Capturing dynamic thermal behaviour of adaptive opaque façades in building performance simulation: a case study of Zeraf

Adaptive Opaque Façades (AOFs) can reduce building energy demand by dynamically regulating envelope heat transfer, yet their building-level performance remains difficult to assess with standard simulation tools. This study investigates ZERAF, an AOF concept combining Active Insulation System (AIS) and Kinetic Cladding (KC) in vertical-louvre, horizontal-louvre, and rolling-textile configurations. Full-scale prototype measurements, including steady-state AIS characterization and outdoor dynamic tests, were used to calibrate the AIS model and validate AIS and KC models. The calibrated AIS model reproduced the measured active-state transmittance, whereas KC validation showed that standard EnergyPlus could not capture key transient behaviours. EnergyPlus was therefore extended with source-code modifications and complementary routines for switchable exterior boundary conditions, louvre thermal resistance, dynamic radiative coupling, and textile semi-transparency. The resulting models closely matched measured thermal behaviour. Annual simulations of a single-family house in Bolzano showed heating-demand reductions up to 38% and overheating above 28 °C limited to 5 h.