Thermal Characteristics of Eutectic Mixtures of Fatty Acids as Phase Change Material
Rozanna Dewi, (2005) Thermal Characteristics of Eutectic Mixtures of Fatty Acids as Phase Change Material. Masters thesis, Universiti Putra Malaysia.
Latent heat storage in phase change material (PCM) is one of the efficient ways of storing thermal energy. In latent heat storage, energy is stored in a small mass/volume with a narrow temperature transition between melting and solidifying. This study aims to investigate the effect of using eutectic mixtures of fatty acids as PCM in building material such as gypsum board, palm-based and petrochemical-based polyurethane. Gypsum is widely used in construction industry due to its low cost. It is considered as a good supporting material for thermal energy storage since it has 41% air voids. The choice of polyurethane (PU) is made because of its increase uses in the construction industry. There were four type of eutectic mixture of fatty acids used in this work, which are lauric-stearic acids (75.5:24.5 w/w %), myristic-palmitic acids (58:42 w/w %), palmitic-stearic acids (64.2:35.8 w/w %) and capric – lauric acids (65:35 w/w %). Differential Scanning Calorimetry (DSC) analysis showed that binary mixture of fatty acid form eutectic mixture that have a definite melting/solidification points with a sharp peak and no additional hump. The latent heat for the mixtures is considered high compared to other PCM. DSC analysis showed that the thermal characteristics such as melting point, melting ranges, solidification point and solidification ranges of fatty acid impregnated in host material, are identical to fatty acid before impregnation. The latent heat of PCM was higher after impregnated in host material as an effort is needed to break the internal bond between PCM and host material. SEM analysis demonstrated that pore structure of host material was not influenced by the immersion process. Indeed, the hardness of host material remained as original.
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