Thesis (MScIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: In the literature study energy efficiency is discussed in general, as well as certain critical areas of importance to this study. In addition, measuring and monitoring equipment, and energy inefficiencies in steam and refrigeration systems are reviewed briefly. In the energy analysis, an energy audit strategy is discussed in general. A walkthrough audit of the plant was conducted with specific focus on visible losses in the steam, refrigeration and production line systems. An energy analysis, as discussed in Chapter 3, indicates the main energy consumers, with steam being the biggest consumer of energy. The main consumers of refrigeration energy are the cold stores, flow freezer and blast freezer. Energy consumption in the cold stores can be minimised mechanically, while refrigeration energy of the flow freezer and blast freezer can be minimised through the modification of production activity. The main consumers of steam at the processing plant are the dryers, oil fryer, blanchers and steam peeler. Improved energy savings at the dryers can be obtained through optimisation of moisture and heat transfer mechanisms, while the energy of the blanchers and steam peeler can be combined by means of heat exchangers. The transfer of waste energy by means of a finned-tube heat exchanger from the steam peeler to the blanchers was investigated. The newly installed coal boiler shows capacity for improving the quality of steam, as well as efficiency, by incorporating an economiser and separator for improving steam quality, automatic TDS control and blow-down heat recovery. The product life cycle is discussed considering future automation that could lead to energy and labour savings. Lastly the utilisation of product waste as a future research subject is discussed. A confidentiality agreement was entered into with Oceana. / AFRIKAANSE OPSOMMING: In die literatuurstudie word energie-effektiwiteit oor die algemeen bespreek, asook sekere kritieke areas wat vir die ondersoek van belang is. Hierbenewens word meettoerusting vlugtig bespreek, asook energie-oneffektiwiteite in die verkoeling- en stoomstelsels. In die energie-ontleding word ’n energie-ouditstrategie in die breë bespreek. ’n Deurstapoudit van die aanleg is uitgevoer met spesifieke fokus op sigbare verliese in die verkoelingstelsel, stoomstelsel en produksielyn. Die samestelling van energieverbruik in die aanleg word uiteengesit in Hoofstuk 3, waar dan ook aangedui word dat stoom die grootste energieverbruiker is. Die hoofverbruikers van verkoelingsenergie is die koelkamers, die deurvloei-vrieskamer en die blitsvrieskamer. By die koelkamers kan verliese meganies geminimeer word, terwyl veranderinge aan produksie-aktiwiteite energieverbruik by die deurvloei-vrieskamer en die blitsvrieskamer kan verlaag. Die hoofverbruikers van stoom by die verwerkingsaanleg is die droërs, oliebraaier, blansjeerders en stoomskiller. Energie-effektiwiteit by die droërs kan verhoog word deur vog- en warmte-oordrag optimaal te laat plaasvind deur korrekte instandhoudingsprosedures. Energieverbruik by die stoomskiller en blansjeerders kan deur middel van warmteruilers gekombineer word. ’n Ondersoek na die energie-integrasie van die stoomskiller en die blansjeerders is dan ook uitgevoer. Die pas geïnstalleerde steenkoolketel toon ruimte vir die verhoging van energie-effektiwiteit deur die daarstel van ’n ekonomiseerder – ’n skeier wat die gehalte van die stoom verbeter, outomatiese TDS-beheer en afblaasherwinning. Die produk se lewensiklus word bespreek ten einde toekomstige outomatisering te motiveer in terme van energie- en arbeideffektiwiteit, asook die uitskakeling van onnodige blootstelling van die produk aan omgewingstemperature. Laastens word die herwinning van afvalstowwe as ’n toekomstige navorsingsprojek bespreek. ’n Vertroulikheidsooreenkoms is met Oceana gesluit en word eerbiedig.

Thesis (MBA)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Due to rising energy costs, there is a growing need to reduce energy consumption (limiting greenhouse gas emissions) and reduce electricity demand (as supply capacity is not keeping up with the increased demand), and their resulting financial impact. This research study investigated the management and reporting of energy consumption at the Stellenbosch University (SU). When considering the three pillars of sustainability (economic, social and environment), the impact of energy usage is high on both financial and natural resources. The research focused on the impact of regular feedback encouraging behavioural change to enable saving of the energy resource, namely electricity, that is becoming more scarce and costly. The interview results correlated with various studies proving that the context and frequency of updated energy consumption information influence behaviour. Peer networks and pressure also contribute towards an energy-saving attitude. Certain barriers to energy conservation were identified; these include lack of control experienced by the Faculty Managers over equipment installed, as well as a shortage of capital funding. The main obstacles at the residences are lack of upgrading capital, inadequate feedback relating to energy consumption and improper enforcement of policies regarding the usage of certain equipment in dormitory rooms. Certain limitations of the study, for example the number of energy meters, made it difficult to prove beyond doubt to what extent feedback influenced the reduced energy consumption. Information campaigns ran parallel with technological interventions, making it difficult to distinguish the impact of each separately. However, it was established that the use of feedback alone would not achieve energy savings to the desired extent. In conclusion, regular feedback creates awareness, which in turn contributes towards a more energy-conscious culture.

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning

With housing in the UK responsible for over a quarter of all building related carbon dioxide (CO2) emissions, it is becoming increasingly difficult to ignore the impact of occupant behaviour on such emissions. One area where occupant behaviour contributes largely towards emissions is space heating within domestic buildings. Despite technological improvements in the efficiency of heating systems, controls have become increasingly complex. Hence, there is a need to enable people to use their heating controls effectively in order to help reduce the associated CO2 emissions. This research found that significant numbers of people were excluded from using digital programmable thermostats, in particular people over 50 years old. The first study examined the scale of exclusion relating to digital programmable thermostats installed at a specific housing development. A second study explored in detail the reasons for exclusion from successfully programming a range of digital programmable thermostats. This was an in-depth usability study of heating controls that focused on the usability issues experienced by older people and was published in the Journal of Engineering Design. Based upon the outcomes of the first two studies a more inclusive heating control interface prototype was developed. The prototype demonstrated a reduction in both cognitive demands and associated user exclusion. Task success rates increased by 56.3% amongst older participants, and detailed energy modelling indicated that energy savings of 14.5-15.6% annually could be achievable. This work suggests that a more inclusive heating control interface could enable energy savings in the region of 15% through reducing the cognitive demands. Furthermore, this research challenges the existing paradigm and shows that inclusive design research may contribute to sustainable development in an environmental, as well as social, capacity.

The energy use of commercial building operations is a significant contributor to the total global energy demand, and lighting is one of the largest end uses of electricity in commercial buildings. Convention Centers as commercial buildings are examples of big energy consumers, and they present a unique opportunity to showcase benefits of green building techniques due to their large size and broad range of visitors; however, the individual nature of convention centers makes it challenging to find design improvements which will be helpful in general for many convention centers. One exception to this rule of individuality is the presence of public assembly rooms, which are ubiquitous in nature and are used heavily. Traditionally, public assembly rooms are fully enclosed to allow for full control of illumination levels with artificial lighting, particularly fluorescent light. This represents a missing opportunity to utilize daylight or energy efficient artificial light to reduce energy use while enhancing human visual comfort. The objective of this research is to analyze the potential impact of the use of daylight in public assembly rooms. We present the results of a set of computer simulations performed using IES VE software. The simulations are performed as an iterative process, using as base case a north-facing public assembly room in the Tucson Convention Center, and progressively updating the lighting scheme using the software to analyze the illuminance levels for each case. The results are used to propose a lighting scheme for the north-facing public assembly room which uses 100% daylight to achieve a uniform level of illumination and meets the compliance of illumination requirements for public assembly rooms.

Because of global warming the energy production development has progressed towards more renewable energy sources. Biomass has great potential in this matter and pellet is already a big market that has increased seven times the past decade. A periodically strained woodchip resource market and statements of short supply in the future has got actors exploring opportunities with other commodities. Grasses such as Canary grass has shown great potential in this matter and in this study a wetland grass is tested as an additive, 0,5, 1,0, 1,5, and 1,9%, with spruce woodchips. The test production series was performed at a production unit located at the department of environmental and energy system at Karlstad University, Karlstad. Quality was controlled accordingly to the European standard and parameters such as energy consumption, moisture content, mechanical durability and bulk density was tested. For comparison, a sample with only spruce wood chips was produced, and a sample containing 1% of a commonly used additive, potato starch. The results showed that a decrease in energy consumption with 14% when 2% wetland grass was added, part of the decline may be due to the increased production flow compared with the reference sample. The positive effects on decrease in energy consumption, that 1% potato starch results in, is equal to reults from 1% wetlandgrass. This indicates lubricating properties in wetlandgrass. This is attributed to that herbaceous plants have a high content of extracts such as waxes and that they cause less friction in the press. Tests also showed that pellet with wetland grass did not qualify the European standard in terms of mechanical durability. Extracts can form a weak boundary layer in the pellet and cause this. A possible trend shows a better mechanical durability with more grass in pellets. The presence of different size of particles can be a reason. Moisture content qualifies according to the European standard but is below optimum 8%. This despite to relatively high moisture content in the mixer. Higher moisture content in the press would certainly result in a generally higher quality. Suggestions for future studies are to produce pellets with greater distribution on the wetland grass added, to easier interpret a connection. Also examine the extracts behavior with different moisture content. For a sustainable development accordingly renewable energy it is important to ensure the future commodity market for pellets. Further studies should be performed to help the development of alternative raw materials in conjunction with pellet production. / Den globala uppvärmningen är en påverkande faktor gällande dagens energiutveckling. Europeiska unionens krav på mer förnyelsebar energi är därtill en anledning till det ökade intresset för bioenergi. Pelletsmarknaden har sjufaldigt ökat globalt det senaste decenniet med tidvis ansträngd resursmarknad som följd. Träspån anses komma bli en bristvara i framtiden och aktörer ser sig redan om efter alternativa råvaror. Olika typer av gräs som till exempel rörflen har visat sig ha stor potential. I denna studie testas ett våtmarksgräs som additiv i bränslepellets, med 0,5, 1, 1,5, och 1,9% inblandning. Pelletsproduktion samt tester gjordes i pilotanläggningen på Karlstads universitet, avdelningen för miljö-, och energisystem.  Energiförbrukning, fukthalt, hållfasthet och bulkdensitet är några av de variabler som testades. Pellets med våtmarksgräs jämfördes med ett referensprov med endast granspån samt ett prov med ett vanligt förekommande additiv (potatisstärkelse 1%). Kvalitén på pellets bedömdes utifrån den europeiska standarden. Resultatet visade att den specifika elförbrukningen minskade med 14% när 2% våtmarksgräs adderades, en del av den minskningen kan bero på det ökade produktionsflödet jämfört med referensprovet. De positiva effekter på specifik elförbrukning som 1% potatisstärkelse resulterade i, visade våtmarksgräs 1% liknande effekt. Detta indikerar smörjande egenskaper hos våtmarksgräset. En orsak kan vara den höga halt extrakt, såsom vaxer, som många örtartade växter består av. Dessa har i tidigare studier setts minska friktionen i pressen vilket reducerar elförbrukningen. Pellets med våtmarksgräs som additiv klarade inte de Europeiska kraven på hållfasthet. En låg fukthalt och närvaron av extrakt kan ha medfört svaga gränslager i pellets och därmed påverkat hållfastheten negativt. En svag trend visade på förbättring av hållfastheten vid högre andelar våtmarksgräs. Den varierande storleken på partiklar som sampelleteras kan ha bidragit till detta. Fukthalten är godkänd enligt den europeiska standarden men under det optimala 8%. Detta trots en relativt hög uppmätt fukthalt innan pressen. En högre fukthalt i samband med pressning hade troligen höjt kvaliteten generellt. Förslag till vidare studier är att utföra tester med större variation på mängden våtmarksgräs, för att få ett tydligare resultat. Extraktivens beteende i samband med andra varierande parametrar som exempelvis fukthalt, borde studeras närmare för att kunna bedöma våtmarksgräsets möjligheter som additiv. För en hållbar utveckling av förnybar energi är det viktigt att säkerställa den framtida råvarumarknaden för pellets. Fortsatta studier bör göras för att bidra till utvecklingen av alternativa råvaror i samband med pelletsproduktion.

This report presents an implementation of the software part in a software definedradio. The radio is not entirely implemented in software and therefore there arecertain limitations on the received signal. The parts implemented are oscillator,decimation filter, carrier synchronization, time synchronization, package detection,and demodulation. Different algorithms were tested for the different partsto measure the power consumption. To understand how the number of bits usedto represent the signal affects the power consumption, the number of bits wasreduced from 20 bits to 10 bits. This reduction reduced the power consumptionfrom 2.57mW to 1.89mW. A small change in the choice of algorithms was thenmade which reduced the power consumption to 1.86mW. Then the clock rate wasreduced for some parts of the system which reduced the power consumption to1.05mW.

M.Phil. / The main objectives of this study, which was done in Sasol 2, were to analyse energy utilization in the Sasol process and to develop an energy model that simulates all major energy flows in the Sasol process. Secondary objectives were to study the mechanics of the Sasol process and to do a literature study ...

O racionamento de energia elétrica não foi a primeira crise no setor elétrico, sendo que ocorreram anteriormente outras crises no Brasil e em outros países. A causa do déficit, que gerou o racionamento, foi que o crescimento do parque gerador brasileiro não acompanhou o crescimento do consumo da forma adequada. O racionamento produziu impacto no consumo de energia elétrica de forma singular, provocando redução no consumo brasileiro em torno de 24 %, influenciando até onde não houve racionamento e mantendo efeitos no consumo mesmo após o seu término. Foram calculadas as conseqüências do racionamento no consumo de energia elétrica por região, por setor, na demanda e em casos específicos. Os métodos de cálculos foram empregados considerando o crescimento no consumo em 2001, no período pré-crise de energia levando em consideração a sazonalidade dos períodos. As influências do racionamento não ficaram restritas ao consumo de energia elétrica, tendo efeitos no setor elétrico, na indústria, no comércio, na economia, na política nacional e na vida das pessoas em geral. / The electric power rationing was not the first crisis in the electric section, and they happened other crises previously in Brazil and in other countries. The cause of the deficit that generated the rationing, was the growth of the generator Brazilian park didn't accompany the growth of the consumption in the appropriate way. The rationing impactou in the energy consumption electric in a singular way, provoking reduction in the Brazilian consumption around 24%, influencing up to where there was not rationing and maintaining effects in the same consumption after his end. The consequences of the rationing were calculated in the electric energy consumption by area, for section, in the demand and in specific cases. The methods of calculations were employees considering the growth in the consumption in 2001, in the period pré-crisis of energy taking into account the seasonal variation of the periods. The influences of the rationing were not restricted to the electric energy consumption, tends effects in the electric section, in the it elaborates, in the trade, in the economy, in the national politics and in the life of the people in general.

Desempenho e consumo energético são requisitos fundamentais em sistemas de computação. Um desafio comumente encontrado é conciliar esses dois aspectos, buscando manter o mesmo desempenho, consumindo cada vez menos energia. Muitas técnicas possibilitam a redução do consumo de energia em aplicações paralelas, mas na maioria das vezes elas envolvem recursos encontrados apenas em processadores modernos ou um conhecimento amplo das características da aplicação e da plataforma alvo. Nesse trabalho propomos uma abordagem em formato de Workflow. Na primeira fase, o comportamento da aplicação paralela é investigado. A partir dessa investigação, a segunda fase realiza a execução da aplicação paralela com diferentes frequências (mínima e máxima) de processador, utilizando a caracterização das regiões, obtida na primeira fase da abordagem. Esse Workflow foi implementado em formato de biblioteca dinâmica, a fim de que ela possa ser utilizada em qualquer aplicação OpenMP. A biblioteca possui suporte as duas fases do Workflow, na primeira fase é gerado um arquivo que descreve as assinaturas comportamentais das regiões paralelas da aplicação. Esse arquivo é posteriormente utilizado na segunda fase, quando a biblioteca vai alterar dinamicamente a frequência de processador. O benchmark Lulesh é utilizado como cenário de testes da biblioteca, com isso o maior ganho obtido é a redução de 1,89% do consumo de energia. Esse ganho acarretou uma sobrecarga de 0,09% no tempo de execução. Ao comparar nossa técnica com a política de troca de frequência adotada pelo governor Ondemand do Sistema Operacional Linux, o ganho de 1,89% é significativo em relação ao benchmark utilizado, pois nele existem regiões paralelas de curta duração, o que impacta negativamente no overhead da operação de troca de frequência. / Performance and energy consumption are fundamental requirements in computer systems. A very frequent challenge is to combine both aspects, searching to keep the high performance computing while consuming less energy. There are a lot of techniques to reduce energy consumption, but in general, they use modern processors resources or they require specific knowledge about application and platform used. In this work, we propose a performance analysis workflow strategy divided into two steps. In the first step, we analyze the parallel application behavior through the use of hardware counters that reflect CPU and memory usage. The goal is to obtain a per-region computing signature. The result of this first step is a configuration file that describes the duration of each region, their hardware counters, and source code identification. The second step runs the parallel application with different frequencies (low or high) according to the characterization obtained in the previous step. The results show a reduction of 1,89% in energy consumption for the Lulesh benchmark with an increase of 0,09% in runtime when we compare our approach against the governor Ondemand of the Linux Operating System.