This paper starts with a short analysis of the performance of currently applied glass melting processes/furnaces concerning their energy consumption levels (benchmarking), as well as NOx emissions. The best practice situations will be presented for a few glass products (e.g. container glass). Potential improvements in furnace designs to obtain more intensified melting or smaller glass furnace sizes and improved-controlled process steps (melting-in, complete raw material, digestion of the melt, fining, homogenisation and conditioning) will be discussed. Important aspects per process step and control of the applied temperature level, finding optimum glass melt flow regimes and residence times in each compartment of the melting tank, dedicated for a specific process step. Controlled and intensified heat transfer to the batch blanket area is decisive for the possibility to reduce glass furnace size, and consequently lowering structural energy losses. Mathematical modeling studies support the development of new furnace designs and heating methods in industrial glass furnaces with targeted high energy efficiency and moderate/low NOx emissions. New technological elements, such as application of CFD models, innovative oxygen-firing glass furnace designs, improved refractory materials, and advanced process control systems support the development of new glass melting concepts and furnace designs.
