Figure 9
Four graphs are presented in a 2 by 2 grid. On the top left, the graph is labeled “(a) Hourly energy summary one of the two simulations”. The left vertical axis is labeled “Exported energy in kilowatt hours slash Imported energy in kilowatt hours”, ranging from negative 12 to 12 in increments of 3. The right vertical axis is labeled “State of charge of batteries”, ranging from 0.0 to 1.0 in increments of 0.2. The horizontal axis is labeled “Hour”, ranging from 0 to 24 in increments of 2. The “P V energy” curve begins at (0, 0.000), peaks at (12, 9.500), and ends at (24, 0.000). The “State of charge of batteries” curve begins at (0, 0.300), peaks at (14, 1.000), and ends at (24, 0.200). Simulation 1 and Simulation 2 bars are negative between 8 and 18 hours. On the top right, the graph is labeled “(b) Hourly energy summary two of the two simulations”. The vertical axis is labeled “Heat pump energy use in kilowatt hours”, ranging from 0.0 to 2.5 in increments of 0.5. The vertical axis on the right is labeled “Heating element energy use in kilowatt hours”, ranging from 0.0 to 2.5 in increments of 0.5. The horizontal axis is labeled “Hour”, ranging from 0 to 24 in increments of 2. The “Heating element energy use” curve begins at (0, 0.000), peaks at (8, 2.000), and ends at (24, 0.000). Simulation 1 is higher compared to Simulation 2 bars. On the bottom left, the graph is labeled “(c) Average tank temperature and hourly D H W load of the two simulations”. The vertical axis is labeled “Average tank temperature in degrees Celsius”, ranging from 0 to 80 in increments of 20. The vertical axis on the right is labeled “D H W load in kilowatt hours”, ranging from 0.0 to 3.0 in increments of 0.5. The horizontal axis is labeled “Hour”, ranging from 0 to 24 in increments of 2. The “Simulation 1” curve begins at (0, 58.000), peaks at (14, 59.500), and ends at (24, 56.000). The “Simulation 2” curve begins at (0, 65.000), peaks at (11, 69.000), and ends at (24, 65.000). On the bottom right, the graph is labeled “(d) Total electrical load of the house in the two simulations”. The vertical axis is labeled “Total electrical load of the house in kilowatt hours”, ranging from 0 to 4 in increments of 1. The horizontal axis is labeled “Hour”, ranging from 0 to 24 in increments of 2. The “Simulation 2” bar begins at (0, 1.000), peaks at (16, 2.800), and ends at (24, 1.000). The “Simulation 2” bar begins at (0, 1.000), peaks at (16, 2.300), and ends at (24, 1.000). Note: All numerical data values are approximated.Hourly energy summary of the two simulations featuring the large DHW and high electrical load profiles on the peak PV generation day (04 January) of summer: Simulation 1 has no heating element or batteries, and Simulation 2 has a 10 kWh battery and a heating element with the output capacity of 2.5 kW and the threshold of 5 kW. Source: Authors' own work