In this work it is presented an equilibrium model, capable to predict the composition of the generated gas, its Lower Heating Value (LHV), the gasification efficiency, the ratio air/biomass and the  ratio gas/biomass in a downdraft gasifier. The model describes the influence of  the moisture content of the biomass and the gasification temperatures on the composition and properties of the produced gases, like the low heating value (LHV). It is assumed that all the chemical reactions taking place  in the gasification area are in thermodynamic equilibrium. The model doesn't considered tar formation. It is not considered formation of other hydrocarbons (CxHy) than methane. The types of biomass used for modelling are: sugarcane bagasse, paddy husk, pine sawdust, mixed paper waste and municipal solid waste. The effect of gasification temperature and moisture content of biomass over the gas composition has been also investigated. Also an exergo-economic analysis of cogeneration system forming by a downdraft gasifier associated to an internal combustion engine was carried out, using sugar cane bagasse, rice husk, and pine sawdust, as fuel in gasification processes. At 700°C the highest amount of CO and CH4 are produce. The amount of CH4 and CO decrease with the temperature when the gasification temperature is increased from 700°C to 1000°C. The amount produced H2 does change so much between the gasification at 700°C and 1000°C. But the amount produced hydrogen is somewhat higher at 800°C. The lower heating value (LHV) of the synthesis gas from gasification of sugarcane bagasse the LHV of the produced gas is 4,09MJ/Nm3; for gasification of pine the LHV of the produced gas is 5,32MJ/Nm3; for gasification of rice husk the LHV of the produced gas is 3,14MJ/Nm3, for gasification of mixed paper waste the LHV of the produced gas is 4,51%, and for gasification of municipal solid  waste the LHV of the produced gas is 3,95MJ/Nm3. The cold and hot efficiency of gasification process at 800°C for bagasse with 20% moisture content are  55,32% and 84,90% respectively.

Магистерская диссертация состоит из введения, трех глав, заключения, списка литературы и 2 приложения. В работе рассмотрены теоретические основы, отечественный опыт строительства мини-ТЭЦ. Проанализирован район расположения планируемого научно-образовательного центра, рассмотрены реализованные проекты мини-ТЭЦ и проанализированы существующие аналогичные технологии. Определены источники финансирования, сформирован бюджет проекта, рассчитаны показатели экономической эффективности проекта. В заключении сформулированы основные выводы и обобщены результаты исследования. / The master's thesis consists of an introduction, three chapters, conclusion, list of references and 2 appendices. The paper discusses the theoretical foundations, domestic experience in the construction of mini-CHP. The location area of the planned scientific and educational center is analyzed, implemented projects of mini-CHPs are reviewed, and existing similar technologies are analyzed. Sources of financing have been identified, a project budget has been formed, and indicators of the project's economic efficiency have been calculated. In conclusion, the main conclusions are formulated and the results of the study are summarized.

This thesis discusses the thermoeconomic modeling and simulation of micro-CHP systems powered by various prime movers. Micro Cooling, Heating, and Power (micro-CHP) is becoming an increasingly important energy option as the demand for electrical power as well as heating and cooling for buildings increases worldwide. Micro-CHP has the potential to increase the total energy efficiency for cooling, heating, and powering residences, offices, and other relatively small buildings by using waste thermal energy from electricity production to deliver heating and cooling. Calculation methodologies are presented for the different components of micro CHP systems using thermodynamic cycles and mass and energy balances. System performance characteristics are calculated and compared for different prime movers using various fuels. Performance characteristics that are compared include fuel consumption, monthly energy savings, and system energy efficiencies.

The aim of this diploma thesis is assessment of options to reduce energy consumption in industrial areal belonging to Fritzmeier company. This thesis is divided into three parts. In the first part there is analysis of electrical energy and natural gas consumption in considered industrial area based on data from energy audit. The second part consists of short theoretical elaboration of cogeneration and cogeneration technologies, design of five variants of use of cogeneration units with combustion engine running on natural gas and evaluation of proposed variants. Third part of this thesis is about modernization of lighting system in small section of assembly hall. In this part parameters of new LED lighting system for selection are set, based on theoretical elaboration of LED problematics and five variants offered by specialized companies are evaluated.

This Master´s thesis deals with a theoretical micro cogeneration unit design contains hot air microturbine using energy from biomass. In the first part of the thesis there are model examples of energy consumption in typical family or apartment houses. In the next part there is the overview of micro cogeneration commercial units which can be used in model examples of a family or apartment housing. According to the assignment of this thesis and based on the analysis of model examples a new cogeneration system is designed. The last part of the thesis deals with the economic evaluation of the new cogeneration system compared with commercial systems.

The technology of cogeneration is reviewed through an examination of the prime movers most commonly used for this purpose in industrial and commercial facilities. The systems characteristics which are of particular importance to the congeneration application are emphasized along with the advantages and limitations of each. A comparative examination of the methods selected for use in the evaluation of profitability in cogeneration systems is presented. The examination focuses on the interpretation of the projections made by each method and their implications for the decision to adopt cogeneration. A computer simulation model is utilized to perform a sensitivity study in order to identify the key variables determining economic viability of cogeneration. Employing a gas turbine system as a representative installation, the variables used in the sensitivity study are presented along with the justification for the assignment of the baseline and study range values. A simplified method for analyzing the profitability of cogeneration systems is developed. The technique is specifically tailored to gas turbine based cogeneration which is the technology most commonly proposed for moderate size facilities. The significance of the incremental energy consumption factor as a determinant of profitability is investigated. The application of the simplified method for comparative studies of different gas turbine systems is described and the results compared to projections made by the simulation model. Finally, the simplified method is utilized to examine the implications of regional fuel price differences and the implications of natural gas price deregulation on the profitability of gas turbine cogeneration.

The topic of the thesis is economical appraising of run the power from cogeneration units to different voltage level. There is sloves in the text, how and under what conditions we can find an optimal solution for the deployment of cogeneration units to the electricity network. The main criterion is the loss of networks and their economic evaluation. We are a description of the different types of cogeneration units, the economic balance and a treatise on losses in electrical networks.

Master of Science / Department of Architectural Engineering and Construction Science / Fred Hasler / Data center space and power densities are increasing as today’s society becomes more dependent on computer systems for processing and storing data. Most existing data centers were designed with a power density between 40 and 70 watts per square foot (W/SF), while new facilities require up to 200W/SF. Because increased power loads, and consequently cooling loads, are unable to be met in existing facilities, new data centers need to be built. Building new data centers gives owners the opportunity to explore more energy efficient options in order to reduce costs. Fuel cells are such an option, opposed to the typical electric grid connection with UPS and generator for backup power. Fuel cells are able to supply primary power with backup power provided by generators and/or the electric grid. Secondary power could also be supplied to servers from rack mounted fuel cells. Another application that can benefit from fuel cells is the HVAC system. Steam or high-temperature water generated from the fuel cell can serve absorption chillers for a combined heat and power (CHP) system. Using the waste heat for a CHP system, the efficiency of a fuel cell system can reach up to 90%. Supplying power alone, a fuel cell is between 35 and 60% efficient. Data centers are an ideal candidate for a CHP application since they have constant power and cooling loads. Fuel cells are a relatively new technology to be applied to commercial buildings. They offer a number of advantages, such as low emissions, quiet operation, and high reliability. The drawbacks of a fuel cell system include high initial cost, limited lifetime of the fuel cell stacks, and a relatively unknown failure mode. Advances in engineering and materials used, as well as higher production levels, need to occur for prices to decrease. However, there are several incentive programs that can decrease the initial investment. With a prediction that nearly 75% of all 10 year old data centers will need to be replaced, it is recommended that electrical and HVAC designer engineers become knowledgeable about fuel cells and how they can be applied to these high demand facilities.

South Africa is on a path of dramatically increasing its energy supplying capabilties. Eskom (the main utility supplying electricity to the national grid) recently announced that future power station technologies will focus on renewable energy and nuclear power. This is done in an effort to reduce South Africa’s dependance on burning fossil-fuels and thereby decreasing CO2 emissions and other harmful gases. This, together with the fact that there are a lot of fresh water scarce areas especially along the Eastern Cape coast of South Africa, is what inspired this study. This study investigates the use of a 200 MWth High Temperature Reactor (HTR) for cogeneration purposes. Heat from the reactor is utilised for electricity generation (Rankine cycle) and process heat (desalination). Two desalination concepts were evaluated thermodynamically and economically, namely Multi-Effect Distillation (MED) and Reverse Osmosis (RO). Computer software, Engineering Equation Solver (EES), was used to simulate different cycle configurations, where the heat available in the condenser was increased successively. The coupling of the two desalination technologies with a HTR was compared and it was found that a RO plant produces nearly twice as much water while sending the same amount of electricity to the grid (compared to coupling with MED). Coupling options were investigated and each simulation model was optimised to deliver maximum output (power and water). The best configuration was found to be the coupling of a HTR with a RO plant producing 86.56 MW generator power. This is equal to 2077 MWh/day. Using 332 MWh/day for desalination through RO, delivers 73 833 m3/day fresh water and results in 1745 MWh/day sent to the grid. This scenario is the best option from a thermodynamic and economic point of view. From an investment point of view, it will produce an Internal Rate of Return (IRR) of 10.9 percent and the Net Present Value (NPV) is calculated to be R 2,486,958,689. The results and analysis for the different cycle configurations are presented in such a way that an easy comparison can be made. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011

Les travaux de cette thèse visent à étudier un système de micro-cogénération de structure innovante motorisé par un moteur Stirling à piston libre « double effet ». Ce système est caractérisé par un fort couplage entre la partie thermo-mécanique et la partie mécano-électrique, assurée par une génératrice à induction linéaire tubulaire à mover massif. En effet, le piston de compression joue également le rôle du mover de la machine électrique. Le modèle thermo-mécanique non-linéaire du moteur Stirling « double effet » a été tout d’abord rappelé ce qui a permis de dégager le mode de couplage optimal entre le moteur thermique et la génératrice électrique. Ensuite, l’étude de la partie génératrice électrique a porté sur la validation numérique et expérimentale du modèle électromagnétique par la résolution des équations de Maxwell en magnétodynamique, sur l’identification des paramètres de la machine linéaire en combinant les méthodes théoriques avec les essais expérimentaux et finalement sur la réalisation expérimentale de la commande vectorielle à flux orienté afin de maîtriser la force résistante en régime oscillatoire. Puis, la chaîne des convertisseurs d’électronique de puissance qui assure la connexion du système électrogène au réseau domestique a été étudiée en vue d’adapter la production électrique aux contraintes du réseau. Ensuite, un « banc d’essai virtuel » du système global a été réalisé à l’aide de Matlab/ Simulink, mettant en place le modèle thermo-mécanique non-linéaire du moteur Stirling « double effet », le modèle dynamique de la génératrice à induction linéaire tubulaire, le modèle des convertisseurs statiques ainsi que les commandes associées : commande P.I.D en position, commande vectorielle à flux orienté, et commande PFC. Le « banc d’essai virtuel » a permis de valider le couplage des modèles, les performances des commandes ainsi que le fonctionnement stabilisé du système en mode oscillatoire. Puis, sous l’hypothèse d’un contrôle/ commande du système parfait, un modèle global aux « valeurs moyennes instantanées », appelé « plateforme énergétique », a été établi. Ce modèle est d’exécution rapide, compatible avec un outil d’optimisation « multi-variables », « multi-objectifs ». Enfin, l’étude de dimensionnement optimale de la chaîne électromécanique complète du système basé sur l’algorithme génétique NSGA-II a permis d’obtenir plusieurs solutions significative afin de maximiser la puissance électrique injectée au réseau et de minimiser le coût total de la chaîne. Le temps de rentabilité optimal du système est également considéré à la fin de cette thèse. / The work of this thesis aims to study a system of micro-cogeneration innovative structure powered by a free piston Stirling engine "double effect." This system is characterized by a strong coupling between the thermo-mechanical parts and the mechanico-electrical part, provided by a linear induction generator tubular solid mover. In fact, the compression piston also acts as the mover of the electrical machine. The non-linear thermo-mechanical model of the Stirling engine "double effect" allowed to identify the optimal mode of coupling between the engine and the electric generator. Then, the study of the electric generating portion focused on numerical and experimental validation of the electromagnetic model by solving Maxwell's equations in magneto, the identification of parameters of the linear machine combining theoretical methods with experimental tests and finally on the experimental embodiment of the vector field oriented control to control said load system in oscillatory. Then the chain of electronic power converters that connects the generator to the home network system has been studied in order to adapt to the constraints of power generation network. Then, a "virtual test bed" of the overall system was made using Matlab / Simulink so as to implement the non-linear thermo-mechanical model of the Stirling engine "double effect", the dynamic model of the generator tubular linear induction, the model of static converters and related commands : PID position control, vector oriented in flow control and PFC control. The "virtual test bed" was used to validate the coupling models, the performance of controls and the stable operation of the system in oscillatory mode. Then, under the assumption of a command / control of the perfect system, a comprehensive model for the "average instantaneous values" called "energy hub" was established. This model is fast execution, consistent with a "multi-objective" optimization tool "multivariate". Finally, the study of optimal design of the complete electromechanical chain system based on genetic algorithm NSGA-II gave several significant solutions to maximize the electric power fed into the grid and to minimize the total cost of the chain . Time optimal efficiency of the system was also considered at the end of this thesis.