Controls for accurate predictions
Estimating the solar radiation falling on the glazing based on sensors can be a challenge, as the external façade elements will shade different glazing area each hour. As an example, the three measuring points (red dots) will provide rather different output depending on the hour, leading to either overusing the shading or underusing it when it is actually required. We use Dynamic Thermal Modelling Tools to predict the incident and transmitted solar radiation for each hour of the year, taking into account the building’s geometry.
Often shading control systems use a simplified method to estimate the transmitted solar radiation. This method includes recording the incident solar radiation on a façade and multiplying the number with the g-value. The problem with this estimation is that the glass specularity is not considered and the predicted number is often too conservative. This means that the shading will be drawn more often than necessary and predicted by the simulations during the design stage. Our approach is to predict the transmitted solar radiation based on the results from Dynamic Thermal Modelling simulation, that takes into account the sun’s position and the glazing specular properties. This method results in better agreement between predicted and real life performance.