Numerical study on convective heat transfer characteristics of photovoltaic arrays and the covered flat roof surfaces

The convective heat transfer coefficient at photovoltaic panel surfaces is critical for predicting power output performance. Due to wind-shielding effects, airflow and the convective heat transfer coefficient vary across photovoltaic array regions. This study develops a three-dimensional heat transfer model to systematically analyze the influence of photovoltaic layout parameters on the convective heat transfer coefficient. Results demonstrate that installing photovoltaic arrays reduces the local convective heat transfer coefficient on the roof and causes significant differences in heat exchange characteristics between first-row and rear-row photovoltaic panels. The effects of photovoltaic panel size and array row spacing on the convective heat transfer coefficient are minimal. When the tilt angle of the photovoltaic panel increases, the convective heat transfer coefficient between roof and first-row photovoltaic panel rises by 55.72% and that between air and the roof increases by 19.94%, while the convective heat transfer coefficient for rear-row panels decreases. Increasing the installation height doubles the convective heat transfer coefficient for the first-row panel and raises that for rear-row panels by 18.97%, but weakens the heat exchange between the roof and the panels. Increasing the array setback distance decreases the convective heat transfer coefficient for the first-row panel by 25.04% and increases that for the roof by 19.80%.