KAl（SO4）2·12H2O-MgSO4·7H2O复合相变体系储能特性的探究

Study on Energy Storage Characteristics of KAl（SO4）2·12H2O-MgSO4·7H2O Composite Phase Change System

KAl(SO?)?·12H?O和MgSO4·7H2O作为常见的水合无机盐相变材料,具有相变潜热较大、原料较廉价易得等优点.筛选并制备出KAl(SO?)?·12H?O和MgSO4·7H2O质量配比为6:4的复合相变材料,取纯体系样品4份加入质量比(wt%)分别与1%Na2B4O7·10H2O、1%石墨粉、2% MgCl2、2% AlCl3进行混合改性.结果表明:室温条件下加入1%Na2B4O7·10H2O成核剂体系的储热特性优于加入1%石墨粉、2% MgCl2、2% AlCl3成核剂的体系,不存在过冷现象,降温过程中相变放热持续时间长;TG 曲线和 DSC 曲线表明纯体系、1%Na2B4O7·10H2O 成核剂体系二者质量损失分别为37%和42%,循环后体系DSC曲线与未循环体系趋势一致,但可看出KAl (SO?)?·12H?O-MgSO4·7H20-1% Na2B4O7·10H2O(Times>10)体系的主峰相比于KAl(SO?)?·12H?O- MgSO4·7H2O纯体系更窄,峰值温度更低,峰积分面积更小,表明循环后体系的整体相变焓降低.

KAl(SO4)2·12H2O and MgSO4·7H2O are common hydrated inorganic salt phase change materials,they have the advantages of large phase change latent heat and cheaper raw materials.In this paper,KAl(SO4)2·12H2O and MgSO4·7H2O composite phase change materials with mass ratio of 6:4 were prepared.Four pure system samples were respectively modified by 1%Na2B4O7·10H2O,1%graphite powder,2%MgCl2 or 2%AlCl3.The results showed that the heat storage characteristics of the 1%Na2B4O7·10H2O nucleating agent system at room temperature were better than those of 1%graphite powder,2%MgCl2 and 2%AlCl3 nucleating agent,there was not supercooling and its phase change exotherm time was the longest during the cooling process.The TG curve and the DSC curve showed that the mass loss of the pure system and 1%Na2B4O7·10H2O nucleator system were 37%and 42%,respectively.The DSC curve of the system after the cycle was consistent with the trend of the uncirculated system,but It was seen that the main peak of KAl(SO4)2·12H2O and MgSO4·7H2O-1%Na2B4O7·10H2O(Times>10)system was narrower than KAl(SO4)2·12H2O and MgSO4·7H2O pure system,and the peak temperature was lower,the peak integral area was smaller,indicating that the overall phase transition of the system after the cycle reduced.