Compute thermal efficiency as useful output divided by energy input, with losses and the fuel cost per unit of useful energy.
η = 有效输出 / 能量输入。
| Item | Formula / Rule | Source / Standard |
|---|---|---|
| Efficiency formula | η = useful heat output / heat input × 100%. | ISO 80000-5:2019, thermodynamic quantities and units |
| Boiler thermal test | Boiler thermal efficiency is measured by the prescribed thermal performance test method. | GB/T 10180-2017, thermal performance test code for industrial boilers |
| Calorific basis | Efficiency calculation must state whether gross or net calorific value is used as the basis. | GB/T 10180-2017 & ISO 1928:2009 |