<p>Molecular separations are essential in the production of many chemicals and purified products. Of all the available separation technologies, distillation, which is a thermally driven process, has been and continues to be one of the most utilized separation methods in chemical and petrochemical plants. Although distillation and other commercial technologies fulfilled most of the current separation needs, the energy-intensive nature of many molecular separations and the growing concern of reducing CO₂ emissions has led to intense research to seek for more energy-efficient separation processes.<br></p><p><br></p><p></p> <p>Among the emerging separation technologies alternative to distillation, there is special attention on non-thermally driven methods, such as membranes. The growing interest in non-thermal methods, and particularly in the use of membranes, has been influenced significantly from the widespread perception that they have a potential to be markedly less energy-intensive than thermal methods such as distillation. Even though many publications claim that membranes are more energy-efficient than distillation, except for water desalination, the relative energy intensity between these processes in the separation of chemical mixtures has not been deeply studied in the literature. One of the objectives of this work focuses on introducing a framework for comparative analysis of the energy intensity of membranes and distillation. </p><p><br></p> <p>A complication generally encountered when comparing the energy consumption of membranes against an alternative process is that often the purity and recovery that can be achieved through a single membrane stage is limited. While using a multi-stage membrane process is a plausible solution to achieve both high purity and recovery, even for a simple binary separation, finding the most suitable multistage membrane process is a difficult task. This is because, for a given separation, there exists multiple cascades that fulfill the separation requirements but consume different amounts of energy. Moreover, the energy requirement of each cascade depends on the operating conditions. The first part of this work is dedicated to the development of a Mixed Integer Non-linear Program (MINLP) which allows for a given gaseous or liquid binary separation, finding the most energy-efficient membrane cascade. The permeator model, which is derived from a combination of the cross-flow model and the solution diffusion theory, and is originally expressed as a differential-algebraic equation (DAE) system, was integrated analytically before being incorporated in the optimization framework. This is in contrast to the common practice in the literature, where the DAE system is solved using various discretization techniques. Since many of the constraints have a non-convex nature, local solvers could get trapped in higher energy suboptimal solutions. While an option to overcome this limitation is to use a global solver such as BARON, it fails to solve the MINLP to the desired optimality in a reasonable amount of time for most of the cases. For this reason, we derive additional cuts to the problem by exploiting the mathematical properties of the governing equations and from physical insights. Through numerical examples, we demonstrate that the additional cuts aid BARON in expediting the convergence of branch-and-bound and solve the MINLP within 5%-optimality in all the cases tested in this work.</p><p><br></p> <p>The proposed optimization model allows identifying membrane cascades with enhanced energy efficiency that could be potentially used for existing or new separations. In addition, it allows to compare the optimum energy consumption of a multistage membrane process against alternative separations methods and aid in the decision of whether or not to use a membrane system. Nevertheless, it should be noted that when a membrane process or any other non-thermal separation process is compared with a thermal process such as distillation, an additional complication often arises because these processes usually use different types of energies. Non-thermal processes, such as membranes, consume electrical energy as work, whereas thermal processes, such as distillations, usually consume heat, which is available in a wide range of temperatures. Furthermore, the amount of fuel consumed by a separation process strongly depends on how its supplied energy is produced, and how it is energy integrated with the rest of the plant. Unfortunately, common approaches employed to compare the energy required by thermal and non-thermal methods often lead to incorrect conclusions and have driven to the flawed perception that thermal methods are inherently more energy-intensive than non-thermal counterparts. In the second part of this work, we develop a consistent framework that enables a proper comparison of the energy consumption between processes that are driven by thermal and non-thermal energy (electrical energy). Using this framework, we refute the general perception that thermal separation processes are necessarily the most energy-intensive and conclusively show that in several industrially important separations, distillation processes consume remarkably lower fuel than non-thermal membrane alternatives, which have often been touted as more energy efficient.</p><p><br></p> <p>In order to gain more understanding of the conditions where membranes or distillation are more energy-efficient, we carried out a comprehensive analysis of the energy consumed by these two processes under different operating conditions. The introduced energy comparison analysis was applied to two important separation examples; the separation of p-xylene/o-xylene, and propylene/propane. Our results showed that distillation is more energy favored than membranes when the target purity and recovery of the most volatile (resp. most permeable) component in the distillate (resp. permeate) are high, and particularly when the feed is not too concentrated in the most volatile (resp. most permeable) component. On the other hand, when both the recovery and purity of the most volatile (resp. most permeable) component are required at moderate levels, and particularly when the feed is highly enriched in the most volatile (resp. most permeable) component, membranes show potential to save energy as compared to distillation.</p>

Access networks have been going through many reformations to make them adapt to arising traffic trends and become better suited for many new demanding applications. To that end, incorporating fog and edge computing has become a necessity for supporting many emerging applications as well as alleviating network congestions. At the same time, energy-efficiency has become a strong imperative for access networks to reduce both their operating costs and carbon footprint. In this dissertation, we address these two challenges in long-reach optical access networks. We first study the integration of fog and edge computing with optical access networks, which is believed to form a highly capable access network by combining the huge fiber capacity with closer-to-the-edge computing and storage resources. In our study, we examine the offloading performance under different cloudlet placements when the underlying bandwidth allocation is either centralized or decentralized. We combine between analytical modeling and simulation results in order to identify the different factors that affect the offloading performance within each paradigm. To address the energy efficiency requirement, we introduce novel enhancements and modifications to both allocation paradigms that aim to enhance their network performance while conserving energy. We consider this work to be one of the first to explore the integration of fog and edge computing with optical access networks from both bandwidth allocation and energy efficiency perspectives in order to identify which allocation paradigm would be able to meet the requirements of next-generation access networks.

One of the most urgent challenges of the 21st century is to investigate new technologies that can enable a transition towards a society with a reduced CO2 footprint. Information Technology generates about 2% of the global CO2, which is comparable to the aviation industry. Being connected to the Internet requires active participation in responding to protocol messages. Billions of dollars worth of electricity every year are used to keep network hosts fully powered-on at all times only for the purpose of maintaining network presence. Most network hosts are idle most of the time, thus presenting a huge opportunity for energy savings and reduced CO2 emissions. Proxying has been previously explored as a means for allowing idle hosts to sleep yet still maintain network presence. This dissertation develops general requirements for proxying and is the first exploration of application-level proxying. Proxying for TCP connections, SIP, and Gnutella P2P was investigated. The TCP proxy keeps TCP connections open (when a host is sleeping) and buffers and/or discards packets as appropriate. The SIP proxy handles all communication with the SIP server and wakes up a sleeping SIP phone on an incoming call. The P2P proxy enables a Gnutella leaf node to sleep when not actively uploading or downloading files by handling all query messages and keyword lookups in a list of shared files. All proxies were prototyped and experimentally evaluated. Proxying for P2P lead to the exploration of space and time efficient data structures to reduce the computational requirements of keyword search in the proxy. The use of pre-computation and hierarchical structures for reducing the false positive rate of a Bloom filter was explored. A Best-of-N Bloom filter was developed, which was shown to have a lower false positive rate than a standard Bloom filter and the Power-of-2 Bloom filter. An analysis of the Best-of-N Bloom Filter was completed using Order Statistics to predict the false positive rate. Potential energy savings are shown to be in the hundreds of millions of dollars per year assuming a modest adoption rate of the methods investigated in this dissertation. Future directions could lead to greater savings.

Efficient use of resources and utility is the key to reduce the price of the commodities produced in any industry. This in turn would lead to reduced price of the commodity which is the key to success. Sustainability involves integration of all the three dimensions: environmental, economic and social. Sustainable manufacturing involves the use of sustainable processes and systems to produce better sustainable products. These products will be more attractive, and the industry will know more about the climate impact from their production.   Manufacturing companies use a considerable amount of energy in their production processes. One important area to understand the sustainability level at these types of industries is to study this energy use. The present work studies energy use in a large-scale tool manufacturing company in Sweden. Value Stream Mapping method is implemented for the purpose of mapping the energy use in the different operations. To complement this, an energy audit has been conducted, which is a method that include a study and analysis of a facility, indicating possible areas of improvements by reducing energy use and saving energy costs. This presents an opportunity for the company to implement energy efficiency measures, thus generating positive impacts through budget savings. Less energy use is also good for the environment resulting in less greenhouse gas emissions level. This also helps in long-term strategic planning and initiatives to assess the required needs and stabilize energy use for the long run. Social sustainability completes the triad along with environmental and economic sustainability. In this study, the latter is reflected with the company’s relationship with its working professionals, communities and society.

El sector MIPYME (Micro, Pequeña y Mediana empresas), representa el 99.5% de empresas formales. El 96.2% son microempresas, 3.2% pequeña y 0.1% mediana (Ministerio de la Producción, 2017). El sector manufactura evoluciona constantemente y para ello requiere incorporar el uso de maquinaria especializada, dicha maquinaria opera principalmente con energía eléctrica. En 2015, el mayor consumo de energía se registró en el sector minero e industrial con 56% (22 440 GWh) del total a nivel nacional. Con respecto a 1995, el consumo del sector minero e industrial se incrementó 466% (Osineming, 2016). Por su lado, la producción de energía eléctrica no ha crecido con la misma magnitud, lo que ha ocasionado el aumento del costo del servicio. Por ejemplo, el cargo por energía activa para Lima Norte se ha incrementado 42% en el periodo 2005-2016 al pasar de 32.8 ctm S/. por kWh a 46.6 ctm S/. por kWh (Osineming, 2016). Actualmente la implementación de medidas de eficiencia energética, particularmente en energía eléctrica, requieren de personal especializado y son ejecutadas como parte de labores de mantenimiento en periodos definidos. Se propone el uso del IoT (Internet of Things) para identificar medidas de eficiencia energética desde una aplicación web, la que puede ser manejada por personal no especializado. El objetivo es definir una línea base de consumo y monitorear el consumo de energía eléctrica, para luego enviar alertas en real cuando el consumo se aleje de la línea base de consumo definida, de manera que el responsable pueda tomar las acciones correctivas necesarias inmediatamente y reducir la facturación generada por uso indebido de energía eléctrica. Estimamos que nuestro servicio tendrá un pago mensual de US$ 520.00, para su inversión estimamos se requiere de $250,000.00. Resultando un VAN de US$ 330 mil y una TIR de 41%, lo que resulta atractivo para inversionistas. / The micro, small and medium-sized businesses (MIPYME, as abbreviated in Spanish) represent 99.5% of formal businesses in Peru. Out of this number, 96.2% are micro, 3.2% are small and 0.1%, medium businesses (Peruvian Ministry of Production, 2017). The manufacturing sector is constantly evolving, which requires incorporating the use of specialized machinery. Such machinery operates mainly with electrical energy. In 2015, the highest energy consumption was recorded in the mining and industrial sector totaling 56% (22,440 GWh) at a national level. The consumption of the mining and industrial sector has increased 466% when compared to 1995 figures (Osinergmin, 2016). Meanwhile, the production of electrical energy has not grown to match these consumption rates, which has caused the costs of the service to increase. Energy costs for northern Lima have increased in 42% from 2005-2016 (actual cost of S/ 46.60 ctm/kWh from S/ 32.80 ctm/kWh) according to Osinergmin (Osinerming, 2016). Currently, the implementation of energy efficiency measures, particularly for electric energy, require specialized staff and are executed as part of maintenance work that takes place at specified times. This paper proposes the use of the IoT (Internet of Things) to identify energy efficiency measures from a web application, which can be handled by non-specialized staff. The objective is to define a baseline consumption and monitor the consumption of electrical energy. As consumption moves away from this baseline, alerts should prompt corrective actions that reduce the turnover generated by excessive electric power. We believe that our service will have a monthly fee of US$ 520.00. A total of US$ 250,000.00 has been calculated as total investment. In addition, an NPV of approximately US$ 330K and an IRR of 41% make it attractive to potential investors. / Trabajo de investigación

Herrenknecht AG is a German world-leading Tunnel Boring Machines manufacturer showing strong awareness and concern regarding environmental issues. The company supports research on the Energy Efficiency (EE) of their products, aimed at the development of intelligent design for a green Tunnel Boring Machine. The aim of this project is to produce a ’status quo’ report on EE of three types of Tunnel Boring Machines (Hardrock, EPB and Mixshield TBM). In the framework of this research 39 projects are analysed using calculation tools, plotting and statistical functionalities of Excel and Matlab. The findings of this study inter alia confirm the existence of data quality issue and highlight the necessity of data quality control, allow identification of specific distinctions between energy consumption of the three investigated TBM types, and stress the necessity for optimisation of the layout of TBMs energy supply units and main consumers. Moreover the results of the survey suggest that there is a certain energy saving potential, which is achievable by e.g. an adequate selection of the machine type prior to start of a given project and better adjustment of the machines’ layout to the particular local geological environments. An EE implementation strategy, indicating further research needs, is suggested and discussed.

This project has been carried out for the ALEC (Agence Locale de l'Energie et du Climat) of Grenoble urban area, a French energy and climate agency. It has been composed of several missions, all related to energy management in residential buildings. First, an annual energy use assessment have been conducted for two different building samples:  the eco-district of De Bonne in Grenoble and a sample of about 25 social housing buildings over the region. These two assessments showed that the average energy performance of newly built buildings is improving every year, notably under the stimulation of innovative projects such as De Bonne. Then, a more precise follow-up of construction and renovation social housing projects enabled to learn more about how to maintain energy facilities and to detect some common technical issues. The global conclusion of this project is that, although buildings are better designed today, energy performance remains fragile notably during construction and operation. To cope with that, some solutions exist and should be more systematically applied in future construction or renovation projects.

Detta examensarbete har genomförts i samarbete med Värmex AB där vi har haft Anders Ericsson som handledare, och Peter Hansson (Sweco) som handledare från skolan, Kungliga tekniska högskolan i Haninge. Idag är energianvändningen i flerbostadshus en stor fråga att ta itu med, och för varje byggnadsprojekt skall en energideklaration som visar mängd köpt energi göras. Vi strävar idag efter att minska energianvändningen i flerbostadshus med 50 % till 2050. I denna analys beskriver vi vilka åtgärder man kan ta an för att minska just energianvändningen i ett specifikt flerbostadshus belägen i kommunen Nacka i Stockholm. Då denna byggnad stått från år 1949 utan större underhållning har det visat sig att byggnaden står över BBRs krav gällande energianvändning (90 kWh/m2), och stor anledning är klimatskalet. Källor visar även att delar av klimatskalet så som fasad etc. bör ändras inom 30 år efter det att det byggts, vilket inte har gjorts. Vi har genom en programvara, VIP-Energy valt att utföra denna analys. Med hjälp av offentliga handlingar från stadsbyggnadskontoret så som plan – sektion – fasadritningar har vi mätt nödvändiga mått som vi knappat in i programmet. Även information som byggnadsmaterial, läge på byggnaden och uppvärmningssystem har varit nödvändiga. Jämförelse mot BBRs krav har gjorts automatiskt i programmet och det är sådan slags information vi utgått ifrån.  Då vi i denna analys valt att fokusera på klimatskal där tak, golv, väggar, fönster och dörrar ingår visar resultatet att lägre u-värden på byggnadsdelar bidrar till lägre energianvändning. Studier visar att ca 35 % av värmeförlusterna är via fönster, och detta överensstämmer med byggnaden som denna analys är baserad på. Som lösning till detta har vi valt att byta fönster till 2-glas fönster med isolleruta vilket har betydligt lägre u-värde än de vi har idag. Vi vill även förbättra karmen och fogen kring fönstren för att minska transmissionsförlusterna och eventuella drag i bostäderna, vilket i sin tur leder till bättre komfort och skönare atmosfär. Detsamma gäller yterdörrarna som behöver bytas för att hålla värmen inne. Utvändig isolering i ytterväggen bidrar även med förbättringar kring u-värde och energianvändning. Originalhuset visade att byggnadens genomsnittliga U-värde ligger på 0,656W/m2K och energianvändningen ligger på 96 kWh/m2 per år. Enligt BBRs krav för äldre byggnader ska u-värdet ligga på 0,400W/m2K och energianvändningen på 90kWh/m2 per år. Energibalansberäkningen visar nya värden på byggnaden, vilket är totala u-värde på 0,409 W/m2K samt energianvändningen på 64 kWh/m2. / This degree project has been written in collaboration with Värmex AB, with the generous help of Anders Ericsson as our fellow adviser and Peter Hansson (Sweco) our mentor from the Royal institute of technology located in Haninge.   Today we find questions pertaining to energy consumption in apartment blocks of real significance; with each building project a declaration that shows the amount of energy consumed is of outmost importance. We strive to reduce energy consumption in apartment blocks by 50 % until year 2050. In this degree thesis, we aim to describe measures and solutions to lower the consumption of energy in a specific apartment block located in Nacka, Stockholm.   This building has been standing quite untouched and unmarked since 1949, yet it is still in compliance with the demands stated by BBR concerning energy efficiency, in large because of its climate shell. Sources show that greater parts of its outer shell for example the front, should have been repaired during the first 30 years, and the matter is still to be solved. The use of a computer software VIP-Energy has enabled us to state a hypothesis. With the help of public documents from Housing And Urban Development Town Building Office (HUD) giving us an overview of the different dimensions of the building, we've been able to plot all this data into the software. Information such as building materials, location, heating systems have also been necessary in our analysis. Results are automatically compared to the demands required by BBR. It is through experimentation of this data that we have been successful in collecting our results.  In the analysis, we chose to focus on the climate shell that constitutes: roof, floors, walls, windows and doors. Our results show that lower U-values conduce better energy efficiency. Studies show that almost 35 % of energy loss in a building is caused by the windows of the building, this this is consistent with the building which this analysis is based on. We have solved this by changing sheet glass that is energy efficient. We also aim to change the frame and seams surrounding the windows, in order to lower transmission losses and possible draughts in the apartments. This will result in hopefully a higher degree of comfort and refreshing atmosphere. The same changes apply to entry doors in order to keep energy loss to a minimum. Also an external insulation in the outer wall contributes to improvements on u-value and use.  The original building shows an average U-value of 0,656W/m2K and the energy consumption is 96 kWh/m2 per year. According to BBR, older buildings should have a U-value of 0,400W/m2K and an energy consumption of 90kWh/m2 per year. Energy balance calculation show new values for the building were the u -value should be set to 0,409W/m2K, and energy consumption should be set to 64kWh/m2.

Residential and commercial buildings consume approximately 20% of the global energy generation. This value is continuously growing and the governments across the globe have realized the importance of regulating the building construction to optimize the energy utilization. Energy efficient building codes have been developed to optimize the energy efficiency in buildings. OTTV (Overall Thermal Transfer Value) is a key parameter for evaluating energy efficiency of building envelops in the present building code of Sri Lanka. In this research, the prescriptive requirements mentioned in the building code for the building envelops to optimize the energy efficiency of five (05) commercial buildings has been analyzed. The indoor climate was modeled and the annual cooling energy variation with Overall Thermal Transfer Value was studied using “DesignBuilder” software. A cost benefit analysis was carried out for enhanced energy efficiency building envelops applications. It was attempted to develop a general relationship between the OTTV and annual cooling energy requirement for each building. It has been observed that a second order polynomial relationship with R2 of 0.861 exists for RDA building, linear relationship with R2 of 0.838 exists for AirMech building. However a specific relationship could not be observed for BMICH, SLSI and WTC buildings. The impact on cooling energy requirement from envelop parameter modification is unique for each building. In some instances the reduction of OTTV has not resulted in any reduction of the cooling energy requirement. There is a combined effect from each building component which affects the final cooling energy requirement. A simulation based technique to be used to find the optimum building envelops design.

Winter road maintenance activities are crucial for maintaining the accessibility and traffic safety of the road network during winters. Common winter road maintenance activities include plowing and the use of de-icing agents (e.g. NaCl) to avoid freezing. Effective winter road maintenance strives towards keeping the roads free from snow and ice while reducing negative side effects of winter road maintenance, such as ground water contamination from road salt. Since the weather is decisive for when there is an increased risk of slipperiness, the understanding and continuous observation and forecasts of the road weather are of highest importance. Sensors are commonly installed along roads to measure road weather conditions to support the road maintenance personnel in taking appropriate actions. Different types of errors and uncertainties related to sensors used for frost warnings along roads have been investigated by using a regional scale dataset from south-western Sweden. The results from this study indicate that various types of uncertainties originate from both measurements and models which have a significant impact on the winter road maintenance efficiency. To provide better information about the road surface conditions, a new method for detecting ice formation on roads is presented. Infrared sensors were used to detect temperature patterns which may occur when ice formation take place on a road surface. The investigations demonstrate the potential to improve winter road maintenance by introducing new methods to better describe the road surface conditions. / QC 20101206