Thesis (PhD)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The importance of waste management is growing rapidly for several reasons. These reasons include the escalating cost of wastewater treatment and cleaning chemicals, an emerging trend of onerous regulatory regime regarding e uent disposal from governments, rising public awareness on the adverse e ects of industrial waste as well as drastic reduc- tion in water resources in the winegrowing regions. In addition, owing to the large energy demand for refrigeration purposes for high quality wine production and rapidly increasing energy costs, the challenges of energy management in the wine industry were also inves- tigated. In order to address these challenges adequately, the solutions were derived via the integration of two disciplines: environmental science (waste and energy management) and computer science (applications of arti cial intelligence). Therefore, the ndings re- ported from this study seek to advance knowledge through the construction of decision support systems for waste and energy management in circumstances where conventional mathematical formalisms are inadequate. In that sense, the dissertation constitutes in- terdisciplinary research on the application of integrated arti cial intelligence technologies (expert systems and fuzzy logic) in designing and developing decision tools for waste and energy management in the wine industry. The dissertation rst presents the domain of interest, where the scope and breadth of the problems it addresses are clearly de ned. Critical examination of the domain data- bases revealed that data, information, and knowledge for waste and energy management in the wine industry are generally incomplete and lack structure overall. Owing to these characteristics, a hybrid system approach was proposed for the development of decision support systems based on fuzzy logic. The integrated decision support systems were de- veloped based on an object-oriented architecture. This approach facilitated the exible design required for waste and energy management-related complex problem-solving. To illustrate the applicability of the o -line decision tools developed, several case stud- ies mirroring on actual industrial practices were considered. These systems were found to be robust and yielded results that were in accordance with actual industrial practices inthe wine industry. Furthermore, they provided intelligent suggestions in scenarios where there was minimal information, and under certain instances they o ered feasible sugges- tions in circumstances where a human novice could have problems in making the right decisions. / AFRIKAANSE OPSOMMING: Die belangrikheid van afvalbestuur neem om verskeie redes vinnig toe. Die redes sluit in die eskalerende koste van afvalwaterbehandeling en skoonmaakmiddels, streng regula- toriese vereistes van regeringskant met betrekking tot die verwydering van uitvloeisels, toenemende openbare bewustheid van die nadelinge e ekte van nywerheidsafval, sowel as die drastiese afname in waterbronne in wynproduserende omgewings. Daarby, a.g.v. die groot energieverbruik wat deur die verkoeling van hokwaliteitwyn vereis word en die snelgroeiende energiekoste, is die uitdagings van energiebestuur in die wynbedryf ook on- dersoek. Ten einde die uitdagings die hoof te kon bied, is oplossings gevind deur die integrasie van twee disciplines: omgewingswetenskap (afval- en energiebestuur) en rekenaarweten- skap (toepassings van kunsmatige intelligensie). Gevolglik is daar deur die bevindinge van die studie gepoog om kennis te bevorder deur die konstruksie van besluitnemingson- dersteuningstelsels vir afval- en energiebestuur onder omstandighede waar konvensionele wiskundige algoritmes ontoereikend sou wees. In die opsig verteenwoordig die proefskrif interdissiplinre navorsing in die toepassing van gentegreerde kunsmatige intelligensieteg- nologie (kundige stelsels en wasige logika) in die ontwerp en ontwikkeling van besluitne- mingshulpmiddels vir afval- en energiebestuur in die wynindustrie. Die proefskrif baken eers die probleemgebied af, waarna die bestek en omvang van die probleme waarop die werk gemik is duidelik gede nieer word. Kritiese ondersoek van die databasisse in die domein het getoon dat die data, informasie en kennis oor afval- en energiebestuur in die wynbedryf in die algemeen onvolledig en gebrekkig gestruktureer is. A.g.v. di eienskappe, is 'n hibriede stelselbeandering voorgestel vir die ontwikkeling van besluitnemingstelsels gegrond op wasige logika. Die gentegreerde besluitnemingsonders- teuningstelsels is ontwikkel op 'n objek-georinteerde argitektuur. Die benadering het die daarstelling van 'n buigsame ontwerp wat benodig word vir komplekse probleemoplossing in afval- en energiebestuur vergemaklik. Om die toepaslikheid van die a ynige besluitnemingshulpmiddels wat ontwerp is, te illustreer, is verskeie gevallestudies wat werklike industrile praktyk uitbeeld beskou. Diestelsels was robuust en het resultate gelewer wat in ooreenstemming was met werklike industrile praktyke in die wynnywerheid. Die kundige stelsels het verder intelligente voorstelle gemaak in scenarios waar daar minimale informasie beskikbaar was, en onder sekere omstandighede het hulle realistiese oplossings voorgestel waar 'n onkundige persoon probleme sou gehad he tom die regte besluite te kon neem.

M. Tech. Business Administration / The question of energy supply and reliable sources of energy is a topical issue in most developing countries, as the reliability of energy supply has a significant impact on development. Swaziland, like most underdeveloped countries in sub-Saharan Africa, suffers from poverty and low economic activity, particularly in the rural areas. The kingdom's rural areas are characterised by low entrepreneurial activities, which may be attributed to the lack of reliable access to energy, and in particular, electricity. To reverse the scourge of stagnant economic development, Swaziland, like many other developing countries in Africa including South Africa and Zimbabwe, has introduced rural electrification programmes to improve access to energy within rural communities. Against this background, the purpose of this study, therefore, is to assess how rural electrification promotes entrepreneurship in rural areas.

Traditional research into pro-environmental behaviour change has a tendency to be focussed on either the context in which practices are enacted or the cognitive processes that lead to particular behaviours. Research is often located within individual disciplines, with policy implications defined by (often) narrow interpretations of a problem. Despite increasing recognition of the ability of behaviour change to significantly contribute to the reduction in emissions required to meet UK targets, policy is so far failing to encourage ‘normative’ low carbon practices in many areas of life. Based on theories of social practice, this thesis attempts to redress the relationship between individuals and behaviour in order to discover how energy practices are developed, maintained and reconfigured. Specifically, it develops a phenomenological approach to energy consumption by exploring how energy practices are experienced by individuals on a daily basis, based on the premise that much human behaviour is driven by individuals’ perceptions of their actions. The study highlights the importance of the meanings and associations that individuals possess in relation to their energy practices and how these are implicated by their experiences, past and present. Furthermore, it contends that practices are influenced by social interactional dynamics and normative frameworks within the home, as well as by the form and frequency of social relations external to the home. With energy consumption so closely interlocked with the practices with which individuals engage in a daily basis, this thesis suggests that policy needs to be more in tune with the everyday experiences of energy consumers. It concludes by setting out a form of policy-making that has the potential to reduce everyday energy use by being sensitive to the experiences and well-being of individuals and society.

Conventional energy sources are not only finite and depleting rapidly, but are a major source of global warming because they are key contributors of greenhouse gases to the atmosphere. Renewable energy sources are one important approach to these challenges. Distributed micro-generation energy sources are expected to increase the diversity of energy sources for the grid, but also increase the flexibility and resilience of the grid. Furthermore, it could reduce the domestic energy demand from the grid by enabling local consumption of energy generated through renewable sources. The most widely installed renewable energy generation systems in domestic environments, in UK, are based on solar power. However, there is a common recurring issue related to output intermittency of most promising renewable energy generation methods (e.g. solar and wind), resulting in a temporal energy mismatch between local energy generation and energy consumption. Current state-of-the-art technologies/solutions for tackling temporal energy mismatch rely on various types of energy storage technologies, most of which are not suitable for the domestic environments because they are designed for industrial scale application and relatively costly. As such energy storage system technologies are generally not deemed as economically viable or attractive for domestic environments. This research project seeks to tackle the temporal energy mismatch problem between local PV generated energy and domestic energy consumption without the need for dedicated energy storage systems; without affecting the householders comfort and/or imposing operational burdens on the householders. Simulation has been chosen as the major vehicle to facilitate much of the research investigation although data collated from related research projects in the UK and Jordan have been used in the research study. Solar radiation models have been established for predicting the solar radiation for days with clear-sky for any location at any time of the year. This model has achieved a correlation factor of 0.99 in relating to the experimental data-set obtained from National Energy Research Centre Amman/Jordan. Such a model is an essential component for supporting this research study, which has been employed to predict the amount of solar power that could be obtained in different locations and different day(s) of the year. A Domestic Energy Ecosystem Model (DEEM) has been established, which is comprised of two sub-models, namely “PV panels” and “domestic energy consumption” models. This model can be configured with different parameters such as power generation capacity of the photovoltaic (PV) panels and the smart domestic appliances to model different domestic environments. The DEEM model is a vital tool for supporting the test, evaluation and validation of the proposed temporal energy mismatch control strategies. A novel temporal energy mismatch control strategy has been proposed to address these issues by bringing together the concepts of load shifting and energy buffering, with the support of smart domestic appliances. The ‘What-if’ analysis approach has been adopted to facilitate the study of ‘cause-effect’ under different scenarios with the proposed temporal energy mismatch control strategy. The simulation results show that the proposed temporal energy mismatch control strategy can successfully tackle the temporal energy mismatch problem for a 3 bedroom semi-detached house with 2.5kWp PV panels installed, which can utilise local generated energy by up to 99%, and reduce the energy demand from the grid by up to 50%. Further analysis using the simulation has indicated significant socio-economic impacts to the householders and the environment could be obtained from the proposed temporal energy mismatch control strategy. It shows the proposed temporal energy mismatch control strategy could significantly reduce the annual grid energy consumption for a 3 bedrooms semi-detached house and produce significant carbon reductions.

Mjölkindustrin tillhör en av världens största industrier, och är den snabbaste växande sektorn inom jordbruksnäring. Varje år produceras cirka 800 miljoner ton mjölk världen över, varav svenskar årligen konsumerar cirka 150 kg mejeriprodukter per person. Framställningen av mejeriprodukter innefattar ett flertal processer som kräver stora mängder energi, främst i form av ånga till upphettning av mjölk och vatten samt elektricitet till kylning. Anledningen till att mjölken genomgår diverse behandlingar är framförallt för att döda skadliga bakterier och sporer men också ur kvalitetssynpunkt. För att möta de miljömässiga utmaningar vi står inför krävs att nya hållbara lösningar utvecklas och implementeras. Enligt miljöbalken ska verksamheter använda förnybara energikällor i den utsträckning det är möjligt, återvinning av värme skall nyttiggöras och det ska hushållas med såväl energi som andra resurser. Wermlands Mejeri, beläget i Värmlands Nysäter, startade sin verksamhet i september 2015. Mejeriet framställer dagligen 18 400 liter lättmjölk, mellanmjölk, standardmjölk och grädde, med målet att till augusti 2016 dubbla produktionen med samma sortiment. Syftet med del I av denna studie är att utföra en energikartläggning för att bestämma mejeriets totala energibehov samt hur behovet är fördelat på diverse processer. Energiinventeringens syfte utöver att skapa insikt i hur energianvändningen är fördelad är att ligga som grund för jämförelser med liknande anläggningar. På så vis kan en uppfattning om förbättringspotential erhållas. Vid jämförelser mellan olika anläggningar har nyckelvärdet specifik energikonsumtion, SEC, använts.  SEC definieras som använd energi dividerat med den totala produktionsvolymen och kan appliceras på en delprocess eller en hel produktionsanläggning. Analyser av energianvändning och effektiviseringspotential har utförts genom termodynamiska beräkningar, fysiska mätningar, simuleringar och ingenjörsmässiga uppskattningar. Enligt den kartläggning som gjorts förbrukar Wermlands mejerier idag 1141 MWh per år, vilket motsvarar ett SEC-värde på 0,19 kWh/liter mjölkprodukt. Vid en fördubbling av produktionen skulle energianvändningen öka till 1570 MWh per år och SEC-värdet reduceras till 0,13 kWh/l varav värmebehovet representerar 0,09 kWh/l. Två svenska referensanläggningar som använts vid jämförelser har ett totalt SEC-värde på 0,11 respektive 0,12 kWh/liter mjölkprodukt där värmebehovets SEC-värde är 0,05 respektive 0,06 kWh/l. Syftet med del två av studien är således att belysa förbättringspotential genom reducerat värmebehov och ånganvändande. Målet är att presentera åtgärder som sänker och tillgodoser energibehovet utan förbränning av fossila bränslen. Resultatet visar att bränslebehovet kan reduceras från 105 till 782 MWh/år med olika åtgärder. Bränslekostnaden utan åtgärder antas vid dubblad produktion uppgå till drygt 750 000 SEK per år. Vid utbyte till pelletspanna och med samtliga åtgärder genomförda är bränslekostnaden 250 000 SEK/år och koldioxidutsläppen reducerades med över 1000 ton/år. Totala SEC-värdet på värmesidan reduceras då från 0,09 kWh/l till 0,06 kWh/l vilket är jämförbart med de svenska referensanläggningarna. / The dairy industry is one of the world’s largest industries, and the most rapidly expanding sector of agriculture. Every year more than 800 million tons of milk is produced globally, of which the Swedish population annually consumes more than 150 kg per capita. Refinement of milk includes several processes that require large amounts of energy, mainly in the form of steam for heating of milk and electricity for cooling. The main reasons the milk has to go through these heating and cooling process is to reduce the bacterial count, rendering the product safe to drink and of a consistent quality. To meet the environmental challenges that lie ahead, it is important that sustainable solutions for the dairy industry are developed and implemented. According to the environmental code, all industries shall use renewable energy sources to the highest possible degree, recycling of heat shall be used and housekeeping of energy and other resources is of uttermost importance. Wermlands Mejeri, a dairy plant in Värmlands Nysäter, started their operations in September 2015. Today they produce about 18 400 liters of dairy product, with a product portfolio consisting of three different types of milk (0.5, 1.8, and 3 percent fat) and cream. Their goal is to expand the operation, so that the production volume will be doubled by august 2016. The commencing chapter of this report is based on a survey with the goal of defining the total energy consumption at the plant, and also to investigate how the need of energy is divided between the different processes. This survey is purposed to be compared to the energy consumption at other similar dairy plants, in order to point out if (and where) there is any potential to increase the energy efficiency. When comparing different facilities, the key indicator Specific Energy Consumption (SEC) is used. SEC is defined as the total used energy divided by the amount of product, and can be applied on specific processes as well as an entire operation. According to the analysis, Wermlands mejerier consumes 1141 MWh yearly, which corresponds to a SEC index of 0.19kWh/liter milk product. A doubling of the milk production would lead to an increase in energy use to 1570 MWh/year, and a reduction in SEC to 0.13 kWh/l of which the heating system stands for 0.09 kWh/l. The two Swedish reference factories which were used as comparison have an SEC index of 0.11 and 0.12 kWh/l milk product, of which the heating system stands for 0.05 and 0.06 kWh/l, respectively. The aim of the second part of the study is to highlight the potential for improvement by reducing the heating demand and steam usage. The goal is to suggest practice changes that reduce and meet the need for energy without burning fossil fuels. The study shows that the fuel usage can be reduced from 1050 to 782 kWh/year by different interventions. Without these interventions, the fuel cost is expected to reach over 750,000 SEK/year when doubling the production. If all interventions, including changing to pellet boiler, are implemented, the fuel cost will be 150,000 SEK/year and the carbon dioxide emissions reduced by over 1,000 tons yearly. The total SEC index of the heating system will then be reduced from 0.09 to 0.06 kWh/l, which is comparable to the Swedish reference factories.

Thesis (MBA)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: This research study explored energy efficiency and the possible implications for a South African company, the Pioneer Foods Group (Pioneer Foods). “What value could Pioneer Foods derive from an energy efficiency strategy?” is the research question posed in this study. The case study analysis revealed that Pioneer Foods recently listed on the Johannesburg Stock Exchange and therefore needed to implement an environmental management strategy as part of their carbon footprint reporting. Energy efficiency turned out to be one aspect that could have a significant impact on their carbon footprint. The most important barrier to energy efficiency identified at Pioneer Foods was found to be the lack of real-time electrical consumption information as this could result in a lack of ownership taken by mill management. Further barriers included the use of wrong information for benchmarking purposes as well as a possible misunderstanding of the different electricity tariffs shown on the electrical utility bill. Possible ways to overcome the barriers to energy efficiency at Pioneer Foods included installation of energy meters for real-time monitoring of the energy consumption, empowerment of people to ensure buy-in, as well as key performance indicators for mill managers linked to energy efficiency. It was suggested that the energy efficiency strategy be implemented in stages covering short-term, medium-term and long-term objectives. This way the implementation process would seem less intrusive to people and also give the energy efficiency team the opportunity to learn more and perhaps adjust the strategy throughout the implementation process. This research project should act as a starting point for Pioneer Foods to grow from being unconsciously incompetent to becoming consciously competent in the field of energy efficiency. The observations made throughout this study, should convince companies that energy efficiency should not just matter to high energy users. All companies should explore their own drivers for implementing energy efficiency and act on it. / AFRIKAANSE OPSOMMING: Hierdie navorsingstudie het die effektiewe gebruik van energie, en die moontlike implikasies vir ‘n Suid Afrikaanse maatskappy, die Pioneer Voedsel Groep (Pioneer Voedsel) ondersoek. “Watter waarde sou Pioneer Voedsel kon put uit ‘n energie-effektiwiteit-strategie?” is die navorsingsvraag wat in hierdie studie gestel is. Uit die analise blyk dat Pioneer Voedsel onlangs op die Johannesburgse Effektebeurs genoteer is. Daar word dus van hulle verwag om ‘n omgewingsbestuur-strategie in plek te stel as deel van hul koolstofvoetspoor-verslaggewing. Dit blyk dat energie-effektiwiteit een aspek is wat ‘n groot impak op hulle koolstofvoetspoor kan hê. Die grootste struikelblok tot energie-effektiwiteit by Pioneer Voedsel geïdentifiseer, was die tekort aan intydse elektriese verbruiksinligting. Dit kan veroorsaak dat die bestuur nie eienaarskap neem van energie-effektiwiteit nie. Verdere struikelblokke sluit in die gebruik van foutiewe inligting vir metingsdoeleindes asook ‘n moontlike gebrek aan begrip van die verskillende elektrisiteitstariewe uiteengesit op die elektrisiteitsrekening. Moontlike maniere om die struikelblokke by Pioneer Voedsel te oorkom sluit in die installasie van energiemeters vir intydse monitering van energieverbruik, bemagtiging van mense om inkoop te verseker, en sleutelprestasie-aanwysers vir bestuurders gekoppel aan energie-effektiwiteit. Dit word voorgestel dat die energie-effektiwiteit-strategie in fases geïmplementeer word om sodoende kort-, medium- en langtermyn-mikpunte te bereik. Sodoende sal die implementering van die proses minder indringend vir personeel wees. Dit gee ook die energie-effektiwiteit-span die kans om meer te leer asook die strategie aan te pas soos nodig tydens die implementeringsproses. Hierde navorsingsprojek moet dien as die vertrekpunt vir Pioneer Voedsel om te groei van onwetend onbekwaam tot wetend bekwaam in die veld van energie-effektiwiteit. Verder behoort dit maatskappye te oortuig dat energie-effektiwiteit nie net ‘n verskil maak vir hoë energie verbruikers nie, maar dat alle maatskappye hulle eie drywers vir die implementering van energie-effektiwiteit behoort te identifiseer en daarvolgens aksiestappe te neem.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

High speed serial links are critical components for addressing the growing demand for I/O bandwidth in next-generation computing applications, such as many-core systems, backplane and optical data communications. Due to continued process scaling and circuit innovations, today's CMOS serial link transceivers can achieve tens of Gb/s per pin. However, most of their reported power efficiency improves much slower than the rise of data rate. Therefore, aggregate I/O power is increasing and will exceed the power budget if the trend for more off-chip bandwidth is sustained. In this work, a system level statistical analysis of serial links is first described, and compares the link performance of Non-Return-to-Zero (2-PAM) with higher-order modulation (duobinary) signaling schemes. This method enables fast and accurate BER distribution simulation of serial link transceivers that include channel and circuit imperfections, such as finite pulse rise/fall time, duty cycle variation, and both receiver and transmitter forwarded-clock jitter. Second, in order to address link power efficiency, two test chips have been implemented. The first one describes a quad-lane, 6.4-7.2 Gb/s serial link receiver prototype using a forwarded clock architecture. A novel phase deskew scheme using injection-locked ring oscillators (ILRO) is proposed that achieves greater than one UI of phase shift for multiple clock phases, eliminating phase rotation and interpolation required in conventional architectures. Each receiver, optimized for power efficiency, consists of a low-power linear equalizer, four offset-cancelled quantizers for 1:4 demultiplexing, and an injection-locked ring oscillator coupled to a low-voltage swing, global clock distribution. Measurement results show a 6.4-7.2Gb/s data rate with BER < 10⁻¹² across 14 cm of PCB, and an 8Gb/s data rate through 4cm of PCB. Designed in a 1.2V, 90nm CMOS process, the ILRO achieves a wide tuning range from 1.6-2.6GHz. The total area of each receiver is 0.0174mm², resulting in a measured power efficiency of 0.6mW/Gb/s. Improving upon the first test chip, a second test chip for 8Gb/s forwarded clock serial link receivers exploits a low-power super-harmonic injection-locked ring oscillator for symmetric multi-phase local clock generation and deskewing. Further power reduction is achieved by designing most of the receiver circuits in the near-threshold region (0.6V supply), with the exception of only the global clock buffer, test buffers and synthesized digital test circuits at nominal 1V supply. At the architectural level, a 1:10 direct demultiplexing rate is chosen to achieve low supply operation by exploiting high-parallelism. Fabricated in 65nm CMOS technology, two receiver prototypes are integrated in this test chip, one without and the other with front-end boot-strapped S/Hs. Including the amortized power of global clock distribution, the proposed serial link receivers consume 1.3mW and 2mW respectively at 8Gb/s input data rate, achieving a power efficiency of 0.163mW/Gb/s and 0.25mW/Gb/s. Measurement results show both receivers achieve BER < 10⁻¹² across a 20-cm FR4 PCB channel. / Graduation date: 2012

The present thesis is primarily motivated by the will to provide help for decisionmaking on the overall layout of a house or a housing development in the very early stages of design from the point of view of energy efficiency and thermal comfort. This study contributes towards a deeper understanding of thermal interactions between a house and its adjacent enclosed open spaces. It addresses the contribution of the yard design, i.e. placement, size and type towards the development of a comfortable microclimate within the yard itself, as well as the reduction of total energy demands of the house for mechanical heating and cooling. The focus is put on the applicability of the results and findings are expressed in form of a decision-making aid. This research also makes empirical and analytical assessments on the validity of some existing methods and tools that are used for understanding the nature of microclimates in small scales and proposes methods for their improvement, particularly when used in conjunction with standard tools for the assessment of indoor climates. These methods are also demonstrated through an exemplary application in an archetypal setting and the results of the exemplary case are analysed to reach a decision on the most advisable design layouts for the buildings in the example. As a result, this work emphasises on the importance of private outdoor spaces and how their careful design can benefit occupiers, investors and the environment.