Heat Transfer Enhancement of PCM Based Composite Heat Sinks and Thermal Energy Storage Devices
A Finned PCM Heat Sink
Shown above is the Composite Heat Sink (CHS) which is
composed of fins made of a high conducting base material (BM, marked in GREY)
protruding into a reservoir of low conducting, high latent heat storage, Phase
Change Material (PCM, marked in Green). In order to prevent the electronics that
sit on the top wall from overheating, the heat dissipated by them into the CHS
through the top wall should be transferred quickly into the PCM sinks. In other
words, a better CHS would continuously receive heat into the latent heat
storage of the PCM and perform for a longer time without allowing the
electronics to reach unsafe temperatures.
For this to be ensured, a larger heat transfer
(interface) area between the low conductivity PCM and the high conductivity BM
is required, which, by the design in the above figure, requires a certain
number of BM and PCM “fins”. In addition, as the interface area increases (or
as the number of fins increase), an enhancement in the heat storage capacity of
the CHS is expected. The selection of the number of fins is not arbitrary and
requires proper thermal analysis, which is accomplished in our work through a
combination of scale analysis and numerical methods.
The increase in the number of fins with
an increase in the proportion of PCM in the heat sink (more
heat transfer area) is found to be non-linear.
REFERENCE
·
Akhilesh,
R., Narasimhan, A. and Balaji, C., “Method to Improve Geometry for Heat
Transfer Enhancement in PCM Composite Heat Sinks,” Int. J. Heat and Mass Transfer,
(2004, under review).
