Solar-based technologies are finding applications in virtually all aspects of life, providing alternative energy solutions and widening the range of options available to us. We've covered solar air-conditioners, solar car chargers, solar generators, solar water pumps, solar laptop chargers, solar water heaters, solar freezers, solar streetlights, solar roofs, etc. This article will cover another solar energy solution, the solar window.
A window is an opening in a wall, door, roof, or vehicle that allows the passage of light, sound and sometimes air. Windows are typically made of glass. The Romans were the first known to develop a technology for making glass and to use it for making windows. Solar windows are 'windows' made up of panels that serve the dual purpose of producing electricity while allowing the passage of light, sound and air and protecting interiors against adverse weather. Alongside solar roofs, solar glass windows belong to what are collectively known as Building Integrated Photovoltaics (BIPV).
Though prototypes had been in existence since the 1980s, one of the most prominent first movers into the market was a company started by two Delft University of Technology in the Netherlands, Kesterloo and Ferdinand Grapperhaus Jr. and called Physee. In 2016, Physee launched its first product line: the PowerWindow. The window was as transparent as a normal window, but yielded 10W per square metre. The windows remained transparent because the solar cells were incorporated into the edges of the window frame rather than onto the surface. Otherwise, the windows would look like typical solar panels with surfaces covered with metallic soldering.
In 2018, following further development, Physee released a second generation of windows: the SmartWindows. The SmartWindows incorporated extra features including light, air quality, and temperature measuring capabilities.
Michigan State University
By 2008, researchers in the Michigan State University entered the solar window fray. In August last year, solar windows went viral in the name of Michigan State University when MSU announced that it had made-over its Biomedical and Physical Sciences Building with fully transparent solar windows. The project was undertaken by Ubiquitous Energy.
Just like Physee's Powerwindow, the solar window remained transparent because the solar cells were moved to the edges of the glass. But MIT's solar window was by far more sophisticated. The glasses on their windows were specially created plastic materials that acted like 'solar concentrators' made of organic molecules that absorbed just the invisible wavelengths of sunlight, particularly the UV and the near-infrared wavelengths of the white light spectrum and directed them to the edge of the plastic where they are used them to produce electricity.
Watch a demonstration here.
Pros and Cons
Solar windows would mean that a building could entirely produce its own electricity without grid power and without roof-mounted solar panels. But since the highest offering of efficiency, the amount of electricity a solar panel can produce is still at 12% to 15%. The MSU window is estimated at a 10% efficiency, a figure that is far lesser than traditional solar panels.
According to researchers at MSU, there are an estimated 5 billion to 7 billion square metres of glass surface in the United States. Their technology can provide 40% of all the power needed in the United States by generating power from those surfaces. This is about the same as the potential of production from rooftops. They say it can compliment the traditional use of generating from rooftops. It could also help land space on which large arrays of solar panels are often installed that could otherwise be used as farmlands.
However, in comparison to the existing power demands, the existing technologies demand more spaces for any meaningful power generation. Physee offers just 1 square meter of solar generation to 18 square meters of glass. At its pilot installation at the headquarters of the Netherleands largest bank, Rabobank, the most use for the solar windows is that bank employees can charge their phones through USB ports connected to the windows! As peak power production was at just 8-10W. At the MSU installation, a 100 square feet of transparent solar glass installed above the building’s entryway will generate enough electricity to only power lighting in its atrium. At the present, this makes little economic sense because the developer still has to install additional rooftop solar panels to provide the bulk of power.
The Solar Vegan Plant
In 2020, a student at Mapúa University in the Philippines Carvey Maigue won the first edition of The James Dyson Award. Maigue’s AuREUS system was a solar window that manages food wastage and produces electricity at the same time.
Based in part on a technology similar to that of MSU, the windows, made of a special kind of glass, absorb high energy particles and re-emit them as visible light. The UV rays are among the light spectrum that is retained. UV rays are known to help prevent fruit decay and kill bacteria in fruit. The rest are channelled to the edges of the glass where they are converted into electricity.
As is the case with every new innovation, every aspect of human destiny is often disrupted beyond readjustment. Considering the insanely expanding demand for renewable energy, solar windows are one of the many disruptions of the solar industry that mankind may be forced to adjust to, but only in the future with greater optimization of the technology. Mean time, Solarkobo helps its clients in Lagos and Nigeria make the best choice of a solar and inverter system that meets their power needs and fits their budget.