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To detect and alleviate harmonic resonance in a power system have been a delicate issue. In this paper, the effect of load modeling on resonance behavior of power systems employing eigenvalue sensitivity analysis is investigated. The most influencing parameters to mitigate resonance modes are detected using the sensitivity of critical eigenvalues with respect to the network various components in a...
This study addresses the problem of modeling the electricity demand loads in Greece. The provided actual load data is deseasonilized and an AutoRegressive Moving Average (ARMA) model is fitted on the data off-line, using the Akaike Corrected Information Criterion (AICC). The developed model fits the data in a successful manner. Difficulties occur when the provided data includes noise or errors and...
Several distributed triple-generation (DTG) system options to produce cooling, heating and power have been evaluated and compared in a multi-criteria method, such as technical, economic, environmental and social aspects. Due to the fuzzy or uncertain evaluation criteria, this paper presents an improved grey incidence evaluation method for DTG systems. This method adopts the combination of the improved...
Fe 3 O 4 supported on cubic yttria-stabilized zirconia (Fe 3 O 4 /c-YSZ) is proposed as a promising redox material for the production of hydrogen from water via a thermochemical two-step water-splitting cycle. In this study, the evolution of oxygen and hydrogen during the cyclic reaction was examined using Fe 3 O 4 /c-YSZ particles in order to demonstrate...
As a result of the increasing wind power penetration on power systems, the wind farms are today required to participate actively in grid operation by an appropriate generation control. This paper presents a comparative study on the performance of three control strategies for DFIG wind turbines. The study focuses on the regulation of the active and reactive power to a set point ordered by the wind...
Using the data for per capita carbon dioxide (CO 2 ) emissions relative to the average per capita emissions for 21 countries in the organisation for economic co-operation and development (OECD) covering the period 1960–2000, this paper seeks to determine whether the stochastic convergence and β-convergence of CO 2 emissions are supported in countries with the same level of development...
Improvements in energy efficiency and renewable energy use can reduce farm operating costs and reduce greenhouse gas (GHG) emissions. Responses (n=224, representing a 32% response rate) from a mail survey were used to assess use and interest in energy efficient and renewable energy options on farms in Nova Scotia, Canada. Energy efficiency options used the most were behavior, insulation, and lighting...
In this paper, an exergy cost analysis method based on the structural theory of thermoeconomics is applied to a gas-fired micro-trigeneration system, which uses a small-scale generator set driven by a gas engine and a new small-scale adsorption chiller (ADC). The thermoeconomic model for the system based on the fuel–product concept is defined to quantify the productive interaction between various...
Industrial waste materials, such as steelmaking slags, appear to be potential raw materials for reducing CO 2 emissions by carbonation. The suitability of applying a carbonation route based on acetic acid leaching to produce carbonates from blast furnace slag is presented in this study. The effect of solution pH, temperature, and CO 2 pressure on the precipitation of carbonates was...
Many computational fluid dynamics polymer-electrolyte-membrane fuel cell models have been presented over the last few decades. A detailed literature overview of models, ranging from one-dimensional, single-component to complete three-dimensional, large-scale setups, is presented with an emphasis on heat and mass transfer. Modeling strategies and commonly used assumptions are discussed. Solver implementations,...
At modest penetration, wind power merely substitutes electricity generated typically at thermal power plants. In this case, wind power only provides economic benefits in terms of saved marginal fuel and operation and maintenance costs. At higher penetrations, it becomes increasingly important for the energy system to be able to operate without costly reserve capacity awaiting fluctuations in demand...
Optimization studies along with optimum parameter correlations, using constant area mixing model are presented in this article for ejector-expansion transcritical CO 2 heat pump cycle with both conventional and modified layouts. Both the energetic and exergetic comparisons between valve, turbine and ejector-expansions-based transcritical CO 2 heat pump cycles are also studied for simultaneous...
A previously developed and validated zero-dimensional, multi-zone, thermodynamic combustion model for the prediction of spark ignition (SI) engine performance and nitric oxide (NO) emissions has been extended to include second-law analysis. The main characteristic of the model is the division of the burned gas into several distinct zones, in order to account for the temperature and chemical species...
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