CALORIFLC VALUE OF A FUEL VALORIFIC VALUE

In order to measure the energy available, from a fuel, it is necessary to use a laboratory CALORIMETER. Such a device enables a gram of liquid or solid fuel to be burned COMPLETELY in oxygen, whilst contained in a storage vessel (about the size of a 1kg jam jar). This vessel is submerged in water (with the water equivalent of the whole arrangement being 3kg) and a large - scale thermometer provides an accurate measure of the water temperature raise. This is usually about 4 degrees Celsius, for most hydrocarbon liquid fuels.

For gaseous fuels, a fuel-flow meter is used to measure a given volume of the gas, whilst a mass of water flows through the water jacket of a heat exchanger, in the, same interval of time. For solid or liquid fuels, the - Bomb - Calorimeter is often used, whereas the BOYS’ Calorimeter is useful for gases.

In each case, the energy absorbed by the water is said to be the converted chemical energy of the fuel and defined as the CALORIFIC VALUE OF THE FUEL. It is quoted in MJ/kg or MJ/M3.