Optical performance simulation method of multilayer semi-transparent system based on different spectra

Abstract

The invention relates to the technical field of optical performance simulation and analysis in the construction industry, and in particular to an optical performance simulation method for a multi-layer semi-transparent system based on different spectra, the method comprising: step 1: acquiring experimental data, and measuring the transmittance τ and reflectance σ of a single-layer material by using a spectrophotometer; step 2: establishing an optical model of the single-layer material by using a ray tracing method, and calculating the single reflectance r and single absorptivity a of the single-layer material; step 3: calculating the spectral extinction coefficient and spectral refractive index of the single-layer material according to the single reflectance and single absorptivity of the single-layer material calculated in step 2; step 4: establishing an optical model of a multi-layer semi-transparent system, and calculating the total transmittance and total absorptivity of the multi-layer semi-transparent system; the invention provides conditions for studying the calculation and analysis of the optical performance and heat transfer performance of semi-transparent doors, windows and windows, and can conveniently provide accurate references for building load calculation and air conditioning unit selection.

Description

Technical Field

[0001] The invention relates to the technical field of optical performance simulation analysis in the construction industry, and in particular to an optical performance simulation method of a multi-layer semi-transparent system based on different spectra. Background Art

[0002] Solar radiation refers to the energy transmitted by the sun to the outside world in the form of electromagnetic waves. According to different wavelengths, solar radiation is mainly divided into ultraviolet rays, visible light, and infrared rays. Different bands carry different energies. Solar radiation is mainly concentrated in the visible light and near-infrared bands. Among all the radiation energy, solar radiation with a wavelength of 0.3-2.5μm accounts for more than 97.7%. If the full wavelength is integrated, the solar constant is about 1368W / m 2 .

[0003] Translucent doors and windows are an important equipment in the construction industry. Their solar radiation transmittance and absorption rate directly affect the building load calculation and air-conditioning unit selection. Before construction, the optical performance analysis of door and window materials is often required; and with the development of science and technology and people's pursuit of energy conservation and environmental protection, the composition of doors and windows is no longer a single glass, but a combination of multiple materials, such as the addition of privacy film and heat insulation film. The functions of various films are different, and the radiation transmittance of light of different wavelengths is also different. Among them, the privacy film has a lower transmittance to the visible light part, and the heat insulation film has a lower transmittance to the infrared part.

[0004] When the above-mentioned different materials form doors and windows to form a translucent multi-layer translucent system, if the traditional method is still used to directly calculate the solar radiation transmittance of the translucent system using the solar radiation characteristics of different layers of materials, the calculation results will be obviously biased due to the lack of consideration of the wavelength effect, so that a result with good light transmittance may be obtained. In actual use, it is found that the solar radiation transmittance of the above-mentioned multi-layer translucent system is almost zero. The experimental data cannot provide valuable reference for the simulation of building loads and the determination of equipment capacity, which seriously affects the calculation of building loads and the selection of air-conditioning units.

[0005] Therefore, how to accurately simulate the optical performance of multi-layer translucent systems in modern doors and windows to provide accurate reference for building load calculation and air conditioning unit selection has become a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a method for simulating the optical properties of a multi-layer semi-transparent system based on different spectra, so as to solve the technical problem that the simulation results of the optical properties of the multi-layer semi-transparent system in the prior art are inaccurate and cannot provide accurate reference for building load calculation and air-conditioning unit selection.

[0007] To achieve the above purpose, the optical performance simulation method of the multi-layer semi-transparent system based on different spectra provided by the present invention adopts the following technical scheme:

[0008] Optical performance simulation methods for multi-layer semi-transparent systems based on different spectra, including:

[0009] Step 1: Obtain experimental data and measure the transmittance τ and reflectance σ of a single-layer material using a spectrophotometer;

[0010] Step 2: Use ray tracing method to establish an optical model of a single-layer material, and calculate the single reflectivity r and single absorption rate a of the single-layer material;

[0011] Step 3: Calculate the spectral extinction coefficient and spectral refractive index of the single-layer material according to the single reflectivity and single absorptivity of the single-layer material calculated in step 2;

[0012] Step 4: Establish an optical model of the multi-layer semi-transparent system and calculate the total transmittance and total absorptivity of the multi-layer semi-transparent system.

[0013] Furthermore, in step 2, the formulas for the transmittance τ and reflectance σ of the single-layer material are obtained according to mathematical induction as shown in equations (1) and (2):

[0014]

[0015]

[0016] Wherein, r is the single reflectivity of the single-layer material to be sought, a is the single absorptivity of the single-layer material to be sought, and by substituting the transmittance τ and reflectivity σ of the single-layer material in step 1, combined with the definition of the single reflectivity and absorptivity of the interface (0<r<1, 0<a<1), the single reflectivity r and single absorptivity a of the single-layer material can be obtained.

[0017] Further, the spectral extinction coefficient and spectral refractive index are calculated according to the single-layer reflectivity r and single-time absorption rate a obtained in step 2. At the same time, according to Bouger's law dI=I×k λ ×dL integral to obtain the single absorption rate of a single layer of material as shown in formula (3):

[0018]

[0019] Where τ is the single transmittance of a single layer of material, θ is the incident angle of light, and d is the thickness of a single layer of material in mm; k λ is the extinction coefficient of a single layer of material at wavelength λ, in mm -1 ; When the incident light is vertically incident, the incident angle is 0°, and the spectral extinction coefficient of the single-layer material at a wavelength of λ can be obtained as shown in (4):

[0020]

[0021] According to Snell's law, when the incident angle is 0°, the spectral refractive index of a single-layer material is as shown in formula (5):

[0022]

[0023] Among them, n 1 is the refractive index of air; n 2λ is the spectral refractive index of a single layer of material at wavelength λ.

[0024] Furthermore, an optical model of a multilayer semi-transparent system is established. The multilayer semi-transparent system includes at least an incident interface k and an adjacent section k+1. Assume that the radiation energy G from the interface k is k , part of the radiation energy is reflected by the interface k, and the remaining radiation energy passes through the interface k; the radiation energy F from the other side of the interface k k′ In the equation, part of the radiation is reflected by the interface k, and the remaining radiation energy passes through the interface k; then G k The radiation energy passing through the interface k and F k′ The radiation energy reflected by the interface k together constitutes G k′ ; G k The radiation energy reflected by the interface k and F k′ The radiation energy passing through the interface k together constitutes F k ;

[0025] If the single reflectivity of interface k is r k , according to the energy balance principle, we get formula (a) and formula (b):

[0026] G k +F k ′=G k ′+F k (a)

[0027] G k ′=(1-r k )G k +r k F k ′ (b)

[0028] According to the deformations (a) and (b), the equivalent transmittance α of the kth interface can be obtained: k and the equivalent forward reflectivity β k As shown in formulas (c) and (d):

[0029]

[0030]

[0031] Among them, β k ′ is the inverse of the equivalent retroreflectivity, which is the multiplication of the transmittance from interface k to layer k+1 and the transmittance from layer k+1 to layer k, that is, and Multiply and deform to get the inverse of the equivalent retroreflectivity β k ′, as shown in formula (e):

[0032]

[0033] When the equivalent forward reflectivity β of the last layer k+1 When the equivalent transmittance α of each interface is known, the equivalent transmittance α of each interface can be calculated. k , if the interior of the semi-transparent system is a large space with no reflected light, β 5 =0, and finally the total transmittance of the multi-layer semi-transparent system is shown in formula (6):

[0034]

[0035] Since the absorption phenomenon within the material from the k layer to the k+1 layer occurs in two processes: i) energy emitted from the k layer interface to the k+1 layer interface; ii) energy reflected from the k+1 layer interface to the k layer interface;

[0036]

[0037] For the material between the k and k+1 interfaces, the absorbed energy Q k→k+1 As shown in formula (g),

[0038]

[0039] The total absorption rate of the multi-layer semi-transparent system is shown in formula (7):

[0040]

[0041] Among them, τ λ，θ is the total transmittance of the multi-layer semi-transparent system, N is the number of interface layers in the multi-layer semi-transparent system, M is the number of material layers in the multi-layer semi-transparent system, and M is less than N by 1, α n Equivalent transmittance of the Nth layer interface; in the above formula (7), the subscript 3 part represents the total energy passing through the kth layer interface, the subscript 1 part represents the energy absorbed by the i process, and the subscript 2 part represents the energy absorbed by the ii process.

[0042] Furthermore, the solar radiation incident angle is calculated. The solar radiation incident angle is determined by the solar altitude angle, the solar azimuth angle of the wall, and the wall inclination angle. The solar altitude angle has three factors: the hour angle h represents the change of the time of the day, the declination δ represents the change of the date, and the geographical latitude φ represents the change of different geographical locations.

[0043] Calculate the declination δ according to formula (8):

[0044]

[0045] Where t represents the date ordinal number of the calculation day in a year;

[0046] Calculate the hour angle h according to formula (9):

[0047]

[0048] Where Lo represents the longitude of the local meridian, Lo m It represents the longitude of the central meridian of the time zone, and e represents the time difference;

[0049] Calculate the solar altitude angle according to formula (10):

[0050]

[0051] Since the wall solar azimuth is determined by the solar azimuth and the wall azimuth, the solar azimuth is calculated according to formula (11):

[0052]

[0053] The wall solar azimuth is the difference between the solar azimuth and the wall azimuth;

[0054] Calculate the solar radiation incident angle according to formula (12):

[0055]

[0056] Where i is the incident angle of solar radiation, is the solar altitude angle, ε is the solar azimuth angle of the wall, υ is the wall inclination angle, and for the vertical wall, υ=90°.

[0057] Furthermore, the single reflectivity of the interface is calculated according to the solar radiation incident angle i and the refractive index n of the material, according to Snell's law (n 1 sini 1 =n 2 sini 2 ) to calculate the refraction angle, and according to formula (13), the single reflectivity of the interface r k , r kSubstituting into formula (c) we can get the interface equivalent transmittance α k :

[0058]

[0059] Furthermore, according to the required interface equivalent transmittance α k Substituting into formula (6), the transmittance of the multi-layer semi-transparent system can be obtained. The solar radiation transmittance τ of the multi-layer semi-transparent system at different incident angles is θ and solar radiation absorption rate ξ θ They are shown in formulas (14) and (15) respectively.

[0060]

[0061]

[0062] Among them, E λ is the solar radiation intensity with wavelength λ.

[0063] The beneficial effects of the optical performance simulation method of a multi-layer semi-transparent system based on different spectra provided by the present invention are: first, according to the spectral optical properties (transmittance and reflectivity) of each layer of material, a model is established to inversely calculate the spectral extinction coefficient and spectral refractive index of the single-layer material, and then the optical model of the semi-transparent system and the hourly solar altitude angle are combined to simulate the optical performance of the semi-transparent system under the multi-layer structure, and finally, combined with the solar radiation spectral distribution, the solar radiation transmittance of the multi-layer structure semi-transparent system is calculated; conditions are provided for studying the calculation and analysis of the optical properties and heat transfer properties of semi-transparent doors and windows, and it can conveniently provide accurate reference for building load calculation and air-conditioning unit selection. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic diagram of the optical model of a single-layer material in the present invention;

[0065] Figure 2 It is a schematic diagram of the optical model of k interface and k+1 interface;

[0066] Figure 3 It is a schematic diagram of the relationship between the reflection angle and the refraction angle between different materials;

[0067] Figure 4 Schematic diagram of the spectral transmittance and solar radiation transmittance of aerogel glass;

[0068] Figure 5 Schematic diagram of indoor solar radiation in aerogel glass obtained by simulating different models. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0070] Nowadays, glass window structures are diverse, and the spectral optical properties of each layer of material vary greatly. The traditional method of simulating the solar radiation transmittance and absorptivity of translucent doors and windows is prone to large errors, which in turn affects the calculation of building loads and the selection of air-conditioning units. Therefore, a simulation method that fully considers the performance differences of each layer of material is urgently needed. The present invention application is proposed based on such considerations:

[0071] Optical performance simulation methods for multi-layer semi-transparent systems based on different spectra, including:

[0072] Step 1: Obtain experimental data and measure the transmittance τ and reflectance σ of a single-layer material using a spectrophotometer;

[0073] Step 2: Use ray tracing method to establish an optical model of a single-layer material, and calculate the single reflectivity r and single absorption rate a of the single-layer material;

[0074] Step 3: Calculate the spectral extinction coefficient and spectral refractive index of the single-layer material according to the single reflectivity and single absorptivity of the single-layer material calculated in step 2;

[0075] Step 4: Establish an optical model of the multi-layer semi-transparent system and calculate the total transmittance and total absorptivity of the multi-layer semi-transparent system.

[0076] In step 2, the formulas for the transmittance τ and reflectance σ of the single-layer material are obtained according to mathematical induction as shown in equations (1) and (2):

[0077]

[0078]

[0079] Schematic diagram of the optical model of a single layer of material Figure 1 As shown, r is the single reflectivity of the single-layer material, a is the single absorptivity of the single-layer material, and the transmittance τ and reflectivity σ of the single-layer material in step 1 are substituted, combined with the definition of the single reflectivity and absorptivity of the interface (0<r<1, 0<a<1), the single reflectivity r and single absorptivity a of the single-layer material can be obtained.

[0080] Calculate the spectral extinction coefficient and spectral refractive index according to the single-layer reflectivity r and single-time absorption rate a obtained in step 2. At the same time, according to Bouger's law dI = I × k λ ×dL integral to obtain the single absorption rate of a single layer of material as shown in formula (3):

[0081]

[0082] Where τ is the single transmittance of a single layer of material, θ is the incident angle of light, and d is the thickness of a single layer of material in mm; k λ is the extinction coefficient of a single layer of material at wavelength λ, in mm -1 ; When the incident light is vertically incident, the incident angle is 0°, and the spectral extinction coefficient of the single-layer material at a wavelength of λ can be obtained as shown in (4):

[0083]

[0084] According to Snell's law, when the incident angle is 0°, the spectral refractive index of a single-layer material is as shown in formula (5):

[0085]

[0086] Among them, n 1 is the refractive index of air; n 2λ is the spectral refractive index of a single layer of material at wavelength λ.

[0087] An optical model of a multi-layer semi-transparent system is established, and the multi-layer semi-transparent system at least includes an incident interface k and an adjacent cross section k+1; Figure 2 As shown, assuming that the radiation energy G from the interface k side k , part of the radiation energy is reflected by the interface k, and the remaining radiation energy passes through the interface k; the radiation energy F from the other side of the interface k k′ In the equation, part of the radiation is reflected by the interface k, and the remaining radiation energy passes through the interface k; then G k The radiation energy passing through the interface k and F k′ The radiation energy reflected by the interface k together constitutes G k′ ; G k The radiation energy reflected by the interface k and F k′ The radiation energy passing through the interface k together constitutes F k ;

[0088] If the single reflectivity of interface k is r k , according to the energy balance principle, we get formula (a) and formula (b):

[0089] G k +F k ′=G k′+F k (a)

[0090] G k ′=(1-r k )G k +r k F k ′ (b)

[0091] According to the deformations (a) and (b), the equivalent transmittance α of the kth interface can be obtained: k and the equivalent forward reflectivity β k As shown in formulas (c) and (d):

[0092]

[0093]

[0094] Among them, β k ′ is the inverse of the equivalent retroreflectivity, which is the multiplication of the transmittance from interface k to layer k+1 and the transmittance from layer k+1 to layer k, that is, and Multiply and deform to get the inverse of the equivalent retroreflectivity β k ′, as shown in formula (e):

[0095]

[0096] When the equivalent forward reflectivity β of the last layer k+1 When the equivalent transmittance α of each interface is known, the equivalent transmittance α of each interface can be calculated. k , if the interior of the semi-transparent system is a large space with no reflected light, β 5 =0, and finally the total transmittance of the multi-layer semi-transparent system is shown in formula (6):

[0097]

[0098] Since the absorption phenomenon within the material from the k layer to the k+1 layer occurs in two processes: i) energy emitted from the k layer interface to the k+1 layer interface; ii) energy reflected from the k+1 layer interface to the k layer interface;

[0099]

[0100] For the material between the k and k+1 interfaces, the absorbed energy Q k→k+1 As shown in formula (g),

[0101]

[0102] The total absorption rate of the multi-layer semi-transparent system is shown in formula (7):

[0103]

[0104] Among them, τ λ，θ is the total transmittance of the multi-layer semi-transparent system, N is the number of interface layers in the multi-layer semi-transparent system, M is the number of material layers in the multi-layer semi-transparent system, and M is less than N by 1, α n Equivalent transmittance of the Nth layer interface; in the above formula (7), the subscript 3 part represents the total energy passing through the kth layer interface, the subscript 1 part represents the energy absorbed by the i process, and the subscript 2 part represents the energy absorbed by the ii process.

[0105] Find the solar radiation incident angle, which is determined by the solar altitude angle, the wall solar azimuth angle and the wall inclination angle. The solar altitude angle has three factors: the hour angle h represents the change of the time of day, the declination δ represents the change of the date and the geographical latitude φ represents the change of different geographical locations.

[0106] Calculate the declination δ according to formula (8):

[0107]

[0108] Where t represents the date ordinal number of the calculation day in a year;

[0109] Calculate the hour angle h according to formula (9):

[0110]

[0111] Where Lo represents the longitude of the local meridian, Lo m It represents the longitude of the central meridian of the time zone, and e represents the time difference;

[0112] Calculate the solar altitude angle according to formula (10):

[0113]

[0114] Since the wall solar azimuth is determined by the solar azimuth and the wall azimuth, the solar azimuth is calculated according to formula (11):

[0115]

[0116] The wall solar azimuth is the difference between the solar azimuth and the wall azimuth;

[0117] Calculate the solar radiation incident angle according to formula (12):

[0118]

[0119] Where i is the incident angle of solar radiation, is the solar altitude angle, ε is the solar azimuth angle of the wall, υ is the wall inclination angle, and for the vertical wall, υ=90°.

[0120] Calculate the single reflectivity of the interface according to the solar radiation incident angle i and the refractive index n of the material. The relationship between the reflection angle and the refraction angle between different media can be referred to Figure 3 As shown, according to Snell's law (n 1 sini 1 =n 2 sini 2 ) to calculate the refraction angle, and according to formula (13), the single reflectivity of the interface r k , r k Substituting into formula (c) we can get the interface equivalent transmittance α k :

[0121]

[0122] According to the required interface equivalent transmittance α k Substituting into formula (6), the transmittance of the multi-layer semi-transparent system can be obtained. The solar radiation transmittance τ of the multi-layer semi-transparent system at different incident angles is θ and solar radiation absorption rate ξ θ They are shown in formulas (14) and (15) respectively.

[0123]

[0124]

[0125] Among them, E λ is the solar radiation intensity with wavelength λ.

[0126] In order to verify the reliability of the present invention, aerogel glass (4mm glass + 8mm aerogel + 4mm glass) was used as an example for experiments. Due to the large difference in the chemical properties of glass and aerogel materials, there are significant differences in optical properties, which are particularly obvious in visible light and near-infrared rays. The radiation transmittance differs by 20%, which can better reflect the correctness of the method of this patent.

[0127] The results were verified under laboratory conditions and compared with the spectrophotometer test results. The incident angle of this part of the radiation was 0°, that is, vertical incidence;

[0128] The transmittance of aerogel glass at different wavelengths is calculated by the method in this patent, and then the solar radiation transmittance of the aerogel glass is obtained by integration;

[0129] At the same time, the solar radiation transmittance of aerogel glass is directly calculated using the traditional method (without considering the influence of wavelength) using the solar radiation characteristics of different layers of materials.

[0130] The calculation results are as follows Figure 4 As shown, it can be seen that the calculation results of the traditional calculation model are too high. The main reason is that the traditional calculation model does not take into account the performance differences between different layers of materials, which leads to a large gap between the calculation results and the actual situation. Therefore, if the traditional method is used to simulate the translucent maintenance structure with large differences in the performance of each layer of materials, it is bound to cause large errors.

[0131] Finally, the real working conditions were used for verification. The roof of the dust removal building of Hunan University in Yuelu District, Changsha City, Hunan Province was selected as the experimental site on August 4. The weather was cloudy on that day. The traditional calculation model and the present invention were used to simulate the indoor total solar radiation conditions, and the optical performance differences caused by different solar radiation incident angles were considered. The simulation results are as follows: Figure 5 As shown, it can be seen that the spectral model simulation results of the present invention are highly consistent with the experimental results, with a Nash coefficient of 0.989 and a root mean square error of 11.14 W / m2. However, the traditional model simulation results have a large error with the experimental results, with a Nash coefficient of 0.763 and a root mean square error of 51.23 W / m2.

[0132] In summary, the optical performance simulation method of a multi-layer semi-transparent system based on different spectra provided by the present invention is suitable for simulating the optical performance of a semi-transparent system with different material properties in each layer;

[0133] The solar radiation transmittance and absorptivity of the translucent system are calculated by combining the solar radiation incident angle and the solar radiation spectral distribution, which provides conditions for the calculation and analysis of the optical properties and heat transfer performance of translucent doors and windows, and can easily provide accurate reference for building load calculation and air-conditioning unit selection.

[0134] In the present invention, unless otherwise clearly stipulated and limited, for example, it can be a fixed connection, a detachable connection, or an integrated one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0135] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for simulating optical properties of a multi-layer semi-transparent system based on different spectra, characterized in that: include: Step 1: Obtain experimental data and measure the transmittance τ and reflectance σ of a single-layer material using a spectrophotometer; Step 2: Use ray tracing method to establish an optical model of a single-layer material, and calculate the single reflectivity r and single absorption rate a of the single-layer material; Step 3: Calculate the spectral extinction coefficient and spectral refractive index of the single-layer material according to the single reflectivity and single absorptivity of the single-layer material calculated in step 2; Step 4: Establish an optical model of the multi-layer semi-transparent system and calculate the total transmittance and total absorptivity of the multi-layer semi-transparent system; The multilayer semitransparent system includes at least an incident interface k and an adjacent interface k+1; assuming that the radiation energy G from the interface k is k , part of the radiation energy is reflected by the interface k, and the remaining radiation energy passes through the interface k; The radiation energy F from the other side of the interface k k′ In the equation, part of the radiation is reflected by the interface k, and the remaining radiation energy passes through the interface k; then G k The radiation energy passing through the interface k and F k′ The radiation energy reflected by the interface k together constitutes G k′ ; G k The radiation energy reflected by the interface k and F k′ The radiation energy passing through the interface k together constitutes F k ; If the single reflectivity of interface k is r k , according to the energy balance principle, we get formula (a) and formula (b): G k +F k ′=G k ′+F k (a) G k ′=(1-r k )G k +r k F k ′ (b) According to the deformations (a) and (b), the equivalent transmittance α of the kth interface can be obtained: k and the equivalent forward reflectivity β k As shown in formulas (c) and (d): Among them, β k ′ is the inverse of the equivalent retroreflectivity, which is the multiplication of the transmittance from interface k to layer k+1 and the transmittance from layer k+1 to layer k, that is, and Multiply and deform to get the inverse of the equivalent retroreflectivity β k ′, as shown in formula (e): When the equivalent forward reflectivity β of the last layer k+1 When the equivalent transmittance α of each interface is known, the equivalent transmittance α of each interface can be calculated. k , if the interior of the semi-transparent system is a large space with no reflected light, β5 = 0, and finally the total transmittance of the multi-layer semi-transparent system is as shown in formula (6): The total absorption rate of the multi-layer semi-transparent system is shown in formula (7): Among them, τ λ，θ is the total transmittance of the multi-layer semi-transparent system, N is the number of interface layers in the multi-layer semi-transparent system, M is the number of material layers in the multi-layer semi-transparent system, and M is less than N by 1, α n =Equivalent transmittance of the Nth layer interface; Since the internal absorption phenomenon of the material from the kth layer to the k+1th layer occurs in two processes: i) energy emitted from the kth layer interface to the k+1th layer interface; ii) energy reflected from the k+1th layer interface to the kth layer interface; In the above formula (7), the subscript 3 represents the total energy passing through the kth layer interface, the subscript 1 represents the energy absorbed in the i process, and the subscript 2 represents the energy absorbed in the ii process.

2. The method for simulating optical properties of a multi-layer semi-transparent system based on different spectra according to claim 1, characterized in that: In step 2, the formulas for the transmittance τ and reflectance σ of the single-layer material are obtained according to mathematical induction as shown in equations (1) and (2): Wherein, r is the single reflectivity of the desired single-layer material, a is the single absorptivity of the desired single-layer material, and by substituting the transmittance τ and reflectivity σ of the single-layer material in step 1, the single reflectivity r and single absorptivity a of the single-layer material can be obtained.

3. The method for simulating optical properties of a multi-layer semi-transparent system based on different spectra according to claim 2, characterized in that: According to the single reflectivity r and single absorption rate a of the single-layer material obtained in step 2, at the same time, according to Bouger's law dI=I×k λ ×dL integral to obtain the single absorption rate of a single layer of material as shown in formula (3): Where τ is the single transmittance of a single layer of material, θ is the incident angle of light, and d is the thickness of a single layer of material in mm; k λ is the extinction coefficient of a single layer of material at wavelength λ, in mm -1 ; When the incident light is vertically incident, the incident angle is 0°, and the spectral extinction coefficient of the single-layer material at a wavelength of λ can be obtained as shown in formula (4): According to Snell's law, when the incident angle is 0°, the spectral refractive index of a single-layer material is as shown in formula (5): Where n1 is the refractive index of air; n 2λ is the spectral refractive index of a single layer of material at wavelength λ.

4. The method for simulating optical properties of a multi-layer semi-transparent system based on different spectra according to claim 1, characterized in that: Calculate the declination δ according to formula (8): Where t represents the date ordinal number of the calculation day in a year; Calculate the hour angle h according to formula (9): Where Lo represents the longitude of the local meridian, Lo m It represents the longitude of the central meridian of the time zone, and e represents the time difference; Calculate the solar altitude angle according to formula (10): The solar azimuth angle is calculated according to formula (11): The solar radiation incident angle is calculated according to formula (12): Where i is the incident angle of solar radiation, is the solar altitude angle, ε is the solar azimuth angle of the wall, υ is the wall inclination angle, and for the vertical wall, υ=90°.

5. The method for simulating optical properties of a multi-layer semi-transparent system based on different spectra according to claim 4, characterized in that: According to the solar radiation incident angle i and the refractive index n of the material, the refraction angle is calculated according to Snell's law (n1 sini1 = n2sini2), and the interface single reflectivity r is calculated according to formula (13): k , r k Substituting into formula (c) we can get the interface equivalent transmittance α k :

6. The method for simulating optical properties of a multi-layer semi-transparent system based on different spectra according to claim 5, characterized in that: According to the required interface equivalent transmittance α k Substituting into formula (6), the transmittance of the multi-layer semi-transparent system can be obtained. The solar radiation transmittance τ of the multi-layer semi-transparent system at different incident angles is θ and solar radiation absorption rate ξ θ They are shown in formulas (14) and (15) respectively. Among them, E λ is the solar radiation intensity with wavelength λ.

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