Preparation of diatomite paraffin composite phase change coating and its simulation application in building wall

A new phase change heat storage coating is prepared in this study, which can regulate indoor temperature. The composite phase change material (D/PCM) with modified diatomite and paraffin was prepared by the porous material adsorption method. D/PCM and coatings were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and cycle leakage ratio. The SEM results showed that diatomite modified by high-temperature expansion and acidification has a better adsorption capacity. D/PCM and C-D/PCM (heat storage coatings with D/PCM) have nearly no leakage and still show good thermal stability after 500 thermal cycles. In addition, the heat transfer process in a physical model of a reinforced concrete wall was simulated based on hourly variations in summer temperatures in Xi'an, China. The results show that C-D/PCM with a phase change temperature of 26–28 °C and a thickness of 5 mm provides greater heat storage capacity, good temperature regulation and energy savings within a reasonable thickness range in summer. The selected PCM coatings have a small temperature fluctuation (2.54 °C) and a high phase change utilization ratio (75 %), which can reduce the wall cooling load by 18.67 % in summer and save energy.