Abstract
Performance of solar PV diminishes with the increase in temperature of the solar modules. Therefore, to further facilitate the reduction in cost of photovoltaic energy, new approaches to limit module temperature increase in natural ambient conditions should be explored. Thus far only approaches based at the individual panel level have been investigated, while the more complex, systems approach remains unexplored. Here, we perform the first wind tunnel scaled solar farm experiments to investigate the potential for temperature reduction through system-level flow enhancement. The percentage of solar irradiance converted into electric power depends upon module efficiency, typically less than 20%. The remaining 80% of solar irradiance is converted into heat, and thus improved heat removal becomes an important factor in increasing performance. Here, We investigate the impact of module inclination on system-level flow and the convective heat transfer coefficient. Results indicate that significant changes in the convective heat transfer coefficient are possible, based on wind direction, wind speed, and module inclination. We show that 30–45% increases in convection are possible through an array-flow informed approach to layout design, leading to a potential overall power increase of ~5% and decrease of solar panel degradation by +0.3%/year. The proposed method promises to augment performance without abandoning current PV panel designs, allowing for practical adoption into the existing industry. Previous models demonstrating the sensitivity to convection are validated through the wind tunnel results, and a new conceptual framework is provided that can lead to new means of solar PV array optimization.
Highlights
Performance of solar PV diminishes with the increase in temperature of the solar modules
Our experimental results show that the sensitivity to wind direction and module inclination angle is significant, with a 45% increase in convective heat transfer coefficient possible, depending on the incoming wind direction
For sites with low wind speeds over much of the year, this research suggests further examination to determine if the buoyant currents generated by the heated air above the panels themselves could be harnessed to increased mixing and flow through the solar farm
Summary
Performance of solar PV diminishes with the increase in temperature of the solar modules. The experimental platform introduced in this work provides for the first time the opportunity to shift the focus from the individual panel to the array Through this new lens, we examine the fluid flow and heat transfer in a large scaled solar array, beginning with fundamental parameters of inclination angle and wind speed. The present study provides an opportunity for future work by examining the key parameters that govern heat transfer in large solar farms and informing improved layout designs[19] This approach to temperature reduction is attractive as it is passive, and does not require costly new technology developments or maintenance. Our experimental results show that the sensitivity to wind direction and module inclination angle is significant, with a 45% increase in convective heat transfer coefficient possible, depending on the incoming wind direction These changes can be directly correlated to changes in the flow field through the farm. This experimental platform allowed us to explore a question that was previously impractical to answer at full scale and identify the highest reward paths to PV farm layout optimization for lower operating temperatures
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