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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.
1

Multi-sector thermophysiological head simulator for headgear research

Martínez Guillamón, Natividad 07 March 2016 (has links)
[EN] Predicting thermal comfort perceived during wearing protective clothing is important especially for the head as it is one of the most sensitive body parts to heat. Since helmets typically induce an additional thermal insulation that impairs the heat dissipation from the head, a special attention should be drawn to a heat strain leading to a decrease of the cognitive performance and to adverse health effects. Thermal manikins allow systematic analysis of the heat and mass transfer properties of protective clothing. However, this methodology does not provide sufficient information about the local and the whole body human physiological response in different cases of use. The prediction of the physiological state of the body is provided by a thermophysiological model. However, they are not capable of accounting for complex heat and mass exchange processes at the skin surface when the clothing is worn. Thermal devices could measure the overall effect of these processes when wearing the given actual gear and being exposed to the surrounding environment. Several attempts to couple thermal manikins with physiological models have been undertaken, however, the partial coupling of a body part manikin with a physiological model has not been addressed so far. Hence, the aim of this work was to develop a novel thermophysiological human head simulator for headgear evaluation based on the coupling of a thermal head manikin with a thermophysiological model. This method would be able to realistically reproduce the effect of clothing on the heat and mass transfer from the head's skin to the environment. A thermal head manikin with a dedicated segmentation for headgear testing was evaluated for the thermophysiological human head simulator. This head manikin showed consistent when compared to previously published data of a less segmented head manikin and the more detailed investigation of the local heat transfer at head brought additional information regarding the contribution of the local design characteristics of the headgear to the overall heat exchange. The thermal head manikin was evaluated in the most demanding scenarios according to the human physiology. It was possible to consistently define four head parts, namely, forehead, cranial, face and neck parts. When heterogeneous surface temperature distribution was applied on the head manikin, the gradients between head parts could compromise the precision of skin temperature prediction at forehead and face. The passive heating and cooling responsiveness of the head manikin did not present any limitation for simulating sudden temperature step changes. However, when the manikin heating and cooling processes were modulated by the PI control with default settings, the time needed to reach the temperature set point was larger than the time required by the human physiology. The thermophysiological model was validated for prediction of global and local skin temperatures by comparing simulations against human experimental data in a wide range of conditions. The physiological model showed a good precision in general when predicting core and mean skin temperature. A reduced precision was observed for some local skin temperatures. Finally, the thermal head manikin and the physiological model were coupled to build up the thermophysiological head simulator. The comparison of the prediction of the coupled system with human experimental data in several scenarios showed a good agreement for rectal and mean skin temperatures. However, some greater discrepancy was observed for forehead temperature in exposures in which participants were exercising in warm environments. The representation of the human sweat evaporation could be affected by a reduced evaporation efficiency and manikin sweat dynamics. The industry will benefit from this thermophysiological human head simulator, which will lead to the development of helmet designs with enhanced thermal comfort, and therefore, with higher acceptance by users / [ES] Poder predecir el confort térmico durante el uso de indumentaria de protección es muy relevante especialmente en el caso de la cabeza, ya que es una de las partes más sensibles del cuerpo al calor. Los cascos y otros elementos de protección frente a impactos incorporan un aislamiento adicional que di-ficulta la disipación de calor en la cabeza. Los maniquís térmicos permiten analizar de manera sistemática las propiedades de transferencia de calor y humedad de la indumentaria de protección. Sin embargo, esta metodología no permite inferir la respuesta fisiológica del usuario cuando utiliza la prenda. Existen modelos termofisiológicos que permiten predecir la respuesta térmica humana pero presentan algunas limitaciones cuando se representan los procesos de transferencia de calor y humedad a través de la ropa. En este caso, un maniquí térmico podría cuantificar el intercambio real de calor que se pro-duce con el ambiente térmico cuando se viste una determinada prenda. Existen experiencias en las que un maniquí de cuerpo completo ha sido acoplado con un modelo termofisiológico. Sin embargo, el acoplamiento de un maniquí que representa únicamente una parte del cuerpo con un modelo de la fisiología humana no ha sido llevado a cabo hasta ahora. Por lo tanto, el objetivo de este trabajo ha sido desarrollar una nueva metodología para evaluar cascos y equipos de protección para la cabeza basándose en el acoplamiento de un maniquí térmico de cabeza con un modelo fisiológico. Un maniquí térmico de cabeza ha sido evaluado para ser acoplado con un modelo termofisiológico. Sus medidas fueron consistentes con resultados anteriormente publicados realizados con un maniquí en menos seccionado. Este nuevo maniquí introdujo información adicional sobre la contribución en particular de las distintas características de diseño del casco al intercambio de calor global. El maniquí térmico de cabeza fue evaluado en los escenarios más extremos identificados para la fisiología humana. Se pudo identificar cuatro partes en el sistema acoplado, frente, cráneo, cara y cuello. En el caso de simular una distribución heterogénea de temperatura, los gradientes generados entre las diferentes partes podrían comprometer la precisión en la predicción de la temperatura de la piel en la frente y la cara. La capacidad pasiva de calentamiento y enfriamiento del maniquí de cabeza no supuso ninguna limitación para simular los cambios súbitos de temperatura de la piel pero cuando el control PI del maniquí moduló los procesos de calentamiento y enfriamiento, el tiempo necesario para alcanzar la temperatura de consigna fue mayor que el tiempo de reacción observado en la fisiología humana. Las predicciones de temperatura obtenidas con el modelo de la fisiología humana fueron validadas mediante la comparación con datos humanos experimentales. En general, el modelo mostró buena precisión para la predicción de la temperatura interna y la temperatura media de la piel. Sin embargo, la precisión observada fue menor para la predicción de algunas temperaturas locales. El maniquí térmico de cabeza y el modelo termofisiológico fueron acoplados. La comparación de las predicciones del sistema acoplado con datos humanos experimentales en diferentes escenarios mostró concordancia para la temperatura rectal y media de la piel. No obstante, se observó una mayor discrepancia en la predicción de la temperatura de la frente si se comparaba las simulaciones obtenidas con el modelo por sí solo y con el sistema acoplado en escenarios en los que los participantes realizaban actividad física ambientes cálidos. La representación de la evaporación del sudor humano en el sistema acoplado podría estar condicionada por una menor eficiencia en la evaporación y la respuesta dinámica de la sudoración del maniquí. La industria se podrá beneficiar de este sistema para avanzar en el desarrollo de nuevos productos que proporcionen / [CAT] Poder predir el confort tèrmic durant l'ús d'indumentària de protecció es especialment rellevant en el cas del cap, ja que és una de les parts més sensibles del cos a la calor. Els cascs incorporen un aïllament adicional que dificulta la dissipació de la calor al cap. Aquest fet és particularment dramàtic quan l'estrès tèrmic afecta negativament a la funció cognitiva i té efectes negatius sobre la salut. Els maniquins tèrmics permeten analitzar de manera sistemàtica les propietats tèrmiques de la indumentària de protecció. No obstant, aquesta metodologia no permet inferir la resposta fisiològica de l'usuari quan utilitza la indumentària. En l'actualitat existixen models matemàtics que permeten predir l'estat fisiològic del cos humà però presenten algunes limitacions quan es tracta de simular els complexos processos de transferència de calor i humitat que ocorren amb roba. En aquest cas, un maniquí tèrmic podria quantificar l'intercanvi real de calor que es produïx en l'ambient tèrmic quan es porta una determinada roba. Existixen experiències prèvies en les que un maniquí de cos complet ha sigut acoblat en un model de la fisiologia humana. No obstant, l'acoblament d'un maniquí que representa únicament una part del cos en un model de la fisiologia humana no ha sigut dut a terme fins ara. Per tant, l'objectiu d'aquest treball es desenvolupar una nova metodologia per a evaluar cascs i indumentària de protecció per al cap basada en l'acoblament d'un maniquí tèrmic de cap amb un model fisiològic. Un maniquí tèrmic de cap ha sigut valorat per a ser acoplat en un model de la fisiologia humana. Les mesures del maniquí van ser consistents amb els resultats publicats en maniquís menys seccionats. Aquest maniquí tèrmic de cap introduix informació adicional sobre la contribució particular de les dife-rents característiques del disseny dels cascs a l'intercanvi de calor global. El maniquí tèrmic de cap ha sigut valorat en els escenaris més extrems identificats per la fisiologia hu-mana. Es van poder identificar quatre parts al sistema acoblat, front, crani, cara i coll. En el cas de simular una distribució heterogènia de temperatura en la superfície del maniquí de cap, els gradients generats entre les diferents parts podria comprometre la precisió en la predicció de la temperatura de la pell en el front i la cara. La capacitat passiva de calfament i refredament del maniquí de cap no va suposar ninguna limitació per simular els canvis sobtats de temperatura de la pell observats en la fisiologia humana. No obstant, quant el control PI del maniquí modulà els processos de calfament i refredament, el temps necessari per alcançar la temperatura de consigna va ser major que el temps de reacció observat en la fisiologia humana. Les prediccions de temperatura obtingudes en el model de la fisiologia humana previst per formar part del sistema acoblat van ser validades amb dades humanes experimentals. En general, el model va mostrar una bona precisió en la predicció de la temperatura interna i la temperatura mitjana de la pell. No obstant, la precisió va ser menor en la predicció de las temperaturas locals. El maniquí tèrmic de cap i el model de la fisiologia humana van ser acoblats. La comparació de les prediccions del sistema acoblat amb dades humanes experimentals mostraren concordança en el cas de la temperatura rectal i mitjana de la pell. No obstant, s'observà una major discrepància en la predicció de la temperatura del front quant es comparaven les simulacions obtingudes en el model per sí mateix i el sistema acoblat en escenaris en els quals els participants realitzaven activitat física en am-bients càlids. La representació de l'evaporament del suor humà en el sistema acoblat podria estar con-dicionada per una menor eficiència en l'evaporament. La indústria es podra beneficiar d'aquest sistema per a avançar en el desenvolupament de nous productes que proporcione / Martínez Guillamón, N. (2016). Multi-sector thermophysiological head simulator for headgear research [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61487 / TESIS
2

Characterization of Lamps of IRF Solar Simulator

Sonna, Mrunmayee January 2023 (has links)
The Swedish Institute of Space Physics (IRF) at Kiruna focuses on research activities in the ionosphere, magnetosphere, and upper atmosphere of the planet as well as the development and production of various sensors and detectors for space research. The test facility includes the IRF SpaceLab which is equipped with multiple testing equipment. One of the testing resources available is the Solar Simulator, which consists of a vacuum chamber equipped with four metal halide lamps that produce a spectrum closely resembling that of the Sun. When any spacecraft payload or instrument is exposed to the Sun and its radiations, the most important factors to consider are the type of radiation, flux, and how the exposed material will react. Thermal designing and solar balance tests are important factors in achieving expected conditions for different missions. By testing and verifying these lamps, this solar simulator can be used not only for IRF missions but also for other institutes and private organizations that can access it. The characterization of four lamps is done in terms of temperature distribution, radiation, and power. According to preliminary experimental measured values obtained from the setup, exposed material, and its properties can be varied and the best suitable coating can be selected that includes α (absorptivity) and ϵ (emissivity) valueconsideration. The thesis is divided into four phases: Designing, Manufacturing, Testing, and Analyzing. Before entering into these phases, the basic knowledge of thermal engineering and thermal simulation is acquired. Thermal modeling and simulations are done in Airbus Defence & Space’s Systema Thermica software tool. The design phase includes designing a frame structure and a 350 x 350 mm screen in Autodesk Inventor software. Manufacturing of the frame structure and the screen was done in the IRF workshop. This screen kept hanging with the support of a frame structure which is mounted on the copper table inside the chamber. The screen is kept in the field of view of each lamp and every lamp is illuminated accordingly. The analysis is done by measuring the temperature of the back side of the screen. Temperature sensors were mounted and clamped mechanically instead of kapton tape to avoid direct contact with the screen. The obtained values are analyzed and compared with the thermally simulated values. Pressure and the temperature of the system were monitored with independent systems throughout the test procedure. This thesis report could operate as a foundation for future examination of the solar simulator’s lamps in order to determine precise efficiency.
3

Effect of welding thermal cycles on the heat affected zone microstructure and toughness of multi-pass welded pipeline steels

Nuruddin, Ibrahim K. January 2012 (has links)
This research is aimed at understanding the effect of thermal cycles on the metallurgical and microstructural characteristics of the heat affected zone of a multi-pass pipeline weld. Continuous Cooling Transformation (CCT) diagrams of the pipeline steel grades studied (X65, X70 and X100) were generated using a thermo mechanical simulator (Gleeble 3500) and 10 mm diameter by 100 mm length samples. The volume change during phase transformation was studied by a dilatometer, this is to understand the thermodynamics and kinetics of phase formation when subjected to such varying cooling rates. Samples were heated rapidly at a rate of 400°C/s and the cooling rates were varied between t8/5 of 5.34°C/s to 1000°C/s. The transformation lines were identified using the dilatometric data, metallographic analysis and the micro hardness of the heat treated samples. Two welding processes, submerged arc welding (SAW) and tandem Metal Inert Gas (MIG) Welding, with vastly different heat inputs were studied. An API-5L grades X65, X70 and X100 pipeline steels with a narrow groove bevel were experimented with both welding processes. The welding thermal cycles during multi-pass welding were recorded using thermocouples. The microstructural characteristics and metallurgical phase formation was studied and correlated with the fracture toughness behaviour as determined through the Crack Tip Opening Displacement (CTOD) tests on the welded specimens. It was observed that SAW process is more susceptible to generate undesirable martensite-austenite (M-A) phase which induce formation of localised brittle zones (LBZ) which can adversely affect the CTOD performance. Superimposition of the multiple thermal cycles, measured in-situ from the different welding processes on the derived CCTs, helped in understanding the mechanism of formation of localised brittle zones. Charpy impact samples were machined from the two X65 and X70 grades, for use in thermal simulation experiments using thermo mechanical simulator (Gleeble). The real thermal cycles recorded from the HAZ of the SAW were used for the thermal simulations, in terms of heating and cooling rates. This is to reproduce the microstructures of the welds HAZ in bulk on a charpy impact sample which was used for impact toughness testing, hardness and metallurgical characterisation. The three materials used were showing different response in terms of the applied thermal cycles and the corresponding toughness behaviours. The X65 (a) i.e. the seamless pipe was showing a complete loss of toughness when subjected to the single, double and triple thermal cycles, while the X65 (b), which is a TMCP material was showing excellent toughness in most cases when subjected to the same thermal cycles at different test temperatures. The X70 TMCP as well was showing a loss of toughness as compared to the X65 (b). From the continuous cooling transformation diagrams and the thermally simulated samples results it could be established that different materials subjected to similar thermal cycle can produce different metallurgical phases depending on the composition, processing route and the starting microstructure.
4

Simulação numérica de blocos e prismas de alvenaria em situação de incêndio / Numerical simulation of masonry blocks and prisms under fire situation

Rodovalho, Francielle da Silva 23 May 2018 (has links)
A alvenaria estrutural é um sistema construtivo muito antigo no qual as paredes exercem função estrutural além da função de vedação. Este sistema construtivo é muito utilizado no Brasil, entretanto, poucas pesquisas foram realizadas sobre o seu comportamento em situação de incêndio e o país ainda não possui métodos normativos de dimensionamento de alvenaria estrutural em situação de incêndio. Assim, o objetivo deste trabalho foi verificar o desempenho da alvenaria estrutural com blocos de concreto submetida a elevadas temperaturas através da simulação de prismas. No software Abaqus foram simulados o comportamento do bloco e prisma sujeitos à compressão em temperatura ambiente e do prisma em situação de incêndio com diferentes condições de contorno. O comportamento do bloco e prisma sujeitos à compressão e em temperatura ambiente foi validado até a carga última. As elevações de temperatura das faces não expostas ao fogo ficaram bem representadas por meio das simulações térmicas. A perda de resistência dos materiais foi adotada conforme a literatura técnica nas simulações termomecânicas. Através do que foi analisado no trabalho observou-se que os prismas se comportam bem quanto ao isolamento térmico em situação de incêndio, principalmente aquele com revestimento em argamassa nas duas faces. Quanto ao critério de resistência mecânica os resultados numéricos não foram validados com experimentais, entretanto, foi possível representar a deterioração térmica dos materiais. / The structural masonry is a very old building system in which the walls have structural and partition function. The use of this building system is widely spread in Brazil, however, few research programs were carried out on their behavior under fire situation and the country has not yet developed standard normative methods for designing structural masonry subject to fire. Thus the purpose of this research was to verify the performance of concrete blockwork structural masonry submitted to high temperatures through the simulation of prisms. In the Abaqus software the behavior of block and prism subjected to compression at room temperature and of the prism under fire situation with different boundary conditions were simulated. The compression of the block and prism at room temperature was validated until ultimate loads. The temperature rises of the non-exposed faces were well represented through thermal simulations. The material\'s resistance loss was adopted according to the technical literature in the thermomechanical simulations. Based on the analyzed examples it was observed that the prisms behave well regarding the thermal insulation under fire situation, mainly when having mortar coating on both sides. Regarding the mechanical resistance criterion, the numeric results were not validated with experimental ones, however, it was possible to represent the thermal deterioration of the materials.
5

Simulação numérica de blocos e prismas de alvenaria em situação de incêndio / Numerical simulation of masonry blocks and prisms under fire situation

Francielle da Silva Rodovalho 23 May 2018 (has links)
A alvenaria estrutural é um sistema construtivo muito antigo no qual as paredes exercem função estrutural além da função de vedação. Este sistema construtivo é muito utilizado no Brasil, entretanto, poucas pesquisas foram realizadas sobre o seu comportamento em situação de incêndio e o país ainda não possui métodos normativos de dimensionamento de alvenaria estrutural em situação de incêndio. Assim, o objetivo deste trabalho foi verificar o desempenho da alvenaria estrutural com blocos de concreto submetida a elevadas temperaturas através da simulação de prismas. No software Abaqus foram simulados o comportamento do bloco e prisma sujeitos à compressão em temperatura ambiente e do prisma em situação de incêndio com diferentes condições de contorno. O comportamento do bloco e prisma sujeitos à compressão e em temperatura ambiente foi validado até a carga última. As elevações de temperatura das faces não expostas ao fogo ficaram bem representadas por meio das simulações térmicas. A perda de resistência dos materiais foi adotada conforme a literatura técnica nas simulações termomecânicas. Através do que foi analisado no trabalho observou-se que os prismas se comportam bem quanto ao isolamento térmico em situação de incêndio, principalmente aquele com revestimento em argamassa nas duas faces. Quanto ao critério de resistência mecânica os resultados numéricos não foram validados com experimentais, entretanto, foi possível representar a deterioração térmica dos materiais. / The structural masonry is a very old building system in which the walls have structural and partition function. The use of this building system is widely spread in Brazil, however, few research programs were carried out on their behavior under fire situation and the country has not yet developed standard normative methods for designing structural masonry subject to fire. Thus the purpose of this research was to verify the performance of concrete blockwork structural masonry submitted to high temperatures through the simulation of prisms. In the Abaqus software the behavior of block and prism subjected to compression at room temperature and of the prism under fire situation with different boundary conditions were simulated. The compression of the block and prism at room temperature was validated until ultimate loads. The temperature rises of the non-exposed faces were well represented through thermal simulations. The material\'s resistance loss was adopted according to the technical literature in the thermomechanical simulations. Based on the analyzed examples it was observed that the prisms behave well regarding the thermal insulation under fire situation, mainly when having mortar coating on both sides. Regarding the mechanical resistance criterion, the numeric results were not validated with experimental ones, however, it was possible to represent the thermal deterioration of the materials.
6

Elektro-termální model a simulace integrovaného obvodu / Electro-thermal model and simulation of integrated circuit

Sikora, Martin January 2020 (has links)
Thermal effects in integrated circuits have increasing impact on chip's lifetime and function. For this reason, the chips must be subjected to electro-thermal simulations prior to the launch of production in order to avoid potential circuit failures. Therefore, in the first part of this diploma thesis these effects and methods of creating thermal models are described. The thesis also explores available tools for electro-thermal simulations and the way these simulators work. In the practical part of the thesis, the operation of electro-thermal simulation in the Eldo tool is verified, a method of automated thermal network creation is proposed and a application for its generation based on the circuit layout is implemented. The results of the electro-thermal simulation with the generated thermal network are compared with the results of the currently used method.
7

Comparative assessment of two structural materials from a life-cycle point of view : Using dynamic and LCA calculation units from LESOSAI

Matricon, Geoffrey January 2015 (has links)
Life-cycle assessment is being applied to an increasing number of building projects from one side while the usual dynamic thermal simulations are being conducted from the other side on the same projects. However, there are few observations in the literature linking these two types of calculations: embodied and operating energies are rarely directly compared. This paper compares those energies for some case studies. The challenge is to quantify to what extent chosen structural materials can change their global life-cycle energy balance. This question is raised by the different dynamic thermal behavior of materials. Consequently, the case studies focus on the influence of materials’ thermal mass on the operating energy consumptions.Nonetheless, few software programs can conduct both these calculations (LCA and dynamic thermal modeling). The Swiss regulatory tool LESOSAI has been implemented and offers now these two possibilities. However, its LCA database is arcane, this paper will first assess the LCA results of LESOSAI by comparing it with the French tool ELODIE developed by the CSTB. Measuring the reproducibility of their results provides boundaries to the LCA calculations that LESOSAI can perform. These identified limits enable to set the starting assumptions of the case studies. Two raw materials are compared: wood and concrete structures. Considering thermal mass as a dynamic property, different typologies of building usages and climates have been investigated for the materials comparisons. Finally, the conclusion emphasizes the material that permits the lowest life-cycle impact for each typology and climate.
8

Low-Temperature Thermal Control System for an Environmental Chamber

Lindemanis, Aleksis Pauls January 2022 (has links)
In spite of significant reduction of cost associated with launching a spacecraft, launching deep space exploratory missions are yet to be accessible to most universities and researchers. A solution to testing scientific hypotheses and verifying technologies for space is the use of environmental chambers, also know as space simulators, - vacuum chambers, which replicate the space environment. The scope of this thesis project is to develop a thermal control system for a space simulator, which would replicate the environment on Mars, and allow for controlled carbon dioxide ice deposition experiments. The first part of the thesis looks at the climate on Mars, and the process behind the carbon dioxide ice cycle, gives a description of the systems in a space simulator. Then the requirements of a thermal system for the space simulator are stated. The second part of the thesis gives a brief overview of the previous solution attempts at the laboratory in Luleå University of Technology, and the manufacturing technologies required to make them. Based on that, a design justification is given. The thermal control system design section gives an overall design description, with detailed report on the iterative design of the sample holders, and thermal simulations results. Additive manufacturing is analyzed, as means of producing solid designs with the necessary performance targets. The overall cost of the designed thermal control system is calculated, and further work directions are proposed. The appendices include the literature used, the technical drawings for manufacturing and assembly of the thermal system, detailed budget calculations, and additional data from the thermal analysis.
9

Product Line Optimization of Force Transducers : Replacing R87 with R03 in Strip Tension Systems

Esmailzadeh Anari, Pedram January 2023 (has links)
The aim of this thesis is to investigate the potential of replacing the material 1.4418 (R87), currently used in ABB's PFCL201 load cells, with the material 1.402 (R03). Both materials possess desirable properties, including high strength, toughness and magnetoelastic characteristics, making them suitable for force transducer applications in strip tension systems. However, the scarcity and high cost of R87 necessitate exploring the feasibility of utilizing the more affordable and easily obtainable R03. The research methodology involved a combination of mechanical and thermal simulations, as well as the evaluation of prototype measurements made from R03. Mechanical simulations were conducted to identify a new load cell geometry that would facilitate the use of R03, while thermal simulations focused on comparing the thermal properties of R03 with real-life measurements. Furthermore, prototypes made from R03 were tested to investigate the transducer characteristics of the material. Lastly, a cost analysis was performed, comparing the manufacturing costs associated with R87 and R03. The study yielded promising results. R03 improves the manufacturing process and significantly reduces the costs related to it. A new load cell geometry was identified, which could be manufactured using existing resources at the factory. Thermal simulations demonstrated improvements in the thermal properties when employing R03. However, measurements of the PFCL201-20 kN load cell made from R03, indicated that to maintain the same accuracy class and commutation angle as the current R87 load cells, the nominal load would need to be adjusted to 12 kN instead of 20 kN. Nonetheless, with the identified geometric modifications, R03 load cells could still be utilized as 20 kN load cells. Alternatively, by changing either the accuracy class or commutation angle. This research provides valuable insights into the possibility of replacing the expensive and scarce R87 material with the more cost-effective and readily available R03 in ABB's PFCL201 load cells. The findings offer a foundation for future studies and potential business decisions regarding material selection and load cell design optimization.
10

Design of high performance buildings : Vulnerability of buildings to climate change from an energy perspective

Gobert, Robin January 2022 (has links)
The challenge of climate change is twofold: to mitigate (prevent) the causes of climate change and to prepare (adapt) to the inevitable effects and consequences. Building and construction are key sectors for decarbonisation (mitigation). The increase in intensity, frequency and duration of heat waves threatens indoor comfort and constitutes a health and comfort risk (adaptation).Therefore, regulations are being changed to take into account related emissions and extreme episodes through new indicators. However, up to now, past climate observations are still used in the calculation of these indicators. This raises the question of how to integrate future climate predictions into regulations. This work aims at characterising the vulnerability of buildings to climate change and aimsat taking into account future climate predictions in building design. It establishes a method for constructing standard weather data based on climate projections and for identifying vulnerable building typologies that are at risk. This project stands out for the use of a large number of building and meteorological data. 77 residential buildings from the Centre Scientifique et Technique du Bâtiment (CSTB) database and 78 years (1981-2058) of weather data for 9 climate models (RCP8.5 scenario) are crossed for Dynamic Thermal Simulations (DTS) on COMETh. The study first highlights the relevance of using reference and extreme years, representative of the climate data, to reduce the number of simulations. The reference year makes it possible to observe the average needs over a period. The extreme year estimates the range of values around this mean.The report then raises the issue of cooling systems as one of the major challenges for energy needs. Under the effect of climate change, heating requirements are decreasing and largely compensate the increase of cooling needs. But few buildings in France are already equipped with cooling systems and the creation of a need exceeding a threshold leads to the purchase of new units. This raises a problem of social equity in access to thermal comfort. Moreover, the environmentalimpact of these systems is more related to refrigerants necessary for the manufacturethan to energy consumption.The research finally proposes a method to classify passive or active buildings (in the sense of cooling needs), that are adapted or not adapted to future extreme weather conditions. This involves applying a clustering algorithm (k-means) to group similar buildings together in terms of energy requirements for different climate models. This method already makes it possible to identify the buildings at risk and to prioritise the measures to be taken (energy renovation). This classification also opens up the possibility of extending this work to newer, larger and more diversified samples. Similar encouraging results were obtained from 2470 offices. They could helpidentify technical and architectural characteristics and assist in the design of efficient passive buildings.

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