scholarly journals Slag as an Inventory Material for Heat Storage in a Concentrated Solar Tower Power Plant: Design Studies and Systematic Comparative Assessment

2019 ◽  
Vol 9 (9) ◽  
pp. 1833 ◽  
Author(s):  
Michael Krüger ◽  
Jürgen Haunstetter ◽  
Philipp Knödler ◽  
Stefan Zunft

By using metallurgical slag from an electric arc furnace that is otherwise not recycled but deposited as an inventory material in thermal energy storage for concentrated solar power plants, it is possible to make a significant step forward in two transformation processes: energy and raw materials. As this type of slag has not been considered as an inventory material for this purpose, it is important to clarify fundamental questions about this low-cost material and its storage design. In this paper, design studies of slag-based thermal energy storage are carried out. Different slag-specific design concepts are developed, calculated and evaluated by a method based on established management tools. Finally, concepts for further investigations are defined. The highest aptitude value and the lowest risk value are achieved by the vertical storage design with axial flow direction. Therefore, it is taken as the lead concept and will be considered in complete detail in further research. Also, a closer look, but not as detailed as the lead concept, is taken at the horizontal storage with axial flow and the vertical storage with radial flow direction.

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4410
Author(s):  
Adio Miliozzi ◽  
Franco Dominici ◽  
Mauro Candelori ◽  
Elisabetta Veca ◽  
Raffaele Liberatore ◽  
...  

Thermal energy storage (TES) systems for concentrated solar power plants are essential for the convenience of renewable energy sources in terms of energy dispatchability, economical aspects and their larger use. TES systems based on the use of concrete have been demonstrated to possess good heat exchange characteristics, wide availability of the heat storage medium and low cost. Therefore, the purpose of this work was the development and characterization of a new concrete-based heat storage material containing a concrete mix capable of operating at medium–high temperatures with improved performance. In this work, a small amount of shape-stabilized phase change material (PCM) was included, thus developing a new material capable of storing energy both as sensible and latent heat. This material was therefore characterized thermally and mechanically and showed increased thermal properties such as stored energy density (up to +7%, with a temperature difference of 100 °C at an average operating temperature of 250 °C) when 5 wt% of PCM was added. By taking advantage of these characteristics, particularly the higher energy density, thermal energy storage systems that are more compact and economically feasible can be built to operate within a temperature range of approximately 150–350 °C with a reduction, compared to a concrete-only based thermal energy storage system, of approximately 7% for the required volume and cost.


2021 ◽  
pp. 1-40
Author(s):  
Zhiwen Ma ◽  
Xingchao Wang ◽  
Patrick Davenport ◽  
Jeffrey Gifford ◽  
Janna Martinek

Abstract Energy storage will become indispensable to complement the uncertainty of intermittent renewable resources and to firm the electricity supply as renewable power generation becomes the mainstream new-built energy source and fossil fuel power plants are phased out to meet carbon neutral utility targets. Current energy storage methods based on pumped storage hydropower or batteries have many limitations. Thermal energy storage (TES) has unique advantages in scale and siting flexibility to provide grid-scale storage capacity. A particle-based TES system is projected to have promising cost and performance characteristics to meet the future growing energy storage needs. This paper introduces the system and components required for particle TES to become technically and economically competitive. The system integrates electric particle heaters, particle TES within insulated concrete silos, and an efficient air-Brayton combined cycle power system to provide power for storage durations up to several days via low-cost, high-performance storage cycles. Design specifications and cost estimation of major components in a commercial-scale system are presented in this paper. A technoeconomic analysis based on preliminary component designs and performance indicates that particle TES integrated with an air-Brayton combined cycle power system has a path to achieve the targeted levelized cost of storage of 5¢/kWh-cycle at a round-trip efficiency of 50% when taking low-cost energy-specific components and leveraging basic assets from existing thermal power plants. The cost model provides insights for further development and economic potentials for long-duration energy storage.


2018 ◽  
Vol 40 (5) ◽  
pp. 560-575
Author(s):  
Jehanzeb Ahmad ◽  
M Najam Ul Islam ◽  
Jawwad Sabir

The benefits of thermal energy storage using phase change materials are well documented in the literature. Despite all the potential benefits of thermal energy storage, its commercial and widespread application remains limited. This is due to the high initial cost of phase change materials, extensive rework required in buildings, major modifications in HVAC systems, and the potential for leakage, fire and toxicity hazards. There is a strong need for a simple thermal energy storage solution which can be adopted by large number of consumers. Ductless split air-conditioners are portable, low cost, efficient and account for 70% of all air-conditioning systems sold worldwide each year. The present research provides a novel and low cost solution that incorporates thermal energy storage in these air conditioners, allowing them to run without electricity for 3 h. The paper deals with the detailed design aspects and engineering challenges that arise when incorporating thermal energy storage in these small units. A prototype air-conditioner with in-built thermal energy storage was developed, and all performance parameters presented have been validated through data obtained from the prototype. Our results indicate that thermal energy storage can be incorporated in split units in low cost and with minimal drop in overall energy efficiency of the system. Practical application: Incorporating thermal energy storage in split air-conditioners which enables them to run without grid for many hours has immense practical applications. Since around 50% power in any building is consumed by HVAC systems, being able to provide cooling during peak hours without using grid can significantly reduce load on the grid without compromising user comfort. For developing countries where load shedding is frequent, the users can run these air-conditioners without the use of generators or batteries thus saving costs and the environment.


2019 ◽  
Vol 21 ◽  
pp. 222-229 ◽  
Author(s):  
Lisa Boussaba ◽  
Said Makhlouf ◽  
Amina Foufa ◽  
Gilles Lefebvre ◽  
Laurent Royon

Author(s):  
Nicolas Calvet ◽  
Guilhem Dejean ◽  
Lucía Unamunzaga ◽  
Xavier Py

The ambitious DOE SunShot cost target ($0.06/kWh) for concentrated solar power (CSP) requires innovative concepts in the collector, receiver, and power cycle subsystems, as well as in thermal energy storage (TES). For the TES, one innovative approach is to recycle waste from metallurgic industry, called slags, as low-cost high-temperature thermal energy storage material. The slags are all the non-metallic parts of cast iron which naturally rises up by lower density at the surface of the fusion in the furnace. Once cooled down some ceramic can be obtained mainly composed of oxides of calcium, silicon, iron, and aluminum. These ceramics are widely available in USA, about 120 sites in 32 States and are sold at a very low average price of $5.37/ton. The US production of iron and steel slag was estimated at 19.7 million tons in 2003 which guarantees a huge availability of material. In this paper, electric arc furnace (EAF) slags from steelmaking industry, also called “black slags”, were characterized in the range of temperatures of concentrated solar power. The raw material is thermo-chemically stable up to 1100 °C and presents a low cost per unit thermal energy stored ($0.21/kWht for ΔT = 100 °C) and a suitable heat capacity per unit volume of material (63 kWht/m3for ΔT = 100°C). These properties should enable the development of new TES systems that could achieve the TES targets of the SunShot (temperature above 600 °C, installed cost below $15/kWht, and heat capacity ≥25 kWht/m3). The detailed experimental results are presented in the paper. After its characterization, the material has been shaped in form of plates and thermally cycled in a TES system using hot-air as heat transfer fluid. Several cycles of charge and discharged were performed successfully and the concept was validated at laboratory scale. Apart from availability, low-cost, and promising thermal properties, the use of slag promotes the conservation of natural resources and is a noble solution to decrease the cost and to develop sustainable TES systems.


2016 ◽  
Author(s):  
Mitchell Shinn ◽  
Karthik Nithyanandam ◽  
Amey Barde ◽  
Richard Wirz

Currently, concentrated solar power (CSP) plants utilize thermal energy storage (TES) in order to store excess energy so that it can later be dispatched during periods of intermittency or during times of high energy demand. Elemental sulfur is a promising candidate storage fluid for high temperature TES systems due to its high thermal mass, moderate vapor pressure, high thermal stability, and low cost. The objective of this paper is to investigate the behavior of encapsulated sulfur in a shell and tube configuration. An experimentally validated, transient, two-dimensional numerical model of the shell and tube TES system is presented. Initial results from both experimental and numerical analysis show high heat transfer performance of sulfur. The numerical model is then used to analyze the dynamic response of the elemental sulfur based TES system for multiple charging and discharging cycles. A sensitivity analysis is performed to analyze the effect of geometry (system length), cutoff temperature, and heat transfer fluid on the overall utilization of energy stored within this system. Overall, this paper demonstrates a systematic parametric study of a novel low cost, high performance TES system based on elemental sulfur as the storage fluid that can be utilized for different high temperature applications.


Author(s):  
Shahim Nisar

Abstract: Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation. TES systems are used particularly in buildings and in industrial processes. This paper is focused on TES technologies that provide a way of valorizing solar heat and reducing the energy demand of buildings. The principles of several energy storage methods and calculation of storage capacities are described. Sensible heat storage technologies, including water tank, underground and packed-bed storage methods, are briefly reviewed. Additionally, latent-heat storage systems associated with phase-change materials for use in solar heating/cooling of buildings, solar water heating, heat-pump systems, and concentrating solar power plants as well as thermo-chemical storage are discussed. Finally, cool thermal energy storage is also briefly reviewed and outstanding information on the performance and costs of TES systems are included.


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