panel 2: thermal storage · 2. thermal storage 2.1 descripción in the framework of energy storage,...

Panel 2: Thermal Storage

Scope of discussion, background and Guiding questions

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INEEL noviembre 2017

Contenido

2. THERMAL STORAGE ................................................................................................................ 4

2.1 Descripción ........................................................................................................................ 4

2.2 Thermal Storage with Phase Change Materials (PCM´s) ................................................... 4

2.2.1 State of the art and technique .......................................................................................... 4

2.2.2 Implementation experiences ............................................................................................ 6

2.2.3 Advantages and disadvantages ......................................................................................... 7

2.2.4 Maturity ............................................................................................................................. 8

2.2.5 National Context ............................................................................................................... 9

2.2.6 Challengues ....................................................................................................................... 9

2.3 Guiding Questions ............................................................................................................. 9

2.4 Figures ............................................................................................................................. 10

2.3 References ....................................................................................................................... 13

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2. THERMAL STORAGE

2.1 Descripción

In the framework of energy storage, the work table corresponding to the topic of the heat tray focuses on 3 main aspects: Context of thermal storage in Mexico, Use of materials with phase change of the thermal process (industry and electrical network) and the priorities of thermal storage in Mexico. There will be a panel made up of experts in the subject, the coordinators by a moderator will unify criteria on the state of the art, advantages and disadvantages, costs, level of maturity; define the challenges of the improvement, the design parameters of the main thermal protection systems, the storage capacity, the loading and unloading cycles; The applications in the electrical network, demonstration, pilot or commercial projects will be analyzed, as well as the requirements of human capital and infrastructure. The main objective of this work table is to establish the feasibility of the implementation and development of each technology in the national context and propose strategies for short, medium and long term for their habilitation by establishing priorities in the national electricity system.

2.2 Thermal Storage with Phase Change Materials (PCM´s)

2.2.1 State of the art and technique

The Phase Change Materials (PCM) are used for the storage of energy like latent heat. They are an important class of materials that contribute substantially to the efficient use and conservation of waste heat and solar energy. Latent heat storage provides a higher density of thermal storage with a lower temperature difference between stored and released heat than the sensible heat method [1].

The application of PCMs for thermal storage reduces the decoupling between generation and demand, improving the performance and reliability of energy distribution networks and playing an important role in energy conservation [2]. PCMs have a high enthalpy of fusion with the ability to store or release large amounts of energy as latent heat during melting and solidification, in relatively small volume. The ideal PCM must meet certain criteria related to desirable thermophysical, kinetic and chemical properties. Among the thermal properties can be mentioned the following [2]:

A melting temperature within the desired operating range

A high latent heat of phase transition per unit volume

High specific heat, to provide additional sensitive heat storage

High thermal conductivity in both phases to achieve efficient heat transfer As physical properties we look for:

A small volume change during phase transformation

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Low vapor pressure at operating temperature

Favorable phase balance

Congruent fusion, avoiding the irreversible separation of its components

High density Kinetic properties:

Do not present super cooling

High nucleation speed

An adequate crystallization rate Chemical properties:

Long-term chemical stability

Completely reversible freezing / melting cycle

Compatibility with construction materials

No corrosive influence on construction materials Must be non-toxic, non-flammable and non-explosive to ensure safety PCMs have to be available in large quantities and at low cost. In general, the above criteria are not met in most PCMs. However, the latest elements in the design and new materials for energy storage, including nano materials, have the potential to improve their performance with longer lifetimes [2]. The relationship between the fundamental structure and energy storage properties of PCMs has been critically examined to determine the heat accumulation / emission mechanisms with reference to their final energy storage characteristics. The PCMs are grouped into 3 large groups, Organic (paraffin compounds and non-paraffin compounds), Inorganic (hydrated and metallic salts) and Eutectic (organic-organic, Inorganic-inorganic, inorganic-organic). Based on the temperature ranges at which the phase transition occurs, the PCMs can be divided into 3 main groups: Low temperature PCMs. Their phase transition temperatures correspond to magnitudes below 15 ° C, usually used in air conditioning applications and in the food industry. Medium temperature PCMs. Being the most popular, they have phase transition temperatures in the range of 15-90 ° C their main applications are in solar energy, medical, textile, electronic and energy saving applications in buildings and industry as a means of utilization of residual heat. High temperature PCMs. With a phase transition above 90 ° C developed mainly for industrial, solar and aerospace applications. [3] Many materials have been investigated during the technical evolution of PCMs, including inorganic systems (salts and hydrated salts), organic compounds such as paraffins or fatty

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acids and polymeric materials (polyethylene glycol). PCM can be classified by the phase transition mode: gas-liquid, solid-gas, solid-liquid and solid-solids. See Figure 2.3.1. Because of their significantly smaller volume changes, generally 10% or less, solid-liquid and solid-solid PCMs have greater applications in thermal storage, since this characteristic makes them economically and practically attractive. Generally the solid-solid phase transition heat is lower than the solid-liquid phase, however, the use of the first group of materials can avoid the problems of PCM leakage at phase transition temperatures, a significant technical problem with PCMs solid-liquids. Solid-solid PCMs use phase transition heat from one crystalline form to another and can be considered as an alternative to solid-liquid PCMs. In addition to the various applications that PCMs have in sectors such as biomedical, electronic, textile, construction, automotive industries, special attention has been paid to improving their thermal conductivity, encapsulation methods and stabilization procedures.

2.2.2 Implementation experiences

The applications of the PCMs are presented in the construction industry, textile, automotive and solar energy facilities. In recent years, a growing number of applications have emerged in the fields of electronics and medicine. Application in heat transfer thermal fluids In recent years, research on latent functional thermal fluids (LFTFs) or 2-phase heat transfer fluids has increased because they provide a greater apparent specific heat in the phase change temperature range, compared to single-phase heat transfer fluids. The LFTFs are composed of PCM particles and heat transfer fluids, they can exist as a suspension of phase change microcapsules or a phase change emulsion. Its use can significantly improve the heat transfer rate between the fluid and the tube wall, reduce the mass flow rate and the energy consumption of the required pump. Therefore, LFTFs have many potentially important applications for heating, ventilation, air conditioning, refrigeration and heat exchangers. [4] Application in energy storage In the solar sector, efforts have been made in recent years to use PCMs in solar thermal energy systems, where the main need is the storage of heat during the day and its use at night. The studies have focused on the evaluation of key aspects of heat transfer and its behavior in large-scale units. In this area the following advances can be mentioned: Kurklu et al. [5] developed a solar collector combining a PCM and water, which can be an alternative to traditional solar water collectors, provided that the absorption and characteristics of the collector insulation are improved. Hammou et al. [6] proposed a thermal storage system with materials with phase change to manage the storage of heat for solar and electric energy. The simulations carried out

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during a period of 4 consecutive winters indicated that the system reduced the energy consumption used in space heating by almost 32%. Generally, the storage in plants with parabolic cylinder technology uses direct systems of 2 storage tanks with molten salts. The need to reduce costs in the system has led to proposals such as the use of latent heat storage devices in cascade, whose main feature is the use of minimum storage material. Recent studies favored the storage of latent heat in cascades and concrete regenerators. The positive effect of the application of latent thermal storage systems in cascade compared with conventional latent heat storage was verified experimentally and numerically [7]. See figure 2.3.2. Adinberg et al. [8] proposed, developed and tested a reflux heat storage system to produce superheated steam over a temperature range of 350-400 ° C with a Zinc-Tin alloy, acting as the PCM. A high temperature transfer fluid is added to the storage medium to improve the heat exchange within the system, which comprises PCM units and the associated heat exchangers serving for the loading and unloading of the storage system. Laing et al. [9] tested a prototype of a thermal storage unit (Fig. 3) with aluminum fins filled with 140 Kg of sodium nitrate. It was operated for 172 cycles (more than 4000h) with which it was found that the PCM did not suffer decomposition or there was degradation in the fins. The prototype was scaled to 14 tons of NaNO3. The PCM storage module is combined with 2 sensitive concrete storage modules and will be tested in steam generation facilities under real steam conditions in Spain. [10] The two concrete modules are used for preheating and overheating the water / steam. The German Aerospace Center (DLR) has conducted intensive research on sodium nitrate (NaNO3) as PCM. NaNO3 is the most suitable candidate to generate steam at a pressure of around 100 bar in direct steam generation technologies. It has a commercial latent heat storage system whose main applications include direct steam generation (DSG), solar concentration plants (CSP) and heat recovery from industrial processes. Figure 2.3.5 [11]. The University of Lehigh proposes a thermocline installation for the evaluation of encapsulated PCMs (EPCMs) at temperatures above 400 ° C with applications in solar concentration plants. The storage medium was NaNO3, stainless steel capsules were used to contain the sodium nitrate, which were manufactured and installed in a pilot scale thermal energy storage system. Compressed air was used as heat transfer fluids in the tests. The test section successfully demonstrated the ability to transfer thermal energy to and from a transport fluid, achieving storage and energy recovery in multiple loading and unloading cycles. See Figure 2.3.7 [12]

2.2.3 Advantages and disadvantages

Each type of PCM has advantages and disadvantages to each other, some of which are listed below:

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Table2.3.1. Advantages and disadvantages of PCMs

Organic PCM Inorganic PCM

Advantages • Non-corrosive • They do not present subcooling • Thermal and chemical stability

• Great enthalpy in phase change

Disadvantages • Low enthalpy in phase change • Low thermal conductivity • Flammability

• Subcooling • Corrosion • Phase separation • Low thermal stability

As a main advantage, the amount of energy stored by the PCM during the phase change (latent heat) is much greater than the energy that is gained in comparison with other substances that only operate with sensible heat, being necessary a smaller volume of material storage.

When the heat is extracted, the PCM Solid, which has a low thermal conductivity, freezes on the heat transfer surface causing a significant drop in the heat transfer coefficient. Therefore, the heat exchange area and / or the heat transfer coefficient must be increased.

2.2.4 Maturity

In 2011, Tamme [13] provided the state of maturity of thermal energy storage systems. As can be seen in Figure 2.3.7, technologies with less maturity have the greatest potential to reduce the amount of material needed for storage.

The technology of thermal storage with materials with phase change has a TRL (Technology Readiness Level) between 5 -8. The materials used are inorganic or organic with the function of storing energy in the form of heat during the phase change (usually from solid to liquid, but also from liquid to gas). The heat can be obtained from any conventional and renewable heating system (boilers, Combined Cycle, heat pumps, biomass, solar thermal and photovoltaic solar.) The efficiency of these systems is estimated between 75-90% with applications at the domestic level, commercial and district heating [14].

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2.2.5 National Context

Mexico is one of the 5 countries with the greatest potential in the world in terms of solar energy, its use through thermal storage is capable of providing a series of services to the energy system such as:

Offer better performance and reliability to the system by extending operating hours beyond sunset for CSP plants.

Avoid fluctuations associated with the intermittency of clean energies.

Make better use of surplus energy making plants more efficient.

Thermal storage is one of the key technologies that can support decarbonization.

Use of residual heat in industrial processes

By investing in research and development of demonstration projects, thermal storage costs could be reduced and their development accelerated.

Currently in Mexico and therefore INEEL does not have infrastructure in this area, the only development we have is the use of small thermal storage tanks with thermal oils as backup for parabolic trough solar concentrator technologies.

2.2.6 Challengues

PCM storage can be designed with a favorable temperature gradient (Thermocline) in a storage tank. This allows the design of a single storage tank instead of two, which would allow cost reduction. Increase the available thermal power. Combination of PCMs with heat transfer fluids, in their encapsulation with conductive media. • Creation of carbon based matrix composites • Changes in the design of storage systems that allow an increase in the availability of energy. • Use of nanomaterials

2.3 Guiding Questions

• What is the national context on thermal storage? Solar resource available in Mexico, Concentration technologies used, Applications, Research centers and lines, Demonstration projects. • The PCM, an alternative for the deployment of thermal storage in Mexico? Definition, types, price, advantages and disadvantages, storage systems with PCM degree of maturity, cost-benefit, experimental projects, demonstrations or pilots, Institutions involved applications.

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• What are the priorities and the first steps to achieve the deployment of thermal storage in Mexico? . Definition of priorities, Recommendations of the experts, collaborative projects.

2.4 Figures

Figure 2.3.1 Classification of PCM´s [1]

Figure 2.3.2. Proposal for latent heat storage in cascade with 5 PCM according to Dinter et al. [7]

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Figure 2.3.3. Schematic diagram of the reflux heat transfer storage system (RHTS) [8]

Figure 2.3.4. Prototype storage with NaNO3 and interior fins for better perfomance in heat transfer [9]

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Figure 2.3.5. PCM evaporator module in Carboneras, Spain (14 tons of sodium nitrate, average temperatura=306°C) [11]

Figure 2.3.6. Test installation with PCM based on TES systems for demonstration process (a) is burning test cycle (without isolation) (b) photo of NaNO3 capsules in the testing section. [12]

Figure 2.3.7. Maturiry of storage technologies [13]

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2.3 References

[1] K. P. Kinga Pielichowska, «Phase change materials for thermal energy storage,» Progress in

Materials Science, vol. 65, pp. 67-123, 2014.

[2] T. V. C. C. B. D. Sharma A., «Review on thermal energy storage with phase change materials and

applications,» Renew Sust Energy , vol. 39, pp. 246-257, 2012.

[3] S. W. B. F. Liu M., «Review on storage materials and thermal performance enhancement

techniques for high temperature phase change thermal storage system,» Renew Sust Energy

Rev, vol. 16, pp. 2118-32, 2012.

[4] X. H. Z. Y. Yang R, «Preparation physical property and thermal physical property of phase change

microencapsule slurry and phase change emulsion,» Solar Energy Materials & Solar Cells, pp.

405-416, 2003.

[5] O. A. B. S. Kurklu A, «Thermal performance of a water-phase change material solar colector,»

Renew Energy, vol. 26, pp. 391-9, 2002.

[6] L. M. Hammou ZA, «A hybrid thermal energy storage system for managing simultaneously solar

and electric energy,» Energy Convers Manage, vol. 47, pp. 273-88, 2006.

[7] G. M. T. R. Dinter F., «Thermal energy storage for commercial application (TESCA), a feasibility

study on economic storage system,» de Springer-Verlag, Berlín, Alemania, 1991.

[8] Z. D. E. M. Adinberg R., «Heat transfer efficient thermal energy storage for steam generation,»

Energy conversion and managment, nº 51, pp. 9-15, 2010.

[9] B. T. S. W.-D. L. D. Laing D., «Advanced high temperatura latent heat storage system-desing and

test results,» de The 11 th international conference on thermal energy storage, 2009.

[10] B. C. T. L. D. S. W.-D. Laing D., «Thermal energy storage for direct steam generation,» Solar

Energy, nº 85, pp. 627-33, 2011.

[11] S. Z. M. L. Antje Worner, «Thermal energy Storage Developments in the Department Thermal

Process Techonology,» Institute of engineering Thermodynamics, Alemania, 2016.

[12] B. J. T. K. C. J. N. S. O. A. M. W. Zheng Y., «Experimental and computational study of thermal

energy storage with encapsulated NaNo3 for high temperature applications,» Solar Energy, vol.

115, pp. 180-194, 2015.

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[13] T. R., «Thermal energy storage for industrial applications,» de storage for industrial applications

IEA Workshop , 2011.

[14] BEIS by Delta Energy & Environment Ltd., «Evidence gathering,» Deparment for Business,

Energy & Industrial Strategy, London, UK, 2016.

[15] L. F. Cabeza, Advance in thermal Energy Storage Systems. Methods and Applications, United

Kingdom: Elsevier, 2015.

[16] K. Kayugz, «Experimental and theorical investigation of latent heat,» de Energy Convers

Manage , 1995.

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WORKTABLE 2: THERMAL STORAGE. PANEL A, November 14, 2017. TIMETABLE ACTIVITIES TOPICS GUIDING QUESTIONS FOR PANELISTS

11:45 -12:00 Leader intervention Welcome and introduction

Relevance of Solar Thermal Energy Storage

What is your vision of solar thermal energy storage for industrial applications and for electricity generation?

How solar thermal energy storage influences energy efficiency and emission reduction?

Can thermal storage reduce the intermittency of solar energy?

12:00 - 14:00

Overview of Solar Thermal Energy Storage (All panelists)

14:00 - 15:00 LUNCH

15:00 -15:10 Antonio Diego Marín PhD intervention INEEL

National Context of Solar Thermal Storage

Solar resource in Mexico

Solar concentration technologies used in México

Solar Thermal storage in Mexico

What is the solar resource available in Mexico?

Which solar concentration technologies are used in Mexico?

What are the applications?

What is the market potential?

Which Institutions are involved?

What is the current infrastructure?

Are there solar thermal storage projects in Mexico?

What are the challenges of solar thermal storage in Mexico?

15:10 -15: 30 Manuel I. Peña Cruz PhD presentation CIO

15:30 - 15:50 Ignacio Martín Domínguez PhD presentation CIMAV

15:50 - 16:10 M.C. Juan R. Ramírez Benítez presentation INEEL

16:10 - 16: 30 Fernando Hinojosa Palafox PhD presentation Universidad de Sonora

16:30 – 17:00 Questions to panelist from leader and observers

17:00 -17:30 Initiatives identification R+D+I All participants

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WORKTABLE 2: THERMAL STORAGE. PANEL B, November 15, 2017. TIMETABLE ACTIVITIES TOPICS GUIDING QUESTIONS FOR PANELISTS

09:00 - 09:15 Antonio Diego Marín PhD intervention INEEL

Solar Thermal Storage with Phase Change Materials

(PCM’s)

Solar Thermal Storage with PCM´s

Solar Thermal storage systems with PCM´s

Applications of solar thermal storage with PCM´s to the industry and electric generation

What does solar thermal storage with PCM consist of?

What are the most used PCM´s?

What are its advantages, disadvantages and degree of maturity?

What are the design parameters of a Solar Thermal Storage System with PCM´s?

What are the most used PCM storage system?

What is the cost-benefit of storage system with PCM´s?

What is the methodology for integrating PCM system?

What are its applications to the industry and electric generation?

Are there commercial applications?

What are the challenges in the thermal storage with PCM?

Which institutions are involved?

What is the necessary infrastructure?

09:15 - 09:45 Sudhakar Neti PhD presentation Lehigh University

09:45 - 10:15 Yogi Goswami PhD presentation South Florida University

10:15 - 10:45 Carlos E. Romero PhD presentation Lehigh University

10:45 - 11:00 BREAK

11:00 - 11:30 Hugo Caram PhD presentation Lehigh University

11:30 - 12:00 Questions to the panelist from leader and observers

12:00 - 12: 45 Initiatives identification R+D+I All participants

12:45 – 13:00 BREAK

13:00 - 14:00

Analysis of initiatives R+D+I All participants

Priorities for Mexico in Solar Thermal Energy Storage

Opportunities of R+D+I

Main challenges

What are the priorities that you consider for solar thermal storage in Mexico?

What studies are necessary for the application of solar thermal storage in Mexico?

What Solar thermal storage systems with PCMs will be feasible in Mexico?

14:00 – 15:00 LUNCH

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TIMETABLE ACTIVITIES TOPICS GUIDING QUESTIONS FOR PANELISTS

15:00 - 15:10 Leader intervention Priorities for Mexico in Thermal Storage

Objective and scope

Benefits

Activities in 2, 3 y 4 years

Collaboration opportunities

Need for training of human resources

• What are the key factors for the deployment of solar thermal storage? • Are there linkage opportunities that promote the integration and development of solar thermal storage in Mexico? • What would be the first steps for the use of solar thermal storage in Mexico?

15:10 - 17:00 Analysis of initiatives R+D+I All participants (continue)

17:00 - 17:30 Summary of initiatives All participants

panel 2: thermal storage · 2. thermal storage 2.1 descripción in the framework of energy storage,...

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