Evaluation of comfort level in desks equipped with two personalized ventilation systems in slightly warm environments
Evaluation of comfort level in desks equipped with two personalized ventilation systems in slightly warm environments
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DOI：
10.1016/j.buildenv.2009.07.020
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发表时间：
2010-03
影响因子：
7.4
通讯作者：
E. Conceicao;M. J. Lúcio;S. P. Rosa;A. L. Custódio;R. L. Andrade;M. J. Meira
中科院分区：
文献类型：
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作者：
E. Conceicao;M. J. Lúcio;S. P. Rosa;A. L. Custódio;R. L. Andrade;M. J. Meira
在这项工作中，评估了教室的舒适度，即热舒适、局部热不适和空气质量水平，教室配备了两个个性化通风系统，在略微温暖的环境中。使用了一个假人，一个通风的教室桌子，两个室内气候分析仪，一个多节点人体热舒适性数值模型和一个计算流体动力学数值模型。课桌具有双功能，可供一名学生使用，位于右侧座位。每个个性化通风系统都配备了一个风道末端装置，一个位于写字台上方、后备区的前面，另一个位于写字台下方、腿部区域的前面。用多节点人体热舒适数值模型评价人体热舒适性，采用PMV值，用经验模型评价局部热不适程度，即风险性和风速波动当量频率，用计算流体动力学数值模型评价空气质量水平和人体周围的细部气流。在实验测试中，上风道末端装置的平均风速和湍流强度分别为3.5m/S和9.7%，而下风道末端装置的平均风速和湍流度分别为2.6m/S和15.2%。空气末端设备内的平均气温在28°C左右，而占用区域的平均辐射温度、远离占用区域的平均气温和内部平均空气相对湿度分别为28℃、28℃和50%。对乘员周围的15个人体部位的空气速度和温度进行了测量。实际的个性化通风系统，在呼吸区空气更新率最高的居住者周围促进上升的气流，根据目前的标准促进呼吸区可接受的热舒适条件和空气质量。在头部和左腿验证了通风风险，在左臂验证了不舒适的风速当量频率。左侧人体部分比右侧人体部分表现出更高的局部热不适程度，因为它们也受到左侧空气末端装置的影响。根据所获得的结果，课桌设计配备了两个个性化的通风系统，保证了可接受的热舒适条件，并促进了良好的空气质量条件，具有可接受的局部热不适条件和低能耗水平。
In this work the comfort level, namely the thermal comfort, local thermal discomfort and air quality levels, in a classroom with desks equipped with two personalized ventilation systems, in slightly warm environments, is evaluated. A manikin, a ventilated classroom desk, two indoor climate analyzers, a multi-nodal human thermal comfort numerical model and a computational fluid dynamic numerical model, are used. The classroom desk, with double occupation capacity, is used by a student, located in the right side seat. Each personalized ventilation system is equipped with one air terminal device located above the desk writing area, in front to the trunk area, and an other located below the desk writing area, in front to the legs area. The thermal comfort level is evaluated by the developed multi-nodal human thermal comfort numerical model, using a PMV value, the local thermal discomfort level, namely the draught risk and the air velocity fluctuation equivalent frequencies, is evaluated by empirical models, while the air quality level and the detailed airflow around the manikin are evaluated by the computational fluid dynamic numerical model. In the experimental tests the mean air velocity and the turbulence intensity in the upper air terminal device are 3.5m/s and 9.7%, while in the lower air terminal device are 2.6m/s and 15.2%. The mean air temperature in the air terminal devices is around 28°C, while the mean radiant temperature in the occupation area, the mean air temperature far from the occupation area and the internal mean air relative humidity were, respectively, 28°C, 28°C and 50%. The air velocity and temperature around the occupant are measured around 15 human body sections. The actual personalized ventilation system, which promotes an ascendant airflow around the occupant with highest air renovation rate in the respiration area, promotes acceptable thermal comfort conditions and air quality in the respiration area in accord to the present standards. The draught risk is verified in the head and left leg and the uncomfortable air velocity equivalent frequency is verified in the left arm. The left human body sections present higher local thermal discomfort levels than the right human body sections, because they are also influenced by the left air terminal device. In accord to the obtained results, the classroom desk design, equipped with two personalized ventilation systems, guarantees acceptable thermal comfort conditions and promotes good air quality conditions, with acceptable local thermal discomfort conditions and with low energy consumption level.