B2385 - Exergy and Pinch Point Analysis for Sustainable Energy Use

Learning outcomes

On completion of this course, the student will be able to calculate entropy generation and Energy losses in a thermodynamic/energy system; determinie conditions leading to minimal entropy generation in a system; make the necessary assumptions on system definition, operating conditions etc. required to carry out a consistent Energy analysis, suggesting possible improvements; calculate Energy content, reversible work, isentropic efficiency, Energy loss and irreversibility and energy efficiency for different parts of an energy system; apply the Energy analysis method to energy systems; calculate adiabatic flame temperature and Energy loss in combustion processes; determine the pinch temperature and the minimal required thermal load for a suitable industrial process; design heat exchanger networks according to the principles of pinch analysis; suggest measures to reduce heating and cooling needs in an existing heat exchanger network; evaluate pros and cons of traditional and renewable energy sources within the framework of sustainable energy use.

Course contents

Thermodynamic methods for efficient and effective energy use: entropy generation minimisation and
exergy analysis. Definition of exergy, dead state, thermodynamic equilibrium, reference conditions,
extended system and immediate surrounding, entropy generation in interface, entropy, energy and
exergy balance equations for closed and open systems, and
exergy as non-state function. Equations for energy content and exergy change for closed system, open
system with stationary flow and heat exergy in the Carnot model. Exergy loss and energy
efficiency (Second Law Efficiency) for technological processes and cycles. Exergy analysis
for mixture and separation processes such as desalination and carbon dioxide separation. Exergy
analysis for combustion processes.

Exergy analysis for components and systems heat exchangers, vapour power plants, gas turbines, cogeneration, geothermal power plants, fuel cells, Photovoltaic systems, solar thermal systems, wind turbines.

Exergy in processes: refrigeration and liquefaction, drying, desalination, transportation and buildings.
Exergy and sustainability.

Pinch point analysis.

Basic concepts such as pinch temperature, minimal need of external heating and cooling, composite
curves and GCC (Grand Composite Curve),  energy targeting, exemplified through current research and literature. Design of heat exchanger networks according to energy targeting.

Readings/Bibliography

The lectures follow two texts: "E.Michelides - Exergy Analysis for Energy Conversion Systems,  Cambridge  university Press, 2021" for the exegy analyisis,  and "I. Kemp - Pinch Analysis and Process Integration, 2nd Edition,Butterworth and Heinemann, 2006", for the pinch point method. Additional material will be made available on the Virtuale Platform as required.

The following is a list of suggested literature for the interested reader.
- Kotas – The Exergy Method of Thermal Plant Analysis
- Bejan, Tsatsaronis, Moran - Thermal Design and Optimization
- Kemp - Pinch Analysis for Energy and Carbon Footprint Reduction
- Rutledge - Energy. Supply and Demand.
- Sala Lizarrga, Picallo-Lopez - Exergy Analysis and Thermoeconomics of Buildings.

Teaching methods

Instruction is in the form of classroom lectures. All subjects are also illustrated through numerical exercises, which are solved during class.

Assessment methods

Attendance of classes is strongly recommended in order to get firm understanding of the subject, yet it is neither compulsory nor significant in the determination of the final grade, as this is solely based on the candidates' performance during theexamination.

Assessment is individual and based oral examinations consisting of a numerical problem and two questions pertaining on the subjects discussed during the lectures. The only allowed material for the solution of the exercise is the pocket calculator; if tables are needed (e.g. thermodynamic tables), these are provided during the test.

If students have a decision from Bologna University entitling them to Targeted Study Support due to a documented disability, the examiner has the right to give such students an adapted examination or to examine them in a different manner.

Successful completion of the course entitles to a grade from 18 (Pass) to 30 with Merit (Distinction); corresponding grades (e.g. Distinction/Pass with some Distinction/Pass) for international students may be awarded upon request.

Teaching tools

Numerical exercises during lectures. Blackboard, PC, projected slides.

All teaching material used in the lessons is made available on the online page of the course through https://virtuale.unibo.it

Office hours

See the website of Marco Lorenzini