Žmogaus organizmas yra linkęs aklimuotis ir prie besikartojančių šilumos ir prie besikartojančių šalčio stimulų (Michael, 2001). Tai sukelia skirtingus fiziologinius atsakus organizme. Žmogaus organizmas aklimuodamasis šilumai siekia sušvelninti šilumos sukeltą fiziologinį stresą, ir pagerinti šiluminį komfortą bei treniravimosi galimybes. Aklimacija yra sukeliama pakartotinių šilumos stimulų, kurie sukelia pakankamą stresą, galintį pakelti odos ir vidines temperatūras, padidinti prakaitavimą. Dažniausiai aklimacija kasdien pasikartojantiems šilumos stimulams atsiranda per pirmas 4 dienas ir galutinai susiformuoja per 3 savaites. Šilumos aklimacijos sukelti požymiai – žemesnė vidinė temperatūra, padidėjęs prakaitavimas ir odos kraujotaka, sumažėjusi metabolinė medžiagų apykaita, sumažėjęs širdies ir kraujagyslių sistemai sukeliamas krūvis, pagerėjęs skysčių balansas ir padidėjusi šiluminė tolerancija (Michael ir kt., 2001). Šiais laikais profesinė ir rekreacinė veikla šaltomis oro sąlygomis yra gana dažna. Šalčio poveikis sukelia termoreguliacijos atsakus, kurie pasireiškia elgesiu arba fiziologiniais pokyčiais, kad išlaikytų šiluminę pusiausvyrą- padidėjusia metabolinė šilumos gamyba drebant arba vazokonstrikcija- sumažėjusiu šilumos atidavimu. Šie fiziologiniai atsakai priklauso nuo asmens individualių savybių- amžiaus, kūno sudėjimo, bendro prisitaikymo šalčiui. Stiprus šalčio stimulas gali sukelti medicinines traumas ar net mirtį (Launay, 2009). Aklimacija šalčiui yra... [toliau žr. visą tekstą] / Human body tends to acclimate to repeated heat or cold stimulus (Michael, 2001). This leads to different physiological responses in the body. During acclimation to heat the body seeks to soften heat-induced physiological stress, to improve thermal comfort and increase training opportunities. Acclimation is induced by repeated heat stimuli that cause sufficient stress, that can raise skin and core temperature, increase sweating. Usually the acclimation to daily repeated heat stimuli occurs within the first 4 days and finally forms during 3 weeks. Heat acclimation causes symptoms such as lower core temperature, increased sweating and skin blood circulation, decreased metabolism, decreased stress for cardiovascular system, improved fluid balance and increased thermal tolerance (Michael et al., 2001). Nowadays, professional and recreational activities in cold weather conditions are quite common. Cold exposures cause thermoregulatory responses that affects behaviour or physiological changes to maintain thermal balance- increased metabolic heat production while shivering, or vasoconstriction- reduced heating. These physiological responses depend on the person’s individual characteristics- age, body composition and general adaptation to cold. A strong cold stimulus can cause medical injuries or even death (Launey, 2009). Acclimation to cold is classified into several categories- metabolic, insulation, hypothermic and intermediate versions (Bittel, 1992). Acclimation to cold may... [to full text]

Made available in DSpace on 2016-06-02T20:09:08Z (GMT). No. of bitstreams: 1 1646.pdf: 3878244 bytes, checksum: 1b913364f7458c2e95fc16bda01f835e (MD5) Previous issue date: 2007-08-01 / Financiadora de Estudos e Projetos / This research focuses the evaporative cooling by water aspersion on wavy cement fiber tiles in the city of São Carlos, SP, seeking to use it to reduce the buildings heat gains. A theoretical model was developed, based on classic equations of fluids mechanic, applied to iterative calculations of heat flows on the tile superior surface, considered as control surface. In the work development, this model was progressively adjusted to experimental data obtained in a test cell, exposed to the local climatic conditions, with the monitoring of superficial temperatures of both faces in two tiles, one maintained dry and other under intermittent aspersion of water. The research results indicated that, despite of still being susceptible to improvement, the theoretical model already presents quite satisfactory approach with the measured data. Applying a statistical adjustment to the proposed model of iterative heat flows calculation, it was obtained a correlation coefficient between measured and estimated temperatures of 0,999 and a standard deviation of 0,35 ºC. During the experiments, the average evaporative heat flow was 409 W/m2. Theaverage water volume evaporated was 0,7 l/(m².h), corresponding to an average difference of temperatures among the compared tiles of 5,12 K, for the daylight period. Due to the growing need of energy consumption reduction, this procedure seems to be a good option to reduce buildings thermal load, if compared to conventional air conditioning systems / Esta pesquisa enfoca a refrigeração evaporativa por aspersão de água sobre telhas onduladas de fibrocimento, na cidade de São Carlos, SP, visando sua utilização para redução dos ganhos de calor em edificações. Um modelo teórico foi desenvolvido, baseado em equações clássicas da mecânica dos fluidos, aplicadas em cálculos iterativos dos fluxos de calor sobre a superfície superior da telha, considerada como superfície de controle. No desenvolvimento do trabalho, este modelo foi progressivamente ajustado a dados experimentais obtidos em uma célula de teste, exposta às condições climáticas locais, sendo monitoradas temperaturas superficiais de ambas as faces em duas telhas, uma mantida seca e outra sob aspersão intermitente de água. Os resultados da pesquisa indicaram que, apesar de ainda ser passível de aprimoramento, o modelo teórico já apresenta aproximação bastante satisfatória com os dados medidos. Aplicando-se um ajuste estatístico ao modelo proposto de cálculo iterativo dos fluxos de calor, obteve-se um coeficiente de correlação entre temperaturas medidas e estimadas de 0,999 e um desvio padrão de 0,35 ºC. Durante os experimentos, o fluxo médio de calor por evaporação foi de 409 W/m2. O volume médio de água evaporado foi de 0,7 l/(m².h), correspondendo a uma diferença média de temperaturas entre as telhas comparadas, para o período diurno, de 5,12 K. Frente à crescente necessidade de redução de consumo de energia, esta parece uma boa opção para redução da carga térmica dos edifícios, se comparada aos sistemas convencionais de condicionamento de ar

La conception des bâtiments à faible consommation d'énergie est devenue un enjeu très important à travers le monde afin de minimiser la consommation d'énergie et les émissions de gaz à effet de serre associés. Au Maroc, le secteur du bâtiment représente 25% de la consommation énergétique finale du pays avec 18% réservée au résidentiel et 7% pour le tertiaire (ADEREE 2011). L'intégration de systèmes passifs ou semi-passifs de rafraîchissement/chauffage dans le bâtiment est désormais indispensable pour la réduction de la consommation énergétique tout en améliorant le confort thermique. Un de ces systèmes est l’échangeur air-sol (EAHX). Le principe du rafraîchissement à l'aide de l’échangeur air-sol est bien établi, mais le comportement d'un tel système dépend des conditions climatiques et de la nature du sol. L’échangeur air-sol étudié est installé dans une maison type villa située dans la banlieue de Marrakech. Un monitoring de ce système a été réalisé durant l’été 2013 à travers un suivi des températures et de l'humidité durant 39 jours. Les résultats montrent que l’échangeur air-sol est un système adapté pour le rafraîchissement de l’air dans les bâtiments à Marrakech, puisqu’il procure une température de soufflage quasi-constante d’environ 22°C pour le débit 244 m3/h et 25°C pour le débit de 312m3/h, avec une humidité relative autour de 50 % alors que la température extérieure dépasse 40°C. Le modèle mathématique choisi et l’outil de simulation associé, Type 460 opérant sous le logiciel commercial TRNSYS, sont analysés et validés par confrontation avec les résultats expérimentaux. Cette confrontation a montré une excellente concordance, avec un écart absolu moyen entre la mesure et la simulation toujours inférieur à 0,5°C et décroit à 0,2°C à la sortie de tube enterré. La validation de l’outil de simulation avec un échangeur air-sol enterré dans un sol soumis à conditions météorologiques extérieures n’a pas été réalisée auparavant. D'autre part, les simulations dynamiques de l’échangeur air-sol sont réalisées en fonctionnement continu, avec 1 et 3 tubes durant la période chaude de l’année (mai-septembre). Les résultats montrent que le système procure une température à la sortie de tube enterré de 25,1°C (1 tube) et 26 °C (3 tubes). Il en résulte une capacité de refroidissement de 58w/m2 (1 tube) et 55w/m2 (3 tubes) pour une température à l’entrée de 44,6°C. Une étude de sensibilité, utilisant la méthode de Sobol, de la performance thermique de l'échangeur durant la saison chaude (mai-septembre) a permis de dégager les paramètres les plus influents. Par la suite, une étude paramétrique complète sur l’énergie sensible totale perdue par l’air lors dans son passage dans l’échangeur air-sol est réalisée en fonction des paramètres les plus influents déterminés auparavant. / The low energy buildings tendency has become a major worldwide key to minimize energy consumption and greenhouse gas emissions issues. In Morocco, the building sector represents 25% of the total final energy consumption, whereas 18% is dedicated for residential and 7% for the tertiary sector (ADEREE 2011). The integration of passive or semi-passive for cooling/heating purposes into buildings is an essential act for reducing energy consumption while improving thermal comfort. One of these systems is the Earth to Air Heat Exchanger (EAHX). Its principle to use the ground-coupled heat exchanger for cooling is well established, but the behavior of such a system depends on the climate and the soil, which influences the choice of design parameters of this system. We performed a numerical and experimental study on the thermal performance of an Earth to air heat exchanger installed in a villa type house in the suburbs of Marrakech. A monitoring survey was conducted during the summer period of 2013, to acquire temperature and humidity measurements for 39 days. The results show that the earth to air heat exchanger is a system more adapted to refresh the air in buildings in Marrakech, as it provides a quasi constant air temperature of approximately 22°C for flow 244 m3/h and 25°C for flow of 312 m3/h, with relative humidity that is around 50% when the outside temperature exceeds 40°C. The mathematical model chosen and the associated simulation tool used is Type 460 operating under the TRNSYS commercial software, analyzed and validated by comparison with experimental results. This comparison showed excellent agreement, with an average absolute difference between the measurement and simulation that is always lower than 0.5°C and 0.2°C as it decreases at the output of the buried pipe. On the other hand, dynamic simulations of the EAHX using TRNSYS software (TYPE 460) were performed with one pipe or three pipes continuously running. The achieving specific cooling capacity is 58 W/m2 (one pipe) and 55 W/m2 (three pipes) obtained for air temperatures of 25 °C and 26 °C respectively, at the EAHX outlet and 44.6 °C at its inlet. A sensitivity analysis, using the method of Sobol, of the thermal performance of the earth air heat exchanger (EAHX) in the hot season (May-September) has identified the most influential parameters. Thereafter, a complete parametric study on the total sensible energy lost through the air when in passing through the air-ground heat exchanger is made based on the most influential parameters determined previously.

Ce mémoire présente une étude sur le refroidissement passif de batteries lithium-ion. Il se compose de deux grandes parties. La première partie est une étude expérimentale et numérique du comportement thermique d’une batterie et la seconde partie est l’étude expérimentale d’un système passif pour le refroidissement de plusieurs batteries. Un banc d’essais expérimental a été conçu pour suivre l’évolution thermique des batteries soumises à différents courants de sollicitation. Les batteries prismatiques étudiées sont de type LFP et de capacité 60 Ah. Dans un premier temps, le comportement thermique d’une batterie soumise à des cycles de charge / décharge, est caractérisé expérimentalement. Nous montrons que la température n’est pas uniforme à la surface de la batterie et la zone la plus chaude est identifiée. Dans un second temps, un modèle numérique tridimensionnel a été développé pour prédire la température en tout point de la batterie. Ce modèle thermique permet de prédire notamment les températures à l’intérieur de la batterie, non mesurées expérimentalement et ceci, pour différents courants de sollicitation. Les données d’entrée du modèle sont issues des essais expérimentaux et de la littérature. Cette phase de caractérisation thermique de la batterie est essentielle pour la conception d’un système de refroidissement. Enfin, une étude expérimentale d’un système de refroidissement passif basé sur des caloducs et des plaques à ailettes est réalisée. Plusieurs configurations sont testées au fur et à mesure en apportant des améliorations aboutissant enfin à un système à dix caloducs munis de plaques à ailettes verticales au niveau du condenseur combinés à des plaques à ailettes placées sur les faces des batteries. / This thesis deals with the passive cooling of lithium-ion batteries. It consists of two large parts. The first part is an experimental and numerical study of the thermal behaviour of a battery and the second part is the experimental study of a passive system for the cooling of several batteries. An experimental test bench was designed to monitor the thermal evolution of batteries subjected to different currents. The prismatic batteries studied are made of lithium-iron-phosphate and have a capacity of 60 Ah. In a first step, the thermal behaviour of a battery subjected to charge / discharge cycles is experimentally characterized. We show that the temperature is not uniform at the surface of the battery and the hottest area is identified. In a second step, a three-dimensional numerical model was developed to predict the temperature at any point of the battery. This thermal model makes it possible to predict in particular the temperatures inside the battery, not measured experimentally and this, for different currents. The model input data are from experimental trials and literature. This phase of thermal characterization of the battery is essential for the design of a cooling system. Finally, an experimental study of a passive cooling system based on heat pipes and finned plates is carried out. Several configurations are tested progressively with improvements leading finally to a system with ten heat pipes with vertical finned plates at the condenser combined with finned plates placed on the faces of the batteries.

The work is focused on issue of passive cooling in a cabin of a car. The basic principles and mechanisms of heat transfer are described in the theoretical part and the quality of cabin environment in terms of thermal comfort and air quality is discussed as well. Next part of the work describing the principles of ventilation and air conditioning of cabins and possible methods of passive cooling are discussed. Passive cooling means decrease of temperature of cars interior, without need of energy supply from car battery, or fuel. The last part of the work includes numerical simulation of selected methods of passive cooling using the THESEUS-FE 3.0 software. Simulations were performed on model of Volkswagen Polo car and primarily were focused on testing of functionality of various methods of passive cooling.

The PhD thesis deals with the theoretical evaluation of the potential use of night cooling techniques in condition of the Czech Republic. Mainly aims to evaluate the potential of night cooling, which uses the physical phenomenon of radiation against the night sky. This technique is widely used mainly in the dry and hot regions where there are the most suitable climatic conditions for this cooling method. The work is based on the current state of knowledge in the area of passive and low-energy cooling systems. These knowledges are applied to the conditions of Czech Republic and by using simulations of the energy, behaviour of the buildings explores the benefits in terms of improving of the internal microclimate and from the perspective of economy operation of conventional cooling equipment. In order to establish the benefits of night cooling on the operation of the building in the dynamically changing conditions, the modular simulation program TRNSYS was used, which is suitable for the analysis of energy systems of buildings and their behaviour. The results of simulation results were converted to thermal comfort parameters of the PMV and the PPD.

Climate change will affect many human activities and sectors. Among those, the built environment will face several challenges with respect to the varying climate conditions. The present study investigated the global warming impacts on energy demand and indoor climate comfort for an office building in Stockholm. Considering a service life of 50 years, the future climate conditions were investigated for the only air temperature increase in 2070, in accordance with the medium forecasted greenhouse gas emissions scenario provided by the International Panel on Climate Change (IPCC). Another climate morphing approach was adopted to develop the climate file for the year 2080 considering the variation of all the weather parameters. Three different passive cooling solutions, such as external roller shade, electrochromic glazing, and internally ventilated shading, have been implemented in the case study building to decrease the cooling demand. The characteristics of the strategies were preliminarily assessed and then implemented into the building energy simulation software IDA-ICE to evaluate the energy performances with respect to the different climates. The results indicated that an increment of the cooling demand and a reduction of the heating usage will be experienced in the future. The different morphing approaches displayed the inherent uncertainties when future evaluations are performed, although similar weather patterns were found. The improvement of the solar and optical properties, such as the introduction of the exhaust air extraction and the electrochromic technology, implied a lower cooling and ventilation usage. The EC technology reported the lowest cooling demand, while the internally ventilated shading option outperformed the others in terms of annual energy consumption. / Klimatförändringar kommer att påverka många mänskliga aktiviteter och sektorer. Bland dem kommer den byggda miljön att möta flera utmaningar med avseende på de olika klimatförhållandena. Denna studie undersökte effekterna av den globala uppvärmningen på energibehovet och inomhusklimatkomforten för en kontorsbyggnad i Stockholm. Med hänsyn till en livslängd på 50 år undersöktes de framtida klimatförhållandena för ökningen av lufttemperaturen utomhus till 2070, i enlighet med det medelprognoserade växthusgasutsläppsscenariot som tillhandahålls av International Panel on Climate Change (IPCC). En annan klimatförändringsmetod antogs för att utveckla klimatfilen för år 2080 med tanke på variationen i alla väderparametrar. Tre olika passiva kyllösningar, såsom utvändigt solskydd (vertikalmarkis med screenväv), elektrokromt glas och invändigt ventilerat solskydd, har implementerats i fallstudiebyggnaden för att minska kylbehovet. Karaktären av strategierna utvärderades preliminärt och implementerades sedan i programvaran för byggenergisimulering IDA-ICE för att utvärdera energiprestanda med avseende på de olika klimaten. Resultaten indikerade att en ökning av kylbehovet och en minskning av värmeanvändningen kommer att ske i framtiden. De olika klimatförändringsmetoderna visade de inneboende/medföljande osäkerheterna när framtida utvärderingar utförs, även om liknande vädermönster hittades. De passiva kyllösningarnas reducering av total solenergitransmission, såsom införandet av frånluftsutsug och den elektrokroma tekniken, innebar en lägre kyl- och ventilationsanvändning. EC-tekniken rapporterade det lägsta kylbehovet, medan det invändiga ventilerade solskyddet överträffade de andra när det gäller årlig energiförbrukning.

Le bâtiment est l'un des secteurs les plus consommateurs d'énergie et producteurs de CO2 au monde. Au Maroc, ce secteur représente actuellement 33% de la consommation totale d’énergie à l'échelle nationale. Le nouveau règlement thermique au Maroc vise à introduire des pratiques éco énergétiques dans ce secteur pour réduire ces consommations. En effet, dans la région méditerranéenne, l’architecture du bâtiment a un impact primordial sur sa performance énergétique et thermique. Par ailleurs, l’intégration des techniques passives et l’utilisation des matériaux locaux pourraient réduire considérablement la consommation d’énergie dans le secteur du bâtiment. C’est dans ce contexte que se situe cette thèse de doctorat dont l’objectif est d’évaluer la capacité de rafraîchissement de quelques techniques passives pour la protection solaire des toitures et de montrer l’importance de l’utilisation des matériaux naturels locaux dans le climat chaud et semi-aride de Marrakech. En effet, trois techniques passives de rafraîchissement de l'air dans les bâtiments sont testées dans des conditions climatiques réelles dans la ville de Marrakech. Les techniques passives, à savoir la peinture blanche, l'ombrage et l'isolation thermique, sont appliquées sur les toits de trois cellules test métalliques placées à l’extérieur. Les performances thermiques de ces techniques sont évaluées simultanément via un monitoring de 29 jours d’été de quatre cellules test identiques, dont une cellule test de référence à toit nu (sans traitement). Ces cellules test ne représentent pas des bâtiments réels là où nous pouvons mener une étude approfondie. Pour cela, nous avons construit un bâtiment réel qui représente une salle de classe dans le milieu rural du Sud marocain, et ceci en utilisant des matériaux naturels et en intégrant des techniques passives dans la toiture. Les performances thermiques et énergétiques des mêmes techniques sont évaluées par le biais des simulations thermiques dynamiques sur l’outil TRNSYS ainsi qu’une étude expérimentale. / The building is one of the most energy-consuming and CO2-producing sectors in the world. Nowadays, this sector accounts for 33% of total energy consumption in Morocco. The new thermal regulation in Morocco aims to introduce eco-energy practices in this sector to reduce this consumption. Indeed, in the Mediterranean region, building architecture has a major impact on its energy and thermal performance. In addition, the integration of passive techniques and the use of local materials could significantly reduce energy consumption in the building sector. In this context where this thesis is located and whose objective is to evaluate the cooling capacity of some passive techniques for the solar protection of roofs and to show the importance of the use of local natural materials in the hot and semi-arid climate of Marrakech. Indeed, three passive cooling techniques are tested in real conditions in the Marrakech region. Passive techniques, namely white paint, shading and thermal insulation, are applied to the roofs of three outside test cells. The thermal performances of these techniques are evaluated simultaneously via a 29-day summer monitoring of four identical test cells, including a bare roof reference test cell (without treatment). Small scale test cells do not represent real buildings where an in-depth study can be conducted. To remedy this, we built a single-zone building that represents a classroom in rural region in southern Morocco, using natural materials and incorporating passive techniques into the roof. The thermal and energetic performances of the same techniques are evaluated by means of dynamic thermal simulations on TRNSYS as well as an experimental study.

abstract: Passive cooling techniques, specifically passive downdraft cooling (PDC), have proven to be a solution that can address issues associated with air conditioning (AC). Globally, over 100 buildings have integrated PDC in its different forms, most of which use direct evaporative cooling. Even though all surveyed buildings were energy efficient and cost-effective and most surveyed buildings were thermally comfortable, application of PDC remains limited. This study aims to advance performance of the single stage passive downdraft evaporative cooling tower (PDECT), and expand its applicability beyond the hot dry conditions where it is typically used, by designing and testing a multi-stage passive and hybrid downdraft cooling tower (PHDCT). Experimental evaluation on half-scale prototypes of these towers was conducted in Tempe, Arizona, during the hot dry and hot humid days of Summer, 2017. Ambient air dry-bulb temperatures ranged between 73.0°F with 82.9 percent coincident relative humidity, and 123.4°F with 7.8 percent coincident relative humidity. Cooling systems in both towers were operated simultaneously to evaluate performance under identical conditions. Results indicated that the hybrid tower outperformed the single stage tower under all ambient conditions and that towers site water consumption was at least 2 times lower than source water required by electric powered AC. Under hot dry conditions, the single stage tower produced average temperature drops of 35°F (5°F higher than what was reported in the literature), average air velocities of 200 fpm, and average cooling capacities of 4 tons. Furthermore, the hybrid tower produced average temperature drops of 45°F (50°F in certain operation modes), average air velocities of 160 fpm, and average cooling capacities exceeding 4 tons. Under hot humid conditions, temperature drops from the single stage tower were limited to the ambient air wet-bulb temperatures whereas drops continued beyond the wet-bulb in the hybrid tower, resulting in 60 percent decline in the former’s cooling capacity while maintaining the capacity of the latter. The outcomes from this study will act as an incentive for designers to consider incorporating PDC into their designs as a viable replacement/supplement to AC; thus, reducing the impact of the built environment on the natural environment. / Dissertation/Thesis / Doctoral Dissertation Architecture 2017

The content of the diploma thesis is evaluation of the usability of carbon composites in the space industry. The aim of this work is to assess whether carbon composites can find application in mechanical systems of passive thermal protection of artificial objects. Model examples demonstrate the principle of operation of selected passive thermal protection. The evaluation is realized based on the results of thermal analysis. Analytical formulas from field theory of heat transfer are used as a calculation method. The diploma thesis consists from two parts. The theoretical part briefly describes the mechanisms of heat transfer, selected types of passive thermal protection and properties and applications of carbon composites. The practical part consists of the assignment, calculation and evaluation of three examples. The results show that carbon composites can compete with commonly used materials for specific requirements.