With the rapid development of cold chain logistics, there is a growing demand for refrigerated transportation equipment for low-temperature products, such as fresh products, chemical supplies and medical vaccines. For some products with low transport temperatures, phase change materials (PCMs) from −10 C to −40 °C are still to be developed. This paper focuses on the development of a low phase transition temperature nanofluid phase change materials (NFPCMs) with excellent thermodynamic properties, simple preparation method and low cost. 23 wt% MgCl₂ eutectic solution was used as phase change material in the NFPCMs, in which Multi-walled carbon nanotubes (MWCNTs) and nucleating agents play a supportive role to reduce supercooling degree. At that, the addition of MWCNTs increases the thermal conductivity and thickener xanthan gum (XG) can prevent phase separation and agglomeration. The NFPCM with 1 wt% MWCNTs has a phase transition temperature of −34.54 °C, a phase transition enthalpy of 146.9 kJ kg⁻¹, and thermal conductivity of 0.5344 W (m k)⁻¹. Also, under the synergistic action of MWCNTs with CaCl₂ and Ca(OH)₂, the supercooling degree of NFPCM decreased to 1.82 °C, which was 89% lower than that of the pure eutectic salt solution. Furthermore, the NFPCMs still showed excellent stability after 400 thermal cycles. The results show that the NFPCMs has high latent heat, higher thermal conductivity, low supercooling degree and excellent thermal stability, which makes it have practical application value and broad development prospects in the field of the cold chain.

随着冷链物流的迅猛发展，对低温产品（例如新鲜产品，化学用品和医疗疫苗）的冷藏运输设备的需求不断增长。对于某些运输温度较低的产品，仍需要开发温度范围为-10 C至-40°C的相变材料（PCM）。本文重点研究热力学性能优良，制备方法简单，成本低的低相转变温度纳米流体相变材料（NFPCM）。23 wt％氯化镁₂低共熔溶液用作NFPCM中的相变材料，其中多壁碳纳米管（MWCNT）和成核剂在降低过冷度方面起支持作用。那样的话，MWCNT的添加增加了热导率，并且增稠剂黄原胶（XG）可以防止相分离和附聚。具有1wt％的MWCNT的NFPCM具有-34.54℃的相变温度，146.9kJ kg ^-1的相变焓和0.5344W（m k）^-1的导热率。同样，在多壁碳纳米管与CaCl ₂和Ca（OH）₂的协同作用下，NFPCM的过冷度降至1.82°C，比纯共晶盐溶液低89％。此外，NFPCM在400个热循环后仍显示出出色的稳定性。结果表明，NFPCM具有较高的潜热，较高的导热系数，较低的过冷度和优异的热稳定性，使其在冷链领域具有实用的应用价值和广阔的发展前景。