Learning objectives
The course provides the basic knowledge on the theory of Energy Conversion Plants, with reference both to their components and to whole plants for power generation. In particular the study will focus on most common actual Power Plants used for energy generation: steam plants, gas turbines, reciprocating internal combustion engines.
Knowledge and understanding:
At the end of the course the student will know the main characteristics of systems for energy generation and the most common power plants used today. He/she will also acquire the knowledge concerning the evaluation of thermodynamic processes, their representation on thermodynamic diagrams, the calculation of the thermodynamic parameters and the amount of heat and work exchanged, both with reference to the ideal and real cases. He/she will then need to know problems, limitations, advantages and disadvantages power plants/engines and their main components.
Applying knowledge and understanding:
The student will be able to calculate performance parameters of engines and power plants with particular reference to efficiency and specific fuel consumption. He/she will also be able to define the performance of the ideal and real thermodynamic processes that occur in Energy Conversion Systems in order to assess in a qualitative and quantitative way thermodynamic states in different locations of the plant as well as the methods to improve conversion efficiency.
Making judgments:
The student will have tools and knowledge needed to critically evaluate and compare different solutions for the realization of specific energy conversion processes and power generation in Engines and Power Plants starting from main performance parameters usually used to this purpose and taking into account any possible alternatives.
Communication skills:
The student must have the necessary tools to effectively present evaluations and comparisons of different solutions for the realization of specific energy conversion processes and power generation in Engines and Power Plants through both graphs and numerical calculations and representation of thermodynamic cycles giving a clear idea of the key performance parameters usually used to this purpose.
Learning skills:
The student will be able, starting from the basic knowledge acquired in the course, to get by himself information and technical data on different Energy Conversion Systems that can be studied and/or proposed on the market, thus continuously updating their skills on the solutions proposed and/or applied in the field of conversion processes and energy generation.
Prerequisites
A basic knowledge of fundamentals of Mathematics, Physics, Thermodynamics and Fluid Mechanics is required.
Course unit content
Energy consumption in Italy and in the world: traditional and renewable energy sources. Energy systems and fluid machinery: characteristics and classification. Internal and external combustion Power Plants. Recall of thermodynamic fundamentals. Applications of the conservation equations: continuity, energy and momentum. Basics on the utilization of hydraulic power plants. Energy from fossil fuels: combustion processes and fuel properties. Mass balance, composition of products, air/fuel ratio. Thermodynamic cycles: representation on thermodynamic diagrams, thermodynamic processes, calculation of work and heat exchanges. Ideal, limit and real cycles. Efficiencies in Power Plants and specific fuel consumption. Cost of energy, utilization coefficient.
Compression and expansion transformations on thermodynamic diagrams, work and efficiency in compressions and expansions.
Steam plants: basic circuit, saturated steam and superheated steam cycles. Steam generators: layouts, efficiency, superheaters, economizers and air preheaters. The condenser and cooling towers. Regeneration and reheat. Thermodynamic cycles on (h,s) and (T,s) diagrams. Performance evaluation for steam plants and optimization.
Reciprocating internal combustion engines (ICE). Operating principles and basic components. Ideal thermodynamic cycles. Calculation of power output in internal combustion engines. Brake Mean Effective Pressure (bmep). Volumetric efficiency. Hints on combustion processes, air intake and fuel injection. Fundamentals on supercharging and turbocharging.
Gas turbines, reference thermodynamic cycles, efficiency and specific work. Air-fuel ratio, combustion chambers. Thermodynamic cycles on (h, s) and (T,s) diagrams. Performance evaluation for simple and regenerated gas cycles and optimization. The turbine inlet temperature (TIT).
Parameters for the performance characterization of fluid machines: hints on dimensional analysis, dimensionless groups, characteristic curves.
Full programme
Energy consumption in Italy and in the world: traditional and renewable energy sources. Energy Systems and fluid machinery: characteristics and classification. Internal and external combustion Power Plants. Elements of thermodynamics: 1st and 2nd principle, gases and vapors, thermodynamic diagrams and their use. The Mollier diagram. Applications of the fundamental equations: continuity, energy and momentum. Basics of the utilization of hydraulic power plants. Energy from fossil fuels: combustion processes and fuel properties. Mass balance, composition of products, air/fuel ratio. Thermodynamic cycles: representation on thermodynamic diagrams, thermodynamic processes, calculation of work and heat exchanges. Ideal, limit and real cycles. Efficiencies in power plants and specific fuel consumption. Cost of energy, utilization coefficient.
Compression and expansion transformations on thermodynamic diagrams, work and efficiency in compressions and expansions.
Steam plants: basic circuit, cycles in saturated steam and superheated steam. Steam generators: types and layouts. Efficiency of the steam generator. Superheaters and economizers. Air preheaters. The condenser and cooling towers. Regeneration and reheat. Thermodynamic cycles on (h,s) and (T,s) diagrams. Performance evaluation for steam plants with simple cycle, with reheat and regeneration. Optimization of steam cycles with reference to specific work and efficiency.
Reciprocating internal combustion engines (ICE). Operating principles and basic components. Ideal thermodynamic cycles. Calculation of power output in internal combustion engines. Brake Mean Effective Pressure (bmep). Volumetric efficiency. Combustion processes in spark-ignition and Diesel engines. Air intake and fuel injection in ICE: intake and exhaust systems, valves and actuation systems, ideal and real valve timing and related polar diagram. Fundamental on supercharging and turbocharging.
Gas turbines, reference thermodynamic cycles, efficiency and specific work. Air-fuel ratio, combustion chambers. Thermodynamic cycles on (h, s) and (T,s) diagrams. Performance evaluation for simple and regenerated gas cycles. Optimization of gas cycles with reference to specific work and efficiency. The turbine inlet temperature (TIT): effects on efficiency and problems arising from materials strenght. Basics on blade cooling.
Bibliography
The topics addressed in the course are presented with a similar approach and with identical symbols in the following texts:
C.Caputo, "Gli impianti convertitori di energia", Masson, 1997.
C.Caputo, "Le Macchine Volumetriche", Masson, 1999.
C.Carcasci, B.Facchini, "Esercitazioni di Sistemi Energetici", ed.Esculapio, 2016.
G.Negri di Montenegro, M.Bianchi, A.Peretto, "Sistemi Energetici e Macchine a Fluido", ed.Pitagora, 2009.
Suggestions for further readings:
O.Acton, C.Caputo, Macchine a fluido, vol.1, 'Introduzione allo studio delle Macchine', UTET, 1979.
O.Acton, C.Caputo, Macchine a fluido, vol.2, 'Impianti Motori', UTET, 1992. O.Acton, Macchine a Fluido, vol.3, "Turbomacchine", UTET, 1990. G.Ferrari, "Motori a Combustione Interna", Il Capitello, 2016.
Teaching methods
Teaching will be developed in the form of lectures in presence (or online if the health situation relating to COVID requires it) during which the topics of the course will be addressed from both a theoretical point of view (in order to facilitate understanding of the topics presented with proper links to the student knowledge background) and a practical approach (through the presentation of quantitative examples of specific power plants and the calculation procedures that lead to the numerical evaluation of the performance parameters and thermodynamic cycles.
In particular, the theoretical lessons will give fundamental tools for the study of thermodynamic transformations and thermodynamic cycles in Energy Systems and for the calculation of operational and performance parameters. The practical applications presented will be aimed to give the student the required familiarity with the units of measurement, with the quantitative calculation of ideal and real thermodynamic cycles, as well as with the evaluation of the performance of power plants and engines studied in the course.
Assessment methods and criteria
Verification of learning is achieved through the final exam only, which ascertains the acquisition of knowledge and skills (i.e. the acquisition of learning results) through a written test and oral interview.
The written test consists of a numerical exercise and structured questions. The exercise is based on a calculation problem similar to those solved during lectures, requiring the numerical calculation of a thermodynamic cycle applied to a power plant and the quantitative evaluation of its performance and operating parameters. The numerical exercise requires that results provided to the specific questions are correct within reasonable limits. The structured questions regard fundamental aspects of the theory and are given as closed-ended questions. During the written test the use of notes or books of any kind is not allowed.
To be admitted to the oral exam, it is required to correctly answer the exercise questions indicated as threshold, and a specific number of structured questions. The other questions and other questions will allow to increase the partial vote.
Students who pass the first test will be admitted to an oral test, consisting in: (1) a review of the written test in which the examiners inform the student about the correction criteria, receive any clarifications from the student and decide whether to change the judgment; (2) two theoretical questions on the topics covered in the course and on the application of the theory to original problems: in particular the critical ability, the language skills and the ability to correlate topics will be evaluated. Each of the two questions is assessed on a scale from 0 to 30. To pass the exam, the evaluation must be sufficient for each of the two questions (i.e. if the answer to even one of the two questions is judged not sufficient, the exam is failed). The final grade is obtained by calculating the arithmetic average of the marks in the written test and the two questions in the oral test.
Please note that online registration for the exam is MANDATORY to take the exam.
The aforementioned tests will be in presence if the health situation allows, the tests will be online.
Other information
Attendance to the course lectures and to the presentation of numerical examples is highly recommended.
2030 agenda goals for sustainable development
Affordable and clean Energy
