Within the international context, energy has become a central factor in our everyday ways of life. There is increasing dependence on energy resources such as electricity to improve people quality of life. In developing countries, many people still do not have access to energy due to several challenges that have hindered infrastructural development and economic growth. At the same time, there is a growing interest in the protection of the environment and addressing issues of climate change. Green technologies such as solar water heaters are identified as technologies that meet the need of both its end-users and the environment through the provision of hot water. Access to 'hot water' is seen to be an important element resulting in an improved quality of life. In addition, several methods of heating water are explored to assess the attitudes and perceptions that people have towards solar water heaters. The dissertation involved in-depth interviews with residents from low income RDP houses in Kwandengezi Coffee Farm and government officials from eThekwini Municipality involved in the solar water heater programme for low income communities. The interviews revealed that renewable energy interventions such as the solar heater programme for low income communities contribute significantly to an improvement in people‘s quality of life. The availability of solar heaters allows people to enjoy hot water at a free cost, hence an improvement in the quality of life. The research further revealed that such renewable energy interventions can contribute to a reduction in negative environmental impacts, hence facilitating the acquisition of hot water with less dependence on electricity resources. / M.Dev.Studies University of KwaZulu-Natal, Durban 2013.

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Η παρούσα διπλωματική εργασία έχει ως θέμα τον ευφυή έλεγχο μιας μηχανής Stirling χαμηλής θερμοκρασιακής διαφοράς, με στόχο την πρακτική εφαρμογή σε οικιακούς καταναλωτές για την παραγωγή ηλεκτρικής ενέργειας. Έγινε διασύνδεση μιας σειρά αισθητήρων (μέτρηση θερμοκρασίας) και επενεργητών (αντλίες) σε ένα πρωτότυπο σύστημα, έτσι ώστε να προσομοιωθεί κατά το καλύτερο δυνατό τρόπο η λειτουργία της αύξησης της θερμοκρασίας του υγρού σε ένα ηλιακό θερμοσίφωνα και της τυπικής οικιακής ημερήσιας κατανάλωσης. Με βάση αυτό το πρότυπο παραγωγής και κατανάλωσης ενέργειας διαμορφώθηκε ένας ευριστικός έλεγχος έτσι ώστε να παραχθεί η περισσότερη ηλεκτρική ενέργεια χωρίς να παραβιασθούν μία σειρά από περιορισμούς που αφορούν στην χρήση του ηλιακού θερμοσίφωνα. Πειραματικά αποτελέσματα επιβεβαιώνουν την αποτελεσματικότητα της μηχανής Stirling και την ανάγκη προσαρμοστικοτητας της λειτουργίας της έτσι ώστε να ανταποκρίνεται στις ιδιάζουσες ανάγκες της κάθε οικογένειας. / This thesis is on the intelligent control of a Stirling engine with a low temperature difference in order to practice residential consumers for electricity production. An interface of a series of sensors (temperature measurement) and actuators (pumps) became in a prototype system in order to simulate as best as possible the function of warming the liquid in a solar water heater and the standard daily household consumption. Under this model of production and consumption was a Heuristic control order to generate more electricity without having violated a number of restrictions on the use of solar water heater. Experimental results confirm the effectiveness of the Stirling engine and the need for adaptability of its operation to meet the specific needs of each family.

Orientador: João Francisco Escobedo / Banca: Dinival Martins / Banca: Alexandre Dal Pai / Banca: Erico Tadao Teramoto / Banca: Ricardo Molto Pereira / Resumo: O principal objetivo deste estudo é avaliar, com bases em resultados experimentais, um sistema de aquecimento solar constituído de mangueira de polietileno que permite a transferência do calor gerado pela radiação solar direta e/ou difusa (Energia Solar Térmica) para a água. O sistema foi dimensionado para atender a demanda de um Centro de Ressocialização com capacidade para 220 internos. Justifica-se a escolha do tema pelo fato de que consiste em um assunto atual de grande relevância, principalmente porque vive-se uma crise energética em nível mundial. O estudo comprova através de um experimento a viabilidade do aquecedor solar de baixo custo, considerando-se sua aplicabilidade em locais que demanda grande volume de água aquecida para banho. Os resultados demonstraram que o sistema alternativo proposto atendeu de forma eficiente e econômica a demanda solicitada, o que pode ser adotada pelo poder público em qualquer um de seus segmentos que necessite de água aquecida, com objetivo de reduzir custos e contribuir com o sistema energético brasileiro. O sistema foi analisado para atuar em fluxo continuo e fluxo intermitente, ambos objetivando aquecer a água a temperaturas superiores a 37 °C no inverno. Os resultados alcançados atenderam as expectativas coletando grandes volumes, com temperaturas médias acima de 42 °C. / Abstract: The aim of this study is to evaluate, with bases on experimental results, a solar heating system consists of polyethylene hose that allows the transfer of heat generated by direct solar radiation and / or diffuse (Solar Thermal Energy) to the water. The system has been designed to meet the demand of a Rehabilitation Center with a capacity for 220 inmates. Justified the choice of the theme for the fact that consists of a current subject of great importance, especially because it lives in an energy crisis worldwide. The study proves through an experiment the viability of solar heater low cost, considering their applicability in places that demand large volume of heated water for bathing. The results showed that the alternative system proposed met efficiently and economically the requested demand, which can be adopted by the government in any of its segments that need heated water, in order to reduce costs and contribute to the Brazilian energy system. The system was analyzed to operate in continuous flow, intermittent flow, both aiming at heating the water to temperatures above 37 °C in winter. The results achieved met the expectations collecting large volumes, with average temperatures above 42 °C. / Doutor

The nighttime losses from an integral collector storage (ICS) system were investigated. The significance of the sky temperature, wind speed, and ambient temperature on the losses were examined. Outdoor data was taken on several nights to characterize the thermal performance of an ICS system under various environmental conditions. Indoor tests were then performed under an artificial "nighttime sky" environment, with a simulated wind, in an attempt to duplicate the heat losses which occurred outdoors. The standard rating procedure which specifies the conditions for the heat loss tests for ICS systems was analyzed to see how well it characterizes the collector performance at night. Experimental results indicate a synergistic effect between the sky temperature and wind speed. The effects of wind on the losses from the ICS system overshadow the effects of small changes in sky temperature, but larger changes of sky temperature, with a constant wind speed, have a pronounced effect. It is recommended that both of these parameters be taken into account in heat loss tests in standard rating procedures. Indoor tests can duplicate outdoor heat loss results within 8 per cent. The minimum requirement for SRCC rating tests should be to monitor, record, and report the sky temperature. / M.S.

All-day experimental tests were performed to determine the thermal performance of two commercial integral storage collectors for solar domestic hot water systems. These tests were performed under a variety of ambient conditions and irradiance levels, both with and without forced circulation and noontime hot water draws. An analytical model was developed to predict the thermal performance of one of the two systems tested and predicted performance was compared with experimental results. Experimental and analytical results indicate that thermal stratification has a mininal effect on the daily collection efficiency of integral storage collector, so that a standard test similar to ASHRAE Standard 93-77 might reasonably be used to obtain the performance characteristics of the collection element of these systems. The results of an ASHRAE 93-77 type test might then be used to obtain performance ratings under ASHRAE Standard 95 procedures using an in-line heat source. The results of the present investigation may be used to validate such an ASHRAE 95 test method. / Master of Science

This study presents a comparison of field measurements of energy delivered by five integral collector storage (ICS) passive solar water heater systems installed at various geographic locations in Virginia to predicted values calculated using Annual Performance Methodology (APM). APM is a prediction method developed by Alan Zollner that offers quick and easy comparisons of design option for ICS systems. Several different methods exist today that are meant to predict the performance of this type of system and that might be used as a design tool to help a designer make appropriate design decisions. Some of these methods are quite complicated and do not lend themselves to quick and easy comparisons of various design options. This study measured the amount of energy delivered by five ICS systems over a six month period. The amount of water drawn out of these systems daily was also recorded. This data was compared to predicted values calculated using APM to determine if APM could predict the performance of these systems within plus or minus 15 percent of the measured values. This study demonstrates that APM was able to predict long term performance of ICS systems within plus or minus 15 percent eighty percent of the time. Short term performance however demonstrated variation that in some cases were quite large and could not be considered reliable predictions. / M. Arch.

Residential water heating is linked to the primary source of waterborne disease outbreaks in the United States, and accounts for greater energy demand than the combined water/wastewater utility sector. To date, there has been little research that can guide decision-making with regards to water heater selection and operation to minimize energy costs and the likelihood of waterborne disease. We have outlined three types of systems that currently dominate the marketplace: 1) a standard hot water tank with no hot water recirculation (STAND), 2) a hot water tank with hot water recirculation (RECIRC), and 3) an on-demand tankless hot water system with no hot water recirculation (DEMAND). Not only did the standard system outperform the hot water recirculation system with respect to temperature profile during flushing, but STAND also operated with 32 – 36% more energy efficiency. Although RECIRC did in fact save some water at the tap, when factoring in the energy efficiency reductions and associated water demand, RECIRC actually consumed up to 7 gpd more and cost consumers more money. DEMAND operated with virtually 100% energy efficiency, but cannot be used in many circumstances dependent on scaling and incoming water temperature, and may require expensive upgrades to home electrical systems. RECIRC had greater volumes at risk for pathogen growth when set at the lower end of accepted temperature ranges, and lower volumes at risk when set at the higher end when compared to STAND. RECIRC also tended to have much lower levels of disinfectant residual (40 -850%), 4-6 times as much hydrogen, and 3-20 times more sediment compared to standard tanks without recirculation. DEMAND had very small volumes of water at risk and relatively high levels of disinfection. A comparison study of optimized RECIRC conditions was compared to the baseline modes of operation. Optimization increased energy efficiency 5.5 – 60%, could save consumers 5 – 140% and increased the disinfectant residual up to 560% higher disinfectant residual as compared to the baseline RECIRC system. STAND systems were still between 3 – 55% more energy efficient and could save consumers between $19 - $158 annual on water and electrical costs. Thus, in the context of “green” design, RECIRC systems provide a convenience to consumers in the form of nearly instant hot water, at a cost of higher capital, operating and overall energy costs. / Ph. D.

Thesis (MPhil)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: South Africa is facing an energy crisis on two levels; the existing capacity to supply electricity is unable to support future growth in demand, and the electricity being produced comes mostly from coal-fired power stations with associated emission problems. The South African government has a target for renewable energy to service 23% of the country’s energy consumption by 2013. This could potentially be realised through achievement of another government target, the installation of one million Solar Water Heaters (SWHs). On a technical level, Solar Water Heaters (SWHs) represent a completely viable renewable energy alternative for South Africa. It is an established and proven technology which has the potential to have a big impact on the country’s electricity capacity problems. SWHs can be used in a variety of applications from industry to households. Most of the hot water in South African homes is heated by electric resistance heating in standard electric water heaters and there are no technical obstacles to replacing most of these with SWHs, thereby delivering a saving of up to 70% of the water heating energy bill. Water heating currently accounts for 40% of domestic electricity consumption within a residential sector that uses 20-30% of the national supply. At the macroscale, the roll out of SWH programmes is completely scalable. The benefits of SWH installation accrue to the consumer in the form of a financial saving in the long-term and to society in the form of reduced emissions. Awareness of the benefits is growing amongst the general public, commercial institutions and in government. Sales are starting to pick up due to, amongst other reasons, electricity price hikes and government subsidies for SWH installations offered through the national electricity supply company, Eskom. A national building regulation enforcing energy-efficient water heating in new buildings has been drafted and is expected to be in place by mid 2011. The rate of change from electric to solar water heaters remains disappointingly slow, however. The SWH industry in South Africa accounts for less than 10% of total hot water solutions sold. This study sought to establish the opportunities as well as possible barriers for the creation of SWH programmes within the insurance sector. Close to 50% of all standard electric water heaters installed in South Africa are procured and installed via the insurance industry due to the failure of units that have endured beyond the manufacturer’s guarantee period. This presents an opportunity for interventions that encourage policyholders to change to SWHs. Such interventions, if successful, would dramatically speed up the roll out of SWHs in South Africa. In addition the study sought to determine the barriers to the uptake of SWHs by policyholders in the case of the two insurance companies that currently have SWH programmes in operation. Data was collected through interviews with representatives in the insurance industry and a range of SWH industry stakeholders and consumers. The literature review focused on SWH policies and regulations and corporate and marketing theories. The material on transition in socio-technological systems proved especially useful in understanding the complex dynamics of the study topic. The conclusion drawn from the research is that the South African insurance industry has the capacity and opportunity to drive the penetration of SWH technology. The opportunity is, however not being exploited to anywhere near its potential. The entire system is geared towards providing a particular ‘business-as-usual’ solution. Analysis conducted in this study confirms that the system is in a “locked-in” state and extremely resistant to change. If the opportunity is to be acted on, to supplant the dominant technology for water heating installed by the insurance industry with what is currently a niche technology (SWHs), an external landscape shock is almost certainly needed. This shock to the system could be aided by interventions that target a change in the current system’s logic. The study provides some suggestions in this regard. / AFRIKAANSE OPSOMMING: Suid-Afrika staar ‘n energie krisis in die gesig. Aan die een kant is die bestaande elektrisiteitsvoorsiening nie genoeg om plek te maak vir die toekomstige vraag na elektrisiteit nie en aan die ander kant word meeste van Suid-Afrika se elektrisiteit opgewek deur steenkoolaangedrewe kragstasies met gevolglike probleme as gevolg van vrylating van kweekhuis-gasse. Die Suid-Afrikaanse regering het ‘n teiken vir hernubare energie om 23% op te maak van die land se totale energie verbruik teen 2013. Hierdie teiken sou potensieel bereik kon word deur die bereiking van ‘n ander van die land se teikens, naamlik die instalering van een miljoen sonverhitters. Op ‘n tegniese vlak verteenwoordig sonverhitters ‘n lewensvatbare hernubare energie alternatief vir Suid-Afrika. Dit is ‘n beproefde tegnologie wat die potensiaal het om ‘n groot impak te hê op die elektrisiteit kapasiteitsprobleme van die land. Sonverhitters kan ‘n verskeidenheid van warm water behoeftes bevredig, van groot industrieë tot tuisverbruik. Meeste warm water in Suid-Afrikaanse huise word verhit deur standaard elektriese geisers. Daar bestaan geen tegniese hindernisse om hierdie geisers deur sonverhitters te vervang en tot 70% van die water verhittings energie rekening te bespaar nie. Water verhitting maak tans 40% van die totale huishoudelike elektrisiteits verbruik op. Die huishoudelike verbruik is 20-30% van die nasionale verbruik en selfs hoer gedurende piek. Op die makro skaal is die uitrol van sonverhitters heeltemal skaleerbaar. Die voordele van die installering van sonverhitters val die verbruiker toe in die vorm van finansiele besparing oor die lang termyn en vir die samelewing as geheel in die vorm van emissie besparings. Bewustheid van die voordele is aan die groei by die algemene publiek, kommersiele instansies en by die regering. Verkope het begin optel as gevolg van onder andere die elektrisiteits prysverhoging en die staatssubsidies vir sonverhitters aangebied via die nasionale elektrisiteits toevoer maatskappy, Eskom. A nasionale bouregulasie wat enegie doeltreffende waterverhitting sal afdwing op nuwe geboue is reeds opgestel en dit word verwag dat hierdie regulasie in plek sal wees teen middel 2011. Die koers van verandering van elektriese water verhitters na sonkrag bly egter teleurstellend laag. Die sonverhittings industrie in Suid-Afrika maak minder as 10% van die totale water verhittings mark uit. Hierdie studie het beoog om die geleenthede sowel as die moontlike versperrings tot die skepping van sonverhittings programme in die versekerings bedryf uit te wys. Die versekerings bedryf koop en installeer ongeveeer 50% van alle standaard elektriese geisers in Suid-Afrika as gevolg van elektriese geisers wat breek na die vervaardiger se waarborg verval het . As gevolg hiervan bestaan daar ‘n geleentheid vir intervensies wat polishouers aanmoedig om te verander na sonverhitters. Sulke intervensies, indien suksesvol, het die potensiaal om die uitrol van sonverhitters in die land dramaties te versnel. Verder het hierdie studie beoog om die versperrings tot die opname van sonverhitters uit te wys by twee versekerings maatskappye in Suid-Afrika wat wel sonverhittings programme het. Data is versamel deur onderhoude met verteenwoordigers van die versekeringsbedryf en ‘n reeks sonverhitting industrie belanghebbendes en verbruikers. Die literatuurstudie het gefokus op sonverhittings beleid en regulasies en korporatiese en bemarkings teorie. ‘n Literatuurstudie in oorgang in sosio-tegnologiese sisteme was veral nuttig om die komplekse dinamika van die sisteem te verstaan. Die gevolgtrekking van hierdie studie is dat die Suid-Afrikaanse versekeringsbedryf wel die kapasiteit en geleentleid het om die penetrasie van sonverhittings tegnologie te dryf. Hierdie geleentheid word egter nie gebruik tot sy volle potensiaal nie. Die ganse sisteem is gerat om ‘n spesifieke tegnologie op ‘n sekere manier te verskaf. Analise in hierdie studie bevestig dat die sisteem in ‘n geslote staat is en daar is uiterste teenkanting tot verandering. Indien hierdie geleentheid om die dominate tegnologie vir waterverhitting geinstaleer deur die versekerings bedryf te verplaas met wat op die oomblik nog ‘n niche tegnologie is (sonverhitters), is ‘n eksterne landskap skok nodig. Hierdie skok tot die sisteem kan aangehelp word deur intervensies wat ‘n verandering in die huidige sisteem logika teiken. Hierdie studie bied ‘n paar voorstelle in hierdie verband.

Thesis (MBA)--University of Stellenbosch, 2011. / The government has stated its intentions to increase the usage of solar water heating (SWH) through its National Solar Water Heater Programme (NSWHP). As described in the report, increased adoption of SWH would have a number of benefits for South Africa. Firstly, replacement of electric geysers by SWHs would contribute to the meeting of energy efficiency targets through the reduction of energy consumption. Secondly, the widespread adoption of SWHs would help SA to meet its renewable energy targets. Thirdly, it would result in growth in the SWH industry, including the manufacturing, installation and related sectors, thereby contributing to an increase in 'green' jobs. It would have the socio-economic benefit of energy security for South Africans. The research report looks at the factors influencing the SWH industry's future growth from the point of view of the suppliers. It considers the interplay between consumers (market demand), government (public policy measures) and suppliers (businesses providing services related to SWH) to determine how government can support industry, how suppliers can grow their business and industry and how government and industry can work together to create the conditions for sustained market demand. As is discussed in the literature review, there are certain barriers to the adoption of SWH technology. As such, government intervention is needed to help overcome these barriers. The literature review recounts the available policy tools and considers how these have been applied in other countries to stimulate demand for SWHs and to support the local industry. The research report takes the form of a survey of SWH suppliers with the following aims: - To describe the industry in terms of its age, maturity and ability to scale up; - To determine the major barriers to the industry's growth; - To specify the appropriate public policy tools to overcome these obstacles to growth; - To establish how confident the industry is in the NSWHP and government efforts to promote the industry; - To provide a list of key success factors that are required for the industry's long-term, sustainable development. The report concludes that there are three criteria that would help the industry to become sustainable: market demand certainty, investment confidence and positive competition. Certainty of future market demand would build confidence in the industry for investors. In turn, increased investment would benefit the forces of positive competition.