Explanation of Calculations
The daily running cost is calculated using the following formula:
Daily Cost = Heater Size (kW) * Hours per Day * Duty Cycle * Cost per kWh * Power Factor
Where:
- Duty Cycle is assumed to be 30% (0.3)
- Power Factor is 1 for electricity, and calculated for firewood and pellets based on their efficiency and energy content
Assumptions:
- Heater duty cycle: 30% (heater runs at full capacity 30% of the time)
- Firewood:
- Heater efficiency: 60%
- Energy content: 4.5 kWh/kg
- Pellets:
- Heater efficiency: 80%
- Energy content: 4.8 kWh/kg
- Heat Pump:
- Coefficient of Performance (COP): 2.5