This study concerns an investigation into air movement and associated energy flows within the environment of a synthetic fibre producing factory. A multiplicity of airconditioning and ventilation systems were operated within the factory to provide a suitable atmosphere for the yarn, and also to allow some degree of comfort in hot production areas. Potential for improved operation of these systems was anticipated. Initial experiments showed certain anomalies and problems relating to air conditions and air movement; and an important facet of the production areas was identified as the regular partitioning created by the machine layout. A review of previous studies of building air flows indicated a lack of information relating to industrial and partitioned areas. Mathematical relationships for air flows were studied and the interactions of similar, closely spaced partitions were considered. A series of model scale tests using simple layouts supported a theory of interaction. The effect was substantial for wall type partitions and a considerable overestimation could result from the simple additive approach to determination of total resistance. At the factory a computer based monitoring scheme was designed and installed in order to establish environmental conditions and energy flows. The concept of "total thermal efficiency" was developed as a means of evaluating the performance of some of the air-conditioning systems. Considerable variations were evident between seasons and between systems; improvements being possible and recommended. Air flows were also investigated using Nitrous Oxide as a tracer gas. The effect of the internal partitioning combined with the high degree of ventilation and air-conditioning was to "compartmentalize" the spaces between the machines in the production areas, semi-isolating each from its neighbours. Thus, the results of the simplified model scale work could not be applied directly. However the isolation of the spaces offers potential for better systems operation by reducing air-conditioning requirements.

In December 2000, Program Budget Decision (PBD) 096 changed the way the Department of the Navy (DoN) budgets for Arabian Gulf operations. The cost of operations is now required to be submitted as part of the annual budget vice funded as contingency operations. In order to justify increased funding of incremental costs for operations in the Gulf, a method to justify such budget requests must be developed. This research developed a regression model targeted at the intermediate and depot level maintenance cost trends for Air Conditioning (A/C) systems based upon the assumption that the severe weather factors of the Gulf would impact the maintenance of A/C equipment. The model used ship age, deployed operational tempo (OPTEMPO), and temperature factors as explanatory variables in the model. The results of the regression analysis indicate the model does not provide evidence of increased maintenance costs of A/C systems for operations in the Gulf. Based on the inconsistencies in the maintenance data and the limitations of the explanatory variables, it is recommended that this approach be excluded from further research to justify increased budget requests for operations in the Gulf. / US Navy (USN) author

Thesis (M.S. in Management) Naval Postgraduate School, December 20012001. / "December 2001." Thesis Advisor(s): Mutty, John ; Liao, Shu S. Includes bibliographical references (p. 35-35).

No description available.

Introdução: Destaca-se a importância dos organismos do gênero Legionella como agentes causadores de doenças do aparelho respiratório como a legionelose ou doença do Legionário, e ainda de um controle na manutenção adequada de sistemas de ar condicionado, uma vez que estes foram identificados como ambientes favoráveis à proliferação desses microrganismos. Objetivo: Devido à importância de bactérias do gênero Legionella como agentes causadores de doenças, e um crescente número de casos de legionelose relacionados à permanência em ambientes fechados, este estudo teve como objetivo determinar a presença de Legionella em águas de bandejas de sistemas de ar condicionado. Métodos: Foram realizadas análises de amostras de água provenientes de bandejas de ar condicionado de dois hospitais, uma instituição de ensino superior e um centro comercial, totalizando 41 amostras. Volumes de 1L das amostras coletadas foram concentrados em membrana, seguida de tratamento ácido. Alíquotas das amostras tratadas e não tratadas com ácido, foram então inoculadas em meio Agar BCYE-, com e sem adição de antibióticos. As cepas isoladas foram submetidas a teste sorológico para identificação. Resultados: Das amostras analisadas, 4 (9,5%) apresentaram resultado positivo para Legionella sp.; uma no centro comercial e três em um dos hospitais estudados. Os isolados foram submetidos a teste sorológico, sendo um identificado como Legionella pneumophila sorogrupo 1 e três como seis prováveis espécies:L. longbeachae, L. bozemanni, L. dumoffi, L. gormanii, L. jordanis, L. micdadei, L. anisa . Conclusão: Os resultados deste estudo comprovam a presença de Legionella sp. nos sistemas de ar condicionado pesquisados, sendo observada maior freqüência dos isolados em amostras analisadas oriundas dos hospitais.Os resultados demonstraram a importância e a necessidade de planos de monitoramento em sistemas de 7 ar condicionado como medida preventiva à colonização por organismos patogênicos nesses sistemas e dessa forma proteger a saúde dos ocupantes e usuários de ambientes climatizados artificialmente. / Introduction: It highlights the importance of organisms genus Legionella as responsible for diseases of the respiratory system such as legionellosis or Legionnaires´disease, and a control on proper maintenance of air conditioning systems, as these were identified as favorable environment for the proliferation of these microorganisms. Objective: Due to the importance of Legionella as causative agents of disease and a growing number of cases of legionellosis related to stay indoors, this study aimed to determine the presence of Legionella in water samples from air-conditioning systems. Methods: We performed analysis of samples of water from trays of airconditioning systems in two hospitals, a university and a trade center, totalizing 41 samples. One liter volumes of water samples were concentrated on membrane, followed by acid treatment. Aliquots of the sample treated and not treated with acid, were inoculated on BCYE- agar medium, with and without added antibiotics. The strains were subjected to serological identification. Results: Out of the samples analyzed, 4 (9.5%) were positive for Legionella sp.; one in a trade center and three in one of the hospitals. Isolates were submitted to serological testing, one identified as Legionella pneumophila serogroup 1 and three as probable six species: L. longbeachae, L. bozemanni, L. dumoffi, L. gormanii, L. jordan, L. micdadei, L. anise. Conclusion: The results confirm the presence of Legionella sp. in air conditioning systems studied. It was observed a higher frequency in isolates from hospitals. The results demonstrated the importance and necessity of monitoring plans in air-conditioning systems as a preventive measure to colonization by pathogens in these systems and protect the health of occupants and users of these buildings.

Introdução: Destaca-se a importância dos organismos do gênero Legionella como agentes causadores de doenças do aparelho respiratório como a legionelose ou doença do Legionário, e ainda de um controle na manutenção adequada de sistemas de ar condicionado, uma vez que estes foram identificados como ambientes favoráveis à proliferação desses microrganismos. Objetivo: Devido à importância de bactérias do gênero Legionella como agentes causadores de doenças, e um crescente número de casos de legionelose relacionados à permanência em ambientes fechados, este estudo teve como objetivo determinar a presença de Legionella em águas de bandejas de sistemas de ar condicionado. Métodos: Foram realizadas análises de amostras de água provenientes de bandejas de ar condicionado de dois hospitais, uma instituição de ensino superior e um centro comercial, totalizando 41 amostras. Volumes de 1L das amostras coletadas foram concentrados em membrana, seguida de tratamento ácido. Alíquotas das amostras tratadas e não tratadas com ácido, foram então inoculadas em meio Agar BCYE-, com e sem adição de antibióticos. As cepas isoladas foram submetidas a teste sorológico para identificação. Resultados: Das amostras analisadas, 4 (9,5%) apresentaram resultado positivo para Legionella sp.; uma no centro comercial e três em um dos hospitais estudados. Os isolados foram submetidos a teste sorológico, sendo um identificado como Legionella pneumophila sorogrupo 1 e três como seis prováveis espécies:L. longbeachae, L. bozemanni, L. dumoffi, L. gormanii, L. jordanis, L. micdadei, L. anisa . Conclusão: Os resultados deste estudo comprovam a presença de Legionella sp. nos sistemas de ar condicionado pesquisados, sendo observada maior freqüência dos isolados em amostras analisadas oriundas dos hospitais.Os resultados demonstraram a importância e a necessidade de planos de monitoramento em sistemas de 7 ar condicionado como medida preventiva à colonização por organismos patogênicos nesses sistemas e dessa forma proteger a saúde dos ocupantes e usuários de ambientes climatizados artificialmente. / Introduction: It highlights the importance of organisms genus Legionella as responsible for diseases of the respiratory system such as legionellosis or Legionnaires´disease, and a control on proper maintenance of air conditioning systems, as these were identified as favorable environment for the proliferation of these microorganisms. Objective: Due to the importance of Legionella as causative agents of disease and a growing number of cases of legionellosis related to stay indoors, this study aimed to determine the presence of Legionella in water samples from air-conditioning systems. Methods: We performed analysis of samples of water from trays of airconditioning systems in two hospitals, a university and a trade center, totalizing 41 samples. One liter volumes of water samples were concentrated on membrane, followed by acid treatment. Aliquots of the sample treated and not treated with acid, were inoculated on BCYE- agar medium, with and without added antibiotics. The strains were subjected to serological identification. Results: Out of the samples analyzed, 4 (9.5%) were positive for Legionella sp.; one in a trade center and three in one of the hospitals. Isolates were submitted to serological testing, one identified as Legionella pneumophila serogroup 1 and three as probable six species: L. longbeachae, L. bozemanni, L. dumoffi, L. gormanii, L. jordan, L. micdadei, L. anise. Conclusion: The results confirm the presence of Legionella sp. in air conditioning systems studied. It was observed a higher frequency in isolates from hospitals. The results demonstrated the importance and necessity of monitoring plans in air-conditioning systems as a preventive measure to colonization by pathogens in these systems and protect the health of occupants and users of these buildings.

Simulation is one of the oldest and also among the most important tools available to engineers. In the building Heating, Ventilating and Air-Conditioning (HVAC) community the availability and/or functionality of simulation tools is limited and it is difficult to determine whether the simulation models accurately represent reality. The purpose of this study was to accurately verify one such a simulation model and then to extend the study to two unique applications. Comprehensive structural, comfort and energy audits were performed to construct a suitable simulation model with the aid of the control simulation package: QUICK Control. The model was then verified against measured building data to ensure an accurate representation of the actual dynamic building response. For the first application various control retrofits were evaluated and the highest potential for energy saving was found. Thereafter the model was implemented to investigate the change in indoor air conditions due to failure of HVAC equipment. Heating, ventilating and air-conditioning in buildings consume a significant portion of the available electrical energy in South Africa. Of this energy up to 30% can be saved by improving the HVAC systems currently installed in the buildings. This could result in savings of up to R400 million. For the building used in this study it was found that up to 66% of the HVAC system’s electrical energy consumption could be saved with a payback period of only 9 months. These savings could be achieved by implementing a setback control strategy with an improved time management procedure. Predicting the impact of failing equipment is a difficult task because of the integrated dynamic effect every HVAC component has on the next. With the aid of a comprehensive integrated simulation model the implications of failing can be determined and necessary assessments and precautions can be taken. The results of this study showed that the air-conditioning system under investigation was approximately 100% over designed. Failure of up to 50% was allowable in the cooling equipment before any noticeable impact could be observed in the indoor climate. With further failure the required comfort conditions could not be sustained. <p The substantial savings calculation and possibility of predicting climate deterioration would not have been possible without the aid of a comprehensive simulation package and model. This study clearly highlights the worth of integrated simulation. / Dissertation (MSc (Mechanical Engineering))--University of Pretoria, 2006. / Mechanical and Aeronautical Engineering / unrestricted

Heating, ventilation and air-conditioning (HVAC) systems are widely distributed over the world due to their capacity to adjust some local climate parameters, like temperature, relative humidity, cleanliness and distribution of the air until the desired levels verified in a hypothetical ideal climate. A review of buildings’ energy usage in developed countries shows that in the present this energy service is responsible for a portion of about 20% of the final energy usage on them, increasing up to 50% in hot-humid countries. In order to decrease this value, more and more different heat recovery systems have been developed and implemented over the last decades. Nowadays it is mandatory to install one of these units when the design conditions are above the limit values to avoid such components, what is possible to verify mostly in non-residential buildings. Each one of those units has its own performance and working characteristics that turns it more indicated to make part of a certain ventilation system in particular. Air-to-air energy recovery ventilation is based on the heat recovery transfer (latent and/or sensible) from the flow at high temperature to the flow at lower temperature, pre-warming the outdoor supply air (in the case of the winter). Therefore, it is important to understand in which concept those units have to be used and more important than that, how they work, helping to visualize their final effect on the HVAC system. The major aims of this study were to investigate the actual performance of the heat recovery units for LB20 and LB21 in building 99 at the University of Gävle and make some suggestions that could enhance their actual efficiency. Furthermore, the energy transfer rates associated to the heat recovery units were calculated in order to understand the impact of such components in the overall HVAC system as also the possible financial opportunity by making small improvements in the same units. To assess the system, values of temperature and flow (among others) were collected in the air stream and in the ethylene-glycol solution that works as heat transfer medium between air streams and is  enclosed in pipes that make part of the actual run-around heat recovery units. After some calculations, it was obtained that for the coldest day of measurements, the sensible effectiveness was 42% in LB20 and 47% in LB21, changing to 44% and 43% in the warmer day, respectively. The actual heat transfer representing the savings in the supply air stream is higher on the coldest day, with values of 46 kW in LB20 and 84 kW in LB21, justifying the existence of the heat recovery units even if those ones imply the use of hydraulic pumps to ensure the loop. The low values of efficiency have shown that both heat recovery units are working below the desired performance similarly to the pumps that make part of the same units.  This fact, together with the degradation of the units that is possible to observe in the local, indicates that a complete cleaning (followed by a change of the heat transfer medium) of the heat recovery units and a new adjustment of pumps and valves for the further changes, are necessary. By doing this, it is expected to see the year average sensible effectiveness increase to close to 45% in both units which will lead to a potential economic saving of around 41 000 SEK per year.

Dentre as tendências de uso racional de recursos, principalmente energia, e da necessidade de assegurar a produtividade e qualidade na execução de atividades produtivas, destaca-se o conceito de edifício inteligente. Este ambiente materializa o conceito de integração dos sistemas prediais potencializando a otimização dos recursos e a eficiência do trabalho humano. Neste contexto, abordagens conceituais baseadas em sistemas a eventos discretos e técnicas derivadas de rede de Petri têm sido introduzidas como uma alternativa eficaz de modelagem e análise das soluções de integração dos sistemas prediais. Um resultado expressivo destas iniciativas são os métodos propostos para a modelagem e análise de estratégias de gerenciamento de sistemas de ar condicionado, utilizando uma abordagem híbrida, onde são considerados os aspectos de sistemas a eventos discretos e as variáveis de dinâmica contínua. Contudo, as abordagens e métodos existentes são limitados a soluções específicas de implementação, como os sistemas de ar condicionado com volume de ar contínuo. Assim, o presente trabalho introduz uma extensão destas abordagens para modelar e analisar soluções de automação predial que incluem sistemas de ar condicionado com volume de ar variável. A eficiência deste método na concepção e validação destas soluções é ilustrada através de um estudo de caso. / Among the trends of rational use of resources, especially energy, and the need to ensure productivity and quality in the implementation of productive activities, there is the concept of intelligent building. This environment materializes the concept of integrating building systems, powering the optimization of resources and the efficiency of human labor. In this context, conceptual approaches that are based on systems of discreet events and techniques, which are derived from the Petri nets, have been introduced as an effective alternative to modeling and analysis of solutions of building systems integration. A significant result of these initiatives are the proposed methods for modeling and the analysis of strategies for air conditioning systems management using a hybrid approach where the aspects of systems of discreet events and the variables of continuing dynamic are considered. However, the existing methods and approaches are limited to their specific implementation solutions, such as air conditioning systems with continuous volume of air. Thus, this work introduces an extension of these approaches to model and analyze the building automation solutions that include air conditioning systems with variable volume of air. The efficiency of this method in the design and validation of these solutions is illustrated through a case study.

Dentre as tendências de uso racional de recursos, principalmente energia, e da necessidade de assegurar a produtividade e qualidade na execução de atividades produtivas, destaca-se o conceito de edifício inteligente. Este ambiente materializa o conceito de integração dos sistemas prediais potencializando a otimização dos recursos e a eficiência do trabalho humano. Neste contexto, abordagens conceituais baseadas em sistemas a eventos discretos e técnicas derivadas de rede de Petri têm sido introduzidas como uma alternativa eficaz de modelagem e análise das soluções de integração dos sistemas prediais. Um resultado expressivo destas iniciativas são os métodos propostos para a modelagem e análise de estratégias de gerenciamento de sistemas de ar condicionado, utilizando uma abordagem híbrida, onde são considerados os aspectos de sistemas a eventos discretos e as variáveis de dinâmica contínua. Contudo, as abordagens e métodos existentes são limitados a soluções específicas de implementação, como os sistemas de ar condicionado com volume de ar contínuo. Assim, o presente trabalho introduz uma extensão destas abordagens para modelar e analisar soluções de automação predial que incluem sistemas de ar condicionado com volume de ar variável. A eficiência deste método na concepção e validação destas soluções é ilustrada através de um estudo de caso. / Among the trends of rational use of resources, especially energy, and the need to ensure productivity and quality in the implementation of productive activities, there is the concept of intelligent building. This environment materializes the concept of integrating building systems, powering the optimization of resources and the efficiency of human labor. In this context, conceptual approaches that are based on systems of discreet events and techniques, which are derived from the Petri nets, have been introduced as an effective alternative to modeling and analysis of solutions of building systems integration. A significant result of these initiatives are the proposed methods for modeling and the analysis of strategies for air conditioning systems management using a hybrid approach where the aspects of systems of discreet events and the variables of continuing dynamic are considered. However, the existing methods and approaches are limited to their specific implementation solutions, such as air conditioning systems with continuous volume of air. Thus, this work introduces an extension of these approaches to model and analyze the building automation solutions that include air conditioning systems with variable volume of air. The efficiency of this method in the design and validation of these solutions is illustrated through a case study.