Abstract:
Structural materials provide one of the best option for the rapid development of energy saving materials. Phase change materials (PCMs) are the latent thermal storage materials that has the capacity to store large amount of thermal energy during its phase change from solid to liquid and vice versa. In this study, focus was given to the preparation of macro encapsulated phase change materials (ME-PCMs) for the development of thermal energy storage light weight aggregate concrete (LWAC) with appreciable structural properties, and capable of storing thermal energy within the human thermal comfort zone. Paraffin used in this research was a mixture of Ethyl laurate and 2-Hydroxybenzyl alcohol mixed in a ratio of 1:1, was impregnated under vacuum into the porous LWAs for the development of ME-PCMs. A paste of epoxy, graphite powder and Nano-silica particles was used for encapsulation of impregnated paraffin loaded LWA. To ensure proper dispersion of graphite powder and Nano-silica fumes into epoxy mixture probe sonicator was used. The compressive strength, microstructure, thermal properties, thermal stability, chemical compatibility and thermal reliability were investigated by compressive strength machine (CSM), Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC), Thermo gravimetric analyzer (TGA), Fourier transformation infrared spectrum analysis (FT-IR) and thermal cycler test. From the in depth investigation of test result, it was concluded, that the maximum paraffin absorption of LWA under vacuum was found to be 16.60%, the compressive strength of LWAC using ME-PCMs at 28 days was more than 15Mpa which showed that developed ME-PCM is a promising candidate in structural application. From the TGA analysis, it was determined that developed ME-PCM was found to be thermally stable. Thermal cycler test revealed that, the ME-PCM was found to be chemically compatible and thermally reliable. Moreover, from the DSC curves, it was determined that the melting and freezing point of ME-PCMs was 19.99°C and 32.27°C respectively, with an energy storage capacity of 12.6 J/g of the ME-PCMs, concluding that the developed material is in human thermal comfort zone (20°C-32°C). From the results, it can be concluded that ME-PCMs can be used for the development of thermal energy storage concrete in sustainable construction.
