Experiment on heat storage characteristic of microencapsulated phase change material slurry

Heat storage experiment by natural convection in rectangular enclosures heated from bottom has been conducted with fluid slurry composed of microencapsulated phase change material (PCM). The microencapsulated PCM is prepared by in-situ polymerization method, where the core materials are composed of several kinds of n-paraffin waxes (mainly nonadecane) and the membrane is a type of melamine resin. Its slurry mixed with water is used in this study, and shows a peak value in the specific heat capacity with latent heat at the temperature of about T=31 °C. The influences of the phase change material on heat storage and the heat transfer process, as well as effects of PCM mass concentration Cm on the microcapsule slurry, temperature of heat storage TH and a horizontal enclosure height H are also investigated. Transient heat transfer coefficient α, heat storage capacity Q and completion time of heat storage tc are discussed.

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► The PCM in the slurry could promote natural convection heat transfer.
► Heat storage in the PCM microcapsule slurry mainly occurs at the beginning of the process.
► An increase in the heat storage temperature cannot be fully guaranteed to shorten the completion time of heat storage.
► The completion time of heat storage has a local maximum value and a local minimum value.