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).

Thesis (M.S.M.E)--Baylor University, 2009. / Includes bibliographical references (p. 133-134).

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

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.

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.

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.

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.

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.

Made available in DSpace on 2015-08-20T17:10:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-06. Added 1 bitstream(s) on 2015-08-20T17:25:42Z : No. of bitstreams: 1 000843148.pdf: 1252440 bytes, checksum: 0bb257659edd87f44be9d42ef4f29481 (MD5) / 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 ... / 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...

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016. / Solar energy is still not being used effectively in countries in the developing world, though it's a partial solution to the problem of shortage and expensive energy. Normally harvested through flat plate collectors, converting solar radiation into heat is the most direct application that can be effected in water heating systems. Many researchers have attempted to develop means of improving the efficiency of the flat plate solar energy collector; however there appears to be no evidence of any work regarding the effect of geometric configuration on the performance of flat plate solar collector. This study presents results obtained when comparing the performance of a solar water heating system equipped with three manufactured flat plate solar collector panels of numerically identical surface area but of different geometric configuration as they were individually attached to a typical geyser. Data was obtained inside a laboratory. The amount of heat acquired from flat plate collectors of solar energy depends primarily on their surface area that is exposed to the solar irradiance, however, the geometry of the collectors was thought that it might affect to some extent the amount of heat harvested. The circulation of the water from the panel to the geyser was due to the self-induced thermo-syphon effect. The results obtained during the test period (7 hours per day for two consecutive days) indicated that the system’s thermal efficiency was best when the square geometrical configuration collector was used. A dimensional analysis using the Π Buckingham method that was performed on the parameters affecting a flat plate solar collector yielded three dimensionless numbers that lead to a power law relationship which might be useful in enhancing solar water heating systems’ design.