Page 111 - Polymer-based Nanocomposites for Energy and Environmental Applications

Nanoclay and polymer-based nanocomposites: Materials for energy efficiency 87

than the use of PCM wall panels [54]. Zhang et al. investigated the thermal behavior of
cement mortar prepared with n-octadecane and expanded graphite (EG) composite
PCM [55], where the mass percentage of n-octadecane/expanded graphite composite
PCM in the thermal energy storage cement mortar (TESCM) samples varied from 0.5
to 2.5 wt%. It was found that when the percentage of n-octadecane/expanded graphite
composite PCM in TESCM increased the compressive strength and thermal conduc-
tivity of TESCM decreased with the values of 55 and 15.5%, respectively. From ther-
mal energy storage performance test on small test room (100 100 100 mm), it was
found that TESCM containing n-octadecane/EG composite PCM causes a reduction
of energy consumption by reducing the indoor temperature variation. Thus, the
TESCM containing n-octadecane/EG composite PCM are promising materials for
building applications.
In order to study the possibility of using microencapsulated PCM in concrete,
Cabeza et al. investigated the thermal performance of two real-size concrete
(2 2 3m) (Fig. 3.7) during the years 2005 and 2006 in Spain [56,57]. The panels
(south, west, and roof walls) of the first cubicle were microencapsulated with 5 wt%
PCM with melting point of 26°C and latent heat of fusion 100 kJ/kg. The second one
was construct with standard concrete. The results showed that the compressive
strength and the tensile splitting strength of the microencapsulated PCM concrete
were reached over 25 and 6 MPa, respectively. The result exhibited high energy stor-
age in the walls with the microencapsulating PCM compared with conventional con-
crete without PCM, leading to an improved thermal inertia and lower inner
temperatures.
In order to increase the thermal comfort inside buildings, Sa et al. developed and
characterized a new construction material by incorporating 25% of microencapsulated
paraffin powder into plastering mortar [58]. Two small-sized test cells one with and
without PCM plastering mortar, having an internal hollow volume of
(26 26 26 cm), were tested in climate chamber (58 76.5 75 cm) (Fig. 3.8).
The test cells have been subjected to realistic temperature cycles at high temperature

Fig. 3.7 Photo of experimental house, Spain [56].