摘要
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)_2·6 H_2O)/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)_2·6 H_2O 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.
引文
[1] 丁兴江,章学来,徐笑锋,等.相变储能技术在现代温室工程加热系统中的应用[J].能源研究与应用,2018(6):34-38.
[2] Ibrahim N I, Al-Sulaiman F A, Rahman S A, et al.Heat transfer enhancement of phase change materials for thermal energy storage applications: A critical review[J].Renewable and Sustainable Energy Reviews,2017,74:26-50.
[3] 蔺瑞山,田斌守,邵继新,等.相变储热在太阳能采暖中的应用研究[J].节能技术,2018,36(5):447-475.
[4] 朱传辉,李保国.相变蓄热材料应用于太阳能采暖的研究现状[J].中国材料进展,2017,36(3):236-240.
[5] 黄婷,罗奇,蒋思成.相变材料在建筑节能中的应用及其实验研究[J].新型建筑材料,2017(11):96-100.
[6] 李彦山,汪树军,史全,等.储能相变材料制备方法研究进展[J].功能材料,2015,46(6):6008-6014, 6019.
[7] Pielichowska K, Pielichowski K.Phase change materials for thermal energy storage[J]. Progress in Materials Science,2014,65:67-123.
[8] 张仁元,谢致薇,柯观生,等.相变材料与相变储能技术[M].北京:科学出版社,2009.
[9] Hassabo A G, Mohamed A L, Wang H L, et al.Metal salts rented in silica microcapsules as inorganic phase change materials for textile usage[J].Inorgainc Chemistry an Indian Journal,2015,10(2):59-65.
[10] 何小芳,吴永豪,王月明,等.相变储能材料的研究进展[J].化工新型材料,2014,42(12):27-29.
[11] Mohamed S A, Al-Sulaiman F A, Ibrahim N I, et al.A review on current status and challenges of inorganic phase change[J].Renewable and Sustainable Energy Reviews,2018,92:254-271.
[12] 李凤艳,王鹏,袁亚东,等.相变温度为室温的Na_2SO_4·10H_2O相变储热材料的制备研究[J].合成材料老化与应用,2015,44(1):39-41, 46.
[13] 谷海明.相变储能材料Mn(NO_3)_2·6H_2O的稳定与储热性能研究[D].昆明:昆明理工大学,2013.
[14] Mochida K T, Domanski S R, Rebow M.Thermal characteristics of Manganese(II)nitrate hexahydrate as a phase change material for cooling systems[J].Applied Thermal Engineering,2003,23:229-241.
[15] Shomate C H, Young F.Heats of formation of solid and liquid Mn(NO_3)_2·6H_2O[J]. Journal of America Chemical Society,1944,66(5):771-773.
[16] Safari A, Saidur R, Sulaiman F A, et al.A review on supercooling of Phase Change Materials in thermal energy storage systems[J].Renewable and Sustainable Energy Reviews,2017,70:905-919.
[17] 马颖,刘益才,朱晓涵,等.环境温度对无机水合盐相变材料过冷行为的影响机理[J].中南大学学报(自然科学版),2017,48(7):1930-1935.
[18] 朱教群,宋轶,周卫兵,等.基于碳材料的有机复合相变材料导热增强研究进展[J].储能科学与技术,2017,36(2):213-222.
[19] Zhang D, Tian S L, Xiao D Y.Experimental study on the phase change behavior of phase change material confined in pores[J].Solar Energy,2007,81(5):653-660.
[20] 张源,戴晓丽.相变温度对相变蓄能墙体热性能影响特性[J].江苏大学学报(自然科学版),2018,39(6):671-677.
[21] Li M, Chen M R, Wu Z S, et al.Carbon nanotube grafted with polyalcohol and its influence on the thermal conductivity of phase change material[J].Energy Conversion and Management,2014,83:325-329.
[22] 祝丹婷,钱静,蔡蓉.混合水合盐作为储热相变材料的热物性能研究[J].包装工程,2015,36(1):65-69.
[23] 张森景,李青达,张文杰,等.温室墙体用蓄热新材料的发展J][J].陶瓷学报,2018,39(5):529-538.
[24] 赵有璟,时历杰,康为清,等.相变温度可调的无机混盐体系相变储能材料[J].材料科学与工程学报,2014,32(1):79-84.
[25] Mills A, Farid M, Selman J R, et al.Thermal conductivity enhancement of phase change materials using a graphite matrix[J].Applied Thermal Engineering,2006,26(14/15):1652-1661.
[26] Yortsos Y C, Stubos A K.Phase change in porous media[J]. Current Opinion in Colloid and Interface Science,2001,6(3):208-216.
[27] 毛前军,刘宁,彭丽.一种新型复合相变蓄热材料的制备与表征[J].可再生能源,2018,36(10):1574-1580.
[28] 王刚,吴志根.水溶液法制备硝酸盐/膨胀石墨粉复合相变材料的实验研究[J].材料导报B(研究篇),2015,29(3):60-64.
[29] Zhong L M, Zhang X W, Luan Y, et al.Preparation and thermal properties of porous heterogeneous composite phase change materials based on molten salts/expanded graphite[J].Solar Energy,2014,107:63-73.
[30] Zhou D, Zhao C Y.Experimental investigations on heat transfer in phase change materials (PCMs) embedded in porous materials[J].Applied Thermal Engineering,2011,31(5, SI):970-977.
[31] Wang C Y, Feng L L, Li W, et al.Shape-stabilized phase change materials based on polyethyleneglycol/porous Carbon composite:The influence of the pore structure of the Carbon materials[J].Solar Energy Materials & Solar Cells,2012,105:21-26.
[32] Zhang X G, Yin Z Y, Meng D Z, et al.Shape-stabilized composite phase change materials with high thermalconductivity based on stearic acid and modified expanded vermiculite[J].Renewable Energy,2017,112:113-123.
[33] Wang C Y, Feng L L, Li W, et al.Shape-stabilized phase change materials based on polyethylene glycol/porous Carbon composite: The influence of the pore structure of the Carbon materials[J].Solar Energy Materials and Solar Cells,2012,105:21-26.
[34] Liu Y S, Yang Y Z.Form-stable phase change material based on Na_2CO_3 ·10H_2O-Na_2HPO_4·12H_2O eutectic hydrated salt/expanded graphite oxide composite: The influence of chemical structures of expanded graphite oxide[J].Renewable Energy,2018,115:734-740.
[35] Liu M, Bell S, Segarra M, et al.A eutectic salt high temperature phase change material: Thermal stability and corrosion of SS316 with respect to thermal cycling[J].Solar Energy Materials and Solar Cells,2017,170:1-7.