Applied Mechanics and Materials Vol. 492

Abstract: A computational study to assess the effect of gas turbine (GT) frame size on efficiency of gas turbine power plant configurations is presented in this paper. The work includes the effect of relative humidity (RH), ambient inlet air temperature and frame size on gas turbine plant configurations with and without fogger unit. Investigation also covers economic analysis. 20 MW_e GE 5271RA, 40 MW_e GE-6561B and 70 MW_e GE-6101FA frames are selected for the present study. GT PRO software has been used for carrying out the analysis including; net plant output and net efficiency, break even electricity price (BEEP) and break even fuel LHV price (BEFP), etc. The relative humidity and temperature have been varied from 30 to 45 % and from 80 to 100° F, respectively. Fuels considered in the study are natural gas, diesel and crude oil. Results show that variation of humidity does not affect the gas turbine performance appreciably for all GT frame size regardless of type of fuel. For a decrease of inlet air temperature by 10 °F, net plant output and efficiency have been found to increase by 4 and 1.7 %, 4.2 and 1.3 %, 4.7 and 1.8 %, respectively for 20 MW,40MW and 70MW for crude oil and for GT only situation. However, for GT with Fogger scenario, for a decrease of inlet air temperature by 10 °F, net plant output and efficiency have been found to further increase by 3.1 and 1.3 %, 3 and 0.9 %, 3.2 and 1.1 %, respectively for 20 MW,40MW and 70MW. For situations with and without fogger for crude oil, BEFP have been found to vary from 1.3968 to 1.3916, 2.13 to 2.0948, 2.387 to 2.4642 USD/MMBTU respectively for 20 MW, 40MW and 70MW and BEEP have been found to vary from 0.03142 to 0.0313, 0.02488 to 0.02504, 0.0229 to 0.0233 USD/kWh respectively for 20 MW, 40MW and 70MW.

Abstract: The power management of server farms (Sf) is becoming a relevant problem in economical terms. Server farms totalize millions of servers all over the world that need to be electrically powered. Research is thus expected to investigate into methods to reduce Sf power consumption. However, saving power may turn into waste of performance (high response_times), in other words, into waste of Sf Quality of Service (QoS). By use of a Sfmodel, this paper investigates Sf power management strategies that look at compromises between power-saving and QoS. Various optimizing Sf power management policies are studied combined with the effects of job queueing disciplines. The (policy, discipline) pairs, or strategies, that optimize the Sf power consumption (minimum absorbed Watts), the Sf performance (minimum response_time), and the Sf performance-per-Watt (minimum response_time-per-Watt) are identified.By use of the model, the work the server-manager has to do to direct hisSf is greatly simplified, since the universe of all possible (strategies he needs to choose from is drastically reduced to a very small set of most significant strategies.

Abstract: Distributed generation (DG) is a recent trend of electricity generation, which aims to use various energy sources to inject electric power in a distributed manner at points close to the load. This paper develops an optimization model to choose the sizes and positions of DG in medium voltage distribution networks in order to minimize the power system losses, given a set of constraints. Ant Colony Optimization (ACO) was used as optimization technique, with excellent results.

Abstract: In this work the scheduling optimization of micro-CHP systems producing electricity and heat for a single-family house situated in Italy is addressed. Three different commercial prime movers have been analyzed separately, and for each of them the operation scheduling that maximizes the revenues for the energy cogeneration with respect to the separate generation has been evaluated by means of an optimization algorithm.

Abstract: Thermoelectric Cooler (TEC) is a semiconductor based device that has ability to separate cold and hot temperatures once the rated voltage is applied. In this study, TECs are used as Thermoelectric Generator (TEG). For this aim an experimental setup is built. By the help of this experimental setup electricity generation performances of the TEC is tested under various temperature conditions. The setup includes two water tanks, loads, TEC modules, computer interface and a data acquisition system. Temperature difference required for electrical generation of the TEC module is provided by filling the tanks with water at different temperatures. A data acquisition system is designed for this specific setup. First the setup with data acquisition system is introduced then experimental results are presented and discussed. Keywords:Electrical energy generation, Thermoelectric Cooler, LabVIEW

Abstract: This paper puts forward a distribution network reconfiguration method which takes into account voltage sag, and this method takes advantage of genetic algorithm in handling optimization problems and can optimize a superior distribution operation mode which makes the important load sag in the lowest degree besides satisfies the distribution network constraint. IEEE 16 nodes system is cited as an example. The simulation result shows that the distribution network operation mode got by the proposed method ensures the distribution network loss within reasonable limits as well as minimizes voltage sag in the important load node. This approach presented is of both efficient and practical.

Abstract: With the increasing demand of electricity dispatching and the request of energy conservation and emission reduction, the dispatching plan and operating of electric power has become more and more important. On one hand, electric power companies try to reduce power reserve as much as possible to increase the efficiency; on the other hand, some power reserve is necessary to deal with emergency and to ensure the safety and stability of grid. Therefore, this paper proposes a super short-term bus load forecasting model which is based on similar ranges to track the variation of weather and load. By using the method of fruit flies optimizing grey neural network in the real time, it can reduce the size of the network computing and solve the problem of divergence. Since the system based on the model has operated for one year, it proves that this model can meet the requirement of the precision for the electricity dispatching and adapt to the changes in different regions.

Abstract: Switching Power Supply which has a lot of advantages compared with Linear Power Supply is used very widely in the modern life. This paper discussed a kind of DC/DC switching power supply based on the UCC2800 PWM controller chip, the basic technical indicators is DC 28V rated input voltage ranging from 16V to 40V, 5V30W output, and analyzed its working principle、soft start and short-circuit protection, finally, briefly described switching power supply design methods in the use of UCC2800 PWM controller chip.

Abstract: The proposed optimal control on the basis of both current and voltage of the buck-converter is designed to be based on Inverse Linear Quadratic (ILQ) design method with the resonant low pass filter, which eliminates the disturbance by appended disturbance compensator. The designed scheme is composed of the state equation, an optimal ILQ solution, the ILQ servo-system with the disturbance elimination, the optimal basic gain, the optimal condition, the transfer functions and the disturbance compensator. Our results show the proposed strategy is the stability and robust control and has been made to improve ILQ control for the disturbance elimination of the output response, which guarantees the optimal gains on the basis of polynomial pole assignment.

Abstract: An airport flood lighting system is priority in the airport energy-saving and reducing emissions. Airport flood lighting energy-saving control system is presented by using configuration software, realizing the power acquisition, monitoring and centralized control of the ramp high-pole lamp. In automatic mode, it can integrate dynamic airport flight information to switch high-pole lamp. In the premise of ensuring flight safety at night, keeping the lights turn-on time accurately, so as to achieve the purpose of saving electricity.