| Work Detail |
Chinese scientists have verified the influence of the distance between rows of panels on increasing the performance of a photovoltaic system on a full-scale experimental platform. They found that increased row spacing plays a limited role in enhancing thermal convection, noting that solar irradiance and wind speed are the key parameters for optimal PV system design.A group of researchers led by the University of Science and Technology of China has investigated the influence of the distance between rows of solar modules on the temperature and efficiency of a photovoltaic system and found that excessive distance between rows does not play a significant role in the cooling of the panels by thermal convection or in increasing energy performance.
“Instead, we have discovered that irradiance plays an important role in photovoltaic production, compared to wind speed and row spacing,” Long Shi, lead author of the research, tells pv magazine . “Therefore, ensuring total irradiance is the main consideration when designing photovoltaic plants. On this basis, a reasonable arrangement of the installation mode of the PV array can improve passive cooling to a certain extent.”
Shi also explained that research work showed that greater row spacing did not achieve the expected cooling effect in outdoor tests. “Therefore, it is only necessary to ensure that there is no shadow between adjacent rows of PV panels in practical applications, and the possible cooling effect caused by excessive spacing between rows can not be pursued during practical layout.”
The scientists carried out their experiments with a photovoltaic array composed of 30 modules deployed in a horizontal orientation in 3 columns and 10 rows. The minimum distance between rows was 0.98 m, which ensured that there was no shielding between the components of the photovoltaic field between 9:00 and 15:00 on the winter solstice in the northern hemisphere.
“To improve the land utilization rate, the spacing between rows should be as small as possible,” they also noted. “The IEC 62548-1:2023 and IEC TS 62738-2018 standards stipulate a minimum spacing between rows to ensure that there is no shadow between the two adjacent rows of photovoltaic panels.” They carried out the measurements using a weather station, thermocouples and a power meter from June 10, 2023 to September 5, 2023. “The row spacing was frequently adjusted during the monitoring period to avoid external seasonal influences of air temperature and wind speed.
The series of experiments showed that, contrary to initial expectations, increasing row spacing did not increase the effect of convective heat transfer. It only had a beneficial effect when the irradiance was less than 400 W/m2, while above this threshold the effect was negligible.
The analysis also showed that the production of the photovoltaic system could increase up to 3.9% with a row spacing 1.5 times greater than the minimum threshold; The surface temperature decreased by 1.86 ºC and the photovoltaic and energy performance increased by 3.53% when the wind speed went from 0 to 2.4 m/s.
The scientists concluded that further separation between grosses should be avoided, as its limited effects do not compensate for the increased rate of land use. Rather they insisted on taking into account factors such as direct irradiance and wind speed to improve system performance.
“The full-scale outdoor experimental results of this study provide a reference for the design of photovoltaic power plants,” Shi explained. “The average relative error of the temperature prediction model of this study is only 5.4%, and that of the previous model is almost 20.0%. Thanks to the model of this study, the influence of environmental conditions and installation parameters on photovoltaic energy can be quantified more precisely.”
Their conclusions can be consulted in the study “ Surface temperature and power generation efficiency of PV arrays with various row spacings: A full-scale outdoor experimental study ” (Surface temperature and power generation efficiency of photovoltaic panels with various row spacings: a large-scale outdoor experimental study), published in Applied Energy . |
