Solid media thermal storage for parabolic trough power plants

Solar Energy ◽  
2006 ◽  
Vol 80 (10) ◽  
pp. 1283-1289 ◽  
Author(s):  
Doerte Laing ◽  
Wolf-Dieter Steinmann ◽  
Rainer Tamme ◽  
Christoph Richter
Keyword(s):  
Power Plants ◽  
Thermal Storage ◽  
Parabolic Trough ◽  
Solid Media

Solid Media Thermal Storage Development and Analysis of Modular Storage Operation Concepts for Parabolic Trough Power Plants

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Doerte Laing ◽  
Wolf-Dieter Steinmann ◽  
Michael Fiß ◽  
Rainer Tamme ◽  
Thomas Brand ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Heat Storage ◽  
Storage Systems ◽  
Storage System ◽  
Sensible Heat ◽  
Economic Optimization ◽  
Parabolic Trough ◽  
Solid Media ◽  
Exergetic Analysis

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.

scholarly journals Conceptual Study of a Thermal Storage Module for Solar Power Plants with Parabolic Trough Concentrators

10.5772/54060 ◽  
2013 ◽  
Author(s):  
Valentina A. ◽  
Carmelo E. ◽  
Giuseppe M. ◽  
Rosa Di ◽  
Fabrizio Girardi ◽  
...  
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Thermal Storage ◽  
Parabolic Trough ◽  
Solar Power Plants ◽  
Conceptual Study

Comparison of Two-Tank Indirect Thermal Storage Designs for Solar Parabolic Trough Power Plants

2009 ◽  
Author(s):  
Joseph Kopp ◽  
R. F. Boehm
Keyword(s):  
Power Generation ◽  
Molten Salt ◽  
Heat Exchangers ◽  
Power Plants ◽  
Thermal Storage ◽  
Heat Transfer Fluid ◽  
Base Case ◽  
Parabolic Trough ◽  
Trade Offs ◽  
Solar Field

The performance of a solar thermal parabolic trough plant with thermal storage is dependent upon the arrangement of the heat exchangers that ultimately transfer energy from the sun into steam. An indirect two-tank molten salt storage system that only transfers heat with the solar field heat transfer fluid is the most commercially acceptable thermal storage design. Annual electricity generation from two differing indirect two-tank molten salt storage designs and a base case with no thermal storage were modeled. Four components were characterized in a quasi-steady state analysis dependent upon key ambient and operational parameters: solar field, storage, heat exchangers, and power block. The parameters for the collector field remained constant for all models and were based on the SEGS VI plant. The results of net power generation favor storage though the design that maximizes annual output depends on whether maximum power generation or power generation during the evening peak demand hours is desired. Additionally, the economic trade offs are discussed for the three arrangements.

Adopting Nitrate/Nitrite Salt Mixtures as the Heat Transport Fluid in Parabolic Trough Power Plants

2007 ◽  
Author(s):  
Bruce Kelly ◽  
Henry Price ◽  
Doug Brosseau ◽  
David Kearney
Keyword(s):  
Heat Transport ◽  
Power Plants ◽  
Unit Cost ◽  
Thermal Storage ◽  
Outlet Temperature ◽  
Salt Mixture ◽  
Parabolic Trough ◽  
Demonstration Program ◽  
Salt Mixtures ◽  
Transport Fluid

The present generation of commercial parabolic trough solar power plant uses a synthetic oil as the heat transport fluid in the collector field. The plants are currently operating at the upper temperature limit of the fluid, and further improvements in the solar-to-electric conversion efficiency are likely to be incremental. In contrast, adoption of a nitrate salt, or a nitrate/nitrite salt, mixture as the heat transport fluid would allow the collector field outlet temperature to increase by 50 to 100 °C, which translates into an increase in the gross Rankine cycle efficiency from the present 37.5 percent to new values in the range of 40 to 41 percent. Further, the low cost and the low vapor pressure of the candidate salt mixtures allow the heat transport fluid to also act as the storage medium in a thermal storage system. Using a salt mixture in the collector field should reduce the unit cost of thermal storage by approximately half compared to the current indirect designs. The principal, and far from minor, liability of the candidate salt mixtures are freezing points in the range of 120 °C to 220 °C. As a consequence, all salt components, including the collector field, will require some form of electric heating for freeze protection. Further, collector designs will need to be demonstrated, or developed, which are tolerant of a limited number of freeze/thaw cycles. The candidate salts are also corrosive to the current ball joint sealing materials. This paper outlines the problems which need to be solved before a commercial salt project could reasonably be considered by a project developer, the elements of a test and demonstration program to solve the problems, and the contributions which will be necessary from the salt component vendors, the project developers, and the financial community.

Advanced Thermal Energy Storage Technology for Parabolic Trough

Solar Energy ◽  
2003 ◽  
Author(s):  
Rainer Tamme ◽  
Doerte Laing ◽  
Wolf-Dieter Steinmann
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Heat Storage ◽  
Storage Systems ◽  
Storage System ◽  
Discharge Process ◽  
Sensible Heat ◽  
Parabolic Trough ◽  
Storage Unit ◽  
Solid Media

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.

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 Comparative system analysis of direct steam generation and synthetic oil parabolic trough power plants with integrated thermal storage

Solar Energy ◽  
2012 ◽  
Vol 86 (1) ◽  
pp. 520-530 ◽  
Author(s):  
Jan Fabian Feldhoff ◽  
Kai Schmitz ◽  
Markus Eck ◽  
Lars Schnatbaum-Laumann ◽  
Doerte Laing ◽  
...  
Keyword(s):  
Power Plants ◽  
System Analysis ◽  
Thermal Storage ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Synthetic Oil ◽  
Direct Steam

Advanced Thermal Energy Storage Technology for Parabolic Trough

2004 ◽  
Vol 126 (2) ◽  
pp. 794-800 ◽  
Author(s):  
Rainer Tamme ◽  
Doerte Laing ◽  
Wolf-Dieter Steinmann
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Heat Storage ◽  
Storage Systems ◽  
Storage System ◽  
Discharge Process ◽  
Sensible Heat ◽  
Parabolic Trough ◽  
Storage Unit ◽  
Solid Media

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.

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.

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