scholarly journals Comparing line-focusing and central tower solar power plants with s-CO2 binary mixture Brayton power cycles

2020 ◽  
Author(s):  
Robert Valencia-Chapi ◽  
Luis Coco-Enríquez ◽  
Javier Muñoz-Antón
Keyword(s):  
Binary Mixture ◽  
Power Plants ◽  
Solar Power ◽  
Power Cycles ◽  
Solar Power Plants

S-Ethane Brayton Power Conversion Systems for Concentrated Solar Power Plant

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Luis Coco Enríquez ◽  
Javier Muñoz-Antón ◽  
José María Martínez-Val Peñalosa
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Subcritical Water ◽  
Plant Performance ◽  
Solar Collectors ◽  
Steam Generation ◽  
Concentrated Solar Power ◽  
Power Cycles ◽  
Solar Power Plants ◽  
Recompression Cycle

The objective of this investigation is the comparison between supercritical ethane (s-ethane, C2H6) and supercritical carbon dioxide (s-CO2) Brayton power cycles for line-focusing concentrated solar power plants (CSP). In this study, CSP are analyzed with linear solar collectors (parabolic trough (PTC) or linear Fresnel (LF)), direct molten salt (MS), or direct steam generation (DSG) as heat transfer fluids (HTF), and four supercritical Brayton power cycles configurations: simple Brayton cycle (SB), recompression cycle (RC), partial cooling with recompression cycle (PCRC), and recompression with main compression intercooling cycle (RCMCI). All Brayton power cycles were assessed with two working fluids: s-CO2 and s-ethane. As a main result, we confirmed that s-ethane Brayton power cycles provide better net plant performance than s-CO2 cycles for turbine inlet temperatures (TITs) from 300 °C to 550 °C. As an example, the s-ethane RCMCI plant configuration net efficiency is ∼42.11% for TIT = 400 °C, and with s-CO2 the plant performance is ∼40%. The CSP Brayton power plants were also compared with another state-of-the-art CSP with DSG in linear solar collectors and a subcritical water Rankine power cycle with direct reheating (DRH), and a maximum plant performance between ∼40% and 41% (TIT = 550 °C).

scholarly journals Dual Loop line-focusing solar power plants with supercritical Brayton power cycles

2017 ◽  
Vol 42 (28) ◽  
pp. 17664-17680 ◽  
Author(s):  
L. Coco-Enríquez ◽  
J. Muñoz-Antón ◽  
J.M. Martínez-Val
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Power Cycles ◽  
Solar Power Plants

Thermo-Economic Analyses and Comparisons of Two S-CO2-Brayton-Cycle-Based Combined Power Cycles for Concentrated Solar Power Plants

2018 ◽  
Author(s):  
Yuegeng Ma ◽  
Xuwei Zhang ◽  
Ming Liu ◽  
Jiping Liu
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Concentrated Solar Power ◽  
Power Cycles ◽  
Solar Power Plants ◽  
Cycle Efficiency ◽  
Concentrated Solar Power Plants ◽  
Residual Heat

In order to pursue superior cycle efficiency and lower power generation cost for the CSP plants, two S-CO2–Brayton–cycle–based power cycles with different utilization methods of the residual heat recover of the top S-CO2 Brayton cycle (SCBC) are investigated to seek alternatives to the stand-alone S-CO2 cycle as the power block of concentrated solar power plants. The residual heat released by the top S-CO2 cycle are either utilized to drive a LiBr absorption chiller (AC) for further chilling of the CO2 fluids exiting the precooler before entering the main compressor inlet temperature or recovered by an organic rankine cycle (ORC) for generating electricity. Thermo-economic analysis and optimization are performed for the SCBC–AC and SCBC–ORC, respectively. The results show that the thermal and exergetic efficiencies of the SCBC–AC are comparable with those of the SCBC–ORC in low pressure ratio conditions (PR<2.7) but are apparently lower than SCBC–ORC when PR is over 2.7. The LCOE of the CSP plant integrated with SCBC–AC is more sensitive to the change of PR. The optimal PR to maximum the cycle efficiency or minimize the plant LCOE for the SCBC–ORC is higher than that for the SCBC–AC, while the optimal recuperator effectiveness to minimize the LCOE of CSP plant integrated with SCBC–ORC is lower than that of SCBC–AC. The optimization results show that the thermo-economic performance of the SCBC–AC is comparable to that of the SCBC–ORC. Significant ηex improvement and LCOE reduction can be obtained by both the two combined cycles relative to the stand-alone S-CO2 cycle. The maximal ηex improvements obtained by the SCBC–ORC and SCBC–AC are 6.83% and 4.12%, respectively. The maximal LCOE reduction obtained by the SCBC-ORC and SCBC–AC are 0.70 ȼ / (kW·h) and 0.60 ȼ / (kW·h), respectively.

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

2019 ◽  
Vol 10 (1) ◽  
pp. 55 ◽  
Author(s):  
Robert Valencia-Chapi ◽  
Luis Coco-Enríquez ◽  
Javier Muñoz-Antón
Keyword(s):  
Supercritical Co2 ◽  
Power Plants ◽  
Solar Power ◽  
Plant Performance ◽  
Design Parameters ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Power Cycles ◽  
Solar Power Plants ◽  
Dry Cooling

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.

scholarly journals Capital Cost Assessment of Concentrated Solar Power Plants Based on Supercritical Carbon Dioxide Power Cycles

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Francesco Crespi ◽  
David Sánchez ◽  
Tomás Sánchez ◽  
Gonzalo S. Martínez
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Cost Effective ◽  
Capital Cost ◽  
Operating Conditions ◽  
Concentrated Solar Power ◽  
Power Cycles ◽  
Solar Power Plants ◽  
Major Equipment ◽  
Solar Field

Previous work by the authors has shown that broader analyses than those typically found in literature (in terms of operating pressures allowed) can yield interesting conclusions with respect to the best candidate cycles for certain applications. This has been tested for the thermodynamic performance (first and second laws) but it can also be applied from an economic standpoint. This second approach is introduced in this work where typical operating conditions for concentrated solar power (CSP) applications (current and future generations of solar tower plants) are considered (750 °C and 30 MPa). For these, the techno-economic performance of each cycle is assessed in order to identify the most cost-effective layout when it comes to the overnight capital cost (OCC). This analysis accounts for the different contributions to the total cost of the plant, including all the major equipment that is usually found in a CSP power plant such as the solar field and thermal energy storage (TES) system. The work is, thus, aimed at providing guidelines to professionals in the area of basic engineering and prefeasibility study of CSP plants who find themselves in the process of selecting a particular power cycle for a new project (set of specifications and boundary conditions).

scholarly journals Potential of Supercritical Carbon Dioxide Power Cycles to Reduce the Levelised Cost of Electricity of Contemporary Concentrated Solar Power Plants

2020 ◽  
Vol 10 (15) ◽  
pp. 5049 ◽  
Author(s):  
Francesco Crespi ◽  
David Sánchez ◽  
Gonzalo S. Martínez ◽  
Tomás Sánchez-Lencero ◽  
Francisco Jiménez-Espadafor
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Power Plants ◽  
Solar Power ◽  
Concentrated Solar Power ◽  
Power Cycles ◽  
Cost Of Electricity ◽  
Solar Power Plants ◽  
Concentrated Solar Power Plants ◽  
Supercritical Carbon

This paper provides an assessment of the expected Levelised Cost of Electricity enabled by Concentrated Solar Power plants based on Supercritical Carbon Dioxide (sCO 2 ) technology. A global approach is presented, relying on previous results by the authors in order to ascertain whether these innovative power cycles have the potential to achieve the very low costs of electricity reported in the literature. From a previous thermodynamic analysis of sCO 2 cycles, three layouts are shortlisted and their installation costs are compared prior to assessing the corresponding cost of electricity. Amongst them, the Transcritical layout is then discarded due to the virtually impossible implementation in locations with high ambient temperature. The remaining layouts, Allam and Partial Cooling are then modelled and their Levelised Cost of Electricity is calculated for a number of cases and two different locations in North America. Each case is characterised by a different dispatch control scheme and set of financial assumptions. A Concentrated Solar Power plant based on steam turbine technology is also added to the assessment for the sake of comparison. The analysis yields electricity costs varying in the range from 8 to over 11 ¢/kWh, which is near but definitely not below the 6 ¢/kWh target set forth by different administrations. Nevertheless, in spite of the results, a review of the conservative assumptions adopted in the analysis suggests that attaining costs substantially lower than this is very likely. In other words, the results presented in this paper can be taken as an upper limit of the economic performance attainable by Supercritical Carbon Dioxide in Concentrated Solar Power applications.

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