Master of Science / Department of Mechanical and Nuclear Engineering / Mohammad H. Hosni / Byron W. Jones / The 2015 Airline Traffic Data released by the Bureau of Transportation Statistics (BTS 2016), shows that the commercial flights serving the United States carried an all-time high of 895.5 million passengers in 2015, which represents an approximate 5 % increase in number of passengers from 2014. There is a potential for disease and/or contaminants spreading throughout the airliner cabin raising health risks for passengers and crewmembers onboard flight. In order to limit health risks caused by spread of disease and/or contaminants, it is necessary to understand the various factors affecting the airliner cabin environment. Ventilation effectiveness is one such factor investigated in this study. In addition, experiments were conducted using tracer gas to study the dispersion of tracer gas inside an airliner cabin. Experimental investigations were carried out inside a wide body, eleven-row Boeing 767 mockup cabin and a narrow body, five-row Boeing 737 mockup cabin. The Boeing 767 mockup cabin was constructed with actual aircraft components for air distribution to represent a real aircraft cabin, while the Boeing 737 mockup cabin is a fuselage section from an actual Boeing 737 aircraft. Thermal manikins occupied each seat of both the cabins to simulate thermal load from an average seated person. Four sets of experiments were conducted to evaluate the ventilation effectiveness and dispersion of tracer gas inside the aircraft cabin mockups. The first set of experiments investigated the ventilation effectiveness in a Boeing 767 mockup cabin. The second set of experiments determined the ventilation effectiveness at various heights and locations in a Boeing 737 mockup cabin. The third set of experiments focused on the study of dispersion of tracer gas inside a Boeing 737 mockup cabin with ventilation air. The last set of experiments aimed to study the dispersion of tracer gas inside a Boeing 737 mockup cabin with no ventilation air. The ventilation effectiveness studies were performed by using Carbon Dioxide (CO₂) as a tracer gas and applying the tracer gas decay method. The conclusion for the first set of experiments was that air is efficiently and uniformly supplied to all seat locations inside the Boeing 767 mockup cabin with no clear patterns with respect to seat locations, i.e. window versus center versus aisle observed. From the second set of experiments, it was concluded that the ventilation effectiveness is uniform throughout the Boeing 737 mockup cabin irrespective of seat locations and elevations from cabin floor. In order to determine the spread of disease and/or contaminants, a mixture of CO₂ and Helium (He) was used as a tracer gas. Tracer gas was released from particular locations inside the cabin to simulate gaseous contaminants released by a passenger and sampled at various locations throughout the cabin. The third set of experiments revealed that transport of tracer gas inside an aircraft cabin depends on the source location as well as on the relative distance of the sampling point from the source. Dispersion of tracer gas in the longitudinal direction was also observed inside the cabin. From the fourth set of experiments, it was concluded that even in the absence of ventilation air, considerable dispersion of tracer gas occurred in both the longitudinal and lateral directions.

A aplicação de sistemas de climatização com distribuição de ar pelo piso tem aumentado em países desenvolvidos, o que também tem ocorrido no Brasil. Em paralelo, tem crescido o interesse pela qualidade do ar interior e os seus efeitos no bem estar, saúde e produtividade dos ocupantes de uma edificação. Diversos estudos têm apontado para as vantagens deste sistema em relação à remoção de contaminantes do ambiente interior. Este sistema tem figurado nos programas de certificação ambiental de edificações como uma alternativa vantajosa para a melhoria da qualidade do ar interior e o conforto térmico com preservação da eficiência energética, recebendo pontuação adicional. Com o crescente interesse por este tipo de sistema, estudos que aprimorem o seu projeto visando à melhor eficiência global mostram-se essenciais. Este estudo tem como principal objetivo verificar experimentalmente a contribuição de um sistema de climatização com distribuição de ar pelo piso para a qualidade do ar interior de um ambiente, sendo este uma sala de aula para 48 alunos situada no Departamento de Engenharia de Construção Civil da Escola Politécnica da Universidade de São Paulo, em condições reais de uso. Para isso, foram medidas as concentrações de partículas em suspensão na zona de respiração para pessoas sentadas (a 1,10 m do piso), e no retorno do ar (a 2,60 m do piso) simultaneamente, sob seis diferentes valores de temperatura do ar na zona ocupada (a 0,60 m do piso), previamente escolhidos. Estas concentrações permitiram o cálculo e a análise do índice de efetividade na remoção de contaminantes IERC no ambiente, para partículas e CO2 (segunda etapa das medições). Simultaneamente, foram realizadas medições de variáveis de conforto térmico no ambiente, temperatura do ar e velocidade do ar, em seis diferentes alturas e quatorze pontos do ambiente. As baixas concentrações de partículas em suspensão (inferiores a 0,035 mg/m³) mostraram que este sistema não dispersa contaminantes no ar interior. Os IERC próximos ou superiores à unidade em todas as condições de operação do sistema, tanto para partículas em suspensão como para CO2, comprovaram a sua eficiência na remoção de contaminantes do ambiente interior. / The use of underfloor air distribution (UFAD) systems is growing in developed countries, and this is also observed in Brazil. Besides, the interest in indoor air quality and its effects on the well being, health and productivity of the occupants in a building is an important issue nowadays. Many studies have related the advantages of UFAD systems in removing indoor air contaminants from the ambient as compared to overhead systems. In the building certification systems, they figure as good alternatives to promote better indoor air quality and thermal comfort, preserving energy efficiency, which corresponds to additional points. With the expanding interest in this technology, studies that enhance its project, keeping as a goal its global efficiency, are very welcome. The aim is to experimentally verify the contribution of an UFAD system to the indoor air quality of a classroom used by 48 students at the Civil Construction Department of the Engineering School of the University of São Paulo Brazil. The study has been conducted in a non-steady state condition. In order to perform this evaluation, the levels of indoor air-borne particles were measured at the breathing zone for seated people (1.10m from the ground), and at the exhaust (2.60m from the ground) simultaneously, under six different pre-defined values of air temperature at the occupied zone (0.60m from the ground). These concentration levels have allowed calculating the contaminant removal effectiveness index, CRE, in many points of the ambient. A similar analysis was developed for the concentrations of CO2 in the second part of the experiment. At the same time, the air temperature and air velocity were measured in six different levels and at fourteen points of the ambient. The low concentration levels of total suspension particle (under 0.035 mg/m³) have shown that this system doesn\'t disperse air contaminants indoors. The CRE indexes near or above 1.0, for both total suspension particle and CO2, have confirmed the ventilation effectiveness of this underfloor air distribution system under all the operational conditions.

Energy use in buildings account for about one third of the total global energy supply and contributes as much as 30% of the anthropogenic greenhouse gas emissions. It is estimated that energy use in buildings will increase to 67% by 2030. The need for better thermal comfort and air quality in indoor environments is the leading cause for high energy use in buildings.  Heating, ventilation and air conditioning systems take up about 50% of the total energy use in buildings which is about 10-20% of the national energy use in most developed countries. The development and adoption of sustainable ventilation systems is a viable solution to mitigate climate change and curtail carbon emissions. The experimental study was conducted in a room resembling a modern office in a laboratory environment. The study involved investigating the ability of the system to provide cooling and heating. Concentration decay tracer gas technique using Sulphur hexafluoride (SF6) gas was used to determine the local air change index and air change efficiency in the room. Low-velocity omni-directional thermistor anemometer type CTA88 were used to measure the air velocity and temperature in the room. Smoke was used to visualise the flow patterns created in the room.  The climate chamber was used to mimic climatic conditions in winter. Fifteen cases were investigated with five air flow rates set points (30, 40, 50, 60 and 70 l/s) at three supply air temperatures, i.e., 17.6 °C, 21.0 °C and 25.3 °C. The results of the local air change index and air change efficiency for the nominal supply temperature of 17.6 °C showed that the system had strong characteristics of a mixing ventilation system. At the supply air temperature of 21.0 °C, the performance of the system deteriorated slightly to below that of a mixing ventilation system and could not satisfactorily provide heating at supply temperature of 25.3 °C. Better performance of the system at all supply air temperature setpoints was observed at lower airflow rates. At all supply air temperature setpoints, relatively higher degree of temperature stratification was observed at lower supply. The draught rate levels decreased with increase in supply air temperature and height. The location of the air inlet terminals in relation to the workstations had significant effect on the performance of the system. The stratum ventilation system did not work efficiently because the air streams were heavily mixed before reaching the occupants.

A aplicação de sistemas de climatização com distribuição de ar pelo piso tem aumentado em países desenvolvidos, o que também tem ocorrido no Brasil. Em paralelo, tem crescido o interesse pela qualidade do ar interior e os seus efeitos no bem estar, saúde e produtividade dos ocupantes de uma edificação. Diversos estudos têm apontado para as vantagens deste sistema em relação à remoção de contaminantes do ambiente interior. Este sistema tem figurado nos programas de certificação ambiental de edificações como uma alternativa vantajosa para a melhoria da qualidade do ar interior e o conforto térmico com preservação da eficiência energética, recebendo pontuação adicional. Com o crescente interesse por este tipo de sistema, estudos que aprimorem o seu projeto visando à melhor eficiência global mostram-se essenciais. Este estudo tem como principal objetivo verificar experimentalmente a contribuição de um sistema de climatização com distribuição de ar pelo piso para a qualidade do ar interior de um ambiente, sendo este uma sala de aula para 48 alunos situada no Departamento de Engenharia de Construção Civil da Escola Politécnica da Universidade de São Paulo, em condições reais de uso. Para isso, foram medidas as concentrações de partículas em suspensão na zona de respiração para pessoas sentadas (a 1,10 m do piso), e no retorno do ar (a 2,60 m do piso) simultaneamente, sob seis diferentes valores de temperatura do ar na zona ocupada (a 0,60 m do piso), previamente escolhidos. Estas concentrações permitiram o cálculo e a análise do índice de efetividade na remoção de contaminantes IERC no ambiente, para partículas e CO2 (segunda etapa das medições). Simultaneamente, foram realizadas medições de variáveis de conforto térmico no ambiente, temperatura do ar e velocidade do ar, em seis diferentes alturas e quatorze pontos do ambiente. As baixas concentrações de partículas em suspensão (inferiores a 0,035 mg/m³) mostraram que este sistema não dispersa contaminantes no ar interior. Os IERC próximos ou superiores à unidade em todas as condições de operação do sistema, tanto para partículas em suspensão como para CO2, comprovaram a sua eficiência na remoção de contaminantes do ambiente interior. / The use of underfloor air distribution (UFAD) systems is growing in developed countries, and this is also observed in Brazil. Besides, the interest in indoor air quality and its effects on the well being, health and productivity of the occupants in a building is an important issue nowadays. Many studies have related the advantages of UFAD systems in removing indoor air contaminants from the ambient as compared to overhead systems. In the building certification systems, they figure as good alternatives to promote better indoor air quality and thermal comfort, preserving energy efficiency, which corresponds to additional points. With the expanding interest in this technology, studies that enhance its project, keeping as a goal its global efficiency, are very welcome. The aim is to experimentally verify the contribution of an UFAD system to the indoor air quality of a classroom used by 48 students at the Civil Construction Department of the Engineering School of the University of São Paulo Brazil. The study has been conducted in a non-steady state condition. In order to perform this evaluation, the levels of indoor air-borne particles were measured at the breathing zone for seated people (1.10m from the ground), and at the exhaust (2.60m from the ground) simultaneously, under six different pre-defined values of air temperature at the occupied zone (0.60m from the ground). These concentration levels have allowed calculating the contaminant removal effectiveness index, CRE, in many points of the ambient. A similar analysis was developed for the concentrations of CO2 in the second part of the experiment. At the same time, the air temperature and air velocity were measured in six different levels and at fourteen points of the ambient. The low concentration levels of total suspension particle (under 0.035 mg/m³) have shown that this system doesn\'t disperse air contaminants indoors. The CRE indexes near or above 1.0, for both total suspension particle and CO2, have confirmed the ventilation effectiveness of this underfloor air distribution system under all the operational conditions.