Master of Science / Department of Electrical and Computer Engineering / Balasubramaniam Natarajan / Recently, user-cooperative MIMO (multi-input multi-output) systems have been generating significant interest due to their capacity/performance gains over SISO (single-input single-output) systems. In cooperative MIMO architectures, individual nodes with single antennas collaborate with each other to act as a MIMO unit. As a result, the individual node complexity associated with traditional MIMO implementations is alleviated. This feature is especially beneficial in sensor networks and cellular systems where individual node energy, size and cost are important constraints. Additionally, cooperative MIMO schemes provide all the benefits of traditional MIMO systems. In this work, we classify the cooperative MIMO systems into three different categories equivalent to classical MIMO, MISO and SIMO systems. For the three protocols, we quantify and compare the energy efficiency of Amplify-and-Forward (AF) and Decode-and-Forward (DF) schemes on a basic three node cooperative network. Total energy is calculated considering circuit energy as well as transmission energy. For AF and DF schemes, we set a target Symbol Error Probability (SEP) and evaluate the minimum transmission energy for achieving the target SEP. In this process,we first derive an approximation for SEP at high SNR. Then, we formulate the transmission energy calculation as an optimization problem subject to the target SEP and present the theoretical solution. The result is used to compare the total energy consumption of AF and DF for the three protocols. This is unlike most of the prior efforts that primarily focus on optimum allocation of limited total power to maximize the some peformance criterion. Since any wireless systems in order to operate have a set performance criterion, we intend to minimize the resources that is capable of achieving that.

Nearly half of Britain’s carbon dioxide emissions result from the activity of households, both within the home and from personal transport. This research examines how the carbon dioxide emissions of households can be reduced, particularly through the calculation of carbon footprints and testing the public’s reaction to the concept of personal carbon allowances (PCAs). Two data collection stages were used - a postal survey providing quantitative data, followed by semi-structured interviews producing mainly qualitative data. The research was carried out in a largely rural district which is run by a council noted for its work on sustainable energy, Newark and Sherwood. The survey looked at PCAs as well as a variety of contemporary issues that might influence household footprints such as energy efficiency grants and information, as well as relationships with gas and electricity suppliers. Each interview involved the calculation of a household carbon footprint, the identification of measures to reduce it, and the gathering of attitudes about personal carbon allowances, in order to identify challenges and opportunities with respect to reducing household carbon emissions. Support for PCAs was higher than anticipated, and tended to be associated with those who were prepared to use public transport or cycle more, or were supportive of renewable energy in homes. Interviewees had much to say about individual carbon reducing measures. Opposition was associated with those who envisaged that they would be unlikely to sell carbon units. Regarding personal transport, long commutes were common, and the cost of public transport was of concern. Specific findings were made about domestic heating, insulation, lighting, refrigeration, water use, commuting, public transport, and rail as an alternative to short-haul flights. There was more interest in monetary savings than carbon savings. Recommendations about policy and regarding further research are made.

As the wireless communication technologies evolve and the demand of wireless services increases, spectrum scarcity becomes a bottleneck that limits the introduction of new technologies and services. Spectrum sharing between primary and secondary users has been brought up to improve spectrum efficiency. In underlay spectrum sharing, the secondary user transmits simultaneously with the primary user, under the constraint that the interference induced at the primary receiver is below a certain threshold, or a certain primary rate requirement has to be satisfied. Specifically, in this thesis, the coexistence of a multiple-input single-output (MISO) primary link and a MISO/multiple-input multiple-output (MIMO) secondary link is studied. The primary transmitter employs maximum ratio transmission (MRT), and single-user decoding is deployed at the primary receiver. Three scenarios are investigated, in terms of the interference from the primary transmitter to the secondary receiver, namely, weak interference, strong interference and very strong interference, or equivalently three ranges of primary rate requirement. Rate splitting and successive decoding are deployed at the secondary transmitter and receiver, respectively, when it is feasible, and otherwise single-user decoding is deployed at the secondary receiver. For each scenario, optimal beamforming/precoding and power allocation at the secondary transmitter is derived, to maximize the achievable secondary rate while satisfying the primary rate requirement and the secondary power constraint. Numerical results show that rate splitting at the secondary transmitter and successive decoding at the secondary receiver does significantly increase the achievable secondary rate if feasible, compared with single-user decoding at the secondary receiver. In overlay spectrum sharing, different from underlay spectrum sharing, the secondary transmitter can utilize the knowledge of the primary message, which is acquired non-causally (i.e., known in advance before transmission) or causally (i.e., acquired in the first phase of a two-phase transmission), to help transmit the primary message besides its own message. Specifically, the coexistence of a MISO primary link and a MISO/MIMO secondary link is studied. When the secondary transmitter has non-causal knowledge of the primary message, dirty-paper coding (DPC) can be deployed at the secondary transmitter to precancel the interference (when decoding the secondary message at the secondary receiver), due to the transmission of the primary message from both transmitters. Alternatively, due to the high implementation complexity of DPC, linear precoding can be deployed at the secondary transmitter. In both cases, the primary transmitter employs MRT, and single-user decoding is deployed at the primary receiver; optimal beamforming/precoding and power allocation at the secondary transmitter is obtained, to maximize the achievable secondary rate while satisfying the primary rate requirement and the secondary power constraint. Numerical results show that with non-causal knowledge of the primary message and the deployment of DPC at the secondary transmitter, overlay spectrum sharing can achieve a significantly higher secondary rate than underlay spectrum sharing, while rate loss occurs with the deployment of linear precoding instead of DPC at the secondary transmitter. When the secondary transmitter does not have non-causal knowledge of the primary message, and still wants to help with the primary transmission in return for the access to the spectrum, it can relay the primary message in an amplify-and-forward (AF) or a decode-and-forward (DF) way in a two-phase transmission, while transmitting its own message. The primary link adapts its transmission strategy and cooperates with the secondary link to fulfill its rate requirement. To maximize the achievable secondary rate while satisfying the primary rate requirement and the primary and secondary power constraints, in the case of AF cooperative spectrum sharing, optimal relaying matrix and beamforming vector at the secondary transmitter is obtained; in the case of DF cooperative spectrum sharing, a set of parameters are optimized, including time duration of the two phases, primary transmission strategies in the two phases and secondary transmission strategy in the second phase. Numerical results show that with the cooperation from the secondary link, the primary link can avoid outage effectively, especially when the number of antennas at the secondary transceiver is large, while the secondary link can achieve a significant rate. Power is another precious resource besides spectrum. Instead of spectrum efficiency, energy-efficient spectrum sharing focuses on the energy efficiency (EE) optimization of the secondary transmission. The EE of the secondary transmission is defined as the ratio of the achievable secondary rate and the secondary power consumption, which includes both the transmit power and the circuit power at the secondary transmitter. For simplicity, the circuit power is modeled as a constant. Specifically, the EE of a MIMO secondary link in underlay spectrum sharing is studied. Three transmission strategies are introduced based on the primary rate requirement and the channel conditions. Rate splitting and successive decoding are deployed at the secondary transmitter and receiver, respectively, when it is feasible, and otherwise single-user decoding is deployed at the secondary receiver. For each case, optimal transmit covariance matrices at the secondary transmitter are obtained, to maximize the EE of the secondary transmission while satisfying the primary rate requirement and the secondary power constraint. Based on this, an energy-efficient resource allocation algorithm is proposed. Numerical results show that MIMO underlay spectrum sharing with EE optimization can achieve a significantly higher EE compared with MIMO underlay spectrum sharing with rate optimization, at certain SNRs and with certain circuit power, at the cost of the achievable secondary rate, while saving the transmit power. With rate splitting at the secondary transmitter and successive decoding at the secondary receiver if feasible, a significantly higher EE can be achieved compared with the case when only single-user decoding is deployed at the secondary receiver. Moreover, the EE of a MIMO secondary link in overlay spectrum sharing is studied, where the secondary transmitter has non-causal knowledge of the primary message and employs DPC to obtain an interference-free secondary link. Energy-efficient precoding and power allocation is obtained to maximize the EE of the secondary transmission while satisfying the primary rate requirement and the secondary power constraint. Numerical results show that MIMO overlay spectrum sharing with EE optimization can achieve a significantly higher EE compared with MIMO overlay spectrum sharing with rate optimization, at certain SNRs and with certain circuit power, at the cost of the achievable secondary rate, while saving the transmit power. MIMO overlay spectrum sharing with EE optimization can achieve a higher EE compared with MIMO underlay spectrum sharing with EE optimization. / Aufgrund der rasanten Entwicklung im Bereich der drahtlosen Kommunikation und der ständig steigenden Nachfrage nach mobilen Anwendungen ist die Knappheit von Frequenzbändern ein entscheidender Engpass, der die Einführung neuer Funktechnologien behindert. Die gemeinsame Benutzung von Frequenzen (Spektrum-Sharing) durch primäre und sekundäre Nutzer ist eine Möglichkeit, die Effizienz bei der Verwendung des Spektrums zu verbessern. Bei der Methode des Underlay-Spektrum-Sharing sendet der sekundäre Nutzer zeitgleich mit dem primären Nutzer unter der Einschränkung, dass für den primären Nutzer die erzeugte Interferenz unterhalb eines Schwellwertes liegt oder gewisse Anforderungen an die Datenrate erfüllt werden. In diesem Zusammenhang wird in der Arbeit insbesondere die Koexistenz von Mehrantennensystemen untersucht. Dabei wird für die primäre Funkverbindung der Fall mit mehreren Sendeantennen und einer Empfangsantenne (MISO) angenommen. Für die sekundäre Funkverbindung werden mehrere Sendeantennen und sowohl eine als auch mehrere Empfangsantennen (MISO/MIMO) betrachtet. Der primäre Sender verwendet Maximum-Ratio-Transmission (MRT) und der primäre Empfänger Einzelnutzerdecodierung. Für den sekundären Nutzer werden außerdem am Sender eine Datenratenaufteilung (rate splitting) und am Empfänger entweder eine sukzessive Decodierung – sofern sinnvoll – oder andernfalls eine Einzelnutzerdecodierung verwendet. Im Unterschied zur Methode des Underlay-Spektrum-Sharing kann der sekundäre Nutzer beim Verfahren des Overlay-Spektrum-Sharing die Kenntnis über die Nachrichten des primären Nutzers einsetzen, um die Übertragung sowohl der eigenen als auch der primären Nachrichten zu unterstützen. Das Wissen über die Nachrichten erhält er entweder nicht-kausal, d.h. vor der Übertragung, oder kausal, d.h. während der ersten Phase einer zweistufigen Übertragung. In der Arbeit wird speziell die Koexistenz von primären MISO-Funkverbindungen und sekundären MISO/MIMO-Funkverbindungen untersucht. Bei nicht-kausaler Kenntnis über die primären Nachrichten kann der sekundäre Sender beispielsweise das Verfahren der Dirty-Paper-Codierung (DPC) verwenden, welches es ermöglicht, die Interferenz durch die primären Nachrichten bei der Decodierung der sekundären Nachrichten am sekundären Empfänger aufzuheben. Da die Implementierung der DPC mit einer hohen Komplexität verbunden ist, kommt als Alternative auch eine lineare Vorcodierung zum Einsatz. In beiden Fällen verwendet der primäre Transmitter MRT und der primäre Empfänger Einzelnutzerdecodierung. Besitzt der sekundäre Nutzer keine nicht-kausale Kenntnis über die primären Nachrichten, so kann er als Gegenleistung für die Mitbenutzung des Spektrums dennoch die Übertragung der primären Nachrichten unterstützen. Hierfür leitet er die primären Nachrichten mit Hilfe der Amplify-And-Forward-Methode oder der Decode-And-Forward-Methode in einer zweitstufigen Übertragung weiter, währenddessen er seine eigenen Nachrichten sendet. Der primäre Nutzer passt seine Sendestrategie entsprechend an und kooperiert mit dem sekundären Nutzer, um die Anforderungen an die Datenrate zu erfüllen. Nicht nur das Spektrum sondern auch die Sendeleistung ist eine wichtige Ressource. Daher wird zusätzlich zur Effizienz bei der Verwendung des Spektrums auch die Energieeffizienz (EE) einer sekundären MIMO-Funkverbindung für das Underlay-Spektrum-Sharing-Verfahren analysiert. Wie zuvor wird für den sekundären Nutzer am Sender eine Datenratenaufteilung (rate splitting) und am Empfänger entweder eine sukzessive Decodierung oder eine Einzelnutzerdecodierung betrachtet. Weiterhin wird die EE einer sekundären MIMO-Funkverbindung für das Overlay-Spektrum-Sharing-Verfahren untersucht. Dabei nutzt der sekundäre Nutzer die nicht-kausale Kenntnis über die primären Nachrichten aus, um mittels DPC eine interferenzfreie sekundäre Funkverbindung zu erhalten.

I detta arbete studeras vilka möjligheter det finns för en av 3D hus kunders hus att klara kraven för passiv- eller minienergihus. Baserat på ett projekterat hus studeras hur olika konstruktioner och produktval påverkar husets möjlighet att uppfylla kraven. Trots att samtliga konstruktionsalternativ påstods vara anpassade för energisnåla hus visar vår undersökning att transmissionsförlusterna varierade mycket mellan de olika lösningarna. Även vilka garantier de olika företagen kunde ge gällande lufttäta konstruktioner varierade stort.De områdena som särskilt studeras i detta arbete är energiförluster genom en bostads klimatskal beroende av olika konstruktioner av väggarna, samt vilka fönster och dörrar som är lämpliga.Vår studie visar att utformningen av huset som studerats kommer kräva mycket höga krav på konstruktionen för att huset ska kunna nå kraven för ett passiv- eller minienergihus. Utformningen gör däremot att förlusterna varierar stort mellan de olika valen och det kan därför vara en god idé att se över vilka produkter som ska väljas inom de olika områdena. / This report considers the possibilities to build a passive house or mini-energy house within reasonable demands on manufacturers and construction firms for one of 3D House’s customers. The client has already been in contact with different manufacturers and construction firms with different demands, but with the same warranty of energy efficient materials. In this study there’s a comparison of these demands and warrants show that, even with the same stated terms of low efficient material, the transmission loss vary considerably. Especially the warrants for airtight constructions vary much.Because of the buildings shape it becomes clear that it would need very high requirement on the products and the work to meet the requirements for passive house. The shape of the house does on the other hand make sure that it's a big difference between the different products which would make it a good idea to look over the different chose.The areas there this report is in first hand how the different companies for walls because of that is an area there it's a big different between different choice and it's a big part of the climate shield. It will also have a look over what kind of windows and doors that exist that meet both the requirements for passive house and the costumer.

Magnetic shape memory alloys are active materials which deform under the application of a magnetic field or an external stress. Due to their internal friction, recognizable from the strain-stress hysteresis, this new material technology allows the design of multistable actuators. This paper describes and characterizes an innovative airflow control valve whose aperture is proportional to the deformation of the active material and thus controllable by the input voltage. The multistability of the material is partially exploited within an airflow control loop to reduce the energy losses of the valve when a specific airflow value must be hold.

Thesis (MCom)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Worldwide, energy has been, and continues to be, key to economic development. However, the current global consensus is that energy-related carbon dioxide emissions would, at current rates, put the world onto a potentially catastrophic trajectory which could lead to global warming of 5 degree Celsius or more compared to pre-industrial times. There is a critical need for a low-carbon development or a move away from conventional fossil fuels energy sources. This study explores impacts of policies that South Africa developed in order to champion sustainable energy strategies based on energy efficiency and non-conventional energy sources, including renewable energy. The mining sector, because of its energy-intensive nature, was chosen. In order to achieve this objective three approaches were carried out: (i) a critical review of literature on energy efficiency (EE) and renewable energy (RE) ; (ii) two case-studies that demonstrate the impacts of the policies; and (iii) action research on a sample of mines using survey questionnaire and interviewing. The research results show that the need to have security in energy and the need to be competitive and grow revenue are significant in deciding to carry out EE and RE initiatives in the mining sector. The results also show that safety followed by production are the priorities and are accompanied by a range of other demands, such as cost reduction and legislative requirements. It is, therefore, within this context that EE and RE initiative will always be carried out in the mining sector. The research concludes that, under the current market framework, South African EE and RE policies are not as effective as hoped they would be. The research, therefore, recommends that a percentage of the mines’ revenue could be dedicated to EE and RE initiatives. In addition, South Africa needs to come up with a new type of productive endeavour that would lead to less extractive industries, including mines. / AFRIKAANSE OPSOMMING: Energie is, was en sal wereldwyd altyd die sleutel wees tot ekonomiese ontwikkeling. Nieteenstaande, word dit wereldwyd aanvaar dat die huidige energie opwekking se koolstofdioksied vrystelling moontlik kan lei tot aardverwarming van 5 grade Celsius of meer wanneer vergelyk met word met pre-industriële tye. Daar is ‘n kritiese behoefte aan lae koolstofdioksied vrystelling ontwikkelings of ‘n beperking van konvensionele fossielbrandstof energiebronne. Hierdie studie analiseer die impak van die Suid Afrikaanse beleid wat ontwikkel is om volhoubare energie te bevorder wat effektief en onkonvensioneel is, insluitend hernubare energie. Die mynsektor, as ‘n groot verbruiker van energie, vorm die kern van die studie. Die studie is voltooi in drie fases naamlik: (1) kritiese oorsig van die literatuur oor energiedoeltreffendheid (EE) en hernubare energie (RE); (2) twee gevallestudies wat die impak van die beleid bevestig; en (3) praktiese navorsing deur middel van vraelyste en persoonlike onderhoude met seker myne. Die navorsing bevestig dat die behoefte aan bestendige energie teen kompeterende pryse wat die mynsektor in staat stel om inkomste te groei ,‘n beduidende invloed het op die besluit om EE of RE inisiatiewe te onderneem. Die resultate bevestig verder dat beroepsveiligheid en produksie uitsette die eerste prioriteite vir die myne is. Dit word verder beinvloed deur kostebesparings en wetlike vereistes. Enige EE en RE inisiatiewe wat onderneem word sal in hierdie konteks plaasvind. Die navorsing kom tot die slotsom dat, onder huidige marktoestande, Suid Afrika se EE en RE beleid nie so effektief is as waarop daar gehoop is nie. Die navorsing beveel derhalwe aan dat ‘n persentasie van myne se inkomste geoormerk moet word vir EE en RE inisiatiewe. Verder meer , Suid Afrika moet strewe na tipes produksie wat minder natuurlike grondstowwe onttrek, insluitend die myne.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Energy efficiency and the move to renewable energy resources are of vital importance in growing profitable and sustainable economies. In recent years, greater emphasis has been placed on institutions, companies and individuals to reduce their electrical energy demand through energy management. In an attempt to reduce the demand, the electrical power utility in South Africa, Eskom, has introduced Demand Side Management programs and substantial increases in electricity tariffs. In addition to these, tax incentives have been offered to help off-set the capital costs associated with the investments made in replacing old electrical equipment with new electrically efficient equipment. Thus the need for accurate Measurement and Verification of electrical energy demand reduction, to substantiate fiscal claims, has become imperative. The main purpose of Measurement and Verification is to investigate the actual monetary performance of an energy savings project. Energy savings assessments, based on purely deterministic baseline demand, do not adequately represent the statistical nature of the savings impacts of many practical load systems, as disclosed in a reporting period. This thesis presents the development of a generic probabilistic methodology to determine the demand profiles of preand post-Energy Conservation Measures (ECMs) for practical load systems. The difference between the simulated demand of the pre- and post-ECMs for a particular set of variables represent the electrical demand impact. The electrical demand of the pre- and post-ECMs is defined in terms of Probability Density Functions, and derived using a multivariate kernel density estimation algorithm. The approach is tested using a simulation model of a waterheating geyser implemented in MATLAB. Three different ECMs are simulated using the geyser model and demand density estimation. The results of the demand impacts of the ECMs are presented and evaluated. With regards to possible future research this methodology could be applied to the evaluation of the demand impacts of heat pump technologies and solar water heaters. / AFRIKAANSE OPSOMMING: en die skuif na hernubare energiebronne is van deurslaggewende belang vir die ontwikkeling van winsgewende en volhoubare ekonomieë. Onlangs is meer klem geplaas op instansies, maatskappye en individue om hul aanvraag na energie te verminder met behulp van energiebestuur. In ‘n poging om die aanvraag te verlaag, het Eskom, Suid-Afrika se elektrisiteitsverskaffer, aansienlike elektrisiteitstariefverhogings ingelyf en Aanvraagbestuursprogramme van stapel gestuur. Bykomend hiertoe is belastingaansporings ook aangebied, waarteen kapitale kostes, geassosieer met die vervanging van ou elektriese toerusting met nuwe elektries doeltreffende toerusting, afgeset kan word. Derhalwe het die behoefte aan akkurate Meting en Verifikasie van elektriese energie aanvraagvermindering, om finansiële eise te staaf, noodsaaklik geword. Die hoofdoel van Meting en Verifikasie is om die werklike finansiële prestasie van energiebesparingsprojek te ondersoek soos bekend gemaak word tydens ’n verslagdoeningstydperk. Energiebesparingassesserings wat slegs gebaseer word op die suiwer deterministiese basislyn aanvraag na elektrisiteit, verteenwoordig nie die werklike statistiese aard van die besparingsimpakte van baie praktiese lasstelsels nie. Hierdie tesis stel die ontwikkeling van generiese waarskynlikheids-metodologie voor, om die voor- en na- Energiebesparings-maatreëls se aanvraagprofiele vir sulke praktiese lasstelsels, vas te stel. Die verskil tussen die gesimuleerde aanvraag van die voor- en na- Energiebesparings-maatreëls vir spesifieke stel veranderlikes verteenwoordig die elektriese aanvraag impak. Die voor- en na- Energiebesparings-maatreëls van die energieverbruik profieldata word gedefinieer in terme van Waarskynlikheidsdigtheidsfunksies en afgelei deur gebruik te maak van meerveranderlike kerndigtheidafskattingsalgoritme. Die benadering is getoets deur gebruik te maak van simuleringsmodel van warmwaterstelsel geïmplimenteer in MATLAB. Drie verskillende voor- en na- Energiebesparings-maatreëls is gesimuleer met behulp van die warmwaterstelselmodel en aanvraag digtheidafskatting. Die resultate van die elektriese aanvraag impakte van die voor- en na- Energiebesparings-maatreëls word vervolgens bespreek en geëvalueer. Met betrekking tot moontlike toekomstige navorsing kan hierdie metodologie toegepas word om die aanvraag impakte van hittepomp- en sonwaterverwarmingstegnologieë te evalueer.

<p>With the increasing capacity of today's integrated circuits, a number ofheterogeneous  system-on-chip (SoC)  architectures  in embedded  systemshave been proposed. In order to achieve energy and design cost efficientstreaming applications  on these  systems, new design  space explorationframeworks  and  performance  analysis  approaches are  required.   Thisthesis  considers three state-of-the-art  SoCs architectures,  i.e., themulti-processor SoCs (MPSoCs)  with network-on-chip (NoC) communication,the hybrid CPU/FPGA architectures, and the run-time reconfigurable (RTR)FPGAs.  The main topic of the  author?s research is to model and capturethe  application  scheduling,  architecture  customization,  and  bufferdimensioning  problems, according to  the real-time  requirement.  Sincethese  problems  are NP-complete,  heuristic  algorithms and  constraintprogramming solver are used to compute a solution.For  NoC  communication  based  MPSoCs,  an  approach  to  optimize  thereal-time    streaming    applications    with   customized    processorvoltage-frequency levels and memory  sizes is presented. A multi-clockedsynchronous  model  of  computation   (MoC)  framework  is  proposed  inheterogeneous  timing analysis and  energy estimation.   Using heuristicsearching  (i.e., greedy  and  taboo search),  the  experiments show  anenergy reduction (up to 21%)  without any loss in application throughputcompared with an ad-hoc approach.On hybrid CPU/FPGA architectures,  the buffer minimization scheduling ofreal-time streaming  applications is addressed.  Based  on event models,the  problem  has  been  formalized  decoratively  as  constraint  basescheduling,  and  solved  by  public domain  constraint  solver  Gecode.Compared  with  traditional  PAPS  method,  the  proposed  method  needssignificantly smaller  buffers (2.4%  of PAPS in  the best  case), whilehigh throughput guarantees can still be achieved.Furthermore, a  novel compile-time analysis approach  based on iterativetiming  phases is  proposed  for run-time  reconfigurations in  adaptivereal-time   streaming   applications  on   RTR   FPGAs.   Finally,   thereconfigurations analysis and design trade-offs analysis capabilities ofthe proposed  framework have been  exemplified with experiments  on bothexample and industrial applications.</p> / Andres

<p>The present environmental concerns and the rising human requirement for solutions with better comfort and lower costs have resulted in an increased awareness for the energy use in the built environment. Technical advances in building structural systems and materials, heating and other comfort-providing systems and controlling strategies all lead to the integration of building technology with the function of buildings and the aesthetics. Therefore, in the process of improving the performance of energy systems and increasing the energy efficiency, integrated system approaches are of high importance. Performing the necessary energy analysis before any construction-installation occurs can help designers and decision makers reach guided solutions. Hence, a broad range of calculation tools for evaluating the operation of energy systems and the controls in buildings have been developed the latest years with different levels of complexity and angles of focus.</p><p>However, research and development regarding holistic energy system designs and techniques are in their infancy. The standard tactic has been to isolate system parts, study them as stand-alone sub-systems and focus on optimising components or processes of a complex function. In the present study, it is demonstrated the necessity for uniting energy engineers, architects, installers and technicians regarding decision making upon the energy use for heating, ventilation and air-conditioning (HVAC) in the built environment. Systems approach has been employed for studying the research issue that is presented in the current thesis. An extended part of this treatise has been devoted to systems thinking in practice.</p><p>The thesis demonstrates systematic methods of modelling and analysing certain, integrated, domestic, HVAC applications. The reference system boundaries enclose the building as a construction and as a dynamic function, a comfort-providing system based on a heat pump, a low-temperature hydronic heat distribution system and controls in a residential application. Obviously, these are not the only components met in a hydronic heating system. Numerous pieces of equipment, as piping, circulating pumps, expansion tanks, zone valves, relief valves and other essential elements are needed to make a safe and functional heating system. However, this study focuses on the analysis of the chosen reference system. Several models have been developed in the computational tools of TRNSYS and EES. These tools have been employed because they allow co-solving, hence the integrated system as well as the interaction between the different parts of the system can be studied.</p><p>The foremost result of this study is that approaching the system as a whole provides a better picture of the operation of every system component and the interaction between them. Explanations are given for the parameters that have a significant impact on the system’s performance. The thesis shows the importance of factors that are not easy to predict, as well as the difference in the building’s behaviour under fast changing thermal loads when the incorporated thermal mass is altered. Finally, implementing sophisticated controls for reducing the energy costs without compromising thermal comfort is vital.</p>

<p>Energy Director is a control and measuring system for energy consumption and is part of the product portfolio of E.ON AG for more efficient use of energy, offered to business customers. As of today, the system has only one parameter of control, namely power, and the objective of this essay has been to investigate whether other ones could be added. The emphasis is on the environmental perspective, which is why carbon dioxide has served as an example for this parameter in question.</p><p>Parallel with the study of Energy Director electricity on the margin, calculations of carbon dioxide equivalents and also the Swedish trade of electricity have all been highlighted. Results indicate that when reductions in energy are made it is endorsed to omit from electricity on the margin rather than some mean distributed electricity, under certain conditions, and in addition the calculations of the reductions should be modified regarding the efficiency of the power stations fuelled by lignite and bituminous coal. Sweden practices trade with the Nordic countries as well as Poland and Germany. Import and export represents essential factors in the discussion of electricity on the margin but they can nonetheless today be included in calculations concerning savings in emission of carbon dioxide.</p><p>The development of Energy Director is suggested to follow a model that includes the total emissions of carbon dioxide at each installation. Contributions are descended from local sources at the site, which are continuously measured, and from the energy that is obtained, where the equivalent amount of carbon dioxide has to be theoretically estimated. The total carbon dioxide limit control is then accomplished by means of controlling the obtained energy.</p> / <p>EnergiDirigent är ett styr- och mätsystem som ingår i E.ON:s produktsortiment för effektivare energianvändning. I dagsläget har systemet en styrparameter, uttagen effekt, och syftet med detta arbete har varit att undersöka om ytterligare styrparametrar kan infogas. Fokus för arbetet har varit att undersöka vilken potential EnergiDirigent har att bli miljövänlig. Styrparameter som tjänat som exempel för utredning har varit koldioxid.</p><p>Marginalel, det svenska elutbytet samt beräkning av koldioxidekvivalenter har behandlats parallellt med arbetet med EnergiDirigent. Arbetsgången har varit teoretisk med litteraturstudier, studiebesök och intervjuer. Resultat visar att vid en miljövärdering av el är det befogat att utgå ifrån marginalel vid besparingar, dock under vissa villkor, och att beräkningarna av besparingarna bör modifieras genom att verkningsgraden för kolkraftverk revideras. Sverige bedriver mycket handel med Norden samt Polen och Tyskland varför de har inkluderats i handelssystemet. Import och export är viktiga faktorer i behandling av marginalel men resurser saknas idag för att implementera faktorerna på ett adekvat sätt i besparingsuträkningar.</p><p>Utvecklingen av EnergiDirigent bör följa en modell som inkluderar det totala utsläppet av koldioxid vid varje installation. Bidrag till det totala utsläppet kommer ifrån lokala källor hos installationen, som hela tiden mäts, samt från den mängd energi som införskaffas, där motsvarande mängd koldioxid uppskattas teoretiskt. En styrgräns sätts på de totala utsläppen och följs sedan genom styrning på den inkommande energin.</p>