Page 99 - Polymer-based Nanocomposites for Energy and Environmental Applications

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Nanoclay and polymer-based 3

nanocomposites: Materials for
energy efficiency

N. Zari, M. Raji, H. El Mghari, R. Bouhfid, A.e.K. Qaiss
Moroccan Foundation for Advanced Science, Innovation and Research, Rabat, Morocco

3.1 Introduction

The prompt development of global economics generates a high consumption of energy
resources as electricity or fossil fuel, thus resulting in depletion of reserves of fossil
fuels (not renewable) and an increase in the emission of harmful gases into the envi-
ronment that includes carbon dioxide (CO 2 ) and methane. These gases are responsible
for climate changes and environmental pollution [1]. Definitely, the building applica-
tions are largely responsible for a significant part of total commercial energy con-
sumption [2]; it generally accounts around 32% of the total amount over the past
20 years, according to the International Energy Agency (IEA) [3].
Nowadays and due to the rapid exponential growth of the world population, house-
holds, and developed area on our planet, it has projected a tremendous increase in the
utilization of the consumed energy that has given a potent impetus to develop new
products with the aim of reducing dependency on the nonrenewable energy sources
and then contributing to a more efficient environmentally friendly energy use. In this
regard, the energy storage technology is an effective way to reduce energy consump-
tion in the building sector [4]. Withal, the use of energy storage materials enables the
reduction of the gap between supply and demand and also the improvement of the
overall performance and reliability of the building envelope [4]. This class of modern
materials possesses many operational advantages, such as small unit sizes, low weight
per unit storage capacity, smaller temperature swing, and high storage density at
nearly isothermal conditions. There are different forms for the energy storage:
mechanical, electric, and thermal (TES). This latter is the most widespread in the field
of construction. It can be accomplished by using either sensible heat, latent heat, and
thermochemical or the combination of all. Among above, latent heat is the most used
due to its ability to provide high energy storage density and its capacity to absorb and
to release total heat energy when it undergoes a phase change from solid-liquid state or
liquid-gas state or vice versa at a constant temperature. So far, the latent heat storage
has spawned various building materials by incorporating a phase-change material
(PCM), which is surely employed and extensively studied as building energy
conservation [5].

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