Technology and energy management for cogeneration and trigeneration systems based on multi-objective optimization in integrated structures

Since the middle of the 19th century, the world's energy consumption has increased significantly due to the rapidly growing world population and improving quality of life after the industrial revolution. Global warming is one of the most critical problems for the world's future due to the high share of fossil fuels covering the ever-increasing energy demand and the carbon emissions released into the atmosphere. Although renewable energy sources seem to be an alternative to the solution of this problem, the estimates show that the dependence on fossil resources will continue to increase in the near future. The importance of energy efficiency in generation as well as in consumption is evident since 71% of the energy source of integrated structures, which have a significant share in Turkey's total energy consumption, is based on fossil fuels. Although the integrated structures differ according to their types, they are similar in terms of energy demand consisting of electricity, heating, domestic hot water, and cooling. Cogeneration and trigeneration systems are among the most effective alternatives to meet this demand. When the studies in the literature are examined, it is seen that one-dimensional solutions such as energy efficiency or energy saving are generally developed for a particular type of building. Unlike the examples in the literature, this thesis study aims to develop a valid model for all integrated structures by considering the energy requirement of integrated structures on a common denominator, and process analyses based on thermodynamic parameters have been examined on the basis of the first law of thermodynamics. In this context, it has been aimed to define the effective working intervals of the operational optimization of cogeneration and trigeneration systems depending on the genetic algorithm. Within this frame of reference, techno-economic analyzes of cogeneration and trigeneration options for the reference integrated structures have been made using the first law of thermodynamics analyses. In the study, the most effective operational processes have been defined as one generation using the multi-objective optimization method based on a genetic algorithm. In this process, measurable technical, economic, environmental, legislative, and social criteria and boundary conditions depending on the building type have been determined. The results of the multi-objective optimization showed that the problem does not have a single analytical solution; on the contrary, it contains a Pareto set of solutions depending on the objective function, constraints, and variability. According to the analysis results obtained from case studies consisting of a hospital, hotel, and shopping mall; 26-28% from primary energy sources, 25-34% savings in energy costs, and carbon dioxide emission savings of 450-500 tons/year, 230-280 tons/year, 72-78 tons/year, respectively, have been achieved. In addition, the Sustainable Heat Management Index, which was formed as a concrete contribution to the literature, has been developed to determine the priority of the heating or cooling system in the utilization of the heat released in the trigeneration system. This thesis consists of seven chapters. In the first chapter, there are analyzes on the conceptual information of the thesis, while a comprehensive literature research and publication review based on keywords are presented in the second chapter. Energy management and technology management for integrated structures, which form the main structure of the thesis, are discussed in the third and fourth chapters, respectively. The framework model developed in the study and the related methodological infrastructure are given in the fifth chapter. In the sixth chapter of the study, the techno-economic assessment and optimization results based on the framework model formed for the integrated structures taken as reference are explained in detail. In the conclusion part, specific findings obtained from the analyzes are given, and predictions and evaluations related to them are made. At the end of the study, suggestions regarding the issues to be addressed in the future are presented.