Research and Application of Composite Phase-Change Materials for Energy-Saving Buildings
Date Issued
2015
Date
2015
Author(s)
Yang, Hong-Bin
Abstract
A phase change material (PCM) is also known as a material of latent thermal energy storage (LTES). When PCMs undergo phase change, it can absorb or emit large amounts of heat to store or release thermal energy. These properties can be used to control the surrounding temperature. The advantages of TES include being able to reduce the peak electricity usage of air-conditioning systems, regulate the energy use of peak and off-peak hours and delay the temperature changes on the indoor environment. In this research, PCM will be studied for building energy conservation, and the research of composite phase change materials, including the mixture designs, mechanical properties, thermal properties, thermal behavior, and the effects of the solid phase and liquid phase on the mechanical properties of concrete was also be a key focus of this research. Furthermore, analyze the application in climate of Taiwan. Based on the results of this study, the following conclusions are drawn: A higher replacement amount of PCM gave a lower specific weight of PCM-modified concrete. With increasing replacement amount, the mechanical properties such as compressive strength and elastic modulus decreased. For the drying shrinkage, as the original concrete materials were replaced by the PCM with lower strength and stiffness, the drying shrinkage also increased with the increase in amount of PCM added. And the solid-liquid phase change of PCM allows its high latent heat properties to be used. This study revealed that whether the PCM was in a solid phase or liquid phase, it also affected the mechanical properties. The PCM at liquid phase would be softer than the PCM at solid phase, lowering the compressive strength and elastic modulus, the effect of the solid-liquid phases on the drying shrinkage was less significant. Overall, the concrete containing PCM had lower strength and stiffness when compared with original concrete specimens that containing no PCM. Concrete with PCM may not suitable for use as structural elements. However, PCM is an important solution for optimizing the energy consumption in modern buildings. It can absorb or emit large amounts of heat to store or release thermal energy. These properties can be used to control the building temperatures resulting in energy saving and carbon reduction.
Subjects
Concrete containing phase-change material
phase-change material (PCM)
mechanical properties
thermal properties
solid-liquid phase of phase-change material
Type
thesis
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