1
Review on thermal energy storage using phase change materials and
applications
1
Nagesh.R.Biradar, 2Chetan Appasab Chougale
1
Asst.proff. Department of Mechanical Engg, ICOER PUNE, MH-India,biradarnagesh72@gmail.com
2
Asst.proff. Department of Mechanical Engg, ICOER PUNE, MH-India

energy storage devices which are equal to developing new
Abstract-- Solar energy is a renewable energy source that can
energy sources. The stored energy will be suitable forms
generate electricity, provide hot water, heat and cool a house
which can be conventionally converted into the required
and provide lighting for buildings. In response to increasing
form.
electrical energy costs, thermal storage technology has recently
been developed. This paper presents an introduction to
previous works on thermal energy storage using PCM and
their applications. The choice of the substances used largely
A. Necessity of energy storage:
The need of thermal energy storage may be linked to the
following cases
depends upon the temperature level of the application. Phase
• It may reduce the mismatch between Energy supply and
change material (PCM) are one of the latent heat materials
Energy demand.
having low temperature range and high energy density of
• When intermittent Energy sources are utilized.
melting– solidification compared to the sensible heat storage.
• The compensation of the solar fluctuation in solar heating
Latent heat thermal energy storage (LHTES) with phase
systems.
change materials (PCMs) deserves attention as it provides high
B. Energy storage methods:
energy density and small temperature change interval upon
melting/solidifying. Phase change materials (PCMs) are
becoming more and more attractive for space heating and
cooling in buildings, solar applications, off-peak energy
The
different
methods
of
energy
storage
include
mechanical, electrical and thermal energy.
B.1 Mechanical energy storage:
storage, and heat exchanger improvements. Latent heat
Mechanical energy storage systems include flywheel
thermal energy storage (LHTES) offers a huge opportunity to
storage, Hydraulic accumulator, and compressed air energy
reduce fuel dependency and environmental impact created by
storage. Flywheels are more suitable for intermediate
fossil fuel consumption.
storage while hydraulic accumulator and compressed air
energy storage are used for large scale energy storage.
Index Terms-- Phase Change Material (PCM), renewable
B.2 Electrical Energy storage:
energy, Thermal Energy storage, Latent heat thermal energy
It involves the use of an electric field to store energy.
storage (LHTES), high energy density.
Examples include: superconducting magnetic energy storage
(SMES), Capacitor and super capacitor and batteries.
I. INTRODUCTION
The depletion of fossil fuels and increase in the level of air
pollution are leads to the innovation towards the energy
efficiency and use of renewable energy sources. In most
regions of world solar radiation is considered to be one of
the main sources of the Energy. The scientists all over the
world are in a research of new and more effective use of
renewable energy sources. One of the methods is to develop
B.3 Thermal Energy Storage:
The thermal energy can be stored as Sensible heat storage,
Latent heat storage and thermo chemical storage.
B.3.1 Sensible heat storage:
The storage is based on temperature change in the material.
The sensible heat storage system utilizes the heat capacity
and change in temperature of the material during the process
of charging and discharging.
2
Phase change material is a substance which absorbed or
Table 1. Material for sensible heat storage:
Phase
Medium
Temp
Density
Specific
Rang
Kg/m³
Heat J/kg
[ºC]
Solid
released heat during a phase change from solid to liquid or
liquid to gas or vice versa. The PCM are Latent heat storage
materials.
K
The phase change used for PCMs is the solid-liquid or
Rock
7-27
2560
879
liquid-solid change. Liquid –gas phase change are not
Brick
17-37
1600
840
practical for use as a thermal storage due to their large
Concrete
7-27
2100
880
volume or high pressure required to store the materials when
Sand
7-27
1550
800
they are in gas phase.
Water
7-97
1000
4180
A. Properties of Phase change material:
Engine Oil
Up to
888
1880
The PCMs are to be used in the design of thermal storage
systems should pass desirable thermo physical, Kinetics and
157
Ethanol
Liquid
Up to
790
2400
chemical properties which are as follows.
A.1. Thermal Properties:
77
CalorieaHT43
12-260
867
2200

Suitable Phase -transition temperature.
Butanol
Up to
809
2400

High latent heat of transition.

Good heat transfer.
118
Other Organic
Up to
800
2300
420
Selecting a PCM for a particular application, the
operating temperature of the heating or cooling should
be matched to the transition temperature of the PCM.
B.3.2 Latent heat (Phase change) storage:
The heat energy released or stored based on phase change of
storage material from solid to liquid or liquid to gas or vice
The latent heat should be as high as possible, especially
on a volumetric basis, to minimize the physical size of
the heat store. High thermal conductivity would assist
versa.
the charging and discharging of the energy storage.
B.3.3 Thermo chemical energy storage:
The thermo chemical energy can be released or absorbed
based on breaking or reforming of chemical bonds in a




reversible reaction.
Thermal Energy storage
Chemical
Thermal
A.2. Physical properties:
High density.
Small volume change.
Favorable phase equilibrium.
Low vapor pressure.
Phase stability during freezing melting would help towards
setting heat storage and high density is desirable to allow a
Latent
Heat
Sensible Heat
Liquid
Solids
SolidLiquid
LiquiGaseous
smaller size of storage container. Small volume changes on
phase transformation and small vapor pressure at operating
SolidSolid
Figure 1.Hierarchy of thermal storage of solar energy
II. Phase Change Material (PCM):
temperatures to reduce the containment problem.
A.3. Kinetic properties:


No supercooling.
Sufficient crystallization rate.
3
Supercooling has been a troublesome aspect of PCM
Paraffin
Compounds
development, particularly for salt hydrates. Supercooling of
more than a few degrees will interfere with proper heat
Organic
Non paraffin
compounds
extraction from the store, and 5–100 C supercooling can
prevent it entirely.
Salt Hydrate
A.4. Chemical properties:
 Long term chemical properties.
 Compatibility with materials of construction.
 No toxicity.
 No fire hazard.
Phase change
material
Inorganic
Metallics
Organicorganic
PCM can suffer from degradation by loss of water of
Eutectic
hydration, chemical decomposition or incompatibility with
Inorganicinorganic
materials of construction. PCMs should be non-toxic,
Inorganicorganic
nonflammable and non-explosive for safety.
Figure2. Classification of PCMs
A.5. Economics:
 Abundant.
 Available.
 Cost effective.
B.1. Organic phase change materials:
Low cost and large-scale availability of the phase change
nonparaffins. Organic materials include congruent melting
materials is also very important.
means melt and freeze repeatedly without phase segregation
Organic materials are further described as paraffin and
and consequent degradation of their latent heat of fusion,
B. Classification of Phase change material:
A large number of phase change materials are available in
any required temperature range. The classification of PCMs
is as follows
self nucleation means they crystallize with little or no super
cooling and usually non-corrosiveness.
B.2. Paraffins:
Paraffin wax consists of a mixture of mostly straight chain
n-alkanes CH3–(CH2)–CH3. The crystallization of the
(CH3)- chain release a large amount of latent heat. Both the
melting point and latent heat of fusion increase with chain
length. Paraffin qualifies as heat of fusion storage materials
due to their availability in a large temperature range. Due to
cost consideration, however, only technical grade paraffins
may be used as PCMs in latent heat storage systems.
Paraffin is safe, reliable, predictable, less expensive and
non-corrosive. They are chemically inert and stable below
5000C, show little volume changes on melting and have low
vapor pressure in the Melt form.
4
Table 2. Properties of some paraffin:
Paraffin
Catechol
104.3
207
Acetanilide 222
118.9
222
Freezing
Heat of fusion
point/range (OC)
(kJ/kg)
6106
44
189
P116
45-48
210
Inorganic PCMs are engineered hydrated salt solution made
5853
48-50
189
from natural salts with water. The chemical composition of
6035
58-60
189
salts is varied in the mixture to achieve required phase-
6403
62-64
189
change temperature. Special nucleating agents are added to
6499
66-68
189
the mixture to minimize phase-change salt separation and to
B.4 Inorganic phase change materials:
minimize super cooling, that are otherwise characteristic of
B.3 Nonparaffins:
hydrated salt PCM. Salt Hydrates are characteristic of being
The non-paraffin organic are the most numerous of the
non-toxic, non-flammable and economical.
phase change materials with highly varied properties. Each
of these materials will have its own properties unlike the
B.5. Eutectics:
paraffin’s, which have very similar properties. This is the
largest category of candidate’s materials for phase change
A eutectic is a minimum-melting composition of two or
more components, each of which melts and freeze
storage.
congruently forming a mixture of the component crystals
Table 3. Properties of some non paraffin:
Materials
during crystallization. Eutectic nearly always melts and
Melting
Latent
freezes without segregation since they freeze to an intimate
point(°C)
heat(kJ/kg)
mixture of crystals, leaving little opportunity for the
Formic acid
7.8
247
components to separate. On melting both components
Glycerin
17.9
198.7
liquefy simultaneously, again with separation unlikely.
Methyl Palmitate
29
205
Some segregation PCM compositions have sometimes been
Camphenilone
39
205
incorrectly called eutectics, since they are minimum
Docasyl Bromide
40
201
melting. Because of the components undergoes a peritectic
Caprylone
40
259
reaction during phase transition, however, they should more
Phenol
41
120
properly be termed peritectics.
Cyanamide
44
209
Hydrocinnamicacid
48
118
Camphene
50
238
Nitro Naphthalene
56.7
103
Bee wax
61.8
177
Glyolic acid
63.0
109
Acrylic acid
68.0
115
Phenylacetic acid
76.7
102
Methyl
81
126
Brombrenzoate
5
to deliver hot water the morning after solar collection [10].
In this study [10], the author used 17,5kg of paraffin wax
(m.p. 54°C) in one heat exchanger and water in the other to
Table 4. Phase change Temperature and heat of fusion
of typical commercial PCMs:
PCM
Name
Type of
Product
Astorst
at
HA 17
(
Paraffins
and
waxes)
Astorst
at
HA18
RT26
RT27
Climse
l
C23
Climse
l
C24
STL27
S27
TH29
-
E23
Paraffin
Salt
Hydrate
Meltin
g
point(0
c)
21.722.8
Heat of
fusion(kJ/
kg)
Source
-
Astor wax by
Honeywell(P
CM Thermal
solution)
enable the comparison.
B. Solar air heater:
The problem of solar air heating with systems involving
PCMs has been studied for more than 30 years as evidenced
27.228.3
-
24-26
28
23
232
206
148
24
108
27
213
27
207
Mitsubishi
Chemicals
Cristopia
29
188
TEAP
22-25
-
ZAE Bayrern
by the pioneering work of Morrison, Abdel Khalick, and
Jurinak [14]. The main conclusion of their studies was that
the PCM should be selected on the basis of the melting
point rather than its latent heat and also that systems based
Rubitherm
GmBH
Climator
on sodium sulphate decahydrate as storage medium needs
about one fourth the storage volume of a pebble bed and one
half 5 that of a water tank. Recent research involving hybrid
systems and shape-stabilized phase-change material was
found to yield improved thermal comfort in the winter.
Zhou et al. [13] indicate that 47% normal-and-peak-hour
Salt
Hydrate
Salt
Hydrate
Salt
Hydrate
Mixture
of two
salt
hydrate
Plus
ICE(Mixt
ure of two
non-toxic
Eutectic
solution)
energy savings, and 12% overall energy consumption
reduction were observed.
C.floor and ceiling:
Farid
and
Kong
[11]
constructed
slabs
containing
encapsulated PCMs in spherical nodules. The plastic
spheres contained about 10% empty space to accommodate
23
155
Environmental
Process
System(EPS)
volume expansion. Athienithis and Chen [12] investigated
the transient heat transfer in floor heating systems. Savings
up to 30% were reported. Space
heating systems that
incorporate PCMs located in the ceilings were also
developed.
III. Applications of Phase change Materials (PCMs):
D. Off-peak storage:
A. Solar water heater:-
Latent heat storage systems were proposed to utilize off-
Solar water heater is getting popularity with increasing costs
of energy since they are relatively inexpensive, simple to
fabricate and install, and easy to maintain. To increase the
capacity of systems without ultimately requiring huge
volumes or high temperatures, these systems were designed
with PCMs either located on the bottom, top, or vertical
walls. The PCMs were especially interesting when it came
peak electricity. Using this electricity, PCMs are either
melted or frizzed to store it in the form of latent heat
thermal energy and the heat/coolness is then available when
needed. These systems are generally embedded with active
systems to reduce the peak load and thus eventually
reducing the electricity generation costs by keeping the
demand nearly uniform.
6
applications. The need to save energy is ever increasing and
PCMs might be an important future material class when
E. Indoor walls:
engineers design energy –efficient applications.
The wallboards are suitable for PCM encapsulation. For
instance, paraffin wax, fatty acids, or liquid butyl stearate
impregnated walls can be built by immersion. One of the
V References:
Journal Papers:
interests is the shifting of heating and cooling loads to off-
[1] A.Sharma, V.V. Tyagi, C.R. Chen, D. Buddhi, Review
peak times of electric utility, the other is to reduce peak
on thermal energy storage with phase change materials and
power demand and down size the cooling and heating
applications, Renewable and Sustainable Energy Reviews,
systems. Although much work has been done on
Vol. 13 (2), pp.318-345, 2009.
impregnation techniques, analytical studies, and optimal
melting temperatures, much has to be done to include such
advanced wallboards in actual buildings. Although gypsum
wallboards are naturally considered as they are cheap and
widely used, building blocks and other building materials
impregnated with PCM can be used in constructing a
[2] A. Abhat A. Low temperature latent heat thermal energy
storage: heat storage materials. Solar Energy, vol. 30.
Pp.313-332, 1983. A. Abhat A. Low temperature latent heat
thermal energy storage: heat storage materials. Solar
Energy, vol. 30. pp.313-332, 1983.
building. This could result in a structure with large thermal
[3] H.G. Lorsch, K.W. Kauffman, J.C. Denton, Thermal
inertia without the usual large masses associated with it.
energy storage for heating and air conditioning, Future
energy production system. Heat Mass Transfer Processes,
F. Green houses:
vol. 1, pp.69-85, 1976.
Another application that has a major impact on power
[4] G.A. Lane, D.N. Glew, E.C. Clark, H.E. Rossow, S.W.
demand is the use of PCMs in green houses for storing the
Quigley, and S.S. Drake, “Heat of fusion system for solar
solar energy for curing and drying process and plant
energy storage”, in Workshop on the solar energy storage
production. The format of the conference papers cannot
subsystems for the heating and cooling of building,
allow a survey of the key references on this subject. These
Charlottesville, Virginia, USA, 1975
will be discussed at the conference.
IV. Conclusion:
[5] W.R. Humphries, E.I. Griggs, A designing handbook for
phase change thermal control and energy storage devices,
The storage concept plays a decisive role in use of thermal
systems, especially in areas with a temperature and cold
NASA Technical Paper, p. 1074, 1977
Books:
climate and larger seasonal differences. Phase change
[6] A. George A. Phase change thermal storage materials. In
materials have two favorable properties. They have a very
Hand book of thermal design. Guyer C, Ed., McGraw Hill
high heat storage density and they store and release a
Book Co., 1989
considerable amount of heat at a constant temperature. This
makes PCMs in many applications an interesting alternative
to other heat storage mediums. But in spite of achieved
[7] G.A Lane, Solar heat storage: latent heat materials, vol.
1. USA: CRC Press Inc.; 1983.
improvements there is still potential and need for further
performance enhancement especially in the temperature
range between 5-25, which is crucial for building related
[8] D.J. Morrison, S.I. Abdel Khalik, Effects of phase
change energy storage on the
7
Performance of air-based and liquid-based solar heating
systems. Solar Energy, vol. 20, pp.57-67, 1978.
[9] M.M. Farid, and W.J. Kong, under floor heating with
latent heat storage. In Proc Inst Mech. Eng, vol. 215, pp.
601-609, 2002.