The degree of utilisation of a boiler system is a quotient formed of the quantities of heat over a specific period (normally a year). In the case of a boiler system, this is the thermal energy used in relation to the thermal energy supplied by the fuel.
Formula for calculating the degree of utilisation
Degree of utilisation [%]
Cumulative thermal output of steam over the time [MWh]
Cumulative rated combustion input over time [MWh]
The degree of utilisation is a decisive parameter for the economic efficiency of the system as a whole. It encompasses all losses, i.e. losses that occur during downtimes, when starting up and shutting down the system, during load changes, during surface blowdown and bottom blowdown, in the pipework and containers (e.g. during thermal water treatment).
This important variable can however only be properly measured with heat meters at the consumers and fuel counters and is normally only actually recorded in comprehensive Energy Management Systems.