La Nordica Gemma Liberty [21/48] Calculation of the thermal power

GEMMA - GEMMA FORNO

7191601 - IT - EN - DE - FR 21

13. CALCULATION OF THE THERMAL POWER

There is not an absolute rule for calculating the correct necessary power. This power is given according to the space to be heated, but it

depends also largely on the insulation. On an average, the caloric value necessary for a properly insulated room is 30 kcal/h per m

(for

an external temperature of 0°C).

Given that 1 kW corresponds to 860 kcal/h, it is possible to adopt a value of 38 W/m

Let’s suppose one wishes to heat a room of 150 m

(10 x 6 x 2.5 m) in an insulated apartment. In this case, it is necessary to have 150 m

x 38 W/m

= 5700 W or 5,7 kW. As main heating, a 8 kW device is therefore sufcient.

Approximate combustion value Required quantity in relation to 1 kg of dry

wood

Fuel Unit kcal/h kW

Dry wood (15% humidity) kg 3600 4.2 1,00

Wet wood (50% humidity) kg 1850 2.2 1,95

Wood briquettes kg 4000 5.0 0,84

Brown coal briquettes kg 4800 5.6 0,75

Normal anthracite kg 7700 8.9 0,47

Coke kg 6780 7.9 0,53

Natural gas m

7800 9.1 0,46

Naphtha L 8500 9.9 0,42

Electricity kW/h 860 1.0 4,19