With the growing interest in converting a wide variety of biomass-based feedstocks to biofuels, there is a need to develop effective procedures for the design and optimization of multi-feedstock biorefineries. The unifying goal of this work is the development of systematic methodologies and procedures for designing flexible multifeedstock biorefineries. This work addresses four problems that constitute building blocks towards achieving the unifying goal of the dissertation. The first problem addresses the design and techno-economic analysis of an integrated system for the production of biodiesel from algal oil. With the sequestration of carbon dioxide from power plant flue gases, algae growth and processing has the potential to reduce greenhouse gas emissions. Algae are a non-food oil feedstock source and various pathways and technologies for obtaining algal oil were investigated. Detailed economic and sensitivity analysis reveal specific scenarios that lead to profitability of algal oil as an alternative feedstock. In the second problem, a new safety metric is introduced and utilized in process design and selection. A case study was solved to assess the potential of producing biodiesel from sewage sludge. The entire process was evaluated based on multiple criteria including cost, technology and safety. The third problem is concerned with incorporating flexibility in the design phase of the development of multi-feedstock biofuel production processes. A mathematical formulation is developed for determining the optimal flexible design for a biorefinery that is to accommodate the use of multiple feedstocks. Various objective functions may be utilized for the flexible plant depending on the purpose of the flexibility analysis and a case study is presented to demonstrate one such objective function. Finally, the development of a systematic procedure for incorporating flexibility and heat integration in the design phase of a flexible feedstock production process is introduced for the fourth problem. A mathematical formulation is developed for use in determining the heat exchange network design. By incorporating the feedstock scenarios under investigation, a mixed integer linear program is generated and a flexible heat exchange network scheme can be developed. The solution provides for a network that can accommodate the heating and cooling demands of the various scenarios while meeting minimum utility targets.

Failure to maintain thermal equilibrium can cause uncontrollable increases in body core temperature beyond critical upper limits. In selecting clothing, consideration must be given to the heat transfer properties of clothing that may restrict the cooling capacity of the human body under heat stress conditions, most importantly, apparent total evaporative resistance (Re,T,a). This study calculated and compared Re,T,a for five clothing ensembles under varying heat stress conditions, including three relative humidity (RH) levels and three stages of heat stress to determine if Re,T,a values varied or remained the same with changes in heat stress conditions. A four-way mixed model analysis of variance demonstrated significant differences for estimated Re,T,a values among ensembles, RH levels, heat stress stages, and interactions among ensembles and RH levels and ensembles and heat stress stages (p < 0.0001). No significant interaction among RH levels and heat stress stages was found (p = 0.67). A Tukey's Honestly Significant Difference multiple comparison test was used to identify where significant differences occurred (p < 0.05). The results of the study indicated that Re,T,a values do change with RH levels and stages of heat stress and that the theoretical framework for explaining heat-exchange in hot environments is not yet well-established. Also confirmed was the dominance of the convection pathway over the diffusion pathway in hot environments.

The present thesis is focused on calculation prediction of characteristic parameters of combustion process in combustion chamber which is installed at burners testing laboratory. In the thesis basic theoretical knowledge needed for description of heat transfer in process combustion equipment are given. The Plug Flow Furnace Model is based on this knowledge. This model is used to evaluation of specific heat flux in tube furnaces. In the next step the Plug – Flow model is modified and adapted on the combustion chamber. Obtained results are compared with a measured data. By this comparison quality of this model is assessed.

The thesis deals with the design of the boiler to combustion of mixed communal waste. The introductory chapters present introduction of the problem, short explanation about fuel of the boiler and speciality of the boiler to combustion of mixed communal waste. The main part is the heat calculation of the boiler, which consists of stoichiometry of the combustion, heat losses, then disposition of heat performances to individual exchange surfaces. In the end is summary of calculation and knowledge consequent of the calculation.

Impact craters are formed when a large meteorite or comethits the Earth. At the impact a shock wave is released causingabundant fracturing in the surrounding bedrock. This type offracturing is intense and occurs throughout a very large volume(&gt;100 km3) of the bedrock. Fractures of this type have beenobserved in deep drilling, to 5 km depth, in thePuchezh-Katunki Impact Crater. At theses depths the ambienttemperature is high. Thus impact structures are candidates forpotential heat-exchange sources for extraction of geothermalenergy. There is a relation between fracture intensity and electricresistivity in bedrock predominated by impact-generatedfractures. In crystalline bedrock changes in electricresistivity is mainly due to fracturing which is the mainsource of porosity in these rocks. Electric resistivity methodsare highly sensitivity to porosity. Furthermore highfracture-intensities have generally been associated with lowelectric resistivity. Electro-magnetic methods like Very LowFrequency Resistivity (VLF-R) and Magnetotellurics (MT) canindirectly measure electric resistivity to relatively largedepths in the bedrock. This study will quantify the relationship between fractureintensity and electric resistivity which can be used as aprospecting tool for geothermal energy resources at largedepth. To meet that end, a method for fracture mapping on outcropsin Swedish terrain and a method to calculate thethree-dimensional fracture frequency from two-dimensionalfracture data has been developed. The fracture traces measuredin two dimensions on outcrops are assumed to represent avertical surface and must be converted to a three-dimensionalmeasure of the fracture frequency per unit volume. Spacing, dipand trace length of fractures have been accounted for. Thebiases associated with the mapping method have also beenaccounted for (II). The correlation between impact-induced fracturing andelectric resistivity in crystalline rocks in the Lockne Areashows that the extent of impact fracturing in crystalline rockscan be measured with electro-magnetic or electric techniques.In addition the electric resistivity of crystalline basementand impact generated Tandsby Breccia from the Lockne Craterwere determined (I). The relation between fracture frequency and electricresistivity in fresh water conditions using the VLF-R method isestablished from data collected from both two drill holes andfrom numerous outcrops in the Björkö region. Apreliminary quantification of the fracture frequency has beenmade. The MT resistivity models, related to the two drillholes, show that porosity and mineral-conductivity variationsof the bedrock affect this relation more than the salinityvariations in the bore-hole fluid. Further research is neededto establish a firm relation between fracture frequency,salinity of rock fluid, conductivity and porosity in order tovalidate the MT resistivity models (III). Keywords:Electric resistivity, Fracture frequency,Impact generated fractures, Electro-magnetic techniques, VLF-Rmethod, MT method, Window-mapping technique, Three-dimensionalfracture calculations, heat-exchange structure, geothermalenergy.

The focus of this thesis work was the development of an approachto couple a previosly existing Thermal Energy Storage (TES) modelwritten in C++ with a Simulink/Simscape plant model to simulate anAdvanced Adiabatic Compressed Air Energy Storage (AA-CAES) plant.After the creation and validation of such tool, the complete modelwas used to run simulations, with the aim of assessing the AA-CAESplant's performance under multiple patterns of charge anddischarge.Most of the works found in the literature only provide values ofstorage efficiency obtained from analytical approaches, whilethose that use simulation tools provide average values ofefficiencies when the plant is performing a series of identicalcycles of charge and discharge. During this thesis project,instead, simulations were performed for consecutive irregularcycles determined as the plant response to the electric grid powerrequest. The average efficiency values obtained provide thereforea better representation of how the plant would perform in realapplications.The results show that, under the assumptions made, the AA-CAESplant's overall storage efficiency is influenced very weakly byalterations of the charge-discharge patterns, and that goodperformances can be expected not only for identical chargedischargeconsucutive cycles, but for any pattern that observesthe cavern pressure limits, as long as the thermal energy storageis sized wisely.In addition, a sensitivity analysis was performed in order toassess the influence of turbomachinery efficiency on overallstorage efficiency, for a specified plant layout. The results showthat the turbine efficiency is the most affecting parameter to theplant's performance, while the impact of the main compressors'sinefficiency is mitigated by the thermal recovery that takes placein the TES.The present work confirms that AA-CAES is a promising technologyand that storage efficiencies above 70% can be achieved even inrealistic production scenarios.Finally, future steps for more accurate simulations of plants'performances and more detailed energy production scenarios areproposed.MSc ET 18007Examinator: Joakim WidénÄmnesgranskare: Ane HåkanssonHandledare:

Le développement et l’utilisation de nouveaux matériaux, tel que le carbure de silicium (SiC) et le nitrure de gallium (GaN), a permis un accroissement sensible des densités d’énergie traitées par les nouveaux composants de l’électronique de puissance, assortie d’une augmentation de leur compacité. Parallèlement à ces progrès technologiques, la généralisation de l’électricité en tant que vecteur d’énergie primaire au sein de systèmes de plus en plus répartis, incluant des moyens de traitement de l’information au plus près de la fonction réalisée, ouvre la voie à une nouvelle génération de systèmes mécatroniques hautement intégrés. Or, l’émergence de ces nouvelles fonctions soulève une question critique liée au mode de refroidissement de ces éléments. Cette question est intimement couplée aux aspects énergétiques et à leur impact environnemental, imposant une amélioration significative des rendements énergétiques mesurés à l’échelle de la fonction complète. C’est dans ce contexte que l’étude présentée traite tout d’abord de systèmes de récupération de la chaleur résiduelle dissipée au sein de systèmes électroniques de puissance en vue d’alimenter de manière autonome des capteurs, où autres systèmes fonctionnels, via l’énergie « ambiante » ainsi récupérée. Parmi les consommateurs plus particulièrement ciblés, des fonctions innovantes d’intensification par voie électromécanique des échanges de chaleurs au sein d’échangeurs thermique sont étudiées et mises en œuvre. A terme, l’idée serait ainsi d’alimenter les systèmes d’actionnement assurant l’optimisation des échanges de chaleur au sein du système de refroidissement d’une carte électronique au moyen même de la chaleur qu’elle dissipe, récupérée sous forme d’énergie électrique. A cette fin, les différents procédés de conversion de la chaleur en électricité sont examinés, modélisés et mis en œuvre dans la suite de ce travail. Deux types de conversion d’énergie complémentaires sont tour à tour considérés : La conversion par effet thermoélectrique, utilisant l’effet Seebeck qui a lieu en présence d’un gradient de température et l’effet pyroélectrique qui apparait en présence de variation temporelle de la température. Ces deux phénomènes sont analysés et décrits à l’aide de modélisations physiques et comportementales, incluant une approche expérimentale ayant nécessité la mise en place de bancs d’essai spécifiques. L’électricité récupérée par conversion pyroélectrique est par la suite mise en forme grâce à des systèmes de redressement à faible tension de seuil spécialement développés. La faisabilité de systèmes d’alimentation autonomes de capteurs déportés, où de systèmes d’émission (ponctuelle) de mesure, est alors concrètement démontrée en se basant sur les résultats obtenus. Ouvrant la voie à un concept de refroidissement actif des puces électroniques, tirant directement parti de la chaleur dissipée pour son alimentation grâce aux deux procédés préalablement étudiés, la problématique de l’intensification des transferts de chaleur au sein de boucles de refroidissement mécaniquement activées est abordée dans la dernière partie du mémoire. Cette activation est réalisée à l’aide d’un système d’actionnement multicellulaire réparti à base d’actionneurs piézoélectriques. Développée en étroite collaboration avec des équipes de thermodynamiciens, l’idée est de réaliser un pompage de fluide ainsi qu’une modification des échanges de chaleur au sein d’un système de transfert de chaleur en activant les parois de l’échangeur de chaleur par déformation. Le système d’actionnement préconisé est tout d’abord étudié et simulé par un calcul par éléments finis. Un prototype est construit et caractérisé sous conditions réelles dans un deuxième temps. [...] / The development and use of new materials, such as silicon carbide (SiC) and gallium nitride (GaN) has a significant increase in energy densities handled by the new components of power electronics, accompanied by an increase in compactness. Parallel to these technological advances, the widespread use of electricity as a primary energy carrier within systems increasingly distributed, including means for processing information closer to the function carried out, paving the way a new generation of highly integrated mechatronic systems. However, the emergence of these new features raises a critical question related to cooling mode thereof. This question is closely coupled to the energy aspects and their environmental impact, imposing a significant improvement in measured across the full energy function returns. It is in this context that the present study deals firstly recovery systems waste heat dissipated in power electronic systems for autonomous power sensors, where other functional systems via energy "room" and recovered. Particularly among targeted consumers, innovative features intensification electromechanically exchanges heat in heat exchangers are studied and implemented. Eventually, the idea would be to supply the operating systems for the optimization of heat exchange in the cooling system of an electronic card in the same way that heat dissipates, recovered in the form of electrical energy. To this end, various methods of conversion of heat into electricity are considered, modeled and implemented in the course of this work. Two complementary types of energy conversion are considered in turn : The thermoelectric conversion effect by using the Seebeck effect which takes place in the presence of a temperature gradient and the pyroelectric effect that appears in the presence of temporal variation of the temperature. These two phenomena are analyzed and described using physical and behavioral models, including an experimental approach requiring the establishment of specific test benches. The electricity recovered by pyroelectric conversion is then formatted with recovery systems, low voltage specially developed threshold. The feasibility of remote sensors autonomous supply, where emission (point) measuring systems, is then demonstrated concretely based on the results systems. Paving the way to a concept of active cooling computer chips, drawing directly from the heat dissipated for food through two methods previously studied the problem of intensification of heat transfer in cooling loops mechanically activated is discussed in the latter part of the memory. This activation is carried out using a distributed drive system multicellular based piezoelectric actuators. Developed in close collaboration with teams of thermodynamics, the idea is to provide a fluid pump and a change of heat transfer in a heat transfer system by activating the walls of the heat exchanger deformation. The operating system is called first studied and simulated by a finite element calculation. A prototype is built and characterized under actual conditions in a second time. The multicellular actuating system composed of a plurality of actuators and a supply system configurable multipath is then integrated into an exchange of heat testbed specifically developed. This experience is a fundamental first step in the development of electroactive systems, potentially autonomous, allowing the intensification of heat exchange in cooling loops for high-performance power electronics.

[pt] A pasta de gelo é uma mistura de água e um aditivo, com finas partículas de gelo, apresentando uma alta densidade de energia térmica. O principal motivo de sua utilização deve-se à combinação do aproveitamento do calor latente na mudança de fase com capacidade de ser bombeado. O presente trabalho trata do estudo experimental sobre a transfe rência de calor e queda de pressão, com mudança de fase, utilizando uma mistura de propileno glicol - água com 13,8% de concentração em peso, num trocador de calor de placas com arranjo em U para 16 placas. Realizaram-se testes de troca de calor com escoamento em paralelo e contra-corrente, para duas condições de fração mássica de gelo e números de Reynolds para a pasta de gelo entre 150 e 425, com diferentes condições de carga térmica. Dos testes foram observados aumentos de até 25% no coeficiente global de troca calor, ao se incrementar a vazão e, conseqüentemente, o número de Reynolds da pasta de gelo. Com o aumento da fração de gelo melhora-se a capacidade de resfriamento, diminuindo o número de Nusselt da pasta de gelo. O coeficiente global de troca, porém, começa a diminuir. Na literatura esta relação ainda não está bem definida. Alguns autores relatam ganhos, perdas ou indiferença no coeficiente global. Resultados do coeficiente global e do número de Nusselt, nos modos paralelo e contra-corrente, não apresentaram grande diferença. A capacidade de resfriamento em contra-corrente foi maior, apresentando valores de efetividade cerca 10% acima dos resultados observados no modo paralelo. Os fatores de atrito encontrados variaram entre 0,030 a 0,085, o que concorda com os resultados apresentados por outros pesquisadores. Como era de se esperar, o fator de atrito diminui com o aumento da vazão mássica e de maneira inversa com o aumento da fração de gelo. / [en] Ice slurry is an aqueous solution from which ice crystals are formed. These crystals possess high energy density, in the form of latent heat. Furthermore, the fact of being a slurry makes it an excellent energy carrier, for it can be easily pumped. The present work presents an experimental procedure to assess the heat transfer and the pressure loss, with phase change, using a mixture of propyleneglycol and water, 13.8% weight, in a U-plate heat exchanger with 16 plates. Tests were carried out for both parallel and counter-flow configurations of the heat exchanger, for two different mass fractions of ice and with Reynolds numbers between 150 and 425 for the slurry. Different thermal loads were considered. The experiments showed increases of up to 25% in the overall heat transfer coeficiente when the slurry flow is increased, with consequent increase in the Reynolds number. By increasing the ice fraction the cooling capacity is improved, reducing the Nusselt number. In the literature, this relationship is not clearly defined, as some authors show gains in the heat exchange coefficient, losses, and some others did not observe any influence on this parameter. Regarding the heat Exchange configuration, i.e., parallel or counter-flow, neither the heat exchange coefficient, nor the Nusselt number suffered major influence. The effectiveness is up to 10% higher for the counter-flow configuration in comparison with the parallel configuration. The figures found for the friction coefficient, between 0,030 and 0,085, are in good agreement with the literature. As expected, the friction coefficient decreases when the mass flow is increased, and increases when the ice fraction is increased.

Ce travail de thèse vise à comprendre et analyser les échanges thermiques qui ont lieu entre un bâtiment et son environnement en présence de parois végétalisées « intensives ». Nous présentons dans ce manuscrit, une démarche numérique et expérimentale sur l’évaluation de l’incidence thermique de ces Murs Végétalisés (MV). Une plateforme constituée de trois prototypes identiques (3 mini-laboratoires thermiques) sous conditions climatiques réelles a été conçue et instrumentée. Dans un premier temps, deux écrans permettant une variation rapide et graduelle des taux de couvertures de 10 à 100% ont été ajoutés devant les prototypes. Ainsi, plusieurs séries de mesures ont été effectuées et des réductions significatives au niveau des températures et des flux de chaleur ont été enregistrées et interprétées. Cette démarche expérimentale avait pour premier objectif de mettre en oeuvre une occultation artificielle et donc maîtrisée. Un premier modèle a été développé sur la base de l’écriture des équations de bilan des échanges thermiques entre la paroi à occultation variable et son environnement climatique. Ce modèle confronté aux résultats fournis par l’expérimentation apermis de valider les approches théoriques au niveau des transferts radiatifs et convectifs. Dans un deuxième temps, le premier modèle qui a été développé dans ce travail a été adapté au cas d’une occultation « réelle » par de la végétation (lierre ou vigne vierge) puis validé expérimentalement. Il a été finalement implémenté dans un code de simulation thermique dynamique de bâtiment (TRNSYS), et ainsi l’incidence thermique des murs végétalisés simples (intensifs) a pu être évaluée à l’échelle réelle d’un bâtiment. Les résultats de simulations pour un climat tempéré montrent que la présence des plantes à feuilles persistantes a un impact négatif sur la demande énergétique hivernale. A l’inverse, en période estivale, les résultats montrent que les murs végétalisés ont un intérêt au niveau de la limitation des surchauffes. Leur présence réduit alors notablement la consommation énergétique nécessaire pour « climatiser » le bâtiment et améliore ainsi le confort thermique intérieur. / This PhD thesis aims to understand and analyse the heat exchanges that occur between a building and its environment in the presence of intensive vegetated walls. In this manuscript, a numerical and experimental approach to evaluate the thermal impact of green walls is presented. A platform composed of three identical prototypes (3 thermal mini-laboratories) under real weather conditions has been designed and instrumented. As a first step, two screens permitting a rapid and gradual variation of coverage rate from 10 to 100% were added to the prototypes. Thus, several series of measurements were performed and significant reductions in temperature and heat flow were recorded and interpreted. The primary objective of this experimental approach was to implement an artificial shading and thus controlled. A first model was developed based on the writing of heat exchanges energy balance equations between the wall with variable coverage rate and its climatic environment. This model confronted to the experimental results allowed the validation of the theoreticalapproaches at the level of radiative and convective heat transfer. Secondly, the first model that was developed in this work has been adapted to the case of a "real" occultation by vegetation (Ivy or Virginia creeper) then validated experimentally.It was finally implemented in a dynamic thermal simulation code (TRNSYS), and thus the thermal impact of green walls were evaluated at the real scale of a building. Simulation results in a temperate climate show that the presence of evergreen plants has a negative impact on winter energy demand. Conversely, in summer, the results show that green walls have an interest in limiting overheating. Their presence significantly reduces energy consumption needed to cool the building and improves the indoor thermal comfort.

Diplomová práce se zabývá membránovou destilací, především z matematické perspektivy. Jedná se o tepelně poháněný separační proces, ve kterém se pro rozdělení kapalné a plynné fáze používá porézní membrána. Kapalina se vypařuje a její plynná fáze prochází přes póry v membráně. Během tohoto procesu dochází k tepelné i látkové výměně, které jsou popsány systémem parciálních diferenciálnich rovnic. Další model je založen na analogii s elektrickými obvody, zákonu zachování energie, hmotnostní bilanci a empirických vztazích. Je ověřen s experimentálně naměřenými daty z nové alternativní destilační jednotky používající membránu a kondenzátor z polymerních dutých vláken. Výkon a účinnost jednotky jsou vyhodnoceny. Další možná vylepšení jsou navržena.