The document discusses thermal energy storage (TES) and its applications in thermal solar power plants. It provides an overview of energy storage, classifications of TES, and how energy is stored in thermal solar power plants using TES. TES allows excess solar energy to be stored and used later for electricity generation. There are economic and energy management benefits to incorporating TES in thermal solar power plants such as reducing costs and improving system stability.

1. Koya University
Faculty of Engineering
Chemical Engineering Department
3rd Stage (2021-2022)
Instructor
Mr. Ahmed A. Maaroof
Prepared by
Safeen Yaseen Jafar
Ibrahim Ali Muhammed
Karzan Nawsherwan Muhammed
Ramazan Shkur Kakl
Submitted Date
5 Dec. 2021
Energy Storage
Heat Transfer Report

2. Table of Contents
Abstract/Summary..............................................................................................................................1
1. Introduction .....................................................................................................................................2
2. Main Body........................................................................................................................................3
2.1 Energy Storage Overview .....................................................................................................................................3
2.2 Why Energy should be stored...............................................................................................................................3
2.3 Thermal Energy Storage (TES)............................................................................................................................4
2.3.1 Why are Thermal Energy Storages Important?.................................................................................................4
2.4 Classification of Thermal Energy Storages (TES)..............................................................................................4
2.5 Thermal Energy Storage in Thermal Solar Power Plant...................................................................................6
2.5.1 Thermal Solar Power Plant Overview ..............................................................................................................6
2.5.2 Types of Solar Thermal Power Plants ..............................................................................................................6
2.5.3 How energy stored in solar thermal power plant? ............................................................................................7
2.5.4 Applications of thermal energy storage ............................................................................................................7
2.5.5 Advantages (Benefits) of thermal energy storage in thermal solar power plants .............................................7
2.5.6 Thermal Energy Storage Market Size by Product Type (2016-2017) ..............................................................8
3. Conclusion........................................................................................................................................9
4. List of References ..........................................................................................................................10

3. LIST OF FIGURES
Figure 1 ............................................................................................................................. 2
Figure 2 ............................................................................................................................. 3
Figure 3 ............................................................................................................................. 3
Figure 4 ............................................................................................................................. 4
Figure 5 ............................................................................................................................. 5
Figure 6 ............................................................................................................................. 6
Figure 7 ............................................................................................................................. 7
Figure 8 ............................................................................................................................. 8
Figure 9 ............................................................................................................................. 8

4. 1
Abstract/Summary
As we know about energy, energy can convert or by other word can change from one form
to another form. So, the sources of energy are large in amounts and maybe some of them cannot
store easily. Because of that problem we need to save our cost and look to important methods by
change the forms of the energy to another to store and make more reliable energy to use. However,
advanced technologies usually used to store the energy and make them along life-time usage. In
this report we will talk about methods to store the energy (by Energy Storage System) benefits of
the energy storages and most important technologies which used. Especially, we will talk about
store of thermal energy by Thermal Energy Storage (TES) in details in this report. Also, their
work and their application in the Thermal Solar Power Plant.

5. 2
1. Introduction
As we know the we have many sources of energy and nowadays we used many equipment
and work hardly in some facility and plant where we use the energies. Some of the energy sources
in that days will always use, because of that they need to store by the new or advanced system of
technologies like Batteries (Chemistry Batteries), Mechanical Storages and thermal energy
storages (energy stored in the form of heat). [1]
If we see previous mid-(50 years ago) years we can see that the first disaster of the petrol
or (oil) in U.S happened and, in this year, several rechargeable batteries created and well-known.
The first energy storage program in 1978 mentioned as “Batteries for Specific Solar
Applications". [2]
Heat is one of the energy forms and it can be transfer like other energy form from one
material to another by difference in temperature. So, in this report we focus on this topic more
than other energy forms. we classified the energy system types into five primary class:
1. Batteries.
2. Thermal.
3. Mechanical Storage.
4. Hydrogen.
5. Pumped Hydropower.
But we focus and discuss the thermal energy more than others. If we ask ourselves about energy
stores in a coffee or tea? Or about ice balls we can think that this energy produced in the form of
the heat (thermal energy form). Solar thermal systems are the most prevalent use for thermal
energy storage. Due to its wide range of benefits. So, the technologies permit us to momentarily
stand-in energy produced to use at a dissimilar time. Consider today's solar thermal power plants,
which generate all of their energy while the sun is shining throughout the day. Excess solar energy
is typically stored in these facilities – in the form of molten salt or other materials – and then used
to produce steam, which powers a turbine to generate electricity later in the evening. [3]
Fig. 1: Energy Storage in real life

6. 3
2. Main Body
2.1 Energy Storage Overview
The development of renewable energies and the necessity. In renewable energy facilities,
energy storage is a critical component. It can reduce power fluctuations, improve system
flexibility, and allow for the storage and dispatching of electricity supplied by renewable energy
sources like wind and solar. Electric power systems employ a variety of storage mechanisms.
Chemical or electrochemical storage, mechanical, electromagnetic, or thermal storage are all
possibilities. A storage medium, a power conversion system, and a balance of plant are the main
components of an energy storage facility. There are numerous different types of batteries for
electrochemical storage, and the majority of them are still undergoing research and development.
[4]
2.2 Why Energy should be stored
Energy should be stored in order to long benefits and reliability and storages are, in the
end, used to enable technology. It has the potential to save customers money while also improving
dependability and resilience, integrating power sources, and reducing environmental
consequences. We can summarize importance of energy storing as below:
• Save Money (operational cost).
• Improve Reliability & Resilience.
• Demand charge
reduction.
• Maximizing
time-of-use
rates.
• Environmental
benefits
(Reduce
Environmental
Impacts).
• Backup Power. [5]
Fig. 2: Stored energy by solar panels
Fig. 3: Importance of storing energies.

7. 4
2.3 Thermal Energy Storage (TES)
(TES) or thermal energy storage is the storage of energy in thermal form and before we
talk about it, we need to define thermal energy. Thermal energy is one form of the energy that can
be transfer between two or more material by difference of their temperatures. So, thermal energy
can be stored via raising or reducing a material's temperature, as new energy technologies are
developed, the word TES is used to describe the temporary storage of high- or low-temperature
energy for later use. A race to develop ways to store extra energy has begun in order to avoid
excess energy from being wasted since the time and location of consumption do not match
production. [6]
2.3.1 Why are Thermal Energy Storages Important?
Thermal energy storage is less complex and expensive than electrical energy storage,
allowing solar thermal power plants to generate electricity regardless of whether the sun is shining.
Because of growing use of TES and more efficient thermal transport networks, the cost of energy
generated by solar thermal power plants technologies has reduced by more than half in the recent
decade. In order to fully utilize TES, solar thermal power plants facilities require heat transfer
components that are both trustworthy and efficient. [7]
2.4 Classification of Thermal Energy Storages (TES)
Energy storages can be classified to two main types:
1. Latent heat energy storage
2. Sensible Heat Storage
Fig. 4: Thermal Energy Storage Tanks

8. 5
3. Thermo-chemical storage
Fig. 5: Thermal Storage Classification
1. Latent heat energy storage
Latent heat storage is one of the thermal storages and the heat emitted or absorbed by a
body during a change of state without a change in temperature, such as from a liquid to a solid or
from a liquid to a gas, is referred to as latent heat. This storage is undergoing a phase change
condition, So, the latent heat storage system is an efficient method of storing thermal energy
because of its high energy density and ability to store heat at a constant temperature matching to
the phase transition temperature of phase change materials.
2. Sensible Heat Storage
Second type of storage of heat storages is that the energy stored through a change in a
material's temperature is known as sensible thermal storage. The heat capacity or a specific heat,
which is the amount of energy required to alter the temperature of one kilogram of a substance
by one degree, is used by the Sensible Heat Storage which can abbreviated by SHS system, as is
the change in temperature of the material throughout the charging or discharging process. The
quantity of heat stored is determined by the medium's specific heat, temperature changes, and the
amount of storage material.
3. Thermo Chemical Energy Storage
Third type here is TCES which mean Thermo Chemical Energy Storage that the energy
received and released in breaking and repairing molecular bonds in a totally reversible chemical
process is crucial to thermochemical systems. The quantity of heat stored in this situation is
determined by the storage medium, the endothermic heat of reaction, and the degree of
conversion. [8]

9. 6
2.5 Thermal Energy Storage in Thermal Solar Power Plant
2.5.1 Thermal Solar Power Plant Overview
Solar thermal power plants are very useful and have many benefits such as reliability and
long life to use which are for electricity generation and they can use (take or draw) energy from
the Sun to heat a fluid to a high temperature. This fluid then transfers its heat to water, which then
becomes superheated steam. This steam is then used to turn turbines in a power plant, and this
mechanical energy is converted into electricity by a generator. [8]
What is the Difference between this plant from Other Plants
This plant different from another plant, also, there doesn't seem like a difference between
coal-fired power stations and hydroelectric plants in terms of how they generate electricity. To
operate a turbine in these ancient power stations, you just need to produce steam. After that, the
generator is connected to the power supply, which converts mechanical power into electrical
power. [9]
2.5.2 Types of Solar Thermal Power Plants
Solar power tower plants, solar dish power plants, and parabolic trough plants are the three
basic means of concentrating solar energy in the CSP producing system.
▪ Solar Power Tower Plants
▪ Solar Dish Power Plants
▪ Parabolic Trough Plants [10]
Fig. 6: Thermal Solar Power Plant

10. 7
2.5.3 How energy stored in solar thermal power plant?
Stored energy can be used in case that renewable energy sources are unavailable, the stored
energy can be utilized. The working principle of a heliostat-type concentrated solar thermal power
plant with a TES is shown in the diagram (Fig. 6). The TES unit, which works as a surplus energy
storage medium, is located between the solar receiver and the turbine. Cloudy weather
circumstances can produce temporary fluctuations in solar energy supply, which the system can
compensate for. It may also adjust power generation from peak solar irradiance to peak electricity
demand hours. The system assists in the development and simple uptake of renewable energy
sources by assuring a continuous power supply to customers. [11]
Fig. 7: Simple PFD of Thermal energy storage (TES) in solar thermal power plant
2.5.4 Applications of Thermal Energy Storage
• Thermal mass would be used in homes to lessen daily temperature changes by retaining
heat throughout the day and releasing it at nighttime, or by chilling the inside of the home
every night to lower the daytime maximum temperature.
• Thermal mass is especially useful in climates where the temperature difference between
day and night is significant.
• Excess electricity is used to make ice for a day of cool, which is a form of daily heat
storage employed in a number of areas, including Japan. [12]
2.5.5 Advantages (Benefits) of thermal energy storage in thermal solar power plants
Today’s thermal energy storage technologies and systems provide a major opportunity for
better economic benefits and enhanced energy management of existing and planned energy
assets and infrastructure. This covers any expected mismatches in both supply and demand for
heating or cooling requirements thereby offsetting differences in time and magnitude of heat or
cooling production.

11. 8
Fig. 8: TES have many benefits such as two above benefits.
• Economic Benefits: By constructing systems to satisfy average demand rather than simply
peak and cycling demand, thermal energy storages deliver substantial economic benefits
by lowering total capital expenditures as well as operations and maintenance expenses of
heating and cooling. Thermal energy storages can help with demand side management and
capacity expansion, as well as lowering life cycle costs and levelized cost of energy, and
maybe advancing time of use pricing and billing.
• Energy management Another significant emphasis area where Thermal energy storages
may assist enhance overall system stability, performance, and demand responsiveness is
energy management, which involves smoothing out any possible supply and demand
imbalances as well as system temperature changes. It can also increase the heating's
dependability, availability, operability, and maintainability. [13]
2.5.6 Thermal Energy Storage Market Size by Product Type (2016-2017)
Fig. 9: Above data chart shows you the increase of the size of growing of TES.
The market in the United States is predicted to grow significantly in the next years as a
result of the growing number of thermal energy storage projects across the country. In 2018, the
United States, for example, accounted for 33% of the 18 projects now in development and 41%
of the total 1,361 operational programs worldwide. The presence of important industry players in
the country is expected to accelerate the growth of the TES market in the United States. [14]

12. 9
3. Conclusion
As we talked about, we need to save our energy and store it even it in any form like
chemical, electrical, especially thermal energy. So, for thermal energy we have some types of
storages as we mentioned in this report in previous sections. Finally, we can summarize our report
in some following points as well as below:
✓ There are many energies form not only thermal and electrical or chemical energy.
✓ All of energy must be stored.
✓ Storing energy have many techniques or methods.
✓ We have more than one type of storages of energy.
✓ Some form of energy needs special storage.
✓ Thermal energy storages (TES) can be used in thermal solar power plant and it have many
important benefits as we mentioned in this report.
✓ TES important for economic benefits and energy management.

13. 10
4. List of References
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Germany: Springer. [eBook] Available at:
https://books.google.iq/books?id=ApGyDwAAQBAJ&printsec=frontcover&hl=ar&source=g
bs_ge_summary_r&cad=0#v=onepage&q&f=false [Accessed 2 Dec. 2021].
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https://www.sandia.gov/ess-ssl/energy-storage-systems-history/. [Accessed 2 Dec. 2021].
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https://www.sciencedirect.com/book/9780080994246/future-energy [Accessed 2 Dec. 2021]
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storage in renewable energy systems. International Journal of Hydrogen Energy, 41(45),
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Nov. 2021].
5. Facilitiesnet. (2016). Five Benefits of Energy Storage: The Holy Grail of Energy. [online]
Available at: https://www.facilitiesnet.com/energyefficiency/article/Five-Benefits-of-Energy-
Storage-The-Holy-Grail-of-Energy--16907. [Accessed 30 Nov. 2021].
6. Celsius Initiative. (2020). Thermal Energy Storage - Overview and basic principles. [online]
Available at: https://celsiuscity.eu/thermal-energy-storage/. [Accessed 2 Dec. 2021]
7. Energy.gov. (2021). Solar Thermal Energy Storage and Heat Transfer Media. [online]
Available at: https://www.energy.gov/eere/solar/solar-thermal-energy-storage-and-heat-
transfer-media. [Accessed 2 Dec. 2021]
8. Energyeducation.ca. (2018). Solar thermal power plant - Energy Education. [online]
Available at: https://energyeducation.ca/encyclopedia/Solar_thermal_power_plant.
[Accessed 2 Dec. 2021].
9. HeiSolar. (2020). Solar Thermal Power Plant: Advantages and Disadvantages. [online]
Available at: https://www.heisolar.com/solar-thermal-power-plant-advantages-and-
disadvantages/. [Accessed 4 Dec. 2021].
10. Sawrey, G. (2021). Solar Thermal Power Plants: Pros and Cons. [online] Ecavo. Available
at: https://ecavo.com/solar-thermal-power-plants-pros-and-cons/#types-of-solar-thermal-
power-plants [Accessed 2 Dec. 2021].
11. Alnaimat, F. and Rashid, Y. (2019). Thermal Energy Storage in Solar Power Plants: A
Review of the Materials, Associated Limitations, and Proposed Solutions. Energies, 12(21),
p.4164. Available at: https://doi.org/10.3390/en12214164 [Accessed 30 Nov 2021].

14. 11
12. Ali, S. and Deshmukh, S.P. (2020). An overview: Applications of thermal energy storage
using phase change materials. Materials Today: Proceedings. Available at:
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https://www.resource-innovations.com/resources/benefits-thermal-energy-storage [Accessed
2 Dec. 2021].
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2020-2027. [online] Available at: https://www.grandviewresearch.com/industry-
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