Impact of rooftop photovoltaic on energy demand of a building in a hot semi-arid climate

Abstract

Solar energy is one of the most abundant and widely available renewable energy sources. It can be harnessed using photovoltaic panels on top of buildings to reduce dependence on the electrical grid and to achieve the status of net-zero energy building. However, the rooftop coverage by solar panels can modify the heat interface between the roof surface and its surrounding environment. This can alter a building's energy demand for heating, ventilation, and air conditioning. Such an impact on a building's energy demand is highly correlated with its roof structure and climate. In this work, three-dimensional distributed thermal models of the bare and photovoltaic added rooftop ensembles are developed to simulate the heat gain/loss associated with the roof structure for monthly mean diurnal cycles. This work considers the low-rise, high-density building style and hot semi-arid climate of Faisalabad, Pakistan to quantify the impact of a rooftop photovoltaic on the roof-related thermal load of a building. Results depict a 42.58% reduced heat loss from the photovoltaic added roof structure during winter and a 1.98% increase in heat gain during summer. This reduces the electricity demand for indoor heating during winter and slightly increases it for indoor cooling during summer. The obtained results prove the significance of this work and provide guidelines to energy policymakers, the construction industry, and energy consumers. Moreover, this work provides a better understanding of the building's energy demand for heating, ventilation, and air conditioning with a rooftop photovoltaic system and its net-zero energy requirements, which are pivotal for modern construction.