Optical microstructures for advanced architectural glazing

Innovative fenestration system combining seasonal thermal dynamics, daylighting, glare protection and transparency – manufacturing of embedded  3d microstructures

Contact: Dr Andreas Schüler, André Kostro, Jing Gong

The advanced glazing system under development by the group “Nanotechnology for Solar Energy Conversion” combines several functions and can contribute to significantly reduce the energy consumption in buildings with favorably oriented glass façades. In winter, solar gains are used to reduce heating energy requirements; in summer, the proposed device blocks direct radiation and thus limits air conditioning load as well as overheating risks. Judicious use of daylighting furthermore reduces energy needs for artificial lighting and improves the wellbeing of occupants. Our system is based on optical microstructures, and ensures transparency. Produced as a polymer film, the described glazing system will allow easy and low-cost integration into conventional double glazing.

The novel glazing will combine several functions:

daylighting: redirection of incident radiation, projection of daylight deep into the room.

glare protection/visual comfort: protection from direct solar radiation. Minimal impact on vision of the outside.

overheating protection in summer: angular dependent solar transmission, most effective blocking at incidence angles occurring in summer for direct solar radiation.

thermal insulation and solar gains in winter: The glazing shall provide maximum solar gains in winter in order to reduce heating loads. Integration of a film in a double glazing window with a low emissivity thin film coating provides thermal insulation.

Microstructured glazing: Redirected light visible in the lab sample (left), microstructure under electron microscope (middle), computer simulation of optical characteristics with ray tracing (right)

European Patent

EP2882921 – Glazing with embedded microstructures for daylighting and seasonal thermal control, Schueler Andreas, Kostro André

Master thesis in this field:

Novel glazing technology for building envelopes: evaluation of the energy performance and its influence on the thermal control, Sara Vanzo, Politecnico di Torino, 2015

Ongoing PhD thesis

J. Gong, title of PhD thesis: Glazing with novel embedded optical microstructures for seasonal thermal dynamics, daylighting, glare protection and clear view, in various locations and climates, public defense envisaged in April 2019

PhD thesis

A. G. Kostro, J.-L. Scartezzini and A. Schueler (Dirs.). Microstructured glazing for daylighting, glare protection, seasonal thermal control and clear view. EPFL PhD thesis, n° 6465 (2015)

Award

Best paper award in non-imaging optics SPIE 2018 – SPIE Optical Engineering & Applications Conference of 19-20 August 2018, in San Diego, CA, USA for J. Gong, A. Kostro, J.-L. Scartezzini, A. Schüler, Feasibility study on a novel daylighting system with embedded micro compound parabolic concentrators (CPCs), (2018) Proceedings of SPIE – The International Society for Optical Engineering, 10758, art. no. 1075807.

EPFL News & Media

https://actu.epfl.ch/news/spie-non-imaging-optics-best-paper-award-to-jing-g/
https://actu.epfl.ch/news/an-innovative-window-system-earns-a-european-pat-2/

NZZ 23.2.2018 Wie man die Wintersonne einfängt
NZZ online 23.2.2018 Millionen winziger Spiegel lenken Licht ins Haus
EPhttps://www.epfl.ch/labs/leso/wp-content/uploads/2018/05/NZZ180223fo_Tageslichtsysteme.pdfFL News 5.12.16 An innovative window system earns a European patent
24 Heures 5.12.16 L’EPFL développe un vitrage intelligent

Publications

J. Gong, A. Kostro, J.-L. Scartezzini, A. Schüler, Feasibility study on a novel daylighting system with embedded micro compound parabolic concentrators (CPCs), (2018) Proceedings of SPIE – The International Society for Optical Engineering, 10758, art. no. 1075807.

Gong, J., Delaunay, A., Kostro, A., Schüler, A., Development of a novel mechanical micro-engraving method for the high-aspect-ratio microstructures of an advanced window system, (2018) Microelectronic Engineering, 191, pp. 48-53.

J. Gong, A. Kostro, A. Motamed, A. Schüler, Potential advantages of multifunctional complex fenestration system with embedded micro-mirrors in daylighting, Solar Energy, 10 October 2016.

A. Kostro, M. Geiger, J.-L. Scartezzini, A. Schueler, CFSpro: ray tracing for design and optimization of complex fenestration systems using mixed dimensionality approach, Journal of Applied Optics, 55 (19), 5127-5134 (2016)

S. Vanzo, A. Kostro and A. Schüler. Location Based Study of the Annual Thermal Loads with Microstructured Windows in European Climates. Energy Procedia, 6th International Building Physics Conference, IBPC 2015, Torino, Italy, 14-17 June 2015, vol. 78, p. 91-96

A.G. Kostro, M. Geiger, N. Jolissaint, G. Lazo, M. Aymara et al. Embedded microstructures for daylighting and seasonal thermal control. SPIE 2012 International Symposium on Optical Engineering, San Diego, USA, Proceedings of SPIE, 2012