Coupling fast fluid dynamics and multizone airflow models in Modelica Buildings library to simulate the dynamics of HVAC systems
Coupling fast fluid dynamics and multizone airflow models in Modelica Buildings library to simulate the dynamics of HVAC systems
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DOI：
10.1016/j.buildenv.2017.06.013
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发表时间：
2017-09
影响因子：
7.4
通讯作者：
W. Tian;T. A. Sevilla;W. Zuo;M. Sohn
中科院分区：
文献类型：
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作者：
W. Tian;T. A. Sevilla;W. Zuo;M. Sohn
多区域模型因其计算速度快而广泛应用于建筑气流和能源性能模拟。然而，多区域模型假设房间内的空气混合良好，因此限制了它们的应用。在该假设不成立的特定房间中，使用计算流体动力学 (CFD) 模型可能是一种替代选择。先前的研究主要集中在耦合 CFD 模型和多区域模型来研究大空间中的气流。虽然这些分析很重要，但大多数分析并未考虑建筑物气流与建筑物供暖、通风和空调 (HVAC) 系统的耦合模拟。本文试图通过使用 Modelica 仿真平台将 HVAC 系统模型与耦合多区域和气流 CFD 仿真相集成来填补这一空白。为了提高计算效率，我们采用了名为快速流体动力学 (FFD) 的简化 CFD 模型。我们首先介绍Modelica中的数据同步策略和实现。然后，我们通过将模型模拟与实验数据进行比较，使用涉及等温流和非等温流的两个案例研究来验证实现。之后，我们研究了另外三个被认为更现实的案例。这是通过将可变风量 (VAV) 接线盒和 VAV 系统附加到先前的流来完成的，以评估模型在研究 HVAC 系统动态控制方面的能力。最后，我们讨论了使用模型进行耦合仿真的进一步研究需求。
Multizone models are widely used in building airflow and energy performance simulations due to their fast computing speed. However, multizone models assume that the air in a room is well mixed, consequently limiting their application. In specific rooms where this assumption fails, the use of computational fluid dynamics (CFD) models may be an alternative option. Previous research has mainly focused on coupling CFD models and multizone models to study airflow in large spaces. While significant, most of these analyses did not consider the coupled simulation of the building airflow with the building's Heating, Ventilation, and Air-Conditioning (HVAC) systems. This paper tries to fill the gap by integrating the models for HVAC systems with coupled multizone and CFD simulations for airflows, using the Modelica simulation platform. To improve the computational efficiency, we incorporated a simplified CFD model named fast fluid dynamics (FFD). We first introduce the data synchronization strategy and implementation in Modelica. Then, we verify the implementation using two case studies involving an isothermal and a non-isothermal flow by comparing model simulations to experiment data. Afterward, we study another three cases that are deemed more realistic. This is done by attaching a variable air volume (VAV) terminal box and a VAV system to previous flows to assess the capability of the models in studying the dynamic control of HVAC systems. Finally, we discuss further research needs on the coupled simulation using the models.