Study on ventilation standard based in ventilation efficiency

由于室内的通风效率并不总是均匀分布的，因此需要一个测量某一点或某局部通风效率的指标。局部通风效率通常用局部区域的平均浓度与房间排出空气的平均浓度之比来表示。从空气年龄理论可知，室内平均浓度与污染物的平均停留时间相对应。评估区域平均浓度意味着评估污染物在区域内的平均停留时间。它只能是整个房间的一部分，可以被认为是一个占领区。为此，本研究提出并分析了新的通风效率指标（VF、Tp和L-PFR）。引入访问频率（VF）和每次访问污染物在局部区域的平均停留时间（Tp）来分析污染物在局部区域的平均停留时间。More f VF的值受局部区域在房间中的位置，也就是局部区域在整个房间流场中的位置的强烈影响。Tp表示本域中流型的属性。由于VF和Tp指示了区域平均浓度的机理，因此它们与代表定义区域平均浓度的空气流量的局部吹扫流量（L-PFR）密切相关。VF、Tp和L-PFR的分析基于数值方法。为了验证数值模拟结果，进行了模型试验。模型由(x): (y): (z) = 1.5m: 0.7 m: 1组成。Om腔内设有一个0.02 m宽的进、出口槽。这个腔被分成三个更小的腔，由玻璃隔开。中心工作腔（宽度为0.3 m，对应于模型室）是进行测量的位置，另外两个腔（宽度为0.2 m）是再现工作腔中相同流型的位置（保护腔）。四个边界（天花板，地板，灯光和左墙）由水冷铝热交换器组成，以控制墙面温度。该模型实验积累了详细的流场数据。然后，结合实际办公空间和实验模型，进行了VF、Tp和L-PFR的数值模拟分析。少

Since ventilation efficiency in a room is not always uniformly distributed, an index for measuring ventilation efficiency at a concerned point or in a concerned local domain is required. Local ventilation efficiency is often represented by the rate of the averaged concentration of the local domain to that of exhausted air from the room. From the age theory of air, it is well-known that the averaged concentration in a room corresponds to the mean staying time of contaminant. Evaluating the domain averaged concentration means evaluating the average staying time of contaminant in the domain. It can be only one part of the whole room and can be considered as an occupied zone. Here, in this research, new index of ventilation efficiency (VF, Tp and L-PFR) are developed and analyzed. Visitation frequency (VF) and the average staying time of contaminant for one visitation in the local domain (Tp) are introduced to analyze the average staying time of contaminant in the local domain. The value o … More f VF is strongly affected by the position of the local domain in the room, in other words, the position of the local domain on the whole flow field of the room. Tp represents the property of the flow pattern in the local domain. Since VF and Tp indicate the mechanism of the domain averaged concentration, they are deeply related to local purging flow rate (L-PFR) which represents the air flow rate for defining the domain averaged concentration. Analysis of VF, Tp and L-PFR are based on the numerical method.In order to validate the results of numerical simulation, model experiment was carried out. A model was composed of (x) : (y) : (z) = 1.5m : O.7m : 1.Om cavity equipped with a O.02m width inlet and outlet slots. This cavity is divided into three smaller cavities, which is seperated by glass. The center working cavity (O.3m width, correspondance to model room), is the location where the measurements were performed, and the two other cavities (O.2m width) is the location where the same flow pattern as in the working cavity was reproduced (Guard cavity). Four boundaries (ceiling, floor, light and left walls) consists of water-cooling aluminium heat exchanger to control the wall surface temperature. Detailed data for flow fields are accumulated from this model experiment.Then, numerical simulations are carried out to analyze VF, Tp and L-PFR, concerning a actual office space and experimental model. Less