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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.
441

NANDRAD 1.4 building simulation model

Paepcke, Anne 01 December 2017 (has links) (PDF)
NANDRAD is a dynamic building energy simulation program. It calulates heating/cooling requirements and electric power consumption with respect to realistic climatic conditions and dynamic room usage. The model includes one-dimensional spatially resolved heat transport through multi-layered walls and thermal storage of solid components (room furniture/building walls). Consequently, massive constructions forms in the European area are very well represented. Further, NANDRAD calculates geometrical long radiation heat exchange inside the room. Heating systems may be modeled with a high level of geometrical detail, i.e. surface heating systems as part of the wall constructions and radiant heaters inside the room. NANDRAD can be applied for passive building simulation, energy optimization and thermal comfort analysis with respect to a very detailed building representation. In this terms, the model supports the simulation of a large number of zones and walls without need for subgrouping or other model reduction strategies.
442

Etude expérimentale et numérique du traitement des ambiances par le vecteur air dans les bâtiments à très basse consommation d'énergie / Experimental and numerical study of ventilative heating and cooling in low-energy buildings

Cablé, Axel 19 April 2013 (has links)
Les bâtiments à très basse consommation d’énergie bénéficient d’une isolation thermique performante et d’une bonne étanchéité à l’air, souvent couplées à une conception bioclimatique du bâtiment. L’apport d’énergie nécessaire au chauffage et au rafraîchissement de l’ambiance s’en trouve considérablement réduit. Dans ce contexte, il devient possible d’utiliser l’air comme unique vecteur d’énergie, à des débits suffisamment faibles pour permettre son intégration dans le système de ventilation sanitaire, et avec un écart de température réduit entre l’air soufflé et l’ambiance. Une unité terminale de soufflage, ou diffuseur d’air, a alors pour rôle d’assurer un mélange optimal de l’air neuf avec l’air ambiant, de façon à obtenir une répartition homogène de température et de vitesse dans les pièces d’habitation, et un bon renouvellement de l’air intérieur. Ce travail de thèse propose une étude du confort thermique et de l’efficacité de ventilation dans une cellule climatique à échelle 1 en conditions contrôlées, dans le contexte d’utilisation d’un système combiné de ventilation, chauffage et rafraîchissement. Une stratégie de ventilation par mélange est mise en œuvre à l’aide d’un diffuseur d’air composé de douze buses lobées de géométrie complexe, et l’occupation est prise en compte par des mannequins cylindriques, qui constituent des sources de chaleur sensible et de dioxyde de carbone. La vitesse d’air, la concentration en CO2 ainsi que les températures d’air, de globe noir et des parois de la cellule sont suivies expérimentalement pour différentes conditions de soufflage d’air chaud et froid. Les mesures expérimentales sont complétées par des simulations numériques de mécanique des fluides (CFD), qui visent à caractériser l’écoulement dans la cellule. Cette approche fait intervenir une méthode de modélisation en deux temps afin d’intégrer correctement la géométrie complexe du diffuseur d’air dans les simulations. Des études paramétriques sont ensuite proposées pour des conditions non testées expérimentalement. Celles-ci visent à mettre en évidence l’impact des conditions de soufflage et des charges internes sur l’écoulement et sur le confort, pour les conditions spécifiques aux bâtiments à très basse consommation d’énergie. / Low-energy buildings benefit from a good thermal insulation and air tightness, associated with a smart integration of the building in its environment. Consequently, the required power for heating and cooling of the building is reduced to a great extent. This allows the use of conditioned ventilation air as the only energy vector: the air is supplied into the rooms at a low-velocity and with a low temperature difference with the indoor air. Air terminal devices are used, whose aim is to provide a homogeneous distribution of temperature and velocity inside of the rooms, and an efficient disposal of the indoor air pollutants. In this prospect, the thermal comfort and ventilation effectiveness in a test room (scale 1) resulting from an integrated heating, cooling and ventilation system is assessed both experimentally and numerically. The air is supplied close to the ceiling through a wall-mounted diffuser of complex geometry composed of twelve lobed nozzles, and the occupancy is modeled by two cylindrical manikins releasing sensible heat and carbon dioxide. Experimentally, the air velocity, CO2 concentration, indoor air, wall and black globe temperatures are monitored in order to assess the Predicted Mean Vote and draught rate in the occupied zone as well as the ventilation efficiency. Computational Fluid Dynamics (CFD) simulations are then performed in order to provide valuable information on the airflow patterns in the room. The air diffuser’s geometry being too complex for a direct simulation, a two-step modeling approach is adopted in order to take it into account in the simulations and to accurately represent the heat and mass transfers in the room. Furthermore, parametric studies are performed in order to investigate the influence of the supplying conditions and the internal heat gains on the airflow and on the resulting comfort, for particular conditions corresponding to those of low-energy buildings.
443

Interação animal-ambiente: efeito do ambiente climático sobre as respostas fisiológicas e produtivas de vacas Holandesas em free-stall / Animal-environment interaction: effects of climatic environment over physiologic and productive responses of Holstein cows in free-stall

Luciane Silva Martello 09 June 2006 (has links)
As relações entre os fatores climáticos e as respostas fisiológicas de vacas lactantes são bastante conhecidas, porém sob condições de ambiente controlado. Este estudo teve como objetivo monitorar as respostas dos animais em instalações típicas para vacas leiteiras, para identificar o real impacto do ambiente climático sobre o animal. Foi proposto um método para avaliar o nível de estresse de vacas, que poderá servir como uma ferramenta simples, que traduza as sensações de conforto térmico dos animais. O experimento foi realizado em três fases, a saber: primavera (28 dias), verão (31 dias) e inverno (31 dias). Foram utilizados animais da raça Holandesa com produção média entre 20 a 25 kg leite/dia. Os animais foram alojados em instalação tipo free-stall com acesso livre a um piquete adjacente. Foram avaliadas a freqüência respiratória (FR), a temperatura retal (TR), a temperatura do pelame (TPE), a temperatura auricular (TAU), a temperatura da base da cauda (TCAU), a temperatura da vulva (TVU) e a produção de leite (PL). O ambiente foi monitorado 24 horas por dia, todos os dias, com registros da temperatura de bulbo seco (TBS), da umidade relativa (UR), da temperatura de ponto de orvalho e da temperatura de globo negro (TG). Posteriormente foram calculados os índices de temperatura e umidade (ITU) e o de temperatura de globo e umidade (ITGU). Todas as variáveis fisiológicas apresentaram padrão sazonal bem claro, com maiores valores durante as estações mais quentes (primavera e verão) e menores valores no inverno. A TAU, a TVU e a TCAU apresentaram correlações positivas com a TR, a FR e a TPE, o que indica uma associação entre estas variáveis. Porém estudos adicionais devem ser conduzidos para validar a aplicabilidade destas variáveis (TAU, TVU e TCAU) na caracterização do estresse térmico dos animais. A TPE e a FR foram as variáveis mais influenciadas pelo ambiente climático em todas as estações do ano. O ambiente noturno foi associado às variações da TR, da FR e da TPE, enquanto o ambiente do dia anterior não explicou a variação das respostas fisiológicas. Não houve evidência de efeitos de uma variável ambiental isolada sobre as variáveis fisiológicas, o que indicou a complexidade das relações entre o animal e o ambiente climático. Mesmo com ITU acima de 79, considerado estressante pela literatura estrangeira para vacas lactantes, não foram evidenciados valores estressantes para TR e FR e reduções na produção de leite. O modelo proposto neste trabalho para estimar presença ou ausência de estresse em vacas alojadas em free-stall, apresentou boa aderência ao conjunto de dados, com R² de 0,43. Dessa forma, disponibiliza uma ferramenta simples e rápida para produtores e técnicos, pela associação de duas medidas fisiológicas (FR e TPE) de fácil mensuração, ou então pela associação de duas variáveis ambientais (TBS e UR). Tal ferramenta diz respeito a uma amostra da população de vacas Holandesas alojadas em determinada instalação e região, o que condiciona o modelo proposto a outros estudos para sua validação em outros rebanhos e regiões. / It has been well known the relation between the environment and physiological answers of lactating dairy cows under controlled environmental conditions. The present study aimed to monitor the animal answers allocated at typical housing system to identify the real environmental impact over it. A method was proposed to evaluate the stress level of the animal, to be used as a tool to identify the sensations of thermal comfort. The experiment was conducted in three phases, in spring (28 days), summer (31 days) and winter (31 days) periods. Holstein dairy cows were used averaging milk yield around 20 to 25 kg/day. The animals were housed in a free stall shed with an open area. Respiratory rate (FR), rectal temperature (TR), surface skin temperature (TPE), internal ear temperature (TAU), tail temperature (TCAU), vulva temperature (TVU) and milk yield (PL) were evaluated. The environmental conditions were monitored during 24 hours every day, by recording the dry bulb temperature (TBS), relative humidity (UR), dew point temperature (Tpo) and black globe temperature (Tg). The calculation of temperature humidity index (ITU) and the black globe humidity index (ITGU) was based on these environmental variables. The physiological variables had a seasonal standard with higher values during hot periods (spring and summer) and lower values during the winter. The IET, VT and TT demonstrated positive correlations with RT, RR and SKT showing association between them. More studies are necessary to validate the applicability of these variables (IET, VT and TT) and to characterize heat stress in dairy cows. SKT and RR were the most influenced by the environment in all seasons. The night environment was associated to the RT, RR and SKT, while the day before environment did not explained the physiological variations. There was no evidence of isolated environmental variables over the physiological ones, showing the complexity between the animal and the environment. Even with the THI values above 79, what is considered stressful to dairy cows, there was no evidence of stressful values for RT and RR and of MY losses. The model proposed in this study to estimate presence or absence of heat stress in dairy cows avails a simple and fast tool to milk producers and technicians, where it could be associated two physiological variables (RR and SKT) of easy measurement or other two environment variables (DBT and RH). However, this result is related to the studied population at a specific housing system and situated at a specific region. Addiitonal studies must be conducted to validate the proposed model to others dairy herds and locations.
444

Bioclimatologia subtropical e modelização do conforto humano: da escala local à regional / Subtropical bioclimatology and modelling of human comfort: from local to regional scales

Gobo, João Paulo Assis 23 November 2017 (has links)
O objeto desta pesquisa consiste em avaliar e propor índices de conforto térmico humano por meio de variáveis ambientais, subjetivas e individuais, em escala climática local e regional. Para tanto, parte-se da hipótese de que o estudo abrangente do conforto térmico humano em escala local, por meio de entrevistas e análise do tempo in-loco, forneceria subsídios para o desenvolvimento de um índice que transite até a escala regional do clima. Parte-se, então, de um método indutivo experimental (levantamento em campo de variáveis climáticas, individuais e subjetivas) onde foram feitas coletas em campo no período de agosto de 2015, janeiro e julho de 2016, com a aplicação de questionários à população simultâneos a coleta de dados meteorológicos. Os resultados do estudo apontaram para a determinação da influência das particularidades climáticas regionais no conforto e na sensação térmica das pessoas entrevistadas, por meio dos efeitos diretos do clima regional. Confirmou-se a existência da influência do sexo dos indivíduos em relação às suas respostas de sensação térmica, bem como a influência dos aspectos fisiológicos tais como o índice de massa corporal e a faixa etária, na preferência térmica dos destes entrevistados. O presente estudo também possibilitou a calibração das faixas interpretativas de conforto térmico de diferentes índices de conforto para a área de estudo. Foram propostos quatro índices de conforto humano com base nas variáveis ambientais, subjetivas e individuais locais, sendo um índice exclusivo para a situação de verão, outro calculado para o inverno, um terceiro índice desenvolvido para ambas as situações sazonais (verão e inverno) e um quarto índice, também para ambas as situações sazonais, porém, tendo como variáveis de partida apenas a temperatura do ar, da umidade relativa do ar e da velocidade do vento. Por fim, foram avaliadas estatisticamente a abrangência espacial e a extrapolação da escala de análise dos resultados para um dos índices desenvolvidos, propondo a validação deste para a escala climática regional. Os resultados apresentados possibilitaram a avaliação do conforto humano, das variáveis ambientais, subjetivas e individuais, bem como o desenvolvimento de um índice adequado tanto para escala local quanto para a escala regional do clima, o que conferiu uma resposta conclusiva à hipótese central apresentada. / This research aims to evaluate and propose human thermal comfort indexes using environmental, individual and subjective variables in the local and regional climatic scales. For that, the hypothesis tested is that the comprehensive study of human thermal comfort, by means of interviews and in-situ weather analysis, provides the basis for the development of an index suitable to be applied also in the regional climatic scale. The first step in the research consisted of an experimental inductive method of field data collection of climatic, individual and subjective variables. Data was collected in the periods of August 2015, January and July of 2016, with questionnaires being applied to the population simultaneously to the collection of meteorological data. Results point to the influence of regional climatic characteristics over the thermal comfort of interviewed individuals, through the direct effects of regional climatic conditions. The influence of gender in thermal comfort responses was confirmed, as well as physiological aspects such as Body Mass Index and age group, in the thermal preference of interviewed individuals. This study also made it possible to calibrate different human thermal comfort classes for the different comfort indexes used in the area of study. Four human thermal comfort indexes were proposed based on environmental, subjective and individual local variables. One index was calculated for Summer, another for Winter, and a third index was developed for both seasons. A fourth index was also calculated for both seasons but using only air temperature, relative humidity and wind speed as variables. Lastly, the spatial representativeness and scale extrapolation of the results for one of the developed models were evaluated statistically in order to propose its validation to the regional climatic scale. Results present the evaluation of human thermal comfort and environmental, subjective and individual variables, as well as the development of an index suitable for both local and regional climatic scales, which provided an appropriate answer to the central hypothesis presented.
445

Estudio comparativo del efecto en el confort térmico de los pavimentos asfálticos y de concreto con diatomita en microclimas con ENVI-met / Comparative study of the effect in thermal comfort of asphalt and concrete with diatomite pavements with ENVI-met

Basurto Villafuerte, Jean Paul Luis, Chirinos Hurtado, Carlos Arturo 14 December 2020 (has links)
El presente artículo evalúa de manera comparativa el confort térmico en el uso de los pavimentos asfalticos frente a los pavimentos de concreto con adición de diatomita. La variable que se considerará para el estudio será la reflectancia. Para la comparación se utilizará el software ENVI-met donde se modelará zonas de Lima identificadas como Islas de Calor (UHI) que usen pavimentos asfalticos las cuales, en el modelo, serán reemplazadas por pavimentos de concreto con adición de diatomita y se obtendrá el confort térmico de todos los modelos por el método PET a través del programa ya mencionado. Finalmente se comparará dichos resultados. / This article comparatively evaluates the thermal comfort in the use of asphalt pavements versus concrete pavements with the addition of diatomite. The variable that will be considered for the study will be reflectance. For the comparison, the ENVI-met software will be used where areas of Lima that use asphalt pavements identified as Heat Islands (UHI) will be used, which will be replaced by concrete pavements with diatomite and thermal comfort will be seen by the PET method through of the aforementioned program. Finally, those results will be compared. / Trabajo de investigación
446

Wärmeabgabe teilbeheizter Fußböden

Kremonke, André 13 June 2000 (has links)
Mit Hilfe von experimentellen Untersuchungen wird nachgewiesen, daß sich die nutzerseitig abgegebene Wärmestromdichte des außenwandnahen Fußbodenbereiches nicht allein über die Differenz zwischen der Heizflächen- und Raumtemperatur beschreiben läßt. Die Ableitung verallgemeinerbarer Berechnungsansätze ist Schwerpunkt der Arbeit. Die experimentellen Untersuchungen erfolgen in einem Modellraum in Originalgröße. Meßtechnisch erfaßt werden die Oberflächentemperaturen, die Lufttemperaturverteilung, die Luftgeschwindigkeitsverteilung und die örtliche Gesamtwärmestromdichte der beheizten Fußbodenbereiche. Der konvektive Wärmeübergang wird maßgeblich von der über dem Fußboden umgelenkten Falluftströmung an der Außenwand beeinflußt. Zur Berechnung der örtlichen Maximalgeschwindigkeiten wird ein einfacher Berechnungsansatz entwickelt. Mit Hilfe numerischer Untersuchungen erfolgt ein Vergleich verschiedener Heizsysteme hinsichtlich der Empfindungstemperaturverteilung.
447

Databáze tepelných parametrů oblečení pro systém iHVAC / Drivers clothing thermal resistance database for iHVAC system

Hrubanová, Kristýna January 2017 (has links)
This diploma thesis is focused on measurement of thermal properties of clothes by thermal manikin and on application of results for prediction of thermal comfort in system iHVAC. First part of thesis is dedicated to research with relation to this topic and to definitions of main computational equations necessary for experimental measurement. The choise of method for measurement based on available standards is an important part of this thesis. The main focus of thesis lies on measuring 5 combinations of clothes at different calibration temperatures and same temperature of manikin surface. Then data are examined and also the analysis of uncertaities and repeatability is maked. According to assupmtion , the independence of value of heat transfer coefficient to ambient temperature is comfirmed and calculated heat resistance of every single clothes is compared to existing wardrobe for system iHVAC. The outcome of this thesis is specificied and completed virtual wardrobe which serves to prediction of thermal comfort in car.
448

Pobytové místnosti a kvalita vzduchu / Residential rooms and air quality

Valkovič, Michal January 2018 (has links)
The master thesis solves indoor air quality in hotel rooms based on CO2 levels. The first part deals with indoor climate of buildings, where each form of indoor climate is described separately. The experimental part deals with CO2 level measurement in residual room, air infiltration through window and their analysis. The last part of thesis deals with results of the experiment, which are used to design and optimize hygienic ventilation, based on acquisition costs and operating expenses.
449

Větrací systém automobilu - porovnání vlivu okrajových podmínek na proudění z různých typů vyústek / Automotive ventilation system - comparison of an influence of boundary conditions on flow from various types of ventilation outlets

Brdečko, Radim January 2020 (has links)
Diploma thesis deals with a research of the flow in front of three different automotive vents. The velocity field and intensity of the turbulence was measured in detail, using thermoanemometry. After that the same data was measured with PIV method and validation was performed. The difference between achieved data was investigated. The design among the vents was also investigated, because it’s fundamentally affects the air flow. The purpose of this thesis is to obtain data about the velocity field using two methods and their subsequent use to validate numerical simulations, which will be performed in the future. The diploma thesis also contains the calculation of measurement uncertainty.
450

Tepelný komfort a jeho stanovení / Thermal comfort and its estimation

Žáková, Monika January 2015 (has links)
This paper summarizes the problems of human thermoregulation and its measurement, with a focus on the method of indirect calorimetry in resting conditions at different ambient temperatures and during physical activity. It also introduces the issue of human thermal comfort and the methodology of its monitoring using thermal manikin. It describes PowerCube Ergo (Ganshorn, Germany) and Cardiovit AT-104 (Schiller, Switzerland), the diagnostic devices used to spiro-ergometry measurements. It introduces the options to export data. The work proposes the protocol for measuring the thermoregulation of the small group of volunteers, which is realized by the practical part. According to the same protocol is monitored thermal comfort of the thermal manikin. In MATLAB is created the application, allowing clear analysis of measurement records. The data are evaluated and discussed.

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