Volume 2 Issue 1
Authors: M. S.Söylemez
Abstract: A thermo economic optimization analysis is presented yielding simple algebraic formula for estimating the optimum operating temperatures for three different types of heat exchangers which are applied in industrial applications. An economic analysis method is used in the present study, together with the thermal analyses of heat exchangers, for thermo economic optimization of all of the three different types of heat exchanger. The validity of the optimization formulations was checked.
Keywords: Thermo economics; Heat exchanger; Cost optimization
Authors: Fatimah De’nan; Nor Salwani Hashim
Abstract: The structural action of a beam is predominantly bending, with other effects such as shear, bearing and buckling also being presented. Due to the more application of corrugated section in steel design, this paper develops a three-dimensional finite element model using LUSAS 14.3 to investigate the effects of web corrugation angle on bending behavior of Triangular Web Profile (TRIWP) steel sections. A triangular web profile (TRIWP) steel section is a built-up steel section made up of two flanges connected to a web plate of triangular profile. Thin shell element was chosen to represent the element type of the model. Two sizes of flat webs (FW) as control specimens and two sizes of TRIWP which are 200×100×6×3 mm and 180×75×5×2 mm section were used. Each of beam section was modeled using several spans such as 3 m, 4 m and 4.8 m and different corrugation angles (150,300,450,600 and 750). It was noted that deflection of 450 and 750 web corrugations angle be the lowest deflection value either in minor or major axis of TRIWP steel section. It means that the TRIWP steel section is stiffer when the web corrugation angle is 450 or 750. In other word, TRIWP steel section has a higher resistance to bending in minor and major axis when the web is used in both corrugation angles.
Keywords: Finite Element Model; Bending; Triangular Web Profile
Authors: Ambarish Datta; Achin Kumar Chowdhuri; Bijan Kumar Mandal
Abstract: The excessive use of fossil fuels will certainly lead to the energy crisis and unsustainable condition of the environment in future. In this paper, the performance characteristics have been studied experimentally for a spark ignition engine running with different gasoline-alcohol (ethanol and methanol) blends as alternative fuels. It is observed that the brake thermal efficiency increases by more than 6% with 40% addition of ethanol or methanol to gasoline. Volumetric efficiency also increases due to alcohol addition to gasoline. Brake specific fuel consumption increases approximately by 20% with 30% alcohol addition. The maximum exhaust gas temperature decreases by 14% with methanol and 10% with ethanol for a blending of 40% alcohol with gasoline by volume.
Keywords: SI Engine; Ethanol; Methanol; Blend; Performance
Authors: S. Rama Reddy; C. Umayal
Abstract: In this work a bridgeless PFC boost rectifier is proposed to reduce harmonic current of a BLDC motor. The aim of the work is to improve the input power factor of PMBLDC drive. Conventional bridged PFC topology is replaced by bridgeless PFC topology. Conventional VSI fed BLDC motor suffers from the high conduction loss in the input rectifier-bridge. Higher efficiency can be achieved by using the bridgeless boost topology. Performance comparison between the VSI fed BLDC motors with filters and the bridgeless boost rectifier fed BLDC motor are presented. The simulation results with bridgeless boost converter show that there is an improvement in power factor. The hardware is fabricated and tested. Simulation and experimental results of these systems are presented and the performance measures are compared. Experimental measurements agree acceptably with simulation results, and validate the proposed methods.
Keywords: Boost rectifier; low conduction losses; Power factor correction (PFC); PMBLDC motor
Authors: Wang Bing; Liu Xiaoye; Liu Chunyu; Yue Liran; Li Yongfeng; Han Wei
Abstract: This study evaluated the possibility of using granular activated carbon as support material for biohydrogen production in a continuous stirred tank reactor (CSTR). The CSTR was inoculated with aeration pre-treated sludge and operated at temperature of 36 °C and hydraulic retention time (HRT) of 6 h. It was found that both biogas and hydrogen yields increased with OLR at the range of 8-24 d. The biogas was mainly composed of CO2 and H2 with the percentage of H2 ranging from 38.4% to 41% in biogas. The maximum hydrogen production rate of 3.65 L was obtained in the reactor at OLR of 24 kg/m3d. The granular activated carbon could make the hydrogen-producing system stable regarding hydrogen production, pH value and microbial by-products and could be used as support material for fermentative hydrogen production.
Keywords: Hydrogen production; Continuous stirred tank reactor; Fermentation; Support material; Molasses
Authors: D. Hazarika
Abstract: The paper describes an algorithm for assigning transmission cost to generator(s) and load(s) based on sensitivity relation between line power flow and power generation from generating stations and loads. It allows formulation of cost function for generating station containing cost co-efficient representing transmission line power flow assigned to generating stations. As a result, solution of co-ordination equation for determining optimum generation scheduling involves transmission cost pertaining to the generating station. This ensures better co-ordination of transmission cost in optimal generation scheduling and reduction in transmission cost. Further, it allows assigning of transmission cost to the loads that are drawing power through the line.
Keywords: Power System Planning, Optimal Load Dispatch, Sensitivity Factor, Transmission Cost