Research on the low-temperature waste heat storage performance of a novel microencapsulated phase change material with a double-shell encapsulation of hexadecylamine

Phase change materials (PCMs) have the advantages of high energy storage density and the temperature can be kept stable when the phase change process occurs, so they can be widely applied to the recovery of industrial waste heat. In this paper, hexadecylamine (HDA) was selected as PCMs, polystyrene (PS) and calcium carbonate (CaCO3) as wall materials, and PS/CaCO3/HDA microencapsulated phase change materials (MEPCMs) were prepared by ultrasonic emulsification. Then the prepared PCMs were characterized and their properties were tested by using transmission electron microscopy, scanning electron microscopy, X-ray diffraction analyzer, X-ray photoelectron spectrometer, Fourier infrared spectrometer, thermogravimetry, differential scanning calorimetry and other characterization methods. The results showed that PS/CaCO3/HDA MEPCMs with microcapsule structure were successfully prepared with a diameter of about 1.5 μm. The thermal conductivity of PS/ CaCO3/HDA MEPCMs was 0.491 W/(m·K), which was 3.41 times of the thermal conductivity of pure HDA. The highest latent heat of PS/CaCO3/HDA MEPCMs was 33.96 kJ/kg, and no leakage problems occurred. The above results indicate that PS/CaCO3/HDA MEPCMs have good stability and high thermal conductivity, and they have good thermal storage performance at low temperatures.