Concentrated Solar Beam Research Articles

Experimental study of a concentrating solar spectrum splitting system for hybrid solar energy conversion

Spectral beam-splitting represents a potential approach to enhance energy conversion in solar concentrating systems. This study introduces a novel hybrid solar concentrator system, comprising a dish reflector with a two-axis tracking system and an affordable optical linear system that divides the concentrated solar beam into distinct visible spectral bands. Experimental investigations were conducted, encompassing an optical analysis of the splitter system and an assessment of photovoltaic and thermal power generation from the prototype throughout a day with solar tracking. Results indicate that the splitter system achieved a transmissivity of 76 % within the 400–800 nm range with clear separation between spectral bands, demonstrating system reliability. Spectral band dimensions remained relatively constant throughout the day, with widths of 0.460 cm, 0.550 cm, and 0.700 cm for red, blue, and yellow bands, respectively. The photovoltaic cell exposed to the yellow band exhibited the highest power and current intensities, with power densities of 15 mW/cm2 at noon, compared to 12 mW/cm2 for the blue and 5 mW/cm2 for the red bands. The system also recovered thermal power, reaching a maximum of 190 W around noon. The paper discusses suitable photovoltaic cell types for each band color and explores opportunities for improved efficiency and large-scale implementation.

Solar-assisted approach for the synthesis of nanoadsorbents for biogas desulfurization using wastes

Minimizing food wastes and finding a second life use for industrial residuals have become some of the top priorities of modern society. This work considers the use of spent eggs and mussels shells, as well as marble dust, as raw sources to develop nanoparticles involving renewable resources in both their preparation and adoption in technological applications. Specifically, Ca/Mg-based nanoparticles were obtained by evaporating such wastes in a physical vapor deposition system using concentrated solar beam and explored as high capacity H2S adsorbents for the purification of biogas. The evaluation of their uptake performance in a fixed-bed configuration indicates that the formation of a thick layer of Ca(OH)2 on very small nanoparticles (<70 nm) inhibits H2S uptake, whereas the presence of Mg phases (dolomite) favors its potentiation. Importantly, the co-evaporation of iron provides an extra amplification of the absorption capacity due to the synergy of the Ca/Mg neutralizing character and the affinity of Fe for sulfur. In the best case, the nanoparticles obtained from mussels and 10 %wt. Fe reached an uptake capacity of 0.92 mg/g. This high yield is attributed to the formation of oxides, such as Ca2Fe2O5, that allow a sulfide to sulfate oxidation-adsorption mechanism.

A proposal for additively manufacturing printed circuits by employing concentrated solar energy

A novel method capable of generating printed circuits using concentrated solar energy (CSE) is proposed. The open literature has reported that no method employs CSE to obtain printed circuits additively. Based on the Mill & Fill method, a conductive material (Sn63Pb37) is deposited inside a trench milled on a thermoplastic substrate (PETG). The concentrated solar beam melts the conductive material to form a solid trace, while the substrate relaxes its structure and allows the inclusion of the path. The resulting hybrid joining between plastic and metal is like those obtained by LAMP (laser-assisted joining of metal-polymer). The 20 conducted tests found that the magnitude of direct solar radiation and the overall system efficiency are the most influential variables on the exposure time of the trace to the solar spot. Each test, with its conditions, was simulated in COMSOL Multiphysics software, and the temperatures obtained experimentally were compared with those obtained by simulation. This proposal is expected to serve as a bridge between both fields of study so that solar concentrators will be considered in the additive manufacturing of printed circuits and expand CSE's potential for developing consumer goods.

Experimental Study of Electric Power Generation with Concentrated Solar Thermoelectric Generator

Although thermoelectric technology is little-known in the public domain, it presents an exciting alternative solution in many cases where lost heat energy can be quickly recovered to produce electricity. In the present paper, an attempt is undertaken to exploit this energy. For this purpose, an experimental study is conducted to produce electricity with the thermoelectric effect by utilizing a device placed on a parabolic concentrator. The device is placed on a solar tracker. The results obtained for two days of two distinct months, January and June, revealed that the production in June was higher than that in January by around 92.86%. This distinction is due to the concentrated solar beam being different on a day in each month. A vital product was recorded by utilizing the concentrator. This gadget permitted us to take advantage of the limit of sun-based radiation to produce power. The power may be stored with a legitimate stockpiling procedure.

Synthesis of Non-Cubic Nitride Phases of Va-Group Metals (V, Nb, and Ta) from Metal Powders in Stream of NH3 Gas under Concentrated Solar Radiation

Using a high-flux solar furnace, loosely compacted powders of Va-group transition metal (V, Nb, and Ta) were reacted with stream of NH3 gas (uncracked NH3 gas) being heated by concentrated solar beam to a temperature (T) range between 600 and 1000 °C. From V, sub-nitride V2N (γ phase) and hypo-stoichiometric mono-nitride VN possessing fcc (face-centered cubic) crystal lattice structure (δ phase) were synthesized. On the other hand, in the reaction product from Nb and Ta, hexagonal mono-nitride phase with N/M atom ratio close to 1 (ε phase) was detected. The reaction duration was normalized to be 60 min. In a conventional industrial or laboratory electric furnace, the synthesis of mono-nitride phase with high degree of crystallinity that yield sharp XRD peaks for Va-group metal might take a quite long duration even at T exceeding 1000 °C. In contrast, mono–nitride phase MN of Va-group metal was synthesized for a relatively short duration of 60 min at T lower than 1000 °C being co-existed with lower nitride phases.

The experi̇mental thermal analysis of aluminum metal melting with concentrated solar energy

The concentrated solar energy which is one of the renewable energy sources, is examined in metal melting which requires high temperatures. The study is carried out for the first time in an environment where total solar radiation of 1394 kWh m−2-year and sunshine duration of 2132 h-year at the sea level in Trabzon province at 41° latitudes and 39° longitudes. In the present work, a single concentrator model of solar furnace system is presented. Parabolic dish with a diameter of 1.42 m was used for the first time with high reflection rate chromium nickel foil in the concentration of the solar rays. To store the concentrated solar beams, a metal melting furnace is designed, manufactured and tested. Total heat loss analysis of the furnace according to measured experimental values is performed for the designed solar furnace. The melting process of the aluminum metal was realized in the furnace. In the experiment, the efficiency of the system was calculated based on the measured temperatures and solar radiations. The system efficiency which consists of the parabolic solar concentrator and the solar furnace was found to be approximately 46% at the average focal temperature of 1023 K. In the melting process, the efficiency of the furnace is calculated as the ratio of stored energy to the absorbed solar energy on the surface. The total thermal efficiency 22% is calculated for the first time in the aluminum melting process and mass flow rate is 0,0667 g s−1 at this time.

Glass melting using concentrated solar thermal energy

Glass melting using concentrated solar thermal radiation is demonstrated on the kilogramme scale using a high flux solar simulator (HFSS). The melting process involved a novel furnace design utilising a downward orientated concentrated solar beam coupled with back-up integrated electrical heating elements, which provided secondary heating to maintain a melt when the HFSS beam was unavailable (i.e. equivalent to cloudy conditions or at night). With 5·26 kW radiative power from the HFSS input to the furnace through a 6 cm diameter aperture, pelleted soda–lime–silica batches were melted. Repeated additions of ∼300 g of batch pellets were made to the melt with each ∼300 g addition requiring ∼15 min for the reactions to complete and the melt temperature to recover. This is equivalent to a glass batch melting thermal efficiency of 16% at a solar concentration ratio of 1857 suns. The areas of land required for the heliostat field and, for the electrical backup elements, photovoltaic field are shown to be significant for even moderate daily glass production tonnages.

Reactions of IVa-group metals, Ti and Zr, with uncracked NH3 gas at a temperature in the range between 600 and 800 °C under heating with concentrated solar beam at PSA

Low-temperature (600–800°C) short-time (30–90min) nitriding of IVa-group transition metals, Ti and Zr, in flow of NH3 gas (uncracked ammonia) was carried out under heating with concentrated solar beam in the vertical type SF5 solar furnace at PSA (Plataforma Solar de Almería) in Tabernas, Spain. Due to low nitriding temperature and short reaction duration, full conversion of starting metallic material to nitride was not realized as a matter of course. Nevertheless, detectable extent of nitriding appeared to have progressed for both metallic Ti and Zr at the reaction temperature higher than 700°C to yield mono-nitride MN possessing face centred cubic (fcc) lattice co-existed with M solid-solutioned with N possessing hexagonal closed packed (hcp) lattice. Such partially nitrided powders might be accepted as convenient starting material for combustion synthesis (CS) of near net shape component of nitride ceramics.

Low-temperature short-time nitriding of Va-group metals, V, Nb and Ta, in uncracked NH3 gas under heating with concentrated solar power (CSP)

Over the last two decades, the authors have been using concentrated solar beam as the reaction heat source for synthesizing carbides and nitrides of d-group transition elements in view of usage of ecological renewable energy source in place of conventional heat sources using electricity or natural gas. In recent works, nitriding of VIa-group metals (Cr, Mo, W) and Fe in stream of NH3 gas with suppressed extent of dissociation (uncracked NH3) was attempted under heating with concentrated solar beam. It was demonstrated that mono-nitride δ-MoN of Mo and sub-nitride ɛ-Fe2N of Fe that are known to be impossible to synthesize in N2 gas environment even at elevated N2 gas partial pressure p(N2) up to 300bar were successfully synthesized by the reactions of these metals in stream of NH3 gas under heating with concentrated solar beam up to 800°C.In the present work, nitriding of Va-group metals (V, Nb and Ta) was attempted in stream of NH3 gas under irradiation of concentrated solar beam. After 90min heating in uncracked NH3 under concentrated solar beam up to 800°C, X-ray diffraction (XRD) characterization of the reaction products showed certain extent of nitriding progressed for all the specimens in spite of relatively low reaction temperature for short reaction duration.

Heat transfer in directly irradiated fluidized beds

Directly-irradiated fluidized bed solar reactors are very promising in the context of solar chemistry and concentrated solar power (CSP) applications. With proper choice of the bed solids, fluidized bed reactors can be operated at fairly high process temperatures that enable thermochemical storage with high energy density and production of solar chemicals and fuels. Bed surface overheating upon irradiation is one key to the efficiency of the fluidized bed as thermal receiver and may be responsible for sintering and/or degradation of the fluidized particles. Tailoring the hydrodynamics of the bed close to the region where the incident power is concentrated may disclose effective measures to improve the interaction between the incident radiative flux and the bed and mitigate bed surface overheating.In the present study radiative heat transfer from a concentrated simulated solar radiation source to a fluidized bed is investigated by time-resolved infrared mapping of the bed surface temperature. A fluidized bed of silicon carbide particles (0.127mm), whose cross-sectional area is 0.78×0.78m, was directly irradiated by highly concentrated simulated solar radiation, emitted by a 4kWel short-arc Xe lamp coupled with an elliptical reflector. The experimental apparatus is also equipped with a movable nozzle coupled with a bubble generation system located coaxially to the concentrated simulated solar beam. The interaction of the concentrated radiative flux with the fluidized particles moving under the action of bubble bursting was assessed by characterizing the time-resolved bed surface temperature as the fluidization gas velocity was varied. The effect of localized generation of bubbles was also investigated by injecting chains of multiple bubbles from the nozzle located at variable distance from the bed surface.

Electrophysical and optical properties of silicon produced by multiple remelting of metallurgical silicon by concentrated solar beams (Review)

The review describes a new method for refining silicon—multiple melting of industrial silicon in open air in a solar furnace. The results of three-, five- and eightfold refining are given. In all cases, a sample of melted silicon with simple ohmic contacts during heating at T > 30°C becomes a current and voltage generator, which is explained by the processes of self-organization of deep-lying impurities, leading to their periodic distribution along the sample. From such silicon, p–n transfer is obtained, which opens possibilities for practical application.

Internally-circulating Fluidized Bed Reactor Using Thermal Storage Material for Solar Coal Coke Gasification

Abstract A windowedreactor prototype of internally-circulating fluidized bed is tested and demonstrated at laboratory scale for steam gasification of coal cokeirradiated directly by concentrated Xe light from a 3-kW th sun simulator.The bed material is composed of particle mixture of coal coke and quartz sand. A coal coke of the bed material works as a carbonous feedstock, while quartz sand functions as a thermal storage/transfer medium inside the reactor. The fluidized bed reactor, having a transparent window due to incoming radiation of concentrated solar beam on the ceiling of the reactor, is designed to be combined with a solar reflective tower or beam-down optics.A potential of quartz sand in the internally-circulating fluidized bed reactor is evaluated forsteam gasification of coal coke by gasification performance (CO, H 2 and CO 2 production rates, carbon conversion, and light-to-chemical efficiency). The gasification performances for use of the particle mixture in the reactor are compared with that for use of coal coke particle.The fluidized bed of a particle mixtureincluding coal coke and quartz sand was gasified at lower temperature with a higher rate in comparison to that of a coal coke.Furthermore, a use of smaller and lighter coal coke particles were easily converted to gaseous species due to larger surface area as well as the gasification rates.

Nitriding VI-group metals (Cr, Mo and W) in stream of NH3 gas under concentrated solar irradiation in a solar furnace at PSA (Plataforma Solar de Almería)

Carbides and nitrides of d-group transition metals are classified as refractory hard material and their industrial importance has been recognized for long. In recent years, unique functionalities including catalytic function and superconductivity are discovered for this group of materials to raise serious attention of materials researchers and engineers to refractory carbides and nitrides as novel functional materials.Synthesis of refractory carbides and nitrides demands high temperature reaction route to consume considerable amount of electricity or gas in conventional industrial process. In view of saving cost of such conventional energy, feasibility of using concentrated solar beam as heat source for synthesizing carbide and nitride has been investigated by the authors since 1997. After verifying usefulness of concentrated solar beam as heat source for carbide forming reactions, similar attempts of employing concentrated solar beam as heat source for nitride synthesis were initiated recently. After brief experimental verification of nitride synthesis for IVa group metal, Ti, and Vg group metals, V, Nb and Ta, in N2 gas environment under irradiation with concentrated solar beam to 2000°C, the authors decided to undertake nitride synthesis of VIa group metals, Cr, Mo and W, as well as of Fe in stream of ammonia (NH3) gas as a nitriding medium under irradiation of concentrated solar beam at temperatures not exceeding 1000°C.NH3 gas with suppressed extent of dissociation by flowing is defined empirically as uncracked NH3 and it is proved to possess very high nitriding power to make synthesis of mono-nitride MoN of Mo coexisting with sub-nitride Mo and higher nitride Fe2N of Fe possible under normal pressure condition that are not possible when chemically stable N2 gas is used as a nitriding agent.VIa-group metals including Cr, Mo and W are known to be highly resistant against nitriding. In the present report, results of nitriding in flowing NH3 gas at a fixed flow rate 10l/h (≈167ml/min) under heating with concentrated solar beam for VIa-group metals, Cr, Mo and W, are summarized to demonstrate favorable effect of solar beam heating towards further enhancement of nitriding power of flowing NH3 gas compared with the situation in conventional electric furnace in which visible light components except infra-red (IR) heat wave component are absent in the reaction system.

Roles of Unstable Chemical Species and Non-Equilibrium Reaction Routes on Properties of Reaction Product—A Review

Chemical species might be held in a state being away from equilibrium state, at least temporarily, as represented by non-graphitic carbon and gaseous ammonia NH3 with suppressed extent of dissociation by flowing. Such chemical species X in unstable state would possess chemical activity a X considerably higher than that of the same element in equilibrium (reference) state. In case of carbon, a C of amorphous carbon is higher than that of graphite (equilibrium state of C; a C = 1). Thus, when metal M is reacted with excess C, carbon content x ′ in carbide MCx′ in equilibrium with amorphous carbon becomes higher than x in MCx in equilibrium with graphite. In case of uranium carbo-nitride UCxN1−x in equilibrium with excess free C under given conditions of temperature T and N2 gas partial pressure p(N2 , x ′ in UCx′N1−x′ in equilibrium with amorphous carbon was experimentally demonstrated to be higher than x in UCxN1−x in equilibrium with graphite. Gaseous ammonia NH3 with suppressed extent of dissociation by flowing would yield very high nitrogen activity a N and modestly high hydrogen activity a H while NH3 dissociated to N2 and H2 to reach equilibrium state in closed reaction chamber would yield a N and a H to be represented by respective partial pressures, p(N2 1/2 and p(H2 1/2, in the gas phase. Synthesis of mono-nitride MoN of Mo in N2 gas was reported to be impossible even at high pressure up to 300 atm in autoclave but MoN co-existing with sub-nitride Mo2N might be synthesized in flowing NH3 gas at normal pressure. As such, unstable chemical species might allow us to synthesize novel reaction product that cannot be prepared by using stable chemical species alone in the reactant. However, special care must be taken in usage of unstable chemical species. For example, in case of non-graphitic carbon, graphitization might proceed with considerably fast rate when the reaction temperature is set to be well above 2000 K and thence no effect of high a(C) might be gained at reaction temperature exceeding 2000 K. On the other hand, in case of flowing NH3 gas, extent of dissociation of NH3 gas would depend on the position along the flow path of NH3 gas stream (i.e., tends to rise inevitably on going from the up-stream side to the down-stream side) as well as on the NH3 gas flow rate (i.e., at specific position in the flow path tends to rise with diminishing NH3 gas flow rate). On the other hand, rapid solidification processing with cooling rate reaching to 106 K/s has been employed for refinement of microstructure of alloys and for extension of solubility limit as well as for formation of amorphous phases. Rapid solidification is considered as ultra-fast quenching process of high temperature micro structure, or more precisely, retention of atomistic configuration in molten state of multi-component system through extraction of heat with very high rate to inhibit atom diffusion processes to reach inherent equilibrium state defined uniquely as functions of temperature T and alloy composition. On the other hand, under certain mode of operation of solar furnace using concentrated solar beam as the reaction heat source, rapid heating to reach reaction temperature around 2000 K from ambient temperature within order of a second or even less is realized. During carbide synthesis from tungsten (W ) under such operation mode of solar furnace, the authors detected evidence of formation of WmCn phases that did not correspond to the phase anticipated by referring to available equilibrium binary W–C phase diagram at the processing temperature. This experimental evidence is tentatively appreciated in terms of small energetic differences among WmCn phases with varying m/n ratios. That is, once certain WmCn phase is formed during rapid heating of W/C powder mixture, the formed phase would remain stable at the processing temperature T even if it is not the genuine equilibrium phase at T without being transformed to the genuine equilibrium phase at the specified T due to smallness of driving force for the phase transformation

O2-releasing reactivity of ceria-based reactive ceramics on irradiation of artificial concentrated solar beam for solar hydrogen production

In the present paper, different types of metal doped ceria CeO2–MOx (M = Sc, Y, Dy, Zr and Hf) with fluorite structure have been prepared with a complex polymerization method. The O2-releasing potential of prepared samples was evaluated at 1500 °C for a two-step water splitting process. The partially oxygen defected CeO2–MO1.5 (M = Sc3+, Y3+ or Dy3+) mixed oxide exhibited an enhancement of the O2 evolution on CeO2–ScO1.5 owing to the crystal-chemical effect that cation with smaller ionic radius (Sc3+) compensates the volume expansion of crystal lattice resulted in the reduction of Ce4+ with smaller ionic radius into Ce3+ with larger ionic radius. The CeO2–MO2 (M = Zr4+ and Hf4+) produced larger amount of O2 than that for CeO2–MO1.5 mixed oxides, since CeO2–MO2 has no oxygen vacancy initially. While the ionic radii of Zr4+ and Hf4+ are almost equal, the higher O2-releasing reactivity of Ce0.9Hf0.1O2 than that of Ce0.9Zr0.1O2 is explained in terms of ionicity of M–O bond. Also, the weight losses of CeO2, Ce0.9Zr0.1O2 and Ce0.9Hf0.1O2 in the mitigation process from high PO2 (O2 gas stream) to low PO2 (Ar gas stream) atmosphere were determined. The quasi activation energies in the initial period of the O2-release for CeO2, Ce0.9Zr0.1O2 and Ce0.9Hf0.1O2 were evaluated 105, 84.2 and 75.0 kJ/mol, respectively. The O2-releasing reactivity is considered from the standpoint of an activation energy.

Experimental investigation on paraboloid solar concentrator with a conical secondary concentrator

Material removal through ablation caused by concentrated solar thermal power is investigated. Experiments are conducted using a mirror-finish electroplated paraboloid along with a conical secondary concentrator in both fall and summer months in Al Ain city, UAE. Data collection for melting of aluminum shims facilitated the assessment of the feasibility of utilizing the available solar irradiance after the two-stage concentration. A geometric concentration factor of over 2800 is achieved for the first stage of power concentration with the current installation that also has a two-axis sun tracking system and a built-in pyrheliometer. The results confirm the feasibility of the approach, as the available power for ablation around solar noon is order of magnitudes higher than the power needed for the task, for the aluminum shim used. The main aim of the study is to hone the process to the power and precision of continuous pulse laser material removal, notably CO2 lasers, as challenges further reduction of the concentrated solar beams to acceptable tolerances remain to be successfully resolved. Copyright © 2014 John Wiley & Sons, Ltd.

Synthesizing higher nitride of molybdenum (Mo) and iron (Fe) in ammonia (NH3) gas stream under irradiation of concentrated solar beam in a solar furnace

AbstractFlowing gaseous ammonia NH3 with suppressed extent of dissociation (un‐cracked NH3) is acknowledged to function as a powerful nitriding medium to realize formation of metal nitride MNx with considerably high N/M ratio x that cannot be achieved through reaction of M with N2 gas. For example, mono‐nitride δ‐MoN of Mo and ε‐FeNx phase of Fe with x = 0.33 ˜ 0.50 (i. e. hypo‐stoichiometric sub‐nitride ε‐Fe2N) were reported to be difficult to prepare in N2 gas environment even at elevated pressure but might be synthesized in flowing NH3 gas at normal pressure when reaction temperature and NH3 gas flow rate were set adequately. In the present work, nitriding experiments for Mo and Fe were carried out in flowing NH3 gas under irradiation with concentrated solar beam. The acquired experimental evidences demonstrated that temperature range for formation of δ‐MoN was somewhat extended in flowing NH3 gas under heating with concentrated solar beam compared with that under heating in conventional laboratory or industrial electric furnace. On the other hand, no such merit of extending temperature range for formation of ε‐Fe2N in flowing NH3 gas was detected in the present work under heating with concentrated solar beam.

Simulation and experimental study on a spiral solid particle solar receiver

A solid-particle solar receiver was proposed to convert concentrated solar beams into heat for high-temperature thermal storage in a two-stage dish system. Spherical Xe-arc lamps were used to simulate a solar light source. The performances of this receiver under a Xe-arc lamp array system were experimentally and numerically investigated. For a single pass, the temperature increase exceeded 350°C, and the optical efficiency and thermal efficiency were ∼84% and 60%, respectively, when the average flux on the aperture was ∼19.3kW/m2. A Monte-Carlo ray-tracing method was used to simulate concentrating beams, which was integrated with a thermal conversion model. The coupled model was validated under low radiation flux conditions and then used to predict the solid-particle receiver performance under high radiation flux conditions. The simulation results indicate that the final temperature of the single-pass particles would increase to over 1100°C under an average flux of 150kW/m2. In addition, the efficiency of the receiver could be enhanced by reducing the radiative emission.

ChemInform Abstract: New High‐Temperature Pb‐Catalyzed Synthesis of Inorganic Nanotubes.

AbstractMoS2, MoSe2, WS2, and WSe2 nanotubes are prepared by irradiation of 1:1 molar mixtures of MoS2, MoSe2, WS2, or WSe2 and Pb/PbO with highly concentrated solar beam radiation and exposure times of 30—1200 s.

Effects of Colour-filtering Solar Beam on Reaction Product Fromd-group Transition Metals in N&lt;SUB&gt;2&lt;/SUB&gt;Gas Environment under Heating with Concentrated Solar Beam

Recently, Noda and collaborators at Kyoto University reported possible enhancement of photo-voltaic cell (PVC) energy conversion efficiency by allowing penetration of preferential range of wavelength components alone to PVC by filtering the solar beam through a special semiconductor thin film developed at their laboratory. During the course of our recent experimental attempts ofnitriding<i>d</i>-group transition metals in N<SUB>2</SUB> gas environment, we detected intriguing effects of colour-filtering on reaction product. In the present report, these effects of colour-filtering are reviewed under new light of recently reported evidence by Noda and co-workers. It appears that, by colour-filtering the selected wavelength range in solar beam, undesirable secondary reactions might be suppressed to result in promotion of a target reaction under heating using concentrated solar beam as the source of reaction heat.