SunSmart – The First Affordable, Energy Optimized Smart Window

Abstract

Reducing energy consumption and CO2 emissions becomes more and more important. Not only because of climate change related issues, but also to realize our ambition to become energy independent. To increase the energy-efficiency in buildings, we developed a thermochromic coating for smart windows which is optimized for climates with seasonal changes. Here we present the first results of our smart window performing in real environment. We show that measured solar transmission and thermochromic performance is comparable to measurements in the lab. Furthermore, we present a further optimized thermochromic coating with record optical properties of Tvis = 70% and ΔTsol = 20.1%. Via a building energy simulation study using data from this high performing coating, we show that energy savings between 17-37% can be achieved in the Netherlands, depending on the building type. Furthermore we show that by the use of our new smart window annual energy cost savings between 266 – 553 EUR/a for a single household can be achieved. The thermochromic coating usually accounts for 60 – 70% of these cost savings equaling between 8 – 10 EUR/a per m2 glass. Due to the low material and processing costs for the thermochromic coating, an attractive return on invest with market conform profit margin is possible.