Smart Skin& embeddedelectronics.

Electrochromic glass changes its light transmission in response to a low-voltage electrical signal. Visible light transmittance (VT) range typically 3-60 %, solar heat gain coefficient (SHGC) 0.06-0.40, switching time 2-15 minutes, operating temperature −20°C to +60°C. SageGlass, Halio, View Dynamic Glass differ on switching speed, colour tint, and warranty. PDLC (Polymer Dispersed Liquid Crystal) film switches between opaque and transparent under voltage. Privacy and visual access only ; does not modulate solar heat gain. Conference rooms, partition walls, skylight zones. Thermochromic glazing changes solar transmission in response to temperature (vanadium dioxide phase change at 60-70°C). Passive operation : no wiring, no control system. Best suited where occupant control is not required.

Embedded sensors transform a passive facade element into a data source for the building's energy management system. Sensor placement requires careful coordination : sensors must be thermally decoupled from the frame to avoid measurement bias, accessible for maintenance without disassembling the facade, and connected to the BMS via a protocol compatible with the building's existing infrastructure. We design sensor networks during the facade engineering phase, not as an afterthought, to ensure data quality and avoid costly retrofitting.

Actuators control motorised solar shading (external and internal), automated ventilation flaps, and louvre panels. Their integration with the active glazing layer requires a coordinated control strategy : when electrochromic glass darkens, external shading deployment logic should adapt accordingly. Specified against three performance criteria : response time, acoustic emission, maintenance interval (typically 150,000-200,000 cycles for quality linear actuators).

The BMS is the brain of a smart skin facade : it collects sensor data, executes control logic, and drives the active elements according to rules optimising comfort, energy consumption, and glare management simultaneously. BACnet (ISO 16484-5) dominant in commercial buildings ; KNX (ISO/IEC 14543-3) strong in European markets ; Modbus widely supported by field devices ; MQTT IoT-native. Cybersecurity per IEC 62443 defined from the outset, not added retrospectively.