Generation Efficiency (generation + efficiency)

Distribution by Scientific Domains


Selected Abstracts


Influence of needle tip distance on barrier discharge and ozone generation for multiple needle-and-plane electrode configuration

ELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 7 2010
Hideki Ueno
Abstract The relationship between the barrier discharge characteristics and ozone generation on application of an AC voltage in a triple needle-plane configuration has been investigated for various distances among the triple needle tips (d=0 to 7.0 mm) with a constant distance between the needle tip and the plane (g=3.0 mm) in dry air. The characteristics of the barrier discharge and ozone generation depend on the needle tip distance. It is considered that the influence is caused by the presence of space charge and accumulated charge, as suggested by discharge images taken by a still camera and a CCD camera. The ozone generation efficiency is also estimated from the power consumption and the ozone concentration. It is found that when the distance among the triple needle tips is small, the above influence is strengthened. In this case, the ozone generation efficiency is improved. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(7): 32,41, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10289 [source]


Dynamic characteristics of a PEM fuel cell system for individual houses

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2006
S. ObaraArticle first published online: 1 AUG 200
Abstract The method of determination of the control variables for a system controller, which controls the electric power output of a solid-polymer-membrane (PEM) fuel cell system during electric power load fluctuations, was considered. The operation was clarified for the response characteristics of electric power generation for setting the control variables of proportional action and integral action considered to be the optimal for the system controller. The power load pattern of an individual house consists of loads usually moved up and down rapidly for a short time. Until now, there have been no examples showing the characteristics of the power generation efficiency of a system that follows a load pattern that moves up and down rapidly. Therefore, this paper investigates the relation of the control variables and power generation efficiency when adding change that simulates the load of a house to PEM fuel cell cogeneration. As a result, it was shown that an operation, minimally influenced by load fluctuations, can be performed by changing the control variables using the value of the electric power load of a system. Copyright © 2006 John Wiley & Sons, Ltd. [source]


A comparative analysis of energy and CO2 taxes on the primary energy mix for electricity generation

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2005
Kris Voorspools
Abstract In many countries, economies are moving towards internalization of external costs of greenhouse-gas (GHG) emissions. This can best be achieved by either imposing additional taxes or by using an emission-permit-trading scheme. The electricity sector is under scrutiny in the allocation of emission-reduction objectives, not only because it is a large homogeneous target, but also because of the obvious emission-reduction potential by decreasing power generation based on carbon-intensive fuels. In this paper, we discuss the impact of a primary-energy tax and a CO2 tax on the dispatching strategy in power generation. In a case study for the Belgian power-generating context, several tax levels are investigated and the impact on the optimal dispatch is simulated. The impact of the taxes on the power demand or on the investment strategies is not considered. As a conclusion, we find that a CO2 tax is more effective than a primary-energy tax. Both taxes accomplish an increased generation efficiency in the form of a promotion of combined-cycle gas-fired units over coal-fired units. The CO2 tax adds an incentive for fuel switching which can be achieved by altering the merit order of power plants or by switching to a fuel with a lower carbon content within a plant. For the CO2 tax, 13 ,/tonCO2 is withheld as the optimal value which results in an emission reduction of 13% of the electricity-related GHG emissions in the Belgian power context of 2000. A tax higher than 13 ,/tonCO2 does not contribute to the further reduction of GHGs. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Enhancement of crystalline perfection by organic dopants in ZTS, ADP and KHP crystals as investigated by high-resolution XRD and SEM

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2006
S. Parthiban
To reveal the influence of complexing agents on crystalline perfection, tristhiourea zinc(II) sulfate (ZTS), ammonium dihydrogen phosphate (ADP) and potassium hydrogen phthalate (KHP) crystals grown by slow-evaporation solution growth technique using low concentrations (5 × 10,3M) of dopants like ethylenediamminetetraacetic acid (EDTA) and 1,10-phenanthroline (phen) were characterized by high-resolution X-ray diffractometry (XRD) and scanning electron microscopy (SEM). High-resolution diffraction curves (DCs) recorded for ZTS and ADP crystals doped with EDTA show that the specimen contains an epilayer, as observed by the additional peak in the DC, whereas undoped specimens do not have such additional peaks. On etching the surface layer, the additional peak due to the epilayer disappears and a very sharp DC is obtained, with full width at half-maximum (FWHM) of less than 10,arcsec, as expected from the plane wave dynamical theory of X-ray diffraction for an ideally perfect crystal. SEM micrographs also confirm the existence of an epilayer in doped specimens. The ZTS specimen has a layer with a rough surface morphology, having randomly oriented needles, whereas the ADP specimen contains a layer with dendric structure. In contrast to ADP and ZTS crystals, the DC of phen-doped KHP shows no additional peak, but it is quite broad (FWHM = 28,arcsec) with a high value of integrated intensity, , (area under the DC). The broadness of the DC and the high value of , indicate the formation of a mosaic layer on the surface of the crystal. However, similar to ADP and ZTS, the DC recorded after etching the surface layer of the KHP specimen shows a very sharp peak with an FWHM of 8 arcsec. An SEM photograph of phen-doped KHP shows deep cracks on the surface, confirming the mosaicity. After removing the surface layer, the SEM pictures reveal a smooth surface. A similar trend is observed with other complexing agents, like oxalic acid, bipy and picolinic acid. However, only typical examples are described in the present article where the effects were observed prominently. The investigations on ZTS, ADP and KHP crystals, employing high-resolution XRD and SEM studies, revealed that some organic dopants added to the solution during the growth lead to the formation of a surface layer, due to complexation of these dopants with the trace metal ion impurities present in the solution, which prevents the entry of impurities, including the solvent, into the crystal, thereby assisting crystal growth with high crystalline perfection. The influence of organic dopants on the second harmonic generation efficiency is also investigated. [source]