Project Title:

Thermal Storage in Plastic Crystal Slurries
Hydrogen Consultants, Inc.
P.O. Box 10454
Franklin E.


Plastic crystal slurries offer unique advantages over other phase chage materials
for thermal storage in space.  Plastic particles, suspended in a liquid carrier,
transform between two solid phases, thereby simulating a liquid-liquid phase change.
Unlike liquid-vapor or solid-liquid phase change materials, the slurries remain in
one physical state.  The weight and delta-Ts, inherent in heat exchangers for other
forms of thermal storage, are avoided because the plastic crystals are in intimate
contact with the liquid.  The liquid inventory of the thermal bus becomes a thermal
storage asset, rather than a weight liability.  Additional slurry storage can be
provided by tanks.

	The thermal and fluidic properties of plastic crystal slurries have been investigated,
and plastic crystals have been tailored to meet NASA's temperature requirements by
solid solution and doping methods.  By studing the compatibility of plastic crystals
with various carrier fluids, a solid/liquid pair can be chosen for use in an experimental
test loop.  Studies of friction factor vs. solid concentrations can clarify the trade-off
between high thermal storage capacity and low pumping power.  Periodic slurry sampling
and fluid component inspection will seek evidence of particle agglomeration and changes
in thermal properties.