scholarly journals Heliostat Cost Reduction

Author(s):  
Gregory J. Kolb ◽  
Roger Davenport ◽  
David Gorman ◽  
Ron Lumia ◽  
Robert Thomas ◽  
...  

Power towers are capable of producing solar-generated electricity and hydrogen on a large scale. Heliostats are the most important cost element of a solar power tower plant. Since they constitute ∼50% to the capital cost of the plant it is important to reduce the cost of heliostats to as low as possible to improve the economic viability of power towers. In this study we evaluate current heliostat technology and estimate a price of $126/m2 given year 2006 materials and labor costs. We also propose R&D that should ultimately lead to a price of less than $100/m2. Approximately 30 heliostat and manufacturing experts from the USA, Europe, and Australia contributed to the content of this report during 2 workshops conducted at the National Solar Thermal Test Facility.

1994 ◽  
Vol 116 (3) ◽  
pp. 137-141 ◽  
Author(s):  
D. C. Smith ◽  
E. E. Rush ◽  
C. W. Matthews ◽  
J. M. Chavez ◽  
P. A. Bator

The molten salt pump and valve (P&V) test loops at Sandia National Laboratories (SNL) National Solar Thermal Test Facility (NSTTF) operated between Jan. 1988 and Oct. 1990. The purpose of the P&V test was to demonstrate the performance, reliability, and service life of full-scale hot and cold salt pumps and valves for use in commercial central receiver solar power plants. The P&V test hardware consists of two pumped loops; the “Hot Loop” to simulate the hot (565°C) side of the receiver and the “Cold Loop” to simulate the receiver’s cold (285°C) side. Each loop contains a pump and five valves sized to be representative of a conceptual 60-MWe commercial solar power plant design. The hot loop accumulated over 6700 hours of operation and the cold loop over 2500 hours of operation. This project has demonstrated that standard commercial scale pump and valve designs will work in molten salt. The test also exposed some pitfalls that must be avoided in specifying such equipment. Although certainly not all of the pitfalls were discovered, careful design and specification should result in reliable or at least workable equipment.


2014 ◽  
Vol 39 (1) ◽  
pp. 165-172
Author(s):  
Praveen Kumar Verma ◽  
SK Nag ◽  
SK Patil

The paper has studied the economic viability of improved technology (Introduced under NAIP component-3) for extraction of cashew kernel from cashew nut in Bastar region of Chhattisgarh, India. Cost concept has been used to calculate economics of cashew kernel. The technology (Boiling, steaming, cutting, drying, and peeling) has been found viable over conventional practices (Traditional manual separation by stone or hammer) on account of higher recovery of 40 percent and cost reduction by 29.71 percent. Overall net profit per unit (One unit includes one boiler, one steamer, two cutter, one dryer, six peelers and cost of land, depreciation and interest on working capital) in the case of improved technology has been estimated to be Rs 7.32 lakh. Cost of production in machine extraction practices was 202.80 Rupees per kilogram of cashew in spite of traditionally practiced 288.56 Rupees per kilogram. The cost benefit ratio was found higher in machine extraction (1.57) as compare to traditionally practiced (0.169). The mechanical decortications and separation could not only save time and money, also reduced women drudgery (due to manual breaking by stone or hammer to separate kernel). The technology has been found suitable for promotion of entrepreneurship on the processing of cashew kernel from cashew nut in the production catchments which otherwise is not properly utilized. DOI: http://dx.doi.org/10.3329/bjar.v39i1.20166 Bangladesh J. Agril. Res. 39(1): 165-172, March 2014


Author(s):  
Raffaele Capuano ◽  
Thomas Fend ◽  
Bernhard Hoffschmidt ◽  
Robert Pitz-Paal

Due to the continuous global increase in energy demand, Concentrated Solar Power (CSP) represents an excellent alternative, or add-on to existing systems for the production of energy on a large scale. In some of these systems, the Solar Power Tower plants (SPT), the conversion of solar radiation into heat occurs in certain components defined as solar receivers, placed in correspondence of the focus of the reflected sunlight. In a particular type of solar receivers, defined as volumetric, the use of porous materials is foreseen. These receivers are characterized by a porous structure called absorber. The latter, hit by the reflected solar radiation, transfers the heat to the evolving fluid, generally air subject to natural convection. The proper design of these elements is essential in order to achieve high efficiencies, making such structures extremely beneficial for the overall performances of the energy production process. In the following study, a parametric analysis and an optimized characterization of the structure have been performed with the use of self-developed numerical models. The knowledge and results gained through this study have been used to define an optimization path in order to improve the absorber microstructure, starting from the current in-house state-of-the-art technology until obtaining a new advanced geometry.


Solar Energy ◽  
2005 ◽  
Author(s):  
Gregory J. Kolb ◽  
Richard B. Diver ◽  
Nathan Siegel

Solar power towers can be used to make hydrogen on a large scale. Electrolyzers could be used to convert solar electricity produced by the power tower to hydrogen, but this process is relatively inefficient. Rather, efficiency can be much improved if solar heat is directly converted to hydrogen via a thermochemical process. In the research summarized here, the marriage of a high-temperature (∼1000 °C) power tower with a sulfuric acid/hybrid thermochemical cycle (SAHT) was studied. The concept combines a solar power tower, a solid-particle receiver, a particle thermal energy storage system, and a hybrid-sulfuric-acid cycle. The cycle is “hybrid” because it produces hydrogen with a combination of thermal input and an electrolyzer. This solar thermochemical plant is predicted to produce hydrogen at a much lower cost than a solar-electrolyzer plant of similar size. To date, only small lab-scale tests have been conducted to demonstrate the feasibility of a few of the subsystems and a key immediate issue is demonstration of flow stability within the solid-particle receiver. The paper describes the systems analysis that led to the favorable economic conclusions and discusses the future development path.


2006 ◽  
Vol 129 (2) ◽  
pp. 179-183 ◽  
Author(s):  
Gregory J. Kolb ◽  
Richard B. Diver ◽  
Nathan Siegel

Solar power towers can be used to make hydrogen on a large scale. Electrolyzers could be used to convert solar electricity produced by the power tower to hydrogen, but this process is relatively inefficient. Rather, efficiency can be much improved if solar heat is directly converted to hydrogen via a thermochemical process. In the research summarized here, the marriage of a high-temperature (∼1000°C) power tower with a sulfuric acid∕hybrid thermochemical cycle was studied. The concept combines a solar power tower, a solid-particle receiver, a particle thermal energy storage system, and a hybrid-sulfuric-acid cycle. The cycle is “hybrid” because it produces hydrogen with a combination of thermal input and an electrolyzer. This solar thermochemical plant is predicted to produce hydrogen at a much lower cost than a solar-electrolyzer plant of similar size. To date, only small lab-scale tests have been conducted to demonstrate the feasibility of a few of the subsystems and a key immediate issue is demonstration of flow stability within the solid-particle receiver. The paper describes the systems analysis that led to the favorable economic conclusions and discusses the future development path.


Author(s):  
Henry Price ◽  
David Kearney

Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. However, no new plants have been built during the past ten years because the cost of power from these plants is more expensive than power from conventional fossil fuel power plants. This paper reviews the current cost of energy and the potential for reducing the cost of energy from parabolic trough solar power plant technology based on the latest technological advancements and projected improvements from industry and sponsored R&D. The paper also looks at the impact of project financing and incentives on the cost of energy.


2006 ◽  
Vol 129 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Charles W. Forsberg ◽  
Per F. Peterson ◽  
Haihua Zhao

Liquid-fluoride-salt heat transfer fluids are proposed to raise the heat-to-electricity efficiencies of solar power towers to about 50%. The liquid salt would deliver heat from the solar furnace at temperatures between 700°C and 850°C to a closed multireheat Brayton power cycle using nitrogen or helium as the working fluid. During the daytime, hot salt may also be used to heat graphite, which would then be used as a heat storage medium to make night-time operations possible. Graphite is a low-cost high-heat-capacity solid that is chemically compatible with liquid fluoride salts at high temperatures. About half the cost of a solar power tower is associated with the mirrors that focus light on the receiver, and less than one-third is associated with the power cycle and heat storage. Consequently, increasing the efficiency by 20–30% has the potential for major reductions in the cost of electricity. Peak temperatures and efficiencies of current designs of power towers are restricted by (1) the use of liquid nitrate salts that decompose at high temperatures and (2) steam cycles in which corrosion limits peak temperature. The liquid-fluoride-salt technology and closed Brayton power cycles are being developed for high-temperature nuclear reactors. These developments may provide the technology and industrial basis for an advanced solar power tower.


2022 ◽  
pp. 1-51
Author(s):  
Lindsey Yue ◽  
Brantley Mills ◽  
Joshua M Christian ◽  
Clifford K. Ho

Abstract Falling particle receivers are an emerging technology for use in concentrating solar power systems. In this work, quartz half-shells are investigated for use as full or partial aperture covers to reduce receiver thermal losses. A receiver subdomain and surrounding air are modeled using ANSYS® Fluent®. The model is used to simulate fluid dynamics and heat transfer for the following cases: (1) open aperture, (2), aperture fully covered by quartz half-shells, and (3) aperture partially covered by quartz half-shells. We compare the percentage of total incident solar power lost due to conduction through the receiver walls, advective losses through the aperture, and radiation exiting the aperture. Contrary to expected outcomes, results show that quartz aperture covers can increase radiative losses and result in modest to nonexistent reductions in advective losses. The increased radiative losses are driven by elevated quartz half-shell temperatures and have the potential to be mitigated by active cooling and/or material selection. Quartz half-shell total transmissivity was measured experimentally using a radiometer and the National Solar Thermal Test Facility heliostat field. Average measured total transmissivities are 0.97±0.01 and 0.94±0.02 for concave and convex side toward the heliostat field, respectively. Quartz half-shell aperture covers did not yield expected efficiency gains in numerical results due to increased radiative losses, but efficiency improvement in some numerical results and the performance of quartz half-shells subject to concentrated solar radiation suggest quartz half-shell aperture covers should be investigated further.


Author(s):  
Jenny Nelson ◽  
Christopher J. M. Emmott

Solar power represents a vast resource which could, in principle, meet the world's needs for clean power generation. Recent growth in the use of photovoltaic (PV) technology has demonstrated the potential of solar power to deliver on a large scale. Whilst the dominant PV technology is based on crystalline silicon, a wide variety of alternative PV materials and device concepts have been explored in an attempt to decrease the cost of the photovoltaic electricity. This article explores the potential for such emerging technologies to deliver cost reductions, scalability of manufacture, rapid carbon mitigation and new science in order to accelerate the uptake of solar power technologies.


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