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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An assessment of indoor air quality, lost work time, and perceived air quality in a Winnipeg school division

Swail, Heather 07 February 2014 (has links)
Indoor air quality measurements and staff absentee data were collected from elementary schools in a Winnipeg school division. Data was collected measuring carbon dioxide, carbon monoxide, temperature, relative humidity, particulate matter, and in some schools, radon. It was found that nearly all schools were experiencing some measure of IAQ problems. The most common issues measured were low levels of relative humidity and high concentrations of carbon dioxide. No significant relationships between staff absenteeism and IAQ parameters were identified in Pearson product-moment correlations and multiple regression analyses. Survey results found that 96% of respondents found IAQ problems in the workplace, and 79% of respondents show ‘sick building syndrome’-like symptoms. Recommendations have been provided to improve IAQ and establish an IAQ management program in order to improve the indoor environment in the school division.
2

An assessment of indoor air quality, lost work time, and perceived air quality in a Winnipeg school division

Swail, Heather 07 February 2014 (has links)
Indoor air quality measurements and staff absentee data were collected from elementary schools in a Winnipeg school division. Data was collected measuring carbon dioxide, carbon monoxide, temperature, relative humidity, particulate matter, and in some schools, radon. It was found that nearly all schools were experiencing some measure of IAQ problems. The most common issues measured were low levels of relative humidity and high concentrations of carbon dioxide. No significant relationships between staff absenteeism and IAQ parameters were identified in Pearson product-moment correlations and multiple regression analyses. Survey results found that 96% of respondents found IAQ problems in the workplace, and 79% of respondents show ‘sick building syndrome’-like symptoms. Recommendations have been provided to improve IAQ and establish an IAQ management program in order to improve the indoor environment in the school division.
3

Evaluation of Indoor Air Quality at Four Fitness Facilities

Newcomer, Derek A. 30 April 2004 (has links)
No description available.
4

An Overview of Indoor Air Quality

Yontz, Raymond Reese 10 May 2003 (has links)
This thesis is designed to introduce beginning and experienced heating, ventilation and air conditioning (HVAC) engineers to common indoor air quality (IAQ) problems and solutions. The bulk of the work is a literature review of common pollutants, pollutant sources, HVAC equipment and systems, and remediation techniques. Pollutants covered include fungi, bacteria, dust mites, viruses, biofilms, microbiological volatile organic compounds (MVOC?s), volatile organic compounds (VOC?s), carbon dioxide, ozone, and radon. The HVAC systems covered are ventilation, direct expansion (DX), desiccant dehumidification, and system filters. The remediation techniques discussed are proper hygiene and maintenance, increased ventilation, humidity control, and proper selection of building materials.
5

Air diffusion and solid contaminant behaviour in room ventilation v : a CFD based integrated approach

Einberg, Gery January 2005 (has links)
<p>One of the most fundamental human needs is fresh air. It has been estimated that people spend comparatively much time in indoor premises. That creates an elevated need for high-quality ventilation systems in buildings. The ventilation airflow rate is recognised as the main parameter for measuring the indoor air quality. It has been shown that the ventilation airflow rates have effects on respiratory diseases, on “sick building syndrome” symptoms, on productivity and perceived air quality. Ventilation is necessary to remove indoor-generated pollutants by diluting these to an acceptable level. The choice of ventilation airflow rate is often based on norms or standards in which the airflow rate is determined based on epidemiological research and field or laboratory measurements. However, the determination of ventilation flow rate is far more complex. Indoor air quality in the occupied zone can be dependent of many factors such as outdoor air quality, airflow rate, indoor generation of pollutants, moisture content, thermal environment and how the air is supplied into the human occupied zone. One needs to acknowledge the importance of air distribution which clearly affects the comfort of occupants. To design a ventilation system which considers all aspects of room ventilation can only be achieved by computer modelling. The objective of this thesis is to investigate air diffusion, indoor air quality and comfort issues by CFD (computational fluid dynamics) modelling. The crucial part of the CFD modelling is to adopt BCs (boundary conditions) for a successful and accurate modelling procedure. Assessing the CFD simulations by validated BCs enabled constructing the ventilation system virtually and various system layouts were tested to meet given design criteria. In parallel, full-scale measurements were conducted to validate the diffuser models and the implemented simplified particle-settling model. Both the simulations and the measurements reveal the full complexity of air diffusion coupled with solid contaminants. The air supply method is an important factor for distribution of heat, air velocity and solid contaminants. The influence of air supply diffuser location, contaminant source location and air supply method was tested both numerically and by measurements to investigate the influence of different parameters on the efficiency of room ventilation. As example of this, the well-known displacement ventilation is not fully able to evacuate large 10 μm airborne particles from a room. Ventilation should control the conditions in the human breathing zone and therefore the ventilation efficiency is an important parameter. A properly designed ventilation system could use less fresh air to maintain an acceptable level of contaminant concentration in the human breathing zone. That is why complete mixing of air is not recommended as the ventilation efficiency is low and the necessary airflow rate is relatively high compared to other ventilation strategies. Especially buoyancy-driven airflows from heat sources are an important part of ventilation and should not be hampered by supply airflow from the diffusers. All the results revealed that CFD presently is the only reliable method for optimising a ventilation system considering the air diffusion and contaminant level in all locations of any kind of room. The last part of the thesis addresses the possibility to integrate the CFD modelling into a building design process where architectural space geometry, thermal simulations and diffuser BCs could be embedded into a normal building design project.</p>
6

Development of Wireless Sensor Network System for Indoor Air Quality Monitoring

Borkar, Chirag 12 1900 (has links)
This thesis describes development of low cost indoor air quality (IAQ) monitoring system for research. It describes data collection of various parameters concentration present in indoor air and sends data back to host PC for further processing. Thesis gives detailed information about hardware and software implementation of IAQ monitoring system. Also discussed are building wireless ZigBee network, creating user friendly graphical user interface (GUI) and analysis of obtained results in comparison with professional benchmark system to check system reliability. Throughputs obtained are efficient enough to use system as a reliable IAQ monitor.
7

Air diffusion and solid contaminant behaviour in room ventilation : a CFD based integrated approach

Einberg, Gery January 2005 (has links)
One of the most fundamental human needs is fresh air. It has been estimated that people spend comparatively much time in indoor premises. That creates an elevated need for high-quality ventilation systems in buildings. The ventilation airflow rate is recognised as the main parameter for measuring the indoor air quality. It has been shown that the ventilation airflow rates have effects on respiratory diseases, on “sick building syndrome” symptoms, on productivity and perceived air quality. Ventilation is necessary to remove indoor-generated pollutants by diluting these to an acceptable level. The choice of ventilation airflow rate is often based on norms or standards in which the airflow rate is determined based on epidemiological research and field or laboratory measurements. However, the determination of ventilation flow rate is far more complex. Indoor air quality in the occupied zone can be dependent of many factors such as outdoor air quality, airflow rate, indoor generation of pollutants, moisture content, thermal environment and how the air is supplied into the human occupied zone. One needs to acknowledge the importance of air distribution which clearly affects the comfort of occupants. To design a ventilation system which considers all aspects of room ventilation can only be achieved by computer modelling. The objective of this thesis is to investigate air diffusion, indoor air quality and comfort issues by CFD (computational fluid dynamics) modelling. The crucial part of the CFD modelling is to adopt BCs (boundary conditions) for a successful and accurate modelling procedure. Assessing the CFD simulations by validated BCs enabled constructing the ventilation system virtually and various system layouts were tested to meet given design criteria. In parallel, full-scale measurements were conducted to validate the diffuser models and the implemented simplified particle-settling model. Both the simulations and the measurements reveal the full complexity of air diffusion coupled with solid contaminants. The air supply method is an important factor for distribution of heat, air velocity and solid contaminants. The influence of air supply diffuser location, contaminant source location and air supply method was tested both numerically and by measurements to investigate the influence of different parameters on the efficiency of room ventilation. As example of this, the well-known displacement ventilation is not fully able to evacuate large 10 μm airborne particles from a room. Ventilation should control the conditions in the human breathing zone and therefore the ventilation efficiency is an important parameter. A properly designed ventilation system could use less fresh air to maintain an acceptable level of contaminant concentration in the human breathing zone. That is why complete mixing of air is not recommended as the ventilation efficiency is low and the necessary airflow rate is relatively high compared to other ventilation strategies. Especially buoyancy-driven airflows from heat sources are an important part of ventilation and should not be hampered by supply airflow from the diffusers. All the results revealed that CFD presently is the only reliable method for optimising a ventilation system considering the air diffusion and contaminant level in all locations of any kind of room. The last part of the thesis addresses the possibility to integrate the CFD modelling into a building design process where architectural space geometry, thermal simulations and diffuser BCs could be embedded into a normal building design project. / QC 20101007
8

A Field Study of Airflow in a High-Rise Multi-Unit Residential Building

Ricketts, Lorne January 2014 (has links)
Airflow into, out of, and within buildings is fundamental to their design and operation as it can affect occupant health and comfort, building durability, and energy consumption. This thesis works to develop the understanding of airflow patterns and pressure regimes in high-rise multi-unit residential buildings which are both unique and complex due to the combination of their height, typical inclusion of operable windows, and compartmentalized layout. Specific attention is directed towards the performance of corridor pressurization based ventilation systems which are used pervasively within industry to ventilate and control contaminant transfer in these buildings. Airflow is caused by pressure differences which for buildings are created by the driving forces of wind, stack effect, and mechanical ventilation systems. These airflows are resisted by the air permeance (i.e. airtightness) of building elements including the exterior enclosure and interior compartmentalizing elements. Using an experimental program at a case study building, this thesis assesses the interaction of these driving forces of airflow with the physical building to create the airflow patterns for a typical high-rise multi-unit residential building. Perflourocarbon tracer (PFT) testing was performed to measure in-service airflows into and out of the suites. This testing found that the air change rates of upper suites are significantly higher than that of lower suites and that most suites receive small fractions of modern ventilation rates or are over ventilated. Airflow measurements of the supply of ventilation air to each corridor indicate that these low flow rates are in part due to leakage of air from the supply duct. The PFT testing also found that significant airflow occurred from the parking garage below the building into the occupied building spaces indicating significant potential for transfer of harmful air contaminants. The air permeance of the exterior enclosure and interior compartmentalizing elements were measured using neutralized fan pressurization and depressurization techniques and found to be within typical ranges. In particular this testing found that only 20% of the flow paths out of the corridor were to the adjacent suites through the suite entrance doors and that flows to the elevator shaft and stairwells could create a significant inefficiency in the ventilation system. A long-term monitoring program was implemented at the case study building primarily to monitor exterior environmental conditions including wind and exterior temperature and to correlate these with measured pressure differences. A strong correlation was found between building pressure and exterior temperature. Nearly 70% of the theoretical stack effect pressure was measured to act across the corridor to suite pressure boundary which creates a significant pressure differences to be overcome by the ventilation system, likely contributing to the uneven distribution of ventilation rates. Both wind and stack effect pressures were found to often be of similar or greater magnitude than mechanically induced pressure differences and thus can overwhelm the ventilation system. Overall, the corridor pressurization based ventilation system at the case study building does not effectively or efficiently ventilate the building and also does not provide sufficient control of air contaminants. As the case study building was found to be relatively representative of a typical multi-unit residential building, the findings from this building can be extended to many other buildings. Effective ventilation and airflow control in multi-unit residential buildings likely requires suite compartmentalization and direct supply of ventilation via ducted or in-suite systems.
9

SPATIOTEMPORAL MAPPING OF CARBON DIOXIDE CONCENTRATIONS AND FLUXES IN A MECHANICAL VENTILATION SYSTEM OF A LIVING LABORATORY OFFICE

Junkai Huang (15347227) 29 April 2023 (has links)
<p>Indoor air quality in office buildings can impact the health, well-being, and productivity of occupants. In most buildings, occupants exhaled breath is the primary source of carbon dioxide (CO<sub>2</sub>). Concentrations of indoor CO<sub>2</sub> are also strongly associated with the operational mode of the mechanical ventilation system. While CO2 is routinely monitored in indoor environments, there are few spatially-resolved real-time measurements of CO<sub>2</sub> throughout mechanical ventilation systems. Such measurements can provide insight into indoor- and outdoor-generated CO<sub>2</sub> dispersion throughout a building and between the building and the outdoor atmosphere. This thesis aims to investigate spatiotemporal variations in CO<sub>2</sub> concentrations and mass fluxes throughout a mechanical ventilation system of a living laboratory office in a LEED-certified building. The impact of human occupancy patterns and ventilation conditions of CO<sub>2</sub> concentrations and fluxes was evaluated. </p> <p>A four-month measurement campaign was conducted in one of the four living laboratory offices at the Ray W. Herrick Laboratories. The living laboratory offices feature precise control and monitoring of the mechanical ventilation system via an advanced building automation system. Various mechanical ventilation modes were implemented, such as variable outdoor air exchange rates (AERs) and recirculation ratios. A novel multi-location sampling manifold was used to measure CO<sub>2</sub> at eight locations throughout the ventilation system, such as across the outdoor, supply, and return air ducts. Office occupancy was measured via a chair-based temperature sensor array. Volumetric airflow rate data and CO<sub>2</sub> concentration data were used to estimate CO<sub>2</sub> mass fluxes through the ventilation system. The CO<sub>2</sub> mass flux for the outdoor and exhaust air was used to evaluate the net CO<sub>2</sub> transport from the office to the outdoor atmosphere. </p> <p>The measurements demonstrate that there exist significant spatiotemporal variations in CO<sub>2</sub> concentrations across the outdoor, supply, and return air ducts. CO<sub>2</sub> concentrations varied with human occupancy in the office and the outdoor AER of the mechanical ventilation system. Due to human-associated CO<sub>2</sub> emissions, the net CO<sub>2</sub> mass flux from the office to the outdoor environment was approximately 700 kg of CO<sub>2</sub> per year. Thus, occupied offices may represent an important, yet unrecognized, source of CO<sub>2</sub> to the urban atmosphere.</p>
10

Monitoramento e gest?o de vari?veis em ambiente fechado por meio de rede de sensores sem fio (RSSF) / Wireless sensor network (WSN) environmental variable monitoring and management

Paulino, Mateus Leandro 29 November 2017 (has links)
Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2018-03-06T17:33:50Z No. of bitstreams: 1 MATEUS LEANDRO PAULINO.pdf: 5831109 bytes, checksum: 844c1a030e8e0dad0c69291a01fd08fa (MD5) / Made available in DSpace on 2018-03-06T17:33:51Z (GMT). No. of bitstreams: 1 MATEUS LEANDRO PAULINO.pdf: 5831109 bytes, checksum: 844c1a030e8e0dad0c69291a01fd08fa (MD5) Previous issue date: 2017-11-29 / Pontif?cia Universidade Cat?lica de Campinas ? PUC Campinas / Searching for comfort and quality of life man has spent more than 90% of his time in artificial environments. Studies show that many serious diseases are occurring due to lack of a quality internal environment. In addition to the health consequences, a performance decrease in the accomplishment of daily tasks, such as intellectual, work and other activities is observed in the human being. The literature reports four factors that have the greatest effect on the quality of an environment: Thermal (temperature and humidity suited to its activities), Visual (correct intensity of luminosity), Acoustics (low repetitive noise level) and Air Quality (levels of gases and particulates in the air). Two of these invisible factors, the Thermal and the Air Quality, seriously stand out. In order to mitigate these effects, it is of the utmost importance to monitor and act on humidification, heating, air-conditioning, and automatic air exchange (ventilation) systems in order to guarantee comfort and tranquility for the occupants of a closed environment. The objective of this work is to propose a system to act on two of the above mentioned factors: Thermal Comfort (temperature and humidity) and Air Quality (CO2 gas concentration). In order to develop a technology that is both efficient and inexpensive, it is proposed that a Wireless Sensor Network (WSN) be used for communication between networked equipment, the choice of low cost boards and sensors, and the use of Infrared for sending commands to air conditioning and humidifier devices. As well as the development of a supervisory system to control actions and data collection. The tests were carried out in the computer laboratory of FEARP / USP (Faculdade de Economia, Administra??o e Contabilidade de Ribeir?o Preto). The graphs of the quantities collected were presented, table with activities of the day, performances and Alerts of the system. The system presented good operability and reliability in the treatment of environmental variables of the room. / Na busca pelo conforto e qualidade de vida o homem tem permanecido mais de 90% do seu tempo em ambientes artificiais e estudos comprovam que muitas doen?as graves est?o ocorrendo por falta de um ambiente interno de qualidade. Al?m das consequ?ncias ? sa?de, ? observada a queda de desempenho do ser humano na realiza??o das tarefas cotidianas tais como atividade intelectual, laboral e outras. A literatura relata quatro fatores que mais impactam a qualidade de um ambiente: o T?rmico (temperatura e umidade adequados a suas atividades), o Visual (intensidade correta de luminosidade), a Ac?stica (n?vel baixo de ru?dos repetitivos) e a Qualidade do ar (n?veis de gases e part?culas de polui??o adequadas no ar). Destaca-se com maior gravidade dois desses fatores que s?o invis?veis, o T?rmico e a Qualidade do ar. No sentido de mitigar estes efeitos, ? de suma import?ncia, monitorar e atuar sobre os sistemas umidifica??o, aquecimento, ar-condicionado, troca de ar (ventila??o) de forma automatizada, no sentido de garantir conforto e tranquilidade para os ocupantes de um ambiente fechado. O objetivo deste trabalho ? propor um sistema para atuar sobre dois dos fatores acima relatados: o Conforto T?rmico (temperatura e umidade) e Qualidade do Ar (concentra??o do g?s CO2). No sentido de desenvolver uma tecnologia ao mesmo tempo eficiente e de baixo custo ? proposto a utiliza??o de Rede de Sensores Sem Fio (RSSF) para comunica??o entre os equipamentos conectados em rede, a escolha de placas e sensores de baixo custo, uso de Infravermelho para envio de comandos aos dispositivos de ar-condicionado e umidificador, como tamb?m o desenvolvimento de um sistema supervis?rio para controle das a??es e coleta de dados. Os testes aconteceram no laborat?rio de inform?tica da FEARP/USP (Faculdade de Economia, Administra??o e Contabilidade de Ribeir?o Preto), foram apresentados os gr?ficos das grandezas coletadas, tabela com atividades do dia, Atua??es e Alertas do sistema. O sistema apresentou boa operacionalidade e confiabilidade no tratamento das vari?veis ambientais da sala.

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