The type of fluid used in a system that recovers waste heat from a ship's engine is crucial for its performance. In this study, researchers analyzed different organic fluids to find the best one for the job. They considered factors like safety, efficiency, and work capacity. The results showed that as the engine works harder, the system produces more power but becomes less efficient. They found that R365mfc is the most suitable fluid for this system, offering a good balance of work capacity and efficiency.