01TVHND

A.A. 2021/22

2021/22

Energy storage

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. One of the main problems with renewables though is its intermittent and unstable nature, which determines an undesired time mismatch between its availability and demand. Energy storage is a key technology to 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 specifically 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 aims at providing students with all necessary competencies for properly choosing the storage technology for an optimal exploitation of a given intermittent energy source. We expect students to gain the essential know-how and tools for designing, sizing and analysing (from both energy and cost perspective) the main components of storage plants.

Energy storage

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. One of the main problems with renewables though is its intermittent and unstable nature, which determines an undesired time mismatch between its availability and demand. Energy storage is a key technology to address this issue, thus enabling a much more extensive use and exploitation of natural and green energy resources. In the first 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. In the second part, we specifically focus on thermal energy storage with 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 possibly experimental activities (depends on availability during current year) aims at providing students with all necessary competencies for properly choosing and designing the storage technology for an optimal exploitation of a given intermittent energy source. We expect students to gain the essential know-how and tools for designing, sizing and analysing (from both energy and cost perspective) the main components of storage plants.

Energy storage

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 selected in collaboration with the lecturer (not mandatory).

Energy storage

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.

Energy storage

Basic knowledge on heat transfer, applied thermodynamics and chemistry.

Energy storage

Basic knowledge on heat transfer, applied thermodynamics and chemistry.

Energy storage

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 (9 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) Transport phenomena in energy storage problems (3 hours). A brief discussion on micro-encapsulated phase-change materials for heat capacity enhancement. Basic notions on classical molecular dynamics simulations. Percolating networks of nano-particles with high thermal conductivity for heat storage applications.

Energy storage

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) Discussion on basic notions about artificial photosynthesis and solar fuel generation; iii) State-of-the art electrochemical batteries; iv) Superconducting Magnetic Energy Storage (SMES) technology; v) Use of commercial softwares (i.e. COMSOL, Matlab, Simulink) for simulating energy storage problems.

Energy storage

Energy storage

Energy storage

Energy storage

Energy storage

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; - 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; - 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.

Energy storage

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.

Energy storage

**Modalità di esame:** Test informatizzato in laboratorio; Prova scritta (in aula); Prova orale obbligatoria; Elaborato progettuale in gruppo;

Energy storage

For all students, the examination consists in an oral test on the course topics including a discussion of a brief individual report carried out during the semester on one of the numerical labs. The examination takes about forty-five minutes and it is not allowed to use any educational materials for giving answers (in written form). Only those students who optionally carry out the individual project may possibly get an extra-bonus (in addition to the final mark) of max 2 points. The bonus is variable depending on the project quality and discussion during the examination. To pass the exam it is necessary to obtain an overall score greater than or equal to 18/30. Those who choose to be examined only on the basis of the oral test and the brief report on the numerical laboratories will be able to reach a maximum score of 29/30. Students who also carry out the optional project report can reach the maximum score of 30/30 (possibly 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 oral 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 from the oral 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 on the numerical laboratories.

Energy storage

**Exam:** Computer lab-based test; Written test; Compulsory oral exam; Group project;

Energy storage

The onsite examination will follow the exact same procedure as already described in the section on the blended mode with the difference that the first part of the exam shall be held onsite in a dedicated classroom or in a VLAIB. 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.

Energy storage

**Modalità di esame:** Elaborato scritto individuale; Prova scritta a risposta aperta o chiusa tramite PC con l'utilizzo della piattaforma di ateneo Exam integrata con strumenti di proctoring (Respondus);

Energy storage

The exam is performed through the Politecnico online platform “Exam” integrated with proctoring tools (Respondus) and it consists in a collection of maximum 27 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 possible support during the answers (provided that during the environmental recording and the later use are clearly showed in the webcam). It will be possible to close the exam and finish if at least 90% of the total time has elapsed. The Virtual Classroom integrated in the Exam platform will be also enabled in order to allow possible interaction with the lecturers during the exam. 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 27 points are assigned to students who give correct and complete answers to all questions. Whenever needed the upper-rounded mean rule will be applied. In addition to the online exam, a mandatory individual report on the numerical labs is requested to students, who will have to complete and upload their reports on the Politecnico portal (in the section “Elaborati”) at least one week before the chosen exam date. Each student can choose to prepare the report only on one of the attended laboratory topics. This report on the numerical lab will be evaluated with a score equal to 1 (sufficient), 2 (good), 3 (very good) or 4 (excellent), which will be added to the score of the online exam. To pass the exam it is necessary to obtain an overall score greater than or equal to 18/30. Students who possibly exceed the grade of 30/30 will be assigned 30 cum laude. Specifically, the exam aims at assessing the achievement of the following objectives: 1. Theoretical knowledge underpinning the functioning of the technologies developed for energy storage and transport; 2. Ability to select and to perform a preliminary sizing/design of a storage technology suitable for coping with real energy storage problems; 3. Ability to accurately estimate the expected performance of key components for energy storage technologies (with particular emphasis on thermal energy). The above items are established either through questions from the online exam or through the reports;

Energy storage

**Exam:** Individual essay; Computer-based written test with open-ended questions or multiple-choice questions using the Exam platform and proctoring tools (Respondus);

Energy storage

The exam is composed of two parts. The first part is performed through the Politecnico online platform “Exam” integrated with proctoring tools (Respondus) 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 (provided that during the environmental recording and the later use are clearly showed in the webcam). It will be possible to close the exam and finish if at least 90% of the total time has elapsed. The Virtual Classroom integrated in the Exam platform will be also enabled in order to allow possible interaction with the lecturers during the exam. Each correct answer provides 1 point; each unanswered questions is assigned 0 point; 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. Whenever needed the upper-rounded mean rule will be applied. This part is will be considered sufficient if at least 12 points out of 23 are obtained. 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 lecturers). 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. The report on the group-project will be evaluated with a score ranging from 0 (insufficient) up to 10 (excellent) and added to the score of the part done via the “Exam” platform to all group members. This part is considered sufficient if at least 6 points out of 10 are obtained. The final mark will be the sum of the two above partial scores and it is considered passed if greater or equal to 18 with both parts being sufficient. Students who possibly exceed the grade of 30/30 will be assigned 30 cum laude. Specifically, the exam aims at assessing the achievement of the following objectives: 1. Theoretical knowledge underpinning the functioning of the technologies developed for energy storage and transport; 2. Ability to select and to perform a preliminary sizing/design of a storage technology suitable for coping with real energy storage problems; 3. Ability to accurately estimate the expected performance of key components for energy storage technologies (with particular emphasis on thermal energy). The above items are established either through questions from the online exam or through the reports.

Energy storage

**Modalità di esame:** Prova orale obbligatoria; Prova scritta a risposta aperta o chiusa tramite PC con l'utilizzo della piattaforma di ateneo Exam integrata con strumenti di proctoring (Respondus); Elaborato progettuale in gruppo;

Energy storage

The exam is performed through the Politecnico online platform “Exam” integrated with proctoring tools (Respondus) and it consists in a collection of maximum 27 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 possible support during the answers (provided that during the environmental recording and the later use are clearly showed in the webcam). It will be possible to close the exam and finish if at least 90% of the total time has elapsed. The Virtual Classroom integrated in the Exam platform will be also enabled in order to allow possible interaction with the lecturers during the exam. 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 27 points are assigned to students who give correct and complete answers to all questions. Whenever needed the upper-rounded mean rule will be applied. In addition to the online exam, a mandatory individual report on the numerical labs is requested to students, who will have to complete and upload their reports on the Politecnico portal (in the section “Elaborati”) at least one week before the chosen exam date. Each student can choose to prepare the report only on one of the attended laboratory topics. This report on the numerical lab will be evaluated with a score equal to 1 (sufficient), 2 (good), 3 (very good) or 4 (excellent), which will be added to the score of the online exam. To pass the exam it is necessary to obtain an overall score greater than or equal to 18/30. Students who possibly exceed the grade of 30/30 will be assigned 30 cum laude. Specifically, the exam aims at assessing the achievement of the following objectives: 1. Theoretical knowledge underpinning the functioning of the technologies developed for energy storage and transport; 2. Ability to select and to perform a preliminary sizing/design of a storage technology suitable for coping with real energy storage problems; 3. Ability to accurately estimate the expected performance of key components for energy storage technologies (with particular emphasis on thermal energy). The above items are established either through questions from the online exam or through the reports;

Energy storage

**Exam:** Compulsory oral exam; Computer-based written test with open-ended questions or multiple-choice questions using the Exam platform and proctoring tools (Respondus); Group project;

Energy storage

The exam is composed of two parts. The first part of the exam is performed through the Politecnico online platform “Exam” integrated with proctoring tools (Respondus) 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 (provided that during the environmental recording and the later use are clearly showed in the webcam). It will be possible to close the exam and finish if at least 90% of the total time has elapsed. The Virtual Classroom integrated in the Exam platform will be also enabled in order to allow possible interaction with the lecturers during the exam. 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. Whenever needed the upper-rounded mean rule will be applied. 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 lecturers. 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 10 (excellent) assigned and added to the score of the online part (and can be different for different members of the same group). This part is considered sufficient if at least 6 points out of 10 are obtained. 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 with both parts being sufficient. Students who possibly exceed the grade of 30/30 will be assigned 30 cum laude. Specifically, the exam aims at assessing the achievement of the following objectives: 1. Theoretical knowledge underpinning the functioning of the technologies developed for energy storage and transport; 2. Ability to select and to perform a preliminary sizing/design of a storage technology suitable for coping with real energy storage problems; 3. Ability to accurately estimate the expected performance of key components for energy storage technologies (with particular emphasis on thermal energy). The above items are established either through questions from the online exam or through the reports.

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Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY