Solar potential in urban residential buildings

• We evaluate the effect of shading on solar potential for building cluster.
• Increasing building aspect ratio will raise solar potential of the cluster.
• Building azimuth markedly affects PV yield rather than ST yield.
• Increasing site coverage will increase solar potential of the cluster.
• Low density cluster consisted of 6-story buildings will gain a net zero energy status.

This paper investigates solar potential in urban residential buildings at low, medium and high levels of site densities. The effects of three major design parameters (i.e. building aspect ratio, azimuth and site coverage) on solar potential are evaluated, respectively. Solar potential is measured, respectively, by photovoltaic (PV) and solar thermal (ST) yields per building floor space, taking into account the effect of irradiation threshold and incidence angle of the Sun’s rays. The results show that increasing building aspect ratio tends raise solar potential, and so does increasing site coverage. Additionally, there is a preferred range of building azimuth, under which PV yield remains at a higher level and out of which PV yield plummets. However, ST yield is affected modestly by building azimuth. This study also reveals that while mutual shadings may decrease PV yield by up to 50% and ST yield by up to 26% in the high-density scenario, it is still possible for PV and ST yields to meet annual electrical and thermal demands of residential buildings, respectively, by selecting appropriate design parameters. Most importantly, a promising result is observed that 6-story buildings in the low-density scenario can achieve net zero energy status when considering combined use of PV and ST.