A calculation method for building solar energy acquisition potential index

Abstract

The present invention belongs to the field of architectural design and discloses a method for calculating a building's solar energy acquisition potential index. The method comprises the following steps: obtaining the solar azimuth and solar altitude corresponding to sunrise and sunset to form a fan-shaped calculation range, and obtaining a plurality of calculation line segments within the fan-shaped calculation range; obtaining the tangent value of the solar altitude at the time corresponding to the calculation line segment, and the ratio of the height of the blocking building to the distance between the blocking building and the building to be measured, and subtracting the tangent value of the solar altitude from the ratio to obtain a difference; obtaining the approximate direct solar irradiance at the time corresponding to the calculation line segment, and assigning the approximate direct solar irradiance as a weight to the difference to obtain a weighted value; obtaining the central angle ratio of the area to be measured, and obtaining the building shielding factor of the building to be measured based on the central angle ratio and the weighted value. The present invention can be used to compare, select, and optimize different building complex layout plans from the perspective of solar energy acquisition potential.

Description

Technical Field

[0001] The invention belongs to the field of architectural design, and in particular relates to a method for calculating a building solar energy acquisition potential index. Background Art

[0002] Promoting the application of renewable energy in buildings is an important means to reduce building carbon emissions. As a ubiquitous, clean and pollution-free renewable energy source, the application of solar energy in the construction field is of great significance for reducing building energy consumption and carbon emissions.

[0003] Current solar energy utilization in buildings, whether through active use of external equipment or passive use through architectural form, materials, and structural design, relies on a prerequisite: the building itself can receive sufficient solar radiation. Therefore, when designing a building's solar energy utilization, architects must first estimate the building's potential for solar radiation.

[0004] The solar energy harvesting potential of a single building is influenced by a variety of factors, including building orientation, width-to-depth ratio, building height, inter-building shading, and the building's own shading. Studies have found that as urban building density increases, building roofs and facades are often blocked by surrounding buildings, becoming a major factor affecting a building's solar energy harvesting potential and significantly impacting the solar energy utilization efficiency of its photovoltaic and solar thermal systems. Therefore, it is necessary to assess a building's solar energy harvesting potential by considering the degree of inter-building shading. New indicators and calculation methods are proposed to minimize inter-building shading and maximize solar energy harvesting efficiency, providing architects with targeted guidance in the early stages of building design.

[0005] Currently, the solar energy harvesting potential of buildings is primarily assessed using two methods, both requiring the use of complex simulation software. First, existing building design standards often use "sunshine duration" to characterize solar radiation gain. For example, the "Urban Residential Area Planning and Design Standard" (GB50180-2018) requires buildings in different regions to receive a certain number of hours of sunshine on the Great Cold Day or the Winter Solstice. Some sunshine duration calculation software can provide architects with some guidance in the early stages of building design by considering interbuilding shading. However, this method only ensures that rooms in a building meet basic sunshine duration requirements. Because solar irradiance (the amount of radiation received by an object per unit time and per unit area) varies at different times, cumulative sunshine duration alone cannot accurately assess a building's solar energy harvesting potential. Solar irradiance must be factored into the calculation process. Second, the solar energy harvesting potential of new or existing buildings can be assessed from the perspective of "sunshine radiation," by calculating the total annual solar radiation received by the building's exterior surfaces (facade and roof) or the annual solar radiation received per unit area. This method can relatively accurately calculate the amount of solar radiation received by the total exterior surface and per unit area of a building. However, the calculated results only represent the potential for a building to obtain solar energy under a combination of multiple influencing factors. It cannot represent the impact of a single factor (such as mutual shading between buildings) on the solar energy acquisition potential. The degree of influence of each influencing factor on the solar energy acquisition potential is the basis for architects to adjust and optimize the preliminary scheme. Therefore, this method cannot guide the preliminary scheme design. It is necessary to construct design indicators that reflect each influencing factor to conduct targeted assessments of the building's solar radiation acquisition potential. Some scholars have proposed design indicators to characterize the building's solar energy utilization potential based on different influencing factors, but no design indicators have been proposed to characterize the solar energy acquisition potential from the perspective of mutual shading between buildings.

[0006] Compare this to the patent titled "A Method for Calculating the Three-Dimensional Solar Energy Potential of a Building" (Application Number: 202010078768.6). This patent estimates the solar energy potential of existing buildings. The specific estimation method is to first perform a joint sampling of the roof and facade of the existing building model, then perform an occlusion analysis and a sky view analysis to calculate the direct and scattered solar radiation, ultimately deriving the average annual total radiation available to the building. This invention focuses on estimating the solar energy utilization potential of existing buildings. The result obtained is only the overall building's solar energy potential under a comprehensive analysis of multiple influencing factors. It cannot characterize the degree of influence of various factors, including mutual occlusion between buildings, on the building's solar energy acquisition. It also cannot provide a clear and targeted path and method for building form layout design and optimization (based on the various factors affecting the building's solar energy potential) in the early stages of the building plan to guide architects in the early design phase and maximize the building's solar energy potential. Therefore, a method is needed to characterize the impact of mutual occlusion between buildings on the solar energy acquisition potential. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for calculating a building solar energy acquisition potential index to solve the problems existing in the above-mentioned prior art.

[0008] To achieve the above object, the present invention provides a method for calculating a building solar energy acquisition potential index, comprising the following steps:

[0009] Obtain the solar azimuth angle and solar altitude angle corresponding to the sunrise and sunset times to form a fan-shaped calculation range, and obtain a number of calculation line segments within the fan-shaped calculation range;

[0010] Obtaining the tangent value of the solar altitude angle at the corresponding moment of the calculation line segment, the ratio of the height of the blocking building to the distance between the blocking building and the building to be measured, and subtracting the tangent value of the solar altitude angle from the ratio to obtain a difference;

[0011] Obtaining the approximate direct solar irradiance at the time corresponding to the calculation line segment, and assigning the approximate direct solar irradiance as a weight to the difference to obtain a weighted value;

[0012] The central angle ratio of the area to be measured is obtained, and based on the central angle ratio and the weighted value, the value of the building occlusion factor of the building to be measured is obtained.

[0013] Preferably, the process of obtaining the fan-shaped calculation range includes obtaining the center point of the intersection line of the base outline of the building to be measured and the south facade as the measurement point, and based on the solar azimuth corresponding to the sunrise and sunset times, drawing the projection line of the sunlight corresponding to the sunrise and sunset times on the horizontal plane with the measurement point as the center of the circle to obtain the fan-shaped calculation range.

[0014] Preferably, the process of obtaining the plurality of calculated line segments includes: taking the measurement point as the center point, rotating the radius line segment of the calculation range clockwise to obtain a unique intersection point between the radius line segment and the blocking building; connecting the measurement point and the unique intersection point to obtain a plurality of boundary line segments, and simultaneously obtaining a plurality of blocked areas and unblocked areas;

[0015] Obtain the angle bisector segments of the blocked area and the unblocked area; the plurality of boundary segments, the plurality of angle bisector segments, the sunrise projection line, and the sunset projection line are calculation segments within the calculation range.

[0016] Preferably, if the difference is a positive number, there is no occlusion on the building to be measured; if the difference is a negative number, there is occlusion on the building to be measured.

[0017] Preferably, the process of obtaining the value of the building occlusion factor of the building to be tested includes assigning weight values of the corresponding angle ranges to the average values of the weighted values corresponding to the occluded area and the unoccluded area, and performing summation processing to obtain the final value of the building occlusion factor of the building to be tested.

[0018] Preferably, the process of obtaining the average value of the weighted values corresponding to the occluded area and the unoccluded area includes obtaining the weighted values of the corresponding calculation segments in the occluded area and the unoccluded area, and the average value of the weighted values of the corresponding calculation segments is the average value of the weighted values corresponding to the occluded area and the unoccluded area.

[0019] Preferably, the process of obtaining the weight value of the angle range of the occluded area and the unoccluded area includes obtaining the weight value of the angle range of the occluded area and the unoccluded area based on the ratio of the central angle corresponding to the occluded area and the unoccluded area to the fan calculation range.

[0020] The technical effects of the present invention are:

[0021] (1) The present invention obtains the approximate direct solar irradiance at the corresponding moment of each calculation line segment, and assigns the irradiance as a weight to the difference to obtain a weighted value. The higher the irradiance, the greater the weight of the difference, the higher the quality of solar energy at this azimuth angle, and the more it should be obtained by the building. The quality of solar energy at different moments is included in the calculation, which is more scientific and accurate than the traditional building "sunshine hours" method.

[0022] (2) By calculating the building shielding factor, the present invention can quantitatively compare the differences in the influence of mutual shielding factors between buildings on specific building units under different building group layouts under the conditions of the same site area and the same volume ratio, and then compare the differences in solar energy acquisition potential. This can provide a reference for the layout optimization of the building group where the specific building unit is located in the early stage of the scheme design.

[0023] (3) The present invention can be used to compare, select and optimize different building complex layout plans from the perspective of solar energy acquisition potential, and can also be used to evaluate the solar energy utilization potential of specific building units in an existing building complex. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0025] Figure 1 A basic principle diagram for calculating the difference between the tangent value of the solar altitude angle at a corresponding moment of a certain line segment and the ratio of the height of the blocking building to the distance between the blocking building and the measured building in an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of a sector calculation range in an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of an obstructed area and an unobstructed area in an embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of all calculated line segments and the solar azimuth angle corresponding to each line segment in an embodiment of the present invention;

[0029] Figure 5 This is a three-dimensional schematic diagram of calculating the tangent value of the solar altitude angle corresponding to all line segments and calculating the ratio of the height of the blocking building to the distance between the blocking building and the measured building in an embodiment of the present invention;

[0030] Figure 6 is an overall three-dimensional schematic diagram of an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of a design of a first scheme for a residential development project in Lhasa according to an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of a design of a second scheme for a residential development project in Lhasa according to an embodiment of the present invention;

[0033] Figure 9 Flowchart of the calculation method in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0036] Example 1

[0037] like Figure 1-9 As shown, this embodiment provides a method for calculating a building solar energy acquisition potential index. For a residential development project in Lhasa, two design schemes are selected under the existing surrounding building environment conditions, and the one with the greater solar energy acquisition potential is selected.

[0038] Specific steps: First, calculate the occlusion factor Vof1 of scheme 1.

[0039] Step 1: Calculate the solar azimuth angle corresponding to the sunrise and sunset times on the winter solstice (December 21) in Lhasa at the building's location. There are two ways to do this: one is to calculate using formula (1); the other is to obtain the sunrise and sunset times and solar azimuth angle at the building's location by reading the CSWD meteorological data for the typical meteorological year used for the building.

[0040] As n =180°-arccos[(sinHs·sinφ-sin(-23°26′)) / (cosHs·cosφ)](1)

[0041] Among them As n is the solar azimuth (due north is 0°, clockwise is a positive azimuth), Hs is the solar altitude angle, and φ is the geographic latitude.

[0042] Let ∠Hs = 0°, and the calculated azimuths at sunrise and sunset are 117.3° and 242.7° respectively. The calculation range is between 117.3° and 242.7°.

[0043] Step 2: Draw the fan-shaped calculation range. Take the center point of the intersection line of the base outline of the measured building (B0) and the south facade as the measurement point A. According to the azimuth angle at sunrise and sunset, draw the projection line L of the sun's rays on the ground plane at sunrise and sunset with point A as the center of the circle. s , L j , and form a fan-shaped range (south-facing fan-shaped) with a central angle of α (α = 125.4°) and a certain radius length (the length can cover the blocking building and the measured building range), which is the calculation range.

[0044] Step 3: Divide the blocked area and the unblocked area. Within the range of the central angle α, with the measurement point (A) as the center point, rotate the radius line segment Ls (sunrise projection line) of the fan-shaped calculation range clockwise. When the building planes of each blocking building (B1, B2, B3) in Ls have only one intersection point, connect the measurement point A and this intersection point to generate a boundary line segment within the calculation range. A total of 6 boundary line segments are generated, which are represented as L 1a , L 1b , L 2a , L 2b , L 3a , L 3b At the same time, three fan-shaped occlusion areas with central angles of β1, β2, and β3 are formed; four unoccluded areas are also naturally formed, which are represented as fan-shaped unoccluded areas with central angles of γ1, γ2, γ3, and γ4 respectively.

[0045] Step 4: Determine all the calculated line segments within the calculation range (including the blocked area and the unblocked area). Draw the angle bisector of the central angle of the fan-shaped blocked area and intersect with the blocking building to generate three line segments, which are represented by L 1c , L 2c , L 3c ; Make the angle bisector L of the central angle of the fan-shaped unobstructed area 1w , L 2w , L 3w , L 4w Therefore, it can be determined that all calculated line segments (hereinafter referred to as "line segments") include: boundary line segment L 1a , L 1b , L 2a , L 2b , L 3a , L 3b , the angle bisector segment L of the occlusion area 1c , L 2c , L 3c and the angle bisector segment L of the unobstructed area 1w , L 2w , L 3w , L 4w , and finally includes the line segments L corresponding to sunrise and sunset s , L j The subsequent steps are all expanded and calculated based on these line segments (because the length of the angle bisector segment in the unobstructed area and the line segments corresponding to sunrise and sunset will not affect the calculation results, their length can be equal to the sector radius length in step 2 when drawing).

[0046] Step 5: Calculate the solar azimuth Asx corresponding to all line segments. Consider all line segments as the projection lines of the sun's rays on the horizon at a certain moment, and the clockwise angle between them and the true north is the azimuth Asx. The boundary line segment L can be obtained. 1a , L 1b , L2a , L 2b , L 3a , L 3b Corresponding to the azimuth angles ∠1a, ∠1b, ∠2a, ∠2b, ∠3a, ∠3b, the occlusion area angle bisector segment L 1c , L 2c , L 3c The corresponding azimuth angles ∠1c, ∠2c, and ∠3c, and the unobstructed area angle bisector L 1w , L 2w , L 3w , L 4w Corresponding values of azimuth angles ∠1w, ∠2w, and ∠3w.

[0047] Step 6: Calculate the tangent value T of the solar altitude angle corresponding to all line segments. Calculate the solar altitude angle corresponding to each azimuth angle using formula (1). The boundary line segment L can be obtained. 1a , L 1b , L 2a , L 2b , L 3a , L 3b Corresponding solar altitude angle ∠H 1a , ∠H 1b , ∠H 2a , ∠H 2b , ∠H 3a , ∠H 3b The value of the occlusion area angle bisector segment L 1c , L 2c , L 3c Corresponding solar altitude angle ∠H 1c , ∠H 2c , ∠H 3c Value; unobstructed area angle bisector L 1w , L 2w , L 3w , L 4w Corresponding altitude angle ∠H 1w , ∠H 2w , ∠H 3w 、、∠H 4w Calculate the tangent value T of the solar altitude angle corresponding to all the above line segments, which are T 1a 、T 1b 、T 1c 、T 1w …T 3a 、T 3b 、T 3c 、T 4w Note: There is only one altitude angle corresponding to each line segment within the calculation range (because the azimuth angle is determined during the daytime on the winter solstice, the altitude angle is a unique value).

[0048] Step 7: The height of each blocking building (B1, B2, B3) is H, and the distance between the blocking building (B1, B2, B3...) and the measured building (B0) is L (i.e., the length of each line segment). Calculate the ratio S of H to L. The height of the blocking building (H1, H2, H3) in the blocking area is proportional to the length of the corresponding boundary line segment (L 1a , L 1b , L 2a , L 2b , L 3a , L 3b ), the length of the bisector of the occlusion area angle (L 1c , L 2c , L 3c ) ratio (S 1a 、S 1b 、S 1c ...), taking the blocking building B1 as an example, they are S 1a =H1 / L 1a 、S 1b =H1 / L 1b 、S 1c =H1 / L 1c Since there are no buildings in the unobstructed area, that is, the building height H is 0, the S values of the three line segments in the unobstructed area are all recorded as S w = 0. Note: There are two S values for the boundary line segments within the calculation range, which have different meanings. The S value of the unblocked area indicates that there are no buildings in the area, and the S value of the blocked area indicates that there are blocking buildings in the area.

[0049] Step 8: Calculate the difference C between the tangent value T of the solar altitude angle corresponding to all line segments and the above ratio S. The difference C corresponding to each line segment in the first shading area 1a =T 1a -S 1a 、C 1b =T 1b -S 1b 、C 1c =T 1c -S 1c The difference between the line segments in the first unobstructed area: C 1x =0-S w = 0 (because the first line segment of the first unblocked area is the sun projection line at sunset, the solar altitude angle is 0, and S w =0), C 1y =T 1b -S w =T 1b 、C 1w =T 1w -S w =T 1w, and so on to calculate the difference between the other blocked and unblocked areas. Note: Similar to the above S value, the difference C of the corresponding boundary segment also has two values.

[0050] Step 9: Read the typical annual meteorological data CSWD for buildings in the area where the building is located to obtain the meteorological data for the winter solstice. Obtain the typical annual meteorological data CSWD for buildings and read the meteorological data for the daytime of the winter solstice in the location (the following meteorological data all refer to the meteorological data for the winter solstice), including: hourly direct solar radiation data I and hourly solar azimuth data Asq, and the two sets of data correspond one to one hourly (see Table 1). According to the read meteorological data, obtain the maximum daytime irradiance I max =912(W / m 2 ).

[0051] Table 1

[0052]

[0053] Step 10: Obtain the direct solar irradiance at the corresponding time of all line segments. In the hourly solar azimuth angle Asq data (step 9), find the azimuth angle value closest to the azimuth angle Asx (step 5) corresponding to each line segment, and record it as the approximate azimuth angle Asj. Since the hourly direct solar irradiance data I (step 9) and the hourly solar azimuth angle Asq are one-to-one corresponding, the direct solar irradiance data Ij at the time corresponding to the approximate azimuth angle Asj can be obtained. For example, the azimuth angle ∠1a of a line segment in step 5 is 135.1°. The approximate value of ∠1a is found in the hourly solar azimuth angle Asq data, which is the solar azimuth angle of 235.1° at 16:00 in the afternoon. The direct solar irradiance corresponding to 16:00 in the afternoon is 659W / m 2 , then record I 1a =659W / m 2 By analogy, we can obtain the solar direct irradiance data Ij corresponding to all line segments, including: I 1a , I 1b , I 1c , I 1w …I 3a , I 3b , I 3c , I 4w .

[0054] Step 11: Calculate the solar direct irradiance data Ij corresponding to all line segments and the maximum direct irradiance during the day I max The ratio IR of (step 9) is used as the weight value of the solar irradiance of each line segment. That is: IR 1a =I 1a / I max IR 1b =I1b / I max IR 1c =I 1c / I max IR 1w =I 1w / I max ….

[0055] Step 12: Multiply the weighted value IR of each line segment (obtained in step 11) by the difference C (obtained in step 8) as the weight, and the weighted value is recorded as F. The first shading area F 1a =IR 1a ·C 1a 、F 1b =IR 1b ·C 1b 、F 1c =IR 1c ·C 1c , The first unobstructed area: F 1x =IR 1x ·C 1x =0, F 1y =IR 1b ·C 1y 、F 1w =IR 1w ·C 1w …and so on.

[0056] Step 13: Calculate the average F value of the occluded area and the unoccluded area after weighting, and record it as V. For example, the average value of the first occluded area is: V z1 =(F 1a +F 1b +F 1c ) / 3, and so on, calculate the average F value V of the three occlusion areas respectively z1 , V z2 、V z3 ; Calculate the average F value of the first unobstructed area: V w1 =(F 1x +F 1y +F 1w ) / 3, and so on, and calculate the average F value of the four occlusion areas: V w1 , V w2 、V w3 、V w4 .

[0057] Step 14: Calculate the weight value X of the angle range of each sector-shaped blocked area and the sector-shaped unblocked area. The weight values of the angle range of each sector-shaped blocked area and the sector-shaped unblocked area are calculated by the ratio of the central angle of each sector (obtained in step 3) to the central angle α of the total calculation range, which are X z1 =β1 / α, Xz2 =β2 / α, X z3 =β3 / α, and X w1 =γ1 / α,X w2 =γ2 / α, X w3 =γ3 / α, X w4 =γ4 / α.

[0058] Step 15: Calculate the final occlusion factor Vof. The average difference between each occluded sector and the unoccluded sector (obtained in step 13) is Vof. z1 、V z2 、V z3 and V w1 、V w2 、V w3 、V w4 Assign each corresponding angle weight X z1 、X z2 、X z3 and X w1 、X w2 、X w3 、X w4 , and calculate the sum to get the final value of the occlusion factor, that is, Vof=V z1 ·X z1 +V z2 ·X z2 +V z3 ·X z3 +V w1 ·X w1 +V w2 ·X w2 +V w3 ·X w3 +V w4 ·X w4 The larger the Vof value, the less the sunlight on the measured building (B0) is affected by shading factors, and the greater its solar energy acquisition potential.

[0059] Step 16: Get the value of the occlusion factor Vof1 of solution 1.

[0060] Step 17: Similarly, the value of the occlusion factor Vof2 of solution 2 can be calculated.

[0061] Step 18: Compare the shading factors Vof1 and Vof2 for Scheme 1 and Scheme 2. If Vof1 > Vof2, then Scheme 1 has a higher solar gain potential for the building being measured; otherwise, Scheme 2 has a higher solar gain potential. If the two are equal, then the solar gain potential is the same, but this is highly unlikely. To improve the solar gain potential of the measured building based on a scheme with a lower shading factor (Vof), first optimize the layout to reduce the shading effect of surrounding buildings on the measured building. To improve the solar gain potential of the measured building based on a scheme with a higher shading factor (Vof), ignore the shading effect of surrounding buildings on the measured building and address other influencing factors.

[0062] Definition of concepts:

[0063] Measured building (B0): The building whose occlusion factor (Vof) needs to be measured.

[0064] Blocking buildings (B1, B2, B3...): Within the calculation range (calculation range determined in step 2), there may be other single buildings or building groups around that block the solar radiation that the measured building should receive.

[0065] Calculation point A: The center point of the intersection line between the base outline of the building (B0) and the south facade is used as the calculation point A (attached Figure 2 ).

[0066] Solar altitude angle: the angle between the direct sunlight and the plane where the measurement point A is located at a certain moment.

[0067] Azimuth: The angle between the projection line of direct sunlight on the horizon and the north direction on the horizon (clockwise).

[0068] The building obscuration factor (Vof) is defined as the degree to which a building's solar radiation is obscured by surrounding buildings during the period between sunrise and sunset. Specifically, Vof is the weighted average of the ratio of the obstructing building's height to the distance between the obstructing building and the measured building, and the difference between the tangent of the solar altitude at the corresponding azimuth, at a selected solar position.

[0069] Given that the lower the solar altitude angle, the greater the possibility of buildings blocking each other's sunlight, which is less conducive to solar energy acquisition, this embodiment specifically selects the period with the lowest solar altitude angle (winter solstice), which is also the most unfavorable period for sunlight acquisition, for measurement to characterize the building's solar energy acquisition potential.

[0070] This embodiment first calculates the solar azimuth angle at sunrise and sunset on the winter solstice where the building is located, forming a fan-shaped calculation range from sunrise to sunset, and divides the calculation range into multiple blocked areas and unblocked areas, as well as multiple calculation line segments L (each area has 3 line segments), each of which corresponds to the solar azimuth angle and solar altitude angle at a certain moment. On this basis, two values are mainly calculated, one is the tangent value T of the solar altitude angle corresponding to each line segment, and the other is the ratio S of the height of the blocking building to the distance between the blocking building and the measured building. The difference C is obtained by subtracting the T value from the S value (the former minus the latter). A positive difference C indicates no blocking, and a negative difference indicates blocking. The larger the difference, the less the measured building is blocked by the blocked building, and vice versa (see Appendix). Figure 1 ). At the same time, the approximate direct solar irradiance at the corresponding moment of each calculation line segment is obtained through the CSWD meteorological data of a typical meteorological year for the local building. The irradiance is assigned as a weight to the difference C to obtain the F value. The higher the irradiance, the greater the weight of the difference C, which means that the quality of solar energy at this azimuth is higher and the more it should be obtained by the building. Incorporating the quality of solar energy at different times into the calculation is more scientific and accurate than the traditional building "sunshine hours" method. The F values corresponding to the line segments in the blocked and unblocked areas are averaged to obtain the average difference V of each area. Because the area sizes of each area are different, its size is expressed as the ratio X of the central angle of the sector of each area to the central angle of the sector of the total calculation range. The average difference V of each area is multiplied by the proportion X of the central angle of each area, and the product of each area is summed to obtain the final shading factor value Vof.

[0071] The larger the Vof value, the less the solar energy acquisition potential of the measured building is affected by the shading of surrounding buildings, and the greater its solar energy acquisition potential; conversely, the greater the impact.

[0072] The solar energy harvesting potential of a single building is affected by a variety of factors. This embodiment, by calculating building shading factors, can quantitatively compare the differences in how specific buildings are affected by inter-building shading factors within different building cluster layouts, given the same site area and the same floor area ratio. This, in turn, allows for comparison of differences in solar energy harvesting potential. This provides a reference for optimizing the layout of the building cluster within which a specific building resides during the early stages of design. This embodiment can be used to compare, select, and optimize different building cluster layouts from the perspective of solar energy harvesting potential, and can also be used to assess the solar energy utilization potential of specific buildings within an existing building cluster.

[0073] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for calculating a building solar energy acquisition potential index, characterized in that: The following steps are involved: Obtain the solar azimuth and solar altitude angles corresponding to the sunrise and sunset times to form a fan-shaped calculation range, and obtain a number of calculation line segments within the fan-shaped calculation range; Obtaining the tangent value of the solar altitude angle at the corresponding moment of the calculation line segment, the ratio of the height of the blocking building to the distance between the blocking building and the building to be measured, and subtracting the tangent value of the solar altitude angle from the ratio to obtain a difference; Obtaining the approximate direct solar irradiance at the time corresponding to the calculation line segment, and assigning the approximate direct solar irradiance as a weight to the difference to obtain a weighted value; Obtaining a central angle ratio of the area to be measured, and obtaining a building occlusion factor value of the building to be measured based on the central angle ratio and the weighted value; The process of obtaining the fan-shaped calculation range includes obtaining the center point of the intersection line of the base outline of the building to be measured and the south facade as a measurement point, and drawing the projection line of the sun's rays corresponding to the sunrise and sunset times on the ground plane with the measurement point as the center of the circle based on the solar azimuth corresponding to the sunrise and sunset times to obtain the fan-shaped calculation range; The process of obtaining the plurality of calculation line segments includes rotating the radius line segment of the calculation range clockwise with the measurement point as the center point to obtain a unique intersection point between the radius line segment and the obstructing building; Connecting the measurement points and the unique intersection point to obtain a plurality of boundary line segments, and simultaneously obtaining a plurality of blocked areas and unblocked areas; Obtaining the angle bisector segments of the blocked area and the unblocked area; the plurality of boundary segments, the plurality of angle bisector segments, the sunrise projection line, and the sunset projection line are calculation segments within the calculation range; The process of obtaining the value of the building occlusion factor of the building to be measured includes assigning weight values of the corresponding angle ranges to the average values of the weighted values corresponding to the occluded area and the unoccluded area, and performing summation processing to obtain the value of the building occlusion factor of the building to be measured; The process of obtaining the average value of the weighted values corresponding to the occluded area and the unoccluded area includes obtaining the weighted values of the corresponding calculation segments in the occluded area and the unoccluded area, and the average value of the weighted values of the corresponding calculation segments is the average value of the weighted values corresponding to the occluded area and the unoccluded area; The process of obtaining the weight values of the angular ranges of the occluded area and the unoccluded area includes obtaining the weight values of the angular ranges of the occluded area and the unoccluded area based on the ratio of the central angles corresponding to the occluded area and the unoccluded area to the fan calculation range.

2. The calculation method of the building solar energy acquisition potential index according to claim 1 is characterized in that: If the difference is a positive number, there is no occlusion on the building to be measured; if the difference is a negative number, there is occlusion on the building to be measured.

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