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. We expect students to acquire the ability of a quantitative design of storage systems. 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 (depends on availability during current year); 4) analysis and design of storage problems selected in collaboration with the lecturer.

Basic knowledge on heat transfer, applied thermodynamics and chemistry.

The course can be sub-divided as follows: 1) Introduction and brief review of basic notions useful to the comprehension of energy storage phenomena (5% of total time). 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) Mechanical Energy storage systems (10% of total time). The importance of energy storage. Storage of mechanical energy: Compressed air and pumped hydro-storage plants. Flywheels. Energy storage in gaseous springs. Gravity energy storage. Lumped parameter modelling of mechanical energy storage systems. 3) Electro-chemical energy storage systems (12.5% of total time) Electrochemical batteries. The issue of deep cycling, battery capacity and other main figure of merit of storage systems. Magnetic storage. Electric double-layer theory and supercapacitors. Hydrogen production as an energy storage strategy. Lumped parameter modelling of electrochemical energy storage. Short notice on photo-electro-conversion of solar radiation. 4) Sensible heat storage (17.5% of total time). Direct and indirect heat storage plants. Materials and plant layout 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. Lumped-parameter modelling of sensible storage systems. 5) Latent heat storage (17.5% of total time). 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. 6) Indirect heat storage: Physical and chemical sorption thermal energy storage - TES (17.5% of total time). 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. 7) In-depth seminars on energy storage related issues (20% of total time). Students attending this course will benefit of a number of in-depth seminars on energy storage related issues including: i) Energy materials modelling by molecular dynamics simulations; ii) State-of-the art electrochemical batteries; iii) Superconducting Magnetic Energy Storage (SMES) technology; iv) Use of commercial softwares (i.e. COMSOL, Matlab, Simulink) for simulating energy storage problems.

All arguments discussed during this course will be covered by a large variety of 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; - R. Schloegl (ed), Chemical Energy Storage, De Gruyter, 2013; - Butt, H. J., Graf, K., & Kappl, M. Physics and chemistry of interfaces. John Wiley & Sons, 2013. - Callen, H. B. Thermodynamics and an Introduction to Thermostatistics, 1998. - 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; Further readings: - Neri, M., Chiavazzo, E., & Mongibello, L., Numerical simulation and validation of commercial hot water tanks integrated with phase change material-based storage units. Journal of Energy Storage, 32, 101938 (2020). - 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; - 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.

Lecture slides; Exercise with solutions ; Video lectures (previous years); Self-assessment tools;

Exam: Written test; Compulsory oral exam; Group project;

The exam is composed of two parts. In an suitable classroom of the university, the first part of the exam is performed through the Politecnico online platform “Exam” and it consists in a collection of maximum 23 questions (both multiple choice questions and open-ended questions) which will focus on: • Fundamental aspects of the course topics aiming at assessing that the student has understood the theoretical foundations on energy storage technologies; • Practical aspects of the course topics aiming at assessing the understanding and ability in using the analysis tools of energy storage technologies on specific cases. It will be possible to navigate freely through the questions and, if needed, to use a calculator (either from the LockDown browser or a physical one). The total time of the written exam will be at least 90 minutes, and it is not allowed to use any educational materials or other external support during the exam. It is permitted to have and use only three blank A4 papers and a pen (black or blue) and possibly a physical calculator as a support during the answers. Each correct answer provides 1 point; unanswered questions are assigned 0 point each; each wrong answer provides a penalty of -0.2 points (except for open-ended questions, where no penalties are applied and a mark between 0 (min) and 1 (max) will be assigned depending on completeness of the answer). The score of the written exam is assigned in such a way that a maximum of 23 points are assigned to students who give correct and complete answers to all questions. A minimum score of 10 points should be reached in the first part to be allowed to give the subsequent part of the exam. The second part is based on a mandatory group-project report (developed during the semester) on the design of an energy storage system as assigned and tutored by the lecturer is requested. Each group will have to complete and upload the report on the Politecnico portal (in the section “Elaborati”) at least one week before the chosen exam date. Each student will have to answer to specific questions during an oral face-to-face discussion with the examiner. This part will be evaluated and a score ranging from 0 (insufficient) up to 8 (excellent) assigned and added to the score of the online part (and can be different for different members of the same group). The discussion of this part will last around 15 minutes, and it is not allowed to use any educational materials except for a copy of the report itself. The final mark will be the sum of the two above partial scores and it is considered passes if greater or equal to 18. Students who possibly exceed the grade of 30/30 will be assigned 30 cum laude. Specifically, the exam aims to assess the achievement of the following objectives: 1. Theoretical knowledge underpinning the functioning of the technologies developed for energy storage and transport. This is established through questions during the first part of the exam; 2. Ability to select and to perform a preliminary sizing/design of a storage technology suitable for coping with real energy storage problems. This is established either through questions in the first part of the exam or through the report; 3. Ability to accurately estimate the expected performance of key components for energy storage technologies (with particular emphasis on thermal energy). This is established by carrying out the report.

In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.