Advanced Thermal Energy Storage Technology for Parabolic Trough

Author(s):  
Rainer Tamme ◽  
Doerte Laing ◽  
Wolf-Dieter Steinmann

The availability of storage capacity plays an important role for the economic success of solar thermal power plants. For today’s parabolic trough power plants, sensible heat storage systems with operation temperatures between 300°C and 390°C can be used. A solid media sensible heat storage system is developed and will be tested in a parabolic trough test loop at PSA, Spain. A simulation tool for the analysis of the transient performance of solid media sensible heat storage systems has been implemented. The computed results show the influence of various parameters describing the storage system. While the effects of the storage material properties are limited, the selected geometry of the storage system is important. The evaluation of a storage system demands the analysis of the complete power plant and not only of the storage unit. Then the capacity of the system is defined by the electric work produced by the power plant, during a discharge process of the storage unit. The choice of the operation strategy for the storage system proves to be essential for the economic optimization.

2004 ◽  
Vol 126 (2) ◽  
pp. 794-800 ◽  
Author(s):  
Rainer Tamme ◽  
Doerte Laing ◽  
Wolf-Dieter Steinmann

The availability of storage capacity plays an important role for the economic success of solar thermal power plants. For today’s parabolic trough power plants, sensible heat storage systems with operation temperatures between 300°C and 390°C can be used. A solid media sensible heat storage system is developed and will be tested in a parabolic trough test loop at PSA, Spain. A simulation tool for the analysis of the transient performance of solid media sensible heat storage systems has been implemented. The computed results show the influence of various parameters describing the storage system. While the effects of the storage material properties are limited, the selected geometry of the storage system is important. The evaluation of a storage system demands the analysis of the complete power plant and not only of the storage unit. Then the capacity of the system is defined by the electric work produced by the power plant during a discharge process of the storage unit. The choice of the operation strategy for the storage system proves to be essential for the economic optimization.


2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Doerte Laing ◽  
Wolf-Dieter Steinmann ◽  
Michael Fiß ◽  
Rainer Tamme ◽  
Thomas Brand ◽  
...  

Cost-effective integrated storage systems are important components for the accelerated market penetration of solarthermal power plants. Besides extended utilization of the power block, the main benefits of storage systems are improved efficiency of components, and facilitated integration into the electrical grids. For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option in terms of investment and maintenance costs. For commercial oil trough technology, a solid media sensible heat storage system was developed and tested. One focus of the project was the cost reduction of the heat exchanger; the second focus lies in the energetic and exergetic analysis of modular storage operation concepts, including a cost assessment of these concepts. The results show that technically there are various interesting ways to improve storage performance. However, these efforts do not improve the economical aspect. Therefore, the tube register with straight parallel tubes without additional structures to enhance heat transfer has been identified as the best option concerning manufacturing aspects and investment costs. The results of the energetic and exergetic analysis of modular storage integration and operation concepts show a significant potential for economic optimization. An increase of more than 100% in storage capacity or a reduction of more than a factor of 2 in storage size and therefore investment cost for the storage system was calculated. A complete economical analysis, including the additional costs for this concept on the solar field piping and control, still has to be performed.


2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Doerte Laing ◽  
Thomas Bauer ◽  
Dorothea Lehmann ◽  
Carsten Bahl

For future parabolic trough plants direct steam generation in the absorber pipes is a promising option for reducing the costs of solar thermal power generation. These new solar thermal power plants require innovative storage concepts, where the two-phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e., for preheating of water and superheating of steam. A pinch analysis helps to recognize interface constraints imposed by the solar field and the power block and describes a way to dimension the latent and sensible components. Laboratory test results of a PCM test module with ∼140 kgNaNO3, applying the sandwich concept for enhancement of heat transfer, are presented, proving the expected capacity and power density. The concrete storage material for sensible heat was improved to allow the operation up to 500°C for direct steam generation. A storage system with a total storage capacity of ∼1 MWh is described, combining a PCM module and a concrete module, which will be tested in 2009 under real steam conditions around 100 bars.


Author(s):  
Jan Fabian Feldhoff ◽  
Kai Schmitz ◽  
Markus Eck ◽  
Lars Schnatbaum-Laumann ◽  
Doerte Laing ◽  
...  

Parabolic trough power plants are currently the most commercially applied systems for CSP power generation. To improve their cost-effectiveness, one focus of industry and research is the development of processes with other heat transfer fluids than the currently used synthetic oil. One option is the utilization of water/steam in the solar field, the so-called direct steam generation (DSG). Several previous studies promoted the economic potential of DSG technology [1–3]. Analyses’ results showed that live steam parameters of up to 500°C and 120 bars are most promising and could lead to a reduction of the levelized electricity cost (LEC) of about 11% [4]. However, all of these studies only considered plants without thermal energy storage (TES). Therefore, a system analysis including integrated TES was performed by Flagsol GmbH and DLR together with Solar Millennium AG, Schott CSP GmbH and Senior Bergho¨fer GmbH, all Germany. Two types of plants are analyzed and compared in detail: a power plant with synthetic oil and a DSG power plant. The design of the synthetic oil plant is very similar to the Spanish Andasol plants [5] and includes a molten salt two-tank storage system. The DSG plant has main steam parameters of 500 °C and 112 bars and uses phase change material (PCM) for the latent and molten salt for the sensible part of the TES system. To enable comparability, both plants share the same gross electric turbine capacity of 100 MWel, the same TES capacity of nine hours of full load equivalent and the same solar multiple of the collector field of about two. This paper describes and compares both plants’ design, performance and investment. Based on these results, the LEC are calculated and the DSG plant’s potential is evaluated. One key finding is that with currently proposed DSG storage costs, the LEC of a DSG plant could be higher than those of a synthetic oil plant. When considering a plant without TES on the other hand, the DSG system could reduce the LEC. This underlines the large influence of TES and the still needed effort in the development of a commercial storage system for DSG.


2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Wolf-Dieter Steinmann ◽  
Rainer Tamme

Solar thermal systems, including direct steam generation in the absorbers, require isothermal energy storage systems. One option to fulfil this requirement is the application of phase change materials (PCMs) to absorb or release energy. The implementation of cost-effective storage systems demands the compensation of the low thermal heat conductivity that is characteristic for the candidate materials for PCM. Solar steam generation for power plants requires latent heat storage systems for a saturation temperature range between 200°C and 320°C. This paper describes the basic concepts investigated and first results of research activities aiming at the demonstration of a storage system using steam provided by parabolic trough collectors.


Author(s):  
Doerte Laing ◽  
Thomas Bauer ◽  
Dorothea Lehmann ◽  
Carsten Bahl

For future parabolic trough plants direct steam generation in the absorber pipes is a promising option for reducing the costs of solar thermal power generation. These new solar thermal power plants require innovative storage concepts, where the two phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e. for preheating of water and superheating of steam. A pinch analysis helps to recognize interface constraints imposed by the solar field and the power block and describes a way to dimension the latent and sensible components. Laboratory test results of a PCM test module with approx. 140 kg NaNO3, applying the sandwich concept for enhancement of heat transfer, are presented, proving the expected capacity and power density. The concrete storage material for sensible heat was improved to allow the operation up to 500 °C for direct steam generation. A storage system with a total storage capacity of approx. 1 MWh is described, combining a PCM module and a concrete module, which will be tested in 2009 under real steam conditions around 100 bar.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4940
Author(s):  
Michela Lanchi ◽  
Luca Turchetti ◽  
Salvatore Sau ◽  
Raffaele Liberatore ◽  
Stefano Cerbelli ◽  
...  

One of the most interesting perspectives for the development of concentrated solar power (CSP) is the storage of solar energy on a seasonal basis, intending to exploit the summer solar radiation in excess and use it in the winter months, thus stabilizing the yearly production and increasing the capacity factor of the plant. By using materials subject to reversible chemical reactions, and thus storing the thermal energy in the form of chemical energy, thermochemical storage systems can potentially serve to this purpose. The present work focuses on the identification of possible integration solutions between CSP plants and thermochemical systems for long-term energy storage, particularly for high-temperature systems such as central receiver plants. The analysis is restricted to storage systems potentially compatible with temperatures ranging from 700 to 1000 °C and using gases as heat transfer fluids. On the basis of the solar plant specifications, suitable reactive systems are identified and the process interfaces for the integration of solar plant/storage system/power block are discussed. The main operating conditions of the storage unit are defined for each considered case through process simulation.


2020 ◽  
Vol 205 ◽  
pp. 07013
Author(s):  
Henok Hailemariam ◽  
Frank Wuttke

This paper focuses on the experimental investigation of the transient thermo-mechanical behavior of a lab-scale prototype heat storage system. The experiment involves heating of the storage unit up to a set temperature of 70°C followed by a passive cooling, and monitoring the thermally induced strains and stresses in the sensible heat storage module. The results show a significant development of induced thermal strains and stresses in the heat storage unit upon heating, particularly at the interface between the embedded heating element and the soil.


2010 ◽  
Vol 132 (4) ◽  
Author(s):  
D. Laing ◽  
W. D. Steinmann ◽  
P. Viebahn ◽  
F. Gräter ◽  
C. Bahl

For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option in terms of investment and maintenance costs. One important aspect in storage development is the storage integration into the power plant. A modular operation concept for thermal storage systems was previously suggested by DLR, showing an increase in storage capacity of more than 100%. However, in these investigations, the additional costs needed to implement this storage concept into the power plant, such as for extra piping, valves, pumps, and control, had not been considered. These aspects are discussed in this paper, showing a decrease in levelized energy costs with a modular storage integration of 2–3%. In a life cycle assessment a comparison of an AndaSol-I type solar thermal power plant with the original two-tank molten salt storage and with a “hypothetical” concrete storage shows an advantage of the concrete storage technology concerning environmental impacts. The environmental impacts of the hypothetical concrete based AndaSol-I decreased by 7%, considering 1 kW h of solar electricity delivered to the grid. Regarding only the production of the power plant, the emissions decreased by 9.5%.


Author(s):  
Evgeniy Chupin ◽  
Konstantin Frolov ◽  
Maxim Korzhavin ◽  
Oleg Zhdaneev

AbstractEnergy storage systems are an important component of the energy transition, which is currently planned and launched in most of the developed and developing countries. The article outlines development of an electric energy storage system for drilling based on electric-chemical generators. Description and generalization are given for the main objectives for this system when used on drilling rigs isolated within a single pad, whether these are fed from diesel gensets, gas piston power plants, or 6–10 kV HV lines. The article studies power operating modes of drilling rigs, provides general conclusions and detailed results for one of more than fifty pads. Based on the research, a generic architecture of the energy storage module is developed, and an engineering prototype is built. The efficiency of using a hybrid energy accumulation design is proven; the design calls for joint use of Li-ion cells and supercapacitors, as well as three-level inverters, to control the storage system. The article reviews all possible options for connecting the system into a unified rig power circuit, and the optimum solution is substantiated. The research into the rig operating modes and engineering tests yielded a simplified mathematical model of an energy storage unit integrated into the power circuit of a drilling rig. The model is used to forecast the payoff period of the system for various utilization options and rig operating modes. The findings of this study can help to better understand which type of storage system is the most efficient for energy systems with temporary high load peaks, like drilling rigs.


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