Energy balance of mechanically ventilated photovoltaic double skin façade: A case study in summer
Xingjiang Liu, Jihong Pu, Chao Shen, Lin Lu
Abstract
• The mechanically ventilated photovoltaic double skin façade is studied in summer. • The forced airflow brings a better cooling effect, decreasing heat gain by 18.77 %. • The adoption of fans accompanies with at least 10 W of extra energy consumption. • It is summarized that limiting fan energy consumption may benefit its feasibility. • Four possible approaches are proposed and one of them is proved to be effective. Mechanical ventilation (MV) represents a promising solution to enhance the performance of photovoltaic double skin façade, whereas the trade-off issue between fans-consumed energy ( E fan ) and extra energy benefit remains a critical consideration. This study aims to assess the feasibility of MV during summer and provide insights into its effectiveness. Experimental investigations were conducted to compare the performance under natural and mechanical ventilation. The results indicate that MV enhances airflow and reduces indoor heat gain across the façade area by 18.77 %. However, the operation of fans introduces an additional electricity consumption of 10–15 W, partially offsetting the benefits of reduced heat gain. By summarizing the experiment results, an optimization framework of limiting E fan is proposed with four specific approaches, which are believed to reoptimize this trade-off issue and help achieve the feasibility of mechanical ventilation. As one of these four approaches, adjusting the cavity depth has been experimentally verified to improve the energy performance by about 4–7 %. This finding partly validates the effectiveness of the proposed optimization framework. In summary, this study highlights the potential of MV in reducing indoor heat gain and suggests avenues for optimizing its energy balance to achieve net energy gain.