The lower heating value (also called energy value, or heat of combustion, or calorific value) is the energy (heat) produced by the combustion of the fuel/material without condensation of the flue gas.
| Fuel | Energy value [MJ/kg] | Energy value [kWh/kg] | Density [kg/litre] | Energy value [kWh/litre] |
|---|---|---|---|---|
| Diesel fuel | 44,4 | 12,33 | 0,835 | 10,30 |
| Gas (benzine) | 43,6 | 12,11 | 0,68 | 8,24 |
| LPG | 46,1 | 12,81 | 0,52 | 6,66 |
| Methane | 52 | 14,44 | 0,656 | 9,48 |
| Coal (coke) | 29,6 | 8,22 | 2 | 16,44 |
| Charcoal (from wood) | 31,5 | 8,75 | 0,4 | 3,50 |
| Dry wood | 17 | 4,72 | 0,8 | 3,78 |
| Hydrogen | 130 | 36,11 | 0,0899 | 3,25 |
| Sugar | 17 | 4,72 | 1,6 | 7,56 |
| Peanut butter | 24,6 | 6,83 | 00.08.00 | 0,04 |
| Seed oil | 37 | 10,28 | 0,92 | 9,46 |
| Butter | 30 | 8,33 | 0,92 | 7,67 |
Wood’s energy value varies maximum 15% between different types of wood.
Converting the value to other units
To change the unit of measurement, just multiply the starting value by the unit factor FU = 1, to eliminate the unwanted part of the initial unit of measurement. If necessary, use the inverse (1 / FU), which is still 1.
1 = 1 kWh / 3.6 MJ
1 = 4.186 kJ / 1 kcal
Example 1: We want to convert 10 kWh into Joules
10 kWh * (3.6 MJ / 1 kWh). = 36 MJ.
Note how kWh in the numerator and kWh in the denominator cancel out.
Example 2: we want to convert 1 kWh into kcal
1 kWh * (3.6 MJ / 1 kWh) * (1000 kJ / 1 MJ) * (1 kcal / 4.186 kJ) = 1 * 3.6 * 1000 * 1 / 4.186 = 860 kcal.
Note how the unit factor also works well for changing the unit prefix (from MJ to kJ in this case).
We just found a new unit factor!
1 = 860 kcal / 1 kWh. (or 1 = 1 kWh / 860 kcal)