Novel disc type condenser

Abstract

The utility model discloses a novel disc condenser, which relates to the technical field of light-gathering solar photo-thermal utilization, and comprises a reflecting mirror and a receiver, the reflecting mirror is formed by splicing a plurality of spherical mirrors with fan-shaped light-passing surfaces, the fan-shaped spherical mirrors form a plurality of rings, and the receiver is connected with the reflecting mirror. The center of each fan-shaped spherical mirror reflects incident sun center light to a common focus, the receiver is a flat receiver or a cavity receiver and is installed on the common focus, and one of the optimized technical schemes is that the curvature radius of the spherical mirror is equal to two times of the distance from the center of the fan-shaped spherical mirror to the common focus, and the curvature radius of the spherical mirror is equal to two times of the distance from the center of the fan-shaped spherical mirror to the common focus. The center of the spherical mirror is on a reference spherical surface, and the curvature diameter of the reference spherical surface is equal to the focal length of the system, so that point focusing can be realized by using earth axis tracking, the reliability is improved, the cost is reduced, and the efficiency is only 0.29% lower than that of an actual paraboloid disc type system.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of novel dish type concentrators, and specifically to a novel dish type concentrator. BACKGROUND

[0002] Concentrated solar thermal power is a technology that uses concentrated solar technology to focus a large amount of low-density solar energy onto a small area, creating high-density solar energy, which can generate high-temperature heat energy for solar thermal power generation. It is the most promising technology to replace coal-fired power plants. The main concentrated solar technologies currently available are tower, trough, linear Fresnel, and dish.

[0003] Typically, dish-type solar concentrators use a rotating parabolic mirror as the primary mirror, and a two-way tracking device is used to ensure that the incident sunlight always enters the dish mirror at an angle of about 0 degrees. The dish mirror focuses the sunlight onto the focal point, and a receiver or direct heating medium is used to drive the engine installed at the focal point to generate electricity. This method has the largest cosine factor and the highest efficiency, making it one of the most promising concentrated solar technologies.

[0004] However, the rotating parabolic mirror used in the typical dish system is difficult to manufacture, costly, and has large errors, which leads to a decline in system performance. The simplest solution is to use small-area flat mirrors to form a dish system mirror, but the concentration ratio is significantly reduced, and the performance is much worse than that of the rotating parabolic dish system. The second solution is to use multiple spherical mirrors to form a mirror, simulating a rotating parabolic mirror. For example, patent CN201220201616.1 uses square spherical mirrors to form a mirror, which can reduce the difficulty and cost of mirror manufacturing. Literature also uses regular hexagonal and triangular spherical mirrors, but they introduce spherical aberrations, including spherical aberrations, meridional and sagittal aberrations, which still significantly reduce system performance. The third solution is to use a spherical mirror as the primary mirror. In the field of astronomical telescopes, this has become one of the main choices for many giant telescopes, which can significantly reduce the difficulty and cost of primary mirror manufacturing. However, it often requires the use of multiple secondary mirrors to correct spherical and coma aberrations, making the system structure very complex, increasing the difficulty and cost of manufacturing, and making it difficult to apply to the solar energy field. Patent CN200610041392.1 uses a spherical mirror instead of a rotating parabolic mirror and uses a tubular receiver with a length equal to half the radius of the spherical mirror, which significantly reduces the concentration ratio and performance of the spherical mirror. CN201610278112.2 and CN201610278111.8 use multiple aspherical mirrors to construct an off-axis dish system, which increases the difficulty and cost of manufacturing.

[0005] It is a common method to use double mirrors and multiple mirrors to build a telescope in the field of astronomy. In the field of solar energy, the multiple mirror system is complex and difficult to implement technically. For example, the double mirror system designed in Pan Qikun et al. High-magnification solar concentrator based on Cassegrain structure (China Optics, 2012, Vol 5, No 4) uses a photovoltaic cell as a receiver, a rotating parabolic mirror as a primary mirror, and a rotating hyperboloid as a secondary mirror. Only spherical aberration is eliminated, and the theoretical concentration ratio is only 550 times. Moreover, the processing difficulty is great, and the actual concentration ratio is 500 times. The performance is lower than that of the traditional dish system.

[0006] Recently, one of the solutions proposed by us, as described in patents CN202320526509.4 and CN202310842421.8, is to use annular spherical mirrors to splice to form a primary mirror. The centers of the mirrors form a parabolic surface and a spherical surface, respectively. The processing difficulty is low, the precision is high, the slope error of the reflecting surface is reduced, the spot size is reduced, and the concentration ratio is improved. However, the design still has shortcomings. Our recent research shows that the aberration is large. The utility model is further improved on the basis of the design and proposes to use a fan-shaped spherical mirror to splice to reduce the aberration of each spliced spherical mirror. A technical solution for achieving point focusing using single-axis tracking is also proposed, thereby further simplifying the structure and improving the performance. Utility model content

[0007] The utility model aims at providing a novel dish concentrator, which has a high concentration ratio, a high optical efficiency, a low processing difficulty, and a low cost, so as to solve the above problems.

[0008] To achieve the above-mentioned purpose, the utility model provides the following technical scheme.

[0009] A novel dish concentrator comprises a mirror and a receiver, wherein the mirror is composed of multiple spherical mirrors with fan-shaped light transmission surfaces, the centers of the spherical mirrors reflect the central light of the sun to a common focal point, the receiver is a flat plate receiver or a cavity receiver, and is installed on the common focal point. The distance from the center of the fan-shaped spherical mirror to the common focal point is set to , and the radius of curvature of the spherical mirror is set to , satisfying .

[0010] The reference surface composed of the centers of all the spherical mirrors is a rotationally symmetrical surface, which can be a plane, a spherical surface, a rotating parabolic surface, an ellipsoidal surface, a hyperboloidal surface, or other rotationally curved surfaces.

[0011] The mirror and the receiver are installed above a two-axis tracking device. When the receiver uses a cavity receiver, a spherical segment transparent glass cover plate is installed at the opening of the cavity receiver, and the concave surface of the spherical segment transparent glass cover plate is arranged inside the cavity receiver.

[0012] The new type of dish concentrator has a spherical diameter equal to the focal length of the system; the reflector and the receiver are installed on an azimuth tracking device, and a second tracking device is installed between the azimuth tracking device and the receiver to track the change of the sun's altitude; the tilt direction of the concentrator is adjusted manually, and the manual adjustment is performed 3-10 times per year, and the optimal design is 6 times; or the reflector and the receiver are installed on an equatorial tracking device, and a second tracking device is installed between the equatorial tracking device and the receiver, and the second tracking device tracks the change of the sun's declination angle; the tilt direction of the equatorial axis is adjusted manually, and the manual adjustment is performed 5-50 times per year, and the optimal design is 12 times.

[0013] All the spherical mirrors are closely spliced, and the entire spliced surface forms a continuous surface.

[0014] The initial value of the focal length of the dish solar heat collection system is specifically:

[0015] If the reference surface used is a parabolic surface, a spherical surface with a radius equal to the focal length, or a compact structure, the initial value of the edge angle of the solar heat collection system is set as , and the value range of is 30-50 degrees, and preferably 45 degrees; the focal length of the parabolic trough is calculated according to the clear aperture radius and the edge angle , and the calculation formula is:

[0016]

[0017] , wherein is the focal length of the parabolic trough, is the clear aperture radius, is the initial value of the edge angle;

[0018] If the reference surface is a spherical surface with a diameter equal to the focal length of the system, the initial value of the focal length is selected to be equal to the clear aperture diameter of the system.

[0019] The calculation formula of the radius is:

[0020]

[0021] , wherein is the radius, is the clear aperture radius, is the Gaussian distribution variance of the reflected sunlight, is the edge angle; , wherein the approximate calculation formula of

[0022] is:

[0023] ​​

[0024] wherein, is the solar disk Gaussian distribution variance, is the mirror slope error distribution variance; is the tracking error Gaussian distribution variance; is the system installation error Gaussian distribution variance; is the mirror material error Gaussian distribution variance.

[0025] The spherical mirror maximum radial width w is calculated as follows:

[0026] wherein, is the spherical mirror maximum radial width, is the clear aperture radius, is the reflected solar ray Gaussian distribution variance is the edge angle.

[0027] The mirror position and the radius of curvature start from the first mirror with the minimum edge angle;

[0028] When a compact structure is adopted:

[0029] The initial center coordinates are , the starting position edge angle is , and the equation is satisfied:

[0030]

[0031] wherein, R is the receiver radius, is the parabolic trough focal length, is the starting position edge angle, is the spherical mirror maximum radial width;

[0032] The edge angle is solved, and then the center coordinates are obtained; then the mirror radius of curvature can be calculated:

[0033]

[0034] wherein, is the mirror radius of curvature, is the parabolic trough focal length, is the starting position edge angle;

[0035] The other end position of the first mirror is calculated again ; then the second mirror center position is calculated in turn, which satisfies the equation group:

[0036]

[0037]

[0038]

[0039] wherein, is the edge angle of the second mirror, is the focal length of the parabolic trough, is the maximum radial width of the spherical mirror;

[0040] solving the equation set obtains the center coordinate and edge angle of the second mirror, and the radius of curvature; repeating the above steps, the center coordinate and edge angle of each mirror, and the radius of curvature are sequentially obtained;

[0041] When the center of each mirror is on the known reference surface:

[0042] the radius of the reference surface is , the first mirror center point position , then the first mirror satisfies the equation set:

[0043]

[0044]

[0045]

[0046] wherein, R is the receiver radius, is the edge angle of the second mirror, is the focal length of the parabolic trough, is the maximum radial width of the spherical mirror, is the radius of the reference surface;

[0047] solving the equation set obtains the center coordinate and edge angle of the first mirror, and the radius of curvature; then according to the center coordinate of the first mirror and the rotation angle, the position of the other end of the first mirror is obtained ;

[0048] the center position of the second mirror is sequentially calculated , satisfying the equation set:

[0049]

[0050]

[0051]

[0052] wherein, is the edge angle of the starting position, is the focal length of the parabolic trough, is the maximum radial width of the spherical mirror, is the radius of the reference surface;

[0053] Solving the equation set obtains the second mirror center coordinate and edge angle, and the curvature radius;

[0054] The above steps are repeated to sequentially calculate the center coordinates and edge angles of each mirror, and the curvature radius.

[0055] The utility model is improved on the basis of patents CN202320526509.4 and CN202310842421.8, and the invention points are as follows: the first invention point is that the curved surface composed of the center of the spliced mirror is the reference surface, which can be other rotating curved surfaces other than the rotating parabolic surface or spherical surface described in the previous patent, and the spherical center is not on the system symmetry axis required in the above two patent applications; meanwhile, the position of each spliced mirror center and the curvature radius are different from the design of the previous patent; the original scheme design only eliminates the meridional aberration, resulting in a large sagittal aberration; the new scheme simultaneously partially eliminates the meridional and sagittal aberrations, and reduces the spot radius; the second invention point is that the splicing centers are on the reference spherical surface, and the diameter is equal to the focal length of the system; when the system is installed on an azimuth tracking device or a polar axis tracking device, it is equivalent to using single-axis tracking to achieve point focusing for the first time in the field of solar energy concentrator, and the system performance is close to that of double-axis tracking, which is a major technical breakthrough in the field; the third invention point is to propose a compact splicing structure, and the splicing surface constitutes a continuous surface to eliminate the wind vibration problem caused by the gap between adjacent splicing surfaces, and the designed splicing system has high efficiency; the fourth invention point is to propose the design parameters of the above system, which replaces the current design parameters that need to be obtained through complex research.

[0056] Compared with the prior art, the utility model has the beneficial effects that:

[0057] The traditional disc system usually uses a rotating parabolic mirror as a primary mirror, which has high processing difficulty, high cost and large error, while the utility model uses a plurality of spherical mirrors with fan-shaped light transmitting surfaces to splice to form a mirror, which greatly reduces the processing difficulty, improves the precision, and reduces the cost. Compared with the scheme of using small-area planar mirrors to splice, which can reduce the difficulty but greatly reduces the condensing multiple, and the case of using a plurality of spherical mirrors to splice and constructing a system with aspherical mirrors, which leads to large aberration and high processing cost, the utility model has obvious advantages.

[0058] The curvature radius of the spherical mirror is further optimized, and the original is changed to equal, and the research on light tracing shows that the aberration is reduced by about 45%. At the same time, the new scheme not only can eliminate part of the meridional aberration, but also can reduce the sagittal aberration, effectively reduce the spot radius, significantly improve the condensing effect, and further improve the optical efficiency of the system.

[0059] By optimizing the curvature radius of the sector spherical mirror, the spherical aberration is further reduced, so that the mirror of the dish system composed of the sub-mirror can achieve better light condensing effect and improve the overall performance of the system.

[0060] In the field of solar light condensing collector, the structure with the splicing center on the reference sphere with the diameter equal to the focal length of the system is installed on an azimuth tracking device or a polar axis tracking device to realize single-axis tracking and point focusing, and the system performance is close to that of double-axis tracking.

[0061] A complete and systematic design parameter is given, which covers specific steps for determining key parameters such as clear aperture radius, focal length, receiver radius, mirror width, mirror position and curvature radius, and a system design program, a ray tracing program and a design parameter optimization program are also established. Through the design parameter, the optimized design parameters under different conditions can be calculated conveniently and quickly with the annual average light and heat efficiency as the optimization target, which replaces the previous complex research process and reduces the design difficulty and calculation amount.

[0062] The calculation method of the receiver radius is determined through research, and when the reflected light is intercepted within a 3σ angle range, the system can obtain the closest energy, effectively balancing the relationship between the intercepted energy and the lost energy of the receiver, reducing the energy loss and improving the energy utilization rate. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is a side view of the spherical surface spliced dish system;

[0064] Figure 2 is a ring-shaped spherical mirror composed of sector spherical mirrors of the spherical surface spliced dish system;

[0065] Figure 3 is an outline of the sector spherical mirror;

[0066] Figure 4 is a change relationship between the receiver interception rate and the receiver opening radius of the new dish system using the equatorial tracking;

[0067] Figure 5 is a performance table of the new dish condenser + tracking system at a latitude of 40 degrees in the optimization design;

[0068] Figure 6 is an aberration comparison of two spherical mirror splicing modes;

[0069] In the figure: 1, mirror, 2, spherical mirror, 3, receiver, 4, transparent glass cover plate, 5, spherical mirror. DETAILED DESCRIPTION

[0070] The technical scheme in the embodiments of the utility model will be described completely in combination with the drawings in the embodiments of the utility model.

[0071] As shown in Figures 1-6 ,

[0072] A new type of dish concentrator, comprising a reflector and a receiver, characterized in that the reflector is composed of a plurality of fan-shaped spherical mirrors, the central light of the sun is reflected to a common focus by the spherical mirrors, the receiver is a flat plate receiver or a cavity receiver, and the receiver is installed at the common focus, the distance from the center of the fan-shaped spherical mirror to the common focus is set to , and the radius of curvature of the spherical mirror is set to , satisfying .

[0073] The reference surface composed of the centers of all spherical mirrors is a rotationally symmetric surface, which can be a plane, a spherical surface, a rotationally parabolic surface, an ellipsoidal surface, or a hyperboloidal surface or other rotationally curved surface.

[0074] The reflector and the receiver are installed above a two-axis tracking device, and when the cavity receiver is used, a spherical segment transparent glass cover plate is installed at the opening of the cavity receiver, and the concave surface of the spherical segment transparent glass cover plate is inside the cavity receiver.

[0075] The reference spherical diameter of the new type of dish concentrator is equal to the focal length of the system; the reflector and the receiver are installed on an azimuth tracking device, and a second tracking device is installed between the azimuth tracking device and the receiver to track the change in the altitude of the sun; the inclination direction of the concentrator is manually adjusted, and the manual adjustment is 3-10 times a year, and the optimal design is 6 times; or the reflector and the receiver are installed on an equatorial tracking device, and a second tracking device is installed between the equatorial tracking device and the receiver, and the second tracking device tracks the change in the declination angle of the sun; the inclination direction of the equatorial axis is manually adjusted, and the manual adjustment is 5-50 times a year, and the optimal design is 12 times.

[0076] All the spherical mirrors are closely spliced, and the entire spliced surface forms a continuous surface.

[0077] The initial value of the focal length design of the dish solar energy collection system is specifically:

[0078] If the reference surface is a parabolic surface, a spherical surface with a radius equal to the focal length, or a compact structure, the initial value of the edge angle design of the solar energy collection system is set to , and the value range is 30-50 degrees, preferably 45 degrees; the parabolic trough focal length is calculated according to the light radius and the edge angle , and the calculation formula is:

[0079]

[0080] wherein, focal length of parabolic trough, optical diameter, design initial value of edge angle;

[0081] If the reference surface is a spherical surface with diameter equal to the focal length of the system, the initial value of the focal length is selected to be equal to the optical diameter of the system.

[0082] The radius, The calculation formula is:

[0083]

[0084] wherein, is radius, optical diameter, is the variance of the Gaussian distribution of reflected sunlight, is the edge angle;

[0085] The approximate calculation formula of σ is:

[0086]

[0087] wherein, is the variance of the Gaussian distribution of the sun, is the variance of the slope error distribution of the reflector; is the variance of the tracking error Gaussian distribution; is the variance of the system installation error Gaussian distribution; is the variance of the reflector material error Gaussian distribution.

[0088] The calculation formula of the maximum radial width w of the spherical reflector is as follows:

[0089] wherein, is the maximum radial width of the spherical reflector, optical diameter, is the variance of the Gaussian distribution of reflected sunlight is the edge angle.

[0090] The starting position of the reflector position and the radius of curvature is the first reflector with the minimum edge angle;

[0091] When a compact structure is adopted:

[0092] The initial center coordinates are , the starting position edge angle is , and the equation is satisfied:

[0093]

[0094] Wherein, R is receiver radius, is parabolic trough focal length, is starting position edge angle, is spherical mirror maximum radial width;

[0095] Solving the edge angle , and then the center coordinates can be calculated mirror radius of curvature :

[0096]

[0097] Wherein, is mirror radius of curvature, is parabolic trough focal length, is starting position edge angle;

[0098] The other end of the first mirror position is calculated; then the second mirror center position , which satisfies the equation group:

[0099]

[0100]

[0101]

[0102] Wherein, is the second mirror edge angle, is parabolic trough focal length, is spherical mirror maximum radial width;

[0103] Solving the equation group to get the second mirror center coordinates and edge angle, and the radius of curvature; repeat the above steps, in turn, the center coordinates of each mirror and edge angle, and the radius of curvature are obtained;

[0104] When each mirror center is on the known reference surface:

[0105] The reference surface radius is , the first mirror center point position , then the first mirror satisfies the equation group:

[0106]

[0107]

[0108]

[0109] Wherein, R is receiver radius, is the second mirror edge angle, f is the focal length of the parabolic trough, r is the maximum radial width of the spherical mirror, R is the radius of the reference surface;

[0110] Solving the equation set obtains the first mirror center coordinate and edge angle, and the curvature radius; and according to the first mirror center coordinate and the rotation angle, the position of the other end of the first mirror is obtained ;

[0111] The center position of the second mirror is calculated in sequence , satisfying the equation set:

[0112]

[0113]

[0114]

[0115] wherein, is the edge angle of the starting position, f is the focal length of the parabolic trough, r is the maximum radial width of the spherical mirror, R is the radius of the reference surface;

[0116] Solving the equation set obtains the first mirror center coordinate and edge angle, and the curvature radius; and according to the first mirror center coordinate and the rotation angle, the position of the other end of the first mirror is obtained

[0117] The center position of the second mirror is calculated in sequence

[0118] The following takes a new type of dish system composed of spherical mirrors with a clear radius R0=6.0 meters as an example to give the main design parameters, and the physical property data used includes:

[0119] The spherical mirror uses a glass back reflector with a reflectivity of 0.93, and the glass cover has a transmittance of 0.96 and an absorptivity of 0.96. In addition, the performance loss caused by pollution is 5%, and the average working temperature is 56°C. According to test data of the U.S. Solar Receiver No. 2, the heat loss when the glass cover is added is 6.036 kW / m2, and the heat loss when the glass cover is not added is 23.16 kW / m2. The atmospheric transparency is 0.75, and the direct normal irradiance resource is simulated using the clear day model at a latitude of 40 degrees. Three tracking modes are calculated for different optical designs, including azimuth tracking, earth axis tracking, and manually tracking the solar declination angle by adjusting the earth axis inclination once a month. The traditional rotating parabolic dish system with the same physical data is used for comparison. The annual average solar periphery rate calculated using the clear day model is 0.08, the average DNI is 800 W / m2, the parabolic dish slope error is 2.5 mrad, the spherical slope error is 1 mrad, and other errors are 1 mrad.

[0120] Since the aberration of off-axis focusing is related to the incident angle, the larger the incident angle, the larger the aberration, and the lower the concentration ratio. The key to a good system is to control the incident angle. For azimuth tracking, the reference spherical diameter is equal to the focal length in the spliced dish system, and at a latitude of 40 degrees, the maximum solar elevation angle is 73.5 degrees. If the minimum elevation angle for starting work is 15 degrees, the mirror is installed on the azimuth tracking device with an inclination of 45.75 degrees, which can ensure that the incident angle changes within 29.25 degrees. For earth axis tracking, if the inclination is not adjusted, the inclination should be fixed to equal the local latitude of 40 degrees, and the incident angle change is the solar declination angle change, so that it does not exceed 23.5 degrees. Since the higher the latitude, the larger the required main mirror inclination when using earth axis tracking, the structural requirements also increase accordingly. This shows that using a fixed spherical mirror and an earth axis tracking scheme, the structural requirements and costs in low latitude areas will be significantly lower than in high latitude areas, and it is more suitable for use in low latitude areas.

[0121] If the tracking axis inclination is adjusted periodically to track the change in solar declination angle, for example, the tracking axis inclination is adjusted once a month on average to track the change in solar declination angle, the maximum incident angle will be less than 47 / 12<4 degrees. In addition to non-normal incidence, it can also concentrate light, and through the receiver tracking device, its performance is close to that of normal incidence. The preliminary design calculation shows that the radial light passing width of the spherical heliostat is 0.6 meters, and the system light passing width is 6 meters. The following are the optimization results of various designs.

[0122] See Figure 5The performance table of the new dish concentrator + tracking system is optimized at latitude 40 degrees. The first six concentrators are all reference spherical diameters equal to the system focal length. The dish refers to a rotating parabolic dish, and the compact dish refers to a continuous surface formed by splicing. The same diameter dish refers to the splicing reference spherical radius equal to the system focal length. The slope error of the mirror of the dish system listed in the table is 2.5 mrad, which is the most likely mass-produced system used as a comparison standard. As a comparison, the slope error of the dish system is 1 mrad, which has the best performance, but is difficult to manufacture. However, the performance difference between the other two-axis tracking spherical mirror splicing dish system design scheme is small.

[0123] From the optimization results, single-axis tracking, including the earth axis tracking and azimuth tracking, if fixed installation, the system performance is much lower than the dish, among which the system performance of the receiver with transparent glass cover is better, and the optical-thermal efficiency is close to 65%; the efficiency of the receiver without transparent cover is only 56.2 to 57.6%. The concentration ratio is only between 100 and 300. The receiver without cover has large heat loss, and the optimized receiver has a small radius to reduce heat loss, and the interception rate is low, only 88% to 89%, but it will not produce the efficiency reduction caused by the absorption of the transparent cover, thereby offsetting part of the impact. However, the heat loss of the receiver with transparent cover is small, and a receiver with a larger radius can be used, and the interception rate increases by 8%, making the performance significantly better than the receiver without cover. However, when the incident angle is large, the aberration of the mirror is large, and the concentration ratio is low, only between the point focusing and line focusing system concentration ratio. But this system only needs to track the azimuth, and the single-axis tracking system is used instead of the two-axis tracking system, which realizes point focusing, thereby greatly reducing the system complexity, increasing the reliability, and reducing the cost.

[0124] Installing a two-way V-shaped groove concentrator or a conical concentrator on the receiver can improve the concentration ratio, reduce heat loss, and increase efficiency, which can improve the efficiency by about 2%; another improvement measure is to adjust the tilt angle of the system regularly. For the fixed installation of the spherical splicing system of the azimuth tracking, the maximum incident angle will change every season. If four different tilt angles are selected in a year, one tilt angle can be selected in each season to maximize the average cosine factor and efficiency of that season, which can improve the efficiency by about 1%.

[0125] If the use of the axis of the earth tracking plus 12 times a year tracking tilt adjustment, tracking the sun declination angle changes, when the incidence angle is less than 4 degrees, good light effect, focal area is small, so you can use a very small opening diameter receiver, light concentration ratio reaches more than 1000, instead of the performance of the receiver cover is better, because the high light concentration ratio, the efficiency loss caused by heat loss is small, and the increase of the transparent cover, will bring 4% loss, so as to affect more. The width of the annular spherical mirror used in the optimization calculation is 0.6 meters, which basically eliminates the spherical aberration caused by the use of spherical mirror, so as to ensure the system performance. Because of the use of spherical mirror, plus the use of width 0.6 meters, eliminate aberration, optical error is small, good light effect, its light and heat efficiency is only 0.29% lower than that of traditional rotating parabolic dish system. Its energy loss, in addition to the influence of physical properties, is the solar energy resources that are not fully utilized because the system does not start working when the solar altitude angle is lower than 15 degrees. Due to the high light concentration ratio, the efficiency reduction caused by the heat loss of the receiver is very small.

[0126] Reference Figure 6 The difference between the annular spherical mirror splicing scheme used in the foregoing patents CN202320526509.4 and CN202310842421.8 and the fan-shaped spherical mirror scheme used in the technical scheme of the present patent application is the aberration; the spherical center of the annular spherical mirror used in the foregoing patents is on the system rotation symmetry axis; while the fan-shaped spherical mirror used in the present patent is a rotating fan-shaped spherical mirror, which makes the center of the spherical mirror reflect the central light of the sun to the focal point, similar to the working principle of the heliostat, which is called the heliostat scheme, and the spherical center is not on the system rotation symmetry axis. The aberration of this scheme is smaller, so the performance is better.

[0127] In summary, although the fixed mirror system can be fixedly installed, and the receiver can be installed with bidirectional tracking to intercept the focused light. But this kind of fixedly installed system has a very low cosine factor and a small efficiency, which is not worth using. We propose to install it on the earth axis tracking device, and also adjust the tilt angle once a month to track the other direction change of the sun, which has a performance close to that of the dish system, which is equivalent to realizing the performance of the double-axis tracking dish system with single-axis tracking. This greatly reduces the tracking requirements of the system, and thus significantly reduces the cost; plus the use of spherical mirror instead of rotating parabolic reflector, further reduces the cost and improves the performance. Therefore, the new spherical mirror system proposed in this paper plus the earth axis tracking has obvious advantages in cost and performance compared with the traditional double-direction tracking dish system, so as to replace the dish system and become a new generation of light concentration collector with high efficiency and low cost.

[0128] The novel disc concentrator system under the condition of using the cavity without cover and the compact mode has the highest system efficiency, is only 0.13% lower than that of an ideal parabolic disc system under the same design condition, and is 1.58% higher than that of an actual parabolic disc system. This is equivalent to that the performance of the rotating parabolic surface under the same condition is realized by splicing the spherical mirrors, and also indicates that the optimization design eliminates the aberration caused by the spherical mirror.

Claims

1. A novel dish concentrator comprising a mirror and a receiver, characterized in that, The mirror is composed of a plurality of fan-shaped spherical mirrors with light passing surface, the central light of the sun is reflected to a common focus by the spherical mirrors, the receiver is a flat plate receiver or a cavity receiver, and is installed on the common focus, the distance from the center of the fan-shaped spherical mirror to the common focus is set as , the radius of curvature of the spherical mirror is set as , and satisfies .

2. The new type of dish concentrator according to claim 1, characterized in that, The reference surface composed of all the centers of the spherical mirrors is a rotationally symmetric surface, which can be a plane, a spherical surface, a rotationally parabolic surface, an ellipsoidal surface or a hyperboloidal surface.

3. A novel dish type concentrator according to claim 1, characterized in that, The reflector and the receiver are mounted above a two-axis tracking device, and when the receiver uses a cavity receiver, a spherical segment transparent glass cover plate is mounted at the opening of the cavity receiver, with the concave surface of the spherical segment transparent glass cover plate being inside the cavity receiver.

4. A novel dish type concentrator according to claim 1, characterized in that, The new dish-type concentrator has a reference spherical surface with a diameter equal to the focal length of the system; the reflector and the receiver are mounted on an azimuth tracking device, and a second tracking device is mounted between the azimuth tracking device and the receiver, for tracking the change in the solar altitude angle; Or the reflector and the receiver are mounted on an altitude tracking device, and a second tracking device is mounted between the altitude tracking device and the receiver, for tracking the change in the solar declination angle.

5. A novel dish type concentrator according to claim 1, characterized in that, All the spherical mirrors are closely spliced, and the entire spliced surface constitutes a continuous surface.

6. A novel dish concentrator as claimed in claim 1, wherein, The initial value of the focal length of the dish-type solar energy collection system is designed as follows: If the reference surface used is a parabola, a sphere with a radius equal to the focal length, or a compact structure, then set the initial design value for the edge angle of the solar thermal collector system. The The value range is 30-50 degrees; based on the light transmission radius. and edge corner Calculate the focal length of the parabolic trough The calculation formula is: wherein, is the focal length of the parabolic trough, is the clear aperture, is the initial value for the edge angle design; If the reference surface is a spherical surface with a diameter equal to the focal length of the system, the initial value of the focal length is selected as equal to the clear aperture diameter of the system.

7. A novel dish type concentrator according to claim 1, characterized in that, The radius The calculation formula is: wherein, is radius, is the clear aperture, is the variance of the reflected sunlight Gaussian distribution, is the edge angle. The approximate calculation formula of σ is as follows: wherein, is the solar photosphere Gaussian distribution variance, is the mirror slope error distribution variance; is the tracking error Gaussian distribution variance; is the system installation error Gaussian distribution variance; is the mirror material error Gaussian distribution variance.

8. A novel dish type concentrator according to claim 1, characterized in that, The formula for calculating the maximum radial width w of the spherical mirror is as follows: wherein, is the maximum radial width of the spherical mirror, is the clear aperture, is the Gaussian distribution variance of the reflected solar rays is the edge angle.

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