Thermal energy storage systems store thermal energy and make it available at a later time for uses such as balancing energy supply and demand or shifting energy use from peak to off-peak hours. The document discusses several types of thermal energy storage including latent heat storage using phase change materials, sensible heat storage using temperature changes in materials, and thermo-chemical storage using chemical reactions. Case studies of thermal energy storage applications in solar plants, buildings, and cold chain transportation are also presented.

1. Thermal Energy Storage
system
By
Abhinav Bhaskar
1

2. Content Layout
Introduction To TESS
Classification
Latent Heat Storage
Phase change materials and application
Case study application
References
2

3. Thermal energy storage –Why do we need it ?
Energy demands vary on daily, weekly and seasonal bases. TES is helpful for balancing
between the supply and demand of energy
Thermal energy storage (TES) is defined as the temporary holding of thermal energy in
the form of hot or cold substances for later utilization.
TES systems deal with the storage of energy by cooling, heating, melting, solidifying or
vaporizing a material and the thermal energy becomes available when the process is
reversed.
TES system for a particular application depends on storage duration, economics, supply
and utilization temperature requirements, storage capacity, heat losses and available
space
Peak Shaving
3

4. Demand Supply mismatch during peak hours
State Demand Supply Surplus/Deficit Percentage
Chandigarh 367 367 0 0.00
Delhi 6006 5925 81 1.35
Haryana 9152 9152 0 0.00
Himachal Pradesh 1422 1422 0 0.00
Jammu and Kashmir 2554 2043 511 20.01
Punjab 11534 10023 1511 13.10
Rajasthan 10642 10642 0 0.00
Uttar Pradesh 15670 13003 2667 17.02
Uttrakhand 1930 1930 0 0.00
4

5. Regional Supply Demand Mismatch-Year 2014
Region
Energy Peak
Requirem
ent
Availabilit
y
Surplus/Def
icit % Demand Met
Surplus/D
eficit %
Northern 332453 311589 20864 6.2757743 51977 47642 4335 8.340227
Western 317637 314923 2714 0.8544345 44166 43145 1021 2.311733
Southern 285797 274316 11481 4.017187 39094 37047 2047 5.236098
Eastern 119082 117155 1927 1.6182127 17040 16932 108 0.633803
North-Eastern 14224 12982 1242 8.731721 2528 2202 326 12.89557
5

6. Thermal Energy storage projects –World Wide
6

7. TES : Thermal Energy Storage
7
0
10
20
30
40
50
60
70
0 5 10 15 20 25
Temperature
Heat added Q
Solid -Solid
Solid-liquid
liquid-vapour
Latent Heat
Latent Heat
B
C
D
E
O
A

8. Process flow in a TES
8
Charging Storing DischargingExcess
Heat/Cold

9. Thermal Energy Storage types
9
Thermal
energy
storage
Cryogenic
heat
storage
Latent heat
storage
Sensible
heat
storage
Thermo-
chemical
heat
storage
Combination of
LHES and SHES

10. Sensible Heat Storage
Thermal energy is stored by raising the temperature of a solid orliquid. SHS
system utilizes the heat capacity and the change in temperature of the material
during the process of charging and discharging.
Amount of heat stored depends on the specific heat of the medium, the
temperature change and the amount of storage material.
Ti = Initial Temperature
Tf= Final Temperature
Q= Heat stored Cp =Specific Heat m= mass of the material
10

11. LHES
11
The earliest Latent Heat energy storage system

12. 12

13. Phase change material-Classification
13
Phase change
materials
Organic
Paraffin compounds
Non-paraffin compounds
Inorganic Salt Hydrates
Metallics
Eutectics
Organic-Organic
Inorganic-Inorganic
Inorganic-organic

14. Selection Criteria for PCM material
Melting temperature
latent and sensible heat capacities
Thermal stability, mechanical stability
Cyclic property degradation
Heat transfer characteristics
Cost
Corrosiveness
Ozone depleting potential
Fire hazard
Ease of encapsulation
14

15. Melting Enthalpy and Temperature of PCM materials
15
Melting temperatures help in
choosing the correct material
for an application

16. Organic PCM materials
Paraffins, fatty acids and sugar alcohols can be used as PCM . These material classes cover the
temperature range between 0 ºC and about 200 ºC.
Due to the covalent bonds in organic materials, most of them are not stable to higher
temperatures.
The most commonly used organic PCM are paraffins. Paraffin is a technical name for an
alkane, but often it is specifically used for linear alkanes with the general formula CnH2n+2
Paraffins show good storage density with respect to mass, and melt and solidify congruently
with little or no subcooling.
Thermal conductivity is comparatively low.
vapor pressure is usually not significant. Their volume increase upon melting is in the order of
10 vol.%; this is similar to that of many inorganic materials, but less critical as paraffins are
softer and therefore build up smaller forces upon expansion.
16

17. Alkanes as PCM materials
17
-Pure Alkanes are
expensive
-Produced from
fractional distillation
of petroleum
-A mixture of alkanes
can be used
-This provides better
flexibility in terms of
temperature ranges
A3
A4

18. Slide 17
A3 Author, 9/2/2015
A4 Tetra Decane is the smallest alkane which has a melting point higher than zero
Author, 9/2/2015

19. Fatty acids as PCM
18
A5

20. Slide 18
A5 Author, 9/2/2015

21. Inorganic Phase change materials
19
Material Melting
Point ©
Density
(kg/m3)
Latent
Heat(kJ/kg)
Heat
stored(kJ/k
g)
Heat
stored(MJ/
m3)
NaNO3 310 2260 172 354 800
KNO3 330 2110 266 388 819
NaOH 318 2100 165 373 783
KOH 380 2044 150 297 607
MgCl2/KCl/
NaCl
380 1800 400 496 893
FeCl2 304 2800 266 336 941
KNO3/4.5%
KCl
320 2100 150 271 569

22. Salt hydrates as PCM material
20

23. Eutectic Mixtures as PCM
21

24. Technical Data for a RT-25 , Rubitherm GMBH
22

25. Commercially Available Phase change material
23

26. Solar thermal-Single tank schematic
24
Source:research.fit.edu/nhc/documents/TES_NAI_Journal_Final.pdf

27. Solar thermal -Two tank molten salt storage
25
Source:research.fit.edu/nhc/documents/TES_NAI_Journal_Final.pdf

28. Transportation-Cold chain
• PCM materials are used for stabilizing temperatures during
transportation of goods
• They have replaced water as the temperature stabilization agent
in medicine transportation. Due to the fact that PCM’s have higher
melting point then water the medicine will not be subjected to
lower temperatures then necessary and the risk of crystallization
in the product has been eliminated.
• PCM can revolutionize the frozen goods transportation market.
• Replaced Dry ice is the most common used freeze agent in this
type of transportations today. It is
26

29. PCM performance in cold chain application
Generic Name Pros (Cold chain application) Cons(Cold chain application)
n-Alkanes: CH3(CH2)nCH3 High latent heat; inert,
non-toxic, non- corrosive
Limited availability,
limited biodegradability
Fatty Acid Methyl Esters:
CH3(CH2)nCOOCH
Biodegradable, non-toxic, non-
corrosive
Limited availability, strong odor,
solvent for EPS, latent heat
below alkanes
Fatty Alcohols:
CH3(CH2)nCH2OH
Biodegradable, non-toxic Limited availability, odor,
flammable, easily oxidized,
latent heat below alkanes
Fatty Acids: CH3(CH2)nCOOH Biodegradable, good cycling
stability, limited super-cooling
Limited availability, causes
burns, corrosive, latent heat
below alkanes
Salt Hydrates
(inorganic): Salt∙nH2O
Water based systems, packaging
compatible, good latent heat
Very limited availability, poor
cycling stability, may be
corrosive
27

30. Green Buildings
28
PCM materials are used for creating temperature
control in Green buildings.
• Commercial projects in Australia and Canada are
showing good performance .
• Encapsulated PCM materials can be mixed with
the building construction material according to the
requirement.
• Lot of research is being done on embedding PCM
material in the glasses used in buildings these days
.
• Both cold and hot climates can benefit from the
use of PCM in building applications .
• Increases the “thermal inertia” of the buildings by
300%.
• Organic PCM materials are being used
commercially.

31. PCM Encapsulation
29
Solid PCM Liquid PCM Solid PCM
Heating Cooling
Shell
thickness

32. Case studies and application
Project Name
Technology
Type
Technology
Type Category 1
Technology
Type Category 2
Rated Power in
kW
Duration at
Rated Power
HH:MM
Status Web Link
India One Solar
Thermal Plant
Heat Thermal
Storage
Heat Thermal
Storage
Thermal
Storage
100016:0.00
Under
Construction
Renewables
Capacity Firming
http://india-one.net
Clique Solar
Solar Thermal
HVAC System
Chilled Water
Thermal
Storage
Chilled Water
Thermal
Storage
Thermal
Storage
17548:0.00 Operational
Electric Bill
Management with
Renewables
http://www.cliquesolar.com/latest.a
spx#
KVK Energy
Solar Project
Molten Salt
Thermal
Storage
Molten Salt
Thermal
Storage
Thermal
Storage
1000004:0.00
Under
Construction
Renewables Energy
Time Shift
http://www.nrel.gov/csp/solarpaces
/project_detail.cfm/projectID=260
Gujarat Solar
One
Molten Salt
Thermal
Storage
Molten Salt
Thermal
Storage
Thermal
Storage
250009:0.00
Under
Construction
Renewables Energy
Time Shift
http://www.nrel.gov/csp/solarpaces
/project_detail.cfm/projectID=263
Diwikar CSP
Plant
Molten Salt
Thermal
Storage
Molten Salt
Thermal
Storage
Thermal
Storage
1000004:0.00
Under
Construction
Renewables Energy
Time Shift
http://www.nrel.gov/csp/solarpaces
/project_detail.cfm/projectID=258
30

33. Major companies in India
TESSOL
CoolElectrica- Promthean Power systems
Cristopia Energy
Clique Solar
Pluss (Research , Development and Manufacturing)
31

34. TESSOL
32
TESSOL Launches PLUGnCHILL Freezebox for grocery e-
commerce
TESSOL has developed a single and dual temperature freezer
box for chilled and frozen transport of food / pharma products
in the last mile. The box that comes in 100-200 liter capacity
can transport goods in a desired temperature range for 6-8
hours while maintaining the desired temperatures. Some key
features of the system:
1. Compressor less system on board (no power connection or
additional load required)
2. Contains chargeable cartridges that can be added and
removed in a couple of minutes
3. Thermal cartridges charged in an outside chiller and inserted
in the vehicle 30 mins before leaving for a delivery
Freezebox Fits inside the delivery
truck

35. Promethean Power Systems
33
Feature Benefits
Cooling Farm
Produce at the
Source
• First cool and then transport principle enables longer
shelf life and higher margins on premium quality
produce.
• Capture more % of farmers in the catchment area.
• Eliminates post harvest losses
Cold storage back
up
• Eliminates Diesel generator sets.
• Low maintenance and operation costs.
• Unlike electro-chemical batteries , thermal batteries
don’t require replacement every 3-5 years.
Simple Flexible
design
• Single phase connection at farms
• Easy to operate.

36. 34
Technical Specifications

37. Challenges with Phase change materials
Material Compatibility
Material Properties and Thermal Performance
Packaging for Use
Conditioning for Use
Cost and Availability
Health, Safety and Disposal
35

38. 36
Comparison of water based and PCM based packaging

39. 37

40. Thermo Chemical Energy Storage (Brief)
38
• Storage by means of chemical
reactions
• Using reversible
endothermic/exothermic
reactions.
• Drawbacks may include
complexity, cyclability,
uncertainties in the
thermodynamic properties of the
reaction components and of the
reaction kinetics under a wide
range of operating conditions,
high cost, toxicity, and
flammability

41. References
http://www.coldchaintech.com/assets/Cold-Chain-Technologies-PCM-White-Paper.pdf
http://www.pluss.co.in/consulting.html
https://beopt.nrel.gov/sites/beopt.nrel.gov/files/Sharma%20et%20al,%202009%20-
%20Review%20on%20thermal%20energy%20storage%20with%20phase%20change.pdf
http://www.tessol.in/wp-content/uploads/2013/03/PLUGnCHILL-Brochure.pdf
http://www.rgees.com/technology.php
For more comprehensive lists of materials the reader should look at the early publications of Steiner et al. 1980, Abhat 1983, Lane 1983 and 1986,
Schröder 1985, and more recent publications like Kakiuchi et al. 1998, Hiebler and Mehling 2001, Zalba et al. 2003, Sharma et al. 2004, Farid et al.
2004, and Kenisarin andMahkamov 2007.
39