Understanding the thermodynamic inefficiencies in combustion processes

The thermodynamic inefficiencies associated with any energy conversion process are expressed by the exergy destruction and the exergy losses associated with the process. Combustion processes exhibit very high thermodynamic inefficiencies caused by chemical reaction, heat transfer, friction, and mixing. In this paper, we discuss how to estimate the thermodynamic inefficiencies resulting from each one of these sources. The thermodynamic evaluation can be conducted with the aid of either a conventional exergetic analysis or an advanced one. The latter allows estimation of the potential for improvement of the process being considered and demonstrates the interactions among the components of the system in which combustion takes place. The paper discusses how advanced exergy-based evaluations can be used to reduce the thermodynamic inefficiencies, costs, and environmental impacts associated with energy conversion systems including combustion processes.