scholarly journals Performance Assessment and Improvement of Central Receivers Used for Solar Thermal Plants

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3079 ◽  
Author(s):  
Albarbar ◽  
Arar

In this work, the energy status and supply plans of Saudi Arabia are discussed with a focus on concentrated solar power (CSP) technologies. Subsequently, optimal designs for a 20 MWe solar power plant external receiver, combined with a 15 h thermal energy storage unit, operating under the weather conditions of Neom City, located in northeast Saudi Arabia, is proposed. The effects of receiver tube diameters, tube thicknesses, tube thermal conductivity and receiver’s performance are studied in detail and compared to those used in a well know operational CSP plant. Results show that a smaller tube diameter and thickness give higher receiver thermal efficiency but increase the annual cost of pumping energy. However, that increment in cost is negligible compared to the total energy gained. Furthermore, the aspect ratio is investigated and it was found that a higher aspect ratio gives a higher thermal efficiency. The thermal efficiency of the optimised receiver was increased by about 1% more than the reference plant. In addition, the new design decreases the total estimated cost of tube material by approximately 43%. It is anticipated that the reported results could pave the path for more efficient solar thermal power plants.

2017 ◽  
Vol 2 (2) ◽  
pp. 18
Author(s):  
Taqiy Eddine Boukelia

Most of Concentrating Solar Power (CSP) plants are usually installed in desert regions where water resource availability is a critical limitation due to the lack of water required for the exploitation of these systems in these regions. Therefore, the aim of this study is to investigate the techno-economic competitiveness of deploying both modes of cooling (wet and dry) in two different parabolic trough solar thermal power plants integrated with thermal energy storage and fuel backup system; the first one is using thermic oil, while the other is working using molten salt. The obtained results show that the dry cooling mode can decrease the yields of the two power plants down to 8.7 % and 9.3 % for oil and salt configurations respectively. On the other hand, the levelized cost of electricity can increase by using this cooling option up to 9.3 % for oil plant, and 10.0 % for salt one. However, the main advantage of using dry cooling option is reducing water consumption which has been decreased by more than 94 % for both plants. The application of our methodology to other two sites worldwide, confirms the viability of the obtained results. The importance of this results is to show the effect of working fluids on the cooling system of solar power plants.


2012 ◽  
Vol 236-237 ◽  
pp. 714-719
Author(s):  
Wei Lan ◽  
Bin Wang ◽  
Yi Ming Feng

Nowadays, the high-speed economic development has caused significant consumption of energy. While the circumstance is getting severer, solar energy is taken as a kind of clean, environmental friendly resource with infinite storage that has aroused a wide public concern. Photovoltaic and solar thermal are two main categories of solar applications. Because of its high conversion efficiency, low emission and flexible installation, dish Stirling solar power technology is more preferable to be used among the solar thermal area. From the view of practical engineering application, this paper illustrates multiple focusing methods of the current dish Stirling solar power systems in detail, and the comparison of these methods are given to analyze their advantages, disadvantages and their application scenarios. It can be used for the future development of dish Stirling solar power technology and applied as a reference for large dish solar thermal power plants’ installations and tests.


2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Jesús M. Lata ◽  
Manuel Rodríguez ◽  
Mónica Álvarez de Lara

Molten salt technology represents nowadays the most cost-effective technology for electricity generation for stand-alone solar power plants. Although this technology can be applied to both concentrating technologies, parabolic through and central receiver systems (CRSs), CRS technology can take advantages from its higher concentration, allowing to work at higher temperatures and therefore with a reduction in the size and cost of the storage system. The receiver system is the “door” for which the energy passes from the field collector to the thermal-electric cycle; it represents, therefore, the core of the CRS and its performance directly affects plant production. Starting from the published lessons from SOLAR TWO receiver technology, the validation of an improved receiver for molten salt technology was assumed as part of the SOLAR TRES solar thermal power commercial plant development. Main challenges for the new receiver were to increase its allowable peak flux up to 1MW∕m2 in order to maximize the thermal efficiency of the CRS solar power plant, and to improve its safe life without limiting the incident fluxes that the field of heliostats is able to deliver with an optimized pointing strategy. Several advanced features in geometric and thermodynamic aspects and in its material selection have been implemented on the receiver. With the results of a sensitivity analysis carried out with an own code developed by SENER (SENREC), a prototype receiver panel was designed, fabricated, and installed in a proper test bed at the PSA. Test validation on this panel was carried out in 2007. The initial test results show a very good behavior of the prototype receiver, which allows to anticipate that the objectives of its design can be fulfilled. SENER and CIEMAT have joined forces to face up the challenge of sizing and designing a new molten salt receiver of high thermal efficiency, able to operate at high fluxes without compromising its durability (at least 25years). Main challenges for the new receiver design were to optimize the receiver dimensions and receiver tube sizes and material selection to surpass the operating conditions in the new plants with respect to SOLAR TWO.


2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Brandon Duquette ◽  
Todd Otanicar

One of the noted benefits of concentrating photovoltaics (PV) is the reduced cell area which results in reduction of the overall system cost. A variety of studies have looked at the cost for concentrating PV systems and made comparisons to concentrating solar thermal power plants, typically resulting in concentrating solar thermal power having lower system costs. Recently, a widespread design space was assessed for the potential efficiency improvements possible with a coupled hybrid PV/thermal solar energy system for electricity generation. The analysis showed that modest efficiency improvements could be made but no assessment of the economic impact was made. Although modest efficiency gains can be made, such a hybrid system requires more components than one of the conventional stand alone concentrating solar power plant on its own resulting in significantly different system costs. As a result, we look to compare the overall system costs of three different solar power technologies: concentrating PV, concentrating solar thermal, and the concentrating hybrid approach. Additionally, we will focus on documenting the necessary hybrid efficiencies to make a hybrid system competitive as well as the feasibility and means for achieving these efficiencies.


Author(s):  
Brandon Duquette ◽  
Todd Otanicar

One of the noted benefits of concentrating photovoltaics (PV) is the reduced cell area which results in reduction of the overall system cost. A variety of studies have looked at the cost for concentrating PV systems and made comparisons to concentrating solar thermal power plants, typically resulting in concentrating solar thermal power having lower system costs. Recently a widespread design space was assessed for the potential efficiency improvements possible with a coupled hybrid PV/thermal solar energy system for electricity generation. The analysis showed that modest efficiency improvements could be made but no assessment of the economic impact was made. Although modest efficiency gains can be made such a hybrid system requires more components than one of the conventional stand alone concentrating solar power plant on its own resulting in significantly different system costs. As a result we look to compare the overall system costs of three different solar power technologies: concentrating PV, concentrating solar thermal, and the concentrating hybrid approach. Additionally we will focus on documenting the necessary hybrid efficiencies to make a hybrid system competitive as well as the feasibility and means for achieving these efficiencies.


Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini

Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on synthetic oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex®, with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and synthetic oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.


2015 ◽  
Vol 1116 ◽  
pp. 94-129 ◽  
Author(s):  
Maimoon Atif ◽  
Fahad A. Al-Sulaiman

This chapter starts with a background about concentrating solar power systems and thermal energy storage systems and then a detailed literature review about concentrated solar power systems and supercritical Brayton carbon dioxide cycles. Next, a mathematical model was developed and presented which generates and optimizes a heliostat field effectively. This model was developed to demonstrate the optimization of a heliostat field using differential evolution, which is an evolutionary algorithm. The current model illustrates how to employ the developed model and its advantages. The optimization process calculates the optical performance parameters at every step of the optimization considering all the heliostats; thus yields accurate results as discussed in this chapter. On the other hand, complete mathematical model of supercritical CO2Brayton cycles when integrated with solar thermal power tower system was presented and discussed.


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