Civil Engineering Reference
In-Depth Information
In addition, the energy redistribution requirements can be effectively met by
using the TES systems integrated with the dedicated cooling and heating systems
in the existing buildings. Energy efficiency in buildings is intensely coupled with
high-performance-materials-based energy redistribution and energy conservation,
which would glean in creating a pleasant and comfortable indoor environment to
occupants. In particular, the assessment of reducing energy consumption using
materials that are thermally efficient and stable on long-term stands vital in
building cooling applications.
From this perspective, research interests towards developing the TES systems
incorporating efficient phase change heat storage materials (PCM), which would
offer energy redistribution requirements, are increasingly popular. Organic PCMs
are highly pronounced in modern times because of their good thermophysical
properties, operating temperature limits, high latent heat capacity, congruent phase
transition, good heat storage capabilities, low supercooling, non-toxic effects,
thermochemical stability and reliability on long-term usage.
However, the successful use of organic PCMs in veracity primarily depends on
their thermal conductivity and heat transfer mechanisms exhibited in charging
(freezing) and discharging (melting) cycles. Incorporation of thermally conductive
materials into the pure (base) PCM would enhance the thermal conductivity, heat
storage or release density, thermal stability and reliability of PCMs. However, the
increased proportion of additives at macrosize may at times descend the heat
storage density of composite PCMs which in turn would produce nonlinear heat
storage characteristics during phase transformation.
As a step forward to the above achievements, research efforts have been equally
put forth to enhance the operational performance of organic PCMs using nanoma-
terials. The relatively high surface-to-volume ratio of nanomaterials enables them to
effectively promote nucleation and heat transfer in PCM. The proper selection and
preparation of nanomaterials paves way for attaining enhanced thermal conductiv-
ity, latent heat capacity and heat transfer performance of PCMs. Nanomaterials
prepared in different structures including nanotubes, nanorods, nanoparticles, etc.,
would exhibit distinct thermophysical aspects when dispersed in pure PCM.
The nucleus of this chapter is devised in a way to provide an outlook of a
variety of the TES systems and with an objective of giving good understanding on
the integration of the TES systems with the existing building architectures, for
achieving enhanced energy savings potential and energy efficiency on a long-term
basis. A brief discussion on the operational strategy and the design aspects of the
TES systems with the relevant information are summarized and presented.
2 Classification of TES Technologies
Thermal energy can be stored as a change in internal energy of a material in the
form of sensible heat, latent heat and thermochemical or combination of these. In
the SHS, the temperature of the storage material increases as the energy is stored,
