This paper has discussed energetic, exergetic, environmental and sustainability aspects of drying systems and included an
efficiency analysis through energy and exergy for performance assessment. An illustrative example has been presented to illustrate how energy and exergy efficiencies of the drying systems change with various process and operating parameters, e.g., drying air temperature, drying air flow rate, product weights, and relative humidity of drying air. The example presented here demonstrates the relations between energy, exergy and the environment and highlight the importance of utilizing exergy. Exergy appears to be as one of the most powerful tools in addressing and solving environmental problems and providing an effective method using the conservation of mass and conservation of energy principles together with the second law of thermodynamics for design, analysis and performance improvement of drying systems for better sustainability.