Optical Analysis of the Fixed Mirror Solar Concentrator by Forward Ray-Tracing Procedure

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Ramon Pujol Nadal ◽  
Víctor Martínez Moll
Keyword(s):  
Ray Tracing ◽  
Power Plants ◽  
Thermal Power ◽  
Production Costs ◽  
Electricity Production ◽  
Design Parameters ◽  
Solar Concentrator ◽  
Optical Efficiency ◽  
3D Ray Tracing ◽  
Positive Effect

The fixed mirror solar concentrator (FMSC) is a mobile focus concentrator whose design emerged in the 1970s in an effort to reduce electricity production costs in solar thermal power plants. This geometry has not yet been analyzed with 3D ray-tracing procedures. The geometry of FMSC is defined using three parameters: the number of mirrors N, the ratio of focal length and reflector width F/W, and the intercept factor γ (in order to represent different receiver widths). For the analysis, a 3D ray-tracing code that allows the characterization of solar concentrators was developed. A standard evacuated tube was used as a receiver. The geometric concentration ratio, the optical efficiency, and the transversal and longitudinal incidence angle modifier (IAM) curves for different values of design parameters were calculated. High concentrations imply low F/W values and for high efficiencies, large intercept factor values are required. Increasing the F/W ratio has a positive effect on the transversal IAM, yet a negative one for the longitudinal IAM. Increasing the number of mirrors has a negative effect on both IAM curves due to the self-shadowing between the adjacent steps. Increasing the intercept factor only has a significant positive effect on the longitudinal IAM. The goodness of the IAM factorization approach was analyzed, and it was found that it can be used as long as a new correction factor to account for the focus displacement is introduced. The results presented in this paper provide information, in form of curves, regarding the optical behavior of the FMSC in terms of different design parameters in order to know the possibility to use the FMSC in medium range temperature applications.

A study of the effect of design parameters on the performance of linear solar concentrator based thermal power plants in India

2016 ◽  
Vol 87 ◽  
pp. 666-675 ◽  
Author(s):  
Chandan Sharma ◽  
Ashish K. Sharma ◽  
Subhash C. Mullick ◽  
Tara C. Kandpal
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Design Parameters ◽  
Thermal Power Plants ◽  
Solar Concentrator

Comparison of Two Linear Collectors in Solar Thermal Plants: Parabolic Trough vs Fresnel

2011 ◽  
Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Research Activity ◽  
Optical Efficiency ◽  
Synthetic Oil ◽  
Yearly Average

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.

The CFD Design and Optimisation of a 100 kW Hydrogen Fuelled mGT

2020 ◽  
Author(s):  
Cedric Devriese ◽  
Gijs Penninx ◽  
Guido de Ruiter ◽  
Rob Bastiaans ◽  
Ward De Paepe
Keyword(s):  
Combustion Chamber ◽  
Power Plants ◽  
Internal Combustion Engines ◽  
Cone Angle ◽  
Electricity Production ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Large Power ◽  
Power Sources ◽  
The Impact

Abstract Against the background of a growing deployment of renewable electricity production, like wind and solar, the demand for energy storage will only increase. One of the most promising ways to cover the medium to long-term storage is to use the excess electricity to produce hydrogen via electrolysis. In a modern energy grid, filled with intermittent power sources and ever-increasing problems to construct large power plants in densely populated areas, a network of Decentralised Energy Systems (DES) seems more logical. Therefore, the importance of research into the design of a small to medium-sized hydrogen fuelled micro Gas Turbine (mGT) unit for efficient, local heat and electricity production becomes apparent. To be able to compete with Reciprocating Internal Combustion Engines (RICEs), the mGT needs to reach 40% electrical efficiency. To do so, there are two main challenges; the design of an ultra-low NOX hydrogen combustor and a high Turbine Inlet Temperature (TIT) radial turbine. In this paper, we report on the progress of our work towards that goal. First, an improvement of the initial single-nozzle swirler (swozzle) combustor geometry was abandoned in favour of a full CFD (steady RANS) design and optimisation of a micromix type combustion chamber, due to its advantages towards NOx-emission reduction. Second, a full CFD design and optimisation of the compressor and turbine is performed. The improved micromix combustor geometry resulted in a NOx level reduction of more than 1 order of magnitude compared to our previous swozzle design (from 1400 ppm to 250 ppm). Moreover, several design parameters, such as the position and diameter of the hydrogen injection nozzle and the Air Guiding Panel (AGP) height, have been optimized to improve the flow patterns. Next to the combustion chamber, CFD simulations of the compressor and turbine matched the 1D performance calculations and reached the desired performance goals. A CFD analysis of the impact of the tip gap and exhaust diffuser cone angle led to a choice of these parameters that improved the compressor and turbine performance with a limited loss in efficiency.

Comparison of Two Linear Collectors in Solar Thermal Plants: Parabolic Trough Versus Fresnel

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
The United States ◽  
Solar Thermal ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Annual Average ◽  
Optical Efficiency ◽  
Levelized Cost Of Electricity ◽  
Synthetic Oil

Parabolic trough (PT) technology can be considered the state of the art for solar thermal power plants thanks to the almost 30 yr of experience gained in SEGS and, recently, Nevada Solar One plants in the United States and Andasol plant 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, research has focused on developing new solutions that aim to reduce costs. This paper compares, at nominal conditions, commercial Fresnel technology for direct steam generation with conventional parabolic trough technology based on synthetic oil as heat-transfer. The comparison addresses nominal conditions as well as annual average performance. In both technologies, no thermal storage system is considered. Performance is calculated by Thermoflex®, a commercial code, with a dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology has an optical efficiency of 67%, which is lower than the 75% efficiency of the parabolic trough. Calculated net electric efficiency is about 19.25%, whereas PT technology achieves 23.6% efficiency. In off-design conditions, the performance gap between Fresnel and parabolic trough increases because the former is significantly affected by high incident angles of solar radiation. The calculated sun-to-electric annual average efficiency for a Fresnel plant is 10.2%, which is a consequence of the average optical efficiency of 38.8%; a parabolic trough achieves an overall efficiency of 16%, with an optical efficiency of 52.7%. An additional case with a Fresnel collector and synthetic-oil outlines the differences among the cases investigated. Since part of the performance difference between Fresnel and PT technologies is simply due to different definitions, we introduce additional indexes to make a consistent comparison. Finally, a simplified economic assessment shows that Fresnel collectors must reduce investment costs of at least 45% than parabolic trough to achieve the same levelized cost of electricity.

scholarly journals Functional Features of National Thermal Power Plantsunder Sustainable Development Conditions

2018 ◽  
Keyword(s):  
Sustainable Development ◽  
Electricity Generation ◽  
Power Plants ◽  
Thermal Power ◽  
Market Model ◽  
Electricity Production ◽  
Thermal Power Plants ◽  
The Sustainable Development ◽  
Energy Independence ◽  
Functional Features

The paper is devoted to analysis of functional peculiarities of thermal power plants in Ukraine. In the course of the study, key determinants of the sustainable development of domestic electricity generation were identified in the context of transition to a new market model. The preconditions of activation and support of the sustainable development concept implementation process in the modern business practice of the energy sector enterprises within the Ukrainian economy are outlined. The theoretical and practical bases for ensuring the sustainable development of energy in relation to other United Nations Declarations of Sustainable Development are indicated. The comparative estimation of the efficiency level of state policy in scope of energy independence and resource conservation with the use of a complex indicator of GDP energy intensity is given. On the basis of international and domestic statistical data the dynamics of volumes of electricity production in Ukraine for the period of 1990-2017 as well as the structure of electricity generation by type of generation were analyzed. The dynamics of electric power generation in Ukraine by types of raw materials was presented in complex with the dynamics of coal consumption and production for the corresponding period. The peculiarities of thermal power plants functioning in comparison with other power generating enterprises in modern conditions are specified. The key element of Ukraine’s energy independence – the volume of proven coal reserves – is a prerequisite for the efficient functioning of domestic thermal power plants. The pricing features in the sphere of electricity production and sales are outlined, in particular, the structure of market rate and the price of electricity sales by producers to the Wholesale Market are presented. The significance of the innovation factor in the process of improving the efficiency of thermal power plants functioning has been substantiated, taking into account the economic, social and environmental aspects of their production and economic activity.

scholarly journals Comparison of the most likely low-emission electricity production systems in Estonia

2021 ◽  
Author(s):  
Zachariah Baird ◽  
Dmitri Neshumayev ◽  
Oliver Järvik ◽  
Kody M. Powell
Keyword(s):  
Energy Storage ◽  
Wind Turbines ◽  
Nuclear Power ◽  
Oil Shale ◽  
Power Plants ◽  
Thermal Power ◽  
Carbon Capture And Storage ◽  
Electricity Production ◽  
Levelized Cost Of Electricity ◽  
Low Emission

To meet targets for reducing greenhouse gas emissions, many countries, including Estonia, must transition to low-emission electricity sources. Based on current circumstances, the most likely options in Estonia are renewables with energy storage, oil shale power plants with carbon capture and storage (CCS), or the combination of renewables and either oil shale or nuclear power plants. Here we compare these different scenarios to help determine which would be the most promising based on current information. For the comparison we performed simulations to assess how various systems meet the electricity demand in Estonia and at what cost.Based on our simulation results and literature data, combining wind turbines with thermal power plants would provide grid stability at a more affordable cost. Using nuclear power to compliment wind turbines would lead to an overall levelized cost of electricity (LCOE) in the range of 68 to 150 EUR/MWh (median of 103 EUR/MWh). Using oil shale power plants with CCS would give a cost between 91 and 163 EUR/MWh (median of 118 EUR/MWh). By comparison, using only renewables and energy storage would have an LCOE of 106 to 241 EUR/MWh (median of 153 EUR/MWh).

Early-Warning System for Power Coal Storage and Supply Margin of Henan Province

2013 ◽  
Vol 291-294 ◽  
pp. 2366-2374
Author(s):  
Ye Fei Liu ◽  
Huan Qi ◽  
Su Qin Sun
Keyword(s):  
Early Warning ◽  
Early Warning System ◽  
Power Plants ◽  
Thermal Power ◽  
Warning System ◽  
Electrical Energy ◽  
Henan Province ◽  
Electricity Production ◽  
Policy Makers ◽  
Fuel Storage

China's needs of energy increased dramatically in these years. In China, Electrical energy are mainly generated by thermal power plants that use coal as fuel, thus electricity supply are linked to the power fuel (coals) storage of power plants. Henan has been changed form an energy exporter province to an energy importer province. Therefore, the fuel storage and supply of power plants are keys to the security of the province's social development, economics and energy supply. Research the margin of power fuel storage and supply can help the policy makers to learn the security conditions and trends of electricity production microscopically, reducing the risks in the power production process, and improving the efficiency of production and the efficiency of energy. Environmental and economic issues brought by the excessive storage can be reduced. This article describes the ideas and development of early warning system for power fuel storage and supply margin of Henan province.

Annual Simulation of the Thermal Performance of Solar Power Plant for Electricity Production Using TRNSYS

2016 ◽  
Author(s):  
Mohamed H. Ahmed ◽  
Alberto Giaconia ◽  
Amr M. A. Amin
Keyword(s):  
Power Plant ◽  
Steam Generator ◽  
Thermal Performance ◽  
Storage Tank ◽  
Solar Power ◽  
Heat Energy ◽  
Electricity Production ◽  
Design Parameters ◽  
Solar Power Plant ◽  
Solar Concentrator

The process of generating electricity using solar energy took a great interest in the recent period for its contribution to the reduction of the fossil fuel consumption and the harmful emissions to the environment. The main task of this article is to simulate the thermal performance of a solar power plant for electricity production using a parabolic trough concentrator for accumulating the solar heat. The plant includes a stratified storage tank, steam generator, steam turbine and an electric generator. The simulation studies the effect of the design parameters of the solar field and the storage tank on the annual performance of a 1 MWe solar electric power plant. The simulation platform TRNSYS was used to model the solar power plant including the solar concentrator field, the storage tank, and the steam generator. The simulation predicts the instantaneous and annual heat energy collected by the solar concentrator and the heat energy rate supplied, extracted, and stored in the storage tank. It predicts also the rate and the quality of the steam produced. This analysis was applied to four sites in Egypt to study the effect of the solar radiation on the energy produced in those sites.

scholarly journals Process Development of Fly Ash-Based Geopolymer Mortars in View of the Mechanical Characteristics

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2935
Author(s):  
Hatice Öznur Öz ◽  
Neslihan Doğan-Sağlamtimur ◽  
Ahmet Bilgil ◽  
Aykut Tamer ◽  
Kadir Günaydin
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Process Development ◽  
Thermal Power ◽  
Weight Ratio ◽  
Curing Temperature ◽  
Design Parameters ◽  
Alkaline Solutions ◽  
Solid Ratio ◽  
Flexural Tests

This study aimed to determine the effects of design parameters, including the liquid/solid ratio (L/S), Na2SiO3/NaOH weight ratio, and curing temperature, on class F fly ash-based geopolymer composites. For this purpose, two disparate sources of fly ash were supplied from Çatalağzı (FA) and İsken Sugözü (FB) Thermal Power Plants in Turkey. Two different L/S ratios of 0.2 and 0.4 were used. The Na2SiO3/NaOH ratios in the alkaline solutions were 1, 1.5, 2, 2.5, and 3 by weight for each type of geopolymer mixture. Then, 40 different mixes were cured at two specific temperatures (70 °C and 100 °C) for 24 h and then preserved at room temperature until testing. Thereafter, the physical water absorption properties, apparent porosity, and bulk density were examined at 28 days on the hardened mortars. Additionally, compressive and flexural tests were applied to the geopolymers at 7, 28, and 90 days. It was found that the highest compressive strength was 60.1 MPa for the geopolymer manufactured with an L/S of 0.2 and Na2SiO3/NaOH ratio of 2. Moreover, the best thermal curing temperature for obtaining optimal strength characteristics was 100 °C for the FB.

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