One of the ways to reduce building energy is to actively release or store the thermal energy through phase change materials (PCMs) to use heat energy efficiently. PCMs have the major drawback of leaking during the solid-liquid phase transition. Therefore, PCMs must be applied to buildings through phase stabilization. Expanded vermiculite (EV) and expanded perlite (EP) are porous nanoclay materials possessing excellent properties as containers for PCMs. The applied PCM is n-octadecane, which belongs to the organic paraffin series, is thermally stable, and has high latent heat capacity. Shape-stabilized PCM (SSPCM) is stabilized by the vacuum impregnation method by physical bonding only, without chemical reaction. The thermal properties of the prepared SSPCM are analyzed by DSC, TGA, TCi, and enthalpy calculation. The RC-SSPCMs panel is developed using red clay (RC), an eco-friendly building material. The thermal performance of the manufactured panels is analyzed by the climate cycling test, which considers the daily temperature behavior. In the analysis of the thermal performance, the peak temperature reduced by up to 1.6 °C during the phase transition of RC/EP-SSPCMs (P10), the time-lag effect in the phase change transition of RC/EP-SSPCMs (P10) occurred for up to 1.33 h.
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In order to apply a PCM to a building, the shape of the solid-liquid phase change must be stable. For this purpose, some researchers have studied the shape stabilization techniques of PCMs; these techniques can be roughly divided into three kinds?microencapsulation using a polymer shell , macroencapsulation using polyvinyl chloride [11,12] and the shape-stabilization method, which is impregnation with a PCM in a vacuum state using a porous material. Jeong et al. developed SSPCM using paraffinic n-octadecane, fatty acid beeswax, and exfoliated graphite nanoplatelets (xGnP) with high thermal conductivity as a containing material. They confirmed that the latent heat of n-octadecane and the latent heat of beeswax were exerted at the same time, and the thermal conductivity was improved to 0.6?W/mK according to the SSPCM content . Lee et al. Developed a 3-step filleterd vacuum impregnation method that improved the vacuum impregnation method by mass-production of SSPCM. Paraffin-based n-octadecane was used and the supporting materials of C-300, C-500, activated carbon (AC), expanded graphite (EG) and exfoliated graphite nanoplatelets (xGnP) were used . Kong et al. developed SSPCM impregnated paraffin with expanded perlite and fabricated PCM panels using SSPCM for evaluation of thermal performance. The changing thermal performance was evaluated by applying PCM to cubes with a size of 1?m3. In case of the PCM applied test room, the temperature fluctuation decreased and the peak temperature decreased [15,16]. When the PCM is applied to a building, it has a high energy density due to the latent heat storage effect in the phase change, which causes a time-lag effect due to the thermal inertial increase or peak temperature reduction .This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2019R1A2C4100284). This research was supported by the Yonsei University Research Fund of 2018 (2018-22-0193).
This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2019R1A2C4100284 ). This research was supported by the Yonsei University Research Fund of 2018 ( 2018-22-0193 ).
© 2019 Elsevier Ltd
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Civil and Structural Engineering
- Geography, Planning and Development
- Building and Construction