11801 - Thermodynamic System

Learning outcomes

The course aim is to give to the students the basic knowledge to carry out the thermodynamic analysis of the principal basic and complex energetic systems and of their components.
In the course are briefly recalled the basic thermodynamic fundamentals and in particular the fluid motion equation in both thermic and mechanical form, the Carnot cycle, the thermodynamic diagram for air and water steam and the design of heat exchangers.

Course contents

Steam power plant

The main components of the steam power plant, the thermodynamic of the cycle and the quantification of the energetic flows are presented. Effect of the condenser pressure, of the boiler pressure and of the superheat temperature on the thermodynamic efficiency of the steam cycle. Effect of regeneration and reheat on the steam cycle. Exergetic analysis of the Hirn cycle. Deaerator architecture and behaviour. Basic consideration on fuel characteristics, higher and lower heating values, stoichiometric air mass, air excess, nocive emissions and their control. Boiler architecture: heat exchange diagram for the radiation boiler, evaluation of the combustion temperature, efficiency, thermic load and limitation of its potentiality. Limitation on the stack temperature: the acid dew phenomena. Limitation on the maximum temperature value allowed in a steam power plant. The steam condenser, its energetic balance and design. An outline on the energetic transformation in the steam turbine and definitions of its internal efficiency. Definition of the whole efficiency of the steam power plant simply super-heat and its dependence from the thermodynamic efficiency of the Hirn cycle and the efficiency of the single components. Lay-out of a reheat steam power plant with three regeneration levels, its (T,s) thermodynamic diagram, determination of the steam flow rate in all the ducts between the plant components in function of the mechanical power required to the shaft of the steam turbine and definition of the thermodynamic efficiency of the whole plant.

Turbogas power plant

Lay-out of the basic plant and its thermodynamic (T,s) diagram, Bryton cycle definition. Internal efficiency of the compressor and of the turbine. Effect of the temperature level after the combustion phase and of the compression ratio on the specific energy required, on the specific work and on the thermodynamic efficiency of a Brayton cycle. Exergetic analysis of the Brayton cycle. The combustion chamber architecture, its energetic analysis and efficiency. The problem of the maximum temperature value allowed in a turbogas power plant. Thermodynamic efficiency and whole turbogas plant efficency. An outline on the turbogas plant regulation: single and two-shaft plant architecture. Heat recovery from exhaust gas in the turbogas plant. Turbogas plants with refrigerated compression and reheated expansion.

Turbogas and steam plant comparison

The thermodynamic efficiency values and the maximum temperature level allowed in the two plants, the difference in the introduction of the heat in the two plants and its effect on the efficiency of the component.

Refrigeration and heat pump plant

Plant lay-out and thermodynamic diagram (T,s) and (p,h) for the cycle with one and two pressure levels. Coefficient of performance (COP) for refrigeration and heat pump cycles. Refrigerant properties and their environmental impacts.

Readings/Bibliography

G. Negri di Montenegro,M. Bianchi, A. Peretto, Sistemi energetici e macchine a fluido (Vol. 1), Pitagora.

G. Morandi, Macchine ed apparecchiature a vapore e frigorifere, Pitagora.

G. Minelli, Turbine a gas, Pitagora

G. Lozza, Turbine a gas e cicli combinati, Esculapio

Teaching methods

The lessons are frontal in the classroom. The teacher, replacing the traditional blackboard, uses a tablet connected to the projector to develop the concepts and to show the supporting teaching material. At the end of the lesson the teacher makes available the material shown in a pdf file, downloadable from Virtuale platform.

Attendance is strongly recommended for better learning of concepts and notions, but does not affect the final evaluation process.

Assessment methods

The assessment of learning consists of an oral examination lasting approximately 45 minutes, during which the student is required to answer two questions: one concerning the part of the course devoted to the thermodynamics of energy systems, with particular reference to steam power plants, gas turbine plants, and refrigeration cycles, and one concerning the operation of their main components.

The questions are selected at random from a list of approximately eighty questions covering the entire course syllabus. The list is made available on the VIRTUALE platform during the final lecture of the course. On the same platform, students can also access the PDF files of all lectures and the corresponding video recordings.

The oral discussion of the two questions is intended to assess the achievement of the expected learning outcomes, with particular reference to the Dublin Descriptors.

In particular, the following will be assessed:

• knowledge and understanding of the thermodynamic principles underlying the operation of steam power plants, gas turbine plants, and refrigeration cycles, as well as the constructional and functional characteristics of their main components and the parameters affecting their performance (Dublin Descriptor 1 – Knowledge and understanding);

• the ability to apply the acquired knowledge to the thermodynamic analysis of energy systems, the determination of the main energy and performance parameters, and the interpretation of plant layouts, thermodynamic diagrams, and the operating conditions of the various components (Dublin Descriptor 2 – Applying knowledge and understanding);

• the ability to make independent assessments by comparing different plant configurations and technological solutions and justifying conclusions on the basis of performance, energy efficiency, operating conditions, and component characteristics (Dublin Descriptor 3 – Making judgements);

• clarity of presentation, command of technical terminology, and the ability to describe and critically discuss the operation of the plants and their main components, including through the use of freehand sketches and diagrams (Dublin Descriptor 4 – Communication skills).

The final grade is expressed on a scale of 30 and takes into account the following criteria:

• knowledge and understanding of the course topics: 25%;

• ability to apply knowledge and integrate the different topics: 25%;

• critical analysis skills and independent judgement: 20%;

• command of technical terminology and clarity of presentation: 15%;

• ability to explore topics in depth and engage in critical discussion: 15%.

The grade will be higher when the student demonstrates:

• independence in developing and presenting the answers to the two questions;

• completeness and thoroughness in the presentation;

• accuracy in drawing and functionally explaining freehand plant layouts and thermodynamic diagrams.

The examination is passed with a minimum grade of 18/30. Honours may be awarded in the case of an outstanding performance.

The 6-ECTS course unit Sistemi Energetici T, together with the 6-ECTS course unit Macchine T, constitutes the 12-ECTS integrated course Sistemi Energetici e Macchine T C.I.

The final grade recorded for the integrated course is calculated as the arithmetic mean of the grades obtained in the two course units. If the resulting average has a decimal part of 0.5, the grade is rounded up to the next whole number.

For the purpose of calculating the average, a grade of 30/30 with honours is assigned the numerical value of 31. Consequently, a final grade of 30/30 with honours may be awarded in either of the following cases:

• 30/30 with honours obtained in both course units;

• 30/30 with honours obtained in one course unit and 30/30 in the other.

Nine examination dates are scheduled for 2027, on the dates published on the University of Bologna’s AlmaEsami platform.

Students may register for an examination from seven to two days before the examination date. On the day of the examination, students must present a valid identity document. 

For each examination session, students who have been granted working-student or student-athlete status may request an alternative examination date in place of one of the regular examination dates scheduled within the same session.

The request must be submitted to the lecturer at least 14 days before the first examination date of the session, so that a date compatible with all requests received can be identified.

In accordance with the University Code of Ethics, students are required to act with the utmost integrity during the examination.

Any conduct aimed at improperly altering the outcome of the examination is prohibited, including copying, plagiarism, unauthorised access to materials or online learning resources, and the use of unauthorised artificial intelligence tools or systens.

The possession or use of unauthorised devices or materials during the examination will result in the immediate termination and invalidation of the examination, as well as a report being submitted to the relevant University offices.

Conduct in breach of these provisions may result in disciplinary proceedings and, where it may constitute a criminal offence, in a report to the competent authorities, with the possible initiation of criminal proceedings.

Teaching tools

The course will be carried out through the use of:

• Slides and audiovisual supports

Office hours

See the website of Davide Moro