Abstract
A new class of magnetic phase-change microencapsulated-nanoparticles fluid (MPCMNF) was produced via dispersing magnetic capsules into deionized water with surfactant. The microcapsules were prepared by in-situ polymerization method to encase phase-change paraffin (PW) into CaCO3 shell with magnetic Fe3O4 nanoparticles. The microstructure, and the thermal and magnetic properties of the magnetic capsules were experimentally characterized. It is found that the PW@CaCO3/0.8%Fe3O4 (i.e., 0.8 % mass ratio of Fe3O4 to PW) exhibits the highest thermal performance and encapsulation efficiency among the four mass fractions evaluated, reaching enthalpy of 80.2 ± 2.6 J/g, thermal conductivity of 0.998 ± 0.017 W/(m·K), and encapsulation efficiency of 56.2 ± 1.1 %. The saturation magnetization of the PW@CaCO3/0.8%Fe3O4 is 1.032 ± 0.021 emu/g, indicating an excellent magnetic property. The thermal conductivity, magnetic property, viscosity and density of the MPCMNF with different concentrations of PW@CaCO3/0.8%Fe3O4 have been measured. Results show that the MPCMNF has a dual magnetic and thermal energy storage property, scouting particular applications in fluid flow, heat transfer, and energy storage.