Experimental Study on Energy Efficiency of Multi-Functional BIPV Glazed Façade Structure during Heating Season

Abstract

Building integrated photovoltaics (BIPV) is technology that can significantly increase the share of renewable energy in final energy supply and are one of essential technologies for the nearly zero-energy buildings (nZEB), new build and refurbished. In the article (a) an experimental semitransparent BIPV glazed façade structure with 60% of PV cell coverage is shown; (b) energy efficiency indicators were developed based on identified impact parameters using experimental data; and (c) multi-parametric models of electricity generation, preheating of air for space ventilation, and dynamic thermal insulation features that enable prediction of solar energy utilization in different climate conditions are shown. The modeled efficiency of electricity production of BIPV was in the range between 8% and 9.5% at daily solar radiation above 1500 Wh/day, while low impact of outdoor air temperature and ventilation air flow rate on PV cell cooling was noticed. Between 35% and 75% of daily solar radiation can be utilized by preheating the air for space ventilation, and 4.5% to 7.5% of daily solar radiation can be utilized in the form of heat gains through opaque envelope walls.

Current prospects of building-integrated solar PV systems and the application of bifacial PVs

“…The predicted BIPV efficiency of electricity production was found between 8% and 9.5%, with no effect of outdoor air temperature and ventilation airflow rate on PV module cooling. A total of 7.5%-4.5% of daily solar radiation can be used as heat gains through opaque envelope walls, and between 75% and 35% of daily solar radiation can be used to pre-heat the air for space ventilation (Domjan et al, 2020).…”

Contribution of energy storage to the transition from net zero to zero energy buildings

“…The impact of the spacers and frames was modelled by adequate opaque structures with a thermal transmittance of U 0.02 W/m 2 K. The south facade is built with six-pane glazed BIPV structures with PV cells integrated into the outer glass pane with a thickness of 2 × 4 mm. A PV cell packing factor of 60% was chosen because it was found as optimal according to the heating, cooling, and daylighting energy needs [30,31]. The areas of BIPV structures were determined for each of the observed climate conditions in the way that yearly energy balance (imported/produced/used/exported) of the gridconnected building, is zero with tolerance ±4% of yearly final energy balance.…”

Dynamic parametric models for the holistic evaluation of semi-transparent photovoltaic/thermal façade with latent storage inserts

“…Meteorological parameters were measured in parallel with a Vantage Pro 2 weather station installed on the top of the test building. The experimental setup is presented in detail in [34].…”

“…The review and validation of several simplified and detailed BIPV thermal models, presented in [33], show good agreement of numerical and experimental results, including for linear regression models with solar radiation as the only independent variable. Empirical models for diurnal solar energy utilization by BIPV, preheating of the ventilation air, and heat gains of the façade wall are developed by Domjan et al [34]. The statistical indicators of the Normalized Mean Bias Error (NMBE) of 2.4% and 1.4% were obtained for the developed models.…”