Coated photovoltaic glass – a breakthrough in PV technology?

Researchers from the Hong Kong University of Science and Technology and the Hong Kong Polytechnic University have created and tested a new type of coated semi-transparent glass (CSTPV) for use in buildings with solar power systems (BIPV). They say this new glass ensures high solar energy efficiency, keeps heat levels low, and provides good lighting conditions inside the rooms.

Their innovative approach involved adding a passive radiative cooling coating to the glass. “Today, highly transparent passive radiative cooling paints are available that let solar radiation pass through while keeping some cooling properties. This new cooling material could help reduce urban heat island effects caused by carbon dioxide emissions and lower energy use,” the researchers claim.

Higher efficiency and UV protection

The experiment started with producing two samples: a CSTPV glass and an uncoated glass (STPV) using cadmium telluride photovoltaic modules. They were compared with traditional and vacuum windows: a 6.3 mm thick vacuum glass and a 3.2 mm thick single glass. After making the samples, the researchers analyzed their electrical, thermal, and optical properties, then entered the results into specialized simulation software. The study focused on a cube-shaped building with south-facing windows measuring 1.5 m by 1.5 m and a parapet at 0.8 m. Input data for the simulation came from Hong Kong, and the results were confirmed by outdoor measurements.

“The results show that CSTPV windows can reduce the heat gain coefficient by about 15% and achieve better electricity generation, with an annual efficiency about 3% higher than STPV windows,” the researchers said. CSTPV windows also block some ultraviolet rays, reducing long-term health risks. Additionally, all measured samples had correlated color temperature (CCT) values in the neutral light range and color rendering index (CRI) values above 96, ensuring high-quality interior lighting.

Source: pv-magazine.com