scholarly journals Supercritical CO2 Binary Mixtures for Recompression Brayton s-CO2 Power Cycles Coupled to Solar Thermal Energy Plants

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4050
Author(s):  
Paul Tafur-Escanta ◽  
Robert Valencia-Chapi ◽  
Ignacio López-Paniagua ◽  
Luis Coco-Enríquez ◽  
Javier Muñoz-Antón
Keyword(s):  
Molar Fraction ◽  
Solar Thermal ◽  
Working Fluid ◽  
Solar Thermal Energy ◽  
Power Cycles ◽  
Pressure Drops ◽  
Power Cycle ◽  
Thermal Plant ◽  
Heat Recuperator ◽  
The Impact

In this work, an evaluation and quantification of the impact of using mixtures based on supercritical carbon dioxide “s-CO2” (s-CO2/COS, s-CO2/H2S, s-CO2/NH3, s-CO2/SO2) are made as a working fluid in simple and complex recompression Brayton s-CO2 power cycle configurations that have pressure drops in their components. These cycles are coupled with a solar thermal plant with parabolic-trough collector (PTC) technology. The methodology used in the calculation performance is to establish values of the heat recuperator total conductance (UAtotal) between 5 and 25 MW/K. The main conclusion of this work is that the cycle’s efficiency has improved due to using s-CO2 mixtures as working fluid; this is significant compared to the results obtained using the standard fluid (pure s-CO2). Furthermore, a techno-economic analysis is carried out that compares each configuration’s costs using pure s-CO2 and a mixture of s-CO2/COS with a molar fraction (70/30), respectively, as working fluid where relevant results are obtained. These results show that the best configuration in terms of thermal efficiency and cost is the RCC-RH for pure sCO2 with values of 41.25% and 2811 $/kWe, while for the mixture sCO2/COS, the RCC-2RH configuration with values of 45.05% and 2621 $/kWe is optimal. Using the mixture costs 6.75% less than if it is used the standard fluid (s-CO2).

scholarly journals Supercritical CO2 Binary Mixtures for Recompression Brayton s-CO2 Power Cycles Coupled to Solar Thermal Energy Plants

2021 ◽  
Author(s):  
Paul Tafur-Escanta ◽  
Robert Valencia-Chapi ◽  
Ignacio López-Paniagua ◽  
Luis Coco-Enríquez ◽  
Javier Muñoz-Antón
Keyword(s):  
Molar Fraction ◽  
Solar Thermal ◽  
Working Fluid ◽  
Solar Thermal Energy ◽  
Power Cycles ◽  
Pressure Drops ◽  
Thermal Plant ◽  
Heat Recuperator ◽  
The Impact ◽  
Energy Plants

In this work, an evaluation and quantification of the impact of using mixtures based on Supercritical Carbon Dioxide "s-CO2" (s-CO2/COS, s-CO2/H2S, s-CO2/NH3, s-CO2/SO2) are made as a working fluid in simple and complex recompression Brayton s-CO2 power cycles configurations that have pressure drops in their components. These cycles are coupled to a solar thermal plant with parabolic-trough collector (PTC) technology. The methodology used in the calculation performance is to establish values of the heat recuperator total conductance (UAtotal) between 5 and 25 MW/K. The main conclusion of this work is that the cycle's efficiency has improved due to s-CO2 mixtures as working fluid; this is significant compared to that obtained using the standard fluid (pure s-CO2). Furthermore, a techno-economic analysis is carried out that compares each configuration's costs using pure s-CO2 and a mixture of s-CO2/COS with a molar fraction (70/30) respectively as working fluid where relevant results are obtained. These results show that the best configuration in terms of thermal efficiency and cost is the RCC-RH for pure sCO2 with values ​​of 41.25% and 2811 $/kWe, while for the mixture sCO2/COS, the RCC-2RH configuration with values ​​of 45, 05% and 2621 $/kWe is optimal. Using the mixture costs 6.75% less than if it is used the standard fluid (s-CO2).

scholarly journals Overall Efficiency of On-Site Production and Storage of Solar Thermal Energy

2021 ◽  
Vol 13 (3) ◽  
pp. 1360
Author(s):  
Teodora M. Șoimoșan ◽  
Ligia M. Moga ◽  
Livia Anastasiu ◽  
Daniela L. Manea ◽  
Aurica Căzilă ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Thermal Energy ◽  
Urban Areas ◽  
Renewable Energy Sources ◽  
Multicriteria Analysis ◽  
High Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
The Impact ◽  
And Storage

Harnessing renewable energy sources (RES) using hybrid systems for buildings is almost a deontological obligation for engineers and researchers in the energy field, and increasing the percentage of renewables within the energy mix represents an important target. In crowded urban areas, on-site energy production and storage from renewables can be a real challenge from a technical point of view. The main objectives of this paper are quantification of the impact of the consumer’s profile on overall energy efficiency for on-site storage and final use of solar thermal energy, as well as developing a multicriteria assessment in order to provide a methodology for selection in prioritizing investments. Buildings with various consumption profiles lead to achieving different values of performance indicators in similar configurations of storage and energy supply. In this regard, an analysis of the consumption profile’s impact on overall energy efficiency, achieved in the case of on-site generation and storage of solar thermal energy, was performed. The obtained results validate the following conclusion: On-site integration of solar systems allowed the consumers to use RES at the desired coverage rates, while restricted by on-site available mounting areas for solar fields and thermal storage, under conditions of high energy efficiencies. In order to segregate the results and support optimal selection, a multicriteria analysis was carried out, having as the main criteria the energy efficiency indicators achieved by hybrid heating systems.

Performance Analysis and Comparison Study of Transcritical Power Cycles Using CO2-Based Mixtures as Working Fluids

2016 ◽  
Author(s):  
Jiaxi Xia ◽  
Jiangfeng Wang ◽  
Pan Zhao ◽  
Dai Yiping
Keyword(s):  
Critical Temperature ◽  
Parametric Optimization ◽  
Design Parameters ◽  
Working Fluid ◽  
Comparison Study ◽  
Software Environment ◽  
Working Fluids ◽  
Power Cycles ◽  
Power Cycle ◽  
Thermodynamic Performance

CO2 in a transcritical CO2 cycle can not easily be condensed due to its low critical temperature (304.15K). In order to increase the critical temperature of working fluid, an effective method is to blend CO2 with other refrigerants to achieve a higher critical temperature. In this study, a transcritical power cycle using CO2-based mixtures which blend CO2 with other refrigerants as working fluids is investigated under heat source. Mathematical models are established to simulate the transcritical power cycle using different CO2-based mixtures under MATLAB® software environment. A parametric analysis is conducted under steady-state conditions for different CO2-based mixtures. In addition, a parametric optimization is carried out to obtain the optimal design parameters, and the comparisons of the transcritical power cycle using different CO2-based mixtures and pure CO2 are conducted. The results show that a raise in critical temperature can be achieved by using CO2-based mixtures, and CO2-based mixtures with R32 and R22 can also obtain better thermodynamic performance than pure CO2 in transcritical power cycle. What’s more, the condenser area needed by CO2-based mixture is smaller than pure CO2.

System and component modelling of a low temperature solar thermal energy conversion cycle

2013 ◽  
Vol 24 (4) ◽  
pp. 51-62
Author(s):  
Shadreck M. Situmbeko ◽  
Freddie L. Inambao
Keyword(s):  
Low Temperature ◽  
Solar Energy ◽  
Thermal Energy ◽  
Electrical Power ◽  
Solar Thermal ◽  
Working Fluid ◽  
Small Scale ◽  
Solar Thermal Energy ◽  
Solar Field ◽  
Conversion Technology

Solar thermal energy (STE) technology refers to the conversion of solar energy to readily usable energy forms. The most important component of a STE technology is the collectors; these absorb the shorter wavelength solar energy (400-700nm) and convert it into usable, longer wavelength (about 10 times as long) heat energy. Depending on the quality (temperature and intensity) of the resulting thermal energy, further conversions to other energy forms such as electrical power may follow. Currently some high temperature STE technologies for electricity production have attained technical maturity; technologies such as parabolic dish (commercially available), parabolic trough and power tower are only hindered by unfavourable market factors including high maintenance and operating costs. Low temperature STEs have so far been restricted to water and space heating; however, owing to their lower running costs and almost maintenance free operation, although operating at lower efficiencies, may hold a key to future wider usage of solar energy. Low temperature STE conversion technology typically uses flat plate and low concentrating collectors such as parabolic troughs to harness solar energy for conversion to mechanical and/or electrical energy. These collector systems are relatively cheaper, simpler in construction and easier to operate due to the absence of complex solar tracking equipment. Low temperature STEs operate within temperatures ranges below 300oC. This research work is geared towards developing feasible low temperature STE conversion technology for electrical power generation. Preliminary small-scale concept plants have been designed at 500Wp and 10KWp. Mathematical models of the plant systems have been developed and simulated on the EES (Engineering Equation Solver) platform. Fourteen candidate working fluids and three cycle configurations have been analysed with the models. The analyses included a logic model selector through which an optimal conversion cycle configuration and working fluid mix was established. This was followed by detailed plant component modelling; the detailed component model for the solar field was completed and was based on 2-dimensional segmented thermal network, heat transfer and thermo fluid dynamics analyses. Input data such as solar insolation, ambient temperature and wind speed were obtained from the national meteorology databases. Detailed models of the other cycle components are to follow in next stage of the research. This paper presents findings of the system and solar field component.

A Systematic Comparison and Multi-Objective Optimisation of Humid Power Cycles: Part II—Economics

2008 ◽  
Author(s):  
Ronan M. Kavanagh ◽  
Geoffrey T. Parks
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Search Algorithm ◽  
Working Fluid ◽  
Specific Work ◽  
Power Cycles ◽  
System Parameters ◽  
Multi Objective ◽  
Fluid Properties ◽  
The Impact

The STIG, HAT and TOPHAT cycles lie at the centre of the debate on which humid power cycle will deliver optimal performance when applied to an aero-derivative gas turbine and, indeed, when such cycles will be implemented. Of these humid cycles, it has been claimed that the TOPHAT cycle has the highest efficiency and specific work, followed closely by the HAT (Humid Air Turbine) and then the STIG (STeam Injected Gas turbine) cycle. In this study, the systems have been simulated using consistent thermodynamic and economic models for the components and working fluid properties, allowing a consistent and non-biased appraisal of these systems. Part 1 of these two papers focussed on the thermodynamic performance and the impact of the system parameters on the performance, part 2 studies the economic performance of these cycles. The three humid power systems and up to ten system parameters are optimised using a multi-objective Tabu Search algorithm, developed in the Cambridge Engineering Design Centre.

A Review on Experimental and Numerical Investigations on Using Nanofluid in Volumetric Solar Energy Collectors

2014 ◽  
Author(s):  
Siamak Mirmasoumi ◽  
Mohammad Pourgol-Mohammad
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Radiant Energy ◽  
Solar Thermal ◽  
Working Fluid ◽  
Steam Generation ◽  
Solar Thermal Energy ◽  
Solar Absorption ◽  
Advantages And Disadvantages ◽  
Solar Power Plants

By a simple research in the scholarly articles, it can be realized that the tendency to using solar thermal energy has risen in the recent years due to its many reasonable advantages. In conventional solar thermal systems, HTFs (Heat Transfer Fluids) are pumped through the piping of a solar collector and after absorbing the solar radiant energy conveys it to water to make steam. No need to say that this method contains some losses via all methods of heat transfer. To solve this problem, researchers have shown that with direct steam generation, in which working fluid directly absorbs solar thermal and becomes vapor, solar power plants have the potential to be more productive. However, the aforesaid conventional HTFs don’t have efficient enough thermal properties and need to be improved. For this reason using nanofluid has become to some extent popular in heat transfer facilities like solar thermal collectors. In the present study, we are going to identify the advantages and disadvantages of using nanoparticles in direct solar absorption systems (DSASs). To achieve this, a general review on the experimental and numerical studies in this field is done. Additionally some of the most effective particles for such a special case, in which particles should have good radiative characteristics, are introduced. Finally, after discussion about the highlighted challenges of using nanofluids in DSASs, some helpful suggestions to overcome these problems will be presented.

scholarly journals Corrosion and Erosion Behavior in Supercritical CO2 Power Cycles

2014 ◽  
Author(s):  
Darryn Fleming ◽  
Alan Kruizenga ◽  
James Pasch ◽  
Tom Conboy ◽  
Matt Carlson
Keyword(s):  
Carbon Dioxide ◽  
Stainless Steel ◽  
Intergranular Corrosion ◽  
Supercritical Co2 ◽  
Power Production ◽  
Operating Conditions ◽  
Working Fluid ◽  
Power Cycles ◽  
Power Cycle ◽  
Potential Issue

Supercritical Carbon Dioxide (S-CO2) is emerging as a potential working fluid in power-production Brayton cycles. As a result, concerns have been raised regarding fluid purity within the power cycle loops. Additionally, investigations into the longevity of the S-CO2 power cycle materials are being conducted to quantify the advantages of using S-CO2 versus other fluids, since S-CO2 promises substantially higher efficiencies. One potential issue with S-CO2 systems is intergranular corrosion [1]. At this time, Sandia National Laboratories (SNL) is establishing a materials baseline through the analysis of 1) “as received” stainless steel piping, and 2) piping exposed to S-CO2 under typical operating conditions with SNL’s Brayton systems. Results from ongoing investigations are presented. A second issue that SNL has discovered involves substantial erosion in the turbine blade and inlet nozzle. It is believed that this is caused by small particulates that originate from different materials around the loop that are entrained by the S-CO2 to the nozzle, where they impact the inlet nozzle vanes, causing erosion. We believe that, in some way, this is linked to the purity of the S-CO2, the corrosion contaminants, and the metal particulates that are present in the loop and its components.

System and Component Transport Considerations of Micro-Pin Based Solar Receivers With High Temperature Gaseous Working Fluids

2018 ◽  
Author(s):  
Brian M. Fronk ◽  
Saad A. Jajja
Keyword(s):  
High Temperature ◽  
Distribution System ◽  
Energy System ◽  
Operating Conditions ◽  
Solar Thermal ◽  
System Level ◽  
Working Fluid ◽  
Solar Thermal Energy ◽  
Working Fluids ◽  
Compressor Power

This paper explores the interactions between micro-pin concentrated receiver designs with overall solar thermal energy system performance, with different operating conditions, working fluid, and required materials of construction. A 320 MW thermal plant coupled to a 160 MW electric sCO2 Brayton cycle is considered as the baseline. The circulating fluid enters the receiver at 550°C, and leaves at 720°C. The thermal storage/power block are located 150 m from the receiver at the base of the receiver tower. A resistance network based thermal and hydraulic model is used to predict heat transfer and pressure drop performance of the micro-pin receiver. This output of this model is coupled to a system level model of the pressure loss and compressor power required in the remainder of the high temperature gas loop. Overall performance is investigated for supercritical carbon dioxide and helium as working fluids, at pressures from 7.5 to 25 MPa, and at delivery temperatures of 720°C. The results show that by modifying pin depth and flow lengths, there are design spaces for micro-pin devices that can provide high thermal performance without significantly reducing the overall solar thermal system output at lower operating pressures. Use of lower pressure fluids enables lower cost materials of construction in the piping and distribution system, reducing the cost of electricity.

A Systematic Comparison and Multi-Objective Optimisation of Humid Power Cycles: Part I—Thermodynamics

2008 ◽  
Author(s):  
Ronan M. Kavanagh ◽  
Geoffrey T. Parks
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Search Algorithm ◽  
Working Fluid ◽  
Specific Work ◽  
Power Cycles ◽  
System Parameters ◽  
Multi Objective ◽  
Fluid Properties ◽  
The Impact

The STIG, HAT and TOPHAT cycles lie at the centre of the debate on which humid power cycle will deliver optimal performance when applied to an aero-derivative gas turbine and, indeed, when such cycles will be implemented. Of these humid cycles, it has been claimed that the TOPHAT cycle has the highest efficiency and specific work, followed closely by the HAT (Humid Air Turbine) and then the STIG (STeam Injected Gas turbine) cycle. In this study, the systems have been simulated using consistent thermodynamic and economic models for the components and working fluid properties, allowing a consistent and non-biased appraisal of these systems. Part 1 of these two papers focusses purely on the thermodynamic performance and the impact of the system parameters on the performance, part 2 will study the economic performance. The three humid power systems and up to ten system parameters are optimised using a multi-objective Tabu Search algorithm, developed in the Cambridge Engineering Design Centre.

Sign in / Sign up

Export Citation Format

Share Document