Photovoltaic (PV) windows significantly reduce energy use and CO2 emissions for heavily glazed structures, such as the glittering skyscrapers of large cities, according to research from the National Renewable Energy Laboratory (NREL). This reduction can be as much as 40%.
The research, which was written up in the journal One Earth, describes how PV windows can be a crucial part of creating highly glazed structures that meet net-zero goals. Buildings account for nearly one-third of worldwide energy use, which highlights the need to lower energy demand and associated emissions. High levels of glazing are known to have drawbacks in terms of energy performance and thermal efficiency, but the market continues to favor them.
According to Lance Wheeler, a scientist at NREL, “there are stereotypes about what an energy-efficient structure looks like, and it typically isn’t extensively glazed, and it definitely isn’t very tall.” We discovered that there are various approaches to creating high-efficiency structures.
The usage of PV windows, according to the authors, can help highly glazed buildings achieve reduced levels of energy consumption and carbon emissions. When combined with straightforward geometric adjustments, PV windows in an office building might reduce annual carbon emissions by 2,000 tonnes and save 10,000 to 40,000 gigajoules (GJ) of electricity.
The author’s utilized software they created called PVwindow to model PV windows in building simulations as well as other programs like EnergyPlus and OpenStudio to examine structures with a window-to-wall ratio of 95%.
They put various PV glazing systems to the test on a building in eight cities with various climates. Cities in warmer temperatures, like Tucson, had worse results for lowering energy use and carbon emissions than places with more moderate climates and shifting seasons, like New York City or Denver.
With so much sunshine entering through the windows of highly glazed structures, more energy is needed to keep the occupants cool. PV windows, however, are thermally efficient and use the heat collected to generate power. Additionally, installing PV windows with solar panels outside the structure or on the roof could not only achieve net zero but also produce more energy than the building actually uses.
Even if I don’t want to sit here and argue that we should be building heavily glazed buildings, the researchers aren’t exactly in favor of them either. Wheeler stated that we should be creating extremely energy-efficient structures, but they do want to underline that PV windows and other low-energy and low-emission materials should be taken into account for such structures.
Imagine a skyline in a city like New York City with all-glass high-rise structures, Wheeler suggested. They have the whole glazing. Millions of square feet of glass make up the Freedom Tower. It might function as its own power plant.
According to a study, PV windows can reduce emissions for highly glazed buildings by up to 40%.