REKA A/S

Based on oil or natural gas

Boiler size: \(l-oil/year \over 268 \) or \(Nm^3-gas/year \over 235 \) = Boiler size

Example

Boiler size: \({4000 \ l-oil/year \over 268} \approx 15kW \) or \({4000 \ Nm^3-gas/year \over 235} \approx 17kW \)

Based on squaremeter and insulation

Boiler size: 6kW can heat 100m² or 0.06kW/m². (average insulation).

Example

Boiler size: \(5000m^2 * 0.06 \approx 300kW \)

2.3kg wood pellets or 2.7kg grain/woodchips, dry equals 1ltr heating oil

Wood pellets

Consumption: 4.9kWh/kg, 24 hours = 1 day, so 24kg wood pellets is required to heat 4.9kW/h in one day with 100% efficiency

Example

Consumption: 20kW boiler 100% efficiency \({20kW \over 4.9kW/kg } = 4.08kg/h \)

Consumption per day \({4.08kg/h * 24h } = 98kg/day \)

80% efficiency \({98kg \over 0.8 } = 123kg/day \)

90% efficiency \({98kg \over 0.9 } = 109kg/day \)

Consumption per day, for 20kW boiler with 100% efficiency.