69726 - ENERGY USE AND CONVERSION T

Course Unit Page

Academic Year 2018/2019

Learning outcomes

This course aims to provide a basic knowledge of conventional and non-conventional energy conversion systems based on fluid machines. Energy conversion systems are described starting from thermodynamic point of view up to schematic lay-outs with basic energy balances. Moreover the most important components are analysed giving the fundamentals information about their way of operation. Some calculations are presented in order to obtain a preliminary design of the most important fluid machines described in the course.

Course contents

1. World energy demand, primary and secondary sources. Renewable and not-renewable energy sources. Emissions and CO2 mass balance.

2. Photovoltaic energy conversion.

3. Wind energy. Mechanical Power extracted from the wind. Betz's factor. Power coefficient

4. Fuels and Combustion. Heating Value. Calorimeters (Junkers and Mahler). Stoichiometric air demand and excess air. Ostwald diagram for combustion products.

5. Recalls of applied thermodynamics. Energy balance for a closed and an open system.

6. Steam power plants. Plant configurations,. Carnot, Rankine, and Hirn cycle. Methods for steam power plant efficiency improvement

7. Regenerative steam power plants. Choice of the optimum extraction pressure. Steam pre-haters.

8. Evolution of steam boiler design.

9 . Combustion chamber balance and mean temperature of the gases. Heat recovery from combustion gases. Water and air pre-heating.

10. Steam generator efficiency. Definition and its indirect evaluation. Effect of excess air and power rate on the efficiency. Volumetric thermal load.

11. Gas turbine power plants. Introduction, Brayton cycle analysis and optimization. (blade cooling)

12. Cogeneration: Steam turbine cogenerative back pressure and extraction-condensation power plants, ICI and TG cogenerative power plants.

13. Combined cycle power plants. Heat recovery boilers.

14. Inverse Carnot cycle, cooling power plants, refrigerants, properties and impact. One and two pressure level refrigerating cycle. Heat pump and Adsorbtion cooling cycle.

15. Reciprocating and rotary positive displacement pumps and compressors. Survey on the main types of positive displacement pumps. Definitions and test.

16. Turbomachines. Basics. Axial, radial, impulse and reaction machines. The Eulerian theory.

17. Nozzles: Hugoniot equation. Velocity triangles. De Laval and Curtis impulse turbines.

18.§ Analysis of the stage of a reaction turbine. Mixed an multi-body turbine. Axial thrust compensation. Basic regulation principles: throttling and partialization.

19. Hydraulic centrifugal Pumps. Basics. Total head for pumps. Power and efficiency. Centrifugal pumps and: total head, characteristic curves and regulation.

20. Basic principles of similitude theory, specific speed and transposition laws. Parallel and serial pumps operation. Description and modality of operation of a pump test rig.

21. Installation problems. Cavitation, NPSH.

22. Hydraulic Power Plants: Pelton turbine, Francis turbine, Testing and representation of hydraulic turbines performances by hill diagrams. (§ Helical and Kaplan turbines).

23. Architecture of I.C.E. Indicator and distribution diagrams.

24. Thermodynamic analysis of internal combustion engines I.C.E.. Beau de Rochas, (Otto), Diesel and Sabathè cycles.

25. Power and efficiency of a I.C.E., Mean cylinder pressure, mean velocity, aspect ratio. Preliminary design.

26. § Brief account on two stroke engine scavenging.

27. Torque, power, and specific consumption curves at full and reduced load. Pollutants.

§ not requested for 69726 - CONVERSIONE E UTILIZZAZIONE DELL'ENERGIA T Laurea in Ingegneria per l'ambiente e il territorio (9198)

 

Module 2: Principi di ingengeria elettrica, only for 69726 - CONVERSIONE E UTILIZZAZIONE DELL'ENERGIA T Laurea in Ingegneria per l'ambiente e il territorio (9198)

General theory

From field theory to circuit theory, Kirchhoff's laws, electric power, ideal voltage and current source, resistor, inductor, capacitor. Alternate current regime.

Electrical energy production

Synchronous machine. Main characteristics and operating principle as generator and compensator. Photovoltaic generator.

Electrical Energy transportation and distribution

Three-phase systems. Three-phase systems with neutral wire. Reactive power compensation. Transformer: main characteristics and operating principle. Equivalent electrical network. Three phase transformers.

Electrical energy use

Asynchronous machine. Main characteristics and operating principle. Equivalent electric circuit. Mechanical and electro-mechanical characteristics. Protections against over-currents. Electric safety. Protection against indirect contacts.

Readings/Bibliography

Macchine a Fluido T:

Cantore G.,“Macchine”, Progetto Leonardo, 1995 BO, 3a ed. 1999.

Minelli G., “Macchine idrauliche”, Pitagora, BO, s.d..

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

Cornetti G., “Macchine idrauliche”, Il Capitello, TO, 1989, 2a ed. 1991, rist. 1994.

Cornetti G., “Macchine termiche”, Il Capitello, TO, 1989, rist. 1994.

Ferrari G., “Motori a combustione interna”, il Capitello, Torino, 1992.

Minelli G., “Motori endotermici alternativi”, Pitagora, BO, s.d..

Negri di Montenegro G., Bianchi M., Peretto A.,“Sistemi energetici e loro componenti, Pitagora, BO, 2001, ISBN-88-371-1256-4.

Negri di Montenegro G., Moro D., Naldi G., “Corso di macchine - 1 Sistemi e componenti termici, Pitagora, BO, 1992, nuova ed. 1998.

Negri di Montenegro G., Naldi G., Peretto A., “Corso di macchine - 2 Macchine volumetriche Trasmissioni meccaniche”, Pitagora, BO, 1993.

Sandrolini S., Borghi M., Naldi G., “ Turbomacchine Termiche - Turbine”, Pitagora, BO, 1992.

Sandrolini S., Naldi G., “ Macchine 1: Fluidodinamica e termodinamica delle turbomacchine”, Pitagora BO, 1996, ISBN 88-371-0827-3

Sandrolini S., Naldi G., “ Macchine 2: Le turbomacchine motrici e operatrici”, Pitagora BO, 1997, ISBN 88-371-0862-1

Sandrolini S., Naldi G., “ Macchine 3: Gli Impianti motori termici e i loro componenti”, Pitagora BO, 2003, ISBN 88-371-1317

 

readings concerning Module 2:

Principi di ingegneria elettrica: 69726 - CONVERSIONE E UTILIZZAZIONE DELL'ENERGIA T Laurea in Ingegneria per l'ambiente e il territorio (9198)

G. Fabricatore, Elettrotecnica ed applicazioni, Ed. Liguori, 1994.

G. Rizzoni, Elettrotecnica: principi e applicazioni, McGraw-Hill, 3a edizione, 2013.

A.R. Hambley, Elettrotecnica, Pearson Paravia Bruno Mondadori, 4a edizione 2009.

Teaching methods

Topics are exposed by means of "chalk and blackboard"

Power Point presentations, when adopted, are available (download at Course web site)

Numerical calculations are also presented.

Assessment methods

Achievements will be assessed by the means of a final exam. This is based on an analytical assessment of the "expected learning outcomes" described above.

In order to properly assess such achievement the examination is composed of an oral session, which consist of a test, (duration 30÷45 min)

The oral session, consists normally of: three questions concerning topics indicated in the Program: Knowledge of plants lay-out, basic calculations and drawings of simplified machines architectures are required

Higher grades will be awarded to students who demonstrate an organic understanding of the subject, a high ability for critical application, and a clear and concise presentation of the contents To obtain a passing grade, students are required to at least demonstrate a knowledge of the key concepts of the subject, some ability for critical application, and a comprehensible use of technical language

A failing grade will be awarded if the student shows knowledge gaps in key-concepts of the subject, inappropriate use of language, and/or logic failures in the analysis of the subject.

(For Students of "Ingegneria per l'Ambiente e il Territorio" one question will concern topics on Module 2)

Teaching tools

Power Point presentations, when adopted, are available (download at Course web site)

Office hours

See the website of Giovanni Naldi

See the website of Pier Luigi Ribani