Abstract

Ventilation is a way of improving the air quality of rooms by circulation. The position of the inlet and outlet greatly influences the thermal comfort. This attempt proposes to analyse the effect of the position of window openings for a room building with natural ventilation and the air flow and temperature distribution numerically using a commercial computational fluid dynamics (CFD) code. This proposed study consists of (i) approving the numerical model against experimental data gathered in an environment similar to the one used in simulations and (ii) applying the CFD model to explore the results of four varying configurations of ventilator on the natural ventilation system and thermal comfort. For the varying arrangements, the wind speed is 0.2 m⋅s⁻¹ perpendicular to the openings for a wind, (iii) evaluating the comfort level utilizing the Air Diffusion Performance Index (ADPI) on the basis of ASHRAE 55-210 criteria. The obtained results show that the positions of outlet and inlet openings highly affect the performance in the thermal comfort while they have a trivial effect on the occupied zone mean velocity. The computational results showed that the two cases (a) and (b) present results very close to each other with a slight difference at the center of the chamber. Most of the calculated values (effective draft temperature, EDT) are between (−1.7 and 1.1). Then ADPI is over 70% for case (a) and over 75% for case (b), so all points they are located in the comfort zone. The results affirmed also that configuration with inlet openings set at 1.022 m above ground and an outlet opening set at 0.52 m brings about the most applicable solution ventilation efficiency and give the best EDT that fulfills the criteria of ASHRAE 55-210 with an ADPI of ~90%.

中文翻译：

---

进出风口对自然通风建筑热工性能的影响

摘要

通风是一种通过循环改善房间空气质量的方法。进出口的位置对热舒适性影响很大。这项尝试建议使用商业计算流体动力学 (CFD) 代码以数值方式分析具有自然通风的房间建筑的窗户开口位置以及气流和温度分布的影响。这项拟议的研究包括（i）根据在与模拟中使用的环境相似的环境中收集的实验数据批准数值模型，以及（ii）应用 CFD 模型来探索自然通风系统上四种不同配置的通风机的结果，以及热舒适。对于不同的布置，风速为 0.2 m⋅s ^-1垂直于风口，(iii) 根据 ASHRAE 55-210 标准利用空气扩散性能指数 (ADPI) 评估舒适度。结果表明，出口和入口的位置对热舒适性的影响很大，而对占用区平均速度的影响很小。计算结果表明，（a）和（b）两种情况的结果非常接近，在腔室中心略有不同。大多数计算值（有效通风温度，EDT）在（-1.7 和 1.1）之间。那么情况 (a) 的 ADPI 超过 70%，情况 (b) 的 ADPI 超过 75%，因此所有点都位于舒适区。结果还证实了入口开口设置在地面以上 1.022 m 和出口开口设置为 0 的配置。