This study is concerned with the identification and utilisation of design solutions for improving the thermal environment of residential buildings in hot dry climates in general and the hot arid zone of Iran in particular. The influence of various energy conservation options on energy use in a prototype house has been analysed using the ESP dynamic computer simulation program. The research was aimed at providing a range of design guidelines for use in the process of building design by builders, architects and engineers. It also suggests programs relying on occupancy behaviour such as; thermostat settings or operating windows. The recommended design solutions are among those which can be obtained economically through the architectural application of commonly available construction materials and skills whilst also being appropriate in the socio-economic context in which the design and use of buildings take place. The effect of parameters such as; thermal mass and insulation, surface characteristics, orientation, window design, shading and environmental control strategies on the thermal performance of the prototype house has been investigated. Energy and comfort have been used as indicators of performance.

The rapid housing and building development in the Dammam region of Saudi Arabia has transformed the region into a progressive urban area. The contemporary buildings which have spread all over the region in a short period have failed to provide acceptable comfort conditions inside the house, leading to the widespread use of mechanical cooling systems. The combination of poor thermal design and the rise in electricity prices has resulted in high annual fuel bills for running the air conditioning systems. This study investigates the potential for energy conservation in residential buildings in Dammam region. It aims to identify the problem of high energy consumption in contemporary buildings and to study the relationship between the energy used and the thermal performance of the building. This study reviews the socio-economic characteristics of Dammam region's inhabitants and the traditional and contemporary building materials cooling systems used in the region. It also presents a survey analysis of 500 houses and provides a thermal comparison and assessment of six case study houses. A computer model has been developed and validated by the author to predict the annual amount of energy used in cooling the house. This model has been used to. predict the various energy savings that can be achieved by modifying the building envelope • elements and using lower U-values. Finally, some recommendations have been derived from the analysis.

With the increased loading and exploitation of the power transmission system and also due to improved optimised operation, the problem of voltage stability and voltage collapse attracts more and more attention . A voltage collapse can take place in systems or subsystems and can appear quite abruptly. Continuous monitoring of the system state is therefore required. The cause of the 1977 New York black out has been proved to be the reactive power problem. The 1987 Tokyo black out was believed to be due to reactive power shortage and to a voltage collapse at summer peak load. These facts have strongly indicated that reactive power planning and dispatching play an important role in the security of modern power systems. A proper compensation of system voltage profiles will enhance the system securities in the operation and will reduce system losses. In this thesis, some aspects of reactive power dispatch and voltage control problem have been investigated. The research has focused on the following three issues: Firstly, the steady-state stability problem has been tackled where, a voltage collapse proximity indicator based on the optimal impedance solution of a two bus system has been generalised to an actual system and the performance of this indicator has been investigated over the whole range (stable and unstable region) to see how useful this indicator can be for an operator at any operating point. Then we went further to implement a linear reactive power dispatch algorithm in which this indicator was used for the first time to attempt to prevent a voltage collapse in the system. Secondly, a new efficient technique for N-1 security has been incorporated aiming at either maximising the reactive power reserve margin for the generators or minimising active power losses during normal as well as outage conditions (single line outage) .The reactive power redistribution after an outage is based on the S-E graph adopted by Phadke and Spong[72].Thirdly, the dispatch (N-1 security excluded) has been incorporated on line in the O.C.E.P.S. control package to improve the quality of the service and system security by optimally controlling the generator voltages (potentially the reactive control system is able to control transformers, switchable capacitors and reactors). A new function called load voltage control (similar to the load frequency control function) has been introduced to allow smooth variation of the reactive control signals towards their targets.

The present day digital computing resources are overburdened by the amount of calculation necessary for power system dynamic simulation. Although the hardware has improved significantly, the expansion of the interconnected systems, and the requirement for more detailed models with frequent solutions have increased the need for simulating these systems in real time. To achieve this, more effort has been devoted to developing and improving the application of numerical methods and computational techniques such as sparsity-directed approaches and network decomposition to power system dynamic studies. This project is a modest contribution towards solving this problem. It consists of applying a very efficient sparsity technique to the power system dynamic simulator under a wide range of events. The method used was first developed by Zollenkopf (^117) Following the structure of the linear equations related to power system dynamic simulator models, the original algorithm which was conceived for scalar calculation has been modified to use sets of 2 * 2 sub-matrices for both the dynamic and algebraic equations. The realisation of real-time simulators also requires the simplification of the power system models and the adoption of a few assumptions such as neglecting short time constants. Most of the network components are simulated. The generating units include synchronous generators and their local controllers, and the simulated network is composed of transmission lines and transformers with tap-changing and phase-shifting, non-linear static loads, shunt compensators and simplified protection. The simulator is capable of handling some of the severe events which occur in power systems such as islanding, island re-synchronisation and generator start-up and shut-down. To avoid the stiffness problem and ensure the numerical stability of the system at long time steps at a reasonable accuracy, the implicit trapezoidal rule is used for discretising the dynamic equations. The algebraisation of differential equations requires an iterative process. Also the non-linear network models are generally better solved by the Newton-Raphson iterative method which has an efficient quadratic rate of convergence. This has favoured the adoption of the simultaneous technique over the classical partitioned method. In this case the algebraised differential equations and the non-linear static equations are solved as one set of algebraic equations. Another way of speeding-up centralised simulators is the adoption of distributed techniques. In this case the simulated networks are subdivided into areas which are computed by a multi-task machine (Perkin Elmer PE3230). A coordinating subprogram is necessary to synchronise and control the computation of the different areas, and perform the overall solution of the system. In addition to this decomposed algorithm the developed technique is also implemented in the parallel simulator running on the Array Processor FPS 5205 attached to a Perkin Elmer PE 3230 minicomputer, and a centralised version run on the host computer. Testing these simulators on three networks under a range of events would allow for the assessment of the algorithm and the selection of the best candidate hardware structure to be used as a dedicated machine to support the dynamic simulator. The results obtained from this dynamic simulator are very impressive. Great speed-up is realised, stable solutions under very severe events are obtained showing the robustness of the system, and accurate long-term results are obtained. Therefore, the present simulator provides a realistic test bed to the Energy Management System. It can also be used for other purposes such as operator training.

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A planned development of the electricity supply system in the Maltese Islands is presented. The purpose of this project was to develop techniques for electricity supply system planning and design and to apply these techniques to a study of the development of the Maltese electricity supply system.

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Public concern about energy-related environmental damage has put pressure on governments to enhance abatement policies. This has in turn led to increasing demands for information about and analysis of expected and optimal levels of environmental quality, and the means of influencing these levels. Energy demand modelling can act as a valuable tool in the production of this information, particularly where it relates to future levels of environmental quality and to how policy intervention can alter constraints facing consumers in order to achieve desired levels. The thesis focuses on two features of energy demand analysis. First, major developments in dynamic econometrics, and in particular the cointegration approach, have enabled energy demand modellers to incorporate long run equilibrating relationships between energy use and its main determinants, such as economic activity and relative prices, within a dynamic framework. Second, the existence of a diverse market for energy both in terms of the fuels used and the users suggests that energy demand should be analysed at a disaggregated level. The purpose of this thesis is to examine whether disaggregated dynamic energy demand modelling can provide additional valuable information for the formulation of environmental policy. The core of the thesis takes the form of six separate papers: three review papers link dynamic energy demand modelling with environmental policy and three case study papers use disaggregated dynamic energy demand modelling to examine aspects of future United Kingdom energy-related environmental quality and how it can be altered through changing the constraints facing consumers. While theory and traditional econometrics have provided useful information about energy consumption behaviour, the introduction of the cointegration approach and the error correction model are enabling economists to estimate more reliably the long run relationships between energy demand and its main determinants, and the gradual adjustment of consumers towards equilibrium consumption levels after a disequilibrating disturbance. This new information is giving a greater understanding of how to achieve desired future environmental quality levels. The heterogeneous nature of energy use, both in terms of the fuels used and their users, indicates that the accuracy of elasticity estimates and, thus, the quality of information they can provide for environmental policy might be improved through the disaggregation of dynamic energy demand modelling. Employing the cointegration approach and sectoral and fuel specific error correction models to generate estimates of income, three separate papers provide evidence in support of this argument. Individually, these papers provide information about sectoral and fuel specific elasticities, about how residential users alter their behaviour as economic constraints change and about how certain car users alter their fuel consumption patterns when provided with adverse environmental publicity about fuels. Together, these papers suggest that there exists considerable variation in income and real price elasticities between sectors and fuels, and that using the estimates generated by such disaggregated dynamic models will provide greater accuracy than aggregated and static models. These variations are of particular importance to environmental policy makers because of the difference in environmental impact associated with different fuels. The thesis, therefore, finds that, by generating more detailed and reliable elasticity estimates, disaggregated dynamic energy demand models provide new and valuable insights for the formulation of environmental policy. It concludes that disaggregated dynamic energy demand modelling will form an increasing share of the models used for environmental forecasts and policy analysis - although the overall interest in this area of research may shift as levels of certain energy-related environmental indicators improve (eg carbon dioxide, sulphur dioxide and nitrogen oxides) and others worsen (eg volatile organic compounds and PM10). The thesis suggests that considerable refinements in energy demand modelling can be made, both in the methods used and in the focus of empirical studies, which will lead to further improvements in the formulation of environmental policy.