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[en] A hybrid thermal energy storage system (HTESS) is proposed for managing simultaneously the storage of heat from solar and electric energy. Solar energy is stored during sunny days and released later during cloudy days or at night, and to smooth power demands, electric energy is stored during off peak periods and later used during peak periods. A heat transfer model of the HTESS is developed and validated with exact solutions and experimental data. Simulations are then performed to examine the effect of various storage materials and of the operating conditions on the thermal behaviour of the HTESS. The results indicate that the consumption of electricity for space heating is minimised when the HTESS consists of a 0.15 m thick wall comprising spherical capsules 0.065 m in diameter filled with n-octadecane. With such a system, the electric energy consumption during the month of January may be reduced by as much as 30%
[en] Solar drier does not degrade any more the dried products with the manner of the products dried at the natural sun. The drying unit is composed mainly of a solar air collector and an enclosure of drying. The transformation of the solar radiation into heat is done thanks to the solar collector whose effectiveness is increased by the addition of suitable baffles in the mobile air vein. The efficiency of the collector reaches then 80. The hot air on the outlet side of the collector arrives in the enclosure of drying where the heat transfer with the product to be dried is done by convection. The kinetics drying study shows that in addition to the dependence of the temperature and air velocity of drying, the speed of drying also depends on fragmentation on the product to dry, and mainly, of the product surface in contact with the drying air. Thus, the hygrometry is reduced from 76 to 13 pour cent in one day.. The total efficiency of the drier reached 28 pour cent
[en] In the present contribution, some related fundamental problems of revealing micro mechanisms of hydrogen plasticization, superplasticity, embrittlement, cracking, blistering and delayed fracture of some technologically important industrial metallic materials are formulated. The ways are considered of these problems' solution and optimizing the technological processes and materials, particularly in the hydrogen and gas-petroleum industries, some aircraft, aerospace and automobile systems. The results are related to the safety and standardization problems of metallic materials, and to the problem of their compatibility with hydrogen. (authors)
[en] This paper examines the effect of vertical and horizontal shading devices on the quality of daylight in buildings and the associated energy saving. Excessive daylight in architectural spaces contributes negatively to the energy consumption in buildings. Blinds and shading devices are good solutions to attenuate the surplus amount of daylight in spaces. Accordingly, this study evaluates the effect of shading devices on the amount of light flux and the associated solar energy in buildings. It estimates the energy consumption attributed to lighting spaces for three common positions of shading devices. Computer simulation strategy was undertaken to correlate the illuminance level in spaces with room geometry and architectural shading elements. The Holophane model for lighting calculations was used to estimate the average illuminance level on workplane and correlate it with the expected saving energy in buildings. The study concluded that there is an optimal orientation for shading devices that keeps the internal illuminance level within the acceptable range with minimum amount of solar heat gain.
[en] The potential energy curve (PEC) of HI(X1Σ+) molecule is studied using the complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration interaction approach at the correlation-consistent basis sets, aug-cc-pV6Z for H and aug-cc-pV5Z-pp for I atom. Using the PEC of HI(X1Σ+), the spectroscopic parameters of three isotopes, HI(X1Σ+), DI(X1Σ+) and TI(X1Σ+), are determined in the present work. For the HI(X1Σ+), the values of D0, De, Re, ωe, ωeχe, αe and Be are 3.1551 eV, 3.2958 eV, 0.16183 nm, 2290.60 cm−1, 40.0703 cm−1, 0.1699 cm−1 and 6.4373 cm−1, respectively; for the DI (X1Σ+), the values of D0, De, Re, ωe, ωeχe, αe and Be are 3.1965 eV, 3.2967 eV, 0.16183 nm, 1626.8 cm−1, 20.8581 cm−1, 0.0611 cm−1 and 3.2468 cm−1, respectively; for the TI (X1Σ+), the values of D0, De, Re, ωe, ωeχe, αe and Be are of 3.2144 eV, 3.2967 eV, 0.16183 nm, 1334.43 cm−1, 14.0765 cm−1, 0.0338 cm−1 and 2.1850 cm−1, respectively. These results accord well with the available experimental results. With the PEC of HI(X1Σ+) molecule obtained at present, a total of 19 vibrational states are predicted for the HI, 26 for the DI, and 32 for the TI, when the rotational quantum number J is equal to zero (J = 0). For each vibrational state, vibrational level G(v), inertial rotation constant Bv and centrifugal distortion constant Dv are determined when J = 0 for the first time, which are in excellent agreement with the experimental results. (atomic and molecular physics)
[en] In a lot of sites, at best, only global irradiations on horizontal planes are available. As most systems using solar energy are tilted, it is obvious that these data are not sufficient. The purpose of our work consists in predicting the solar irradiation on inclined surfaces based on horizontal measurements. To reach this goal, two previous studies were performed. They consisted in quantifying the accuracy of various well-known models of the literature: the first type of models (seven correlations) calculated diffuse horizontal irradiations from global ones and the second type (fifteen models) computed global irradiations on inclined planes from diffuse and global components on a horizontal surface. This study combines the two classes of models and calculates the adequacy of each association for experimental hourly data collected on the French Mediterranean site of Ajaccio. We compared these combinations with the Olmo model, transforming global irradiations directly onto tilted planes from horizontal ones
[en] A solar tower is a renewable energy plant, designed to channel the air warmed by the sun, in order to produce electric power by the use of turbines. It is composed of a giant greenhouse with a chimney in its center. The capacity of this system is proportional to the chimney high. That is the reason why french engineers proposed to use the hillsides to build chimneys of many kilometers high. The project and some technical informations are provided in this paper. (A.L.B.)
[en] We present the analytical results at the mean-field level for the asymmetrical fermion system with attractive contact interaction at zero temperature. The results can be expressed in terms of linear combinations of the elliptic integrals of the first and second kinds. In the limit of small gap parameter, we discuss how the asymmetry in fermion species affects the phases of the ground state of the system. In the limit of large gap parameter, we show that two candidate phases are competing for the system's ground state. The Sarma phase containing a pure Fermi fluid and a mixed condensate is favored at a large degree of asymmetry. The separated phase consisting of a pure Fermi fluid and a boson condensate supports the system at a small degree of asymmetry. The two phases are degenerate in the limit of infinite pairing gap
[en] Hydrogen production, transport, and usage in future passenger car transportation systems is compared for selected solar and conventional hydrogen production technologies using a comprehensive life cycle assessment (LCA) approach. Solar scenarios show distinctly lower greenhouse gas (GHG) emissions than fossil-based scenarios. For example, using solar produced hydrogen in fuel cell cars reduces life cycle GHG emissions by 75% compared to advanced gasoline vehicles and by more than 90% if car and road infrastructure are not considered. Utilization of solar produced hydrogen has the potential of reducing fossil energy requirements by a factor of up to 10 compared to conventional technologies. Environmental impacts are associated with the construction of the steel-intensive infrastructure for concentrating solar power plants due to mineral and fossil resource consumption as well as discharge of pollutants related to today's non-sustainable steel production technology. (authors)
[en] This book is a science comic book for students in elementary school, which contains energy and life such as our body and energy, animal and energy, plant and energy, kinetic energy, potential energy and the principle of the conservation of energy in the first part. The second part explains fossil fuel like coal, petroleum and natural gas. Next it deals with electric power, nuclear energy such as atom and molecule, nuclear fusion and energy for future like solar cell and black hole power plant.