The energy fluxes carried away from the waste recycling system are shown on the right hand side of equation (1). The use of a recovery boiler within the processing system allows the main energy flux carried away from the system to be the usable (effective) en- ergy flux (E_ ue). Other fluxes of energy carried away from the system are the total energy losses S(E_el), consisting of the losses of heat fluxes through the external walls of combustion chambers, after combustion chambers, concrete ducts and recovery boiler, as well as energy fluxes in the form of the physical and chemical enthalpy of ash.