Part-load performance analysis of an intercooled and recuperative gas turbine system integrated with transcritical organic Rankine cycle

Gas turbine propulsion systems are widely used in modern commercial ships due to their high power density, reliability, and operational flexibility. However, their efficiency often drops significantly under varying load conditions. To address this issue, a novel intercooled and recuperative gas turbine system integrated with transcritical organic Rankine cycle (ICR-GT-TORC) was proposed in the present work. The system performance was evaluated under both design and off-design conditions using thermodynamic and off-design models developed with Thermoflex software. Comparative analysis with conventional UGT25000 marine gas turbines revealed that the ICR-GT-TORC system achieved an efficiency of 49.4% and a power output of 38.1 MW, reflecting improvements of 29.3% and 37.6%, respectively. Moreover, the ICR-GT-TORC and ICR-GT system demonstrated significant advantages under part-load conditions. At 30% load, the efficiency of the ICR-GT-TORC system remained high at 43.7%, with a reduction of 11.5%. The ICR-GT system maintained an efficiency of 40.9%, with only a 7.9% reduction. In contrast, the efficiency of the simple cycle dropped significantly to 28.4%, with a 25.7% decrease. These findings could provide valuable insights into optimizing marine propulsion systems for off-design performance.