Dynamic modeling and control of a solar-powered Brayton cycle using supercritical CO2 and optimization of its thermal energy storage

Delsoto, G.S.; Battisti, Felipe G.; Silva, A.K. da

doi:10.1016/j.renene.2023.01.088

Cited by 16 publications

(3 citation statements)

References 28 publications

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“…In recent years, S-CO 2 has gained increasing attention as a lubricant in high-speed rotating machinery due to its high viscosity index, low compressibility and high thermal conductivity (Yi et al, 2023). It provides higher work efficiency at a lower cost for compact and oil-free turbine machinery (Delsoto et al, 2023). Moreover, S-CO 2 is an environmentally friendly energy source, making it ideal for Brayton cycle power generation systems.…”

Section: Introductionmentioning

confidence: 99%

Structural stiffness and equivalent viscous damping in a supercritical carbon dioxide lubricated hybrid journal bearing under hydrostatic status

Zhu,

Qiu,

Chen

et al. 2023

ILT

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Purpose The purpose of this paper is to propose a type of hybrid bearing lubricated with supercritical carbon dioxide (S-CO2) and to investigate the stiffness and damping characteristics of the bearing under hydrostatic status. Design/methodology/approach Established a test rig for radial bearings lubricated with S-CO2 and used it to measure the dynamic coefficients by recording the relative and absolute displacements of bearing. Test bearing is mounted on a nonrotating, stiff shaft. Using static loading experiments to obtain structural stiffness. The dynamic coefficient regularities of the test bearing under hydrostatic status were revealed through dynamic loading experiments. Findings Experiment results indicate that test bearing displayed increased stiffness when subjected to high excitation frequencies and low excitation forces, as well as elevated damping when exposed to low excitation frequencies and low excitation forces. Additionally, an increase in either environmental pressure or hydrostatic recess pressure can elevate the dynamic coefficient. The effect of temperature on the dynamic coefficient is more pronounced around the critical temperature of S-CO2. Originality/value Designed a type of hybrid bearing for use in the Brayton cycle that is lubricated with S-CO2 and uses hydrostatic lubrication during start-stop and hydrodynamic lubrication during high-speed operation. The hybrid bearing reduces the wear and friction power consumption of gas bearing. However, few experimental analyses have been conducted by researchers in this field.

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Section: Introductionmentioning

confidence: 99%

Structural stiffness and equivalent viscous damping in a supercritical carbon dioxide lubricated hybrid journal bearing under hydrostatic status

Zhu,

Qiu,

Chen

et al. 2023

ILT

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“…Recently, ref. [23] analyzed the dynamic behavior of a solar-driven CSP plant with an RcBC modeled using Dyreby's methodology. The research aimed to optimize the TES system and solar field sizes to minimize the required auxiliary heating.…”

Section: Introductionmentioning

confidence: 99%

Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO2 Recompression Brayton Cycle

et al. 2023

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The latest generation of concentrated solar power (CSP) systems uses supercritical carbon dioxide (s-CO2) as the working fluid in a high-performance recompression Brayton cycle (RcBC), whose off-design performance under different environmental conditions has yet to be fully explored. This study presents a model developed using the Engineering Equation Solver (EES) and System Advisor Model (SAM) to evaluate the operation of two solar-driven s-CO2 RcBCs over a year, considering meteorological conditions in northern Chile. Under design conditions, the power plant outputs a net power of 25 MW with a first-law efficiency of 48.3%. An exergy analysis reveals that the high-temperature recuperator contributes the most to the exergy destruction under nominal conditions. However, the yearly simulation shows that the gas cooler’s exergy destruction increases at high ambient temperatures, as does the turbine’s during off-design operation. The proposed cycle widens the operational range, offering a higher flexibility and synergistic turndown strategy by throttling the mass flow. The proposed cycle’s seasonal first-law efficiency of 39% outweighs the literature cycle’s 29%. When coupled to a thermal energy storage system, the proposed cycle’s capacity factor could reach 93.45%, compared to the value 76.45% reported for the cycle configuration taken from the literature.

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“…Superior thermal efficiency, lower greenhouse gas emissions, compact design, cheap capital cost, and other advantages could be offered by sCO2-BCs in terms of energy, economy, and the environment [7]. SCO2-BCs can be easily integrated into many applications, such as solar energy [8], geothermal energy [9], nuclear energy [10], and waste heat [11].…”

Section: Introductionmentioning

confidence: 99%

Single-Flow Supercritical CO2 Brayton Cycles: A Performance Comparison of the Different Layouts

TOKER

Kızılkan

2023

ICAENS

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Supercritical CO2 Brayton cycle (sCO2-BC) has been frequently used in power generation applications in recent years due to its high efficiency, compact size, and low-cost advantages. In this study, performances of different configurations of single-flow sCO2-BCs, such as recuperation, intercooling, reheating, pre-compression, inter-recuperation, and split expansion, are examined. Firstly, thermodynamic analyzes of six different single-flow sCO2-BCs were conducted. Secondly, parametric analyses based on the system performance-influencing parameters, such as turbine input temperature, turbine inlet pressure, and compressor inlet pressure, were carried out. Engineering Equation Solver (EES) computer software was used in the analysis. According to the initially accepted design parameters, the highest energy efficiency was calculated as 39.25 % in the reheating cycle, and the lowest efficiency was found as 29.62 % in the split expansion BC. Moreover, it has been determined that the energy and exergy efficiencies of cycles increase with rising turbine input temperature and turbine input pressure.

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Dynamic modeling and control of a solar-powered Brayton cycle using supercritical CO2 and optimization of its thermal energy storage

Cited by 16 publications

References 28 publications

Structural stiffness and equivalent viscous damping in a supercritical carbon dioxide lubricated hybrid journal bearing under hydrostatic status

Structural stiffness and equivalent viscous damping in a supercritical carbon dioxide lubricated hybrid journal bearing under hydrostatic status

Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO2 Recompression Brayton Cycle

Single-Flow Supercritical CO2 Brayton Cycles: A Performance Comparison of the Different Layouts

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