A method to evaluate natural convection heat transfer in microencapsulated phase change material (MPCM) slurry: An experimental study

Immersion of microencapsulated phase change material (MPCM) into carrying fluid to form MPCM slurry is an effective method to guarantee both heat transfer efficiency and latent heat absorption. This article reports an experimental method to evaluate the natural convective heat transfer of MPCM slurry by means of setting the test rig in three angles to represent specific heating positions, i.e., θ = 0o (heated from bottom), θ = 90o (heated from side) and θ = 180o (heated from top). The thermal performances of MPCM slurry are analyzed by comparing with another two control groups: pristine PCM and MPCM particles. Results show that MPCM slurry gives the best thermal control amongst the three materials in the temperature range considered due to the thermal enhancement of natural convection, followed by pristine PCM, then MPCM particles. The surface temperature reduction of 16.3 °C is devoted by natural convection of carrying fluid in MPCM slurry, while this contribution is more pronounced (40 °C) in pristine PCM. However, the natural convection of core PCM is fully suppressed in MPCM particle. MPCM slurry with lower concentration consumes less time to reach a lower melt onset temperature at the cost of having less thermal management time.