Microencapsulated PCM thermal-energy storage system

Abstract

The application of phase-change materials (PCM) for solar thermal-energy storage capacities has received considerable attention in recent years due to their large storage capacity and isothermal nature of the storage process. This study deals with the preparation and characterization of encapsulated paraffin-wax. Encapsulated paraffin particles were prepared by complex coacervation as well as spray-drying methods. The influence of different parameters on the characteristics and performance of a microencapsulated PCM in terms of encapsulation efficiency, and energy storage and release capacity has been investigated. The distribution of particle size and the morphology of microencapsulated PCM were analyzed by a scanning electron microscope (SEM). In the coacervation method, the optimum homogenizing time is 10 min and the amount of cross-linking agent is 6-8 ml. Results obtained from a differential scanning calorimeter (DSC) show that microcapsules prepared either by coacervation or the spray-drying method have a thermal energy storage/release capacity of about 145-240 J/g. Hence, encapsulated paraffin wax shows a good potential as a solar-energy storage material. © 2002 Elsevier Science Ltd. All rights reserved.