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Off-grid rural electrification project configurations which consider hybrid generation systems based on multiple renewable sources and the implementation of micro-grids are the most promising design solutions. The efficient design of those systems is a complex task that is facing several technical issues such as limited time and resources available for the purpose, especially in developing countries...
Due to a good behavior of ammonia-water during the two-phase heat addition process and the liquefied natural gas with great cold energy, an ammonia-water power system with LNG as its heat sink is proposed to utilize the low grade waste heat. Based on the thermodynamic mathematical models, the effects of key thermodynamic design parameters, including turbine inlet pressure, turbine inlet temperature,...
A conceptual biorefinery, based on repurposing a kraft pulp mill, has been studied. In the process an alkaline pre-treatment unit separates the incoming wood raw-material to a cellulose-rich pulp and a residue liquor containing dissolved lignin. The pulp is sent to an ethanol line, while the liquor is gasified and refined to dimethyl ether. The concept has been designed and assessed from an energy...
Thermal load calculation based on dynamic models is widely used in simulation software and it is the method recommended by ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) and CEN (European Committee for Standardization, in French: Comité Européen de Normalisation). The principle is to make the heat balance for the air volume of a room space considered at uniform...
The objectives of this study were to analyze energy use and greenhouse gases (GHG) emissions in various wheat production scenarios in north eastern Iran and to identify measures to reduce energy use and GHG emissions. Three high-input, a low-input, a better crop management and a usual production scenarios were included. All activities and production processes were monitored and recorded. Averages...
Tars formation remains the main technical hurdle in the development of biomass gasification at commercial scale, due to its associated operating problems (condensation, catalyst deactivation, polymerisation). This work aims to study the effect of the operating conditions (biomass/air ratio, temperature and gasifying agent) on the production and the technical and environmental hazard (tar dew point...
The acidification of the aqueous phase induced by the use of an aluminium additive (sulphate), to increase the SO 2 trapping efficiency in flue gas desulphurisation (FGD) systems, results in significant differences in the speciation and partitioning of elements between the aqueous and solid phases of gypsum slurries from two Spanish coal-fired power plants (PP1 and PP2). The Al-additive increases...
This study evaluates the environmental and thermodynamic performance of six coal-fired power plants with CO 2 capture and storage. The technologies examined are post-combustion capture using monoethanolamine, membrane separation, cryogenic fractionation and pressure swing adsorption, pre-combustion capture through coal gasification, and capture performing conventional oxy-fuel combustion....
The most critical problems to overcome in the PEM (proton exchange membrane) fuel cell technology are the water management. In this work, a seven-layer theoretical model is proposed that includes anode and cathode inlet channels, anode and cathode GDLs (gas diffusion layers), CLs (catalyst layers), and the 117 Nation proton exchange membrane. The mathematical model is a one-dimensional, steady-state,...
In the present study, the power consumption in a stirred vessel by two-blade impeller has been investigated. 3D finite volume based computational fluid dynamics (CFD) simulations have been carried out. The tank used has a cylindrical shape with a flat bottom. The liquid height was kept equal to the vessel diameter. Study has been restricted to the laminar regime with Newtonian and shear thinning fluids,...
Development of electrocatalytic materials for the hydrogen evolution reaction (HER) is attempted with the aim of reducing the water electrolysis overpotential and increasing its efficiency. Using linear scan voltammetry measurements of the hydrogen discharge enables evaluation of the electrocatalytic activity for the HER of platinum–dysprosium (Pt–Dy) intermetallic alloy electrodes of different compositions...
A novel technique for solving a dynamic optimal chiller loading problem is presented. This method reduces the complexity of the dynamic problem by considering all chillers to be a single, optimal chiller, which significantly reduces the number of decision variables. A static optimal chiller loading problem is solved as a sub-problem to give the optimal total power required at each time interval. The...
DMFC (direct methanol fuel cell) systems usually employ two pumps for supplying the methanol solution. The conventional system configuration, however, may bring about free flow from the methanol reservoir and malfunctions in the self-priming of the pumps. When instruments such as check valves and pressure regulators are applied, they result in excessive weight and control system malfunctions. In this...
A hybrid power control system is proposed in the paper, consisting of solar power, wind power, and a diesel-engine. To achieve a fast and stable response for the real power control, an intelligent controller was proposed, which consists of the Wilcoxon (radial basis function network) RBFN and the improved (Elman neural network) ENN for (maximum power point tracking) MPPT. The pitch angle control of...
This paper reports experimental testing of an adsorption dishwasher employing different desiccants, such as 13X zeolite, microporous silica gel and SAPO-34 zeolite. Thermodynamic comparison of the selected adsorbents was carried out on the basis of the experimental measurement of the main thermo-physical parameters, such as specific heat, adsorption equilibrium curves and sorption enthalpy.A sensitivity...
Generation expansion planning is defined as the problem of finding the technology type, number of generation units, size, and location of candidate plants within the planning horizon. In the deregulated environment rather than the traditional system which considered the cost minimization as the main objective function in generation expansion planning problem, the major objective is to maximize the...
This paper discusses time series approaches, often used by Transmission System Operators (TSOs) to forecast system demand, and applies them at an individual dwelling level. In particular, two techniques, Fourier transforms and Gaussian processes were evaluated and used to characterise individual household electricity demand. The performance of the characterisation approaches were evaluated based on...
This paper develops a simulated annealing based multi-objective cultural differential evolution (SA-MOCDE) for solving daily hydrothermal operation scheduling with economic emission (SHOSEE) while considering water transport delay and transmission loss of system load, and it is formulated for optimizing thermal cost and emission issue with complex non-convex constraints. The simulated annealing technique...
Life-cycle fossil primary energy consumption (FPEC) and greenhouse gas (GHG) emission intensity of nine types of dominant secondary energy (SE) pathways for China in 2010 are calculated with iterative methods, using the TLCAM (Tsinghua Life-cycle Analysis Model). Three major types of GHG (CO 2 , CH 4 and N 2 O) are considered for GHG emission intensity, and non-combustion CH...
Brassica napus L. (canola/oilseed rape) straw presents a suitable alternative combustion fuel due to its availability, relatively high calorific value and low moisture content. Pelletization enabled the bulk density of canola straw to be improved, enhancing its potential as an alternative combustion fuel. The aim of the paper was to determine the effect of on-farm storage on the gross calorific value,...
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