In this chapter, we present experimental results and modelings for a divided
system constituted by a tank filled by spherical nodules heated or cooled by a fluid which
passes through it. These nodules contain a phase change material as pure compounds or
eutectics. The industrial application concerns the latent heat storage of the thermal energy.
We present examples in the field of the sub-ambient storage, but our investigations might
be extrapolated at other different levels of temperature. First, we describe the kinetics of
phase transforms in the case of individual nodules and the role of an enhancement of the
heat conductivity by adding divided carbon. We will notice some similitude with the
emulsion because the supercooling phenomenon is also present in spite of the higher
volume of phase change material. In the tanks, we will describe a kind of self-regulation. A
simplified model, in case of the vertical flows, permits the description of the energy storage
either in charge or in discharge mode and explains the self-regulation. The difference with
the emulsions is that, due to a smaller supercooling, we must take into account the
temperature field inside the nodule. The influence of characteristic parameters such as the
flow rates of the fluid or the final inlet temperatures is detailed. The case of the horizontal
tank where natural convection is concerned is evoked. Finally the case of incomplete
discharge modes, often programmed, is described.
Keywords: Charge mode, discharge mode, experimental results, horizontal flow,
latent energy storage, melting, modelings, spherical nodules, storage tank,
supercooling, vertical flow.