Microstructured 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

In the media:
NZZ 23.2.2018 Wie man die Wintersonne einfängt
NZZ online 23.2.2018 Millionen winziger Spiegel lenken Licht ins Haus
EPFL News 5.12.16 An innovative window system earns a European patent
24 Heures 5.12.16 L’EPFL développe un vitrage intelligent

Electric lighting, heating and air conditioning are responsible for a large part of electric energy consumption in OCDE countries. In Switzerland, they account for more than 40% of the national energy usage. Lighting accounts for 10% of electrical consumption and heating for 46% of fossil energy consumption. Cooling loads have been increasing over the previous years.

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 favourably 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. A system with microstructures also ensures a certain 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 - photo, under microscope, simulation Figure:
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:

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PhD thesis on this subject:

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)

Recent publications

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

Group publications