Due to the modernization and advancement in the society, the improvement of people’s living standard and the creation of comfortable and healthy indoor thermal environment has been a global concern for architects and building scientists. The ventilation system, which supplies air to meet the hygiene and thermal requirement of indoor occupants as well as to remove indoor pollutants, plays an important role in the control of indoor environment and energy saving of buildings. Traditionally, mixing ventilation (MV) is popular and widely used since it is easy to design and operate. The principle behind an MV system is to dilute the contaminated air by mixing it with the supplied fresh air. In MV, the whole space of a room is of concern, and the operation takes no consideration of the location of occupants and indoor sources. Consequently, researchers and building operators found that the effectiveness of MV is low, while energy consumption is high in many cases. To improve the efficiency of ventilation system, scientists emphasize the thermal satisfaction of the occupant in the local zone, i.e. the space around the occupant, rather than the entire room. Based on this idea, several advanced airflow technologies, e.g. personalized ventilation (PV), displacement ventilation, under floor air distribution and stratum ventilation, have been proposed. Different from MV, these advanced technologies focus on airflow patterns at a section of a room rather than the whole space. PV can even deliver the air directly to the breathing zone, and the supply air parameter of each inlet can be adjusted based on personalized requirements of the occupant. Generally, these advanced airflow patterns takes the occupied zone rather than the whole space into consideration; thus, the performance can be significantly improved. However, the occupancy is not uniformly distributed in an occupied zone, and positions of occupants are varied with time. In many cases, the zone really occupied by occupants is only a small part of the normal occupied zone. Although the advanced airflow patterns, which focus on the occupied zone, could improve the efficiency of the ventilation as compared with the traditional fully mixing ventilation, they are similar to MV in the occupied zone. When the number of occupants are much less than the design scenario for the purpose of the space, there is a great potential to improve the efficiency of the so-called advanced airflow pattern. Even for PV, the ventilation efficiency is not high when occupants are not close to the located air terminals. Can we realize the demand-oriented ventilation (DOV) for occupants wherever occupants are located? To achieve DOV, the ventilation system essentially should adapt and work efficiently to different scenarios with different occupant distributions. Therefore, the DOV system should be designed based on not only the design condition but also the partial load condition, especially those scenarios that frequently appear during operation. In the operation stage, the DOV system should have the ability to know the various positions of occupants and switch the ventilation mode into the most efficient one for the scenario. However, the traditional design and operation of ventilation system is based on the uniform indoor environment assumption. An integrated theory for non-uniform indoor thermal environments should be established, based on which the design method, theoretical model and control strategy of DOV can be developed; this is as shown in Figure 1. First, the principle of air distribution and the local cooling load of the non-uniform environment are the prerequisite of DOV. The computational fluid dynamics (CFD) has become a popular approach over past few decades, for the simulation of indoor parameters of

中文翻译：

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以需求为导向的通风离我们还有多远？

随着社会的现代化和进步，人们生活水平的提高，创造舒适健康的室内热环境，已成为全球建筑师和建筑科学家关注的问题。通风系统提供空气以满足室内居住者的卫生和热需求，并去除室内污染物，在控制室内环境和建筑节能方面发挥着重要作用。传统上，混合通风 (MV) 很受欢迎并被广泛使用，因为它易于设计和操作。MV 系统背后的原理是通过将受污染的空气与供应的新鲜空气混合来稀释污染空气。在MV中，关注的是房间的整个空间，操作时不考虑居住者的位置和室内源。最后，研究人员和建筑运营商发现，在许多情况下，MV 的效率很低，而能耗却很高。为了提高通风系统的效率，科学家们强调居住者在局部区域的热满意度，即居住者周围的空间，而不是整个房间。基于这个想法，已经提出了几种先进的气流技术，例如个性化通风（PV）、置换通风、地板下空气分配和地层通风。与 MV 不同的是，这些先进的技术专注于房间一部分而不是整个空间的气流模式。PV甚至可以直接将空气输送到呼吸区，每个进气口的送风参数可以根据乘员的个性化需求进行调整。一般来说，这些先进的气流模式考虑了占用区域而不是整个空间；因此，可以显着提高性能。然而，占用率在一个占用区域内并不是均匀分布的，并且占用者的位置随时间而变化。在很多情况下，居住者真正占用的区域只是正常占用区域的一小部分。尽管与传统的全混合通风相比，以占用区为重点的先进气流模式可以提高通风效率，但它们与占用区的MV相似。当居住人数远低于空间目的的设计场景时，所谓的先进气流模式的效率有很大的提高潜力。即使是光伏，当居住者离所设风口不近时，通风效率不高。无论居住者身处何地，我们都能实现以需求为导向的通风（DOV）吗？为了实现 DOV，通风系统本质上应该适应并有效地工作以适应具有不同居住者分布的不同场景。因此，DOV系统的设计不仅要根据设计工况，还要考虑部分负载工况，尤其是运行中经常出现的那些场景。在运行阶段，DOV系统应该能够知道乘员的各种位置，并根据场景将通风模式切换到最有效的模式。然而，传统的通风系统设计和运行是建立在室内环境均匀假设的基础上的。建立室内非均匀热环境综合理论，在此基础上发展DOV的设计方法、理论模型和控制策略；这如图1所示。首先，气流分布原理和非均匀环境的局部冷负荷是DOV的前提。在过去的几十年中，计算流体动力学 (CFD) 已成为一种流行的方法，用于模拟室内参数