scholarly journals Modeling, Simulation and Optimal Operation of Multi-Extraction Packed-Bed Thermal Storage Systems

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2247
Author(s):  
Alberto Romero ◽  
Ricardo Chacartegui ◽  
Emanuele Garone
Keyword(s):  
Storage Systems ◽  
Thermal Power ◽  
Thermal Storage ◽  
Packed Bed ◽  
Optimal Operation ◽  
Solar Irradiation ◽  
Heat Transfer Fluid ◽  
Thermodynamic Efficiency ◽  
Outlet Temperature ◽  
Control Approach

Solar thermal power technologies require storage systems to mitigate the natural variability of solar irradiation. Packed bed thermal storage systems (PBTES) offer a cost-effective solution using air as heat transfer fluid and rocks as a storage medium. Compared to its alternatives, however, PBTES presents a limited flexibility of operation due to the conventional unidirectional flow, which involves the progressive reduction of the outlet temperature during discharge and thus lowers the thermodynamic efficiency of the power cycle. The present study summarizes the progress on the design and optimal operation of a novel multi-extraction PBTES, a project that aims at mitigating its typically poor operational flexibility for solar power applications. To this end, a one-dimensional model with a high spatial resolution of a PBTES was developed, which includes four intermediate outlet points along the axial direction to investigate the benefits of optimal extraction operation. In order to reduce the computational burden, a coarser model of the storage system is used in combination with non-linear model predictive control (NLMPC). Through the optimal manipulation of the extraction valves, the output temperature is maintained close to a prescribed temperature throughout the discharge. The control admits not only constant temperature targets, but also time-varying scheduled profiles. This work describes the limitation of such a design and control approach and sets the direction for the future, more detailed analyses needed to demonstrate its applicability.

Experimental Investigation of Thermal Storage Processes in a Thermocline Storage Tank

2011 ◽  
Author(s):  
Wafaa Karaki ◽  
Peiwen Li ◽  
Jon Van Lew ◽  
M. M. Valmiki ◽  
Cholik Chan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Storage Tank ◽  
Power Plants ◽  
Thermal Power ◽  
Energy Charge ◽  
Thermal Storage ◽  
Packed Bed ◽  
Heat Transfer Fluid ◽  
Energy Storage Efficiency

This paper presents an experimental study and analysis of the heat transfer of energy charge and discharge in a packed-bed thermocline thermal storage tank for application in concentrated solar thermal power plants. Because the energy storage efficiency is a function of many parameters including fluid and solid properties, tank dimensions, packing dimensions, and time lengths of charge and discharge, this paper aims to provide experimental data and a proper approach of data reduction and presentation. To accomplish this goal, dimensionless governing equations of energy conservation in the heat transfer fluid and solid packed-bed material are derived. The obtained experimental data will provide a basis for validation of mathematical models in the future.

Longer Passage of Airflow in Multiple Packed-Bed Thin Tanks Versus in a Short Big Tank for Improved Thermal Storage Performance

2018 ◽  
Author(s):  
Yan Wang ◽  
Peiwen Li ◽  
Zhifeng Wang ◽  
Bei Yang ◽  
Guofeng Yuan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Storage System ◽  
Thermal Power ◽  
Thermal Storage ◽  
Packed Bed ◽  
Heat Transfer Fluid ◽  
Storage Efficiency ◽  
Storage Material ◽  
Solar Thermal Power ◽  
Storage Performance

A very challenging issue about solar thermal power generation is the use of a high temperature heat transfer fluid (water, oils, or molten salts) for heat transfer and thermal storage material, which may freeze at night or cold weather. When choosing air as the heat transfer fluid, the problem of freezing is eliminated. In order to increase the performance of thermal storage system which uses air as the heat transfer fluid passing through a packed bed (by ceramic spheres of Al2O3), multiple small-diameter tanks are considered to replace a single large-diameter tank with the same packed-bed volume and airflow rate in this paper. Analysis about the thermal storage performance in a short big tank and in cascade thin tanks has been made for comparison. A long passage of airflow and faster flow speed of air in the cascade thin tanks has been found significantly beneficial to thermal storage. Results about the increased thermal storage performance and increased pressure loss will be presented. Longer passage of airflow made it possible to have a longer time of high temperature of outflow air during discharging period. And faster speed of the fluid enhanced the heat transfer between air and thermal storage material. The total effective energy and thermal storage efficiency of cascade thin-tank thermal energy storage (TES) are higher. The thermal storage efficiency in the two types of thermal storage arrangement was compared for optimal design. The obtained results are of great significance to the development of using air as heat transfer fluid and rocks or ceramic spheres as the thermal storage material for thermal storage system in concentrated solar thermal power plants.

Thermal analysis and exergy evaluation of packed bed thermal storage systems

2013 ◽  
Vol 52 (2) ◽  
pp. 255-263 ◽  
Author(s):  
Hitesh Bindra ◽  
Pablo Bueno ◽  
Jeffrey F. Morris ◽  
Reuel Shinnar
Keyword(s):  
Thermal Analysis ◽  
Storage Systems ◽  
Thermal Storage ◽  
Packed Bed

scholarly journals Transient Heat Transfer and Energy Transport in Packed Bed Thermal Storage Systems

10.5772/20979 ◽  
2011 ◽  
Author(s):  
Pei Wen ◽  
Jon Van ◽  
Wafaa Karaki ◽  
Cho Lik ◽  
Jake Stephens ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Transport ◽  
Storage Systems ◽  
Thermal Storage ◽  
Packed Bed ◽  
Transient Heat Transfer

Packed bed thermal storage systems

1995 ◽  
Vol 51 (1) ◽  
pp. 51-67 ◽  
Author(s):  
T.M. Sanderson ◽  
G.T. Cunningham
Keyword(s):  
Storage Systems ◽  
Thermal Storage ◽  
Packed Bed

Investigation of a packed bed cold thermal storage in supercritical compressed air energy storage systems

2020 ◽  
Vol 269 ◽  
pp. 115132 ◽  
Author(s):  
Zhirong Liao ◽  
Hua Zhong ◽  
Chao Xu ◽  
Xing Ju ◽  
Feng Ye ◽  
...  
Keyword(s):  
Energy Storage ◽  
Storage Systems ◽  
Thermal Storage ◽  
Packed Bed ◽  
Compressed Air ◽  
Compressed Air Energy Storage ◽  
Energy Storage Systems

scholarly journals Optimal Operation Strategies into Deregulated Markets for 50 MWe Parabolic Trough Solar Thermal Power Plants with Thermal Storage

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 935 ◽  
Author(s):  
Jorge Llamas ◽  
David Bullejos ◽  
Manuel Ruiz de Adana
Keyword(s):  
Power Plant ◽  
Renewable Resources ◽  
Power Plants ◽  
Thermal Power ◽  
Thermal Storage ◽  
Optimal Operation ◽  
Solar Thermal ◽  
Thermal Power Plants ◽  
Parabolic Trough ◽  
Solar Thermal Power

The evolution of electric generation systems, according to relevant legislation, allows for the parallel evolution of the installed power capacity of renewable resources with the development of technologies for renewable resources, therefore optimizing the choice of energy mix from renewable resources by prioritizing the implementation of concentrating solar thermal plants. Thanks to their great potential, parabolic trough solar thermal power plants have become the most widely spread type of electricity generation by renewable solar energy. Nonetheless, the operation of the plant is not unique; it must be adapted to the parameters of solar radiation and market behavior for each specific location. This work focuses on the search for the optimal strategies of operation by a mathematical model of a 50 MWe parabolic trough thermal power plant with thermal storage. The analysis of the different ways of operation throughout a whole year, including model verification via a currently operating plant, provides meaningful insights into the electricity generated. Focused to work under non-regulated electricity markets to adjust this type of technology to the European directives, the presented model of optimization allows for the adaptation of the curve of generation to the network demands and market prices, rising the profitability of the power plant. Thus, related to solar resources and market price, the economic benefit derived from the electricity production improves between 5.17% and 7.79%.

scholarly journals High-Temperature Chloride-Carbonate Phase Change Material: Thermal Performances and Modelling of a Packed Bed Storage System for Concentrating Solar Power Plants

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5339
Author(s):  
Giovanni Salvatore Sau ◽  
Valerio Tripi ◽  
Anna Chiara Tizzoni ◽  
Raffaele Liberatore ◽  
Emiliana Mansi ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Phase Change ◽  
Power Plants ◽  
Solar Power ◽  
Storage System ◽  
Ternary Eutectic ◽  
Thermal Storage ◽  
Packed Bed ◽  
Heat Transfer Fluid

Molten salts eutectics are promising candidates as phase change materials (PCMs) for thermal storage applications, especially considering the possibility to store and release heat at high temperatures. Although many compounds have been proposed for this purpose in the scientific literature, very few data are available regarding actual applications. In particular, there is a lack of information concerning thermal storage at temperatures around 600 °C, necessary for the coupling with a highly efficient Rankine cycle powered by concentrated solar power (CSP) plants. In this contest, the present work deals with a thermophysical behavior investigation of a storage heat exchanger containing a cost-effective and safe ternary eutectic, consisting of sodium chloride, potassium chloride, and sodium carbonate. This material was preliminarily and properly selected and characterized to comply with the necessary melting temperature and latent enthalpy. Then, an indirect heat exchanger was considered for the simulation, assuming aluminum capsules to confine the PCM, thus obtaining the maximum possible heat exchange surface and air at 5 bar as heat transfer fluid (HTF). The modelling was carried out setting the inlet and outlet air temperatures at, respectively, 290 °C and 550 °C, obtaining a realistic storage efficiency of around 0.6. Finally, a conservative investment cost was estimated for the storage system, demonstrating a real possible economic benefit in using these types of materials and heat exchange geometries, with the results varying, according to possible manufacturing prices, in a range from 25 to 40 EUR/kWh.

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