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The in-cylinder pressure of internal combustion engines is one of the most important measurable parameter for analyzing the factors affecting performance characteristics of the engine. In many studies, in-cylinder pressure data are averaged over certain number of cycles at each crank angle in order to observe the effects of the parameters. If the number of cycles included is low, then the results...
This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During the hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded...
This paper deals with a numerical analysis of the evaporation of binary liquid film. The film is falling down on one plate of a vertical channel under mixed convection channel. The first plate of a vertical channel is externally submitted to a uniform heated flux q 1 while the second one (y=d) is dry and isothermal. The liquid mixture consists of water (the more volatile component) and ethylene...
This research is trying to develop a new procedure for retrofit of HENs including pressure drop using genetic algorithm (GA) coupled with linear programming (LP) and integer linear programming (ILP) methods. The GA is used to produce structural modifications whereas continuous variables are handled using a converted NLP formulation for Maximum Energy Recovery (MER). The converted NLP consists of an...
Proton-conducting polymer membranes are used as an electrolyte in the so-called proton exchange membrane fuel cells. Commercially available membranes are perfluosulfonic acid polymers, a class of high-cost ionomers. This paper examines the potential of polymer blends, namely those of sulfonated polystyrene ethylene butylene polystyrene (SPSEBS) and polysulfone (PSU), in the proton exchange membrane...
Simultaneous transport of heat and moisture by conjugate natural convection in a partial enclosure with a solid wall is investigated numerically. Moist air motions are driven by the external temperature and concentration differences imposed across enclosures with different ambient moisture conditions. The Prandtl number and Schmidt number used are 0.7 and 0.6, respectively. The fluid, heat and moisture...
A novel cogeneration system was proposed and techno-economically investigated, consisting of a low-temperature geothermally-powered organic Rankine cycle (ORC) subsystem, an intermediate heat exchanger subsystem and a heat pump subsystem. The main purpose is to identify suitable working fluids (among 27 fluids with boiling point temperature ranging from −47.69 to 47.59°C) and optimized cycle parameters...
This work develops a new approach for optimal energy management of electrical distribution ‘smart-grids’. Optimality aims at improving sustainability through the minimization of carbon emissions and at reducing production costs and maximizing quality. Input data are the forecasted loads and productions from renewable generation units, output data are a set of control actions for the actuators. The...
The naval submarines have conventionally been equipped with diesel-electric propulsion. The diesel generators charge the batteries when the submarine is at the surface or at snorkelling depth. This is the biggest short-coming of this system as the submarine can be detected due to the infrared signatures from the exhaust of engines. Present study aims in analysing the feasibility of using fuel cells...
Complex turbines with multiple controlled and/or uncontrolled extractions are popularly used in the processing industry and cogeneration plants to provide steam of different levels, electric power, and driving power. To characterize thermodynamic behavior under varying conditions, nonlinear mathematical models are developed based on energy balance, thermodynamic principles, and semi-empirical equations...
In the present study, using a previously developed dynamic mathematical model for performance analysis of an indirect cabinet solar dryer [1], a microscopic energy and exergy analysis for an indirect solar cabinet dryer is carried out. To this end, appropriate energy and exergy models are developed and using the predicted values for temperature and enthalpy of gas stream and the temperature, enthalpy...
This paper presents a method for estimating the maximum pressure of steam which can be generated in recovering heat from individual processes, by partial linearization of the grand-composite curve. The technique is based on the pinch-analysis method by using a grand-composite curve (GCC), which can be approximated by using a mathematical function. The mathematical linear technique is composed of two...
The empirical model of turbine efficiency is necessary for the control- and/or diagnosis-oriented simulation and useful for the simulation and analysis of dynamic performances of the turbine equipment and systems, such as air cycle refrigeration systems, power plants, turbine engines, and turbochargers. Existing empirical models of turbine efficiency are insufficient because there is no suitable form...
An accurate battery State of Charge estimation is of great significance for battery electric vehicles and hybrid electric vehicles. This paper presents an adaptive unscented Kalman filtering method to estimate State of Charge of a lithium-ion battery for battery electric vehicles. The adaptive adjustment of the noise covariances in the State of Charge estimation process is implemented by an idea of...
Direct solar drying characteristics of Amelie and Brooks mangoes were experimentally determined using a solar dryer made up of four trays and used under weather conditions of fruit harvest period. Direct solar drying curves were established, fitted using 10 mathematical models and simulated with a direct solar drying model. Effective diffusivity, drying rates and drying efficiency were estimated for...
In a gas/particle two-phase testing facility with the use of a three-component particle-dynamics anemometer, we determine the influence of secondary air mass flow rates on gas/particle flow characteristics in the near-burner region of a centrally fuel-rich swirl coal combustion burner. Velocities, particle volume flux profiles and normalized particle number concentrations were obtained. The peaks...
The present work deals with a numerical procedure for optimizing a cooling channel with staggered elliptic dimples to enhance heat transfer and also to reduce the pressure loss. Three-dimensional Reynolds-averaged Navier–Stokes analysis is employed in conjunction with the SST model for predicting the turbulent flow and heat transfer. Three non-dimensional geometric design variables, such as the elliptic...
A data-mining approach for the optimization of a HVAC (heating, ventilation, and air conditioning) system is presented. A predictive model of the HVAC system is derived by data-mining algorithms, using a dataset collected from an experiment conducted at a research facility. To minimize the energy while maintaining the corresponding IAQ (indoor air quality) within a user-defined range, a multi-objective...
Energy companies can adjust the estimation of their reserves. We investigate how these revisions impact on the value of these firms. We analyze 100 revisions in seventeen countries for the period 2000-2010. We use an event study and find that the revisions of energy reserves significantly impact on the market value of the firm. We also discover an asymmetry in this response as the market’s reaction...
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