Integrated LNG cold energy recovery through Organic Rankine Cycle, Kalina, Direct Expansion Cycle, and Brayton cycles for enhanced sustainable power generation and economic feasibility

Abstract This study explores a sustainable power generation approach by utilizing the untapped cold energy from liquefied natural gas (LNG) regasification. Despite LNG's role as a transitional fuel, its cryogenic potential remains largely underutilized. A novel integrated system is proposed, combining four thermodynamic cycles: organic Rankine cycle (ORC), Kalina cycle, direct expansion cycle (DEC), and Brayton cycle for maximum energy recovery. Thermodynamic and economic simulations were conducted using Aspen HYSYS (v12.1), incorporating steady‐state, adiabatic modeling, parametric optimization, and exergy analysis. Results show an increase in power output from a base of 50.74 to 64.12 MW through optimization, with a payback period of 5.87 years. The system's innovation lies in its cascade configuration, matching specific cycles to LNG's temperature zones, minimizing exergy loss. Unlike conventional methods, the synergy among cycles enhances overall efficiency. Customized working fluids and temperature‐optimized recovery further boost performance. Economic assessments confirm feasibility with balanced CAPEX and OPEX. The proposed system reduces greenhouse gas emissions, improves LNG terminal energy independence, and offers a scalable, low‐carbon solution. This research presents a transformative framework for LNG cold energy recovery, contributing to global decarbonization efforts and the advancement of sustainable energy infrastructure.