Introducing Roberto Habets, Cindy Po Keh Yeung and Luc Leufkens from the Sustainable Buildings Program

Cindy Po Keh Yeung (Researcher), Luc Leufkens (Researcher) and Roberto Habets (Researcher) are part of the Sustainable Buildings team at Brightlands Materials Center. Within the Sustainable Buildings department, they use their expertise in optics, coatings, pigments & colloids, polymers and nano-composites to develop new solutions for optimized use of sunlight and solar heat in the built environment. Accelerating sustainable innovation is one of the Sustainable Building department’s main goals.

What is the essence of the Sustainable Buildings program?

Cindy Po Keh: The Sustainable Buildings Program is all about developing new solutions for optimized use of sunlight and solar heat in the built environment. We develop the knowledge and know-how of using the optical properties of vanadium and how to apply this on glass or polymers. We are working on several solutions to reduce the energy consumption of buildings. The reduction of energy consumption by using optical coatings is the main goal. Our main development is a thermochromic coating (SunSmart) that blocks the solar heat at high temperature (summer), but let the solar heat into the building at low temperatures (winter). The final SunSmart window has the same isolation properties as (high efficiency) HR++ glass, but also regulates the solar heat (autonomously).  Now we are working on scaling up the glass coatings.

What is your role in the Sustainable Buildings program?

Cindy Po Keh: I am mainly working on the chemical coatings for glass. In order to get this coating, a solution with vanadium is used. The glass will be coated by dipping it into this specific solution. Very important in this process is the speed of dipping the glass because this affects the thickness of the coating. When dipped, the glass with coating needs to harden in the oven. This also requires a very specific procedure, so I am currently working on getting a clear overview of this. At the moment we are using 10 by 10-centimeter samples and eventually we will scale up to 100 by 100 centimeters. By scaling up we must of course retain the same quality. This will probably happen in the middle or the end of this year, when we will install a pilot line to produce the 1m^2 thermochromic windows.

Luc: I am also working with with vanadium, but I focus on the pigments (powder form). Essential is that the powders need to be grinded in such a way that it is so small it can reflect as little visible light as possible. As a result, the coating on the glass is optically transparent. The grinding process is challenging: balancing a high degree of crystallinity with an appropriate particle size. Therefore, one of my major goals is optimizing this process.

Roberto: I am involved in both approaches (the pigment route and the direct coating method). Therefore I work closely with Luc and Cindy Poh Keh on both subjects. Additionally, I work on other projects such as ‘the Groene Loper’ in Maastricht. The goal is to make PV panels in such a way that they are more aesthetically pleasing while retaining high efficiency, demonstrating their use within the visible part of the building skin. Hopefully we are able to realize this at the end of June this year.

So what is actually the difference between the use of chemical coating and pigments then?

Luc: The difference is that the vanadium solution needs to be annealed on a glass plate to get its property, whereas the pigments already have the property via the pigment production/syntesis. The advantage of this is that the pigments cannot only be applied to glass, but also to polymer in order to make products such as safety glass, for example.

Cindy Po Keh: A disadvantage of the chemical coating is that the glass first needs to be crystallized, which costs a lot of energy. On the other hand, the grinding process of pigments is also challenging because of the quality loss. These two techniques could probably complement each other in the future.

“In the end, you will realize a reduction in your energy consumption.”

Why is this project so important? And what are the advantages?

Cindy Po Keh: Ultimately, the purchase of this glass must earn itself back. The smart coating blocks infrared light during summer and lets it through during winter. This means your gas and AC-consumption will be lower throughout the whole year. We aim for a payback period of a maximum of 7 years, which is similar to PV-panels. Probably with the current prices of gas and electricity it will be a bit faster. However, it is an investment you make: you have to replace the ordinary glass in your home or building with this particular coating glass. But in the end, you will realize a reduction in your energy consumption. Your whole indoor climate will be improved and there are less fluctuations in temperatures. This is also an advantage for the overall comfort in a building.

What is the most important aspect of this project for you personally?

Cindy Po Keh: Energy savings for sure! When this product eventually enters the market, it will be beneficial for everyone and good for the climate as well.

Luc: At Brightlands Materials Center we obviously work on sustainability. For me, the social aspect is also significant. The fact that we are working on a product that could really make a difference for society is very motivating!

Everything is about saving the planet. I am grateful that I can contribute to this!

Roberto: In line with Cindy Poh Keh and Luc, I find energy savings and the reduction of CO2 very important. Everything is about saving the planet. I am grateful that I can contribute to this!

What would you like to work on in the future?

Roberto: I believe that within the Sustainable Buildings project, a lot of research can be done and developments can be made. The conversion from CO2 to renewable fuels, for example.

“It would be great if all our work and dedication in this product would eventually be used!”

Luc: I really would like to know more about the social aspect. Why do people make choices whether to go for sustainable solutions, such as solar panels? What drives people? The financial aspect? Or the looks? Hopefully more and more people will choose for sustainable solutions in the future.

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