Thermodynamic Study of Advanced Supercritical Carbon Dioxide Power Cycles for Concentrating Solar Power Systems

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Craig S. Turchi ◽  
Zhiwen Ma ◽  
Ty W. Neises ◽  
Michael J. Wagner
Keyword(s):  
Power Systems ◽  
Solar Power ◽  
Department Of Energy ◽  
Thermal Mass ◽  
Brayton Cycle ◽  
Concentrating Solar Power ◽  
Power Cycles ◽  
Compact Size ◽  
Cycle Systems ◽  
Dry Cooling

Supercritical CO2 (s-CO2) operated in a closed-loop Brayton cycle offers the potential of higher cycle efficiency versus superheated or supercritical steam cycles at temperatures relevant for concentrating solar power (CSP) applications. Brayton-cycle systems using s-CO2 have a smaller weight and volume, lower thermal mass, and less complex power blocks versus Rankine cycles due to the higher density of the fluid and simpler cycle design. The simpler machinery and compact size of the s-CO2 process may also reduce the installation, maintenance, and operation cost of the system. In this work we explore s-CO2 Brayton cycle configurations that have attributes that are desirable from the perspective of a CSP application, such as the ability to accommodate dry cooling and achieve greater than 50% efficiency, as specified for the U.S. Department of Energy SunShot goal. Recompression cycles combined with intercooling and/or turbine reheat appear able to hit this efficiency target, even when combined with dry cooling. In addition, the intercooled cycles expand the temperature differential across the primary heat exchanger, which is favorable for CSP systems featuring sensible-heat thermal energy storage.

Thermodynamic Study of Advanced Supercritical Carbon Dioxide Power Cycles for High Performance Concentrating Solar Power Systems

2012 ◽  
Author(s):  
Craig S. Turchi ◽  
Zhiwen Ma ◽  
Ty Neises ◽  
Michael Wagner
Keyword(s):  
Power Systems ◽  
High Performance ◽  
High Efficiency ◽  
Solar Power ◽  
Thermal Power ◽  
Department Of Energy ◽  
Thermal Mass ◽  
Brayton Cycle ◽  
Concentrating Solar Power ◽  
Compact Size

In 2011, the U.S. Department of Energy (DOE) initiated a “SunShot Concentrating Solar Power R&D” program to develop technologies that have the potential for much higher efficiency, lower cost, and/or more reliable performance than existing CSP systems. The DOE seeks to develop highly disruptive Concentrating Solar Power (CSP) technologies that will meet 6¢/kWh cost targets by the end of the decade, and a high-efficiency, low-cost thermal power cycle is one of the important components to achieve the goal. Supercritical CO2 (s-CO2) operated in a closed-loop Brayton cycle offers the potential of equivalent or higher cycle efficiency versus superheated or supercritical steam cycles at temperatures relevant for CSP applications. Brayton-cycle systems using s-CO2 have a smaller weight and volume, lower thermal mass, and less complex power blocks versus Rankine cycles due to the higher density of the fluid and simpler cycle design. The simpler machinery and compact size of the s-CO2 process may also reduce the installation, maintenance and operation cost of the system.

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.

Heat transfer fluids for concentrating solar power systems – A review

2015 ◽  
Vol 146 ◽  
pp. 383-396 ◽  
Author(s):  
K. Vignarooban ◽  
Xinhai Xu ◽  
A. Arvay ◽  
K. Hsu ◽  
A.M. Kannan
Keyword(s):  
Heat Transfer ◽  
Power Systems ◽  
Solar Power ◽  
Concentrating Solar Power ◽  
Heat Transfer Fluids

scholarly journals Benefits of Solar/Fossil Hybrid Gas Turbine Systems

1979 ◽  
Author(s):  
H. S. Bloomfield
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Fuel Saving ◽  
Operational Mode ◽  
Fuel Savings ◽  
Cycle Systems ◽  
Potential Benefits ◽  
Near Term

The potential benefits of solar/fossil hybrid gas turbine power systems were assessed. Both retrofit and new systems were considered from the aspects of: cost of electricity, fuel conservation, operational mode, technology requirements, and fuels flexibility. Hybrid retrofit (repowering) of existing combustion (simple Brayton cycle) turbines can provide near-term fuel savings and solar experience, while new and advanced recuperated or combined-cycle systems may be an attractive fuel saving and economically competitive vehicle to transition from today’s gas- and oil-fired powerplants to other more abundant fuels.

Improving the efficiency of concentrating solar power systems

MRS Bulletin ◽  
2018 ◽  
Vol 43 (12) ◽  
pp. 920-921
Author(s):  
Eva Karatairi ◽  
Andrea Ambrosini
Keyword(s):  
Power Systems ◽  
Solar Power ◽  
Concentrating Solar Power
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