Politecnico di Torino
Politecnico di Torino
Politecnico di Torino
Academic Year 2016/17
Energy storage and trasmission
Master of science-level of the Bologna process in Energy And Nuclear Engineering - Torino
Teacher Status SSD Les Ex Lab Tut Years teaching
Chiavazzo Eliodoro ORARIO RICEVIMENTO A2 ING-IND/10 48 9 3 4 5
SSD CFU Activities Area context
ING-IND/10 6 D - A scelta dello studente A scelta dello studente
Subject fundamentals
Due to a continuous and inevitable depletion of fossil fuels, in addition to the great challenge of global warming, we nowadays witness an increasing interest towards renewable and sustainable energy sources. Among all others, solar energy is regarded to as one of the most promising for substituting traditional energy sources. However, the main problem with solar energy (and many other renewable energies) is its intermittent and unstable nature, which determines an undesired time mismatch between its availability and demand. Energy storage is a key technology to properly address this issue, thus enabling a much more extensive use and exploitation of natural and green energy resources.
In the introductory part of this course, we aim at providing an extensive and up-to-date overview of the disparate technology solutions which have been developed so far (both those that are already on the market and the ones that are still under investigations) for storing energy under diverse forms. Afterwards, we will particularly focus on thermal energy storage with a special emphasis on low-temperature thermal solar energy for civil applications.
More precisely, this course, through a series of theoretical lectures, discussion of case studies, numerical exercises in the labs and experimental activities on heat storage aims at providing students with all necessary competencies for properly choosing the storage technology which maximizes the exploitation of a given intermittent energy source.
We expect students to gain the essential know-how and tools for designing, sizing and analyzing (from both energy and cost perspective) the main components of storage plants.
Expected learning outcomes
First of all, this course aims at providing a wide overview on the different technologies so far developed for addressing the fundamental problem of energy storage, with a special focus on the most effective approaches for storing (low-temperature) heat.
Thanks to a number of theoretical lectures, the student has the opportunity of learning the basic principles and notions underlying the main components utilized in the energy storage devices. Those lectures will also help students to have a coherent vision of the matter and make an aware use of design tools that are discussed during the course. In fact, we expect students to acquire the ability of a quantitative design of storage systems (mostly sensible, latent and sorption thermal energy storage). Such an ability is essential for helping student in strengthening their problem-solving attitude (a very desirable skill of engineers). All this will be pursued by: 1) Case study discussion; 2) hands-on sessions during the numerical labs; 3) experiments in the heat storage lab; 4) solution of storage problems suggested by the lecturer (not mandatory).
Prerequisites / Assumed knowledge
Basic knowledge on heat transfer and applied thermodynamics.
The course can be sub-divided as follows:

1) Introduction and brief review of basic notions useful to the comprehension of energy storage phenomena (4.5 hours).
Brief overview of the course and a short review of the main heat transfer mechanisms, heat exchangers with and without fins. Brief review of some of the most important relationships in applied thermodynamics.

2) Energy storage in general (7.5 hours).
The importance of energy storage. Storage of mechanical energy: Compressed air and pumped hydro-storage plants. Flywheels. Electrochemical batteries. The issue of deep cycling, battery capacity and other main figure of merit of storage systems. Magnetic storage. Supercapacitors. Hydrogen production as an energy storage strategy.

3) Sensible heat storage (10.5 hours).
Direct and indirect heat storage plants. Materials and plant lay-out for sensible heat storage. First and second law efficiencies. Optimal size and storage period. Sizing of small sensible systems with water as storage material for solar applications. Common storage tanks. The importance of the temperature stratification. Simple design approaches for rock-beds. Simplified energy and exergy analysis of stratified sensible heat storage. Solar ponds. Numerical examples of sensible storage systems.

4) Latent heat storage (10.5 hours).
Classification of the most common materials for latent heat storage applications (organic, inorganic and eutectic). Short discussion on supercooling, segregation and cycling issues. Examples of phase-change-materials (PCM) available on the market. PCM for buildings: A brief discussion on the use of PCM for passive cooling applications. Some analytical and numerical modeling tools for PCM charging and discharging processes. The choice of the optimal PCM material. Numerical examples of latent storage systems.

5) Indirect heat storage: Physical and chemical sorption thermal energy storage - TES (10.5 hours).
The notion of inversion temperature. Closed and open sorption TES. Main thermodynamic transformations and relations describing sorption phenomena. Isosteric heat and isosteric field for a sorbent-sorbate pair. Adsorption isotherms. Discussion of ideal and real sorption heat storage cycles. Simplified models for describing sorption phenomena (Dubinin-Astakhov and Langmuir). Numerical examples of sorption heat storage systems.

6) Efficient transport of heat: modern approaches through micro- and nano-fluids (4.5 hours).
Brief discussion on nano-suspensions for heat transfer enhancement. A few elements on the energy transfer at the nanoscale. A brief discussion on micro-encapsulated phase-change materials for heat capacity enhancement. Percolating networks of nano-particles with high thermal conductivity for heat storage applications. Basic notions on classical molecular dynamics simulations.
Delivery modes
This course also includes the following activities:

1) Numerical lab: Macroscopic simulation (3 hours). Students will have the opportunity to use a commercial software (e.g. COMSOL or FLUENT) to simulate the charging/discharging process of sensible and latent heat storage systems.

2) Numerical lab: Microscopic simulation (3 hours). Students will have the opportunity of using an open-source software package (GROMACS) to simulate the heat transport within highly thermally conductive nano-particles (that are sometimes added to heat storage materials in order to enhance the overall thermal conductivity and thus the heat rate in charging/discharging processes).

3) Numerical lab: Microscopic simulation (3 hours). Students will have the opportunity of using an open-source software package (GROMACS) to simulate the adsorption process and the mass transport of water within solid sorbent materials, which are of interest for modern water sorption thermal storage systems.

4) Numerical lab: Experimental activities (3 hours). Students will have the opportunity to take part in some laboratory experiments, where solid sorbents for heat storage (e.g. hydrophilic zeolites) are charged and discharged. Simple calorimetric measurements will be also performed.
Texts, readings, handouts and other learning resources
All arguments discussed during this course will be covered by the material directly provided by the lecturer. In addition, the interested student can find below a list of References for possible further readings:

- I. Dincer, M.A. Rosen, "Thermal Energy Storage Systems and Applications", John Wiley & Sons, 2nd Edition, 2011.

- P. Asinari, E. Chiavazzo, "An Introduction to Multiscale Modeling with Applications", Esculapio, Bologna, 2013.

- A. Bejan, "Advanced Engineering Thermodynamic", John Wiley & Sons, 1997.

- A. Bejan, A.D. Kraus (Editors), "Heat Transfer Handbook", John Wiley & Sons, 2003.

- Matteo Fasano, Masoud Bozorg Bigdeli, Mohammad Rasool Vaziri Sereshk, Eliodoro Chiavazzo, Pietro Asinari, "Thermal transmittance of carbon nanotube networks: Guidelines for novel thermal storage systems and polymeric material of thermal interest", Ren. Sust. Energy Rev. 41, 2015.

- Eliodoro Chiavazzo, Matteo Fasano, Pietro Asinari, Paolo Decuzzi, "Scaling behaviour for the water transport in nanoconfined geometries", Nature Comm. 4565, 2014.

- Chiavazzo E., Asinari P., "Reconstruction and modeling of 3D percolation networks of carbon fillers in a polymer matrix" Int. J. Thermal. Sci. 49, 2010.

- Chiavazzo E., Asinari P., "Enhancing surface heat transfer by carbon nanofins: towards an alternative to nanofluids?" Nanosc. Res. Lett. 6, 2011.
Assessment and grading criteria
The examination is oral. In addition, students are also free to carry out a report on a heat storage plant design. The latter report is completely discretionary. However, only those that will present and discuss, during the oral examination, the report may gain extra 2 points (maximum) for the final mark. In the report a description of a heat storage plant (freely chosen or suggested by the lecturer), its sizing along with energy, exergy and economic analysis should be included relying upon the notions learned during the course. The minimum score to pass the exam is 18/30. Regardless of the optional report, everyone can potentially get the maximum mark (possibly cum laude).

Programma definitivo per l'A.A.2016/17

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