Thermal, luminous and energy performance of solar control films in single-glazed windows: use of energy performance criteria to support decision making

This paper examines the thermal and luminous performance of single-glazed windows with and without solar control films (SCFs) and a venetian blind in actual working conditions. SCF is a passive solution to modify the solar-optical properties of glazing systems, in order to reduce the solar gains and the energy use and to increase the indoor comfort conditions. An experimental campaign was carried out simultaneously in both cooling and heating seasons in two similar office rooms, one with a SCF applied on the internal surface of the glass and the other without any SCF. The experimental data was used to calibrate a model in EnergyPlus and to assess the energy performance of several SCFs with different thermal and optical characteristics for different orientations of the façade. A decision-making framework was applied to identify the potential use of SFCs as retrofitting solutions for single-glazed windows based on energy performance criteria. The results show that SCFs have a real impact in reducing the cooling energy use for South, East and West solar orientations (SCFs with low solar transmittance coefficients show reductions of the cooling energy use up to 86%) due to the reduction of solar gains, while there is an increase in the heating and lighting energy use.Department of Civil Engineering (DECivil) - CERIS Research Institute -, Instituto Superior Técnico, Universidade de Lisboa, in particular to the occupants of the office rooms. Also, the authors would like to extend their thanks to MSc student Duarte Oliveira for the support during the experimental campaign and to the IMPERSOL company for their technical support. The first author wishes to acknowledge the support of FCT (Foundation for Science and Technology) Ph.D Grant FCT PD/BD/127848/201