The perception of thermal comfort is an important factor influencing the acceptability of residential heating strategies. The perceived thermal comfort may affect a person's inclination to try a strategy or to use it on a long-term basis. In the study, perceived thermal comfort was assessed in relation to room temperature, humidity, clothing worn, preferred room temperatures, personal control over the temperatures, and energy consumption. The relationships among these variables were examined for five families participating in a live-in study comparing five residential heating strategies. The strategies tested included closing off bedroom vents/doors, setting the thermostat at 65°F, and the use of a solar greenhouse and a woodstove as supplemental heat sources. The families lived in a retrofitted solar test house for a period of four to six weeks. The house was equipped with a computer which monitored 37 channels of information at ten-second intervals and recorded the data hourly. The data collected included temperatures in every room, inside and outside humidity, wind velocity, and other variables that interplay in comfort levels and energy use. The ten adult respondents completed daily and weekly questionnaires containing Likert-type scales of thermal comfort and checklists of clothing worn. The results suggest the following conclusions: 1) the use of a residential setting to measure thermal comfort under varying environmental conditions can be successfully accomplished, 2) psychological variables such as personal control should be considered and tested by persons involved in standards development for the thermal environment, 3) the ability and experience of the persons to use a strategy can affect the achieved energy saving benefits of the strategy, 4) personal preference in the amount of personal effort a person is willing or able to give will impact on the decision on whether to use certain strategies, 5) heating strategies that can produce a direct source of heat or at least some warmer areas were rated higher by the project participants, and 6) weather can play an important role in the effectiveness of the solar greenhouse as a heating source. / Ph. D. / incomplete_metadata

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The thesis was initiated by a Consulting Engineering Company (KV3) as a research project to investigate various options in which the efficiency and energy utilisation of conventional air conditioning systems may be enhanced by using alternative and renewable energy. Initially, eight options had been identified and through a process of determining the degree of commercialisation the alternative options were reduced to three. These options, referred to as the sustainable cooling alternatives, are active mass cooling, night flushing and roof cooling system. The roof cooling system comprised a roof-pond, roof-spray, pump and storage tank. The roof cooling system was mathematically and experimentally modelled. The roof cooling experiment was performed under a variety of weather conditions with the roof-pond and storage tank temperatures continuously recorded. The experimentally recorded temperatures were compared to the temperatures generated by the theoretical simulation calculations for the same input and weather conditions. Good agreement was found between the mathematical and experimental model. The largest discrepancy found between the simulated temperature and the experimental temperature was in the order of 1 ºC. A one-room building has been assumed to serve as a basis to which the sustainable cooling alternatives could be applied to for theoretical simulation. The one-room building had four façade walls and a flat roof slab. Night flushing, active mass cooling and the roof cooling system were applied to the one-room building such that the room air temperature and space cooling load could theoretically be simulated. The theoretical simulations were also repeated for the case where the roof-pond and roof-spray were applied as standalone systems to the one-room building. The theoretical simulation calculations were performed for typical summer weather conditions of Stellenbosch, South Africa. Under base case conditions and for a room thermostat setting of 22 ºC the peak cooling load of the one-room building was 74.73 W/m². With the application of night flushing between the hours of 24:00 and 07:00, the room cooling load was reduced by 5.2% by providing 3.9 W/m² of cooling and reducing the peak room temperature by 1.4 ºC. The active mass cooling system was modelled by supplying water at a constant supply temperature of 15 ºC to a pipe network embedded in the roof slab of the one-room building. The sea may typically be considered as a cold water source for buildings situated at the coast. The active mass cooling system reduced the peak cooling load of the one-room building by 50% by providing 37.2 W/m² of cooling and reducing the peak room temperature by 6.7 ºC. When the roof-spray and roof-pond systems were applied as standalone systems to the oneroom building, the peak cooling load of the one-room building could be reduced by 30% and 51% respectively. This is equivalent to 22.3 W/m² of peak cooling by the roof-spray and 38 W/m² of peak cooling by the roof-pond. The roof-spray reduced the peak room temperature by 3.71 ºC while the roof-pond reduced the peak room temperature by 5.9 ºC. Applying the roof cooling system to the one-room building produced 46 W/m² of peak cooling which resulted in a 61.1% reduction in peak cooling load. The roof cooling system reduced the peak temperature by 8 ºC. By comparing the sustainable cooling alternatives, the roof cooling system showed to be the most effective in reducing the one-room building peak cooling load. Over a 24 hour period the roof cooling system reduced the net heat entry to the one-room building by 57.3%. In a further attempt to reduce the peak cooling load, the sustainable cooling alternatives were applied in combinations to the one-room building. The combination of night flushing and roof-spray reduced the peak cooling load by 36% while a combination of night flushing and active mass cooling reduced the peak cooling load by 55%. Combining night flushing with the roof-pond also yielded a 55% peak cooling load reduction. The combination of roofpond, active mass cooling and night flushing provided 51 W/m² of cooling which corresponded to a 68% reduction in peak cooling load. Utilising the sustainable cooling alternatives in a combination in the one-room building gave improved results when compared to the case where the sustainable cooling alternatives were employed as standalone systems. It is illustrated by means of a sensitivity analysis that the ability of the roof cooling system to produce cool water is largely influenced by ambient conditions, droplet diameter and roofspray rate. Under clear sky conditions, an ambient temperature of 15 ºC, relative humidity of 80%, a roof-spray rate of 0.02 kg/sm² and a roof-pond water level of 100mm, water could be cooled at a rate of 113 W/m². The roof-spray energy contributed to 28 W/m² whilst the night sky radiation was responsible for 85 W/m² of the water cooling. It must however be noted that the water of the roof cooling system can never be reduced to a temperature that is lower than the ambient dew point temperature. / AFRIKAANSE OPSOMMING: Die tesis is geïnisieer deur ‘n Raadgewende Ingenieurs Maatskappy (KV3) as a navorsingsprojek om verskeie opsies te ondersoek waarmee die effektiwiteit en energie verbruik van konvensionele lugversorgingstelsels verbeter kan word deur middel van alternatiewe en hernubare energie. Agt opsies is oorspronglik geïdentifiseer en deur middel van ‘n proses waarby die graad van kommersialisering van hierdie alternatiewe maniere bepaal is, kon die opsies verminder word tot drie. Hierdie opsies, ook verwys na as die volhoubare verkoelingsalternatiewe, sluit in aktiewe massa verkoeling, dakverkoeling en nagventilasie. Die dakverkoelingstelsel bestaan uit dakwater, ‘n dakspuit, ‘n pomp en ‘n stoortenk. Die dakverkoelingstelsel is wiskundig en eksperimenteel gemodelleer. Die dakverkoelingseksperiment is uitgevoer onder ‘n verskeidenheid van weersomstandighede. Die dakwater asook die stoortenk se water temperatuur is voortdurend aangeteken. Dieselfde weer- en insetkondisies is gebruik vir die simulasie berekening en die temperature van die stoortenk se water en die dakwater is vergelyk met die temperatuurlesings van die eksperimentele werk. Die temperature van die eksperimentele lesings het goed vergelyk met die temperatuur simulasie berekeninge. Die grootste verskil tussen die simulasie en eksperimentele temperatuur was in die orde grootte van 1 ºC. ‘n Een-kamer gebou is aangeneem om as basis te dien waarop die volhoubare verkoelingsalternatiewe aangewend kon word vir teoretiese simulasie. Die een-kamer gebou het uit vier buite mure en ‘n horisontale beton dak bestaan. Nag ventilasie, aktiewe massa verkoeling en die dakverkoelingstelsel is toegepas op die een-kamer gebou en die kamer se verkoelingslas asook die kamer se lugtempertuur is teoreties gesimuleer. Die teoretiese simulasies is ook herhaal vir die geval waar die dakwater and dakspuitstelsel apart aangewend is op die een-kamer gebou. Die teoretiese simulasie berekeninge is uitgevoer vir tipiese somer weersomstandighede vir Stellenbosch, Suid Afrika. Onder basisgeval omstandighede, waar die een-kamer gebou gesimuleer is, sonder enige volhoubare verkoelingsalternatiewe en ‘n termostaat verstelling van 22 ºC, is die piek verkoelingslas bereken as 74.73 W/m². Met die toepassing van nagventilasie tussen die ure 24:00 en 07:00 was die piekverkoelingslas van die kamer verminder met 5.2% deur 3.9 W/m² se verkoeling te verskaf en die piekkamer temperatuur te verminder met 1.4 ºC. Aktiewe massa verkoeling is gesimuleer deur water teen ‘n konstante temperatuur van 15 ºC te verskaf aan ‘n pypnetwerk, geïnstalleer in the beton dak, van die een-kamer gebou. Geboue geleë aan die kus kan tipies seewater oorweeg as ‘n bron van koue water. Aktiewe massa verkoeling het die piekverkoelingslas van die een-kamer gebou verminder met 50% deur 37.2 W/m² se verkoeling te verskaf en die piekkamer temperatuur te verminder met 6.7 ºC. Wanneer die dakspuit- en dakwaterstelsel aangewend is op die een-kamer gebou as enkel staande stelsels, is die piekverkoelingslas verminder met 30% en 51% onderskeidelik. Dit is ekwivalent aan 22.3 W/m² se verkoeling vir die dakspuitstelsel en 38 W/m² se verkoeling vir die dakwaterstelsel. Die dakspuitstelsel het die piekkamer temperatuur verminder met 3.71 ºC terwyl die dakwaterstelsel ‘n 5.9 ºC verlaging in piekkamer temperatuur tot gevolg gehad het. Die dakverkoelingstelsel het 46 W/m² se piekverkoeling verskaf wat ‘n 61.1% vermindering in piekverkoelingslas tot gevolg gehad het. Die ooreenstemmende piek temperatuur vermindering is 8 ºC. Deur die verskeie volhoubare verkoelingsalternatiewe met mekaar te vergelyk, word getoon dat die dakverkoelingstelsel die mees effektiefste manier is om die een- kamer se piekverkoelingslas te verminder. Oor ‘n tydperk van 24 uur het die dakverkoelingstelsel die totale energievloei na die een-kamer gebou met 57.3% verminder. In ‘n verdere poging om die piekverkoelingslas te verminder, is die volhoubare verkoelingsalternatiewe toegepas in kombinasies op die een-kamer gebou. Die kombinasie van nagventilasie met die dakspuitstelsel het die piekverkoelingslas met 36% verminder, terwyl ‘n kombinasie van nagventilasie en aktiewe massa verkoeling ‘n 55% vermindering in piekverkoelingslas tot gevolg gehad het. Die kombinasie van dakwater en nagventilasie het ook ‘n piekverkoelingslas vermindering van 55% teweeggebring. Die kombinasie van dakwater, aktiewe massa verkoeling en nagventilasie het 51 W/m² se verkoeling veskaf, wat ooreenstem met ‘n 68% vermindering in piekverkoelingslas. Deur die volhoubare verkoelingsalternatiewe in kombinasies toe te pas op die een-kamer gebou, kon beter resultate verkry word toe dit vergelyk is met die geval waar die volhoubare verkoelingsalternatiewe as enkelstaande stelsels toegepas is. Dit is geïllustreer deur middel van ‘n sensitiwiteitsanalise dat die vermoë van die dakverkoelingstelsel om koue water te produseer, beïnvloed word deur buitelug kondisies, waterdruppel deursnee en dakspuit massa vloeitempo. Onder die oop hemelruimteomstandighede, ‘n buitelug temperatuur van 15 ºC, ‘n relatiewe humiditeit van 80%, ‘n dakspuit massa vloeitempo van 0.02 kg/sm² en dakwatervlak van 100 mm, kon water verkoel word teen ‘n tempo van 113 W/m². Die dakspuit gedeelte het 28 W/m² bygedra terwyl die nagruim radiasie sowat 85 W/m² se verkoeling verskaf het. Daar moet egter kennis geneem word dat die water temperatuur van die dakverkoelingstelsel nooit verminder kan word tot onder die buitelug doupunttemperatuur nie.

Energy has always been the dominant driving force for the socio-economic development of mankind. Nowadays, the global energy system is highly depended on fossil fuels. A great share of the final energy consumption, over 40%, in the EU-27 is consumed by the existing building stock whereas dwellings account for 66.62% of this. Thus, the need to increase the energy performance of dwellings is an important instrument in the efforts to lessen Europe’s energy dependency. In order to define measures to increase the energy performance of dwellings a deeper understanding of their characteristics should be gained. Unfortunately, in Cyprus there is a gap in knowledge on this aspect. In this thesis the characteristics of the dwellings in Cyprus are defined through a sample of 500 dwellings. The results revealed that more than 80% of dwellings in Cyprus do not have thermal insulation installed on their envelope. From this it is clear that the definition of the optimum thermal insulation material to be applied in dwellings is very important. Thus, the commercially available thermal insulation materials and topologies used in Cyprus were reviewed and defined through a market survey and the typical dwelling was modelled. The effect of the application of thermal insulation to its energy behaviour was simulated using TRNSYS. This resulted in the definition of the optimum thermal insulation materials and topologies to be applied in both new and existing dwellings. Accordingly, the application of advanced commercially available materials such as Phase Change Materials (PCM) to the envelope of the typical dwelling was investigated. The energy savings achieved by the addition of a PCM layer on the envelope of the typical dwelling was found to be 28.6%. The optimum PCM case was also combined with the optimum thermal insulation combination and an energy saving of 68% was predicted. The incorporation of Renewable Energy Sources (RES) to the typical dwelling was also simulated and studied. Specifically, two types of standalone RES systems were initially evaluated; a solely photovoltaic (PV) system and a hybrid PV-Wind system. The results showed that the solely PV system is a much better option due to the very high solar potential of Cyprus in comparison to the poor wind profile of the island. Subsequently, a grid-connected PV system was also evaluated and the results showed that when a RES system is grid-connected the cost of the system is reduced to half of that of the standalone cases. This research has revealed that the optimum topology combinations to be applied in both new and existing dwellings in Cyprus is thermal insulation plaster or thermal insulation bricks (only for new dwellings) on the external walls combined with expanded polystyrene on the roof. These results will provide valuable information that will assist both engineers and architects in the efficient design of dwellings in Cyprus. The investigation of the application of macroencapsulated PCM showed that these materials are not yet an economically viable solution for application in Cyprus The findings also show that a solely PV system is the optimum RES system to be applied in Cyprus especially when it is grid-connected. The findings of this project are useful for individuals, house builders and designers as well as policy makers for the design of energy saving subsidy schemes.

Thesis (MPhil)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: South Africa faces an energy crisis which presents itself in two forms; electricity generation dominated by coal fired power stations and current electricity supply capacity being unable to meet growth in demand. South Africa urgently requires new generation capacity: however, power stations take time to plan, construct and commission, meaning that South Africa has to consider other options to meet electricity demand. This necessitates quick and innovative ways of meeting future demand. Energy efficiency has been identified as “a low hanging fruit” on the energy tree to address supply constraints and reduce energy related greenhouse gas emissions. There are various energy efficiency programmes aimed at raising awareness of measures that households can take to reduce energy consumption. Some of South Africa’s key objectives of energy efficiency in the residential sector are to mitigate the effect of peak demand on power capacity and to introduce state of the art technologies. In terms of these technologies, there is an overlap between energy efficiency and renewable energy. The widespread installation of renewable energy technologies such as SWHs has the potential to delay the need to construct new power stations. SWHs are a viable renewable energy option for South Africa. It is a mature and proven technology with the potential to address South Africa’s electricity capacity problems. Not only does a SWH provide financial savings to the customer in the long run but it offers the additional benefit of a reduction in greenhouse gas emissions to society. Although awareness of the benefits of solar water heaters is increasing, SWH uptake remains low. However the uptake is increasing due to; a SWH rebate offered through Eskom, electricity price increases which are forcing consumers to seek alternatives and a national building code requiring energy efficient water heating in new buildings which is expected to come into effect in 2012. Liquid Petroleum Gas is a low carbon emitting source of fuel for cooking. In South Africa, middle–high income households rely on the electric stove for cooking. Cooking contributes to electricity peak demand. Reducing electricity demand by replacing the electric stove would help in reducing electricity peak demand from the grid. LPG use has been increasing due to the following reasons; electricity supply shortages, shifting government policy on LPG and increasing electricity tariffs forcing lifestyle changes. This case study sought to investigate the opportunities, as well as the barriers for a Stellenbosch municipality - initiated energy efficiency programme. In terms of energy supply and demand management, the municipality has identified energy efficiency and the introduction of renewable energy sources as options for achieving sustainability. One of the barriers facing energy efficient technologies is up-front costs in the case of SWHs and the cost of appropriate equipment such as gas stoves in the case LPG. The study sought to investigate financial mechanisms that the municipality could use to overcome these barriers and promote the use of SWH and gas stove in the residential sector. Data was collected through a combination of a mini Delphi – expert opinion technique, questionnaires, secondary data analysis, telephone and personal interviews with solar water heater industry stakeholders, LPG industry stakeholders and municipal officials. The conclusion drawn from this research is that Stellenbosch Municipality can initiate its own energy efficiency programme instead of waiting for national government. Although the municipality can initiate an energy efficiency programme, it needs to find another institution to fund the programme. Funding mechanisms however do overcome the barrier of high up -front costs and high gas equipment costs making energy efficient technologies affordable. / AFRIKAANSE OPSOMMING: Suid-Afrika staan voor ʼn energiekrisis wat op twee maniere gestalte kry: elektrisiteitsopwekking wat oorheers word deur steenkoolkragstasies en huidige elektrisiteitsvoorsieningsvermoë wat nie in die groeiende aanvraag kan voorsien nie. Suid-Afrika benodig dringend nuwe kragontwikkelingsvermoë. Dit neem egter tyd om kragstasies te beplan, op te rig en in diens te stel, wat beteken dat Suid-Afrika ander opsies moet oorweeg om in elektrisiteitsaanvraag te voorsien. Dit noodsaak vinnige en innoverende maniere om in toekomstige aanvraag te voorsien. Energierendement is as “ʼn laaghangende vrug” op die energieboom geïdentifiseer ten einde beperkings in kragvoorsiening die hoof te bied en kweekhuisgasuitlatings wat met energie verband hou te verminder. Daar is verskeie energiebesparingsprogramme wat ten doel het om die bewustheid te versterk van maatreëls wat huishoudings kan volg om energieverbruik te verminder. Van Suid-Afrika se vernaamste doelstellings ten opsigte van energierendement in die residensiële sektor is om die uitwerking van spitsaanvraag op kragvermoë te verlig en om die jongste tegnologie in te voer. Ingevolge hierdie tegnologieë is daar ʼn oorvleueling tussen energierendement en hernubare energie. Die algemene installering van hernubare energietegnologieë, soos sonkragwaterverwarming (SWV), het die potensiaal om die noodsaaklikheid van die oprigting van nuwe kragstasies uit te stel. SWV is ʼn lewensvatbare nuwe energieopsie vir Suid-Afrika. Dit is ʼn ontwikkelde en bewese tegnologie met die potensiaal om Suid-Afrika se probleme ten opsigte van elektrisiteitsvermoë die hoof te bied. SWV sorg nie slegs vir die kliënt vir finansiële besparing op die lang duur nie, maar dit bied ook vir die samelewing die bykomende voordeel van ʼn afname in kweekhuisgasuitlatings. Alhoewel die bewustheid van die voordele van sonkragwaterverwarming toeneem, bly die gebruik van SWV laag. Die gebruik is egter besig om toe te neem vanweë ʼn SWV-korting wat deur Eskom aangebied word, elektrisiteitsprysverhogings wat verbruikers dwing om alternatiewe te soek, en ʼn nasionale boureglement wat energiedoeltreffende waterverwarming in nuwe geboue vereis en wat na verwagting in 2012 in werking sal tree. Vloeibare petroleumgas is ʼn brandstofbron wat vir kook gebruik word en wat ʼn lae koolstofvrystelling het. In Suid-Afrika gebruik huishoudings met ʼn middelhoë inkomste die elektriese stoof om te kook. Kook dra by tot elektrisiteitspitsaanvraag. Die vermindering in elektrisiteitsaanvraag deur die vervanging van die elektriese stoof kan help om die elektrisiteitspitsaanvraag op die netwerk te verlaag. Die gebruik van VPG het toegeneem weens die volgende redes: elektrisiteitsvoorsieningstekorte, veranderende regeringsbeleid ten opsigte van VPG en die verhoging in elektrisiteitstariewe wat veranderinge in lewenstyl afdwing. Hierdie gevallestudie het gepoog om die geleenthede, sowel as die hindernisse vir ʼn energierendementprogram wat deur Stellenbosch Munisipaliteit geïnisieer is, te ondersoek. Ten opsigte van energievoorsiening en -aanvraagbestuur het die munisipaliteit energierendement geïdentifiseer en die ingebruikneming van hernubare-energiebronne as opsies om volhoubaarheid te bereik. Een van die hindernisse waarvoor energierenderende tegnologieë te staan kom, is voorkostes in die geval van SWV en die koste van toepaslike toerusting soos gasstowe in die geval VPG. Die studie het ondersoek ingestel na die finansiële meganismes wat die munisipaliteit sou kon gebruik om hierdie hindernisse te bowe te kom en die gebruik van SWV en gasstowe in die residensiële sektor te bevorder. Data is ingevorder deur middel van ʼn kombinasie van ʼn mini-Delphi – kennermeningtegniek, vraelyste, sekondêre data-ontleding, telefoon- en persoonlike onderhoude met belanghebbendes in die sonkragwaterverwarmingsbedryf, belanghebbendes in die VPG-bedryf en munisipale amptenare. Die gevolgtrekking wat uit hierdie navorsing gemaak word, is dat Stellenbosch Munisipaliteit sy eie energierendementprogram kan inisieer in plaas daarvan om vir nasionale regering te wag. Alhoewel die munisipaliteit ʼn energierendementprogram kan inisieer, moet dit ʼn ander instelling kry om die program te befonds. Befondsingsmeganismes oorkom egter die struikelblok van hoë voorkostes en hoë kostes van gastoerusting wat energierenderende tegnologieë bekostigbaar maak.

Thesis (MBA)--Stellenbosch University, 2012. / The consumption of energy results in environmental costs, which include resource shortages, air pollution and radioactive wastes. Due to the economic cost associated, more and more Western industrial organisations are investing in innovative technologies to reduce energy consumption through improved thermal insulation of buildings, modifying equipment and by using energy-saving devices. The organisations are, however, not assured of any savings unless employees handle apparatus and equipment in a manner that conserves energy. Therefore, the important question to answer is how organisational behaviour can be changed to improve and enhance energy conservation efforts. Anglo American Platinum (Amplats) has identified that it needs to change its operations to conserve energy, thus ultimately conserving the planet. The company has identified an internal goal of reducing its energy consumption by fifteen percent, without sacrificing output, over a period of ten years from 2004. Current (2011) energy consumption at the Rustenburg Base Metals Refinery (RBMR) facility indicates that the mentioned goal does not seem achievable in 2014 as anticipated. The proposition to this phenomenon is that the prevailing culture at RBMR is not conducive to a conservation culture as required to conserve energy. Organisational culture is the pattern of values, norms, beliefs, attitudes and assumptions that shape the ways in which people behave and things get done. This hypothesis was tested with a culture survey in the form of an environmental questionnaire. The findings from the questionnaire confirm cultural barriers to achieving centralised targets and goals. Responses to the questionnaire indicated that the organisation does not measure energy conservation efforts accurately and that the information on how to attain the required conservation is not sufficient. The respondents further indicated that they have very limited input into energy conservation efforts and that trust issues present themselves as barriers to achieving set goals and targets. The prevailing perception by the respondents is that inadequate recognition systems are in place to drive the required savings. A surprising finding of the research is that the level of education of the respondents showed no significance with regard to energy conservation and the environment in general. A second interesting finding was that most respondents felt that they could do something to conserve energy and thereby conserve the environment. The challenge facing Amplats is to transform this awareness into a vehicle that will produce significant and sustainable results. Clear and decisive action will be required to bring about cultural change.

Thesis (MBA)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: South Africa is experiencing an energy shortage and volatile supply of electricity. This situation is placing pressure on businesses and citizens and is opening avenues into the renewable sector. This study investigates servicisation as a potential means to assist in the alleviation of energy consumption on the national power grid, and answers whether servicisation in the solar water heating sector could pose as a viable business venture. The main research goal was to investigate whether servicisation within a housing estate could be favourably received. The majority of residents in this high-income bracket were more willing to invest their own capital in renewables rather than being provided with a solar water heater through servicisation. Knowledge of solar water heating is extremely poor amongst consumers, and this contributes to the lack of penetration of solar water heaters in the industry to date. To further exacerbate the situation, installations are often poorly executed, leading to negative experiences by consumers. Initially it was assumed that post 2012, all homes built would be installed with solar geysers or heat pumps, due to legislation. However, surprisingly this was not the case, as a large portion of homes built between 2012 & 2013 have not complied with this legislation.

Thesis (MBA)--Stellenbosch University, 2015. / AFRIKAANSE OPSOMMING: Elektrisiteit is ʼn basiese bron van energie in hedendaagse huishoudings en besighede. Die behoefte na deurlopende elektrisiteit neem toe terwyl die huidige elektrisiteitsverskaffer, ESKOM, ook nie aan die huidige vraag na elektrisiteit kan voorsien nie. Verdere beperkings is die infrastruktuur. Die infrastruktuur is nie so ontwikkel dat elektrisiteit aan 100 persent van die bevolking verskaf kan word nie. Alle plase het nie toegang tot die huidige ESKOM roosterstelsel nie of dit is onprakties om ʼn dienslyn te bou vir die gerief van elektrisiteit. Gevolglik was die meeste boerderybedrywighede in die verlede afhanklik van dieselkragopwekkers. Die gebruik van sonenergie het egter aantrekliker geword en het moontlik meer ekonomies en prakties geword en bied ook ʼn deurlopende krag opsie. Sonstralingsvlakke in Suid Afrika is die hoogste in die wêreld. Die Noord-Kaap word ingesluit in daardie areas in SA wat uiters geskik is vir PV aanlegte. In lande soos Ethiopië en die VSA is sonenergie met PV-tegnologie met groot sukses aangewend in landbouomstandighede vir die voorsiening van elektrisiteit wat ook in SA met sukses aangewend kan word met die uiters geskikte sonbestralingsvlakke. Die grootste voordeel van sonenergie is die oorvloedige beskikbaarheid van die energiebron in SA. Verder is dit volhoubaar, omgewingsvriendelik, hernubaar en heeltemal gratis. Daar is geen bewegende onderdele nie, gevolglik is daar geen geraasbesoedeling nie en is die bedryfskostes van ʼn sonenergie stelsel baie laag. Die nadeel van sonenergie is dat PV-aanlegte slegs elektrisiteit kan opwek wanneer die son skyn. Energiebergingsisteme is nodig om hierdie nadeel te oorbrug of ʼn aanvullende energiebron soos wind moet gebruik word om die tekort aan te vul. Kapitaalspandering is die grootste hindernis in die oprigting van hernubare energiestelsels aangesien dit op een stadium spandeer moet word. Sonenergie is die gewildste energiebron binne die landbousektor in die Noord-Kaap en word deur 88.57 persent van die respondente gebruik terwyl slegs 28.57 persent van die respondente dieselkragopwekkers beskikbaar het as rugsteun fasiliteit vir elektrisiteitvoorsiening. Die belangrikste redes waarom daar oorgeskakel is na sonenergie, was om deurlopende elektrisiteit te verseker en die vermindering van tradisionele energieverbruik. Die studie toon dat sonenergie, oor ʼn 15 jaar leeftyd, ʼn derde van die koste van fossielbrandstowwe kos, alhoewel daar groter aanvanklike kapitaalspandering betrokke is wat as ʼn struikelblok gesien word. Die statistiek wat in die ondersoek versamel is dui daarop dat sonenergie suksesvol aangewend word om te voorsien aan die elektrisiteitbehoeftes van die respondente binne die Noord-Kaap geografiese gebied. Daar is egter geen twyfel dat sonenergie suksesvol, effektief, doeltreffend en ekonomies aangewend kan word as ʼn plaasvervanger vir energie uit fossielbrandstof, binne die landbousektor, op klein en medium skaal in die Noord-Kaap.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Energy-efficient (EE) lighting projects form a substantial percentage of Demand Side Management (DSM) initiatives. These largely entail the exchange of one lighting technology for another more energy-efficient lighting technology. The DSM process typically involves a proposal from an Energy Services Company (ESCO) to retrofit an existing lighting technology with another on the property of a third party, the client. For scoping purposes, ESCOs perform energy savings calculations based on information obtained from the datasheets of the relevant lighting technologies. Such datasheet specifications rarely incorporate the effects of supply voltage fluctuations on energy consumption, which can impact on the accuracy of the savings calculations. Furthermore, modern EE lighting technologies such as Compact Fluorescent lamps (CFLs) employ power electronic circuitry that can in principle give rise to Quality of Supply (QoS) problems such as harmonic distortion. The usage profiles of artificial light fittings targeted in DSM interventions represent another important factor in determining the savings impacts of such projects. There is currently limited information on methodologies for obtaining such usage profiles. In practice, the scoping and impact verification of EE lighting projects are conducted using project-specific applications and spreadsheets that are time-consuming and error-prone. In view of the above-mentioned considerations, this investigation aims to address the lack of voltage-dependent energy consumption data and QoS impacts by conducting a laboratory investigation for all relevant lighting technologies, namely incandescent lamps, CFLs, tubular fluorescent lamps and high intensity discharge lamps. Appropriate mathematical models for the voltage-dependent energy consumption characteristics of these light technologies are derived from the measurements. The supply current harmonic distortion associated with the various lamp types are investigated, particularly with regard to neutral current loading caused by zero-sequence harmonics. Methodologies for obtaining accurate and reliable light usage data using commercially available data loggers are reviewed. A database structure is subsequently designed and implemented to store the information relevant for impact assessment, including the mathematical models of energy consumption, supply voltage profiles and light usage profiles. Finally, an Integrated Software Program (ISP) is developed to implement a methodology for assessing the savings impacts of practical EE lighting projects, using the database as the main input source. The ISP is tested by implementing a real case study. It is shown that the ISP yields accurate results for the case study considered in the evaluation. / AFRIKAANSE OPSOMMING: Energiedoeltreffende (ED) beligtingsprojekte vorm ‟n wesenlike persentasie van vraagkantbestuur (VKB) inisiatiewe. Dit het grootliks te doen met die vervanging van een beligtingstegnologie met ‟n ander meer energiedoeltreffende beligtingstegnologie. Die VKB proses behels normaalweg ‟n voorstel van Energie Dienste Maatskappy (EDM) om ‟n bestaande beligtingstegnologie te vervang met ‟n ander op die perseel van ‟n derde party, die kliënt. EDMs doen energiebesparingsberekeninge op grond van tegniese inligting wat vanaf die datablaaie van die betrokke beligtingstegnologieë verkry word. Hierdie datablad spesifikasies maak selde voorsiening vir die uitwerking van toevoerspanningfluktuasies op energieverbruik, wat die akkuraatheid van die besparingsberekeninge kan beïnvloed. Moderne ED beligtingstegnologieë soos kompakte fluoresseerlampe maak verder gebruik van drywingselektronika stroombane wat in beginsel kan lei tot kwaliteit van toevoer (KVT) probleme soos harmoniese distorsie. Die gebruiksprofiele van kunsmatige lig verteenwoordig nog ‟n belangrike faktor wat die besparingsimpakte van VKB projekte bepaal. Daar is tans beperkte informasie oor die metodologie om sulke gebruiksprofiele te verkry. In die praktyk word die verifiëring van die impak van ED beligtingsprojekte gedoen deur gebruik te maak van projekspesifieke programme en sigblaaie wat tydrowend is en geneig is om te lei tot foute. In die lig van die bogenoemde oorwegings, streef hierdie ondersoek om die tekort aan spanningsafhanklike energieverbruiksdata en KVT impakte te aan te spreek deur „n laboratorium ondersoek uit te voer vir al die relevante beligtingstegnologieë, naamlik filament lampe, kompakte fluoresseerlampe, buisvormige fluoresseerlampe en hoë-intensiteit ontladingslampe. Gepaste wiskundige modelle vir die spanningsafhanklikeenergieverbruik eienskappe van hierdie beligtingstegnologieë word vanuit die metings afgelei. Die harmoniese vervorming van die toevoerstroom van die verskillende beligtingstegnologieë word ondersoek, veral met verwysing tot neutraalstroombelasting wat veroorsaak word deur zero volgorde harmoniese ordes. Metodologieë vir die verkryging van akkurate en betroubare ligverbruikprofiele deur die gebruik van komersieel beskikbare dataversamelaars is nagegaan. ͗n Databasis struktuur is vervolgens ontwerp en geïmplementeer om die toepaslike inligting vir bepaling van die impakte te stoor, insluitend die wiskundige modelle vir energieverbruik, toevoerspanning-en ligverbruikprofiele. ‟n Geïntegreerdesagtewareprogram (GSP) is ontwerp om die metodologie vir die bepaling van besparingsimpakte van praktiese ED beligtingsprojekte te implimenteer, deur gebruik te maak die databasis as die hoofbron van insette. Die GSP is getoets deur ‟n werklike gevallestudie te implimenteer. Daar is bewys dat die GSP akkurate resultate lewer vir die gevallestudie wat in die evaluering gebruik is.

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

Security is a primary concern in this era of pervasive computing. Hardware based security mechanisms facilitate the construction of trustworthy secure systems; however, existing hardware security approaches require modifications to the micro-architecture of the processor and such changes are extremely time consuming and expensive to test and implement. Additionally, they incorporate cryptographic security mechanisms that are computationally intensive and account for excessive energy consumption, which significantly degrades the performance of the system. In this dissertation, I explore the domain of hardware based security approaches with an objective to overcome the issues that impede their usability. I have proposed viable solutions to successfully test and implement hardware security mechanisms in real world computing systems. Moreover, with an emphasis on cryptographic memory integrity verification technique and embedded systems as the target application, I have presented energy efficient architectures that considerably reduce the energy consumption of the security mechanisms, thereby improving the performance of the system. The detailed simulation results show that the average energy savings are in the range of 36% to 99% during the memory integrity verification phase, whereas the total power savings of the entire embedded processor are approximately 57%.