CN220305557U - Spherical disc type condenser - Google Patents
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Abstract
The utility model discloses a spherical disc-type condenser, which comprises a reflecting mirror and a receiver, wherein the reflecting mirror is formed by splicing a plurality of annular spherical mirrors, circles formed by transverse intermediate points of any annular spherical mirror are all on the same paraboloid of revolution, and the receiver is a flat receiver or a cavity receiver and is arranged on the focus of the paraboloid of revolution. The utility model provides a disc-type system reflector formed by splicing spherical reflectors as sub-reflectors, wherein each sub-reflector is a part of a spherical surface, and by controlling the width of the annular spherical reflector and designing a proper spherical radius, spherical aberration can be well eliminated, coma and astigmatism are avoided, a good light condensing effect is obtained, the system efficiency is improved by 4.25%, and the processing difficulty and cost are reduced.
Description
Technical Field
The utility model relates to the technical field of light and heat utilization of concentrating solar energy, in particular to a disc-type condenser.
Background
The concentrating solar heat utilization is to focus a large amount of low-density solar energy on a smaller area by using a concentrating technology, so that high-density solar energy is formed, high-temperature heat energy can be generated, and the concentrating solar heat utilization is used for solar heat power generation and is the heat power generation technology which is hopeful to replace a coal-fired power plant. The main concentrating solar technologies at present are tower, trough, linear fresnel and dish concentrating solar technologies.
In general, dish-type solar light-gathering technology uses a rotating parabolic mirror as a main mirror, uses a bidirectional tracking device, makes incident sunlight always enter the dish-type mirror at an incident angle of about 0 degrees, focuses the sunlight on a focus by the dish-type mirror, and uses a receiver or directly heats working medium to drive an engine mounted on the focus to generate power. The cosine factor of the method is maximum, the efficiency is highest, and the method is one of the most promising concentrating solar technologies.
However, in general, a dish system uses a rotating parabolic mirror as a main mirror, so that the processing difficulty of the rotating parabolic mirror is high, the cost is high, and the error is large, thereby reducing the performance of the system. The simplest solution is to splice small area mirrors to form a dish system mirror, which was studied in a doctor's paper, e.g. in the university of mesoscopy Wang Yunfeng, but the condensing magnification is greatly reduced and the performance is much worse than in a paraboloid dish system. Secondly, a plurality of spherical mirrors are spliced to form a reflecting mirror, a rotating paraboloid reflecting mirror is simulated, as in patent CN201220201616.1 and the optimization article published in apply Science in 2022, square spherical mirrors are used, the reflecting mirrors are spliced to form the reflecting mirror, the processing difficulty and cost of the reflecting mirror can be reduced, regular hexagons and regular triangle spherical mirrors are used in the literature, but spherical aberration including spherical aberration, meridian and sagittal aberration are introduced, and the system performance is still obviously reduced. The 3 rd solution is to use a spherical mirror as a primary mirror, which has become one of the main options of many giant telescopes in the field of astronomical telescopes, so that the processing difficulty and processing cost of the primary mirror can be greatly reduced, but a plurality of secondary mirrors are often required to correct spherical aberration, coma aberration and other aberrations, so that the system has a complex structure, the manufacturing difficulty and cost are increased, and the system is difficult to apply to the solar field. The patent CN200610041392.1 uses a spherical mirror instead of a paraboloid of revolution, without aberration correction, uses a tube receiver, and has a length equal to half of the spherical radius, i.e. the light condensing multiple and performance of the spherical mirror are greatly reduced. CN201610278112.2 and CN201610278111.8 use multiple aspherical mirrors to construct an off-axis disc system, which increases the processing difficulty and cost.
The use of double mirrors and multiple mirrors to construct a telescope is a common method in astronomy, in the solar field, the multiple mirror system is complex, the technical implementation is difficult and not very feasible, but currently, a double mirror system designed by using a double mirror scheme, for example, a double mirror system designed by a high-power solar collecting mirror based on Cassegrain structure (China optical, 2012, vol5, no4) published by Pan Jikun and the like, a receiver uses a photovoltaic cell, uses a rotating parabolic mirror as a primary mirror and a rotating hyperboloid as a secondary mirror, only spherical aberration is eliminated, the theoretical collecting ratio is only 550 times, the processing difficulty is high, the actual collecting ratio is 500 times, and the performance is lower than that of a traditional disc system.
One of the solutions proposed recently, as described in patent 2023100678201, is to splice ellipsoidal mirrors to form a main mirror, although the aberrations of the sub mirrors, including spherical aberration and astigmatism, are eliminated, the performance is maintained, the processing difficulty is reduced, the actual performance is increased, but the processing difficulty is still higher, and the processing precision is not higher than that of the spherical mirrors.
Disclosure of Invention
The utility model aims to overcome the defects of high processing difficulty, low precision and low system performance in the prior art and provides a spherical dish-type condenser.
The utility model is realized by the following technical scheme:
the spherical disc type condenser comprises a reflecting mirror and a receiver, wherein the reflecting mirror is formed by splicing a plurality of annular spherical mirrors, circles formed by transverse middle points of any annular spherical mirror are all on the same paraboloid of revolution, and the receiver is a flat receiver or a cavity receiver and is arranged on the focus of the paraboloid of revolution. The annular spherical surface is used to replace the corresponding annular paraboloid of revolution, and the light reflected by the annular spherical mirror has a common focus due to the smaller light transmission width of the annular spherical mirror, and the focal spot radius of the annular spherical mirror is smaller although the annular spherical mirror is a certain distance away from the focus of the whole spherical mirror, so that most of spherical aberration is eliminated. By adjusting the spherical position and the spherical radius, the focus of the annular spherical reflector is also on the focus of the paraboloid of revolution, thereby eliminating spherical aberration.
If the distance between any point on the circumference formed by the transverse middle points of the annular spherical mirror and the main axis of the paraboloid of revolution is d i The edge angle on the paraboloid of revolution isThe spherical radius of the annular spherical mirror is r i Then->
The goal of concentrating solar energy system optimization is to obtain the most thermal energy. Increasing the receiver radius can increase the interception rate so that the absorber absorbs more energy, but the receiver operates at high temperature, the lost energy is proportional to the receiver opening area, thus increasing the lost energy. Our studies have shown that the energy obtained is near maximum when the reflected light is intercepted for all distributions in the 3 sigma angular range. Further increasing the radius of the receiver, although the range of the interception opening angle can be increased, the intercepted energy is little increased, and the lost heat energy is increased more, so that the loss of the heat energy is not reimbursed, therefore, one of the conclusions is that the preliminary design is that the interception opening angle is smaller than or equal to the 3 sigma range and the sunlight can be reflected, and the radius r of the disc-type system receiver c Can be calculated as follows:
wherein σ is the reflected sunVariance of Gaussian distribution of light intensity, R 0 Is the light passing radius of the disc-type concentrating solar heat collecting system,the edge angle of the dish-type concentrating solar heat collection system is set; the reflected solar light intensity gaussian distribution variance sigma is calculated as:
σ sun is the Gaussian distribution variance sigma of solar light sphere slopex Is the mirror slope error distribution variance; sigma (sigma) tracking Is the tracking error gaussian distribution variance; sigma (sigma) disp The system installation error Gaussian distribution variance; sigma (sigma) specular Is the Gaussian distribution variance of the reflector material error, is usually small and can be ignored; referring to the measured data provided by the groove system research report Optical analysis and optimization of line focus solar collectors issued by Bendt et al, the variance sigma of the distribution of solar spheres can be taken sun 4.1mrad, sigma slope Is the slope error distribution variance of the reflector, and when a spherical mirror is used, 1.0mrad is taken; sigma (sigma) tracking Taking 1.0mrad from the tracking error Gaussian distribution variance; sigma (sigma) disp Taking 1mrad from the Gaussian distribution variance of the system installation error; sigma (sigma) specular The error Gaussian distribution variance of the reflector material is usually small and negligible; sigma=4.776 mrad was calculated. The results can be used as preliminary design values for optimization.
The light transmission width of any annular spherical mirror should not exceed the upper limit calculated by the following method:
if the maximum value of the angle between the connecting line from any point of the annular spherical mirror to the focus and the symmetrical axis of the paraboloid of revolution is phi, the upper edge angle of the ring corresponding to the transverse intermediate point
The upper limit of the annular spherical mirror light transmission width w is calculated as follows:
according to the design of the formula, the aberration caused by the spherical mirror can be eliminated, so that the defects caused by using the spherical mirror are eliminated, and meanwhile, the advantages of easiness in processing and small optical error of the spherical mirror can be utilized.
The annular spherical mirror is formed by splicing sector spherical mirrors, and the appearance and the spherical radius of each sector spherical mirror forming the same annular spherical mirror are the same, so that the annular spherical mirror can be conveniently manufactured.
The edge angle range of the dish-type concentrating solar heat collection system is 35-50 degrees, and one value is selected from the edge angle range to start design calculation. Typically 45 degrees is used as the initial design value.
The disc-type concentrating solar heat collection system is arranged on the bidirectional tracking device.
When the cavity receiver is used by the receiver, the transparent glass cover plate with the spherical surface is arranged at the opening of the cavity receiver, and the concave surface of the transparent glass cover plate with the spherical surface is arranged in the cavity receiver.
The utility model has the advantages that: the utility model provides a disc-type system reflector formed by using spherical reflectors in a spliced manner as sub-reflectors, wherein each sub-reflector is a part of a spherical surface, spherical aberration is well eliminated by controlling the width of the annular spherical reflector, and coma and astigmatism are avoided, so that a good light condensing effect can be obtained, the system efficiency is improved, and the processing difficulty and cost are reduced.
Drawings
FIG. 1 is a side view of a sphere splice disc system;
FIG. 2 is a view of a circular spherical mirror formed by stitching spherical stitched disc-type system sector spherical mirrors;
FIG. 3 is a profile of a sector sphere mirror;
fig. 4 is an open face (focal plane) fluence distribution diagram of a novel disc system receiver.
Detailed Description
As shown in fig. 1-4, a spherical dish-type condenser comprises a reflecting mirror 1 and a receiver 3, wherein the reflecting mirror 1 is formed by splicing a plurality of annular spherical mirrors 2, circles formed by transverse intermediate points of any annular spherical mirror 2 are all on the same paraboloid of revolution, and the receiver 3 is a flat receiver or a cavity receiver and is arranged on the focus of the paraboloid of revolution.
If the distance between any point on the circumference formed by the transverse middle points of the annular spherical mirror and the main axis of the paraboloid of revolution is d i The edge angle on the paraboloid of revolution isThe spherical radius of the annular spherical mirror is r i Then->
Said receiver radius r c Calculated as follows:
where σ is the reflected solar light intensity Gaussian distribution variance, R 0 Is the light passing radius of the disc type concentrating solar heat collecting system,the edge angle of the dish-type concentrating solar heat collection system is set; the reflected solar light intensity gaussian distribution variance sigma is calculated as:
σ sun is the Gaussian distribution variance sigma of solar light sphere slopex Is the mirror slope error distribution variance; sigma (sigma) tracking Is the tracking error gaussian distribution variance; sigma (sigma) disp The system installation error Gaussian distribution variance; sigma (sigma) specular Is that the error of the reflector material is highThe variance of the gaussian distribution.
The upper limit of the light transmission width of any annular spherical mirror is calculated according to the following method:
if the maximum value of the clamping angle between the connecting line from any point of the annular spherical mirror to the focus and the symmetrical axis of the rotating paraboloid is phi i The upper edge angle of the ring corresponding to the transverse middle point
The upper limit of the annular spherical mirror light transmission width w is calculated as follows:
the annular spherical mirror is formed by splicing the sector spherical mirrors 5, and the appearance and the spherical radius of each sector spherical mirror forming the same annular spherical mirror are the same.
The edge angle range of the dish-type concentrating solar heat collection system is 35-50 degrees, and one value is selected from the edge angle range to start design calculation.
The disc-type concentrating solar heat collection system is arranged on the bidirectional tracking device.
When the cavity receiver is used, the transparent glass cover plate 4 with the spherical surface is arranged at the opening of the cavity receiver, and the concave surface of the transparent glass cover plate 4 with the spherical surface is arranged in the cavity receiver.
The design method of the utility model comprises the following specific steps:
firstly, determining the light transmission radius R of a disc-type concentrating solar heat collection system according to requirements 0 ；
Secondly, determining that the edge angle of the dish-type concentrating solar heat collection system is 45 degrees;
third step, determining focal lengthThe radius of the receiver is +.>
Step four, firstly, determining the width of the outermost annular spherical mirror, and calculating the edge angle of the center of the annular spherical mirror on the paraboloid of revolution according to the following formula
At this timeThe upper limit of the annular spherical mirror light transmission width w is calculated as follows:
thereby determining the light transmission width w of the annular spherical mirror, and then determining the distance d between any point on the center circle of the annular spherical mirror and the main shaft i Calculated as follows:
the spherical radius r of the annular spherical mirror i The calculation formula is as follows:
fifthly, calculating the maximum edge angle data of the second annular spherical mirror according to the fourth step, and sequentially determining the light transmission width parameters of the annular spherical mirrors according to the method;
and sixthly, simulating the performance of the computing system by using a ray tracing program, and if the result is not satisfied, adjusting the radius of the receiver or changing the edge angle of the system, and completing new design and performance calculation again according to the fourth to sixth sections.
The lower surface is spliced by annular spherical mirrors to form the light transmission radius R 0 For example, a disc system of 4.1 meters gives the main design parameters. As described above, the variance σ=4.776 mrad of the gaussian distribution of the reflected light intensity, with the cavity receiver, the system edge angle at the maximum condensing ratioAt 45 degrees, receiver radius rc=117.5 millimeters, and light collection ratio 1214. Focal length of systemThe light transmission width of the spherical reflecting mirror is 0.4 meter, and 10 annular spherical mirrors are used. In actual manufacturing, a plurality of sector spherical reflectors are spliced to form an annular spherical reflector, and the width of each sector spherical reflector can be flexibly about 0.5 meter. The cavity receiver is installed on the focus of the paraboloid of revolution, and the system is installed on the bidirectional tracking device, so that the disc type system capable of collecting solar energy can be formed. We have established a ray tracing procedure that calculates the focal plane fluence distribution as shown in fig. 4. The interception rate reaches 99.8 percent. If the same disc type system is constructed by adopting a rotating paraboloid, the light transmission radius is the same as the radius of the receiver, but the radial error of the paraboloid is 3mrad, the optical error is 7.4mrad, the interception rate is 95.1 percent, and the method is 4.7 percent lower than that of a spliced disc type system, and is complex to manufacture and high in cost. Therefore, the scheme not only improves the system efficiency, but also reduces the manufacturing cost.
The principle of the solar dish type condenser is similar to that of an astronomical reflection telescope, and the astronomical telescope mainly focuses fixed star light and planetary light with low light intensity, so that the target structure, namely the optical imaging system, is required to be perfectly reproduced, and the requirement is much higher than that of the solar condenser. Solar dish systems can then use non-imaging systems, with the main goal of high light concentration ratio, thus reducing heat loss and obtaining more thermal energy. The low-cost astronomical reflecting telescope mostly uses spherical reflecting mirror to replace parabolic reflecting mirror, which is simple in manufacturing process and low in manufacturing cost, but mostly uses long-focal-length system so as to eliminate spherical aberration of spherical reflecting mirror. In a disc solar energy system, a spherical mirror can be used instead of a parabolic mirror, and the main disadvantage is that spherical aberration can be eliminated by increasing the focal length, but the light spot radius is proportional to the focal length, so that the light concentration ratio is reduced and the heat loss is increased. The utility model provides a plurality of annular spherical mirrors to be spliced, and by using spherical mirrors with different radiuses, the width of the annular spherical mirrors is limited, so that the spherical aberration is eliminated, the defect that the spherical aberration exists when the spherical mirrors are used is overcome, and the advantages of easiness in manufacturing and lower optical error of the spherical mirrors are utilized. The practical requirement is to select proper annular spherical lens width, spherical radius and focal length and receiver radius according to the optical error of the collecting lens, the solar light intensity distribution parameter, the heat loss of the receiver and other system properties. The relation between the light concentration ratio and the spherical radius, the focal length and the radius of the receiver is determined according to the intercepted reflected light intensity distribution width, so that the optimal design parameters can be calculated and obtained, and the maximum net energy is obtained. The following is the analytical calculation method we set up:
see the 2013 article, optical analysis and optimization of parabolic dish solar concentrator with a cavity receiver (solar energy,2013,Vol 92,pp288-297), which considers that the incident energy is constant, our optimization objective may also be the maximum annual average net thermal efficiency η of the system, calculated as follows:
ρ is the specular reflectance, τ is the transmittance of the receiver plus transparent cover plate, 1.0 when no transparent cover plate is present, α is the receiver absorptivity, γ is the receiver interception, which can be calculated using a ray tracing program or estimated according to the method presented herein (see below); the last term of the expression is the reciprocal of the geometric light concentration ratio; q is the heat loss per unit area of the receiver (in W/m 2 ) Where ζ is the ratio of heat lost energy per unit receiver area to direct solar energy received by the unit area concentrator over a year, we refer to the coefficient of heat lost by the system, and we use a sunny model approximation to calculate the annual average ζ, such asThe following formula:
where the integral of g represents the total time of operation of solar altitude greater than 15 degrees in one year, the denominator is the total amount of direct solar energy resources per unit area in one year, and at a certain operating temperature, the heat loss q per unit area of the receiver can be approximated as a constant. For example, the total heat loss power of a WGA cavity receiver with an opening diameter of 0.14m is about 0.260kW at an operating temperature of 800 c, which varies slightly with the solar altitude, and about 2% at a maximum change of 60 degrees (FRASER 2008). In general, we can calculate the cavity receiver heat loss using the following formula (Siebers DL, kraabel JS Estimating convective energy losses from solar central receivers, sandia National Laboratories; 1984.):
wherein T is w Is the average temperature of the receiving surface, T a Is the ambient temperature, a is the cavity receiver opening area; here epsilon is the emissivity and sigma is the boltzmann constant = 5.67 x 10 -8 W/(m 2 K 4 )。
The annual average DNI can be calculated by adopting a sunny model or measured data to obtain the heat loss coefficient xi, so that the annual average net heat energy efficiency eta of the system under different design parameters can be calculated in a simulation manner heat And obtaining the optimal design parameters.
By adopting the cavity receiver, a transparent cover plate can be added at the opening to reduce heat loss, but solar energy entering the receiver can be reduced due to the fact that the transmittance is lower than 1. Generally, quartz glass is used in many cases, and has high temperature resistance and high transmittance, but the common quartz glass has low transmittance and sometimes cannot counteract heat loss, the main reason is that the sunlight is incident on the common quartz glass and has high reflectivity, the main measure for reducing the reflectivity is to add an anti-reflection film on the surface of the quartz glass, so that the surface reflection is reduced, the transmittance can be increased, and the document reports that the transmittance can be increased from 93% to 99%.
We have previously calculated the heat loss coefficient of a receiver-followed-by-Style engine, two typical cavity receivers operating at 800℃, one being a cavity receiver without a transparent cover plate, with heat loss of 16.26W/cm 2 The heat loss coefficient is 168.25; the other is a cavity receiver with a transparent cover plate, and the heat loss is 1.67W/cm 2 The heat loss coefficient was 18.177. The system can group a plurality of disc-type systems to respectively work at different temperatures, so that the heat loss can be further reduced, and the workload is increased by several times for the optimal design.
The system is equal to a disc-type system reflector formed by splicing a part of a plurality of spherical reflectors, and sun center rays are perpendicularly incident to each spherical reflector, so that coma and astigmatism are small and negligible. Spherical mirrors are used to bring in spherical aberration. The proposal adopted by the method is to use a ring-shaped spherical mirror to eliminate the spherical aberration by limiting the width of the reflecting mirror, and the method for eliminating the spherical aberration is discussed below. The spherical aberration refers to parallel light incident on a main axis of a parallel spherical mirror, a larger light spot is formed on a focal plane, and the light spot radius deltax is transverse spherical aberration, see (Su) Ke Torpedo et al, on page 175 of research and inspection of optical systems, and can be expressed by the following formula:
δ x ＝r*tan(ψ)*sin 2 (ψ/4)/cos(ψ/2)
r is the radius of the sphere of the spherical mirror, and ψ is the maximum intersection angle of the sphere mirror reflected light with the principal axis.
The spherical aberration does not exist in the rotating parabolic dish system, the receiver mainly intercepts scattered reflected light, but the spherical sub-mirrors are used for splicing to form the rotating parabolic dish system, the spherical aberration is necessarily generated, the spherical aberration is related to the spherical size according to the formula, since the ratio R0/r=sin (psi/2) of the spherical light-transmitting caliber R0 to the spherical radius R is larger according to the spherical aberration calculation formula,the greater the spherical aberration. Since r increases to increase the image spot radius, one mainly limits the light passing size of the reflector to eliminate spherical aberration, and our study shows that if σ is the variance of Gaussian distribution of reflected light intensity, at least the reflected light in the 3σ range should be completely intercepted to obtain the receiver radius r c The calculation should be as follows:
R 0 is the light passing radius of the disc type system,is the edge angle of the disc system, wherein the calculation formula of the reflected light intensity Gaussian distribution variance sigma is as follows:
referring to the measured data provided by the groove system research report Optical analysis and optimization of line focus solar collectors issued by Bendt et al, the variance sigma of the distribution of solar spheres can be taken sun 4.1mrad, sigma slope Is the slope error distribution variance of the reflector, and when a spherical mirror is used, 1.0mrad is taken; sigma (sigma) tracking Taking 1.0mrad from the tracking error Gaussian distribution variance; sigma (sigma) disp Taking 1mrad from the Gaussian distribution variance of the system installation error; sigma (sigma) specular The error Gaussian distribution variance of the reflector material is usually small and negligible; sigma=4.776 mrad was calculated.
When using spherical mirror splicing, the transverse spherical aberration delta x The radius of the intercepted reflection light spot is increased, and at the moment, the radius of the receiver is calculated as follows:
we eliminate the spherical aberration, i.e. to reduce the influence of the spherical aberration, for the presentOur research results suggest that when the spherical aberration delta is x ≤30％r c The effect is negligible, namely:
for a toroidal spherical mirror, the image spot radius or lateral spherical aberration can be calculated as follows:
the spherical radius of the annular spherical mirrorSubstituting the above formula to obtain:
can be solved by a numerical method to obtain the psi, if the width of the annular spherical mirror is w
Thereby obtaining the maximum width w required for eliminating the spherical aberration of the annular spherical mirror. The maximum width w may also be approximated using the following method:
since the spherical aberration increases rapidly with increasing ψ, we only need to estimate the maximum case of ψ, which is then equal to the system edge angleThen it can be approximated as follows:
the width w of the annular spherical mirror can be calculated according to the formula, and under the design requirement, the system can eliminate spherical aberration caused by the applicable spherical mirror, so that a good focusing effect is achieved.
The beneficial effects of using the cavity receiver are analyzed below.
The use of a cavity receiver is advantageous over a flat receiver because the cavity receiver has a high absorption rate and light is substantially absorbed by the receiver after entering the cavity, whereas the flat receiver reflects a portion of the intercepted solar light, typically about 5% to 10%, resulting in a lower absorption rate. This is a major benefit of using a cavity receiver.
In addition, referring to fig. 4, the dish-type paraboloid-of-revolution reflector has a very uneven distribution of energy flux density on the focal plane, and the focal plane has a high center energy flux density and a low edge density, so that the temperature distribution of the receiving surface arranged on the focal plane is uneven, resulting in larger heat loss, poorer thermal stability and easy burning of the receiving surface. The cavity receiver is used to change the distance between different positions and focus, so as to regulate the energy flow density of the receiving surface and maintain uniform cavity energy flow density distribution and temperature distribution.
The design method provided by the utility model can quickly and conveniently determine various optical design parameters of the annular spherical disc type system. How to select various design parameters of the system, including the system light transmission radius, focal length, edge angle, receiver radius, annular sub-mirror width, spherical radius, etc., often needs a large amount of simulation calculation to determine the system performance under different conditions, and comprehensively considers the influence of various factors, for example, the slot system research report Optical analysis and optimization of line focus solar collectors published by Bendt et al in the United states. The method has complex process and great workload, and an optimized design scheme is not necessarily obtained. According to the method, a light concentration ratio calculation formula is obtained according to a receiver size calculation formula provided by the inventor, so that the optimal edge angle and the receiver size can be determined, and each design parameter of the system is determined. In the aspect of the design of the spliced sub-mirrors, conditions and a calculation formula for eliminating spherical aberration are established, so that the width parameters of the annular spherical mirror are determined. The design method provided by the utility model has the advantages of simple calculation process and clear thought, can easily obtain reliable design, is superior to the design obtained by the traditional optical method, and can be optimized to obtain the optimal design on the basis.
After the primary design is optimized, the design parameters of the scheme provided for the practical system are that the main lens light transmission radius is 4.1 meters, the edge angle is 45 degrees, the receiver radius is 117.5 millimeters, and the geometric light concentration ratio is 1214.4 times. Using Gaussian reflected light intensity distribution, the variance was 4.776mrad, simulating the performance of the computing system, with an interception rate of 99.8%. Fig. 4 shows the calculated fluence distribution on the receiving surface. The net energy efficiency was 90.15%. In contrast to the use of a paraboloid of revolution, the slope error increases to 2 to 4mrad, calculated as an average of 3mrad, and when the same receiver and geometric concentration ratio is used, the interception rate decreases to 95.1%, 4.7% lower than the system presented herein, and the net energy efficiency decreases to 85.9% 4.25% lower than the system presented herein.
Claims (8)
1. A spherical dish-type condenser comprising a reflector and a receiver, characterized in that: the reflector is formed by splicing a plurality of annular spherical mirrors, circles formed by transverse intermediate points of any annular spherical mirror are all on the same paraboloid of revolution, and the receiver is a flat receiver or a cavity receiver and is arranged on the focus of the paraboloid of revolution.
2. A spherical dish-type condenser as claimed in claim 1, wherein: if the distance between any point on the circumference formed by the transverse middle points of the annular spherical mirror and the main axis of the paraboloid of revolution is d i The edge angle on the paraboloid of revolution isThe spherical radius of the annular spherical mirror is r i Then->
3. A spherical dish-type condenser as claimed in claim 2, wherein: said receiver radius r c Calculated as follows:
where σ is the reflected solar light intensity Gaussian distribution variance, R 0 Is the light passing radius of the disc-type concentrating solar heat collecting system,the edge angle of the dish-type concentrating solar heat collection system is set; the reflected solar light intensity gaussian distribution variance sigma is calculated as:
σ sun is the Gaussian distribution variance sigma of solar light sphere slopex Is the mirror slope error distribution variance; sigma (sigma) tracking Is the tracking error gaussian distribution variance; sigma (sigma) disp The system installation error Gaussian distribution variance; sigma (sigma) specular Is the gaussian distribution variance of the mirror material errors.
4. A spherical dish-type condenser as claimed in claim 3, wherein: the upper limit of the light transmission width of any annular spherical mirror is calculated according to the following method:
if the maximum value of the clamping angle between the connecting line from any point of the annular spherical mirror to the focus and the symmetrical axis of the rotating paraboloid is phi i The upper edge angle of the ring corresponding to the transverse middle point
The upper limit of the annular spherical mirror light transmission width w is calculated as follows:
5. a spherical dish-type condenser as claimed in any one of claims 1 to 4, wherein: the annular spherical mirror is formed by splicing sector spherical mirrors, and the appearance and the spherical radius of each sector spherical mirror forming the same annular spherical mirror are the same.
6. A spherical dish-type condenser as claimed in claim 3, wherein: the edge angle range of the dish-type concentrating solar heat collection system is 35-50 degrees, and one value is selected from the edge angle range to start design calculation.
7. A spherical dish-type condenser as claimed in claim 6, wherein: the disc-type concentrating solar heat collection system is arranged on the bidirectional tracking device.
8. A spherical dish-type condenser as claimed in claim 7, wherein: when the cavity receiver is used by the receiver, the transparent glass cover plate with the spherical surface is arranged at the opening of the cavity receiver, and the concave surface of the transparent glass cover plate with the spherical surface is arranged in the cavity receiver.
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