Investigation of the performance enhancement of building-integrated photovoltaic system using evaporative porous clay applied in different building's directions

Abstract

The integration of photovoltaic (PV) modules with building's facades and roofs results in significant reduction in the PV module's efficiency owing to its temperature rising, as well as increasing in the building's indoor thermal gain. Thus, this study proposed cost-effective and eco-friendly passive cooling technique utilizing evaporative porous clay material to minimize the integrated PV module's temperature. An experimentally validated numerical study is being performed using different clay thickness and porosity to estimate the expected enhancement in the thermal and electrical performance of the building-integrated photovoltaic (BIPV) system. The experimental tests were carried out using prototype of small rooms integrated with PV panels installed with a water-saturated porous clay material to validate the presented transient numerical heat and mass transfer model. After that, the proposed system is being compared with another passive cooling mechanism using phase change material (PCM), and the results are then analyzed and compared. The findings showed a maximum reduction of 19.1 °C and 12.8 °C of peak PV temperature when the porous clay and PCM are utilized, while the building's side temperature reduced by around 11.2 °C and 10.9 °C, respectively. Further, porous clay achieved up to 9.8 % improvement in PV system's efficiency, with a maximum water consumption rate reached around 3.35 L/h.m2. Moreover, applying such a porous clay cooling approach resulted in a maximum reduction of 53.8 % in the building's annual thermal load. In the outcomes reported here, porous clay with the least thickness and highest porosity achieved more feasible cooling effects compared with PCM.