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Computer model of combustion and radiation processes in refuse derived fuel fired stoker boilers /Kadunc, Donald Albert January 1981 (has links)
No description available.
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A technique to incorporate the impacts of demand side management on generation expansion planningRinaldy 20 October 2005 (has links)
Demand Side Management (DSM) has begun to emerge as a major component of utility planning, with more utilities than ever before using it to help meet their own needs and those of their customers. DSM encompasses utility and customer activities aimed at modifying load shape, which embodies the timing and level of customer electricity demand. Future load shapes will result from the combined effect of individual DSM programs seeking specific load shape objectives. Load Duration Curve (LDC) is the vehicle through which DSM impacts are incorporated into power system planning and operation. Models of the LDC is one of the most important tools in the analysis of electric power system. The DSM will affect the peak load, the base load and total energy demand of the load duration curve. Those three impacts have to be explicitly modeled into the load duration curve for properly representing the effects of demand side management activities. However, the available models cannot properly represent the impacts of demand side management into load duration curve, because they do not explicitly model those three variables into their load duration curve. A new model that can incorporate the effects of demand side management is needed by utilities to help them with planning and operation. A new way to directly model the inverted load duration curve (ILDC) is presented in this study thus facilitating the representation of DSM impacts.
Peak Load, base load and total energy demand are the variables of the new model. Using DSM activities as case studies, the new model produced good results compared to other widely used models, in term of reliability indices (LOLP and ENS) and total energy under the load duration curve. The flexibility, simplicity and the speed of execution of the new model in calculating the reliability indices are demonstrated. The capability of the new model to calculate the capacity credit is also presented. As a result of its ability to represent energy under load duration curve, the new model is inserted into WASP computer program to calculate the production cost. Results obtained from the new model (modified WASP) compared to results from original WASP are very close. Based on these capabilities it can be claimed that the new ILDC model is a better overall model and can be used as an alternative load model in utility planning and operation. / Ph. D.
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Unit commitment for operationsSheblé, Gerald B. January 1985 (has links)
The topic of unit commitment has been and continues to be of interest to many researchers and is a primary operation for most utilities. Past research has utilized integer programming, dynamic programming, linear programming, gradient, and heuristic techniques. This research combines both linear programming and dynamic programming for unit commitment decisions within a weekly time frame. The result provides most of the advantages of linear programming and dynamic programming with less stringent requirements on the pre solution information needed for unit transition sequences. Further, the research yields a new tool for the solution of the Transaction Evaluation problem. / Ph. D. / incomplete_metadata
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Symbolic and connectionist machine learning techniques for short-term electric load forecastingRajagopalan, Jayendar 22 August 2009 (has links)
This work applies connectionist neural network learning techniques and symbolic machine learning techniques to the problem of short-term electric load forecasting. The short-term electric load forecasting problem considered here is the prediction of bus loads one day ahead. The forecast quantities of interest are average integrated daily load and daily peak load.
The primary objectives of this work are two-fold: to determine the forces driving the load demand and produce a human intelligible model, and use of this model to forecast load for new, unseen scenarios.
In the first part of this work, connectionist techniques for modeling bus load is presented. Critical design issues for neural network modeling and implementation such as neural network architecture, training database creation, training dataset selection, training data normalization are presented in context of nonlinear modeling in general and electric load forecasting in particular. Local function approximation and nearest neighbor norms techniques are applied to this task. Simulations are performed for forecast of average bus loads of the town of Blacksburg, Virginia, U.S.A; the connectionist model is able to forecast integrated average daily load with an accuracy of about 2.5%. Connectionist neural network knowledge acquisition algorithms are however, not mature enough, presently, to handle complex real world problems such as knowledge extraction from large databases. Presence of symbolic along with numeric data in input and output poses problems for data pre-processing for neural network training. Only at the time of completion of this thesis are researchers discussing the possibility of using special techniques to present symbolic data for neural networks. Also, multilayer feedforward networks trained by the backpropagation algorithm perform poorly in forecasting chaotic patterns such as those encountered in peak load demand.
Symbolic machine learning techniques are powerful concept acquisition techniques that extract underlying knowledge from large databases. They are sufficiently powerful to accept symbolic and numeric data. Inductive learning algorithms employing a statistical 72 test as the splitting criterion are applied to extract load dependency information. The extracted patterns are expressed as graphic decision trees and equivalent human intelligible high level language if-then rules. Implementation details of the statistical decision algorithm are discussed and simulations are performed to construct decision trees. Using this model, new cases are forecast. This algorithm is capable of forecasting holiday and weekend loads too. The proposed algorithm is robust enough to handle raw, unprocessed databases which contain missing data. The peak load forecasting problem is solved using a simple methodology that combines the robustness of decision trees and the numerical accuracy of connectionist models.
The two paradigms, connectionist and symbolic learning techniques are compared from a knowledge acquisition and forecasting perspective and directions for further work suggested. / Master of Science
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Real time data acquisition for load managementGhosh, Sushmita 15 November 2013 (has links)
Demand for Data Transfer between computers has increased ever since the introduction of Personal Computers (PC). Data Communicating on the Personal Computer is much more productive as it is an intelligent terminal that can connect to various hosts on the same I/O hardware circuit as well as execute processes on its own as an isolated system.
Yet, the PC on its own is useless for data communication. It requires a hardware interface circuit and software for controlling the handshaking signals and setting up communication parameters. Often the data is distorted due to noise in the line. Such transmission errors are imbedded in the data and require careful filtering.
The thesis deals with the development of a Data Acquisition system that collects real time load and weather data and stores them as historical database for use in a load forecast algorithm in a load management system. A filtering technique has been developed here that checks for transmission errors in the raw data. The microcomputers used in this development are the IBM PC/XT and the AT&T 3B2 supermicro computer. / Master of Science
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Knowledge-based and statistical load forecast model development and analysisMoghram, Ibrahim Said January 1989 (has links)
Most of the techniques that have been applied to the short-term load forecasting problem fall within the time series approaches. The exception to this has been a new approach based on the application of expert systems. Recently several techniques have been reported which apply the rule-based (or expert systems) approach to the short-term load forecasting problem. However, the maximum lead time used for these forecasts has not gone beyond 48 hours, even though there is a significant difference between these algorithms in terms of their data base requirements (few weeks to 10 years).
The work reported in this dissertation deals with two aspects. The first one is the application of rule-based techniques to weekly load forecast. A rule-based technique is presented that is capable of issuing a 168-hour lead-time load forecast. The second aspect is the development of a comprehensive load forecasting system that utilizes both the statistical and rule-based approaches. This integration overcomes the deficiencies that exist in both of these modeling techniques.
The load forecasting technique is developed using two parallel approaches. In the first approach expert information is used to identify weather variables, day types and diurnal effects that influence the electrical utility load. These parameters and hourly historical loads are then selectively used for various statistical techniques (e.g., univariate, transfer function and linear regression). A weighted average load forecast is then produced which judiciously combines the forecasts from these three techniques. The second approach, however, is free of any significant statistical computation, and is based totally on rules derived from electric utility experts. The data base requirement for any of these approaches do not extend more than four weeks ol hourly load, dry bulb and dew point temperatures. When the algorithms are applied to generate seven-day ahead load forecasts for summer (August) and winter (February) the average forecast errors for the month come under 3%. / Ph. D.
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Comparative Chemistry of Thermally Stressed North Lake and Its Water Source, Elm Fork Trinity RiverSams, Barry L. 12 1900 (has links)
To better understand abiotic dynamics in Southern reservoirs receiving heated effluents, water was analyzed before and after impoundment in 330 ha North Lake. Macronutrients, metals, and chlorinated hydrocarbons were measured. Concentrations of nutrients and metals in sediments were quantified in this 2 yr study. River water prior to impoundment contained 16 times more total phosphorus, and supported 23 times more Selenastrum capricornutum cells in an algal assay than reservoir water. The reservoir has essentially no drainage and since evaporation is high, the concentrations of many dissolved solids have increased since the reservoir was filled in 1958. North Lake is now phosphorus limited. Apparently altered chemical equilibria have caused precipitation or adsorption of phosphorus with calcium and iron.
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Resource Information Applied to Water Sources and Discharges at Existing and Potential Power Plant Sites in Arizona and the Southwest: Project Completion ReportDeCook, K. J., Fazzolare, R. A. January 1977 (has links)
Project Completion Report, OWRT Project No. A-043-ARIZ / Agreement No. 14-31-0001-4003 / Project Dates: July 1973 - June 1974 / Acknowledgment: The work upon which this report is based was supported in large part by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964. / A growing demand for energy production in Arizona has increased the need for assembling and analyzing water resource information relative to energy production, especially electrical power generation. Unit water requirements for cooling of electrical plants, combined with projections of future electrical power demands in Arizona, provide a perspective on future quantities of water needed for cooling.
Probabilistic estimates of storage reserves in Arizona groundwater basins indicate that some prospective plant sites can be supplied from groundwater for the 30 -year life of the plant, while others cannot. An estimate of comparative cost for supplying groundwater versus municipal wastewater for cooling electrical plants at selected sites in Arizona showed that use of wastewater would result in considerable savings over use of groundwater, at all sites considered.
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Perimeter fan performance in forced draught air-cooled steam condensersVan der Spuy, Sybrand Johannes 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Axial flow fan arrays form part of air-cooled steam condensers in direct drycooled
power plants. This dissertation investigates the performance of axial flow
fans when located at the perimeter of a fan array. The perimeter (or edge) fans
may experience a reduction in air flow through the fan due to the prevalence of
distorted inlet conditions upstream of the fan. The reduction in air flow leads to a
reduction in the heat transfer capability of the steam condenser and a consequent
reduction in the electricity output of the power plant.
Due to the physical size of an air-cooled condenser, full-scale experiments are
often impractical and computational fluid dynamics (CFD) is used to model its
performance under various conditions. To limit the size of the CFD model the
axial flow fans in the CFD analysis are represented by means of simplified
methods. Three different simplified methods are presented and applied to a CFD
model of a single axial flow fan, namely the pressure jump method (PJM),
actuator disc method (ADM) and extended actuator disc method (EADM). The
results are compared to experimental values. The comparison highlights the
limitations of the models: The ADM fails to model fan performance correctly at
low flow rates, while the PJM ignores the variation in fan blade properties at
different locations within the fan rotor. The EADM is presented as an
improvement on both the other two models.
A multiple fan test facility is constructed, consisting of three 630 mm diameter
fans extracting air from a common inlet chamber. The inlet chamber is
constructed in such a way that one of the three fans act as the perimeter (edge)
fan. The floor of the inlet chamber can be adjusted to increase or reduce the inlet
flow distortion experienced by the edge fan. Six different fan configurations are
tested in the position of the edge fan and an empirical method is derived by which
the volumetric effectiveness of an edge fan can be predicted. The experimental
results are compared to CFD results for the same facility using the three different
simplified simulation methods investigated previously. Particle image velocimetry
(PIV) measurements are also performed upstream of the edge fan and the velocity
profiles at the inlet of the fan are compared to the profiles obtained numerically.
The comparisons show that the EADM predicts the performance of the edge fan
more accurately than the ADM en PJM.
The effect of adding a walkway and removing the bell mouth upstream of the
edge fan was investigated using the EADM. The results are used to show the
location of the loss mechanisms upstream of the edge fan. The addition of a
walkway moves the location of the pressure loss away from the edge fan bell
mouth towards the edge of the walkway. Consequently the distortion directly
upstream of the edge fan is reduced and its volumetric effectiveness increased.
The effect of removing the edge fan’s bell mouth is similar to the effect of adding
a walkway upstream of the edge fan. / AFRIKAANSE OPSOMMING: Aksiaalwaaiermatrikse vorm deel van lugverkoelde kondensors in direk droëverkoelde
kragstasies. Hierdie verhandeling ondersoek die werkverrigting van
aksiaalwaaiers wat geleë is op die rand van ‘n groot waaiermatriks. Die
randwaaiers kan ’n vermindering in deurvloei ondervind as gevolg van versteurde
inlaattoestande stroom-op vanaf die waaier. Die vermindering in lugvloei lei tot ’n
vermindering in die warmetoordagvermoë van die stoomkondensor en ’n
gepaardgaande afname in die elektrisiteitslewering van die kragstasie.
As gevolg van die fisiese grootte van die lugverkoelde kondensor is volskaalse
eksperimente gewoonlik onprakties en word berekeningsvloeimeganika (BVM)
gebruik om die werking van die aanleg onder verskeie toestande te modelleer. Ten
einde die grootte van die BVM model te beperk, word die aksiaalwaaiers in so ‘n
BVM analiese voorgestel met behulp van vereenvoudigde metodes. Drie
verskillende vereenvoudigde metodes word aangebied en toegepas op ‘n BVM
model van ‘n enkelwaaier, naamlik die druksprongmetode, die aksieskyfmetode
en die verlengde aksieskyfmetode. Die resultate word vergelyk met
eksperimentele waardes. Die vergelyking benadruk die beperkings van die
modelle: Die aksieskyfmetode kan nie die werking van die waaier akkuraat
voorspel by lae vloeie nie en die druksprongmetode ignoreer die variasie in
lemeienskappe op verskillende liggings binne-in die waaierrotor. Die verlengde
aksieskyfmetode word voorgestel as ‘n verbetering op die ander twee metodes.
‘n Veelvuldige waaiertoetsfasiliteit is saamgestel, bestaande uit drie 630 mm
deursnee waaiers wat lug uit ’n gemeenskaplike inlaatkamer suig. Die inlaatkamer
is so saamgestel dat een van die waaiers in die fasiliteit ‘n randwaaier
verteenwoordig. Die vloerhoogte van die inlaatkamer kan aangepas word om die
inlaatversteuring wat deur die raandwaaier ondervind word te vermeerder of te
verminder. Ses verskillende waaierkonfigurasies is getoets in die
randwaaierposisie. ‘n Empiriese metode waarmee die volumetriese effektiwiteit
van ‘n randwaaier voorspel kan word is afgelei. Die eksperimentele resultate word
vergelyk met ooreenstemmende BVM resultate vir dieselfde fasiliteit deur gebruik
te maak van die drie verskillende vereenvoudigde metodes wat vroeër ondersoek
is. Partikelbeeld snelheidsmetings word ook stroom-op vanaf die randwaaier
uitgevoer en die snelheidsprofiele by die inlaat van die waaier word vergelyk met
profiele wat numeries bereken word. Die vergelykings wys dat die verlengde
aksieskyfmetode die werkverrigting van ’n aksiaalwaaier meer akkuraat voorspel
as die aksieskyf- of druksprongmetodes.
Die effek van die installering van ‘n loopvlak en die verwydering van die
randwaaier se inlaatmondstuk word ondersoek met behulp van BVM deur gebruik
te maak van die verlengde aksieskyfmetode. Die resultate word spesifiek gebruik
om die ligging van die verliesmeganismes stroom-op vanaf die randwaaier aan te
dui. Die resultate wys dat die installering van ‘n loopvlak die ligging van die
drukverlies wegneem vanaf die rand van die waaierinlaat na die rand van die
loopvlak. Dit verminder die inlaatversteuring stroom-op vanaf die randwaaier en die volumetriese effektiwiteit word verhoog. Die verwydering van die randwaaier
se inlaatmondstuk het ‘n soortgelyke effek as die installering van ‘n loopvlak
stroom-op vanaf die randwaaier.
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Air-cooled heat exchangers and cooling towers : thermal-flow performance evaluation and designKroger, Detlev G. 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: During the last 30 years I have been involved in the theory and practice of thermal engineering and
in particular, in the areas of air-cooled heat exchangers and cooling towers for the power,
refrigeration, process and petrochemical industries in South Africa and internationally. During this
period, I have authored and co-authored more than 120 papers that were published in technical
journals or presented at conferences nationally or internationally. Most of these papers are included
in a manuscript entitled "Air-cooled Heat Exchangers and Cooling Towers", in which Ipresent a
systematic approach to the thermal performance evaluation and design of industrial air-cooled heat
exchangers and cooling towers. This original publication also includes the relevant practice
applicable to the design of cooling systems, based on my experience as a consultant to industry.
Design offices throughout the world presently follow our design methods, or at least employ many
of our research results. Our work has furthermore contributed to the development of improved
cooling system designs (e.g. new dephlegmator header designs), components (e.g. single-row
flattened finned tubes) and product improvement and quality control (e.g. performance testing and
measurement of thermal contact resistance between fin and tube during production). Many of our
research findings have found application in the modification of existing cooling systems. The
manuscript has also been used as reference work during the presentation of short courses to
practising engineers and consultants in industry and to engineering graduates at the University of
Stellenbosch.
A two-volume edition of this manuscript was published by PennWell Corp., Tulsa, Oklahoma, USA
in 2004. / AFRIKAANSE OPSOMMING: Gedurende die laaste 30 jaar was ek betrokke by die teorie en praktyk van lugverkoelde warmteoordraers
en koeltorings vir die kragopwekkings-, verkoelings-, proses- en petro-chemiesenywerhede
in Suid-Afrika sowel as in die buiteland. Gedurende hierdie periode was ek outeur en
mede-outeur van meer as 120 publikasies wat in tegniese tydskrifte, of by plaaslike of oorsese
konferensies aangebied is. Die meeste van hierdie publikasies vorm deel van 'n manuskrip getiteld
"Air-cooled Heat Exchangers and Cooling Towers" waarin ek 'n sistematiese benadering tot die
bepaling van die termiese vermoë en ontwerp van industriële lugverkoelde warmteoordraers en
koeltorings aanbied. Hierdie oorspronklike publikasie bevat ook die relevante praktyk wat van
toepassing is op verkoelingsaanlegte. Ontwerpkantore wêreldwyd volg tans hierdie
ontwerpsmetodes, of gebruik ten minste baie van ons navorsingsresultate. Ons werk het verder
bygedra tot die ontwikkeling van verbeterde verkoelingsaanlegte (bv. nuwe deflegmatore),
komponente (bv. enkelbuisry platvinbuise ) en verbeterde produkte en kwaliteitskontrole
(bv. toetsing van verkoelingsvermoë oftermiese kontakweerstand tussen vin en buis gedurende
produksie). Baie van ons bevindinge het toepassing gevind in die modifikasie van
verkoelingsaanlegte. Die manuskrip is ook as verwysing gebruik gedurende die aanbieding van
kort kursusse aan ingenieurs in die praktyk en aan nagraadse studente aan die Universiteit van
Stellenbosch.
'n Twee-volume uitgawe van die manuskrip is deur PennWell Corp., Tulsa, Oklahome, VSA in
2004 gepubliseer.
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