Solar windows cut emissions, energy use by 40% in glass skyscrapers

From pv magazine USA

Tall, windowed skyscrapers loom over many major metropolitan areas. These highly glazed buildings are not particularly efficient, but newly published research in One Earth shows that PV windows can help considerably.

“There are preconceived notions of what an energy-efficient building looks like, and it usually is not highly glazed, and it probably isn’t very tall,” said Lance Wheeler, a scientist at NREL. “We found that there are other ways to build high-efficiency buildings.”

Wheeler developed PVWindow, a new type of open-source software on GitHub, to model the impact of the technology. In a report, he and his colleagues describe the building design rules that could lead to “net-zero” or even “net-positive” energy consumption.

Skyscrapers often have a high ratio of window to wall. For example, the 1915 Equitable Building in New York, has a window-to-wall ratio of 25%. This compares to the Bank of America Tower of 2016, which has a of 71% window-to-wall ratio.

The researchers modeled a window-to-wall ratio of 95% to demonstrate the impact glazing has on building energy performance. They also found that triple-paned windows are highly effective in reducing energy use.

“Picture a skyline in, like, New York City where there are these high-rise buildings that are entirely glass,” said Wheeler. “They’re fully glazed. The Freedom Tower has millions of square feet of glass. It could be a power plant in itself.”

In January, building-integrated PV specialist Ubiquitous Energy announced the closing of a $30 million Series B funding round.