The impact of electrochromic windows on the energy performance of buildings in Mediterranean climates: a case study

Abstract The process of building rehabilitation is usually strongly constrained regarding morphological changes, particularly in the cases of historic or classified buildings. Therefore, in the present chapter the emerging technology of electrochromic (EC) windows is studied, using building energy simulation to assess the effects on energy efficiency in buildings. The phenomena associated with the current state of EC device technology are described, and their potential future trends are discussed. The validation of control procedures for commercially available EC windows is carried out using the ESP-r simulator, using a case study building to be rehabilitated (Faculty of Arts and Humanities, University of Coimbra) through the analysis of the impact of EC technology on energy consumption and thermal comfort. The methodology designed to assess the use of EC windows begins with the calculation, through simulation for a reference case with single glazing windows, of the solar gains and the internal gains of each space, for both heating and cooling seasons, followed by the estimation of the energy savings that result from the application of EC windows. From the results it is concluded that EC windows are an effective solution to the problems associated with the control of solar gain in the east and west facades. The use of EC windows will reduce the annual energy needs, which is clearly an advantage in the cooling season. Generally, it is concluded that the use of EC windows must be defined according to the type of building, or even space, particularly depending on the occupation and the overall internal gains, on the facade characteristics, orientation, and the shading influence of neighboring buildings.