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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

The impact of solar water heaters on sustainable development

Mbeng, Regina Nso January 2014 (has links)
In this present world order of growing information, communication and technological advancement, it is primordial that climate change adaptation and mitigation efforts seeks to make people resilient to inevitable climate inconsistency through the exploitation and development of renewable energy sources. Though climate impacts are global, the population most at risk is predominantly from developing countries, particularly poor communities who have experienced multi-layered threats from floods, droughts and energy supply, just to mention a few. This explains why sustainable development is at the heart of all development trajectories in the world today, specifically the post-2015 development tenets. Climate change adaptation and mitigation requires international collaboration from all nations in order to get an effective and unified response to climate change. Building a critical mass for action and an institutional memory to sustain policies and efforts is crucial. A resilient-based approach to climate mitigation and adaptation founded on a crisis-driven reaction to communities vulnerable to climate threat will boost quality of life through the provision and safeguarding of safety nets for the poor. Solar water heaters, a renewable energy source, are here considered as a critical option to South Africa’s coal-driven economy as a means of alleviating energy poverty in rural and low-income communities, to be more precise. Therefore, SWHs have become the epicentre of sustainable development policies and climate change mitigation efforts in South Africa. So far, this device has attracted the attention of local governments in the country who view it as a game changer in the field, particularly towards greenhouse gas emission and energy conservation. The contour of this thesis is to assess the impact of solar water heaters on sustainable development. Although it is generally difficult to assess the real impact of technology on people, that of SWHs was established by asking questions about livelihood before, during and after the introduction of this device.
32

An evaluation of a magnetic physical water treatment device for the prevention of scale fouling in hot-water storage tanks

Smith, Christo 06 December 2011 (has links)
M.Ing. / Scaling problems in a heating or cooling system can be recognised by one or more of the following symptoms. Reduction in heat transfer rate, in which the formation of an insulating deposit on a heat transfer surface significantly reduces the cooling or heating efficiency of the equipment. Reduced water flow, which results from a partial or complete blockage of pipelines, condenser tubes, or other openings. Even a small build-up of scale on a heat exchange surface reduces water flow. Scale may continue to build up in boilers until heat transfer is so low that the metal overheats, permitting the tubes to rapture under the operating pressure. Scale is usually found in water-handling equipment in which water is heated, i.e. hot-water storage tanks, boilers, etc. The magnitude of this problem may be appreciated by considering that scaling can cause degradation, or complete failure in thermal and hydraulic performance which increases initial and operating costs (Chan and Ghassemi, 1991). A fairly low-pressure boiler, with only 0.6 mm of calcium sulphate scale on the tubes results in a 180°C temperature drop. The cost involved due to heat transfer inefficiency and the removal of scale, in Britain alone, is estimated at £1 billion per annum (Darvill, 1993). Poor conductivity of a 25 mm thick CaC03 scale layer can decrease the heat transfer by 95% (Glater eta/., 1980), whereas a Si02 scale layer 0.5 mm thick results in a 90% decrease in heat transfer (Grutsch and McClintock, 1984).
33

Methodology to Measure and Compare the Efficiency of Radiant Heaters Used in Poultry Brooding

Linhoss, John Emerson 12 August 2016 (has links)
During the first seven to ten days of life chicks are unable to maintain homeothermy, thus providing supplemental heat is critical to their livability and performance. Radiant heaters are the preferred method of providing heat during brooding because they provide a range of thermal comfort options for chicks. Infrared thermography is often used to assess the heat distribution created at the litter surface by radiant heaters. The resulting images provide a good qualitative assessment of heat distribution but do not provide any quantifiable metrics through which to compare the radiant output of heaters. Data acquisition systems were developed to measure the radiant flux emitted by six 11.72 kW radiant heaters and to determine radiant flux ranges preferred by broiler chicks during the first week of brooding. Results showed the radiant output was influenced by heater elevation above the litter and differed between manufacturers. 21 – 41% of the energy available the heaters was emitted to the litter as radiant heat. Chicks exhibited a decreasing preference for radiant flux with age. Maximum preferred radiant flux decreased from 387.0 W·m-2 at day 1 to 248.3 W·m-2 at day 8, while the minimum preferred radiant flux decreased from 61.2 W·m-2 at day 1 to 7.65 W·m-2 at day 8. Net usable area (NUA), or the total floor area within the range of radiant fluxes preferred by chicks, was calculated for each heater. Mean NUA by heater ranged from 45.34 (SE = 3.35 m2) to 21.75 (SE = 1.98 m2). Mean NUA significantly increased with heater mounting elevation (P < 0.0001). Results indicate that radiant heaters from different manufacturers with the same power output do not necessarily produce the same radiant distribution and that the maximum preferred radiant fluxes by chicks may not be realized at manufacturer specified heater mounting elevations.
34

Design and validation of a solar domestic hot water heating simulator

Cemo, Thomas A. Van Treuren, Kenneth W. January 2009 (has links)
Thesis (M.S.M.E)--Baylor University, 2009. / Includes bibliographical references (p. 133-134).
35

Utilização de procedimentos multivariados no consumo de água e energia elétrica em habitações sociais com sistema de aquecimento solar /

Tutia, Marcelo Hiroshi, 1977. January 2015 (has links)
Orientador: Carlos Roberto Padovani / Banca: Osmar de Carvalho Bueno / Banca: Paulo André de Oliveira / Banca: Rogério Antonio de Oliveira / Banca: Marie Oshiiwa / Resumo: Atualmente, fontes de energia renováveis são exploradas e usadas para o desenvolvimento da sociedade e se destacam por serem mais limpas e menos poluentes que as fontes de energia não renováveis. Entre estas fontes de energia renováveis, a energia solar é uma das mais aproveitadas, usada em sistemas fotovoltaicos para geração de energia elétrica e em sistemas de aquecimento solar de água, sendo a segunda utilização citada a mais conhecida, podendo ser vista em residências, comércios e indústrias. O sistema de aquecimento solar tem entre seus objetivos, o de proporcionar economia de energia elétrica, pois fornece água quente sem a necessidade de utilizar sistemas elétricos, como o chuveiro elétrico, que é um dos aparelhos que mais consome energia. Para proporcionar economia do consumo de energia elétrica, minimizar impactos ambientais, redirecionar investimentos em novas fontes geradoras de energia elétrica, o Governo do Estado de São Paulo, em conjunto com a Companhia de Desenvolvimento Habitacional e Urbano do Estado de São Paulo - CDHU, como política de habitação, instalaram, nas residências de interesse social construídas a partir de 2007, o sistema de aquecimento solar de água. Na cidade de Ourinhos - SP, o conjunto habitacional Helena Braz Vendramini foi contemplado pelo sistema de aquecimento solar de água nas residências, porém, na mesma cidade, existe outro conjunto habitacional, o Orlando Quagliato, mas, por ser mais antigo, não possui o sistema de aquecimento solar, fator que motivou o presente estudo quanto à busca de determinantes para a viabilização e recomendação de características fundamentais para a otimização do aproveitamento de fonte de energia alternativa. O objetivo desta pesquisa foi aplicar procedimentos e técnicas de análise multivariada na avaliação do impacto econômico e na busca dos identificadores socioeconômicos fundamentais ... / Abstract: Nowadays, renewable energy sources are exploited and used for the development of society and stand out for being cleaner and less polluting than non-renewable energy sources. These renewable energy sources, solar energy is one of the most exploited, used in photovoltaic systems for power generation and solar water heating systems, the second use cited the best-known and can be seen in homes, businesses and industries. The solar heating system has among its objectives, to provide energy saving because it provides hot water without the need for electrical systems, such as electric shower, which is one of the devices that consume more energy. To provide economy of energy consumption, minimize environmental impacts, redirect investments in new sources of electricity, the Government of the State of São Paulo, together with the Development Company Housing and Urban State of São Paulo - CDHU, as housing policy, installed in homes of social interest built from 2007, the solar heating system water. In Ourinhos - SP, Helena Braz Vendramini housing project was awarded the solar heating system water in homes, but in the same city, there is another housing project, the Orlando Quagliato, but being older, does not have the solar heating system, a factor that motivated this study and the search for determinants for the viability and recommendation of key features to optimize the alternative energy source to use. The objective of this research was to apply procedures and techniques of multivariate analysis in evaluating the economic impact and the pursuit of fundamental socioeconomic identifiers for the description of a rational use of water policy and energy in housing with and without solar water heating system. The results showed that differences between the housing are observed for combinations of consumption and socioeconomic variables and the association of positivity between these sets of variables was... / Doutor
36

Solar water heating and its impact on the energy demand in Botswana.

Mpaesele-Motsumi, Malebogo. January 2013 (has links)
M. Tech. Electrical Engineering. / Discusses the study objectives as follows: 1. Description of the extent of roll-out of SHW (Solar Water Heater) as a DSM (Demand Side Management) Programme in Botswana. 2. Identification of SWH implementation obstacles/barriers in Botswana. 3. Provision of a strategy for SWH data capture and verification in Botswana. 4. Evaluation of SWH performance through field measurements. 5. Prediction of SWH performance results using performance predictive simulation models. 6. Extrapolation/quantification of the impact of SWH. 7. Provision of energy management/planning/forecasting tool.
37

Solar water heating : reducing the barriers.

Naicker, Jayson Shirinivasan. January 2010 (has links)
There is the potential to use solar energy as an energy efficient method of heating water, instead of using electricity. This study investigated the current barriers to the mass rollout of solar water heaters in South Africa and provided possible solutions to reduce these barriers. Local experts have already identified the key barriers to the rollout of solar water heaters and this study drew from the findings of international practises and applied these findings to the South African context. The barriers that are preventing the industry from developing are: the high price of solar water heaters, the lack of awareness of the technology, the absence of legislation, a tedious process for rebates, non–mandatory standards, insufficient training facilities leading to a shortage of skills and the low price of electricity. The research methodology was a blend of qualitative and a quantitative study including relevant theory supported by seven open-ended questionnaires completed by recognised industry specialists. The information gathered from the questionnaires was analysed and compared to the theory and international experience. The barriers to solar water heating can be overcome by having more government involvement in the development of policies to promote and educate the public on alternative energy sources. This lack of awareness on the technology can be improved by having awareness programmes in schools and frequent broadcasts on radio and television. There is a dire need for the development of cost effective financing mechanisms because the high costs of production influences the price of solar water heaters. Financial incentive models such as rebates, could be more effective in assisting the low and middle-income groups with partial funding for the purchase of the solar water heater. / Thesis (MBA)-University of KwaZulu-Natal, 2010.
38

The use of solar water heaters in Mexico City /

Ferrel-Mendieta, Minerva. January 1999 (has links)
During the last decade, Mexico City's air quality has deteriorated dramatically. Air pollution management has become a major issue, and a number of policies and campaigns aimed at reducing the volume of harmful emissions released into the atmosphere by vehicles and large-scale industries, have been implemented. / Lighting, office equipment, cooking, refrigeration, space heating, space cooling, ventilation, and water heating are the ultimate commercial uses of energy. The goal of this study is to determine if there is a potential market for solar water heaters that could provide hot water for a number of activities in the city, reducing the amount of fossil fuels burned for this purpose, thus contributing to decrease the amount of air pollutants to the atmosphere. / The results of this research show how a number of industries, public services and commercial activities need to be provided with both water and energy in large quantities, and are therefore potential users of solar thermal technologies.
39

Computational design of a smart and efficient control system for a residential air source heat pump water heater

Yongoua Nana Joel January 2017 (has links)
An air source heat pump (ASHP) water heater is a renewable and energy efficient hot water heating technology. ASHP water heaters are fast gaining maturity in the South African market and in Africa at large due to their low energy consumption (about 67 percent lower than conventional geysers), relatively low installation and operation cost, their environmental friendly nature and possibly the ease to retrofit with the old inefficient technologies. Furthermore, ASHP water heaters make use of some of the most recent advancement in refrigeration technologies enhancing their performance through a wide range of weather conditions. However, residential ASHP water heaters which come at the tail of a series of highly sophisticated models still harbour primitive control designs. One of such control system is the intermittent (on/off) control whereby the ASHP unit responds to a temperature differential threshold rather than instantaneous temperature fluctuations. Unfortunately, this control method contributes to a rapid deterioration of the compressor and other actuators due to high starting current during transient states and partial loading. Capacity control is a better alterative as it offers a more reliable system’s performance as well as a better protection for the system components. However, the drawbacks of implementing such a technology on residential ASHP water heaters is the initial purchasing cost. We use a systematic approach in this research to circumvent the purchasing cost and complete redesign hysteresis. The first step was centered around a hypothetical analysis of the performance of the heat exchangers in a bid to uncover the weakness during the operation of a residential ASHP water heater. It was observed that at ambient temperatures above 22°C notably during summer and winter afternoons, water only harnesses about 75 percent of the total heat rejected. Furthermore, the actuators keep doing work for about 15-20 minutes even after the heat transfer process has ceased completely. Following these observations, a sequential flow algorithm was developed aimed at matching the consumption point to weather variables like ambient temperature and secondly to most efficiently synchronize actuator components for a better energy management. This novel control method can save up to 58 percent of energy compared to the conventional on/off method during summer afternoons and averagely 20 percent during the rest of the day. It also has the merit to be cost effective as it barely requires no component retrofitting.
40

Performance of a residential swimming pool air source heat pump water heater installed in Fort Beaufort, South Africa

Mqayi, Singatha January 2017 (has links)
Globally, there is growing concern about energy consumption and its diverse effects on the environment. In South Africa, the current status quo is unfavourable in the domain of energy, hence the Department of Energy, Eskom and NERSA have embarked on supporting energy efficiency technologies nationwide as a strategic goal in reducing demand on the national grid. Due to the non conservative consumption of electricity from the grid and the insufficient supply to meet its demand, the importation of crude oil is very certain. In addition, the current and most popular technology for pool water heating in the said country is the resistive element which is inefficient and non-cost-effective. The energy consumption of residential swimming pool water heating is very massive, and tariff structure shows a constant rise. Furthermore, there's a current electricity crisis during the Eskom evening peak. Hence, a reliable, efficient, cost-effective and renewable energy technology such as an air source heat pump is required as a retrofit to the existing resistive element. Furthermore, mathematical modelling is a tool that can be used to mimic the dynamic behaviour of a physical or process system. It is a computational language or mathematical equation used to predict the dynamic behaviour of physical systems [Tangwe et al., 2015]. Various methods such as numerical methods have been considered as the particular types of mathematical modelling which have been employed to predict the performance of swimming pool ASHP water heater. However, they were unreliable and expensive. Consequently, this research focused on the experimental determination of the viability and development of a mathematical model to predict the performance of swimming pool ASHP water heater. The benefit of the development and building of this model was attributed to its low cost and credibility to forecast the performance of swimming pool ASHP water heater. Also, this robust mathematical model can be used by an energy service company and system manufacturer to compute the dynamic coefficient of performance of the swimming pool ASHP water heater. Following the above-mentioned information, the research sought to provide a permanent solution to the Eskom evening peak constraint. This is because energy-efficiency, serves as the bridging block between conventional and renewable energy sources needed by Eskom in a bid to provide a balance energy mix and sustainable energy. The implementation of a swimming pool ASHP water heater guaranteed a conducive environment for the population due to the reduction in environmental pollution.

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