Naim Afgan

Multi-criteria assessment of new and renewable energy power plants

The multi-criteria evaluation of new and renewable technologies demonstrates the potential analysis of complex systems. Every energy system under consideration is an entity by itself, defined by the respective number of parameters which are deterministically interrelated according to the physical laws. Sustainability indicators take into account the economic and environmental resources parameters. This paper presents selection of criteria and options for the new and renewable energy technologies assessment based on the analysis and synthesis of parameters under the information deficiency method. In order to present an evaluation of the new energy technologies, a number of options featuring some of the characteristics measured by the selected sustainability indicators are taken into consideration. For each option under consideration, the sustainability indicators are defined in order to verify their rating under the specific constraints and to obtain the generalised index of sustainability rating of all options. The aim of this paper is to define energy indicators used in the assessment of energy systems which meet the sustainability criterion. In this respect, the following indicators are taken into consideration: energy resources, environment capacity, social indicators and economic indicators.

Energy system assessment with sustainability indicators

Abstract The paper presents an attempt to select, define and apply a set of sustainability indicators for the energy system assessment. Starting from the general sustainability concept, a set of indicators is defined reflecting specific criteria for the energy system evaluation. Particular attention is devoted to the resource, environment, social and economic criteria. Among these groups of criteria there are individual indicators emphasising respective aspect of the sustainability concept. This approach has its limitation due to the lack of data for serious consideration of the system. But it should be anticipated that these excises might serve as the guidance for the eventual future application. Also, this methodology for the assessment of energy system will become an useful tool only if it proves useful in the engineering practice. The example under consideration is an island with only individual consumption to be satisfied with solar, wind, biomass and oil-fired power plant which represent four options under consideration. The set of indicators is defined and determined with the aim to demonstrate the method of decision making procedure in selecting the option which meet selected indicators numerical values and constrain reflecting the non-numeric information of weighting factor for the determination of general criteria for the selection of appropriate option.

Sustainable Energy Development

In order to reach the goals indicated by the sustainable energy development the efficiency in the energy conversion use has to meet several criterions [1]. The potential for the efficiency improvement is generally underestimated. Most of the energy conversion systems consider the efficiency improvement as a separate process and their analysis reflects only the potential improvement of the process but not the potential for the efficiency improvement obtained by an exergy analysis of the energy system. Fossil fuel energy resources use is mostly conversion to heat by the combustion processes. Since the combustion process is taking place at temperatures between 900 — 1300°C and over 40% of heat is used a low temperature heat, it is indispensable to take into consideration the thermodynamic assessment of the efficiency in order to bring in line energy conversion processes and energy demand to obtain the optimum fuel utilization.

Sustainability assessment of desalination plants for water production

The paper presents an attempt to assess sustainability of desalination plants for water production based on resource, environmental and economic indicators. Four types of desalination plants are taken into a consideration: single MSF, dual purpose MSF, RO with local energy consumption and RO with PV electric energy production. The analysis is based on data from desalination plants in Gulf countries. In particular, it reflects water production demand and energy sources used for the individual plants. The decision-making procedure in the sustainability assessment of desalination plants is based on the multi-criteria evaluation under uncertainty of complex systems expressed by the General Sustainability Index. Evaluation of different cases reflecting priority of the criteria for evaluation has led to the selection of options, which are in compliance with respective criteria.

A radiation and convection fluxmeter for high temperature applications

Heat flux is an essential parameter for the diagnostic of thermal systems. In high temperature industrial environment, there are diAculties in measuring incident radiation heat flux as well as in diAerentiating between the convective and radiative components of heat flux on the heat transfer surface. A new method for heat flux measurement is being developed using a porous sensing element. The gas stream flowing through the porous element is used to measure the heat received by the sensor surface exposed to the hot gas environment. A numerical model of sensor with appropriate boundary condition has been developed in order to perform analysis of possible options regarding its design. The analysis includes: geometry of element, physical parameters of gas and solid and gas flow rate through the porous element. For the optimal selection of parameters, an experimental set-up was designed, including the sensor element with respective cooling and monitoring systems and a high temperature radiation source. The experimental set-up was used to obtain calibration curves for a number of sensors. The linear dependency of the heat flux and respective temperature diAerence of the gas were verified. The accuracy analysis of the sensor reading has proved high linearity of the calibration curve and accuracy of 5%. ” 2000 Elsevier Science Inc. All rights reserved.

Boiler tube leakage detection expert system

Abstract Efficient and reliable operation is the main requirement of the modern power plant. The most probable reason for failure in the power plant boiler is tube leakage. It is usually detected when urgent action is needed to prevent accidents in the plant. Advance detection of boiler leakage is of primary interest to secure maintenance planning and prevent the adverse effect of tube rupture. The development of the tube failure detection system is a demanding issue for the large power plant boilers. The present paper describes the development of an expert system for detecting boiler tube leakage. The system is based on selected diagnostic variables obtained by radiation heat flux measurements. A sensitivity analysis of the diagnostic variables is performed. A three-dimensional mathematical model of the boiler furnace is used to obtain the confidence level for the minimum leakage to be detected. The design of the expert system is based on relative values of the radiation flux reading as the diagnostic parameter. The leakage detection expert system is designed in the knowledge base environment, comprising the knowledge base containing facts, information on how to reason with these facts and inference mechanisms able to convert information from the knowledge base into user requested information. The knowledge base is based on the object-oriented structure with the definition of the object LEAKAGE. The object class LEAKAGE is composed of subclasses SENSOR and CASES. The inference procedure uses a set of procedural processes in the preparation of diagnostic variables reading for the decision making process. A fuzzification process is used for conversion of actual diagnostic values into semantic values. The several steps of the inference procedure lead to the logic processing of individual and collective representation of diagnostic variables represented in the knowledge base. A number of examples are given for leakage detection based on the expert system reasoning and monitoring representative situations which are imminent to the set of parameters describing situations preceding boiler tube rupture.

Biomass-fired power plant : the sustainability option

Abstract Biomass use for power generation has become an attractive option for the increase of energy production with the increase of efficiency, decrease of environment degradation and waste utilization. Justification of the biomass use benefits requires a multi-criteria assessment based on the evaluation of economic, environmental, technological and social aspects. In this respect, the need for the evaluation of biomass-fired power plant is of great interest for the validation of benefits of biomass resources. The paper presents an outline of a multi-criteria method for the evaluation of the General Sustainability Index as the quality measurement of different potential options of the biomass-fired power plant and their comparison with other new and renewable power plants. A number of options are evaluated with appropriate selection of indicators reflecting economic, environment, technological and social parameters. Among options under consideration there are those reflecting mixed fuel of biomass and fossil organic fuel power plants. Special attention is devoted to the use of constraints giving priority to individual criteria. It is shown that the potential quality merit, which describes the priority of individual options under specific constraint is the potential tool for the energy system evaluation. This decision-making procedure enlightens the potential priority of biomass-fired power plants in comparison with other renewable energy sources.

Sustainability Assessment of Renewable Energy Systems

The paper presents an attempt to select, define and apply the sustainability set of indicators for the energy system assessment. Starting from the general concept of sustainability it is defined the set of indicators reflecting specific criteria for the energy system evaluation. The particular attention is devoted to the resource, environment, social and economic criteria. Among these group of criteria there are individual indicators emphasising respective aspect of the sustainability concept. Obviously, this type of approach has its limitation due to the lack of data for the serious consideration of the system. But it should be anticipated that these excises might serve as the guidance for the eventual future application. Also, it should be emphasised that this type of methodology for the assessment of energy system will become useful tool only if it proves to be justified in the engineering practice. The example under consideration is an island with only individual consumption to be satisfied with solar, wind, biomass and oil fired power plant which represent four options under consideration. The set of indicators is defined and determined with the aim to demonstrate the method of decision making procedure in selecting the option which meet specified numerical values of selected indicators and constrain reflecting the non-numeric information of weighting factor for the determination of general criteria for the selection of appropriate option.

Knowledge-based expert system for fouling assessment of industrial heat exchangers

Abstract The paper emphasises the need for the development of the expert system as a tool for the mitigation of the fouling processes. Particular reference is given to the design margin lifetime assessment, fouling process control, fouling removal assessment and heat-exchanger safety by the expert system for industrial heat exchangers. This paper presents the concept of a heat-exchanger on-line system. The heat-exchanger efficiency is defined by the NTU concept for the simple parallel co-current heat exchanger. The respective methodology is used for the description of the generic behaviour of the heat-exchanger system. Particular attention was paid to the recognition of those situations leading to the degradation of the efficiency of the heat exchanger. The paper describes the selection of the diagnostic variables and their on-line measurements, including the logging system for the monitoring and acquisition of the data. The knowledge base is derived from the definition of the heat-exchanger efficiency. The approach presented is based on an object-attribute-value structured knowledge base. It includes hot and cold stream flow rate and hot and cold fouling thickness assessment. In this respect, particular attention was paid to the fouling process assessment and its effect on the efficiency degradation of the heat exchanger. For the specific heat exchanger, the expert system assessment of different situations was shown with this approach.

New and renewable technologies for sustainable development

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