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.

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.

High-Temperature Heat Transport and Storage Using LBE Alloy for Concentrated Solar Power System

2015 ◽  
Author(s):  
Jin-Soo Kim ◽  
Adrian Dawson ◽  
Robert Wilson ◽  
Kishore Venkatesan ◽  
Wesley Stein
Keyword(s):  
High Temperature ◽  
Heat Transport ◽  
Solar Power ◽  
Liquid Metals ◽  
Test System ◽  
Concentrated Solar Power ◽  
Power Cycles ◽  
Operation Temperature ◽  
Air Turbine ◽  
Temperature Heat

Liquid metals have received growing attention as a potential replacement for more conventional heat transfer fluids in concentrated solar power (CSP) systems. Owing to liquid metals high thermal conductivity, an increase in solar receiver efficiency as well as higher serviceable temperatures could enable more advanced power cycles to be integrated to the CSP system. Recently, CSIRO carried out research on a solar air turbine system which includes a demonstration of a high-temperature pressurized air receiver combined with high-temperature thermal storage. Since the operation temperature of a solar air turbine system is much higher than that of conventional CSP systems, Lead-Bismuth Eutectic (LBE) alloy was chosen for its favorable high temperature heat transport properties and relative ease of storage. The heat test apparatus consisted of a LBE-air heat exchanger, storage tanks with internal heating elements and a pumping system developed by CSIRO. During the test, approximately 1,000 kg of LBE was successfully pumped while capturing and storing approximately 35MJ of solar energy. The test successfully transferred heat from the solar air receiver to the LBE, with the temperature of stored LBE reaching over 770 °C. This paper will present the concept of the test system, design of its components, procedures and results of the test, and also lessons learnt.

scholarly journals Thermophysical properties experimentally tested for NaCl-KCl-MgCl2 eutectic molten salt as a next generation high temperature HTF in CSP systems

2020 ◽  
pp. 1-13
Author(s):  
Xiaoxin Wang ◽  
Jusus Rincon ◽  
Peiwen Li ◽  
Youyang Zhao ◽  
Judith Vidal
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Power Systems ◽  
Molten Salt ◽  
Thermophysical Properties ◽  
Power Plants ◽  
Solar Power ◽  
Thermal Power ◽  
Thermal Storage ◽  
Heat Of Fusion

Abstract A new eutectic chloride molten salt, MgCl2-KCl-NaCl (wt.% 45.98-38.91-15.11), has been recognized as one of the most promising high-temperature heat-transfer fluids (HTF) for both heat transfer and thermal storage for the 3rd Generation concentrated solar thermal power (CSP) systems. For the first time, some essential thermophysical properties of this eutectic chloride molten salt needed for basic heat transfer and energy storage analysis in the application of concentrating solar power systems have been experimentally tested and provided as functions of temperature in the range from 450 °C to 700 °C. The studied properties include heat capacity, melting point, heat of fusion, viscosity, vapor pressure, density, and thermal conductivity. The property equations provide essential database for engineers to use to calculate convective heat transfer in concentrated solar receivers, heat exchangers, and thermal storage for concentrated solar power plants.

High Temperature Thermochemical Heat Storage for Concentrated Solar Power Using Gas–Solid Reactions

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Franziska Schaube ◽  
Antje Wörner ◽  
Rainer Tamme
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Power Plants ◽  
Solar Power ◽  
Fixed Bed ◽  
Reaction System ◽  
Market Potential ◽  
Heat Of Reaction ◽  
Reactor Performance ◽  
Concentrated Solar Power

High temperature thermal storage technologies that can be easily integrated into future concentrated solar power plants are a key factor for increasing the market potential of solar power production. Storing thermal energy by reversible gas–solid reactions has the potential of achieving high storage densities while being adjustable to various plant configurations. In this paper the Ca(OH)2/CaO reaction system is investigated theoretically. It can achieve storage densities above 300 kWh/m3 while operating in a temperature range between 400 and 600°C. Reactor concepts with indirect and direct heat transfer are being evaluated. The low thermal conductivity of the fixed bed of solid reactants turned out to considerably limit the performance of a storage tank with indirect heat input through the reactor walls. A one-dimensional model for the storage reactor is established and solved with the Finite Element Method. The reactor concept with direct heat transfer by flowing the gaseous reactant plus additional inert gas through the solid reactants did not show any limitation due to heat transfer. If reaction kinetics are fast enough, the reactor performance in case of the Ca(OH)2/CaO reaction system is limited by the thermal capacity of the gaseous stream to take-up heat of reaction. However, to limit pressure drop and the according losses for compression of the gas stream, the size of the storage system is restricted in a fixed bed configuration.

scholarly journals Analysis of a Fluidized-Bed Particle/Supercritical-CO2 Heat Exchanger in a Concentrating Solar Power System

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Zhiwen Ma ◽  
Janna Martinek
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
High Efficiency ◽  
Solar Power ◽  
Concentrating Solar Power ◽  
Power Cycle ◽  
Temperature Heat ◽  
The Cost

Abstract Concentrating solar power (CSP) development has focused on increasing the energy conversion efficiency and lowering the capital cost. To improve performance, CSP research is moving to high-temperature and high-efficiency designs. One technology approach is to use inexpensive, high-temperature heat transfer fluids and storage, integrated with a high-efficiency power cycle such as the supercritical carbon dioxide (sCO2) Brayton power cycle. The sCO2 Brayton power cycle has strong potential to achieve performance targets of 50% thermal-to-electric efficiency and dry cooling at an ambient temperature of up to 40 °C and to reduce the cost of power generation. Solid particles have been proposed as a possible high-temperature heat transfer or storage medium that is inexpensive and stable at high temperatures above 1000 °C. The particle/sCO2 heat exchanger (HX) provides a connection between the particles and sCO2 fluid in emerging sCO2 power cycles. This article presents heat transfer modeling to analyze the particle/sCO2 HX design and assess design tradeoffs including the HX cost. The heat transfer process was modeled based on a particle/sCO2 counterflow configuration, and empirical heat transfer correlations for the fluidized bed and sCO2 were used to calculate heat transfer area and estimate the HX cost. A computational fluid dynamics simulation was applied to characterize particle distribution and fluidization. This article shows a path to achieve the cost and performance objectives for a particle/sCO2 HX design by using fluidized-bed technology.

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