Solar cities: Multiple-reflection within urban canyons

Abstract

Solar photovoltaic (PV) harvesting is a significant energy resource leading to the rapid expansion of renewable energy. To facilitate decision-making regarding the optimal location and appropriate time for harvesting solar energy, the precise estimation of solar potential distribution in a city especially in 3D context is essential. However, using constant values to represent the urban vertical façades in a city and/or ignoring the indirect components under the estimation of received irradiation have been adopting in the current research, which may lead to inaccuracies in final results particular in complex urban environment. In this work, we propose a methodology to estimate the solar potential accurately by incorporating the façade albedo using street view images, as well as considering multiple reflection in urban canyon. Furthermore, this method is further integrated in the proposed evaluation framework to assess the impact of urban façade albedo on solar potential distribution. Compared to existing methods, the proposed framework first discusses and analyzes the importance of façade albedo and evaluates its impact quantitatively. The experimental results show that the discrepancies in albedo significantly affect the overall solar potential by 8.0% to 9.1%. If multiple reflections under urban canyon are disregarded, the impact can reach 11.9% to 17.8%.