Preparation and evaluation of a novel solar storage material: Microencapsulated paraffin

Abstract

Microencapsulated paraffin, a novel solar storage material, was prepared by complex coacervation technique and its performance was evaluated in terms of encapsulation ratio, hydrophilicity, energy storage capacity, and size distribution. The experiments were designed, based on surface response method, to optimise the processing conditions. The sizes of the microencapsulated paraffin particle were 50-100 μm. For an emulsification time of 10 min and the addition of 6-8ml (2.9-3.8% w/w) of formaldehyde (HCHO), the paraffin encapsulation ratio was found higher in different ratio of paraffin wax to coating (menu). It was also found that a higher coating to paraffin ratio leads to a higher paraffin encapsulation ratio. The hydrophilicity value of microencapsulated paraffin depended mainly on the ratio of paraffin to coating. The higher the ratio, the lower was its product hydrophilicity, in the same ratio of paraffin wax to coating, the higher concentration of HCHO led to a lower hydrophilicity of the product. The microencapsulated paraffin has shown large energy storage and release capacity (20-90 J/g) during its phase change depending on different ratios of paraffin wax to coating.