Effect of adjacent shading on the energy and environmental performance of photovoltaic glazing system in building application

Abstract

Photovoltaic (PV) system is a commonly adopted renewable energy system in building application. In most of the assessments on PV system, there is no consideration on adjacent shading effect cast by surrounding buildings which may lead to over-estimation of PV energy generation and inaccurate calculation of energy payback time (EPBT). This paper investigates the effect of adjacent shading on energy generation and EPBT of PV system. A survey had been conducted to identify and select 25 existing commercial buildings with different degrees of adjacent shading (expressed in terms of sky view factors (SVF), ranging from 0.16 to 0.95) and orientations. Through computer simulations using EnergyPlus, it reveals the significance of adjacent shading effect on the PV energy generation as well as EPBT of building-integrated PV glazing system for the 25 selected buildings, in terms of two ratios, namely PV electricity energy ratio (0.18–0.84) and energy payback time ratio (1.17–5.74). Moreover, a correlation between SVF and PV electricity energy ratio was established (PVEE Ratio = 0.3867 SVF2 + 0.4176 SVF + 0.0975) with which building professionals can evaluate the PV energy generated and EPBT of a building-integrated PV glazing system in building application, under adjacent shading effect.