水合硝酸锰复合果壳多孔碳的相变热储能研究

Phase change thermal energy storage of shell porous carbon composite manganese nitrate hydrate

开发具有较高潜热的蓄热型相变材料可以满足工程热能管理应用和建筑节能的需求,而且充分利用材料的相变潜热储能有助于缓解全球传统能源不足的问题。文章采用真空浸渍法,制备水合硝酸锰(Mn(NO_3)_2·6H_2O)/果壳多孔碳基复合相变材料,通过多种测试技术手段对其微观结构和热性能进行了分析,并研究了相变材料在多孔碳中的相变行为和热储能机制。结果表明:摩尔浓度为1.67 mol/L的复合相变材料MNCPCM-2具有均匀的Mn(NO_3)_2·6H_2O颗粒分布和较大的比表面积,其熔化相变温度T_m、相变潜热焓ΔH_1分别为27.6℃和173.6 kJ/kg,存储效率为95.7%;经过1 000次热循环,其熔化相变温度提高了13.0%,相变潜热焓降低了20.6%,最小存储效率为92.1%,且过冷度和失重较小,具有优良的相变储热和热稳定性及较好的热循环性能。

In order to meet the application of engineering thermal management and the requirements of building energy saving, it is necessary to develop a thermal storage phase change material with high latent heat. Moreover,making full use of the material phase change latent heat storage energy can help alleviate the global traditional energy shortage. The different proportions of hydrated manganese nitrate (Mn(NO 3 ) 2 ·6H 2 O)/ shell porous carbon-based composite were prepared by the vacuum immersion method. The microstructure and thermal properties of the composite phase change materials were analyzed by various testing techniques. The phase change behavior and energy storage mechanism of the phase change materials in the porous carbon were studied. The results show that the composite phase change material MNCPCM-2 with a molar concentration of 1.67 mol/L among the composite phase change materials prepared has uniform Mn(NO 3 ) 2 ·6H 2 O particle distribution and large specific surface area. The melting temperature and the latent heat enthalpy of melting phase change can reach 27.6 °C and 173.6 kJ/kg, respectively. Its storage efficiency is 95.7%. After 1 000 thermal cycles, the phase change temperature increases by 13.0%, while the phase change latent heat enthalpy decrease by 20.6%. The minimum storage efficiency is 92.1%, and the changes in supercooling and loss of weight are reduced. It is fully demonstrated that the prepared composite material maintains excellent phase change heat storage, thermal stability and good thermal cycle performance.