Transformation Of Solar Energy Research Articles

Module greenhouse with high efficiency of transformation of solar energy, utilizing active and passive glass optical rasters

Since the eighties of the 20th century, various types of linear glass rasters for architectural usage have been developed in the Czech Republic made by the continuous melting technology. The development was focused on two main groups of rasters – active rasters with linear Fresnel lenses in fixed installation and with movable photo-thermal and/or photo-thermal/photo-voltaic absorbers. The second group are passive rasters based on total reflection of rays on an optical prism. During the last years we have been working on their standardization, exact measuring of their optical and thermal-technical characteristics and on creation of a final product that could be applied in solar architecture. With the project supported by the Ministry of Environment of the Czech Republic we were able to build an experimental greenhouse using these active and passive optical glass rasters. The project followed the growing number of technical objectives. The concept of the greenhouse consisted of interdependence construction – structural design of the greenhouse with its technological equipment securing the required temperature and humidity conditions in the interior of the greenhouse. This article aims to show the merits of the proposed scheme and presents the results of the mathematical model in the TRNSYS environment through which we could predict the future energy balance carried out similar works, thus optimizing the investment and operating costs. In this article description of various technology applications for passive and active utilization of solar radiation is presented, as well as some results of short-term and long-term experiments, including evaluation of 1-year operation of the greenhouse from the energy and interior temperature viewpoints. A comparison of the calculated energy flows in the greenhouse to real measured values, for verification of the installed model is also involved.

Features of working process in stirling engines with direct and reverse cycles

The features of processes in thermodynamic transformers operating with direct and reverse Stirling cycles are considered. It is shown that nonstationarity of the heat exchange and gas dynamic processes influences the cycle efficiency. The influence of nonuniformity of solar radiant flux input to the heat absorber of the Stirling engine on solar energy transformation efficiency is evaluated.

The Transformation and Storage of Solar Energy: Progress Towards Visible-Light Induced Water Splitting

The sun is a plentiful source of clean, renewable power, and the direct conversion of solar to chemical energy is a desirable goal. The collective efforts of the Bernhard group to develop molecular catalytic systems for visible-light water splitting are reviewed. Combinatorial synthesis and high-throughput screening techniques enabled the development of a series of photosensitizers with a wide range of photophysical and electrochemical properties. Parallel evaluation of the iridium(III) photosensitizers in photocatalytic water reduction systems utilizing cobalt-, platinum-, or rhodium-based water reduction catalysts resulted in systems that exhibited more than 5000 turnovers with quantum yields of 34% and turnover frequencies of 500 hr?1. For the complementary water oxidation system, the catalysts based on cyclometallated iridium complexes are robust and tunable, which allows for the rapid study of water oxidation reactions through targeted ligand modification.

Fabrication of pure ZnO nanoparticles by polymerization method

ZnO nanoparticles have received enormous attention due to their wide range of application such as diodes, ultraviolet-protection films, catalysts, sensors, ceramics and solar energy transformation parts. In the current research, ZnO nanoparticles were prepared by polymer decomposition. Synthesized ZnO nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transition electron microscopy (TEM) and size distribution of these particles was investigated. Narrow size distribution of particles with a diameter of 20–30 nm and the regular distribution of ZnO nanoparticles were attributed to the application of poly amidoxime polymer. The results show that the polymer thermal decomposition technique is a feasible method for production of ZnO nanoparticles.

The influence of soil fertilization and maintenance upon the energy consumption requested by grapes production.

Transformation of solar energy into chemical energy by means of vegetal organisms has always represented one of the most important preoccupations of the contemporary world. The possibility to rise the light energy conversion coefficient into chemical energy depends on plant endogenous factors, represented by plant genetic abilities to biochemically assimilate CO2 as complex organic compounds using solar energy , on the one hand, and on exogenous factors as well (light, temperature, air CO2 content, humidity, soil mineral substances supply required by plant nutrition). The bioenergetical interpretation concerning the effect of fertilizers used in plant cultivation refers to a survey that studies the fossil energy consumption required by getting and applying chemical or natural organic fertilizers, on the one hand, and to the light energy stored in the main product which represents an extra cropping as a result of fertilization (Gh. Lixandru & Colab, 1980).

Energy from photobioreactors: Bioencapsulation of photosynthetically active molecules, organelles, and whole cells within biologically inert matrices

Abstract Photosynthesis is a highly efficient solar energy transformation process. Exploiting this natural phenomenon is one way to overcome the shortage in the Earth’s fuel resources. This review summarizes the work carried out in the field of photobioreactor design via the immobilization of photosynthetically active matter within biologically inert matrices and the potential biotechnological applications of the obtained hybrid materials within the domain of solar energy to chemical energy transformation. The first part deals with the design of artificial photosynthetic reaction centers (RCs) by the encapsulation of pigments, proteins, and complexes. The action of thylakoids, chloroplasts, and whole plant cells, immobilized in biocompatible supports, in the conversion of CO2 into chemical energy, is also addressed. Finally, the latest advances in the exploitation of the bioactivity of photosynthetically active micro-organisms are explored in terms of the production of secondary metabolites and hydrogen.

Новый способ преобразования энергии солнечного излучения в электричество для энергоснабжения космических станций

Новый способ преобразования энергии солнечного излучения в электричество для энергоснабжения космических станций

Thermodynamic Limits in Applications of Energy of Solar Radiation

This work analyzes contemporary trends in thermodynamics of energy generators, heat pumps, separators, and other practical devices that are driven by thermal and solar energy. We focus on applications in which the optimal control theory plays an essential role. We consider devices of engine type (generators) and of heat pump or separator type (consumers), each driven either by radiative heat or by exchanged energy or mass. We outline difficulties in defining energy limits for transformation or consumption of solar energy. We also stress their links with classical problem of maximum work and exergy analysis of thermal systems.

Modeling and Calibration of a Multi-Spectral Imaging Sensor for In-Field Crop Nitrogen Assessment

Assessment of nitrogen content from crop leaves has been of interest worldwide to help growers adjust N fertilizer rates to meet the demands of the crop. A multi-spectral imaging system was developed for in-field real-time assessment of plant nitrogen stress in corn (Zea mays L.) crops indicated by plant reflectance and measured using a vision-based multi-spectral imaging sensor (MSIS). The objectives of this article were to formulate a mathematical model of reflectance and calibrate the MSIS system. A MSIS response model was formulated based on solar energy transformation. The MSIS was calibrated with a known reflectance target to determine the relationship between the MSIS reflectance response and that of a known target reflectance by setting the MSIS, a sensor for ambient illumination (AI), and an absolute reflectance panel normal to the solar position. Sensor calibration proved the validity of the reflectance model such that dynamic adjustment of the camera parameters according to gain change maintained the linearity of log response of the MSIS. Calibration constants were determined and validated with reflectance responses of four MSIS units paired with AI sensors. Consistent performance was achieved across the units. The difference found in some units was mainly caused by erroneous AI calibration values. Corrected AI sensors improved the MSIS responses by producing nearly identical responses over all units except one unit with image formation problems.

Comparing indoor wastewater-fed aquaculture with two conventional wastewater treatment plants using adopted sustainable process indices

Highly aggregating 'Sustainable Process Indices' (SPI) were calculated for an indoor wastewater-fed aquaculture and two conventional wastewater treatment plants to make a direct comparison between the three facilities possible. The goal was to find out which technology would be better suited for use in a sustainable economy. The SPI provides a type of 'ecological footprint' for the three facilities on the basis that, in a sustainable economy, solar energy would be our main energy source and that surface area would become the limiting factor for economic development, because the transformation of solar energy into other forms of energy, products or services requires area. SPI calculations consider the area necessary for the sustainable dissipation of byproducts and wastes of a process into the environment. The SPI thus uses area as its basic unit for comparisons between different technologies, products or services. Energy consumption, as well as treatment performance (both the quality and quantity of treated effluent), and multi-functionality of facilities were key variables in determining how much area a wastwater treatment plant would need to be embedded sustainably into the environment. The calculated SPIs reveal that the wastewater-fed aquaculture requires the least area to be embedded sustainably into the environment, therefore, it would be better suited for use in a sustainable economy compared to the two conventional wastewater treatment plants.

Magnetosheath Interaction with the High Latitude Magnetopause

We present both statistical and case studies of magnetosheath interaction with the high-latitude magnetopause on the basis of Interball-1 and other ISTP spacecraft data. We discuss those data along with recently published results on the topology of cusp-magnetosheath transition and the roles of nonlinear disturbances in mass and energy transfer across the high-latitude magnetopause. For sunward dipole tilts, a cusp throat is magnetically open for direct interaction with the incident flow that results in the creation of a turbulent boundary layer (TBL) over an indented magnetopause and downstream of the cusp. For antisunward tilts, the cusp throat is closed by a smooth magnetopause; demagnetized ‘plasma balls’ (with scale ∼ few RE, an occurrence rate of ∼25% and trapped energetic particles) present a major magnetosheath plasma channel just inside the cusp. The flow interacts with the ‘plasma balls’ via reflected waves, which trigger a chaotization of up to 40% of the upstream kinetic energy. These waves propagate upstream of the TBL and initiate amplification of the existing magnetosheath waves and their cascade-like decays during downstream passage throughout the TBL. The most striking feature of the nonlinear interaction is the appearance of magnetosonic jets, accelerated up to an Alfvenic Mach number of 3. The characteristic impulsive local momentum loss is followed by decelerated Alfvenic flows and modulated by the TBL waves; momentum balance is conserved only on time scales of the Alfvenic flows (1/fA ∼12 min). Wave trains at fA∼1.3 mHz are capable of synchronizing interactions throughout the outer and inner boundary layers. The sonic/Alfvenic flows, bounded by current sheets, control the TBL spectral shape and result in non-Gaussian statistical characteristics of the disturbances, indicating the fluctuation intermittency. We suggest that the multi-scale TBL processes play at least a comparable role to that of macro-reconnection (remote from or in the cusp) in solar wind energy transformation and population of the magnetosphere by the magnetosheath plasma. Secondary micro-reconnection constitutes a necessary chain at the small-scale (∼ion gyroradius) edge of the TBL cascades. The thick TBL transforms the flow energy, including deceleration and heating of the flow in the open throat, ‘plasma ball’ and the region downstream of the cusp.

Nonlinear energy dependence of the forbidden energy band in the solid solutions CuxAg1−xBIIIC2VI

The solid solutions CuxAg1−xGaS2 and CuxAg1−xInSe2 for x = 0.5 and their terminal compounds (x = 0; 1) have been investigated both theoretically and experimentally using x-ray emission and absorption spectroscopy. These solid solutions are advanced materials for the transformation of solar energy. The electron structure of these solutions and compounds was investigated using FEFF8 code. The calculated local densities of electron states and x-ray absorption spectra were compared with our experimental x-ray spectra and photoelectron curves taken from the literature. The good correspondence of the theory to the experiment guarantees the assumed interpretation of the results for the solid solutions CuxAg1−xGaS2 and CuxAg1−xInSe2. It was found that in these solid solutions “pushing apart” of d-states of Cu and Ag takes place, which can be explained by the splitting of p-states of the atoms CVI and d-states of AI-atom (Cu and Ag). Our calculations have proved and explained the nonlinear dependence of the energy gap Eg on x.

Playing with dye molecules at the inner and outer surface of zeolite L

Plants are masters of transforming sunlight into chemical energy. In the ingenious antenna system of the leaf, the energy of the sunlight is transported by chlorophyll molecules for the purpose of energy transformation. We have succeeded in reproducing a similar light transport in an artificial system on a nano scale. In this artificial system, zeolite L cylinders adopt the antenna function. The light transport is made possible by specifically organized dye molecules, which mimic the natural function of chlorophyll. Zeolites are crystalline materials with different cavity structures. Some of them occur in nature as a component of the soil. We are using zeolite L crystals of cylindrical morphology which consist of a continuous one-dimensional tube system and we have succeeded in filling each individual tube with chains of joined but noninteracting dye molecules. Light shining on the cylinder is first absorbed and the energy is then transported by the dye molecules inside the tubes to the cylinder ends. We expect that our system can contribute to a better understanding of the important light harvesting process which plants use for the photochemical transformation and storage of solar energy. We have synthesized nanocrystalline zeolite L cylinders ranging in length from 300 to 3000 nm. A cylinder of 800 nm diameter, e.g. consists of about 150 000 parallel tubes. Single red emitting dye molecules (oxonine) were put at each end of the tubes filled with a green emitting dye (pyronine). This arrangement made the experimental proof of efficient light transport possible. Light of appropriate wavelength shining on the cylinder is only absorbed by the pyronine and the energy moves along these molecules until it reaches the oxonine. The oxonine absorbs the energy by a radiationless energy transfer process, but it is not able to send it back to the pyronine. Instead it emits the energy in the form of red light. The artificial light harvesting system makes it possible to realize a device in which different dye molecules inside the tubes are arranged in such a way that the whole visible spectrum can be used by conducting light from blue to green to red without significant loss. Such a material could conceivably be used in a dye laser of extremely small size. The light harvesting nanocrystals are also investigated as probes in near-field microscopy, as materials for new imaging techniques and as luminescent probes in biological systems. The extremely fast energy migration, the pronounced anisotropy, the geometrical constraints and the high concentration of monomers which can be realized, have great potential in leading to new photophysical phenomena. Attempts are being made to use the efficient zeolite-based light harvesting system for the development of a new type of thin-layer solar cell in which the absorption of light and the creation of an electron-hole pair are spatially separated as in the natural antenna system of green plants. Synthesis, characterization and applications of an artificial antenna for light harvesting within a certain volume and transport of the electronic excitation energy to a specific place of molecular dimension has been the target of research in many laboratories in which different approaches have been followed. To our knowledge, the system developed by us is the first artificial antenna which works well enough to deserve this name. Many other highly organized dye–zeolite materials of this type can be prepared by similar methods and are expected to show a wide variety of remarkable properties. The largely improved chemical and photochemical stability of dye molecules inserted in an appropriate zeolite framework allows us to work with dyes which otherwise would be considered uninteresting because of their lack of stability. We have developed two methods for preparing well-defined dye–zeolite materials, one of them working at the solid–liquid and the other at the solid–gas interface. Different approaches for preparing similar materials are in situ synthesis (ship in a bottle) or different types of crystallization inclusion synthesis.

CATALYST APPLICATION IN SOLAR THERMOCHEMISTRY

In this report, a comprehensive survey on the current state of catalyst applications in the field of solar energy transformation and storage is presented. Corresponding catalyzed solar chemical processes include the pyrolysis of carbonaceous compounds for the production of hydrogen, the production of filamentous carbon as well as the synthesis of unsaturated hydrocarbon compounds by rapid direct heating of methane and quenching of the reaction products.

Bioelectrosynthesis as an alternative to photosynthesis

The CO2 reduction processes have been discussed as a way of designing an ecologically totally closed technology. An electric current and molecular hydrogen are the two related available agents that can be discussed as ecologically pure reductants. The most important products are liquid and gaseous fuels, the products of large-scale organic synthesis, monomers, and amino acids. For CO2 reduction, the necessary energy consumption and H2 costs were calculated. For complex organic molecules, amino acids for instance, the energy consumption does not make up the main portion of the costs. The biocatalytic systems of CO2 reduction based on cryoimmobilized cells are described. Conversion of CO2 into L-lysine with electrochemical decomposition of water was effected on the laboratory scale. A general unit for diverse technological processes can be a bioelectrosynthetic Index Entries: Bioelectrosynthesis; CO2 reduction; liquid fuels; amino acids; immobilized cells; economic estimates. modulus, an electrochemical hydrogen generator coupled with a biocatalytic converter of hydrogen and oxygen. The systems for bioelectrosynthesis of motor fuels and essential amino acids have been economically estimated and characterized. The possibilities of combining the solar energy transformation and H2–CO2 conversion have been discussed.

On the possibility of the transformation of solar energy to chemical energy in the electrochemical cell with photoanode CdSe/TiO 2

The possibilities of the transformation of solar energy to chemical energy in the photoelectrochemical cell with CdSe/TiO 2 photoanodes and water solution electrolysis of 0.5 M Na 2SO 4 have been determined. It has been shown that the protective film of TiO 2 considerably inhibits the photocorrosion of CdSe in water electrolysis. Unlike the CdSe in the heterosystem CdSe/TiO 2, the anodic photocurrent mainly brings about water oxidation with oxygen extraction.

Hydrogen-oxidizing bacteria for biomass production

The conversion of molecular hydrogen into microbial biomass using hydrogen-oxidizing bacteria, cultivated in the presence of mineral nutrients and H 2 + CO 2 as energy and carbon source, has been examined. The transformation of solar energy into electric power by a photovoltaic device and the production of molecular hydrogen from water by electrolysis was considered. The technical recovery of the process should attain 0.02, which gains over the photosynthetic efficiency expressed by the more valuable plants in the better environmental conditions.

ChemInform Abstract: Transformation of Solar Energy in Photosynthesis: Problems and Perspectives

ChemInformVolume 18, Issue 22 Reviews ChemInform Abstract: Transformation of Solar Energy in Photosynthesis: Problems and Perspectives A. A. KRASNOVSKII, A. A. KRASNOVSKII Inst. biokhimii AN SSSR im. Bakha, MoskvaSearch for more papers by this author A. A. KRASNOVSKII, A. A. KRASNOVSKII Inst. biokhimii AN SSSR im. Bakha, MoskvaSearch for more papers by this author First published: June 2, 1987 https://doi.org/10.1002/chin.198722355Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue22June 2, 1987 RelatedInformation

Pyroelectric properties and the nature of the polarization of polyacrylonitrile

The pyroelectric peroperties and the nature of the polarization of PAN have been investigated. The polarization that gives rise to the pyroelectric properties is caused by the “freezing in” of oriented dipole groups during cooling to room temperature in an electric field. The pyroelectric current is determined by the rotation of these dipoles around an equilibrium position as the temperature is changed. The maximum value of the pyroelectric coefficient, P, is equal to 3·9 × 10 −9 coulomb/cm 2·deg K. The production of electret films of large area and having a high value of pyroelectric coefficient makes it possible to put forward the question of using them as elements for the direct transformation of solar energy into electrical energy.

Another look at atmospheric dynamics on Titan and some of its general consequences

Mean wind velocities, U, and horizontal temperature differences, δT, are estimated for the Titan atmosphere using the similarity theory of the author. It is found that U is of order 1 m/sec and δT ∼ 0.1 K. The last value agrees with its estimate by Leovy and Pollack (1973, Icarus 19, 195–201); however the values of U are an order of magnitude less. While analyzing the causes of the difference it is found that the circulation models developed in I overestimate considerably the atmospheric efficiency in transformation of solar energy into the kinetic energy of motions. Possible reasons for such an overestimate are discussed. We conclude that the efficiency coefficient is a very sensitive characteristic of a circulation regime and that its determination is an efficient means for checking the correspondence of various circulation models with reality. Arguments are presented stressing the conclusion of I that the Titan atmospheric circulation is in the Hadley symmetric regime, which is strongly influenced by the satellite's own rotation. At the same time a thermal tide should be a noticeable feature of the circulation. In the upper part of the Titan atmosphere something like the phenomenon of the 4-day Venus circulation may be developed. It is noted that the analogy between the Titan and Venus atmospheric circulations might be a very close one.