摘要
针对传统太阳能供热系统储热水箱体积大、储热密度低、温度不恒定、热量损失大等缺点,开展以Ba(OH)_(2)·8H_(2)O为基体的相变蓄热/供热实验研究。在油封环境下,对Ba(OH)_(2)·8H_(2)O放热过程出现的过冷现象,选取了同晶型成核剂Sr(OH)_(2)·8H_(2)O、非同晶型成核剂Na_(2)B_(4)O_(7)·10H_(2)O;对Ba(OH)_(2)·8H_(2)O的相分层现象,选取增稠剂羧甲基纤维素、增稠剂明胶。实验表明,油封环境下向Ba(OH)_(2)·8H_(2)O中添加质量分数为3%的Na_(2)B_(4)O_(7)·10H_(2)O和质量分数为1%的羧甲基纤维素能够较好改善Ba(OH)_(2)·8H_(2)O的过冷现象和相分层。以该研究为基础,制备97 kg Ba(OH)_(2)·8H_(2)O复合相变材料,搭建相变蓄热/供热实验平台。蓄热实验中,温度曲线呈现明确的三阶段性,蓄热总时长1185 min,相变过程首先从底部开始,并逐步向上蔓延。70℃以下蓄热时长为185 min,温升率高,蓄热量少。70~80℃蓄热时长为965min,温升率低,蓄热量大;80~84℃蓄热时长为35min,温升率高,蓄热量少。供热实验无过冷现象,供热总时长602 min,A、B、C三测点温度平缓下降。散热器供水温度范围为60~74℃,回水温度范围为53~65℃,供回水温度符合实际工程要求。供热实验表明Ba(OH)_(2)·8H_(2)O复合相变材料在应用于蓄热供热时具有较好应用价值。
In view of the shortcomings of traditional solar heating systems,such as large volume of hot water storage tanks,low heat storage density,nonconstant temperature and large heat loss,experimental research on phase change heat storage/heating with Ba(OH)_(2)·8H_(2)O as the substrate was carried out.Under the oil sealing environment,the homocrystalline nucleating agent Sr(OH)_(2)·8H_(2)O and the nonhomocrystalline nucleating agent Na_(2)B_(4)O_(7)·10H_(2)O were selected for the overcooling phenomenon in the exothermic process of Ba(OH)_(2)·8H_(2)O,while the thickening agent gelatin and the thickening agent carboxymethylcellulose were selected for the phase delamination phenomenon of Ba(OH)_(2)·8H_(2)O.The experiments showed that the addition of Na_(2)B_(4)O_(7)·10H_(2)O with a mass fraction of 3%and carboxymethyl cellulose with a mass fraction of 1%to Ba(OH)_(2)·8H_(2)O could better improve the supercooling phenomenon and phase delamination of Ba(OH)_(2)·8H_(2)O.Based on this study,97 kg of Ba(OH)_(2)·8H_(2)O composite phase change material was prepared to build the experimental platform for phase change heat storage/supply.In the heat storage experiment,the temperature and time curves showed a clear three-phase nature,with the length of the heat storage being 1185 min,and the phase change process starts from the bottom and gradually spreads upward.The length of the heat storage below 70 oC was 185 min,with a high rate of temperature rise and a small amount of heat storage.The length of the heat storage between 70 oC and 80 oC was 965 min,with a low rate of temperature rise and a large amount of heat storage.The length of the heat storage between 80 oC and 84 oC was 35 min,with a high rate of temperature rise and a less amount of heat storage.There was no overcooling phenomenon during the heating experiments,the total length of heating was 602 min,the temperature of measuring points A,B and C dropped gently.The radiator's supply water temperature ranged from 60℃ to 74℃,and the return water temperature ranged from 53℃ to 65 ℃,supply and return water temperature in line with the actual project requirements.The heating experiment showed that Ba(OH)_(2)·8H_(2)O composite phase change material had good application value when applied to heat storage and heating.
作者
张一澍
张文庆
ZHANG Yishu;ZHANG Wenqing(School of New Energy and Power Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)
出处
《新能源进展》
CSCD
北大核心
2024年第3期353-360,共8页
Advances in New and Renewable Energy
基金
甘肃省科技计划项目(21JR7RA329)
