This research focuses on developing strategies for the optimal control of large-scale Combined Cooling, Heating and Power (CCHP) systems to meet electricity, heating, and cooling demands, and evaluating the cost savings potential associated with it. Optimal control of CCHP systems involves the determination of the mode of operation and set points to satisfy the specific energy requirements for each time period. It is very complex to effectively design optimal control strategies because of the stochastic behavior of energy loads and fuel prices, varying component designs and operational limitations, startup and shutdown events and many more. Also, for large-scale systems, the problem involves a large number of decision variables, both discrete and continuous, and numerous constraints along with the nonlinear performance characteristic curves of equipment. In general, the CCHP energy dispatch problem is intrinsically difficult to solve because of the non-convex, non-differentiable, multimodal and discontinuous nature of the optimization problem along with strong coupling to multiple energy components. <div><br></div><div>This work presents a solution methodology for optimizing the operation of a campus CCHP system using a detailed network energy flow model solved by a hybrid approach combining mixed-integer linear programming (MILP) and nonlinear programming (NLP) optimization techniques. In the first step, MILP optimization is applied to a plant model that includes linear models for all components and a penalty for turning on or off the boilers and steam chillers. The MILP step determines which components need to be turned on and their respective load needed to meet the campus energy demand for the chosen time period (short, medium or long term) with one-hour resolution. Based on the solution from MILP solver as a starting point, the NLP optimization determines the actual hourly state of operation of selected components based on their nonlinear performance characteristics. The optimal energy dispatch algorithm provides operational signals associated with resource allocation ensuring that the systems meet campus electricity, heating, and cooling demands. The chief benefits of this formulation are its ability to determine the optimal mix of equipment with on/off capabilities and penalties for startup and shutdown, consideration of cost from all auxiliary equipment and its applicability to large-scale energy systems with multiple heating, cooling and power generation units resulting in improved performance. </div><div><br></div><div>The case-study considered in this research work is the Wade Power Plant and the Northwest Chiller Plant (NWCP) located at the main campus of Purdue University in West Lafayette, Indiana, USA. The electricity, steam, and chilled water are produced through a CCHP system to meet the campus electricity, heating and cooling demands. The hybrid approach is validated with the plant measurements and then used with the assumption of perfect load forecasts to evaluate the economic benefits of optimal control subjected to different operational conditions and fuel prices. Example cost optimizations were performed for a 24-hour period with known cooling, heating, and electricity demand of Purdue’s main campus, and based on actual real-time prices (RTP) for purchasing electricity from utility. Three optimization cases were considered for analysis: MILP [no on/off switch penalty (SP)]; MILP [including on/off switch penalty (SP)] and NLP optimization. Around 3.5% cost savings is achievable with both MILP optimization cases while almost 10.7% cost savings is achieved using the hybrid MILP-NLP approach compared to the current plant operation. For the selected components from MILP optimization, NLP balances the equipment performance to operate at the state point where its efficiency is maximum while still meeting the demand. Using this hybrid approach, a high-quality global solution is determined when the linear model is feasible while still taking into account the nonlinear nature of the problem. </div><div><br></div><div>Simulations were extended for different seasons to examine the sensitivity of the optimization results to differences in electric, heating and cooling demand. All the optimization results suggest there are opportunities for potential cost savings across all seasons compared to the current operation of the power plant. For a large CCHP plant, this could mean significant savings for a year. The impact of choosing different time range is studied for MILP optimization because any changes in MILP outputs impact the solutions of NLP optimization. Sensitivity analysis of the optimized results to the cost of purchased electricity and natural gas were performed to illustrate the operational switch between steam and electric driven components, generation and purchasing of electricity, and usage of coal and natural gas boilers that occurs for optimal operation. Finally, a modular, generalizable, easy-to-configure optimization framework for the cost-optimal control of large-scale combined cooling, heating and power systems is developed and evaluated.</div>

Detta arbete har undersökt möjligheten att via styrsystemet för en avloppspump-station optimera energiförbrukningen av pumpar och med styrfunktioner förenkla driftunderhållet av stationen.För att undersöka energiförbrukningen har en teoretisk modell av en pumpstation gjorts där energitester för tre olika reglermetoder simulerats. Två av metoderna var start/stopp-styrning och en P-regulator som vanligen används i pumpstationer. Den tredje metoden var en Fuzzy-regulator som med hänsyn till nivån och nivåför-ändring reglerar varvtalet på pumpen.Resultatet från energitesterna visade att start/stopp-styrning förbrukade mest energi och att Fuzzy-regulatorn påvisade bäst egenskaper för att optimera energi-förbrukningen. Fuzzy-regulatorns energiförbrukning var mindre vid merparten av testerna jämfört med P-regulatorn. Fuzzy-regulatorn påvisade bäst egenskaper då inflödet var lågt relativt pumpens kapacitet och då bottenarean på sumpen var mindre.Vid undersökning av nya styrfunktioner har intervjuer av driftchefer utförts för att få en bild av problematiken som kan uppstå i en pumpstation. De styrfunktioner som utvecklats hade syftet att minska antalet förstoppade pumpar då detta var största problematiken. / This paper has investigated the possibility of optimizing the power consumption of pumps through the control system for a wastewater pumping stations. Further-more, the possibilities of developing new control functions has been investigated, with the purpose to simplify the operation maintenance of the station. To investigate energy consumption, a theoretical model of a pumping station has been made where energy tests for three different control methods have been per-formed. Two of the methods studied were on/off control and a P controller which are commonly used in pump stations. The third method was a Fuzzy controller which, with regard to the level and level change, regulates the speed of the pump.The results from the energy tests showed that on/off control consumed most en-ergy and the Fuzzy controller demonstrated best features to optimize energy con-sumption. The Fuzzy controller’s energy consumption was less in most of the tests compared with the P controller. The Fuzzy controller showed the best properties when the inflow was low relative to the pump’s capacity and the bottom area of the sump was smaller.When investigating new control functions, interviews with management executives has been made to get a picture of the problems that may occur in a pump station. The control functions developed had the purpose of reducing the number of clogged pumps as this was the biggest problem.

<ul> <li>Energy Optimization Stategies</li> <li>Hydraulic Models for Water Distribution Systems</li> <li>Heuristic Multi-objective Optimization Algorithms</li> <li>Multi-objective Optimization Problems</li> <li>System Constraints</li> <li>Encoding Techniques</li> <li>Optimal Pumping Operations</li> <li>Sovling Real-World Optimization Problems </li> </ul> / <p>The water supply industry is a very important element of a modern economy; it represents a key element of urban infrastructure and is an integral part of our modern civilization. Billions of dollars per annum are spent internationally in pumping operations in rural water distribution systems to treat and reliably transport water from source to consumers.</p> <p>In this dissertation, a new multi-objective optimization approach referred to as energy optimization strategy is proposed for minimizing electrical energy consumption for pumping, the cost, pumps maintenance cost, and the cost of maximum power peak, while optimizing water quality and operational reliability in rural water distribution systems. Minimizing the energy cost problem considers the electrical energy consumed for regular operation and the cost of maximum power peak. Optimizing operational reliability is based on the ability of the network to provide service in case of abnormal events (e.g., network failure or fire) by considering and managing reservoir levels. Minimizing pumping costs also involves consideration of network and pump maintenance cost that is imputed by the number of pump switches. Water quality optimization is achieved through the consideration of chlorine residual during water transportation.</p> <p>An Adaptive Parallel Clustering-based Multi-objective Particle Swarm Optimization (APC-MOPSO) algorithm that combines the existing and new concept of Pareto-front, operating-mode specification, selecting-best-efficiency-point technique, searching-for-gaps method, and modified K-Means clustering has been proposed. APC-MOPSO is employed to optimize the above-mentioned set of multiple objectives in operating rural water distribution systems.</p> <p>Saskatoon West is, a rural water distribution system, owned and operated by Sask-Water (i.e., is a statutory Crown Corporation providing water, wastewater and related services to municipal, industrial, government, and domestic customers in the province of Saskatchewan). It is used to provide water to the city of Saskatoon and surrounding communities. The system has six main components: (1) the pumping stations, namely Queen Elizabeth and Aurora; (2) The raw water pipeline from QE to Agrium area; (3) the treatment plant located within the Village of Vanscoy; (4) the raw water pipeline serving four major consumers, including PCS Cogen, PCS Cory, Corman Park, and Agrium; (5) the treated water pipeline serving a domestic community of Village of Vanscoy; and (6) the large Agrium community storage reservoir.</p> <p>In this dissertation, the Saskatoon West WDS is chosen to implement the proposed energy optimization strategy. Given the data supplied by Sask-Warer, the scope of this application has resulted in savings of approximately 7 to 14% in energy costs without adversely affecting the infrastructure of the system as well as maintaining the same level of service provided to the Sask-Water’s clients.</p> <p>The implementation of the energy optimization strategy on the Saskatoon West WDS over 168 hour (i.e., one-week optimization period of time) resulted in savings of approximately 10% in electrical energy cost and 4% in the cost of maximum power peak. Moreover, the results showed that the pumping reliability is improved by 3.5% (i.e., improving its efficiency, head pressure, and flow rate). A case study is used to demonstrate the effectiveness of the multi-objective formulations and the solution methodologies, including the formulation of the system-operational optimization problem as five objective functions. Beside the reduction in the energy costs, water quality, network reliability, and pumping characterization are all concurrently enhanced as shown in the collected results. The benefits of using the proposed energy optimization strategy as replacement for many existing optimization methods are also demonstrated.</p> / Doctor of Science (PhD)

L’hybridation électrique de la chaîne de traction automobile est l’une des solutions adoptées pour respecter les règlementations futures sur ses émissions. La stratégie de supervision de la chaîne de traction hybride répartit la puissance produite par le moteur à combustion interne et la machine électrique. Elle répond habituellement à un problème d’optimisation où l’objectif est de réduire la consommation de carburant mais nécessite à présent d’y ajouter les émissions polluantes. La chaîne de dépollution, placée à l’échappement du moteur, permet de diminuer la quantité de polluants émise dans l’atmosphère. Cependant, elle n’est efficace qu’à partir d’un seuil de température, et dépend de la chaleur apportée par les gaz d’échappement du moteur thermique. La première partie de ce travail est donc consacrée à la modélisation de la consommation énergétique et des émissions polluantes de la chaine de traction hybride. La modélisation de l’efficacité de la chaîne de dépollution est réalisée selon deux contextes. Le modèle zéro-dimensionnel est adapté aux contraintes de calcul de la commande optimale. Le modèle unidimensionnel associé à un estimateur d’état permet d’être embarqué et calculé en temps réel. À partir de ces travaux, la seconde partie de cette thèse déduit des stratégies de supervision à l’aide de la théorie de la commande optimale. Dans un premier cas, le principe de Bellman permet de calculer la commande optimale d’un véhicule hybride Diesel selon des critères de supervision ayant plus ou moins connaissance de l’efficacité de la chaîne de dépollution des émissions de NOX. Dans un second cas, une stratégie issue du Principe du Minimum de Pontryagin, embarquée sur un véhicule hybride essence, fonctionnant en temps réel et calibrée selon deux paramètres est proposée. L’ensemble de ces travaux est validé expérimentalement au banc moteur et montre une réduction significative des émissions polluantes pour une faible pénalité de carburant. / Powertrain hybridization is a solution that has been adopted in order to conform to future standards for emissions regulations. The supervisory strategy of the hybrid powertrain divides the power emitted between the internal combustion engine and the electric machine. In past studies, this strategy has typically responded to an optimization problem with the objective of reducing consumption. However, in addition to this, it is now necessary to take pollutant emissions into account as well. The after-treatment system, placed in the exhaust of the engine, is able to reduce pollutants emitted into the atmosphere. It is efficient from a certain temperature threshold, and the temperature of the system is dependent on the heat brought by the exhaust gas of the engine. The first part of this dissertation is aimed at modelling the energy consumption and pollutant emissions of the hybrid powertrain. The efficiency model of the after-treatment system is adapted for use in two different contexts. The zero-dimensional model conforms to the constraints of the optimal control calculation. The one-dimensional model associated with a state estimator can be embedded in a vehicle and calculated in real time. From this work, the second part of this dissertation deduces supervisory strategies from the optimal control theory. On the one hand, Bellman’s principle is used to calculate the optimal control of a Diesel hybrid vehicle using different supervisory criteria, each having more or less information about the after-treatment system efficiency over NOX emissions. On the other hand, a strategy from Pontryagin’s minimum principle, embedded in a gasoline hybrid vehicle, running in real time and calibrated with two parameters, is proposed. The whole of this work is validated experimentally on an engine test bed and shows a significant reduction in pollutant emissions for a slight fuel consumption penalty.

Dans le contexte du développement d’une agriculture durable, il est nécessaire d’optimiser le coût énergétique des opérations agricoles tout en garantissant des temps de travaux courts ainsi que la qualité des opérations réalisées. Cette question concerne en particulier l’opération du semis qui est déterminante pour la qualité de la future récolte. Les semoirs de grande capacité et à haute productivité conçus aujourd’hui se doivent d’être compatibles avec cet ensemble de contraintes. L’enjeu essentiel de cette thèse est donc d’élaborer une méthodologie innovante et utilisant des outils de modélisation dans le but de réduire la consommation énergétique des matériels de semis. En suivant cette logique, nous avons étudié quatre aspects clef de la conception des semoirs pneumatiques : la manœuvrabilité des semoirs poly-articulés, l’établissement des conditions du transport pneumatique des semences et des engrais, l’optimisation des systèmes de répartition des semences ou des engrais, et enfin les aspects énergétiques du mode d’introduction des semences dans le circuit pneumatique. Chaque modélisation a été précédée par une phase expérimentale de détermination des phénomènes majoritaires influençant le processus étudié. Ensuite une modélisation du processus étudié, basée sur la simulation des effets du phénomène majoritaire identifié a pu être mise en œuvre et des conclusions, appuyées par des essais expérimentaux, proposées quant à la conception des semoirs pneumatiques. L’étude de la manœuvrabilité des ensembles poly articulés a démontré qu’il était possible de proposer et de tester un modèle explicatif de prédiction de trajectoires adapté aux engins agricoles. Cette approche ouvre la voie à l’optimisation et à de nouvelles méthodes d’automatisation de manœuvres complexes, notamment des demi-tours en bout de champ. Il est par ailleurs possible de démontrer qu’une trémie en position arrière permet de réaligner plus rapidement la barre de semis après une manœuvre. L’étude des conditions du transport pneumatique a montré notamment que l’établissement de conditions de transport correctes au niveau des sorties de la tête de distribution conditionne l’ensemble de la conception du circuit de distribution de la matière. L’étude des systèmes de répartition des semences a permis d’expliquer l’origine des principaux défauts de répartition observés et notamment l’importance de l’adéquation entre le coude et la conduite verticale qui précède la tête de répartition des semences. Ces résultats ont ouvert la voie à l’étude de la mise en place de systèmes d’anticipation et de correction de ces défauts. Enfin l’étude comparée de deux systèmes d’introduction de la matière dans un circuit pneumatique a montré que du point de vue énergétique les systèmes pressurisés sont plus intéressants que les systèmes injecteurs. / In the context of sustainable farming, the optimization of the energy costs of agricultural operations allows shorter working times and high quality of the agricultural operations. This question relates particularly to the seeding. This operation one is decisive for the quality of the future harvest. The modern high capacity seed drills must be compatible with all the constraints. The main goal of this PhD thesis is thus to develop an innovative methodology, integrating the modeling tools, in order to reduce the energy consumption of the heavy seeding equipment. Thus, we explored four key aspects concerning air seed drill design: maneuverability of poly-articulated seed drills; establishment of the pneumatic conveying conditions of seeds and fertilizers; seed distribution accuracy optimization, and finally the energy aspects of the air stream loading systems. Each modeling was preceded by a preliminary experimental phase, defying the majority phenomena influencing the studied process. The modeling of the studied process and the conclusions (supported by experimental trials) have been proposed for the design of air seed drills. The study of maneuverability of poly-articulated agricultural machines showed that it was possible to get and test an explanatory model of trajectory prediction adapted for agricultural machines. This approach opens the way for optimization and automation of complex operations, including U-turns on headlands. We showed that a towed behind storage hopper (air-cart) allows faster realignment of the coulter bar after maneuvers. The study of pneumatic conveying conditions showed that the establishment of the correct conveying conditions in the outlets after the dispensing head defines the entire design of the distribution system. The study of seed distribution systems explains that the origin of the low distribution accuracy is caused in particular by the elbow and the vertical pipe before the dispensing head. These results open the way for the development of anticipation systems and correction of these defects. Finally the comparative study of two air-stream loading systems has showed that from the energy point of view the pressurized systems are more interesting than the injectors systems. / В рамках концепции устойчивого развития, необходимо учитывать энергетический аспект, сохраняя при этом эффективность использования рабочего времени и качества выполнения сельскохозяйственных операций. Особенно, это касается операции посева, определяющей в наибольшей степени будущий урожай. Современные широкозахватные зерновые сеялки и посевные комплексы вписываются в рамки устойчивого сельского хозяйства. Главной целью данной диссертации является разработка действенной методики проектирования пневматических сеялок, применяя методы моделирования и оптимизации, с целью уменьшения энергопотребления. Таким образом, мы использовали причинно-следственный подход для энергетической оптимизации четырех определяющих параметров: маневренность многозвеньевых посевных машин, обоснования необходимых условий пневмотранспорта, оптимизация распределения посевного материала, и ввода материала в магистральный трубопровод. В дополнение, снижение энергопотребления не должно сказываться на качестве выполнения технологического процесса посева. Моделирование каждого процесса, является следствием длительной экспериментальной фазы, посвященной определению наиболее значимых факторов, для каждого отдельного явления. В результате моделирований, симуляций и анализа, были составлены практические рекомендации, для конструкторов пневматических сеялок. Изучение маневренных характеристик многозвеньевых агрегатов позволило предложить и испытать физическую модель, позволяющую предопределить траекторию движение каждого звена машинно-тракторного агрегата. Такой подход позволяет автоматизировать выполнение наиболее сложных маневров (например, разворотов в конце гона). Кроме всего было показано, что заднеприцепные бункера позволяют более быстрое выравнивание агрегата после разворота. Изучение условий пневмотранспорта, позволило установить оптимальные, с точки зрения энергосбережения, параметры пневмотранспорта на выходе из распределительной головки, что послужило исходными данными для расчета характеристик пневмотранспорта в целом. Исследование процесса распределения семян в распределительной головке вертикального типа, позволило определить причины неравномерного распределения семян между выходными трубопроводами, в частности влияние отвода и вертикального трубопровода. На основании полученных данных, было предложена система устройств, позволяющих избежать возникновения завалов в системе, при минимальных энергопотерях. Сравнительные исследования двух систем ввода материала в магистральный трубопровод, позволили заключить, что питатели с наддувом являются менее энергоемкими по сравнению с питателями эжекторного типа.

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2016-10-25T22:46:25Z No. of bitstreams: 1 CUNHA_Marcel_2016.pdf: 12825811 bytes, checksum: fe0b61494670e2e5bcf510bf3689ef64 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2016-10-25T22:46:38Z (GMT) No. of bitstreams: 1 CUNHA_Marcel_2016.pdf: 12825811 bytes, checksum: fe0b61494670e2e5bcf510bf3689ef64 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2016-10-25T22:46:50Z (GMT) No. of bitstreams: 1 CUNHA_Marcel_2016.pdf: 12825811 bytes, checksum: fe0b61494670e2e5bcf510bf3689ef64 (MD5) / Made available in DSpace on 2016-10-25T22:46:59Z (GMT). No. of bitstreams: 1 CUNHA_Marcel_2016.pdf: 12825811 bytes, checksum: fe0b61494670e2e5bcf510bf3689ef64 (MD5) Previous issue date: 2016-02-22 / Não recebi financiamento / Nowadays smartphones are composed of a wide range of sensors and resources such as GPS (Global Positioning System), Bluetooth and Internet connection through Wi-Fi, 3G, among others resources. Along with the smartphone’s increasing popularity around the world, there is an increasing development and popularity of power-hungry applications: applications that take advantage from these resources and may reduce the smartphones autonomy. This fact is known as one of the biggest to be solved when talking about nowadays smartphones. Considering this, many solutions were proposed and approach this topic in different ways. These solutions can be classified in two major groups: software layer solutions and hardware layer solutions. In one hand, the software layer solutions are the ones that try to reduce the smartphone’s energy drain by only changing the software that composes the smartphone. For example, by improving the Wi-Fi interface or managing the running applications of the smartphone. On the other hand, the hardware layer solutions are the ones that try to improve or increase the energy availability of the smartphone changing or improving only the physical components, for example evolving the technology regarding the batteries. This study presents an approach in software layer for this problem: a system for managing the states of the smartphone’s sensors and components, based on the user profile, aiming energy savings. This work consisted of three steps. In the first step the literature research was done and also a research of the existing solutions in the same area. In the second step the mechanism, called MyBatRecommender, composed by the server and client sides, was presented and developed for the Android operational system. In the last step some validation tests were applied aiming to verify the system efficiency. The results show that when applied to a controlled scenario, the MyBatRecommender achieves around thirty-two per cent of energy savings. / Os smartphones atuais são compostos por uma grande gama de sensores e componentes como GPS, Bluetooth e conexão com a Internet através das interfaces de rede Wi-Fi, 3G, entre diversos outros recursos. Junto com a crescente popularização dos smartphones ao redor do mundo está também o crescente desenvolvimento e popularização dos aplicativos que fazem uso desses recursos e tendem a diminuir a autonomia dos smartphones. Esse fato é considerado como um dos maiores problemas a ser superado no contexto de smartphones atualmente. Tendo esse problema em vista, diversas soluções abordam a questão de diferentes maneiras, e podem ser classificados em dois grupos: soluções em nível de software e soluções em nível de hardware. As soluções em nível de software são aquelas que procuram melhorar o consumo de energia dos smartphones apenas com alterações nos softwares que compõe o smartphone. Por exemplo, melhorando a eficiência da interface de rede Wi-Fi, controlando aplicativos que rodam no smartphone, entre outras. Por outro lado, as soluções em nível de hardware procuram melhorar ou ampliar a disponibilidade de energia nos smartphones através dos seus componentes físicos, como por exemplo evoluindo a tecnologia das baterias dos mesmos. Esta dissertação apresenta uma abordagem em nível de software para esse problema através de um sistema de gerenciamento dos estados dos sensores e componentes de um smartphone, baseado no perfil do usuário, visando a economia de energia. Esse estudo consistiu de três etapas. Na primeira etapa foi feito o levantamento bibliográfico e desenvolvida uma pesquisa de soluções existentes na área, identificando possíveis sistemas e aplicativos com a mesma proposição. Na segunda etapa foi elaborado o mecanismo denominado MyBatRecommender, composto pelas partes servidora e cliente, e implementado para o sistema operacional Android. Por fim, na última etapa, foram aplicadas algumas formas de validação no sistema proposto a fim de verificar a sua eficiência. Os resultados obtidos mostram que o sistema implementado, quando aplicado em cenário de testes controlado, apresenta um resultado que traz uma economia de energia de aproximadamente trinta e dois por cento em relação ao uso sem o mecanismo proposto.

Les bâtiments commerciaux et industriels présentent une part non négligeable de la demande énergétique. L’objectif de ce travail de thèse est d’étudier par des simulations numériques, le comportement thermoaéraulique des bâtiments de grand volume à usage commercial ou industriel et d’améliorer leurs performances afin de réduire leurs consommations énergétiques tout en assurant le confort thermique des occupants. La première partie de l’étude consiste à définir et à évaluer les paramètres d’enveloppe et de ventilation qui affectent la consommation d’énergie et le confort thermique de ce type de bâtiment. À travers des modèles développés (multizone et zonal) sur un bâtiment « générique », nous présentons l’impact des paramètres les plus importants (orientation du bâtiment, isolation thermique de l’enveloppe, propriétés radiatives de la toiture, sol, inertie thermique interne, diffusion de l’air…) sur la consommation énergétique et le confort. Ces paramètres sont déterminants surtout dans la conception de la toiture et du plancher de par leur influence sur les performances énergétiques du bâtiment étudié. Cette modélisation thermoaéraulique est ensuite appliquée à un bureau-entrepôt commercial existant. L’exploitation du modèle, dont les résultats sont confrontés aux mesures, et des études paramétriques permettent de démontrer l’efficacité de stratégies de ventilation naturelle nocturne. Dans la deuxième partie, nous évaluons certaines solutions de rafraîchissement passif (isolation thermique, ventilation naturelle nocturne, revêtement de toiture « cool roof ») permettant de maintenir le confort thermique en hiver aussi bien qu’en été tout en minimisant la consommation énergétique. Enfin, une étude d’optimisation nous permet de déterminer les paramètres optimums en fonction des conditions climatiques et des deux objectifs de confort et de performance énergétique. Ce travail ouvre de nombreuses perspectives sur la méthodologie de conception des enveloppes et l’adaptation du fonctionnement des installations de ventilation pour le rafraîchissement passif des bâtiments. / Commercial and industrial buildings represent a significant part of total energy demand. The objective of this thesis is to study the thermal behavior and airflows of commercial or industrial buildings (low-rise and large volume) by numerical simulations, to improve their thermal performance in order to reduce their energy consumption while maintaining thermal comfort of the occupants. The first part of this study consists in identifying and evaluating the keys factors that affect the energy demand and thermal comfort of these buildings. Using the developed models (multizone and zonal), we present the impact of the most important parameters (building orientation, thermal insulation, radiative properties of the roof, soil, internal thermal inertia, air diffusion…) on energy consumption and thermal comfort. We have identified here that the main influencing parameters can be found in the design of the roof and the ground floor considering the energy performance of the studied building. The developed model is then applied to a real commercial building. Results showed that the predictions are in good agreement with the measurements and that night-time natural ventilation can be an efficient passive cooling technique to avoid overheating in summer. In the second part, we evaluate the efficiency of different passive cooling techniques (thermal insulation, night-time natural ventilation, cool roof…) applied to ensure the thermal comfort in winter as well as in summer while minimizing the energy consumption. Finally, an optimization study is proposed to determine the optimal set of parameters for both objective functions considering the passive cooling techniques and the energy demand according to different climatic zones.

Cooking is an integral part of each and every human being as food is one of the basic necessities for living. Commonly used sources of energy for cooking are firewood, crop residue, cow dung, kerosene, electricity, liquefied petroleum gas(LPG), biogas etc. Half of the world’s population is exposed to indoor air pollution, mainly the result of burning solid fuels for cooking and heating. Wood cut for cooking purpose contributes tothe16 million hectares(above4% of total area of India) of forest destroyed annually. The World Health Organization(WHO) reports that in 23 countries 10% of deaths are due to just two environmental risk factors: unsafe water, including poor sanitation and hygiene; and indoor air pollution due to solid fuel usage for cooking. In under-developed countries, women have to walk 2kms on average and spend significant amount of time for collecting the firewood for cooking. The cooking energy demand in rural areas of developing countries is largely met with bio-fuels such as fuel wood, charcoal, agricultural residues and dung cakes, whereas LPG or electricity is predominantly used in urban areas. India has abandon amount of solar energy in most of the regions making it most ideal place for harvesting solar energy. With almost 300 sunny days each year, one can confidently relay on this source of energy. India’s geographical location is in such a way that theoretically it receives 5x1015 kWh/ year of solar energy. Solar cooking is the simplest, safest, environmental friendly and most convenient way to cook. It is a blessing for those who cook using firewood or cow dung, who walk for miles to collect wood, who suffer from indoor air pollution. Hence solar cooking is going to play major role in solving future energy problem. Solar based cooking has never been a strong contender in the commercial market or even close to being a preferred method of cooking. They have been relegated to demonstration appliances to show case the solar based concepts. In this mode, cooking is no longer a time independent activity that can be performed at any time of day. One is forced to cook only at certain times when there is sufficient insolation. The geography of the cooking activity also shifts away from the kitchen. The kitchen is no longer the hearth of the home as the actual cooking activity shifts to the roof tops or high insolation platforms. This further adds to the inconvenience apart from being unable to cook at night or during cloudy conditions or during most of the winter days. Another issue of significant inconvenience is the general social structure in most families of the developing countries wherein the cooking activity is carried out by the senior ladies of the home. They are generally not athletic enough to be moving to and from the kitchen and the roof top to carry out the cooking exercise. As the solar cookers are enclosed spaces, interactive cooking is not possible let alone having any control on the rate of cooking. These are some of the more significant issues in the social psyche that has abundantly impeded the acceptance of solar thermal based cooking appliances. These issues and problems are in fact the motivating factors for this thesis. Based on these motivating factors, this thesis aims to propose solutions keeping the following points as the major constraints. cooking should be performed in the kitchen. one should be able to perform the cooking activity independent of the time of day or insolation. the cooking activity should be interactive the time taken for cooking should be comparable with the conventional methods in vogue. there should be a reduction in the use of conventional energy. Using the constraints and the motivating factors discussed above as the central theme, this thesis proposes a method to transfer solar thermal energy to the kitchen and act as a supplement to the conventional source of energy like the LPG or other sources that are traditionally being used in the households. The method proposed is in fact a hybrid scenario wherein the solar thermal is used to supplement the traditional source. Solar photovoltaic cells are also used to power the electronics and apparatus proposed in this thesis. This thesis addresses in detail the issues in analysis, modeling, designing and fabrication of the proposed hybrid solar cooking topology. The main goal of the proposed system is to transfer heat from sun to the cooking load that is located in the kitchen. The topology includes an additional feature for storing the energy in a buffer. The heat is first transferred from the solar thermal collector to a heat storage tank(that acts as the buffer) by circulating the heat transfer fluid at a specific flow rate that is controlled by a pump. The stored heat energy that is collected in the buffer is directed into the kitchen by circulating the heat transfer fluid into the heat exchanger, located in the kitchen. This is accomplished by controlling the flow rate using another pump. The solar thermal collector raises the temperature of the thermic fluid. The collector can be of a concentrating type in order to attain high temperatures for cooking. Concentrating collector like linear parabolic collector or parabolic dish collector is used to convert solar energy into heat energy. Absorption of energy from the incident solar insolation is optimized by varying the flow rate of circulating thermic fluid using a pump. This pump is energized from a set of photovoltaic panels(PV cell) which convert solar energy into electrical energy. The energy absorbed from the solar thermal collector is stored in a buffer tank which is thermally insulated. Whenever cooking has to be carried out, the high temperature fluid from the buffer tank is circulated through a heat exchanger that is located in the kitchen. The rate of cooking can be varied by controlling both the flow rate of fluid from the buffer tank to heat exchanger and also by controlling the amount of energy drawn from the auxiliary source. If the available stored energy is not sufficient, the auxiliary source of energy is used for cooking in order to ensure that cooking is in-dependent of time and solar insolation. In the proposed hybrid solar cooking system, the thesis addresses the issues involved in optimization of energy extracted from sun to storage tank and its subsequent transfer from the storage tank to the load. The flow rate at which maximum energy is extracted from sun depends on many parameters. Solar insolation is one of the predominant parameters that affect the optimum flow rate. Insolation at any location varies with time on a daily basis (diurnal variations) and also with day on a yearly basis(seasonal variation). This implies that the flow rate of the fluid has to be varied appropriately to maximize the energy absorbed from sun. In the proposed system, flow rate control plays a very significant role in maximizing the energy transfer from the collector to the load. The flow rate of the thermic fluid in the proposed system is very small on the order of 0.02kg/s. It is very difficult to sense such low flows without disrupting the operating point of the system. Though there are many techniques to measure very low flow rates, they invariably disrupt the system in which flow rate has to be measured. Further, the low flow sensors are far too expensive to be included in the system. A reliable, accurate and inexpensive flow measuring technique has been proposed in this thesis which is non-disruptive and uses a null-deflection technique. The proposed measuring method compensates the pressure drop across the flow meter using a compensating pump. The analysis, modeling, design and fabrication of this novel flow meter are addressed. The design and implementation of different subsystems that involves the selection and design of solar concentrating collector and tracking are explained. Finally, it is essential to know the economic viability of the proposed system that is designed and implemented. To understand the economics, the life cycle cost analysis of the proposed system is presented in this thesis. The major contributions of this thesis are: Energy transport: Major challenge in energy transport is to bring heat energy obtained from the sun to the kitchen for cooking. Energy transferred from solar insolation to the cooking load has to be optimized to maximize the overall efficiency. This can be split in to two parts,(a) optimizing efficiency of energy transferred from the collect or to the energy buffer tank,(b) optimizing efficiency of energy transferred from the buffer tank to the load. The optimization is performed by means of a maximum power point tracking(MPPT) algorithm for a specific performance index. Modeling of the cooking system: There are several domains that exist in the solar cooking system such as electrical domain, thermal domain, and hydraulic domain. The analysis of power/energy flow across all these domains presents a challenging task in developing a model of the hybrid cooking system. A bond graph modeling approach is used for developing the mathematical model of the proposed hybrid cooking system. The power/energy flow across different domains can be seamlessly integrated using the bond graph modeling approach. In this approach, the various physical variables in the multi-domain environment are uniformly de-fined as generalized power variables such as effort and flow. The fundamental principle of conservation of power/energy issued in describing the flow of power/energy across different domains and thus constructing the dynamic model of the cooking system. This model is validated through experimentation and simulation. Flow measurement: A novel method of low fluid mass flow measurement by compensating the pressure drop across the ends of measuring unit using a compensating pump has been proposed. The pressure drop due to flow is balanced by feedback control loop. This is a null-deflection type of measurement. As insertion of such a measuring unit does not affect the functioning of the systems, this is also a non-disruptive flow measurement method. This allows the measurement of very low flow rate at very low resolution. Implementation and design of such a unit are discussed. The system is modeled using bond graph technique and then simulated. The flow meter is fabricated and the model is experimentally validated. Design Toolbox: Design of hybrid cooking system involves design of multi domain systems. The design becomes much more complex if the energy source to operate the system is hybrid solar based. The energy budget has to be evaluated considering the worst case conditions for the availability of the solar energy. The design toolbox helps in assessing the user requirement and help designing the cooking system to fulfill the user requirement. A detailed toolbox is proposed to be developed that can be used in designing/selecting sub-systems like collector, concentrator, tracking system, buffer tank, heat exchanger, PV panel, batteries etc. The toolbox can also be used for performing life cycle costing.

The aim of the diploma thesis is to design austerity measures of an apartment building in the form of an energy card. The theoretical part deals with heat pumps. The computational part solves the evaluation of the current state of the building, the proposal of two variants, the assessment in terms of energy and economic and recommendations of the selected variant. There is also an experimental measurement specializing in thermovision imaging. The project contains energy certificates of individual states of the solved object.

The diploma thesis deals with the solutions of the renovation of a panel apartment building with regard to energy efficiency. The theoretical part deals with heat pumps. The acquired knowledge was subsequently applied in the computational part, where the energy assessment of the current state of the apartment building and the design of two possible variants of renovation are addressed. The aim of the first variant is the renovation of the building to meet classification class C using the possible funds. The second variant is focused on the technical equipment of the building and primary energy from renewable sources, so that the apartment building reaches classification class A. Both proposed variants are assessed from both an energy and financial point of view. The project part then contains certificates of energy intensity of individual variants of the building.