季戊四醇与三羟甲基乙烷相变材料蓄热性能研究

EXPERIMENTAL RESEARCH OF THE PHASE-CHANGE HEAT STORAGE MATERIALS PENTAERYTHROTOL AND TRIMETHYLOLETHANE

对一类可用于太阳能中温蓄热的有机相变材料性能进行实验分析。相变蓄热材料具有储热密度大、温度波动小等优点,但也存在导热系数低、过冷度较大的问题,对相变材料进行复合,能有效改善其相变特性与导热性能。利用高温融化-混合的方法制备季戊四醇(PE)与三羟甲基乙烷(PG)的混合材料,使用DSC仪器分析相变温度与相变潜热,同时研究不同形核剂对混合材料的相变温度、过冷度的影响。利用压制成型—融化吸附—冷却的方法制备膨胀石墨与PE、PG的复合相变材料,用激光导热系数测试仪测试复合相变材料的导热性能。结果表明,PE与PG混合相变材料的相变温度区间基本在25℃以上,过冷度约15℃,膨胀石墨作为形核剂,使过冷度有一定减小。增加复合相变材料中膨胀石墨的含量能提高材料各个方向的导热系数。

Experimental research on a kind of phase-change heat storage materials appropriate for the solar thermal storage at middle temperature level was done to analyze the thermal property. The advantages of the material are its high density of heat storage and little fluctuation of temperature, while the defect is the low thermal conductivity and large undercooling temperature. Compositing several phase change materials could enhance the heat-conducting property and improve the phase change characteristic. The hybrid material of Pentaerythrotol （PE） and trimethylolethane （PG） was prepared by the melting-mixing method. Using the DSC device, the phase-transition temperature and the latent heat of phase change were tested, and the influences the nucleating agents bring to the material＇ s phase-transition temperature and the undercooling temperature were revealed. Using the compacting-melting-absorbing-cooling method, the composite material of PE, PG and expanded graphite were made, the thermal conductivity of which is tested by the laser thermal conductivity tester. The results showed that the phase-transition temperature regions are above 25 ℃ and the undercooling temperature is about 15 ℃ which will go down slightly when expanded graphite acts as the nucleating agents. And rising the content of the expanded graphite in the composite material will increase the heat conductivity coefficient in different directions.