The advancing digitalisation in industry also opens up fascinating opportunities for more efficient operation and faster development of furnace systems and high-temperature processes for thermoprocess technology. The simulation methods available today make it possible to use furnace simulations of varying detail, from simple thermal balances to complex coupled models of entire industrial furnaces, for reliable forecasts of operating conditions and the expected result of heat treatment. The furnace models can be further developed into digital twins which, depending on their characteristics, can be used either for automated furnace control or targeted furnace and thermal process development. Fraunhofer-Center HTL is working with these methods in current projects and is continuously developing them further.