李洋, 张欣硕, 李馨男, 袁迪. 纳米复合相变蓄冷材料的制备及蓄冷特性分析[J]. 农业工程学报, 2022, 38(23): 284-292. DOI: 10.11975/j.issn.1002-6819.2022.23.030
    引用本文: 李洋, 张欣硕, 李馨男, 袁迪. 纳米复合相变蓄冷材料的制备及蓄冷特性分析[J]. 农业工程学报, 2022, 38(23): 284-292. DOI: 10.11975/j.issn.1002-6819.2022.23.030
    Li Yang, Zhang Xinshuo, Li Xinnan, Yuan Di. Preparation of nanocomposite phase change cold storage materials and analysis of cold storage characteristics[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(23): 284-292. DOI: 10.11975/j.issn.1002-6819.2022.23.030
    Citation: Li Yang, Zhang Xinshuo, Li Xinnan, Yuan Di. Preparation of nanocomposite phase change cold storage materials and analysis of cold storage characteristics[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(23): 284-292. DOI: 10.11975/j.issn.1002-6819.2022.23.030

    纳米复合相变蓄冷材料的制备及蓄冷特性分析

    Preparation of nanocomposite phase change cold storage materials and analysis of cold storage characteristics

    • 摘要: 针对生鲜冷链物流领域冷藏运输温度要求,该研究通过差示扫描量热仪(Differential Scanning Calorimeter, DSC)对甘氨酸、山梨醇、甘露醇、氯化钾进行筛选,经优化后配置出主储能为0.6mol/L甘氨酸+0.1mol/L山梨醇(命名为TA2),以此体系为基液添加纳米二氧化钛和纳米氧化铝,并添加高吸水性树脂(Super Absorbent Polymer, SAP)对防泄漏现象进行优化,探究添加纳米粒子后复合相变蓄冷材料的相变潜热和热循环稳定性。将该复合材料应用于自制保温箱,以水晶梨为试验对象进行了蓄冷箱保冷特性试验,对比蓄冷保温箱载货与空载情况下箱内各点的温度变化,综合考虑蓄冷保温箱内蓄冷剂侧面布置和顶层布置加侧面布置这两种摆放方式对保冷性能的影响。结果显示,添加质量分数为0.5%的纳米二氧化钛粒子可使基液的导热系数达到最大值,经优化的最终材料为TA2+0.5%TiO2+0.25%SAP,相变潜热为294.57 J/g,Onset温度为-5.8 ℃,经过200次循环试验,复合材料热性能稳定。蓄冷剂以侧布加顶布的摆放方式下的大部分箱内空间可在0~5 ℃保持480 min,温度场更均匀,利于保持生鲜产品新鲜度。研究结果可为相变材料在生鲜冷链物流中的研制及应用提供参考。

       

      Abstract: Here, one kind of cheap cold storage material was prepared to fully meet the requirements of temperature in the cold chain logistics field of fresh refrigerated transport. Firstly, the aqueous solutions of different concentrations were configured to dividually mix the solutions of the energy storage agents, including glycine, sorbitol, mannitol, and potassium chloride. Differential Scanning Calorimetry (DSC) was then used to determine the latent heat of phase transition and onset temperature at different concentrations. The combination of glycine and sorbitol, potassium chloride, and mannitol was finally selected to obtain two kinds of combination schemes. The first one was using 0.1 mol/L sorbitol aqueous solution as the compound of Onset temperature adjustment. According to the volume ratio of 1:1, 0.8, 0.6, 0.4, 0.2, and 0.1 mol/L glycine aqueous solution (named composite solution A1-A5) were added, respectively. In the other compound scheme, 0.6 mol/L mannitol aqueous solution was used as the compound agent to adjust the temperature of Onset. According to the volume ratio of 1:1, 0.8, 0.6, 0.2, 0.1, and 0.05 mol/L potassium chloride aqueous solution (named composite solution B1-B5) were added, respectively. The undercooling test was performed on the composite solution A1-A5, indicating the better performance of composite solution A2. The thermal properties of compound solutions A2 and B1-B5 were determined by DSC. The composite solution B1-B5 was prone to undercooling. As such, the composite liquid A2 was chosen as the main energy storage agent of the final composite phase change cold storage material. Finally, the mixed solution A2:0.6 mol/L glycine +0.1 mol/L sorbitol was determined as the main coolant, which was named TA2. Then, the nano-sized titanium dioxide and alumina were added to the system TA2 as the base liquid, and the Super Absorbent Polymer (SAP) was added to optimize the leakage prevention phenomenon, in order to explore the latent heat and thermal cycle stability of composite phase change cold storage materials after the addition of nanoparticles. It was found that the addition of 0.5% nano-TiO2 presented the best effect on the supercooling degree and thermal conductivity of cold storage materials. In view of the leakage of the cold storage bag, 0.25% SAP was added to effectively prevent leakage. The optimized nanophase change cold storage material was TA2+0.5%TiO2+0.25%SAP, where the latent heat was 294.57 J/g, and the initial temperature was -5.8℃. The temperature zone fully met the performance requirements of fresh refrigerated transport. The 200-cycle tests show that the new material can be expected to serve as excellent stability in practical cold chain logistics. The nano-composite phase change cold storage material has been applied to the domestic incubator. The cooling properties of the incubator were also tested with the crystal pear as the test object. In addition, the temperature changes of each point were compared in the cold storage incubator under loaded and empty conditions, considering the influence of side and top+side arrangement on the cooling performance of the cold storage incubator. The results show that the average temperature in most of the boxes under the arrangement of side and top cloth, which can be kept at 0-5 ℃ for 480 min. The temperature field was more uniform to maintain the freshness of fresh products.

       

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