(HVAC) Combustion efficiency is a measure of the heating efficiency of a boiler. That is, it is a measure of the number of units of input energy required to produce a unit of output heat. The combustion efficiency of a boiler is measured once the boiler is up and running (at steady state). This makes combustion efficiency a less accurate measurement of the overall efficiency of a boiler than the AFUE which takes into account the boiler (or furnace's) efficiency as it cycles through startup and shutdown.
The effectiveness of the burner to completely burn the fuel. A well designed burner will operate with as little as 10 to 20% excess air, while converting all combustibles in the fuel to useful energy.
The amount of heat usefully available divided by the maximum amount which can be liberated by combustion; usually expressed in percentage.
A measure of useful heat extracted from a fuel source by an operating heating appliance. For example a furnace with a combustion efficiency of 60 percent converts 60 percent of the fuels energy content into useful heat. The rest is lost as exhaust gases.
Defined as the energy input minus stack loss, divided by the energy input. Sometimes referred to as thermal efficiency.
The relative amount of time a fire burns in the flaming phase of combustion, as compared to smoldering combustion. A ratio of the amount of fuel that is consumed in flaming combustion compared to the amount of fuel consumed during the smoldering phase, in which more of the fuel material is emitted as smoke particles because it is not turned into carbon dioxide and water.
actual heat produced by combustion total heat potential of the fuel consumed
The efficiency of converting available chemical energy in the fuel to heat. It measures only the completeness of fuel combustion that occurs in the combustion chamber.
Ratio of the heat released in combustion to the heat available from the fuel.
a measurement (in percent) of how well heating equipment converts fuel into useable heat energy. Complete combustion efficiency (100%) would extract all the energy available in the fuel, though this not realistically achievable due to stack loss and boiler shell losses. Combustion efficiency calculations assume complete fuel combustion and the following three factors: The chemistry of the fuel (the proportions of hydrogen, carbon, oxygen and other compounds) and how much energy is chemically bound in the fuel. The net temperature of the stack gases or how much heat is not being used. The percentage of oxygen (O2) or carbon dioxide (CO2) by volume after the combustion process or how much O2 did the fuel completely burn.
The fraction of carbon in the fuel that is converted into CO2 in the flue gas, customarily expressed as a percent.
