Thousand kW High-Temperature Solar Furnace in Parkent (Uzbekistan) – Energetical Characteristics

This chapter presents a method of calculation of the energetical characteristics of the large solar furnace with a capacity of 1000 kW (LSF) taking into account its real optical parameters. The technical characteristics of the LSF are presented. The possible energy characteristics of the LSF based on numerical calculations are analyzed. The energy characteristics of the total system with different inaccuracies of the reflecting surfaces, energy contributions of certain shelves and groups of heliostats, and the contributions of certain heliostats and shapes of their focal spot are determined. Empirical formulas are proposed to describe the obtained numerical results. The problem of implementing the possible energy modes of the LSF with and/or without the inclusion of certain shelves and groups of heliostats is analyzed. The problem of a day changes in the energy density distribution in the focal spot of the LSF is considered

Integration of the solar thermal energy for the blast preheating in the copper smelting process

Treball Final de Grau en Enginyeria Química. Codi: EQ1044. Curs acadèmic: 2018/2019This work treats the subject of integrating a Central Tower System (SCT) as a source of thermal energy in the preheating of the blast of an Outokumpu Flash Furnace. The economic profitability of the process, as well as the environmental impact, are evaluated in addition to the analysis of the smelting process and the consequences of preheating the blast using solar thermal energy. The simulations developed in this work show clearly how removing the oil as an input of the process greatly reduce the volume of gases inside de furnace, allowing a higher feed rate and hence increasing the production and the profitability. As a contra, the removal of the fossil fuel implicates further enriching the blast in oxygen and/or preheating the blast. As the industrial oxygen is a source of economic losses for the process, and regarding the environmental impact of producing industrial oxygen, the preheating of the blast up to 600 K allows a reduction of the 17.43 mass-% of industrial oxygen. This would mean saving up to $2,443,878 per year in oil and industrial oxygen if we suppose that the copper production is kept constant at 75 ton per hour independently of the temperature of the preheating. On the other side, it has been noticed that preheating the blast expands greatly the volume of the gases inside the furnace, consequently reducing the production of copper and sulfuric acid, the two sources of economic incomes. If the down in the production is considered in the economic analysis, the results show that the inversion in a SCT system wouldn’t be economically profitable. Regarding the performance of the SCT system, it’s perfectly suitable for the preheating of the blast up to 1200 K. Without storage system, it would be possible to reach the energetic needs for the preheating 7 hours per day in average, providing around 4 MW in the case of preheating up to 600 K

Development of a high concentration solar flux mapping system.

Masters Degree. University of KwaZulu-Natal, Durban.The Group for Solar Energy Thermodynamics (GSET) is in the process of commissioning the Solar Energy Research Amplified Flux Facility (SERAFF), which is South Africa’s first solar furnace facility. SERAFF is situated at the University of KwaZulu-Natal’s Howard College campus and assumes an on-axis optical configuration, comprising a 9 m2 non-focusing heliostat reflector, a 3 m diameter paraboloidal dish concentrator and a test article platform. The facility was designed to aid research in the fields of high temperature materials testing, concentrating solar energy and solar thermochemistry. The concentrated radiative energy output of a solar furnace establishes the energy input to prototype receivers, reactors or materials that aim to be tested using the facility. The challenge is compounded by the temporal and spatial variation of SERAFF’s radiative energy output, influenced by weather-related and geometric factors. In this study, an indirect spatial flux mapping system is developed to characterise SERAFF’s spatial radiative energy output. SERAFF’s theoretical spatial radiative energy output is estimated through Monte Carlo ray-tracing techniques to provide benchmark performance parameters including total thermal power output, peak concentration ratio and focal spot size. The indirect system uses optical measurement techniques, in which spatial solar flux is measured via diffuse reflection off a Lambertian target using a digital CMOS camera through a neutral density filter and lens. Pixel intensities are calibrated against reference measurements acquired from a circular-foil Gardon gauge heat flux transducer. The calibrated CMOS camera can be used to measure values of radiative flux, incident at the focal plane from 0 kW/m2 - 468.19 kW/m2. Measurements were restricted to a brief testing period and are not representative of SERAFF’s peak operating conditions. Spatial flux measurements indicated a thermal power output of 3.83 kW, with a corresponding peak solar flux of 227.8 kW/m2 within a focal diameter of 250 mm. The study demonstrated successful integration of an indirect spatial flux mapping system into the SERAFF solar furnace

ERDA's central receiver solar thermal power system studies

The utilization of solar energy for electrical power production was studied. Efforts underway on the central receiver solar thermal power system are presented. Preliminary designs are included of pilot plant utilizing large numbers of heliostats in a collector field. Safety hazards are also discussed, as well as the most beneficial location of such a plant within the United States

Annual performance analysis and optimization of a solar tower aided coal-fired power plant

The integration of solar energy into coal-fired power plants has been proven as a potential approach in the utilization of solar energy to reduce coal consumption. Moreover, solar augmentation offers low cost and low risk alternatives to stand-alone solar thermal power plants. In this study, the annual performance of a solar tower aided coal-fired power (STACP) system is investigated, and the influence of thermal storage system capacity on the annual solar generating power and annual solar-to-electricity efficiency is explored. The thermal storage system capacity is optimized to obtain the lowest levelized cost of electricity (LCOE). At the same time, the influence and sensitivity of several important economic factors are explored and assessed. Results demonstrate that compared to a coal-fired power system, the reduction in the annual average coal consumption rate of the STACP system with high direct normal irradiance (DNI), medium DNI, and low DNI are 5.79, 4.52, and 3.22 g/kWh, respectively. At a minimum, the annual coal consumption can be reduced by 14,000 t in a 600 MWe power generation unit. Because the same solar field is considered under different DNI conditions, the LCOE in the high DNI, medium DNI, and low DNI scenarios are all fairly similar (6.37, 6.40, and 6.41 ¢/kWh, respectively). When the solar multiple is 3.0, the optimal thermal storage capacity of the STACP system, with high, medium, and low DNIs are 6.73, 4.42, and 2.21 h, respectively. The sensitivity analysis shows that the change in economic parameters exerts more influence on the STACP system with the high DNI compared with the other two scenarios

Durability of reflecting surfaces used in solar heliostats

Issued as Project status reports no. 2-9, and Final report, Project no. A-2916Library does not have: Project status report no.

Manufacturing with the Sun

Concentrated solar radiation is now a viable alternative source for many advanced manufacturing processes. Researchers at the National Renewable Energy Laboratory (NREL) have demonstrated the feasibility of processes such as solar induced surface transformation of materials (SISTM), solar based manufacturing, and solar pumped lasers. Researchers are also using sunlight to decontaminate water and soils polluted with organic compounds; these techniques could provide manufacturers with innovative alternatives to traditional methods of waste management. The solar technology that is now being integrated into today's manufacturing processes offer greater potential for tomorrow, especially as applied to the radiation abundant environment available in space and on the lunar surface

Techniques to Measure Solar Flux Density Distribution on Large-Scale Receivers

Flux density measurement applied to central receiver ystems delivers the spatial distribution of the concentrated solar radiation on the receiver aperture, measures receiver input power, and monitors and might control heliostat aimpoints. Commercial solar tower plants have much larger aperture surfaces than the receiver prototypes tested in earlier research and development (R&D) projects. Existing methods to measure the solar flux density in the receiver aperture face new challenges regarding the receiver size. Also, the requirements regarding costs, accuracy, spatial resolution, and measuring speed are different. This paper summarizes existent concepts, presents recent research results for techniques that can be applied to large-scale receivers and assesses them against a catalog of requirements. Direct and indirect moving bar techniques offer high measurement accuracy, but also have the disadvantage of large moving parts on a solar tower. In the case of external receivers, measuring directly on receiver surfaces avoids moving parts and allows continuous measurement but may be not as precise. This promising technique requires proper scientific evaluation due to specific reflectance properties of current receiver materials. Measurement-supported simulation techniques can also be applied to cavity receivers without installing moving parts. They have reasonable uncertainties under ideal conditions and require comparatively low effort

Development of a CST system based on a solid particle receiver, optimised for commercialisation in the Australian market

This thesis explores a recently developed concentrated solar thermal (CST) central receiver technology, known as the solid particle receiver (SPR). Calculations of long and near term thermo-economic competitiveness for promising potential applications were preformed, for the first time within the Australian context. With these results, the most suitable SPR technology configurations and technical developments, required to reach the commercial potential, were identified. An innovative simulation tool which included a variety of different thermodynamic and economic models, was developed to compute the annual performance of solar SPR systems. This simulation tool was then applied to design and to optimise CST SPR tower systems based on hourly simulations utilising meteorological data, the NREL Solar Position Algorithm, solar field efficiency matrices generated by DLR software HFLCAL, as well as a mathematical SPR model for calculating receiver efficiency. The SPR model was calibrated using results from DLR receiver prototype tests. To allow economic assessment of the entire SPR system, a financial model was implemented within the tool and detailed CST component costs were generated. The optimisation process utilised in the CST tower system design is more detailed than typical for a research project, since it adds a new degree of freedom when optimising the receiver and solar field. By decoupling the connection between solar field and receiver, the energy delivered from the solar field relative to the design receiver power becomes an additional optimisation variable. Applications of SPR systems for electricity production and industrial process heat generation have been identified for the Australian market. Promising heat supply uses of SPR technology examined in this thesis were: thermal enhanced oil recovery, preheating scrap metal during steel production, and solar augmentation of coal-fired steam power stations. Before this project, there were no detailed investigations on utilising SPR based CST power plants in Australia. This thesis has identified several potential applications, the required sub-components and system integration methods which should be further developed for commercialisation of this solar technology in the Australian market