Thermodynamic mapping of power cycles working around the critical point

González-Portillo, Luis F.; Muñoz-Antón, Javier; Martínez-Val, José M.

doi:10.1016/j.enconman.2019.04.022

Cited by 12 publications

(14 citation statements)

References 30 publications

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“…These terms depend on the thermodynamic properties of the working fluid in the recompression cycle. Further, ∆h rg is the difference between the heat needed in a cycle working at real gas conditions and the heat needed in an ideal cycle [39]. It can be expressed by:…”

Section: Results Of 'Group A' Mixtures (Substances For Reducing the Cmentioning

confidence: 99%

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

2019

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This work quantifies the impact of using sCO2-mixtures (s-CO2/He, s-CO2/Kr, s-CO2/H2S, s-CO2/CH4, s-CO2/C2H6, s-CO2/C3H8, s-CO2/C4H8, s-CO2/C4H10, s-CO2/C5H10, s-CO2/C5H12 and s-CO2/C6H6) as the working fluid in the supercritical CO2 recompression Brayton cycle coupled with line-focusing solar power plants (with parabolic trough collectors (PTC) or linear Fresnel (LF)). Design parameters assessed are the solar plant performance at the design point, heat exchange dimensions, solar field aperture area, and cost variations in relation with admixtures mole fraction. The adopted methodology for the plant performance calculation is setting a constant heat recuperator total conductance (UAtotal). The main conclusion of this work is that the power cycle thermodynamic efficiency improves by about 3–4%, on a scale comparable to increasing the turbine inlet temperature when the cycle utilizes the mentioned sCO2-mixtures as the working fluid. On one hand, the substances He, Kr, CH4, and C2H6 reduce the critical temperature to approximately 273.15 K; in this scenario, the thermal efficiency is improved from 49% to 53% with pure s-CO2. This solution is very suitable for concentrated solar power plants coupled to s-CO2 Brayton power cycles (CSP-sCO2) with night sky cooling. On the other hand, when adopting an air-cooled heat exchanger (dry-cooling) as the ultimate heat sink, the critical temperatures studied at compressor inlet are from 318.15 K to 333.15 K, for this scenario other substances (C3H8, C4H8, C4H10, C5H10, C5H12 and C6H6) were analyzed. Thermodynamic results confirmed that the Brayton cycle efficiency also increased by about 3–4%. Since the ambient temperature variation plays an important role in solar power plants with dry-cooling systems, a CIT sensitivity analysis was also conducted, which constitutes the first approach to defining the optimum working fluid mixture for a given operating condition.

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Section: Results Of 'Group A' Mixtures (Substances For Reducing the Cmentioning

confidence: 99%

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

2019

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“…The fluid for the ORC was R123. Due to the increased interest in supercritical power cycles [ 13 ], Mohammadi, K. and McGowan [ 14 ] studied a similar system but installed a supercritical CO 2 (sCO 2 ) cycle as the bottoming cycle, where the gas turbine also included reheating, in addition to intercooling and recuperation. The authors compared toluene and isobutene for the ORC and concluded that isobutene had a better performance.…”

Section: Introductionmentioning

confidence: 99%

Analysis of an Integrated Solar Combined Cycle with Recuperative Gas Turbine and Double Recuperative and Double Expansion Propane Cycle

Rovira

Abbas

Muñoz

et al. 2020

Entropy

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The main objective of this paper is to present and analyze an innovative configuration of integrated solar combined cycle (ISCC). As novelties, the plant includes a recuperative gas turbine and the conventional bottoming Rankine cycle is replaced by a recently developed double recuperative double expansion (DRDE) cycle. The configuration results in a fuel saving in the combustion chamber at the expense of a decreased exhaust gas temperature, which is just adequate to feed the DRDE cycle that uses propane as the working fluid. The solar contribution comes from a solar field of parabolic trough collectors, with oil as the heat transfer fluid. The optimum integration point for the solar contribution is addressed. The performance of the proposed ISCC-R-DRDE design conditions and off-design operation was assessed (daily and yearly) at two different locations. All results were compared to those obtained under the same conditions by a conventional ISCC, as well as similar configurations without solar integration. The proposed configuration obtains a lower heat rate on a yearly basis in the studied locations and lower levelized cost of energy (LCOE) than that of the ISCC, which indicates that such a configuration could become a promising technology.

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“…The thermophysical properties of CO2 allow s-CO2 cycles to set the compressor inlet close to the critical point, which results in high cycle efficiency (González-Portillo et al, 2019;Rovira et al, 2014). Moreover, the CO2 have other advantages such as its availability, low cost and very good thermal stability at high temperature (Dostal, 2004).…”

Section: Introductionmentioning

confidence: 99%

Supercritical carbon dioxide cycles with multi-heating in Concentrating Solar Power plants

2020

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Thermodynamic mapping of power cycles working around the critical point

Cited by 12 publications

References 30 publications

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

Analysis of an Integrated Solar Combined Cycle with Recuperative Gas Turbine and Double Recuperative and Double Expansion Propane Cycle

Supercritical carbon dioxide cycles with multi-heating in Concentrating Solar Power plants

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