The incidence of smart windows in building energy saving and future climate projections

The ongoing climate crisis leads to develop smart communities with zero net emissions, and the Responsive Building Envelopes (RBEs) have a crucial role for the goal to be achieved. In this frame the smart windows are promising building envelope solution. With respect to conventional static windows, on one hand they could reduce the building thermal loads and therefore lead to an energy saving and to an improvement of the thermal comfort, on the other hand they could reduce the possible glare, improving the also the visual comfort. There are some smart windows based on widespread technologies and deepen investigated in the scientific literature, such as the electrochromic solution, but there are some others, such as liquid crystal devices, not really investigate, or characterized only by means of simulative analysis, often without calibrated models with experimental data. Thus, the present study aims to investigate, under experimental and numerical point of view, an electric-driven window with liquid crystal technology installed in a full-scale facility located in a Mediterranean climate. A calibrated numerical model is carried out and different windows control logics and future climate projections (to 2050s and 2080s) are analyzed. Among different control logics, the one depending on daylight illuminance level on the work plane shows the best performance, with a total energy saving (lighting and cooling) of -3% with respect a static window in clear state.