室内颗粒运动和分布的模拟方法

本文论述了模拟室内颗粒运动和分布规律的不同方法,包括集总参数模型、区域模型以及基于计算流体力学的模型。结合一些相关的实例,文中分别阐述了这些方法的特点、适合的应用对象和使用策略等。     

新风预处理概念、系统与应用

美国《ASHRAE标准62－1999》要求增大空调系统的设计新风量,降低室内相对湿度以提高室内空气品质。这样,空调系统的冷、湿负荷将增大。据此,提出了新风预处理概念,它是在基本保持原有的传统空气处理系统不变的前提下,对新风进行合适的预处理,以消除增加的新风对空调对象的干预,从而经济有效地改善室内空气品质。最后,给出了几种新风预处理系统及应用。     

用于提高室内空气品质的新风预处理系统

随着对各种病态建筑综合症认识的逐步深入 ,国内的公众越来越注重室内空气品质( IAQ) ,迫切要求提高 IAQ.本文给出了几种新风预处理系统形式 ,可以经济有效的提高室内空气品质     

室内颗粒污染的源辨识与源解析

辨识室内颗粒物来源与分析室内颗粒物元素特征称为源辨识与源解析,是进行室内空气污染控制与净化的理论依据与前提条件。本文通过对室内空气品质（IAQ）模型进行理论分析,阐明了室内外污染源与室内颗粒物浓度之间的关系。指出室内颗粒污染物研究应根据污染源已知与未知两种情况进行讨论,并针对不同的情况分别采用源辨识与源解析技术。     

建筑热环境和室内空气质量综合模拟软件介绍

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。     

PROBE-PM: A new way to simulate particle transport in ventilation systems

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.     

How do breath and skin emissions impact indoor air chemistry?

People are an important source of pollution indoors, through activities such as cleaning, and also from “natural” emissions from breath and skin. This paper investigates natural emissions in high‐occupancy environments. Model simulations are performed for a school classroom during a typical summer in a polluted urban area. The results show that classroom occupants have a significant impact on indoor ozone, which increases from ~9 to ~20 ppb when the pupils leave for lunch and decreases to ~14 ppb when they return. The concentrations of 4‐OPA, formic acid, and acetic acid formed as oxidation products following skin emissions attained maximum concentrations of 0.8, 0.5, and 0.1 ppb, respectively, when pupils were present, increasing from near‐zero concentrations in their absence. For acetone, methanol, and ethanol from breath emissions, maximum concentrations were ~22.3, 6.6, and 21.5 ppb, respectively, compared to 7.4, 2.1, and 16.9 ppb in their absence. A rate of production analysis showed that occupancy reduced oxidant concentrations, while enhancing formation of nitrated organic compounds, owing to the chemistry that follows from increased aldehyde production. Occupancy also changes the peroxy radical composition, with those formed through isoprene oxidation becoming relatively more important, which also has consequences for subsequent oxidant concentrations.     

Stratum ventilation – A potential solution to elevated indoor temperatures

There is worldwide plea to reduce carbon dioxide emission. In response to such a call, several governments in East Asia recently have required to adopt higher room temperatures in summer. To promote such an idea, the public need to be convinced that such practice would not sacrifice indoor environmental quality, especially thermal comfort of the occupants. To implement such a measure, suitable ventilation system(s) to work under the unconventional conditions should be identified.     

民用建筑中央空调系统的污染对室内空气品质(IAQ)的影响和控制措施

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。     

室内化学污染物的评价新方法

论述了化学污染物是导致室内空气品质问题的主要原因,提出CO2和HCHO可以作为评价室内化学污染水平的代表,并建立了各自的对数评价指标的定义式,验证了对数评价指标与不满意率之间存在很好的线性相关关系,定义了反映室内化学污染水平的综合评价指数,给出了综合指数的计算方法,并按综合评价指数对室内污染水平进行了分类。     

Field measurements of indoor air pollutant concentrations on two new ships

Indoor air quality (IAQ) on ships is important for the passengers’ comfort and the crew’s work efficiency, despite ships not being as common as vehicles and airplanes. The builders and operators need to be aware of the importance and present status of IAQ, but sufficient data and information are not available. In this study, we measured the pollutant concentrations on two different kinds of newly launched ships: a passenger ship and a chemical cargo ship. Although higher than in the passenger ship, the concentrations of most volatile organic compounds (VOCs) and formaldehyde in the cargo ship were lower than the recommended standards and acceptable with a few exceptions. The high CO and CO₂ concentrations in the kitchen, engine room, and engine control room were generally attributed to combustion sources. Overall, the IAQ of the cargo ship was worse than that of the passenger ship, and the concentrations of some pollutants surpassed the international criteria. For the passenger ship, the variation of IAQ was also investigated after 17 months. The observed data showed some differences in concentration variation according to the types of pollutants. To improve IAQ on ships, more data need to be collected and minimum requirements suggested.     

Modeling particle fate in ventilation system—Part II: Case study

In this paper the particle filter group model, which was presented in the first part of this series of study, is employed to predict particle fate in a typical ventilation system. The model simultaneously takes into account the interactions between particle transport in ventilation ducts and rooms and particle spatial distribution. It has been proven that an entire ventilation system, including filters, ducts and rooms, can be regarded as a serial of filters in steady-state cases, hence the name “particle filter group model”. With this model, the particle concentration and quantity of deposited particles in each part of the ventilation system can be easily calculated.     

Effect of internal partitions on the performance of under floor air supply ventilation in a typical office environment

This paper presents a case to investigate the effect of partitions in an office on the performance of under floor air supply ventilation system via computational fluid dynamics. The assessment is in terms of thermal comfort and indoor air quality with the use of a validated computer model. The results indicate that the partitions may significantly affect airflow and performance of a under floor air supply ventilation system. In particular, the presence of a gap above the partition wall is able to improve air distribution owing to less air re-circulation in the upper zone. Its effect on thermal comfort and indoor air quality indicators are evaluated.     

Effect of door opening on the performance of displacement ventilation in a typical office building

The purpose of this paper is to investigate, using a validated computational fluid dynamics simulation, the effect of the position of doors on performance of the displacement ventilation system. The results are reported in terms of thermal comfort and indoor air quality. The study focuses on a typical Hong Kong office under local thermal and boundary conditions. It was found that the presence of large heat sources such as from a window can cause the lateral movement of airflow, disrupting the convection effect which the displacement ventilation system relies on. Doors can create this situation when they are opened by changing the thermal boundary conditions of indoor spaces. The designer should be made aware of this possibility and make appropriate design decisions to accommodate for this fact.     

Modeling particle fate in ventilation system—Part I: Model development

Aerosol particles are regarded as one of the most significant pollutants in the indoor environment. These particles can travel through ventilation systems, thus impacting indoor air pollution. Accurate modeling and prediction of aerosol particle transport in ventilation systems is therefore a key component of indoor particle pollution. Since recycled air takes particles into the ventilation system again, it can be challenging to calculate the particle concentration in each part of the system. This study theoretically and experimentally proves that the entire ventilation system, including filters, ventilation ducts and ventilation rooms, can be regarded as a serial of filters in steady-state cases. We call this the particle filter group model. Equations are presented to calculate the particle concentration in each component of normal kinds of mechanical ventilation systems. With this model, the particle concentration and deposited particle quantity in each part of the ventilation system can be easily calculated. This model may help to control indoor particle pollution and guide the cleaning of ventilation ducts and filters.     

Indoor air quality audit implementation in a hotel building in Portugal

Hotels are designed to provide high levels of comfort for guests; however, frequent complaints related to uncomfortable thermal environment and inadequate indoor air quality (IAQ) appear. On the other hand, there is little research concerning IAQ audits of hotels up to now.     

Simulation of VOC emissions from building materials by using the state-space method

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.     

独立新风系统(DOAS)研究(1):综述

介绍了独立新风系统的概念、背景、组成、特点和历史及其与建筑物的环境安全性、绿色建筑评估体系的关系。指出这种系统能明显提高室内空气品质、人体舒适感,减少空调系统一次投资和运行费用。