物理法制备芒硝基复合相变材料及其性能研究

Preparation and Properties of Glauber's Salt-based Composites Phase Change Materials by Physical Method

以芒硝(Na_2SO_4·10H_2O)为主相变材料,采用物理共混法,筛选出合适添加辅助材料组成多元混盐体系,制备出相变温度在25℃左右的Na_2SO_4·10H_2O基复合相变材料,研究了原料配比对相变材料相变温度和相变潜热的影响。通过热重分析、T-history曲线、差示扫描量热法等表征了制备的芒硝基相变储能材料性质。结果表明:二元相变材料相变温度随着Na_2CO_3·10H_2O增加而先降低后增大;相变材料相变潜热密度基本不变。三元相变材料相变温度随着Na Cl、KCl、NH_4Cl量增加相变温度降低;相变材料相变潜热密度相比于二元体系有所减小,且在一定范围内随着成核剂硼砂含量的增加该体系相变潜热密度基本保持不变,过冷度有明显下降。当Na_2SO_4·10H_2O量为86.4%、Na_2CO_3·10H_2O量为9.6%、NaCl量为4%,对该配方改性添加3%的硼砂和0.1%的羧甲基纤维素钠时,此相变材料的相变温度为24.6℃,过冷度为0.3℃,相变潜热密度为179.6 J/g。

Glauber 's salt( Na_2SO_4·10H_2O) based composite phase change energy storage materials( composite PCMs) were prepared by physical blending method. To effectively control phase change melting temperature point in the near 25 ℃ and maintaining high phase change melting enthalpy,adding melting point regulator agents、nucleation agents and thickening agents. Samples were tested by TG,T-history and DSC. The results show that the glauber's salt based binary composite PCMs,with the quality of glauber's salt increased,phase change melting temperature point first increases then decreases,phase change melting enthalpy keep essentially unchang. the glauber's salt based temary composite PCMs,with the quality of melting point regulator agents( Na Cl,KCl,NH_4Cl) increase,phase change melting temperature point decrease,phase change melting enthalpy less than the binary. With in a certain range,as nucleation agents borax increase,melting temperature point keep essentially unchanged,while undercooling temperature have significantly decrease.when Na_2SO_4·10H_2O 86. 4%,Na_2CO_3·10H_2O 9. 6%,NaCl 4% adding 3% borax and 0. 1% sodium tylose,undercooling temperature decreases and the phase transformation temperature of phase change materials suitable for use in greenhouses,phase change melting temperature point is 24. 6 ℃,undercooling temperatureis 0. 3 ℃,phase change melting enthalpy is 179. 6 J / g.