Extract

As a result of the increasing adoption of rooftop solar photovoltaic (PV) systems in homes and the mismatch between peak residential load and peak harvested solar energy, a considerable percentage of harvested energy fails to be consumed in homes, resulting in low PV self-consumption. This is further compounded by recent rules and limits, which control how much of the excess PV power can be exported back to the electrical grid and may also force some available solar energy to remain unharvested. To address these issues, a combined system is proposed in which a polyvalent heat pump coupled with water storage tanks produces and stores hot and cold water by using PV power for heating, cooling, and domestic hot water use. Annual hourly thermal loads for heating and cooling of a typical Australian house located in Geelong, Victoria, are determined using TRNSYS. The house’s annual hourly electricity consumption is calculated based on energy data, measured with a smart meter, and harvested solar energy, measured with a PV system controller. Results show that by working with relevant setpoint temperatures of water tanks and control strategies of the polyvalent heat pump, the proposed combined system reduced the annual grid energy demand by about 28%. In addition, the PV self-consumption and self-sufficiency were increased to 31.39% and 64.57%, respectively. This study demonstrated that this proposed combined system could effectively increase the PV self-consumption and self-sufficiency and reduce the grid electricity use of the house, thus reducing the burden on the electrical network.

Keywords: Solar PV; self-consumption; heat pump; water storage tanks.

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