Study on Energy-Storing Building Materials Made of Paraffin/Montmorillonite Composites

Abstract

Phase change materials (PCM) are promising in the application for reducing building energy consumptions and increasing thermal comfort. However, PCM have not been used as building materials extensively. A major technical hindrance for the applications of PCM in building materials is the packaging of PCM. The strategies for the packaging of PCM in building materials reported in the previous studies were mostly unsatisfactory because of the disadvantages such as complex proccesses, high cost or poor packing effectiveness, etc. This study presented a novel simple and low-cost way to make energy-saving building materials with PCM. In this study, a composite containing PCM was developed with montmorillonite (MMT) and paraffin via a simple and low-cost route. Through the selection of appropriate raw materials and with the vigorously mixing using a high-shear mixer, the PCM/MMT composites were prepared simply. The thermal properties of the PCM/MMT composites were investigated by differential scanning calorimetry (DSC). Based on the thermal properties and packing effectiveness the weight ratio of PCM: MMT = 5:4 was determined as the appropriate composition of the PCM/MMT composites. As compared with the PCM composites made of organically modified MMT, the PCM/MMT composites prepared in this study exhibited higher compression strength. The thermal conductive performance of the wallboards made of the PCM/MMT composites and the ordinary wallboards was simulated through numerical simulation. The experimental systems were also set up for testing the energy-saving characteristic of the building materials containing the PCM/MMT composites under both laboratorial conditions and natural outdoor conditions The numerical simulation as well as the experimental results indicated that the wallboard made of the PCM/MMT composite could effectively reduce the temperature fluctuation and would be favorable for keeping room in a comfortable temperature range. Hence the PCM/MMT composites might be promising for developing high-performance thermal regulating building materials with low-cost.