Sharma et al. [22] studied the changes in the melting point,
latent heat of fusion and specific heat of PCMs such as stearic acid,
acetamide and paraffin wax, both laboratory-grade and commercial-
grade, after a repeated number of melting/freezing cycles.
Stearic acid melted over a range of temperatures but was
thermally stable. Acetamide and paraffin wax showed reasonably
good stability throughout 300 melting/freezing cycles and could
be considered as promising PCMs. Acetamide absorbed moisture
from surrounding, however. As mentioned by Abhat [12],
paraffins qualify as energy storage materials due to their
availability in a large temperature range and high heat of fusion.
Furthermore, paraffins are known to freeze without any supercooling.
A major drawback of paraffins is the low thermal
conductivity. This problem is addressed through an increase of
the surface area of heat transfer between the heat transfer fluid
(HTF) and the PCM. The development of a latent heat storage
system involves an understanding of heat exchanger and thermal
storage material. Therefore efforts have been focused on the
development of the heat exchanger configurations such as shelland-
tube, double pipe, plate or spherical shells and also on phase
change materials. The use of finned tubes aswell as metal fiber and
metalmatrix, for example, resulted in an increase of 1- to 5-fold of
the effective thermal conductivity of the PCM and hence the rate
of heat transfer [23]. Esenet al. [24] studied an energy storage and