Optimum design point exploration and performance analysis of a novel CO₂ power generation system for LNG cold energy recovery: Considering the temperature fluctuation of heat source

Recovery of the cold energy released from the regasification process of Liquified natural gas (LNG) help to achieve the ‘carbon peaking and carbon neutrality’ goals. A novel CO₂ power generation system is proposed to utilize the LNG cold energy, and solar energy is introduced. Double loop configuration is designed with consideration of sunshine fluctuation, and the operation strategy is proposed for four working conditions. The off-design analysis is conducted to explore the system performance under various design point when the temperature of heat source changes. Through Discretizing the fluctuate solar radiation and weighted summing the net power output, the overall performance of the system under various conditions could be evaluated. Based on that, a composited optimization is conducted to determine the optimum design point that guarantee the overall system performance best under the temperature fluctuation of heat source. Results show that it could perform better with a lower design inlet temperature of the high-pressure turbine when the actual inlet temperature of heat source is relatively small but higher than 90 °C. The optimal design inlet temperature of high-pressure turbine is 170 °C, and the maximum net power output of the system over 24 h is 26253.44 MW∙h.