The course is devoted to present the main technologies for exploiting renewable Energy sources, the methods to correctly design the main parts of the installation, evaluate the useful energy which may be produced, make a cost-benefit analysis also taking into account environmental impact issues.

At the end of the course students should know the main technologies for exploiting renewable sources, and should be able to correctly design the main parts of an installation.

Basic knowledge about Physics, Thermodynamics, renewable energy sources and energy savings are required.

Calculation of solar radiation.

Position of the Sun in the sky and calculation of incidence angle between the Sun and the collector plane. Atmospheric models for clear and average skies. Data bases of horizontal solar radiation energy (UNI 10349). Calculation of global (direct, diffuse and reflected) irradiance and global solar irradiation on a tilted surface (UNI 8477).

Solar thermal installations.

Solar collectors typologies and definition of efficiency. Thermal balance of a solar collector and analysis of temperature profile of the plate. Hottel equation. Thermal and optical characterization of plate, glazed cover, ducts, and insulation.
The role of thermal storage and sizing criteria. Installation typologies, components and applications. Production of domestic hot water, space heating, swimming pools, solar dryers. Methods for the evaluation of seasonal performance of solar thermal installations. The f-chart method. Software for dynamic simulation of solar thermal installations: Polysun. Cost-benefit analysis.
Some hints on advanced topics:
• seasonal storage systems
• solar cooling through absorption refrigeration and passive solar systems.

Biomass and SUW (Solid Urban Waste).

Characterization of biomass fuel (wood, short rotation forestry, special crops, biogas from animal waste, etc.) as a commercial product, and under the energy, environmental and economic points of view. Main features and components of Heat and CHP (Combined Heat and Power) biomass generation installations. Solid Urban Waste. Emission control. Availability of biomass under its different forms with special attention on Piedmont situation.

Geothermal energy

Low enthalpy geothermal systems will be studied, both for free cooling or preheating techniques, and for ground-coupled heat pumps systems. A brief explanation of the main legal, technical and economic factors will be presented in order to carry on a feasibility analysis of such systems in the Italian climate.

Introduction to Concentrating Solar Power technologies
In this module a review of the main concentrating solar power technologies will be presented. The state of the art of each technology will be discussed, as well as the main physics principles, features and technical characteristics, together with an analysis of current and future R&D lines and trends. An overview of the commercial experiences worldwide will be given, addressing also the issue of the current cost of these technologies.

Motivation
- Utility-scale renewable energy production
- Cheap, efficient thermal storage and dispatchability

Solar Radiation
- Overview of radiation and solar spectrum
- Direct normal irradiance
- Sun shape and impact on optics

Principles and state of the art of the main technologies
- Parabolic Trough
- Central Receiver
- Linear Fresnel
- Parabolic Dish
- Thermal storage
- Solar chemistry and fuels

Components and Research Needs
- Mirrors
- Receivers (Cavity, External, Volumetric)
- Thermal storage (Sensible, Latent, Thermochemical)
- Power block and balance of plant

Main actors and key technology providers
- Commercial experiences worldwide
- Cost analysis (LCOE etc)

Modeling & Design tools
- Optics
- Thermal fluid dynamics
- Integration

Thesis opportunities

Exercises
Solar radiance calculation for a clear sky (ASHRAE model).
Solar collector energy balance and temperature distribution (transversal and longitudinal)
Integration of biomass and conventional fuel boiler for heat production

Projects
Preliminary design of solar thermal installation for domestic hot water production using Polysun software. Sensitivity analysis, cost-benefit analysis and calculation of optimal area.

• Notes from the teachers
• Duffie & Beckman, Solar Engineering of Thermal Processes, John Wiley & sons, 4th edition, New York 2013.
• Tiwari G.N., Solar Energy - Fundamentals, Design, Modelling, and Applications, CRC Press, 2002
• Bent Sorensen, Renewable Energy: Physics, Engineering, Environmental Impacts, Economics, Elsevier Associated Press, London, 2004.
• David Banks, An Introduction to Thermogeology: Ground Source Heating and Cooling, 2nd Edition. ISBN: 978-0-470-67034-7

Before sustaining the final examination students will have the opportunity to discuss an assignment consisting in the design of a solar thermal system using Polysun ® software. This assignment should be discussed before May 31. This will allow them to gain up to 4 points which will be added to the written examination results (28 points), so as to reach 32 points, corresponding to “30 cum laude”. For students not able to discuss this assignment before May 31 the maximum mark will be 28/30 points.

The written examination consists of a number of open questions and/or short exercises concerning:
· Solar thermal systems (STS)
· Biomass (BM)
· Concentrated Solar Power (CSP)

For what concerns Geothermal energy (GTE), a series of questions will be given with closed answers.

The details of the grading of the different parts are: 16 points (including 4 points for the assignment) for STS, 6 points each for CSP and GTE and 4 points for BM.