A modified version of the anisotropic irradiance model of Muneer in combination with a new analytical approach to the visible anisotropic sky areas in an urban environment are in the base of new developed program 3D–SOLARIA. Its purpose is to estimate, display and study the variations in the beam and diffuse components of the solar irradiance and solar irradiation for different time periods on the fragments of the building’s facades.
Our analytical approach treats the background diffuse radiance not as uniform, but as anisotropic as it is indeed in the reality. It allows us to calculate the diffuse irradiance in any point of the considered building surfaces under any type of sky (from clear to overcast) and under “real” sky.
Our methodology reduces the geometry of the visible part of sky to two numerical values (value of SVF and value of its anisotropic correction), which are used in the hourly and daily calculation of the incident diffuse radiation. This allows us to reach very fast results, because the necessary processing time is a function only of the complexity of the 3D model of the considered building and its environment and does not depend by number of sky patches.
The main purpose of the developed methodology is to estimate the incoming solar energy to the surfaces of the considered future building in the different seasons and in this way to allow the architect to study the building shape in order to increase the solar gains in winter and to decrease the solar fluxes in summer in the current urban environment.
The estimation and visualization of the incident irradiance on the all fragments of the building surfaces gives the architect a better idea about the 3D variation of the incoming solar energy and how it depends by the surfaces’ orientation and the environment. The images of the visualized incident irradiance or irradiation are much easier to be understood than numerical tables with estimated values.
Depending of the building’s purpose the architect may need to assure more or less solar radiation on the building facades in the different seasons. The program’s results could help him to find out the suitable places for openings – windows, glazed doors and glazed facades.
These program’s possibilities could help the architect to think more how to use the solar energy and to design buildings with better energy performance.
Figure Legend: Exemplary images, generated in 3D–SOLARIA Irradiation Mode
Stoyanka M. Ivanova.
Civil Engineering and Geodesy, University of Architecture, Sofia, Bulgaria.
The design of a future building with very high energy efficiency demands from the architect to study the available solar resources in this urban environment. The purpose of the presented methodology is to study the variations in all components of the incident solar radiation daily, monthly and seasonally for all building facades. This is realized in the computer program 3D–SOLARIA. In the focus of the paper is the estimation of the background component of the incident diffuse solar irradiation on a building facade under orthogonally obstructed sky, using anisotropic sky view factors.