Non-uniformity of convective heat transfer coefficients in photovoltaic arrays: a wind tunnel experimental study
Yunyun Wen, Xingcai Li, Juan Wang
Abstract
Effective thermal management remains a critical challenge for photovoltaic (PV) systems, as excessive temperature rise under high irradiance significantly reduces power conversion efficiency. This study presents the first systematic experimental investigation of convective heat transfer characteristics in multi-module PV arrays through controlled wind tunnel tests, addressing a critical gap in existing literature that predominantly focuses on single-module analysis. A comprehensive parametric study quantifies the effects of aerodynamic conditions and geometric configurations on heat transfer performance. Key findings reveal significant non-uniformity in convective heat transfer coefficients across the array: the first, third, and fourth modules exhibit stronger heat exchange at their edges but weaker performance in central regions, while the second module shows larger fluctuations and overall lower coefficients. A strong linear correlation exists between convective heat transfer coefficients and wind speed—when wind speed increased from 4 m/s to 12 m/s, the average coefficients of the four modules rose by +148.9 %, +220.5 %, +141.6 %, and +222.7 %, respectively. Wind incidence angle critically influences thermal performance, with optimal dissipation at 90°, where the heat transfer coefficient increased by 161.9 %. Additionally, peak convective heat transfer occurs at installation angles of 15° and 60°, identifying these as optimal for thermal regulation. The interplay between array spacing and ground clearance further underscores the need for holistic PV system design optimization. These findings provide theoretical and practical insights for enhancing PV performance through improved thermal management strategies.