Thermoeconomic Analysis and Optimization of a New Combined Supercritical Carbon Dioxide Recompression Brayton/Kalina Cycle

Abstract

Abstract:A new combined supercritical CO 2 recompression Brayton/Kalina cycle (SCRB/KC) is proposed. In the proposed system, waste heat from a supercritical CO 2 recompression Brayton cycle (SCRBC) is recovered by a Kalina cycle (KC) to generate additional electrical power. The performances of the two cycles are simulated and compared using mass, energy and exergy balances of the overall systems and their components. Using the SPECO (Specific Exergy Costing) approach and employing selected cost balance equations for the components of each system, the total product unit costs of the cycles are obtained. Parametric studies are performed to investigate the effects on the SCRB/KC and SCRBC thermodynamic and thermoeconomic performances of key decision parameters. In addition, considering the exergy efficiency and total product unit cost as criteria, optimization is performed for the SCRBC and SCRB/KC using Engineering Equation Solver software. The results indicate that the maximum exergy efficiency of the SCRB/KC is higher than that of the SCRBC by up to 10%, and that the minimum total product unit cost of the SCRB/KC is lower than that of the SCRBC by up to 4.9%.

Parametric optimisation of a combined supercritical CO2 (S-CO2) cycle and organic Rankine cycle (ORC) system for internal combustion engine (ICE) waste-heat recovery

“…Research on such combined-cycle systems is still limited, such as those employing Kalina cycle [24,25], CO2-based cycle [26,27] and organic Rankine cycle (ORC) [23] as alternatives for the bottoming cycle. ORC offers an attractive option to be adopted in S-CO2 cycle system as it has already been proven to be an effective heat-to-power technology [28][29][30][31], especially for heat sources at temperature ranges from 100 °C to 500 °C [32].…”

Thermodynamic and Exergoeconomic Analysis of a Supercritical CO2 Cycle Integrated with a LiBr-H2O Absorption Heat Pump for Combined Heat and Power Generation

“…Li et al [14] proposed a combined recompression sCO 2 /Kalina cycle, and found out that the total product unit cost and exergy efficiency of the combined cycle were 5.5% lower and 8.02% higher than those of the sCO 2 cycle. Mahmoudi et al [15] studied the thermodynamic and economic performances for a stand-alone sCO 2 cycle and a combined sCO 2 /Kalina cycle. Results showed that combining the Kalina cycle with the sCO 2 cycle could reduce the exergy destruction significantly.…”

Research and Development of Ship Waste Heat Driven S-CO2 Power Generation Coupled T-CO2 Refrigeration System

“…Zhang C et al [8] proposed that the lower cycle should be the ORC and the upper cycle should be the composite cycle of three different power cycles, aiming at the exhaust residual heat of internal combustion engines, and concluded that the traditional steam Rankine cycle and ORC composite cycle had the highest thermal efficiency, which was illustrated from another aspect the compound circulation system using carbon dioxide as working medium had higher efficiency. Akbari A D et al [9] studied the composite cycle of recompressing S-CO2 and ORC, and the results showed that the thermal efficiency of re-compressing S-CO 2 /ORC was 11.7% higher than that of re-compressing S-CO 2 . In the dynamic recovery of flue gas waste heat, due to the approximate change of specific heat of CO 2 and flue gas, the heat exchange process would achieve a good match.…”