In the residential and commercial buildings, most of the energy is used to provide the thermal comfort environment to the occupants. The recent research towards Green Buildings is focusing on reduction of energy consumption by air-conditioners and fans used for producing the thermal comfort environment. The thermal comfort is defined as the condition of mind which expresses human satisfaction with the thermal environment. The human body is continuously producing metabolic heat and it should be maintained within the narrow range of core temperature. The heat generated inside the body should be lost to the environment to maintain the thermal equilibrium with each other. The heat loss from the body is taking place in different modes such as conduction, convection, radiation and evaporation through the skin and respiration. These heat losses are influenced by the environmental factors (air temperature, air velocity, relative humidity and mean radiant temperature), physiological factors (activity level, posture and sweat rate) and clothing factors (thermal insulation value, evaporative resistance and microenvironment volume). When the body is in thermally equilibrium with its surrounding environment, the heat production should be equal to heat loss to maintain the thermal comfort. The level of thermal comfort can be measured by the different indices which combine many parameters. Of these, the Fanger’s PMV (Predicted Mean Vote) – PPD (Percentage of People Dissatisfied) index was universally suggested by ASHRAE and ISO. The PMV – PPD index was derived based on the experiment conducted on acclimated European and American subjects. Many researchers have criticized that the PMV – PPD index is not valid for tropical regions and some researchers have well agreed with this index for the same region. The validation of PMV – PPD index for thermal comfort Indians has not yet been examined. The validation of PMV – PPD index can be done by the human heat balance experiment and the individual heat losses have to be calculated from the measured parameters. In the human heat balance, the convective heat transfer plays the major role when the air movement exists around the human body. The convective heat loss is dependent on the convective heat transfer coefficient which is the function of the driving force of the convection. Using Computational Fluid Dynamics techniques, an attempt has been made in this work to determine the convective heat transfer coefficient of the human body at standing posture in natural convection. The CFD technique has been used to analyze the heat and fluid flow around the human body as follows: The anthropometric digital human manikin was modeled in GAMBIT with a test room. This model was meshed by tetrahedral elements and exported to FLUENT software to perform the analysis. The simulation was done at different ambient temperatures (16 oC to 32 oC with increment of 2 oC). The Boussinesq approximation was used to simulate the natural convection and the Surface to Surface model was used to simulate the radiation. The surrounding wall temperature was assigned equal to the ambient temperature. The sum of convective and radiative heat losses calculated based on the ASHRAE model was set as heat flux from the manikin’s surface. From the simulation, the local skin temperatures have been taken, and the temperature and velocity distributions analyzed. The result shows that the skin temperature is increasing with an increase in ambient temperature and the thickness of the hydrodynamic and thermodynamic boundary layers is increasing with height of the manikin. From the Nusselt number analogy, the convective heat transfer coefficients of the individual manikin’s segments have been calculated and the relation with respect to the temperature differences has been derived by the regression analysis. The relation obtained for the convective heat transfer coefficient has been validated with previous experimental results cited in literature for the same conditions. The result shows that the present relation agrees well with the previous experimental relations. The characteristics of the human thermal plume have been studied and the velocity of this plume is found to increase with the ambient temperature. Using the Grashof number, the flow around the human manikin has been examined and it is observed to be laminar up to abdomen level and turbulent from shoulder level. In between these two levels, the flow is found to be in transition. The validation of PMV model for tropical countries, especially for Indians, was done by heat balance experiment on Indian subjects. The experiment was conducted on forty male subjects at different ambient temperatures in a closed room in which low air movement exists. The local skin temperature, relative humidity, air velocity and globe temperature were measured. The sensation vote was received from all the subjects at all the conditions. The convective heat loss was calculated from its coefficient obtained from the present computational simulation. The radiation heat loss was calculated for two cases: In case one, the mean radiant temperature was taken equal to the ambient temperature and in case two, the mean radiant temperature was calculated from the globe temperature. The other heat losses were calculated from the basic formulae and the relations given by ASHRAE based on Fanger’s assumption. From these calculations, the validity of the Fanger’s assumption was examined. The collected sensation votes and the calculated PMV were compared to validate the PMV – PPD index for Indians. The experimental results show that there was much variation in the calculated comfort level using the measured parameters and the Fanger’s assumption. For the case of mean radiant temperature equal to the ambient temperature for indoor condition, the comfort level was varying more than the actual. In addition, the calculated comfort level from the globe temperature agreed well with the comfort level from the collected sensation votes. So it was concluded that the ASHRAE model is valid for Indians if the radiation was measured exactly. Using the ASHRAE model, the required wall emissivity of the surrounding wall at different ambient temperatures was determined from the CFD simulation. In the ASHRAE model, the surrounding wall emissivity plays the major role in the radiative heat loss from the human body. Hence in recent years, research on low emissive wall paints is focused. The computational study was done to determine the required wall emissivity to obtain the thermal comfort of the occupant at low energy consumption. The simulation was done with the different ambient temperatures (16 oC to 40 oC with increment of 4 oC) with the different surrounding wall emissivity (0.0 to 1.0 with increment of 0.2). From this simulation, the change in mean skin temperature with respect to wall emissivity was obtained for all ambient temperature conditions. The required mean skin temperature for a particular activity level was compared with the simulation results and from that, the required wall emissivity at the different ambient conditions was determined. If the surrounding walls are having the required emissivity, it leads to decrease in heat/cold strain on the human body, and the thermal comfort can be obtained with low energy consumption.(please note that title in the CD is given as COMPUTATION OF REQUIRED WALL EMISSIVITY FOR LOW ENERGY CONSUMPTION IN BUILDINGS USING ASHRAE MODEL VALIDATED FOR INDIAN THERMAL COMFORT)

Diplomová práce je zaměřena na měření ventilovaného sedadla s ohledem na tepelný komfort člověka. Popisuje a shrnuje tepelný přenos lidského těla s okolím a termoregulaci člověka. Dále zachycuje a zhodnocuje vybrané přístupy hodnocení tepelného komfortu. Zabývá se komplexním přehledem tepelně komfortních jednotek v automobilu. Představuje použitou metodu měření tepelného komfortu u ventilovaného sedadla, načež analyzuje a vyhodnocuje jednotlivá získaná data.

Desde a introdução do conceito de escritório aberto, o tipo de ocupação e a distribuição das cargas internas têm sofrido grandes mudanças, requerendo maior flexibilidade nos edifícios. Além disto, avaliações de desempenho de edifícios de escritórios da atualidade têm apresentado resultados que são fortes indicadores da necessidade de mudanças de conceitos de projeto, operação e uso de sistemas de condicionamento de ar, devido ao elevado nível de insatisfação dos usuários quanto ao conforto e à qualidade do ar. Para tentar solucionar estes problemas, outro conceito em distribuição de ar, já em uso nos países desenvolvidos, está começando a ser adotado também no Brasil; trata-se de insuflamento pelo piso, com difusores instalados em placas de piso elevado e nas estações de trabalho, que permitem flexibilidade e controle individual de vazão de ar. Neste trabalho foi feita a avaliação de sistema de condicionamento de ar com insuflamento pelo piso em um laboratório com condições controladas. O laboratório em que foram realizados os ensaios foi projetado e instalado com características similares àquelas de ambientes reais de edifícios de escritórios. Este fato, aliado à participação de usuários no processo de avaliação das condições de conforto térmico, tornaram possível a definição de parâmetros para a elaboração de projetos bem como para o estabelecimento de um modo eficaz de operação do sistema. O processo de avaliação das condições de conforto térmico no ambiente envolveu três etapas. Inicialmente, foram feitas medições das variáveis de conforto térmico no ambiente e de variáveis do sistema utilizando simuladores. Posteriormente, foi realizada a avaliação subjetiva do conforto térmico, com a substituição dos simuladores por pessoas no ambiente (usuários), nas mesmas condições da etapa anterior. Finalmente, foram feitas as medições das variáveis de conforto nas zonas de ocupação – micro climas – na condição de condicionamento individualizado, promovido por ajustes de vazão de ar e direcionamento do fluxo pelos usuários. Os resultados da avaliação permitem concluir que o sistema de condicionamento de ar com insuflamento pelo piso atende às expectativas para promover conforto térmico aos usuários de edifícios de escritórios com potencial de conservação de energia. / Since the introduction of the landscape office concept, the layout type and the internal loads distribution have changed significantly, requesting larger flexibility in the buildings. Besides, building performance evaluation applied to contemporary office buildings has shown that for most such buildings thermal comfort and air quality users level satisfaction is low. These facts are indicating that project concepts, operation and use of air conditioning systems need to be changed. In order to solve these problems, underfloor air supply is becoming a common practice also in Brazil. This system with floor and workstation diffusers allows flexibility and an individualized airflow control. In this work the evaluation of the underfloor air conditioning system was carried out in a laboratory facility with controlled conditions. The laboratory was designed and built up with similar characteristics to those of actual office buildings environments. This fact and the participation of users in the process of thermal comfort evaluation, made possible the definition of design parameters as well as the establishment of the system operation conditions in an effective way. The evaluation of the environment thermal comfort conditions was accomplished in three stages. Initially, measurements of thermal comfort and system variables were made using simulators. Later, in the same conditions of the previous stage, users (a sample of people) have evaluated, in a subjective way, the environment thermal comfort. Finally, measurements of the comfort variables were accomplished in the occupation areas - microclimates - in the condition of individualized conditioning, promoted by air flow adjustments and flow direction by the users. The results of the evaluation allow to conclude that the underfloor air conditioning system satisfies to the expectations to promote thermal comfort to the office building users with potential of energy conservation.

Desde a introdução do conceito de escritório aberto, o tipo de ocupação e a distribuição das cargas internas têm sofrido grandes mudanças, requerendo maior flexibilidade nos edifícios. Além disto, avaliações de desempenho de edifícios de escritórios da atualidade têm apresentado resultados que são fortes indicadores da necessidade de mudanças de conceitos de projeto, operação e uso de sistemas de condicionamento de ar, devido ao elevado nível de insatisfação dos usuários quanto ao conforto e à qualidade do ar. Para tentar solucionar estes problemas, outro conceito em distribuição de ar, já em uso nos países desenvolvidos, está começando a ser adotado também no Brasil; trata-se de insuflamento pelo piso, com difusores instalados em placas de piso elevado e nas estações de trabalho, que permitem flexibilidade e controle individual de vazão de ar. Neste trabalho foi feita a avaliação de sistema de condicionamento de ar com insuflamento pelo piso em um laboratório com condições controladas. O laboratório em que foram realizados os ensaios foi projetado e instalado com características similares àquelas de ambientes reais de edifícios de escritórios. Este fato, aliado à participação de usuários no processo de avaliação das condições de conforto térmico, tornaram possível a definição de parâmetros para a elaboração de projetos bem como para o estabelecimento de um modo eficaz de operação do sistema. O processo de avaliação das condições de conforto térmico no ambiente envolveu três etapas. Inicialmente, foram feitas medições das variáveis de conforto térmico no ambiente e de variáveis do sistema utilizando simuladores. Posteriormente, foi realizada a avaliação subjetiva do conforto térmico, com a substituição dos simuladores por pessoas no ambiente (usuários), nas mesmas condições da etapa anterior. Finalmente, foram feitas as medições das variáveis de conforto nas zonas de ocupação – micro climas – na condição de condicionamento individualizado, promovido por ajustes de vazão de ar e direcionamento do fluxo pelos usuários. Os resultados da avaliação permitem concluir que o sistema de condicionamento de ar com insuflamento pelo piso atende às expectativas para promover conforto térmico aos usuários de edifícios de escritórios com potencial de conservação de energia. / Since the introduction of the landscape office concept, the layout type and the internal loads distribution have changed significantly, requesting larger flexibility in the buildings. Besides, building performance evaluation applied to contemporary office buildings has shown that for most such buildings thermal comfort and air quality users level satisfaction is low. These facts are indicating that project concepts, operation and use of air conditioning systems need to be changed. In order to solve these problems, underfloor air supply is becoming a common practice also in Brazil. This system with floor and workstation diffusers allows flexibility and an individualized airflow control. In this work the evaluation of the underfloor air conditioning system was carried out in a laboratory facility with controlled conditions. The laboratory was designed and built up with similar characteristics to those of actual office buildings environments. This fact and the participation of users in the process of thermal comfort evaluation, made possible the definition of design parameters as well as the establishment of the system operation conditions in an effective way. The evaluation of the environment thermal comfort conditions was accomplished in three stages. Initially, measurements of thermal comfort and system variables were made using simulators. Later, in the same conditions of the previous stage, users (a sample of people) have evaluated, in a subjective way, the environment thermal comfort. Finally, measurements of the comfort variables were accomplished in the occupation areas - microclimates - in the condition of individualized conditioning, promoted by air flow adjustments and flow direction by the users. The results of the evaluation allow to conclude that the underfloor air conditioning system satisfies to the expectations to promote thermal comfort to the office building users with potential of energy conservation.

This dissertation deals with the measurement of the internal environment through thermal manikin Newton, especially in terms of thermal comfort. Measurements were performed in a typical office environment and cabins of small transport aircraft. The course of events and the time constants for the measurement in the office was given by real flow in the office when the sequences of events were unfolded from the usual transactions carried out during the day. In contrast, the second measurement, which took place in the model of small transport aircraft, the course of events and time constants, was performed exactly according to predetermined plan. The other parts of the thesis describe how to calibrate the manikin and then generate a diagram comfort zones. Following are compared individual test cases and events using the diagram comfort zones. Finally, individual test cases and events are compared using the diagram comfort zones and medics according to ISO 14505-2.

Master of Science / Department of Architecture / R. Todd Gabbard / This research aims to explore and assess passive solar design techniques that promote high thermal comfort in vernacular houses of the state of Jharkhand in India. The study of these houses provides useful insights for designing energy efficient houses that provide thermally comfortable conditions. An analysis of these houses in Ranchi, the capital city of Jharkhand, India provides a context for the field research. Jharkhand predominantly has two different styles of vernacular houses: huts and havelis. These houses were constructed, without any mechanical means, in such a manner as to create micro-climates inside them to provide high thermal comfort levels. Hence the study of thermal comfort levels in these buildings in relation to built environment in today's context is significant. As part of data collection, interviews were conducted with the occupants of ten houses in Ranchi, in June 2007. Two houses of each (huts and havelis) were selected for detailed experimental analysis. Experiment results indicated that all the four selected houses exhibited lower ambient temperature than outside during the day and a higher ambient temperature at night. Brick bat coba and lime mortar were the key materials used for constructing high thermal-mass walls. Adequate ventilation is significant in creating conditions that are comfortable. Aperture to volume ratio of less than 0.051 is not adequate enough to cool the thermal mass of these houses. These houses also use attic space to mitigate the heat gain from the roof. Courtyards and other exterior spaces form an integral part of these houses and influence the thermal conditions in and around the houses. The case studies show that there is a scope for more relaxation of comfort temperature range based on culture and phenomenon of acclimatization. A universal approach in understanding and defining comfort condition fails because the users of these houses were comfortable in conditions defined as uncomfortable by ASHRAE and Nicol.

Buildings, especially in hot climates, consume a lot of energy when people want to be comfortable inside them, which translates to very expensive fees each month. The most innovative response to this problem is renewable energy, that is used, in this case, to run mechanical HVAC systems. Renewable energy is the solution for many problems, but to avoid urban heat islands when using excessive HVAC systems (powered by renewables), and to solve thermal comfort-related problems, there has to be other solution. The major challenge to find it would be to have a change of thinking process. If a building in a hot-arid region uses natural processes to emulate the functions of HVAC systems, and the proper passive strategies, then, it will provide thermal comfort to its users, diminishing the need of a mechanical system. This hypothesis will be carried out by extracting the natural processes found in a specific case in nature, applying them into a building's design, and then simulating its energy efficiency with the adequate software. There will be a comparison of the same proposed building without the natural processes, to have tangible numbers showing that these proposed strategies, in fact, work. With explanatory detailed diagrams and the energy analysis, the hypothesis could be proven correct or incorrect. The significance of this approach relies on the proximity to the natural processes that have been working in different aspects of life since the beginning of time. They have been there all the time, waiting until architects, engineers, and people in general use them, instead of making more new energy-using inventions. By having the numbers from a conventional building and the ones of the proposed building, and the right environmental diagrams, the experiment should be valid. In the near future, there should be more research focused on nature and its processes, in order to be able to reduce the use of mechanical systems, and with that, reduce the energy use and the carbon footprint.

This thesis presents an investigation into the viability of Low Energy Earth Pipe Cooling Technology in providing thermal comfort in Malaysia. The demand for air-conditioning in buildings in Malaysia affects the country escalating energy consumption. Therefore, this investigation was intended to seek for a passive cooling alternative to air-conditioning. By reducing the air-conditioning demand, there would be a higher chance of Malaysia government to achieve their aim in reducing CO2 emissions to 40 per cent by the year 2020, compared to 2005 levels. The passive technology, where the ground was used as a heat sink to produce cooler air, has not been investigated systematically in hot and humid countries. In this work, air and soil temperatures were measured on a test site in Kuala Lumpur. At 1m underground, the result is most significant, where the soil temperature are 6oC and 9oC lower than the maximum ambient temperature during wet and dry season, respectively. Polyethylene pipes were buried around 0.5m, 1.0m and 1.5m underground and temperature drop between inlet and outlet were compared. A significant temperature drop was found in these pipes: up to 6.4oC and 6.9oC depending on the season of the year. The results have shown the potential of Earth Pipe in providing low energy cooling in Malaysia. A parametric study on the same experiment was carried out using Energy Plus programme. Energy Plus data agreed with the field work data and therefore, this confirms Energy Plus is reliable to investigate Earth Pipe Cooling in Malaysia. Furthermore, thermal comfort of air at the Earth Pipe outlet was analyzed and the result has shown that the outlet air is within the envelope of thermal comfort conditions for hot/humid countries

Skin temperature plays an important role in human thermoregulation together with core temperature. Skin temperature varies to a large extent across the body and this is especially pronounced in cold environments. The variations of skin temperature are also involved in the generation of regional thermal perceptions that can lead to behavioural adjustments. Whilst the temporal and inter-individual variations of skin temperature have been well studied using contact sensors, the knowledge of spatial variations has received less attention in the literature. Infrared thermography is a specific imaging technique particularly valuable for the exploration of the topography or pattern of skin temperature across the body. Most research using this technique has only been case studies or experiments focused in one specific body region. However, extensive regional skin temperature data over the whole-body can be proven useful for different types of applications including the sport clothing industry in combination with other body-mapping data. The primary aim of this thesis was to develop an original and standardised method using infrared thermography enabling whole-body skin temperature data to be compared for the assessment of spatial, temporal and inter-individual variations. A specific methodology for infrared data collection and data processing was successfully developed in order to combine data from a variety of participants varying in anthropometrical characteristics. The main outcomes were the production of several skin temperature body maps, either absolute maps to show the magnitude of the temporal or inter-individual effects, and normalised maps (relative to mean skin temperature) allowing for topographical comparisons between protocol stages, populations or interventions. The second aim of the thesis was to extend the understanding of the skin temperature patterns and how these could relate with thermal perceptions. The body-mapping method gave the opportunity to investigate a large amount of conditions, where various internal or external determinants of skin temperature were be involved. This was mainly done in cool to cold environments (5°C to 20°C) where skin temperature is not uniform but is associated with local and overall comfort. Studies were firstly performed in semi-nude conditions (Chapter 3, 4, 5) and then in clothed conditions (Chapter 6 and 7). The semi-nude studies were designed to explore the potential sexdifferences in regional skin temperature responses whilst running (Chapter 3) with a special interest in the role of skinfold thickness, this was further extended with a group of males at rest having a large variety of fat content and thickness (Chapter 4). The influence of exercise type and air temperature on skin temperature patterns was studied with a rowing exercise (Chapter 5). Studies were then performed in clothed conditions (Chapter 5, 6). The influence of real-life conditions on skin temperature patterns and associated perceptual responses was observed during a hiking scenario (Chapter 6). Following these descriptive studies, manipulation of skin temperature patterns was performed using clothing in order to determine the presence of any relevant effect on thermal comfort (Chapter 7). Our results demonstrated that the skin temperature pattern over the whole-body is relatively universal with several features being consistently found regardless of the conditions or the populations. The upper body is usually warmer than the lower body and the body creases (orbital, elbow regions etc.) are also warmer than surrounding regions. A Y-shape of colder temperatures has been highlighted over the anterior torso as well as a T- or Y-shape of warmer temperature over the posterior torso. There are yet some specificities that can be displayed due to active muscles during exercise such as the warmer skin overlying the trapezius and biceps muscles in rowing (Chapter 5), the influence of the backpack construction with up to 3°C warmer skin temperature in the lower back (Chapter 6) or the importance of additional clothing insulation minimizing the anterior Y-shape of colder skin temperatures (Chapter 7). Beyond the thermal patterns, absolute skin temperature differences have been observed between sexes with females displaying 2°C colder skin during semi-nude running (Chapter 3) and 1°C colder skin during clothed walking (Chapter 6)compared to males. The skin temperature difference can also be as large as 6°C colder skin for an obese male compared to a very lean male (40% vs 7% body fat). Despite these differences, there were almost no significant differences in overall and regional thermal sensations and comfort between sexes or between males with varying body fat. Our results focused on body fat revealed that overall fat content and sum of skinfolds was inversely associated with the mean skin temperature response during various protocols (Chapter 4, 6, 7). Local skinfold thickness explained the inter-individual variability of local skin temperature for resting (Chapter 4) and exercising males (Chapter 7) in most body regions. In terms of intra-individual variations, the distribution of skinfold thickness across the anterior torso explained the distribution of skin temperature in this segment solely in conditions with strong regional contrasts (Chapter 3, 4 and 7). When the whole-body skin temperature pattern is considered, our body-mapping approach failed to show relationships between skin temperature distribution across the body and regional skinfold thickness distribution neither at rest nor during exercise. The relative contribution of other internal determinants such as local heat production,local blood flow distribution and local anthropometry should be further investigated to fully elucidate the spatial skin temperature variations depending on the climate, clothing and the body thermal state. Lastly, there was a trend towards improved thermal comfort during rest and exercise in the cold through a manipulation of skin temperature patterns targeting the naturally cold body regions with high insulation, therefore obtaining a more homogeneous skin temperature distribution across the body (Chapter 7). The present work will benefit the sport goods industry. The descriptive results of skin temperature variations will be useful in order to validate multi-segmental model of human thermoregulation. Further work can include pattern predictions for exercise types and conditions not covered by the present thesis. The skin temperature maps will mainly feed the general body-mapping approach for clothing design taking into account several other body mapping data such as sweat mapping and the combination of cold, warm and wetness sensitivity mappings. Lastly, the present results have highlighted the interest for targeted solutions and also the need for more evolutive systems in the field of cold weather apparel.

This studyh focuses on thermal comfort and cost effectiveness of stratum ventilation in subtropical Hong Kong Special Adminstation Region (HKSAR). The need for studying thermal comfort with various air distribution strategies becomes a significant issue recently due to climate change, increasing energy prices and the governmental energy efficiency policy. Stratum ventilation, with air supplied at breathing level, can probably provide satisfactory thermal comfort at a relatively elevated indoor temperature in which less energy use is consumed. It seems that only limited studies on the evaluation of neutral temperature, which is a condition of neither slightly warm nor slightly cool, are supported by actual human comfort surveys. Moreover, study on the related thermal comfort and cost effectiveness as other paradigms in comparison with the mixing and displacement air distribution design is rare. New environmental chamber of laboratory-based air-conditioning systems has been developed for investigating the actual benefit of cost effectiveness and balance of thermal comfort satisfaction with the stratum air distribution strategy under subtropical climates. American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 7-point questionnaires have been collected from human comfort tests so as to estimate the neutral temperature of stratum ventilation in comparison with mixing and displacement ventilation at pre-set conditions. The neutral temperatures of HKSAR people under the mode of mixing, displacement, stratum, modified-stratum-1, modified-stratum-2, and modified-stratum-3 are found to be 24.6℃, 25.1℃, 25.6℃, 26.0℃, 27.1℃ and 27.3℃ at 10 air change per hour (ACH) respectively, which become 24.8℃, 25.3℃, 26.6℃, 27.4℃, and 27.9℃ at 15 ACH respectively. Life cycle assessment results in 10 service year indicate that 7.73% and 7.32% of cost reduction, and 14.52% and 11.91% of greenhouse gas emission reduction in stratum ventilation by comparing with mixing and displacement ventilation. As a result, stratum ventilation should be the best option on both of cost reduction, and less carbon emission in small-to-medium size air-conditioned space for new building and retrofitting existing works.