The Experts below are selected from a list of 48216 Experts worldwide ranked by ideXlab platform
Arefy. Maalej - One of the best experts on this subject based on the ideXlab platform.
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Solar still performance
Desalination, 1991Co-Authors: Arefy. MaalejAbstract:Abstract This investigation includes the study of the performance rating and efficiency of a solar still operating under different conditions. The solar still was designed and built in the Mechanical Engineering Department at the Ohio State University. The three major variable factors in the still performance are the Insolation, the wind velocity and the insulation of the system. The experimental part of the study consists of running the experiment with different sets of conditions. The theoretical part includes the development of a math model for the solar still and the numerical prediction of the still performance using computer simulation. Both the dynamics and the steady state performance of the still are studied. Based on the experimental and mathematical model results, it was concluded that the best performance of the solar still is achieved when the following conditions are satisfied: 1. - High intensity of Insolation 2. - Full Insulation 3. - Minimum wind velocity Under these conditions, a maximum solar still efficiency of approximately 50 % is obtained. While the intensity of the Insolation has a proportional effect on the productivity of the solar still system, The type of insulation effects considerably the still performance. A light insulation causes a reduction of 14.5% in the efficiency obtained with full insulation. The wind effect is much more limited. The increase of wind velocity from zero to 3.6 mph yielded a slight reduction ( 2%) in the the still performance.
Gerrit Lohmann - One of the best experts on this subject based on the ideXlab platform.
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synchronicity of antarctic temperatures and local solar Insolation on orbital timescales
Nature, 2011Co-Authors: Thomas Laepple, Martin Werner, Gerrit LohmannAbstract:Records of past temperatures derived from Greenland and Antarctic ice cores are important for the understanding of the global climate system on long timescales. According to Milankovitch theory, glacial to interglacial climate variability as recorded in Antarctic ice cores is governed by summer Insolation — the amount solar of radiation received at Earth's surface — at high northern latitudes. Thomas Laepple and colleagues now show that accumulation of Antarctic snow is biased towards austral winter and may be explained simply by variations in local Insolation, with no recourse to northern influences. Although the results do not constitute a complete negative proof, they show that the Antarctic ice core records do not, in themselves, provide sufficient support for Milankovitch theory. According to the Milankovitch theory, glacial to interglacial climate variability — as recorded in Antarctica ice cores — is governed by summer Insolation at high northern latitudes. It is now shown that accumulation of Antarctic snow is biased towards austral winter and may be explained simply by variations in local Insolation, with no recourse to northern influences. Although not constituting a complete negative proof, the results show that the Antarctic ice core records do not, in themselves, provide sufficient support for the Milankovitch theory. The Milankovitch theory states that global climate variability on orbital timescales from tens to hundreds of thousands of years is dominated by the summer Insolation at high northern latitudes1,2. The supporting evidence includes reconstructed air temperatures in Antarctica that are nearly in phase with boreal summer Insolation and out of phase with local summer Insolation3,4,5. Antarctic climate is therefore thought to be driven by northern summer Insolation5. A clear mechanism that links the two hemispheres on orbital timescales is, however, missing. We propose that key Antarctic temperature records derived from ice cores are biased towards austral winter because of a seasonal cycle in snow accumulation. Using present-day estimates of this bias in the ‘recorder’ system, here we show that the local Insolation can explain the orbital component of the temperature record without having to invoke a link to the Northern Hemisphere. Therefore, the Antarctic ice-core-derived temperature record, one of the best-dated records of the late Pleistocene temperature evolution, cannot be used to support or contradict the Milankovitch hypothesis that global climate changes are driven by Northern Hemisphere summer Insolation variations.
Henry Shuhung Chung - One of the best experts on this subject based on the ideXlab platform.
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an integrated inverter with maximum power tracking for grid connected pv systems
IEEE Transactions on Power Electronics, 2005Co-Authors: B M T Ho, Henry Shuhung ChungAbstract:An inverter for grid-connected photovoltaic systems is presented in this paper. It can globally locate the maximum power point of the panel over wide Insolation and feed the solar energy to the grid. Its structure mainly integrates a previously developed maximum point tracking method and output current shaping function into a buck-boost-derived converter and then inverts the shaped current through a grid frequency bridge to the grid. Instead of having a storage capacitor connecting in parallel with the converter output, series connection is used, so that the required capacitor voltage rating is lower than that in classical inverters. Most importantly, the inverter output current harmonics are less sensitive to the capacitor value. A 30-W laboratory prototype has been built. The tracking capability, inversion efficiency, and large-signal responses at different Insolations have been investigated. Detailed analysis on the inverter performance has been performed. The theoretical predictions are verified with the experimental results.
Tomonobu Senjyu - One of the best experts on this subject based on the ideXlab platform.
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fuzzy control of distributed pv inverters energy storage systems electric vehicles for frequency regulation in a large power system
IEEE Transactions on Smart Grid, 2013Co-Authors: Manoj Datta, Tomonobu SenjyuAbstract:This paper presents a fuzzy based frequency control strategy by the Megawatt (MW) class distributed PV systems and electric vehicles (EVs). The frequency control is proposed from the view point of the frequency fluctuation problem produced by the large penetration of PV power and sudden load variation. The fuzzy based frequency control has three inputs: average Insolation, change of Insolation and frequency deviation. Following these three inputs, a frequency control system for the distributed PV inverters is proposed. For the case of different Insolations in the different areas of the power system, a coordinated control method of the distributed PV inverters, energy storage systems (ESSs) and EVs is presented. The proposed method is simulated by considering dual power and information flows between supply and demand sides in a large power system and is found satisfactory to provide frequency control and to reduce tie-line power fluctuations.
S.d. Probert - One of the best experts on this subject based on the ideXlab platform.
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Cheap effective thermal solar-energy collectors
Applied Energy, 1996Co-Authors: Donald James Highgate, S.d. ProbertAbstract:A light-weight flexible solar-collector, with a wavelength-selective absorption surface and an Insolation-transparent thermal-insulation protector for its aperture, was built and tested. Its cheapness and high performance, relative to a conventional flat-plate solar-collector, provide a prima-facie case for the more widespread adoption of its design.
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Solar-control films
Applied Energy, 1992Co-Authors: Philip Griffiths, S.d. Probert, W.j. Batty, C. KnightAbstract:The magnitude of the transmittance of solar radiation through glass is dependent upon its angle of incidence, the emissivity of the glass surface and the length that the light beam travels through the glass. To alter the emissivity of a glass surface a solar-control film can be attached to it. However, none of the present generation of [`]solar' films that are applied to transparent glass surfaces is able to inhibit Insolation gain during the summer while providing satisfactory thermal-radiation insulation with respect to energy leaving the building during the winter. This is because different wavelengths of radiation need to be inhibited for these two processes to be successful, namely short-wave radiation in the case of Insolation and long-wave radiation for thermal insulation. Neither of these films inhibits glare satisfactorily. As expected, the energy transmittance and rate of heat gain by the affected room decrease as the angle of incidence (of the energy source, i.e. the sun, with respect to the glass) increases. Also the magnitude of this rate of heat gain depends upon the type (reflective, insulating or absorptive) of solar-control film applied to the glass.
