The Experts below are selected from a list of 9267 Experts worldwide ranked by ideXlab platform
Sewon Oh - One of the best experts on this subject based on the ideXlab platform.
-
economic analysis of dry bottom ash handling system in a pulverized coal thermal power plant in korea ii case study for retrofitting the existing facility
Journal of the Korean Institute of Resources Recycling, 2005Co-Authors: Sewon OhAbstract:Economic feasibility for retrofitting the wet bottom ash handling system to the dry system in a existing 500MW2 units pulverized coal thermal power plant in Korea was studied. Replacing to the dry system requires the Initial Capital Costs of 13,415,127,000\, and saves the operating Costs of 935,345,000\ per year. Economic analyses based on these results showed that the Initial Capital Cost would not be recovered within the service life of the facilities at the interest rate of 10%, and the internal rate of return of 5.6% were obtained. Thus, the retrofitting to the dry system was not economically favorable in the current condition. However, the retrofitting would be profitable when the ash disposal Cost and ash selling price were increased over 15,000\/MT or 17,000\/MT, respectively.
-
economic analysis of dry bottom ash handling system in a pulverized coal thermal power plant in korea
Journal of the Korean Institute of Resources Recycling, 2004Co-Authors: Sewon OhAbstract:Economic benefits of the dry bottom ash handling system over the wet bottom ash handling system in a new 500MW2units pulverized coal thermal power plant in Korea were evaluated. The higher Initial Capital Cost in the dry bottom ash handling system was estimated. However, this higher Initial Capital Costs would be compensated with reductions of the operating Cost mainly due to the recycling of bottom ash. Economic analysis showed that the payback period of 4.9 years and the internal rate of return at 21.1% were expected for the additional Initial Capital Cost of the dry bottom ash handling system.
N F Tsagas - One of the best experts on this subject based on the ideXlab platform.
-
technoeconomic assessment of a hybrid solar wind installation for electrical energy saving
Energy and Buildings, 2003Co-Authors: G C Bakos, N F TsagasAbstract:This paper reports the technical feasibility and economic viability of a hybrid solar/wind grid connected system for electrical and thermal energy production, covering the energy demand of a typical residence in the city of Xanthi (Greece). The technical characteristics of the solar and wind energy subsystems are given. The energy output provided by the hybrid energy system was estimated using a simulation program, which is based on the Monte Carlo method, for reading the solar radiation and wind potential data. The auxiliary energy supply is based on the output of a combined-cycle natural gas power plant, recently constructed in the Thrace region. The economic analysis of the proposed hybrid solar/wind system is performed using the life cycle savings (LCS) method and the payback period (PBP) of the Initial Capital Cost is determined.
Edwards, John Riley - One of the best experts on this subject based on the ideXlab platform.
-
Quantification of prestressed concrete railway crosstie flexural response: Implications for mechanistic design
2021Co-Authors: Edwards, John RileyAbstract:Concrete is the dominant crosstie material choice for demanding locations on heavy axle load (HAL) freight railroads with steep grades, sharp curves, and high annual gross tonnage. Concrete crossties are also used in rail transit applications where safety and reliability of infrastructure is at a premium and maintenance time is often limited. As such, development and implementation of a structural design method that enables optimization of crosstie design for varied applications and loading environments will reduce Initial Capital Cost and recurring maintenance expense. Center flexural cracking is one of the most common factors limiting the service life of concrete crossties in North America, and rail seat cracking has been documented as a performance concern. Improving the understanding of crosstie flexure can help reduce the occurrences of cracked crossties by ensuring that designs conform to the field conditions in which they are used. To date, few methods have been proposed to accurately quantify the revenue service field bending moments of concrete crossties and their variability due to support conditions and other factors. This dissertation describes the development, deployment, and validation of a method to quantify crosstie bending moments using concrete surface strain gauges. Data collected using this method at field installations throughout the United States were used to investigate the effects of thermal gradient, axle load, axle location, support condition, and rail mode on crosstie bending moments. Results indicated that thermal gradient is significant and should be considered in crosstie flexural design, especially at the crosstie center. Additionally, crosstie support condition is the largest source of variability in crosstie bending moments and its effect is most pronounced on HAL freight railroads. The field results indicated the need for development and application of a probabilistic design method for the flexural capacity of concrete crossties. I developed a design process based on structural reliability analysis concepts whereby target values for reliability indices (β) for new designs are obtained and compared with existing designs for further design optimization. New (proposed) designs are more economical, having a center negative moment capacity reduction of 50% for heavy rail transit. For HAL freight, a reduction in rail seat bending capacity of approximately 40% is justified, reducing the size of the rail seat cross section by approximately the same magnitude. In most cases the proposed designs for both rail modes have fewer prestressing wires and a higher centroid of prestressing steel. In all cases the flexural capacities at the crosstie center and rail seat are better balanced from a structural reliability standpoint. The probabilistic method using structural reliability analysis fundamentals that is proposed and demonstrated in this dissertation constitutes a critical step in the development of mechanistic-empirical practices for the design of concrete crossties. Additionally, this framework for probabilistic design provides a foundation for the future application of mechanistic-empirical design practices to other railway track components.U of I OnlyAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD syste
-
Quantification of prestressed concrete railway crosstie flexural response: Implications for mechanistic design
2019Co-Authors: Edwards, John RileyAbstract:Concrete is the dominant crosstie material choice for demanding locations on heavy axle load (HAL) freight railroads with steep grades, sharp curves, and high annual gross tonnage. Concrete crossties are also used in rail transit applications where safety and reliability of infrastructure is at a premium and maintenance time is often limited. As such, development and implementation of a structural design method that enables optimization of crosstie design for varied applications and loading environments will reduce Initial Capital Cost and recurring maintenance expense. Center flexural cracking is one of the most common factors limiting the service life of concrete crossties in North America, and rail seat cracking has been documented as a performance concern. Improving the understanding of crosstie flexure can help reduce the occurrences of cracked crossties by ensuring that designs conform to the field conditions in which they are used. To date, few methods have been proposed to accurately quantify the revenue service field bending moments of concrete crossties and their variability due to support conditions and other factors. This dissertation describes the development, deployment, and validation of a method to quantify crosstie bending moments using concrete surface strain gauges. Data collected using this method at field installations throughout the United States were used to investigate the effects of thermal gradient, axle load, axle location, support condition, and rail mode on crosstie bending moments. Results indicated that thermal gradient is significant and should be considered in crosstie flexural design, especially at the crosstie center. Additionally, crosstie support condition is the largest source of variability in crosstie bending moments and its effect is most pronounced on HAL freight railroads. The field results indicated the need for development and application of a probabilistic design method for the flexural capacity of concrete crossties. I developed a design process based on structural reliability analysis concepts whereby target values for reliability indices (β) for new designs are obtained and compared with existing designs for further design optimization. New (proposed) designs are more economical, having a center negative moment capacity reduction of 50% for heavy rail transit. For HAL freight, a reduction in rail seat bending capacity of approximately 40% is justified, reducing the size of the rail seat cross section by approximately the same magnitude. In most cases the proposed designs for both rail modes have fewer prestressing wires and a higher centroid of prestressing steel. In all cases the flexural capacities at the crosstie center and rail seat are better balanced from a structural reliability standpoint. The probabilistic method using structural reliability analysis fundamentals that is proposed and demonstrated in this dissertation constitutes a critical step in the development of mechanistic-empirical practices for the design of concrete crossties. Additionally, this framework for probabilistic design provides a foundation for the future application of mechanistic-empirical design practices to other railway track components
B Mongey - One of the best experts on this subject based on the ideXlab platform.
-
an economic and technical case for a compressor expander unit for heat pumps
International Journal of Energy Research, 2000Co-Authors: P C Henderson, Neil Hewitt, B MongeyAbstract:Despite their obvious environmental benefit, heat pumps in general have difficulties in penetrating the heating market because of the high Initial Capital Cost. However, given the fact that in the U.K. space heating alone accounts for nearly 50 per cent of all the primary energy used, the universal adoption of heat pump subsidies similar to those offered by certain German utilities for example would be an effective contributor to the reduction of greenhouse gas emission. However, it would be improper for subsidies alone to be the only mechanism by which heat pumps could gain the scale of market acceptance necessary in order to make the required greenhouse gas emission cuts. Therefore, a new generation of heat pumps must have a superior performance than existing units operating with HCFC R22 or R407c. The use of R410a can aid heat pump market penetration by having heat pumps of a superior performance and a smaller size. However, to make full use of R410a, the difficulties of the relatively low critical point must be overcome and the use of a novel compressor/expander unit is illustrated. Copyright © 2000 John Wiley & Sons, Ltd.
Leyla Ozgener - One of the best experts on this subject based on the ideXlab platform.
-
Modeling of driveway as a solar collector for improving efficiency of solar assisted geothermal heat pump system: A case study
Renewable and Sustainable Energy Reviews, 2015Co-Authors: Onder Ozgener, Leyla OzgenerAbstract:It is well known that rooftop solar thermal panels increase both power rates of circulation pumps and Initial investment Cost of solar assisted ground source (geothermal) systems. To avoid both of them it means that the unnecessary energy consumption rates of circulation pump(s) and their Initial Capital Cost, rather than installing rooftop solar thermal panels, driveways can be used as solar collectors for improving efficiency of geothermal heat pump systems (GSHP) and declining Initial Capital Cost of SAGSHPs. Mainly this idea was first put in the middle by Jefferson W. Tester. In this paper, we will examine modeling of driveway as solar thermal panel to enhance efficiency of solar assisted geothermal heat pump system (SAGSHP) depends on its different operating types; yet we will give only a case that is investigated theoretically for solar assisted geothermal heat pump systems.