CN114912370B

CN114912370B - Building photovoltaic potential analysis available area calculation method

Info

Publication number: CN114912370B
Application number: CN202210661171.3A
Authority: CN
Inventors: 彭玲; 陈德跃; 王靖凯; 李玮超; 宋福龙; 陈晨
Original assignee: Aerospace Information Research Institute of CAS
Current assignee: Aerospace Information Research Institute of CAS
Priority date: 2022-06-13
Filing date: 2022-06-13
Publication date: 2023-08-22
Anticipated expiration: 2042-06-13
Also published as: CN114912370A

Abstract

The invention relates to a building photovoltaic potential analysis available area calculation method, which comprises the following steps: step 1, building vector information is obtained by utilizing multi-element space-time information, building roof area, side elevation area and height information are calculated according to geometric features of the building vector information, and building vector information attributes are written; step 2, calculating the shaded surface area between the buildings according to the building vector information, the height information and the solar radiation parameters, and further subtracting the shaded surface area from the total surface area to obtain the usable area of the building roof and the usable area of the side elevation; and 3, calculating the optimal inclination angle and the optimal installation distance of the photovoltaic equipment installed on the roof of the building by using the fixed installation type photovoltaic equipment, and obtaining the installed capacity and the photovoltaic potential of the photovoltaic equipment installed on the roof of the building by considering the shadow shielding area of the roof.

Description

Building photovoltaic potential analysis available area calculation method

Technical Field

The invention relates to the field of electric power, in particular to a building photovoltaic potential analysis available area calculation method.

Background

The chinese patent publication No. CN102163341B discloses a method for building a solar power plant model by shadow analysis, comprising the steps of: collecting topographic data, obstacle data and solar module data; drawing a shadow distribution map; establishing an initial model of the solar power station; and (5) shadow analysis calculation after model establishment. The method is mainly suitable for designing the photovoltaic power station based on the ground plane, calculates the shadow length by adopting an empirical formula of the distance between the photovoltaic arrays, and does not consider optimization of the distance between the photovoltaic arrays.

The Chinese patent document with publication number CN103559738A discloses a mountain photovoltaic power station arrangement method, which comprises the following steps: the Google earth software and ArcGIS software are applied to complete slope modeling, and a TIN topographic map is generated; simulating and calculating a TIN topographic map of the mountain area through sunlight analysis software; the mountain trend is fully supported, and the photovoltaic arrays are arranged along the mountain, so that the steel consumption and the occupied area of the bracket are reduced; and performing shadow outline polygon analysis on the TIN topographic map of the mountain area through sunlight analysis software to determine positioning points of the array. The invention relates to a method for arranging a mountain photovoltaic power station, but a sampling shadow length calculation formula adopted in the laying process of photovoltaic equipment does not consider optimizing the distance between photovoltaic arrays.

The Chinese patent document with publication number of CN104281741A discloses a multi-factor comprehensive calculation method for the inclination angle and array spacing cross feedback of a photovoltaic module, which comprises the following steps: initially calculating the inclination angle of the component; performing primary calculation on array spacing; optimizing array spacing; and optimizing the inclination angle of the assembly. Although the invention provides a comprehensive calculation method for reasonably determining the inclination angle of the assembly and the array spacing aiming at pursuing the maximum power generation benefit, the roof-type photovoltaic equipment is paved under the condition of not considering the limitation of a fixed site in the process.

The Chinese patent document with publication number of CN105760590A discloses a roof type photovoltaic array space optimization method based on shadow radiation analysis, wherein the real-time solar altitude and solar azimuth angle of an area where longitude and latitude coordinates are located are obtained by using the solar time angle and declination, the installation space of the photovoltaic array is obtained according to an empirical formula, the static investment of unit electric energy is calculated, then the installation space of the photovoltaic array is adjusted according to a certain step length according to factors such as shadow radiation analysis of the roof of the area, and the photovoltaic space at which the static investment of the unit electric energy reaches the minimum is calculated. The invention considers the shielding of the shadow on the roof of the building while calculating the power generation benefit, but does not consider the shielding of the shadow on the side elevation of the building, ignores the possibility of installing the photovoltaic equipment on the side elevation of the building, and does not influence the installation strategy of the photovoltaic equipment on different roof types such as flat roofs, pitched roofs and the like.

The Chinese patent document with publication number of CN114266984A discloses a method for calculating carbon reduction of photovoltaic reformable areas on roofs of buildings by using high-resolution remote sensing images. The patent utilizes the deep Lab neural network to extract the roof outline of the building from the high-resolution second-number remote sensing image, classifies roof types, calculates the usable area of roof photovoltaics, and finally calculates the installed capacity and the carbon reduction of the roof photovoltaics. However, this patent ignores the photovoltaic availability area of the building side facade and calculates the roof photovoltaic availability area based solely on empirical correction factors that, while taking into account the use and type of roof, do not accurately calculate the effect of ambient building shadow masking on the photovoltaic availability area of a particular roof in a real environment. Furthermore, in the step of calculating the installed capacity of the photovoltaic, the patent only assumes that the optimum installation inclination of the rooftop photovoltaic apparatus is known, and does not consider that the optimum installation inclination is affected and limited by the local solar radiation parameters, nor does it describe the method of calculating the optimum installation inclination.

Chinese patent publication No. CN113221355a discloses a method for arranging irregular roof photovoltaic panels of complex buildings. The patent aims at building roofs with complex shapes, firstly, a three-dimensional model of the building is built, an interference processing module is used for calculating the surface shadows of the building, and then, roof parts which are not affected by the shadows are segmented and arranged so as to achieve the aim of installing the maximum photovoltaic arrays. However, the three-dimensional model and the interference processing established by the patent have high computational complexity and long data acquisition and calculation flow, are only suitable for fine application facing the small-range scene of the park level, and are difficult to be used for the large-range photovoltaic potential analysis application scene of the provincial level aiming at the invention.

The above-mentioned patent does not take into account the shadows of the building in full or on the side facades of the building; or the shadow of the building is calculated by using software, and the calculation requirement of a large number of buildings cannot be met.

Shadows refer to dark areas of a scene that are not directly illuminated by a light source. Shadows reflect the spatial positional relationship between the sun and objects in the scene. The portion of the building covered by the shadow is not suitable for photovoltaic installation, and calculating the distribution of the building shadow is one of the important references for photovoltaic installation. In computer graphics, shadows can be divided into self shadows and cast shadows. Self-shadow refers to some surface that is blocked from light by the object itself. A projected shadow refers to a shadow that is formed by objects in the scene that are behind it that are not exposed to the surface of illumination due to the occlusion of the objects. The projected shadow can be divided into a penumbra and a penumbra. Penumbra refers to the well-defined portion of the drop shadow that is in the middle full black, and penumbra refers to the area of half-brightness and half-darkness surrounding the penumbra.

The shadow generation algorithm is mature, the general process is that the view point is placed at the position of the light source, the light direction is taken as the observation direction, and the hidden surface of the object under the illumination model can be distinguished by implementing the blanking algorithm on the object corresponding to the illumination model. Therefore, building self-shading algorithms are not discussed herein, and penumbra calculation is relatively complex with respect to home shadows. The present invention only discusses the generation algorithm of the home shadows of the building. The shadows of the building in the following description of the invention are all the shadows of the building.

The shadow analysis algorithm currently in common use for the home shadows of a building is as follows:

(1) The image domain polyhedral method comprises the following steps:

the image area is the area of the scene space where the light is blocked by the object outline polygon, that is, the area formed by the object outline polygon performing a translational scan along the light projection direction. Since the object obscures the light source, a shadow is formed behind the object. The image field polyhedron is a spatial boolean intersection of a view rectangular pyramid and an image field, so any scene surface located in the image field polyhedron is a shadow surface. Therefore, it is only necessary to determine whether or not a certain point is located in a shadow, and whether or not the store is located in a shadow polyhedron.

(2) Z buffer method:

shadows are areas that are invisible to the light source but visible to the viewpoint, so the process of generating shadows amounts to two blanks, one for blanking the light source and one for the viewpoint. The Z-buffer method is based on this principle and comprises the following specific steps:

1) The scene is blanked in the direction of the light source using a Z-buffer blanking algorithm, all of the scene being transformed to the light source coordinate system, at which time the Z-buffer stores depth values for scene points closest to the light source that are visible to the light source.

2) And calculating the picture according to the line-of-sight direction by utilizing a Z buffer zone blanking algorithm, transforming the visible point on the curved surface corresponding to each pixel to a light source coordinate system, and comparing the transformed depth value with the depth value stored in the shadow buffer.

3) If the depth value in the Z-buffer is small, it means that the point is not closest to the light source, but is invisible from the direction of the light source, i.e. is in the shadow.

(3) Ray tracing generation algorithm:

it is determined whether a point in the scene is in the shadow of a light source, from which point a probe ray is emitted to the light source. If the detection light is blocked, the point is located inside the shadow, otherwise the point is located outside the shadow.

The three shadow analysis algorithms are mainly used for the conditions of multiple light sources and complex objects, and have high calculation complexity. The photovoltaic potential analysis is faced with the situation that sunlight irradiates a building group to generate shadow shielding on the surface of a building, the light source is single, the shape of the building is regular, and a large advantage space is reserved for the algorithm provided by the invention.

According to the regulations of building fire-fighting design specifications and civil building design unified standards, the high-rise building is not lower than 24 meters, the super high-rise building is not lower than 100 meters, the distance between the multi-layer buildings is not lower than 6 meters, the distance between the multi-layer buildings and the high-rise building is not lower than 9 meters, and the minimum distance between the high-rise buildings is 13 meters. From the above provisions, if the space between the high-rise buildings is designed according to the minimum standard, the sun irradiates the high-rise building obliquely at the morning and afternoon, the shadow of the former building can be used for shielding the surface of the latter building, so that the shielded surface cannot be directly irradiated by the sun, and meanwhile, most shadow analysis algorithms at present mainly consider the complex situations of point light sources and multiple light sources to calculate the propagation of light rays in the three-dimensional space, so that the shadow calculation complexity of the former prior art scheme generated by the regular building under the action of parallel light is too high, and the problem of low efficiency exists when the prior art scheme faces to large-area calculation application scenes such as province areas. Under the background, the invention provides a method for calculating shadow distribution and photovoltaic usable area of a building roof and each elevation aiming at the problems existing in the prior art and facing to large-area application scenes such as provincial areas, and the method supports accurate calculation of photovoltaic potential of the building.

Disclosure of Invention

In order to solve the technical problems, the invention utilizes high-resolution remote sensing images (such as high-resolution satellites and unmanned airborne laser radars) to extract building vector information and height information in a large-area building group, designs an automatic algorithm for calculating the shadow distribution of the surface of a building for photovoltaic potential analysis, and analyzes each building by using the algorithm according to the vector information and the height information of the building group to obtain an effective available area region comprising a roof, a side elevation and other mountable photovoltaic equipment.

The technical scheme of the invention is as follows: a building photovoltaic potential analysis available area calculation method comprises the following steps:

step 1, building vector information is obtained by utilizing multi-element space-time information, the roof area, the side elevation area and the height of a building are calculated according to the geometric characteristics of the building vector information, and the building vector information is written into the building vector information attribute;

step 2, calculating the shadow shielding surface area between buildings according to the vector information and the height information of the buildings by utilizing a polygon union algorithm in the calculation geometry, and obtaining the effective available area of the mountable photovoltaic equipment including the roof and the side elevation;

And 3, calculating the optimal inclination angle and the optimal installation distance of the photovoltaic equipment installed on the roof of the building by using the fixed installation type photovoltaic equipment, and obtaining the installed capacity and the photovoltaic potential of the photovoltaic equipment installed on the roof of the building by considering the shadow shielding area of the roof.

And further, in the step 1, building vector information is obtained by utilizing the multi-element space-time information, the roof area, the side elevation area and the height of the building are calculated according to the geometric characteristics of the building vector information, and the building vector information is written into the attribute of the building vector information. The method comprises the following steps:

step 1.1, generating building vector information according to multiple space-time information, such as data transmitted by high-resolution satellites and unmanned aerial vehicles, taking a high-resolution seventh remote sensing image as an example, and obtaining the vector information and the height information of the building by using the following methods;

step 1.1.1, vector information of a building is obtained by using a Unet convolutional neural network;

step 1.1.2, obtaining the height information of the building by using the DSM model and the DEM model.

And 1.2, calculating the side standing area, the roof area and the type of the roof of the building (flat roof or sloping roof) according to the building vector information and the height information.

Further, step 2, using the multiple space-time information to obtain building vector information, designing an automatic algorithm for calculating the shadow distribution of the building surface facing the photovoltaic potential analysis, and calculating the roof available area and the side elevation available area of the building by using the algorithm according to the vector information and the height information of the building group;

Step 2.1, for a building to be subjected to shadow analysis, searching vector information and height information of the building, the periphery of which is likely to generate shadow shielding on the surface of the building, by a searching method of the vector information of the building;

step 2.2, calculating a shadow polygon formed by shadows generated by the buildings according to the building vector information that the periphery of the target building possibly generates shadow shielding on the surface of the target building obtained in the step 2.1, and judging whether the polygon is intersected with a polygon corresponding to the target building vector information;

step 2.3, calculating a union set of shadow polygons generated by peripheral buildings of the target building in the step 2.2 according to a polygon union algorithm in the calculation geometry, namely a super polygon, and then replacing the shadow polygons generated by each building by the super polygon;

and 2.4, obtaining a roof shadow shielding area and a side elevation shadow shielding area corresponding to the target building vector information through space analysis and calculation of the hyper-polygon and the target building vector information, wherein the specific steps are as follows:

step 2.4.1, designing a polygon corresponding to the vector information of the target building to a certain distance along the incident direction of sunlight, and solving the intersection area of the polygon corresponding to the vector information of the target building and the super polygon at the moment, namely the area of the roof of the target building, which is shielded by shadow;

Step 2.4.2, calculating the area of the side elevation of the target building, which is shielded by the shadow, and specifically comprises the following steps:

step 2.4.2.1, taking the polygon corresponding to the building vector information as the plane representation of the three-dimensional building model, wherein the shadow distribution situation on each surface of the building is difficult to be directly displayed, and the following mathematical operation needs to be carried out on the polygon corresponding to the building vector information and the shadow polygon: and (2) solving an intersection of the polygon corresponding to the vector information of the target building and the super polygon, wherein the intersection contains shadow information on all surfaces of the target building, and the intersection is different from the shadow polygon of the roof of the target building obtained in the step (2.4.1) to obtain the polygon formed by the side elevation shadows of the target building. Dividing the polygon to divide the projection of the shadow on each side elevation of the target building;

step 2.4.2.2, calculating the shadow polygon and the area of the shadow polygon on each side elevation of the building according to the shadow projection polygon on each side elevation of the target building obtained in step 2.4.2.1;

step 2.4.3, subtracting the shadow shielding area from the total area of the building roof to obtain the mountable area of the building roof; subtracting the shadow shielding area of each side elevation of the building from the total area of each side elevation of the building to obtain the mountable area of each side elevation of the building;

Therefore, based on the space analysis method disclosed in the step 2, the surface shadow of the building can be directly calculated according to the building vector information and the solar radiation parameters, so that the calculation complexity of the link of analyzing the surface shadow area of the building by relying on three-dimensional modeling in the prior art is reduced, and the problem of low efficiency when the prior art is applied to large-area calculation of application scenes such as provincial areas is solved.

Further, step 3, calculating an optimal inclination angle and an optimal installation distance of the photovoltaic equipment installed on the roof of the building by using the fixedly installed photovoltaic equipment, and obtaining the installed capacity and the photovoltaic potential of the photovoltaic equipment installed on the roof of the building by considering the area of the roof shielded by the shadow, wherein the specific steps are as follows:

step 3.1, calculating the optimal inclination angle and the optimal distance of the roof-mounted photovoltaic equipment, wherein the method comprises the following specific steps of:

step 3.1.1, calculating an optimal inclination angle and an optimal distance of flat roof mounted photovoltaic equipment;

step 3.1.2, calculating the optimal inclination angle and the optimal distance of the pitched roof mounting photovoltaic equipment;

step 3.2, subtracting the shadow shielding area from the total area of the building roof to obtain the mountable area of the building roof, and further calculating the installed capacity and photovoltaic potential of the photovoltaic equipment mounted on the building roof;

Therefore, based on the method disclosed in the step 3, the influence factor of shielding the shadow of the surrounding building in the actual environment can be taken into consideration, the area of the photovoltaic available area of the building roof and each elevation which is not shielded by the shadow and the optimal inclination angle of the roof can be accurately calculated, and the problems that the photovoltaic available area of the side elevation of the building is ignored and the influence of shielding of the shadow of the surrounding building on the photovoltaic available area of the concrete roof in the actual environment cannot be accurately calculated in the prior art are solved.

The beneficial effects are that:

according to the building vector information, roof type and height information obtained from multi-element space-time information, an automatic algorithm for solving shadows of the roof and the side elevation of the building is designed by taking the information as a data source, and the available area of the roof and the available area of the side elevation of each building can be automatically calculated by using the algorithm so as to prepare for calculating the photovoltaic power generation potential of the building.

Drawings

FIG. 1, a flow chart of the method of the present invention;

FIG. 2, dataset sample effect diagram;

fig. 3 is a graph of roof outline polygon prediction effect corresponding to building vector information in Daxing area in Beijing city; (a) an original image, (b) a predicted result;

FIG. 4, building shadow occlusion scene simulation;

FIG. 5, building movement scene simulation;

FIG. 6, building movement side view simulation;

fig. 7, building movement plan simulation.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without the inventive effort based on the embodiments of the present invention are within the scope of protection of the present invention.

According to an embodiment of the present invention, as shown in fig. 1, a method for calculating a photovoltaic potential analysis available area of a building is provided, including the following steps:

step 1, building vector information is obtained by utilizing multi-element space-time information, the roof area, the side elevation area and the height of a building are calculated according to polygonal geometric features corresponding to the building vector information, and the building vector information is written into the attribute of the building vector information, and the specific steps are as follows:

step 1.1, generating building vector information according to data transmitted by a high-resolution satellite and an unmanned aerial vehicle;

A large amount of building vector information and height information can be obtained at one time by using a high-resolution satellite with a three-dimensional mapping function, and the specific method is as follows:

step 1.1.1, obtaining building vector information by using a Unet convolutional neural network;

the building outline polygon extraction mainly adopts a Unet semantic segmentation network, and the training is completed based on a homemade dataset. The sample is marked on partial images of Google data, high-score second data and high-score seventh data, then the sample set is manufactured through links such as data format conversion, data blocking and image slicing, and the effect of the finished sample is shown in figure 2.

The final data set has 384 x 384 pictures, which includes 2694 training sets, 582 verification sets and 136 test sets. Based on the Unet semantic segmentation network, training parameters are set, wherein the iteration times are 80000 times, the image batch size of each time is 4, and the initial learning rate is 0.003. After the final training is completed, the recall rate tested on the test set is 84.3%, the accuracy is 82.5%, the F1 precision value is 83.4%, and the effect of image prediction is shown in (a) and (b) of fig. 3.

Step 1.1.2, obtaining the height information of the building by using a DSM and DEM (Digital Elevation Model, DEM for short) model.

The invention uses GIS software to process the high-resolution seventh stereopair to obtain DSM (Digital Surface Model, DSM for short), inputs DSM and DEM in Arcgis grid calculator, calculates DSM-DEM to obtain normalized digital surface model (normalized Digital Elevation Model, nDSM for short). The nDSM records the height information of all the ground objects higher than the ground relative to the ground, and if the value of each pixel point in the nDSM is larger than 0, the value of the point, which indicates that the ground objects such as buildings, bridges or trees exist, is the height of the ground object, and the nDSM can be known to contain the height information of all the buildings. From the building roof profile polygons that have been obtained above, the slope and direction of the roof can be calculated using nsms.

There are also situations in the industry where unmanned airborne lidars are used to obtain building vector information and altitude information.

Lidar systems pulse laser light from unmanned aerial vehicle mobile systems through air and vegetation (aerial lasers) and even water (symmetric lasers). The scanner receives light (echo) and measures distance and angle. A technical means for actively mapping earth surface space information. And acquiring signals reflected by the detection target by actively transmitting laser pulses, and processing the signals to obtain the space information of the surface target. Therefore, the airborne laser radar technology has the advantage of being free from the restrictions of weather, illumination and other conditions. The method is commonly used for manufacturing high-resolution maps and is applied to measurement, geodetic measurement, geochemistry, archaeology, geography, geology, geomorphology, seismography, forestry, atmospheric physics, laser guidance, airborne laser mapping (ALSM) and laser altimeters.

The unmanned plane laser radar technology has the advantages of high speed of acquiring space information, high efficiency and safe operation. The airborne laser radar technology completes detection work through the flight of an aircraft and the scanning of laser pulses, can acquire large-area and large-range ground surface space information in a short time, and has higher working efficiency. Compared with the traditional manual measurement technical means, the method greatly reduces the workload, shortens the field measurement time and improves the detection work efficiency.

Among a plurality of methods for acquiring building vector information and height information, the high-resolution remote sensing image method has important significance. At present, a part of information of buildings in each province and city is stored in cadastral data of a local resource hall, and in recent years, a method for acquiring building information by using an unmanned aerial vehicle is gradually rising, and the following modes are compared. The conventional cadastral data of each province and city resource hall does not cover the requirement of photovoltaic construction, and an accurate building drawing is stored in confidential departments such as fire departments, so that the building has a certain confidentiality level, and in fact, parameters of civil buildings need to be measured or acquired by other means. Very accurate data of a building can be obtained by unmanned aerial vehicle or laser point cloud mode, but the cost is extremely high, and the requirement of estimating building parameters in a large area is not met. The high-resolution remote sensing data is used for acquiring the geometric shape, the height and the real-time shadow area of the surface of the building through a designed algorithm, the cost of the method is low, the remote sensing satellite can cover all provinces and cities nationwide, the on-site survey is not needed, and a large amount of labor cost and time cost are saved.

For satellites without a stereoscopic mapping function, a convolutional neural network such as the Unet can be used for obtaining building vector information, and a shadow height measurement method is used for calculating building height according to the shadow of a building, and the steps are as follows:

The satellite with the three-dimensional mapping function and the unmanned plane laser radar can obtain the height data (such as one meter by one meter) of the building roof with larger resolution, and the gradient and the slope direction of the building roof can be obtained easily according to the height change of each point of the roof.

The satellite without the three-dimensional mapping function can not directly obtain the height, gradient and slope direction information of a building, and the roof is a flat roof or a sloping roof can be judged by the following two methods, and the specific contents are as follows:

obtaining POI data (such as POI data of a Goldmap) of a building area, carrying out superposition analysis on polygons corresponding to the POI data and building vector information to obtain building types, carrying out statistics on the installation capability of photovoltaic equipment according to different building types, setting a reduction coefficient for each building type, multiplying the reduction coefficient after the roof and side elevation areas of the building are calculated, and then calculating the installation inclination angle and the installation interval of the photovoltaic equipment according to a flat roof.

And (3) using a deep learning method to sketch a sample of each building type, obtaining a classification model of the building type after learning by using a convolutional neural network, counting the installation capacity of the photovoltaic equipment according to different building types, setting a reduction coefficient for each building type, multiplying the reduction coefficient after the area of the roof and the side elevation of the building is calculated, and then calculating the installation inclination angle and the installation interval of the photovoltaic equipment according to the flat roof.

According to the polygon corresponding to the building vector information obtained in the step 1.1, the projection area of the building roof can be calculated, and the side standing area of the building can be calculated by the perimeter of the building roof and the height of the building, wherein the calculation formula is as follows:

C×H＝S

in the above formula, C represents the perimeter of the roof of the building, H represents the height of the building, and S represents the side-standing area of the building. The perimeter of the building roof in the above formula is changed into the length of each side of the building roof, and the area of each side elevation of the building is calculated.

And 2, calculating the surface area which is shaded between the large-area buildings according to the building vector information and the height information.

Urban area buildings are densely distributed, and a plurality of high-rise buildings are arranged, so that shielding phenomenon is easy to occur, and the direct sunlight cannot be accepted in some areas. In order to further optimize the accuracy of solar radiation estimation, the invention also considers the blocking effect of earth surface building shielding on direct radiation by introducing shadow analysis. In step 2, the influence of unevenness of the earth's surface is ignored, and if the earth's surface corresponding to a building unit is blocked by other adjacent buildings, it is necessary to determine whether the building unit can receive direct radiation by shadow analysis.

The method comprises the following specific steps:

and 2.1, searching building vector information of which the periphery is likely to generate shadow shielding on the surface of the building vector information to be subjected to shadow analysis by a searching method of the building vector information.

The invention uses a large-scale satellite data vector information gridding storage and query method to store building vector information, the method is compatible with a plurality of mature space gridding subdivision methods such as TMS, google Tiles and the like, and the specific steps are as follows: and meshing to divide the geographic space to form a multi-scale logic container, storing vector space information into the logic container in a uniform format supporting any extension attribute field in the running process, and taking a logic container group as a data management system to support rapid adding, deleting and modifying of the large-scale vector space information.

According to the method, a traditional single machine is used as a bottom storage device, and according to a mature tile storage method, the single machine is used for storing large-scale vector information and grid information such as a whole high-resolution remote sensing image, and building vector information which is likely to generate shadow shielding for a target building is quickly searched according to the longitude and latitude of the building vector information to be subjected to shadow analysis.

In an actual scene, the farther a building is from a polygon corresponding to building vector information to be subjected to shadow analysis, the more difficult the shadow is to cover a target building, because the height of the building is within a certain range, the shielding range of the shadow is limited, and thus the range of searching for surrounding buildings of the target building can be calculated in the following manner:

the height of the highest building among these is found from the inputted all building vector information, and is denoted as h.

Let the solar altitude at this point be γ, calculate the longest shadow that the highest building may produce:

length＝h×tanγ

where h represents the highest elevation of all buildings in the calculation, γ represents the solar elevation angle, and length represents the length of the longest shadow that the building may produce.

As long as the center point of the polygon corresponding to the building vector information is far from the center point of the target building by more than this length, no influence is exerted on the target building.

The method comprises the steps of converting coordinates by using a large-scale vector information searching method, converting a distance range into a range of tiles, extracting building vector information in the tiles, and taking the building vector information as building vector information which can generate shadow shielding for a target building.

Step 2.2, step 2.1 have searched for building vector information that may produce shadow occlusion for the periphery of the target building, calculate the shadow polygon corresponding to these vector information, and judge whether it intersects with the target polygon, the concrete steps are as follows:

for a building to be subjected to shadow analysis, building vector information and height information, the periphery of which is likely to generate shadow shielding on the surface of the building, are searched by a building vector information searching method.

The following describes the calculation of building shadows from building information, solar azimuth information, which shadows can be described as a set of building shadows.

Building vector information is a formalized representation of the relevant attributes of a polygon in a geographic space, and has the longitude and latitude geographic coordinates of all points of the polygon, namely the geometric information of the point columns.

Since the building vector information contains the height information of the building, the height of the building is known and can be referred to as h ₂ 。

The outline of the building is formed by connecting vertexes, so that the outline of the shadow is also a polygon, coordinates of all points in the shadow polygon are calculated, and the coordinates of one point in the polygon corresponding to the vector information of the building are marked as x ₁ ,y ₁ Substituting the formula to calculate the coordinates of the shadow polygon.

Wherein x is ₁ ,y ₁ x ₂ ,y ₂ The method comprises the steps of respectively representing coordinates of polygon vertexes corresponding to building vector information and corresponding shadow polygon vertexes under a plane rectangular coordinate system, wherein beta represents a solar azimuth angle, theta represents a solar altitude angle, the shadow polygon is a result after translation and affine transformation of a polygon corresponding to the building vector information, and x and y coordinates can be converted into longitude and latitude coordinates after calculation is finished.

And calculating each vertex of the polygon corresponding to the building vector information through the equation above to obtain a shadow polygon corresponding to the building vector information, establishing a shadow vector information for each shadow polygon, wherein the attribute part of the shadow vector information stores the attribute information of the polygon corresponding to the building vector information corresponding to the shadow polygon, and the geometric part of the shadow vector information stores the geometric information of the shadow polygon.

After calculating the shadow polygon vector corresponding to each piece of building vector information around the target building, it is conceivable that if the surrounding building of the target building stands up, tens of building shadow polygons can be obtained in the previous step, at this time, the shadow polygons are screened, the shadow polygons intersecting the polygon corresponding to the target building vector information are selected, and the shadow polygons not intersecting the polygon corresponding to the target building vector information do not shade the surface of the target building. The rest shadow polygons can be saved in a buffer queue to wait for the next target building to be calculated for later use.

Step 2.3, calculating a union set of shadow polygons generated by surrounding buildings of the target building calculated in the step 2.2 according to a polygon union algorithm in calculation geometry, which is called a super polygon, and then replacing the shadow polygons generated by each building with the super polygon;

a large number of surrounding buildings generate shadow polygons with different shapes at the positions of a target building, each shadow polygon is a shadow striking the target building, belongs to a part of the shadow of the surface of the target building, all the shadow polygons are overlapped to form the shadow of the surface of the target building, and if each shadow polygon is calculated independently to occupy the area of the surface of the target building, the shadow polygons have mutually overlapped parts, which may lead to a larger final calculation result and lead the calculation result to be far away from the true value.

Thus, alternatively, the invention uses the algorithm of calculating the union and intersection of polygons and their areas in the university of Hunan mathematics and computer science institute Wei Xuqing, calculates the union of all shadow polygons intersecting the target building, and then calculates only the shadows that the superpolygon causes to the target building, the specific steps of the algorithm are as follows:

(1) And establishing a vertex table of the main polygon and the auxiliary polygon. (2) And solving intersection points of the main polygon and the auxiliary polygon, and sequentially inserting the intersection points into the two polygon tables to establish a bidirectional pointer. (3) If there are vertices that have not been tracked, the following operations are performed: any vertex which is not tracked is selected from the main polygon table as a starting point, the vertex is output to the union table, the polygon boundary is tracked, the original vertex or the intersection point is output to the union table, and if the intersection point is the intersection point, the tracking direction is changed through a bi-directional pointer until the starting point is encountered.

And 2.4, obtaining the roof shadow shielding area and the side elevation shadow shielding area of the target building by carrying out space analysis and calculation on the polygon corresponding to the hyper-polygon and the vector information of the target building, wherein the specific steps are as follows:

step 2.4.1, calculating the area of the roof of the target building, which is shielded by the shadow, and specifically comprises the following steps:

for each vertex x1, y1 of the polygon corresponding to the target building vector information, the following steps are performed:

wherein x is ₂ ,y ₂ The vertex of the polygon corresponding to the vector information of the target building after translation is represented, beta represents the solar azimuth angle, theta represents the solar altitude angle, h represents the altitude of the target building, and the meaning of the expression simulates the following scene:

The shadow generated by other buildings is fully distributed on the place where the target building is located, the target building is taken off, the shadow is cast on the flat ground where the target building is located to form a shadow polygon, then the target building is slowly pushed back to the original position by hands along the direction of the incident angle of the sun, and the shadow is imagined to be beaten on the side elevation of the target building at the beginning, because the roof has a certain height and cannot be blocked at the beginning, the shadow polygon on the flat ground is receded again as the building is also increasingly returned to the original position until the shadow on the side elevation penetrates through the height of the side elevation, and the redundant shadow is beaten on the roof of the target building at the moment.

And obtaining the polygon corresponding to the vector information of the target building after translation according to the calculation, wherein the area of the intersecting part of the polygon corresponding to the vector information of the target building is the area of the part of the roof of the target building, which is shielded.

According to one embodiment of the invention, sketchup software is used for modeling the situation that surface shadow shielding is generated among buildings, and the method for moving the target building polygon to obtain the building roof shadow is intuitively demonstrated. As shown in fig. 4, a situation of three buildings is simulated, sunlight is incident from the front south to the front north, the north-most building is targeted, two north-most buildings are higher, shadows generated by the two north-most buildings fall on the north-most buildings, a polygon formed by shadows generated by the first two buildings completely encloses the north-most buildings, the actual shadows of the roofs of the target buildings are calculated by using the method for moving the target buildings without three-dimensional modeling, and a schematic top view after movement is shown in fig. 5:

It can be seen that the intersection of the shadow polygon formed by the shadows of the two buildings in the south (excluding the target building and the target building after the movement) and the polygon corresponding to the vector information of the target building after the movement is completely identical to the shadow polygon of the roof of the original target building.

At this time, the middle building is moved to north slowly, because the height of the middle building is higher than the building at the north most, it is known that the latter building must generate shadow shielding on the roof of the former building when the two buildings are completely attached, and the latter building is moved until it is stopped when it will generate shadow shielding on the surface of the former building, as shown in fig. 6:

at this time, as can be seen from the top view schematic diagram of fig. 7, the lower edge of the shadow polygon generated by the latter building is also moved to the north, and the lower edge of the moved target building is attached at the same time, i.e. the polygons corresponding to the vector information of the moved target building are intersected. From the above experiments, it is known that the target building and other buildings generate shadows on the target building, and the polygon corresponding to the vector information of the moved target building has a synchronous geometric relationship with the hyper-polygon.

and 2.4.2.1, intersecting the polygon corresponding to the target building vector information with the super polygon calculated in the step 2.3, wherein the side elevation of the target building is provided with a part which is shaded, otherwise, the surface of the target building is not shaded by other buildings. The polygon corresponding to the building vector information is used as the plane representation of the three-dimensional building model, so that the shadow distribution situation on each surface of the building is difficult to be directly displayed, and the following mathematical operations are needed to be carried out on the polygon corresponding to the building vector information and the shadow polygon: and (2) solving an intersection of the polygon corresponding to the vector information of the target building and the super polygon, wherein the intersection contains shadow information on all surfaces of the target building, and obtaining a polygon where the shadow of the side elevation of the target building is h by performing difference between the intersection and the shadow polygon of the roof of the target building obtained in the step (2.4.1). The polygon is segmented to demarcate the projection of shadows on each side elevation of the target building. Under the premise, the invention provides a method for calculating the shadow area on each side elevation of the polygon corresponding to the vector information of the target building, which can accurately provide a reference for calculating the installed capacity of each side. The first step is to divide the hyper-polygon, which is a set of projections of shadows on each side-elevation of the building, i.e. in the total shadow projection the projections of shadows on each side-elevation of the building are divided. The super polygon is intersected with the polygon corresponding to the vector information of the target building, if the intersected part comprises the vertexes of the polygon corresponding to the vector information of the target building, each vertex is used as a straight line in the solar azimuth direction, and the intersected part is segmented; otherwise, the shadow is only fallen into one side elevation of the polygon corresponding to the building vector information, and the segmentation is not needed.

And 2.4.2.2, calculating the shadow polygon and the area of the shadow polygon on each side elevation of the building according to the shadow projection polygon on each side elevation of the target building obtained in the step 2.4.2.1.

The polygon corresponding to the vector information of the target building is intersected with the hyper-polygon, which indicates that the side elevation of the target building has a part which is blocked by shadow, otherwise, indicates that the surface of the target building is not blocked by other buildings. The polygon corresponding to the building vector information is used as the plane representation of the three-dimensional building model, so that the shadow distribution situation on each surface of the building is difficult to be directly displayed, and the following mathematical operations are needed to be carried out on the polygon corresponding to the building vector information and the shadow polygon: and solving an intersection of the polygon corresponding to the vector information of the target building and the super polygon, wherein the intersection contains shadow information on all surfaces of the target building, and the intersection is differenced with the shadow polygon of the roof of the target building obtained in the previous step to obtain the shadow polygon of the side elevation of the target building. The polygon is segmented to demarcate the projection of shadows on each side elevation of the target building. Under the premise, the invention provides a method for calculating the shadow area on each side elevation of the polygon corresponding to the vector information of the target building, which can accurately provide a reference for calculating the installed capacity of each side.

Light passes through an opaque object, shadows are generated, once the shadows are generated, the shadows are always displayed on the surface of a ground object, a hyper-polygon formed by shadow polygons represents the union of shadows projected to the ground by buildings around a target building, and when the shadow polygons intersect with the target building polygons, a part of shadows are displayed on the surface of the target building, a part of shadows are displayed on the roof of the target building, a part of shadows are displayed on the side elevation of the target building, the shadows displayed on the side elevation have a stretching effect due to the sun height, and therefore, the shadow area of the side elevation is equal to the total shadow area minus the area of the shadows on the roof, and the calculation formula is as follows:

S _facade ＝S-S _roof

S _facade ＝S _f1 +S _f2 +…+S _fn

wherein S represents the area of the hyper-polygon representing the roof shadow and the side elevation shadow, S _roof Representing the area occupied by the roof shadow in the hyper-polygon, S _facsde Representing the projected area of a side elevation shadow in a hyper-polygon, μ representing the acute angle of the sun's incident angle with respect to the edge of the corresponding side. The target building has n side vertical surfaces, each side vertical surface has a corresponding shadow area, and the first surface is taken as an example and is marked as S _f1shade Its corresponding projection area in the hyper-polygon is S _f1 There is a trigonometric relationship between them.

Step 2.4.3, subtracting the shadow shielding area from the total area of the building roof to obtain the mountable area of the building roof; subtracting the shadow shielding area of the side elevation from the total area of each side elevation of the building to obtain the mountable area of each side elevation of the building.

in the northern hemisphere, in order to maximize the power generation of photovoltaic panels per unit area, photovoltaic panels on flat roofs are generally oriented in the very south direction and, for well-supported flat roofs, are often mounted at an optimal tilt angle. The local optimum installation inclination angle determined by the maximum annual solar radiation amount is shown as the following formula:

Wherein beta is _opi Indicating the optimum tilt angle, which can be obtained by a traversal search, G (a) indicates the radiation amount in the case of the tilt angle a.

For planar roofs, when installed with optimal tilt angles, the problem of photovoltaic panels in the photovoltaic array blocking each other is unavoidable, and therefore a reasonable design of the photovoltaic panel array spacing is required to minimize losses due to blocking shadows. The pitch of the photovoltaic panel array needs to comprehensively consider parameters such as local latitude, solar altitude, solar azimuth, roof slope, slope azimuth, array orientation, inclination and the like. The design of the minimum distance between the front and the rear of the array is generally based on the principle that the front and the rear of the array are not shielded from each other in the winter to 9 am to 5 pm. d is the spacing between two photovoltaic panels in the array. The spacing d is calculated mainly using the photovoltaic panel installation tilt angle θ, the solar azimuth angle α, the solar altitude angle h, and the length l of the photovoltaic panel.

The specific formula is as follows:

d＝l·cosθ+l·sinθ·coth·cosα

slope roof available area (S) _a ) The total area of the sloping roof minus the area of the sloping roof covered by the shadow is expressed, and the photovoltaic panel area is calculated according to the above formula (S _a ) And sloping roof available area (S) _rf ) The relationship of (2) is as follows:

and 3.1.2, calculating the optimal inclination angle and the optimal spacing of the pitched roof mounted photovoltaic equipment.

The pitched roof is a roof model adopted by traditional residences in China, and due to the advantages of the pitched roof in the aspects of water resistance, heat preservation, heat insulation and the like, the factors such as wind load of a photovoltaic panel, cost of a fixing device and the like are considered in urban houses at present, and the pitched roof is generally installed in a tiled mode. Also, for pitched roofs, five directions, east, southeast, south, southwest, and west, are generally considered to be suitable for installing photovoltaic. As the pitched roof adopts a tiled installation mode, the front and back shielding problem of the flat roof photovoltaic array can be avoided, and the roof area can be effectively utilized.

And 3.2, subtracting the shadow shielding area from the total area of the building roof to obtain the mountable area of the building roof, wherein the optimal inclination angle and the optimal distance of the photovoltaic equipment calculated according to the step 3.1 can be used for covering all east Asia areas by using the meteorological data of a solar radiation library, such as Himaware satellite, and the Himaware satellite data provides meteorological data with time resolution of 1 hour and spatial resolution of 0.04 longitude and latitude, and mainly comprises wind speed, temperature, air pressure and GHI, DNI, DHI. The installed capacity and the generating potential of the building roof are calculated, and the concrete steps are as follows:

Calculating the power generation capacity of the photovoltaic system firstly requires calculating the installed capacity of the photovoltaic system. In the case of known architectural photovoltaic installable areas, for roof photovoltaics, the fill factor (PF) is defined as the ratio of the installed photovoltaic panel area to the extracted architectural photovoltaic installable area. Obviously, the filling factor of a pitched roof adopting a tiling installation mode is 1, and the filling factor of a flat roof can be calculated by the following formula:

PF _hor ＝L/D＝[cosβ+(sinβ/tanα)·cosAZ _m ] ^-1

wherein PF is _hor Representing the fill factor of a flat roof, l is the length of the photovoltaic panels, d is the spacing between the photovoltaic panels, and α is the solar altitude. It is evident that the fill factor on a flat roof is related to the installation tilt angle beta of the photovoltaic panel,

based on the adopted specific photovoltaic panel type number information, the installed capacity of the photovoltaic system is calculated and obtained:

Cap＝S·PF·P _STC /S _panel

wherein Cap represents a flat roofIs the installed photovoltaic capacity of S, S represents the roof area, P _STC And S is _panel The rated output power and area of the photovoltaic panel are shown, respectively.

After the installed capacity of the photovoltaic system is obtained, the local meteorological data and the parameters of the photovoltaic system are combined,

from the solar radiation data in the multivariate data, the solar radiation data may be a nationwide high resolution surface solar radiation data set, such as Himaware satellite data, which provides weather data with a time resolution of 1 hour and a spatial resolution of 0.04 longitude and latitude, denoted G _src . The power generation amount can be calculated:

E＝η _INV ·Cap·(G/G _STC )·[1-τ·(T _work -T _STC )]·△t

wherein E represents the power generation amount of the photovoltaic equipment within a certain time period, deltat represents the length of the time period, eta _INV Representing inverter efficiency, cap represents the total amount of photovoltaic installed on a flat roof, G represents illumination intensity, G _STC Represents the illumination intensity under the standard working condition, tau represents the heat loss efficiency, T represents the working temperature of the photovoltaic cell and T _STC Indicating the operating temperature of the photovoltaic cell under standard operating conditions.

While the foregoing has been described in relation to illustrative embodiments thereof, so as to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, but is to be construed as limited to the spirit and scope of the invention as defined and defined by the appended claims, as long as various changes are apparent to those skilled in the art, all within the scope of which the invention is defined by the appended claims.

Claims

1. The method for calculating the available area of the building photovoltaic potential analysis is characterized by comprising the following steps of:

step 3, calculating the optimal inclination angle and the optimal installation distance of the photovoltaic equipment installed on the roof of the building by using the fixedly installed photovoltaic equipment, and taking the shadow shielding area of the roof into consideration to obtain the installed capacity and the photovoltaic potential of the photovoltaic equipment installed on the roof of the building;

the local optimum installation inclination angle determined by the maximum annual solar radiation amount is shown as the following formula:

Wherein beta is _opi Indicating an optimum tilt angle, obtained by a traversal search method, G (a) indicating an amount of radiation in the case where the tilt angle is a;

the distance d is calculated by using the installation inclination angle theta, the solar azimuth angle alpha, the solar altitude angle h and the length l of the photovoltaic panel, and the specific formula is as follows:

d＝l·cosθ+l·sinθ·coth·cosα

the usable area of a planar roof means the total area of the planar roof minusThe area of the planar roof covered by the shadow is calculated to obtain the photovoltaic panel area S according to the formula _a Planar roof available area S _rf The relationship of (2) is as follows:

the sloping roof is installed in a tiling mode;

and 3.2, subtracting the shadow shielding area from the total area of the building roof to obtain the mountable area of the building roof, and calculating the mounting capacity and the generating potential of the building roof by using a solar radiation library according to the optimal inclination angle and the optimal distance of the photovoltaic equipment calculated in the step 3.1, wherein the specific steps are as follows:

calculating the power generation capacity of a photovoltaic system firstly requires calculating the installed capacity of the photovoltaic system; in the case of known building photovoltaic installable areas, for roof photovoltaics, defining a fill factor as the ratio of the installed photovoltaic panel area to the extracted building photovoltaic installable area; the filling factor of the pitched roof adopting the tiling installation mode is 1, and the filling factor of the flat roof is calculated by the following formula:

PF _hor ＝l/d＝[cosθ+(sinθ/tanh)·cosα] ^-1

Wherein PF is _hor Representing the filling factor of a flat roof, l being the length of the photovoltaic panels, d being the spacing between the photovoltaic panels;

Cap＝S·PF·P _STC /S _panel

wherein Cap represents the photovoltaic installed capacity of a flat roof, S represents the area of the roof, and P _STC And S is _panel Respectively representing rated output power and area of the photovoltaic panel;

according to solar radiation data in the multivariate data, calculating to obtain generated energy:

E＝η _INV ·Cap·(G/G _STC )·[1-τ·(T _work -T _STC )]·Δt

wherein E represents the power generation amount of the photovoltaic equipment in a certain time period, delta t represents the length of the time period, eta _INV Representing inverter efficiency, cap represents the total amount of photovoltaic installed on a flat roof, G represents illumination intensity, G _STC Represents the illumination intensity under the standard working condition, tau represents the heat loss efficiency and T _work Indicating the operating temperature of the photovoltaic cell, T _STC Indicating the operating temperature of the photovoltaic cell under standard operating conditions.

2. The method for calculating the available area of the photovoltaic potential analysis of the building according to claim 1, wherein the step 2 is specifically as follows:

step 2.1, for building vector information to be subjected to shadow analysis, searching building vector information, the periphery of which is likely to generate shadow shielding on the surface of the building vector information, by a building vector information searching method;

Step 2.2, calculating shadow polygons corresponding to the building vector information according to the building vector information, which is obtained in the step 2.1, of which the periphery of the target building is likely to generate shadow shielding on the surface of the target building, and judging whether the shadow polygons intersect with the target polygons or not;

step 2.3, obtaining a union set of shadow polygons generated by surrounding buildings of the target building, namely super polygons, which are obtained by calculation in the step 2.2, and then replacing the shadow polygons generated by each building by using the super polygons;

and 2.4, obtaining the roof shadow shielding area and the side elevation shadow shielding area corresponding to the target building vector information through space analysis and calculation of the hyper-polygon and the target building vector information.

3. The method for calculating the available area for analyzing the photovoltaic potential of the building according to claim 2, wherein the step 2.1 is to search the building vector information of which the periphery is likely to generate shadow shielding on the surface of the building vector information to be subjected to shadow analysis by a searching method of the building vector information, and specifically comprises the following steps:

the geographic space is divided through gridding to form a multi-scale logic container, vector space information is stored in the logic container in a unified format supporting any extension attribute field in operation, a logic container group is used as a data management system, rapid addition, deletion and improvement of large-scale vector space information is supported, and building vector information, which is possibly shaded on the surface, of the periphery of a target building is rapidly searched according to longitude and latitude of building vector information to be subjected to shadow analysis.

4. The method for calculating the available area of the photovoltaic potential analysis of the building according to claim 2, wherein the step 2.4 is specifically as follows:

step 2.4.1, calculating the area of the roof of the target building, which is shielded by the shadow;

2.4.2.1, dividing the hyper-polygon, wherein the hyper-polygon is a set of shadows cast on each side elevation of the building, and the hyper-polygon is divided, namely, in the total shadows cast, the shadows cast on each side elevation of the building are divided;

step 2.4.2.2, calculating the area of shadows on each side elevation of the building;