1 Simulation models of an electric-driven smart window: energy and visual performances S. Sibilio a, * Department of Architecture and Industrial Design University of Campania Luigi Vanvitelli, Aversa (CE), Italy e-mail: sergio.sibilio@unicampania.it M. Scorpio a , G. Ciampi a , G. Iuliano a , A. Rosato a , L. Maffei a , M. Almeida b a Department of Architecture and Industrial Design University of Campania Luigi Vanvitelli, Aversa (CE), Italy b CTAC, School of Engineering University of Minho (UMinho), Guimarães, Portugal e-mail: michelangelo.scorpio@unicampania.it, giovanni.ciampi@unicampania.it, giuseppina.iuliano@unicampania.it, antonio.rosato@unicampania.it, luigi.maffei@unicampania.it, malmeida@civil.uminho.pt ABSTRACT In this paper, the “in situ” measurements acquired to characterize full-scale electric-driven glasses, able to switch from opaque to transparent state thanks to an electric field, were used to develop, calibrate and validate thermal and visual simulation models of these devices, by means of the simulation software TRNSYS. The validated simulation models were then used, in the same simulation software, to assess the ability of the electric-driven glasses, integrated in historical buildings, to control the indoor comfort conditions as well as to evaluate their ability for reducing cooling energy consumption. The analysis was conducted for an office located in an historical building, comparing the simulation results associated to the electric-driven window with those of a conventional double-glazing window, from energy and visual points of view. The energy and visual analyses were carried out considering two different switching strategies: i) Daylight strategy and ii) Thermal strategy. KEYWORDS Smart windows; Electric-driven windows; Thermal comfort; Visual comfort; TRNSYS; Experimental measurements; Numerical model. INTRODUCTION The heating and cooling of the building is responsible for around 40% of the total worldwide energy demand [1]. The EU residential building stock is largely composed of buildings with poor energy performance. Thus, the energy refurbishment of the existing building stocks presents a high potential for energy savings and reduction of greenhouse gas emissions in the EU countries [2]. In the Italian scenario, about 4 million of buildings were built before 1920 [3] among these, about 2.1 million of building classified as having an historical value have been occupied [4]. Italian Legislative Decree 192/2005 [5] and Italian Legislative Decree 311/2006 [6] exclude historical and architectural heritage from energy retrofitting actions, if the actions cause a significant change of the building integrity. For these reasons, energy * Corresponding author: Sergio Sibilio. Phone: +39 081 5010844. Fax: +39 081 8149266.