Performance investigation of transitioning building services system in photovoltaic homes

Abstract

Growing concern over residential carbon emissions has highlighted the necessity of transitioning conventional fossil fuel-based building services system into one that utilizes renewable energy sources. Therefore, this paper proposes a building services system, including an air-source heat pump, water storage tanks and batteries, for photovoltaic (PV) homes so that all their energy loads are electrified and mostly met by PV power. It aims to investigate the merits of the proposed system in relation to energy, economic and environmental performance by designing three distinct scenarios for power supply, space heating, space cooling, and domestic hot water (DHW). A typical Australian house equipped with a 10 kW solar PV system in Geelong, Victoria, is used as a case study. Three scenarios are modelled using Transient System Simulation (TRNSYS) software, and the simulated PV generation, space heating, and DHW load are validated using actual measured results. Findings show that the proposed system offsets all the natural gas demand of 6915 kWh required by Scenario 1 using the conventional fossil fuel-based system and increases the PV self-consumption and self-sufficiency from 18 % to 24 % in Scenario 1–38 % and 75 %, respectively. After adjusting component sizes following the principle of diminishing returns, the proposed system has a nine-year payback period and reduces carbon emissions by 67 % compared to the conventional system. This study demonstrates the capability of the proposed system to electrify our house loads, thus contributing to a decarbonized residential future.