Thermodynamic analysis and optimization of supercritical carbon dioxide Brayton cycles for use with low-grade geothermal heat sources

Ruiz-Casanova, Eduardo; Rubio-Maya, Carlos; Pacheco-Ibarra, J. Jesús; Ambriz-Díaz, Víctor M.; Romero, Carlos E.; Wang, Xingchao

doi:10.1016/j.enconman.2020.112978

Cited by 61 publications

(13 citation statements)

References 33 publications

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“…Few investigations have evaluated the feasibility of the sCO 2 cycle for the utilization of geothermal energy. Ruiz-Casanova et al (Ruiz-Casanova et al, 2020) compared four different configurations and reported that intercooling could reduce the mass flow of CO 2 and thus decline the compression work. Regeneration slightly increased the mass flow rate of CO 2 , resulting in an increase in the power output.…”

Section: Geothermal Power Generationmentioning

confidence: 99%

System Design and Application of Supercritical and Transcritical CO2 Power Cycles: A Review

2021

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Improving energy efficiency and reducing carbon emissions are crucial for the technological advancement of power systems. Various carbon dioxide (CO2) power cycles have been proposed for various applications. For high-temperature heat sources, the CO2 power system is more efficient than the ultra-supercritical steam Rankine cycle. As a working fluid, CO2 exhibits environmentally friendly properties. CO2 can be used as an alternative to organic working fluids in small- and medium-sized power systems for low-grade heat sources. In this paper, the main configurations and performance characteristics of CO2 power systems are reviewed. Furthermore, recent system improvements of CO2 power cycles, including supercritical Brayton cycles and transcritical Rankine cycles, are presented. Applications of combined systems and their economic performance are discussed. Finally, the challenges and potential future developments of CO2 power cycles are discussed. CO2 power cycles have their advantages in various applications. As working fluids must exhibit environmentally-friendly properties, CO2 power cycles provide an alternative for power generation, especially for low-grade heat sources.

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Section: Geothermal Power Generationmentioning

confidence: 99%

System Design and Application of Supercritical and Transcritical CO2 Power Cycles: A Review

2021

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“…8,9 So far, S-CO 2 cycle has been extended to solar energy, 10,11 fossil fuel, 12 fuel cell, 13 and geothermal energy. 14 In recent years, relevant researches have been intensively conducted, and various efficient cycle configurations including recuperated cycle, recompression cycle, and pre-compression cycle, have been constructed according to the characteristics of heat sources. Detailed review of these works can be found in References 15-17.…”

Section: Thermodynamic Cycles For Waste Heat Recoverymentioning

confidence: 99%

Development of a novel dual heated cascade supercritical carbon dioxide cycle and performance comparison with existing two configurations for waste heat recovery

Lin

Chen

Yin

et al. 2021

Intl J of Energy Research

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As an efficient method for the waste heat recovery of gas turbine, supercritical carbon dioxide (S-CO 2 ) power cycle has gained much attention, due to the high efficiency and compact structure. Thus, in this work, a novel S-CO 2 power cycle is developed for the waste heat recovery via the modification of dual heated cascade cycle with an intercooler (intercooling cycle). Compared with the dual heated cascade cycle (original cycle) and the intercooling cycle, the novel cycle has independent pressures at different heaters and turbines. To analyze the system performance, thermodynamic models are established and a genetic algorithm (GA) is applied to optimize the decision variables with the maximization of net work. These variables include two turbine inlet temperatures, a middle pressure, a low pressure, and a split ratio. Thereafter, thermodynamic parameters of the considered three cycles are obtained under different waste gas temperatures. For the recovery of 600 C waste gas, the novel cycle has the highest net work 3957.87 kW, while the lowest net work 3735.32 kW is obtained by the original cycle. For the effects of decision variables, a higher high-temperature turbine inlet temperature means a lower net work, while the increase of low-temperature turbine inlet temperature results in small increases of cycle performances. On the other hand, under the constraints of the pinch point, with the increase of low and middle pressures, the net work of the novel cycle increases. A higher net work is usually obtained at a lower split ratio. Furthermore, at different waste gas inlet temperatures, the highest cycle efficiency is always derived by the proposed cycle. For the net work, the proposed cycle has the highest value in the temperature range 600 C-750 C.

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“…The result of their study pointed out that 2.65% efficiency improvement could be achieved by using MCIC. Ruiz-Casanova et al [15] conducted the thermodynamic analysis of four different S-CO2 Brayton cycles for low-grade geothermal heat source application. Based on their study conditions, the intercooling recuperated Brayton cycle could achieve the highest electric power output, energy and exergy efficiencies.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic investigation of intercooling location effect on supercritical CO2 recompression Brayton cycle

Jarungthammachote

2021

JMES

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In S-CO2 recompression Brayton cycle, use of intercooling is a way to improve the cycle efficiency. However, it may decrease the efficiency due to increase of heat rejection. In this work, two S-CO2 recompression Brayton cycles are investigated using the thermodynamic model. The first cycle has intercoolings in a main compression and a recompression process (MCRCIC) and the second cycle has an intercooling in only the recompression process (RCIC). The thermal efficiencies of both cycles are compared with that of S-CO2 recompression Brayton cycle with intercooling in the main compression process (MCIC). Effects of a split fraction (SF) and a ratio of pressure ratio of the recompression (RPRRC) on the thermal efficiencies of MCRCIC and RCIC are also studied. The study results show that the intercooling of recompressor in MCRCIC and RCIC can reduce the compression power. However, it also rejects heat from the cycle and this leads to increasing added heat in the heater. The thermal efficiency of MCRCIC and RCIC are, then, lower than that of the MCIC. For the effects of RPRRC and SF to the thermal efficiency of the cycles, in general, when RPRRC increases, the thermal efficiency decreases due to increasing rejected heat. The increase in SF causes increasing thermal efficiency of the cycles and the thermal efficiency, then, decrease when SF is beyond the optimal value.

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Thermodynamic analysis and optimization of supercritical carbon dioxide Brayton cycles for use with low-grade geothermal heat sources

Cited by 61 publications

References 33 publications

System Design and Application of Supercritical and Transcritical CO2 Power Cycles: A Review

System Design and Application of Supercritical and Transcritical CO2 Power Cycles: A Review

Development of a novel dual heated cascade supercritical carbon dioxide cycle and performance comparison with existing two configurations for waste heat recovery

Thermodynamic investigation of intercooling location effect on supercritical CO2 recompression Brayton cycle

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