Environmental Engineering Reference
In-Depth Information
Phase Change Material Particles
and Their Application in Heat
Transfer Fluids
J. J. Xu, F. Y. Cao and B. Yang
Abstract Phase change materials (PCMs) have received considerable attention for
the application of thermal energy storage and transfer. This chapter discusses synthesis
and characterization of several types of PCM particles, as well as the use of PCMs to
enhance the performance of heat transfer fluids. Two different PCM microcapsules are
introduced first: one comprises solid-liquid PCM paraffin encapsulated in polymer
shell; the other involves solid-solid PCM neopentyl glycol (NPG) core and silica
shell. Then the synthesis of low-melting metallic nanoparticles and NPG nanoparticles
without shells are discussed. The last part of this chapter is dedicated to a new type of
phase-changeable fluids, nanoemulsion fluids, in which the dispersed nanodroplets
can be liquid-vapor PCM or liquid-solid PCM, depending on the PCM properties and
the operating temperature. Material synthesis and property characterizations of these
phase-changeable fluids are two main aspects of this chapter.
1 Introduction
Phase change materials (PCMs) have received considerable attention for the
application of thermal energy storage and transfer, which offer the potential to
reduce energy consumption and in turn lower the related environmental impact
[ 1 - 7 ]. PCMs are capable of absorbing and releasing large amounts of thermal
energy when they undergo phase transition. Latent heat storage materials provide
much higher energy storage density with a smaller temperature difference between
storing and releasing processes, than the sensible thermal storage materials [ 4 , 8 -
10 ]. PCMs' latent heat storage can be normally achieved through solid-solid,
solid-liquid, and liquid-gas phase change.
Xu and Cao contributed equally to this work.
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