Summary A multigeneration system comprising solid oxide fuel cell, compressed air energy storage, gas turbine, supercritical CO2 recompression Brayton cycle (S‐CO2), and organic flash Rankine cycle (OFRC) based on liquefied natural gas cold energy is proposed. The system integrates peak shaving, heating, cooling, power generation, and energy storage, solving the imbalance between the supply and demand of renewable energy. It is comprehensively analyzed from the thermodynamic, economic, and exergoeconomic perspectives to evaluate the performance of the three phases (full time, charging period, and discharging period). The evaluation shows that the exergy analysis of the multigeneration system alone is not comprehensive, and the exergoeconomic analysis is more necessary. Additionally, the S‐CO2 coupled with the OFRC generates power in a more efficient way than the S‐CO2 coupled with the Organic Rankine cycle (ORC) or Organic Flash cycle (OFC) does. Finally, the NSGA‐II and multi‐objective whale algorithms are employed to optimize the system. The results show that the multi‐objective whale algorithm is slightly better than the NSGA‐II. Moreover, the optimized round‐trip efficiency (RTE) and levelized cost of electricity (LCOE) are 68.64% and 0.053 $ kWh−1, respectively. Compared with the base design point, the RTE improves by 1.93%, and the LCOE decreases by 3.64%.

Energy conservation and emission reduction are inevitable strategies for alleviating energy shortages and environmental pollution, which can be achieved by improving the energy utilization efficiency and using cleaner energy. Waste heat recovery (WHR) is an effective strategy to improve the energy utilization efficiency of a system. [1] A common WHR approach involves the addition of a bottoming cycle, [2] such as the Rankine (RC), flash, Kalina (KC), Stirling, and Brayton cycles, with each bottoming cycle exhibiting a different WHR potential for various temperature ranges. In this regard, waste heat is typically categorized into low-(<230 °C), medium-(230-650 °C), and high-temperature residual heat (>650 °C). [3] Varma et al. [4] performed a comparative study of the performance of the organic Rankine cycle (ORC), organic flash cycle (OFC), and KC for recovering low-grade waste heat and found that the OFC, ORC, and KC with a specific temperature and solution concentration exhibited the highest power generation, efficiency, and power output among the investigated cycles, respectively. Zhang et al. [5] compared the steam Rankine cycle (SRC), ORC, and steam-organic Rankine cycle (S-ORC) and concluded that the ORC exhibited optimal thermodynamic performance at residual heat temperatures of 150-210 °C, whereas the S-ORC demonstrated superior performance at 210-350 °C. Liu et al. [6] compared the thermodynamic performance of the supercritical CO 2 Brayton cycle (S-CO 2 ) and SRC at high temperatures and found that the performance of S-CO 2 was superior to that of the SRC. Moreover, the performance parameters of the equipment were analyzed from the perspective of energy conservation. The aforementioned scholars compared the performance of the ORC, OFC, KC, SRC, S-ORC, and S-CO 2 cycles for recovering waste heat of different grades. These studies highlight the suitability of the S-CO 2 and ORC for high-temperature and low-grade WHR, respectively.China has prioritized the achievement of carbon peak and carbon neutrality to mitigate the severe problem of climate change as an environmental protection strategy and as an important basis for national economic competitiveness in the future. Therefore, the use of CO 2 as a working fluid must be reassessed. CO 2 has recently been shown to exhibit tremendous potential as