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.

Volume Sizing for Thermal Storage With Phase Change Material for Concentrated Solar Power Plant

2014 ◽  
Author(s):  
Ben Xu ◽  
Peiwen Li ◽  
Cholik Chan
Keyword(s):  
Power Plant ◽  
Phase Change ◽  
Phase Change Material ◽  
Storage Tank ◽  
Solar Power ◽  
Heat Storage ◽  
Storage System ◽  
Thermal Storage ◽  
Concentrated Solar Power ◽  
Change Material

With a large capacity thermal storage system using phase change material (PCM), Concentrated Solar Power (CSP) is a promising technology for high efficiency of solar energy utilization. In a thermal storage system, a dual-media thermal storage tank is typically adopted in industry for the purpose of reducing the use of the heat transfer fluid (HTF). While the dual-media sensible heat storage system has been well studied, a dual-media latent heat storage system (LHSS) still needs more attention and study; particularly, the sizing of volumes of storage tanks considering actual operation conditions is of significance. In this paper, a strategy for LHSS volume sizing is proposed, which is based on computations using an enthalpy-based 1D model. One example of 60MW solar thermal power plant with 35% thermal efficiency is presented. In the study, potassium hydroxide (KOH) is adopted as PCM and Therminol VP-1 is used as HTF. The operational temperatures of the storage system are 390°C and 310°C, respectively for the high and low temperatures. The system is assumed to operate for 100 days with 6 hours charge and 6 hours discharge every day. From the study, the needed height of the thermal storage tank is calculated from using the strategy of tank sizing. The method for tank volume sizing is of significance to engineering application.

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.

Analysis of New Heat Exchanger Performance in Phase Change Energy Storage

2014 ◽  
Vol 1061-1062 ◽  
pp. 638-644 ◽  
Author(s):  
Yu Qiu ◽  
Xi Luo ◽  
Qiong Fen Yu ◽  
Yong Feng Xu ◽  
Cong Bin Leng ◽  
...  
Keyword(s):  
Heat Flux ◽  
Heat Exchanger ◽  
Phase Change ◽  
Thermal Storage ◽  
Heat Transfer Fluid ◽  
Melting Time ◽  
Heating Wall ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Shell And Tube

Based on traditional shell-and-tubeheat exchanger, a new heat exchanger which applies to phase change thermal storage was proposed. The thermal storage process of new heat exchanger and shell-and-tube heat exchanger which use paraffin as phase change material and use water as heat-transfer fluid can be simulated by CFD software, respectively. The changes of liquid fraction and heat flux density along with time have been got by computer stimulation. It can be found that maximum heat flux of the new heat exchanger heating wall is 2.5 times than shell-and-tube heat exchanger, melting time of the new heat exchanger is 5 times than shell-and-tube heat exchanger. From the two aspects, the heat storage effect of new heat exchanger is better than conventional concentric tube heat exchanger.

The Benefit of Using Multiple Thin Tanks Versus a Short Big Tank for Thermal Storage in Ceramic-Sphere Packed Bed With Airflow

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Yan Wang ◽  
Peiwen Li ◽  
Zhifeng Wang ◽  
Bei Yang ◽  
Guofeng Yuan
Keyword(s):  
Heat Transfer ◽  
Storage System ◽  
Large Diameter ◽  
Small Diameter ◽  
Operation Time ◽  
Thermal Storage ◽  
Packed Bed ◽  
Heat Transfer Fluid ◽  
Optimization Methodology ◽  
Energy Storage Efficiency

Abstract To make a better thermal storage system that uses air as the heat transfer fluid flowing through a packed-bed of ceramic spheres (Al2O3) as thermal storage materials, the present work studied cases using multiple small-diameter thin tanks to replace a large-diameter big tank while keeping the same total volume and the same air flow rate. Performance analysis of thermal storage has been conducted for comparison and optimization. The long flow passage and faster flow velocity of air in the small-diameter tanks was found to significantly benefit thermal storage performance compared with that of a short big tank. It resulted in a longer duration of discharge of high-temperature airflow, if the same operation time is applied to the two situations. The faster airflow enhances the heat transfer between air and thermal storage material, although it incurs larger pressure loss. Overall, the energy storage efficiency of using several thin tanks can be significantly better than that of using a big short tank if the height-to-diameter ratio in the multiple thin tanks is properly optimized. The optimization methodology and results are of great significance to the development of thermal storage systems that use air as heat transfer fluid and rocks or ceramic spheres as the packed-bed material for thermal storage.

Development of a Molten-Salt Thermocline Thermal Storage System for Parabolic Trough Plants

2002 ◽  
Vol 124 (2) ◽  
pp. 153-159 ◽  
Author(s):  
James E. Pacheco ◽  
Steven K. Showalter ◽  
William J. Kolb
Keyword(s):  
Molten Salt ◽  
Thermal Gradient ◽  
Power Plants ◽  
Low Cost ◽  
Storage System ◽  
Thermal Storage ◽  
Pilot Scale ◽  
Heat Transfer Fluid ◽  
Parabolic Trough ◽  
Molten Salt System

Thermal storage improves the dispatchability and marketability of parabolic trough power plants allowing them to produce electricity on demand independent of solar collection. One such thermal storage system, a thermocline, uses a single tank containing a fluid with a thermal gradient running vertically through the tank, where hotter fluid (lower density) is at the top of the tank and colder fluid is at the base of the tank. The thermal gradient separates the two temperature potentials. A low-cost filler material provides the bulk of the thermal capacitance of the thermal storage, prevents convective mixing, and reduces the amount of fluid required. In this paper, development of a thermocline system that uses molten-nitrate salt as the heat transfer fluid is described and compared to a two-tank molten salt system. Results of isothermal and thermal cycling tests on candidate materials and salt safety tests are presented as well as results from a small pilot-scale (2.3 MWh) thermocline.

scholarly journals Waste heat recovery from diesel engine using custom designed heat exchanger and thermal storage system with nanoenhanced phase change material

2017 ◽  
Vol 21 (1 Part B) ◽  
pp. 715-727 ◽  
Author(s):  
John Wilson ◽  
Abhishek Singh ◽  
Abhinay Singh ◽  
Subramanian Ganapathy
Keyword(s):  
Heat Exchanger ◽  
Diesel Engine ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Recovery ◽  
Storage System ◽  
Thermal Storage ◽  
Heat Energy ◽  
Heat Extraction ◽  
Change Material

In this research study an attempt has been made to recover the heat energy of the exhaust gas from a Diesel engine, using a triangular finned shell and tube heat exchanger with segmental baffle at 20?, and efficiently store as sensible and latent heat energy using thermal storage tank having phase change material with CuO nanoparticles. The nanoparticles and the phase change material form the nanoparticle-enhanced phase change material and mainly the thermal conductivity of the phase change material can be enhanced through the dispersion of the nanoparticles. The temperature variations of the heat transfer fluid in the heat recovery heat exchanger with various load conditions of the Diesel engine are studied. The performance of the heat exchanger is evaluated using heat extraction rate and effectiveness. Evaluation of the performance of the thermal storage system can be analyzed by using the total heat energy stored and charging rate during the charging period for the selected nanoparticle-enhanced phase change material.

Design and Analysis of Low-Cost Thermal Storage System for High Efficiency Concentrating Solar Power Plants

2016 ◽  
Author(s):  
Karthik Nithyanandam ◽  
Amey Barde ◽  
Reza Baghaei Lakeh ◽  
Richard Wirz
Keyword(s):  
High Temperatures ◽  
Power Plants ◽  
Solar Power ◽  
Storage System ◽  
Cost Effective ◽  
Thermal Storage ◽  
System Level ◽  
Complex Conjugate ◽  
Concentrating Solar Power ◽  
Solar Power Plants

The ability to efficiently and cost-effectively incorporate thermal energy storage (TES) systems is an important advantage of concentrating solar power (CSP) in comparison to other intermittent forms of renewable energy, such as wind or photovoltaics. As such, TES allows CSP plants to continue to provide electricity to the grid even at times when the resource (the sun) is not available, such as cloud transients or at night. Advanced power cycle systems with supercritical carbon dioxide (sCO2) as the working fluid provide high power conversion efficiency because of high temperatures attained, and less compression work and are being explored for integration with concentrating solar power plants. Currently, there is no cost-effective way to store energy at high temperatures (>565 degree Celsius). The present work analyzes the thermal performance of a novel, cost-effective thermal storage system based on elemental sulfur as the storage media. The analysis is based on a detailed system-level computational modeling of the complex conjugate heat transfer and fluid flow phenomena at multiple scales to provide a scientific basis for engineering, designing and optimizing the novel thermal storage system for transient operation. The validation of the computational model based on data from experiments and full-scale plant operation is also reported. Our studies have shown sulfur-based TES to be a promising candidate for high temperature CSP.

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