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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

Les délices de la flamme : la sensibilité au froid et à la chaleur dans la France moderne (XVIe - XVIIIe siècles) / Delights by the flame : sensitivity to the cold and heat in Modern France (16th-18th centuries)

Jandot, Olivier 07 October 2016 (has links)
À une époque où les conditions matérielles de l’existence différaient profondément de celles qui sont aujourd’hui les nôtres, quel était l’impact des variations saisonnières de températures sur les individus et sur la société ? Comment les hommes et les femmes du passé enduraient-ils le froid de l’hiver et tentaient-ils de s’en préserver ? Quelle était l’efficience des moyens mis en œuvre pour lutter contre le froid et quelles pouvaient être les températures qui régnaient l’hiver à l’intérieur des habitations ? À la suite des intuitions pionnières de Lucien Febvre ou de Robert Mandrou, ce travail, à la croisée de l’histoire du corps et de celle des sensibilités, tente de de retracer la généalogie de notre rapport sensible au monde. La première partie de la thèse, après avoir évoqué les apports et les limites des différents types de sources dépouillées, est consacrée à étudier la manière dont les fluctuations de températures sont perçues, notées et pensées à des époques où le froid et la chaleur sont davantage des expériences sensibles que des grandeurs physiques mesurables. On y étudie aussi la manière dont les vagues de froid impactent, plus qu’aujourd’hui, la vie quotidienne et posent aux individus et à la société d’insolubles difficultés. En s’interrogeant sur la figure récurrente du “grand hiver”, on en vient à montrer que ces descriptions d’hivers rigoureux révèlent tout autant une réalité climatique objective qu’une extrême vulnérabilité des sociétés anciennes face au froid. La seconde partie centrée autour de la question de la civilisation matérielle tente de retracer les différentes stratégies mises en œuvre pour lutter contre les assauts de l’hiver. On y étudie ainsi la place et le rôle de la cheminée dans l’habitation ainsi que la manière dont elle constitue un trait de civilisation qui conditionne des manières d’habiter et des attitudes corporelles qui n’échappent pas au processus de civilisation. Les médiocres performances calorifiques de la cheminée expliquent le recours nécessaire à des sources de chaleur portatives et la mise en place de multiples stratégies de lutte contre le froid qui varient en fonction des régions et des milieux sociaux. La France préindustrielle apparaît ainsi comme un monde de l’économie permanente et de la chaleur rare où le souci constant de l’économie du combustible explique la cohabitation recherchée avec les bêtes, l’entassement des corps dénoncés par les médecins des Lumières et l’existence de certaines formes de sociabilité. En essayant de reconstituer la cohérence d’un système et d’habitus aujourd’hui disparus, on est naturellement amené, dans une troisième partie, à poser la question de la sensibilité — au sens physiologique mais aussi social du terme — au froid et à la chaleur ainsi que celle de son évolution. Dans un essai d’archéologie du corps, on tente de reconstituer les climats intérieurs des habitations d’autrefois en s’efforçant de déterminer les températures de confort. L’accoutumance à des températures intérieures relativement basses au regard de nos exigences actuelles amène à souligner le caractère socialement et culturellement construit des seuils de tolérance et à interroger le rapport à l’inconfort et à la douleur puisque le froid, s’il est enduré, n’en provoque pas moins souffrances et lésions corporelles. En étudiant les cheminements sinueux de la réflexion technique relative à la question du chauffage qui se développe au cours du XVIIIe siècle, on est aussi amené à s’interroger sur les interactions complexes entre la société, les évolutions scientifiques et technologiques et l’évolution des seuils de tolérance individuels et sociaux au froid et à la chaleur. Le XVIIIe siècle apparaît ainsi comme un siècle charnière où s’exprime pour la première fois ouvertement une demande sociale de chaleur (condamnée par les moralistes et les médecins) qui préfigure notre besoin insatiable de confort..... / At the time when material conditions in our existence deeply differed from those we know nowadays, what was the impact of the change in the seasonal temperatures on the individuals and society? How did the men and women of the past endured winter cold and how did they strive to protect themselves from it? How efficient were the means used to fight the cold and what could the indoor temperatures be in winter? After the first intuitions sensed by Lucien Febvre and Robert Mandrou, this work, at the crossroads of the history of the body and that of sensitivity, tries to trace out the genealogy of our sensitive relation to the world. After mentioning the contributions and the limits found in various types of studied sources, the first part of this dissertation is devoted to the way the change in temperatures were perceived, noted or thought at a time when cold and heat were more perceptible experiences than measurable physical quantities. It also deals with the way the cold spells affected daily life and that more than today troubled both the individuals and society with unsolvable difficulties. Wondering about the recurring figure of the “great winter”, it shows that those descriptions of harsh winters revealed a climatic reality as much as the old societies’ extreme vulnerability to the cold. The second part revolving around the question of the material civilization tries to recount the different strategies used to fight the onslaught of winter weather. Thus it studies the role and importance of fire places in homes as well as the way it brought a feature of civilization which changed both the living conditions and the physical attitudes that were implied in the process of civilization. The poor calorific value of fire places explained the necessary resort to mobile heating sources and the establishment of numerous strategies to fight the cold, which changed according to the regions and the social standing. Thus, Preindustrial France was understood as a world of permanent economy and of scarce heat where the constant question of the combustible material economy could explain the importance of living with cattle, of overcrowded places - denounced by the doctors in the Age of Enlightenment - and the existence of certain forms of social skills. Trying to recreate the coherence of a system and habitus that have disappeared today, a third part naturally raises the question of sensitivity – in the physiological but also social meaning of the term – to cold and heat and its evolutions. In an essay on the archeology of the body, we tried to recreate the conditions inside the dwellings of the past, in an effort to determine the comfort temperature. The compliance with relatively low indoor temperatures regarding our current demands led us to underline that our capacity to acceptance had been culturally and socially built up and to question our relation to discomfort and pain since the cold, even though it was supported, entailed suffering and physical damage. Pondering over the technical reflection to the heating issue that had developed throughout the 18th century, we were led to go over the complexity of the interaction between society, scientific and technologic evolution and the individual and social acceptance to the cold and heat. The 18th century seemed to be the turning point where for the first time a social demand for heat had been overtly expressed (though condemned by both moralists and doctors) which heralded our unquenchable need for comfort. The expression for that social demand did not necessarily mean that it would be universally satisfied. Consequently, the old thermal regime would be lasting beyond this studied period…
2

Utvärdering av kommersiell TEG-enhet på en värmeplatta : Generering av elektricitet från temperaturskillnader / Evaluation of commercial TEG on a heatplate

Svensson, Andreas January 2021 (has links)
Att minska energianvändningen är något det pratats mer och mer om de senaste åren. Det finns olika sätt att minska energianvändningen på och ett av dessa är att återvinna värmeenergi. Det kan gälla både spillvärme och nyttig värme. Detta går att tillämpa i industrin, transportsektorn, hushåll och till vardags. Gemensamt för dessa processer är att det används stora mängder energi vilket till stor grad består av förluster till omgivningen eller att processerna inte optimeras. På senare tid har det forskats kring teknologi som kan ta vara på denna värmeenergi och på så vis minska förlusterna. En teknologi för detta är termoelektriska generatorer (TEG) som bygger på Seebeckeffekten för att generera elektricitet från temperaturskillnader. När ett TEG-element utsätts för värme på en sida och kyla på den andra sidan så genereras en elektrisk spänning. En elektrisk ström och effekt kan tas ur kretsen om elementet kopplas till en elektrisk last. Materialet i elementet består av halvledarmaterial med låg värmeledningsförmåga och en hög elektrisk ledningsförmåga. Teknologin har funnits länge men aldrig tillämpats i någon större grad. Nu på senare år har intresset ökat och kommersiella produkter med TEG-element har tagits fram. I detta arbete har en sådan produkt testats för att se hur lämpligt det skulle vara att använda dessa vid hushåll som inte är anslutna till elnätet och har en vedkamin för uppvärmning. TEG-enheten testas på en värmeplatta där ställbara temperaturer är möjliga för att testa prestandan vid temperaturerna 150° C, 200° C och 230° C. En krets sätts ihop för att kunna mäta av värden på spänning och ström vid olika laster som sätts med resistorer. Mätningarna görs med en ökning på 0,1 A vid varje mätning. Resultatet från dessa tester visar att maximal effekt på 14 W uppnås hos produkten vid 230° C. När modifiering av produkten görs för att öka temperaturskillnaden uppnås 17,8 W vilket tyder på att effekten ökar när delta T ökar. Den spänning som uppnås vid öppen krets var som högst 31 V och vid maximal effekt var den 17,8 V. Strömmen var då 1 A. De resultat som testerna gav levde inte upp till de 25 W som produkten sägs kunna ge. Produkten saknar även viktiga komponenter så som spänningsreglerare.Det går av både teori och tester avgöra att det är ett lämpligt sätt att använda sig av TEG-enheter för att generera små mängder elektricitet vid hushåll utan koppling till elnätet. / In recent years the topic of reducing the energy usage has been on the agenda. There are several ways of reducing the energy usage and one of these is to recycle heat energy. It could be both waste heat and useful heat. This can be implied to the industry, transport sector, households and on daily activities. The common factor between these is that large quantities of energy is used and to a large extent consists of losses to the surrounding or from processes that are not optimized. In recent time there has been done research around technology that can recycle and use this heat energy and in return reduce the energy usage. One technology to do this is thermoelectric generators (TEG) that are implementing the Seebeck effect to generate electricity from temperature differences. When a TEG-element have one side that is exposed to a heat source and one side being cooled down an electric voltage is being generated. An electric current and power can then be used from the circuit if the element is connected to an electric load. The material in the element exists of semiconductive materials with low heat conductivity and high electric conductivity. The technology has existed for a long time but has never been implemented to a larger extent. It is only in recent years that the interest has grown and some commercial products with TEG-elements has been developed. In this thesis one of these products has been tested to see how viable it would be to use these within a household that is not connected to the electrical grid and where the house is heated with a wood-burning stove. The TEG-product is tested on a heat plate where it is possible to set a desired temperature. The temperatures of 150° C, 200° C and 230° C are chosen for testing the performance of the product. A circuit is put together to be able to read the values of the voltage and current at different loads that are set with resistors. The measurements are done with an increase of 0,1 A for every measurement. The result from these tests shows that the maximum power of 14 W is achieved at 230° C on the hot side. But when modification of the product is made to increase the temperature difference a value of 17,8 W is attained. This indicate that the power is increasing when the temperature difference is increasing. The attained voltage at open circuit was as highest 31 V and at maximum power it was 17,8 V. The current was then 1 A. The results that the testing gave did not match the value of 25 W that the datasheet says the product can deliver. Also, the product is missing important components such as voltage regulator.It is possible from both the theory and the testing to see that it is suitable to use a TEG-product to generate small amount of electricity to households that are not connected to the electrical grid.

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