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1.
Conditions in which exhaled and dermally emitted bioeffluents could be sampled separately or together (whole‐body emission) were created. Five lightly dressed males exhaled the air through a mask to another, identical chamber or without a mask to the chamber in which they were sitting; the outdoor air supply rate was the same in both chambers. The carbon dioxide concentration in the chamber with exhaled air was 2000 ppm. Chamber temperatures were 23°C or 28°C, and ozone was present or absent in the supply airflow. When dermally emitted bioeffluents were present, the perceived air quality (PAQ) was less acceptable, and the odor intensity was higher than when only exhaled bioeffluents were present. The presence or absence of exhaled bioeffluents in the unoccupied chamber made no significant difference to sensory assessments. At 28°C and with ozone present, the odor intensity increased and the PAQ was less acceptable in the chambers with whole‐body bioeffluents. The concentrations of nonanal, decanal, geranylacetone, and 6‐MHO were higher when dermally emitted bioeffluents were present; they increased further when ozone was present. The concentration of squalene then decreased and increased again at 28°C. Dermally emitted bioeffluents seem to play a major role in the sensory nuisance experienced when occupied volumes are inadequately ventilated. 相似文献
2.
Particle deposition in a fully developed turbulent duct flow was studied. The random walk model of Lagrangian approach was used to predict the trajectories of 3000 particles with a density of 900 kg/m3. The effects of thermophoretic force and air humidity were also considered. The results were compared with the previous studies with a particle size range of 0.01–50 μm and air flow velocity of 5 m/s. The profile of dimensionless deposition velocity with relaxation time presents a V-shaped curve and the results are in good agreement with the previous studies.The effects of air temperature and humidity on particle deposition with a particle size of 1 μm were also investigated. The results show that thermophoretic force accelerates particle deposition onto the duct walls with increasing temperature difference between air flow and the duct wall surface. Meanwhile, it was found that particle deposition velocity increases with air humidity. 相似文献
3.
本文首先阐述了研究室内空气品质(IAQ)问题的重要性和必要性,介绍了目前已有的与室内空气品质相关的模拟软件。而后,基于"室内健康、环保和节能"的理念,提出了新的室内污染物浓度动态网络模拟分析与评估软件(DeST-IAQ)的理论框架,主要是将自然通风通路和机械通风网络集成,构成建筑通风和污染物传播的多区域网络模型,实现建筑通风和污染物浓度的联合动态预测,解决建筑通风模型、热模型和IAQ模型统一模拟的难题,满足建筑物能耗和室内空气品质预测的双重需求。该软件已在一些实际案例中得到了初步应用,其实用性具有较好的实验验证。 相似文献
4.
There are many mass-transfer models for predicting VOC emissions from building materials described in the literature. In these models, the volatile organic compound (VOC) emission rate and its concentration in a chamber or a room are usually obtained by analytical method or numerical method. Although these methods demonstrate some salient features, they also have some flaws, e.g., for analytical method the solutions of both room or chamber VOC concentration and building material VOC emission rate are constituted of the sum of an infinite series, in which additional computation for finding roots to a transcendental function is necessary, but sometimes quite complicated. Besides, when it is applied in complex cases such as multilayer emission with internal reaction, the solution is very difficult to get; for conventional numerical methods such as finite difference method, discrete treatment of both time and space may cause calculation errors. Considering that, the state-space method widely used in modern automation control field and the heat transfer field is applied to simulate VOC emissions from building materials. It assumes that a slab of building material is composed of a number of finite layers, in each of which the instantaneous VOC concentration is homogenous during the entire process of emission, while the time is kept continuous. Based on this assumption we can predict both the VOC emissions rate and the concentrations of VOCs in the air of a chamber or room. The method is generally applied to simulate VOC emissions from arbitrary layers of building materials, and the solution is explicit and simple. What's more, the method can be applied to the cases where a reaction producing/removing VOC in building materials exists. For some specific cases the method is validated using the experimental data and the analytical solutions in the literature. The method provides a simple but powerful tool for simulating VOC emissions from building materials, which is especially useful in developing indoor air quality (IAQ) simulation software. 相似文献
5.
A ventilation system usually runs on a certain schedule. The boundary conditions, such as the time-dependent outdoor particle
concentrations and indoor particle generating sources, vary dynamically. Ventilated rooms are connected to ventilation ducts
and filters, and indoor particle concentration and particle deposition on duct surfaces are interdependent. Thus it is important
to study particle transport in the entire ventilation system and take the dynamic characteristics into account to assess particle
pollution in the entire system more accurately. A generalized model is proposed in this study to estimate particle concentration
throughout an entire ventilation system as well as mass loading of particles on ventilation components. Model equations describe
particle movement in different ventilation components, including filters, ducts, and rooms. Penetration factors are adopted
for filters and ducts, and particle concentrations in rooms are calculated by a lumped parameter method. This generalized
model can be applied to any ventilation system, and a new software, PROBE-PM, was developed based on the presented model.
Four case studies are carried out using this new software to demonstrate the application of the model. 相似文献
6.
7.
文章分析了空调系统的污染对室内IAQ(Indoors Air Quality)的影响程度,指出随着其它污染源被控制,其影响将更加突出;分析了空调系统各部件污染的成因,以及这些污染对IAQ的影响。根据国内外相关文献,结合空调系统设计运行情况和工作实践,提出防止空调系统污染的措施。 相似文献
8.
9.
采用新风系统是改善室内空气品质最有效的方法。针对目前分体式空调器无法满足舒适性空调中洁净度要求等的情况,设计研制了一种带新风系统的分体壁挂式空调器。该系统尽管制造成本和安装难度有所增加,但对比测试表明,室内CO2浓度明显下降,没有带来新的噪声污染,室内人员普遍反映室内空气品质有极大改善。 相似文献
10.