The aim of the course is to ensure that the student (1) learns and acquires the reasons underlying the particular characteristics of the renewable energy sources; (2) understands the ways of a proper choice of the devices and of the technical and economic design (albeit preliminary) for the systems of energy conversion and of the production of electricity through the use of renewable energies.
The course presents and discusses the main technologies for the conversion of the so-called "renewable energies": solar energy (direct, biomass, wind), geothermal energy. A brief discussion is also reserved to the forms considered less traditional: ocean waves, sea currents and tides, OTEC plants.
Wide part of the course is devoted to solar power (thermal, photovoltaic and thermal), even with a thorough analysis of the radiation availability at ground level and of the methods for its estimation. We discuss also the peculiarities of geothermal sources and of the systems that allow his exploitation for the production of electricity. The analysis of the use of wind turbines is accompanied also by a description of the methods of the assessment of the availability of the wind energy resource.
Where possible, space is also dedicated to the presentation and discussion of technical and economic analysis of typical conversion systems.
- Quantification of the perennial energy sources potential The solar energy. The biomass production. The wind energy. The geothermal energy. The ocean temperature gradient. Ocean waves and Tides. - Classification and use of the perennial energy sources The thermal uses. The production of the electrical energy. Other uses.
- The Solar Energy Incoming solar radiation and climatic data. Flat-plate and focusing collectors. The solar ponds. The pointing methods of the focusing collectors. The running of the solar collector fields. Evaluation of the performances of the solar collectors. Thermal energy storage. The production of electrical energy by thermal energy. Operating and control criteria. Simulation of plants. Examination of realized plants: performances and costs discussion. Photovoltaic energy conversion. Working principles of the photovoltaic cells. Silicon and thin-film solar cells. The photovoltaic modules. The characteristics of the photovoltaic modules. Controls criteria. Examination of some realized plants: performances and economic discussion.
- The Biomass Energy The characteristics of the vegetable biomass: typical composition, the effect of the humidity, the main conversion technologies. The combustion and gasification in the plants for electricity production by biomass. The Rankine engines with organic fluid as working fluid. Examples of typical biomass power plants.
- The Geothermal Energy Anomalous thermal gradients in the earth’s crust, hydrothermal systems, geo-pressured systems, hot dry rocks. Exploitation of the geothermal energy. The electrical energy plants (vapour plants, flashed steam systems, binary cycles). Controls criteria of the geothermal plants.
- The Wind Energy Evaluation of the power of the wind turbines: the impulsive theory. The minimum, the design and the maximum power of a wind turbine. Power- velocity characteristics of wind turbines. Connection problems with the electric grid. Economic aspects and the optimum size power
- Other Renewable Energy Sources Discussion of the basic principles and a brief presentation of some research and prototype plants.
The books in the following list are all relevant and of general and specific interest for the course. F.P. Califano, V. Silvestrini, G. Vitale, La progettazione dei sistemi fotovoltaici, Liguori Editore, Napoli, 1984. J.A. Duffie, W. A. Beckman, Solar Engineering of Thermal Processes, John Wiley & Sons, New York, Second Edition, 1991
P.Gipe, Wind Power, Renewable Energy for Home, Farm, and Business, Chelsea Green Publishing Company, White River Junction, Vermont, 2004. T. Markvart, Solar Electricity, John Wiley & Sons, Chichester, Unesco Energy Engineering Series, Second Edition, 2000.
G. Comini, S. Savino, La captazione della energia solare, International Center for Mechanical Sciences - Monografie CISM, Udine, Ottobre 2013 R.Pallabazzer, Sistemi di conversione eolica - La tecnologia delle moderne macchine del vento, Hoepli Editore, Milano, 2011.
R. DiPippo, Geothermal Power Plants - Principles, Applications, Case studies and Environmental Impact, Elsevier, Amsterdam, Second Edition, 2008 J.W. Tester, M. Modell, Thermodynamics and Its Applications, Prentice Hall PTR, Upper Saddle River, New Jersey, 3rd Edition, 1997.
E.P. Gyftopoulos, G. P. Beretta, Thermodynamics - Foundations and Applications, Dover Publications, Mineola, New York, 2005. C. M. Invernizzi, Closed Power Cycles. Thermodynamic Fundamentals and Applications, Lecture Notes on Energy, 11, Springer - Verlag, London, 2013
The lectures will be delivered in the classroom using educational material (presentations, lecture notes, fact sheets) made available, from time to time, by the teacher to the students . The lessons will always be accompanied by numerical applications related to concrete cases and during the year we will try to do at least a technical visit.
Where possible, the students will be directly involved in the solution of some significant problems: carrying out appropriate exercises in the classroom, as short lab reports.
Learning occurs through the direct involvement of students in the solution of problems and exercises during the lessons. . At the end of the course the student will take an oral examination.