Virtual and physical experiments of encapsulated phase change material embedded in building envelopes
Virtual and physical experiments of encapsulated phase change material embedded in building envelopes
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DOI：
10.1016/j.ijheatmasstransfer.2021.121083
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发表时间：
2021-06
影响因子：
5.2
通讯作者：
Chunling Wu;Zhenhua Wei;H. Yin
中科院分区：
文献类型：
--
作者：
Chunling Wu;Zhenhua Wei;H. Yin
本文研究了用于节能建筑的相变材料复合材料的温度场和热流场。提出了一种新的数值方法，通过精确控制的实验室实验验证，更复杂的应用虚拟实验。考虑一个有限有界区域内含有一个夹杂，应用绿色函数技术，得到了夹杂区域和指定边界上的源引起的瞬态传热响应。基于Eshelby等效夹杂法（EIM），通过在相变颗粒上设置均匀分布的本征温度梯度场和虚拟热源，模拟了相变颗粒与基体相之间的热性能失配。将EIM与边界元法相结合，即iBEM，可以将温度场表示为边界上的温度和热流以及颗粒上分布的本征温度梯度和热源。利用等效热流条件和比热-温度关系，求解特征温度梯度和虚拟热源，计算有界区域的温度场。这种新的数值方法已被验证的有限元模拟和实验室测量的瞬态传热内含有PCM胶囊的积木。参数研究也进行了研究PCM的位置和体积分数的多颗粒复合材料的温度场的影响。通过虚拟实验验证了PCM-混凝土墙板的节能效果和相位延迟效果。该方法对建筑围护结构的设计和热工分析具有重要的参考价值。
This paper investigates the temperature and heat flux fields of composite materials containing phase change materials (PCM) for energy efficient buildings. A novel numerical method validated by accurately controlled laboratory experiments is presented for virtual experiments of more complex applications. Considering a finite bounded domain containing one inclusion, the Green’s function technique has been applied to obtain the transient heat transfer response caused by sources on inclusion domains and prescribed boundaries. Based on the Eshelby’s equivalent inclusion method (EIM), the thermal property mismatch between the PCM particle and matrix phases is simulated with a uniformly distributed eigen-temperature gradient field and a fictitious heat source on the particle. Through the combination of EIM and boundary element method, namely the iBEM, the temperature field can be written in terms of the temperature and heat flux on the boundary and the distributed eigen-temperature gradient and heat source on the particle. By using the equivalent heat flux conditions and the specific heat-temperature relationship, the eigen-temperature gradient and fictitious heat source can be solved and the temperature field of the bounded domain can be calculated. This new numerical method has been verified by the finite element simulation and validated with the laboratory measurements of the transient heat transfer within a building block containing a PCM capsule. Parametric studies have also been conducted to study the influences of the PCM location and volume fraction on the temperature field of composites with multiple particles. The virtual experiments demonstrate the energy saving and phase delay by using the PCM-concrete wall panel. This method will be very useful for the design and thermal analysis of building envelopes.