A simplified calculation method for the surface reflectivity of non-metallic materials and its application

Abstract

The application provides a simplified calculation method and application of reflectivity of a non-metal material surface, and the simplified calculation method specifically comprises the following steps: S1, calculating directional-spectrum reflectivity; S2, when the incident medium is air, the air-side refractive index is 1, and the refraction angle χ is calculated; S3, the reflectivity is divided into three regions, wherein the region I is a region where the incident angle is less than 1 rad, the region II is a region where the incident angle is greater than 1 rad and the refractive index is in the interval (1, 5.5], and the region III is a region where the incident angle is greater than 1 rad and the refractive index is in the interval (5.5, 20]; and S4, according to different regions, the reflectivity of the material surface under different incident angles is calculated, wherein the reflectivity calculation formula of the region I is ρ = 0.82 - 1.02 * 0.82 n , the reflectivity calculation formula of the region II is ρ = a + bI c , and the reflectivity calculation formula of the region III is

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material reflectivity, and particularly relates to a simplified calculation method of surface reflectivity of non-metallic material and application. BACKGROUND

[0002] Radiation parameters mainly refer to reflectivity, absorptivity and transmissivity, which come from the surface of a material and reflect the correlation between the surface and the radiation process. In fact, the radiation transfer of the surface is a complex process, and most of the obtained surface characteristic parameters are average values at a certain temperature. The average radiation characteristics are obtained by measuring all directions, all wavelengths or all directions and all wavelengths at the same time. When discussing the surface characteristic parameters, the most basic non-average characteristics are discussed first, and then the average values are obtained by integration: if the wavelength is averaged, the directional total radiation parameter is obtained; if the solid angle direction is averaged, the hemispherical radiation parameter is obtained; if the wavelength and the solid angle (direction) are integrated at the same time, the hemispherical total radiation parameter, i.e. the average radiation parameter in the common sense, is obtained.

[0003] The surface reflectivity is a key parameter considering the radiation transfer process. Due to the complex characteristics of radiation calculation, the diffuse gray body assumption is usually used in engineering to simplify the calculation process. However, in fact, when studying the relationship between the surface of an object and solar radiation, most objects will show strong selectivity in absorbing visible light, which makes the gray body assumption unable to correctly describe the radiation process in this waveband. In addition, for the case of large-angle incidence, the existing normal reflectivity deviates from the actual situation. Therefore, the comprehensive effect of radiation wavelength and direction directly determines the determination of the surface reflectivity and other radiation parameters in the calculation of radiation heat transfer.

[0004] For the discussion of the radiation wavelength, a spectrophotometer is a common method to obtain the surface reflectivity. By selecting different types of spectrophotometers, the required radiation wavelength can be constructed, and then the reflectivity in this waveband can be measured. However, for solids, especially non-metallic materials, it is difficult to construct a mirror reflection surface due to the influence of the material properties of the sample itself, which makes the entire measurement method become cumbersome and it is difficult to obtain the required measurement results. For the discussion of the radiation angle, the data currently used generally follows the standard measurement method of normal incidence, and the surface reflectivity obtained is generally defined as the normal value or the hemispherical total integral value. Existing literature indicates that when the surface is metal, smooth and rough, the hemispherical emissivity is 1.2, 0.95 and 0.98 times the normal emissivity. However, if the incident angle is too large, or the same parameter is used in the calculation process of different wavebands, there will be certain errors, and the fundamental reason is that the wavelength and angle limits in the integral definition of the parameter are different, which overestimates or underestimates the entire calculation result. Therefore, the radiation characteristics of the actual surface should comprehensively consider the dual influence of the radiation wavelength and the radiation direction.

[0005] To analyze the effect of wavelength on reflectivity, a spectral band model is often used. This involves combining the material's spectral curve for a particular band to calculate the reflectivity of the entire band or a specific band. The spectral band approximation divides the object's reflectivity into a finite number of spectral bands based on the full-band radiation range. The spectral radiation characteristics within each spectral band are assumed to be constant, and each spectral band follows the gray-body hypothesis. Therefore, the reflectivity over the entire band can be expressed as follows:

[0006]

[0007] For the jth spectral band interval [λ j ,λ j+1 ] can be expressed by the following formula.

[0008]

[0009] According to the asymptotic property of the integral mean value theorem, the smaller the integral interval value, the closer the position of the median point is to the midpoint of the integral interval, so ξ≈(λ i+1 +λ i ) / 2. Therefore, after obtaining the wavelength range of interest based on the spectral law of the surface material, the reflectivity of a certain spectral band can be estimated using the definite integral mean value theorem or Simpson's formula.

[0010] According to the definition of reflectivity, to obtain hemispherical reflectivity, the solid angle must be integrated, which is determined by both the elevation and azimuth angles. Taking solar radiation as an example, the angular influence on the target surface reflectivity is primarily due to the change in the angle of incidence of the sun upon the target surface. This angle is primarily determined by the solar elevation and the sunwall azimuth. Therefore, determining the solar elevation and sunwall azimuth from the position information of the sun and the target surface is the primary task in calculating solar radiation reflectivity.

[0011] Generally speaking, when the sun radiates onto a surface, the position of the surface determines the sunwall azimuth, which in turn affects the result of the solar incidence angle calculation.

[0012] Figure 22 Schematic diagram of sunlight incident on the surface of a material.

[0013] like Figure 22 As shown in the figure, the general angle relationship of the sun's incidence when the angle between the wall and the horizontal plane is ζ is given. In order to determine the actual radiation incidence angle, the existing calculation method can be used to determine it. n is the solar incidence angle, and γ is the wall azimuth.

[0014] Calculations require first determining the positional relationships between the various surfaces, then determining the angles through geometric relationships. For altitude calculations, the critical value for horizontal planes is the inverse tangent of the half-diagonal length between the obstructing surface and the base; the critical value for vertical planes is the inverse tangent of the half-side length between the obstructing surface and the base. For sunwall azimuth calculations, first determine the obstructing surface azimuth and the solar azimuth, then calculate the difference between the two.

[0015] After determining the critical angle of the target surface at each location in the hemispherical space, it is assumed that the surface reflectivity is the same in each solid angle space, and the solution can be found according to the idea of ​​the integral mean value theorem, that is, for any solid angle There is a median point Satisfies the following formula, where

[0016]

[0017] In summary, from the perspective of the integral definition, the influence of radiation wavelength and direction on reflectivity includes not only the dynamic changes in the angle of incidence caused by the changing position of the sun, but also the spatial variations in the angle of incidence caused by different surface positions. Given the reflectivity under certain conditions in the parameter table, the integral method can be used to obtain the reflectivity under other conditions. However, in practice, the integral method cannot obtain a complete set of input parameters due to conditional constraints, which makes it inconvenient in actual use. Therefore, the current technical problem to be solved is how to simplify the reflectivity calculation method for non-metallic materials. Summary of the Invention

[0018] The present invention is made to solve the above problems, and its purpose is to provide a simplified calculation method and application of the surface reflectivity of non-metallic materials.

[0019] The present invention provides a simplified calculation method for the surface reflectivity of a non-metallic material, which has the following characteristics: the material includes a non-metallic material and a metallic material. When the material is a non-metallic material, the simplified calculation method specifically includes the following steps:

[0020] S1, calculate the directional-spectral reflectance by formula (1), (1)

[0021] Where i n is the incident angle; S2, when the incident medium is air, the refractive index of the air side is 1, and the refractive angle χ can be obtained by formula (2), (2) Where i nis the incident angle, n is the equivalent refractive index of the material when the wavelength is λ; S3, the reflectivity is divided into three regions, where the incident angle is less than 1 rad as region I, the incident angle is greater than 1 rad and the refractive index is in the interval (1, 5.5] as region II, and the incident angle is greater than 1 rad and the refractive index is in the interval (5.5, 20] as region III; and S4, according to different regions, calculate the reflectivity of the material surface at different incident angles, where the reflectivity calculation formula of region I is ρ = 0.82-1.02×0.82 n , the reflectivity calculation formula of zone II is ρ=a+bI c , the reflectivity calculation formula of zone III is: where i cr =1.52-1.19×0.72 n , where i n represents the incident angle, ρ represents the reflectivity, i cr Indicates the extreme point of the reflectivity curve.

[0022] The simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention may also have the following characteristics: the reflectivity curve of zone I remains basically unchanged, and within zone I, the reflectivity is independent of the incident angle and is mainly affected by the equivalent refractive index of the material.

[0023] The simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention may also have the following characteristics: the reflectivity curve of zone II increases monotonically within the definition domain, and an inflection point appears when the incident angle is between 1.0 and 1.4 rad. As the equivalent refractive index continues to increase, the inflection point gradually shifts to the right.

[0024] The simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention may also have the following characteristics: the reflectivity curve of zone III first decreases and then increases within the definition domain, and a minimum point appears at 1.3 rad, and then rises sharply. As the equivalent refractive index continues to increase, the minimum point continues to move to the right, changing in an exponential function relationship.

[0025] The simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention may also have the following characteristics: when the surface of the material is opaque, its transmittance is 0, and the calculation formula of the directional-spectral absorptivity is α' λ (λ,i n )=1-ρ' λ (λ,i n ), where α' is the absorptivity, λ is the wavelength, i n is the incident angle, and ρ' is the reflectivity.

[0026] The simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention may also have the following characteristics: wherein the calculation formula for the directional-spectral transmittance of the surface transparent material is: Where D is the thickness of the transparent surface, K is the extinction coefficient, τ' is the transmittance, λ is the wavelength, i n is the angle of incidence.

[0027] The simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention may also have the following characteristics: wherein the calculation formula for the spectral-directional absorptivity of the surface transparent material is α' λ (λ,i n )=1-ρ' λ (λ,i n )-τ' λ (λ,i n ), where λ is the wavelength, τ' is the transmittance, ρ' is the reflectance, i n is the incident angle, and α' is the absorptivity.

[0028] The present invention also provides an application of a simplified calculation method for the surface reflectivity of non-metallic materials in the calculation of the reflectivity of surface materials in a radiation environment of a building complex.

[0029] The simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention can be used in the calculation of the reflectivity of surface materials in the radiation environment of a building complex. The method can also have the following features: meteorological parameters are introduced into the Grasshopper platform, the Ladybug plug-in is used to obtain the sun position information at the target time point, and the incident angle of a certain surface of the building complex is determined, and the reflectivity of the surface material is calculated using the simplified calculation method for the surface reflectivity of non-metallic materials.

[0030] Functions and effects of the invention

[0031] According to the simplified calculation method and application of the surface reflectivity of non-metallic materials involved in the present invention, the present invention adopts a partition calculation method, and the fitting goodness of fit is greater than 0.98. While ensuring the calculation accuracy, it simplifies the calculation process of trigonometric functions and multivariable relationships in the definition formula, clarifies the applicable conditions of the calculation method, avoids the occurrence of overfitting, solves the problem of difficulty in obtaining unknown variables in the definition method, avoids the inconvenience and tedious work of laboratory measurement, and saves time and effort.

[0032] The present invention is mainly applicable to non-metallic surfaces and all situations where their equivalent refractive index is in the range of (1, 20), basically covering the requirements of general surface materials, especially when the incident angle is less than 1 rad, which is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1is a reflectivity curve when n ranges from 1 to 20 in an embodiment of the present invention;

[0034] Figure 2 is a reflectivity curve when n ranges from 1 to 5.5 in an embodiment of the present invention;

[0035] Figure 3 is a reflectivity curve when n ranges from 5.5 to 20 in an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of zone I in the reflectivity partition of the surface material in an embodiment of the present invention;

[0037] Figure 5 is a graph of the refractive index and reflectivity of Region I in an embodiment of the present invention;

[0038] Figure 6 Schematic diagram of zone II and zone III in the reflectivity partitioning of the surface material in an embodiment of the present invention;

[0039] Figure 7 is a graph of the refractive index and reflectivity of Region II in an embodiment of the present invention;

[0040] Figure 8 is a graph of the refractive index and reflectivity of Region III in an embodiment of the present invention;

[0041] Figure 9 is the correlation curve between reflectivity and time in a brick paved road;

[0042] Figure 10 is the correlation curve between reflectivity and time in asphalt pavement;

[0043] Figure 11 is the correlation curve between reflectivity and time in wooden pavement;

[0044] Figure 12 are the mean relative error (MRE) and root mean square error (RMSE) between the calculated reflectance and the measured values ​​for brick pavement, asphalt pavement, and wooden pavement;

[0045] Figure 13 It is the direct sunlight condition in the building complex at 7:00 in summer;

[0046] Figure 14 It is the direct sunlight condition in the building complex at 7:00 in winter;

[0047] Figure 15 It is a schematic diagram of the distribution of incident angles on the building surface;

[0048] Figure 16 This is a diagram of how light in a relatively sparse building complex first reflects off the ground and then reflects off the surfaces of surrounding buildings.

[0049] Figure 17 is a schematic diagram of direct re-reflection of light to the surrounding building surface in a more dense building group;

[0050] Figure 18 is a schematic diagram of light incident to a diffuse surface at a small angle, and a large-angle incident to the surrounding surface appears in the reflected light cluster;

[0051] Figure 19 is a basic composition flowchart of the building relationship calculation platform;

[0052] Figure 20 is a screenshot of the method of introducing meteorological parameters into the Grasshopper platform and using the Ladybug plug-in to determine the incident angle;

[0053] Figure 21 is a screenshot of the surface material reflectivity calculated by the surface material reflectivity calculation program required by the environmental calculation module; and

[0054] Figure 22 is a schematic diagram of the sun incident to the material surface. DETAILED DESCRIPTION

[0055] In order to make the technical means, creative features, purposes and effects realized by the present application easy to understand, the following embodiments will be specifically described in combination with the drawings.

[0056] Figure 1 is the reflectivity curve of n from 1 to 20 in the embodiment of the present application. Figure 2 is the reflectivity curve of n from 1 to 5.5 in the embodiment of the present application. Figure 3 is the reflectivity curve of n from 5.5 to 20 in the embodiment of the present application.

[0057] As shown in Figure 1 , the material in the embodiment includes non-metallic materials and metal materials, and when the material is a non-metallic material, the simplified calculation method specifically includes the following steps:

[0058] S1, calculate the directional-spectral reflectivity by formula (1).

[0059] (1)

[0060] In the formula, i n is the incident angle.

[0061] The present application considers that each small incident surface on the surface of the non-metallic material is approximately smooth, that is, the reflection generated on the surface is specular reflection, and that all transparent structures are uncoated and film-coated.

[0062] S2, when the incident medium is air, the air-side refractive index is 1, and the refraction angle χ can be obtained by formula (2).

[0063] (2)

[0064] In the formula, i n is the incident angle, and n is the equivalent refractive index of the material at a wavelength λ.

[0065] The surface material is often a composite system and is not a pure substance, so the refractive index here is the equivalent refractive index of the surface composite material, which shows the deflection of the radiation wave formed after the light is incident on the surface, and the value can also be obtained by converting the normal emissivity in the commonly used data table.

[0066] The reflectivity of a non-metal surface is a function of the incident angle and the equivalent refractive index, and the equivalent refractive index is the ratio of the wavelengths of the two media, that is, a function of the wavelength, so it can be considered that the calculation result of the reflectivity is affected by the wavelength and the direction. In the actual radiation process, the incident angle is usually greater than the refraction angle, that is, the equivalent refractive index is in the interval (1, +∞), and the incident angle is in the interval (0, π / 2).

[0067] As shown in Figures 1-3 , the calculation results of the reflectivity under different incident angles (0, π / 2) and different equivalent refractive indices (1, 20] are plotted.

[0068] S3, the reflectivity is divided into three regions, wherein the incident angle less than 1 rad is region I, the incident angle greater than 1 rad and the refractive index in the interval (1, 5.5] is region II, and the incident angle greater than 1 rad and the refractive index in the interval (5.5, 20] is region III.

[0069] Figure 4 is a schematic diagram of region I in the reflectivity partition of the surface material in the embodiment of the application. Figure 5 is a curve graph of the refractive index and the reflectivity in region I in the embodiment of the application. Figure 6 is a schematic diagram of region II and region III in the reflectivity partition of the surface material in the embodiment of the application. Figure 7 is a curve graph of the refractive index and the reflectivity in region II in the embodiment of the application. Figure 8 is a curve graph of the refractive index and the reflectivity in region III in the embodiment of the application.

[0070] Specifically, as shown in Figures 4-8 , in the target interval, the reflectivity curve gradually increases from bottom to top with the equivalent refractive index.

[0071] Region I is an angle-independent region, n∈(1, 20], i n ∈(0, 1].

[0072] The reflectivity curve of region I is basically unchanged, and in region I, the reflectivity is independent of the incident angle and is mainly affected by the equivalent refractive index of the material.

[0073] When the incident angle is greater than 1.0 rad, the reflectivity curve changes in two different ways due to the difference in the equivalent refractive index.

[0074] The reflectivity calculation formula of region I is ρ = 0.82 - 1.02 x 0.82 n .

[0075] Region II is a monotonically increasing region, n ∈ (1, 5.5], i n ∈ (1, 1.57].

[0076] The equivalent refractive index of region II is in the interval (1, 5.5), and the reflectivity curve is monotonically increasing in the domain, and has an inflection point between incident angles of 1.0-1.4 rad, and the inflection point gradually moves to the right as the equivalent refractive index increases.

[0077] The reflectivity calculation formula of region II is ρ = a + bI c .

[0078] Wherein, the values of a, b, c, n are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] Region III is a piecewise function region, n ∈ (5.5, 20], i n ∈ (1, 1.57].

[0083] The equivalent refractive index of region III is in the interval (5.5, 20], and the reflectivity curve first decreases and then increases in the domain, and has a minimum point starting from 1.3 rad, and then rises sharply, and as the equivalent refractive index increases, the minimum point moves to the right, showing an exponential function relationship.

[0084] The reflectivity calculation formula of region III is Wherein i cr = 1.52 - 1.19 x 0.72 n .

[0085] In the formula, i n represents the incident angle, ρ represents the reflectivity, and i cr represents the extreme point of the reflectivity curve.

[0086] Wherein, the values of a1, b1, c1, n, a2, b2, c2 are shown in Table 2.

[0087] Table 2

[0088] n [a1] [b1] ​ n [a2] [b2] [ca2] 5.6 0.57 -0.17 1.14 5.6 0.43 0.56 30.73 5.8 0.58 -0.18 1.24 5.8 0.43 0.56 32.08 6.0 0.56 -0.16 1.89 6.0 0.44 0.55 33.61 6.2 0.58 -0.17 1.84 6.2 0.44 0.55 34.89 6.4 0.57 -0.17 2.34 6.4 0.44 0.55 36.44 6.6 0.59 -0.19 2.20 6.6 0.44 0.54 37.61 6.8 0.59 -0.19 2.61 6.8 0.45 0.54 39.16 7.0 0.61 -0.20 2.39 7.0 0.45 0.54 40.23 8.0 0.61 -0.24 2.33 8.0 0.46 0.53 47.30 9.0 0.68 -0.27 3.25 9.0 0.46 0.52 52.69 10.0 0.70 -0.29 3.50 10.0 0.47 0.52 59.01 11.0 0.71 -0.31 4.38 11.0 0.47 0.51 66.49 12.0 0.74 -0.33 4.31 12.0 0.47 0.51 71.67 13.0 0.74 -0.34 5.00 13.0 0.48 0.51 79.28 14.0 0.75 -0.36 5.59 14.0 0.48 0.51 87.58 15.0 0.76 -0.38 6.10 15.0 0.48 0.51 96.74 16.0 0.77 -0.39 6.55 16.0 0.49 0.52 107.04 17.0 0.79 -0.38 6.24 17.0 0.49 0.53 118.83 18.0 0.80 -0.40 6.69 18.0 0.49 0.54 132.67 19.0 0.80 -0.41 7.10 19.0 0.50 0.57 149.46 20.0 0.81 -0.42 7.49 20.0 0.50 0.61 170.84

[0089] where I is a dimensionless incident angle, which is the ratio of the actual incident angle to the interval length π / 2, i.e. I = 2i / π n For the equivalent refractive index not in the table but in the interval, the corresponding reflectivity value can be obtained by using the difference method.

[0090] The method verification of the above calculation method is as follows:

[0091] Taking the solar radiation problem as an example, the surface material reflectivity obtained by the actual measurement result and the reflectivity obtained by the present application are compared, and the correlation curve between the reflectivity of each surface material and the time is drawn, so as to verify the effectiveness of the surface material reflectivity partition calculation method. The incident angle in the partition calculation method is consistent with the solar information corresponding to the actual measurement time, and the data of various materials come from the radiation parameters in the "Urban Residential District Thermal Environment Design Standard (JGJ 286-2013)", and then the equivalent refractive index is calculated by formula (2), and finally the reflectivity of various materials is obtained.

[0092] The average relative error (MRE) and the root mean square error (RMSE) are selected to compare the results of the proposed calculation method with the actual measurement results. The average relative error reflects the credibility of the calculation method, and the root mean square error is used to judge the deviation degree of the calculation method and the actual measurement results.

[0093] Figure 9 is the correlation curve between the reflectivity and the time in the brick paving road. Figure 10 is the correlation curve between the reflectivity and the time in the asphalt road. Figure 11 is the correlation curve between the reflectivity and the time in the wooden road. Figure 12 is the average relative error (MRE) and the root mean square error (RMSE) of the reflectivity calculated by the brick paving road, the asphalt road and the wooden road and the actual measurement results.

[0094] As shown in Figures 9-12 , the comparison of the calculation results and the actual measurement results can be seen from Figures 9-12 , the average relative error of the calculation method and the actual measurement results is within 20%, and the root mean square error is within 0.1.

[0095] It can be seen that the partition calculation method proposed in the present application considers the influence of the change of the solar incident angle of different material building surfaces on the surface material reflectivity, which is helpful to improve the accuracy of the radiation parameter calculation.

[0096] The simplified calculation method of the non-metal material surface reflectivity of the application plays an important role in the calculation process of the radiation environment of the building group. The existing surface material reflectivity generally follows the standard measurement method of normal incidence, and its applicable range is generally less than 1 rad (about 57°) of incidence condition. However, no matter single building or building group, the incidence angle of the sun will exceed 1 rad, resulting in a large difference between the existing normal reflectivity and the actual reflectivity.

[0097] Figure 13 is the direct sunlight of the building group at 7:00 in summer. Figure 14 is the direct sunlight of the building group at 7:00 in winter. Figure 15 is a schematic diagram of the incidence angle distribution of the building surface.

[0098] As shown in Figures 13-15 , taking a "nine-square" building group arranged in a positive direction in Shanghai as an example, the direct sunlight of the south-facing, east-facing and west-facing surfaces of the building group under the condition of strong solar radiation in the daytime of the typical meteorological year in four seasons is calculated respectively.

[0099] As shown in Figure 15 , the incidence angle distribution of the central building of the "nine-square" building group model in the direct sunlight period is given, and the red part represents the proportion of time with incidence angle greater than 1 rad, and the red number is marked.

[0100] It can be seen that the proportion of time with incidence angle greater than 1 rad is between 0-50% in different seasons because of the different azimuths of the day wall, and the east-facing surface is mainly distributed in the first 1-3 hours of sunrise; the west-facing surface is opposite to the east-facing surface. The phenomenon of large-angle incidence of solar radiation (incidence angle greater than 1 rad) is different due to the different seasons, and even under the shielding condition of the building group, the proportion is still relatively high, so the influence of incidence angle on the reflectivity of the building surface cannot be ignored.

[0101] In addition, after the incidence of the sun, due to the shielding of the building group and the existence of multiple reflections, the building surface may still appear large-angle phenomenon after reflection and re-incident on the surrounding building surface, and this process is related to the roughness of the surface, the height of the building and the spatial position between the buildings.

[0102] Figure 16 is a schematic diagram of light first reflecting to the ground and then reflecting to the surrounding building surface in a relatively sparse building group. Figure 17 is a schematic diagram of light directly reflecting to the surrounding building surface in a relatively dense building group. Figure 18 is a schematic diagram of light incident to a diffuse surface at a small angle, and the reflected light cluster appears large-angle incidence to the surrounding surface.

[0103] As shown in Figures 16-18 There are three cases: the first is that the light is incident on the building surface at a large angle, then reflected to the ground and then reflected to the surrounding building surface again, which generally occurs in a relatively sparse building group; the second is that the light is incident on the building surface at a large angle, and is directly reflected to the surrounding building surface again, which generally occurs in a relatively dense building group; and the third is that the light is incident on the diffuse surface at a small angle, and the reflected light cluster is incident on the surrounding surface at a large angle.

[0104] For the above-mentioned needs, the present application can be well solved, which makes up for the present situation that the calculation parameters do not meet the requirements, and obtains the key radiation parameters required for radiation environment calculation.

[0105] Figure 19 is a basic composition flowchart of the building relationship calculation platform.

[0106] As shown in Figure 19 The calculation process can be embodied as step 2 of the calculation platform. Note that the independent individuals in the building group can be simply summarized as two types of building bodies and non-building bodies. The various surfaces constituting the building group interface can be divided into three categories according to the radiation properties: the first category is non-transparent surfaces such as walls and floor tiles; the second category is transparent surfaces such as windows and curtain walls; and the third category is porous surfaces such as vegetation. The calculation method of the present application is mainly applicable to the first two types of surfaces, and the calculation method of the third type of surface is already mature.

[0107] After the building space relationship is determined, the calculation steps involved in the present application can be realized through existing programming software. The present application takes the method of combining Grasshopper platform with Python as an example.

[0108] I. Determination of input conditions.

[0109] The influence of radiation wavelength and direction is the key to the calculation of surface material reflectivity. The influence of wavelength is reflected in the equivalent refractive index of the material, and the influence of direction is reflected in the incident angle after the action of the sun on the surface. When the surface material is determined, its equivalent refractive index can be obtained through the relevant physical property parameter table. For the incident angle, it needs to be determined in combination with the surface position and the position state of the sun at the target time point, wherein the position information of the surface can be obtained from the space relationship module, and the position state of the sun can be obtained through conversion of the typical meteorological year.

[0110] Figure 20 is a screenshot of the method of introducing meteorological parameters into the Grasshopper platform and using the Ladybug plug-in to determine the incident angle.

[0111] As shown in Figure 20The meteorological parameters are introduced into the Grasshopper platform, and the Ladybug plug-in is used to obtain the solar position information at a target time point, such as the elevation angle and the azimuth angle, so that the incident angle of a surface of a building group can be determined.

[0112] II. Parameter determination procedure.

[0113] After the input conditions are determined, the surface material reflectivity is calculated by using the present application. Python built in Grasshopper is used as a platform, and a parameter table is embedded therein, and a conditional statement is written to determine the incident angle and the equivalent refractive index, so as to determine the surface material reflectivity calculation formula. The selection structure contains three levels: the first level is the determination of the incident angle, that is, the selection of the radiation I region and the II region; the second level is the determination of the equivalent refractive index, that is, the selection of the radiation II region and the III region; and the third level is the selection of the coefficients of the specific calculation formula.

[0114] Figure 21 is a screenshot of the surface material reflectivity required by the environmental calculation module obtained by the surface material reflectivity calculation procedure.

[0115] As shown in Figure 21 , after the selection procedure, the surface material reflectivity required by the environmental calculation module is finally obtained.

[0116] When the reflectivity is determined, other radiation parameters can be further obtained.

[0117] When the surface is opaque, its transmittance is 0, and the directional-spectral absorptance can be calculated.

[0118] The calculation formula of the directional-spectral absorptance is α' λ (λ, i n ) = 1 - ρ' λ (λ, i n ), wherein α' is the absorptance, λ is the wavelength, i n is the incident angle, and ρ' is the reflectivity.

[0119] For a transparent surface, when it is in an ideal state, its absorptance is 0, but in most cases, there is absorptance.

[0120] The calculation formula of the directional-spectral transmittance of the transparent surface material is wherein D is the thickness of the transparent surface, K is the extinction coefficient, τ' is the transmittance, λ is the wavelength, and i n is the incident angle.

[0121] The calculation formula of the spectral-directional absorptance of the transparent surface material is α' λ (λ, i n ) = 1 - ρ' λ(λ,i n )-τ' λ (λ,i n ), where λ is the wavelength, τ' is the transmittance, ρ' is the reflectance, i n is the incident angle, α' is the absorptivity

[0122] For metal materials, the essential difference lies in the different attenuation coefficients κ of the materials. Non-metallic materials are generally considered to have κ≈0, while the κ of metals cannot be ignored.

[0123] When calculating the directional-spectral reflectance of this type of material, it is necessary to replace formula (1) with Then, deduction and calculation are performed according to the calculation method proposed by the present invention.

[0124] Functions and Effects of the Embodiments

[0125] According to the simplified calculation method and application of the surface reflectivity of non-metallic materials involved in the present invention, the present invention adopts a partition calculation method, and the fitting goodness of fit is greater than 0.98. While ensuring the calculation accuracy, it simplifies the calculation process of trigonometric functions and multivariable relationships in the definition formula, clarifies the applicable conditions of the calculation method, avoids the occurrence of overfitting, solves the problem of difficulty in obtaining unknown variables in the definition method, avoids the inconvenience and tedious work of laboratory measurement, and saves time and effort.

[0126] The present invention is mainly applicable to non-metallic surfaces and all situations where their equivalent refractive index is in the range of (1, 20), basically covering the requirements of general surface materials, especially when the incident angle is less than 1 rad, which is more convenient.

[0127] The calculation method of the present invention is also equipped with an accessible fitting relationship table, which can be used directly for relevant numerical values, thereby greatly improving practicality.

[0128] According to the present invention, other radiation parameters can be further obtained, including the directional-spectral absorptivity of opaque surfaces, the extinction coefficient and spectral-directional absorptivity of transparent surfaces, and the calculation of the directional-spectral reflectivity of metal materials.

[0129] The present invention can be applied to opaque surfaces in building complex interfaces, such as walls and floor tiles, as well as transparent surfaces such as windows and curtain walls. Compared with the standard measurement method that follows normal incidence, the reflectivity can still be kept close to the actual reflectivity under large-angle incidence conditions exceeding 1 rad, and has higher accuracy.

[0130] The present invention takes into account the influence of changes in the solar incident angle on the reflectivity of the surface material of buildings made of different materials, which helps to improve the accuracy of radiation parameter calculation.

[0131] Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A simplified calculation method for the surface reflectivity of non-metallic materials, characterized in that: The simplified calculation method specifically includes the following steps: S1, calculate the directional-spectral reflectance by formula (1), (1) Where i n is the angle of incidence; S2, when the incident medium is air, the refractive index on the air side is 1, and the refraction angle χ can be calculated by formula (2): (2) Where i n is the incident angle, n is the equivalent refractive index of the material when the wavelength is λ; S3, the reflectivity is divided into three regions, wherein the incident angle is less than 1 rad and the refractive index is in the interval (1, 20] as region I, the incident angle is greater than 1 rad and the refractive index is in the interval (1, 5.5] as region II, and the incident angle is greater than 1 rad and the refractive index is in the interval (5.5, 20] as region III; and S4, calculate the reflectivity of the material surface at different incident angles according to different regions, where the reflectivity calculation formula of region I is ρ = 0.82-1.02×0.82 n The reflectivity calculation formula of the II zone is ρ=a+bI c The reflectivity calculation formula of zone III is: where i cr =1.52-1.19×0.72 n , where i n represents the incident angle, ρ represents the reflectivity, i cr Indicates the extreme point of the reflectivity curve.

2. The simplified calculation method for the surface reflectivity of non-metallic materials according to claim 1, characterized in that: in, The reflectivity curve of region I remains substantially unchanged. In region I, the reflectivity has nothing to do with the incident angle and is mainly affected by the equivalent refractive index of the material.

3. The simplified calculation method for the surface reflectivity of non-metallic materials according to claim 1, characterized in that: in, The reflectivity curve of zone II increases monotonically within the definition domain, and has an inflection point between incident angles of 1.0-1.4 rad. As the equivalent refractive index increases, the inflection point gradually shifts to the right.

4. The simplified calculation method for the surface reflectivity of non-metallic materials according to claim 1, characterized in that: in, The reflectivity curve of zone III first decreases and then increases within the definition domain, and a minimum point appears at 1.3 rad, and then rises sharply. As the equivalent refractive index continues to increase, the minimum point continues to move to the right, changing in an exponential function relationship.

5. An application of the simplified calculation method for the surface reflectivity of non-metallic materials as claimed in claim 1 in the calculation of the directional-spectral absorptivity of surface opaque materials, characterized in that: When the material surface is opaque, its transmittance is 0, and the calculation formula of the directional-spectral absorptivity is α' λ (λ,i n )=1-ρ' λ (λ,i n ), where α' is the absorptivity, λ is the wavelength, i n is the incident angle, and ρ' is the reflectivity.

6. An application of the simplified calculation method for the surface reflectivity of a non-metallic material as claimed in claim 1 in the calculation of the directional-spectral transmittance of a surface transparent material, characterized in that: The calculation formula of the directional-spectral transmittance of the surface transparent material is: Where D is the thickness of the transparent surface, K is the extinction coefficient, τ is the transmittance, λ' is the wavelength, i n is the angle of incidence.

7. An application of the simplified calculation method for the surface reflectivity of a non-metallic material as claimed in claim 1 in the calculation of the spectral-directional absorptivity of a surface transparent material, characterized in that: The calculation formula of the spectral-directional absorptivity of the surface transparent material is α' λ (λ,i n )=1-ρ' λ (λ,i n )-τ' λ (λ,i n ), where λ is the wavelength, τ' is the transmittance, ρ' is the reflectance, i n is the incident angle, and α' is the absorptivity.

8. Application of the simplified calculation method for the surface reflectivity of non-metallic materials as claimed in claims 1 to 7 in the calculation of the reflectivity of surface materials in a radiation environment of a building complex.

9. An application of the simplified calculation method for the surface reflectivity of non-metallic materials as claimed in claim 8 in the calculation of the reflectivity of surface materials in a building complex radiation environment, characterized in that: Meteorological parameters were introduced into the Grasshopper platform, and the Ladybug plug-in was used to obtain the sun position information at the target time point. The incident angle of a certain surface of the building complex was determined, and the reflectivity of the surface material was calculated using a simplified calculation method for the surface reflectivity of non-metallic materials.

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