The Organic Rankine Cycle Energy Recovery System: An Overview systematically discusses heat recovery systems using fluid Organic Rankine cycles (ORCs). It considers the state of the art of the various systems, covering the configurations and production. Particular focus is given to working fluids, through a detailed analysis of key operational characteristics, and an analysis of existing configurations in the rapid prototyping phase is also included. Thermodynamic feasibility by means of numerous simulation is considered and finally developments, improvements and innovations are covered.