Experimental characterisation of a smart glazing with tuneable transparency, light scattering ability and electricity generation function

Daylighting control technologies have become an essential part of sustainable building design to reduce overheating, glare and energy consumption in buildings. In this paper, a smart glazing system where Building Integrated Photovoltaic (BIPV) is coupled with optically switchable thermotropic hydrogel layer proposed improve the daylighting electricity generation performance traditional BIPV glazings. Thermotropic (TT) hydrogels made various weight percentage combinations hydroxypropyl cellulose (HPC) polymer, gellan gum sodium chloride (NaCl) salt were synthesised first evaluated by visible-near-infrared spectroscopy. Subsequently, small-scale prototypes (BIPV-TT) laminated based on these TT fabricated characterised experimentally under controlled laboratory conditions. The hydrogel, which was 6 wt% HPC, 0.5 4.5 NaCl, selected for further experimental characterisations dynamic outdoor environment, due its appropriate transition temperature 30.7 °C use mild climates wide modulation range solar transmittance from 85.8% (in transparent state) 9.6% light-scattering state). tests conducted Nottingham, UK, typical summer days sunny partial cloudy results showed that using prototype BIPV-TT can up 80% radiation transmitted into test cell, while providing 12% higher electrical power outputs, compared counterpart no applied.