Diesel engines are commonly used in construction machines, for example excavators. In a diesel engine, the combustion of diesel is a process with a considerable environmental impact, with high amounts of emitted greenhouse gases. The bachelor thesis creates a model that investigates the potential of decreasing the environmental impact when replacing diesel engines with electric motors in the construction phase of the construction process of buildings. The model was made in three steps. In the first step the electric motors’ energy consumption were compared with the diesel engines’ energy consumption. Secondly, the results of the comparison were contrasted against the results of an implemented example as to determine the relevancy of the model. Finally, the carbon dioxide equivalent values of the diesel engines and the electric motors were calculated and compared. The result shows that there is a big potential of decreasing the environmental impact. The reduction is in the order of 63%-99% and it is shown that the share of renewable energy sources in the electricity mix is vital as to make the potential as large as possible.

To allow access to the network at all times a base station has to continuously stay active. While being active, a base station does not usually transmit data constantly. Typically, the base stations either send out lots of data or barely anything at all, yet, the network is actively drawing power the whole time. Succeeding in lowering the power consumed when the data rate is often so low would therefore lead to great benefits, both economically and environmentally, as well as new prospects of innovation in engineering. The process of how to dynamically change from a capacity optimized mode to an energy optimized mode as well as when to do this change is studied in this thesis for LTE. By using methods such as antenna muting and psi-omni coverage, the power consumption can decrease. These solutions however also decreases performance, and has to be activated with great care in mind not to cause any major impact on user performance. The dynamic configuration is dependent on the load of the system, changing to an energy efficient mode when traffic is low and to a capacity optimized mode when the network needs to supply high data rates. Simulations show that most energy savings can be found in rural and urban environments. Dynamic antenna muting achieved, summarizing macro environments, 24.9% energy savings with 95.27% downlink data rates compared to the reference case of using sector mode continuously i.e MIMO. In the same environments, dynamic psi-omni coverage together with antenna muting achieved energy savings of 43.8% with 89.3% downlink data rates compared to typical sector mode. Traffic rates are based on future demands in Europe by 2015, assuming that 20% of the subscribers are downloading 900 MB/h and the other 80% subscribers, at 112.5 MB/h.

This study explores ways to determine the energy efficiency of a pyrometallurgical ore reduction plant and measures to improve it. The feasibility of building a commercial plant - that is more energy efficient, has a low energy cost, and can operate independently and cost-effectively of external electricity supply - is determined. The need for energy efficiency is expanded to three questions: how should the energy efficiency of the plant be determined, what is the efficiency of the existing plant and to what level it can be improved. Literature and other relevant sources were consulted. Twenty potential energy conservation measures were identified through a literature study. A multi-criteria decision-making approach resulted in the selection of ten measures for conceptual implementation. The measures ranged from high-efficiency motors, solar power, heat recovery with thermal oil and various heat engines, to pressure recovery with turbo-generators. A case study approach was followed with the energy efficiency of an existing prototype plant the subject being studied. The energy usage of the existing plant and feasible measures to improve the performance were empirically observed. The impact of these measures was modelled and the results of the conceptual implementation determined. Two measures that were implemented during the study are also described and the results reported. The study found that the energy efficiency of the plant could be determined by the ratio of product exergy to input energy. By incorporating a number of energy conservation measures conceptually the internal efficiency of the prototype plant was conceptually improved from the current 17% to 22% and as a result externally supplied electricity reduced by 47%. The results were extrapolated to a future commercial plant and energy efficiencies of 26% on-grid and 21% off-grid predicted. This study suggests that a significant improvement in energy efficiency and energy cost can be achieved by integrating appropriate energy conservation measures into the existing and future plants. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Today, companies face a variety of environmental challenges, especially when it comes to evaluating energy consumption and minimizing environmental impact. This thesis examines how environmental management systems affects energy efficiency, and if it could contribute to sustainable development and increase corporate social responsibility. A case study research method was conducted on a multinational company and the empirical material is collected from the company's operations in China. The theoretical framework includes sustainable development, corporate social responsibility and environmental management systems. The results provide a model of calculation, in order to evaluate how the environmental management system affects energy efficiency. The analysis shows that the environmental management system has contributed to CSR practices in supporting the organization with guidelines toward continuous improvement of environmental impact, increased personal knowledge and some changes of production equipment. This has lead to that the case study company has managed to increase energy efficiency with respect to all energy sources, except water. / Företag stöter på allt fler utmaningar inom miljöområdet och inte minst när det gäller att utvärdera energianvändning och minimera miljöpåverkan. Denna uppsats handlar om hur miljöledningssystemet påverkar energieffektivitet samt om det kan bidra till en hållbar utveckling och kan leda till ett ökat samhällsansvar. Metodiken utgörs av en fallstudie på ett multinationellt företag, och det empiriska materialet är hämtat från en av koncernens fabriker i Kina. Det teoretiska ramverket omfattar huvudsakligen följande tre konsept: hållbar utveckling, företags samhällsansvar samt miljöledningssystem. Uppsatsen resulterar i ett förslag på beräkningsmodell för att utvärdera hur miljöledningssystemet har påverkat energieffektiviteten. Denna modell samt vilka faktorer som ligger bakom förändringar i energieffektivitet analyseras genom det empiriska materialet. Slutsatsen är att fallstudieföretaget har, genom ökad personalträning och uppgraderad produktionsanläggning, lyckats att öka energieffektiviteten med avseende på alla energikällor förutom vatten. / 企业面临更多的挑战在环境领域，尤其当涉及到评估能源使用，并尽量减少对环境的影响。这份报告是关于如何管理环境影响能源效率，这有助于实现可持续发展，并可能导致更大的社会责任。使用的方法是多的国际企业的案例研究和实证材料取自该公司在中国的业务。该理论框架包括可持续发展，企业社会责任和环境管理。论文导致提出的模型计算来评估环境管理体系影响能源效率。这种模式的背后改变能源效率的因素是由经验材料进行分析。得出的结论是，案例研究公司，通过增加人员培训和升级生产设施，管理，以提高能源利用效率相对于除水以外的所有来源。

MBA Professional Report / Approved for public release; distribution in unlimited. / The purpose of this research is to study the federal government's historical use of public-private partnerships (PPPs) and their view on the issue. Then we study recent applications (case studies) of innovative financing arrangements by Hannon Armstrong, LLC, an Annapolis, Maryland based financial services firm. The intention is to build upon previous Naval Postgraduate School research efforts is this subject; specifically, expanding upon the efforts of Professor San Miguel, Shank and Summers by investigating current examples of PPPs. First, we examine Hannon Armstrong's "fee for service contract" solution to the lack of appropriated capital funds needed for a vital fiber-optic link near the Arctic Circle. Then, we will explore the history of the Energy Saving Performance Contracts (ESPCs), which have been a useful tool in reducing the energy consumption throughout the federal government. Historically, this program has only been used for fixed assets. There is little debate over the success of these contracts in reducing energy consumption. The authors believe that applying Energy Saving Performance Contracts to mobile assets could further reduce the energy consumption of the Department of Defense (DoD) and save tax-payers millions of dollars.

Commercial buildings are among the largest consumers of energy. In an attempt to control and reduce operating expenses, building owners and organizations leasing commercial space are pursuing energy efficiency measures to generate a higher return on investment. In this study, an extensive literature review is used to identify and discuss energy efficiency considerations for medium-size building owners and how savings from these measures may benefit organizations through employee satisfaction and retention. For the purpose of this study, the specific topics related to commercial building energy efficiency that were investigated include (1) outcomes of building retrofits (2) corporate social responsibility and performance; (3) performance of energy efficient buildings; (4) employee commitment, satisfaction productivity and organizational profitability; (5) green companies and employee attraction; (6) the cost of turnover. There is little literature specifically focused on the impact that energy efficient buildings have on medium-sized building owners and no literature that quantifies the financial benefits through a reduction in employee turnover or attrition. Facility managers of all building sizes will benefit from gaining (1) a broad understanding of the impact of energy efficiency measures on employees (2) the ability to articulate the impact of the building’s role on employee productivity, turnover and other HR related issues (3) the insight needed to contribute to strategic discussions within their organization about how facilities can benefit organizational profitability. This research does not attempt to claim or determine a causal relationship between energy efficiency and employee turnover however it does discuss issues that that could affect employee attrition.. Further research to determine this causality would benefit the study of energy efficiency and its total impact on organizations.

It is expected that Wireless Body Area Network (WBAN) will greatly improve the quality of our life because of its myriad applications for our human beings. However, one of the challenges is to design energy efficient communication protocols to support the reliable communication as well as to prolong the network lifetime. Cooperative communications have the advantage of spatial diversity to combat multipath fading, thus improving the link reliability and boosting energy efficiency. In this thesis, we investigate the energy efficient cooperative communications for WBAN. We first analyze the outage performance of three transmission schemes, namely direct transmission, single relay cooperation, and multi-relay cooperation. To minimize the energy consumption, we then study the problem of optimal power allocation with the constraint of targeted outage probability. Two strategies of power allocation are considered: power allocation with and without posture state information. Simulation results verify the accuracy of the analysis and demonstrate that: 1) power allocation making use of the posture information can reduce the energy consumption; 2) within a possible range of the channel quality in WBAN, cooperative communication is more energy efficient than direct transmission only when the path loss between the transmission pair is higher than a threshold; and 3) for most of the typical channel quality due to the fixed transceiver locations on human body, cooperative communication is effective in reducing energy consumption.

Much of the existing commercial building stock is aging and will be in need of upgrades now or within the next twenty years. Typically, enclosure retrofits consist of adding insulation to the exterior or interior of the existing façade. In this thesis, an alternative solution is examined, whereby a glass façade is added to the exterior of the existing building, forming a double façade. For historic buildings, this could preserve and protect the existing façade without completely covering it up. For outdated buildings, this could modernize the existing façade, giving it the all-glazed appearance that is currently so popular among architects. Regardless of the retrofit motive, it is important to be able to quantitatively compare retrofit solutions to make informed design decisions. As such, building simulation can be an important design tool. At present, there is no available simulation tool that can easily and accurately model a double façade; therefore, a double façade (DoFa) model was developed to fill this gap. A spreadsheet-based, lumped model was created and validated using current complex fenestration models and limited experimental data. Further experimental data is required to validate all aspects of the model. Results showed that the DoFa model can achieve accurate results; however, further development is needed to predict optical properties of venetian blinds and convective coefficients for natural airflow in double façade cavities. The model was used to compare double façades to traditional glazing systems. Results indicated that double façades can perform comparably to double glazing with outdoor shading in summer, and triple glazing in winter. However, the results are only valid for the tested glazing systems. In a second application, the DoFa model was modified to simulate an entire enclosure to compare a double façade retrofit to more traditional retrofit strategies. Results suggested that a double façade provides a good improvement in winter performance, though summer overheating is a concern. For the case study examined, a double façade would have performed better than the chosen retrofit of replacing the windows with double glazing and indoor shading, without insulating the opaque components. The DoFa model can be very useful in creating double façade preliminary design and operation strategies. At present, the DoFa model is an instantaneous, stand-alone tool. Further development is needed to pair the DoFa model with whole building energy simulations.

Les xarxes de sensors sense fils (WSNs) han esdevingut un dels sistemes de comunicació amb més projecció d'aquesta dècada. Abasten una àmplia varietat d’aplicacions tals com la monitorització del medi ambient, la predicció de desastres naturals, en medicina, en transport, posicionament en interiors, i tasques militars. Els nodes que composen la xarxa, són típicament de baix cost, cosa que atorga una sèrie de limitacions en termes d’energia, velocitat de càlcul i d’ample de banda. Amb els avenços de les comunicacions sense fils i la creixent demanda de noves i més complexes aplicacions, les WSNs s’han d’optimitzar per tal de minimitzar aquestes limitacions. Aquesta tesi proposa un conjunt de tècniques que proporcionen a una WSN les següents característiques: 1. Implementació distribuïda sense necessitat de senyalització entre nodes sensors. 2. Comunicacions energèticament eficients. 3. Poca complexitat als nodes sensors. 4. Empra pocs recursos (temps, ample de banda, etc.) 5. Presenta un error quadràtic mig baix en reconstrucció al receptor. 6. Comunicacions secretes a capa física. Primer, s’estudia la transmissió seqüencial de mostreig reduït. Aquesta tècnica permet la disminució del nombre de transmissions i, per tant, reduir la despesa energètica associada a la comunicació a la xarxa. En particular, s’estudia el rendiment dels codificadors determinístics, probabilístics i condicionals de mostreig reduït per senyals autoregressius. S’obtenen expressions tancades de l’error quadràtic mig pel cas de mostreig reduït determinístic i probabilístic, mentre que pel cas condicional es deriven aproximacions ajustades. A continuació, s’analitza la compressió de la informació per WSNs grans. Pel cas on els paràmetres de correlació del senyal són desconeguts a priori, es proposen dos estimadors millorats: i) un per la predicció emprant el filtre de Wiener i ii) un per l’error quadràtic mig obtingut. Ambdós estimadors s’empren pels dos passos claus de l’algorisme de codificació distribuïda de canal. Aquests estimadors milloren notablement el rendiment de l’algorisme en comparació amb els estimadors de mostres clàssics, especialment quan la dimensió del vector d’observacions és comparable en magnitud amb el nombre de mostres usades a la fase d’entrenament de l’algorisme. Posteriorment, es proposa un esquema de comunicació distribuïda i energèticament eficient anomenat Amplify-and-Forward Compressed Sensing. Aquest esquema es basa en la tècnica de sensat comprimit i aprofita la correlació existent al senyal rebut per tal de reduir tant el nombre de recursos emprats com les despeses energètiques del sistema. Específicament, el sistema es dissenya seguint una funció de cost que controla el compromís existent entre error quadràtic i consum energètic de la xarxa. Per aconseguir aquest disseny, es deriva un model simple que aproxima el rendiment de l’esquema proposat en termes d’error quadràtic mig. A més, es contribueix a la teoria de sensat comprimit amb una nova i més ajustada relació entre el mínim nombre de mesures necessàries donades unes determinades propietats del senyal. Finalment, s’estudia l’esquema proposat Amplify-and-Forward Compressed Sensing des d’un punt de vista de secretisme a capa física. Es demostra que aquest esquema assoleix secretisme perfecte sota la presència d’un o d’un grup reduït d’espies, mentre que per un nombre més gran, és possible deteriorar notablement les seves capacitats d’espionatge gràcies a una tècnica proposta especialment dissenyada per introduir un extra d’incertesa solament a l’estimació dels espies. / Wireless Sensor Networks (WSNs) have emerged as one of the most promising wireless communication systems in the last decade. They can be used in a wide variety of applications such as environmental monitoring, natural disaster prediction, healthcare, transportation, indoor positioning, and military tasks. The cost and the complexity of the nodes within a WSN are typically low, which results in constraints such as energy limitation, low computational speed, and reduced communication bandwidth. With the advances in wireless communications and the growing demand of new and more complex applications, WSNs must be optimized in order to overcome their intrinsic limitations in terms of complexity and power. In this dissertation, and according to these constraints, we propose a set of techniques that provide to a WSN the following interesting features: 1. Distributed operation without the need of signaling among sensing nodes. 2. Energy-efficient communications. 3. Low complexity at the sensing nodes. 4. Low resource (i.e., bandwidth, time, etc.) utilization. 5. Low distortion level at the receiver. 6. Secret communications at the physical layer. First, we study the zero-delay downsampling transmission. This technique allows the system to reduce the number of transmissions and hence decrease the total energy spent. In particular, we study the performance of deterministic, probabilistic and conditional downsampling encoding-decoding pairs for the case of the autoregressive signal model. We obtain closed form expressions for the quadratic error of the deterministic and probabilistic encoder-decoders, while accurate approximations are derived for the quadratic error of the conditional downsampling schemes. Second, we analyze data compression applied to large WSNs. For the realistic case where the correlation parameters are not known a priori, we obtain two enhanced correlation estimators: i) one for the linear Wiener filter vector and ii) one for the achieved mean square error. Both estimators are employed in the two key steps of the distributed source coding algorithm. These estimators notably improve the performance of the algorithm in comparison to the application of classical sample estimators, specially when the dimension of the observation vector is comparable in magnitude to the number of samples used in the training phase. Then, we propose a distributed and energy-efficient communication scheme named Amplify-and-Forward Compressed Sensing. This scheme is based on compressed sensing and exploits the correlation present in the signal in order to reduce both the resource utilization and the energy consumption. More specifically, the system is designed according to a cost function that controls the trade-off between the quadratic error in the reconstruction and the energy consumption of the network. In order to aid the system design, a simple model that accurately approximates the performance of the proposed scheme in terms of the quadratic error has been derived. Furthermore, we contribute to the compressed sensing theory with a tighter relationship between the minimum number of measurements that are required for a given network dimension and the sparsity level of the transmitted signal. Finally, the proposed Amplify-and-Forward Compressed Sensing scheme is also studied in terms of secrecy and wiretap distortion at the physical layer. It is shown that the proposed scheme is perfectly secret in the presence of one or even a small group of eavesdroppers whereas for a larger eavesdropping set, it is still possible to notably deteriorate its espionage capabilities thanks to a proposed technique specifically designed to introduce extra uncertainty only in the channel estimation of the eavesdroppers.

This thesis is an investigation of why and how homeowners decide to renovate their homes. Energy efficient renovations are of particular interest given their potential contribution to public policy goals including greenhouse gas emission reduction. Policies seeking to improve energy efficiency in existing homes have to influence homeowners’ decisions. This requires a psychologically and behaviourally realistic understanding of the renovation decision process. Different research traditions offer competing models. These are tested through a series of hypotheses on the form and content of the renovation decision. The empirical dataset used combines both stated and revealed preference data. 809 homeowners in British Columbia were surveyed at three different cross-sections of the renovation decision process. The sample included both energy efficient (e.g., windows, insulation) and amenity renovators (e.g., kitchens, bathrooms), and was broadly representative of the population of renovating homeowners in British Columbia. Survey responses were calibrated using actual energy consumption data, and a supplementary survey of realtors. Calibration allowed homeowners’ expectations of the financial costs and benefits of renovating to be evaluated. Firstly, sampled homeowners systematically over-estimated their energy costs. Secondly, these estimates were subject to common information processing and recall biases. Thirdly, even homeowners in the middle of energy efficient renovations had expectations of capital costs, energy cost savings, and property value impacts that were largely unknown or unreliable. More generally, sampled homeowners lacked the basic knowledge necessary to appraise energy efficient renovations as financial investments. Homeowners’ motivations for renovating were more likely to be emotional and aesthetic in the case of amenities, but related to functional outcomes like thermal comfort in the case of energy efficiency. Social norms were influential in both cases but were underreported by homeowners. This was consistent with rationalisation biases which help individuals maintain self-esteem by emphasizing instrumental explanations for their actions. This psychologically realistic characterisation of the renovation decision suggests a range of design criteria for policy, and questions the effectiveness of narrowly-targeted information and incentive policies in their current form. However, policy implications should be generalised with caution given the low energy price and appreciating real estate market characteristics of the study region.