scholarly journals Techno-Economic Comparison of Solar-Driven SCO2 Brayton Cycles Using Component Cost Models Baselined With Vendor Data and Estimates

2017 ◽  
Author(s):  
Matthew D. Carlson ◽  
Bobby M. Middleton ◽  
Clifford K. Ho
Keyword(s):  
Power Systems ◽  
Conversion Efficiency ◽  
High Efficiency ◽  
Cost Data ◽  
Brayton Cycle ◽  
Cost Models ◽  
Economic Optimization ◽  
Mixed Gas ◽  
Power Cycles ◽  
Power Block

Supercritical carbon dioxide (sCO2) Brayton power cycles have the potential to significantly improve the economic viability of concentrating solar power (CSP) plants by increasing the thermal to electric conversion efficiency from around 35% using high-temperature steam Rankine systems to above 45% depending on the cycle configuration. These systems are the most likely path toward achieving the Department of Energy’s (DOE) Office of Energy Efficiency and Renewable Energy (EERE) SunShot targets for CSP tower thermal to electric conversion efficiency above 50% with dry cooling to air at 40 °C and a power block cost of less than 900 $/kWe. Many studies have been conducted to optimize the performance of various sCO2 Brayton cycle configurations in order to achieve high efficiency, and a few have accounted for drivers of cost such as equipment size in the optimization, but complete techno-economic optimization has not been feasible because there are no validated models relating component performance and cost. Reasonably accurate component cost models exist from several sources for conventional equipment including turbines, compressors, and heat exchangers for use in rough order of magnitude cost estimates when assembling a system of conventional equipment. However, cost data from fabricated equipment relevant to sCO2 Brayton cycles is very limited in terms of both supplier variety and performance level with most existing data in the range of 1 MWe power cycles or smaller systems, a single completed system around 7 MWe by Echogen Power Systems, and numerous ROM estimates based on preliminary designs of equipment for 10 MWe systems. This data is highly proprietary as the publication of individual data by any single supplier would damage their market position by potentially allowing other vendors to undercut their stated price rather than competing on reduced manufacturing costs. This paper describes one approach to develop component cost models in order to enable the techno-economic optimization activities needed to guide further research and development while protecting commercially proprietary information from individual vendors. Existing cost models were taken from literature for each major component used in different sCO2 Brayton cycle configurations and adjusted for their magnitude to fit the limited vendor cost data and estimates available. A mean fit curve was developed for each component and used to calculate updated cost comparisons between previously-reviewed sCO2 Brayton cycle configurations for CSP applications including simple recuperated, recompression, cascaded, and mixed-gas combined bifurcation with intercooling cycles. These fitting curves represent an average of the assembled vendor data without revealing any individual vendor cost, and maintain the scaling behavior with performance expected from similar equipment found in literature.

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.

Proposal for a Highly Efficient Cogeneration System Using an Atmospheric Pressure Turbine Coupled With Biomass Gasification

2009 ◽  
Author(s):  
Y. Tsujikawa ◽  
K. Kaneko ◽  
N. Muraoka
Keyword(s):  
Power Systems ◽  
Atmospheric Pressure ◽  
Energy Efficient ◽  
High Efficiency ◽  
Brayton Cycle ◽  
Small Plant ◽  
Combustible Gas ◽  
Cogeneration System ◽  
Expansion Cooling ◽  
Made In

Biomass is a significant renewable energy source. The conversion of woody biomass into a combustible gas provides the opportunity to enhance the efficiency of biomass-based power systems, and allows solid fuels to be used in high-efficiency power generation processes. This paper discusses the energy efficient utilization of biomass by turbo machines under unpressurized conditions, working with the inverted Brayton cycle in which turbine expansion, cooling by heat exchanger and draft by compressor are made in an open cycle mode. We call this an “atmospheric pressure turbine (APT)”. Thermodynamic analysis has shown that an electric efficiency up to 25% (HHV) and a total energy efficiency of more than 80% (HHV) are expected for combined heat and power applications even at small plant capacities (∼40 kW).

Reduction of Combustion Irreversibility in a Gas Turbine Power Plant Through Off-Gas Recycling

1995 ◽  
Vol 117 (1) ◽  
pp. 24-30 ◽  
Author(s):  
S. P. Harvey ◽  
K. F. Knoche ◽  
H. J. Richter
Keyword(s):  
Gas Turbine ◽  
Conversion Efficiency ◽  
Power Plants ◽  
High Efficiency ◽  
Energy Conversion Efficiency ◽  
Power Cycles ◽  
Exhaust Gases ◽  
Exhaust Heat ◽  
Simplifying Assumptions ◽  
Overall Efficiency

Combustion in conventional fossil-fueled power plants is highly irreversible, resulting in poor overall energy conversion efficiency values (less than 40 percent in many cases). The objective of this paper is to discuss means by which this combustion irreversibility might be reduced in gas turbine power cycles, and the conversion efficiency thus improved upon. One such means is thermochemical recuperation of exhaust heat. The proposed cycle recycles part of the exhaust gases, then mixes them with fuel prior to injection into a reformer. The heat required for the endothermic reforming reactions is provided by the hot turbine exhaust gases. Assuming state-of-the-art technology, and making a number of simplifying assumptions, an overall efficiency of 65.4 percent was attained for the cycle, based on the lower heating value (LHV) of the methane fuel. The proposed cycle is compared to a Humid Air Turbine (HAT) cycle with similar features that achieves an overall efficiency of 64.0 percent. The gain in cycle efficiency that can be attributed to the improved fuel oxidation process is 1.4 percentage points. Compared to current high-efficiency gas turbine cycles, the high efficiency of both cycles studied therefore results mainly from the use of staged compression and expansion with intermediate cooling and reheating, respectively.

scholarly journals Thermo-economic optimization of supercritical CO2 Brayton cycle on the design point for application in solar power tower system

2021 ◽  
Vol 242 ◽  
pp. 01002
Author(s):  
Tianye Liu ◽  
Jingze Yang ◽  
Zhen Yang ◽  
Yuanyuan Duan
Keyword(s):  
Ambient Temperature ◽  
Thermal Efficiency ◽  
High Efficiency ◽  
Solar Power ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Economic Optimization ◽  
Compressor Inlet ◽  
Solar Power Tower ◽  
Tower System

The supercritical CO2 Brayton cycle integrated with a solar power tower system has the advantages of high efficiency, compact cycle structure, strong scalability, and great power generation potential, which can positively deal with the energy crisis and global warming. The selection and optimization of design points are very important for actual operating situations. In this paper, the thermodynamic and economic models of the 10 MWe supercritical CO2 Brayton cycle for application in solar power tower system are established. Multi-objective optimizations of the simple recuperative cycle, reheating cycle, and recompression cycle at different compressor inlet temperature are completed. The thermal efficiency and the levelized energy cost are selected as the fitness functions. The ranges of the optimal compressor inlet pressure and reheating pressure on the Pareto frontier are analyzed. Finally, multiobjective optimizations and analysis of the supercritical CO2 Brayton cycle at different ambient temperature are carried out. This paper investigates the influence of the compressor inlet temperature and ambient temperature on the thermal efficiency and economic performance of the supercritical CO2 Brayton cycle.

High Efficiency Gas Turbine Based Power Cycles—A Study of the Most Promising Solutions: Part 1—A Review of the Technology

2008 ◽  
Author(s):  
Rakesh K. Bhargava ◽  
Michele Bianchi ◽  
Stefano Campanari ◽  
Andrea De Pascale ◽  
Giorgio Negri di Montenegro ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
High Efficiency ◽  
Water Injection ◽  
Thermodynamic Cycle ◽  
Brayton Cycle ◽  
Molten Carbonate ◽  
Power Cycles

Commercially available gas turbines have been mostly designed based on the simple Brayton cycle and despite the enormous advancements made in their components design, materials technology, blade cooling methods, etc., thermodynamic performance achievable for this simple cycle is limited. Numerous variants to the basic Brayton cycle viz., Recuperated (REC), Inter-Cooled (IC), Re-Heat (RH), steam injected (STIG) and their combinations have been proposed, extensively discussed in the literature since the early stages of gas turbine development and few of them have been successfully implemented. New variants not yet implemented in commercial engines and still in various stages of the development with potential for additional performance improvement are: advanced Steam Injected cycle and its variants (such as Inter-cooled Steam Injected, (ISTIG)), Recuperated Water Injection cycle (RWI), Humidified Air Turbine (HAT) cycle and Cascaded Humidified Advanced Turbine (CHAT) cycle, Brayton cycle with high temperature fuel cells (Molten Carbonate Fuel Cells (MCFC) and Solid Oxide Fuel Cells (SOFC)) and their combinations with the available modified Brayton cycles. The main objective of this paper (Part 1 of the two-part paper) is to provide a comprehensive review of high performance (with most promising solutions) complex gas turbine cycles, describing their main characteristics, benefits and drawbacks in comparison with the simple Brayton cycle. Detailed parametric thermodynamic cycle analyses for the selected high efficiency cycles under development are presented in Part 2 of this paper.

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.

Gas Turbine “Solarization”-Modifications for Solar/Fuel Hybrid Operation

2004 ◽  
Vol 126 (3) ◽  
pp. 872-878 ◽  
Author(s):  
Uri Fisher ◽  
Chemi Sugarmen ◽  
Arik Ring ◽  
Joseph Sinai
Keyword(s):  
Gas Turbine ◽  
Experimental Test ◽  
Cost Reduction ◽  
Gas Turbines ◽  
High Efficiency ◽  
Brayton Cycle ◽  
Test Results ◽  
Solar Fuel ◽  
Hardware Cost ◽  
Power Block

Achieving solar produced electricity at a reasonable price with large utility-size units is a worldwide goal. This can be achieved by high efficiency systems and hardware cost reduction. The ORMAT Brayton cycle solar hybrid gas turbine is a step in this direction. ORMAT took part in several solar projects in which it contributed to the “solarization” of the complete power block. This paper describes the main tasks involved in solarization, and includes experimental test results where helicopter turboshaft gas turbines were used. The paper reviews several solar projects and mainly the SOLGATE project during the years 2001–2003. During 2002–2003 the turbine was operated in Spain, combined with three volumetric receivers. The initial goal of achieving 800°C at the receiver outlet was achieved and is reported on below. The successful tests have encouraged the continuation of work using gas turbines of 10 MW and above, which has already commenced.

scholarly journals Eco-Emission Analysis of Multi-Carrier Microgrid Integrated with Compressed Air and Power-to-Gas Energy Storage Technologies

2021 ◽  
Vol 13 (9) ◽  
pp. 4681
Author(s):  
Khashayar Hamedi ◽  
Shahrbanoo Sadeghi ◽  
Saeed Esfandi ◽  
Mahdi Azimian ◽  
Hessam Golmohamadi
Keyword(s):  
Energy Storage ◽  
Power Systems ◽  
High Efficiency ◽  
Objective Assessment ◽  
Energy Systems ◽  
Vital Role ◽  
Compressed Air ◽  
Emission Analysis ◽  
Multi Objective ◽  
Power To Gas

Growing concerns about global greenhouse gas emissions have led power systems to utilize clean and highly efficient resources. In the meantime, renewable energy plays a vital role in energy prospects worldwide. However, the random nature of these resources has increased the demand for energy storage systems. On the other hand, due to the higher efficiency of multi-energy systems compared to single-energy systems, the development of such systems, which are based on different types of energy carriers, will be more attractive for the utilities. Thus, this paper represents a multi-objective assessment for the operation of a multi-carrier microgrid (MCMG) in the presence of high-efficiency technologies comprising compressed air energy storage (CAES) and power-to-gas (P2G) systems. The objective of the model is to minimize the operation cost and environmental pollution. CAES has a simple-cycle mode operation besides the charging and discharging modes to provide more flexibility in the system. Furthermore, the demand response program is employed in the model to mitigate the peaks. The proposed system participates in both electricity and gas markets to supply the energy requirements. The weighted sum approach and fuzzy-based decision-making are employed to compromise the optimum solutions for conflicting objective functions. The multi-objective model is examined on a sample system, and the results for different cases are discussed. The results show that coupling CAES and P2G systems mitigate the wind power curtailment and minimize the cost and pollution up to 14.2% and 9.6%, respectively.

scholarly journals High-Efficiency, Dual-Band Beam Splitter Based on an All-Dielectric Quasi-Continuous Metasurface

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3184
Author(s):  
Jing Li ◽  
Yonggang He ◽  
Han Ye ◽  
Tiesheng Wu ◽  
Yumin Liu ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Conversion Efficiency ◽  
Antenna Arrays ◽  
Beam Splitter ◽  
High Efficiency ◽  
Visible Region ◽  
Polarized Light ◽  
Dual Band ◽  
Phase Gradient ◽  
Total Transmission

Metasurface-based beam splitters attracted huge interest for their superior properties compared with conventional ones made of bulk materials. The previously reported designs adopted discrete metasurfaces with the limitation of a discontinuous phase profile. In this paper, we propose a dual-band beam splitter, based on an anisotropic quasi-continuous metasurface, by exploring the optical responses under x-polarized (with an electric field parallel to the direction of the phase gradient) and y-polarized incidences. The adopted metasurface consists of two identical trapezoidal silicon antenna arrays with opposite spatial variations that lead to opposite phase gradients. The operational window of the proposed beam splitter falls in the infrared and visible region, respectively, for x- and y-polarized light, resulting from the different mechanisms. When x-polarized light is incident, the conversion efficiency and total transmission of the beam splitter remains higher than 90% and 0.74 within the wavelength range from 969 nm to 1054 nm, respectively. In this condition, each array can act as a beam splitter of unequal power. For y-polarized incidence, the maximum conversion efficiency and transmission reach approximately 100% and 0.85, while the values remain higher than 90% and 0.65 in the wavelength range from 687 nm to 710 nm, respectively. In this case, each array can be viewed as an effective beam deflector. We anticipate that it can play a key role in future integrated optical devices.

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