scholarly journals Considerations for the Design of a High-Temperature Particle Reoxidation Reactor for Extraction of Heat in Thermochemical Energy Storage Systems

2016 ◽  
Author(s):  
Sean M. Babiniec ◽  
James E. Miller ◽  
Andrea Ambrosini ◽  
Ellen Stechel ◽  
Eric N. Coker ◽  
...  
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Molten Salts ◽  
Coupled System ◽  
Thermal Reduction ◽  
Solid Particles ◽  
Working Fluid ◽  
Reactor Outlet ◽  
Transfer Rates ◽  
Storage Media

In an effort to increase thermal energy storage densities and turbine inlet temperatures in concentrating solar power (CSP) systems, focus on energy storage media has shifted from molten salts to solid particles. These solid particles are stable at temperatures far greater than that of molten salts, allowing the use of efficient high-temperature turbines in the power cycle. Furthermore, many of the solid particles under development store heat via reversible chemical reactions (thermochemical energy storage, TCES) in addition to the heat they store as sensible energy. The heat-storing reaction is often the thermal reduction of a metal oxide. If coupled to an Air-Brayton system, wherein air is used as the turbine working fluid, the subsequent extraction of both reaction and sensible heat, as well as the transfer of heat to the working fluid, can be accomplished in a direct-contact, counter-flow reoxidation reactor. However, there are several design challenges unique to such a reactor, such as maintaining requisite residence times for reactions to occur, particle conveying and mitigation of entrainment, and the balance of kinetics and heat transfer rates to achieve reactor outlet temperatures in excess of 1200 °C. In this paper, insights to addressing these challenges are offered, and design and operational tradeoffs that arise in this highly-coupled system are introduced and discussed.

High-temperature molten salts optimisation using mixture design for energy storage application

2020 ◽  
Vol 32 ◽  
pp. 101981
Author(s):  
Mahesh Vaka ◽  
Rashmi Walvekar ◽  
Priyanka Jagadish ◽  
Mohammad Khalid ◽  
Nabisab Mujawar Mubarak ◽  
...  
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Molten Salts ◽  
Mixture Design ◽  
Energy Storage Application

scholarly journals Thermodynamic Performance of a Brayton Pumped Heat Energy Storage System: Influence of Internal and External Irreversibilities

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1564
Author(s):  
David Pérez-Gallego ◽  
Julian Gonzalez-Ayala ◽  
Antonio Calvo Hernández ◽  
Alejandro Medina
Keyword(s):  
Energy Storage ◽  
Storage System ◽  
Heat Engine ◽  
Coupled System ◽  
Packed Bed ◽  
Physical Region ◽  
Energy Storage System ◽  
Working Fluid ◽  
Round Trip ◽  
Output Efficiency

A model for a pumped thermal energy storage system is presented. It is based on a Brayton cycle working successively as a heat pump and a heat engine. All the main irreversibility sources expected in real plants are considered: external losses arising from the heat transfer between the working fluid and the thermal reservoirs, internal losses coming from pressure decays, and losses in the turbomachinery. Temperatures considered for the numerical analysis are adequate for solid thermal reservoirs, such as a packed bed. Special emphasis is paid to the combination of parameters and variables that lead to physically acceptable configurations. Maximum values of efficiencies, including round-trip efficiency, are obtained and analyzed, and optimal design intervals are provided. Round-trip efficiencies of around 0.4, or even larger, are predicted. The analysis indicates that the physical region, where the coupled system can operate, strongly depends on the irreversibility parameters. In this way, maximum values of power output, efficiency, round-trip efficiency, and pumped heat might lay outside the physical region. In that case, the upper values are considered. The sensitivity analysis of these maxima shows that changes in the expander/turbine and the efficiencies of the compressors affect the most with respect to a selected design point. In the case of the expander, these drops are mostly due to a decrease in the area of the physical operation region.

Investigation of Sr-based perovskites for redox-type thermochemical energy storage media at medium-high temperature

2021 ◽  
Vol 38 ◽  
pp. 102501
Author(s):  
Xiaoyu Chen ◽  
Mitsuhiro Kubota ◽  
Seiji Yamashita ◽  
Hideki Kita
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Storage Media

The DIAPR: A High-Pressure, High-Temperature Solar Receiver

1997 ◽  
Vol 119 (1) ◽  
pp. 74-78 ◽  
Author(s):  
J. Karni ◽  
A. Kribus ◽  
P. Doron ◽  
R. Rubin ◽  
A. Fiterman ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Performance ◽  
Fused Silica ◽  
Solid Particles ◽  
Working Fluid ◽  
Thermochemical Process ◽  
Working Medium ◽  
Main Components ◽  
Solar Receiver

A solar central receiver absorbs concentrated sunlight and transfers its energy to a working medium (gas, liquid or solid particles), either in a thermal or a thermochemical process. Various attractive high-performance applications require the solar receiver to supply the working fluid at high temperature (900–1500°C) and high pressure (10–35 bar). As the inner receiver temperature may be well over 1000°C, sunlight concentration at its aperture must be high (4–8 MW/m2), to minimize aperture size and reradiation losses. The Directly Irradiated Annular Pressurized Receiver (DIAPR) is a volumetric (directly irradiated), windowed cavity receiver that operates at aperture flux of up to 10 MW/m2. It is capable of supplying hot gas at a pressure of 10–30 bar and exit temperature of up to 1300°C. The three main innovative components of this receiver are: • a Porcupine absorber, made of a high-temperature ceramic (e.g., alumina); • a Frustum-Like High-Pressure (FLHIP) window, made of fused silica; • a two-stage secondary concentrator followed by the KohinOr light extractor. This paper presents the design principles of the DIAPR, its structure and main components, and examples of experimental and computational results.

Investigation of High Temperature Nanofluids for Solar Thermal Power Conversion and Storage Applications

2010 ◽  
Author(s):  
Donghyun Shin ◽  
Byeongnam Jo ◽  
Hyun-eun Kwak ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Capacity ◽  
Thermal Properties ◽  
High Temperature ◽  
Energy Storage ◽  
Physical Properties ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Molten Salts ◽  
Solar Thermal ◽  
Thermo Physical Properties

The aim of this study is to investigate the enhancement of thermal properties of various high temperature nanofluids for solar thermal energy storage application. In concentrating solar power (CSP) systems, the thermo-physical properties of the heat transfer fluids (HTF) and the thermal energy storage (TES) materials are key to enhancing the overall system efficiency. Molten salts, such as alkali nitrates, alkali carbonates, or eutectics are considered as alternatives to conventional HTF to extend the capabilities of CSP. However, there is limited usage of molten salt eutectics as the HTF material, since the heat capacity of the molten salts are lower than that of conventional HTF. Nanofluid is a mixture of a solvent and nanoparticles. Well dispersed nanoparticles can be used to enhance thermo-physical properties of HTF. In this study, silica (SiO2) and alumina (Al2O3) nanoparticles as well as carbon nanotubes (CNT) were dispersed into a molten salt and a commercially available HTF. The specific heat capacity of the nanofluids were measured and applicability of such nanofluid materials for solar thermal storage applications were explored. Measurements performed using the carbonate eutectics and commercial HTF that are doped with inorganic and organic nano-particles show specific heat capacity enhancements exceeding 5–20% at concentrations of 0.05% to 2.0% by weight. Dimensional analyses and computer simulations were performed to predict the enhancement of thermal properties of the nanofluids. The computational studies were performed using Molecular Dynamics (MD) simulations.

Parametric Study of High-Temperature Thermochemical Energy Storage Using Manganese-Iron Oxide

2019 ◽  
Author(s):  
Nasser Vahedi ◽  
Alparslan Oztekin
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Energy Density ◽  
Metal Oxides ◽  
Manganese Oxide ◽  
Working Fluid ◽  
Enthalpy Of Reaction ◽  
Iron Doped ◽  
Continuous Power ◽  
New Generation

Abstract Continuous power supply in Concentrated Solar Power (CSP) plants can be achieved via integration of efficient, cost-effective and reliable Thermal Energy Storage (TES) system. The new generation of CSPs operates at higher temperatures and requires thermal storage systems with higher energy density at high storage temperature. Thermochemical Energy Storage (TCES) is the available solution which can meet performance requirements of energy density, temperature, and stability. TCES systems apply reversible endothermic/exothermic chemical reaction through which energy is stored as the enthalpy of reaction and released during the reverse mode. Among several available potential reversible chemical reactions, metal oxides, with high reaction temperature and enthalpy of reaction, have remarkable advantages compared to others. They use air both as Heat Transfer Fluid (HTF) and oxidation reactant, which eliminates the need for storage and intermediate heat exchanger integration between HTF and collector working fluid. Using air as HTF has made them perfectly fitted for the new generation of air operated solar collectors. Among several screened available potential metal oxides, cobalt and manganese oxides were selected as best candidates for high-temperature storage. Pure manganese oxide does not meet the cyclic operation requirement, but the iron-doped solid solution has proven reasonable cyclic storage performance. In this study, iron-doped manganese oxide (Fe-Mn 1:3 molar ratio) has been selected as a redox agent for TCES reactor. The cylindrical packed bed configuration is considered as a reactor bed configuration. A two-dimensional axisymmetric numerical model is developed using the finite element method. Performance analysis for both charge and discharge is provided separately. The effect of inflow rate and bed porosity variations on reactor performance in complete storage cycle were studied.

scholarly journals Compatibility tests between high temperature concrete and molten salts to be used for a thermal energy storage

2019 ◽  
Author(s):  
F. Felizardo ◽  
L. Guerreiro ◽  
M. Roig-Flores ◽  
M. C. Alonso ◽  
M. Collares-Pereira
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Molten Salts

Parametric Study on the Operating Efficiencies of a Packed Bed for High-Temperature Sensible Heat Storage

1998 ◽  
Vol 120 (1) ◽  
pp. 2-13 ◽  
Author(s):  
G. A. Adebiyi ◽  
E. C. Nsofor ◽  
W. G. Steele ◽  
A. A. Jalalzadeh-Azar
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Heat Storage ◽  
Storage System ◽  
Packed Bed ◽  
Second Law ◽  
Operating Parameters ◽  
Sensible Heat ◽  
Storage Media ◽  
Transient Conduction

A comprehensive computer model of a packed bed thermal energy storage system originally developed for storage media employing either sensible heat storage (SHS) materials or phase-change material (PCM), was validated for the sensible heat storage media using a rather extensive set of data obtained with a custom-made experimental facility for high-temperature energy storage. The model is for high-temperature storage and incorporates several features including (a) allowance for media property variations with temperature, (b) provisions for arbitrary initial conditions and time-dependent varying fluid inlet temperature to be set, (c) formulation for axial thermal dispersion effects in the bed, (d) modeling for intraparticle transient conduction in the storage medium, (e) provision for energy storage (or accumulation) in the fluid medium, (f) modeling for the transient conduction in the containment vessel wall, (g) energy recovery in two modes, one with flow direction parallel with that in the storage mode (cocurrent) and the other with flow in the opposite direction (countercurrent), and (h) computation of the first and second-law efficiencies. Parametric studies on the sensible heat storage system were carried out using the validated model to determine the effects of several of the design and operating parameters on the first and second-law efficiencies of the packed bed. Decisions on the thermodynamic optimum system design and operating parameters for the packed bed are based on the second-law evaluations made

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