Development of Encapsulated Shea Butter as Bio-Based Phase change Material for Thermal Storage Application

In this study, unrefined Shea butter is studied as a low-cost biological phase change materials for medium thermal storage applications. The phase change behavior of the Shea butter was investigated using Differential Scanning Calorimetry (DSC). Charging/discharging experiments were carried out to investigate the effect of Heat Transfer Fluid inlet temperature using water (HTF=45°C) with time, in an experimental rig set up consisting of encapsulated Shea butter. A 2-D axisymmetric model was used to model its thermal transient behavior using a Computational Fluid Dynamics (C.F.D) software package. In the DSC results of Shea butter, phase change temperature onset = 31.25°C, end set = 40.2°C, latent heat = 50.34 J/g. Total charging/discharging and melting time of Shea butter was highest at 110/145min at 2 L/min flow rate, and lowest at 70min 6 L/min. However, efficiency was observed to be highest at 68.5% at 6 L/min, and lowest with 63% at 2 L/min. Computational fluid dynamics results are obtained in 2-D temperature-velocity streamlines and 3-D solid-liquid phase change moving boundary of the encapsulated Shea butter with time. These streamlines showed a time dependent heat transfer process during charging of the Shea butter capsules in the experimental rig. The results were used to validate experimental results at an absolute percentage error of 4.7%.