JOURNAL OF ENERGY MANAGEMENT
Year:2012 | Volume:2 | Issue:1|Papers Count:7

Load serving entities (LSE) of industrial district that have the operation responsibility of electric network, must procure the consumers electricity from wholesale electric market or the utility’s distributed generation (DG). The generation expansion planning (GEP) has a crucial impact on the optimality of LSE’s operation. In this paper, an innovative GEP is presented in which the location, time scheduling, heat and load capacity of combined heat and power generation units are determined based on a semi dynamic scheduling. The proposed algorithm uses a genetic algorithm for minimizing of LSE’s operation costs and it considers the heat/electric load following characteristics of DGs’. A case study is performed for a medium voltage feeder of industrial district, which its results approve the optimality of the solution.

This paper presents nonlinear frequency control characteristic for a dispatchable source to reduce fuel consumption in a standalone AC power system. Power management used in grid is local. The proposed frequency characteristics that are employed for the sources are designed based on grid model. To have robust frequency control characteristics, uncertainty in grid model that consists of load model and line impedance parameters uncertainties are considered. In other word, the parameters of the proposed frequency characteristics are computed with existing uncertainty in grid model. The frequency characteristics are designed as piecewise linear characteristics between two load levels in the grid. By solving an off-line optimization problem, the parameters of proposed frequency characteristics are obtained. Simulation results shows performance of the proposed frequency characteristics that caused reduction in fuel consumption and robustness respect to grid model uncertainty.

Several relations are presented in order to specify blasting dynamic loading associated with analytical, field and experimental analysis. Dynamic loading type, maximum pressure and consequent duration time can affect the numerical simulation results of fragmentations, damage zone and maximum radial crack length in the vicinity of the blast hole and ground vibrations. These in turn depend on the maximum explosion pressure, applied loading time and the type of explosion function (pressure versus time) which determine the area under the pressure-time curve. In this article, different common correlations for dynamic loading of explosions are simulated using UDEC numerical discrete element software and the results are compared with field studies obtained from PETN explosions used in the conglomerate rockmass in GotvandOlya dam. Considering the mutual explosive and rockmass characteristics, the maximum applied pressure to the blast hole was found to be 4.59GPa based on both Liu and Tidman semi-empirical relationship and Gamma constant law. Results of numerical and field studies suggest that Yon and Jeon relation coincide with the field study data, considering the 1.0m radial crack length, ground vibrations recorded during the field tests at 5m and 12m distances from the blast hole are 42.36 and 7.91 mm/s, respectively.

In the present paper, experimental and numerical investigation of a laboratory oil furnace have been done to study the effect of inlet air swirl angle on temperature and generating of pollutant CO and NO. The Concentration of pollutant CO and NO on the centerline of the furnace have been measured using gas analyzer. The numerical results are in good agreement with experimental data. The results show that the effect of vane swirl angle on the pollutant emission is significant and an optimum vane swirl angle can cause enhancement of thermal efficiency and reduction in pollutant emission. Increasing vane angle from 0 to 75 degree caused to first increase temperature and pollutant NO to a maximum value and then decreases them. Also, the results show that very large and small vane swirl angles cause to increase the concentration of CO outlet of the furnace and reduction of thermal efficiency. According to the results obtained in this study, the vane swirl angle of inlet air in the furnace can be adjusted to optimize pollutant generation and operation of furnace in desirable condition.

Due to an increasing need of energy, lack of energy resources worldwide, it is very important to optimize energy generation plant to improve efficiency and production rate. One of the most important plant, for production of water and power are dual purpose power plants. In this kind of power plant a desalination system combines with power generation cycle. According to these issues, in this paper a multi effect desalination (MED) is coupled with combined power plant through heat recovery steam generator (HRSG). After simulating desalination system, HRSG and steam cycle, the effect of system operating parameters on total exergy efficiency, water and power production rate are studied. As a result, steam turbine power increases with an increment of pressure for high pressure levels up to a maximum point, and then decreases. This maximum value increases with a decrease in pressure for the high and low pressure levels, simultaneously.

A comprehensive exergy analysis of a suggested heat pump using low temperature geothermal surface water in Ramsar is carried out in this paper. Analytical formulas for exergy loss, exergy efficiency, exergy loss ratio, exergy loss coefficient and thermodynamic perfect degree are presented for whole and every single component of the system. This analysis is done in heating and cooling mood. It is resulted that all these indexes must be used integrative for a comprehensive exergy analysis. It is concluded that compressor is location of maximum values of exergy loss, exergy loss coefficient and exergy loss ratio, and minimum values of exergy efficiency and thermodynamic perfect degree. Therefore first important component to improve achievement of better efficiency of system is compressor. The other components to improve are fan coil, ground heat exchanger and condenser (in cooling mood). Results of this analysis can be used for design and optimization of a heat pump using mentioned available resources.

Austenitic stainless steels are widely-used to fabricate equipments for energy systems such as oil, gas industries and power plants. Therefore, proper selection of cutting parameters may play an important role in decreasing the price of generated energy. However especial mechanical properties distinguish this type of steels from the others. High ductility and high work hardening tendency are the main factors that make their machinability difficult with common utilities such as poor surface finish and high tool wear. In this study, a few sets of experimental data is considered to develop a mathematical model for computing actual surface roughness with implementing the role of cutting speed to modify available model for apparent surface roughness depending on only feed rate and tool nose radius. In order to determine the optimum cutting parameters for austenitic stainless steel with its special properties, step by step calculation procedure is presented in this study taking into account some manufacturing concerns neglected in other available tables and charts. The results of this paper gives this opportunity to machinists to select cutting condition based on their own need including minimum manufacturing expenses or time, and maximum metal removal rate.