Abstract
This paper reviews the second law analysis of thermodynamics in enclosures due to buoyancy-induced flow for energy systems. It defines entropy generation minimization or thermodynamic optimization. In addition, the article summarizes the recent works on entropy generation in buoyancy-induced flows in cavity and channels. Studies on mixed convection were also included in the study. Presentation was performed for flow in porous media and viscous fluid filled media at different shaped enclosures and duct under buoyancy-induced force.