Дисертації з теми "Energy efficiency management system"

Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 62).
The following gaps in critical goals are derived through a direct comparison of the Needs to Goals transformation versus the current waste heat recovery solutions and their stated goals. 1. Critical: Implementation of a sustainable financial plan which can help to initiate an increase in waste heat recovery 2. Critical: Deployment of waste heat recovery strategies for reducing greenhouse emissions A proposed solution to achieve these two goals would be: 1. Purchasing waste heat from industries. 2. Storing this energy with our proprietary thermal storage materials. 3. Selling the stored energy at either industrial sites or to pricier markets. New thermal-storage materials and a mini-sized combined heat and power (CHP) system have been further developed. This system will be the first to involve the arbitrage of waste heat energy by using cheap thermal storage material (made with zero greenhouse emissions) and a mini generator. This system could play an important role in providing economic incentives for industries that wish to recover waste heat.
by Chia-Chi (Jacky) Chen.
S.M. in Engineering and Management

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program; in conjunction with the SDM Fellows Program, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 65-66).
The optimal air temperature for datacenters is one of ways to improve energy efficiency of datacenter cooling systems. Many datacenter owners have been interested in raising the room temperature as a quick and simple method to increase energy efficiency. The purpose of this paper is both to provide recommendations on maximizing the energy efficiency of datacenters by optimizing datacenter temperature setpoint, and to understand the drivers of datacenter costs. This optimization and the potential energy savings used in cooling system can drive higher energy use in IT equipment and may not be a good trade off. For this reason, this paper provided a detailed look at the overall effect on energy of temperature changes in order to figure out the optimal datacenter temperature setpoint. Since this optimal temperature range varies by equipment and other factors in the datacenter, each datacenter should identify its appropriate temperature based on the optimization calculation in this paper. Sensitivity analysis is used to identify the drivers of the cost of ownership in a datacenter and to identify opportunities for datacenter efficiency improvement. The model is also used to evaluate potential datacenter efficiency.
by Heechang Lee.
S.M.in Engineering and Management

When speaking about energy it means speaking about life, activity, economy, growth and environmental issues. The issue of energy has been the main article all over the world in recent years, this is due to the importance of energy to life and its impact on the environment. For example, Paris climate change meeting in 2015 is one of the recent global meeting which directly related to the energy use by nations. The meeting was mainly focused up on the restriction of greenhouse gas emission which implies that industries should think about other alternative energy resources rather than fossil fuel for positive impact on climatic change. This is one of the cases that led industries into greater competition in the global market. Industries must consider energy alternatives which is safe for the environment and by using such energy a competitive product with better quality and quantity should be produced. This challenge has motivated industries to look and study the energy that they are using currently. Studies and researches show that one of the main and most abundant energy resources that most of these industries can get is by improving the energy efficiency or managing the energy that they currently use. The main aim of this thesis is to provide Arizona chemical plant (Kraton) at Sandarne on the potential energy saving by managing their energy use. The first wisdom in energy utilization is managing and using the energy they possess efficiently. In Arizona plant at Sandarne, the product named “Pitch” (a natural viscoelastic polymer or rosin) is a fuel used as the primary energy supply for the production of steam by boilers. The steam may be utilized well but the energy in the condensate (after steam loses its latent heat) is not addressed well enough. Hence this paper has studied on how significant is the energy lost by the steam condensate is and how its recovery can be used to save energy and cost. The plant produces about an average of 11.42 ton of steam each hour in a year. This steam can be returned or fully recovered (100%) as condensate from the law of conservation of mass since only energy is lost from the steam. But the plant returns a maximum of about 3ton of condensate each hour. This amount is relatively low compared to the amount of condensate recovery possibility. Recovery possibility of condensate return showed that the plant at Sandarne can return at least 8.5 ton of condensate  each hour. In comparison with the current return estimated 5.5 ton of condensate is being lost simply as waste each hour leading to about 400 SEK minimum cost loss. The calculation of cost is in minimum because the charge from water supply and condensate effluent disposal charge are not considered. In this paper only recovery from the easily recoverable steam condensate is being considered (25% of the system) which resulted in payback time of the proposed investment 1.88 years without considering the above explained charges. It is much motivating study considering the generalized approach and over simplified method. If a deeper investigation is made on the potential, it can be clearly shown that how significant the potential is in securing and sustaining energy and environmental issues. Ensuring the security and sustainability of energy which addresses the environmental issue precisely will help the plant to stay on the race of global market competition.   Keywords: Energy efficiency, Boiler efficiency, Energy management, Condensate recovery,

Energy is a critical resource in all types of computing systems from servers, where energy costs dominate data centre expenses and carbon footprints, to embedded systems, where the system's battery life limits the device's functionality. In their efforts to reduce the energy use of these system's hardware manufacturers have implemented features which allow a reduced energy consumption under software control. This thesis shows that managing these settings is a more complex problem than previously considered. Where much (but not all) of the previous academic research investigates unrealistic scenarios, this thesis presents a solution to managing the power on varying hardware. Instead of making unrealistic assumptions, we extract a model from empirical data and characterise that model. Our models estimate the effect of different power management settings on the behaviour of the hardware platform, taking into account the workload, platform and environmental characteristics, but without any kind of a-priori knowledge of the specific workloads being run. These models encapsulate a system's knowledge of the platform. We also developed a \emph{generalised energy-delay} policy which allows us to quickly express the instantaneous importance of both performance and energy to the system. It allows us to select a power management strategy from a number of options. This thesis shows, by evaluation on a number of platforms, that our implementation, Koala, can accurately meet energy and performance goals. In some cases, our system saves 26\% of the system-level energy required for a task, while losing only 1\% performance. This is nearly 46\% of the dynamic energy. Taking advantage of all energy-saving opportunities requires detailed platform, workload and environmental information. Given this knowledge, we reach the exciting conclusion that near optimal power management is possible on real operating systems, with real platforms and real workloads.

Lithium-ion based battery energy storage system has become one of the most popular forms of energy storage system for its high charge and discharge efficiency and high energy density. This dissertation proposes a high-efficiency grid-tie lithium-ion battery based energy storage system, which consists of a LiFePO4 battery based energy storage and associated battery management system (BMS), a high-efficiency bidirectional ac-dc converter and the central control unit which controls the operation mode and grid interface of the energy storage system. The BMS estimates the state of charge (SOC) and state of health (SOH) of each battery cell in the pack and applies active charge equalization to balance the charge of all the cells in the pack. The bidirectional ac-dc converter works as the interface between the battery pack and the ac grid, which needs to meet the requirements of bidirectional power flow capability and to ensure high power factor and low THD as well as to regulate the dc side power regulation. A highly efficient dual-buck converter based bidirectional ac-dc converter is proposed. The implemented converter efficiency peaks at 97.8% at 50-kHz switching frequency for both rectifier and inverter modes. To better utilize the dc bus voltage and eliminate the two dc bus bulk capacitors in the conventional dual-buck converter, a novel bidirectional ac-dc converter is proposed by replacing the capacitor leg of the dual-buck converter based single-phase bidirectional ac-dc converter with a half-bridge switch leg. Based on the single-phase bidirectional ac-dc converter topology, three novel three-phase bidirectional ac-dc converter topologies are proposed. In order to control the bidirectional power flow and at the same time stabilize the system in mode transition, an admittance compensator along with a quasi-proportional-resonant (QPR) controller is adopted to allow smooth startup and elimination of the steady-state error over the entire load range. The proposed QPR controller is designed and implemented with a digital controller. The entire system has been simulated in both PSIM and Simulink and verified with hardware experiments. Small transient currents are observed with the power transferred from rectifier mode to inverter mode at peak current point and also from inverter mode to rectifier mode at peak current point. The designed BMS monitors and reports all battery cells parameters in the pack and estimates the SOC of each battery cell by using the Coulomb counting plus an accurate open-circuit voltage model. The SOC information is then used to control the isolated bidirectional dc-dc converter based active cell balancing circuits to mitigate the mismatch among the series connected cells. Using the proposed SOC balancing technique, the entire battery storage system has demonstrated more capacity than the system without SOC balancing.
Ph. D.

Approved for public release; distribution is unlimited
A Forward Operating Base (FOB) is designed to support combat operations in an austere environment, which often lacks pre-existing infrastructure. On-site diesel generators are the primary source of FOB electricity. Traditionally, each generator is connected to its own set of loads and operates independently from other generators. The benefits of transitioning from traditional generator employment to an alternative architecture using an Energy Management System (EMS) were investigated in this thesis. The EMS provides an interface between power sources, loads, and energy storage elements to form a microgrid. Using power electronics and programmable logic, the EMS provides capabilities such as power source selection, power metering, flow control, and peak power management. These capabilities enable more efficient generator utilization by matching real time load demand to the smallest capable power source, reducing overall fuel consumption. The EMS offers redundancy as it can connect any one of multiple power sources to critical loads. A hardware-based laboratory experiment demonstrated the ability to transition from one power source to another while providing uninterrupted current to the load. The results of the experiment validate a Simulink model of the EMS. An example load profile was applied to the model to compare overall fuel consumption between the traditional architecture and EMS-enabled microgrid.

Industrial energy accounts for roughly one-third of total global energy consumption and is expected to continue with a similar share in the foreseeable future, therefore the efficient use of energy and energy saving are important issues for the industrial sectors. Energy Efficiency EE is a crucial factor for energy cost-benefits and waste reduction also environmental management, and can be improved by different approaches. Especially in this study the energy saving through management system will be illustrated. EE is achieved by use of an energy management system which presents various strategies, tools, methods, technologies, and effective measures to face energy saving and consumption issues, that also includes energy audits, monitoring, control and continuous improvement of the system. In particular in this work energy saving through maintenance (corrective and preventive) and operative procedures were addressed. Maintenance operations are fundamental in granting machineries and processes energy saving, given the capability of optimising them thanks to the predictive models. The major challenge of maintenance optimization is to implement a maintenance strategy, which maximizes availability and efficiency of the equipment, controls the rate of equipment deterioration, ensures the safe and environmentally friendly operation, and minimizes the total cost of the operation which means the both production and energy cost. In this work, an energy efficiency analysis model was developed formed by integration of a deterministic and probabilistic model of the system, based on a balance of cost/benefits, to optimize maintenance interventions and operative procedures as the first aim of maximizing energy efficiency. In particular, as an element of novelty with respect to literature models, the maintenance influence has been explicitly modeled and used as an optimization parameter. The decision making model and data analysing were shown through application to a case study in an industrial production process in Bitumtec Ltd. plant, which produces bituminous materials for road paving. The motor-driven equipment accounts for approximately 60% of manufacturing final electricity use worldwide. A major barrier to effective policymaking, and to more global acceptance of the energy efficiency potential in industrial motor systems, is the lack of a transparent methodology for quantifying the magnitude and cost-effectiveness of these energy savings. Therefore the power consumption was analyzed, as an example, for the most critical system (the greater energy consumption system) or the three phases electric motor system (160 kW) “Siefer” which drives the homogenization mill during production. Bottom-up energy efficiency supply curve models is used to estimate the cost-effective electricity efficiency potentials, also CO2 emission reduction, for the motor system. Using a combination of expert opinions and available data, from our selected industrial case study, there was introduced an analysis approach where is used the concept of a “conservation supply curve CSC” to capture the cost effective as well as the technical potential for energy efficiency. The curve shows the energy conservation potential as a function of the marginal Cost of Conserved Energy. This approach is explained in details; further the results were illustrated and discussed. The first step of this study was a literature review to develop a base line of information, through of research in the field of energy management systems, industrial energy efficiency technologies. That included general review of energy saving models, also optimization of energy consumption in industrial production process. Because of the importance of the maintenance activities and reliability of the systems, also was reviewed maintenance optimization models and their impacts on energy cost-effectiveness, productivity benefits and environments. A part of these studies are introduced in this work and illustrated as the theoretical parts. Analysis has been emphasized, the importance of optimizing maintenance activities and operating procedures to increase the performance of the system. Energy efficiency was evaluated for three different base case scenarios; Low, Medium and High with their related potential energy recovery, performance and environmental benefits. Maximizing efficiency of the system that is our goal is achieved through the use of this model, which also based on analysis of historical data, expert inputs and analysis of the economic impacts that was discussed and demonstrated by the results. In this work the proposed framework with flowing steps are introduced: • Identification of the Most Important System MIS Specially, in this study a motor-driven system in a production process of bituminous materials in Bitumtec Ltd. plant, is addressed. • Identification of the most critical component MCC Particularly, in this study is addressed the electrical motor (160 kWh) that drives homogenization mill “Siefer” during production process of bituminous materials. • Life time and energy consumption data collection and observation, also data related to maintenance activities (corrective and preventive) and failures data collection. • Estimated costs of maintenance and the economic evaluation of maintenance policies (based on balanced cost and risk of inefficiency). • Maintenance optimization (in terms of probability and consequences). • Estimated operating costs of the system. • Analysis of energy efficiency through maintenance optimization and operating procedures, by using of bottom-up energy efficiency supply curve analysis model, where it was introduced; Expert inputs (based on the information of the expert of the system), and data assumption. • Definition of three base case scenarios In this case, were defined three efficiency base case scenarios; low, Medium and High, base case levels with related potential for recovery of electricity. Further, was proposed the related efficiency measures o adequate solutions (cost-effective) to increase the efficiency, based on the maintenance activities, operating procedures and the conditions of the system. • Determination of the impact of these measures on the performance.

The density of wireless access nodes keeps increasing to provide ubiquitous wireless access and meet the ever-increasing traffic demand. However, the shrinking distance among neighboring access nodes causes excessive interference and the increasing number of access nodes incurs a higher power consumption. A careful management of interference ensures a high system capacity. An improved energy efficiency in wireless access network prevents the fast growth of wireless communication systems from aggravating the global energy crisis. In this thesis, we propose a novel architecture, Fiber-connected Massively Distributed Antennas (FMDA), to address the challenges of managing interference and improving energy efficiency in wireless access networks. A FMDA system is composed of a centralized processing system connected to a large number of antennas via optical cables. The centralized processing system processes all the radio signals and allocates all the radio resources to better manage interference; each antenna contains much simpler circuits than conventional access nodes and therefore allows a massive deployment and reduces the antenna power consumption. We first propose a novel multi-cell wireless local area network (WLAN) system based on our proposed FMDA architecture, where the centralized processing system can see the entire spectrum usage across the coverage area and control the radio signals to be sent to each antenna, thus allowing a better management of inter-cell interference. We then propose an antenna scheduling scheme in a novel cellular system composed of fiber-connected femto access nodes to manage the excessive inter-femtocell interference and reduce the energies consumed by non-sleeping access nodes, thus simultaneously improving the spectral and energy efficiency. When the number of cooperating antennas increases, the power consumption of signal processing spikes, thus drastically degrading the overall energy efficiency due to much smaller radio transmission power levels. Focusing on two typical indoor environments, office buildings and large public venues, we propose two low-complexity downlink transmission schemes to address these energy efficiency challenges.

It! is! necessary! for! large! companies! to! understand! and! be! able! to! adapt! to! the! industrial! transformation! towards! an! increasing! focus! on! energy! efficiency,! which! takes! place! today.! The!Energy!Efficiency!Directive!(EED)!issued!by!the!European!Union!has!enlarged!the!focus! on! working! with! energy! efficiency! within! large! companies.! Further,! the! Swedish! government! has! introduced! the! law! about! energy! auditing! in! large! companies,! which! is! based! on! the! EED.! These! regulations! encourage! companies! to! develop! a! management! system!that!includes!requirements!on!conducting!energy!audits!and!propose!costDeffective! measures.! ! Energy! efficiency! is! already! an! important! aspect! within! many! companies! environmental! work,! however! a! more! developed! and! systematic! approach! to! energy! efficiency! than! most! companies! already! have! is! needed! in! order! to! fulfill! the! legal! requirements.! The! Company! investigated! in! this! study! is! one! the! worlds! leading! technology! companies! with! more! than! 9000! employees! in! Sweden.! Currently,! they! have! energy! as! a! significant! aspect! in! their! environmental! work! according! to! the! international! management! system! standard! ISO! 14001.! Today! they! are! also! developing! their! energy! work! by! conducting! energy! audits! in! order!to!comply!with!the!new!legislation.!This!gives!a!more!detailed!view!of!the!energy!use! and! potential! improvements! that! can! be! done,! but! in! order! to! ensure! continual! improvements!over!a!long!period!of!time!further!measures!are!needed.!! ! Within! this! study! it! was! investigated! what! measures! a! large! company! needs! to! implement! in! order! to! increase! their! energy! performance! and! comply! with! the! legislation.! By! a! literature! review! focusing! on! management! systems! as! well! as! interviews! within! the! Company,! a! complementary! study! with! two! companies! covered! by! the! EED! and! three! expert! interviews,! five! key! factors! were! identified.! These! factors! are;! top! management! commitment,! awareness,! goals,! measurements! and! evaluation.! A! model! was! then! developed! aligning! these! factors.! Further,! concrete! proposals! for! action! to! manage! these! factors! were! presented.! By! increasing! focus! on! these! key! factors! and! implement! proposed! measures! companies! will! increase! their! energy! performance! and! also! make! the! organization!aware!of!how!actions!affect!a!company’s!energy!performance.!

Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2015̆.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 71-72).
Exploring a systems-based view of the energy efficiency roadblocks faced by financiers, builders, owners, and tenants. In 1992 Amory Lovins, founder of the Rocky Mountain Institute, wrote a paper entitled "Energy-Efficient Buildings: Institutional Barriers and Opportunities". In it, he detailed roadblocks to constructing energy efficient commercial buildings- from the fear of lenders to finance the unknown, to developers unmotivated to instill efficiency, to mechanical engineers specifying job-securing (and commission-increasing) safety margins when (over)sizing the apparati- every step of a commercial building's genesis is fraught with status quo and timidity. Now, almost 25 years later, we will take a look at what has changed, what hasn't, and what areas still need incentivizing to get on a sustainable track towards efficiency. We model the systems to exhibit the persistent resistance to changes, the extraordinary pace with which some markets have embraced change, and the feedback mechanisms that can make efficiency both possible and profitable.
by James G. Franklin.
S.M. in Engineering and Management

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 63-65).
Green HPC is the new standard for High Performance Computing (HPC). This has now become the primary interest among HPC researchers because of a renewed emphasis on Total Cost of Ownership (TCO) and the pursuit of higher performance. Quite simply, the cost of operating modern HPC equipment can rapidly outstrip the cost of acquisition. This phenomenon is recent and can be traced to the inadequacies in modern CPU and Datacenter systems design. This thesis analyzes the problem in its entirety and describe best practice fixes to solve the problems of energy-inefficient HPC.
by Kurt Keville.
S.M.in Engineering and Management

The great innovations of the last century have ushered continuous progress in many areas of technology, especially in the form of miniaturization of electronic circuits. This progress shows a trend towards consistent decreases in power requirements due to miniaturization. According to the ITRS and industry leaders, such as Intel, the challenge of managing and providing power efficiency still persist as scaling down of devices continues. A variety of power sources can be used in order to provide power to low power applications. Few of these sources have favorable characteristics and can be designed to deliver maximum power such as the novel mini notched turbine used as a source in this work. The MiNT is a novel device that can be used as a feasible energy source when integrated into a system and evaluated for power delivery as investigated in this work. As part of this system, a maximum power point tracking system provides an applicable solution for capturing enhanced power delivery for an energy harvesting system. However, power efficiency and physical size are adversely affected by the characteristics and environment of many energy harvesting systems and must also be addressed. To address these issues, an analysis of mini notched turbine, a RF rectenna, and an enhanced maximum power point tracking system is presented and verified using simulations and measurements. Furthermore, mini notched energy harvesting system, RF rectenna energy harvesting system, and enhanced maximum power point tracking system are developed and experimental data analyzed. The enhanced maximum power point tracking system uses a resistor emulation technique and particle swarm optimization (PSO) to improve the power efficiency and reduce the physical size. This new innovative design improves the efficiency of optimized power management circuitry up to 7% compared to conventional power management circuits over a wide range of input power and range of emulated resistances, allowing more power to be harvested from small energy harvesting sources and delivering it to the load such as smart sensors. In addition, this is the first IC design to be implemented and tested for the patented mini notched turbine (MiNT) energy harvesting device. Another advantage of the enhanced power management system designed in this work is that the proposed approach can be utilized for extremely small energy sources and because of that the proposed work is valid for low emulated resistances. and systems with low load resistance Overall, through the successful completion of this work, various energy harvesting systems can have the ability to provide enhanced power management as the IC industry continues to progress toward miniaturization of devices and systems.

Nowadays, the increasing of the energy consumption is producing serious changes in the natural environment as the global warming. Around the 40% of all greenhouse gas emissions in developed countries come from the building equipments, where approximately 60% are produced by the air conditioning systems. In this context, ground coupled heat pumps are an attractive solution as air conditioning systems in commercial buildings due to their higher efficiency compared with the conventional air to water heat pump. In fact, the American Environmental Protection Agency recognizes ground coupled heat pump systems among the most efficient and comfortable systems available today. Nevertheless, the energy efficiency of the ground coupled heat pumps could be improve by means a properly management of the di erent equipments which form them. The objective of the research of this PhD thesis will be the development of management strategies in the air conditioning system based on the ground coupled heat pumps to improve its energy efficiency at the same time that we keep the thermal comfort in the conditioned areas. The energy management strategies will be oriented in the three ways: combining of several generation systems (ground coupled heat pump and air to water heat pump), decoupling thermal generation from thermal distribution (by means a thermal storage device) and strategies based on the management of the devices of the system (by means of continuous regulation of them). From the results of this research we can obtain two main conclusions. The rst one is that a properly management of a system composed by a thermal storage, an air to water heat pump and a ground coupled heat pump produce an improvement of the energy efficiency around a 40% respect to a conventional system and around a 18% respect to a geothermal system. The second main conclusion of this thesis is that a properly management strategy in continuous regulation of the devices which are part of a ground coupled ..
Pardo García, N. (2009). Energy efficiency improvement of hybrid ground coupled HVAC systems from thermal energy generation and storage management [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6065
Palancia

Global warming imposes great challenges, and anthropogenic greenhouse gas emissions have to be reduced by active measures. The transportation sector is one of the key sectors where significant reductions are desired. Within a vehicle, the cooling/thermal management system is a subsystem intended for temperature control of automotive components. Reducing the power consumption for thermal management is one of several possible ways to reduce the environmental impact of the vehicle. This report considers an existing reference cooling system, with three separate circuits at different temperature levels. The purpose is to suggest improvements to the reference system with respect to increasing energy efficiency as well as reducing the number of components. Potential improvements are identified during a literature study, and then evaluated one by one. After the first evaluation, four improvements are selected: Firstly, a liquid-to-liquid heat exchanger in high temperature circuit, with connections to both the medium and low temperature circuits. Secondly, common medium/low temperature radiators, which can be allocated according to cooling demand. Thirdly, pipe connections for coolant transfer between the low and medium temperature circuits. Finally, a liquid-cooled condenser in the active cooling system, cooled by the medium temperature circuit. The result is a system with flexible radiator allocation, more even load distribution, ability to heat components using heat losses from other components, and one radiator less than the reference system. A complete system evaluation is performed in order to find the most beneficial arrangement of the components. Steady state calculations are performed in MATLAB, using five different operational cases as input data. Out of six different alternatives, one is recommended for high load operation and another for low load operation. The difference between the two is the position of the condenser, since a low condensation temperature should be prioritized at part load but not at high load. The main uncertainties of this report are steady state calculations, which are not fully reflecting real driving situations, and approximations due to lack of input data. For further work, verification of these results by transient simulations and practical testing is recommended. Removing one of the high temperature radiators could be investigated, as well as downsizing the medium temperature radiator. Integration with the cabin thermal management system, which is beyond the scope of this report, is also a relevant area for future investigation. By suggesting improvements to an automotive subsystem, this report strives to make a difference on a small-scale level, but also to contribute to an ongoing transition process on the global level.
Den globala uppvärmningen medför stora utmaningar, och de antropogena växthusgasutsläppen måste minskas genom aktiva åtgärder. Transportsektorn är en av de viktigaste sektorerna där avsevärda utsläppsminskningar eftersträvas. I ett fordon är kylsystemet ett delsystem avsett att kontrollera temperaturen på komponenter som är viktiga för fordonets funktion. Att sänka kylsystemets effektförbrukning är ett av flera möjliga sätt att minska fordonets miljöpåverkan. Den här rapporten utgår från ett befintligt referenskylsystem, med tre separata kretsar som arbetar vid olika temperaturnivåer. Syftet är att föreslå förbättringar för att öka energieffektiviteten, samt minska antalet komponenter i systemet. Potentiella förbättringar identifieras genom en litteraturstudie, och utvärderas därefter en efter en. Efter denna utvärdering väljs fyra förbättringar ut: För det första, en vätskevärmeväxlare i högtemperaturkretsen, med anslutningar till både mellan- och lågtemperaturkretsen. För det andra, gemensamma mellan- och lågtemperaturkylare, som kan fördelas mellan kretsarna efter behov. För det tredje, röranslutningar för överföring av kylvätska mellan låg- och mellantemperaturkretsen. Slutligen, en vätskekyld kondensor i det aktiva kylsystemet, vilken kyls av mellantemperaturkretsen. Resultatet är ett kylsystem med flexibel tilldelning av kylare, jämnare fördelning av värmeförluster, möjlighet att värma komponenter med förlustvärme från andra komponenter, samt en kylare mindre än referenssystemet. Som sista steg genomförs en helsystemsutvärdering, för att hitta det mest fördelaktiga sättet att placera komponenterna i förhållande till varandra. Stationära beräkningar utförs i MATLAB, med fem olika driftfall som indata. Av sex olika utformningar rekommenderas en för drift med hög belastning, och en annan för drift med lägre belastning. Skillnaden mellan dem är kondensorns placering, på grund av att en låg kondensationstemperatur bör prioriteras vid låg belastning men inte vid hög belastning. Den största osäkerheten i tillvägagångssättet är de stationära beräkningarna, som inte helt motsvarar verkliga körfall, samt approximationer som gjorts vid brist på indata. För framtida arbete rekommenderas verifiering av dessa resultat genom transienta simuleringar och praktiska tester. Att ta bort en av högtemperaturkylarna och/eller minska storleken på mellantemperaturkylaren kan också undersökas. Även integration med kupéns värme- och kylsystem, vilket ligger utanför ramen för denna rapport, är ett relevant område för fortsatta undersökningar. Genom att föreslå förbättringar av ett delsystem i ett fordon strävar denna rapport efter att åstadkomma förbättringar på liten skala, men också att bidra till en pågående omvandling på den globala skalan.

Det är nödvändigt för stora företag att förstå och kunna anpassa sig till den industriella omvandling mot ett ökat fokus på energieffektivitet som sker idag. Energieffektiviseringsdirektivet som Europeiska Unionen har utfärdat har ökat fokus på att arbeta med energieffektivitet i stora företag. Vidare har den svenska regeringen infört lagen om energikartläggning i stora företag som är baserad på Energieffektiviseringsdirektivet. Dessa lagstadgade krav uppmuntrar företag att utveckla ett ledningssystem som ställer krav på genomförande av energikartläggningar samt föreslå kostnadseffektiva åtgärder. Energieffektivitet är redan en riktigdel i många företags miljöarbete dock krävs ett mer Utvecklat och systematiskt arbetssätt än det många företag redan har för att uppnå kraven i Energieffektiviseringsdirektivet och den svenska lagen. Företaget som har undersökts i denna studie är ett världsledande teknikföretag med mer än 9000 anställda i Sverige. För närvarande har de energi som en signifikant aspekt i sitt miljöarbete i enlighet med den internationella standarden för miljöledningssystem ISO14001dag utvecklar de även sitt energiarbete genom att utföra energikartläggningar för att uppfylla den nya lagstiftningen. Detta ger en mer detaljerad insikt över energianvändningen och möjliga förbättringar som kan göras, men för att säkerställa ständiga förbättringar över en längre tidsperiod krävs ytterligare åtgärder.  I den här studien har det undersökts vilka åtgärder som ett stort företag måste införa för att öka energiprestandan och följa lagstiftningen. Genom en litteraturstudie som fokuserade på ledningssystem i kombination med intervjuer på det undersöka företaget, en kompletterande studie av två företag som omfattas av direktivet samt tre expertintervjuer identifierades fem nyckelfaktorer. Dessa faktorer är högsta ledningens engagemang, medvetenhet, mål, mätningar och utvärdering. En modell för att strukturera faktorerna utvecklades sedan. Vidare presenterades konkreta förslag på hur dessa faktorer ska implementeras. Genom att öka fokus på dessa nyckelfaktorer och implementera föreslagna åtgärder kommer företag öka sin energiprestanda och medvetenhet i organisationen om hur olika handlingar påverkar företagets energiprestanda.
It is necessary for large companies to understand and be able to adapt to the industrial Transformation towards an increasing focus on energy efficiency, which takes place today. The Energy Efficiency Directive (EED)issued by the European Union has enlarged the focus on working with energy efficiency within large companies. Further, the Swedish government has introduced the law about energy auditing in large companies, which is based on the EED. These regulations encourage companies to develop a management system that includes requirements on conducting energy audits and propose cost Deffective measures. Energy efficiency is already an important aspect within many companies environmental work, however a more developed and systematic approach to energy efficiency than most companies already have is needed in order to fulfill the legal requirements. The Company investigated in this study is one the worlds leading technology companies with more than 9000  employees in Sweden. Currently, they have energy as a significant aspect in their environmental work according to the international management system standard ISO 14001. Today they are also developing their energy work by conducting energy audits in order to comply with the new legislation. This gives a mor detailed view of the energy use and potential improvements that can be done, but in order to ensure continual improvements over a long period of time further measures are needed. Within this study it was investigated what measures a large company needs to implement in order to increase their energy performance and comply with the legislation. By a literature review focusing on management systems as well as interviews within the Company, a complementary study with two companies covered by the EED and three expert  interviews, five key factors were identified. These factors are, top management commitment, awareness, goals, measurements and evaluation. A model was then developed aligning these factors. Further, concrete proposals for action to manage these factors were presented. By!increasing focus on these key factors and implement proposed measures companies will increase their energy performance and also make the organization aware of how actions affect a company’s energy performance

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; in conjunction with the Leaders for Global Operations Program at MIT, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 75-76).
Energy management in industrial facilities is becoming increasingly popular as firms attempt to become more environmentally responsible and reduce cost by improving operational efficiency. Raytheon is a leader in their industry in energy management, and they view the initiative as a way to become more competitive along with being environmentally responsible. The goal of this project was to develop a framework for achieving sustainable cost reduction in production operations through energy efficiency. The energy efficiency framework will build off the existing lean and six sigma tools and philosophies in an attempt to accelerate acceptance and deployment by using a common language and proven methods in the company and industry. A 1.6 million square foot manufacturing facility at Raytheon IDS consumed $13 million of energy (90% electric) in 2010, 75% of which was consumed directly by production equipment. The equipment is diffuse, highly specialized, and used in "high mix, low volume" manufacturing. The challenge with improving production energy efficiency in this environment is that it requires a combination of technology improvements, processes modifications, and changes in the way employees conduct their work every day. The project's success relied on cross-functional (i.e., operations, engineering, and facilities) engagement from senior management to front-line operators. To sustain results, energy performance metrics were designed to keep production area leaders engaged and allow management to set progressive goals over time and reward success. The proposed metrics use a combination of tracked energy use and a "best practice" scorecard that promotes proactive engagement. Lean "Energy Gemba Walks" were initiated to generate and manage best practices and to share knowledge among production areas. The implementation phase of the pilot project (October and November 2011) resulted in an 18% energy reduction compared with the average for the year. Meanwhile, production output and total labor hours were up 18% and 11%, respectively, during the pilot, while the product mix remained constant throughout the year. The improvements, if sustained, correspond to a $74,000 per year cost savings in the pilot area.
by Kurtis McKenney.
S.M.
M.B.A.

Demand Side Management (DSM) is one of the most viable and sustainable short term methods to address the shortfall in electricity generation in South Africa. This is because DSM projects can be implemented relatively quickly and inexpensively when compared with alternative generation options. This specifically applies to the mining industry. South African mines presently consume 15% of Eskom-generated electricity. Mine compressed air systems are some of the biggest users, consuming approximately 21% of mine electricity consumption. Electricity savings on compressed air systems are therefore important. With this study, various Energy Efficiency methods on compressed air systems were investigated. These methods include variable speed drives on compressor motors, temperature control of compressor discharge, minimising pressure drops in the air distribution systems, eliminating compressed air leaks, and optimising compressor selection and control. The most efficient strategies were identified, taking into account factors such as financial viability, sustainability, and ease of implementation. The best strategies were found to be the optimised control and selection of compressors, minimising compressed air leaks, and the optimal control of system pressure. These strategies were implemented and tested on large compressed air systems in gold and platinum mines. Savings of between 10% and 35% on the maximum demand of the systems were achieved. In present monetary terms this translates to as much as R108 million savings for the mines per year at the end of 2009 tariffs. If total mine compressed air electricity consumption can reduce by 30%, it will result in nearly a 1% reduction in total Eskom demand. This shows that mine compressed air savings can make a significant contribution to the drive for Energy Efficiency in South Africa.
Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2010.

In recent years, the energy shortage has become a barrier to social development as there is a shortage of resources, especially non-renewable resources. In order to improve the current situation of human settlement for future generations, a series of environmental protection activities and rational utilizations of natural resources have been carried out at a global level on the theme of "Sustainable Development". Along with the quantitative growth of Chinese public buildings, especially the Large-Scale Public Buildings, the levels of energy consumption are rising and this phenomenon has been seen as a key point of energy management from a national view. This paper discusses the realities of energy consumption and the energy-saving policies of public buildings in the world’s major developed countries, and sums up the current condition of Chinese energy consumption in relation to public buildings. With regard to these factors, this paper tries to find approaches for solving the existing problems in each construction section. Less developed construction technology in China leads to a waste of materials and labor force. There is a lack of professional personnel to handle the operational management and a lack of consideration for energy efficiency in the designing process. There is not a suitable framework for compiling statistics and data on energy consumption. There are still many management problems such as inadequate policy standards in operability or implementation, unclear positioning in governmental management, ineffective incentive or punitive mechanisms, and a defective state system which results directly in an undeveloped service system for energy efficiency. Based on all of the problems listed above, this paper suggests solutions in four areas, namely Policy, Energy Statistics, Management and Education, in order to give academic support for the overhaul of Large-Scale Public Buildings towards greater energy efficiency in China.

Data centers are computing infrastructure facilities that house arrays of electronic racks containing high power dissipation data processing and storage equipment whose temperature must be maintained within allowable limits. In this research, the sustainable and reliable operations of the electronic equipment in data centers are shown to be possible through the Open Engineering Systems paradigm. A design approach is developed to bring adaptability and robustness, two main features of open systems, in multi-scale convective systems such as data centers. The presented approach is centered on the integration of three constructs: a) Proper Orthogonal Decomposition (POD) based multi-scale modeling, b) compromise Decision Support Problem (cDSP), and c) robust design to overcome the challenges in thermal-fluid modeling, having multiple objectives, and inherent variability management, respectively. Two new POD based reduced order thermal modeling methods are presented to simulate multi-parameter dependent temperature field in multi-scale thermal/fluid systems such as data centers. The methods are verified to achieve an adaptable, robust, and energy efficient thermal design of an air-cooled data center cell with an annual increase in the power consumption for the next ten years. Also, a simpler reduced order modeling approach centered on POD technique with modal coefficient interpolation is validated against experimental measurements in an operational data center facility.

Les plates-formes multi/multi-cœurs organisées en clusters représentent des solutions prometteuses pour fournir des performances de calcul élevées et une efficacité énergétique optimisée dans les systèmes embarqués modernes. Ces plates-formes prennent souvent en charge la gestion dynamique tension/fréquence (DVFS) par cluster, ce qui permet à différents clusters de modifier leurs propres niveaux tension/ fréquence indépendamment. La complexité et le dynamisme croissants des applications sur ces plates-formes rendent nécessaire la gestion en ligne des ressources. Ce mémoire se concentre sur les méthodes de gestion en ligne des applications sur des systèmes multi/multi-cœurs en cluster pour améliorer l'efficacité énergétique. Cette thèse présente différentes stratégies de gestion qui permettent d'estimer l'influence mutuelle entre l'allocation des applications et la configuration en tension/fréquence des clusters afin d'obtenir respectivement une optimisation locale au sein d'un cluster et une optimisation globale dans l'ensemble du système. Les stratégies proposées permettent d'obtenir des solutions de gestion optimisées avec moins de complexité que les stratégies existantes. De plus, cette thèse présente une nouvelle approche de modélisation et de simulation qui permet d'évaluer les stratégies de gestion en ligne dans les systèmes multi/multi-cœurs pour garantir que les contraintes du système sont pleinement respectées. L'approche de simulation proposée est validée à l'aide d'un cadre de modélisation et de simulation industrielle
Cluster-based multi/many-core platforms represent promising solutions to deliver high computing performance and energy efficiency in modern embedded systems. These platforms often support per-cluster Dynamic Voltage/Frequency Scaling (DVFS), allowing different clusters to change their own v/f levels independently. The increasing application complexity and application dynamism on such platforms arise the need for run-time management. This dissertation focuses on the run-time management of applications on clusterbased multi/many-core systems to improve energy efficiency. Towards the run-time management purpose, this dissertation presents different management strategies that estimate the mutual influence between application mapping and cluster v/f configurations to respectively achieve local optimization within a cluster and global optimization in the overall system. The proposed management strategies can achieve near-optimal management solutions with less strategy complexity compared to state-of-theart strategies. ln addition, this dissertation presents a new modelling and simulation approach that allows the evaluation of run-time management strategies in multi/many-core systems to guarantee that system constraints are fully met. The proposed simulation approach is validated using an industrial modelling and simulation framework

Extraordinary improvements in computing performance, density, and capacity have driven rapid increases in system energy consumption, motivating the need for energy-efficient performance. Harnessing the collective computational capacity of thousands of these systems can consume megawatts of electrical power, even though many systems may be underutilized for extended periods of time. At scale, powering and cooling unused or lightly loaded systems can waste millions of dollars annually. To combat this inefficiency, we propose system software, control systems, and architectural techniques to improve the energy efficiency of high-capacity memory systems while preserving performance. We introduce and discuss several new application-transparent, memory management algorithms as well as a formal analytical model of a power-state control system rooted in classical control theory we developed to proportionally scale memory capacity with application demand. We present a prototype implementation of this control-theoretic runtime system that we evaluate on sequential memory systems. We also present and discuss why the traditional performance-motivated approach of maximizing interleaving within memory systems is problematic and should be revisited in terms of power and thermal efficiency. We then present power-aware control techniques for improving the energy efficiency of symmetrically interleaved memory systems. Given the limitations of traditional interleaved memory configurations, we propose and evaluate unorthodox, asymmetrically interleaved memory configurations. We show that when coupled with our control techniques, significant energy savings can be achieved without sacrificing application performance or memory bandwidth.
Ph. D.

Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Schwan, Karsten; Committee Co-Chair: Yalamanchili, Sudha; Committee Member: Lee, Hsien-Hsin Sean; Committee Member: Loh, Gabriel; Committee Member: Madisetti, Vijay; Committee Member: Owen, Henry

Unreliable and unsustainable electricity supply has been experienced in South Africa since 2007. Eskom implemented Demand Side Management (DSM) as a short-term solution to alleviate this problem. Several compressed-air DSM projects were implemented to help reduce the strain on the electrical network. Compressed air is an integral part of production in deep-level mining, and is extensively utilised. Problems are encountered with the effective management and repairing of leaks, since the majority of mines have little to no procedures in place for leak management. Awareness of the condition of the compressed-air system and leaks needed to be created at management level in order to achieve the best results. The purpose of this study is to investigate the effect of proper leak management on compressed-air systems in the mining industry. Peak-clipping DSM projects implemented in the mining industry were used for evaluation of results. Contribution to the sustainability of compressed-air DSM projects savings through successful leak documentation was the prime focus of this study. This was achieved through the development of a Compressed Air Leakage Documentation System (CALDS). This entailed the electronic field-data capture and record keeping of field data, using rugged PDA devices suitable for the extreme environmental conditions encountered in deep-level mining. Report generation on the status of detected leaks created awareness of compressedair- system performance and leak-repair tracking at management level. Audible detection was sufficient for this study, since the focus was on the larger more-severe leaks. Leaks were expressed in monetary terms to indicate the severity. It was found that successful management of leaks could contribute to an increase of as much as 85% in project savings. The results also showed that creating awareness through documentation of leaks, and the effect this has on the system, resulted in regular repairing of these leaks. Sustainability of projects was maintained during an evaluation period of ten months, with projects achieving on average 125% of target savings. The study showed that effective reporting on compressed-air leaks resulted in increased system efficiency and sustainable DSM project savings. It was also seen that leak detection by outsourced companies did not necessarily result in financial savings. When the mine took responsibility for its own leak detection and repairs, significant savings were realised.
Thesis (M.Ing. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2011.

In the United States, over 40% of the country's total energy consumption is in buildings, most of which are either small-sized (<5,000 sqft) or medium-sized (5,000-50,000 sqft). These buildings offer excellent opportunities for energy saving and demand response (DR), but these opportunities are rarely utilized due to lack of effective building energy management systems and automated algorithms that can assist a building to participate in a DR program. Considering the low load factor in US and many other countries, DR can serve as an effective tool to reduce peak demand through demand-side load curtailment. A convenient option for the customer to benefit from a DR program is to use automated DR algorithms within a software that can learn user comfort preferences for the building loads and make automated load curtailment decisions without affecting customer comfort. The objective of this dissertation is to provide such a solution. First, this dissertation contributes to the development of key features of a building energy management open source software platform that enable ease-of-use through plug and play and interoperability of devices in a building, cost-effectiveness through deployment in a low-cost computer, and DR through communication infrastructure between building and utility and among multiple buildings, while ensuring security of the platform. Second, a set of reinforcement learning (RL) based algorithms is proposed for the three main types of loads in a building: heating, ventilation and air conditioning (HVAC) loads, lighting loads and plug loads. In absence of a DR program, these distributed agent-based learning algorithms are designed to learn the user comfort ranges through explorative interaction with the environment and accumulating user feedback, and then operate through policies that favor maximum user benefit in terms of saving energy while ensuring comfort. Third, two sets of DR algorithms are proposed for an incentive-based DR program in a building. A user-defined priority based DR algorithm with smart thermostat control and utilization of distributed energy resources (DER) is proposed for residential buildings. For commercial buildings, a learning-based algorithm is proposed that utilizes the learning from the RL algorithms to use a pre-cooling/pre-heating based load reduction method for HVAC loads and a mixed integer linear programming (MILP) based optimization method for other loads to dynamically maintain total building demand below a demand limit set by the utility during a DR event, while minimizing total user discomfort. A user defined priority based DR algorithm is also proposed for multiple buildings in a community so that they can participate in realizing combined DR objectives. The software solution proposed in this dissertation is expected to encourage increased participation of smaller and medium-sized buildings in demand response and energy saving activities. This will help in alleviating power system stress conditions by employing the untapped DR potential in such buildings.
Ph. D.

In recent years, the energy shortage has become a barrier to social development as there is a shortage of resources, especially non-renewable resources. In order to improve the current situation of human settlement for future generations, a series of environmental protection activities and rational utilizations of natural resources have been carried out at a global level on the theme of "Sustainable Development". Along with the quantitative growth of Chinese public buildings, especially the Large-Scale Public Buildings, the levels of energy consumption are rising and this phenomenon has been seen as a key point of energy management from a national view. This paper discusses the realities of energy consumption and the energy-saving policies of public buildings in the world’s major developed countries, and sums up the current condition of Chinese energy consumption in relation to public buildings. With regard to these factors, this paper tries to find approaches for solving the existing problems in each construction section. Less developed construction technology in China leads to a waste of materials and labor force. There is a lack of professional personnel to handle the operational management and a lack of consideration for energy efficiency in the designing process. There is not a suitable framework for compiling statistics and data on energy consumption. There are still many management problems such as inadequate policy standards in operability or implementation, unclear positioning in governmental management, ineffective incentive or punitive mechanisms, and a defective state system which results directly in an undeveloped service system for energy efficiency. Based on all of the problems listed above, this paper suggests solutions in four areas, namely Policy, Energy Statistics, Management and Education, in order to give academic support for the overhaul of Large-Scale Public Buildings towards greater energy efficiency in China.
www.ima.kth.se

Today, issues such as climate change and increased competition for scarce resources puts pressure on society and firms to transform. Change is not easily managed though, especially not when relating to production or consumption of energy carriers such as district heating or electric power. These systems do not only have strong dynamics internally, but dynamics between multiple technological systems must sometimes be considered to effectively manage response and strategies in relation to change. During the early 1980s, an optimisation model founded on an expert-based approach was developed based on the partial equilibrium model to enable the evaluation of different actions to reach a target. This model — often referred to as marginal abatement cost curve (MACC) or conservation supply curve (CSC) — is used by academia, industry and policymakers globally. The model is applied for causes such as energy conservation and waste management, but also within the climate change context for optimising CO2 reductions and governmental policy. In this context, the model is used by actors such as the Intergovernmental Panel on Climate Change (IPCC), International Energy Agency (IEA) and World Bank, and by the consultancy firm McKinsey & Company, who use it extensively in different analysis. This model has many drawbacks in relation to managing interdependencies between different options, but more specifically the metric used for ranking options with a negative marginal cost has a design flaw leading to biased results. As a solution Pareto optimisation has been suggested, but is problematic given the dynamics within and between energy systems. The purpose of this compilation dissertation is to improve the ability for industry and policymakers to effectively manage change and reach set targets. In particular it develops our knowledge of how to account for option interdependency within and between technological systems. Furthermore, the ranking problem relating to expert-based least cost integrated planning is addressed. This dissertation also provides policy and managerial implications relating to the issues of energy conservation, CO2 abatement, and SOx and NOx reduction in relation to the district heating system in Stockholm. Implications are also provided for the interaction with other systems such as the Nordic electric power system.
Klimatfrågan och konkurrens om knappa resurser medför ett förändringstryck på nationer och företag. Att hantera förändringar har aldrig varit enkelt, vilket är tydligt bland företag inom energisektorn såsom el och fjärrvärmeproducenter. Energisystemen dessa företag är del av har stark intern dynamik, men även dynamik mellan olika energisystem är vanligt. Detta måste tas i beaktande när strategier och planer för att hantera förändring utformas. Under början av 1980-talet skapades en optimeringsmodell baserad på den nationalekonomiska jämviktsmodellen för att kunna utvärdera olika specifika möjligheter att nå ett mål, t.ex. energibesparingar. Denna modell, som idag ofta benämns MACC (Marginal Abatement Cost Curves) eller CSC (Concervation Supply Curves), används idag av akademin, industrin och myndigheter inom områden så som energibesparingar, minskade CO2-utsläpp, sophantering och design av ekonomiska policyinstrument. De icke-akademiska användarna inkluderar FNs klimatorgan IPCC, IEA och Världsbanken. Även konsultfirman McKinsey&Company använder modellen regelbundet i olika studier. Tyvärr har modellen många begräsningar när det kommer till att hantera dynamiker mellan de specifika åtgärder som identifierats för att nå ett mål. Den allvarligast begränsningen utgörs dock av ett optimeringsfel som leder till felaktiga slutsatser om prioriteringen mellan de åtgärder som har en negativ marginalkostnad. Som en lösning på detta problem har pareto-optimering föreslagits, vilket denna avhandling dock visar är problematiskt på grund av de dynamiker som finns inom och mellan energisystem. Det övergripande syftet med denna avhandling är att förbättra möjligheten att hantera förändringar och nå uppsatta mål. Specifikt diskuteras hur beroenden mellan olika åtgärder för att nå det satta målet kan hanteras. Avhandlingen adresser även problemet att prioritera mellan åtgärder med negativ marginalkostnad. Utöver detta bidrar avhandlingen med praktiska implikationer för politiker, myndigheter och företag involverade i fjärrvärmeproduktion i Stockholm. Slutsatser dras kring energibesparingar och minskade utsläpp av CO2, SOx och NOx. Praktiska implikationer ges även för hur system som detta fjärrvärmesystem samverkar och interagerar med det nordiska elsystemet.

QC 20150414

Investments in energy efficiency and climate change abatement: revising marginal cost curves as an optimization model

Technological advancements in computer hardware and software have made embedded systems highly affordable and widely used. Consumers have ever increasing demands for powerful embedded devices such as cell phones, PDAs and media players. Such complex and feature-rich embedded devices are strictly limited by their battery life- time. Embedded systems typically are diskless and use flash for secondary storage due to their low power, persistent storage and small form factor needs. The energy efficiency of a processor and flash in an embedded system heavily depends on the choice of file system in use. To address this problem, it is necessary to provide sys- tem developers with energy profiles of file system activities and energy efficient file systems. In the first part of the thesis, a macro-model for the CRAMFS file system is established which characterizes the processor and flash energy consumption due to file system calls. This macro-model allows a system developer to estimate the energy consumed by CRAMFS without using an actual power setup. The second part of the thesis examines the effects of using non-volatile memory as a write-behind buffer to improve the energy efficiency of JFFS2. Experimental results show that a 4KB write-behind buffer significantly reduces energy consumption by up to 2-3 times for consecutive small writes. In addition, the write-behind buffer conserves flash space since transient data may never be written to flash.

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。

The ISO 50001 standard on energy management systems was released in 2011 with the aim of providing organizations with a standardised guideline for the evaluation and continual improvement of energy performance. Complex structures such as the waste to energy (WTE) sector, which must comply with social, environmental, economic and productivity objectives, can benefit from the development of a compliant energy management system (EnMS). Energy efficiency and energy savings contribute to the mitigation of the heavy cost of such a facility, while the benchmark analysis allows verifying the state of the system and the potential areas for improvement. The energy performance improvements can be valorised on an environmental base, and proper promotion of the process can contribute to the mitigation of social opposition. This thesis reviews the energy performance of a waste to energy facility located in Lecco, Italy, using the information available from the control system already installed in the company. Regression analysis is used to fit linear and polynomial functional forms to the energy consumption data and create the energy baseline for the areas of significant energy use and production with a predictive power of 59 – 92%. The difference among the baseline and the actual energy consumption is proposed as energy performance indicator, in order to appreciate the results of the improvement opportunities, and a set of key performance indicators are evaluated for internal and external benchmarking of the facility. The economic feasibility of a selection of sectorial Best Available Technologies (BATs) and the related energy performance improvement is evaluated, revealing that 2 – 16 M€ can be invested in the system retrofit; the creation of synergies with the facility heating, cooling and electricity demand is also suggested. Lastly, an energy, economic and environmental analysis is suggested as a ranking system for the identified improvement opportunities. The methodology and results of this study are intended to provide a proper energy review for Silea Spa, suggest a review procedure for other WTE facilities willing to develop a compliant EnMS and enrich the literature with a case study on WTE. For the Italian context, which is currently facing difficulties in the modernization of the waste management system (WMS), the ISO 50001 application on WTE facilities offers a unified structure that can be used by the government to map the current status of each facility and develop the legislative framework in accordance to the needs of the WMS, the circular economy and the public opinion.
ISO 50001-standarden för energihanteringssystem släpptes 2011 för att ge organisationer en standardiserad riktlinje för utvärdering och kontinuerlig förbättring av energiprestanda. Komplexa strukturer som sektorn för avfall till energi (WTE), som måste uppfylla målen socialt, miljömässigt, ekonomiskt och produktivt, kan dra nytta av utvecklingen av ett kompatibelt energihanteringssystem (EnMS). Energieffektivitet och energibesparingar bidrar till att mildra den stora kostnaden för en sådan anläggning, medan jämförelseanalysen gör det möjligt att verifiera systemets tillstånd och de potentiella förbättringsområdena. Förbättringen av energiprestanda kan värderas på en miljöbas, och en korrekt främjande av processen kan bidra till att mildra social opposition. Denna avhandling granskar energiprestanda för ett slöseri till en energianläggning i Lecco, Italien, med hjälp av den information som finns tillgänglig från det styrsystem som redan är installerat i företaget. Regressionsanalys används för att passa linjära och polynomiska funktionsformer till energiförbrukningsdata och skapa energigrundnivå för områdena med betydande energianvändning och produktion med en prediktiv effekt på 59-92%. Skillnaden mellan baslinjen och den faktiska energiförbrukningen föreslås som indikator för energiprestanda för att uppskatta resultaten av förbättringsmöjligheterna och en uppsättning nyckelresultatindikatorer utvärderas för intern och extern riktmärkning av anläggningen. Den ekonomiska möjligheten för ett urval av sektorns bästa tillgängliga teknik (BAT) och den därmed sammanhängande förbättringen av energieffektiviteten utvärderas, vilket visar att 2 - 16 miljoner euro kan investeras i systemets eftermontering. skapandet av synergier med anläggningens uppvärmning, kylning och el efterfrågan föreslås också. Slutligen föreslås en energi-, ekonomisk och miljöanalys som ett rankningssystem för de identifierade förbättringsmöjligheterna. Metoden och resultaten av denna studie är avsedda att ge en ordentlig energianalyse för Silea Spa, föreslå ett granskningsförfarande för andra WTE-anläggningar som är villiga att utveckla en kompatibel ENMS och berika litteraturen med en fallstudie om WTE. För det italienska sammanhanget, som för närvarande står inför svårigheter i moderniseringen av avfallshanteringssystemet (WMS), erbjuder ISO 50001-tillämpningen på WTE-anläggningar en enhetlig struktur som kan användas av regeringen för att kartlägga nuvarande status för varje anläggning och utveckla den rättsliga ramen i enlighet med WMS, den cirkulära ekonomins och den allmänna opinionens behov.

The large difference between processor CPU cycle time and memory access time, often referred to as the memory wall, severely limits the performance of streaming applications. Some data centers have shown servers being idle three out of four clocks. High performance instruction sequenced systems are not energy efficient. The execute stage of even simple pipeline processors only use 9% of the pipeline's total energy. A hybrid dataflow system within a memory module is shown to have 7.2 times the performance with 368 times better energy efficiency than an Intel Xeon server processor on the analyzed benchmarks. The dataflow implementation exploits the inherent parallelism and pipelining of the application to improve performance without the overhead functions of caching, instruction fetch, instruction decode, instruction scheduling, reorder buffers, and speculative execution used by high performance out-of-order processors. Coarse grain reconfigurable logic in an energy efficient silicon process provides flexibility to implement multiple algorithms in a low energy solution. Integrating the logic within a 3D stacked memory module provides lower latency and higher bandwidth access to memory while operating independently from the host system processor.

Battery storage devices have been widely utilized for different applications. However, for high power applications, battery storage systems come with several challenges, such as the thermal issue, low power density, low life span and high cost. Compared with batteries, supercapacitors have a lower energy density but their power density is very high, and they offer higher cyclic life and efficiency even during fast charge and discharge processes. In this dissertation, new techniques for the control and energy management of the hybrid battery-supercapacitor storage system are developed to improve the performance of the system in terms of efficiency, power quality and reliability. To evaluate the findings of this dissertation, a laboratory-scale DC microgrid system is designed and implemented. The developed microgrid utilizes a hybrid lead-acid battery and supercapacitor energy storage system and is loaded under various grid conditions. The developed microgrid has also real-time monitoring, control and energy management capabilities. A new control scheme and real-time energy management algorithm for an actively controlled hybrid DC microgrid is developed to reduce the adverse impacts of pulsed power loads. The developed control scheme is an adaptive current-voltage controller that is based on the moving average measurement technique and an adaptive proportional compensator. Unlike conventional energy control methods, the developed controller has the advantages of controlling both current and voltage of the system. This development is experimentally tested and verified. The results show significant improvements achieved in terms of enhancing the system efficiency, reducing the AC grid voltage drop and mitigating frequency fluctuation. Moreover, a novel event-based protection scheme for a multi-terminal DC power system has been developed and evaluated. In this technique, fault identification and classifications are performed based on the current derivative method and employing an artificial inductive line impedance. The developed scheme does not require high speed communication and synchronization and it transfers much less data when compared with the traditional method such as the differential protection approach. Moreover, this scheme utilizes less measurement equipment since only the DC bus data is required.

Recent increase in performance of High Performance Computing (HPC) systems has been followed by even higher increase in power consumption. Power draw of modern supercomputers leads to very high operating costs and reliability concerns. Furthermore, it has negative consequences on the environment. Accordingly, over the last decade there have been many works dealing with power/energy management in HPC systems. Since CPUs accounts for a high portion of the total system power consumption, our work aims at CPU power reduction. Dynamic Voltage Frequency Scaling (DVFS) is a widely used technique for CPU power management. Running an application at lower frequency/voltage reduces its power consumption. However, frequency scaling should be used carefully since it has negative effects on the application performance. We argue that the job scheduler level presents a good place for power management in an HPC center having in mind that a parallel job scheduler has a global overview of the entire system. In this thesis we propose power-aware parallel job scheduling policies where the scheduler determines the job CPU frequency, besides the job execution order. Based on the goal, the proposed policies can be classified into two groups: energy saving and power budgeting policies. The energy saving policies aim to reduce CPU energy consumption with a minimal job performance penalty. The first of the energy saving policies assigns the job frequency based on system utilization while the other makes job performance predictions. While for less loaded workloads these policies achieve energy savings, highly loaded workloads suffer from a substantial performance degradation because of higher job wait times due to an increase in load caused by longer job run times. Our results show higher potential of the DVFS technique when applied for power budgeting. The second group of policies are policies for power constrained systems. In contrast to the systems without a power limitation, in the case of a given power budget the DVFS technique even improves overall job performance reducing the average job wait time. This comes from a lower job power consumption that allows more jobs to run simultaneously. The first proposed policy from this group assigns CPU frequency using the job predicted performance and current power draw of already running jobs. The other power budgeting policy is based on an optimization problem which solution determines the job execution order, as well as power distribution among jobs selected for execution. This policy fully exploits available power and leads to further performance improvements. The last contribution of the thesis is an analysis of the DVFS technique potential for energyperformance trade-off in current and future HPC systems. Ongoing changes in technology decrease the DVFS applicability for energy savings but the technique still reduces power consumption making it useful for power constrained systems. In order to analyze DVFS potential, a model of frequency scaling impact on MPI application execution time has been proposed and validated against measurements on a large-scale system. This parametric analysis showed for which application/platform characteristic, frequency scaling leads to energy savings.
El aumento de rendimiento que han experimentado los sistemas de altas prestaciones ha venido acompañado de un aumento aún mayor en el consumo de energía. El consumo de los supercomputadores actuales implica unos costes muy altos de funcionamiento. Estos costes no tienen simplemente implicaciones a nivel económico sino también implicaciones en el medio ambiente. Dado la importancia del problema, en los últimos tiempos se han realizado importantes esfuerzos de investigación para atacar el problema de la gestión eficiente de la energía que consumen los sistemas de supercomputación. Dado que la CPU supone un alto porcentaje del consumo total de un sistema, nuestro trabajo se centra en la reducción y gestión eficiente de la energía consumida por la CPU. En concreto, esta tesis se centra en la viabilidad de realizar esta gestión mediante la técnica de Dynamic Voltage Frequency Scalingi (DVFS), una técnica ampliamente utilizada con el objetivo de reducir el consumo energético de la CPU. Sin embargo, esta técnica puede implicar una reducción en el rendimiento de las aplicaciones que se ejecutan, ya que implica una reducción de la frecuencia. Si tenemos en cuenta que el contexto de esta tesis son sistemas de alta prestaciones, minimizar el impacto en la pérdida de rendimiento será uno de nuestros objetivos. Sin embargo, en nuestro contexto, el rendimiento de un trabajo viene determinado por dos factores, tiempo de ejecución y tiempo de espera, por lo que habrá que considerar los dos componentes. Los sistemas de supercomputación suelen estar gestionados por sistemas de colas. Los trabajos, dependiendo de la política que se aplique y el estado del sistema, deberán esperar más o menos tiempo antes de ser ejecutado. Dado las características del sistema objetivo de esta tesis, nosotros consideramos que el Planificador de trabajo (o Job Scheduler), es el mejor componente del sistema para incluir la gestión de la energía ya que es el único punto donde se tiene una visión global de todo el sistema. En este trabajo de tesis proponemos un conjunto de políticas de planificación que considerarán el consumo energético como un recurso más. Estas políticas decidirán que trabajo ejecutar, el número de cpus asignadas y la lista de cpus (y nodos) sino también la frecuencia a la que estas cpus se ejecutarán. Estas políticas estarán orientadas a dos objetivos: reducir la energía total consumida por un conjunto de trabajos y controlar en consumo puntual de un conjunto puntual para evitar saturaciones del sistema en aquellos centros que puedan tener una capacidad limitada (permanente o puntual). El primer grupo de políticas intentará reducir el consumo total minimizando el impacto en el rendimiento. En este grupo encontramos una primera política que asigna la frecuencia de las cpus en función de la utilización del sistema y una segunda que calcula una estimación de la penalización que sufrirá el trabajo que va a empezar para decidir si reducir o no la frecuencia. Estas políticas han mostrado unos resultados aceptables con sistemas poco cargados, pero han mostrado unas pérdidas de rendimiento significativas cuando el sistema está muy cargado. Estas pérdidas de rendimiento no han sido a nivel de incremento significativo del tiempo de ejecución de los trabajos, pero sí de las métricas de rendimiento que incluyen el tiempo de espera de los trabajos (habituales en este contexto). El segundo grupo de políticas, orientadas a sistemas con limitaciones en cuanto a la potencia que pueden consumir, han mostrado un gran potencial utilizando DVFS como mecanismo de gestión. En este caso, comparado con un sistema que no incluya esta gestión, han demostrado mejoras en el rendimiento ya que permiten ejecutar más trabajos de forma simultánea, reduciendo significativamente el tiempo de espera de los trabajos. En este segundo grupo proponemos una política basada en el rendimiento del trabajo que se va a ejecutar y una segunda que considera la asignación de todos los recursos como un problema de optimización lineal. Esta última política es la contribución más importante de la tesis ya que demuestra un buen comportamiento en todos los casos evaluados. La última contribución de la tesis es un estudio del potencial de DVFS como técnica de gestión de la energía en un futuro próximo, en función de un estudio de las características de las aplicaciones, de la reducción de DVFS en el consumo de la CPU y del peso de la CPU dentro de todo el sistema. Este estudio indica que la capacidad de DVFS de ahorrar energía será limitado pero sigue mostrando un gran potencial de cara al control del consumo energético.

Este trabalho descreve os requisitos para definição, implantação, manutenção e melhoria de sistemas de gestão de energia no ambiente industrial com um enfoque sistemático no que se refere às rotinas de melhoria contínua para eficiência energética. Para tanto, propôs-se a estruturação de uma plataforma automatizada visando o monitoramento, verificação e gerenciamento de recursos energéticos compatível com um sistema de gestão de energia normatizado, incluindo os requisitos de uso e consumo de energia, além do monitoramento, documentação, comunicação, melhores práticas de projeto, aquisição de equipamentos, sistemas, processos e recursos humanos envolvidos no desempenho energético. A estratégia de análise do uso da energia proposta neste trabalho baseou-se na metodologia de monitoramento e gestão de índices que consiste em uma abordagem sistemática na utilização de recursos energéticos objetivando alcançar o melhor resultado econômico através da gestão permanente do consumo de energia. Além disso, propôs-se a inclusão dessa metodologia como um procedimento na fase de planejamento da norma ISO50001, a qual estabelece os conceitos para a implantação de sistemas de gestão de energia. Visando integrar as ferramentas associadas a este cenário, esta plataforma contempla o uso de um sistema de supervisão associado a um aplicativo (Soft-PLC) que executa a aplicação de controle do uso de energia em um ambiente industrial com automação distribuída compatível com a norma IEC61131. O projeto do aplicativo de controle do uso de energia foi conduzido adotando-se diferentes linguagens de programação definidas na IEC para executar todos os procedimentos de medição, monitoração e gestão exigidos pelo sistema, incluindo análise comparativa com as “melhores práticas”, uso de tecnologias inovadoras, abordagem de produto e serviço, auditoria energética e conformidade com marcos regulatórios. Os resultados decorrentes da adoção de uma plataforma baseada em automação para o gerenciamento energético incluem elevada flexibilidade, adaptabilidade e usabilidade do sistema. Além disso, um projeto de automação neste cenário de plataforma aberta tende a apresentar menores custos de desenvolvimento e implantação.
This work describes the requirements for the definition, implementation, maintenance and improvement of energy management systems in the industrial environment with a systematic approach concerning continuous improvement routines for energy efficiency. For this purpose, it was proposed the establishment of a framework based on automation to implement monitoring, verification and management of energy resources compatible with a standardized energy management system, including requirements for energy use and consumption, in addition to monitoring, documentation, communication, project best practices, equipment acquisition, systems, processes and human resources involved in energy performance. The strategy of energy use analysis proposed in this work is based on the methodology of monitoring and targeting that consists of a systematic approach in the use of energy resources in order to achieve the best economic result through the permanent management of energy consumption. Furthermore, this work includes that system as a procedure in the planning phase of ISO50001 standard which establishes the concepts for energy management systems implementation. In order to aggregate all tools associated to this scenario, this paper proposes the use of a supervisory tool integrated to a real-time software (Soft-PLC) that runs the control application and a factory floor distributed system automation hardware in an IEC61131 compatible environment. The project of the control application of energy use was conducted using different programming languages defined in IEC to perform all the procedures of measurement, monitoring and management required by the system, including comparative analysis with the "best practices", use of innovative technologies, product and service approach, energy audit and compliance with regulatory milestones. The expected results of adopting an automation-based platform for energetic management include system flexibility, adaptability and usability. Besides, a project of automation in this scenario of open platform tends to introduce lower development and deployment costs.

This thesis is devoted to the study of the optimisation-based control techniques for the design of control strategies that contribute to improve the energy efficiency of smart manufacturing systems. Currently, manufacturing industry is suffering a transformation towards smart, flexible, and energy-efficient manufacturing systems. This transformation requires modularised and reconfigurable manufacturing systems to respond to changes in productions programs and to the time-varying pieces demand while keeping an energy-efficient operation. Thus, suitable control systems should be designed to satisfy the requirements of this transformation while minimising the energy consumption and maximising the plant profit. In this regard, optimisation-based controllers are suitable for the design of control systems that minimise the total energy consumption of such systems while remaining their productivity taking into account the operational conditions and the factors that affect them. First, this dissertation presents how optimisation-based control techniques can contribute to face the challenges of the smart manufacturing systems. Based on this review, manufacturing industry is classified by levels, i.e., machine, process line, and plant levels, for the design of optimisation-based controllers. Besides, to design control strategies that do not affect plant productivity, manufacturing systems are also classified according to the operations performed. Based on these classifications, control strategies are proposed to minimise either the total energy consumption of manufacturing systems or the energy costs related to the operation of such systems. At both machine and process line levels, control strategies are designed based on model predictive control approach to minimise their energy consumption. The underlying idea behind the proposed control strategies consists of managing independently those devices (or systems) that are not directly involved in the machining operations. Thus, energy consumption models are required to predict the total energy consumption profile of manufacturing systems and, based on this, to select the activation/deactivation instants of the manipulated devices that minimise their energy consumption and guarantee their proper operation. Next, due to at the process line level the size and complexity of manufacturing systems increases, a control strategy based on two control modes is proposed to reduce the computational burden of such controllers by switching from a control mode based on online optimisation to an autonomous control mode without solving an optimisation problem. Since the need for flexible and reconfigurable manufacturing systems, non-centralised control strategies are proposed at higher industrial levels to minimise their energy consumption. Thus, both cooperative and non-cooperative local controllers are designed considering a fixed system partitioning and using alternative direction methods of multipliers to solve the optimisations problems in a distributed fashion. Besides, due to the nature of the proposed control objectives, a way to define the consensus stage among the local controllers with coupled dynamics is proposed. Finally, the control strategies designed at plant level are based on the economic model predictive control approach to maximise the plant profit and minimise the operational costs related to the plant operation. At this level, control objectives are focused on determining the economic-optimal production programming of the plant that the control strategies at lower levels should follow. In this regard, the production programming of the plant is determined taking into account the pieces demand, the energy consumption of manufacturing systems, and the current energy market and their fluctuations. All control strategies proposed in this thesis are tested in simulation considering different scenarios designed based on the real operation of an automotive part manufacturing plant.
Esta tesis se basa en el estudio de las técnicas de control basadas en optimización para el diseño de estrategias de control que mejoren la eficiencia energética de los sistemas de manufactura inteligentes. La industria de manufactura se está transformando hacia sistemas de manufactura inteligentes, flexibles y eficientes energéticamente, que requiere de estructuras modulares y reconfigurables para poder responder a los cambios en la programación de la producción y la demanda de piezas. Así, se deben diseñar sistemas de control que cumplan los requerimientos de dicha transformación mientras minimizan el consumo de energía y maximizan la rentabilidad de la planta. En este sentido, los controladores basados en optimización son adecuados para el diseño de sistemas de control que minimicen el consumo de energía de dichos sistemas mientras mantienen su productividad teniendo en cuenta los factores que los afectan. Primero, se presentan como las técnicas de control basadas en optimización pueden contribuir a hacer frente a los desafíos impuestos por la industria de manufactura. Con base en esta revisión, la industria manufacturera se clasifica por niveles, nivel de máquina, línea de proceso, y planta, para el diseño de controladores basados en optimización. Además, para diseñar estrategias de control que no afecten la productividad de la planta, se propone una clasificación para estos sistemas en función de las operaciones realizadas. Con base en estas clasificaciones, se diseñan estrategias de control que minimicen el consumo de energía de los sistemas de manufactura o los costos asociados a dicho consumo. A los niveles de maquina y línea, se diseñaron estrategias de control para minimizar el consumo de energía de los sistemas de manufactura con base en el enfoque de control predictivo basado en modelo. Las estrategias propuestas se basan en la gestión independiente de aquellos dispositivos que no están directamente relacionados con las operaciones de mecanizado. Por lo tanto, modelos de consumo de energía fueron necesarios para predecir el perfil del consumo de energía de estos sistemas y, a partir de esto, seleccionar los instantes de activación/desactivación de los dispositivos manipulados que minimicen el consumo de energía y garanticen el correcto funcionamiento de dichos sistemas. Dado que al nivel de línea el tamaño y la complejidad de estos sistemas aumenta, se propone a una estrategia de control basada en dos modos de control para reducir la carga computacional mediante la conmutación de un modo de control basado en optimización a un modo autónomo que no requiere optimización. Dada la necesidad de sistemas de manufactura flexibles y reconfigurables, estrategias de control no centralizadas se proponen para minimizar el consumo de dichos sistemas a los niveles más altos. Para este fin, los sistemas de manufactura se dividieron en subsistemas, y se diseñaron controladores locales de tipo cooperativo y no cooperativo usando métodos alternativos de dirección de multiplicadores para resolver los problemas de optimización. Además, debido a la naturaleza de los objetivos de control propuesto, se propuso una forma de establecer el consenso entre los controladores locales con dinámicas acopladas. Finalmente, a nivel de planta, se diseñan estrategias de control con base en el enfoque control predictivo basado en modelo económico para maximizar la rentabilidad de la planta. A este nivel, los objetivos de control se centran en determinar la programación de la producción óptima que deberán seguir las estrategias de control diseñadas a niveles más bajos. Así, la programación de la producción de la planta se determina teniendo en cuenta la demanda de piezas, el consumo de energía total, y el mercado energético con sus fluctuaciones. Las estrategias de control propuestas en esta tesis se probaron en simulación considerando diferentes escenarios diseñados con base en la operación real de una planta de fabricación de piezas automotrices.
Aquesta tesi es centra principalment en l’estudi de les tècniques de control basades en optimització per al disseny d’estratègies que contribueixin a millorar l’eficiència energètica dels sistemes de manufactura intel·ligents. Actualment, la indústria manufacturera està experimentant una transformació cap a sistemes de manufactura intel·ligents, flexibles i eficients energèticament, impulsada pels avenços en dispositius de mesura, gestió de dades i eines de comunicació i connectivitat. Aquesta transformació requereix que els sistemes de manufactura siguin modulars i reconfigurables per poder respondre als canvis en la programació de la producció i de la demanda i disseny de les peces mentre continuen operant de manera eficient i sostenible. Per tant, per tal d’assolir una indústria de manufactura m’és intel·ligent, s’han de dissenyar sistemes de control adequats que permetin complir els requeriments d’aquesta transformació, així com també minimitzar el consum d’energia i maximitzar la rendibilitat de la planta. En aquest sentit, els controladors basats en optimització i les arquitectures de control no centralitzat podrien ser adequats per al disseny de sistemes de control que contribueixin a minimitzar el consum d’energia total d’aquests sistemes mentre mantenen la seva productivitat i tenen en compte les restriccions operatives i els factors externs que afecten aquests sistemes. Per tant, mitjançant l’ús d’estratègies de control avançat, els sistemes de control poden ser degudament actualitzats per incloure la informació sobre els canvis en l’operació dels sistemes de manufactura, així com també la variació del mercat energètic per minimitzar els costos d’energia durant l’operació de la planta. Primer, en aquesta tesi, es presenten i discuteixen les estratègies actualment implementades en la indústria manufacturera per millorar la seva eficiència energètica. En base a aquesta revisió, s’identifiquen les principals bretxes de recerca en aquest camp i es discuteix com les tècniques de control basades en optimització poden contribuir a fer front als desafiaments imposats per la nova era de la indústria manufacturera (Industry 4.0). Recolzant-se en la revisió de la literatura, es proposa classificar la indústria manufacturera per nivells, considerant el nivell de màquina, línia de procés i planta, per al disseny de controladors basats en optimització. A més, per tal de dissenyar estratègies de control que no afectin la productivitat de la planta, és a dir, el nombre de peces processades per unitat de temps, els elements constitutius dels sistemes de manufactura també es classifiquen en dispositius de mecanitzat i perifèrics en funció de les operacions realitzades. Els elements de la primera classe corresponen a aquells que estan directament involucrats en les operacions de mecanitzat, mentre que els de la segona classe són aquells que s’encarreguen de proveir els recursos requerits pels dispositius de mecanitzat. Després, en base a aquesta classificació, es proposen estratègies de control en cada nivell per minimitzar el seu consum d’energia o els costos associats a aquest consum. Per als nivells de màquina i línia de procés, es dissenyen estratègies de control per minimitzar el consum d’energia dels sistemes de manufactura en base a l’enfocament de control predictiu basat en model. Les estratègies proposades es basen en la idea de gestionar de manera independent els dispositius (o sistemes) perifèrics per tal de no afectar el temps de processament de les màquines tot mantenint l’operació dels dispositius de mecanitzat. Per tant, calen models de consum d’energia per a predir el perfil de consum d’energia dels sistemes de manufactura i, en base a aquesta predicció, seleccionar els instants d’activació / desactivació per als dispositius manipulats a partir dels quals es minimitzi el consum d’energia total i es pugui garantir el correcte funcionament d’aquests sistemes. D’altra banda, atès que al nivell de línia de procés la mida i la complexitat dels sistemes de manufactura augmenta, es proposa una estratègia de control basada en dos modes de control per tal de reduir la càrrega computacional i dissenyar controladors que puguin ser implementats en temps real. En aquest sentit, tenint en compte que els sistemes de manufactura presenten un comportament diari, es proposa un algoritme per detectar la periodicitat d’aquests sistemes i, després, commutar a un mode de control autònom que no requereixi resoldre un problema d’optimització en línia. D’altra banda, donada la necessitat de sistemes de manufactura flexibles i reconfigurables, es proposen estratègies de control no centralitzades per minimitzar el consum d’energia dels sistemes de fabricació als nivells més alts. Amb aquesta finalitat, els sistemes de manufactura es divideixen en subsistemes, i es dissenyen controladors locals de tipus cooperatiu i no cooperatiu utilitzant mètodes alternatius de direcció de multiplicadors per resoldre els problemes d’optimització de manera distribuïda. A més, a causa de la naturalesa de l’objectiu de control proposat, el qual està enfocat en minimitzar el consum d’energia dels sistemes de manufactura, es proposa una forma d’establir el consens entre els controladors locals amb dinàmiques acoblades. Després, les estratègies de control proposades són extrapolades al nivell de planta usant objectius de tipus econòmic, i es comparen les arquitectures de control centralitzat i no centralitzat pel que fa al seu acompliment en llac¸ tancat i la càrrega computacional requerida per trobar una solució. Finalment, a nivell de planta, es dissenyen estratègies de control en base a l’enfocament de control predictiu basat en model econòmic per tal de maximitzar la rendibilitat de la planta i minimitzar els costos associats a la seva operació. Per tant, a aquest nivell, els objectius de control se centren a determinar la programació de la producció òptima de la planta que hauran de seguir les estratègies de control dissenyades als nivells més baixos. En aquest sentit, la programació de la producció de la planta és determinada tenint en compte la demanda actual de peces, el consum d’energia dels sistemes de manufactura i el mercat energètic amb les seves fluctuacions. Totes les estratègies de control proposades en aquesta tesi es proven en simulació considerant diferents escenaris basats en l’operació real d’una planta de fabricació de peces automotrius.

The efficient and flexible management of large datasets is one of the core requirements of modern business applications. Having access to consistent and up-to-date information is the foundation for operational, tactical, and strategic decision making. Within the last few years, the database community sparked a large number of extremely innovative research projects to push the envelope in the context of modern database system architectures. In this paper, we outline requirements and influencing factors to identify some of the hot research topics in database management systems. We argue that—even after 30 years of active database research—the time is right to rethink some of the core architectural principles and come up with novel approaches to meet the requirements of the next decades in data management. The sheer number of diverse and novel (e.g., scientific) application areas, the existence of modern hardware capabilities, and the need of large data centers to become more energy-efficient will be the drivers for database research in the years to come.

Nowadays, energy is absolutely necessary all over the world. Taking into account the advantages that it presents in transport and the needs of homes and industry, energy is transformed into electricity. Bearing in mind the expansion of electricity, initiatives like Horizon 2020, pursue the objective of a more sustainable future: reducing the emissions of carbon and electricity consumption and increasing the use of renewable energies. As an answer to the shortcomings of the traditional electrical network, such as large distances to the point of consumption, low levels of flexibility, low sustainability, low quality of energy, the difficulties of storing electricity, etc., Smart Grids (SG), a natural evolution of the classical network, has appeared. One of the main components that will allow the SG to improve the traditional grid is the Energy Management System (EMS). The EMS is necessary to carry out the management of the power network system, and one of the main needs of the EMS is a prediction system: that is, to know in advance the electricity consumption. Besides, the utilities will also require predictions to manage the generation, maintenance and their investments. Therefore, it is necessary to dispose of the systems of prediction of the electrical consumption that, based on the available data, forecast the consumption of the next hours, days or months, in the most accurate way possible. It is in this field where the present research is placed since, due to the proliferation of sensor networks and more powerful computers, more precise prediction systems have been developed. Having said that, a complete study has been realized in the first work, taking into account the need to know, in depth, the state of the art, in relation to the load forecasting topic. On the basis of acquired knowledge, the installation of sensor networks, the collection of consumption data and modelling, using Autoregressive (AR) models, were performed in the second work. Once this model was defined, in the third work, another step was made, collecting new data, such as building occupancy, meteorology and indoor ambience, testing several paradigmatic models, such as Multiple Linear Regression (MLR), Artificial Neural Network (ANN) and Support Vector Regression (SVR), and establishing which exogenous data improves the prediction accuracy of the models. Reaching this point, and having corroborated that the use of occupancy data improves the prediction, there was the necessity of generating techniques and methodologies, in order to have the occupancy data in advance. Therefore, several attributes of artificial occupancy were designed, in order to perform long-term hourly consumption predictions, in the fourth work.
A dia d’avui l’energia és un bé completament necessari arreu del món. Degut als avantatges que presenta en el transport i a les necessitats de les llars i la indústria, l’energia és transformada en energia elèctrica. Tenint en compte la total expansió i domini de l’electricitat, iniciatives com Horitzó 2020, tenen per objectiu un futur més sostenible: reduint les emissions de carboni i el consum i incrementant l’ús de renovables. Partint dels defectes de la xarxa elèctrica clàssica, com són gran distància al punt de consum, poca flexibilitat, baixa sostenibilitat, baixa qualitat de l’energia, dificultats per a emmagatzemar energia, etc. apareixen les Smart Grid (SG), una evolució natural de la xarxa clàssica. Un dels principals elements que permetrà a les SG millorar les xarxes clàssiques és l’Energy Management System (EMS). Així doncs, per a que l’EMS pugui dur a terme la gestió dels diversos elements, una de les necessitats bàsiques dels EMS serà un sistema de predicció, o sigui, saber per endavant quin consum hi haurà en un entorn determinat. A més, les empreses subministradores d’electricitat també requeriran de prediccions per a gestionar la generació, el manteniment i fins i tot les inversions a llarg termini. Així doncs ens calen sistemes de predicció del consum elèctric que, partint de les dades disponibles, ens subministrin el consum que hi haurà d’aquí a unes hores, uns dies o uns mesos, de la manera més aproximada possible. És dins d’aquest camp on s’ubica la recerca que presentem. Degut a la proliferació de xarxes de sensors i computadors més potents, s’han pogut desenvolupar sistemes de predicció més precisos. A tall de resum, en el primer treball, i tenint en compte que s’havia de conèixer en profunditat l’estat de la qüestió en relació a la predicció del consum elèctric, es va fer una anàlisi completa de l’estat de l’art. Un cop fet això, i partint del coneixement adquirit, en el segon treball es va dur a terme la instal•lació de les xarxes de sensors, la recollida de dades de consum i el modelatge amb models lineals d’auto-regressió (AR). En el tercer treball, un cop fets els models es va anar un pas més enllà recollint dades d’ocupació, de meteorologia i ambient interior, provant diferents models paradigmàtics com Multiple Linear Regression (MLR), Artificial Neural Network (ANN) i Support Vector Regression (SVR) i establint quines dades exògenes milloren la predicció dels models. Arribat a aquest punt, i havent corroborat que l’ús de dades d’ocupació millora la predicció, es van generar tècniques per tal de disposar de les dades d’ocupació per endavant, o sigui a hores vista. D’aquesta manera es van dissenyar diferents atributs d’ocupació artificials, permetent-nos fer prediccions horàries de consum a llarg termini. Aquests conceptes s’expliquen en profunditat al quart treball.

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; in conjunction with the Leaders for Global Operations Program at MIT, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 87-91).
Data centers consume approximately 1.5% of total US electricity and 0.8% of the total world electricity, and this percentage will increase with the integration of technology into daily lives. In typical data centers, valued added IT equipment such as memory, servers, and networking account for less than one half of the electricity consumed, while support equipment consumes the remaining electricity. The purpose of this thesis is to present the results of developing, testing, and implementing a low-cost, systematic approach for increasing the energy efficiency of data centers. The pilot process was developed using industry best practices, and was piloted at a Raytheon site in Garland, TX. Because the approach is low-cost, there is an emphasis on increasing the energy efficiency of data centers' heat removal and lighting equipment. The result of implementing the low-cost systematic approach, consisting of both technical and behavior modifications, was a 23% reduction in electricity consumption, leading to annual savings of over $53,000. The improvement to the heat removal equipment's energy efficiency was 54%. In addition to presenting the results of the pilot, recommendations for replicating the pilot's success are provided. Two major managerial techniques are described - creating an aligned incentive structure in both Facilities and IT departments during the data center design phase, and empowering employees to make improvements during the use phase. Finally, a recommended roll out plan, which included a structure for Data Center Energy Efficiency Rapid Results Teams, is provided.
by Jeremy M. Stewart.
S.M.
M.B.A.

The requirements on fuel consumption and emissions for passenger cars are getting stricter every year. This has forced the vehicle industry to look for ways to improve the performance of the driveline. With the increasing focus on electrification, a common method is to combine an electrical driveline with a conventional driveline that uses a petrol or diesel engine, thus creating a hybrid electric vehicle. To fully be able to utilise the potential of the driveline in such a vehicle, an efficient energy management strategy is needed. This thesis describes the development of an efficient route-based energy management strategy. Three different optimisation strategies are combined, deterministic dynamic programming, equivalent consumption minimisation strategy and convex optimisation, together with segmentation of the input data. The developed strategy shows a decrease in computational time with up to more than one hundred times compared to a benchmark algorithm. When implemented in Volvo's simulation tool, VSim, substantial fuel savings of up to ten percent is shown compared to a charge-depleting charge-sustain strategy.

Кваліфікаційна робота магістра становить 87 сторінки, в тому числі 29 рисунків, одна таблиця, бібліографії із 45 джерел на п’яти сторінках, одного додатку на 4 сторінках. Мета дослідження. Підвищення енергоефективності та конкурентоспроможності підприємств Сумського регіону на основі впровадження систем енергетичного менеджменту шляхом розроблення типового електронного пакет нормативного забезпечення, що відповідає принципам та вимогам ДСТУ ISO 50001:2014. Для досягнення поставленої мети були встановлені наступні завдання дослідження: 1) дослідити досвід країн ЄС щодо підвищення енергоефективності економік країн-членів; 2) дослідити вимоги міжнародних стандартів щодо систем управління енергоефективністю та оцінювання енергетичних послуг для споживачів; 3) розробити типовий електронний пакет нормативного забезпечення системи енергетичного менеджменту, що б відповідав вимогам ДСТУ ISO 50001:2014. Наукова новизна отриманих результатів. Вперше запропонована на основі застосування програмного середовищі Microsoft Excel принципи розробки типового електронного пакету нормативного забезпечення з розроблення та впровадження система енергетичного управління, який повністю відповідає принципам та вимогам ДСТУ ISO 50001:2014 та дозволяє управляти документацією системи менеджменту в електронному вигляді. Практичне значення отриманих результатів. В роботі запропоновано типовий електронний пакет нормативного забезпечення розробки та впровадження система енергетичного управління, який повністю відповідає принципам та вимогам ДСТУ ISO 50001:2014.
Квалификационная работа магистра составляет 87 страницы, в том числе 29 рисунков, одна таблица, библиографии из 45 источников на пяти страницах, одного приложения на 4 страницах. Цель исследования. Повышение энергоэффективности и конкурентоспособности предприятий Сумского региона на основе внедрения систем энергетического менеджмента путем разработки типового электронного пакет нормативного обеспечения, отвечающего принципам и требованиям ДСТУ ISO 50001: 2014. Для достижения поставленной цели были установлены следующие задачи: 1) исследовать опыт стран ЕС по повышению энергоэффективности экономик стран-членов; 2) исследовать требования международных стандартов систем управления энергоэффективностью и оценки энергетических услуг для потребителей; 3) разработать типовой электронный пакет нормативного обеспечения системы энергетического менеджмента, чтобы отвечал требованиям ДСТУ ISO 50001: 2014. Научная новизна полученных результатов. Впервые предложена на основе применения программного среде Microsoft Excel принципы разработки типового электронного пакета нормативного обеспечения по разработке и внедрению системы энергетического управления, который полностью соответствует принципам и требованиям ДСТУ ISO 50001: 2014 и позволяет управлять документацией системы менеджмента в электронном виде. Практическое значение полученных результатов. В работе предложен типовой электронный пакет нормативного обеспечения разработки и внедрения система энергетического управления, который полностью соответствует принципам и требованиям ДСТУ ISO 50001: 2014.
The master's qualification is 87 pages, including 29 drawings, one table, bibliographies from 45 sources on five pages, one application on 4 pages. The aim of the study. Improvement of energy efficiency and competitiveness of Sumy region enterprises based on the implementation of energy management systems by developing a standard electronic regulatory package that meets the principles and requirements of DSTU ISO 50001: 2014. To achieve this goal, the following research objectives have been set: 1) to examine the experience of EU countries in improving the energy efficiency of Member States' economies; 2) explore the requirements of international standards for energy efficiency management systems and the evaluation of energy services for consumers; 3) develop a standard electronic package of regulatory support for the energy management system that would meet the requirements of DSTU ISO 50001: 2014. Scientific novelty of the obtained results. For the first time, based on the application of the Microsoft Excel software environment, the principles of developing a standard electronic regulatory package for the development and implementation of an energy management system that fully complies with the principles and requirements of DSTU ISO 50001: 2014 and allows you to manage the documentation of the management system in electronic form. The practical significance of the results obtained. The paper proposes a standard electronic package of regulatory support for the development and implementation of an energy management system that fully complies with the principles and requirements of DSTU ISO 50001: 2014.

The efficacy of the energy management systems at dealing with energy consumption in buildings has been a topic with a growing interest in recent years due to the ever-increasing global energy demand and the large percentage of energy being currently used by buildings. The scale of this sector has attracted research effort with the objective of uncovering potential improvement avenues and materializing them with the help of recent technological advances that could be exploited to lower the energetic footprint of buildings. Specifically, in the area of heating, ventilating and air conditioning installations, the availability of large amounts of historical data in building management software suites makes possible the study of how resource-efficient these systems really are when entrusted with ensuring occupant comfort. Actually, recent reports have shown that there is a gap between the ideal operating performance and the performance achieved in practice. Accordingly, this thesis considers the research of novel energy management strategies for heating, ventilating and air conditioning installations in buildings, aimed at narrowing the performance gap by employing data-driven methods to increase their context awareness, allowing management systems to steer the operation towards higher efficiency. This includes the advancement of modeling methodologies capable of extracting actionable knowledge from historical building behavior databases, through load forecasting and equipment operational performance estimation supporting the identification of a building’s context and energetic needs, and the development of a generalizable multi-objective optimization strategy aimed at meeting these needs while minimizing the consumption of energy. The experimental results obtained from the implementation of the developed methodologies show a significant potential for increasing energy efficiency of heating, ventilating and air conditioning systems while being sufficiently generic to support their usage in different installations having diverse equipment. In conclusion, a complete analysis and actuation framework was developed, implemented and validated by means of an experimental database acquired from a pilot plant during the research period of this thesis. The obtained results demonstrate the efficacy of the proposed standalone contributions, and as a whole represent a suitable solution for helping to increase the performance of heating, ventilating and air conditioning installations without affecting the comfort of their occupants.
L’eficàcia dels sistemes de gestió d’energia per afrontar el consum d’energia en edificis és un tema que ha rebut un interès en augment durant els darrers anys a causa de la creixent demanda global d’energia i del gran percentatge d’energia que n’utilitzen actualment els edificis. L’escala d’aquest sector ha atret l'atenció de nombrosa investigació amb l’objectiu de descobrir possibles vies de millora i materialitzar-les amb l’ajuda de recents avenços tecnològics que es podrien aprofitar per disminuir les necessitats energètiques dels edificis. Concretament, en l’àrea d’instal·lacions de calefacció, ventilació i climatització, la disponibilitat de grans bases de dades històriques als sistemes de gestió d’edificis fa possible l’estudi de com d'eficients són realment aquests sistemes quan s’encarreguen d'assegurar el confort dels seus ocupants. En realitat, informes recents indiquen que hi ha una diferència entre el rendiment operatiu ideal i el rendiment generalment assolit a la pràctica. En conseqüència, aquesta tesi considera la investigació de noves estratègies de gestió de l’energia per a instal·lacions de calefacció, ventilació i climatització en edificis, destinades a reduir la diferència de rendiment mitjançant l’ús de mètodes basats en dades per tal d'augmentar el seu coneixement contextual, permetent als sistemes de gestió dirigir l’operació cap a zones de treball amb un rendiment superior. Això inclou tant l’avanç de metodologies de modelat capaces d’extreure coneixement de bases de dades de comportaments històrics d’edificis a través de la previsió de càrregues de consum i l’estimació del rendiment operatiu dels equips que recolzin la identificació del context operatiu i de les necessitats energètiques d’un edifici, tant com del desenvolupament d’una estratègia d’optimització multi-objectiu generalitzable per tal de minimitzar el consum d’energia mentre es satisfan aquestes necessitats energètiques. Els resultats experimentals obtinguts a partir de la implementació de les metodologies desenvolupades mostren un potencial important per augmentar l'eficiència energètica dels sistemes de climatització, mentre que són prou genèrics com per permetre el seu ús en diferents instal·lacions i suportant equips diversos. En conclusió, durant aquesta tesi es va desenvolupar, implementar i validar un marc d’anàlisi i actuació complet mitjançant una base de dades experimental adquirida en una planta pilot durant el període d’investigació de la tesi. Els resultats obtinguts demostren l’eficàcia de les contribucions de manera individual i, en conjunt, representen una solució idònia per ajudar a augmentar el rendiment de les instal·lacions de climatització sense afectar el confort dels seus ocupants

The collateral effects of fossil fuels push humanity to seek solutions to these adversities. Energy efficiency and renewable energies have gone from being almost imaginary concepts to necessary. Several studies have shown that self-sufficiency through photovoltaic systems and wind energy is possible. In addition, it is necessary a storage of the surpluses of both since it increases notably the efficiency of these systems and supposes to the short/medium term a saving of money in the consumer. Due to the mentioned before, the aim of the thesis is to convert a science park located in a cold climate such as Sweden into a complex that does not depend energetically on external sources. For this purpose, a series of data from the park were first collected and then simulated and optimised using the HOMER software for different energy configurations. At the same time, a computer code was created in MatLab to enable the energy produced to be used responsibly. The proposed system consists of PV panels, wind turbines and a battery. Thanks to it, a 64 % renewable fraction is achieved, which means a reduction of 27.45 tons of CO2 per year. In addition, through the energy management system created, the electricity contract is reduced, reducing the purchase of electricity during peak hours. It is concluded that the implementation of both proposed systems contributes significantly to the achievement of the sustainable goals set for 2 030 by the main world leaders, even though a total disconnection with the electrical grid has not been achieved.

Large cooling systems consume up to 25% of the total electricity used on deep level mines. These systems are integrated with the water reticulation system to provide chilled service water and cool ventilation air. Improving the energy efficiency of these large cooling systems is an important electrical demand-side management initiative. However, it is critical that the service delivery and system performance be maintained so as to not adversely affect productivity. A novel demand-side management strategy, based on variable water flow, was developed to improve the energy efficiency of large cooling systems like those found on deep mines. The strategy focuses on matching the cooling system supply to the demand through the use of modern energy efficient equipment, such as variable speed drives. The strategy involves the modulation of evaporator, condenser, bulk air cooler and pre-cooling water according to partial load conditions. A unique central energy management system was developed to integrate the proposed strategies on large cooling systems. The system features a generic platform and hierarchical network architecture. Real-time energy management is achieved through monitoring, optimally controlling and reporting on the developed strategy. The system is robust and versatile and can be applied to various large cooling systems. The feasibility of the strategy and energy management system was first investigated through the use of an adapted and verified simulation model and a techno-economic analysis. The strategy was then implemented on four large mine cooling systems and its in situ performance was assessed as experimental validation. The results of the Kusasalethu surface cooling system are discussed in detail as a primary case study while the results of the Kopanang, South Deep South Shaft and South Deep Twin Shaft cooling systems are summarised as secondary case studies. The potential to extend the variable water flow strategy to other industrial cooling systems is assessed through an investigation on the cooling system of the Saldanha Steel plant. Results indicate that, over a period of three months, average electrical load savings of 606-2 609 kW (29.3-35.4%) are realised on the four systems with payback periods of 5-17 months. The average electrical load saving between the sites is 33.3% at an average payback period of 10 months. The service delivery and performance of the cooling system and its critical subsystems are not adversely affected. The potential to extend the method to other large cooling systems is also shown. The developed variable water flow strategy is shown to improve the energy efficiency of large cooling systems, making a valuable contribution towards a more sustainable future. This thesis is presented as a detailed discussion of the entire research process. The key results have also been summarised in a series of five research articles attached as independent annexures. Three articles have been published in international scientific journals, one has been presented at and published in the proceedings of an international conference and one is still under review.
Thesis (PhD (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013

In the last two decades, energy is becoming one of the main issues in the manufacturing industry as it contributes substantially to production cost, CO2 emissions, and other destructive environmental impact. Due to rising energy costs, environmental concerns and stringent regulations, manufacturing is increasingly driven towards sustainable manufacturing which needs to address the associated environmental, social and economic aspects simultaneously. One common approach is to achieve sustainability and to implement energy-resource efficient production management systems that enable optimisation of energy consumption and resource utilisation in the production system. However, by reducing energy consumption, the product quality and production cost may be compromised. To remain competitive in the dynamic environment, the energy-efficient management system should not only concern energy consumption but also maintain product quality and production efficiency. This thesis presents a development of the Energy-smart Production Management (e-ProMan) system which provides a systematic, virtual simulation that integrates manufacturing data relating to thermal effect and correlation analysis between energy flow, work flow and data flow for the heating, ventilation and air conditioning (HVAC) system and production process. First, the e-ProMan system comprises of the multidimensional analysis between energy flow, work flow and data flow. The results showed that the product quality is significantly affected by ambient temperature in CNC precision machining. Product quality appears to be improved at lower temperatures. This research highlights the significance of ambient temperature in sustainable precision machining. Second, the simulation experiment was modelled at the production process due to it being the main source of energy consumption in manufacturing. An up-hill workload scenario was found to be the most energy and cost-efficient production processes. In other words, energy consumption, CO2 emission and total manufacturing cost could be reduced when workload capacity and operating machine increase incrementally. Moreover, the e-ProMan system was modelled and simulated using the weather forecast and real-time ambient temperature to reduce energy consumption of the HVAC system. The e-ProMan system results in less energy consumption compared to the fuzzy control system. To conclude, the e-ProMan demonstrates energy efficiency at all relevant levels in the manufacturing: machine, process and plant. For the future research, the e-ProMan system needs to be applied and validated in actual manufacturing environments.

Stand-alone hybrid energy systems are an attractive option for remote communities without a connection to a main power grid. However, the intermittent nature of solar and other renewable sources adversely affects the reliability with which these systems respond to load demands. Hybridisation, achieved by combining renewables with combustion-based supplementary prime movers, improves the ability to meet electric load requirements. In addition, the waste heat generated from backup Internal Combustion Engines or Micro Gas Turbines can be used to satisfy local heating and cooling loads. As a result, there is an expectation that the overall efficiency and Greenhouse Gas Emissions of stand-alone systems can be significantly improved through waste heat recovery. The aims of this PhD project are to identify how incremental increases to the hardware complexity of hybridised stand-alone energy systems affect their cost, efficiency, and CO2 footprint. The research analyses a range of systems, from those designed to meet only power requirements to others satisfying power and heating (Combined Heat and Power), or power plus both heating and cooling (Combined Cooling, Heating, and Power). The majority of methods used focus on MATLAB-based Genetic Algorithms (GAs). The modelling deployed finds the optimal selection of hardware configurations which satisfy single- or multi-objective functions (i.e. Cost of Energy, energy efficiency, and exergy efficiency). This is done in the context of highly dynamic meteorological (e.g. solar irradiation) and load data (i.e. electric, heating, and cooling). Results indicate that the type of supplementary prime movers (ICEs or MGT) and their minimum starting thresholds have insignificant effects on COE but have some effects on Renewable Penetration (RP), Life Cycle Emissions (LCE), CO2 emissions, and waste heat generation when the system is sized meeting electric load only. However, the transient start-up time of supplementary prime movers and temporal resolution have no significant effects on sizing optimisation. The type of Power Management Strategies (Following Electric Load-FEL, and Following Electric and Following Thermal Load- FEL/FTL) affect overall Combined Heating and Power (CHP) efficiency and meeting thermal demand through recovered heat for a system meeting electric and heating load with response to a specific load meeting reliability (Loss of Power Supply Probability-LPSP). However, the PMS has marginal effects on COE. The Electric to Thermal Load Ratio (ETLR) has no effects on COE for PV/Batt/ICE but strongly affects PV/Batt/MGT-based hybridised CHP systems. The higher thermal than the electric loads lead to higher efficiency and better environmental footprint. Results from this study also indicate that for a stand-alone hybridised system operating under FEL/FTL type PMS, the power only system has lower cost compared to the CHP and the Combined Cooling, Heating, and Power (CCHP) systems. This occurs at the expense of overall energy and exergy efficiencies. Additionally, the relative magnitude of heating and cooling loads have insignificant effects on COE for PV/Batt/ICE-based system configurations, however this substantially affects PV/Batt/MGT-based hybridised CCHP systems. Although there are no significant changes in the overall energy efficiency of CCHP systems in relation to variations to heating and cooling loads, systems with higher heating demand than cooling demand lead to better environmental benefits and renewable penetration at the cost of Duty Factor. Results also reveal that the choice of objective functions do not affect the system optimisation significantly.

The Oil and Gas (O&G) Industry has been one of the most environmentally questioned sectors in the lastdecades, where the management of the resources and impact over natural life has been severelycriticized. There are many adverse effects of the activities around the O&G business, from which theconsumption of energy and the emissions of Greenhouse Gases (GHG) stand out to be one of the mostimportant aspects to mitigate. This project studies the actual EnMS in E&P and develops measures of improvement using establishedmanagement tools in the division, applying the principles of the ISO 50001 Standard, to include energysavings and GHG emissions mitigation in the lifecycle of Repsol’s E&P operated assets. The main focuslands over three core elements: the Integrated Project Management platform for new projects, the EnergyPlanning follow-up applications, and the implementation of relevant energy audit outlines.

In recent years many companies have investigated the use of hybrid technology due to the potential of increasing the driveline’s efficiency and thus reducing fuel consumption. Previous studies show that hydraulic hybrid technology can be favourable to use in construction machinery such as wheel loaders, which often operate in repetitive drive cycles and have high transient power demands. Parallel as well as Series hybrid configurations are both found suitable for wheel loader applications as the hybrid configurations can decrease the dependency on the torque converter. This project has investigated a novel hydraulic hybrid concept which utilizes the wheel loaders auxiliary pump as a supplement to enable both Series and Parallel hybrid operation. Impact of accumulator sizes has also been investigated, for which smaller accumulator sizes resembles a hydrostatic transmission. The hybrid concept has been evaluated by developing a wheel loader simulation model and a control system based on a rule-based energy management strategy. Simulation results indicate improved energy efficiency of up to 18.80 % for the Combined hybrid. Moreover, the accumulator sizes prove to have less impact on the energy efficiency. A hybrid system with decreased accumulator sizes shows improved energy efficiency of up to 16.40 %.

Abstract According to industry estimates, monthly global mobile data traffic will surpass 30.6 exabytes by 2020 and global mobile data traffic will increase nearly eightfold between 2015 and 2020. Most of the mobile data traffic is generated by smartphones, and the total number of smartphones is expected to continue growing by 2020, which results in rapid traffic growth. In addition, the upcoming 5G networks and Internet of Things based communication are estimated to involve a large amount of network traffic. The increase in mobile data traffic and in the number of connected devices poses a challenge to network operators, service providers, and data center operators. If the transmission capacity of the network and the amount of data traffic are not in line with each other, congestion may occur and ultimately the quality of experience degrades. Mobile networks are also becoming more reliant on data centers that provide efficient computing power. However, the energy consumption of data centers has grown in recent years, which is a problem for data center operators. A traditional strategy to overcome these problems is to scale up the resources or by providing more efficient hardware. Resource over-provisioning increases operating and capital expenditures without a guarantee of increased average revenue per user. In addition, the growing complexity and dynamics of communication systems is a challenge for efficient resource management. Intelligent and resilient methods that can efficiently use existing resources by making autonomous decisions without intervention from human administrators are thus needed. The goal of this research is to implement, develop, model, and test algorithms that can enable efficient and energy-aware network resource management in autonomous communications systems. First, an energy-aware algorithm is introduced for high-performance computing data centers to reduce the energy consumption within a single data center and across a federation of data centers. For network access selection in heterogeneous wireless networks, two algorithms are proposed, a client side algorithm that tries to optimize users' quality of experience and a network side algorithm that focuses on optimizing the global resource usage of the network. Finally, for a video service, an algorithm is presented that can enhance the video content delivery in a controllable and resource-efficient way without major changes in the mobile network infrastructure
Tiivistelmä Langattoman tietoliikenteen nopean kasvun ennustetaan jatkuvan edelleen lähivuosinakin ja alan teollisuuden arvioiden mukaan matkapuhelinliikenteen määrä ylittäisi globaalisti 30,6 eksatavua vuoteen 2020 mennessä. Tämä tarkoittaisi liikennemäärän kahdeksankertaistumista ajanjaksolla 2015–2020. Älypuhelimet tuottavat suurimman osan matkapuhelinliikenteestä, ja älypuhelimien lukumäärän arvioidaan jatkavan kasvuaan vuoteen 2020 saakka, mikä johtaa nopeaan liikenteen kasvuun. Tämän lisäksi arvioidaan, että 5G verkot ja esineiden Internet tuottavat suuren määrän verkkoliikennettä. Matkapuhelinliikenteen ja laitteiden määrän kasvu tuo haasteita verkko-operaattoreille, palvelun tarjoajille, ja datakeskusoperaattoreille. Mikäli verkossa ei ole tarpeeksi siirtokapasiteettia dataliikenteen määrää varten, verkko ruuhkautuu ja lopulta palvelukokemus kärsii. Matkapuhelinverkot tulevat myös tulevaisuudessa tarvitsemaan datakeskusten laskentakapasiteettia. Datakeskusten energiankulutus on kuitenkin kasvanut viime vuosina, mikä on ongelma datakeskusoperaattoreille. Perinteinen strategia ongelmien ratkaisemiseksi on lisätä resurssien määrää tai tarjota tehokkaampaa laitteistoa. Resurssien liiallinen lisääminen kasvattaa kuitenkin sekä käyttö- että pääomakustannuksia ilman takuuta siitä, että keskimääräinen myyntitulo per käyttäjä kasvaisi. Tämän lisäksi tietoliikennejärjestelmät ovat monimutkaisia ja dynaamisia järjestelmiä, minkä vuoksi tehokas resurssienhallinta on haastavaa. Tämän vuoksi tarvitaan älykkäitä ja kestäviä metodeja, jotka pystyvät käyttämään olemassa olevia resursseja tehokkaasti tekemällä autonomisia päätöksiä ilman ylläpitäjän väliintuloa. Tämän tutkimuksen tavoitteena on toteuttaa, kehittää, mallintaa, ja testata algoritmeja, jotka mahdollistavat tehokkaan ja energiatietoisen verkkoresurssien hallinnan autonomisissa tietoliikennejärjestelmissä. Tutkimus esittää aluksi supertietokonedatakeskuksiin energiatietoisen algoritmin, jonka avulla voidaan vähentää energiankulutusta yhden datakeskuksen sisällä sekä usean eri datakeskuksen välillä. Verkkoyhteyden valintaan heterogeenisissä langattomissa verkoissa esitetään kaksi algoritmia. Ensimmäinen on käyttäjäkohtainen algoritmi, joka pyrkii optimoimaan yksittäisen käyttäjän palvelukokemusta. Toinen on verkon puolen algoritmi, joka keskittyy optimoimaan verkon kokonaisresurssien käyttöä. Lopuksi esitetään videopalvelulle algoritmi, joka parantaa videosisällön jakoa kontrolloidusti ja resurssitehokkaasti ilman että matkapuhelinverkon infrastruktuurille tarvitaan muutoksia

Recent Power On Demand approaches, realized by using speed and/or displacement variable pump units, led to a significant increase of energy efficiency on hydraulic forming presses. In this paper we follow up on this development by laying the focus on the energy management and storage design of such machinery. With a derived fluidtronical model, we compare five different topologies that supply and manage the power flow for a forming press with die cushion. Our evaluation criteria are: energy consumption, minimization of the infeed power, and qualitative costs. For a representative forming cycle, the losses occurring on each of the drivetrain components and the power electronics accessory are derived in detail. We expect that this research will lead to deeper investigation of more intelligent energy management systems that use multiple storages in an optimal way and further learn and adapt during operation.