Effect of fixed horizontal louver shading devices on thermal performance of building by TRNSYS simulation

Buildings in most countries around the world require large amounts of energ y both for cooling and heating. In fact cooling loads due to solar gains re present about half of global cooling loads for residential as well as non-r esidential buildings. While solar gains through windows contribute largely to these loads, any method of decreasing these gains through shading should be applied with caution. since a balance is required: decreasing cooling l oads by shading may increase heating loads drastically and vice versa. So t he overall energy requirements both for heating and cooling should be consi dered. With this in mind a study was done on the thermal performance of a b uilding by TRNSYS simulation, and a shading model for windows was incorpora ted in it. The shading devices adopted were external fixed horizontal louve rs with different slat lengths and tilts. The study was conducted for four different cities in Italy. The optimization of the shading devices was done with respect to primary energy loads for the whole year, and the optimum d esign was found to depend on location and weather conditions, It was also f ound that shading factor varies with time of day and is different for summe r and winter. For example, for Milan it was found that 70% of gain is cut o ff in summer, while only 40% is cut off in winter by using optimum shading, which is desirable. (C) 2001 Elsevier Science Ltd. All rights reserved.