OPJ: Origin data for Fig 3b.

In hot dry regions, photovoltaic modules are exposed to excessive temperatures, which leads to a drop in performance and the risk of overheating. The present numerical study aims to evaluate the natural air cooling of PV modules by an inclined chimney mounted at the back. The basic equations were solved using the finite volume method. The validity of the model is verified by comparison with the data available in the literature. Thermal and dynamic flow patterns are analyzed for a variety of parameters: Rayleigh numbers from 102 to 106, PV panel tilt angle from 15° to 90°, and channel aspect ratios from 1/20 to 1/5. A critical aspect ratio has been determined to minimize overheating of the PV module. According to the computational results, the tilt angle and modified Rayleigh number increase the mass flow rate and mean Nusselt number. The overheating zone with maximum temperatures is located in the upper part of the photovoltaic panel. The addition of an extension to both channel’s inlet and outlet was found to improve the cooling of the photovoltaic panels; however, only the extensions downstream of the channel are truly effective. The critical lengths at which channel performance improves significantly were identified by examining the impact of longer extensions on channel performance. Increasing the extension length from 0 to 3H improves the mass flow rate by 65%, the average Nusselt number by 13.4%, and leads to an 11% decrease in maximum temperature when Ra* = 106. This cooling technique is particularly promising for hot dry regions where water is scarce.

在炎热干旱地区，光伏组件（photovoltaic module）长期处于过高温度环境中，会导致其性能下降并伴随过热风险。本数值模拟研究旨在评估安装于光伏组件背部的倾斜式烟囱对其开展的自然风冷效果。本研究采用有限体积法（Finite Volume Method）求解控制方程组，并通过与公开文献数据对比，验证了所建数值模型的有效性。针对多组参数开展流场与热场分布分析，涉及参数包括：瑞利数（Rayleigh Number）范围10²至10⁶、光伏面板倾角范围15°至90°，以及通道纵横比范围1/20至1/5。研究确定了可使光伏组件过热程度降至最低的临界通道纵横比。模拟结果显示，光伏面板倾角与修正瑞利数（modified Rayleigh Number）的增大，会提升质量流量与平均努塞尔数（Nusselt Number）。温度最高的过热区域集中于光伏面板的上部区域。在通道入口与出口处增设延伸段均可改善光伏面板的冷却效果，但仅通道下游侧的延伸段可实现真正的降温增效。通过探究更长延伸段对通道换热性能的影响，研究确定了可使通道性能实现显著提升的临界延伸长度。当修正瑞利数Ra*=10⁶时，将延伸段长度从0提升至3H，可使质量流量提升65%、平均努塞尔数提升13.4%，并使最高温度降低11%。该自然风冷技术在水资源匮乏的炎热干旱地区极具应用前景。