Chinese solar cell and module manufacturer LONGi Solar has shared results of a study conducted by German testing firm TÜV SÜD in Hainan, China to verify the efficiency gains of its PERC bifacial module technology in different surface reflection conditions. For the purpose of the study, these bifacial modules were installed at a height of 1.0 m and 1.5 m and were studied for a period of eight months since September 2018. The installations included bifacial PERC and single sided PERC modules in Ding'an, Hainan.
It also installed an irradiator on the steel of the front module, two irradiators at the top and bottom of the rear module along with thermocouples at the middle and edge of the rear module of each array to test the actual operating temperature.
Findings of the study suggested average daily energy gain per module under the installation height of 1.5 m were 10.1% for grass ground, 15.8% for sand ground, 14.5% for cement ground and 20.59% for white painted environments. These results proved that the higher the surface reflectance, the higher the efficiency gain.
On the white painted surface, the energy gain was found to be as high as 20.59% with a reflectivity of 67.21%, which LONGi says is higher than expected. The energy gain in January 2019 and February 2019 was found to be more than 5% lower than in other months.
"In summary, the TÜV SÜD Hainan pilot project fully verified the excellent power generation performance of the LONGi Hi-MO PERC bifacial modules, and specifically verified the effects of reflectance, installation height, and scattered light ratio on the bifacial energy gain," said LONGi. "The data from the pilot project shows that the bifacial PERC module can generate considerable bifacial energy gain under various reflection conditions, which can significantly improve the efficiency of the power station system and significantly reduce the PV power generation LCOE."
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