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Actual seasonal efficiency

The actual seasonal efficiency of a boiler system is a ratio formed from heat quantities over a specific period (usually one year). For a hot water boiler system, this is the thermal energy used in relation to the heating energy supplied by the fuel.

Unlike the standard efficiency, the seasonal efficiency is generated from existing measured values and therefore reflects the benefit achieved under real conditions for a specific period of time.

$Seasonal efficiency η = \frac{Output energy}{Input energy}$

Formula for calculating the seasonal efficiency

$η = \frac{\int \overset{\cdot}{Q} d t}{\int {\overset{\cdot}{Q}}_{F} d t}$

ƞ	Seasonal efficiency [%]
$\int \overset{\cdot}{Q} d t$	Total heat output over time [MWh]
$\int {\overset{\cdot}{Q}}_{F} d t$	Total rated heat input over time [MWh]

The actual seasonal efficiency is the key indicator for the economic efficiency of the entire system at a given location. It includes all losses, i.e. losses incurred during standstill, when starting up and shutting down the system, during load changes, at different flow and return temperatures, as well as heat losses in the pipes and valves.

However, this important variable can only be measured accurately using heat meters at the point of consumption and fuel meters, and is usually recorded as part of a comprehensive energy management system.

Go back to "Standard efficiency"

Go on to "Annual efficiency"