| Phase change material(PCM) is a kind of functional material that can change its physical state in a certain range of temperature, it absorbs and releases large amounts of heat when material changes during different state along with thermal energy storge occurs, PCM has great advantages of environmental friendly and renewable.The paper has summarized the research progress of phase change materials at home and abroad and the development trend, its classification and application in various fields. The melting point and enthalpy of fusion change rules about alkane(carbon number 13-36), alcohols(carbon number 13-18), carboxylic acid(carbon number 10-20), ethers(carbon number 24-36) were discussed. The enthalpy of fusion of nicotinic acid, isonicotinic acid, m-aminobenzoic acid, p-nitrotoluene, p-hydroxy benzoic acid were calculated by using the group contribution and measured by DSC, the calculated value and experimental measurements value, literature reference value were compared and analyzed. The article also studied the enthalpy of fusion of isonicotinic acid alone, the result of DSC showed isonicotinic acid releases heat 1040 J/g at the melting temperature 288.9 oC, the relative error between experimental and the literature reference value is 5.24 %. TG showed isonicotinic acid decomposed completely at 277.4oC, but the thermal cracking test showed that isonicotinic acid did not split at 600 oC. Therefore, the value provided by literature reference is only the sublimation enthalpy of isonicotinic acid. The paper also investigated the medium and high temperature phase change materials in the end, illustated the melting point temperature and enthalpy of fusion of a portion of the medium temperature phase change materials. Several kinds of high temperature phase change materials were also introduced, and melting point and enthalpy of fusion of the carbonate, chlorate, nitrate, fluoride salt and other high temperature phase change materials were listed. |
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