OVERVIEW

The course aims to provide students with the necessary knowledge for the proper use of the basics of technical thermodynamics and heat transfer in the context of energy conversion systems.

AIMS AND CONTENT

LEARNING OUTCOMES

Basic knowledge of applied thermodynamics; thermodynamic diagrams for gases and vapors and their practical use; elementary study of the main direct and inverse thermodynamic cycles; rudiments of heat transfer with particular regard to thermal conduction.

AIMS AND LEARNING OUTCOMES

Operational skills

At the end of the course the student will have understood the fundamental principles of thermodynamics and heat tranfer.

He will be able to apply these principles to the resolution of elementary problems of thermodynamics of fluids (gases, liquids, two-phase), and heat tranfer.

He will be able to carry out "first principle" analysis of energy conversion plants, direct and inverse: choice of the cycle, overall sizing (mass flow rate), functional sizing (heat balances).

He will be able to make comparisons between different possible solutions and to evaluate measures for the improvement of the performance of said plants.

The course contributes to the achievement of the 2030 Agenda "sustainable development goals", contributing in particular to the 4-7-9-11-13 goals

PREREQUISITES

Basic notions of mathematics and physics

TEACHING METHODS

Lectures and final exam (via Teams)

Lessons will be held in presence, except in case of emergency situations

SYLLABUS/CONTENT

This course provides an introduction to the essential theoretical basis of engineering thermodynamics and its application to a range of problems of relevance to practical engineering:   thermodynamic properties of working fluids including enthalpy and entropy; First Law of Thermodynamics applied to common engineering situations; Second Law of Thermodynamics applied to heat engines and refrigeration systems; common practical heat engine and refrigeration cycles. The course aims to equip students with basic tools and methodologies for carrying out thermodynamic analyses of engineering systems.

The course also provides elements of heat transfer, in particular heat conduction.

IN DETAIL

Thermodynamics

• Definition of a thermodynamic system - state - state variables - system/external interactions. Concept of thermodynamic equilibrium. Thermodynamic transformations (processes).

• Exchange of work and heat. Total energy as a state function. First law of thermodynamics for closed systems, cyclic steady-state systems, and steady-state open systems. Total work, compression work, and net external work. State function enthalpy and its properties.

• Concept of reversibility in thermodynamic transformations. Spontaneous transformations. Second law of thermodynamics: Clausius inequality and its consequences on the possibility of energy conversion. State function entropy.

Thermodynamic fluids Equations of state: ideal gas, real gas, use of tables.

• Two-phase mixtures in equilibrium: quality and specific volume.

• State diagrams. Saturated and superheated vapor tables. Expression of internal energy, enthalpy, and entropy.

• Study of major thermodynamic transformations in ideal gases and saturated vapor (isothermal, isobaric, isochoric, adiabatic) in the p-v, T-s, p-h planes.

Technological processes of energy conversion

• Thermodynamic analysis of energy conversion processes. Representation of a thermodynamic cycle. Utilizable and utilized fractions. Structure of a Carnot cycle. Multiplicity of thermal sources. Role of source temperatures.

• Representation of a inverse cycle, specific refrigeration effect, COP (Coefficient of Performance).

• Some real transformations. Isentropic efficiencies of the expander and the compressor. Physical meaning.

Closed loop systems

• Gas engine plants: Brayton's reference cycle. Utilization fraction as a function of the compression ratio. Expression of useful work. Dependence of useful work and utilization fraction on the operating point. Methods to increase the utilization fraction. Physical and economic limits hindering the increase of the utilization fraction.

• Steam engine plants: Analysis of state parameters and state functions in the various components of a steam engine plant. Expression of the utilization fraction for the steam engine plant and its optimization. Physical and economic limits hindering the increase of the utilization fraction.

• Vapor compression refrigeration systems: Representation of transformations in different thermodynamic planes. Methods to enhance the performance of refrigeration cycles. Brief overview of compound cycles. Qualitative introduction to the absorption refrigeration system.

Elements of fluid dynamics -

• Bernoulli's equation from the first law of thermodynamics. Physical meaning of various terms. Brief overview of viscous friction phenomena.

Introduction to heat transfer

• Fourier's law of conduction for isotropic and homogeneous materials.

• Concept of thermal resistance for one-dimensional conduction in flat (and cylindrical, briefly) geometry. Analogy with Ohm's law.

• Heat flow in convection. Newton's law. Classification of convection. Concept of heat transfer correlations for natural and forced convection.

• Characteristics of radiative energy transport. Brief overview. Emissivity and absorption coefficient.

• Heat exchangers: General concepts. Mixing and surface heat exchangers. Temperature distribution. Efficiency.

RECOMMENDED READING/BIBLIOGRAPHY

Course-related resources will be provided on the AulaWeb site, which is accessed through unigepass at https://2024.aulaweb.unige.it/course/edit.php?id=3211

This material include lecture material, course notes, sample exam  problem sheets and solutions.

M.J. Moran, H.N. Shapiro: Fundamentals of Engineering Thermodynamics, John Wiley and Sons, Inc, 1993

TEACHERS AND EXAM BOARD

LESSONS

LESSONS START

https://corsi.unige.it/8722/p/studenti-orario

Class schedule

The timetable for this course is available here: Portale EasyAcademy

EXAMS

EXAM DESCRIPTION

The assessment tests are oral and distributed over 7 sessions in the months of January, February, June, July, and September. The dates are available online (by October). Specific details on the various tests are available on aulaweb

Students who have valid certification of physical or learning disabilities on file with the University and who wish to discuss possible accommodations or other circumstances regarding lectures, coursework and exams, should speak both with the instructor and with Professor Federico Scarpa (federico.scarpa@unige.it), the Polytechnic School's disability liaison

ASSESSMENT METHODS

The first question, a technical one, aims, in accordance with the training objectives (detail), to ascertain the ability of the student to solve elementary problems of thermodynamics (usually the analysis of a couple of transformations, part of a more complex cycle, direct or inverse). The test continues by verifying the ability and understanding of the student to manage mass and energy balances and generally to master all the elements of the first and the second principles provided during the course. The assessment also aims to verify the level of maturity achieved by the student in correctly assessing different solutions and in proposing variants and measures suitable for improving the performance of the system in question (steam or gas engine or refrigerator).

FURTHER INFORMATION

https://2023.aulaweb.unige.it/course/view.php?id=10157