Simplified calculation method for surface reflectivity of non-metallic material and application

Abstract

The invention provides a simplified calculation method and application of the surface reflectivity of a non-metallic material. The simplified calculation method specifically comprises the following steps: S1, calculating direction-spectral reflectivity; s2, when the incident medium is air, the refractive index of the air side is 1, and the refraction angle x is calculated; s3, the reflectivity is divided into three areas, the area is the area I when the incident angle is smaller than 1rad, the area is the area II when the incident angle is larger than 1rad and the refractive index is within the interval (1, 5.5), and the area is the area III when the incident angle is larger than 1rad and the refractive index is within the interval (5.5, 20); and S4, the reflectivity of the material surface under different incident angles is calculated according to different areas, the reflectivity calculation formula of the I area is rho = 0.82-1.02 * 0.82 n, the reflectivity calculation formula of the II area is rho = a + bIc, and the reflectivity calculation formula of the III area is # imgabs0 #, and the reflectivity calculation formula of the I area is rho = 0.82-1.02 * 0.82 n, the reflectivity calculation formula of the II area is rho = a + bIc.

Description

Technical Field

[0001] The invention relates to the technical field of material reflectivity, and in particular to a simplified calculation method for the surface reflectivity of a non-metallic material and its application. Background Art

[0002] Radiation parameters mainly refer to reflectivity, absorptivity and transmittance, which come from the surface of the material and reflect the correlation between the surface and the radiation process. In fact, the radiation transfer of the surface is a complex process. Most of the surface characteristic parameters obtained are average values ​​at a certain temperature. The average radiation characteristics are measured in all directions, all wavelengths, or all directions and all wavelengths at the same time. When discussing surface characteristic parameters, the most basic non-average characteristics are generally discussed first, and then the average value is 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 solid angle (direction) are integrated at the same time, the hemispherical total radiation parameter can be obtained, which is the average radiation parameter in the common sense.

[0003] Surface reflectivity is a key parameter to consider in the radiation transfer process. Due to the complex characteristics of radiation calculation, in order to simplify the calculation process, the diffuse gray assumption of the surface is a commonly used processing method in engineering. But in fact, when studying the relationship between the surface of an object and solar radiation, most objects will show strong selectivity in the absorption of visible light, which makes the gray body assumption unable to correctly describe the radiation process in this band. In addition, for the case of large angle incidence, the existing normal reflectivity deviates from the actual situation. Therefore, the combined effect of radiation wavelength and direction directly determines the determination of radiation parameters such as surface reflectivity in radiation heat transfer calculations.

[0004] Regarding the discussion of radiation wavelength, spectrophotometer is a common method to obtain surface reflectivity. By selecting different types of spectrophotometers, the required radiation wavelength can be constructed, and then the reflectivity measurement in this band can be realized. However, for solids, due to the influence of the material properties of the sample itself, especially non-metallic materials, it is difficult to construct a mirror reflection surface, which makes the entire measurement method cumbersome and difficult to obtain measurement results that meet the requirements. Regarding the discussion of radiation angle, the data currently used usually follows the standard measurement method of normal incidence, and the surface reflectivity obtained is generally defined as the normal value or the total integral value of the hemisphere. Existing literature points out 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 parameters are used in the calculation process of different bands, there will be certain errors. 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 radiation wavelength and radiation direction.

[0005] In order to analyze the effect of wavelength on reflectivity, the spectral band model is usually used for calculation, that is, combining the spectral curve of a certain band material to calculate the reflectivity of the entire band or a certain band. The spectral band approximation method divides the object reflectivity into a limited number of spectral bands according to the full-band radiation range, and considers the spectral radiation characteristics within each spectral band to be constant, and each spectral band follows the gray body hypothesis. Therefore, the reflectivity over the entire band can be expressed by the following formula:

[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 according to the spectral law of the surface material, the reflectivity of a certain spectral band range can be estimated by using the definite integral mean value theorem or Simpson's formula.

[0010] According to the definition of reflectivity, in order to obtain the hemispherical reflectivity, the solid angle should be integrated, and the solid angle is determined by the altitude angle and the azimuth angle. Taking the solar radiation process as an example, the angular influence of the target surface reflectivity is mainly reflected in the change of the incident angle when the sun shines on the target surface. This angle is mainly determined by the solar altitude angle and the sun wall azimuth angle. Therefore, obtaining the solar altitude angle and the sun wall azimuth angle through the position information of the sun and the target surface is the first task in calculating the 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] Fig. 22 Schematic diagram of the sun incident on the surface of the material.

[0013] like Fig. 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, it can be determined with the help of existing calculation methods. n is the solar incidence angle, and γ is the wall azimuth.

[0014] When calculating, it is necessary to first give the positional relationship between different surfaces, and then determine the angle value through geometric relationships. For the calculation of the altitude angle, the critical value of the horizontal plane is the arc tangent of the half diagonal length of the shielding surface and the bottom surface; the critical value of the vertical plane is the arc tangent of the half side length of the shielding surface and the bottom surface. For the calculation of the sun wall azimuth, first determine the azimuth of the shielding surface and the solar azimuth, and 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 can be solved 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 integral definition, the influence of radiation wavelength and direction on reflectivity includes not only the dynamic change of incident angle caused by the change of sun position, but also the spatial change of incident angle 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 fact, the integral method cannot obtain complete input parameters due to conditional restrictions, which is inconvenient in specific use. Therefore, the technical problem that needs to be solved urgently is how to simplify the reflectivity calculation method applicable to non-metallic materials. Summary of the invention

[0018] The present invention is made to solve the above-mentioned problem, and aims 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 metal 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] In the formula, i n is the incident angle; 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) In the formula, 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, the reflectivity of the material surface at different incident angles is calculated, 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 moves to the right.

[0024] In the simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention, it can 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, and 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 absorbance 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, and 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 invention also provides an application of a simplified calculation method for the surface reflectivity of a non-metallic material in the calculation of the reflectivity of a surface material in a radiation environment of a building complex.

[0029] In the application of the simplified calculation method for the surface reflectivity of non-metallic materials provided by the present invention in the calculation of the reflectivity of surface materials in the radiation environment of a building complex, the following features may also be provided: wherein, 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 by 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 goodness of fit is greater than 0.98. While ensuring the calculation accuracy, the calculation process of trigonometric functions and multivariate relationships in the definition formula is simplified, the applicable conditions of the calculation method are clarified, and the occurrence of overfitting is avoided. The problem that the unknown variables in the definition method are difficult to obtain is solved, the inconvenience and tedious work of laboratory measurement are avoided, and time and effort are saved.

[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], which basically covers the requirements of general surface materials, and is more convenient especially when the incident angle is less than 1 rad. 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 is a 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 zone I in an embodiment of the present invention;

[0038] Figure 6 is a 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 zone II in an embodiment of the present invention;

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

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

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

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

[0044] Fig.12 is the mean relative error (MRE) and root mean square error (RMSE) between the calculated reflectance and the measured results for brick pavement, asphalt pavement, and wooden pavement;

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

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

[0047] Fig.15 It is a schematic diagram of the incident angle distribution law on the building surface;

[0048] Fig.16 It is a schematic diagram of the light in a relatively sparse building complex being reflected to the ground first and then reflected to the surface of surrounding buildings;

[0049] Fig.17 This is a schematic diagram of light reflected directly onto the surfaces of surrounding buildings in a relatively dense building complex;

[0050] Fig.18 It is a schematic diagram of light incident on a diffuse surface at a small angle, and the reflected light cluster appears in the large angle incident on the surrounding surface;

[0051] Fig.19 It is a basic composition flow chart of the building relationship calculation platform;

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

[0053] Fig.21 It is a screenshot of the surface material reflectivity calculation program obtaining the surface material reflectivity required by the environment calculation module; and

[0054] Fig. 22 Schematic diagram of the sun incident on the surface of the material. DETAILED DESCRIPTION

[0055] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments and drawings specifically describe the simplified calculation method and application of the surface reflectivity of non-metallic materials of the present invention.

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

[0057] like Figure 1 As shown, in this embodiment, the material includes non-metallic material and metallic material. When the material is non-metallic material, the simplified calculation method specifically includes the following steps:

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

[0059] (1)

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

[0061] The present invention considers that each tiny incident surface on the surface of the non-metallic material is approximately smooth, that is, the reflection generated on the surface is a mirror reflection, and considers that all transparent structures have no coating or plating.

[0062] 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).

[0063] (2)

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

[0065] The surface material is often a composite system rather than a pure substance, so the refractive index here is the equivalent refractive index of the surface composite material, which is manifested as the deflection of the radiation wave formed after the light enters the surface. In addition to actual measurement, this value can also be obtained by converting the normal emissivity in the commonly used data table.

[0066] The reflectivity of non-metallic surfaces 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. Therefore, it can be considered that the calculation result of the reflectivity is affected by the combined influence of wavelength and direction. In the actual radiation process, the incident angle is usually greater than the refractive angle, that is, the equivalent refractive index is in the interval (0, +∞), and the incident angle is in the interval (0, π / 2).

[0067] like Figure 1-3 As shown, the calculated results of reflectivity at different incident angles (0, π / 2) and different equivalent refractive indices (1, 20]) are plotted.

[0068] 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.

[0069] Figure 4 It is a schematic diagram of zone I in the reflectivity partition of the surface material in an embodiment of the present invention. Figure 5 Graph showing the refractive index and reflectivity of zone I in an embodiment of the present invention. Figure 6 It is a schematic diagram of zone II and zone III in the reflectivity partitioning of the surface material in an embodiment of the present invention. Figure 7 It is a graph of the refractive index and reflectivity of zone II in an embodiment of the present invention. Figure 8 It is a graph of the refractive index and reflectivity of zone III in an embodiment of the present invention.

[0070] Specifically, if Figure 4-8 As shown, within the target range, the reflectivity curve gradually increases from bottom to top with the equivalent refractive index.

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

[0072] The reflectivity curve of zone I remains basically unchanged. In zone I, the reflectivity has nothing to do with 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 shows two different changes due to the difference in equivalent refractive index.

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

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

[0076] The equivalent refractive index of zone II is in the range of (1,5.5), the reflectivity curve increases monotonically within the definition domain, and an inflection point appears between the incident angle of 1.0-1.4 rad. As the equivalent refractive index continues to increase, the inflection point gradually moves to the right.

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

[0078] Among them, the values ​​of a, b, c, and n are shown in Table 1.

[0079] Table 1

[0080]

[0081]

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

[0083] In zone III, the equivalent refractive index is in the range of (5.5,20], and the reflectivity curve decreases first and then increases in the definition domain. A minimum point appears at 1.3 rad, and then rises sharply. As the equivalent refractive index increases, the minimum point moves to the right, showing an exponential function relationship.

[0084] The reflectivity calculation formula of zone III is: where i cr =1.52-1.19×0.72 n .

[0085] Where i n represents the incident angle, ρ represents the reflectivity, i cr Indicates the extreme point of the reflectivity curve.

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

[0087] Table 2

[0088] n <![CDATA[a1]]> <![CDATA[b1]]> <![CDATA[c1]]> n <![CDATA[a2]]> <![CDATA[b2]]> <![CDATA[c2]]> 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 the dimensionless incident angle, which is the ratio of the actual incident angle to the interval length π / 2, that is, I = 2 in / π, for equivalent refractive indices that are within the applicable range of this table but not in the table, the difference method can be used to obtain the corresponding reflectivity value.

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

[0091] Taking the solar radiation problem as an example, the reflectivity of the surface material obtained by the actual measurement result is compared with the reflectivity obtained by the present invention, and the correlation curve between the reflectivity of each surface material and time is drawn 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. The data of various materials are derived from the radiation parameters in the "Urban Residential Thermal Environment Design Standard (JGJ286-2013)", and then the equivalent refractive index is calculated through formula (2), and finally the reflectivity of various materials is obtained.

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

[0093] Fig. 9 is the correlation curve between reflectivity and time in a brick paved road. Fig.10 It is the correlation curve between reflectivity and time in asphalt pavement. Fig.11 is the correlation curve between reflectivity and time in wooden pavement. Fig.12 It is the mean relative error (MRE) and root mean square error (RMSE) between the calculated reflectance and the measured results for brick paved road, asphalt road and wooden road.

[0094] like Figure 9-12 The figure shows the comparison between the calculated results and the measured results. Figure 9-12 It can be seen that the average relative error between the calculation method and the measured results is within 20%, and the root mean square error is within 0.1.

[0095] It can be seen that the zoning calculation method proposed in the present invention takes into account the influence of the change of the solar incidence angle on the reflectivity of the surface material of buildings made of different materials, which helps to improve the accuracy of radiation parameter calculation.

[0096] The simplified calculation method of the surface reflectivity of non-metallic materials of the present invention plays an important role in the calculation process of the radiation environment of building complexes. The existing surface material reflectivity usually follows the standard measurement method of normal incidence, and its applicable range is generally less than 1 rad (about 57°) incident conditions. However, whether it is a single building or a building complex, the sun's incident angle will exceed 1 rad at a large angle, resulting in a large difference between the existing normal reflectivity and the actual reflectivity.

[0097] Fig.13 This is the direct sunlight condition in the building complex at 7:00 in summer. Fig.14 This is the direct sunlight condition in the building complex at 7:00 in winter. Fig.15 It is a schematic diagram of the distribution law of incident angle on the building surface.

[0098] like Figure 13-15 As shown, taking a "nine-square grid" building complex arranged in a positive direction in Shanghai as an example, the direct solar radiation and incident angles on the south-facing, east-facing and west-facing surfaces during the day under strong solar radiation conditions in the four seasons of a typical meteorological year were calculated respectively.

[0099] like Fig.15 As shown in the figure, with 1 rad as the boundary, the incident angle distribution of the central building of the "Nine-square grid" building complex model during the direct sunlight period is given. The red part represents the proportion of time when the incident angle is greater than 1 rad and is marked with red numbers.

[0100] It can be seen that due to the different orientations of the sun wall in different seasons, the proportion of time with an incident angle greater than 1 rad ranges from 0 to 50%, and the east-facing surface is mainly distributed in 1 to 3 hours after sunrise; the west-facing surface has the opposite pattern to the east-facing surface. The phenomenon of large-angle incidence of solar radiation (incident angle greater than 1 rad) has different effects in different seasons, and the proportion is still high even under the condition of shielding by buildings. Therefore, the impact of the incident angle on the reflectivity of the building surface cannot be ignored.

[0101] In addition, when the sun is incident, due to the obstruction of the building complex and the existence of multiple reflections, the building surface may still appear at a large angle when it is reflected and then incident on the surrounding building surfaces again. This process is related to the surface roughness, building height and the spatial position between buildings.

[0102] Fig.16 This is a schematic diagram of how light in a relatively sparse building complex is first reflected to the ground and then reflected again to the surfaces of surrounding buildings. Fig.17 This is a schematic diagram of how light in a densely packed building complex is directly reflected back onto the surfaces of surrounding buildings. Fig.18 It is a schematic diagram of light incident on a diffuse surface at a small angle, and the reflected light cluster appears to be incident on the surrounding surfaces at a large angle.

[0103] like Figure 16-18 As shown, there are mainly three situations: the first is that after the light is incident on the building surface at a large angle, it is first reflected to the ground and then reflected again on the surrounding building surfaces. This situation generally occurs in relatively sparse buildings; the second is that after the light is incident on the building surface at a large angle, it is directly reflected again on the surrounding building surfaces. This situation generally occurs in relatively dense buildings; the third is that the light is incident on the diffuse surface at a small angle, and the reflected light cluster appears to be incident on the surrounding surfaces at a large angle.

[0104] The above requirements can be well solved by using the present invention, which makes up for the current situation that the calculation parameters do not meet the requirements and obtains the key radiation parameters required for the radiation environment calculation.

[0105] Fig.19 It is a basic component flow chart of the building relationship calculation platform.

[0106] like Fig.19 As shown in the figure, the calculation process can be reflected as step 2 of the calculation platform. Note: The independent individuals in the building complex can be simply summarized into two categories: buildings and non-buildings. The various surfaces that make up the interface of the building complex can be divided into three categories according to their radiation properties: the first category is opaque surfaces, such as walls, floor tiles, etc.; the second category is transparent surfaces, such as windows, curtain walls, etc.; the third category is porous surfaces, such as vegetation, etc. The calculation method of the present invention is mainly applicable to the first two types of surfaces, and the calculation method of the third type of surface is already very mature.

[0107] After the architectural spatial relationship is determined, the calculation steps involved in the present invention can be implemented by existing programming software. The present invention takes the method of combining the Grasshopper platform with Python as an example.

[0108] 1. Determination of input conditions.

[0109] The influence of radiation wavelength and direction is the key to calculating the reflectivity of surface materials. 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 sun interacts with the surface. Once the surface material is determined, its equivalent refractive index can be obtained through the table of related physical property parameters. For the angle of incidence, it needs to be determined in combination with the surface position and the position state of the sun at the target time point. The surface position information can be obtained from the spatial relationship module, and the position state of the sun can be obtained by conversion through a typical meteorological year.

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

[0111] like Fig. 20, meteorological parameters are introduced into the Grasshopper platform, and the Ladybug plug-in can be used to obtain the sun position information at the target time point, such as altitude angle and azimuth angle, so that the incident angle of a certain surface of the building complex can be determined.

[0112] 2. Parameter determination procedure.

[0113] After the input conditions are determined, the present invention is used to calculate the reflectivity of the surface material. The Python built into Grasshopper is used as a platform, and the parameter table is embedded therein. Conditional statements are written to make conditional judgments on the incident angle and the equivalent refractive index, and the surface material reflectivity calculation formula is determined. The selection structure includes three levels: the first level is the judgment of the incident angle, that is, the selection of radiation zone I and zone II; the second level is the judgment of the equivalent refractive index, that is, the selection of radiation zone II and zone III; the third level is the selection of coefficients for the specific calculation formula.

[0114] Fig.21 This is a screenshot of the surface material reflectivity calculation program obtaining the surface material reflectivity required by the environmental calculation module.

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

[0116] Once 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 absorptivity can be calculated.

[0118] Directional-spectral absorption rate is calculated as α' λ 9λ,i n )=1-ρ' λ 9λ,i n ), where α is the absorptivity, λ is the wavelength, i n is the incident angle and ρ is the reflectivity.

[0119] For a transparent surface, the absorptivity is 0 in an ideal state, but absorptivity exists in most cases.

[0120] The formula for calculating the directional-spectral transmittance of surface transparent materials is: Where 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 angle of incidence.

[0121] The calculation formula for the spectral-directional absorptivity of surface transparent materials is α' λ 9λ,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, the calculation is 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 goodness of fit is greater than 0.98. While ensuring the calculation accuracy, the calculation process of trigonometric functions and multivariate relationships in the definition formula is simplified, the applicable conditions of the calculation method are clarified, and the occurrence of overfitting is avoided. The problem that the unknown variables in the definition method are difficult to obtain is solved, the inconvenience and tedious work of laboratory measurement are avoided, and time and effort are saved.

[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], which basically covers the requirements of general surface materials, and is more convenient especially when the incident angle is less than 1 rad.

[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, thus greatly improving the practicality.

[0128] According to the present invention, other radiation parameters can be further obtained, including the directional-spectral absorptivity of an opaque surface, the extinction coefficient and the spectral-directional absorptivity of a transparent surface, and the directional-spectral reflectivity of a metal material can be calculated.

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

[0130] The present invention takes into account the influence of the change of the sun's incident angle on the surface reflectivity of the building 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 invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached 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 comprises the following steps: S1, calculate the directional-spectral reflectance by formula (1), (1) In the formula, 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) In the formula, i n is the incident angle, n is the equivalent refractive index of the material when the wavelength is λ; S3, dividing the reflectivity into three regions, wherein 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, calculate the reflectivity of the material surface at different incident angles according to different regions, wherein 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.

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 zone I remains basically unchanged. In zone 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 moves 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 non-metallic materials as claimed in claim 1 in the calculation of the directional-spectral transmittance of surface transparent materials, 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, and i n is the angle of incidence.

7. 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 spectral-directional absorptivity of surface transparent materials, 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 the radiation environment of building complexes.

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 surface reflectivity of materials in a building complex radiation environment, characterized in that: The 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 of the surface reflectivity of non-metallic materials.

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