Our first sustainable innovation without compromise is our PowerWindow.
PowerWindows are patented and transparent double-paned windows that convert light into electricity. Conventional glass reflects about 30% of the incoming light, we instead collect that with our coating, transport it through the glass and convert it into electricity with solar cells inside the window frame.
In Europe governmental regulations have dictated that every commercial and governmental building construction or renovation has to be energy neutral by 2020. Given the fact average lead-time of such projects is 3-4 years, this is something commercial real estate developers are confronted with today.
Conventional solar panels are limited to the roof or have to be installed off-site. Alternatives are either too intrusive or too costly. PHYSEE’s PowerWindow is the first scalable and cost-efficient solution using the world’s glass to help make these buildings energy neutral.
Possibilities of PowerWindow
Now imagine all the glass in your building having such potential, PowerWindow technology by PHYSEE enables this potential.
Combined with a thermal storage system, PowerWindows can save up to 50% of the total energy demand (electricity and heating) when renovating conventional commercial buildings, and up to 100% of new constructed commercial buildings.
An invisible solution
Our patented coating is what provides our windows with sufficient yield. The coating is a couple of hundred nanometers thick, and is made of an industry-standard host-crystal with a 3% concentration of our luminescent material. In contrast with previous luminescent solar concentrators (LSCs), which were first discovered and heralded in the seventies, our material absorbs energy uniformly over a spectrum ranging from ultraviolet to visible light. It thereafter re-emits this energy in a peak in the near-infrared, resulting in zero overlap in the absorption and emission spectrums. The result is a colorless coating with no self-absorption, making it the first scalable LSC. In fact, increasing the size of a PowerWindow decreases the price per square meter, because the ratio between collection (low-cost) and conversion (high-cost) increases.
The production method used for coating our PowerWindows is called sputter coating, which is a standard in the global glass industry, serving industries ranging from commercial real estate to automotive. Since production fits current standards and the coating is sealed from the environment, matters like warranties, certifications and distribution will go through existing channels. This is what makes our product scalable and applicable in various markets.
A powerful context
The collection of light in our coating happens independent of the window’s orientation towards the sun. Consequently, PowerWindows will work with direct and indirect light. The conversion of light into electricity happens at strips of solar cells in the frame, oriented perpendicularly to the window. The solar cells only need to convert at one specific wavelength, due to the characteristics of our coating. CIGS solar cells allow us to tune their band gap to match the required frequency. The result is minimal heat loss and high efficiency.
The coating is inert and therefore has no risk of losing functionality due to sunlight or weather. All other components are industry standard and come with market conforming warranties of 10-15 years. Furthermore, our windows will work with any type of transparent surface; it can be curved, it can be made of plastic, it can be double or triple paned, you name it.
Many windows use Low-E coatings to filter out sunlight or provide thermal insulation. PowerWindows instead use this light, making it possible to eventually replace the existing coatings. This is, not only often cheaper, but also contributes to the environment, as most coatings make recycling glass difficult because they contain silver. If desirable, PowerWindows can be installed that are virtually indistinguishable from normal windows. However, the efficiency of a PowerWindow scales with its transparency. A normal transparency allows for an efficiency of 20 W/m2, and a darker tinted window can produce up to 45 W/m2. Both options respectively result in a payback period of 3 to 5 years in the Netherlands.