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Korean scientists have built a light-emitting diode (LED) façade that can be used in combination with building-integrated photovoltaics, with minimal energy loss caused by shading.
Scientists at the Korea Institute for Energy Research (KIER) have developed a grid-type light-emitting diode (LED) display with reflective walls that can be used in combination with Building-Integrated Photovoltaic (BIPV) systems.
“LED displays are electricity-guzzling monsters, consuming a lot of electricity at night without generating electricity,” lead author Dong-Youn Shin told pv magazine . “If grid-type LED screens were installed with BIPV systems, electricity consumption would be greatly reduced.” Many buildings in South Korea have media facade functions, yet BIPV has been deemed to be of poor aesthetic value due to its dull black color.”
The researchers devised a grid-type LED display that instead uses the black color of the BIPV as a background, without the BIPV system behind the LED display being visible to the human eye at a viewing distance of 172 m.
They built the screen with reflective side walls so that sunlight would better reflect off the solar cells. “Our display is much cheaper than conventional transparent LED displays because they are made from photolithographically patterned indium tin oxide (ITO) glasses,” Shin explains. “In contrast, a grid-type LED display is basically made from cheap acrylic plates.”
Conventional flat mountable LED modules have an air gap between the transparent LED module and the BIPV panels, which reduces the overall optical transmittance of the system. In contrast, in the vertical grid-type LED modules created by the Korean group, narrow bars are connected to form vertical grids with attached LEDs, which let more sunlight through the gaps between the modules.
This system configuration would ensure minimal energy performance losses caused by shading. “The grid design leads to minimal shading loss in the range of -3.67% and -4.93%, considered an all-time low when compared to -22.59% for conventional transparent LED films” the scientists say.
Through a series of tests, the team also found that the relative peak power of a 24-cell solar module is greater than 85.6% with highly reflective walls over a vertical grid-type LED module, even at a 60 angle of incidence. degrees, compared to 70.6% with opaque walls. It was also found that the screen time of the system can reach up to 21.74 hours in standalone mode.
The system was presented in the article “ Grid-type LED media facade with reflective walls for building-integrated photovoltaics with virtually no shading loss ”, recently published in Applied Energy . “Usually, an invention contributes to only one industry,” Shin says. “However, grid-type LED displays would contribute not only to electricity-related industries, but also to multiple industries such as PV, BIPV, building construction, displays, advertising, and tourism.” |
