A METHOD TO DEFINE SHADING DEVICES CONSIDERING THE IDEAL TOTAL SOLAR ENERGY TRANSMITTANCE

Abstract – A method to determine the optimum total solar energy transmittance (G value) of a shading device is presented. The method consists in determining the ideal hourly G value of the shading device from the results of one energy simulation for the room or building with a bare window (no shading de-vice). These hourly G values are then converted to monthly and annual values using weighted averages. One example is provided where the method is used to determine the optimum properties of a screen to be installed on a south-oriented office room in Stockholm (Sweden). It is shown that the method allows to predict the optimum monthly and annual G values with a relative accuracy. The method is therefore use-ful to identify the optimum shading device properties rapidly, avoiding many iterations in the simulations. 1