Phase Change Materials in Building Design

This assignment delves into the application of phase change materials (PCMs) within the realm of building design. It examines how PCMs can contribute to enhanced energy efficiency by regulating indoor temperatures, reducing reliance on heating and cooling systems, and mitigating peak energy demands. The document analyzes various PCM types, their integration into building structures, and their impact on overall thermal performance. It also explores case studies and real-world examples demonstrating the effectiveness of PCMs in achieving sustainable building practices.

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COLLABORATION OF PHASE CHANGE MATERIAL AND GREEN ROOFTOP

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Contents
COLLABORATION OF PHASE CHANGE MATERIAL AND GREEN ROOFTOP......5
INTRODUCTION...............................................................................................................5
Green Rooftop.............................................................................................................................8
PCM with Green Rooftop System...............................................................................................8
LITERATURE REVIEW.....................................................................................................9
Latent Heat Storage.....................................................................................................................9
Critical Properties of Material...................................................................................................11
Thermophysical Properties........................................................................................11
Kinetic Properties......................................................................................................12
Chemical Properties...................................................................................................12
Phase Change Material Classification.......................................................................................13
Inorganic....................................................................................................................13
Organic.......................................................................................................................14
Eutectic......................................................................................................................14
Strategies of PCM..............................................................................................................15
Direct Integration.......................................................................................................................15
Immersion..................................................................................................................................15
Encapsulation.............................................................................................................................16
Applications of PCM as Green Rooftop....................................................................................18
BIO-PCM INTEGRATION WITH BUILDING ENVELOPE ACCORDING TO
AUSTRALIAN BUILDING PRACTICES...............................................................................20
Reduction in GHG & Grid Energy............................................................................21
KEY PARAMETERS OF GREENERY SYSTEM FOR BUILDING ENVIRONMENTAL
PERFORMANCE OPTIMIZATION........................................................................................22

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Integration with 3D Model Design............................................................................22
Changed Climatic Conditions....................................................................................23
PROPERTIES OF PCM AND GREENERY SYSTEM CONTRIBUTING TO ENERGY
BALANCE ANALYSIS BY INFLUENCING CONVECTIVE AND EVAPORATIVE HEAT
FLUX.........................................................................................................................................23
NET POSSITIVE AND UNQUALIFIED ECOLOGICAL AND ENVIRONMENTAL
IMPACTS OF PCM AND GREENERY SYSTEM – CONTENDING WITH URBAN
CLIMATE CHANGE................................................................................................................24
MODELLING PCM INTEGRATED BUILDINGS.................................................................25
PCM with Roof and Wall System..............................................................................25
METHODOLOGY............................................................................................................37
PCM with Green Rooftop System.............................................................................................37
Simulation..................................................................................................................................38
REFERENCES..................................................................................................................40

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COLLABORATION OF PHASE CHANGE MATERIAL AND GREEN ROOFTOP
INTRODUCTION
The present world has been experiencing change of climate so rapidly,
depletion of natural resources and run out of the fossil fuels and this process is so
rapid and destructing the environment rapidly. Having experiencing the issue, by
the people and so government starts getting heat to initiate the remedial actions.
The concerns of sustainability of the lives of the people, through sustainability of
the environment have become heat up the entire world, enabling the people to
participate. Sustainable design, in the field of architecture is considered as the issue
so far and so opportunity, as a game changer, from the last few decades. The key
point here is to reduce the costs of energy and unnecessary usage of the material
(Dobbelsteen, 2011). According to experts of the industry, ‘smart and Bioclimatic
Design’ is seen as a potential strategy towards resolving these problems, for
leading better and sustainable built environment. 0
The strategy of Smart and Bioclimatic Design is considered as a concept of
‘approach of the design that deploys the local characteristics, into the urban areas
and buildings’ sustainable design, intelligently.
The report is started with the primary working principles related to the Phase
Change Materials, followed by their critical material properties and different ways
of integrating them, into the structures and buildings. Then the applications of the
PCM are discussed in the industry of building. The concept then begins from a
historical overview and then slowly moves towards the current developments,
commercial products of PCM existing in the market and some of the examples are
mentioned, where the materials of PCM are applied. Accordingly, the kinds of

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applications of the PCM are discussed. Finally, proposals are developed for the
designs, for the PCM integration, in the specified design.
Thermal Energy Storage
Thermal Energy Storage is going to be the primary key technologies, going
to tbe used for the stage of the energy, in the future. There are different kinds of
TES, like latent heat TES that makes use of the latent heat for the process of the
phase change and sensible heat TES that stores heat in the form of solid or fluid in
various thermoelectric devices, photochemical reactions, chemical energy and
various concentrations, etc. Large amount so heats can be stored and released so
rapidly with the TES, as the heat by the solar energy are intermittent sources of
heat. Hence, it stands as an appropriate method for correction of the gap exists in
between the energy demand and supply. Recently, the research of PCMs is
conducted with various melting temperatures.
Thermal energy can be stored in larger amounts, in PCM, because of the
ability to store in larger amounts of thermal energy, as the latest heat storage is
made use. Storage of energy is done in several ways, such as thermally,
mechanically or electrically. There are two forms, within the thermal energy, called
sensible heat storage and latest heat storage, as shown in the figure 2. Heat is
stored by the sensible heat storage materials, through raise of their temperature
(Sharma et al., 2009). Sensible heat storage can be compared with the metal skin
used for the car, which gets heated up, when stayed long in the sun. However, raise
of temperature is also done in the case of the thick concrete wall, which stores the
heat, though it is hardly noticed, as it has higher thermal mass. The property that
determines the amount of energy that it can store is considered as the material’s
specific heat, total change of temperature in the surrounding and the mass
(Pasupathy et al., 2008). However, as opposed to that, latest heat storage is
occurred, with no considerable temperature of the material that stores the heat. The

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logic here is the release or absorption of heat, when the material undergoes change
of phase, from liquid to gas, solid to liquid and vice versa. Such heat storage form,
storage of the heat and release is occurred by the material’s chemical bonds
(Buddhi et al., 2007).
Containment and Integration
The important concern is that, when the phase change materials are found to
be useful with appropriate melting point and other relevant useful properties, how
these materials can be used for the integration in the buildings. There are certain
systems existing, where phase change material stores heat from the sources of cold
or hot that are made by human (Pasupathy et al., 2008), however, the focus of this
report is on the direct applications, integration of phase change material is done in
the component of building, as a green roof top and releases or stores the heat of it,
under climatic conditions direct influence, such as ambient temperature, sun, etc.
PCM as Green Rooftop
The phase change materials applications in green building have been rapidly
and dynamically increasing. These applications are various models of
development. A recent activities of research and development related to the phase
change material technology is discussed, in building applications, in the report.
Models of PCM in buildings are discussed and reviewed, based on the roof and
also as wall and floor and the respective cooling system.
Commercial Products of PCM
Though, there are total 45 PCM products that are available commercially,
only a few of these products are apt for using as the green rooftop and in the
building industry, as they have the melting point temperature, close to the room
temperature (Zalba et al., 2003). Recently, some of the PCM products entered into
the market that makes the PCM applications, more obvious and apt for the clients

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and architects. The main producers of the phase change materials are DuPont and
BASF.
Green Rooftop
A green roof simply or green rooftop is a building roof that is either
completely or partially covered with planted, growing medium or vegetation over a
membrane of waterproofing. Generally, additional layers are required, like
drainage, root barrier and irrigation system.
Green rooftops are made with many purposes, like providing insulation,
absorbing rainwater, increasing benevolence, creating wildlife habitat and
decreasing people’s stress. It provides pleasing and aesthetical landscape, mitigate
the effect of heat island and lower the air temperature in the urban areas. Green
rooftops are of two kinds called intensive roofs and extensive roofs. The first one is
the intensive roofs that are set with the at least 12.8 cm thickness and it provides
better support of various plants and need more maintenance. The second one is the
extensive roofs that is shallow and has the depth of minimum of 2 cm to 12.7 cm,
but has lesser weight compared to the intensive green roof and needs only and
demands very less maintenance.
PCM with Green Rooftop System
It has been studied and analysed that the phase change material can be used
for dual purpose. The first one is for the conservation of energy that would
decrease the emission of the greenhouse gases and the second purpose is that it can
be used for minimizing the usage of the fossil fuels that are going to be diminished
soon, if excessively used. So, thermal storage system based on both phase
changing material as well as traditional concrete system can be tested with the
simulation.

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LITERATURE REVIEW
Latent Heat Storage
Sustainability energy production is not only the problem, but also the storage
of energy. When the storage of the cold and storage are stored, in better amount
within the buildings, it could lower the peak loads that in turn lower the energy
demand (Kundhair et al., 2004). Phase change materials are able to store the energy
in larger amounts, per unit that makes the material, an option interesting for the
usage in the industry of building. Comparison of PCM heat storage versus the
concrete heat storage is shown in the figure 1. Usually, concrete storage is
considered as a thermal mass.
Phase Change Materials have the ability to store the heat both latently, while
undergoing phase change from certain stable to another stable stage and sensibly,
when they exist in solid, liquid or gas state, as shown in Figure 1.

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Figure 1: Phase Change Temperature and Sensible Vs. Latent Heat Storage
It indicates the fact that, if this kind of material, with temperature of either
solidifying or melting is applied, in a facade element, solar heat can be easily
absorbed by this material, without the room gets warmed, behind it. Hence, Phase
Change Material is considered as ‘artificial thermal mass’ material (Fraser, 2009),
as they have the ability to reach the same capacity of heat and effect of heat
buffering, as for example, a thick concrete wall can, however, is done with a
thinner material layer. Producers of commercial PCM products claim many things,
for the products of PCM, for example that a gypsum board layer of 15 mm that
contains phase change material would be equivalent to a concrete wall of 140 mm
width (BASF, 2008), as shown in Figure 1. Though such claims cannot be
scientifically substantiated, it should be made clear that the phase change material

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have the ability to store much better volume of heat per unit volume, when
compared to the materials that can store sensible heat.
Critical Properties of Material
As specified by Buddhi et al., (2007), phase change materials have a fair list
of critical properties, such as chemical, kinetic and thermo physical properties.
Here, other important aspect of this material is, availability and cost of them. The
critical and significant parameters, in this context are the ability of storage of
amount of energy, such as thermal capacity and phase change latent heat of it
(Lassen, 2011). Here, another important property to consider is the melting
temperature. According to many researchers, this melting temperature has to be
above 1 to 3 degrees, from the room temperature desired, for the target is to make
use of the phase change material, for the purpose of desired heat (Peippo et al.,
1991). The following list shows the critical phase change material properties.
Thermophysical Properties
a. High fusion latent heat per unit volume, as the necessary container
volume, for storing the specific energy would be less
b. Melting temperature to be in the range of desired operating
temperature
c. More specific heat, towards providing additional significant and
additional storage of sensible heat
d. More thermal conductivity, for both the phases of liquid and solid,
towards assisting the storage system energy charging and discharging
e. Minor change of volume on phase transformation and minor vapour
pressure at the operating temperature, towards the containment
problem reduction
f. Phase change material congruent melting, towards a constant material
storage capacity, with each of cycle of melting or freezing

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Kinetic Properties
a. Higher rate of nucleation, towards avoiding liquid phase super
cooling
b. Higher crystal growth rate, towards, meeting the demand for
heating the storage system
Chemical Properties
a. Melt or freeze cycle that can be reversible completely
b. No point of degradation, even after numerous melt or freeze
cycles
c. No point of corrosiveness, to the materials of construction
d. Non-flammable, non-toxic and non-explosive materials,
towards better safety
(Buddhi et al., 2007)

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Phase Change Material Classification
Figure 2: PCM Classification
Phase change materials are made of different kinds of materials.
Classification can be done as three types (Sharma et al., 2009), as eutectic,
inorganic and organic. All these three kinds of materials have the similar properties
are so applicable in the building industry, more or less.
Inorganic
Among the three kinds, inorganic category is an important part of the phase
change material, since it consists of metallic and salt hydrates. Here, salt hydrates
are considered to be significant and primary category of the PCM, since they are
available at lower cost and inflammable, which is not the case with the organic
kinds of the PCM. There are also certain other important properties of the
inorganic PCM, such as lower change of volume in between the phases, higher
latent heat per unit and higher thermal conductivity relatively. However, there are
certain disadvantages with the salt hydrates, such as ‘phase segregation’ and

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‘supercooling’, which in terms mean that the material have their function for only
limited phase changes and lose their capacity of heat change gradually. Hence, it is
called ‘limited utility PCM’, for this category of materials (Pasupathy et al., 2008).
Organic
The other kind of material is the organic PCM that has the major category of
fatty acids and parrafins. Initially, their applications were less focused, because of
their inherent risky property of flammability, which is too high, to have its
applications in the components of buildings. Though there is a possibility to
overcome this problem, they also suffer from other drawback that they possess
lower capacity of heat, compared to the salt hydrates and these are available with
expensive price (Kundhair et al., 2004). However, researches on these material
made the researchers to realize that there are certain strong advantages of them,
like chemical stability, adjustable transition zone, good thermal behaviour along
with the physical stability.
Eutectic
Eutectic PCM are the third kind of material, which are made from the
composites of several materials and they can be produced with the aim of
improving the individual products quality, majorly the melting temperature
adjustment and flammability reduction (Zhang et al., 2007). It is important,
especially, while the integration of the PCM is done in the buildings.

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Figure: PCM Integration and Effects Topology (Zang et al., 2007)
An overview of most useful and possible PCM applications in the
components of building is shown in the Figure 6.
Strategies of PCM
The containment of the phase change materials has three basic strategies
basically, in these components of building, as the following (Zhang et al., 2007).
Direct Integration
This is the most economical and simple method, where phase change
materials gets mixed in with the material of building and most often concrete or
gypsum are used (Zhang et al., 2007 and Kundhair et al., 2004).
Immersion
Immersion refers that the porous material gets bathed in the phase change
material fluid, where absorption is done because of the action of capillary. This
method has an advantage that it allows ordinary materials of the building to be
changed into the containers of the phase change material, when needed. Bricks,
gypsum board and concrete blocks are the material used for this purpose. However,
there are certain problems with these methods. Some of the phase change materials
may result in the surrounding constructive material or sometimes end up leaking

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out, when continued to use in the long run. Other associated problem is that the
phase change material heat transfer gets decreased, when used in longer run.
Encapsulation
The problems and challenges associated with the immersion method enabled
to explore and develop the methods of encapsulation. There are two kinds of
encapsulation used, such as macro and micro encapsulation. Macro encapsulation
method makes use of some form of package, like pouches, panels, tubes, spheres
and other receptacles. The purpose of adding these containers is to function as heat
exchangers directly or they can also be incorporated in the products of buildings.
However, there is a problem with the method, called phase separation. It
tends the phase change material to solidify around the edges that decrease the
thermal conductivity, when used for longer time. Another challenge with this
method is that the protection of the macro-capsules is to be done against the
damage, when the building is used, such for the purpose of instance against drilling
done in the walls (Schoosig et al., 2005).
The challenges occurred in the macro encapsulation can be resolved with the
usage of the micro encapsulation, where, enclosing of the spherical, small or rod-
shaped particles is done in polymeric film that has a high and thin molecular
weight. It has very smaller volumes and so prevents the above problem. Most of
the phase change materials with micro encapsulation can undergo for more than
phase transition cycles of 10,000 and so makes the life span of the product to last
for very longer period, of 30 years (Isa et al., 2010). In terms of working of phase
change material and preventing the incorporating the other methods, micro
encapsulation can be considered to be effective. According to researchers, other
drawback is the increase micro-encapsulated phase change material cost (Zalba et
al., 2003). However, other researchers express their opinion that these micro-

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capsules can be well incorporated economically and simply, into the materials of
construction.
An important and last property that can be questioned for micro
encapsulated phase change material is that if it is recyclable or cradle-to-cradle, at
its end of the life time (Lassen, 2011).
Figure 3: Micro-Encapsulated Microscopic Picture

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Figure 4: Lightweight wall Schematic View with PCM Plasterboard with
Micro-Encapsulation
Applications of PCM as Green Rooftop
Having addressing the phase change material working principle, its manners
of integration into the components and buildings and various kinds of them, the
focus is now moved to the phase change material that are available commercially
and over some green rooftop applications.
The first attempt of documentation is done by Maria Telkes, a Hungarian-
American Scientist and Inventory, to use the phase change materials in the
buildings, in the year 1948, in Dover, in the US. Accumulation of solar energy was
done with the use of total 18 solar collectors made of absorber plates that are gauge
and galvanized, covered after black painting, by glazing panels of 1.2 x 3.0 m. The
generated heat, from the solar panels got passed via a fan, through a duct, to 3 bins
of heat storage and these are situated on both the sides of the rooms. The bins for
heat storage consisted of total five gallon drums that got filled Glaber’s Salt or

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sodium sulphate decahydrate. The entire system had the capacity of 11 GJ of
potential heat storage, which was good enough for storing equal energy sufficient
for 12 days of load for heating, for the applications, used in between the melting
point, 32 0 C and room temperature. The operation of the system was successful
and continued for two years, providing 210C, which is a comfortable temperature,
having no need for back-up heating system, secondarily. But, finally, the
experiment was failed, because of the salt decomposition. It would be an example
for left-middle option, in the Figure 5.
There are some on-off experiments, apart from this house, in interest of the
phase change materials, for latent heat storage, and returned really, after oil crisis
in 1970s. There were some researches for the PCM applications in the Trombe
walls and the research is continued over various encapsulation, materials and
respective performance. However, there is no real take-off point, for the sun panel
integration on the buildings. Though the phase change materials have technically
feasible applications to use as green rooftop and solar panels, it still has to be
conventional technology.
Later, most extensive research was done on the phase change material effect
in the components of building and was done by Schossig et al. (2005), performing
experiments and simulations, for 5 years, in full-scale rooms, at the institute of
German Fraunhofer. The research is done on micro-encapsulated phase change
material, integrated in the panels of interior wall. They discovered that the
temperature was exceeded hardly, at 260C, with the melting point temperature,
ranging from 24 0 C to 270C and it decreased the need for the devices of
mechanical cooling increased thermal comfort. There are two things important,
towards its proper functioning. The first one is that dimension of the phase change
materials is done based on the devices of existing shading and expected loads and

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secondly, to ensure that the heat stored in it can be discharged, with adequate
ventilation, during the night (Schossig et al., 2005).
Figure 5: Test Result Comparison with Reference Wall with micro-
encapsulated PCM having 24 to 26 degree Melting Point
BIO-PCM INTEGRATION WITH BUILDING ENVELOPE ACCORDING TO
AUSTRALIAN BUILDING PRACTICES
Bio-PCM is integrated with the building envelope, for its effective benefit
and usage. The integration is done with encapsulation in the flame retardant. It then
would be fit throughout external part of the framing studs, door frames and wall
sockets. When the interior is considered, it is directly placed, behind the
plasterboard. One of the methods used for effective and instant gain of savings
energy is the attic installation, which is simple, for easier and creative integration.
The integration is most is done with the temporary structures and retrofit buildings
also with flexibility.

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Bio-Pcm mats are placed in between the roof trusses or ceiling joists, right
over the plaster ceiling, then the insulation is replaced at the bio-PCM top. There
would dramatic energy savings, as the ceiling would be dynamic thermally, for the
buildings. Steel buildings are used in place of re-roof=baton, in the place of the
existing roof, insulation is done by placing the BioPCM mats, on the roof that is
existing and it would be re-roofed over the upper part. It produces a great savings
of energy, since there is a little thermal mass with the steel buildings. Mats of
BioPCM are to be installed as part of refurbishment or remodeling, while opening
of the ceiling and wall are done. BioPCM is designed and developed to install
along with the necessary insulation.
Most often Bio-PCM integration is preferred to integrate with the ceiling, so
that thermal energy saving is done, during the Sun.
Reduction in GHG & Grid Energy
Usage of the Bio-PCM reduces the usage of the grid energy and greenhouse
gas emission, having the following benefits.
1. Reduction of fluctuation of indoor temperature
2. Reduction of the need for both cooling as well as heating
3. Safety improvement
4. Fire risks reduction
5. Reduction of the overall usage of the energy
6. Grid energy saving, as the energy usage gets shifted away
from the peak demand
These products can be made of plants and last longer for more than 80 years.
And they can also be made with the waste products that get generated and released
from the process of food manufacturing and can be extracted from acidic fatty

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esters compounds that have no nutritional value and very acidic for the purpose of
consumption.
KEY PARAMETERS OF GREENERY SYSTEM FOR BUILDING ENVIRONMENTAL
PERFORMANCE OPTIMIZATION
Bio-PCM is integrated with the building envelope, for the advantages of bio-
degradable benefit, since it is made of natural materials of plant, neutral carbon
footprint, since it off-sets embedded energy as it allows reduction of cooling and
heating, basically. Bio-PCM is 40 times better and efficient, compared to the
traditional thermal mass. It emits lesser than 20 kg of CO2, for usage of one tone,
of equivalent production of thermal mass, whereas concrete produces 150 kg of
CO2.
Latent heat is an important aspect that gets absorbed or released in a system
of thermodynamics, in the process of constant temperature. Phase transition is one
of the examples, like water boiling or ice melting. BioPCM extension is more
compared to water, when it is in solid state.
Most of the BioPCM are built with the fire suppressants, to enact as a shield
to the most small fires extinguishing, adding extra minutes that is critical for
allowing to escape of the occupants, before larger fires are cought. So, it reduces
smoke index of fires. The building structures built in Australia, prefer the standards
of ASTM to be fulfilled, which is a widely trusted source, for technical standards
of systems, products, services and materials. ASTM is an international standards
that guide the manufacturing and design and trade in world economy.
Integration with 3D Model Design
E+ modeling helps testing and simulating both the physical and thermal
properties, like specific heat, density, thermal conductivity, thermal building
material remittance thickness, solar reflectance is conducted by ASHRAE

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(American Society of Heating Refrigeration and Air-Conditioning Engineers. It
makes use of algorithm of finite difference heat balance.
Bio-PCM can be integrated with the structure of the building, along with the
roof and wall insulation. And the three dimensional design can be virtually, created
for commercial box stores, modular homes, offices, schools, synagogues, churches,
agricultural industry, remote telecommunication enclosures, military facilities,
thermal transport, unconditioned light industrial space, warehouse space,
traditional homes and restaurants.
Changed Climatic Conditions
Changed climatic conditions seriously affect the breathing air quality for the
people, dwelling on the earth. Eventually, pure oxygen becomes impure,
combining with carbon dioxide and carbon monoxide, which is widely releasing in
the urban areas. The changed climatic conditions and its affects can be strategically
controlled to flow within the four walls of a house and the thermal stability can be
increased with the use of Bio-PCM, as an insulation material.
PROPERTIES OF PCM AND GREENERY SYSTEM CONTRIBUTING TO ENERGY
BALANCE ANALYSIS BY INFLUENCING CONVECTIVE AND EVAPORATIVE HEAT
FLUX
Bio-PCM, when integrated with the building structures, absorbs heat, for the
entire day and the heat is released back during the nightly. It enables the energy
cycle to run passively for the efficiency of energy, continuously for 24 hours.
Eventually, it makes use of less kWh, for cooling and heating.
The important property of the phase change material is latent heat and
evaporative heat flux. Latent heat can be defined as the total energy needed

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towards change of matter to another state from one state. When considered in the
passive system, the natural heat entering the environment of the building and when
active system is considered, cooling and heating comes from solar PV system or
mechanical system, to collect free energy required for Bio-PCM, to push or pull,
when required and enables to use and function as a thermal battery. So, it
influences and makes use of the evaporative and convective heat flux for energy
balancing. So, it complements the insulation. Hence, it contributes to the greenery
system, since it makes no use of the expensive and high energy usage air-
conditioning system and the Bio-PCMs can be made from the plants, without
making use of the limited metal and material resources.
The Bio-PCM lasts longer than the regular air-conditioning and insulation
methods, used typically, as it can last for life simulation, for 87 years.
NET POSSITIVE AND UNQUALIFIED ECOLOGICAL AND ENVIRONMENTAL
IMPACTS OF PCM AND GREENERY SYSTEM – CONTENDING WITH URBAN
CLIMATE CHANGE
It is the present and advanced thermal stability system that can be most
adoptable and useful, especially, in the urban areas, since the climate change and
suffocation of the breather is more in the urban areas, because of the closed and
large structures that block the air, wherever it is and obstruct its free flow.
Phase change materials have lower embodied energy compared to that of the
brick used commonly. PCM is not made in Australia, so has to be travelled from
long to reach Australia, adding transport and other expenses, increasing pollution
for additional transport. PCM demands installation of wall to use.
Though some of the PCM resist to the fire, some of these materials have
increased fire risk, since they are made of toxic material. Some of them are also

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flame spread, potential for explosion and smoke, when they are held in liability and
containers. So, these kinds of material should not be used for regularly occupied
buildings, because of negative environmental risk.
The net positive environmental impact of the PCM is hence, to decrease the
emission of the greenhouse gases and reduce the consumption of energy, which is
of 40% from building sector, in the world. Changed climatic conditions can be
relieved from the pollution and global warming with the latent heat method with
the PCM applications.
MODELLING PCM INTEGRATED BUILDINGS
PCM is integrated with the system of TES and reduces two problems that are
existing. The first problem is to design and develop the green rooftop to reduce the
global warming impact and decrease the fossil fuels use. A crucial role is played by
the TES, in various applications to make the green rooftop with the phase change
material. When the PCM is used with the TEX, it can enhance the comfort of the
human, as it can decrease the frequency of fluctuation of internal air temperature.
So, temperature of the indoor air would be close the temperature desired and lasts
for longer period. The literature available shows many promising developments
that can be implemented with the PCM material and TES technologies.
PCM with Roof and Wall System
PCM as a Middle Layer
The PCM incorporation is evaluated by Romero-Sanchez et al., in natural
stone. Natural stone’s thermal properties are improved through exploitation of the
phenomenon of latent heat storage, conducted by many computational and
experimental studies.

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Figure 6: Typical External Wall Layers Schematic Diagram
Concrete pilot houses were constructed with experimental techniques.
Covering of pilot houses was done with transventilated designs for facade, with the
usage of natural stone, called ‘Spanish Bateigazul’. It showed the results that a
profile of smooth indoor temperature can be obtained with the implementation of
the phase change materials. The experiment also anticipated reduction of
consumption of energy and human comfort improvement. According to Izquierdo-
Barrientos et al., (Izquierdo-Barrientos et al., 2012), the PCM influence in external
building walls and roof are studied. Analysis of various external building roofs and
wall configuration was done for a typical roof and wall of the building, through
varying the layer location of the phase change material, orientation of roof and
wall, ambient conditions and phase transition temperature of the phase change
material. The above figure shows the roof and wall schematics. The roof and wall
shows the standard construction of Spanish and it has cement layer of 15 mm
thickness, firstly and then the layer is followed by two brick wall layers having
thickness of 115 mm and 40 mm, having the insulation layer of 40 mm thickness,
in between the layers of the bricks. Then a plaster layer of 15 mm is placed on the

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building interior. It makes use of a finite difference technique to solve and develop
numerically, for the model called a ID transient heat transfer. In winter, there is no
reduction is observed significantly, in the total lost heat, regardless of the phase
change material transition temperature or orientation of the roof and wall.
However, there were significant variations observed in the total heat gained, in the
period of summer, because of the solar radiation fluxes elevated.
Analysis of the comparative PCM copolymer composite roof and wall board
thermal performance was done analytically, by Kuznik and Virgone (2009) The
room of test is composed of two different enclosures, such as Test Cell 1 and Test
Cell 2, as shown in the Figure, below.
Figure 7: Experimental Setup
The volume of the test cell was 3.10 m x 3.10 m x 2.50 m. the cell was
bounded, by volumes of air, on five sides and regulated at fixed temperature. The
other and sixth face has got glazed faced, isolating the test cell and set apart from

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the climatic chamber. The finally obtained results have shown that the temperature
of air is decreased up to the temperature of 4.20C, in the room, which has used the
phase change material. Enhancement of the comfort is the significant factor, when
the temperature of surface is considered and the green rooftop enhances the natural
convection possible in the room. Moreover, compared with the non-PCM
composite, the phase change material copolymer composite green rooftop does not
allow the existence of thermal stratification. The performance of thermal and
energy was assessed by Chan (2011), for a residential building having integrated
with the phase change material external roof and walls, in the bedroom and living
room. It made use of a typical residential fault with no wallboards made of phase
change material, as the base case, in order to compare. The results of the computer
simulation has showed that the residential flat living room, having its facing to
west, integrated external roof and wall provide a decrease significantly,
comparatively, in their in the temperature of the interior surface, up to 4.14%. It
allowed annual saving of energy up to 2.9%, obtained when the air-conditioning
system was used and the payback period of energy was estimated to have the total
years of 23.4.
According to Zwanzig et al., (2013), the 1D transient equation, through
multilayered envelope of the building for phase change material energy saving
potential study, for the residential homes. The study has incorporate the phase
change material composite roof and wallboard into the roof and walls of the
regular residential building, across different zones of climate, was examined. The
results of the simulation have shown that the optimal location chosen for using for
the placement of the phase change material, within the envelope of the building
depends on the values of resistance, between the layer of phase change material
and the exterior conditions of the boundary. However, as opposite to this, the roof
and wallboard composite made from the phase change material showed the

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reduction in the consumption of energy, during the winter and summer and shift of
the peak load of electricity during the summer period.
A fast and new 1D analytical model was proposed by Mirzaei and
Haghighat, for the applications of PCM-TES, in the simulation programs of
building. The resistor capacity circuit model accuracy concept, containing variable
capacities for the capacitor and resistor depends significantly on various circuits of
synchronized RC. The results obtained from the theoretical investigation and
temperature regulation effects analysis, obtained from the phase change material
incorporation in a cavity wall of building, was summarized by Haung et al. (2006).
Several quantities of phase change material with temperatures of phase change, of
280 C and 430C were incorporated into the roof and wall construction selection.
The phase change materials are considered to be attached directly to the masonry
roof and wall, as shown in the following figure.

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Figure 8: Schematic Diagram Illustrating the PCM Heat Transfer
The key benefit of using the phase change material for green rooftop and
walls has been explored and evaluated by de Gracia et al., (2010), in typical
Mediterranean buildings, by evaluating the environmental impact with the usage of
the PCM. The efforts are made to highlight and discover the critical issues, through
the LCA (Life Cycle Assessment), and three hypothetical scenarios are developed,
studied and proposed. The critical issues discovered and proposed are varied types
of phase change material, varied temperature control systems or varied conditions
of weather. It showed the results as the following.
1. When the phase change material are added, in the envelope of the
building, either as a roof and top, the consumption of energy gets

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decreased during the operation of building, however, there would no
global impact reduction, throughout the building lifetime.
2. The hydrated salts usage presents an impact of manufacturing that is
usually, 75% lower, compared to the paraffins.
3. An impact reduction is shown by the LCA for the real cubicles, to 37%,
while adding the disposal PU (PolyUrethane) to the REF (Reference
Cubicle).
The optimal value for the phase change material roof and wallboard
thickness was investigated by Kurznik et al., (2008). The roof and wallboard of the
phase change material was used in the bulldogs made of lightweight material so
that the fluctuations of room air temperature can be reduced. The description of the
test wall can be shown as in the Figure following.
Figure 9: Composition of Test Wall
The roof and wall are composed of 2 cm, outside the wood of 10 cm
thickness and variable thickness of the phase change material, with a plaster of 1
cm and tested. The optical value of thickness was calculated by developing

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CODYMUR, an in-house numerical code. The final results indicate that the
existence of the optical value is according to the fluctuations of the daily internal
and external temperature.
PCM as Internal Layer of Roof or Wall
The building structure thermodynamic models with the use of the phase
change material are presented for analysis of their effects on the performance of
the building energy at various conditions. The building structure physical dynamic
model integrated with the SSPCM (Shape Stabilized PCM) was validated and
developed. This model shows the roof and wall by two capacitances and three
resistances and it also shows the layer of the phase change material, by two
capacitances and four resistances, as shown in the following Figure.
Figure 10: SSPCM Wall Schematic and Simplified Dynamic Building Model
Schematic
Parameter identification is the key issue considered for this model. A few
models of the phase change materials with the good accuracy and detailed physics
in the simulation of the building structure thermodynamic behaviour, were

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integrated with the layers of the phase change materials. The results of validation
show that the medial walls and light walls integrated with SSPCM can be
represented accurately.
Dynamic simulation of the computational fluid was used for the phase
change material clay roof boards and wall boards effectiveness, towards the non-
air-conditioned spaces peak indoor temperature reduction during the months of the
summer (Gowreesunker & Tassou, 2013). The final results indicate that the clay
roof and wall boards of the phase change materials can reduce the indoor spaces
peak temperature, by 3 K, when compared with the plasterboards used traditionally
and conventionally and they can prevent problematic overheating during the
months of the summer.
The clay board performance is based on the quantity of the phase change
material, external and internal heat gains and quantity of the Phase Change
Material. As opposed to that, a test cell having the 1.3 m x 0.8 m x 1.4 m internal
dimensions having 1.3 m x 0.8 m galzed facade was constructed for a controlled
environment, where in the air transient behaviour and phase change material is
possibility investigated. The structures of the ceiling, floor and wall are made from
the plywood of 48 mm, insulation of 90 mm and plywood having skimmed phase
change material boards of clay of 18 mm dimensions, placed on the internal ceiling
and walls surface only, as shown in the following figure.

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Figure 11: Construction of Experimental Wall
The performance of the phase change material is analysed experimentally,
by Lidia et al (2012), in a scenario with the thermal gains internally. The
experiment was performed, with three various cubicles, having their internal
dimensions of 2.4 m x 2.4 m x 2.4 m, located in Spain, Puigverd de Lledia.
Construction of teh cubicle systems is used as the following.
1. Traditional brick system is used to build the REF and it is based on two
brick layers without insulation and having enough air gap.
2. Traditional brick system is used to build cubicle of PU, having the spray
form PU of 3 cm and 5 cm, in the roof and in the wall respectively.
3. The cubicle of phase change material has got built, similarly, as the cubicle
of previous, but having a layer of phase change material on the roof and in
the western and southern walls.
The panels of CSM, having Rubitherm (rt-27 PRAFFIN, are placed on the
PU internal side. The summer period results indicate that the cubicle of the phase
change material stores the dissipated heat, which was produced by means of

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internal loads, so that the dissipation of heat is limited to the external environment.
Higher fluctuations of tempera rue are present in the REF, in the envelope, such as
27.5 0C to 240 C, compared to the rest of cubicles having the insulation of 280 C to
260C, as shown in the following figure.
A thermal comfort variability comparative assessment is provided by the
summary made by Francesco and derived from various integrated phase change
material into the internal Trombe wall partition and exposed to the mild, hot and
cold climates. Energy-Plus software is used for modelling and simulation of a
simple test room with the dimensions of 5 m x 5 m square plant, having two walls
that get exposed to the south and north. Modelling of the south wall was done as a
lightweight roof and wall that is insulated, having its own weight, lower compared
to 100 kg per m2, having window of double and glazed. The following figure
indicates the modelled test room schematic section.
Figure12:Test Room and Partition
The simulation has shown the result that in the climates of mild temperate
and cold, the phase change materials integration on the external surface of the

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Trombe wall intermediate partition has given an optimal fluctuation reduction in
the inside temperature fluctuations and the stable values are remained stable.
Testing of the two identical rooms is done, for assisting the roof and wall
board of the phase change material, use for the tertiary building renovation. A
single room is taken and equipped with the roof and wall boards of the phase
change material in the lateral walls and whereas the other ceiling and other walls of
the other room are not equipped. It indicates that the ceiling and wall boards of teh
phase change material enhance the occupant’s thermal comfort, because of the
radiative effects and air temperature effect of the ceiling and walls. Different kinds
of composite system of roof and wall, incorporating phase changing materials, are
proposed by Diaconu and Cruceru (2010). This new system of wall has 3 different
functional layers, expressed with 1 to 3 numbers, as shown in the following figure.
Figure 13: Composite PCM Wallboard Structure
Integration of the phase change material is done with the building material
for the outer layers, and the middle layer has the regular and conventional thermal
insulation. The roof and wallboards of the PCM variable thermo physical
properties were accounted by the enthalpy method. It has been identified that the
outer layer of the phase changing material roof and wallboard prevents a

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temperature excessive increase for the interface of the insulation. Such effects are
resulted for wider range of values of melting points for the layer 1, which is
incorporation with phase changing material.
METHODOLOGY
PCM with Green Rooftop System
Initially, inorganic eutectic thermal storage system based on the phase
change material is used for the conservation of energy in buildings. Then an
experimental setup can be made by constructing two test rooms that are identical
and has the dimensions of 1.22 m x. 1.22 m x 2.44 m. One room has to be built
with phase change material panel, in between the rooftop slab and bottoms
concrete slab and another one without phase change material, on the roof.
Insulation has to be done for the inner walls, except the ceiling of the constructed
rooms, by thickness of 6 mm plywood, having all sides for the studying the sole
phase change material panel effect, on the roof. The panel of the phase change
material has to be made with the stainless steel having the dimensions of 2 m x 2
m, with the 2.54 cm thickness. Inorganic salt hydrates material has to be taken by
stainless steel, as the phase change material. The inorganic salt hydrae has the
combination of 48% CaCl2 + 47.3 % of H2o + 4.3% of NaCl + 0.4% of KCl. The
room temperature has to be measured, for any variation, during the experiment.
Similar experiment setup has to be done for the study of the double layer PCM
effect, for the roof of building. Reference case is provided by constructing one
room with no phase change material, on the roof, so that experimental room can be
compared (Pasupathy & Velraj, 2008).

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Figure 14: Roof Cross-Sectional View with and without PCM Panel
The green rooftop cross-sectional views can be considered as the above
figure, for both the material with and without PCM. Then finite volume method
has ot be used for developing the mathematical model, for predicting the PCM
made roof thermal behaviour.
The results are to be noted and studied and the effect of the environment has
to be found on the concrete slab inner surface, since all the energy of heat has to be
absorbed by the phase change material, within the green rooftop. The study has to
be continued to find the fluctuations possible, in the phase change modulation
ceiling, where the green rooftop is used. The ceiling of the non phase change
modulation room also has to be observed to find the immediate external
environment influence.
Simulation
Simulation with Gesture Recognition Toolkit and Pulse Code Modulation
GRT helps in professing in combination with the graphical user interface.
The temperature obtained after designing and placing the green roof top, made by
the phase change material, is received as an input to the design software. This real
time data about the temperature is taken from the sensors. It can be done with the
help of the OSC (Open Sound Control). Then the simulation is performed to see,
how the temperature gets accumulated. And the most important observation of the

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output is done by measuring two important things. The first thing is the
consumption of energy, while the development and making of the green rooftop
with the help of the phase changing material. The other important factor to observe
is the thermal comfort that it can provide to the internal area of the closed room.
The simulation has to be done for both the two important seasons in the
environment, summer and winter. The analysis has to be performed differently for
the temperature of the summer and winter with the humidity, set according to the
season.
Then after the processing and simulation is done, then the processing is
performed. The files are then to be saved by saving the dataset to the file. Then the
dataset has to be loaded back from the file. Then a classifier has to be selected in
the GRT GUI. The selected algorithm for classification has to be trained, with the
help of the training dataset. The trained classification model has to be used, for
prediction of the real time data class and then, these results are to be streamed,
back to the processing.
Alternately, pulse code modulation can be done, for the simulation of the
building designed with the phase change material, for the building with green
rooftop.
The study also has to be conducted for measuring and studying the storage
of the thermal energy, after setting up the green rooftop with the phase change
modulation. The effect and extent of influence of the phase change material has to
be experimented and studied for the storage of the heat. The high energy storage
density has to be measured, while the material for green rooftop is made with the
phase change material.
Having studied and understood the basic purpose and researches done on the
phase change material and the respective experiments, this is the experiment and
study that is expected to be done in the future. Design software is going to be used

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for building the structure as well as giving the real time data and to perform the
simulation. The simulation is going to be performed with the GRT software, for
building the structure and conducting the full-fledged software.
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