Building Wind Energy Potential Prediction Method Based on the Combination of Actual Urban Climate and CFD Simulation

Abstract

The present invention relates to a method for predicting the wind energy potential of buildings based on the combination of actual urban climate and CFD simulation, which includes the following steps: obtaining urban wind climate data; establishing a corresponding model in CFD software according to the building group target to be studied; normalizing the wind speed data obtained from CFD simulation; expanding the existing wind direction data calculated by CFD simulation into a complete 360-degree wind direction data according to the linear interpolation method; calculating the wind energy potential of the research object by using the wind direction and the cube of the wind speed in the obtained actual climate as the weights for wind energy potential calculation; modifying the model of the research object according to the optimization variables of the building group layout to be studied; comparing the calculation results of the wind energy potential under different layouts obtained, and selecting the building layout with better wind energy. The present invention realizes the quantitative analysis of the wind energy potential of buildings, and provides a strong guidance for the optimization of the building group layout.

Description

Technical Field

[0001] The present invention relates to a method for predicting the wind energy potential of buildings, specifically to a method for predicting the wind energy potential of buildings based on the combination of actual urban climate and CFD simulation, belonging to the field of urban and building simulation analysis. Background Art

[0002] At present, the application of renewable energy in the building field has developed rapidly, and wind energy has attracted much attention due to its good complementarity with solar energy. In recent years, how to scientifically and reasonably layout buildings to make full use of wind energy resources to improve the wind power generation efficiency has become a key topic in the research of building renewable energy.

[0003] In the research of urban wind environment, the CFD (Computational Fluid Dynamics) simulation method has been widely used in the research of urban wind environment due to its economy and high accuracy. However, restricted by the input conditions of CFD simulation, a single simulation can only consider the wind energy flow field condition of buildings under a single wind direction and constant wind speed, which restricts its prediction ability for complex actual environments to a certain extent.

[0004] Meanwhile, in the actual urban environment, the wind speed and direction change with time, and the prediction of the wind energy potential of buildings should consider the different distribution frequencies of wind speed and direction. If only predicting the wind energy of a building group based on a single wind direction, the true wind energy condition of the building group cannot be comprehensively reflected.

[0005] Therefore, to solve the above problems, it is indeed necessary to provide an innovative method for predicting the wind energy potential of buildings based on the combination of actual urban climate and CFD simulation to overcome the defects in the prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for predicting the wind energy potential of buildings based on the combination of actual urban climate and CFD simulation, which can evaluate the wind energy potential of buildings, aiming to quantitatively and comprehensively predict the influence of the layout mode of building groups on the wind energy potential, and thus provide strong guidance for the optimization of the layout of building groups.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is: a method for predicting the wind energy potential of buildings based on the combination of actual urban climate and CFD simulation, which includes the following process steps:

[0008] 1), Obtain urban wind climate data;

[0009] 2), CFD simulation data acquisition: Establish a corresponding model in CFD software according to the target of the building group to be studied;

[0010] 3), Normalize the simulation data: Normalize the wind speed data obtained by CFD simulation;

[0011] 4), Deduce the complete wind direction data: According to the linear interpolation method, expand the existing wind direction data obtained from the CFD simulation calculation into complete 360-degree wind direction data;

[0012] 5), Calculate the wind energy potential: Use the wind direction and the cube of the wind speed in the actual climate obtained in step 1) as the weights for calculating the wind energy potential, and calculate the wind energy potential of the research object;

[0013] 6), Calculate the wind energy potential of different layouts: Modify the research object model according to the optimization variables of the building group layout to be studied, and repeat steps 3) to 6);

[0014] 7), Compare the wind energy potential of different layouts: Compare the calculation results of the wind energy potential under different layouts obtained, and select the building layout with better wind energy.

[0015] The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation of the present invention is further as follows: In the above step 1), the obtained urban wind climate data covers the wind direction and wind speed data corresponding to each hour in 8760 hours of the typical year of the city.

[0016] The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation of the present invention is further as follows: In the above step 1), obtain the urban wind climate data through a weather station or Chinese standard weather data.

[0017] The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation of the present invention is further as follows: The above step 2) is specifically as follows:

[0018] 2-1), Select a building group of a nine-square grid;

[0019] 2-2), Divide 360-degree wind direction evenly into 36 directions, and each direction corresponds to an independent simulation calculation;

[0020] 2-3), Collect the wind speed values at the installation sites of each wind turbine under different calculation directions.

[0021] The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation of the present invention is further as follows: The wind speed value in the above step 2-3) is solved by the following function:

[0022] ;

[0023] Where: is the inlet wind speed function;

[0024] k is the von Kármán constant;

[0025] z dis the zero-plane displacement height;

[0026] z0 is the aerodynamic roughness length;

[0027] is the friction velocity.

[0028] The method for predicting the building wind energy potential based on the combination of actual urban climate and CFD simulation of the present invention is further as follows: In the step 3), the power generation of the wind turbine is proportional to the cube of the received wind speed. During the normalization process, the wind speed data is cubed;

[0029] Complete the normalization process for the simulation data according to the following formula:

[0030]

[0031] Where: refers to the wind energy situation of the research object at the orientation angle;

[0032] d refers to a certain orientation angle of this case, and there are m in total;

[0033] i refers to a certain installation site of this case, and there are n in total;

[0034] U i refers to the simulated wind speed result of the i-th installation site in the research object;

[0035] U ref refers to the reference wind speed of this installation site, that is, the wind speed at the same height as this installation site without being blocked.

[0036] The method for predicting the building wind energy potential based on the combination of actual urban climate and CFD simulation of the present invention is further as follows: In the step 4), complete the interpolation according to the following method:

[0037] ;

[0038] Where: refers to the wind energy situation of the research object at the orientation angle;

[0039] and are two adjacent wind directions among the m existing wind directions obtained by CFD simulation calculation;

[0040] D represents any wind direction between and that has not been calculated by CFD simulation.

[0041] The method for predicting the wind energy potential of a building based on the combination of actual urban climate and CFD simulation of the present invention is further as follows: In the said step 5), the method for calculating the wind energy potential is as follows:

[0042]

[0043] Wherein: is the wind energy potential prediction parameter of the research object;

[0044] is the wind direction at the k-th hour of the year in this city;

[0045] is the wind speed at the k-th hour of the year in this city;

[0046] k refers to a certain hour in the meteorological data of a typical year, and there are 8760 in total.

[0047] The method for predicting the wind energy potential of a building based on the combination of actual urban climate and CFD simulation of the present invention is also as follows: In the said step 6), the variable of the orientation of the building group is optimized. By changing the orientation of the building group, the inlet wind direction of the model in the CFD model is adjusted to 22.5°, 45°... 337.5° of the original inlet wind direction, and the wind energy potential is calculated.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. The method for predicting the wind energy potential of a building based on the combination of actual urban climate and CFD simulation of the present invention combines the actual urban climate data with CFD simulation using normalization, interpolation method and weighted average method, and solves the problem that the traditional CFD simulation prediction method only depends on a single wind direction and cannot comprehensively reflect the real wind energy situation of the building.

[0050] 2. The present invention solves the problem of difficult quantitative comprehensive prediction of the influence of the building group layout on the wind energy potential through scientific calculation methods and data processing processes, realizes the quantitative analysis of the building wind energy potential, and provides strong guidance for the optimization of the building group layout.

[0051] 3. The present invention has strong adaptability, can meet the complex wind environment requirements of different cities, and provides an expandable solution for the optimization of the building group layout.

[0052] 4. The present invention has good robustness and can stably operate under different research objectives such as arranging multiple installation sites at different positions of a single building or arranging installation sites in multiple buildings, and effectively predict its wind energy potential.

[0053] 5. The present invention has flexibility in computing power input. It can comprehensively adjust the number of CFD simulation calculations according to the result accuracy of actual requirements and the computable power cost that can be invested, and rationally utilize resources. Description of the Drawings

[0054] Figure 1 is a flowchart of the method for predicting building wind energy potential based on the actual climate of a city combined with CFD simulation of the present invention.

[0055] Figure 2 is a line graph of the wind climate data of a certain city in a specific embodiment of the present invention.

[0056] Figure 3 is a schematic diagram of a building group of the present invention.

[0057] Figure 4 is the calculation result of the wind energy potential in a specific embodiment of the present invention. Detailed Embodiment

[0058] Please refer to the attached Figure 1 As shown, the present invention is a method for predicting building wind energy potential based on the actual climate of a city combined with CFD simulation, which includes the following process steps:

[0059] 1), Obtain the wind climate data of the city; specifically, obtain the wind climate data of the city through a meteorological station or Chinese Standard Weather Data (CSWD). The obtained wind climate data of the city should cover the wind direction and wind speed data corresponding to each hour in 8760 hours of a typical year in the city, as shown in the attached Figure 2 figure.

[0060] 2), CFD simulation data collection: According to the building group target to be studied, establish a corresponding model in the CFD software. The specific process is as follows:

[0061] 2-1), Select a building group of a nine-square grid, as shown in the attached Figure 3 figure. For the convenience of calculation, in this embodiment, the model is set to a scaling ratio of 1:300 with the actual size, H b1 = H b2 = H b3 = 400 mm, L = D = 133.33 mm, W = 200.00 mm.

[0062] 2-2), Considering the actual result accuracy requirements and the computable power cost that can be invested, the 360-degree wind direction is evenly divided into m directions as needed, and each direction corresponds to an independent simulation calculation. In this embodiment, the 360-degree wind direction is evenly divided into 36 directions, and each direction corresponds to an independent simulation calculation. Since the model in the appendix Figure 3 is symmetric, only the 18 wind directions shown in the figure need to be calculated.

[0063] Furthermore, it is set that the installation site is 0.1H above the center point of the roof of each building, where H refers to the building height. The software used for CFD simulation is FLUENT, and the computational domain extends 5H b1 upward with H b1 as the reference height, extends 5H b1 in the wind inlet direction, extends 15H b1 in the outlet direction, and extends 5H b1 to the left and right; the multi-zone method is used for mesh generation, the mapping type is hexahedron, the surface size of the building is adjusted and inflated, the surface size is adjusted to 0.005 m, the thickness of the first inflation layer is 0.005 m, the number of inflation layers is 5, and the growth rate is 1.2. In terms of boundary conditions, the inlet is a velocity-inlet, the outlet is set as a pressure-outlet, the upper and left and right boundaries use symmetry, and the building surface and the ground are non-slip boundary walls (wall).

[0064] 2-3), According to the research needs, the wind speed values at each wind turbine installation site in different calculation directions are collected. Among them, the installation site is a single building or one or more in a building group, which is the installable position of the wind turbine outside the building facade and can be determined according to the actual research needs.

[0065] The wind speed value is solved by the following function:

[0066] ;

[0067] Where: is the inlet wind speed function;

[0068] k is the von Kármán constant;

[0069] z d is the zero-plane displacement height;

[0070] z0 is the aerodynamic roughness length;

[0071] is the friction velocity.

[0072] In this embodiment, the specific parameters are taken as k = 0.4, zd = 13 m, z0 = 0.29 m, u* = 0.55 m / s, and the collected data are shown in Table 1;

[0073]

[0074] 3), Simulation data normalization: To ensure that the wind speed data obtained from CFD simulations can be compared with different urban environments or building cluster layouts, the wind speed data obtained from CFD simulations are normalized.

[0075] It should be noted that the sum of wind speeds between different installation sites or different wind directions does not directly represent their power generation potential. Since the power generation of a wind turbine is proportional to the cube of the received wind speed, the wind speed data are cubed during the normalization process. Specifically, the simulation data are normalized according to the following formula:

[0076]

[0077] Where: Refers to the wind energy situation of the research object at the Orientation angle;

[0078] d refers to a certain orientation angle of this case, with a total of m;

[0079] i refers to a certain installation site of this case, with a total of n;

[0080] U i Refers to the simulated wind speed result of the i-th installation site in the research object;

[0081] U ref Refers to the reference wind speed of this installation site, that is, the wind speed at the same height as this installation site without being blocked.

[0082] The normalized data are shown in Table 2:

[0083]

[0084] 4), Deduce the complete wind direction data: According to the linear interpolation method, the existing wind direction data obtained from CFD simulations are expanded into complete 360-degree wind direction data.

[0085] In this step, the interpolation is completed according to the following method:

[0086] ;

[0087] Where: Refers to the wind energy situation of the research object at the Orientation angle;

[0088] and are two adjacent wind directions among the m existing wind directions obtained from CFD simulation calculations;

[0089] D represents any wind direction that has not been calculated by CFD simulation between and .

[0090] 5), Wind energy potential calculation: Considering the differences in wind environments of different cities comprehensively, using the wind direction and the cube of the wind speed in the actual climate obtained in step 1) as the weights for wind energy potential calculation, the wind energy potential of the research object is calculated;

[0091] Specifically, the method for calculating the wind energy potential is as follows:

[0092]

[0093] Where: is the wind energy potential prediction parameter of the research object;

[0094] is the wind direction at the k-th hour of the year in this city;

[0095] is the wind speed at the k-th hour of the year in this city;

[0096] k refers to a certain hour in the meteorological data of the typical year, with a total of 8760.

[0097] According to the calculation, under the climate conditions of a certain city, the total wind energy potential of the nine installation sites of the building group in this embodiment is 1.70.

[0098] 6), Wind energy potential calculation for different layouts: According to the optimization variables of the building group layout to be studied, modify the research object model, and repeat steps 3) to 6).

[0099] In this embodiment, the variable of the orientation of the building group is optimized. By changing the orientation of the building group, the inlet wind direction of the model in the CFD model is adjusted to 22.5°, 45°... 337.5° of the original inlet wind direction, and so on. Repeat steps 3) to 6) to calculate the wind energy potential.

[0100] 7), Comparison of wind energy potential for different layouts: Compare the calculation results of the wind energy potential under different layouts obtained, and select the building layout with better wind energy.

[0101] The results calculated in this embodiment are as shown in the appendix Figure 4As shown, it can be found that the model has greater wind energy potential values at 0° and 337.5°. Therefore, under the climatic conditions of a certain city, there will be better wind energy potential at 0° or 337.5°, that is, in the layout facing north or north by northwest.

[0102] The above specific implementation manners are only preferred embodiments of this creation, and are not intended to limit this creation. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this creation shall be included within the protection scope of this creation.

Claims

1. A method for predicting the wind energy potential of buildings based on the combination of actual urban climate and CFD simulation, characterized in that: It includes the following technological steps: 1), Obtain urban wind climate data; 2), CFD simulation data collection: According to the building cluster target to be studied, establish a corresponding model in CFD software; 3), Simulation data normalization: Perform normalization processing on the wind speed data obtained from CFD simulation; 4), Deduce complete wind direction data: According to the linear interpolation method, expand the existing wind direction data obtained from CFD simulation calculation into complete 360-degree wind direction data; 5), Wind energy potential calculation: Use the wind direction and the cube of the wind speed in the actual climate obtained in step 1) as the weight for wind energy potential calculation, and calculate the wind energy potential of the research object; The method for calculating the wind energy potential is as follows: Wherein: is the wind energy potential prediction parameter of the research object; is the wind direction at the k-th hour of the year in the city; is the wind speed at the k-th hour of the year in this city; k refers to a certain hour in the meteorological data of a typical year, and there are 8,760 in total; 6), Wind energy potential calculation for different layouts: According to the optimization variables of the building cluster layout to be studied, modify the research object model, and repeat steps 3) to 6); 7), Comparison of wind energy potential for different layouts: Compare the calculation results of wind energy potential under different layouts obtained, and select the building layout with better wind energy.

2. The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation according to claim 1, wherein: In step 1), the obtained urban wind climate data covers the wind direction and wind speed data corresponding to each hour in 8,760 hours of a typical year in this city.

3. The method for predicting the building wind energy potential based on the combination of actual urban climate and CFD simulation according to claim 2, wherein: In step 1), the urban wind climate data is obtained through a meteorological station or Chinese standard weather data.

4. The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation according to claim 1, wherein: Step 2) is specifically as follows: 2-1), Select a building cluster in a nine-square grid; 2-2), Divide 360-degree wind direction evenly into 36 directions, and each direction corresponds to an independent simulation calculation; 2-3), Collect the wind speed values at each wind turbine installation site in different calculation directions.

5. The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation according to claim 4, wherein: The wind speed value in step 2-3) is solved by the following function: ； Wherein: is the inlet wind speed function; k is the von Kármán constant; z is the height of the point where the wind speed needs to be calculated; z d is the zero-plane displacement height; z0 is the aerodynamic roughness length; is the friction velocity.

6. The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation according to claim 1, wherein: In step 3), the power generation of the wind turbine is proportional to the cube of the received wind speed. During normalization processing, the wind speed data is cubed; Complete the normalization processing of the simulation data according to the following formula: Wherein: refers to the wind energy situation of the research object at the orientation angle; Refers to a certain orientation angle, with a total of m; i refers to a certain installation site, and there are n in total; U i It refers to the simulated wind speed result at the i-th installation site in the research object; U ref Refers to the reference wind speed at the installation site, i.e., the wind speed at the same height as the installation site without obstruction.

7. The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation according to claim 1, wherein: In step 4), the interpolation is completed according to the following method: ； Wherein: refers to the wind energy situation of the research object at the orientation angle; and are two adjacent wind directions among the m existing wind directions obtained from CFD simulation calculations; D represents any wind direction not simulated by CFD between and .

8. The method for predicting the building wind energy potential based on the combination of the actual urban climate and CFD simulation according to claim 1, wherein: In step 6), optimize the variable of the orientation of the building cluster. By changing the orientation of the building cluster, adjust the inlet wind direction of the model in the CFD model to 22.5°, 45°... 337.5° of the original inlet wind direction, and perform wind energy potential calculation.

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