Design and Optimization of a Novel Kalina‐Organic Rankine Cycle System Based on LNG Cold Energy Utilization

ABSTRACT This study proposes a novel integrated system (SDKC‐DORC) that combines a split‐flow dual‐pressure Kalina cycle with a secondary organic Rankine cycle for the synergistic utilization of solar energy and liquefied natural gas (LNG) cold energy. The system performance is simulated in Aspen HYSYS, and a parametric analysis is conducted to evaluate the effects of four key variables: the evaporation temperature ( t 8 ), the mass flow rate of the second‐stage ORC ( q m,35 ), the split ratio ( x 5 ), and the inlet pressure of Turbine 4 ( P 50 ). The proposed integrated system, which harnesses solar energy and LNG through a novel combination of dual‐pressure Kalina and organic Rankine cycles, emerges as a pivotal strategy for low‐grade thermal energy utilization, demonstrating exceptional performance. Multiobjective optimization results indicate that the SDKC‐DORC configuration achieves optimal energy efficiency, electrical efficiency, and unit product cost of 65.82%, 60.26%, and 20.05$/GJ, respectively. A comparative analysis further reveals its superior thermodynamic and economic performance over the dual‐pressure Kalina two‐stage organic Rankine cycle (DKC‐DORC). Under identical operating conditions, the SDKC‐DORC system exhibits enhancements of 271.51 kW in net power output, 21.64% in energy efficiency, 10.63% in electrical efficiency, and 6.66% in cold recovery rate. Economically, it also presents a substantially higher annual net asset value, exceeding that of the DKC‐DORC system by $3.06 × 10 5 .