On the Conceptual Design of Novel Supercritical CO2 Power Cycles for Waste Heat Recovery

Manente, Giovanni; Costa, Mário

doi:10.3390/en13020370

Cited by 37 publications

(14 citation statements)

References 33 publications

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“…Validation of conditions at boundaries was carried by comparing the code boundary data with the experimental results of Ishizuka et al [33]. On the other hand, the validation of the nodal data was conducted by comparing the temperature profiles obtained from the code with the temperature profiles extracted from the previous study's CFD results [3]. Numerical results employed for the validation were taken from the CFD model [3] that was authenticated using experimental data [33].…”

Section: Correlations Channel Geometrymentioning

confidence: 99%

“…On the other hand, the validation of the nodal data was conducted by comparing the temperature profiles obtained from the code with the temperature profiles extracted from the previous study's CFD results [3]. Numerical results employed for the validation were taken from the CFD model [3] that was authenticated using experimental data [33]. The validation purpose's boundary conditions are listed in Table 2, while a comparison of the PCHE-DAC data with the experimental data Kim et al [34] = 0.0292 0.8742 , = 0.2515 −0.2031 ; (θ = 32 0 ) = 0.0188 0.8742 , = 0.2881 −0.1322 ; (θ = 40 0 ) (2,000 ≤ ≤ 58,000) (0.7 ≤ ≤ 1.0)…”

Section: Correlations Channel Geometrymentioning

confidence: 99%

“…Furthermore, it can gain high thermal efficiency due to its capability to operate at very high turbine inlet temperatures. Apart from its ability to achieve higher thermal efficiency, the cycle layout of the sCO 2 − BC is compact and straightforward [1,2] (at least ten times more compact in Comparison with the Rankine Cycle) due to its operation at very high pressure .This makes it an ideal cycle for power generation [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…Comparison of the temperature profiles computed using PCHE-DAC with the extracted temperature data from the computational fluid dynamics (CFD) analysis[3].…”

mentioning

confidence: 99%

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Performance of Supercritical CO2 Power Cycle and Its Turbomachinery with the Printed Circuit Heat Exchanger with Straight and Zigzag Channels

2020

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Since printed circuit heat exchangers (PCHE) are the largest modules of a supercritical carbon dioxide Brayton cycle, they can considerably affect the whole system’s performance and layout. Straight-channel and zigzag-channel printed circuit heat exchangers have frequently been analyzed in the standalone mode and repeatedly proposed for sCO2−BC. However, the impact of heat exchanger designs with straight and zigzag-channel configurations on the performance of the cycle and its components, i.e., the turbine and compressor, has not been studied. In this context, this study evaluates the effect of different heat exchanger designs with various values of effectiveness (ϵ), inlet Reynolds number (Re), and channel configuration (zigzag and straight channel) on the overall performance of the sCO2−BC and its components. For the design and analysis of PCHEs, an in-house PCHE design and analysis code (PCHE-DAC) was developed in the MATLAB environment. The sCO2−BC performance was evaluated utilizing an in-house cycle simulation and analysis code (CSAC) that employs the heat exchanger design code as a subroutine. The results suggest that pressure drop in PCHEs with straight-channel configuration is up to 3.0 times larger than in PCHEs with zigzag-channel configuration. It was found that a higher pressure drop in the PCHEs with straight channels can be attributed to substantially longer channel lengths required for these designs (up to 4.1 times than zigzag-channels) based on the poor heat transfer characteristics associated with these channel geometries. Thus, cycle layouts using PCHEs with a straight-channel configuration impart a much higher load (up to 1.13 times) on the recompression compressor, this in turn, results in a lower pressure ratio across the turbine. Therefore, the overall performance of the sCO2−BC using PCHEs with straight-channel configurations is found to be substantially inferior to that of layouts using PCHEs with zigzag-channel configurations. Finally, optimization results suggest that heat exchanger’s design with inlet Reynolds number and heat exchanger effectiveness ranging from 32 k to 42 k and 0.94>ϵ>0.87, respectively, are optimal for sCO2−BC and present a good bargain between cycle efficiency and its layout size.

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Section: Correlations Channel Geometrymentioning

confidence: 99%

Section: Correlations Channel Geometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Comparison of the temperature profiles computed using PCHE-DAC with the extracted temperature data from the computational fluid dynamics (CFD) analysis[3].…”

mentioning

confidence: 99%

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Performance of Supercritical CO2 Power Cycle and Its Turbomachinery with the Printed Circuit Heat Exchanger with Straight and Zigzag Channels

2020

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“…Furthermore, due to the fact that the inert gas S-CO 2 is compatible with structural materials, the S-CO 2 cycle has the potential to achieve a higher turbine inlet temperature [2]. Today, the S-CO 2 cycle has been widely applied in various energy sources, such as nuclear energy, solar energy, geothermal energy, and waste heat utilization [3][4][5][6][7]. Much effort has been paid to conduct the theoretical modeling on the thermodynamic processes and the performance comparison of different cycle layouts based on the property characteristics of S-CO 2 [8,9].…”

Section: Introductionmentioning

confidence: 99%

New Knowledge on the Performance of Supercritical Brayton Cycle with CO2-Based Mixtures

Zhao

et al. 2020

Energies

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As one of the promising technologies to meet the increasing demand for electricity, supercritical CO2 (S-CO2) Brayton cycle has the characteristics of high efficiency, economic structure, and compact turbomachinery. These characteristics are closely related to the thermodynamic properties of working fluid. When CO2 is mixed with other gas, cycle parameters are determined by the constituent and the mass fraction of CO2. Therefore, in this contribution, a thermodynamic model is developed and validated for the recompression cycle. Seven types of CO2-based mixtures, namely CO2-Xe, CO2-Kr, CO2-O2, CO2-Ar, CO2-N2, CO2-Ne, and CO2-He, are employed. At different CO2 mass fractions, cycle parameters are determined under a fixed compressor inlet temperature, based on the maximization of cycle efficiency. Cycle performance and recuperators’ parameters are comprehensively compared for different CO2-based mixtures. Furthermore, in order to investigate the effect of compressor inlet temperature, cycle parameters of CO2-N2 are obtained under four different temperatures. From the obtained results, it can be concluded that, as the mass fraction of CO2 increases, different mixtures show different variations of cycle performance and recuperators’ parameters. In generally, the performance order of mixtures coincides with the descending or ascending order of corresponding critical temperatures. Performance curves of these considered mixtures locate between the curves of CO2-Xe and CO2-He. Meanwhile, the curves of CO2-O2 and CO2-N2 are always closed to each other at high CO2 mass fractions. In addition, with the increase of compressor inlet temperature, cycle performance decreases, and more heat transfer occurs in the recuperators.

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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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On the Conceptual Design of Novel Supercritical CO2 Power Cycles for Waste Heat Recovery

Cited by 37 publications

References 33 publications

Performance of Supercritical CO2 Power Cycle and Its Turbomachinery with the Printed Circuit Heat Exchanger with Straight and Zigzag Channels

Performance of Supercritical CO2 Power Cycle and Its Turbomachinery with the Printed Circuit Heat Exchanger with Straight and Zigzag Channels

New Knowledge on the Performance of Supercritical Brayton Cycle with CO2-Based Mixtures

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

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