Thesis (MBA (Business Management))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: It has been established worldwide that energy efficiency undertakings are the fastest, most cost-effective and cleanest way to extend energy supplies. When the energy supply made available through energy efficiency projects are compared with increasing primary supply through building new conventional generation facilities, the former is in most cases also safer, more reliable and a more secure form of investment. Energy service companies (ESCOs) are the recognised implementation vehicles of energy efficiency projects and have been in use internationally for many years for this purpose. Globally, however, ESCOs do not have a good history of being viable business enterprises. The most important barriers identified internationally hindering ESCOs’ growth and sustainability were the potential customers’ lack of awareness, information and understanding regarding energy efficiency projects, the financing of these projects, as well as the support of government on energy efficiency policies and regulations. The urgency of implementing energy efficiency measures in South Africa is critical based on the precarious situation of the national electrical suppliers’ ability to provide electricity unfailingly to all its current and future customers. The South African electrical energy situation should therefore provide tremendous opportunities to the local ESCO industry. The aim of this study was therefore to reiterate the importance of energy efficiency projects and to describe the barriers to growth and sustainability experienced by ESCOs in South Africa against the international backdrop. This was done by way of a survey sent out to all registered ESCOs in South Africa. Based on the responses to the survey, the South African industry is in dire straits and is hindered by various barriers to their growth and sustainability. The study identified eight major barriers in the South African ESCO industry which are similar to those experienced by ESCOs internationally. The uniqueness of the local barriers however, is that the industry operates in a highly regulated environment and that these regulators, being the government and Eskom, are recognised as the main perpetrators responsible for most of these barriers, largely due to a lack of dedicated action. Furthermore, the study shows that it is critical for all role players in the South African energy efficiency industry, and specifically the South African government and Eskom, to recognise these barriers and to assist in solving them to improve the growth opportunities in the ESCO industry. Removal of these barriers will not only improve the electricity situation, but will also have a number of positive effects on the micro and macro-economic levels of South Africa, as well as the environment. Finally, the study makes suggestions about the way forward through a number of actions to be taken to lower or remove the most important of these barriers. / AFRIKAANSE OPSOMMING: Dit is reeds wêreldwyd bevestig dat energie-effektiwiteitsprojekte die vinnigste, kostedoeltreffendste en omgewingsvriendelikste manier is om energiebronne uit te brei. Wanneer die energieverskaffing wat beskikbaar gestel word deur energieeffektiwiteitsprojekte vergelyk word met die vermeerdering van primêre energie deur die bou van nuwe konvensionele opwekkingsfasiliteite, is eersgenoemde in die meeste gevalle ook veiliger en ’n meer betroubare en stabiele beleggingsvorm. Energie-diensmaatskappye (energy service companies (ESCOs)) is die erkende implementeringsmediums vir energie-effektiwiteitsprojekte en word reeds baie jare lank internasionaal vir hierdie doel aangewend. ESCOs het egter wêreldwyd nie ’n goeie rekord as lewensvatbare sake-ondernemings nie. Die vernaamste hindernisse wat ESCOs se groei en welvaart stuit is internasionaal geïdentifiseer as voornemende kliënte se gebrek aan bewustheid, inligting en begrip rakende energie-effektiwiteitsprojekte, die finansiering van sodanige projekte, asook die ondersteuning van die regering ten opsigte van energieeffektiewiteitsbeleide en -regulasies. Daar is groot dringendheid om energie-effektiewe projekte en maatreëls in Suid Afrika te implementeer, gebaseer op die huidige onsekerheid of die nasionale elektrisiteitsverskaffer wel in staat is om ’n betroubare bron van elektrisiteit aan sy huidige en voornemende kliënte te voorsien. Die Suid Afrikaanse elektriese energie situasie behoort daarom heelwat geleenthede te skep vir die plaaslike ESCO-industrie. Die doel van hierdie studie was dus om die belangrikheid van energie-effektiwiteitsprojekte te beklemtoon en om die hindernisse te omskryf wat ESCOs in Suid Afrika se groei en welvaart stuit, gesien vanuit ‘n internasionale perspektief. Dit was gedoen deur ‘n vraelys aan alle geregistreerde ESCOs te stuur. Na aanleiding van die terugvoering op die vraelyste, sukkel hierdie industrie om kop bo water te hou weens verskeie hindernisse wat hulle groei en welvaart stuit. Hierdie studie identifiseer agt belangrike hindernisse in die Suid-Afrikaanse ESCO industrie wat ooreenstem met die wat deur internasionale ESCOs ondervind word. Die uniekheid van die plaaslike hindernisse is egter dat die industrie werksaam is in ‘n streng gereguleerde omgewing en dat die reguleerders, die regering en Eskom, ook uitgewys word as die vernaamste skuldiges wat verantwoordelik is vir meeste van die hindernisse, hoofsaaklik as gevolg van hulle gebrek aan toegewyde uitvoering van take. Die bevindinge van hierdie studie toon verder dat dit krities is vir al die rolspelers in die Suid-Afrikaanse energie-effektiwiteitsindustrie, spesifiek die Suid-Afrikaanse regering en Eskom, om hierdie hindernisse te erken en om saam te werk om hulle te oorkom en sodoende die groeigeleenthede in die ESCO-bedryf te verbeter. Die verwydering van hierdie hindernisse sal nie alleen die elektrisiteitsituasie verbeter nie, maar sal ook ’n aantal positiewe invloede hê op die mikro- en makro-ekonomiese vlak van Suid-Afrika, sowel as die omgewing. Die studie sluit af met voorstelle rakende die uitvoering van verskeie aksies wat die verwydering van die vernaamste hindernisse tot gevolg sal hê, of die hindernisse se impak op die industrie sal verminder.

The global energy usage have been growing and is expected to grow in the forthcoming years. The negative effects of increased energy use are greatly depending on the type of base raw materials required for converting the energy and the negative consequences those have on the environment. From the energy used, fossil fuels stands for the largest part. Excess use of fossil fuels have been shown to have considerable negative effects on the environment, including, but not limited to global warming. Renewable energy is today the world’s fastest growing energy source limiting the negative consequences of growing energy use. The commercial and residential buildings stands together for about 40 % of the total energy usage. Residential buildings alone stands for 20 % of the total world delivered energy consumption by end-use sector. In EU the average residential energy use amounts to 25 % and for individual countries like Sweden and Finland it is 21 %. The EU energy efficiency directive from year 2012 sets a target to save 20 % of the unions primary energy usage by year 2020 compared to the year 1990. The EU countries also agreed in October 2014 on a new energy efficiency target of at least 27 % by the year 2030. To reach this goal, improved energy efficiency are required in all sectors. Finland’s energy efficiency law for buildings from 2013 greatly reduces the minimum energy usage allowed for new buildings. Finland is also preparing for a new law that would by 2020 require all new buildings to be zero or close to zero energy buildings. This is defined by the Ministry of the Environment as buildings that have very high energy efficiency, where the already greatly reduced energy demand is satisfied extensively by renewable energy. As part of the goal to greatly increase buildings energy efficiency, this work focus on heat exchangers for showers. The purpose of this project is to investigate how two different heat exchangers works for shower cabins. This is done by testing a system where the heat exchangers are linked together. The system works by transferring heat from the drainage water and the moist air to the incoming colder drinking water before the cold water is heated in the mixerto desired shower temperature. The measurements are taken for different simulated shower situations. The Heat exchangers efficiency are calculated and the energy savings are examined with annual energy savings. The payback time shows that the system is not currently viable. The efficiency need to be improved, the main issue being the constituent materials heat transfer attributes between cold and hot water. The results are discussed and it is concluded that the system would be viable with improved heat exchanger efficiency and adequate shower use, which depends on the user and the amount of people using the shower. The main issue with increased heat transfer efficiency is the greater risk of contamination between the incoming cold drinking water and the outgoing dirty drainage water.

Sensor nodes are deployed over sensing fields for the purpose of monitoring certain phenomena of interest. The sensor nodes perform specific measurements, process the sensed data, and send the data to a base station over a wireless channel. The base station collects data from the sensor nodes, analyses this data, and reports it to the users. Wireless sensor networks are different from traditional networks, because of the following constraints. Typically, a large number of sensor nodes need to be randomly deployed and, in most cases, they are deployed in unreachable environments; however, the sensor nodes may fail, and they are subject to power constraints. Energy is one of the most important design constraints of wireless sensor networks. Energy consumption, in a sensor node, occurs due to many factors, such as: sensing the environment, transmitting and receiving data, processing data, and communication overheads. Since the sensor nodes behave as router nodes for data propagation, of the other sensor nodes to the base station, network connectivity decreases gradually. This may result in disconnected sub networks of sensor nodes. In order to prolong the network's lifetime, energy efficient protocols should be designed for the characteristics of the wireless sensor network. Sensor nodes in different regions of the sensing field can collaborate to aggregate the data that they gathered. Data aggregation is defined as the process of aggregating the data from sensor nodes to reduce redundant transmissions. It reduces a large amount of the data traffic on the network, it requires less energy, and it avoids information overheads by not sending all of the unprocessed data throughout the sensor network. Grouping sensor nodes into clusters is useful because it reduces the energy consumption. The clustering technique can be used to perform data aggregation. The clustering procedure involves the selection of cluster heads in each of the cluster, in order to coordinate the member nodes. The cluster head is responsible for: gathering the sensed data from its cluster's nodes, aggregating the data, and then sending the aggregated data to the base station. An adaptive clustering protocol was introduced to select the heads in the wireless sensor network. The proposed clustering protocol will dynamically change the cluster heads to obtain the best possible performance, based on the remaining energy level of sensor nodes and the average energy of clusters. The OMNET simulator will be used to present the design and implementation of the adaptive clustering protocol and then to evaluate it. This research has conducted extensive simulation experiments, in order to fully study and analyse the proposed energy efficient clustering protocol. It is necessary for all of the sensor nodes to remain alive for as long as possible, since network quality decreases as soon as a set of sensor nodes die. The goal of the energy efficient clustering protocol is to increase the lifetime and stability period of the sensor network. This research also introduces a new bidirectional data gathering protocol. This protocol aims to form a bidirectional ring structure among the sensor nodes, within the cluster, in order to reduce the overall energy consumption and enhance the network's lifetime. A bidirectional data gathering protocol uses a source node to transmit data to the base station, via one or more multiple intermediate cluster heads. It sends data through energy efficient paths to ensure the total energy, needed to route the data, is kept to a minimum. Performance results reveal that the proposed protocol is better in terms of: its network lifetime, energy dissipation, and communication overheads.

As part of the UK’s effort to combat climate change, deep reductions in carbon emissions will be required from existing social housing. This thesis explores the viability of achieving such a goal through a case-study approach, focusing on Peabody, a large housing association operating in London. A model was developed for Peabody’s existing housing stock that quantifies the impacts of technical carbon reduction interventions on stock carbon emissions, Peabody’s expenditure and residents’ fuel bills for the period up to 2030. A participant observation study, conducted from 2006 to 2009, explored the impact of contextual factors influencing the viability of Peabody carrying out the considered technical interventions. The model study found that the Greater London Authority’s target of achieving 60% emission cuts by 2025 could be achieved, but only through extensive stock refurbishment, including a widespread use of solid wall insulation. An external context of substantial reductions in the carbon intensity of the national grid and constrained resident demand for energy is also required. Even where considerable financial support for refurbishment from Government was assumed, the model provided evidence of a funding gap of tens of millions of pounds which would need to be bridged if the required measures were to be carried out. The participant observation study found that the prohibitive cost of carrying out carbon reduction measures is the key barrier currently holding back progress. Other significant issues are related to Government policy, including the inability to raise income from residents to offset refurbishment spending, and the lack of a long term framework to drive action to reduce emissions from existing UK housing. By coupling an analysis of technical interventions with analysis of their financial and political viability, this thesis demonstrates that the achievement of deep emission cuts from Peabody’s existing stock is certainly possible, but requires changes in Government policy and increased efforts from all stakeholders concerned if it is to come to pass.

<p>One of the great challenges facing society is to convert theglobal energy system to a sustainable process. Currently, 80%of the world´s energy is supplied through the combustionof fossil fuels. Not only are the fossil resources limited, theutilisation also increases the level of greenhouse gases in theatmosphere. The convertion to a sustainable energy system isproblematic since the technology needed to exploit mostnon-fossil energy sources is not yet fully developed, e.g.solar energy. Biofuel is an available renewable energy sourcewhich is already widely used in many countries. If an effectiveswitch-over from fossil fuels to biofuels is to be realised,biofuels must be viewed as a limited resource. Consequently, itis important that the handling, upgrading and utilisationprocesses involving biofuels are efficient so that itspotential can be fully exploited.</p><p>This thesis considers efficient biofuel utilisation andupgrading within the sawmill industry. The goal has been toanalyse not only the technical opportunities for energy savingsin the sawmill industry, but also to analyse the costeffectiveness and environmental impact of studied measures. Theheat demand of the sawmill industry is almost completelycovered by its own by-products; primarily bark, sawdust andwood chips. The increased demand and improved economic value ofwoody biofuels on the market is thus an incentive for thesawmill industry to place more focus on energy issues. Thesawmill industry also has a more or less constant heat loadover the year, which is a beneficial factor for integrationwith district heating networks, biofuel upgrading plants andcombined heat and power plants.</p><p>The conclusion of the study is that a variety of energyproducts such as heat, unrefined biofuel, pellets andelectricity can be efficiently produced in the sawmill industryand sold for profit to external customers. The payback periodsfor the proposed investments are moderate and both theemissions of volatile organic compounds and global CO2 aredecreased. Should the proposed measures be fully implemented atSwedish sawmills, about 2.8 TWh of biofuel could be savedannually, 0.5 TWh of waste heat could be sold as districtheating and 0.8 TWh of green electricity could be produced.Language: English</p><p><b>Keywords:</b>Sawmill industry, energy efficiency, heatrecovery, integration, biofuel, upgrading, district heating,fuel pellets, CHP, VOC, CO2</p>

Low power and Lossy Networks (LLNs) such as wireless sensor networks are currently used in many important applications fields such as remote environment monitoring and target tracking. This deployment has been enabled by the availability, especially in recent years, of embedded micro-controller devices that are smaller and cheaper. These devices are equipped with wireless interfaces, with which they can communicate with each other to form a network. In this thesis we focus on studying the energy consumption of reliable transport protocols over LLNs. Recently, much research has been carried out to improve the reliability and the congestion control on low power networks. Some of these works have considered TCP inappropriate for this kind of networks. Indeed, the idea of deploying TCP was rejected due to its header overhead, its end-to-end retransmission mechanism, its large rate of acknowledgment, and the impact of the lower layers fragmentation on the energy consumption. Nonetheless, the use of standard TCP/IP protocols offers the advantage of a seamless connectivity between the wireless network and the Internet. TCP allows easily the use of standard applications (HTTP, SSH) for some tasks like reprogramming of nodes or firmware updates, without the need of deploying complex proxies in border routers. In the first part of this work, we study the energy consumption of TCP and the ways that reduce its energy consumption. We study one of the proposed TCP algorithms to reduce the end-to-end retransmissions cost and we propose some improvements that allow it to reduce the energy consumption. Then, we study the compression of the TCP header over low-power and lossy networks and we consider IPv6 over Low power Wireless Personnel Area Networks (6LoWPAN) as an example. We propose a new TCP header compression algorithm that reduces the TCP header size to about six bytes. In the second part, we propose a mathematical model that allows to estimate the energy consumption of wireless nodes. Using the model, we study the tradeoff between sending long and short TCP segments and their impact on the energy consumption. Finally, we study the impact of a new fragment recovery mechanism on the energy performance of TCP.

Growing demand for electricity forces suppliers to expand their generation capacity. Financing these expansion programmes results in electricity cost increases above inflation rates. By reducing electricity consumption, additional supply capacity is created at lower costs than the building of conventional power stations. Therefore, there is strong justification to reduce electricity consumption on the supplier and consumer side. The mining and industrial sectors of South Africa consumed approximately 43% of the total electricity supplied by Eskom during 2012. Approximately 10% of this electricity was used to produce compressed air. By reducing the electricity consumption of compressed air systems, operating costs are reduced. In turn this reduces the strain on the South African electricity network. Previous energy saving projects on mine compressed air systems realised savings that were not always sustainable. Savings deteriorated due to, amongst others, rapid employee turnover, improper training, lack of maintenance and system changes. There is therefore a need to improve projects that have already been implemented on mine compressed air systems. The continuous improvement of equipment (such as improved control valves) and the availability of newer technologies can be used to improve existing energy saving strategies. This study provides a solution to reduce the electricity consumption and operating costs of a deep level mine compressed air system. This was achieved by modernising and improving an existing underground compressed air saving strategy. This improvement resulted in a power saving of 1.15 MW; a saving equivalent to an annual cost saving of R4.16 million. It was found that the improved underground compressed air DSM project realised significant additional electrical energy savings. This resulted in ample cost savings to justify the implementation of the project improvements. It is recommended that opportunities to improve existing electrical energy saving projects on surface compressed air systems are investigated. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

The energy performance in buildings is influenced by many factors, such as ambient weather conditions, building structure and characteristics, occupancy and their behaviors, the operation of sub-level components like Heating, Ventilation and Air-Conditioning (HVAC) system. This complex property makes the prediction, analysis, or fault detection/diagnosis of building energy consumption very difficult to accurately and quickly perform. This thesis mainly focuses on up-to-date artificial intelligence models with the applications to solve these problems. First, we review recently developed models for solving these problems, including detailed and simplified engineering methods, statistical methods and artificial intelligence methods. Then we simulate energy consumption profiles for single and multiple buildings, and based on these datasets, support vector machine models are trained and tested to do the prediction. The results from extensive experiments demonstrate high prediction accuracy and robustness of these models. Second, Recursive Deterministic Perceptron (RDP) neural network model is used to detect and diagnose faulty building energy consumption. The abnormal consumption is simulated by manually introducing performance degradation to electric devices. In the experiment, RDP model shows very high detection ability. A new approach is proposed to diagnose faults. It is based on the evaluation of RDP models, each of which is able to detect an equipment fault.Third, we investigate how the selection of subsets of features influences the model performance. The optimal features are selected based on the feasibility of obtaining them and on the scores they provide under the evaluation of two filter methods. Experimental results confirm the validity of the selected subset and show that the proposed feature selection method can guarantee the model accuracy and reduces the computational time.One challenge of predicting building energy consumption is to accelerate model training when the dataset is very large. This thesis proposes an efficient parallel implementation of support vector machines based on decomposition method for solving such problems. The parallelization is performed on the most time-consuming work of training, i.e., to update the gradient vector f. The inner problems are dealt by sequential minimal optimization solver. The underlying parallelism is conducted by the shared memory version of Map-Reduce paradigm, making the system particularly suitable to be applied to multi-core and multiprocessor systems. Experimental results show that our implementation offers a high speed increase compared to Libsvm, and it is superior to the state-of-the-art MPI implementation Pisvm in both speed and storage requirement.

With the current trend of CO2 mitigation in process industries, the primary goal of this thesis is to promote biomass as an energy and reduction agent source to substitute fossil sources in the steel industry. The criteria for this substitution are that the steel process retains the same function and the integrated energy efficiency is as high as possible. This work focuses on advanced gasification of biomass and waste for substitution of fossil fuels in steel industry heat treatment furnaces. To achieve this, two approaches are included in this work. The first investigates the gasification performance of pretreated biomass and waste experimentally using thermogravimetric analysis (TGA) and a pilot plant gasifier. The second assesses the integration of the advanced gasification system with a steel heat treatment furnace. First, the pyrolysis and char gasification characteristics of several pretreated biomass and waste types (unpretreated biomass, steam-exploded biomass, and hydrothermal carbonized biomass) were analyzed with TGA. The important aspects of pyrolysis and char gasification of pretreated biomass were identified. Then, with the objective of studying the gasification performance of pretreated biomass, unpretreated biomass pellets (gray pellets), steam-exploded biomass pellets (black pellets), and two types of hydrothermal carbonized biomass pellets (spent grain biocoal and horse manure biocoal) were gasified in a fixed bed updraft gasifier with high-temperature air/steam as the gasifying agent. The gasification performance was analyzed in terms of syngas composition, lower heating value (LHV), gas yield, cold gas efficiency (CGE), tar content and composition, and particle content and size distribution. Moreover, the effects on the reactions occurring in the gasifier were identified with the aid of temperature profiles and gas ratios. Further, the interaction between fuel residence time in the bed (bed height), conversion, conversion rate/specific gasification rate, and superficial velocity (hearth load) was revealed. Due to the effect of bed height on the gasification performance, the bed pressure drop is an important parameter related to the operation of a fixed bed gasifier. Considering the limited studies on this relationship, an available pressure drop prediction correlation for turbulent flow in a bed with cylindrical pellets was extended to a gasifier bed with shrinking cylindrical pellets under any flow condition. Moreover, simplified graphical representations based on the developed correlation, which could be used as an effective guide for selecting a suitable pellet size and designing a grate, were introduced. Then, with the identified positive effects of pretreated biomass on the gasification performance, the possibility of fuel switching in a steel industry heat treatment furnace was evaluated by effective integration with a multi-stage gasification system. The performance was evaluated in terms of gasifier system efficiency, furnace efficiency, and overall system efficiency with various heat integration options. The heat integration performance was identified based on pinch analysis. Finally, the efficiency of the co-production of bio-coke and bio-H2 was analyzed to increase the added value of the whole process. It was found that 1) the steam gasification of pretreated biomass is more beneficial in terms of the energy value of the syngas, 2) diluting the gasifying agent and/or lowering the agent temperature compensates for the ash slagging problem in biocoal gasification, 3) the furnace efficiency can be improved by switching the fuel from natural gas (NG) to syngas, 4) the gasifier system efficiency can be improved by recovering the furnace flue gas heat for the pretreatment, and 5) the co-production of bio-coke and bio-H2 significantly improves the system efficiency. / <p>QC 20160825</p>

<p>Na regionalnom planu evidentne su potrebe za visokim energetskim performansama, promenom strukture izvora energije i modernizacijom energetske infrastrukture, što zahteva novi i inoviran razvojni put praćen korenitim promenama i sistemskim pristupom a u skladu sa novim društvenim, ekonomskim i tehnološkim prilikama. Takav razvojni put bi učinio regionalne energetske sisteme efikasnim i održivim i predstavlja energetsku tranziciju. Disertacija kombinuje različite tehnike i pristupe za analizu mnogih aspekata razvoja regionalnih energetskih sistema od kojih su najvažniji povećanje energetske efikasnosti u sistemima proizvodnje energije, diversifikaciju izvora energije (kombinovanje obnovljivih i neobnovljivih izvora energije) i poboljšanja u energetskoj infrastrukturi (nova i savremena tehnološka rešenja).</p> / <p>At the regional level, there are evident needs for a high energy performance, change the structure of energy sources and modernization of the energy infrastructure, which requires a new and innovative development path, followed by fundamental changes and systemic approach in accordance with the new social, economic and technological conditions. Such a development path would make regional energy systems efficient and sustainable and represents the energy transition.<br />The thesis combines a variety of techniques and approaches for the analysis of many aspects of the development of regional energy systems, but especially increasing of energy efficiency in energy production systems, diversification of energy sources (a combination of renewable and non-renewable energy sources) and improvements in energy infrastructure (new and modern technological solutions).</p>