Jensen, Karsten Ingerslev3; Kristiansen, Finn Harken2; Schultz, Jørgen Munthe3
1 Section for Building Physics and Services, Department of Civil Engineering, Technical University of Denmark2 Department of Civil Engineering, Technical University of Denmark3 Department of Buildings and Energy, Technical University of Denmark
– publishable final technical report, EU-FP5 contract ENK6-CT-2001-00549
This project is an example of applied nanotechnology, namely development of a smart window with three operating mode by means of Polymer Network Liquid Crystal (PNLC). The main objective is the implementation, owing to the conception and the realisation of a pre-industrial machine, of a smart window: 1) with sufficient area glazing to meet the market, 2) using a technology which supplies the glazing with three operating modes: 2a) a reflective mode limiting the glazing overheating, 2b) a transparent mode with an excellent transparency, 2c) a scattering mode having a grey scale, 3) for which the operating modes don’t require energy consumption and where the transition from one to the other mode is fast (10 ms) thanks to an applied voltage or voltage pulse, 4) allowing a high solar factor modulation; a Solar Heat Gain Factor (SHGS) between 0.3 and 0.8.and a high daylight modulation between 0.1 and 0.8, 5) with a good lifetime. The outcome of the project was: Several methods were developed and these allowed improving and realisation a number of lab-scale size (from 2 cm sq. up to 15 cm x 30 cm), active films with three optical states (clear, reflective or scattering state) to three original and complementary directions: - increased modulation magnitude of the light flux (reflective band broadening up to 240 nm), - obtain near perfect reflective state and - having a glazing with only one reflective face. A concept study – including simulations - of the optimal pattern and shape for SmartWin II windows as well as realisation and scaling-up of switch-able patterned glass samples for smart windows. A market assessment study of smart windows have been carried out and by taking into account e.g. the fenestration markets, functionality and cost of currently available daylight systems, and it shows a very large market potential for this technology. Conception and realisation of a pre-industrial machine for manufacturing smart windows were obtained. By means of this pre-industrial machine, the sample surface area was progressive increased from lab-scale (approx. 10 cm sq.) up to 60 cm x 80 cm at Mid-Term and up to 68 cm x 120 cm at the end of the project.