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Save on Gas Bills with Our Energy-to-Heat Storage Product

If you already have a 6kW solar power system and are using a gas instant hot water system, you could be missing out on significant savings. Our innovative 160L energy-to-heat storage tank with a 2.4kW heating element can help you reduce your gas consumption by utilising excess solar energy to preheat your water. Here’s how it works and the potential savings you can achieve.

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How the System Works

1. Energy Diversion: Instead of exporting excess solar energy to the grid, you divert it to heat your 160L tank. The tank’s 2.4kW element heats water at a rate of 40L per hour with a 45°C temperature rise.
2. Preheating for Gas Efficiency: The hot water outlet from the tank is connected to the cold inlet of your gas instant hot water system. This means that when the water entering the gas unit is already preheated:
   • If the water temperature is above 50°C, the gas burner won’t ignite, saving you gas entirely.
   • If the water is around 30°C, the gas burner will ignite only briefly, using far less gas to reach the desired temperature.
3. Year-Round Savings: Solar PV production varies throughout the year, but even during lower production periods, the system still reduces gas consumption by preheating the water.

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System Specifications

• Tank Capacity: 160L
• Heating Element: 2.4kW
• Heating Rate: 40L per hour at a 45°C temperature rise

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Potential Savings Analysis

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1. Maximising Solar Energy Use

• Daily Solar Generation (6kW system): Approximately 25.2 kWh/day (average).
• Excess Solar Energy: Assuming 30% self-consumption, you have around 17.64 kWh/day of excess energy.
• Energy to Heat the Tank: The tank uses 2.4kW per hour to heat 40L of water. To heat the full 160L, it requires 4 hours, consuming a total of 9.6kWh of electricity.

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2. Gas Usage for Showers (Without the Tank)

• Water Heating Requirement:
  • For a 38°C shower temperature and 50°C water from the gas unit, the required rise is (50°C - 15°C inlet temperature) = 35°C.
• Gas Consumption for Heating:
  • Flow Rate: 9L/min x 6 minutes = 54L per shower.
  • Total Water Usage for 3 Showers: 54L x 3 people = 162L/day.
  • To heat this water from 15°C to 50°C, the gas unit operates at a 35°C rise.

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Gas Usage Calculation:

• Gas Consumption per Shower:
  • Instant gas units consume 120 MJ/h at a 25°C rise for 18L/min. For a 35°C rise, it would consume proportionally more energy.
  • Approximate Gas Usage:
    120 MJ/h18 L/min×9 L/min×3525×6 minutes=20.09 MJ per shower\frac{120 \, \text{MJ/h}}{18 \, \text{L/min}} \times 9 \, \text{L/min} \times \frac{35}{25} \times 6 \, \text{minutes} = 20.09 \, \text{MJ per shower}18L/min120MJ/h​×9L/min×2535​×6minutes=20.09MJ per shower.
  • Daily Gas Usage: 20.09 MJ/shower x 3 showers = 60.27 MJ/day.

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Cost Without Tank:

• Gas Cost: 60.27 MJ/day x $0.035/MJ = $2.11/day.
• Annual Gas Cost: $2.11/day x 365 = $770.15/year.

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3. Gas Savings with the Tank

• Preheated Water: If the 160L tank preheats water to 50°C or close, the gas unit’s consumption could be significantly reduced or eliminated.
• Daily Tank Heating: Using 9.6 kWh of solar energy, the tank can potentially replace a significant portion of the energy needed to heat water using gas.
• Gas Usage Reduction: With the tank, the gas unit may not need to operate at all or only minimally to maintain the desired temperature.

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Cost With Tank:

• Electricity Cost: The tank uses solar energy, which would otherwise be sold back to the grid at $0.05/kWh.
• Daily Electricity Cost: 9.6 kWh x $0.05 = $0.48/day (opportunity cost of not exporting the solar energy).
• Annual Electricity Cost: $0.48/day x 365 = $175.20/year.

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Net Savings:

• Annual Gas Savings: $770.15/year (gas cost without tank).
• Annual Electricity Cost (using solar energy): $175.20/year.
• Net Savings: $770.15/year - $175.20/year = $594.95/year in savings.

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Why Choose Our Energy-to-Heat Storage Product?

• Maximised Solar Utilisation: Divert excess solar energy to heat water instead of selling it back to the grid at a low feed-in tariff, resulting in higher savings.
• Substantial Gas Savings: By preheating your water, you can save up to $594.95/year on gas bills.
• Increased Energy Efficiency: Use free solar energy to reduce or eliminate gas consumption for your daily hot water needs.
• Environmental Impact: Lower your carbon footprint by reducing reliance on fossil fuels and maximising renewable energy use.

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Ready to Start Saving? Find out exactly how much you can save by integrating our energy-to-heat storage product with your existing solar system. Try our AI Home Energy Analyser to discover the perfect solution tailored to your needs!

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