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Dissertations / Theses on the topic 'Solar system'
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Sengil, Nevsan. "Solar cell concentrator system." Thesis, Monterey, California: U.S. Naval Postgraduate School, 1986. http://hdl.handle.net/10945/22111.
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Sukki, Firdaus Muhammad. "Optimised solar concentrator for the soar photonic optoelectronic transformer system." Thesis, Glasgow Caledonian University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601455.
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Malaysia is one of the countries that have started to elevate the usage of renewable - specifically solar photovoltaic (PV) - in delivering its energy needs. This thesis is divided into two main sections. The first section evaluates the solar PV installations in the residential sector in Malaysia for the past 20 years; in terms of policies, research and development activities and implementations. Recently, the Feed-in Tariff (FiT) scheme was introduced in Malaysia and based on the financial analysis, any installation of solar PV could generate a lucrative monthly income to the household owner under the FiT scheme. However, a preliminary survey indicated that Malaysians are not interested in investing in a solar PV system, mainly due to the high cost of implementation. The next section focuses on the design of solar concentrators - particularly the family of Dielectric Totally Internally Reflecting Concentrators (DTIRCs) - with the aim of achieving a low cost solar PV system. Part of the PhD project is the optimisation of the concentrator design in the Solar Photonic Optoelectronic Transformer (SPOT), the main component of SolarBrane, a static building integrated PV (BlPV) system developed by SolarEmpower Ltd. An optimised design has been proposed using a DTIRC based on the Maximum Concentration Method (MCM). It has been demonstrated via simulations that the optimised design could potentially increase the output of the SolarBrane, at the cost of having a slightly larger structure. A novel type of DTIRC family. known as the Asymmetrical DTIRC (ADTIRC). has been developed to provide additional gain at the "extrusion" plane of the concentrator, and further reducing the size of the PV cell needed. It is concluded tbat this new design generates a much higher gain compared to the concentrator in the SolarBranel. The results from the indoor experiments indicate that the ADTIRC-PV structure could increase the electrical output by 4.2x when compared with the non-concentrating solar PV cell.
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Yang, Sun. "Solar Energy Control System Design." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141489.
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This thesis covers design, simulation and implementation of a solar energy control system for an on grid energy storage device. The design covers several control methods such as energy balance control, operating mode switching and data exchange. A genetic algorithm was designed to optimize the control system parameters design, and the algorithm's simulation and real time operating system implementation showed comparable results. The control system was implemented to connect a power supply to the grid. The power supply simulated a solar panel and connected to an electrical grid via Energy Hub equipment, and the energy transfer characteristics of designed control system were tested. The results showed that the selected algorithm matches the target performance criteria.
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Shafi, Muhammad Irfan, and Md Maidur Rehman Talukder. "Development of Hybrid Solar System." Thesis, Högskolan i Gävle, Akademin för teknik och miljö, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-13927.
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Technology replaces newer technology with improved efficiency. Solar technology is going to draw out a new life to make a green change in the terms of energy. As a result energy from the sunlight is being changed into electric energy by using solar cell. But still its efficiency could not be able to make a sense as a depending energy technology. In order to look up the solution, solar technology is changing rapidly to get maximum output. To take up this new challenge solar technology is trying to change its building component that are used to make solar cell, for example solar cell material, bypass diode system, blocking diode system etc. Now-a-days, solar energy system is designed as a hybrid system that can make electricity and hot water at the same time. In the hybrid solar system, photovoltaic and solar thermal systems are integrated at the same system and as a result heat and electricity are produced simultaneously at the same area. Solar cells are attached with both top and the bottom side of the module and the collectors are set up inside the module. By using collector inside the module, rejected heat from the solar cell is absorbed by the water that flows through the collectors. But a problem arises at the midday or after midday because the reflector of this system cannot reflect sunlight properly on the bottom side of the module. That’s why shading is occurred on the bottom side which reduce the total electrical output of this system. To work out this shading problem, a bypass diode is connected in parallel with the group of solar cells. Schottky diodes are being used as bypass diodes inside in the most of the solar cells. Schottky diode forward voltage drop is almost 0.45 Volt which is an important cause of reducing the output power as well as the efficiency of this hybrid system. To solve this problem, new lossless diode is attached inside the hybrid solar system instead of schottky diode which can work with a very low forward voltage drop roughly 50mV at 10amp. To make a comparison between the performance of PVT system with the schottky diode and the new lossless diode, many data has been collected from the outdoor test. After getting the output result, it is clear that the output power and efficiency is going to be changed for using the new lossless diode. For using the lossless diode, the efficiency of the bottom side of the module was increased by 0.31 %.
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Al-Madhhachi, Hayder. "Solar powered thermoelectric distillation system." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/107598/.
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An efficient thermoelectric distillation system was designed, constructed and tested. The unique aspect of this design is to use the waste heat from the hot side of thermoelectric module for heating of the feed water, to improve the evaporation while using the cold side of the module to cool the condenser and improve the condensation process. The developed thermoelectric distillation system produces 28.5 mL of distilled water (equivalent to 678 mL/m2) over a period of 1 hour. The corresponding electrical energy required for the water production is 0.0324 kWh, which gives a specific energy consumption of 0.00114 kWh/mL. The developed system in this research has significantly lower energy consumption than the existing thermoelectric distillation systems. The transient to steady state behaviour of the developed thermoelectric distillation system was investigated. It was found that the system reaches steady state after approximately three hours of the system operation. The water temperature in evaporation chamber was increased from 22.3 oC to 47.8 oC. Similarly, the vapour temperature was increased moderately from 20.3 oC to 30.4 oC. The steady state water production, humidity, energy consumption and COP of the thermoelectric distillation system were 15.3 mL/h, 81%, 0.0324 kWh and 1.04, respectively. Thermal models have been developed through water-vapour phase-change theory to interpret the evaporation and condensation processes involved in the fresh water production of the thermoelectric distillation system. The first model was related to the evaporation process to determine the vapour production in the system. A theoretical distillation ratio of 12% was obtained, with a predicted water temperature of 42.7 oC. This is in reasonable agreement with the 9.5% value experimentally obtained. The second ii model has been developed for the water condensation process. The developed model can be used for determining the key parameters that control the condensation processes and the system thermal performance. This model shows that the rate of water condensation is dependent upon the convection heat transfer coefficient of the cold-side heat exchanger. The fitted value of the convection heat transfer coefficient in the thermoelectric distillation system is 8 W/m2.K. Key factors that influence the total water production and water production rate have been investigated, including sample water temperature, vapour volume at sample water level, Peltier current and thermoelectric input power. The experimental data shows that an increase in sample water temperature from 30 oC to 60 oC gives a 47 % increase in total water production. Peltier current is demonstrated as a control factor in the design of an effective thermoelectric distillation system. The results show that the total water production increases by 61%, when the volume occupied by the vapour is reduced from 600 cm3 to 400 cm3 by increasing the sample water level from 10 mm to 30 mm in the system. The maximum water production is achieved by increasing sample water temperature and the corresponding optimised input power. Measurements of the distilled water show that it has similar quality to drinkable tap water in terms of pH, total dissolved solids and electrical conductivity values. Photovoltaic Geographical Information System was used to estimate the global irradiation per square meter and the solar electricity generation in kWh received by a solar panel in a specific region. Using the experimental prototype, the maximum monthly average water production is 4023.3 mL when using 8.52 kWh of electricity produced during March at the University of Kufa. The minimum average monthly water production is 2970.3 mL using 6.29 kWh of electricity produced during November.
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Gibbard, Seran Gwen 1967. "Lightning in the solar system." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/290640.
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Lightning, a familiar phenomenon on Earth, may also occur at other times and locations in our solar system. It has been suggested as a mechanism for forming chondrules, millimeter-sized beads of glassy silicate found in primitive meteorites formed in the early solar system 4.5 billion years ago. It has also been detected in Voyager images of Jupiter, and there is evidence that it may occur on other planets as well, including Venus, Saturn and Neptune. The mechanism believed to produce lightning discharges on Earth, and possibly other planets, is charge production by collisions of ice particles, followed by gravitational separation of oppositely-charged large and small particles. This work examines the possibility of the occurrence of lightning discharges in the atmospheres of Jupiter and Neptune as well as in the protoplanetary nebula (PPN) of the early solar system by modeling charge separation and growth of the electric field. The model is also applied to the Earth as a test of its predictive power. It is found that the model can reproduce the correct timescale, particle charge and electric field magnitude seen in terrestrial lightning. The model also predicts lightning on Jupiter at the 3-5 bar level provided that the local water abundance is greater than the solar value. This is a much higher abundance than measured by the Galileo probe into Jupiter's atmosphere, which suggests that the water content measured by the probe does not apply to the entire planet. An application of the model to Neptune's water and NH₄SH clouds finds that lightning is unlikely in these clouds due to the large electric field required for electrical breakdown. Lightning may be possible in the overlying H₂S-NH₃ cloud provided that these substances can undergo collisional charge exchange with a magnitude at least 1% of that found in water ice. In the protoplanetary nebula, it appears that large-scale precipitation-induced lightning could not have occurred, due to the small mass density, low temperature and high electrical conductivity of the surroundings. This is a robust conclusion that does not depend sensitively on the values of the parameters involved.
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Mkhize, Mfanafuthi Mthandeni. "Multistage solar still desalination system." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2848.
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Thesis (Master of Engineering in Mechanical Engineering)--Cape Peninsula University of Technology, 2018.The present study was centred on the design of a thermal multistage solar still desalination system. The design is a multistage with new configurations such as direct vapour input into each stage using vapour make-up tubes and the integration of a multistage with a basin type solar still. The incorporation of float a valve in the secondary seawater tank to regulate the seawater in the assembly eliminated the need of pumps to the system. The circulation of seawater between the evaporator and the evacuated tube solar collector (ETC) was through the pressure difference and the flow back was controlled through the incorporation of oneway flow valve. The ETC was used as a heat source to supply the thermal energy into the multistage system. The system had no electrical connections and therefore, no forced circulation as no pumps or any electrical components were used. The system consisted of six stages in total, the evaporator supplied the vapour to five of the six stages of the system. The system was tested on the roof of Mechanical Engineering Department and this location was chosen because of less sun’s intensity obstructions. The system was tested for nine (9) days but the distillate collection was not performed for the whole each day. This was due to the controlled access to the roof and the minor repairs that had to occur before the tests were conducted. The duration on which the tests were conducted varied in each day. The data was supposed to be logged from 08h00 am to 18h00 pm but this was not so due to the controlled access to where the tests were conducted. This data logging period was chosen based on the assumptions that the sun’s intensity would be at maximum within this period. The longest period of test was approximately 7 hours and the system managed to produce about 1500 ml and the maximum temperature for the day was 28oC. The system produced a minimum of 225 ml in the space of 3 hours and the temperature of the day was 26oC. The total amount of distillate produced was about 7600 ml and this amount was produced within the period of 49 hours. The 49 hours is equivalent to two days and 1 hour. It is anticipated that the system would have produced more should there be no repairs involved during the tests. The system produced a maximum of 48 ml at night and a minimum of 8ml in some nights. The night tests were not controlled and monitored due to limited access. It was noticed that the system was empty in each morning of the first few days of the tests. This emptiness contributed to the leakage occurred to the evaporator. The leakage of the evaporator was caused by unmonitored heat supplied by the ETC. The evaporator was constructed using unsuitable material and this was another factor which contributed towards the failure of the evaporator.
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Ibrahim, Munzer. "Solar Powered Air Conditioning System." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-39522.
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Dorn, Lawrence Tyrone. "NPS-SCAT electrical power system." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep_Dorn.pdf.
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Thesis (M.S. in Space Systems Operations)--Naval Postgraduate School, September 2009.Thesis Advisor(s): Newman, James H. "September 2009." Description based on title screen as viewed on November 5, 2009. Author(s) subject terms: Satellite, CubeSat, NPS-SCAT, solar cell tester, Power system, Clyde Space, Spectrolabs, improved triple junction, solar power. Includes bibliographical references (p. 83-85). Also available in print.
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Sun, Li. "Implementations of electric vehicle system based on solar energy in Singapore : assessment of solar photovoltaic systems." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54563.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 150-156).
To evaluate the feasibility of solar energy based Electric Vehicle Transportation System in Singapore, the state of the art Photovoltaic Systems have been reviewed in this report with a focus on solar cell technologies. Various solar cell technologies were evaluated based on characteristics such as efficiency, reliability and cost to identify a best working one under Singapore's hot and humid climate. Commercial CdTe modules were found to have the best efficiency to cost ratio, making them the best module choice in land-scarce and tropical Singapore. Based on the market price and characteristics of CdTe modules from manufacturer First Solar Ltd, two PV systems based on an apartment model and a private house model were evaluated. The cost of electricity from a relatively large scale grid-tied PV system is found to be at around US$0.173/kWh which is not market competitive with the utility electricity price of US$0.109/kWh in Singapore. But with enough capital funding and government incentives such as rebate or feed-in price tariff, PV electricity generation could become economically feasible. The small private house system is found not economical as a means of household electricity generation even with current status of government rebate. When carbon trading is considered, the current trading price has to be increased by around 7 times of the current value or 3 times of the predicted price at 2016 to offset the difference with the utility electricity price.
by Li Sun.
M.Eng.
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Foley, Brian S. B. (Brian M. ). Massachusetts Institute of Technology. "Solar thermal collector system modeling and testing for novel solar cooker." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92179.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (page 22).
Solar cookers are aimed at reducing pollution and desertification in the developing world. However, they are often disregarded as they do not give users the ability to cook after daylight hours. The Wilson solar cooker is a solar cooker designed to address this problem by converting solar energy and storing that energy as heat in the form of molten salt (lithium nitrate). This thesis involved research, modeling, and experimentation for the solar collection system of the cooker. This thesis looked at prior research on glazing, Fresnel lenses, and absorber surface treatments to identify and evaluate elements for use in the collection system. Borosilicate glass, with a thermal conductivity of 1.005 W/mK and a solar transmittance of 0.91, and flat black paint, with absorptivity 0.96 and emissivity 0.88 were identified as potential elements for use in first trials. Experimentation was performed on copper and aluminum samples with various surface treatments powered by various Fresnel lenses to evaluate the relative efficiency of these treatments. A novel treatment method, machining a conical hole into the sample, was found to improve efficiency on untreated samples, but inferior to flat black paint. Modeling predicted that the minimum collection area for an acrylic Fresnel lens off-number 1.2 was 0.60 m² for and 0.65 m² for the proposed collector without and with glazing, respectively. A recommendation of collection area 1 m² was proposed to account for unexpected losses due to manufacturing errors, positioning errors, and environmental variation. This thesis also analyzed a proposal for a novel solar collector, a polished aluminum cone. Modeling and efficiency testing showed the cone to be inadequate for the radiation collection needed for the solar cooker.
by Brian Foley.
S.B.
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Thomas, Alex S. M. Massachusetts Institute of Technology. "An analysis of distributed solar fuel systems." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76511.
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Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 85-89).
While solar fuel systems offer tremendous potential to address global clean energy needs, most existing analyses have focused on the feasibility of large centralized systems and applications. Not much research exists on the feasibility of distributed solar fuel systems. This thesis is an attempt to understand the larger context of solar fuel systems, to examine the case for going distributed and to critically analyze a distributed solar fuel system available today in the context of a specific application. In doing so, this thesis seeks to a) provide a baseline analysis for the economic feasibility of a distributed solar fuel system based on state-of-the-art technology b) draw some general conclusions about the nature of such systems in order to provide guidance to those engaged in the development of the next generation of solar fuel systems. This study also compares the chosen baseline solar fuel system with a traditional fossil fuel-based alternative and undertakes a cost-to-emissions trade-off analysis. A key finding of this thesis is that for solar fuel systems to be viable, cost and efficiency improvements in individual sub-systems won't be sufficient. Due attention needs to be given to bring down cost of the entire system. Another key finding is that if carbon emissions are considered as a decision-making criterion in addition to cost, even at current cost levels photovoltaic hydrogen systems compare favorably with existing fossil fuel-based alternatives such as diesel generators.
by Alex Thomas.
S.M.in Engineering and Management
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Ghaghazanian, Arash. "System Integration of PV/T Collectors in Solar Cooling Systems." Thesis, Högskolan Dalarna, Energiteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:du-19554.
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The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high. This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices. The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume. The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.
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Kristofersson, Filip, and Sara Elfberg. "Maximizing Solar Energy Production for Västra Stenhagenskolan : Designing an Optimal PV System." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-384723.
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Skolfastigheter is a municipality owned real estate company that manages most of the buildings used for lower education in Uppsala. The company is working in line with the environmental goals of the municipality by installing photovoltaic systems in schools and other educational buildings. Skolfastigheter are planning to install a photovoltaic system in a school in Stenhagen. The purpose of this study is to optimally design the proposed system. The system will be maximized, which in this study entails that the modules will be placed on every part of the roof where the insolation is sufficient. The system will also be grid connected. The design process includes finding an optimal placement of the modules, matching them with a suitable inverter bank and evaluating the potential of a battery storage. Economic aspects such as taxes, subsidies and electricity prices are taken into account when the system is simulated and analyzed. A sensitivity analysis is carried out to evaluate how the capacity of a battery bank affects the self-consumption, self-sufficiency and cost of the system. It is concluded that the optimal system has a total peak power of almost 600 kW and a net present value of 826 TSEK, meaning that it would be a profitable investment. A battery bank is excluded from the optimal design, since increasing the capacity of the bank steadily decreased the net present value and only marginally increased the self-consumption and self-sufficiency of the system.
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Magnusson, Erik, and Johan Schedwin. "Development of solar water heating system." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-4428.
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This report includes development of an already designed solar water heater. The product shall be constructed in a way that it will suit a manufacturing line in Kampala, Uganda. To find the most suitable design for each area a research was carried out which included study visits, interviews and background reading. It provided the following results: Regarding the attachment of in- and outgoing pipes from the water tank many methods were taken into consideration and it was found that the best and most suitable way for this case is to weld the fittings using a weld robot. Regarding the fitting of the acrylic, a suitable solution is to make a flange when vacuum forming the plastic casing to further support the design. This could also be used to waterproof the case by using a sealing material. A suggestion of using pre-molded PU-foam is also presented. Regarding the ability to open the case for maintenance, two solutions were recommended. Either the use of spire clips or having the clips integrated into the casing. Regarding the calculation of material usage when deep drawing the tank and collector, it is possible to do a reasonably accurate assumption. The complicated design in this product makes the estimation less accurate. It is recommended that test draws are done and often the machine producer has more precise numbers. Regarding the coloring of the collector; chemical coloration is not possible on a galvanized surface. The method used is painting, either with powder coating or with wet paint.
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Franklin, Edward A. "Mounting Your Solar Photovoltaic (PV) System." College of Agriculture, University of Arizona (Tucson, AZ), 2017. http://hdl.handle.net/10150/625443.
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Flynn, Angela Elizabeth. "Rotational dynamics in the solar system." Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420310.
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Arden, John Walter. "Lead in the early solar system." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257664.
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Busch, Brian C. "Space-based solar power system architecture." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/27802.
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Fossil fuels are, by their very nature, finite resources. There are, however, numerous renewable energy sources that should be taken advantage of. One of the most abundant is also the most difficult to produce on Earthsolar energy. This thesis explores the feasibility of a space-based solar power satellite. The thesis focuses specifically on the satellite design as opposed to the end-to-end design to include the ground segment. It explores the potential orbits for such a satellite to operate from and ultimately concludes that a geostationary orbit is the only logical location for an operational orbit. This thesis also focuses on two segments of the spacecraft the solar array and the power transmission payload. The solar array area was calculated using the current best theoretical solar cells and assumed a 1 GW transmission power. Finally, this thesis explored which transmission payload to recommend for an operational system, concluding that a laser system is the most efficient use of space and weight. The final portion of this thesis was to examine the business case. Based on the design in this thesis, space-based solar power cannot compete with fossil fuels and likely will not for the foreseeable future.
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Court, Richard W. "Organic polymerisation in the solar system." Thesis, Open University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427735.
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Crida, Aurélien. "Planetary migration in solar system formation." Nice, 2006. http://www.theses.fr/2006NICE4076.
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Planetary migration seems to be unavoidable during planet formation in protoplanetary disks. Gravitational interactions between the planet embryos and the gas disk make the angular momentum of the embryo decrease, so that it spirals towards the central star. As the migration timescale is shorter than the disk life time, no planet should survive (chapters 1 and 2). In this thesis, we try to find mechanisms that prevent or slow down migration. In chapter 3, we show that a jump in the gas disk density stops migration and acts like a planet trap. Trapped there, a massif solid core may accrete a gaseous atmosphere and give birth to a giant planet. The planet is then massive enough to repel the gas and open a gap around its orbit. Through analysis of computer simulations, we enlighten the role of pressure effects in this process in chapter 4 ; a new generalized gap opening criterion is derived. After the presentation of a new, reliable and performing algorithm for numerical simulations in chapter 5, we use it in chapter 6 to study the migration of a giant planet and its influence on the disk evolution. The formation of a cavity appears to be less easy than previously expected, but we find a way of preventing migration. Last, in chapter 7, we focus on the case of Jupiter and Saturn, and we find in which conditions the interactions between both planets prevent their migrationLa migration planétaire est un phénomène apparemment inévitable lors de la formation des planètes dans les disques protoplanétaires. Les interactions gravitationnelles entre les embryons de planète et le disque de gaz font décroître le moment cinétique de l'embryon, qui spirale vers l'étoile centrale. Le temps de migration étant plus court que la durée de vie du disque, aucune planète ne devrait survivre (chapitres 1 et 2). Dans cette thèse, nous essayons de trouver des mécanismes qui empêchent ou ralentissent la migration. Dans le chapitre 3, nous montrons qu'un saut dans le profil de densité du disque de gaz bloque la migration et agit comme un piège à planète. Ainsi bloqué, un coeur solide massif peut accrèter une atmosphère gazeuse et devenir une planète géante. La planète est alors assez massive pour repousser le gaz et ouvrir un sillon autour de son orbite. En analysant des simulations numériques, nous mettons en évidence le rôle des effets de pression dans ce processus dans le chapitre 4; un nouveau critère unifié d'ouverture du sillon en découle. Après la présentation dans le chapitre 5 d'un nouvel algorithme fiable et performant pour réaliser des simulations numériques, nous l'utilisons dans le chapitre 6 pour étudier la migration d'une planète géante et son impact sur l'évolution du disque. La formation d'une cavité s'avère moins facile que prévu, mais une possibilité d'arrêter la migration apparaît. Enfin, dans le chapitre 7, nous étudions le cas de Jupiter et Saturne, et trouvons dans quelles conditions les interactions entre les deux planètes en empêchent la migration
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Kargel, Jeffrey Stuart. "Cryomagmatism in the outer solar system." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185177.
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Cryovolcanism has played an important role in the geological histories of many icy satellites. Cryovolcanism, like the more familiar silicate volcanism on Earth and the other terrestrial planets, takes many forms. Many individual cryovolcanic landforms are morphologically surprisingly similar to terrestrial volcanic landforms and can be explained with similar mechanisms. However, assemblages of cryovolcanic, tectonic, and impact structures form unique and varied landscapes quite alien in their collective expression. Many variables can affect the cryovolcanic style of a satellite but none more so than cryolava composition. This work considers the compositional variable in considerable detail. This work summarises existing knowledge of phase equilibria and physical properties of cosmochemically relevant unary, binary, and multi-component chemical systems, and where published knowledge was found lacking, the author presents his own measurements of the physical chemistry of volatile mixtures. The author then takes the reader on a brief tour of cryovolcanic landscapes, and applies knowledge of the physical chemistry of volatile mixtures to problems of cryovolcanological interest. Aqueous cryolavas may range in composition from salt-water brines to cryogenic ammonia-water-rich multi-component solutions possibly involving methanol, ammonium sulfide, alkali chlorides, and many other potential components. Cryomagmatic distillation can greatly accentuate the importance of trace and minor constituents of icy satellites. The viscosities, densities, and other physical properties of these liquids vary considerably and depend sensitively on their exact compositions. These properties affect everything from cryovolcanic eruptive styles and landforms, to the way cryovolcanic crusts respond to tectonic stresses. It is believed that the compositional variable is directly or indirectly implicated in a wide variety of geomorphic aspects of contrast among the icy satellites. Thus, even though we can not as yet confidently attribute any specific morphology to a specific composition (for lack of in situ compositional analyses), there appears to be a powerful link between the composition of the ices originally accreted by a satellite and its subsequent interior evolution and exterior geomorphic appearance.
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Elhabishi, Ali Mohamed. "Optimising collector plate geometry for a specific solar syphon system design." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2385.
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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.
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Celik, Ali Naci. "The system performance and sizing of autonomous pholtovoltaic, wind and the hybrid energy systems." Thesis, Cardiff University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275214.
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Bader, Tobias. "Solar desiccant evaporative cooling with multivalent use of solar thermal heat." Thesis, De Montfort University, 2014. http://hdl.handle.net/2086/10891.
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Solar DEC (Desiccant and Evaporative Cooling) air-conditioning is a renewable technological approach to the future air-conditioning of buildings driven with solar-thermal heat. The principal acceptance of solar airconditioning has led to system prototypes mainly across Europe, however the diffusion of this innovative technology is proceeding slowly due to little field testing experience. In climates with coexisting heating demand particularly, a multivalent system approach that utilizes solar-heat not only for air-conditioning but also for hot water preparation and heating has potential as a feasible concept. However, previous research focused on systems using solar heat exclusively for the DEC-process. This research contributes to the advancement of the solar DEC-technology with multivalent use of solar thermal heat. The investigation consists of an initial detailed in-situ monitoring analysis of a system prototype operated in an industrial environment, followed by the development of optimised system concepts and a climate-specific analysis of the solar DEC-technology. The monitoring provided in-depth knowledge about the system operation, revealing the reasons for the insufficient refrigeration capacity achieved in practice. A detailed simulation model for an entire multivalent solar DEC-system including the heat sinks, DEC-system, heating and hot-water preparation was developed and a DEC-control strategy has been formulated. A new optimised control strategy for multivalent systems with simultaneous sink supply concept was devised. A sensitivity analysis was carried out to investigate the key design parameters for the dimensioning of multivalent solar DEC-systems. The research concluded that the auxiliary primary energy consumption of the optimised system was lower by one third compared to the initial system. Finally, a methodological zoning approach was developed, to systematically produce design-specific outline data for the application of the solar DEC-technology at climatically different sites.
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Akram, Waheed. "Zirconium isotope heterogeneities in the solar system." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/zirconium-isotope-heterogeneities-in-the-solar-system(0bc316ef-6e93-4609-a17b-f3c2255bad61).html.
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Laboratory measurements of primitive and differentiated meteorites have been made in order to understand the origin of isotopic anomalies. The element Zr is chosen for analysis, due to its potential for nuclear and astrophysical applications. Zirconium has five stable isotopes that are produced in different (neutron–capture) nucleosynthetic processes. By analysing the Zr isotope composition of meteorites, we are able to track the mixing of various neutron capture processes in the early Solar System. Measurements have been performed on carbonaceous, ordinary and enstatite chondrites, eucrites, the Moon and Earth. Samples are crushed, digested and passed through a two stage anion exchange separation to obtain a clean Zr fraction. All Zr measurements are made on a Nu Plasma multiple–collector inductively coupled plasma mass spectrometer (MC–ICPMS). The results indicate that the bulk of refractory Ca–Al rich inclusions of the Allende meteorite are characterised by uniform enrichments (around 2ε) of the neutron–rich isotope 96Zr, and potentially coupled with excesses reported for the neutron rich isotope 50Ti, indicating that both nuclides may have similar astrophysical origins. Analysis of bulk rock carbonaceous chondrites reveal 96Zr excesses (not exceeding 1ε) that scale with the abundance of CAIs. However, widespread 96Zr correlations are also seen, accompanied by minor depletions in 91Zr, which suggest the solar nebular had experienced thermal heating of some sort, altering the initial (possibly uniform) Zr isotope composition of the early Solar System from which planetary bodies formed.
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Tefera, Misrak A. "Electricity Production from Concentrated Solar Power and PV System in Ethiopia." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40426.
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Ethiopia has been facing problems regarding power generation, distribution, balancingbetween demand and supply and access to modern energy service. About 92.4% of energysupply is from biomass (mostly in traditional) 5.7% oil which is not friendly with theenvironment and about 1.6% of energy supply is from renewable energy resource,hydropower plants.Being dependent on hydropower plant causes the country to face many challenges indistribution and balancing demand and supply. This thesis provides another way ofconsidering and implementing renewable energy resource (solar energy resource) throughtechnologies like grid-connected roof mounted solar PV system and CSP plant with the helpof PVGIS, PVWatt and SAM software.This thesis aims to come up with an idea that will work out for current engineering, socialand political issue that is seen in the country. Considering new way in planting PV system onthe roof is strongly recommended and increasing the alternative sites for power generationalong with the appropriate technology is recommended as another way. The possibility andpower generating efficiency is checked through each application.Based on the demonstration in all software’s used, it is clearly visible that the country couldhave been satisfied the needed demand and become the hub of east Africa as mentioned inthe policy and strategy. However, this dependency causes the country to insufficiently supplythe need. Apart from the possibilities and estimation, ideas that might help the country tocome over these challenges are provided in recommendation section.
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Lachin, Anoosh. "Low frequency waves in the solar system." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267713.
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Savopulos, Mihail. "Diffusive shock acceleration in the solar system." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338433.
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Soja, Rachel Halina. "Dynamics of the Solar System Meteoroid Population." Thesis, University of Canterbury. Department of Physics and Astronomy, 2010. http://hdl.handle.net/10092/4305.
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The purpose of this study is to develop an understanding of the observability of small-scale dynamical Solar System features in meteor orbit radar data, particularly with reference to mean motion resonance effects. Particular focus is placed on the presence of `resonant swarms' in meteoroid streams: the resonant swarm at the 7:2 Jovian mean-motion resonance is used as an example, as it best satisfies radar observability criterion. Furthermore, evidence for this structure exists in visual meteor data. The radar dataset used for this study is that of the Canadian Meteor Orbit Radar (CMOR) as this dataset contains the largest number of meteoroid stream particles. The aim here is to determine whether the Taurid resonant swarm is observable in datasets produced by radars such as CMOR, or what improvements in individual orbital uncertainties are necessary for positive detection to be possible.
The observability of the Taurid swarm in radar data depends on the limitations of the radar data (in terms of the individual measurement uncertainties); and on the properties of the resonance itself. Both aspects are investigated in this thesis. A statistical study is first conducted to assess whether evidence for the swarm exists in a dataset containing CMOR Northern and Southern Taurids from the years 2002 to 2007. It is found that the level of variations present is consistent with that expected due to random fluctuations: there is no evidence for a statistically significant resonant feature at the location of the 7:2 Jovian resonance. Additionally, the observability of various sizes of resonant peak for different sizes of dataset and for different levels of measurement uncertainties is investigated by addition of a modelled resonant feature to the data, followed by replacement of individual meteors by Gaussian profiles to simulate the effect of orbital uncertainties. It is clear that the level of broadening resulting from the uncertainties of the CMOR data used will not allow the observation of a resonant peak of the expected size. Detection is expected to be more likely in a `swarm encounter year' (a year in which the geometry between the resonant swarm and Earth is favourable to detection). The velocity uncertainties of a meteor orbit radar (similar to CMOR) need to be improved by a factor of 5 to 10 (relative to the CMOR uncertainties) in order to detect a resonant swarm that is composed of ~30% to ~5% (respectively) of the total number of observed Taurids in a swarm encounter year. An improvement significantly greater than a factor of ~10 is unlikely to result in a significant improvement in the ability to detect the resonant swarm. It is expected that a factor of 10 improvement in radar measurement uncertainties is achievable with the current techniques of radar systems and signal processing.
These statistical tests require knowledge of the resonant width of the 7:2 Jovian resonance in semi-major axis, as this provides the size of the resonant feature of interest. Such resonant or libration widths can be determined analytically for orbits with low eccentricities. As Taurid orbits have high eccentricities (e~0.83), a hierarchical N-body integrator is used to examine the dynamics in the region of the 7:2 resonance, and determine a resonant width of (0.047±0.005) AU. To verify this method the standard analytic equations and a semi-analytic method are compared (at low eccentricities) with the numerical resonant width values: the agreement is within 10% for eccentricities below 0.4.
It is important to know what proportion of radar Taurids are expected to be resonant in a swarm year in order to evaluate the observability of the swarm in radar data. One important factor that may affect this is the mass distribution of particles in the swarm. This is investigated by ejecting particles in multiple directions from three model comets: the first with a mass and orbit in agreement with those of the current 2P/Encke; the second with 2P/Encke mass and an orbit matching that of the proposed proto-Encke object; and a third with the mass and orbit of proto-Encke. The resulting orbits are examined to determine what proportion will land within the 7:2 resonance, for a range of particle masses and densities. The instantaneous effect of radiation pressure on the orbits of ejected particles is also considered. However, it is difficult to determine accurate capture percentage values due to the uncertainty surrounding cometary ejection mechanisms. Nevertheless, it is found that capture of Taurids into the 7:2 resonance by all comets is possible. Using comparisons between the percentages of visual-sized and radar-sized particles captured, it is determined that in weak swarm years (in which only 20% of visual meteoroids detected are resonant) only 4% to 5% of observed visual Taurids are expected to be resonant. Such a swarm would be on the edge of observability. However, in stronger swarm years (such as 2005), the resonant proportion will exceed that required for detection with a reduction in CMOR measurement uncertainties of a factor of ten.
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Fu, Roger R. (Roger Rennan). "Magnetic fields in the early solar system." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101348.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 251-283).
The first magnetic fields in the solar system were embedded in the ionized gas of the protoplanetary disk itself. Soon after, newly formed protoplanets may have harbored magnetic core dynamos. Paleomagnetic analysis of ancient samples permits direct constraints on these early solar system magnetic fields. Here I present paleomagnetic studies of several classes of meteorites. Experiments on inclusions of chondritic meteorites have led to some of the first constraints on the intensities of protoplanetary disk magnetic fields. Meanwhile, measurements of eucrites, a class of achondrites believed to originate from the asteroid Vesta, suggest that Vesta once hosted a magnetic core dynamo. New techniques developed during the course of these measurements permit ongoing and future investigations of the remanent magnetizations of new meteorites and terrestrial rocks. In support of the paleomagnetic results, I present analytical and numerical modeling of magnetic dust grain dynamics in the solar nebula and of the interior dynamics of differentiated asteroids capable of hosting magnetic dynamos.
by Roger R. Fu.
Ph. D.
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Singletary, Steven J. (Steven James) 1973. "Igneous processes of the early solar system." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/58444.
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Thesis (Ph. D. in Geochemistry)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, February 2004.Includes bibliographical references.
Experimental, petrographic and numerical methods are used to explore the igneous evolution of the early solar system. Chapters 1 and 2 detail the results of petrographic and experimental studies of a suite of primitive achondritic meteorites, the ureilites. The first chapter presents data that reveal correlations between mineral modal proportions and mineral chemistry that are used to guide experiments and models of ureilite petrogenesis. Chapter 2 details and applies the experimental results to describe ureilite petrogenesis as the result of progressive heating of a primitive carbon-rich body. The experiments place temperature and depth constraints on uteilite formation of 1100 to 13000C and 5 to 13 MPa - equivalent to the central pressure of an asteroid with a radius of 130 km. Chapter 3 reports the results of melting experiments of Allende carbonaceous chondrite at temperatures and pressures that would be expected on small bodies in the early solar system (up to 1300⁰C and 2.5 to 15 IPa) heated by decay of short lived isotopes. The results are then applied to ureilite petrogenesis and assembly of larger planetary bodies. The final chapter is an experimental study to test a hybridized source region for the high titanium lunar ultramafic glasses. Two models are presented that invoke either a heterogeneous source region or sinking and reaction of an ultramafic, titanium rich magma with underlying mantle regions.
by Steven J. Singletary.
Ph.D.in Geochemistry
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Walter, Eric, Nicholas Glover, Jesse Cureton, and Kurt Kosbar. "Telemetry System Architecture for a Solar Car." International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596465.
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ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NVThis paper discusses the telemetry system used to monitor the performance of a solar-powered vehicle during testing and competitions. Car-side systems collect and transmit data onboard over an ISO 11898 / CAN bus. A bridge then converts this data into TCP/IP packets, which are transmitted via Ethernet to a Wi-Fi access point. The data is distributed through an IEEE 802.11N 5GHz mesh network to provide real time data to remote computers running telemetry software. This software displays and logs data from the car, allowing team members to monitor the vehicle.
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Guenther, Clinton, Robert Mertens, and Adam Lewis. "Telemetry System for the Solar Miner VII." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605981.
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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, CaliforniaThis paper describes a telemetry system used in the Missouri S&T solar car, which competed in the American Solar Challenge. The system monitors parameters of a number of the on-board electronic and mechanical systems, and also the activities of the vehicle driver. This data is transmitted to a lead vehicle, where the support team analyzes the performance in real-time to optimize the vehicle's performance. In previous vehicles the data was displayed using a LabVIEW based user interface. In this work we will describe a custom software solution, which provides the team with additional flexibility to display and analyze the data.
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Marsh, Jasmina Pozderac. "Spin-orbit coupling in the solar system." Thesis, [Austin, Tex. : University of Texas, 2009. http://hdl.handle.net/2152/ETD-UT-2009-05-102.
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Almouayad, Alazm Zafer. "Study on solar driven office cooling system." Thesis, Högskolan i Halmstad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40442.
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Boström, Tobias. "Solution-Chemically Derived Spectrally Selective Solar Absorbers : With System Perspectives on Solar Heating." Doctoral thesis, Uppsala University, Department of Engineering Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7160.
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This thesis consists of two parts, one dominating part concerning spectrally selective solar absorbers and one dealing with thermal solar systems. The appended papers I to VIII concern the solar absorber part, papers dealing with the systems part have not been included in the thesis.
A new spectrally selective absorber derived from a novel solution-chemistry method has been developed and optimized. The main objective was to investigate the potential of the spectrally selective surface. Some of the questions at issue were; would it be possible to create a suitable absorber composite using this method, how high selectivity could be obtained, could the performance be enhanced by using anti-reflection coatings, which was the optimal layer composition, would the thin films be durable and what was the structure and morphology like on a nano scale? The absorber consists of absorbing thin films of nickel nano-particles embedded in a dielectric matrix of alumina and an overlying anti-reflection film consisting of one of the following materials silica, hybrid-silica, alumina or silica-titania. Solution and sol-gel chemistry were used in the process. The thin films were spin-coated onto an aluminum substrate followed by a heat-treatment that generated the multi layer selective solar absorber.
The optical constants for the thin film materials in question were determined. An optimal three layer structure was modeled using the experimentally determined optical constants. The theoretical three layer stack was experimentally confirmed and achieved a solar absorptance of 0.97 and a thermal emittance of 0.05 which definitely are commercially competitive values. The configuration of the three layer stack is: an 80%nickel-20%alumina film at the base, a 40%nickel-60%alumina film in the middle and a silica or hybrid-silica film at the top. The three layer absorber was subjected to high temperature and condensation accelerated ageing tests designed by IEA Task 27. The condensation test did not degrade the absorber whatsoever but the high temperature test did reveal some oxidation of the nickel particles. The oxidation occurs initially and then stops. A formed nickel-oxide layer hinders further oxidation. The level of oxidation is small and the absorber is qualified according to the IEA Task 27 test procedure.
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Boström, Tobias. "Solution-chemically derived spectrally selective solar absorbers : with system perspectives on solar heating /." Uppsala : Acta Universitatis Upsaliensis, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7160.
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Sheu, Elysia J. (Elysia Ja-Zeng). "A solar reforming system for use in hybrid solar-fossil fuel power generation." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103734.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 229-241).
As demand for energy continues to rise, the concern over the increase in emissions grows, prompting much interest in using renewable energy resources such as solar energy. However, there are numerous issues with using solar energy including intermittency and the need for storage. A potential solution is the concept of hybrid solar-fossil fuel power generation. Previous work has shown that utilizing solar reforming in conventional power cycles has higher performance compared to other integration methods. In this thesis, a two level analysis of a hybrid redox redox cycle is performed. First, a system analysis of a hybrid cycle utilizing steam redox reforming is presented. Important cycle design and operation parameters such as the oxidation temperature and reformer operating pressure are identified and their effect on both the reformer and cycle performance is discussed. Simulation results show that increasing oxidation temperature can improve reformer and cycle efficiency. Also shown is that increasing the amount of reforming water leads to a higher reformer efficiency, but can be detrimental to cycle efficiency depending on how the reforming water is utilized. Next, a system analysis for a CO2 redox reforming hybrid cycle and comparison of cycle and reformer performance between a CO 2 redox reformer and steam redox reformer hybrid cycle are presented. Similar to the steam redox system, results show that increasing the oxidation temperature or the amount of reforming CO2 leads to higher reformer and cycle efficiencies. In addition, the comparison between the CO2 and steam redox reformer hybrid cycles shows that the CO2 cycle has the potential to have better overall performance.Based on the system analysis, a reformer level analysis is also performed. A novel receiver reactor concept for a solar steam redox reformer is presented, and a computational model is developed to assess its performance. The receiver-reactor consists of a dumbbell shape absorber system that has two distinct absorbers. This absorber system setup allows for the switching between reduction and oxidation steps without having to constantly change inlet streams to the reactor and is designed such that the inlet connections do not interfere with the solar window. In addition, at any point in time only one solar absorber is irradiated by the solar energy (during the reduction step). Simulation results show that the receiver-reactor strongly absorbs the solar radiation and most of the radiative heat transfer occurs in the front half of the reactor. Moreover, results show that higher conductivity absorber materials are more suitable for long term reactor operation. A sensitivity analysis is also performed for the solar steam redox reformer with respect to different performance metrics. Important parameters include channel size, inlet temperature, and reformer pressure. Moreover, a strategy for reactor design based on performance as well as integration with the power cycle is discussed.
by Elysia J. Sheu.
Ph. D.
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Cyr, Kimberly Ellen 1964. "The distribution of water in the solar nebula: Implications for solar system formation." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/288870.
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Water is important in the solar nebula both because it is extremely abundant and because it condenses out at 5 AU, allowing all three phases of H₂O to play a role in the composition and evolution of the solar system. In this work, a thorough examination of the inward radial drift of ice particles from 5 AU is undertaken. Drift model results are then linked to the outward diffusion of vapor, in one overall model which is numerically evolved over the lifetime of the nebula. Results of the model indicate that while the inner nebula is generally depleted in water vapor, there is a zone in which the vapor is enhanced by ∼40-100%, depending on the choice of ice grain growth mechanisms and rates. This enhancement peaks in the region from 0.1-2 AU and gradually drops off out to 5 AU. Conversely, ice abundance is enhanced over 3-5 AU. Representative hot (early) and cool (later) conditions during the quiescent phase of nebular evolution are examined. Additionally, the effect of the radial dependence of water depletion on nebular chemistry is quantified using a chemical equilibrium code that computes abundances of nebular elements and major molecular C, N, S, etc. species over a range of temperatures. In particular, changes in the local C/O ratio and organics abundance due to the radially dependent decrease in oxygen fugacity are tracked and plotted. Generally, the diffusion-drift model results in a more complex water distribution than previous models, with both radial and temporal variations in the C/O ratio which produce both relatively oxidizing and reducing nebular conditions across 1-5 AU. Depending on the value assumed for the solar C/O ratio, modest to significant enhancements of CH₄ and other organics abundances are produced in the inner nebula. These results coupled with the revised ice distribution may explain the radial signatures of hydration detections and darkening in asteroids, and perhaps the oxidation states of enstatite chondrites. The results also indicate that the inner nebula could have supplied organics and water to the terrestrial planets, as well as possibly to Europa and beyond, via outward mixing processes.
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Ruan, Wenbo. "Energy survey on replacing a direct electrical heating system with an alternative heating system." Thesis, Högskolan i Gävle, Energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-26915.
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With the ever-growing energy demand that world is currently going through and the danger of climate change around the corner, wagering in renewable energy seems to be the right path to create a more smart and green future. Sweden has put great effort on decreasing its dependency on oil, in fact in 2012 more than 50 % of its electricity came from the renewable source and has a plan in making it 100 % in 2040. However, when it comes to heating systems Sweden depends greatly on district heating, and situations which buildings are located outside the district heating system’s reach is not uncommon, hence for those buildings, other options such as solar power or heat pumps are considered. Many buildings located in Skutskär suffer from the problem stated above. The particular building analyzed in this thesis uses electrical radiator and furnace as sources of heat, which implies high energy uses and financial expenses. For this reason technical and financial analysis of using each alternative system for a single family house located in Skutskär had been done. Using solar powered system is deemed to be quite ineffective, as Sweden has poor solar radiation. In order to compensate the poor sun hours during the winter, 51 photovoltaic (PV) panels or 19 solar thermal panels would be required. This high initial investment needs long period of time in order to be profitable, 15 years for solar thermal system and 21 years for solar PV system. On the other hand, the results from the heat pumps are quite satisfactory, the fastest payback period is around 4 years. This is achieved by using air source heat pump (ASHP), the annual saving in this case is three times higher than using solar photovoltaic panels, making the usage of ASHP more attractive than any solar energy system. However, when annual saving is concerned, the ground source heat pump (GSHP) system is capable of generating even higher saving, but the initial investment is significantly higher, extending the payback period to 6 years.
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Poppi, Stefano. "Solar heat pump systems for heating applications : Analysis of system performance and possible solutions for improving system performance." Doctoral thesis, KTH, Energiteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214552.
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Solar heat pump systems (SHPs) are systems that combine solar energy and heat pumps. SHPs have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many solar thermal heat pump systems have become market-available in recent years; however these systems are still not widely employed in the residential sector. This is due mainly to the high initial costs (investment and installation costs) of solar thermal heat pump systems, which limits their cost-effectiveness. Enhancing cost-effectiveness of solar thermal heat pump systems is necessary for a more effective and broader market penetration. In this thesis, solar thermal and photovoltaic systems combined with heat pumps for heating applications are treated. The overall aims of the thesis are to: 1) investigate techno-economics of SHPs and 2) investigate possible solutions for improving system performance of a reference solar thermal and heat pump system for residential heating applications. In the first part of the thesis, the influence of climatic boundary conditions on economic performance of SHPs has been investigated by means of: a) an economic comparison of SHPs found in the relevant literature and b) system simulations of the reference solar thermal heat pump system. In the second part of the thesis, potential solutions for improving system performance of the reference solar thermal heat pump system with limited change in system’ costs are investigated. A systematic approach was used for investigating cost-effectiveness of the system improvements in the reference system. Based on results of the cost-effectiveness analysis, some of the investigated system improvements were chosen for being included in the design of a novel solar thermal and air source heat pump system concept. The novel system was designed for a house standard with relatively high operating temperatures (55°C/45°C) in the space heating distribution system and for high space heating demand (123 kWh/m2·year). Finally, the thesis ends with a cost-effectiveness analysis of the novel system.QC 20170918
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Ma, Jiya. "A Genetic Algorithm for Solar Boat." Thesis, Högskolan Dalarna, Datateknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:du-3488.
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Genetic algorithm has been widely used in different areas of optimization problems. Ithas been combined with renewable energy domain, photovoltaic system, in this thesis.To participate and win the solar boat race, a control program is needed and C++ hasbeen chosen for programming. To implement the program, the mathematic model hasbeen built. Besides, the approaches to calculate the boundaries related to conditionhave been explained. Afterward, the processing of the prediction and real time controlfunction are offered. The program has been simulated and the results proved thatgenetic algorithm is helpful to get the good results but it does not improve the resultstoo much since the particularity of the solar driven boat project such as the limitationof energy production
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Gaynullin, Bakhram. "Universal Experimental Measurement System «Sun-Walker» : Automotive measurement system for the evaluation of the solar irradiation distribution for the tests of the solar concentrated systems." Thesis, Högskolan Dalarna, Energi och miljöteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:du-4925.
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This Thesis project is a part of the research conducted in Solar industry. ABSOLICON Solar Concentrator AB has invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate distribution of density of solar radiation in the focal line of the concentrated parabolic reflectors and to measure radiation from the artificial source of light being a calibration-testing tool.On the basis of the requirements of the company’s administration and needs of designing the concentrated reflectors the operation conditions for the Sun-Walker were formulated. As the first step, the complex design of the whole system was made and division on the parts was specified. After the preliminary conducted simulation of the functions and operation conditions of the all parts were formulated.As the next steps, the detailed design of all the parts was made. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Sun-Walker were assembled and tested. The software part, which controls the Sun-Walker work and conducts measurements of solar irradiation, was created on the LabVIEW basis. To tune and test the software part, the special simulator was designed and assembled.When all parts were assembled in the complete system, the Sun-Walker was tested, calibrated and tuned.
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LIU, Wei-Hung, and 劉威宏. "Remote monitoring system of solar power systems." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/99951128563294019863.
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Chih-Te, Cheng, and 鄭志得. "Solar Energy Conversion System." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/26387511884475669934.
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碩士國立臺灣大學
電機工程學研究所
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The thesis describes the implementation of the Solar Energy Conversion System. The system contains two kinds of operation modes : "independent-supply mode" and "parallel-to-utility mode". In the independent-supply mode, the user can take the 110V AC source converted from the solar energy conversion system to supply the household machines. In the parallel-to-utility mode, this system can supply power in parallel to the utility system. The microprocessor 80196MC is used to control the whole system because the control circuit can be simplified and the control software can be updated easily under this fully digitalized control. The hardware that is used and the control method for the special output characteristics of the solar cell will be presented in the thesis. In the independent-supply mode , the output voltage can be kept constant under various loads and DC input ; in the parallel-to-utility mode, the system output current can be synchronized with the utility and the maximum power point can also be tracked. Finally, experimental results of a 1KW load test are recorded. Both modes of operation are functionally guaranteed.
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Kan, Po-Chung, and 甘伯仲. "Buoyant Solar Tracking System." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/33277885877116021986.
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碩士環球科技大學
環境資源管理所
101
Abstract This study aimed to develop a low cost buoyant solar tracking system, in order to enhance the efficiency of solar power generation. The buoyant solar tracking system contains two main modules. One is the automation photosensitive module consisting of the photosensitive element and automation control circuit of the control module; the other is buoyant module with water pumps and the leveling mechanism including buoyant balls. This design begins with the capture of sunlight by the photosensitive element, which passes over the signal to the automation module to control the water pumps, resulting in the difference of water levels in the East and West. The differential buoyancy causes the solar photovoltaic panels to synchronize with the angle of solar position, optimizing the power generation. Test results showed that the system can improve of 37.67% of the power generation of the solar cell panel.
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Chen, Yu-shu, and 陳昱樹. "Simulation and Fabrication of Fresnel Lens for Solar Lighting System and Solar Power System." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/59292253498834745056.
Full textAbstract:
碩士國立高雄第一科技大學
光電工程研究所
95
This thesis first part describe the Fresnel Lens apply to solar cells. The simulation 3D Dome-shaped on concentrator ratio 25X. For an acceptance angle of a = 1.5 deg and collection efficiency with 96.8%. Tolerate angle and discussion absorption efficiency and tolerance angle in different wavelength. Second part describe the Fresnel Lens apply to solar lighting system. For an acceptance angle of a = 0.2 deg and collection efficiency with 60%. We designed better efficiency of the visible light greater than ultraviolet light and infrared light on concentrator lens. Therefore the optical fiber absorb lesser ultraviolet light and infrared light, and discussion absorptive efficiency and incident angle of light guide on visible light. This thesis first part makes the Lens, the simulation as compared with product result, energy diagram and efficiency of solar energy spectra. Under sunlight, the focus point size is 3mm and we got a higher efficiency of visible light region.
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SHEN, KUO-WEI, and 沈國偉. "Dual axis solar tracing system." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4afq39.
Full textAbstract:
碩士國立宜蘭大學
電機資訊學院碩士在職專班
105
With the development of industry, dependence on oil is also increasing day by day, but the oil in the underground stock also with the depletion of time, But also because several times after the nuclear energy disaster，People start to think about the green and safe energy is the future trend，In general the most common application is the use of solar energy into electricity，The Taiwan government has begun to subsidize the development of solar energy, making the domestic application of solar energy is also becoming popular， but because the required area of solar energy is relatively large，Therefore, how to increase the solar module power generation is the need to solve the problem, but also the main purpose of this Thesis。 The main purpose of this system is to use PLC to control the bimodal stepping motor，Making biaxial and variable systems and utilizing the sunset moments and azimuths provided by the Central Meteorological Office，And the establishment of the database, after the operation makes the solar panels perpendicular to the sun, in order to improve the solar panels power generation capacity.
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Chen, Yung-Jen, and 陳詠仁. "The Solar Car Control system." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/64561273302783552699.
Full textAbstract:
碩士南台科技大學
電機工程系
95
ABSTRACT This thesis is researched the controls system by the electricity of solar energy car; It mainly is the result which is worth to the solar energy MPPT module, motor on the solar energy car and various parameters of battery to make the solar energy car reach an appearance manifestation. On the usage of system core, this research will be produced with a single Micro chip PIC 18F4620 to achieve retrieve the parameters. Distinguish the parameter wanted to retrieve among them for: Motor electric current, motor speed, MPPT module electric current, battery electric voltage, battery electric current, battery temperature .After finishing retrieving six parameter values, again make use of a graphic LCD display to present a data. The pilot of solar energy car can understand a solar energy car well in the usage of current conditions. Therefore, the origin studies medium, at the appearance used by pilot, is designed by retrieve various parameter of what MPPT module, motor and the value acquired by battery. Can let thus pilot clear car current function, then achieve effectively control. In addition, for the sake of various function of further well exertive car, the SD Card equiped on the solar energy car, can help the road that we go by all of the solar energy cars gaining various parameter a value, be used as a saved it use. By this design, not only can be used as a regulatory basis in the days to come for the parameter enactment of solar energy car ,but also make its function more perfect. The purpose could even know the part of breakdown from it, then abbreviated manpower, time depletion to attaining by maintain quickly. The way that this thesis designs is SD Card to is provided by the system which saved at that time of memory space, and it can make to analysis data by computer of the signal data that the SD Card saved, the PIC 18F4620 and the SD Card are used SPI mode of the series transmission to communicate. So hereafter be a solar energy car drive, the solar energy car electricity controls system can simultaneously carry on a solar energy car of system supervision, part again give the signal information saved record in the SD Card, hereafter can carry on analysis through the SD Card, after can make the function of solar energy car to more and more promote. Key words: MPPT, solar, signal chip, graphic LCD