11801 - Thermodynamic System

Course Unit Page

SDGs

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Affordable and clean energy Industry, innovation and infrastructure Responsible consumption and production Climate Action

Academic Year 2021/2022

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 loro componenti, Pitagora.

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 IOL platform.

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

Assessment methods

The assessment methods consist of an oral part lasting about 45 minutes, during which the student must answer two questions, randomly extracted from a list of about eighty questions covering the entire program, list given at the last lesson of the course in the same dropbox folder that collects all the material presented during the lessons.

During the exam, with regard to Energetic Systems, their components and functions, is evaluated the student's ability to:

  • use the thermodynamic instruments correctly;
  • describe their operation;
  • theoretically justify their architecture;
  • represent their geometry with a free hand sketch;
  • evaluate their performance;

The evaluation, expressed in thirtieths, will be higher the more the student is:

  • autonomous in articulating responses to the two questions;
  • exhaustive in explaining the arguments;
  • precise in representing the functionality of the free-hand sketches.

The teaching of Energetic SystemsT (6 CFU) is one of the two modules that, together with the Machinery course (6 CFU), constitutes the integrated course of Energetic Systems and Machinery CI (12 CFU). The vote that will be recorded will be calculated with the arithmetic average of the single votes that the student will have obtained in the two modules. If the result of the average presents the decimal number 0.5, the vote will be rounded in excess. The "30 cum laude" is associated with the number 31. Consequently, in order to obtain the "30 cum laude" final evaluation, the student must be in one of the following two cases:

  • have received "30 cum laude" in both modules
  • obtaining "30 cum laude" in one form and 30 in the other.

The exam dates are comunicated in advance through the AlmaEsami web platform of the University of Bologna. It is possible to enroll to the exam from 7 to 2 days before the exam date. At the time of the exam the student must carry an identification document.

Teaching tools

The course will be carried out through the use of:

  • Slides and audiovisual supports

Office hours

See the website of Davide Moro