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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.
71

Moderní energie a snížení energetické náročnosti budov / Modern energy and decreasing the energy intensiveness of buildings

Kučera, Miroslav January 2009 (has links)
This diploma thesis deals with possible energy-savings in the municipal buildings of Spytihněv. Moreover, it discusses the possible improvements of heating features and making use of renewable resources. This is meant to be achieved by a wrapper which is less demanding on energy consumption than those which have been used until now. Attention is also paid to a more efficient system of energy distribution. Both energetic and financial points of view are taken into consideration. The thesis consists of a few parts. Introduction, the first part, deals with renewable resources issues on a theoretical level. The second part is divided according to each individual analysed premise/building. At this point energy-saving proposal, choice of a heating system, a heating pump, a solar collector as well as energy-saving and financial calculation are included.
72

Värmeförluster i fjärrvärmerör : En granskning av värmeförluster i fjärrvärmerör / Heat losses in district heating pipes : A study of heat losses in district heating pipes

Behnam, Majd, Karlsson, Axel January 2017 (has links)
Den här examensarbete är en utredning av värmeförluster och ekonmiska besparingar av olika fjärrvärmerör. En fiktiv fjärrvärmeförläggning på 100m, för respektive dimension av fjärrvärmerör, har legat till grund för beräkningarna. Syftet är att få en klar bild på hur lönsamt det är att använda sig utav isoleringsserie 3 istället för isoleringsserie 2 alternativt dubbelrör med isoleringsserie 2 när förutsättningar tillåter detta.Resultaten visar att dubbelrör i mindre dimensioner har en lägreinvesteringskostnad, har lägre värmeförluster och ger en större vinst än vad enkelrör serie 2 och serie 3. För dubbelrör i större dimensioner så är investeringskostnaderna något högre men värmeförlusterna mycket lägre.I jämförelsen mellan serie 2 och serie 3 så är serie 3 lönsamt i båda fallen.Dessa resultat visar att det gynnar fjärrvärmenätägare i längden att använda sig utav en högre isoleringsserie alternativt dubbelrör.Examensarbetet har ej utrett miljöpåverkan av respektive rör, ej heller har kontirör undersökts. / This thesis is an evaluation of heat losses and economical savings for different types of district heating pipes. Calculations have been based on a fictional district heating system with the length 100m, for each district heating pipe dimension. The cause is to get a clear image of how profitable it is to use a higher series of insulation alternatively using twin pipes when it’s possible.The results show that twin pipes in lower dimensions has a lower investment cost, less heat losses and is more profitable than insulation series 2 and series 3. When it comes to twin pipes with a higher dimension the investment cost is slightly higher than single pipe insulation series 3, though the heat losses are much lower.The comparison between series 2 and series 3 show that series 3 is more profitable in both cases.These results show that it’s profitable for the network owners in the long-term to use either a higher insulation series or twin pipes.No evaluation of neither the impact on the environment or district heating pipes with diffusion barrier, has been done.
73

Vorstudie zu wertbeeinflussenden Parametern hinsichtlich der Klimaeffizienz von Wohngebäuden

Soot, Matthias, Dingerdissen, Ulrike, Eltner, Anette, Flatt, Holger, Fast, Harry, Loges, Sören, Ostrau, Stefan, Paffenholz, Jens-André, Weitkamp, Alexandra 18 October 2022 (has links)
Der Immobiliensektor trägt maßgeblich zur Treibhausgasemission bei und muss daher in den kommenden Jahren wesentlich verändert werden, um die notwendigen Einsparungen zu erzielen. Im Rahmen dieses Beitrags werden erste Untersuchungen dargestellt, den Wohnimmobilienmarkt mittels verschiedener Geosensoren zu erfassen, um aus den visuell erfassbaren Eigenschaften sowie geometrischen Informationen von Gebäuden Aussagen zu energetischen Zuständen von Immobilien zu tätigen. Dazu ist im Zuge eines Kooperationsprojekts der TU Dresden, der TU Clausthal, dem Fraunhofer IOSB-INA sowie der Geoinformationsbehörde des Kreises Lippe und dem Gutachterausschuss für Grundstückswerte im Kreis Lippe und in der Stadt Detmold eine Messkampagne durchgeführt worden. Im Rahmen dieser Messkampagne wurde eine Begehung durch Immobilienexperten sowie eine terrestrische und drohnenbasierte Erfassung mit RGB-Bildern, Laserscanning und Wärmebildern eines Quartiers durchgeführt. Die erfassten Eigenschaften von Immobilien werden in diesem Beitrag qualitativ diskutiert, um das mögliche Potenzial für eine automatisierte Bewertung des energetischen Zustands abzuschätzen. Durch empirische Untersuchungen sollen darüber hinaus die Werteinflüsse von energetischen Sanierungen auf die Verkehrswerte der Immobilien quantifiziert werden. Diese Information kann genutzt werden, um in etwaigen Förderprogrammen die Differenz zwischen den zu tätigenden Investitionen und dem dadurch hervorgerufenen Wertzuwachs zu fördern. In der vorliegenden Untersuchung kann gezeigt werden, dass Einschätzungen von Immobilienexperten zur Qualität von Immobilien zu guten Ergebnissen führen. Die genutzten Sensoren sind geeignet, Qualitäten und Schwächen von Immobilien aufzudecken, jedoch müssen die zeitlichen Konfigurationen der Aufnahmen optimiert werden.
74

Автоматизация расчета теплопотерь здания с использованием его цифровой информационной модели : магистерская диссертация / Automation of calculation of heat loss of a building using its digital information mode

Точилкин, Д. С., Tochilkin, D. S. January 2024 (has links)
Диссертация посвящена разработке программного скрипта, позволяющего автоматизировать процесс расчета теплопотерь здания с использованием его цифровой информационной модели. В рамках работы рассмотрены основные понятия для расчета теплопотерь, проведен анализ существующего ПО и описан алгоритм работы разработанного программного продукта. / The dissertation is devoted to the development of a software script that allows you to automate the process of calculating the heat loss of a building using its digital information model. As part of the work, the basic concepts for calculating heat loss are considered, the analysis of existing software is carried out and the algorithm of operation of the developed software product is described.
75

Phenotypic variation and thermoregulation of the human hand

Payne, Stephanie January 2018 (has links)
The hand has the highest surface area-to-volume ratio of any body part. This property offers the potential for the hand to serve an important function in thermoregulation through radiative heat loss. Theoretically, the capacity for heat loss may be influenced by hand and digit proportions, but the extent to which these proportions influence the hand's radiative properties remains under-investigated. Although hand morphology is highly constrained by both integration and functional dexterity, phenotypic variation in hand and digit proportions across human populations shows broad ecogeographic patterns. These patterns have been associated with climate adaptation. However, the theory linking climate adaptation to such ecogeographic patterns is based on underlying assumptions relating to thermodynamic principles, which have not been tested in vivo. This study sought to determine the influence of hand and digit proportions on heat loss from the hands directly, the additional anthropometric factors that may affect this relationship, and the impact of variation in hand proportions on dexterity in the cold. The relationship between hand proportions and thermoregulation was tested through both laboratory-based investigation and a field study. The laboratory investigation assessed the relationship between hand proportions and heat loss, the influence of body size and composition on this relationship, and the effect of morphological variation on manual dexterity. Participants (N=114; 18-50 years of age), underwent a 3-minute ice-water hand-immersion. Thermal imaging analysis was used to quantify heat loss. Hand and digit proportions were quantified using 2D and 3D scanning techniques; body size and composition were measured using established anthropometric methods and bio-impedance analysis. After accounting for body size, hand width, digit-to-palm length ratio, and skeletal muscle mass were significant predictors of heat loss from the hand, whilsthand length and fat mass were not. A separate set of participants (N=40) performed a Purdue pegboard dexterity test before and after the immersion test, which demonstrated that digit width alone negatively correlated with dexterity. The field study tested whether phenotypic variation in upper limb proportions could be attributed to cold adaptation or selection for dexterity in living populations exposed to significant energetic stress. Upper limb segment lengths were obtained from participants (N=254; 18-59 years of age), from highland and lowland regions of the Nepalese Himalayas using established anthropometric methods, and relative hand proportions were assessed in relation to severe energetic stress associated with life at high altitude. Relative to height, hand length and hand width were not reduced with altitude stress, whilst ulna length was. This indicates that cold adaptation is not shaping hand proportions in this case, although phenotypic variation in other limb segments may be attributed to cold adaptation or a thrifty phenotype mechanism. The current study provides empirical evidence to support the link between surface area-to-volume ratio, thermodynamic principles and ecogeographical patterns in human hand morphology. However, this research also demonstrates the complexity of the hand's role in thermoregulation; not only do other factors such as muscularity affect heat loss from the hand, but hand morphology is also highly constrained by integration and dexterity.
76

Development of a four-phase thermal-chemical reservoir simulator for heavy oil

Lashgari, Hamid Reza 16 February 2015 (has links)
Thermal and chemical recovery processes are important EOR methods used often by the oil and gas industry to improve recovery of heavy oil and high viscous oil reservoirs. Knowledge of underlying mechanisms and their modeling in numerical simulation are crucial for a comprehensive study as well as for an evaluation of field treatment. EOS-compositional, thermal, and blackoil reservoir simulators can handle gas (or steam)/oil/water equilibrium for a compressible multiphase flow. Also, a few three-phase chemical flooding reservoir simulators that have been recently developed can model the oil/water/microemulsion equilibrium state. However, an accurate phase behavior and fluid flow formulations are absent in the literature for the thermal chemical processes to capture four-phase equilibrium. On the other hand, numerical simulation of such four-phase model with complex phase behavior in the equilibrium condition between coexisting phases (oil/water/microemulsion/gas or steam) is challenging. Inter-phase mass transfer between coexisting phases and adsorption of components on rock should properly be modeled at the different pressure and temperature to conserve volume balance (e.g. vaporization), mass balance (e.g. condensation), and energy balance (e.g. latent heat). Therefore, efforts to study and understand the performance of these EOR processes using numerical simulation treatments are quite necessary and of utmost importance in the petroleum industry. This research focuses on the development of a robust four-phase reservoir simulator with coupled phase behaviors and modeling of different mechanisms pertaining to thermal and chemical recovery methods. Development and implementation of a four-phase thermal-chemical reservoir simulator is quite important in the study as well as the evaluation of an individual or hybrid EOR methods. In this dissertation, a mathematical formulation of multi (pseudo) component, four-phase fluid flow in porous media is developed for mass conservation equation. Subsequently, a new volume balance equation is obtained for pressure of compressible real mixtures. Hence, the pressure equation is derived by extending a black oil model to a pseudo-compositional model for a wide range of components (water, oil, surfactant, polymer, anion, cation, alcohol, and gas). Mass balance equations are then solved for each component in order to compute volumetric concentrations. In this formulation, we consider interphase mass transfer between oil and gas (steam and water) as well as microemulsion and gas (microemulsion and steam). These formulations are derived at reservoir conditions. These new formulations are a set of coupled, nonlinear partial differential equations. The equations are approximated by finite difference methods implemented in a chemical flooding reservoir simulator (UTCHEM), which was a three-phase slightly compressible simulator, using an implicit pressure and an explicit concentration method. In our flow model, a comprehensive phase behavior is required for considering interphase mass transfer and phase tracking. Therefore, a four-phase behavior model is developed for gas (or steam)/ oil/water /microemulsion coexisting at equilibrium. This model represents coupling of the solution gas or steam table methods with Hand’s rule. Hand’s rule is used to capture the equilibrium between surfactant, oil, and water components as a function of salinity and concentrations for oil/water/microemulsion phases. Therefore, interphase mass transfer between gas/oil or steam/water in the presence of the microemulsion phase and the equilibrium between phases are calculated accurately. In this research, the conservation of energy equation is derived from the first law of thermodynamics based on a few assumptions and simplifications for a four-phase fluid flow model. This energy balance equation considers latent heat effect in solving for temperature due to phase change between water and steam. Accordingly, this equation is linearized and then a sequential implicit scheme is used for calculation of temperature. We also implemented the electrical Joule-heating process, where a heavy oil reservoir is heated in-situ by dissipation of electrical energy to reduce the viscosity of oil. In order to model the electrical Joule-heating in the presence of a four-phase fluid flow, Maxwell classical electromagnetism equations are used in this development. The equations are simplified and assumed for low frequency electric field to obtain the conservation of electrical current equation and the Ohm's law. The conservation of electrical current and the Ohm's law are implemented using a finite difference method in a four-phase chemical flooding reservoir simulator (UTCHEM). The Joule heating rate due to dissipation of electrical energy is calculated and added to the energy equation as a source term. Finally, we applied the developed model for solving different case studies. Our simulation results reveal that our models can accurately and successfully model the hybrid thermal chemical processes in comparison to existing models and simulators. / text
77

Estudo da produção de calor metabólico em caprinos manejados no semi-árido nordestino / Metabolic heat production in goats managed in semiarid region

Domingos, Hérica Girlane Tertulino 21 May 2012 (has links)
Made available in DSpace on 2016-08-15T20:31:12Z (GMT). No. of bitstreams: 1 HericaGTD_DISSERT.pdf: 597617 bytes, checksum: 59784d911ca59573a589df402958dde5 (MD5) Previous issue date: 2012-05-21 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study aimed to assess the daily variation of metabolic heat production in goats based on oxygen consumption and carbon dioxide production in association with meteorological variables and physiological responses. 10 SPRD goats were used, four with predominantly white fur and six with predominantly black. The observations were made with the protected and exposed animals to direct sunlight, in a period of 12 days during the months of August and September, 2010 in Mossoró-RN. The metabolic heat production (M, Wm-2), the latent heat flow from the respiratory system (ER, Wm-2) and from the cutaneous surface (ESC Wm-2) were determined simultaneously through a face mask and a ventilated capsule, respectively. We also measured the rectal temperature, surface temperature and respiratory rate and measured the environmental variables, air temperature, black globe temperature, wind speed, air humidity, partial vapor pressure and solar radiation. Analysis of variance was based on least-squares method and comparison of means was done by Tukey's test at 5% level of significance. The results showed that the semi-arid goats maintained stable to metabolic heat production during the day, however, when exposed to direct sunlight, significantly increased the latent heat loss in the cutaneous surface and reduced metabolic heat production approximately 24% in an attempt to maintain constant internal temperature / Este estudo objetivou avaliar a variação diária da produção de calor metabólico em caprinos baseada no consumo de oxigênio e produção de dióxido de carbono em associação com variáveis meteorológicas e respostas fisiológicas. Foram utilizados 10 caprinos SPRD, sendo quatro com pelame predominantemente branco e seis com pelame predominantemente preto. As observações foram feitas com os animais protegidos e expostos à radiação solar direta, em um período de 12 dias, durante os meses de agosto e setembro de 2012, em Mossoró-RN. A produção de calor metabólico (M, Wm-2), o fluxo de calor latente a partir do sistema respiratório (ER, Wm-2 ) e a partir da superfície cutânea (ESC, Wm-2) foram determinados, ao mesmo tempo, por meio de uma máscara facial e uma cápsula ventilada, respectivamente. Foram também aferidas a temperatura retal, temperatura de superfície e a freqüência respiratória e medidas as variáveis ambientais, temperatura do ar, temperatura do globo negro, e velocidade do vento, pressão parcial de vapor, e radiação solar. A análise de variância foi baseada no método dos quadrados mínimos e a comparação de médias foi feita pelo teste de Tukey com nível de 5% de significância. Os resultados mostraram que as cabras do semi-árido brasileiro mantiveram estável a produção de calor metabólico ao longo do dia, no entanto, quando expostas a radiação solar direta, aumentaram consideravelmente a perda de calor latente na superfície cutânea e reduziram a produção de calor metabólico em aproximadamente 24%, numa tentativa de manter a temperatura interna constante
78

Termorregulação e produção de ovos de galinhas Label Rouge em ambiente equatorial semiárido / Thermorregulation and egg production of Label Rouge hens in an equatorial semi-arid environment

Souza Jr, João Batista Freire de 24 February 2014 (has links)
Made available in DSpace on 2016-08-15T20:31:17Z (GMT). No. of bitstreams: 1 JoaoBFSJ_DISSERT.pdf: 848742 bytes, checksum: 5da6694c94e2b15db5ab8ba10f875e9a (MD5) Previous issue date: 2014-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate the effect of corn particle size on performance, egg quality and sensible heat loss, beyond of the regional differences in surface temperature of naked neck laying hens by infrared thermography. In Mossoró-RN, 60 label Rouge chickens in laying stage were distributed in a completely randomized design, where were fed with diets containing different corn particle size or geometric mean diameter (GMD) of 605 µm, 1030 µm and 2280 µm. Environmental variables were measured in center of the shed: black globe temperature (TG) and air (TA), wind speed (U) and relative humidity (RH). Rectal temperature (RT), respiratory rate (RR) and surface temperature (TS) were measured in each bird once a week. For sensible heat loss, RT, RR and TS, the analysis of variance was performed by least squares method and comparison of means by Tukey's test (p<0.05). The results showed that the GMD 2280 µm increased the feed intake, causing elevation in body temperature and respiratory rate in response to increased metabolic heat production. The hens fed with this same GMD showed lower quality eggshell. The sensible heat transfer was, during the study, a heat dissipation mechanism, where the increase in radiation and TA levels caused significant decrease in heat loss by radiation, but heat loss by convection was high in high TA due to increased wind speed. There are regional differences in the TS, where the legs act as thermal windows / Objetivou-se com este estudo avaliar as diferenças regionais na temperatura superficial através de imagens térmicas e o efeito do ambiente semiárido e do tamanho da partícula do milho no desempenho, qualidade do ovo e perda de calor sensível de poedeiras do pescoço pelado. Em Mossoró-RN, 60 galinhas da linhagem Label Rouge em fase de postura foram distribuídas em um delineamento inteiramente casualizado, onde foram fornecidas rações com diferentes tamanhos da partícula do milho ou diâmetro geométrico médio (DGM) de 605 µm, 1030 µm e 2280 µm. As variáveis ambientais foram aferidas no centro do galpão: temperatura do globo negro (TG) e do ar (TA), velocidade do vento (U) e umidade relativa (UR). A temperatura retal (TR), frequência respiratória (FR) e temperatura superficial (TS) foram aferidas em cada ave uma vez por semana. Para a perda de calor sensível, TR, FR e TS a análise de variância foi realizada pelo método dos quadrados mínimos e a comparação de médias para todas as variáveis pelo teste de Tukey (p<0.05). Os resultados mostraram que o DGM igual a 2280 µm aumentou o consumo de ração, causando elevação na temperatura corporal e frequência respiratória como resposta à maior produção de calor metabólico. As aves alimentadas com este mesmo DGM apresentaram qualidade da casca do ovo inferior. A transferência de calor sensível apresentou-se com um mecanismo de dissipação térmica, onde o aumento nos níveis de radiação e TA causaram diminuição significativa na perda de calor por radiação, mas a convecção foi elevada em alta TA devido ao aumento na movimentação do ar. Houve diferença regional na TS, onde as patas atuaram como janelas térmicas
79

Návrh vytápění a větrání pro „Emotivní dům“ / Heating and ventilation in the „Emotivní dům“

Brázda, Jan January 2017 (has links)
This master’s thesis deals with the design of the heating and ventilation system for the ‘Emotivní dům’ which was designed by the author of this thesis. The first part of the thesis provides an overview of the project and the architectural design of the house. In the next part, the calculation of the heat loss and the design of the heating and ventilation system is described. War-air heating/ventilation is used in in the habitable rooms of the house with the hydronic system utilized in other spaces. The floor heating is used in the bathrooms and the other non-habitable spaces, such as the garage, are heated with radiators. A natural gas boiler is used as a heat source for both space heating and domestic hot water heating. The thesis contains the floor plans of the house as well as technical drawings of the heating and ventilation system.
80

Energetický posudek a PENB při výměně zdroje tepla v rodinném domě / Energy Assessment and PENB when Replacing Heat Source in a Family House

Minář, David January 2018 (has links)
The diploma thesis deals with energy assessment and proof of energy performance of the building when replacing the heat source in a family house. The theoretical part deals with thermography and thermocamera in energy practice. The experimental part of the thesis was focused on the thermographic survey of the object and the evaluation of the outputs. The computational part focuses on the energy analysis of the assessed energy economy.

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