31 |
Renewable energy : benefits of converting urban households to solar water heatingCovary, Theo 30 March 2010 (has links)
Modern man’s addiction to fossil fuels or non-renewable energy is the key reason behind the unprecedented economic growth experienced globally over the past 100 years. However, by definition these energy resources are not only finite, but their widespread use is causing massive environmental damage through air pollution and its associated impact on people’s health, as well as the emission of greenhouse gases which are attributed to the unprecedented rate of global warming - And it is for this reason that international initiatives such as the Kyoto Protocol, (which South Africa is a signatory of), aim to mitigate global warming by reducing member countries’ CO2 emissions.Simultaneously, South Africa (SA) is experiencing its own electricity supply problems due to under investment in the sector. While new power plants are being built, they utilize non-renewable energy sources and will take time to build (up to 5 years). It is also important to note that due to large coal reserves, South Africans enjoy amongst the lowest electricity tariffs in the world, but SA is amongst this planet’s biggest per capita polluters.The research thus aims to identify whether high income households are wasteful users of electricity - due to historic low prices, lack of knowledge regarding energy efficiency and the impact that electricity generation has on the environment - while at the same time determining the group's perception of domestic solar water heaters (DSWH), given our country’s favourable climaticconditions. / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted
|
32 |
An innovative application of nuclear magnetic resonance technology to complex flowsHong, Jiaju January 2016 (has links)
In the present work, an inter principle research is carried out on complex fluid flow and heat transfer, using an innovative technology Nuclear Magnetic Resonance (NMR), from the Department of Physics. To enhance heat transfer performance of complex fluid flow, the present work mainly focuses on two different parts, one is the adoption of nanofluid; the other is flow forces analysis through bionic engineering studies on plant water migration system. Nanofluids are attracting considerable attention from both academic and industrial communities. Comparing with conventional pure fluids or solutions, nanofluids have higher thermal conductivity, due to the high surface to volume ratio of nanoparticle and liquid interface, which exhibits a great potential in enhancing heat transfer performance in various occasions. It is believed that different types and concentrations of nanofluid could strongly affect the thermal performance, and a great number of papers have been published to illustrate the phenomenon. However, none has really focused on the possible concentration change of nanofluid while flowing. Otherwise, the thermal performance of nanofluid flow could never be quantified. In the present work, a novel method to measure the dynamic concentration of nanofluid is proposed, using NMR technology. The experiments were carried out with ferrofluid under different concentration and temperature. A new parameter T2* was introduced in the study. T2* is a relaxation time of the signals that is released by hydrogen atoms after Radio Frequency (RF). And this signal intensity can be strongly affected by nanofluids. Experiments were carried out to obtain the T2* of nanofluid in the pipe. An empirical equation based on T2* and temperature was proposed to calculate the concentration of nanoparticles. Then, experiments were carried out with flowing ferrofluid in pipe. The dynamic concentration was calculated with the empirical equation. And with the series of experiment, it is confirmed that the flowing nanofluid consists of an obvious concentration gradient, and thus cause different layers of thermal performance from boundary to central line of a laminar pipe flow. Furthermore, the experiment result also gives out a chance to investigate the mechanism of nanoparticle movement in laminar flow with the concentration gradient along radius. Bionic Engineering is another research field that has been more and more interesting to researches from various fields. Since life has been evolving for over millions of years, many functions in lives has become extremely high efficiency and adaptive. These functions can be very worthy for researchers to study and utilize in industries. For heat transfer in fluid flow, it is very important to enhance the flow pattern. And thus water migration system in plants become very attractive. Plant can take water from soil up to several metres high. Learning from the water migration process in plants has been attracting interests from scientist for over a hundred years. The water migration in plant stem, especially xylem, involves various driving forces including capillary effect, osmosis effect, Marangoni effect and transpiration effect, etc. This present work mainly focuses on the water transport process within xylem. As xylem system is simplified as micro channel, a mathematic model is presented based on micro channel theory, with critical analysis and simplification. With a simplified micro channel from xylem structure and the calculation using the model of water migration in xylem, the relationship between various forces and water migration velocity is identified. The velocity of water migration within the plant stem is considered as detail as possible using all major forces involved. And a full mathematical model is proposed to calculate and predict the velocity of water migration in plants. Comparison between the calculated result and experimental one is made, to confirm the accuracy of the mathematical model. The present work proved that the mathematical model should be enough to predict the water migration in plants, and could also be critical for future water transport prediction in complex fluid flow in industry applications such as heat pipe.
|
33 |
Infield Biomass Bales Aggregation Logistics and Equipment Track Impacted Area EvaluationNavaneetha Srinivasagan, Subhashree January 2017 (has links)
Efficient bale stack location, infield bale logistics, and equipment track impacted area were conducted in three different studies using simulation in R. Even though the geometric median produced the best logistics, among the five mathematical grouping methods, the field middle was recommended as it was comparable and easily accessible in the field. Curvilinear method developed (8-259 ha), incorporating equipment turning (tractor: 1 and 2 bales/trip, automatic bale picker (ABP): 8-23 bales/trip, harvester, and baler), evaluated the aggregation distance, impacted area, and operation time. The harvester generated the most, followed by the baler, and the ABP the least impacted area and operation time. The ABP was considered as the most effective bale aggregation equipment compared to the tractor. Simple specific and generalized prediction models, developed for aggregation logistics, impacted area, and operation time, have performed well (0.88?R2?0.99). An ABP of 8 bales capacity, also capable of 11 bales/trip, was recommended. / North Dakota State University. Teaching Assistant Scholarship
|
34 |
Estimating the performance of hybrid (monocrystalline PV - cooling) system using different factors.Zeinaldeen, Laith Akeelaldeen 01 December 2020 (has links)
AN ABSTRACT OF THE DISSERTATION OFLaith A. Zeinaldeen, for the Doctor of Philosophy degree in AGRICULTURAL SCIENCES – Renewable Energy, presented on November 2, 2020, at Southern Illinois University Carbondale.TITLE: ESTIMATING THE PERFORMANCE OF HYBRID (MONOCRYSTALLINE PV - COOLING) SYSTEM USING DIFFERENT FACTORSMAJOR PROFESSOR: Dr. Logan O. ParkAmbient temperature significantly affects photovoltaic (PV) panel performance. High temperature reduces PV panel efficiency, fill factor, and maximum power, driving up solar electrical system investment return period by increasing startup cost. Using a proper cooling system to cool down the PV panel temperature, especially during the summer season, will improve the PV panel performance, enhance its longevity, and accelerate the startup cost recovery to the solar electrical system. This dissertation presents two studies about monocrystalline PV panels. The studies used two general objectives: (i) study the best cooling period and water nozzle type to improve the monocrystalline PV panel output; and (ii) evaluating the performance of the monocrystalline PV panel using different cooling systems, other water pump discharge, and various water types during different times of day. In the first study (chapter 4), an experiment was conducted during July 2018 to determine Effect of using different cooling periods and different water nozzle types on the fill factor, efficiency, and the maximum power of monocrystalline PV panel. This experiment used two factors. The first factor was the cooling periods, which included three levels of PV panel cooling periods (5, 15, and 30 minutes). The second factor was water nozzle type: hollow cone and flat fan.In the second study (chapters 5, 6, and 7), an experiment was conducted during July and August 2018 to determine Effect of using different factors on the performance of monocrystalline PV panel at a site belong to the College of Agriculture – Southern Illinois University in Carbondale, IL. This experiment used four factors. The first factor was the time of day, the second factor was the cooling system, the third factor was the water pump discharge, and the fourth factor was the water type. The present studies' principal findings were: (i) the first experiment, the 15 minutes cooling period achieved the highest PV panel fill factor (0.795). In comparison, the 30 minutes cooling period reached the highest panel efficiency (18.6%) and maximum power (92.5 Watt). In contrast, the 5 minutes cooling period achieved the lowest PV panel fill factor (0.720), lowest panel efficiency (12.9%), and most insufficient panel maximum power (63.5 Watt). The hollow cone water nozzle achieved the highest panel fill factor (0.783), highest panel efficiency (16.60%), and the most elevated PV panel maximum power (82.8Watt). Interaction between the cooling and water nozzle types was non-significant on PV panel fill factor, significant on panel efficiency, and highly significant on PV panel maximum power. The interaction results between the cooling period and nozzle type demonstrate that the hollow cone nozzle with 30 minutes cooling period achieved the highest panel fill factor, highest panel efficiency, and the most elevated panel maximum power. The flat fan with a 5-minute cooling period achieved the lowest fill factor, lowest panel efficiency, and most insufficient panel maximum power. Tukey test results showed a highly significant difference (P < 0.0001) between the cooling period and the control treatment, and between the nozzle type treatment and the control treatment on panel fill factor, efficiency, and panel maximum power. Cooling periods have the most considerable effect on panel fill factor, panel efficiency, and maximum panel power, followed by the nozzle type. (ii) The second experiment results showed, the first cooling system (HC1) achieved the highest PV panel maximum power (77.0Watt), highest fill factor (0.745), highest PV panel efficiency (14.75%), highest average net energy (39.5Wh), highest PV panel energy (189.0 Wh) and highest average power gain (34.6Watt) comparing to the rest of the cooling systems. In comparison, the fourth (FtF2) achieved the lowest maximum power (58.0 Watt), lowest fill factor (0.653), lowest average efficiency (11.6%), lowest average net energy (-4.0Wh), lowest average energy (147.5Wh), and lowest average power gain (17.5 Watt). The fifth cooling system (SP) achieved the least average water consumption (2.0 L / hr.), while the second cooling system (HC2) achieved the highest average water consumption (39.0 L / hr.). The medium water pump discharge (M) produced the most elevated PV panel maximum power (67.6 Watt), highest fill factor (0.709), highest average PV panel efficiency (13.28%), highest average PV panel net energy (18 Wh), highest average PV panel energy (169.0Wh) and the highest average PV panel power gain (25.9Watt). High water pump discharge (H) achieved the lowest maximum power (63.8Watt), lowest average panel efficiency (12.48%), lowest average net energy (7.5Wh), lowest average panel energy (159.5Wh), and the lowest average power gain (21.8 Watt). The low water pump discharge (L) achieved the lowest panel fill factor (0.698). Lake water achieved the highest panel maximum power (66.1Watt), lowest PV panel fill factor (0.698), highest panel efficiency (12.94%), lowest net energy (12.8 Wh), highest panel energy (165.2 Wh), and lowest power gain (23.5Watt). In contrast, city water achieved the most elevated PV panel fill factor (0.708), most insufficient panel maximum power (64.8 Watt), highest average PV panel net energy (14.8 Wh), lowest efficiency (12.62%), highest average PV panel power gain (24.25 Watt) and lowest panel energy (162.1 Wh). Tukey post hoc difference testing showed highly significant differences (P < 0.0001) between the time of day, cooling system, water pump discharge, water type treatments, and their control treatment on PV panel maximum power, fill factor, panel efficiency, panel net energy, panel energy, power gain, and the system water consumption. The cooling system has the most considerable effect on PV panel maximum power, panel fill factor, panel efficiency, panel net energy, panel energy, panel power gain, and the system water consumption. In general, using the cooling system improves the PV panel performance through enhancing the PV panel efficiency, maximum panel power, panel fill factor, panel net energy, panel energy, and PV panel power gain. Keywords: Cooling system, cooling periods, water pump discharge, water type, time of day, efficiency, maximum power, fill factor, net energy, panel energy, PV panel power gain, and cooling system water consumption.
|
35 |
LOCALIZED FLOW MODIFICATION TO INCREASE POWER CAPTURE OF A SMALL-SCALE FLOATING UNDERSHOT WATERWHEELUnknown Date (has links)
The goal of the work described in this thesis is to design a flow augmentation device to increase the power capture and efficiency of a small-scale floating Under-Shot Water Wheel (USWW) currently being developed by Florida Atlantic University research funded by the U.S Department of Energy. The flow concentrator subsystem is intended to maximize the kinetic energy extracted by the marine hydrokinetic (MHK) energy collection device through modification of the local flow field across the capture plane. The primary objective is to increase the velocity and/or rate of mass inflow through the turbine through inserting a streamlined body in the region of interest. By utilizing the resulting flow field to increase hydraulic forcing on the waterwheel blades, the torque and/or RPM of the USWW can be increased. Based on experimental testing in the FAU wave tank at 1:5 prototype scale (280 mm wheel diameter) the flow concentrator was shown to produce an increase in device power coefficient of 17-55% measured over a velocity range of 0.16-0.45 m/s. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection
|
36 |
The future of energy in Mississippi: policy and politicsFowler, Nicholas Luke 08 August 2009 (has links)
This study analyzes the elements surrounding renewable energy development in Mississippi, with emphasis on the aspects related to government intervention. This study addresses the question: how can energy policy in the state of Mississippi support a transition from fossil fuels to non-traditional sources of energy? Drawing from existing literature, renewable energy was analyzed on the cost, development, and environmental concerns, while GIS analysis was utilized to determine generation capacity. Additionally, literature was reviewed to indicate the effectiveness of policy instruments in promoting renewable energy. Finally, the political influences that may affect renewable energy development or policy formulation were analyzed through a review of literature. The study indicates that renewable energy, particularly biomass, has some potential in Mississippi. Although the political environment may not be conducive to policy innovation, a renewable energy policy from the state level should be the most effective tool in promoting renewable development.
|
37 |
Economics of corn stover as a coal supplement in steam-electric power plants in the north central United States /Abdallah, Mohammed Hamid January 1978 (has links)
No description available.
|
38 |
Renewable energies management strategy challenges in the Arabian Gulf countriesAloughani, Muhammad January 2015 (has links)
The main source of energy in the Gulf Cooperation Council (GCC) remains fossil fuels (oil and gas). The massive and accelerated used of such sources of energy not only depletes the traditional energy sources in those states and thus undermines exports and long-term prosperity; it also causes devastating damages to the environment and to human health. The nature of the Arabian Peninsula is very suitable for renewable energy sources (RES), thus many GCC states have started to consider those resources for their future energy plans. Like any technology, renewable energy technologies (RET) face many challenges such as economic, technical, social and environmental. This research analyses renewable energy (RE) possibilities and barriers in the GCC states in depth, using Kuwait as a case study. Questionnaires were distributed to three different groups to measure their attitudes and knowledge with regard to RE. Moreover, this research investigates the economic and environmental implications of RES adoption for Kuwait. A cost analysis between the traditional energy generated by the Ministry of Electricity and Water (MEW) using oil and gas, and RE energy generated by Al- Shagaya project has been carried out. It was found that most participants were environmentally aware of fuel issues and supported RE; they were prepared to forego subsidies on traditional energy to promote RE, but they doubted the government’s ability to implement RE successfully. Although Al-Shagaya Project was targeted to contribute up to 15% of Kuwait’s total power production by 2030, the cost analysis presented in this thesis revealed that the energy generated from the Al-Shagaya Project accounts for only 2% the energy needs projected at 2030, therefore current plans would only reduce CO2 emissions by 2% by 2030, but a program was proposed whereby larger investment would cause a 92% reduction in costs and reduce CO2 emissions to zero within the same timeframe.
|
39 |
Analysis of bioenergy crops as a production alternative for a representative East Tennessee beef and crop farmGriffith, Andrew Preston, January 2009 (has links) (PDF)
Thesis (M.S.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Oct. 23, 2009). Thesis advisor: James A. Larson. Vita. Includes bibliographical references.
|
40 |
THE FINANCIAL SECTOR AND RENEWABLE ENERGY DEVELOPMENT IN NON-OECD COUNTRIES: AN EMPIRICAL ANALYSISNADEEM, SYED ALI 05 April 2013 (has links)
This paper examines the role of the financial sector in the development of renewable energy generation in non-OECD countries. A panel dataset of 156 countries is constructed from 1980-2006. The estimations suggest a positive impact of commercial banking on non-hydro energy production such as wind, solar and geo-thermal. None of the equity market indicators suggest a positive relationship. There is also strong evidence that the Kyoto Protocol has had a positive impact on renewable energy development
|
Page generated in 0.0825 seconds