A calculation method for an optical model of a parallel slat transparent heat-insulating window

Abstract

This invention discloses a calculation method for an optical model of a parallel slat transparent heat-insulating window, including: determining environmental parameters such as the sun's position; determining the solar radiation value and the incident angle of direct radiation; determining the maximum number of reflections and the incident light segmentation ratio; calculating the transmittance of direct-to-direct radiation from the slats; calculating the transmittance and reflectance of direct-to-scattered radiation from the slats; calculating the transmittance and reflectance of scattered-to-scattered radiation from the slats; determining the transmittance, reflectance, and absorptivity of back radiation transmission; calculating the transmittance and reflectance of direct radiation, and the transmittance and reflectance of scattered radiation from the single-pane glass; calculating the solar radiation transmission through the parallel slat transparent heat-insulating window using the net radiation method; and further fitting a simplified formula for calculating solar transmittance. This invention enables designers to perform optical calculations on parallel slat transparent heat-insulating windows and reasonably evaluate their performance and energy-saving potential.

Description

Technical Field

[0001] This invention relates to the field of building door and window technology, and in particular to a calculation method for an optical model of a parallel slat transparent heat-insulating window. Background Technology

[0002] Multi-layered glass facades are favored by modern architects among various composite facade envelope structures due to their superior aesthetic, visual, and acoustic performance. Proper design of multi-layered glass envelopes can improve the indoor light and heat environment and reduce energy consumption. Controlling daylighting through glass may be the most promising and feasible method for future energy solutions. Parallel slat transparent insulated windows consist of a set of transparent insulated slats placed horizontally (at an angle of 0°) between glass cavities, forming a set of horizontally enclosed cavity units. This structure hinders airflow between unit layers, increasing the overall thermal resistance of the glass system, while also effectively improving the optical performance of the multi-layered glass system.

[0003] Currently, optical model calculations for parallel slat transparent insulated windows are still lacking. Unlike traditional blinds, which primarily consider diffuse reflection, the specular reflection on the surface of parallel slats cannot be ignored. Secondly, traditional blinds are mostly opaque, while parallel slats offer high transmittance. Furthermore, the complex solar radiation transfer process in parallel slat transparent insulated windows includes combinations of direct-to-direct radiation, direct-to-scattered radiation, and scattered-to-scattered radiation. The study *Thermal Evaluation of a Double Glazing Facade System with Integrated Parallel Slat Transparent Insulation Material* (PS-TIM) used forward ray tracing to investigate the optical performance of parallel slat transparent insulated windows. This study assumed that the absorptivity of the transparent slats was 0 and the transmittance was extremely high (0.99). The transmittance, reflectivity, and absorptivity of the glass system could be calculated using a ray tracing program. However, this method is somewhat idealized, neglecting the surface absorptivity of the slats and failing to consider the specular reflection characteristics of the slat surface. Therefore, this method is not suitable for calculating the optical model of a generalized parallel slat transparent heat-insulating window. A detailed calculation method for the optical model of a parallel slat transparent heat-insulating window is needed to better study the photothermal performance of the window. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a calculation method for the optical model of a parallel slat transparent heat-insulating window, revealing the radiation transmission process of the parallel slat transparent heat-insulating window when sunlight shines on it, and being able to accurately calculate the instantaneous solar transmittance through the parallel slat transparent heat-insulating window.

[0005] To solve the above-mentioned technical problems, the present invention provides a calculation method for the optical model of a parallel slat transparent heat-insulating window, comprising the following steps:

[0006] Determine the solar position parameters, including the solar altitude angle and the solar azimuth angle;

[0007] Determine the solar radiation value and the angle of incidence of direct radiation;

[0008] The maximum number of reflections and the incident light segmentation ratio are determined based on the slat space dimensions and the light path.

[0009] Calculate the direct-to-direct radiation transmittance of the slab based on the number of reflections, the incident light segmentation ratio, and the slab material properties;

[0010] Based on the radiometric method, a radiation energy balance equation is established to calculate the transmittance and reflectance of direct-scattered radiation from slabs.

[0011] Based on the radiometric method, a radiation energy balance equation is established to calculate the transmittance and reflectance of slab scattering-scattered radiation.

[0012] Determine the transmittance, reflectance, and absorptivity in back radiation transmission;

[0013] The transmittance and reflectance of direct radiation, and the transmittance and reflectance of scattered radiation of single-layer glass are calculated using the ray tracing method.

[0014] Based on the transmittance, reflectance, and absorptance of direct and diffuse radiation from a single-layer transparent glass and transparent heat-insulating slats, the net radiation method is used to calculate the solar radiation transmission through the parallel slat transparent heat-insulating window.

[0015] Optionally, determining the maximum number of reflections and the incident light segmentation ratio based on the slat space dimensions and light path specifically includes: Expression for the maximum number of reflections: Where [] is the Gaussian floor function. θ is the angle of incidence of direct solar radiation. After obtaining the maximum number of reflections n, the incident light segmentation ratio E can be calculated separately. ref,n E ref,n-1 The expression is as follows:

[0016]

[0017] Optionally, the direct-to-direct radiation transmittance of the slab is calculated based on the number of reflections, the incident light segmentation ratio, and the slab material properties. Specifically, when the maximum number of reflections is even, the direct-to-direct radiation transmittance is calculated using the formula... Calculations show that when the maximum number of reflections is odd, the direct-to-direct radiation transmittance is obtained from the formula... Calculate. The reflectivity of direct-to-direct radiation is 0. It is the direct-to-direct specular reflectivity of the front / back surface of the slat.

[0018] Optionally, based on the radiometric method, a radiation energy balance equation is established, and the transmittance and reflectance of the direct-scattered radiation of the slab are calculated. Specifically, this includes: calculating the transmittance and reflectance of the direct-scattered radiation of the reflected part, and then calculating the transmittance and reflectance of the direct-scattered radiation of the transmitted part.

[0019] Furthermore, the transmittance and reflectance of the direct and scattered radiation in the reflected portion are calculated using the radiometric method:

[0020] G=X -1 Q

[0021] Where Q is the radiation source term, X is the coefficient matrix, and F i,j The angle coefficient, It is the scattering-scattering reflectivity of the front / back surface of the slat.

[0022]

[0023] The forward direct-scattering reflectivity and transmittance of the reflective portion are calculated by the following formula:

[0024]

[0025] Furthermore, the transmittance and reflectance of direct and scattered radiation in the transmitted portion are calculated using the radiometric method: a simplified method is employed for calculation, with the radiation source term of the first layer... Q1 = Q2 = Q4 = Q5 = Q6 = 0. The solution process is similar to that of the reflection part; the reflectivity and transmittance through each layer of slats can be calculated sequentially.

[0026] The forward direct-scattering reflectivity and transmittance of the transmitted portion are calculated by the following formula.

[0027]

[0028] Forward transmittance and reflectance of direct-scattered radiation:

[0029]

[0030] Optionally, based on the radiometric method, a radiation energy balance equation is established, and the transmittance and reflectance of the slab-scattered radiation are calculated. Specifically, this includes calculating the transmittance and reflectance of the scattered radiation of the reflected part, and then calculating the transmittance and reflectance of the scattered radiation of the transmitted part.

[0031] Furthermore, the transmittance and reflectance of the scattered-scattered radiation in the reflected portion are calculated using the radiometric method. A simplified method is employed, where the radiation source terms Q1 = 1, Q2 = Q3 = Q4 = Q5 = Q6 = 0. The solution process is similar to that of the direct-scattered radiation process, also requiring transformation into the matrix form G = X. -1 Q is solved. The forward reflectivity and forward transmittance of the scattering-scattering component are calculated using the following formulas.

[0032]

[0033] Furthermore, the transmittance and reflectance of the scattered radiation in the transmitted portion are calculated using the radiometric method: a simplified method is employed for calculation, with the radiation source term of the first layer... Q1 = Q2 = Q4 = 0. Solve for the reflectance and transmittance through each layer of slats sequentially.

[0034] The forward direct-scattering reflectivity and transmittance of the transmitted portion are calculated by the formula.

[0035]

[0036] Scattered radiation: Forward transmittance and reflectance are:

[0037]

[0038] In determining backscattered radiation transfer, the transmittance, reflectance, and absorptivity specifically include: for backscattered-direct radiation transfer, the transmittance, reflectance, and absorptivity are 1, 0, and 0, respectively. For backscattered-scattered radiation transfer, the transmittance, reflectance, and absorptivity are all 0. The transmittance, reflectance, and absorptivity for backscattered-scattered radiation transfer are the same as those calculated for forward scattered-scattered radiation.

[0039] The direct radiation transmittance and reflectance of a single-pane glass are calculated using the ray tracing method. Specifically, the diffuse radiation transmittance and reflectance include calculating the reflectance and transmittance of the glass surface under known solar incidence and emission angles. Further, the direct reflectance and transmittance of the single-pane glass under both forward and reverse directions are calculated. For diffuse radiation, the integral of the direct transmittance and reflectance between 0 and π / 2 is used for calculation.

[0040] Based on the transmittance, reflectance, and absorptance of direct and diffuse radiation from a single layer of transparent glass and transparent heat-insulating slats, the net radiation method is used to calculate the solar radiation transmission through a parallel slat transparent heat-insulating window. Specifically, this includes calculating the net direct radiation and net diffuse radiation of each layer, and then further calculating the absorptance of each layer, the total transmittance of the system, and the reflectance.

[0041] Based on the above calculation method, this invention further fits a simplified formula for calculating solar transmittance, revealing the relationship between solar transmittance and solar altitude angle, solar azimuth angle, and slat size. For south-facing parallel transparent heat-insulating windows, the material properties of the transparent heat-insulating slats are known. Specifically, the steps include:

[0042] Step ①: Input m sets of slat dimensions w / L. Each set of dimensions contains p sets of solar altitude angle h and solar azimuth angle α. The solar altitude angle ranges from 0° to 90°, and the solar azimuth angle ranges from 0° to 360°. However, for south-facing windows, transmittance is only achieved when the solar azimuth angle ranges from 0° to 90° and from 270° to 360°.

[0043] Step 2: The m×p group of solar transmittance τ can be output by following the optical calculation steps for parallel transparent heat-insulating windows;

[0044] Step ③: Using the least squares method, perform polynomial fitting on the p sets of data corresponding to each set of w / L parameters. The fitting variables are the tangent of the solar altitude angle and the cosine of the solar azimuth angle. Let the polynomial to be fitted be:

[0045] τ=a1 tan n h+a2 tan n-1 h+…+a n+1 +b1 cos n α+b2 cos n-1 α+…+b n+1 +c1(tan h cosα) n +c2(tan h cosα) n-1 +…+c n+1 (1)

[0046] Step 4: When the coefficient of determination R of the fitting formula (1) is... 2 When the coefficient of determination is less than 0.95, adjust the tangent of the solar altitude angle and the order n of the cosine of the solar azimuth angle, return to the previous step and re-perform polynomial fitting. When the coefficient of determination is greater than 0.95, output m fitting polynomials with a unified function structure, and output the fitting formula (I) with the unified function structure.

[0047] Step 5: Using the least squares method, perform polynomial fitting on the coefficients of the tangent and cosine values ​​of the solar altitude angle in the m sets of fitting formulas, with the slat size w / L as the fitting variable; the coefficients of the tangent and cosine values ​​of the solar altitude angle in the m sets of fitting formulas include a1,…a n+1 b1,…b n+1 c1,…c n+1 Let the polynomial to be fitted be:

[0048] f(x,s)=t1x s +t2x s-1 +…+t s+1 (2)

[0049] In the formula, x represents the parameters a1, ... a2. n+1 ,b1,…b n+1 ,c1,…c n+1 ;

[0050] When the root mean square error (RMSE) of the coefficient fitting formula (2) is greater than 0.3, adjust the order s of the fitting variable x, return to the previous step and re-perform polynomial fitting. When the root mean square error is less than 0.3, output the fitting formula of the coefficients of the tangent of the solar altitude angle and the cosine of the solar azimuth angle in the fitting formula of m groups.

[0051] Step 6: Substitute the fitting formula (2) of coefficient x into the fitting formula (I) of step 4, and perform mean relative error (MRE) analysis with the solar transmittance calculation results in the optical calculation model. If the mean relative error is less than 10%, output the final fitting formula for calculating the solar transmittance of the parallel slat transparent heat-insulating window. If the mean relative error is greater than 10%, return to step 3, further increase the order of the fitting formula (1), improve the accuracy, and refit.

[0052] By fitting the formula, the relationship between solar transmittance and solar altitude angle, solar azimuth angle, and slat size can be found. Furthermore, for a south-facing parallel transparent heat-insulating window, given any solar altitude angle, solar azimuth angle, and slat size, the solar transmittance can be directly and simply calculated. Attached Figure Description

[0053] Figure 1 This is a flowchart illustrating the calculation steps and formula fitting of the method described in this invention.

[0054] Figure 2 It is the typical light path within the parallel transparent slat layer.

[0055] Figure 3 This is a schematic diagram of the calculation principle for direct-to-direct radiation transfer.

[0056] Figure 4 This is a schematic diagram illustrating the calculation principle of direct-scattered radiation transfer (reflection section).

[0057] Figure 5 It is a direct-scattering radiation transmission slab spatial configuration (transmitted portion).

[0058] Figure 6 It is a scattering-scattering radiation transfer slab spatial configuration (reflective part).

[0059] Figure 7It is a scattering-scattering radiation transmission slab spatial configuration (transmitted portion).

[0060] Figure 8 It is a parallel transparent heat-insulating window for solar radiation transmission. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly described below with reference to the accompanying drawings. The present invention provides a calculation method for an optical model of a parallel slat transparent heat-insulating window, revealing the radiative transmission process of sunlight illuminating a parallel slat transparent partition window, and can accurately calculate and predict the instantaneous solar transmittance through the parallel slat transparent heat-insulating glass window. For example... Figure 1 The calculation flowchart includes the following steps:

[0062] Determine the solar position parameters, including the solar altitude angle and the solar azimuth angle;

[0063] The maximum number of reflections and the incident light segmentation ratio are determined based on the slat space dimensions and the light path.

[0064] Calculate the direct-to-direct radiation transmittance of the slab based on the number of reflections, the incident light segmentation ratio, and the slab material properties;

[0065] Based on the radiometric method, a radiation energy balance equation is established to calculate the transmittance and reflectance of direct-scattered radiation from slabs.

[0066] Based on the radiometric method, a radiation energy balance equation is established to calculate the transmittance and reflectance of slab scattering-scattered radiation.

[0067] Determine the transmittance, reflectance, and absorptivity in back radiation transmission;

[0068] The transmittance and reflectance of direct radiation, and the transmittance and reflectance of scattered radiation of single-layer glass are calculated using the ray tracing method.

[0069] Based on the transmittance, reflectance, and absorptance of direct and diffuse radiation from a single-layer transparent glass and transparent heat-insulating slats, the net radiation method is used to calculate the solar radiation transmission through the parallel slat transparent heat-insulating window.

[0070] Optionally, such as Figure 2 The determination of the maximum number of reflections and the incident light segmentation ratio based on the slat space dimensions and light path specifically includes: Expression for the maximum number of reflections: Where [] is the Gaussian floor function. θ is the angle of incidence of direct solar radiation. After obtaining the maximum number of reflections n, the incident light segmentation ratio E can be calculated separately. ref,n E ref,n-1The expression is as follows:

[0071]

[0072] Optionally, such as Figure 3 The demonstration diagram illustrates how, based on the number of reflections, the incident light segmentation ratio, and the material properties of the slab, the direct-to-direct radiation transmittance of the slab is calculated. Specifically, when the maximum number of reflections is even, the direct-to-direct radiation transmittance is calculated using the formula... Calculations show that when the maximum number of reflections is odd, the direct-to-direct radiation transmittance is obtained from the formula... Calculate. The reflectivity of direct-to-direct radiation is 0. Wherein, It is the direct-to-direct specular reflectivity of the front / back surface of the slat.

[0073] Optionally, based on the radiometric method, a radiation energy balance equation is established, and the transmittance and reflectance of the direct-scattered radiation of the slab are calculated. Specifically, this includes: calculating the transmittance and reflectance of the direct-scattered radiation of the reflected part, and then calculating the transmittance and reflectance of the direct-scattered radiation of the transmitted part.

[0074] Furthermore, such as Figure 4 The slats are divided into 4n blocks, and the index of each block corresponds to the incident light segment. Calculate the block length when n is an even number: Null1 = w - (n-1) × fw, When n is odd, Null1 = w - (n-1) × fw, Null2 = n × fw - w. Where: S ref,n Indicated by E ref,n The irradiated slat portion, S ref,n-1 Indicated by E ref,n-1 The irradiated slat portion; Null represents the slat portion that did not receive radiation.

[0075] The transmittance and reflectance of direct and scattered radiation in the reflected portion are calculated using the radiometric method:

[0076] G=X -1 Q

[0077] Where Q is the radiation source term, and the solution calculation is shown in Tables 1 and 2. X is the coefficient matrix, F ij The angle coefficient, It is the scattering-scattering reflectivity of the front / back surface of the slat.

[0078]

[0079] The forward direct-scattering reflectivity and transmittance of the reflective portion are calculated by the following formula:

[0080]

[0081] Table 1: Source terms for each surface of the slat space when n is even

[0082]

[0083] Table 2: Source terms for each surface of the slat space when n is odd

[0084]

[0085]

[0086] Furthermore, the transmittance and reflectance of the direct and scattered radiation in the transmitted portion are calculated using the radiometric method: a simplified method is employed for the calculation, such as... Figure 5 The first layer of radiation source terms Q1 = Q2 = Q4 = Q5 = Q6 = 0. The solution process is similar to that of the reflection part; the reflectivity and transmittance through each layer of slats can be calculated sequentially.

[0087] The forward direct-scattering reflectivity and transmittance of the transmitted portion are calculated by the following formula.

[0088]

[0089] The forward reflectivity and transmittance of direct-scattered radiation are:

[0090]

[0091] Optionally, based on the radiometric method, a radiation energy balance equation is established, and the transmittance and reflectance of the slab-scattered radiation are calculated. Specifically, this includes calculating the transmittance and reflectance of the scattered radiation of the reflected part, and then calculating the transmittance and reflectance of the scattered radiation of the transmitted part.

[0092] Furthermore, the transmittance and reflectance of the scattered radiation in the reflected portion are calculated using the radiometric method: a simplified method is employed for the calculation, such as... Figure 6 The radiation source terms are Q1 = 1, Q2 = Q3 = Q4 = Q5 = Q6 = 0. Solving this process is similar to solving the direct-scattered radiation process, and it also needs to be transformed into the matrix form G = X. -1 Q is solved. The forward reflectivity and forward transmittance of the scattering-scattering component are calculated using the following formulas.

[0093]

[0094]

[0095] Furthermore, the transmittance and reflectance of the scattered radiation in the transmitted portion are calculated using the radiometric method: a simplified method is employed for the calculation, such as... Figure 7 The first layer of radiation source terms Q1 = Q2 = Q4 = 0. Solve for the reflectance and transmittance through each layer of slats sequentially.

[0096] The forward direct-scattering reflectivity and transmittance of the transmitted portion are calculated by the formula.

[0097]

[0098] Scattered radiation: Forward reflectivity and transmittance are:

[0099]

[0100] In determining backscattered radiation transfer, the transmittance, reflectance, and absorptivity specifically include: for backscattered-direct radiation transfer, the transmittance, reflectance, and absorptivity are 1, 0, and 0, respectively. For backscattered-scattered radiation transfer, the transmittance, reflectance, and absorptivity are all 0. The transmittance, reflectance, and absorptivity for backscattered-scattered radiation transfer are the same as those calculated for forward scattered-scattered radiation.

[0101] The direct radiation transmittance and reflectance of a single-pane glass are calculated using the ray tracing method. Specifically, the diffuse radiation transmittance and reflectance include calculating the reflectance and transmittance of the glass surface under known solar incidence and emission angles. Further, the direct reflectance and transmittance of the single-pane glass under both forward and reverse directions are calculated. For diffuse radiation, the integral of the direct transmittance and reflectance between 0 and π / 2 is used for calculation.

[0102] Based on the transmittance, reflectance, and absorptance of direct and diffuse radiation from a single layer of transparent glass and transparent insulating slats, the net radiation method is used to calculate the solar radiation transmission through a parallel slat transparent insulating window. Specifically, this includes calculating the net direct and diffuse radiation for each layer, and then further calculating the absorptance of each layer, the total transmittance of the system, and the reflectance. Figure 8 Assume the interior is an ideal blackbody.

[0103] For direct radiation, the radiation energy balance equation is as follows, where I b Direct solar radiation received by the vertical facade:

[0104]

[0105] For direct-scattering and scattered-scattering radiation transfer, the radiation energy balance equation is as follows, where I d Solar diffused radiation received by the vertical facade:

[0106]

[0107] The absorptivity of each layer, the total transmittance of the system, and the reflectivity can be calculated using the following formula.

[0108]

[0109] Based on the above calculation method, this invention further fits a simplified calculation formula for solar transmittance, revealing the relationship between solar transmittance and solar altitude angle, solar azimuth angle, and slat size. In this embodiment, the south-facing parallel transparent heat-insulating window has a surface transmittance of 0.7, a surface absorptivity of 0.1, and a surface reflectivity of 0.2 for the transparent heat-insulating slat surface.

[0110] Step ①: Input 6 sets of slat dimensions w / L, with w / L values ​​of 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6 respectively. Each set of slat dimensions contains 289 sets of solar altitude angles h and solar azimuth angles α. The solar altitude angle ranges from 0° to 90°, and the solar azimuth angle ranges from 0° to 360°. However, for south-facing windows, transmittance is only achieved when the solar azimuth angle ranges from 0° to 90° and from 270° to 360°. To simplify the formula, the tangent of the solar altitude angle, the cosine of the solar azimuth angle, and the slat dimensions are used as fitting variables.

[0111] Step ②: Following the optical calculation steps for parallel transparent heat-insulating windows, 6×289 sets of solar transmittance τ can be output;

[0112] Step ③: Using the least squares method, perform polynomial fitting on the 289 sets of data corresponding to each set of w / L parameters. The fitting variables are the tangent of the solar altitude angle and the cosine of the solar azimuth angle. Let the polynomial to be fitted be:

[0113] τ=a1tan n h+a2tan n-1 h+…+a n+1 +b1cos n α+b2cos n-1 α+…+b n+1 +c1(tan h cosα) n +c2(tan h cosα) n-1 +…+c n+1

[0114] Step 4: When the coefficient of determination R of the fitting formula in step 3 is... 2 When the coefficient of determination is less than 0.95, adjust the tangent of the solar altitude angle and the order n of the cosine of the solar azimuth angle, return to the previous step and re-perform polynomial fitting. When the coefficient of determination is greater than 0.95, output 6 sets of fitting formulas.

[0115] When w / L = 0.6:

[0116] τ t =-0.0744tanh+0.4550cosα+0.0167tan 2 h - 0.0917tanhcosα + 0.0777

[0117] When w / L = 0.8:

[0118] τ t =-0.0812tanh+0.4346cosα+0.0185tan 2 h - 0.0913tanhcosα + 0.0746

[0119] When w / L = 1.0:

[0120] τ t =-0.0954tanh+0.4165cosα+0.0229tan 2 h - 0.0910tanhcosα + 0.0718

[0121] The fitting formulas for w / L = 1.2, 1.4, and 1.6 also have the same structure.

[0122] The unified function structure of the final six sets of fitting formulas is as follows:

[0123] τ=Atanh+Bcosα+Ctan 2 h+Dtanhcosα+E (3) Under the 6 sets of slat dimensions, the values ​​of parameters A, B, C, D, and E in the polynomial are different. These parameters are related to the slat dimensions.

[0124] Step 5: Using the least squares method, perform polynomial fitting on the coefficients of the tangent and cosine values ​​of the solar altitude angle in the 6 sets of fitting formulas, with the slat size w / L as the fitting variable; the coefficients of the tangent and cosine values ​​of the solar altitude angle in the m sets of fitting formulas include A, B, C, D, and E; let the polynomial to be fitted be:

[0125] f(x,s)=t1x s +t2x s-1 +…+t s+1 (4)

[0126] In the formula, x represents parameters A, B, C, D, and E;

[0127] When the root mean square error (RMSE) of the coefficient fitting formula (4) is greater than 0.3, adjust the order s of the fitted variable x, return to the previous step and re-perform polynomial fitting. When the RMSE is less than 0.3, output the fitting formulas of the coefficients of the fitted variables in the fitting formulas of m groups:

[0128]

[0129] E has a quadratic function relationship with w / L. When w / L = 0.6 to 1.6, e can be taken as 0.074 for calculation.

[0130] Step 6: Substitute the fitting formula (4) of coefficient x into the fitting formula (3) and perform average relative error (MRE) analysis with the calculation results of solar transmittance in the optical calculation model. If the average relative error is less than 10%, output the final fitting formula for calculating the solar transmittance of the parallel slat transparent heat-insulating window. If the average relative error is greater than 10%, return to step 3 and further increase the order of the fitting formula to improve the accuracy and refit.

[0131] The fitting formula reveals the relationship between solar transmittance and solar altitude angle, solar azimuth angle, and slat size. Furthermore, for a south-facing parallel transparent heat-insulating window, given any solar altitude angle, solar azimuth angle, and slat size, the solar transmittance can be directly and simply calculated.

Claims

1. A calculation method for an optical model of a parallel slat transparent heat-insulating window, characterized in that, Includes the following steps: Step 1: Determine the sun's position parameters, including the sun's altitude angle and azimuth angle; Step 2: Determine the solar radiation value and the angle of incidence of direct radiation; Step 3: Determine the maximum number of reflections and the incident light segmentation ratio based on the slat space dimensions and light path; Step 4: Calculate the direct-to-direct radiation transmittance of the slab based on the number of reflections, the incident light segmentation ratio, and the slab material properties; Step 5: Based on the radiometric method, establish the radiation energy balance equation and calculate the transmittance and reflectance of direct-scattered radiation from the slab. Step 6: Based on the radiometric method, establish the radiation energy balance equation and calculate the transmittance and reflectance of the slab scattering-scattered radiation; Step 7: Determine the transmittance, reflectance, and absorptivity in the back radiation transmission; Step 8: Calculate the direct radiation transmittance and reflectance, and the scattered radiation transmittance and reflectance of the single-pane glass using the ray tracing method; Step 9: Based on the transmittance, reflectance, and absorptance of direct and diffuse radiation from the single-layer transparent glass and the transparent heat-insulating slat layer, calculate the solar radiation transmission through the parallel slat transparent heat-insulating window using the net radiation method; the calculation of solar radiation transmission through the parallel slat transparent heat-insulating window includes solar transmittance, solar absorptance, and solar reflectance.

2. The calculation method for the optical model of a parallel slat transparent heat-insulating window according to claim 1 further derives a simplified formula for calculating solar transmittance, revealing the relationship between solar transmittance and solar altitude angle, solar azimuth angle, and slat size, characterized in that... Includes the following steps: Step ①: Input m sets of slat dimensions, each set of slat dimensions containing p sets of solar altitude angle and solar azimuth angle; Step ②: The m×p group of solar transmittance can be output by using the optical calculation step nine in claim 1; Step ③: Using the least squares method, perform polynomial fitting on the p sets of data corresponding to each slat size parameter. The fitting variables are the tangent of the solar altitude angle and the cosine of the solar azimuth angle. Let the polynomial to be fitted be: τ11tan n h+a2tan n-1 h+...+a n+1 +b1cos n α+b2cos n-1 α+...+b n+1 +c1(tanhcosα) n +c2(tanhcosα) n-1 +...+c n+1 (1) Step 4: When the coefficient of determination of the fitting formula (1) is less than 0.95, adjust the order n of the tangent of the solar altitude angle and the cosine of the solar azimuth angle, return to the previous step and re-perform polynomial fitting. When the coefficient of determination is greater than 0.95, output m fitting polynomials and the m fitting polynomials have a unified function structure, and output the fitting formula (I) with a unified function structure. Step ⑤: Using the least squares method, perform polynomial fitting on the coefficients of the tangent and cosine values ​​of the solar altitude angle in the fitting formulas of the m groups, with the slat size as the fitting variable; the coefficients of the tangent and cosine values ​​of the solar altitude angle in the fitting formulas of the m groups include a1,…a n+1 b1,…b n+1 c1,…c n+1 Let the polynomial to be fitted be: f(x,s)=t1x s +t2x s-1 +…+t s+1 (2) In the formula, x represents the parameters a1, ... a2. n+1 b1,…b n+1 c1,…c n+1 ; When the root mean square error of the coefficient fitting formula (2) is greater than 0.3, adjust the order s of the fitting variable x, return to the previous step and re-perform polynomial fitting. When the root mean square error is less than 0.3, output the fitting formula of the coefficients of the tangent of the solar altitude angle and the cosine of the solar azimuth angle in the fitting formula of m groups. Step 6: Substitute the fitting formula (2) of coefficient x into the fitting formula (I) of step 4, and perform average relative error analysis with the calculation results in step nine of claim 1. If the average relative error is less than 10%, output the final fitting formula for calculating the solar transmittance of the parallel slat transparent heat insulation window. If the average relative error is greater than 10%, return to step 3, further increase the order of the fitting formula (1), improve the accuracy, and refit.

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