The energy performance of building integrated photovoltaics (BIPV) by determination of optimal building envelope

Abstract

Building form and envelope surfaces play a significant role in energy performance assessment and the generated energy potential of the building integrated photovoltaics (BIPV) concept in early-stage design. To increase the energy efficiency level, form factor (FF) is proposed as a helpful tool that provides a strong relationship between the exposed surface areas and the treated floor area (TFA). This research aims to develop a methodology for a parametric study to determine the related balance between the TFA and the required BIPV area in the form enclosure to meet specific primary energy demand (SPED) according to the international Passive House standard (PHS). Therefore, various form types, including square, rectangle, L, and T shapes, derived from four modular cubes, are classified based on the same FF. Optimal form selection per group is conducted through BIPV potential evaluation for the exposed surfaces in six different orientations separately. Thereafter, the BIPV efficiency level for the optimized forms is examined using its utilization factor and coverage index scenarios based on the facade and roof combination priorities. The results indicate that the generated energy sufficiency is affected by the form configuration and its orientation. Additionally, the optimal BIPV-based FF value of 0.71 implies the priority of roof-based scenarios for less BIPV utilization. Finally, the correlation value for the BIPV coverage index relative to the total envelope for the optimal forms and orientation is higher than 0.92, which can be extended to other forms in different locations as an assessment model.