Cascade organic rankine cycle integrated with a cogeneration system for data center backup power: Design and thermodynamic analysis

Cogeneration, the simultaneous production of power and heat, is increasingly relevant for enhancing overall energy utilization and efficiency. This study investigates a cogeneration system integrated with a cascade Organic Rankine Cycle (CORC), designed to support backup power and thermal management for data centers. Organic fluids R227ea and R116 are employed in the top and bottom stages of the cascade cycle, respectively. The system’s electrical output, heat generation, and overall efficiency are evaluated. Results indicate that the cogeneration system and the cascade ORC produce approximately 31 MW and 4 MW of electrical power, respectively, while delivering a total heat load of 181 MW with a thermal efficiency near 87%. A sensitivity analysis identifies key parameters affecting output power, heat load, and efficiency, revealing that increasing the flow rate and temperature in each stream has the greatest impact on maximizing electricity generation, whereas higher inlet flows improve thermal efficiency. The novelty of this work lies in integrating a cascade ORC downstream of a conventional cogeneration system specifically for data center applications, allowing simultaneous electricity generation, heat recovery, and natural gas production, while providing operational flexibility that allows data centers to use excess power or shift workloads in response to demand.