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Maximise Your Savings with the SolarEdge Smart Hot Water Controller

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If you have an existing electric hot water system, such as a 250L hot water tank with a 3.6kW heating element, the SolarEdge Smart Hot Water Controller can significantly reduce your energy costs. By diverting excess solar energy to heat your water, this controller helps you minimise reliance on expensive grid electricity and off-peak tariffs. Here’s a detailed analysis of the potential savings you could achieve with this system.

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System Overview

• Existing Hot Water Tank Capacity: 250L
• Heating Element: 3.6kW
• Heating Rate: 62L/hour
• Off-Peak Tariff: $0.21 per kWh (used overnight)
• Feed-In Tariff: $0.05 per kWh (for excess solar energy)
• Continuous Tariff: $0.40 per kWh (used when solar is insufficient)
• Solar Heating Contribution: 97% of the time

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Energy Usage and Costs Without the Smart Hot Water Controller

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‍1. Standard Operation Using Off-Peak Electricity

• Energy Required to Heat the Tank:
  • To heat the full 250L from a typical starting temperature of 20°C to 60°C, the energy required is:
    • Energy Needed: Mass of Water (250L)×Specific Heat Capacity of Water×Temperature Rise\text{Mass of Water (250L)} \times \text{Specific Heat Capacity of Water} \times \text{Temperature Rise}Mass of Water (250L)×Specific Heat Capacity of Water×Temperature Rise
    • Energy Calculation:
      250 L×4.18 kJ/kg°C×(60°C−20°C)250 \, \text{L} \times 4.18 \, \text{kJ/kg°C} \times (60°C - 20°C)250L×4.18kJ/kg°C×(60°C−20°C)
    • Total Energy Required: 41,800 kJ (which converts to 11.6 kWh).
• Daily Cost of Heating (Off-Peak):
  • Cost: 11.6 kWh x $0.21/kWh = $2.44/day.
• Annual Cost Without Smart Hot Water Controller:
  • Total Annual Cost: $2.44/day x 365 = $890.60/year.

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Energy Usage and Costs with the SolarEdge Smart Hot Water Controller

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‍1. Using Excess Solar Energy for Heating

• Energy Provided by Solar (97% of the Time):
  • Solar Contribution: 11.6 kWh x 97% = 11.252 kWh/day.
• Cost of Using Solar Energy:
  • Opportunity Cost: If the excess solar energy were exported to the grid, it would earn $0.05/kWh.
  • Daily Cost of Using Solar: 11.252 kWh x $0.05/kWh = $0.56/day.
• Annual Cost of Using Solar:
  • Total Annual Cost: $0.56/day x 365 = $204.44/year.

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‍2. Using Grid Electricity When Solar Is Insufficient (3% of the Time)

• Energy Provided by Continuous Tariff (3% of the Time):
  • Grid Contribution: 11.6 kWh x 3% = 0.348 kWh/day.
• Cost of Using Continuous Tariff:
  • Daily Cost of Grid Usage: 0.348 kWh x $0.40/kWh = $0.14/day.
• Annual Cost of Using Continuous Tariff:
  • Total Annual Cost: $0.14/day x 365 = $51.10/year.

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‍3. Total Annual Cost with the SolarEdge Smart Hot Water Controller

• Total Annual Cost (Solar + Grid):
  • Total: $204.44/year (solar) + $51.10/year (grid) = $255.54/year.

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‍Net Financial Gain

• Annual Cost Without Controller (Off-Peak Only): $890.60/year.
• Annual Cost With Controller (Solar + Grid): $255.54/year.
• Net Savings: $890.60/year - $255.54/year = $635.06/year.

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‍Why Install the SolarEdge Smart Hot Water Controller?

• Maximised Solar Utilisation: Use your excess solar energy to heat water, reducing reliance on grid electricity and off-peak tariffs.
• Substantial Financial Savings: By using solar energy to heat your water, you can save up to $635.06/year on electricity costs.
• Energy Efficiency: Efficiently manage your energy use by prioritising solar power and only using grid electricity when absolutely necessary.
• Environmental Impact: Reduce your carbon footprint by making the most of renewable solar energy and minimising your dependence on fossil fuels.

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