Understanding thermal transfer mechanisms in BOF converter is akey for higher energy efficiency, involving higher production capacityand lower CO2 emissions through low hot metal ratio capability.The developed model achieves a coupled description of the majorphenomena: refining reactions, mass transfers between phases, scrapmelting, post-combustion, slag formation. The calculated exhaustfumes enthalpy is fitting well the measured thermal balance trials withindustrial converter when implementing a detailed description of thepost-combustion. This model, compatible with real-time use, is also avaluable tool for further improvement in dynamic control of the process.