Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 5 Articles
Load flow is an important tool used by power engineers for planning, to determine the best operation\nfor a power system and exchange of power between utility companies. In order to have an efficient\noperating power system, it is necessary to determine which method is suitable and efficient\nfor the system�s load flow analysis. A power flow analysis method may take a long time and therefore\nprevent achieving an accurate result to a power flow solution because of continuous changes\nin power demand and generations. This paper presents analysis of the load flow problem in power\nsystem planning studies. The numerical methods: Gauss-Seidel, Newton-Raphson and Fast Decoupled\nmethods were compared for a power flow analysis solution. Simulation is carried out using\nMatlab for test cases of IEEE 9-Bus, IEEE 30-Bus and IEEE 57-Bus system. The simulation results\nwere compared for number of iteration, computational time, tolerance value and convergence.\nThe compared results show that Newton-Raphson is the most reliable method because it\nhas the least number of iteration and converges faster....
Aluminum, in its normal passive oxidized state, does not react with water. In this work, aluminum\nactivation is carried out using liquid metal eutectics Ga-In-Sn-Zn (60:25:10:5). Subsequently, the\nreaction with water of activated aluminum to produce hydrogen has been examined. The effects of\naluminum particle size, liquid eutectics content, and reaction temperature on hydrogen production\nrates are investigated. The liquid eutectics interaction with aluminum is discussed and the\nmechanisms of liquid eutectics penetration within the Al particles have been investigated. The\nspecific surface area of the Al particles, the mass ratio of Al to eutectics content and the reaction\ntemperature were found to determine the hydrogen production rate and yield. It is observed that\nmicro-aluminum particles of ~30 �¼m size display lower reaction rates and hydrogen yields than\n~350 �¼m size particles....
To realize the goal of harvesting energy from pavement vibration on a large scale, a new type of\npiezoelectric harvesting units as the energy transducer has been proposed. The piezoelectric harvesting\nunits are paved 40 mm below the asphalt, which is the same as thickness of the top layer of\ntypical asphalt pavement in China. The spacing distance is 2200 mm, which is the same as the one\nbetween two tires of a normal vehicle. A mathematical model of the unit is deduced on Meda empirical\nformula and Hamilton principle and piezoelectric equations. Effects of the external vehicle\nload on its harvesting energy properties and pavement deformation and stress are analyzed with\nthe finite element method. The results show that the excited voltage is linearly variation with\ncontact pressure while the harvested electrical energy exponential varies with contact pressure.\nThe more the contact pressure is, the larger the harvested electrical energy and the deformation\nand stress are. The harvested electrical energy also increases with the load frequency. At least 100\nmJ of electrical energy can be collected with the proposed piezoelectric harvesting unit. It shows\nthat the technology application of the piezoelectric harvesting energy from pavement is promising....
The ERA-Interim reanalysis wind based on the distance-weighted average remapping for studying\nthe wind circulation in Nigeria is presented. The wind flow using this atmospheric model simulation\nis studied for identification of grid-tie electrification opportunities in different wind locations.\nA 10-year reanalysis wind speed components at a surface level of the planetary layer at 0.25 Ã?â??\n0.25 spatial resolution is obtained and remapped into a new horizontal wind field at a grid resolution\nof 0.125 Ã?â?? 0.125 covering longitudinal and latitudinal directions of 3.0 - 15.0E and 15.0 -\n3.0N, respectively. Using the distance-weighted average technique, the remapped wind field at a\nnew grid resolution of 0.125 Ã?â?? 0.125 is compared at different terrain elevations and approximated\nclose to the actual wind field of the same resolution. To determine the suitability of the\nprevailing wind for small-scale energy conversion, the magnitude of wind flow across the remapped\nwind field is studied for a 10-year period. Analysis shows that northern regions of Nigeria\nhave a fair wind potential for a stand-alone application based on the wind flow originated at Gulf\nof Guinea as well as Chad and Niger. Furthermore, hourly surface wind speed observations from\n18 synoptic stations in Nigeria are obtained and compared with the bilinear interpolated wind\nstations. The reanalysis wind reflects the surface wind observations and proves that the prevailing\nwind in Nigeria is higher than the reanalysis wind projection obtained from gridded data at resolution\nof 0.125 Ã?â?? 0.125. The sectorwise wind directions at each synoptic stations for a period of\n10 years are presented....
This paper focuses on the residential housing performance and people�s lifestyle in terms of\nenergy use. The research has to be continuously study in order to change the Asian people�s lifestyle\nmoving toward the low energy consumption. The research began with collecting data by\nquestionnaires which already distributed to some cities of some countries in Asia. In this paper,\nwe conducted review of energy behavior in housing of three different countries, Indonesia, China,\nand Thailand. Through questionnaire surveys distributed to more than 600 households, we revealed\nthe housing unit characteristics, household characteristics, ownership of domestic electrical\nappliances, use of indoor thermal equipment, and monthly energy use. Based on questionnaire\nresults from all households in the seven districts, we conducted statistical analyses to find\nthe major factors influencing the energy use in households. Finally, the research results will be\nused to indicate the energy use and develop an idea for energy conservation in Asian countries.\nFor further studies, the researchers also try to discover the new way of changing the people�s lifestyle\nin terms of energy consumption....
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