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This paper deals with cost savings resulting from DSM, i.e. reductions in the number and cost of shut-downs and start-ups of generators. The proposed methodology applied to a test-data system yields savings of 28%. The total avoided costs are also estimated and it is pointed out on the basis of a total resource cost that the omission of these dynamic benefits can result in a bias against a DSM program...
Control of a wind power plant as an isolated power source is analyzed. The plant consists of a wind turbine (connected by means of a gear box to a three-phase synchronous electric generator) and a control system. Mathematical models of the wind turbine and electrical generator have been proposed. The one-step-ahead adaptive control technique has been adopted to govern the system. Results of a control...
Minimum efficiency standards for residential appliances have been implemented in the US for a large number of residential end-uses. This analysis assesses the potential energy, dollar, and carbon impacts of those standards at the state and national levels. We explicitly account for improvements in efficiency likely to occur in the absence of standards, but because our method for characterizing these...
In this paper, the Turkish energy production sector is studied and power plants fueled by natural gas, imported coal and nuclear power are compared in terms of long-term (1996-2010) production economy. A net present value model is used for comparing nuclear, coal and natural gas power plants. A scenario approach is utilized in establishing the effects of different factors, such as inflation rate,...
The photocatalytic reduction of CO 2 was investigated using TiO 2 powders in supercritical fluid CO 2 . These were irradiated in a stainless steel vessel at 9.0MPa and 35 o C. After reducing the CO 2 pressure to the ordinary state, pure water was added to the vessel while avoiding air contamination. No gaseous reduction products were observed. Formic acid was...
The gasification rate was measured of chunks of coal with a high content of volatiles, average size of 65x47x38 mm and an initial weight of 120+/-7 g. The influence of air temperature and velocity on the gasification rate was studied in a tubular experimental device. The time dependencies of the gasification rate and some gaseous species on air temperature and velocity were observed. A discontinuity...
Greenhouse-gas emission mitigation has been estimated for the use of existing and mature biomass technologies. A general methodology has been developed to determine potential amounts of residues that can be made available for energy purposes and the resulting fossil-fuel replacement from utilization of these residues. The consequent reductions in CO 2 , CH 4 and N 2 O emissions...
Remote underground water wells were investigated and 13 such wells were chosen for this study. Photovoltaic (PV) generators were used to power pumping the water up to the surface tanks to be used. A design method was established and illustrated depending on a pumping factor (F p ) which is a function of the solar characteristics. A laboratory solar water pumping unit was constructed and year...
The development and evaluation of cost-effective environmental strategies for the energy sector, based on energy-emission models for both national and international levels, requires consideration of the effects of energy-price changes on energy-service demand. To cope with the problem that the forms of functional dependencies between energy-service demand and independent variables are often unknown,...
The use of solar energy for growing cucumbers in pots and the ground has been studied under controlled environments in a solar greenhouse. Forced and evaporative cooling were employed. An average of 7 cucumbers per pot (1342.4 g) was produced. Linear and multiple regression analyses were used to analyze the data. Correlations are proposed for predicting the yield as a function of the number, length...
Improvements in productivity may be obtained if water vapor is carried away directly by flowing air. Humidities at the condensing surfaces and in the outlet air were assumed to differ from the saturation values by empirically determined factors. The effects of operating conditions on these factors are discussed.
The application of exergy (second-law) analysis to aquifer thermal energy storage (ATES) systems is investigated in order to facilitate proper assessments of overall system performances. An elementary ATES model is created, and the corresponding expressions are developed for efficiencies and for the quantities of energy and exergy that are injected and recovered. It is demonstrated that ATES performance...
Hazelnut shells were converted to charcoal and to liquid, and gaseous products using pyrolysis at different temperatures. The chemical compositions and yields of the charcoals were determined as functions of the carbonization temperature. Higher heating values (HHVs) were estimated using both ultimate and proximate analyses. Hazelnut shells and the derived charcoal were densified to briquettes using...
The phenomena of acoustical pressure oscillations generated in a gas by a steady heat source may be separated into two distinct types: (i) Sondhauss oscillations which occur in a pipe having one end closed and one open; (ii) Rijke oscillations which occur in a pipe with both ends open. After reviewing representative literature, actual and possible applications are described. Analogies and differences...
Grid-connected photovoltaic systems are required to introduce photovoltaic solar energy into urban areas. To analyze these systems, a 2.0 kW p power system has been installed at the University of Malaga, Spain. The array power output was estimated by using measured I-V curves for the installed modules with minimization of mismatch losses. The supplied grid energy and main performances are...
Following the oil crisis, most developed countries have increasingly implemented measures for energy conservation and fuels substitution aimed at decreasing the energy intensities of their economies. These efforts have been further augmented during the eighties due to growing awareness of adverse effects of energy use on the environment. The measures and their effectiveness differ greatly from country...
Two-phase flow of pure chlorofluorocarbon (CFC) refrigerants in solar collector tubes has been examined in previous studies in connection with applications in direct-expansion, solar-assisted heat pumps (DX-SAHP). The present work extends the thermodynamic analysis of solar collectors to the multicomponent and multiphase domain to cover newly proposed refrigerant mixtures which are potential candidates...
A three-phase model allows for bubble-size variations with height and yields the gas-phase species (O 2 , H 2 O, CO 2 and CO) distributions. The empirical value of fraction of the cloud-wake phase was found. Model predictions are compared with plant data and reasonable agreement is obtained.
Univariate Box-Jenkins time-series analyses (ARIMA models), were used for modeling and forecasting future energy production and consumption in Asturias. Initially, each series was recorded monthly from 1980 to 1996. These data include trend and seasonal variations which allow the use of ARIMA (AutoRegressive Integrated Moving Average) univariate models for predictions of future behavioral patterns...
In a recent paper published in this journal, Teng and Yamasaki presented an analysis of mass transfer from CO 2 droplets in Stokes flow of water for direct ocean disposal of CO 2 . Comparing the results of the analysis and some relevant experimental observations reported by other research groups, they developed a unique view of the mechanism of dissolution of CO 2 into water...
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