A zero-energy building (ZEB) requires an innovative integration of technologies, in which
windows play a paramount role in energy reduction, storage, and generation. This study contributes
to four innovative designs of sliding smart windows. It integrates air-gap (AG), phase change material
(PCM), photovoltaic (PV), and vacuum glazing (VG) technologies. These smart sliding windows are
proposed to generate electricity along with achieving ecient thermal insulations and heat storage
simultaneously. A two-dimensional multiphysics thermal model that couples the PCM melting and
solidification model, PV model, natural convection in the cavity, and the surface-to-surface radiation
model in the vacuum gap are developed for the first time. The model is validated with data in the
literature. The transient simulations were carried out to investigate the thermo-electrical performance
of a window with an area of 1 m by 1 m for the meteorological conditions of Kuwait city on the 10th
of June 2018, where the window was oriented to south direction. The results showed that the total
solar heat energy gain per unit window area is 2.6 kWh, 0.02 kWh, 0.22 kWh, 1.48 kWh, and 0.2 kWh
for the double AG, AG + PV + PCM + VG, PV + PCM + VG, AG + PV + PCM, and the ventilated
AG + PV + PCM + VG, respectively. The results elucidate the advantages of the integration of VG in
this integrated sliding smart window. The daily generated PV electrical energy in these systems is
around 1.3 kWh, 1.43 kWh, and 1.38 kWh for the base case with double AG, PV + PCM + VG, and the
ventilated AG + PV + PCM + VG respectively per unit window area.