Experimental Evaluation of Phase Change Material Blister Panels for Building Application

Abstract

Phase Change Materials (PCMs) are characterised by their capacity to absorb available thermal energy, store it, and passively release it by utilizing latent heat during phase change, thus reducing temperature peaks and improving thermal comfort. This paper experimentally investigates the feasibility of a novel blister PCM panel for ceiling tile applications. Experimental panels enhance the thermal conductivity of the PCM with the addition of steel and aluminium wool particles at 3.77 wt.% and 23 wt.%, respectively. During the experimental procedure, the blister panels where able to absorb the heat coming from the environmental chamber, proving that the encapsulation material was able to promote the heat exchange. Furthermore, the PCM enhancement indicates that both the aluminium and steel wool particles improved the blister panel thermal performance. These results were confirmed by thermal conductive, calculated at 0.733 W/(m K) for the base panel, 0.739 W/(m K) for the aluminium wool, and 0.784 W/W/(m K) for the steel wool. The experiment suggest that the application of PCM blister ceiling tiles can be considered as an innovative method for thermal performance control and energy saving.

Full text

1. Introduction
Phase change materials (PCMs) absorb, store, and passively
release available thermal energy via latent heat transfer
during phase change, thereby reducing peak demand and
improving thermal comfort (Salunkhe and Shembekar,
2012; Kalnæs and Jelle, 2015; Wang et al., 2020). The ther-
mal performance of PCMs is based on their melting point,
thermal conductivity, and energy storage density. For this
reason, when applied as energy storage, they require an
instant melting and solidification point (Ji et al., 2014; Ma,
Lin and Sohel, 2016).
Paraffins, salt hydrates, and fatty acids are the most
commonly used PCMs, having a melting temperature
within human thermal comfort, making them suitable
for building applications. However, such materials have
major drawbacks, including low thermal conductivity,
especially for organic PCMs. As a result, performance
enhancements of PCMs are eagerly researched, to develop
improved techniques (Fan and Khodadadi, 2011). Such
methods require the addition of highly conductive mate-
rials, which can be done by modification of the encap-
sulation material, the shape of the container, using heat
pipes, heat exchangers, micro- and macro-encapsulation,
or the addition of highly conductive nanoparticles in
the base fluid, creating nano-enhanced PCM (Babaei,
Keblinski and Khodadadi, 2013; Ma, Lin and Sohel, 2016).
Further techniques proposed the integration of metallic
fins, foam wools, and graphite (Ji et al., 2014; Fan et al.,
2013). The literature views of PCM enhancement mate-
rials have identified graphite, aluminium, and carbon as
the most frequently applied materials for organic PCM
enhancement.
There are two methods to integrate PCM in building ele-
ments. The first method, “shape-stabilized”, considers the
direct addition of the PCM into a building element, such
as a gypsum wall (Silva, Vicente and Rodrigues, 2016). The
second method requires the PCMs to be encapsulated for
technical use, as otherwise the material would disperse
from the location (Cabeza et al., 2011). For this reason,
the encapsulation method is the most commonly used
form of integration and has become a topic of analysis
in recent years. The geometry of the encapsulation can
take any shape, but the most popular forms are tubes,
pouches, spheres, and panels. Encapsulation geometry
could potentially be harnessed as a heat enhancement
method, improving the thermal conductivity of the PCMs
(Amin, Bruno and Belusko, 2014). Additional benefits of
encapsulation include the capacity to counteract phase
segregation, which is a regular phenomenon particularly
prevalent with salt hydrates, in which the high storage
density of the material disperse in layers, leading to the
decline in the storage efficiency.
Velasco-Carrasco, M, et al. 2020. Experimental Evaluation of Phase
Change Material Blister Panels for Building Application.
Future Cities
and Environment,
6(1): 6, 1–7. DOI: https://doi.org/10.5334/fce.84
Department of Architecture and Built Environment, Faculty of
Engineering, University of Nottingham, UK
Corresponding author: Mariana Velasco-Carrasco
(mariana.velascocarrasco@nottingham.ac.uk)
TECHNICAL ARTICLE
Experimental Evaluation of Phase Change Material
Blister Panels for Building Application
Mariana Velasco-Carrasco, Ziwei Chen, Jorge Luis Aguilar-Santana and Saa Riat
Phase Change Materials (PCMs) are characterised by their capacity to absorb available thermal energy,
store it, and passively release it by utilizing latent heat during phase change, thus reducing temperature
peaks and improving thermal comfort. This paper experimentally investigates the feasibility of a novel
blister PCM panel for ceiling tile applications. Experimental panels enhance the thermal conductivity of
the PCM with the addition of steel and aluminium wool particles at 3.77 wt.% and 23 wt.%, respectively.
During the experimental procedure, the blister panels where able to absorb the heat coming from the
environmental chamber, proving that the encapsulation material was able to promote the heat exchange.
Furthermore, the PCM enhancement indicates that both the aluminium and steel wool particles improved
the blister panel thermal performance. These results were conrmed by thermal conductive, calculated at
0.733 W/(m K) for the base panel, 0.739 W/(m K) for the aluminium wool, and 0.784 W/W/(m K) for the
steel wool. The experiment suggest that the application of PCM blister ceiling tiles can be considered as
an innovative method for thermal performance control and energy saving.
Keywords: blister panels; energy storage; phase change materials; thermal performance
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Velasco-Carrasco et al: Experimental Evaluation of Phase Change Material Blister Panels
for Building Application
Art. 6, page 2 of 7
Popular materials for encapsulation include plastic
containers, such as polypropylene and polyurethane; for
metals, copper and aluminium; and for inorganic mate-
rials, silicones and resins (Salunkhe and Shembekar,
2012). In the case of the salt hydrates, their corrosive-
ness affecting metals tends to reduce possible encapsu-
lation solutions, thus plastic materials are more suitable.
Basic encapsulation requirements include a heat trans-
fer surface, structural stability, corrosion resistance, and
the ability to offer thermal stability (Bland et al., 2017).
Table 1 discusses potential containers materials for PCM
encapsulation (Jacob and Bruno, 2015).
The encapsulation can be classified by the size of the
container surrounding the PCM. Macroencapsulation
covers diameters from 1 mm or higher, and is the most
used method for PCM encapsulation. Microencapsulation
covers from 1 μm to 1 mm, and nanoencapsulation
refers to diameters of less than 1 μm (Jacob and Bruno,
2015). Microencapsulation represents higher complexity
than macroencapsulation, but the development of new
technological advancements has introduced nano-scale
encapsulation, resulting in higher heat transfer rates in
comparison to macroencapsulation (Hawlader, Uddin and
Khin, 2003; Khudhair and Farid, 2004).
The aim of this paper is to experimentally investigate the
feasibility of a novel blister PCM panel for ceiling tile appli-
cations. Different encapsulation methods were studied in
order to determine the most adequate implementation
according to thermal performance. Laboratory analysis of
different encapsulation panels was carried out, favouring
the blister encapsulation method. A set of three samples
were tested, with INERTEK 23 as the base fluid: a base
panel, containing only pure PCM; a second composite sam-
ple, integrating aluminium wool at 3.77 wt.%; and a third
composite, using steel wool at a concentration of 2.3 wt.%.
2. Methods and Materials
2.1. Experimental setup
An experimental set-up was prepared to analyse the effect
of the blister panels and enhancement methods. A set of
experiments performed in the Environmental Climatic
Chamber developed by SJJ System Services Ltd. (Serial No.
A2520). The experimental set-up consisted of a control
box of 70 × 67 × 73 cm dimensions, in which the blis-
ter PCM panels where allocated over a metallic mesh.
The temperature measurements were made using type
K thermocouples, and all readings were collected by the
data logger (DT85), with a standard deviation of ±0.3 °C.
Sensors were placed in the inlet, outlet, and inside the
PCM blister panel, as shown in Figure 1. Both the inlet
and outlet had openings of 18 cm in diameter, with airflow
coming from the Environmental Chamber blown through
with the assistance of an electric fan.
2.2. Methodology
The experiments consisted of creating an airflow through
the control box at a desired temperature, in order to
analyse the thermal performance of the PCM blister
panel. The aim of the laboratory set-up was to detect the
panel temperature to analyse the energy storage capacity.
In the first experimental set-up the temperature was
maintain constant at 28 °C to ensure the melting tempera-
ture of the PCM, whose enthalpy values range between 18 to
28 °C. The chamber temperature was stabilized for an hour
before the testing period. After this interval, the panels were
allocated over a metal mesh and the experiment began. The
testing time was of 6 hours, and each test was repeated three
times, during which the average temperature was noted.
In the second test, the chamber temperature was
increased in two-hour intervals in order to analyse the
response of the temperature over the panels. In this case,
the starting temperature was considered at 23 °C and the
finishing temperature was stablished at 27 °C. As in the
first experiment, the chamber temperature was stabilized
an hour before the testing period. The testing time was
6 hours, and each test was repeated three times, during
which the average temperature was noted.
The data extracted from the experiment was analysed
in order to determine the thermal characteristics of the
enhancement material over the PCM blister panels. The
specific heat capacity of the PCM was calculated through
the addition of the enhancement material to the blister
panel using the following equation:
()
1
composite PCM PCM matrix PCM
C CXC X
= +−ii
where:
Ccomposite is the specific heat capacity of the composite,
J/kgK
CPCM is the specific heat capacity of the PCM, J/kgK
Table 1: Shell materials for PCMs.
Group Proposed materials Advantages Disadvantages Potential applications
Metals Steel, aluminium, copper - High thermal conductivity
- Encapsulation by electroplating
- High thermal stability
- Strong structure
- Potential corrosion
- Higher cost
High-temperature
applications
Inorganic Silicon, titanium
dioxide, sodium silicate,
silica, gelatin+acacia,
melamine-resin
- High thermal stability
- High thermal mechanical
strength
- Inexpensive
- Leakage risk Industrial processes
Plastic Polyolefine, propylene,
polyester, polystyrene,
polyethylene
- Inexpensive
- Chemical and physical
encapsulation methods
- Relative low thermal
stability
- Low thermal conductivity
Building integration
Food industry

Velasco-Carrasco et al: Experimental Evaluation of Phase Change Material Blister Panels
for Building Application
Art. 6, page 3 of 7
XPCM is the weight ratio of the PCM to the composite
Cmatrix is the specific heat capacity of the matrix material,
J/kgK
2.3. Preparation of the composite-PCM
The sample PCM used in this research was a micro-
encapsulated phase change material (MEPCMs) with
granular particles ranging from 5 to 25 μm; the industrial
reference is INERTEK 23©. The principle of microencapsu-
lation is based on creating an envelope around the micro-
particles in the phase change, improving the heat transfer
to the surroundings while avoiding phase segregation.
INEREK 23 phase transition lies in the human comfort
zone temperature; moreover, it has high latent heat, pro-
vides thermal stability, and avoids phase segregation. To
enhance the thermal conductivity of the INERTEK 23,
the addition of steel and aluminium wool particles was
considered due to their low cost, light structure, and high
thermal conductivity, germane to ensuring an extended
contact area with the base material.
The nano-enhanced PCM was integrated using a two-step
method, in which both materials were created separately.
Generally, a powder is mixed with nanoparticles with the
help of magnetic force agitation. Due to the high surface
area and surface activity the powder particles tend to aggre-
gate into the wool particles. The distribution of the mate-
rials was arbitrary (Figure 2), and the particles fluctuated
in size, geometry, and volume, as shown in Table 2. Due
to the manufacturing process the proportion of the com-
posite varies; the proportion of the composite varies and
were equivalent to the weight percentages of 3.77 wt.% for
aluminium wool and 2.3 wt.% for the steel wool.
2.4. Panel design
The blister panel consist on an individual plastic blister
measuring 15 × 15 × 2 cm. A schematic of the panel is
shown in Figure 3. The PCM composite was allocated into
the blister container and sealed with thermal conductive
tape. The blister design promotes the airflow throughout
the panel, facilitating the melting process of the PCM by
Figure 1: Schematic setup of the panel rig.
Figure 2: PCM blister panel schematic distribution.
Table 2: PCM blister panel composition.
Panel Name PCM Enhancement material PCM mass (kg) Enhancement mass (kg) Total mass (kg)
Base Panel INERTEK 23 N/A 0.538 N/A 0.538
Compound 1 INERTEK 23 Aluminium wool 0.371 0.014 0.385
Compound 2 INERTEK 23 Steel wool 0.385 0.009 0.399

Velasco-Carrasco et al: Experimental Evaluation of Phase Change Material Blister Panels
for Building Application
Art. 6, page 4 of 7
increasing the contact area. To replicate a ceiling tile of
45 × 45 cm, an array of 3 × 3 blisters was added, having a
total of 9 panels, as shown in Figure 4.
2.5. Thermal conductive analysis
The thermal conductivity analysis is one of the main param-
eters considered for the application of a composite-PCM for
thermal energy storage buildings. The thermal conductivity
of the different samples was calculated using the HFM-100
Heat Flow Meter method, which is a popular technique
for thermal conductivity and thermal resistance measure-
ments (Figure 5). The equipment contains two flux sen-
sors with a thermal conductive range between 0.005 to
0.5 W/(m K). The temperature range varies from –20 °C to
70 °C, with accuracy ±3%. To ensure the accuracy of the
measurement, expanded polystyrene board was tested as a
calibration material. The operational temperature was set
at 30 °C for the hot plate and 10 °C for the cold plate.
3. Experimental Results
In the first experimental set-up the environmental cham-
ber temperature was kept constant at 28 °C.
Figure 6 shows the panel temperature of the different
samples. It can be observed that the temperature of the
panels increased rapidly, as the chamber’s initial temper-
ature was higher than the PCM melting point. After the
initial surge, compounds 1 and 2 stagnated after 14,005
seconds (4 hr) of testing, while the base panel maintained
temperature increments for most of the testing period.
The base panel had the lowest values, reaching a maxi-
mum of 25.97 °C, with compound 1 and compound 2 pre-
senting values of 26.17 °C and 26.34 °C, respectively.
The second experimental set-up compared the temperature
variation of the three blister panels, as shown in Figure 7. The
experiment was maintained for 21,600 seconds (6 hr), with
2 °C increments every 2 hrs. The starting temperature was
23 °C and the finishing temperature was 27 °C. The base
panel and compound 1 presented similar behaviour, with
a slightly higher temperature range in the aluminium mix-
ture, reaching 25.66 °C and 25.93 °C, respectively. The com-
pound 2 panel temperature levelled-up once the second
temperature increment was applied, and from this point
onwards the temperature increased until it reached 27.11 °C.
Based on the experimental results, the specific heat
capacity was calculated to analyse the effect of the
encapsulation method and enhancement material, as
presented in Table 3. The specific heat capacity of the
INERTEK 23 microcapsules was 66 (kJ/kg K) (Djamai, Si
Larbi and Salvatore, 2019); that of the aluminium wool
was 0.896 (kJ/kg K); and that of the steel wool was 0.502
(kJ/kg K), (Singh Rathore, Shukla and Gupta, 2020).
There are two main factors to consider when analysing
Figure 3: Schematic diagram of the blister panel utilized
in the experiment.
Figure 4: Left-set of 9 blister panels. Right-panel testing in the control box.
Figure 5: HFM-100 thermal conductive analysis of the
blister panel.

Velasco-Carrasco et al: Experimental Evaluation of Phase Change Material Blister Panels
for Building Application
Art. 6, page 5 of 7
Figure 6: Test 1 – Blister panels comparison at 28 °C.
the heat capacity. First, the heat transfer performance is
correlational to the PCM mass, thus the base panel pre-
sents higher mass in comparison to the composite pan-
els. Second, the particles distribution in the PCM must
be considered, as the heat transfer rate is determined by
the percentage of the enhancement nanoparticles added
(Abdelrahman et al., 2019).
Results of the thermal conductive analysis found that
the conductivity of the base panel was 0.733 W/(m K).
The addition of the aluminium wool increased the ther-
mal conductivity to 0.739 W/(m K); furthermore, the steel
particles provided thermal conductivity of 0.784 W/ (m K).
From the experimental results, it is clearly apparent that
the addition of the enhancement material improved the
thermal conductivity of the INERTEK 23.
From the experimental results, it is evident that the
composite panels are able to absorb more heat as the PCM
melts, confirming that the aluminium and steel wool par-
ticles enhance heat transfer performance.
4. Conclusions
Ceiling tiles are a practical method to integrate the mate-
rial into building elements, increasing thermal mass,
reducing temperature fluctuations, and assisting in energy
Figure 7: Test 2 – Blister panels comparison with 2 °C increments.
Table 3: Thermal performance analysis.
Property Base panel Compound 1 Compound 2
Storage Heat Capacity (J/g) 200 (PCM) 200 (PCM) 200 (PCM)
Specific Heat (J) 66000 63509 64457
Thermal Conductivity W/(mK) 0.733 0.739 0.784
Temperature Difference (°C) 2.29 3.12 3.4

Velasco-Carrasco et al: Experimental Evaluation of Phase Change Material Blister Panels
for Building Application
Art. 6, page 6 of 7
performance by regulating the indoor temperature. The
thermal performance of three different PCM blister pan-
els was evaluated in terms of the heat absorption capac-
ity and thermal conductivity. INERTEK 23 was selected as
the base PCM, having a phase transition range compatible
with the human thermal comfort temperatures. In this
study, aluminium and steel wool were selected as compos-
ite materials to enhance the thermal performance of the
PCM blister panels.
The results suggest that the application of the PCM blis-
ter ceiling tiles can be considered as an innovative method
for building incorporation. During the experimental proce-
dure, the blister panels were able to absorb the heat coming
from the environmental chamber, proving that the encap-
sulation material was able to promote the heat exchange.
Furthermore, the PCM enhancement indicates that both
the aluminium and steel wool particles improved blister
panel thermal performance. This result was confirmed by
thermal conductive analysis. The base panel presented a
thermal at 0.733 W/(m K), 0.739 W/(m K) for compound 1,
and 0.784 W/(m K) for compound 2. The latter, with steel
enhancement, can be considered as the sample which has
the highest thermal performance.
Acknowledgements
This work was supported in part by the Science and
Technology Council of Mexico (Consejo Nacional de
Ciencia y Tecnologia, CONACYT).
Competing Interests
Saffa Riffat is the Editor in Chief of this journal and was
removed from all editorial duties involving the review and
processing of the submission.
References
Abdelrahman, HE, Wahba, MH, Refaey, HA, Moawad, M
and Berbish, NS. 2019. Performance enhancement
of photovoltaic cells by changing configuration and
using PCM (RT35HC) with nanoparticles Al2O3. Solar
Energy, 177 (November 2018): 665–671. Elsevier.
DOI: https://doi.org/10.1016/j.solener.2018.11.022
Amin, NAM, Bruno, F and Belusko, M. 2014. Effective
thermal conductivity for melting in PCM encapsu-
lated in a sphere. Applied Energy, 122: 280–287.
Elsevier Ltd. DOI: https://doi.org/10.1016/j.
apenergy.2014.01.073
Babaei, H, Keblinski, P and Khodadadi, JM. 2013.
Improvement in thermal conductivity of paraffin by
adding high aspect-ratio carbon-based nano-fillers.
Physics Letters, Section A: General, Atomic and Solid
State Physics, 377(19–20): 1358–1361. Elsevier B.V.
DOI: https://doi.org/10.1016/j.physleta.2013.03.040
Bland, A, Khzouz, M, Statheros, T and Gkanas, EI. 2017.
PCMs for residential building applications: A short
review focused on disadvantages and proposals for
future development. Buildings, 7(3). DOI: https://
doi.org/10.3390/buildings7030078
Cabeza, LF, Castell, A, Barreneche, C, De Gracia,
A and Fernández, AI. 2011. Materials used as
PCM in thermal energy storage in buildings: A
review. Renewable and Sustainable Energy Reviews,
15(3): 1675–1695. Elsevier Ltd. DOI: https://doi.
org/10.1016/j.rser.2010.11.018
Djamai, Z, Si Larbi, A and Salvatore, F. 2019. A
Non-parafnic PCM Modied Textile Rein-
forced Concrete Sand-Wich Panel, 453–458.
[Online]. Available at: DOI: https://doi.
org/10.1007/978-981-15-0802-8_70
Fan, L and Khodadadi, J. 2011. Thermal Conductiv-
ity Enhancement of Phase Change Materials for
Thermal Energy Storage: A Review. Renewable
and Sustainable Energy Reviews, 15: 24–46. DOI:
https://doi.org/10.1016/j.rser.2010.08.007
Fan, LW, Fang, X, Wang, X, Zeng, Y, Xiao, YQ, Yu, ZT,
Xu, X, Hu, YC and Cen, KF. 2013. Effects of various
carbon nanofillers on the thermal conductivity and
energy storage properties of paraffin-based nano-
composite phase change materials. Applied Energy,
110: 163–172. DOI: https://doi.org/10.1016/j.
apenergy.2013.04.043
Hawlader, MNA, Uddin, MS and Khin, MM. 2003.
Microencapsulated PCM thermal-energy storage
system. Applied Energy, 74(1–2): 195–202. [Online].
Available at: DOI: https://doi.org/10.1016/
S0306-2619(02)00146-0
Jacob, R and Bruno, F. 2015. Review on shell materials
used in the encapsulation of phase change materi-
als for high temperature thermal energy storage.
Renewable and Sustainable Energy Reviews, 48:
79–87. Elsevier. DOI: https://doi.org/10.1016/j.
rser.2015.03.038
Ji, H, Sellan, D, Pettes, M, Kong, X, Ji, J, Shi, L and Ruoff,
R. 2014. Enhanced thermal conductivity of phase
change materials with ultrathin-graphite foams
for thermal energy storage. Energy & Environmen-
tal Science, 7: 1185. DOI: https://doi.org/10.1039/
C3EE42573H
Kalnæs, SE and Jelle, BP. 2015. Phase change materials and
products for building applications: A state-of-the-art
review and future research opportunities. Energy
and Buildings, 94(7491): 150–176. Elsevier B.V. DOI:
https://doi.org/10.1016/j.enbuild.2015.02.023
Khudhair, AM and Farid, MM. 2004. A review on energy
conservation in building applications with ther-
mal storage by latent heat using phase change
materials. Energy Conversion and Management,
45(2): 263–275. DOI: https://doi.org/10.1016/
S0196-8904(03)00131-6
Ma, Z, Lin, W and Sohel, MI. 2016. Nano-enhanced
phase change materials for improved building
performance. Renewable and Sustainable Energy
Reviews, 58: 1256–1268. Elsevier. DOI: https://doi.
org/10.1016/j.rser.2015.12.234
Salunkhe, PB and Shembekar, PS. 2012. A review
on effect of phase change material encapsula-
tion on the thermal performance of a system.
Renewable and Sustainable Energy Reviews,
16(8): 5603–5616. Elsevier. DOI: https://doi.
org/10.1016/j.rser.2012.05.037

Velasco-Carrasco et al: Experimental Evaluation of Phase Change Material Blister Panels
for Building Application
Art. 6, page 7 of 7
Silva, T, Vicente, R and Rodrigues, F. 2016. Literature
review on the use of phase change materials in glaz-
ing and shading solutions. Renewable and Sustain-
able Energy Reviews, 53: 515–535. Elsevier. DOI:
https://doi.org/10.1016/j.rser.2015.07.201
Singh Rathore, PK, Shukla, SK and Gupta, NK. 2020.
Potential of microencapsulated PCM for energy
savings in buildings: A critical review. Sustain-
able Cities and Society, 53(August 2019): 101884.
Elsevier. DOI: https://doi.org/10.1016/j.scs.2019.
101884
Wang, H, Lu, W, Wu, Z and Zhang, G. 2020. Parametric
analysis of applying PCM wallboards for energy sav-
ing in high-rise lightweight buildings in Shanghai.
Renewable Energy, 145: 52–64. Elsevier Ltd. DOI:
https://doi.org/10.1016/j.renene.2019.05.124
How to cite this article: Velasco-Carrasco, M, Chen, Z, Aguilar-Santana, JL and Riat, S. 2020. Experimental Evaluation of Phase
Change Material Blister Panels for Building Application.
Future Cities and Environment,
6(1): 6, 1–7. DOI: https://doi.org/10.5334/
fce.84
Submitted: 11 November 2019 Accepted: 06 April 2020 Published: 08 June 2020
Copyright: © 2020 The Author(s). This is an open-access article distributed under the terms of the Creative Commons
Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium,
provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.
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