scholarly journals Assessment of Solar Power Tower Driven Ultrasupercritical Steam Cycles Applying Tubular Central Receivers With Varied Heat Transfer Media

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Csaba Singer ◽  
Reiner Buck ◽  
Robert Pitz-Paal ◽  
Hans Müller-Steinhagen
Keyword(s):  
Heat Transfer ◽  
Cost Reduction ◽  
Power Plants ◽  
Reduction Potential ◽  
Solar Power ◽  
Power Level ◽  
Scale Up ◽  
Reference Case ◽  
Solar Power Tower ◽  
Significant Cost Reduction

For clean and efficient electric power generation, the combination of solar power towers (SPTs) with ultrasupercritical steam cycle power plants could be the next development step. The methodology of the European concentrated solar thermal roadmap study was used to predict the annual performance and the cost reduction potential of this option applying tubular receivers with various appropriate high temperature heat transfer media (HTM). For the assessment, an analytical model of the heat transfer in a parametric 360 deg cylindrical and tubular central receiver was developed to examine the receiver’s efficiency characteristics. The receiver’s efficiency characteristics, which are based on different irradiation levels relative to the receiver’s design point, are, then, used to interpolate the receiver’s thermal efficiency in an hourly based annual calculation of one typical year that is defined by hourly based real measurements of the direct normal irradiance and the ambient temperature. Applying appropriate cost assumptions from literature, the levelized electricity costs (LEC) were estimated for each considered SPT concept and compared with the reference case, which is a scale-up of the state of the art molten salt concept. The power level of all compared concepts and the reference case is 50 MWel. The sensitivity of the specific cost assumptions for the LEC was evaluated for each concept variation. No detailed evaluation was done for the thermal storage but comparable costs were assumed for all cases. The results indicate a significant cost reduction potential of up to 15% LEC reduction in the liquid metal HTM processes. Due to annual performance based parametric studies of the number of receiver panels and storage capacity, the results also indicate the optimal values of these parameters concerning minimal LEC.

scholarly journals Assessment of Solar Power Tower Driven Ultra Supercritical Steam Cycles Applying Tubular Central Receivers With Varied Heat Transfer Media

2009 ◽  
Author(s):  
Cs. Singer ◽  
R. Buck ◽  
R. Pitz-Paal ◽  
H. Mu¨ller-Steinhagen
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Cost Reduction ◽  
Power Plants ◽  
Reduction Potential ◽  
Solar Power ◽  
Liquid Metals ◽  
Specific Investment ◽  
Temperature Heat ◽  
Electricity Costs

In commercial power plant technology, the market introduction of ultra supercritical (USC) steam cycle power plants with steam parameters around 350bar and 720°C is the next development step. USC steam cycles are also proposed to decrease the levelized electricity costs of future solar power towers due to their highly efficient energy conversion. A 55% thermal efficiency with decreased specific investment costs is within the potential of USC steam cycles. The required process parameters can be achieved using nickel based alloys in the solar receiver, the tubing and other plant components. For solar tower applications, appropriate high temperature heat transfer media (HTM), high temperature heat exchangers and storage options are additionally required. Using the current development for molten salt power towers (Solar Tres) as a reference, several tower concepts with USC power plants were compared. The ECOSTAR methodology provided by [1] was applied for predicting the cost reduction potential and the annual performance of these power tower concepts applying tubular receivers with various HTM. The considered HTM include alkali nitrate salts, alkali chloride salts and liquid metals such as a Bi-Pb eutectic, tin or sodium. For the assessment, an analytical model of the heat transfer in a parametric 360° cylindrical, tubular central receiver was developed to examine the receiver characteristics for different geometries. The sensitivity of the specific cost assumptions for the levelized electricity costs (LEC) was evaluated for each concept variation. No detailed evaluation was done for the thermal storage, but comparable costs were assumed for all cases. The results indicate a significant cost reduction potential for the liquid metal HTM processes.

Economic Potential of Innovative Receiver Concepts With Different Solar Field Configurations for Supercritical Steam Cycles

2011 ◽  
Author(s):  
Cs. Singer ◽  
R. Buck ◽  
R. Pitz-Paal ◽  
H. Mu¨ller-Steinhagen
Keyword(s):  
Molten Salt ◽  
Cost Reduction ◽  
Reduction Potential ◽  
Power Level ◽  
Direct Absorption ◽  
Reference Case ◽  
Levelized Cost Of Electricity ◽  
Absorber Structure ◽  
Solar Field ◽  
Lateral Area

The cost reduction potential of solar power towers (SPT) is an important issue concerning its market introduction. Raising the steam process temperature and pressure can lead to a cost reduction due to increased overall plant efficiency. Thus, for new receiver configurations a supercritical steam cycle operated at 300 bar / 600°C / 610°C live steam conditions was assumed. The considered systems include innovative direct absorption receivers, either with conventional or beam down heliostat field layouts. For the beam down option the receiver is assumed to be a cylindrical vessel with a flow-through porous absorber structure at the internal lateral area of the cylinder. The direct absorption receiver option consists of a cylindrical barrel with downwards oriented aperture, whose absorber structure at the internal lateral area is cooled by a molten salt film. For the assessment, CFD based methods were developed to be able to examine the receiver efficiency characteristics. Based on the receiver thermal efficiency characteristics and the solar field characteristics the annual performance is evaluated using hourly time series. The assessment methodology is based on the European Concentrated Solar Thermal Roadmap (ECOSTAR) study and enables the prediction of the annual performance and the levelized cost of electricity (LCOE). Applying appropriate cost assumptions from literature the LCOE were estimated for each considered SPT concept and compared to tubular receiver concepts with molten salt and liquid metal cooling. The power level of the compared concepts and the reference case is 200 MWel. The sensitivity of the specific cost assumptions was analyzed. No detailed evaluation was done for the thermal storage, but comparable storage utilization and costs were assumed for all cases. At optimized plant parameters the results indicate a LCOE reduction potential of up to 0.5% for beam down and of up to 7.2% for the direct absorption receiver compared to today’s state of the art molten salt solar tower technology.

Economic Potential of Innovative Receiver Concepts With Different Solar Field Configurations for Supercritical Steam Cycles

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Csaba Singer ◽  
Reiner Buck ◽  
Robert Pitz-Paal ◽  
Hans Müller-Steinhagen
Keyword(s):  
Molten Salt ◽  
Cost Reduction ◽  
Reduction Potential ◽  
Power Level ◽  
Direct Absorption ◽  
Reference Case ◽  
Levelized Cost Of Electricity ◽  
Absorber Structure ◽  
Solar Field ◽  
Lateral Area

The cost reduction potential of solar power towers (SPT) is an important issue concerning its market introduction. Raising the steam process temperature and pressure can lead to a cost reduction due to increased overall plant efficiency. Thus, for new receiver configurations, a supercritical steam cycle operated at 300 bar/600 °C/610 °C live steam conditions was assumed. The considered systems include innovative direct absorption receivers, either with conventional or beam down heliostat field layouts. For the beam down option, the receiver is assumed to be a cylindrical vessel with a flow-through porous absorber structure at the internal lateral area of the cylinder. The direct absorption receiver option consists of a cylindrical barrel with downwards oriented aperture, whose absorber structure at the internal lateral area is cooled by a molten salt film. For the assessment, CFD based methods are developed and able to examine the receiver efficiency characteristics. Based on the receiver thermal efficiency characteristics and the solar field characteristics, the annual performance is evaluated using hourly time series. The assessment methodology is based on the European Concentrated Solar Thermal Roadmap (ECOSTAR) study and enables the prediction of the annual performance and the levelized cost of electricity (LCOE). Applying appropriate cost assumptions from literature, the LCOE are estimated for each considered SPT concept and compared to tubular receiver concepts with molten salt and liquid metal cooling. The power level of the compared concepts and the reference case is 200 MWel. The sensitivity of the specific cost assumptions is analyzed. No detailed evaluation is done for the thermal storage, but comparable storage utilization and costs are assumed for all cases. At optimized plant parameters, the results indicate a LCOE reduction potential of up to 0.5% for beam down and of up to 7.2% for the direct absorption receiver compared to today's state of the art molten salt solar tower technology.

Analyses of Thermal Performance of Solar Power Tower Station Based on a Supercritical CO2 Brayton Cycle

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Lijun Fang ◽  
Yang Li ◽  
Xue Yang ◽  
Zeliang Yang
Keyword(s):  
Heat Transfer ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Solar Power ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Levelized Cost Of Electricity ◽  
Heat Receiver ◽  
Overall Performance ◽  
Solar Power Tower

Abstract Concentrating solar power (CSP) technology, possessing an inherent capacity to couple with energy storage ideally, attracts a great deal of attention nowadays. However, these power plants with various types of CSP system still cannot compete with the traditional thermal power plants in terms of levelized cost of electricity (LCOE), and their potential for utilizing clear and renewable solar energy cannot be overestimated. To improve the total efficiency of the solar power tower (SPT) plant is the key factor for its development. In this present paper, a SPT plant based on an S-CO2 Brayton cycle (with S-CO2 serving as heat transfer and working fluid) is proposed. A numerical simulation is carried out to calculate the effects of key operating parameters, including power cycle and subsystem parameters, on the overall performance of the SPT plant. The results show that there is an optimum value for the compression ratio for the SPT plant. For the heat receiver, the trends of exergy and thermal efficiency varying with turbine inlet temperature are reversed, because of the significant energy loss caused by high temperature of the surface of the heat receiver. As for the overall performance, the SPT plant proposed in this paper is better than other SPT plants based on a steam Rankine system and an S-CO2 Brayton system with molten salt serving as heat transfer fluid (HTF) operating under the similar condition. Its overall thermal efficiency is 1.04% and 3.42% higher than that of two other SPT plants, respectively.

scholarly journals Comparative Modeling of a Parabolic Trough Collectors Solar Power Plant with MARS Models

Energies ◽  
2017 ◽  
Vol 11 (1) ◽  
pp. 37 ◽  
Author(s):  
Jose Rogada ◽  
Lourdes Barcia ◽  
Juan Martinez ◽  
Mario Menendez ◽  
Francisco de Cos Juez
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Power Plant ◽  
Solar Radiation ◽  
Thermal Energy ◽  
Power Plants ◽  
Solar Power ◽  
Rankine Cycle ◽  
Heat Transfer Fluid ◽  
Solar Field

Power plants producing energy through solar fields use a heat transfer fluid that lends itself to be influenced and changed by different variables. In solar power plants, a heat transfer fluid (HTF) is used to transfer the thermal energy of solar radiation through parabolic collectors to a water vapor Rankine cycle. In this way, a turbine is driven that produces electricity when coupled to an electric generator. These plants have a heat transfer system that converts the solar radiation into heat through a HTF, and transfers that thermal energy to the water vapor heat exchangers. The best possible performance in the Rankine cycle, and therefore in the thermal plant, is obtained when the HTF reaches its maximum temperature when leaving the solar field (SF). In addition, it is necessary that the HTF does not exceed its own maximum operating temperature, above which it degrades. The optimum temperature of the HTF is difficult to obtain, since the working conditions of the plant can change abruptly from moment to moment. Guaranteeing that this HTF operates at its optimal temperature to produce electricity through a Rankine cycle is a priority. The oil flowing through the solar field has the disadvantage of having a thermal limit. Therefore, this research focuses on trying to make sure that this fluid comes out of the solar field with the highest possible temperature. Modeling using data mining is revealed as an important tool for forecasting the performance of this kind of power plant. The purpose of this document is to provide a model that can be used to optimize the temperature control of the fluid without interfering with the normal operation of the plant. The results obtained with this model should be necessarily contrasted with those obtained in a real plant. Initially, we compare the PID (proportional–integral–derivative) models used in previous studies for the optimization of this type of plant with modeling using the multivariate adaptive regression splines (MARS) model.

scholarly journals Solar Thermal Power: Appraisal of Solar Power Towers

2018 ◽  
Vol 225 ◽  
pp. 04003
Author(s):  
Hashem Shatnawi ◽  
Chin Wai Lim ◽  
Firas Basim Ismail
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Solar Power ◽  
Thermal Power ◽  
Tube Material ◽  
Power Cycles ◽  
Solar Thermal Power ◽  
Central Receiver ◽  
Receiver System ◽  
Solar Power Tower

This study delves into several engineering procedures related to solar power tower plants. These installations come with central receiver system technologies and high-temperature power cycles. Besides a summary emphasizing on the fundamental components of a solar power tower, this paper also forwards a description of three receiver designs. Namely, these are the tubular receiver, the volumetric receiver and the direct absorber receiver. A variety of heat transfer mediums were assessed, while a comprehensive explanation was provided on the elements of external solar cylindrical receivers. This explanation covers tube material, molten salt, tube diameter and heat flux.

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