀ (i.e. the axis of symmetry) and the vertical line of the polar axis of the plane polar coordinate system is 0, that is, the parabola L ₀ is not rotated, and the rotation angle  ₀ is 0;

The axis of the parabola L ₁ rotates counterclockwise relative to the axis of L ₀ , the center of rotation is the pole of the plane polar coordinate system, the angle of rotation is  ₁ , and the deflection angle is  ₁ ;

 ₁ corresponding to θ ₁ : Since the average incident angle of the relatively strong incident light at the arrival point (ρ ₁ , θ ₁ ) is represented by such a straight line, the angle between the straight line and the vertical line passing through the polar axis of the pole is  ₁ , that is to say,  ₁ is determined by physical parameters; deflection angle  ₂ ,  _i and so on; the vertical line of the polar axis passing through the pole is exactly the axis of parabola L ₀ ;

The deflection angle of parabola L ₂ is  ₂

The deflection angle of parabola L _i is  _i

The focal parameter P value of the adjacent parabola satisfies the following equation:

Among them: i=0, 1, 2, 3...

 ₀ = 0 0 < ₁ < ₂ < ₃ <...< _i .

The utility model adopts several sections of parabolas to form a reflective surface section line of a concentrating reflector in succession, and the incident rays of the sun parallel to any parabola axis can converge to the focal point of the corresponding parabola. At the focal point) the heat-collecting element itself has a certain volume, so the incident light from the sun whose angle with the corresponding parabola axis is less than a certain value can be reflected by the reflective surface of the parabola to the heat-collecting element. Relatively strong incident light within a certain time range can obtain the best light-concentrating effect compared to other shapes of light-concentrating reflective surfaces. Due to the distance between each parabolic segment and the focal point, the length of time to gather sunlight within a certain time range around noon and the starting time are different, but the incident light from the sun that arrives on the reflective surface of each parabolic segment is reflected and converged to the surface of the heat-collecting element during the whole period of time when the sunlight intensity is relatively strong, and its heat-collecting efficiency is high. Expensive tracking devices are necessary. Since the spatial curved surface described in the utility model is used as the reflective light-gathering surface because it is non-tracking, there is actually a certain amount of relatively weak sunlight that cannot be concentrated on the heat-collecting element in a day, but the spatial curved surface described in the utility model is used as the reflective surface. The non-tracking reflective light-gathering surface has the best light-gathering effect in theory, because any curved surface of the space curved surface described in the utility model can theoretically achieve that the incident light rays of the sun arriving on the reflective surface are within its During the whole period of time when the sunlight intensity is relatively strong, it is reflected and concentrated on the surface of the heat-collecting element, while other shapes of reflective and light-concentrating surfaces reflect and gather the incident light of the sun for the same period of time, but the light is not the strongest one in a day. light over time. The utility model can be used as the concentrating reflective plate of various non-tracking solar heat collectors, the concentrating reflective plate in the heat collecting tube, the concentrating reflective plate of the non-tracking solar cooker, and the like.

The space curved surface may have the following two structures. One is that the space curved surface is formed by stretching the section line along the vertical direction of the plane where it is located. The focal point of each section line is stretched into a straight line, and a solar heat collecting tube can be arranged along the straight line to make a non-tracking type solar heat collector. The second is that the space curved surface is formed by rotating the section line, and the rotation axis is the symmetry axis of the section line. Each section line has a common focal point (pole), and a heat collecting element can be arranged on the focal point to make a non-tracking solar cooker.

Description of drawings

Fig. 1 is a schematic diagram of the utility model;

Fig. 2 is the sectional schematic diagram of reflective surface;

Detailed ways

Example 1

As shown in Fig. 1, it is a kind of solar concentrating reflective plate, the shape of the reflective surface of the said concentrating reflective plate is a space curved surface, and the section line of this space curved surface is symmetrical with the polar axis perpendicular line passing through the pole in the plane polar coordinate system The symmetric curve of the axis is composed of three sections of parabola L ₀ , L ₁ , L ₂ ... L _i connected in sequence by the intercept line on one side of the symmetry axis. The focus of each parabola is located at the pole of the plane polar coordinate system. _Li satisfies the following equation:

Wherein, i=0, 1, 2, 3;

ρ is the distance from the point on the parabola to the pole, that is, the polar diameter;

_Pi is the focal parameter of the parabola, which is twice the distance from the apex of the corresponding parabola to the focal point;

θ is the polar or argument angle of a point on a parabola in the polar coordinate system, 90°<θ≤270°;

The deflection angle of the parabolic axis (that is, the symmetric axis of the parabola) refers to the angle at which the parabolic axis rotates counterclockwise with the pole as the center;

Intersection A ₁ of L ₁ and L ₀ (ρ ₁ , θ ₁ )

Intersection A ₂ of L ₂ and L ₁ (ρ ₂ , θ ₂ )

Intersection A ₃ of L ₃ and L ₂ (ρ ₃ , θ ₃ )

The angle between the axis of the parabola L ₀ (i.e. the axis of symmetry) and the vertical line of the polar axis of the plane polar coordinate system is 0, that is, the parabola L ₀ is not rotated, and the rotation angle  ₀ is 0;

The mathematical expression of L ₀ :

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; Sin\&theta;</span>}<span\; class="notranslate">\; ]</span>}{{\mathrm{<span\; class="notranslate">\; cos</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}$

For the concentrating reflector that is limited to be installed in the transparent circular glass tube, the chord length B ₁ B ₂ of the chord that the parabola L ₀ passes through the focal point and is perpendicular to the parabola axis can generally be used as the maximum width of the incident light family that wants to converge, Take B ₁ B ₂ =2P ₀ , P ₀ is also equal to twice the distance from the apex of the parabola L ₀ to the focal point; for a concentrating reflector with no limited space conditions, the maximum width of the incident light family to be converged can be greater than 2P ₀ .

The mathematical expression of L ₁ :

The axis of the parabola L ₁ rotates counterclockwise relative to the axis of L ₀ , the center of rotation is the pole of the plane polar coordinate system, the angle of rotation is  ₁ , and the deflection angle is  ₁ ;

 ₁ corresponding to θ ₁ : Since the average incident angle of the relatively strong incident light at the arrival point (ρ ₁ , θ ₁ ) is represented by such a straight line, the angle between the straight line and the vertical line passing through the polar axis of the pole is  ₁ , that is to say,  ₁ is determined by physical parameters; deflection angle  ₂ ,  _i and so on; the vertical line of the polar axis passing through the pole is exactly the axis of parabola L ₀ ;

The deflection angle of parabola L ₂ is  ₂

The deflection angle of parabola L _i is  _i

The focal parameter P value of the adjacent parabola satisfies the following equation:

Where: i=0, 1, 2, 3

_0 ＝00< _1 < _2 < _3 .

The space curved surface is formed by stretching the section line along the vertical direction of the plane where it is located.

On the parabola L _0, the opening angle of point A ₁ to the collector is ∠PA ₁ R=α, and the incident light rays reaching point A ₁ are distributed in the range of β angle, β>α, let A ₁ M be parallel to the parabola L ₀ axis, the collector can only receive the incident light that arrives at point A ₁ within the angle range less than or equal to α, assuming ∠PA ₁ Q=α, this is the strongest light that reaches point A ₁ within the range of angle α in one day, A ₁ N is the angle bisector of ∠PA ₁ Q, let ∠MA ₁ N= ₁ This means that the average incident angle of the strongest light that reaches point A ₁ and may be received by the collector in a day is parallel to the straight line A ₁ N represents the incident ray.

If we change the P value of a certain parabola passing through point A ₁ , the focus is still at point O and the axis of the parabola is rotated by  ₁ angle, so that the incident light within the range of ∠PA ₁ Q can be accurately reflected to ∠PA ₁ R range. The new parabola rotated by  ₁ angle with O point as the center is L ₁ parabola.

On the parabola point A ₁ to the left, the average incident angle of the incoming incident light is represented by the incident light parallel to the axis of the parabola L ₀ , so the leftward L ₀ parabola of point A ₁ is the best, No need to rotate.

On the parabola point A ₁ goes to the right and crosses A _2. A new parabola still rotates  ₂ with O as the focus, its focal parameter P is changed to P ₂ , and the new parabola is L ₂ . The same reason can also ensure that The strongest light that reaches point _A2 and has the conditions to be reflected on the heat collector with a certain space size is theoretically converged to the surface of the heat collector without omission.

By analogy, when the intercept line is composed of more than three parabolas, several points correspond to several optimal parabolas. A ₁ point is on the L ₁ parabola, A ₂ point is on the L ₂ parabola, A _i point is on the L _i parabola, if i is large enough, the following new curve can accurately gather as much sunlight as possible to the collector until To achieve the theoretically best convergence effect.

The new curve is formed by the following points and the following parabola continuation:

L ₀ -A ₁ (point)-L ₁ -A ₂ -L ₂ -A ₃ -……-A _i -L _i

If the value of i is large enough, the new curve above is indistinguishable from the new curve expressed by:

L ₀ -A ₁ (point)-A ₂ -A ₃ ……-A _i

In this way, the cross-section of the curved reflector can be composed of several parabolic segments, and each section of the cross-section on both sides of the Y axis is symmetrical to the vertical line passing through the origin and perpendicular to the polar axis, as shown in Figure 2, each section The reflectors correspond to the strongest incident light for a period of time, and their overall combination can obtain the best light-gathering effect. The space curved surface is formed by stretching the cross-section along the vertical direction of the plane where it is located. The focus of each cross-section of the curved reflector (that is, the common focus of each segment of the parabola) is stretched into a straight line. Solar thermal collector tubes can be set and can be made into non-tracking solar thermal collectors.

Example 2

Another kind of solar concentrating reflector, the shape of the reflective surface of the concentrator reflector is a space curved surface, and the section line of the space curved surface is a symmetric curve with the polar axis perpendicular line passing through the pole in the plane polar coordinate system as the symmetry axis , the space curved surface is formed by the rotation of the section line, and the rotation axis is the symmetry axis Y axis of the section line; the section line shape can still be shown in Figure 2, and the section line on one side of the symmetry axis consists of three The above sequentially connected parabolas L ₀ , L ₁ , L ₂ ... _Li are composed, the focus of each parabola is located at the pole of the plane polar coordinate system, and each parabola L _i satisfies the following equation:

Among them, i=0, 1, 2, 3, 4, 5...;

ρ is the distance from the point on the parabola to the pole, that is, the polar diameter;

_Pi is the focal parameter of the parabola, which is twice the distance from the apex of the corresponding parabola to the focal point;

θ is the polar or argument angle of a point on a parabola in the polar coordinate system, 90°<θ≤270°;

The deflection angle of the parabolic axis (that is, the symmetric axis of the parabola) refers to the angle at which the parabolic axis rotates counterclockwise with the pole as the center;

Intersection A ₁ of L ₁ and L ₀ (ρ ₁ , θ ₁ )

Intersection A ₂ of L ₂ and L ₁ (ρ ₂ , θ ₂ )

Intersection point A _i (ρ _i , θ _i ) of L _i and L _i-1

The angle between the axis of the parabola L ₀ (i.e. the axis of symmetry) and the vertical line of the polar axis of the plane polar coordinate system is 0, that is, the parabola L ₀ is not rotated, and the rotation angle  ₀ is 0;

The axis of the parabola L ₁ rotates counterclockwise relative to the axis of L ₀ , the center of rotation is the pole of the plane polar coordinate system, the angle of rotation is  ₁ , and the deflection angle is  ₁ ;

 ₁ corresponding to θ ₁ : Since the average incident angle of the relatively strong incident light at the arrival point (ρ ₁ , θ ₁ ) is represented by such a straight line, the angle between the straight line and the vertical line passing through the polar axis of the pole is  ₁ , that is to say,  ₁ is determined by physical parameters; the vertical line passing through the polar axis of the pole is just the axis of the parabola L ₀ ;

The deflection angle of parabola L ₂ is  ₂

The deflection angle of parabola L _i is  _i

The focal parameter P value of the adjacent parabola satisfies the following equation:

Among them: i=0, 1, 2, 3...

 ₀ = 0 0< ₁ < ₂ < ₃ <...< _i ;

Each section parabola section has a common focal point (pole), and a heat collecting element can be arranged on the focal point to make a non-tracking solar cooker.

Claims (3)

1, a kind of solar concentrating reflective plate, it is characterized in that: the reflective surface shape of described concentrating reflective plate is a space curved surface, and the section line of described space curved surface is the vertical direction of the polar axis passing pole point in the plane polar coordinate system. The line is a symmetric curve of the axis of symmetry, and the section line on one side of the axis of symmetry is composed of more than three consecutive parabolas L ₀ , L ₁ , L ₂ ... L _i , the focus of each parabola is located in the polar coordinate system of the plane pole, each segment of parabola L _i satisfies the following equation: Among them, i=0, 1, 2, 3, 4, 5...; ρ is the distance from the point on the parabola to the pole, that is, the polar diameter; _Pi is the focal parameter of the parabola, which is twice the distance from the apex of the corresponding parabola to the focal point; θ is the polar or argument angle of a point on a parabola in the polar coordinate system, 90°<θ≤270°;  is the deflection angle of the parabolic axis, which refers to the angle that the parabolic axis rotates counterclockwise with the pole as the center; Intersection A ₁ of L ₁ and L ₀ (ρ ₁ , θ ₁ ) Intersection A ₂ of L ₂ and L ₁ (ρ ₂ , θ ₂ ) Intersection point A _i (ρ _i , θ _i ) of L _i and L _i-1 The angle between the axis of the parabola L ₀ and the vertical line of the polar axis of the plane polar coordinate system is 0, at this time, the parabola L ₀ is not rotated, and the rotation angle  ₀ is 0; The axis of the parabola L ₁ rotates counterclockwise relative to the axis of L ₀ , the center of rotation is the pole of the plane polar coordinate system, the angle of rotation is  ₁ , and the deflection angle is  ₁ ;  ₁ corresponding to θ ₁ : the average incident angle of the relatively strong incident light at the arrival point (ρ ₁ , θ ₁ ) is represented by the following line, the angle between this line and the vertical line passing through the polar axis of the pole is  ₁ ; Deflection angle  ₂ ,  _i and so on; the vertical line passing through the polar axis of the pole is just the axis of parabola L ₀ ; The deflection angle of parabola L ₂ is  ₂ The deflection angle of parabola L _i is  _i The focal parameter P value of the adjacent parabola satisfies the following equation:

Among them: i=0, 1, 2, 3...  ₀ = 0 0 < ₁ < ₂ < ₃ <...< _i . 2. The solar concentrating reflector according to claim 1, wherein the space curved surface is formed by stretching the section line along the vertical direction of the plane where it is located. 3. The solar concentrating reflector according to claim 1, wherein the space curved surface is formed by rotating the section line, and the rotation axis is the symmetry axis of the section line.

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