GB/T 27724-2011 "Calculation method of energy balance and energy efficiency for ordinary fourdrinier paper machine system" stipulates the calculation method for energy balance and the evaluation indicators for energy efficiency in ordinary fourdrinier paper machine systems. It is applicable to various types of ordinary fourdrinier paper machine production lines. The standard defines the system boundary to include the paper machine itself and supporting units such as the wire section, press section, and drying section. It standardizes the calculation of energy inputs, such as electricity, steam, and compressed air, as well as outputs, including energy carried by finished paper and heat dissipation losses. Additionally, it specifies the method for calculating energy efficiency, providing data support for optimizing energy consumption in paper machines.