Performance of office building integrated photovoltaic for windows under semi-arid climate in Algeria

Abstract

Building integrated photovoltaic (BIPV) has become the most significant alternative form of renewable energy for producing clean energy and to protect the environment. In Algeria, some problems arise due to the high energy consumption levels of building sector. Large amounts of this energy are lost through the external envelope façade, because of poor window design. Therefore, this research aimed to investigate the optimum BIPV windows performance for overall energy consumption (OEC) in typical office buildings in the semi-arid climate. Field measurements on a tested office building were carried out during the spring and summer seasons for the calibration and validation of Energy-plus and Integrated Environment Solution Virtual Environment (IES-VE) software. The data was analysed and used to develop a model for (OEC) simulation. The results of the investigation from the site measurements show that the BIPV window application provides a sufficient quantity of uniform daylight with only 20% Visible Light Transmittance (VLT), plus a comfortable indoor temperature and a considerable amount of clean energy production. The base-model and nine commercially-available BIPV modules, with different Window Wall Ratio (WWR), cardinal orientation and tilt angles were applied in an extensive simulation exercise. The simulation was carried out using Energy-plus to evaluate the energy generated through simple and equivalent one-diode models. The thermal performance used the Ideal load Air System (ILAS) model. In addition to IES-VE for the assessment of visual comfort and daylighting performance, through a combination of daylight control method, Useful Daylight Illuminance (UDI) and CEI glare index (CGI) were done. The results from this study revealed that the optimum BIPV window design differentiates in each orientation; which is the double glazing PV modules (A) with medium WWR and 20% VLT in the Southern facade, 30% VLT toward the East-West axis. Meanwhile, the North orientation is not suitable the application of BIPV window. The Maximum energy saving can be obtained with a 60% toward the South orientation by double glazing PV module (D). On the other hand, the PV modules minimize significantly the glare index comparing the base-model. The result established that the energy output percentages in a 3D model can be used by architects and designers in the early stages of design. Thus, the adoption of optimum BIPV window shows a significant improvement of the overall energy saving and visual comfort to deem them as an essential application in the semi-arid climate.