Papers by Mirko Stojiljkovic
Buildings use a significant amount of primary energy and largely contribute to greenhouse gases e... more Buildings use a significant amount of primary energy and largely contribute to greenhouse gases emission. Cost optimality and cost effectiveness, including cost-optimal operation, are important for the adoption of energy efficient and environmentally friendly technologies. The long-term assessment of buildings-related greenhouse gases emission might take into account cost-optimal operation of their energy systems. This is often not the case in the literature. Long-term operation optimization problems are often of large scale and computationally intensive and time consuming.
This paper formulates a bottom-up methodology relying on an efficient, but precise operation optimization approach, applicable to long-term problems and use with buildings simulations. We suggest moving-horizon short-term optimization to determine near-optimal operation modes and show that this approach, applied to flexible energy systems without seasonal storage, have satisfactory efficiency and accuracy compared with solving problem for an entire year. We also confirm it as a valuable pre-solve technique.
Approach applicability and the importance of energy systems optimization are illustrated with a case study considering buildings envelope improvements and cogeneration and heat storage implementation in an urban residential settlement. EnergyPlus is used for buildings simulations while mixed integer linear programming optimization problems are constructed and solved using the custom-built software and the branch-and-cut solver Gurobi Optimizer.
Energy, 2015, In Press, Corrected Proof
When complex energy systems are analyzed and when a large number of their components is observed,... more When complex energy systems are analyzed and when a large number of their components is observed, the destruction of exergy related to a single component is dependent on its own properties, but also on the characteristics of other components. The advanced exergy analysis is useful for providing supplementary information on the interaction between the components. It also exposes the real improvement potential related to each component of a system, but also of a system as a whole.
In this paper, an existing complex industrial plant with 33 components and 70 streams is analyzed using the first and second level of exergy destruction splitting for the boiler, as a main plant component from the aspect of destroying the useful work.
From the total unavoidable exergy destruction 97.28% comes from the internal irreversibility, 2.72% comes from the irreversibilities of other components, while 95.26% of the unavoidable exergy destruction (186.49 kW) comes from the internal irreversibility, and 4.74% from the external irreversibility.
The final result of the advanced exergy analysis for the steam generator is the total value of the avoidable exergy destruction as a real potential that can be avoided. It is 16.19% of the total exergy destruction of the component. That is less than the data obtained in the first decomposition level (186.49 kW) merely due to the existence of mexogenous exergy destruction.
Energy Conversion and Management 2015, 104, pp. 8–16
In this paper, a methodology for multi-objective optimization of trigeneration plants is presente... more In this paper, a methodology for multi-objective optimization of trigeneration plants is presented. It is primarily applicable to the systems for buildings’ energy supply characterized by high load variations on daily, weekly and annual bases, as well as the components applicable for flexible operation. The idea is that this approach should enable high accuracy and flexibility in mathematical modeling, while remaining efficient enough. The optimization problem is structurally decomposed into two new problems. The main problem of synthesis and design optimization is combinatorial and solved with different metaheuristic methods. For each examined combination of the synthesis and design variables, when calculating the values of the objective functions, the inner, mixed integer linear programming operation optimization problem is solved with the branch-and-cut method. The applicability of the exploited metaheuristic methods is demonstrated. This approach is compared with the alternative, superstructure-based approach. The potential for combining them is also examined. The methodology is applied for multi-objective optimization of a trigeneration plant that could be used for the energy supply of a real residential settlement in Niš, Serbia. Here, two objectives are considered: annual total costs and primary energy consumption. Results are obtained in the form of a Pareto chart using the epsilon-constraint method.
Exergy analysis and exergoeconomics are often used to evaluate industrial energy systems performa... more Exergy analysis and exergoeconomics are often used to evaluate industrial energy systems performance from the thermodynamic and economic points of view. While the classical exergy analysis can be used to recognize the sources of inefficiency and irreversibilities, so called advanced exergy analysis is convenient for identifying real potential for thermodynamic improvements of the system by splitting exergy destruction into avoidable and unavoidable parts.
In this paper, the advanced exergy analysis is used to identify performance critical components and the potential for exergy efficiency improvement of a complex industrial energy supply plant. This plant is a part of a rubber factory and its role is to provide steam, compressed air and cooling water to the production facilities, as well as hot water for space heating and sanitary use. The plant is first analyzed as is and the avoidable (and the unavoidable) part of exergy destruction is identified for each observed component. Then, the measures for removing the avoidable destruction are defined. Finally, the plant is analyzed as if the measures were implemented and avoidable losses eliminated. Numerical analysis is based on real data, some of which are collected during on site measurements. Large system of nonlinear and linear equations is defined and solved numerically using the Engineering Equation Solver.
Results of the presented analysis show the difference in thermodynamic and economic operational parameters of the plant for the cases without and with the efficiency measures implemented, i.e. the current state and the state with the avoidable irreversibilities eliminated. Beside obvious increase of exergy efficiency and enhancement of other thermodynamic parameters, certain improvement in the economy of the plant could be achieved.
Proceedings of the 16th Symposium on Thermal Science and Engineering of Serbia
On-site energy supply systems with cogeneration and trigeneration are acceptable, convenient and ... more On-site energy supply systems with cogeneration and trigeneration are acceptable, convenient and widely used solutions for increasing the efficiency of energy conversion, reducing pollution and securing energy supply. In order to make these systems financially more attractive, more efficient or more environmentally friendly, optimization of their structure, design parameters and operation is required. In this paper, an approach to synthesis, design and operation optimization applicable primarily to the systems for buildings energy supply is presented. Synthesis and design optimization is defined and solved as a combinatorial problem, using genetic algorithms and particle swarm optimization, while optimal operation regimes are determined using mixed integer linear programming, i.e. the branch-and-cut method. This approach is applied to optimize structure, design and operation related parameters of a trigeneration plant that could be used to supply a real residential settlement in Niš, Serbia. In this example, only a financial objective function, i.e. annual total costs, is taken into account, although the methodology might be used for other objective functions, as well as for multiobjective optimization.
Proceedings of the 16th Symposium on Thermal Science and Engineering of Serbia
Implementation of cogeneration and heat storage technologies in the district heating systems migh... more Implementation of cogeneration and heat storage technologies in the district heating systems might result with benefits related to efficiency, environmental impact, flexibility and security in heat supply. Impact on finances, and consequently the cost of heat depends on many factors. In this paper, potential for implementation of cogeneration together with heat storage in a typical small Serbian district heating system is analyzed from the heat cost and primary energy consumption viewpoints. Several models of cogeneration units are considered, in combination with various sizes of heat storage tanks. It is assumed that the plant operates during heating seasons only and always in an optimal regime. In order to determine the optimal operation regime, a mixed integer linear optimization problem is defined.
Proceedings of the 16th Symposium on Thermal Science and Engineering of Serbia
Thermal Science, Jan 1, 2010
Thermal Science, Jan 1, 2006
Doctoral Dissertation by Mirko Stojiljkovic
Books by Mirko Stojiljkovic
Uputstvo za izradu energetskih bilansa u opštinama, 2007
Teaching Documents by Mirko Stojiljkovic
Uputstva za laboratorijske vežbe iz Tehničkih materijala
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Papers by Mirko Stojiljkovic
This paper formulates a bottom-up methodology relying on an efficient, but precise operation optimization approach, applicable to long-term problems and use with buildings simulations. We suggest moving-horizon short-term optimization to determine near-optimal operation modes and show that this approach, applied to flexible energy systems without seasonal storage, have satisfactory efficiency and accuracy compared with solving problem for an entire year. We also confirm it as a valuable pre-solve technique.
Approach applicability and the importance of energy systems optimization are illustrated with a case study considering buildings envelope improvements and cogeneration and heat storage implementation in an urban residential settlement. EnergyPlus is used for buildings simulations while mixed integer linear programming optimization problems are constructed and solved using the custom-built software and the branch-and-cut solver Gurobi Optimizer.
Energy, 2015, In Press, Corrected Proof
In this paper, an existing complex industrial plant with 33 components and 70 streams is analyzed using the first and second level of exergy destruction splitting for the boiler, as a main plant component from the aspect of destroying the useful work.
From the total unavoidable exergy destruction 97.28% comes from the internal irreversibility, 2.72% comes from the irreversibilities of other components, while 95.26% of the unavoidable exergy destruction (186.49 kW) comes from the internal irreversibility, and 4.74% from the external irreversibility.
The final result of the advanced exergy analysis for the steam generator is the total value of the avoidable exergy destruction as a real potential that can be avoided. It is 16.19% of the total exergy destruction of the component. That is less than the data obtained in the first decomposition level (186.49 kW) merely due to the existence of mexogenous exergy destruction.
Energy Conversion and Management 2015, 104, pp. 8–16
In this paper, the advanced exergy analysis is used to identify performance critical components and the potential for exergy efficiency improvement of a complex industrial energy supply plant. This plant is a part of a rubber factory and its role is to provide steam, compressed air and cooling water to the production facilities, as well as hot water for space heating and sanitary use. The plant is first analyzed as is and the avoidable (and the unavoidable) part of exergy destruction is identified for each observed component. Then, the measures for removing the avoidable destruction are defined. Finally, the plant is analyzed as if the measures were implemented and avoidable losses eliminated. Numerical analysis is based on real data, some of which are collected during on site measurements. Large system of nonlinear and linear equations is defined and solved numerically using the Engineering Equation Solver.
Results of the presented analysis show the difference in thermodynamic and economic operational parameters of the plant for the cases without and with the efficiency measures implemented, i.e. the current state and the state with the avoidable irreversibilities eliminated. Beside obvious increase of exergy efficiency and enhancement of other thermodynamic parameters, certain improvement in the economy of the plant could be achieved.
Doctoral Dissertation by Mirko Stojiljkovic
Books by Mirko Stojiljkovic
Teaching Documents by Mirko Stojiljkovic
This paper formulates a bottom-up methodology relying on an efficient, but precise operation optimization approach, applicable to long-term problems and use with buildings simulations. We suggest moving-horizon short-term optimization to determine near-optimal operation modes and show that this approach, applied to flexible energy systems without seasonal storage, have satisfactory efficiency and accuracy compared with solving problem for an entire year. We also confirm it as a valuable pre-solve technique.
Approach applicability and the importance of energy systems optimization are illustrated with a case study considering buildings envelope improvements and cogeneration and heat storage implementation in an urban residential settlement. EnergyPlus is used for buildings simulations while mixed integer linear programming optimization problems are constructed and solved using the custom-built software and the branch-and-cut solver Gurobi Optimizer.
Energy, 2015, In Press, Corrected Proof
In this paper, an existing complex industrial plant with 33 components and 70 streams is analyzed using the first and second level of exergy destruction splitting for the boiler, as a main plant component from the aspect of destroying the useful work.
From the total unavoidable exergy destruction 97.28% comes from the internal irreversibility, 2.72% comes from the irreversibilities of other components, while 95.26% of the unavoidable exergy destruction (186.49 kW) comes from the internal irreversibility, and 4.74% from the external irreversibility.
The final result of the advanced exergy analysis for the steam generator is the total value of the avoidable exergy destruction as a real potential that can be avoided. It is 16.19% of the total exergy destruction of the component. That is less than the data obtained in the first decomposition level (186.49 kW) merely due to the existence of mexogenous exergy destruction.
Energy Conversion and Management 2015, 104, pp. 8–16
In this paper, the advanced exergy analysis is used to identify performance critical components and the potential for exergy efficiency improvement of a complex industrial energy supply plant. This plant is a part of a rubber factory and its role is to provide steam, compressed air and cooling water to the production facilities, as well as hot water for space heating and sanitary use. The plant is first analyzed as is and the avoidable (and the unavoidable) part of exergy destruction is identified for each observed component. Then, the measures for removing the avoidable destruction are defined. Finally, the plant is analyzed as if the measures were implemented and avoidable losses eliminated. Numerical analysis is based on real data, some of which are collected during on site measurements. Large system of nonlinear and linear equations is defined and solved numerically using the Engineering Equation Solver.
Results of the presented analysis show the difference in thermodynamic and economic operational parameters of the plant for the cases without and with the efficiency measures implemented, i.e. the current state and the state with the avoidable irreversibilities eliminated. Beside obvious increase of exergy efficiency and enhancement of other thermodynamic parameters, certain improvement in the economy of the plant could be achieved.