准备和性能研究n-Undecane相变冷藏材料的冷藏材料
Luchao Yan1, Yang Wang1, Shijian Lu1
1College of Material Science and Engineering, Nanjing Tech University, Nanjing 211816, China.
Materials (Basel, Switzerland)
|April 13, 2024
概括
使用n-undecane和PMMA的新型微囊提供了高效的冷藏解决方案. 优化的n-undecane/PMMA微囊为节能冷链物流提供了卓越的热性能.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 热力学是一种热力学.
背景情况:
- 冷链物流中的传统制冷方法是能源密集的.
- 开发新的储能材料对于节能和减少排放至关重要.
- 国家标准要求冷物流温度低于-18°C.
研究的目的:
- 开发和优化用于冷藏应用的微封装相变材料 (MEPCM).
- 调查乳化剂,核心比和乳化率对MEPCM性能的影响.
- 评估n-undecane/PMMA微囊的热性能和微表面形态.
主要方法:
- 悬浮聚合被用于制备n-undecane/PMMA微囊.
- 描述技术包括SEM,DSC,FTIR和激光粒子大小分析.
- 乳化剂的系统变化 (SMA,Tween-80,Tween-80/span-80),SMA剂量,核心比和乳化速度.
主要成果:
- SMA乳化剂产生了卓越的热性能和微表面形态,具有完整的核心外结构.
- 在最佳条件下 (7% SMA,2.5:1核心外比,2000rpm),相变的度最高 (120.3kJ/kg).
- MEPCM表现出良好的热稳定性和循环寿命,在200个循环后,度仅下降18.6kJ/kg.
结论:
- 优化的n-undecane/PMMA微囊是冷藏的有效相变材料.
- 这些微囊具有有利的微观结构,均的颗粒大小和高效的能量储存能力.
- 开发的MEPCM为制冷和冷行业提供了一个有前途的解决方案,与节能目标保持一致.
相关概念视频
01:19Phase Changes
4.3K
Phase transitions play an important theoretical and practical role in the study of heat flow. In melting or fusion, a solid turns into a liquid; the opposite process is freezing. In evaporation, a liquid turns into a gas; the opposite process is condensation.
A substance melts or freezes at a temperature called its melting point and boils or condenses at its boiling point. These temperatures depend on pressure. High pressure favors the denser form of the substance, so typically, high pressure...
A substance melts or freezes at a temperature called its melting point and boils or condenses at its boiling point. These temperatures depend on pressure. High pressure favors the denser form of the substance, so typically, high pressure...
4.3K
02:33Phase Transitions: Sublimation and Deposition
17.1K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
17.1K
01:03Sublimation
738
Sublimation is the direct transformation of a solid to a gaseous state. For instance, at standard pressure and room temperature, solid carbon dioxide sublimes to gaseous carbon dioxide. The phase diagram depicts the conditions required for sublimation. This process occurs at the solid-gas phase boundary and is not observed above the triple point of the substance. The reverse of sublimation is called deposition, where a gaseous substance condenses directly into a solid. Sublimation and...
738
02:44Heating and Cooling Curves
22.8K
When a substance—isolated from its environment—is subjected to heat changes, corresponding changes in temperature and phase of the substance is observed; this is graphically represented by heating and cooling curves.
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
22.8K
02:39Phase Transitions: Melting and Freezing
12.4K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.4K
00:59States of Matter and Phase Changes
947
The internal energy of a substance—the total kinetic energy of all its molecules and the potential energy of their associated forces—depends on the strength of the intermolecular forces in the condensed phases and the pressure exerted on the substance. The internal energy of a substance is the highest in the gaseous state, the lowest in the solid state, and intermediate in the liquid state. Phase transitions are caused by changes in physical conditions, such as temperature and...
947