On Energy Efficiency of Night Window Shutters for a Non-Residential Building in Three Major Romanian Cities

An estimation by simulation of the heating energy saving in the cold season due to heavily insulated exterior window shutters closed at night was performed for a low-rise to mid-rise office building in the following three major Romanian cities: Bucharest, Cluj-Napoca and Iasi. All three locations are in a wet temperate continental climate region. The studied building, whose number of floors was varied from 3 to 22, has a rectangle-shaped floor surface. The considered shutters, covering at night only the pane of the window, were assumed to be EPS panels with various thicknesses. In addition to its height more parameters related to the building were varied: its orientation, the height of the windows, the width of the building and the internal gains produced by building lights and equipment. Finally, some short evaluations were performed for a low-U glazing. For the initial glazing used in the simulation, very good potential savings were found. As the assumed heavily insulated shutters do not exist in the Romanian market, three possible design ideas for such shutters have been sketched at the end, all involving a system of guide rails.