Recent advances in wireless communications along with developments in low-power circuit design and micro-electro mechanical systems (MEMS) have heralded the advent of compact and inexpensive wireless micro-sensor devices. A large network of such sensor nodes capable of communicating with each other provides significant new capabilities for automatically collecting and analyzing data from physical environments. A notable feature of these networks is that more nodes than are strictly necessary may be deployed to cover a given region. This permits the system to provide reliable information, tolerate many types of faults, and prolong the effective service time. Like most wireless systems, achieving low power consumption is a key consideration in the design of these networks. This thesis presents algorithms for managing power at the distributed system level, rather than just at the individual node level. These distributed algorithms allocate work based on user requests to the individual sensor nodes that comprise the network. The primary goal of the algorithms is to provide a robust and scalable approach for tasking nodes that prolongs the effective life of the network. Theoretical analysis and simulation results are presented to characterize the behavior of these algorithms. Results obtained from simulation experiments indicate that the algorithms can achieve a significant increase in the life of the network. In some cases this may be by an order of magnitude. The algorithms are also shown to ensure a good quality of sensor coverage while improving the network life. Finally, they are shown to be robust to faults and scale to large numbers of nodes. / Master of Science

Examining methods for controlling the electricity demand in Kuwait was the main objective and motivation of this researchp roject. The extensiveu se of air-conditioning for indoor cooling in office and large commercial buildings in Kuwait and the Gulf States represents a major part of the power and electricity consumption in such countries. The rising electricity generation cost and growing rates of consumption continuously demand the construction new power plants. Devising and enforcing Demand-SideM anagemen(t DSM) in the form of energye fficient operations trategies was the response of this research project to provide a means to rectify this situation using the demand-side management technique known as demand levelling or load shifting. State of the art demand-sidem anagementte chniquesh ave been examined through the developmenot f a model basedp redictive control optimisations trategyf or an integrateda ndm odulara pproachto the provisiono f ice thermals torage. To evaluate the potential of ice-storage assisted air-conditioning systems in flattening the demand curve at peak times during the summer months in Kuwait, a model of a Heating, Ventilation, and Air-conditioning (HVAC) plant was developed in Matlab. The model engaged the use of model based predictive control (MPQ as an optimisation tool for the plant as a whole. The model with MPC was developed to chose and decide on which control strategy to operate the integrated ice-storage HVAC plant. The model succeeded in optimising the operation of the plant and introduced encouraging improvement of the performance of the system as a whole. The concept of the modular ice-storage system was introduced through a control zoning strategy based on zonal orientation. It is believed that such strategy could lead to the modularisation of ice-storage systems. Additionally, the model was examined and tested in relation to load flattening and demonstrated promising enhancement in the shape of the load curve and demonstrated flattened demand curves through the employed strategy. When compared with measured data from existing buildings, the model showed potential for the techniques utilised to improve the load factor for office buildings.

Communications receivers that rely on 1-bit analogto-digital conversion are advantageous in terms of hardware complexity and power dissipation. Performance limitations due to the 1-bit quantization can be tackled with oversampling. This paper considers the oversampling gain from an information-theoretic perspective by analyzing the channel capacity with 1-bit quantization and oversampling at the receiver for the particular case of AWGN channels. This includes a numerical computation of the capacity and optimal transmit symbol constellations, as well as the derivation of closed-form expressions for large oversampling ratios and for high signal-to-noise ratios of the channel.

Examining methods for controlling the electricity demand in Kuwait was the main objective and motivation of this researchp roject. The extensiveu se of air-conditioning for indoor cooling in office and large commercial buildings in Kuwait and the Gulf States represents a major part of the power and electricity consumption in such countries. The rising electricity generation cost and growing rates of consumption continuously demand the construction new power plants. Devising and enforcing Demand-SideM anagemen(t DSM) in the form of energye fficient operations trategies was the response of this research project to provide a means to rectify this situation using the demand-side management technique known as demand levelling or load shifting. State of the art demand-sidem anagementte chniquesh ave been examined through the developmenot f a model basedp redictive control optimisations trategyf or an integrateda ndm odulara pproachto the provisiono f ice thermals torage. To evaluate the potential of ice-storage assisted air-conditioning systems in flattening the demand curve at peak times during the summer months in Kuwait, a model of a Heating, Ventilation, and Air-conditioning (HVAC) plant was developed in Matlab. The model engaged the use of model based predictive control (MPQ) as an optimisation tool for the plant as a whole. The model with MPC was developed to chose and decide on which control strategy to operate the integrated ice-storage HVAC plant. The model succeeded in optimising the operation of the plant and introduced encouraging improvement of the performance of the system as a whole. The concept of the modular ice-storage system was introduced through a control zoning strategy based on zonal orientation. It is believed that such strategy could lead to the modularisation of ice-storage systems. Additionally, the model was examined and tested in relation to load flattening and demonstrated promising enhancement in the shape of the load curve and demonstrated flattened demand curves through the employed strategy. When compared with measured data from existing buildings, the model showed potential for the techniques utilised to improve the load factor for office buildings.

Master of Science / Department of Computing and Information Sciences / Gurdip Singh / Severe energy constraints and limited computing abilities of the nodes in a network present a major challenge in the design and deployment of a wireless sensor network. This thesis aims to present energy efficient algorithms for data fusion and information aggregation in a sensor network. The various methodologies of data fusion presented in this thesis intend to reduce the data traffic within a network by mapping the sensor network application task graph onto a sensor network topology. Partitioning of an application into sub-tasks that can be mapped onto the nodes of a sensor network offers opportunities to reduce the overall energy consumption of a sensor network. The first approach proposes a grid based coordinated incremental data fusion and routing with heterogeneous nodes of varied computational abilities. In this approach high performance nodes arranged in a mesh like structure spanning the network topology, are present amongst the resource constrained nodes. The sensor network protocol performance, measured in terms of hop-count is analysed for various grid sizes of the high performance nodes. To reduce network traffic and increase the energy efficiency in a randomly deployed sensor network, distributed clustering strategies which consider network density and structure similarity are applied on the network topology. The clustering methods aim to improve the energy efficiency of the sensor network by dividing the network into logical clusters and mapping the fusion points onto the clusters. Routing of network information is performed by inter-cluster and intra-cluster routing.

The overall aim of this research project is to study green/energy-efficient real estate from an economic perspective. The thesis summarizes the results from five different studies with a connection to green/energy-efficient real estate.The aim of the first paper (paper A) is to study how tenants perceive the indoor environment in green-rated premises, and to compare these results with tenants’ perception of a conventional building’s indoor environment. The main result is that the tenants in the green-rated building are more satisfied with the indoor environment than the tenants in the conventional building.Papers B and C assess whether energy efficiency has an impact on buildings’ income and market values using Swedish real-estate data. The key result is that although there is a small impact on building-related income, this does not seem to translate into a higher market value.The last two papers included in this thesis study hindrances to a more energy-efficient building sector. In paper D, two office buildings are used as baseline cases to provide insights into the difficulties that can arise when trying to upgrade a building to make it more energy efficient. The results indicate that changing existing leases is a prohibitive process and that it is often difficult to evaluate the final impact of an energy upgrade. The last paper focuses on why it may be rational to postpone green refurbishments even if they are profitable. The main result is that it may be rational to postpone such refurbishments. However, by introducing different financial penalties and/or subsidies, these investments could be triggered today.To sum up, the results indicate that green buildings are preferred by tenants, but that there still appear to be economic barriers to a greener building sector. / Det övergripande syftet med denna avhandling är att studera grön/energieffektiva byggnader ur ett ekonomiskt perspektiv. Avhandlingen består av en kappa och fem separata studier, vilka belyser tre olika forskningsfrågor. Syftet med den första studien är att studera hur hyresgäster upplever inomhusmiljön i gröna byggnader. I studien jämförs inomhusmiljön i en grön byggnad med inomhusmiljön i en likvärdig konventionell byggnad. Resultatet visar, på det stora hela, att hyresgästerna är mer nöjda med inomhusmiljön i den gröna byggnaden. De nästföljande studierna, B respektive C, undersöker om byggnadens energiprestanda har någon inverkan på dess hyra respektive marknadsvärde. Resultaten visar på en liten signifikant hyrespåverkan, dock verkar denna inte ha någon effekt på byggnadernas marknadsvärdebedömningar. Skälet till detta kan vara att hyrespremien anses för liten för att ha någon signifikant inverkan på byggnadens marknadsvärde, alternativt att fastighetsvärderare inte beaktar energiprestanda när en fastighet värderas. De två sista studierna studerar varför vissa, tillsynes lönsamma, energiinvesteringar inte genomförs. Resultaten från studie D visar på svårigheterna med att ingå ett samarbetsavtal (för att eliminera felaktiga incitament) mellan hyresgäst och hyresvärd. Sådana avtal tar lång tid att förhandla fram och det uppkommer ofta svårigheter med att utvärdera de tänkta energiinvesteringarnas ekonomiska utfall. Studie E utgår ifrån en realoptionsmodell, vilken används för att utvärdera när ”gröna” renoveringar bör genomföras i en befintlig byggnad. Studien visar att det kan vara rationellt att vänta trots att investeringen idag är lönsam. Vidare visar resultaten att det är möjligt att via byggsubventioner/finansiella ”straff” påverka aktörer att tidigarelägga energieffektiviseringsåtgärder.  Dock är det viktigt att dessa utformas korrekt så att det inte skapar några snedvridna incitament. Övergripande visar resultaten att gröna byggnader är att föredra ur ett brukarperspektiv men att det fortfarande finns ekonomiska hinder för en mer hållbar byggsektor. Nyckelord: gröna byggnader, energieffektiva byggnader, EPC, inomhusmiljö, Realoptioner, fastighetsekonomi. / <p>QC 20160407</p>

One of prospective procedures of absorbing thermal energy and releasing it during the required time is the application of phase change materials known as PCMs in building envelopes. High thermal energy storage (TES) materials has been a technology that effects the energy efficiency of a building by contributing in using onsite resources and reducing cooling or heating loads. Currently, many TES systems are emerging and contributing in building assemblies, however using an appropriate type of TES in a specific building and climate requires an in-depth knowledge of their properties. This research aims to provide a thorough review of a broad range of thermal energy storage technologies including their potential application in buildings. Subsequently, a comparative study and simulation between a basecase and an optimized model by PCM is thoroughly considered to understand the effect of high thermal storage building's shell on energy efficiency and indoor thermal comfort. Specifically this study proposes that the incorporation of PCM into glazing system as a high thermal capacity system will improve windows thermal performance and thermal capacity to varying climatic conditions. The generated results by eQUEST energy modeling software demonstrates approximately 25% reduction in cooling loads during the summer and 10% reduction in heating loads during the winter for optimized office building by PCM in hot arid climate of Arizona. Besides, using PCM in glazing system will reduce heat gain through the windows by conduction phenomenon. The hourly results indicates the effect of PCM as a thermal energy storage system in building envelopes for building's energy efficiency and thermal regulation. However, several problems need to be tackled before LHTES can reliably and practically be applied. We conclude with some suggestions for future work.

No description available.

Significant advances have been made in the research and development of electric vehicles (EV’s). Along with the major challenge of energy storage, being also addressed is the efficient design of system energy transfer and consumption. This has had the effect of fundamentally changing perspectives across the mobility and transportation sector. Applied predominantly to road-going vehicles, the industrial context of non-road Electric Vehicles (nrEV’s) and specifically the use of manned electric forklift trucks integrated within the production related materials handling system has, to-date, received far less attention. The overarching aim of this research is to examine the impact and potential for the use of contactless occasional recharging of nrEV’s integrated within a manufacturing line, recognising the need to balance the (sometimes competing) demands of delivering sustainable production while exercising environmental responsibility. Meeting the objectives of this research resulted in the development of a location allocation model for electric charging station determination based on a fundamental understanding of the nature and quality of process inherent key performance indicators (KPI’s) as well as comprehensive process and energy monitoring while considering both Lean and Green Management perspectives. The integration of the generated knowledge and information into a generally valid simulation tool for occasional charging system implementation allows to more thoroughly investigate the impact from occasional charging to overall efficiency and sustainability to be realised. An investigation into relevant literature identified the need for specifically generated energy consumption data and confirmed the need for an energy optimisation model specific to the area of production related materials handling. Empirical data collected from repeated standardised materials handling operations within a selected production related materials handling environment resulted in the development of the Standard Energy Consumption Activity tool (SECA). Further work within this pilot study confirmed the tool as capable of generating reliable and valid data and confirmed the SECA tool as a generally applicable benchmark for energy consumption determination in material handling based on fractional process functions. Integrating this approach into a comprehensive process analysis and charging infrastructure optimisation resulted in the development of an Excel-based simulation model. The (Occasional Charging Station Location Model) OCSLM is based upon Maximal Covering Location Modelling and an endogenous covering distance definition in order to simulate process related potentials and optimal charging system implementation allocations, the target being to increase vehicles usable battery energy. A comprehensive case study based upon six individual and one combined data set confirmed the general and wider applicability of the OCSLM model while the application of the model provides a set of novel results. The application demonstrated a theoretical increase in usable battery energy of between 40% and 60% and within the same case study the impact of technology implementation identified that a reduction in battery and system cost of between 5% and 45% can be realised. However, the use of contactless power transfer resulted in an increase in CO2 emissions of up to 6.89% revealing a negative impact to overall ecology from the use of this energy transfer system. Depending on the availability of fast connecting, contact based energy transmission systems, the approach and results of OCSLM have shown to be directly applicable to contact based systems with resulting CO2 emissions decreasing by 0.94% at an energy transfer efficiency of 96%. Further novelty, of benefit to both academic and industry practice, was realised through the framework and information of the research with the provision of SECA as a process function-based and generally applicable energy consumption standard, OCSLM as a Maximal Covering Location Modell with a focus on occasional charging based on an endogenous covering distance and integrating detailed energy and process monitoring into electric charging station allocation, and the methodology for the application of this approach for fast connecting contactless and contact charging models and cases.

Les réseaux sans fil multi-sauts ad hoc et les réseaux de capteurs présentent une solution prometteuse pour assurer une connectivité quasi-permanente dans l'Internet du Futur. Cette connectivité, néanmoins, nécessite la conception d'un protocole d'accès au canal radio fiable, ce qui défi les caractéristiques hostiles et instables des réseaux ad hoc et des réseaux de capteurs. Cet environnement, en effet, est caractérisé par la rareté des ressources radio disponibles, la perte de la bande passante due aux collisions et aux interférences. La nécessité de garantir une meilleure qualité de service aux couches applicatives a promu la conception des protocoles MAC basés sur la technique d'accès TDMA. Essayant de contourner la contrainte d’une fine synchronisation horloge imposée par ce type de protocoles, les recherches se sont orientées vers une conception de protocoles MAC basés sur la technique TDMA dont la taille de la trame est fixe. Cependant, cette conception présente deux principaux inconvénients: d'une part elle procure une inflexibilité quant à la variation de la topologie du réseau suite aux mouvements des nœuds. D'une autre part, elle soulève un problème de dimensionnement : si la taille de la trame est surdimensionnée par rapport au nombre de nœuds présents dans le réseau, des slots non alloués apparaissent induisant la perte de la bande passante. Toutefois, si la taille de la trame est sous-dimensionnée, un risque de famine surgit. Les protocoles MAC basés sur la technique TDMA à taille de trame dynamique présentent une alternative, qui réussit à augmenter le débit au détriment d’une non-équité entre les nœuds dans le réseau. Outre l'utilisation optimale et équitable de la bande passante disponible, la réduction de la consommation d'énergie constitue un autre défi majeur pour les réseaux ad hoc et les réseaux de capteurs. Dans ce travail, deux contributions nommées OSTR et S-OSTR, sont conçues pour améliorer le débit, l'équité et la réduction de la consommation d'énergie dans l'environnement des réseaux ad hoc et des réseaux de capteurs. L'idée motrice d'OSTR consiste à augmenter la taille de la trame TDMA dynamiquement de manière à aboutir à une taille de trame réduite. Dans ce but, OSTR met en place une augmentation à la demande de la taille de la trame. Cette augmentation est établie slot par slot. OSTR se base sur une réutilisation spatiale des times slots ; i.e. un même slot peut être utilisé au même moment par plusieurs nœuds dans le réseau. Afin de prévenir les collisions dues à la coexistence de plusieurs tailles de trames au même temps dans le réseau, OSTR déploie une solution coopérative qui consiste à fixer un rendez-vous au moment duquel la taille de la trame est augmentée simultanément par tous les nœuds dans le réseau. S-OSTR constitue une adaptation du protocole OSTR à l'environnement des réseaux de capteurs. S-OSTR vise à augmenter la durée de vie du réseau. Il déploie ainsi une période d'activité dynamique qui consiste en une trame TDMA augmentant slot-par-slot. S-OSTR effectue également un ordonnancement des activités des nœuds afin de prolonger la période d'inactivité, et par suite prolonger la durée de vie du réseau. Nos deux contributions se basent sur une nouvelle technique d'augmentation dynamique de la taille de la trame TDMA qui consiste à augmenter la taille slot-par-slot. Cette technique permet d'atteindre une taille réduite, et par conséquent d’améliorer l'utilisation de la bande passante et de minimiser la consommation de l'énergie dans le réseau. L'analyse des performances d'OSTR et de S-OSTR souligne leurs potentiels pour s'adapter aux exigences des applications en termes de QoS, pour assurer un accès équitable au canal radio, pour réduire la consommation de l'énergie et pour s'adapter aux différents changements de la topologie du réseau / Wireless multi-hop ad hoc and sensor networks provide a promising solution to ensure ubiquitous connectivity for the Future Internet. Good network connectivity requires designing a reliable Medium Access Control (MAC) protocol, which is a challenging task in the ad hoc and sensor environments. The broadcast and shared nature of the wireless channel renders the bandwidth resources limited and expose the transmissions to relatively high collisions and loss rates. The necessity to provide guaranteed Quality of Service (QoS) to the upper layers triggered the design of conflict-free MAC protocols. The TDMA synchronization constraint is basically behind the rush of MAC protocol design based on a fixed frame size. This design shows inflexibility towards network variations and creates a network dimensioning issue that leads to a famine risk in case the network is under-dimensioned, and to a waste of resources, otherwise. Moreover, the alternative dynamic protocols provide more adaptive solutions to network topology variations at the expense of a fair access to the channel. Alongside with the efficient channel usage and the fair medium access, reducing the energy consumption represents another challenge for ad hoc and sensor networks. Solutions like node activity scheduling tend to increase the network lifetime while fulfilling the application requirements in terms of throughput and delay, for instance. Our contributions, named OSTR and S-OSTR, address the shortcomings of the medium access control protocol design in the challenging environment of wireless multi-hop ad hoc and sensor networks, respectively. For OSTR the idea consists in adopting a dynamic TDMA frame size that increases slot-by-slot according to the nodes arrival/departure to/from the network, and aiming to achieve a minimum frame size. For this end, OSTR couples three major attributes: (1) performing slot-by-slot frame size increase, (2) providing a spatial reuse scheme that favors the reuse of the same slot if possible, (3) and ensuring an on-demand frame size increase only according to the node requirements in terms of throughput. To tackle different frame sizes co-existence in the network, OSTR brings a cooperative solution that consists in fixing an appointment, a date when the frame size in the network is increased. Concerning S-OSTR, it is an amendment of OSTR for wireless sensor networks. It brings the idea of a dynamic active period, since it deploys a dynamic frame size that is built slot-by-slot according to nodes arrival to the network. S-OSTR enforces the slot-by-slot frame size increase by a node activity scheduling to prolong the inactivity period in the network, and hence prolong the overall network lifetime for wireless sensor networks. Our contributions are both based on the new dynamic TDMA frame size increase that consists in increasing the frame size slot-by-slot aiming to achieve a shorter frame size, and hence improve the channel utilization, and reduce the energy consumption. The performance analysis of OSTR and S-OSTR shows that they present good potentials to support QoS requirements, to provide energy-efficiency, to ensure fair medium access, to accommodate network topology changes and finally, to enhance robustness against scalability. The impact of this new TDMA frame size increase technique on the medium access control protocol performance is highlighted through multiple simulations of OSTR and S-OSTR. Multiple comparative studies are also handled to point out the effectiveness of this new technique and the soundness of our contributions