Building calibration for IAQ management

Demand Control System (DCV) is designed to optimise the energy consumption with respect to the demand of outdoor air quantity based on the number of people indoors. However, if significant indoor pollutant sources exist, which is not a function of the number of people, the DCV may cause the indoor air quality to be unacceptable. This paper discusses a procedure of calibrating the building in respect of managing the indoor air quality. The objective is to set the minimum fresh air quantity which is a function of the indoor pollutant concentrations rather than metabolic carbon dioxide. Radon is used as an example because it is a common pollutant embedded in the building materials of high-rise buildings in Hong Kong. This paper also presents a year-round record of the indoor air quality in a typical high-rise building which is very useful for building indoor air quality (IAQ) design.     

Volatile organic compound emissions from latex paint--Part 2. Test house studies and indoor air quality (IAQ) modeling

Emission models developed using small chamber data were combined with an Indoor Air Quality (IAQ) model to analyze the impact of volatile organic compound (VOC) emissions from latex paint on indoor environments. Test house experiments were conducted to verify the IAQ model's predictions. The agreement between model predictions and experimental measurements met the American Society for Testing and Materials criteria for model verification in the room with the source and met most of the requirements in other rooms. The major cause of disagreement between the model predictions and the experimental data in the test house appears to be an inadequate sink model.     

基于室内空气品质的需求控制通风研究

本文研究的基于室内空气品质的需求控制通风，用CO2浓度作为室内人员相关污染物的控制指标，以TVOC作为室内建筑相关污染物的控制指标，从而容许在室内人员改变或建筑相关污染物浓度改变时调节入室新风量，实现了节能与提高室内空气品质的统一。文中对该方法理论和实验研究做了简要介绍。     

Multi-zone IAQ model

During the past decade, indoor air pollution emerged as an international health issue, and as a result a new field of simulation, indoor air quality analysis, is emerging. James Axley of the Indoor Air Quality and Ventilation Group at NIST, formerly National Bureau of Standards at Gaithersburg, has developed an integrated set of computer-aided tools and this paper reviews the present capabilities of the IAQ model, presents examples of its application and briefly outlines its theoretical base.     

Managing Exposure to Indoor Air Pollutants in Residential and Office Environments

Abstract Sources of indoor air pollutants in residential and office environments can be managed to reduce occupant exposures. Techniques for managing indoor air pollution sources include: source elimination, substitution, modification, pretreatment, and altering the amount, location, or time of use. Intelligent source management requires knowledge of the source's emission characteristics, including chemical composition, emission rates, and decay rates. In addition, knowledge of mechanical and natural outdoor air exchange rates, heating/air-conditioning duct flow rates, and local exhaust fan (e.g., kitchen, bathroom) flow rates is needed to determine pollutant concentrations. Finally, indoor air quality (IAQ) models use this information and occupant activity patterns to determine instantaneous and/or cumulative individual exposure. This paper describes a number of residential and office scenarios for various indoor air pollution sources, several ventilation conditions, and typical occupant activity patterns. IAQ model predictions of occupant exposures for these scenarios are given for selected source management options. A one-month period was used to compare exposures; thus, long-term exposure information is not presented in this paper.     

Multi‐zone IAQ model

During the past decade, indoor air pollution emerged as an international health issue, and as a result a new field of simulation, indoor air quality analysis, is emerging. James Axley of the Indoor Air Quality and Ventilation Group at NIST, formerly National Bureau of Standards at Gaithersburg, has developed an integrated set of computer‐aided tools and this paper reviews the present capabilities of the IAQ model, presents examples of its application and briefly outlines its theoretical base.     

Evaluation of distributed environmental control systems for improving IAQ and reducing energy consumption in office buildings

Conventional heating, ventilation, and air conditioning (HVAC) systems are incapable of providing control over individual environments or adjusting fresh air supply based on the dynamic occupancy of individual rooms in an office building. This paper introduces the concept of distributed environmental control systems (DECS) and shows that improvement in indoor air quality (IAQ) and energy efficiency can be achieved by providing required amounts of fresh air directly to the individual office spaces through distributed demand controlled ventilation (DDCV). In DDCV, fresh air is provided to each micro-environment (room or cubicle) based on input from distributed sensors (CO₂, VOC, occupancy, etc.) or intelligent scheduling techniques to provide acceptable IAQ for each occupant, rather than for groups or populations of occupants. In order to study DECS, a numerical model was developed that incorporates some of the best available models for studying building energy consumption, indoor air flow, contaminant transport and HVAC system performance. The developed model was applied to a DECS in a model office building equipped with a DDCV system. By implementing DECS/DDCV and intelligent scheduling techniques it is possible to achieve an improvement in IAQ along with a reduction in annual energy consumption compared to conventional ventilation systems.     

Experimental validation of a computational fluid dynamics model for IAQ applications in ice rink arenas

Many ice rink arenas have ice resurfacing equipment that uses fossil fuel as power. The combustion byproducts are a major source of contamination. Ventilation along with other pollution source control measures is the most widely applied strategy to lower the contaminant level below the threshold limit and maintain acceptable indoor air quality (IAQ). A computational fluid dynamics (CFD) model has been developed and used to predict the contaminant concentrations, air velocity, and air temperature distributions in ice rinks. The numerical results agree reasonably with the corresponding experimental data for both steady-state and transient conditions. The CFD model is a useful and inexpensive tool to investigate ventilation parameters, such as air distribution methods, ventilation effectiveness, air exchange rates, and various ventilation control strategies.     

确定建筑材料有害物散发量的三种传质模型

室内空气污染源散发量的确定是建立室内空气质量(IAQ)模型的重要步骤之一。目前研究建筑装饰材料和建筑涂料散发污染物的模型主要有经验模型和理论模型两类。经验模型简洁，但应用受到测试条件的限制，不具有普适性。基于传质理论而提出的理论模型目前研究较多，本文对研究建筑材料散发有害物的三个传质模型进行了评述。VB模型是一个简单的溶剂基室内涂料散发的总挥发性有机物(TVOC)的传质模型，低估了污染物的长期散发量。对流传质模型是基于界面平衡所导出的稳态模型，适用于固体和液体等材料的散发过程。Yang等提出的四层传质模型通常需与数值求解结合，计算较麻烦，但能较好地确定建筑材料散发挥发性有机物的散发量。     

溶液除湿方式对室内空气品质影响的初步研究

在溶液除湿空调空气处理过程中，因溶液与空气直接接触，可能对室内空气品质产生负面影响，但同时也可以去除空气中的有害物质。以溴化锂溶液为例，进行了室内空气溴、锂离子的测定，溴化锂溶液对甲醛的吸收实验，除湿溶液对细菌和病毒生长的影响实验，并初步探讨了气液交换模块的除尘作用。     

住宅室内空气品质及其改善途径

介绍了住宅室内空气的污染现状,指出住宅装饰装修、家具、人的日常活动等是造成住宅IAQ下降的主要原因;从环境及预防医学的角度阐述了室内空气污染对人体健康的危害;并从建筑技术、国家政策等方面提出了改善IAQ的途径。     

Model validation study of carbon monoxide transport due to portable electric generator operation in an attached garage

A series of tests was conducted to characterize the indoor carbon monoxide (CO) concentrations resulting from portable electric generators operating in the attached garage of a test house under various use and environmental conditions. An extensive model validation effort using the multizone airflow and indoor air quality (IAQ) model CONTAM was carried out using the data from seven tests with a generator operating in the attached garage to compare predicted CO concentrations with measured values. The agreement between the measurements and predictions of the O₂ concentrations in the garage and the average CO concentration for the house zones was excellent for the data set as a whole. The agreement was somewhat worse for the garage CO concentrations. Overall, the house zone average and garage CO concentration predictions and measurements were within about 20% and 30%, respectively, when averaged over all cases.     

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。     

空调系统设计和维护中影响IAQ的因素及其防治措施

本文总结了现行空调设计及其维护中存在的一些影响室内空气品质的因素，从空调系统成为污染源的原因及防治措施、新风的处理、新风量及室内设计参数、通风方式、局部污染较重的房间的处理、降低空调能耗及新风量控制等几个方面阐述了在考虑空气品质问题后，空调设计及系统维护应注意的问题。     

通风空调对室内空气品质的影响

加强通风空调系统对室内空气品质的正面作用,除了加大通风量外,近年来提高送风量的品质措施越来越多,本文强调的要深层次认识通风空调自身污染对室内空气品质的负面影响。针对目前空调系统的设计,提出了消除通风空调系统对室内空气品质负面影响、有效发挥其正面作用的一些措施。     

室内空气品质的新定义与新风直接入室方法的实验测试

不能把室内空气品质仅仅认同于一系列污染控制指标，应以人们对空气品质的满意程度来徇空气品质的高低。因此主观评价是判定室内空气品质的主要依据。新风对改善室内空气品质起着比其他因素更为重要的作用。本文着重研究将新风直接送入空调室，并采用独特的方法减少新风对室内温度场的速度场的干扰，室内人员普遍反映室内空气品质极大改善，而未感受到新风的干扰。     

马鞍山市大型商场室内空气质量研究

测试了马鞍山市某商场的甲醛浓度、二氧化碳浓度、微生物菌落数和温度、相对湿度、风速等环境参数,通过问卷调查了营业员和顾客对室内空气质量的评价,客观评价与主观评价的结果表明,商场内空气中主要污染物的浓度符合国家标准,但仍然存在空气质量方面的问题。     

Modeling the reversible,diffusive sink effect in response to transient contaminant sources

A physically based diffusion model is used to evaluate the sink effect of diffusion-controlled indoor materials and to predict the transient contaminant concentration in indoor air in response to several time-varying contaminant sources. For simplicity, it is assumed the predominant indoor material is a homogeneous slab, initially free of contaminant, and the air within the room is well mixed. The model enables transient volatile organic compound (VOC) concentrations to be predicted based on the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) of the sink. Model predictions are made for three scenarios, each mimicking a realistic situation in a building. Styrene, phenol, and naphthalene are used as representative VOCs. A styrene butadiene rubber (SBR) backed carpet, vinyl flooring (VF), and a polyurethane foam (PUF) carpet cushion are considered as typical indoor sinks. In scenarios involving a sinusoidal VOC input and a double exponential decaying input, the model predicts the sink has a modest impact for SBR/styrene, but the effect increases for VF/phenol and PUF/naphthalene. In contrast, for an episodic chemical spill, SBR is predicted to reduce the peak styrene concentration considerably. A parametric study reveals for systems involving a large equilibrium constant (K), the kinetic constant (D) will govern the shape of the resulting gasphase concentration profile. On the other hand, for systems with a relaxed mass transfer resistance, K will dominate the profile.     

Cooking generated particles’ impact on indoor air quality of university cafeteria

University cafeteria is a kind of building with unique characteristics: there are lots of people dining besides the large cooking area. It is of great importance to study the impact of the cooking generated contaminants on the indoor air quality in the cafeteria since cooking is regarded as the main source of indoor contaminants. This study presents the particulate matter (PM) concentrations measured in three different university cafeterias followed by a series of cases studied with CFD and multizone model simulation. Based on the results, the possible strategies to tackle the indoor air quality (IAQ) problem due to cooking are discussed. It is concluded that using up exhaust, setting up partition between cooking area with other zones and adding scuttles are helpful to reduce the cooking generated particle pollution in the cafeterias.     

Thermal comfort and IAQ characteristics of naturally/mechanically ventilated and air-conditioned bedrooms in a hot and humid climate

The characteristics of thermal comfort and indoor air quality (IAQ) in bedrooms, occupants’ perceptions and their impact on sleep quality are not often studied. It becomes even more interesting if climatic conditions allow Naturally/Mechanically Ventilated (NMV) concepts as opposed to Air-conditioning (AC) and this becomes very significant from an energy perspective. This paper reports our findings from such a study conducted in a hot and humid climate. Objective measurements of thermal comfort and IAQ were carried out during sleeping period in 12 NMV and 12 AC bedrooms over a period of 2 months. Questionnaire responses were sought from each subject at the end of the objective measurements to assess their perceptions on thermal comfort and indoor air quality of the bedrooms during sleep and their sleeping conditions. Although the “Historical” and “Immediate” responses for the NMV and AC bedrooms indicate that there was a good level of acceptability for both Thermal Comfort and Perceived Air Quality (PAQ), it was found that NMV bedroom was a better sleeping environment. The subjects’ immediate perception of PAQ and thermal comfort were reasonably correlated with their historical perceptions. The subjects’ perception of PAQ was fairly closely correlated to their perception of Thermal Comfort. There was a considerable increase in the carbon dioxide level in an AC bedroom relative to a NMV bedroom. However, there was no clear evidence to substantiate that sleeping duration decreased with increasing level of carbon dioxide, but the findings do suggest that high level of carbon dioxide may hinder the duration of sleep.