No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Theoretical design, material study and material selection for compact linear Fresnel reflector concentrating system
Abstract
A comparative study is made between two different Compact Linear Fresnel reflector concentrating (CLFRC) systems with tubular absorber. The CLFRC systems with constant width reflectors and varying width reflectors are taken for study. The systems are analyzed with design parameters and Material study. By varying various design parameters like width of the reflector plates, shift between the plates, the height of the receiver tube from the reflector plane and diameter of the receiver tube, by using the geometrical equations calculations are done using MATLAB and the optimum values are taken for the design. The solar flux is considered to be a constant of 0.6 kW/m². Concentrated ratio and concentrated flux are determined for each case to select the best system. Results show that the CLFRC system with constant width plates has better performance with concentration power, C.P = 3.15 kW and concentration ratio, C.R = 103.3 are better than those with varying width plates, while considering optimum design parameters of height from reflector plane, width of the plates and diameter of the receiver tube as 1.5 m, 0.03 m and 0.015 m respectively. The best system is selected through theoretical study and software analysis the system is modified with different reflectors (Glass mirror, Acrylic sheet, Chromium coated sheet, Polished Aluminum sheet) glass mirror is found to be the best reflector based on it reflectivity (ρ = 0.98) and the absorber is coated with different coating materials (Black Copper-Cu, Black Chrome- Ni-Cu/Steel, Black Nickel- Steel/Ni coated steel, Ni-Nox- Al) the best coating material is found to be Black Chrome- Ni-Cu/Steel absorber through theoretical and CFD analysis.
... Due to the increasing cost of energy, traditional dryers and drying procedures are not cost efective [4,5]. Drying has become an energy-intensive and unafordable practice for farmers due to diminishing fossil fuel supplies and rising costs [6]. ...
... Higher heat retention and low heat transfer from the outer atmosphere and vice versa should be maintained for greater efciency of the dryer. Tese factors leads us to the practical thinking of FRP-based composites as an alternative for conventional metal-based walls of the dryer cabinet due to their extensive property of heat transfer resistance between mediums [6,7]. In this research work, drying of ginger was undertaken to study and investigate the performance of the integrated composite cabinet with a solar fat plate collector. ...
... Te formulae used to calculate the wetness of ginger using the solar dryer system are tabulated in Table 2 and represented through equations (1)(2)(3)(4)(5)(6). Physical errors such as fxed errors, manufacture errors, and random errors were considered while other parametric errors such as relative humidity, moisture loss, weight loss, solar intensity, and air velocity errors were also considered during the experimental phase. ...
Generally, solar dryer cabinets are made up of sheet metals that are heavy, costly, tend to rust over time, and possess the high heat rate to the outer atmosphere. In order to overcome these drawbacks, this research urges to develop a natural fiber reinforced polymer-based cabinet dryer, specially designed and fabricated for the purpose of solar drying. Nylon is used as the matrix material and Prosopis juliflora in particulate form is used as the natural fiber reinforcement. The dryer cabinet was designed at industrial scale to dry 5 kg of ginger at a single setting. This work also studies the efficiency of the polymer composite cabinet integrated with a flat plate solar collector system that is coated with copper and black chrome attached to corrugated fins in between the absorber plate and storage medium. The FRP chamber was compartmented in its interior with aluminium perforated sheets and experimentation was performed to determine the efficiency of the composite cabinet based on reduction of heat loss from the system. The performance of the coating, storage medium materials, and overall storage efficiency were also studied. The FRP cabinet resulted in a moisture level less than 8.5% within 4–7 days. Exergy studies showed 75% efficiency and energy studies gave 25.5 kJ/kg peak readings of drying efficiency for a period ranging between 11 and 12 hours. This was a 75% increment in energy efficiency. Thermal degradation of the FRP material was found to be stable up to 300°C. The overall weight of the constructed polymer cabinet was 25% lesser than the conventional systems.
... The developed sheet metal material is focused towards applications in the construction of solar panel frames that require low cost and efficient load to strength parameters. On considering factors from various previous literature [13][14][15][16][17], such as energy level, exergy parameters, heat generated in the solar panels based on various materials and composites, concentration of solar energy over sustained duration of time and the fluctuating weather condition taken into account, this study elaborates the optimum stress and strain dynamics through simulation modelling and analysis. ...
... They are seen as one of the most promising tools for solar energy harvesting, due to their relatively low cost and simplicity. From the pioneering work of Francia [1], the concept of LFR attracted the attention of researchers worldwide: at first quite sporadically, with some detailed technical reports [2], works on the geometrical design [3][4][5][6][7][8][9][10], analysis of receivers [11,12] and studies of prototypes [13]; then with a revamped interest in the new millennium, with the proposal of the Compact LFR (CLFR) geometry [14], followed by general analyses and other configuration proposals as [15][16][17][18][19][20][21][22][23][24]. For reviews, see [25][26][27]. ...
Linear Fresnel concentrators (LFR) are widely seen by the scientific community as one of the most promising systems for the production of solar energy via thermal plants or concentrated photovoltaics. The produced energy depends on the optical efficiency of the LFR, which is mainly dictated by the geometry of the plant. For this reason, the analysis of LFR geometry and its effects on optical behavior is a crucial step in the design and optimization of a Fresnel plant. The theoretical and computational tools used to model the optics of a LFR are fundamental in research on energy production. In this review, geometrical aspects of the optics of linear Fresnel concentrators are presented, with a detailed discussion of the parameters required to define the geometry of a plant and of the main optical concepts. After an overview of the literature on the subject, the main part of the review is dedicated to summarising useful formulas and outlining general procedures for optical simulations. These include (i) a ray-tracing procedure to simulate a mirror field, and (ii) a fast quasi-analytical method useful for optimizations and on-the-fly computations.
... Secondly, the best system was tested with different reflector materials, which reached 0.98. In addition, the absorber was coated with other coating materials to find that Black Chrome-Ni-Cu/Steel absorber had the best performance among the rest [8]. Furthermore, a numerical simulation for a linear Fresnel system was carried out to investigate the thermal heat analysis for the system. ...
This study aims to utilize the reflector-sheet temperature of the secondary reflector for the Linear Fresnel Solar system, which reaches high temperatures due to the reflection and absorption of concentrated solar radiation. Furthermore, thermoelectric generator modules, also known as Seebeck generators, with a high conversion performance are implanted to utilize the lost energy in the secondary reflector and generate electricity, which usually goes to waste. In addition, two new designs of the secondary reflector were introduced: a One-Way reheating path and Two-Ways reheating path. The system's novelty is clarified by inserting thermoelectric generator modules in a linear Fresnel Solar system for the first time and pumping the working fluid in a modified secondary reflector over the thermoelectric generator module's cold-side. Therefore, the working fluid will be preheated by the cold-side of the thermoelectric generator modules in the secondary reflector before entering the absorber tube. Traditionally, the Linear Fresnel system pumps the working fluid directly to the absorber tube. The new design's results showed significant improvements over the traditional design. The increase in the solar radiation intensity increased the average temperature of the secondary reflector sheet, the thermoelectric generator modules efficiency, and the thermal efficiency by 39.5 °C, 2.4%, and 7%, respectively. In addition, increasing the diameter of the absorber tube to 18 cm increased the working fluid temperature by 9 °C and its thermal efficiency by 2.1%. But the 12 cm diameter showed an increase in the average temperature for the secondary reflector by 12 °C. In contrast, the smaller implanted area of thermoelectric generator modules had a higher working fluid temperature of 13 °C. On the other hand, the larger implanted area improved the system efficiency by 2.2%. Furthermore, the One-Way reheating path design rose the working fluid temperature in the absorber tube by 21.9 °C and the thermal efficiency by 3.3%. Nonetheless, the Two-Ways reheating path design slightly increased the thermoelectric generator module's efficiency by 0.19%.
... Presently, several plants are under development by Alba Nova in France (12 MW) [3]. Research developments are currently focusing on enhancing the energetic and exergetic efficiencies of the LFRs to reach competitiveness against other electricity production options ( [43][44][45]). In Saudi Arabia, a techno-economic study concerning the implementation of CSPs with cogeneration gas turbines was established by Mokheimer et al. [46]. ...
The use of solar powered dish-Stirling engines to convert thermal energy into electricity is a promising and renewable alternative in reducing the fossil fuel consumption. However, insufficient experimental data regarding the operating parameters limit its characterization, modelling, design, optimization, and further utilization. Therefore, the first aim of this paper is to introduce a comprehensive review and systematic summary of state of the art on research and progress of the solar dish technology as a concentrated solar power technology. The efforts mainly include the recent advances, technological challenges, and optimization frameworks in solar dish collector research field. One of the most critical features of this study is discussing novel combinations of solar dish collectors with other power generation devices including PV cells, thermoelectric devices, and thermal collectors. The review sheds light also into recent thermodynamic cycles that can be powered by solar dish collector as well potential polygeneration applications that can be engineered. Further, the most relevant researches adopting Nanofluids and Phase Change Materials in solar dish collectors are reviewed. In the final part, future prospects and challenges that require further investigation are also discussed. It is expected that this review will serve as a brief guideline for the solar dish-technology enthusiast.
... Moreover, the optimum transition point from the singletarget mirror section to alternating target mirror section must be determined based on the parameters of the field. Babu et al. (2020) compared a CLFR field with mirrors of equal width to a field of varying mirror widths, obtaining concentration ratios of C R = 103.33 and C R = 85 respectively. ...
Linear Fresnel collector plants represent a promising line-focusing concentrating solar thermal technology that has not yet reached commercial maturity. This technology has many advantages, but its core disadvantage is the low optical performance of the primary collector field. The design of the primary is therefore of vital importance to the competitiveness of the technology. The large number of independent parameters in primary collector designs has led to many different optical design methodologies and optimisation studies. This review paper firstly details the different optical loss mechanisms and their relative importance to the performance of the primary. The different models used to quantify performance are then detailed. The subsequent sections categorise the collector primary design into three broad themes: designing for peak conditions (no blocking and shading for a vertical sun); design optimisation (from sensitivity studies to particle swarm and multi-objective optimisation studies); and novel linear Fresnel layouts. Novel layouts make use of additional degrees of freedom and non-imaging optics to create hybridised collector fields with enhanced optical efficiency. While this avenue shows much promise, the cost implications of the added complexity are typically not fully quantified.
In building integrated PV/T applications, the utilization of linear Fresnel micro-concentrators could promote solar energy harvesting efficiency. For the consideration of low wind load and building aesthetics, the height of the concentrator is invariably kept in a small range, resulting in severe optical blocking between mirrors. In this paper, two offset-axis mirror models are introduced to promote the optical efficiency of the micro-concentrator. The rotating axis of the mirror in the former model is not located on the symmetrical axis of the mirror but is offset to one side of the mirror. The later model is a rod offset-axis mirror with the axis offset to the outside of the mirror by a rod. These offset-axis mirrors allow the mirrors farther away from the receiver to possess a higher position for larger angular rotation, thus reducing the blocking between mirrors. Thereafter, mathematical models were established to obtain the key parameters of each mirror at different axis positions, and the influence of the axis position on the optical performance of the micro-concentrator was analyzed. The results revealed that both kinds of offset-axis mirrors could significantly improve the ground utilization ratio of the micro-concentrator and realize a more compact micro-concentrator design. In comparison with the layout scheme with the conventional central-axis mirrors, the ground utilization ratio of micro-concentrator with a hybrid layout of side-axis mirrors and rod offset-axis mirrors was improved by 28%. The optical simulations based on the Monte Carlo method revealed that a micro-concentrator with a hybrid layout of side-axis mirrors and rod offset-axis mirrors could promote the solar harvesting efficiency by 56.8% compared to the conventional central-axis mirror layout, regardless of direct normal sunlight or large angle inclined sunlight. The concept and calculation methodology of offset-axis mirror presented in this paper could reduce the thickness of linear Fresnel micro-concentrators in the design and improve their concentrating efficiency, which would lay the solid foundation for the wide application of micro-concentrators in the building domain.
A linear Fresnel reflector concentrating solar system (LFRCS) is modeled and optimized to obtain the maximum solar energy conversion. The concentration ratio is based on the parameters considered for design. The numerical analysis is performed on the values obtained from the formulae derived from the geometrical representation, the naturally iterative formulae are solved computationally using MATLAB and then compared with the optimization tools used. The design parameters or decision variables are focal height of the absorber and diameter of absorber. The present work will help engineers reduce design time to find an optimum solution. The best optimum algorithm in PSO will give a solution that is difficult to obtain through simple modeling programs and numerical analysis. The system is designed to generate pollution free energy for the society. This research provides results on a novel Particle Swarm Optimization (PSO) aided with multitude algorithms, improvised Simple-PSO; Improvised-PSO; Modified-PSO; TACPSO (Time Varying Acceleration) and AGPSO (Autonomous Group). On optimizing the values obtained from analytical analysis, this is the first paper on a multitude of algorithms of (PSO) to find the optimum values of the parameters. The results obtained by PSO optimization techniques give the accurate values for the parameters considered on which the concentration ratio is maximum when compared with the theoretical, numerical analysis values. A detailed performance survey is analyzed for the designed system to deliver the effectiveness of the proposed methodology.
The performance of the horizontal absorber with varying width reflectors in terms of concentration ratio is analyzed analytically and are optimized using miltitude algorithms of Particle Swarm Optimization technique. The analytical and optimized values are further taken for experimental analysis which is presented in this paper. The maximum concentration is obtained when the focal height is f = 0.96 m and absorber width is d = 0.054 m. The number of reflectors is determined as d = 29 for each side of the absorber. Total number of varying width reflectors are 58 numbers, the width varying from W 1 to W 29 = 0.03 m-0.06 m and the aperture diameter is fixed as CR = 2 m. The system is modelled with the said parameters and the maximum concentration ratio is obtained by optimization technique is D = 32.6. The experimental setup was fabricated, installed and tested at Thanjavur, Tamil Nadu, India during the hottest months from March to June and readings are recorded. The data recorded are plotted and discussed. The maximum storage tank temperature varies from 35 °C to 78 °C. The outlet temperature is maximum during mid day, the temperature difference is 9 °C. The thermal efficiency of the designed LFRSC System is 41.2%.
Full text download (both in spanish and english):
www.tinyurl.com/libro-er
Using ray track technology and geometrical analysis, this paper has presented novel design method which can be applied to mirror elements of equal width and varying width, varying height of absorbers of linear Fresnel Reflector Solar Concentrators(LFRSC) whose mirror elements are north-south direction. This paper also discussed the efficiency of mirror elements, it calculated the efficiency every 5 °from 30°to 150°and the conclusions gave some parameters with reference value.
This paper describes some of the results of a recent study commissioned by the New South Wales Government on the performance of a new solar array technology called the Compact Linear Fresnel Reflector (CLFR). The performance and cost of this technology are reported for application in large-scale solar thermal electricity generation plants. Comparisons are made of the relative performance and cost compared to parabolic dish and Solel trough solar thermal technologies and future photovoltaic plants. The results suggest that the CLFR is the lowest cost option for large scale solar electricity plant in the foreseeable future.
Thermal performance of the four identical trapezoidal cavity absorbers for linear Fresnel reflecting solar device were studied and compared. The absorbers were designed for operating in conjunction with a prototype Fresnel solar reflector. Rectangular and round pipe sections were used as absorber by placing in the trapezoidal cavity. The absorber pipes were coated with ordinary dull black board paint and black nickel selective surface. The bottom of the cavity was provided with plane glass to allow the solar radiation to be reflected from the Fresnel reflector. The other three sides of the cavity absorber were insulated to reduce heat loss. Thermal performance of the Fresnel reflecting concentrator with each trapezoidal cavity absorber was studied experimentally at different concentration ratio of the reflector. The study revealed that the thermal efficiency was influenced by the concentration ratio and selective surface coating on the absorber. The thermal efficiency decreased with the increase in the concentration ratio of the Fresnel reflecting collector. The selective surface coated absorber had a significant advantage in terms of superior thermal performance as compared to ordinary black painted absorber. The round pipe (multi-tube) receiver had higher surface area to absorb solar energy as compared to rectangular pipe receiver. Thermal efficiency of the solar device with round pipe absorber was found higher (up to 8%) as compared to rectangular pipe absorber.
Electroplating selective copper oxide coatings were prepared on the surface of a rectangular absorber (α = 0.92 and ε100°C = 0.18) for operation in conjunction with a prototype linear solar Fresnel reflecting concentrating collector. Overall heat loss coefficients (UL) of the selectively coated absorber at temperatures up to ~300°C, optical efficiency (ηo) and stagnation temperature of the concentrator-absorber system were determined experimentally. The results have been compared with those obtained from an identical black painted absorber. Thermal efficiency (ηc) computed from the results of UL and ηo measurements at a temperature of 250°C provides a value of 49% with the selectively coated absorber and 48% with the black painted absorber.
The present article describes the numerical study of heat transfer analysis in a trapezoidal cavity absorber of a linear Fresnel reflector solar concentrator (LFRSC) system. The linear absorber is a part of the linear Fresnel reflector solar concentrator system, in which hot fluid is generated. The absorber is an inverted air cavity with a glass cover enclosing an absorber surface. In the present analysis, a linear multi-tube absorber with and without the absorber plate underneath is considered. The ANSYS workbench package with FLUENT 12.0 version is used to develop the two-dimensional, steady-state, and laminar-flow heat transfer model for a trapezoidal cavity absorber. The models with Boussinesq and non-Boussinesq approximations are used for the numerical analysis and the performance is compared. The heat transfer rate, radiation heat loss, and combined heat loss coefficients are predicted at various absorber surface temperatures and for the absorber surface with ordinary black paint and with selective surface coating. For validation, the present computational model is compared with the analytical values and other reported closed cavity models. A better design of the cavity absorber is found out to maximize the heat transfer rate applied to the absorber tubes for better fluid outlet temperature.
Linear Fresnel collectors are a type of concentrating solar power technology. In this paper, the technology's technical features and aspects are first described via illustrations of various design concepts; then, the past low- and intermediate-temperature applications of linear Fresnel collectors are reviewed and their state-of-the-art applications in utility-scale electricity generation are presented; finally, the performance, technical challenges, and future outlook of linear Fresnel technology in the context of utility-scale power plants are summarized.
A model residential photovoltaic system which utilizes a solar cell
array roof shingle combination is discussed in relation to developing
and generating the environmental data for decentralized solar
photovoltaic systems. Material requirements, operating residuals, land
requirements, water requirements, production processes, and production
residuals for the systems operation are examined. Environmental, health,
safety, and resource availability impacts are reported.
This paper is aimed at characterizing the concentration process for LFRs, and to analyze the use of different optical designs, including circular-cylindrical and parabolic-cylindrical mirrors with different reference positions. A new approach to analyze and optimize the performance of Fresnel arrays is presented, which is based on a newly formulated optical property that can be used to evaluate the drift of the reflected sunbeams from the mirrors as they rotate to follow the sun. This new optical-geometric property sets upper bounds for the deviation of the reflected sunbeams, in relation to trajectories of the reference situation. It is observed that the maximum deviation depends on the width of the mirror, which must be limited for maximizing the optical efficiency. From this theory an optical design process is suggested to minimize such lateral drifts and to minimize the concentration factor variation along the day. A new mirror layout is defined for keeping a constant value of the radiation impinging onto the receiver from effective sunrise to effective sunset.
The results of a study to examine the line focus central receiver alternative for solar thermal generation of electric power on a commercial scale are presented. The baseline concept consists of the following elements: (1) a solar collector (heliostat) whose geometry is the equivalent of a focused parabolic cylinder. The heliostat reflecting surface is composed of an array of flexible rectangular mirror panels supported along their long edges by a framework which rotates about an axis parallel to the ground plane. The mirror panels in one section (18.3 meters by 3.05 meters (60 feet by 10 feet)) are defocused in unison by a simple mechanism under computer control to achieve the required curvature. Two sections (110 meters²(591 feet²)) are controlled and driven in elevation by one control/drive unit. (2) A linear cavity receiver, composed of 61-meter (200-foot) sections supported by towers at an elevation of 61 meters (200 feet). Each section receives feedwater and produces turbine-rated steam. The cavity is an open cylinder 1.83 meters (6 feet) in inside diameter, with a 1.22 meter (4 foot) aperture oriented at 45 degrees to the collector field. (3) Heliostat control, consisting of a local controller at each heliostat module which communicates with a master control computer to perform elevation tracking and focal length adjustment. The control logic is open-loop, with sun position computer by the master computer with an algorithm. Image sensors, mounted above and below the receiver aperture, are used to monitor the collector field and provide feedback to the master computer for detection of misaligned heliostats. (WHK)
Emphasis was placed upon the selection and use of a model residential photovoltaic system to develop and quantify the necessary data. The model consists of a reference home located in Phoenix, AZ utilizing a unique solar cell array roof shingle combination. Silicon solar cells, rated at 13.5 percent efficiency at 28 C and 100 mW/sq cm insolation are used to generate 10 kW (peak). An all electric home is considered with lead acid battery storage, DC AC inversion and utility backup. The reference home is compared to others in regions of different insolation. It is suggested that solar cell materials production and fabrication may have the major environmental impact when comparing all facets of photovoltaic system usage. Fabrication of the various types of solar cell systems involves the need, handling, and transportation of many toxic and hazardous chemicals with attendant health and safety impacts. Increases in production of such materials as lead, antimony, sulfuric acid, copper, plastics, cadmium and gallium will be required should large scale usage of photovoltaic systems be implemented.
Optical designs and performance characteristics of a linear Fresnel reflector solar concentrator (LFRSC) with a flat vertical absorber have been presented. Two different approaches have been utilized for designing a LFRSC. One of the approaches allows a variation in the width of the constituent mirror elements, while the second approach uses mirror elements of equal width. A detailed performance analysis including the effect of variation in the height of the absorber from the concentrator plane, aperture diameter of the concentrator, width of the absorber and the width of the mirror elements on the concentration on the surface of the absorber has been made for each design. The distribution of local concentration ratio (L.C.R.) on the surface of the absorber, for each design, has been investigated using the ray trace technique. Results are plotted graphically and discussed.
A somewhat new approach to the design of solar concentrators of Fresnel reflector geometry is outlined. the constituent mirror elements of the concentrator surface are characterised by three parameters, shift, tilt and width. the evaluation of these parameters and the concentration characteristics are investigated on the basis of a simple ray optical model.
Two different approaches for designing a linear Fresnel reflector solar concentrator (LFRSC) with a flat horizontal absorber are described. The performance characteristics of both the designs are studied in detail. The distribution of local concentration ratio on the surface of the absorber, for each design, is investigated using the ray trace technique. Results of some typical numerical calculations are presented graphically and discussed.
A linear Fresnel reflector-concentrator employing commercial flat, front-reflecting mirror strips (of reflectivity [varrho] = 0·6), arranged in a planar configuration, has been fabricated and analyzed. An average concentration ratio of about 18 has been obtained for two-thirds of the periphery of a tubular receiver of 0·025 m diameter. Working in conjunction with a partially evacuated (10-2 Torr) cylindrical collector employing a selective cobalt oxide coating (with [alpha] = 0·88, [epsilon]250°C = 0·25 and stable up to 600°C), a stagnation temperature of ~ 385°C has been obtained, corresponding to a direct solar flux of ~ 600 W/m2.
Tribological test on copper based hybrid composite materials
- Sachin S Raj
- Elavarasan
- C Arundeva
- Govindarasu
- Devaraj
Optical design and concentration characteristics of linear Fresnel reflector solar concentrators - II. Mirror elements of equal width
- Mathur
Theoretical Performance Analysis of Linear Fresnel Reflector Concentrating Solar System with Horizontal Absorber
- Babu
Thermal analysis on exhaust valve with thermal barrier material
- M C Sai Prasad
- Sachin S Babu
- Raj