Pilot SunSmart window with promising results • Glass in the picture

The ‘smart window’ developed by TNO and partners delivers good performance under realistic practical conditions. This is evident from the results of a first pilot. The SunSmart window is designed to automatically switch between blocking solar heat and letting through. It is optimized to limit energy consumption in a temperate climate with cold winters and hot summers, such as in the Netherlands. The development is in Brightlands Materials Center in Venlo and is part of the Interreg project Sunovate.

Preliminary results first pilot

When the outdoor temperature is high, the smart window blocks solar heat. As soon as the temperature of the SunSmart window drops below a certain value, it lets heat through. The results show that the smart window shifts from transmitting infrared light to blocking it. This happens as soon as direct sunlight hits the window and the ambient temperature is above 20 ° C. Switching back to transmitting infrared light usually happens at night when the glass surface cools. In this way, you can make optimal use of the solar heat in the building. Less energy is also required for both heating and cooling. The extra energy savings can be up to 8%. In monetary terms, the saving compared to the most advanced HR ++ windows is € 23.70 / m² glass per year.

SunSmart technology

TNO and partners launched a pilot in January to test this new SunSmart technology. At the same time, they gather information about the adaptive properties and performance of energy-efficient windows under real conditions. Two 1 m² smart demonstration windows were recently produced and installed at the SolarBEAT test facility in Eindhoven. This is the first time the adaptive thermochromic effect of the new smart windows has been demonstrated under real conditions. So far, the results are promising. Tests run until the end of the year to gather information on changing performances in all four seasons.

‘Smart window’ technology

The active material in the smart window is thermochrome. This means that its optical properties change at a certain temperature. TNO and partners have developed the material for good transparency and with a switching temperature of around 20 ° C, which only changes the transparency of infrared light. The window is thus optimized to save as much energy as possible, while remaining completely transparent to the human eye. The change takes place autonomously and is an inherent property of the laminated glass. This means that the window can be placed in ordinary frames, without special installation requirements. Read more about all dynamic glass techniques here: electrochrome, thermochrome and liquid crystal.

Energy efficiency

Efficient use of sunlight and solar heat can have a major impact on the energy efficiency of buildings. This ensures that less heating is required in winter and less cooling in summer. The new ‘smart window’ automatically adapts the solar radiation to the changing seasons. The technology is designed based on affordable materials and processes with a payback period of less than seven years for end users, according to the developers. Developers expect to be able to bring this technology to market within two to three years. The windows are expected to make a significant contribution to achieving European energy and climate goals. Final goal: an energy- and climate-neutral built environment by 2050.

Partners SunSmart window

The test is part of the Interreg Sunovate project. Sunovate is a project of TNO, Brightlands Materials Center and Solliance, Hasselt University, imec, KU Leuven, Yparex, Everlam, Glass for Glass and Soltech. The project is initiated by TNO. Sunovate is funded by the Interreg VL-NL program, the Dutch government and the provinces of Limburg (NL / VL) and Noord-Brabant (NL).

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