Preparation and Properties of a Composite Phase Change Energy Storage Gypsum Board Based on Capric Acid-Paraffin/Expanded Graphite

[Image: see text] Energy has become the key material basis of social development. In this work, liquid capric acid-paraffin was evenly adsorbed in the pore structure of expanded graphite (EG) by a physical adsorption method, and the new composite phase change material of capric acid-paraffin/expanded graphite (CA-P/EG) was prepared. The Fourier transform infrared (FT-IR) curves of CA-P/EG composites did not change after 1000 cycles, and there was no new characteristic absorption peak, indicating that CA-P/EG composites have good chemical stability. The results showed that the optimum content of CA-P/EG in a phase change energy storage gypsum board was 20%, and the wet bending strength and compressive strength were 2.42 and 6.45 MPa, respectively. The water absorption was 16.37%, and the apparent density was 1.410 g/cm(3). In addition, the melting and freezing temperatures were 26.40 and 23.10 °C, and the latent heats of melting and freezing were 27.20 and 25.69 J/g, respectively. It was found that the gypsum board has excellent thermal stability after 400 times of melting–freezing cycling and that the heat storage capacity increases with the increase of the CA-P/EG content and the thickness of the gypsum board.