Visual Performance of a Dual Dynamic Switchable Glazing Assembly in a Field Test Setup

Abstract

Façades with a high window-to-wall ratio in Mediterranean climates pose substantial challenges in terms of overheating and excessive daylight. The control of glare and privacy is often retrospectively improvised using cumbersome internal blinds, while blocking outward view whilst offering protection against overheating and glare, fixed external shading devices lack adaptability and motorised versions of such often cause long-term issues with their moving parts. This paper discusses the visual performance of a prototype dual dynamic insulated glazing unit comprising of two, independently switchable (solar Polymer Dispersed Liquid Crystal and Suspended Particle Device) interlayers designed to control the visible light transmittance into an indoor space while providing for privacy on demand. Using two identical mock-up offices set up as field test chambers, the visual performance provided by the different states of the switchable glazing prototype are compared to that provided by a conventional static insulated glazing unit under identical field test conditions, with and without conventional internal and external shading devices. Results show that the prototype dual dynamic IGU has a potential to provide for a high degree of adaptability, giving building occupants control over their indoor environment to meet visual performance demands.