Question 6.2: We have the following data: 1 toe = 42 GJ = 11.6 MWh. The co......
We have the following data: 1 toe = 42 GJ = 11.6 MWh. The combustion of 1 toe gives 3.7 tons of \mathbf{CO}_{2} . One ton of dry wood equals 5.22 MWh. Since there is space between the pieces of wood, the volume corresponding to 1 ton is about 2 m³. Assume an oil-fired boiler has an efficiency of 80% and a wood-fired boiler has an efficiency of 75%. Consider a house of 150 m² needing 100 kWh/m² /year for heating. Calculate the quantity of oil needed and the \mathbf{CO}_{2} emissions per year. Calculate the same quantities for wood.
To heat the house 15,000 kWh/year is needed. This corresponds to almost 1.3 tons of fuel (≈1.8 – 1.9 m³) or 2.9 tons of dry wood (5.8 m³). The quantity of \mathbf{CO}_{2} emitted is 4.8 tons. In the case of wood, most of the \mathbf{CO}_{2} has been previously absorbed from the atmosphere when the trees were growing. For oil there is not this balance.