Browsing by Subject "Renewable energy sources"
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Item Item Analysis of a novel thermoelectric generator in the built environment(2011-08) Lozano, Adolfo; Webber, Michael E., 1971-; Schmidt, Philip S.This study centered on a novel thermoelectric generator (TEG) integrated into the built environment. Designed by Watts Thermoelectric LLC, the TEG is essentially a novel assembly of thermoelectric modules whose required temperature differential is supplied by hot and cold streams of water flowing through the TEG. Per its recommended operating conditions, the TEG nominally generates 83 Watts of electrical power. In its default configuration in the built environment, solar-thermal energy serves as the TEG’s hot stream source and geothermal energy serves as its cold stream source. Two systems-level, thermodynamic analyses were performed, which were based on the TEG’s upcoming characterization testing, scheduled to occur later in 2011 in Detroit, Michigan. The first analysis considered the TEG coupled with a solar collector system. A numerical model of the coupled system was constructed in order to estimate the system’s annual energetic performance. It was determined numerically that over the course of a sample year, the solar collector system could deliver 39.73 megawatt-hours (MWh) of thermal energy to the TEG. The TEG converted that thermal energy into a net of 266.5 kilowatt-hours of electricity in that year. The second analysis focused on the TEG itself during operation with the purpose of providing a preliminary thermodynamic characterization of the TEG. Using experimental data, this analysis found the TEG’s operating efficiency to be 1.72%. Next, the annual emissions that would be avoided by implementing the zero-emission TEG were considered. The emission factor of Michigan’s electric grid, RFCM, was calculated to be 0.830 tons of carbon dioxide-equivalent (CO2e) per MWh, and with the TEG’s annual energy output, it was concluded that 0.221 tons CO2e would be avoided each year with the TEG. It is important to note that the TEG can be linearly scaled up by including additional modules. Thus, these benefits can be multiplied through the incorporation of more TEG units. Finally, the levelized cost of electricity (LCOE) of the TEG integrated into the built environment with the solar-thermal hot source and passive ground-based cold source was considered. The LCOE of the system was estimated to be approximately $8,404/MWh, which is substantially greater than current generation technologies. Note that this calculation was based on one particular configuration with a particular and narrow set of assumptions, and is not intended to be a general conclusion about TEG systems overall. It was concluded that while solar-thermal energy systems can sustain the TEG, they are capital-intensive and therefore not economically suitable for the TEG given the assumptions of this analysis. In the end, because of the large costs associated with the solar-thermal system, waste heat recovery is proposed as a potentially more cost-effective provider of the TEG’s hot stream source.Item Economic analysis of wind and solar energy sources of Turkey(2011-05) Erturk, Mehmet; Groat, Charles G.; Jablonowski, Christopher J.Renewable energy sources have become very popular in the last years in electricity generation thanks to the technological developments, the increase in the price of fossil fuels and the environmental concerns. These factors have also prompted Turkey to utilize her very rich renewable energy sources to meet the demand increasing around 7% annually. In this study, solar and wind energy potential of Turkey is analyzed in terms of its economics to find out whether these sources are real alternatives to fossil fuels in electricity generation. Before this analysis, wind and solar energy technologies and costs and wind and solar energy potential of Turkey are discussed. Then, models are set up for five technologies which are onshore wind, offshore wind, solar PV, solar trough and solar tower technologies models to calculate cash flows which are used to calculate payback, NPV, IRR, LCE and shut-down price to conduct economic analysis. In addition to base case scenario, uncertainty analysis is done for the most promising technologies which are onshore wind and solar tower technologies by evaluating NPV and LCE under uncertain environment. The main finding of these analyses is that only onshore wind projects are attractive in Turkey; none of other technologies is attractive. However, with a minor increase in the regulated price for solar thermal electricity, tower plant projects will also be attractive.Item Performance analysis of renewable energy sources(Texas Tech University, 1997-05) Bayne, Stephen B.Renewable energy such as wind and solar is a clean source of energy that can be integrated with convention ways of producing energy. Power utility companies are looking at ways to integrate renewable energy with convention methods. The Central and South West (CSW) company is investigating the role of solar and wind energy in a utility system. Although CSW is a profit making company, the CSW renewable project is research based with a goal of helping the company understand renewable energy for future use. The CSW project gives the opportunity to investigate the problems that are encounter when operating renewable energy sources and also to come up with solutions. One approach to help analysis a system is to develop model for the system. A mathematical model for a grid connected wind farm is developed and modeled in Mathcad. A circuit model representing a wind connected wind farm is also developed. The transient behavior of a wind farm under different conditions is also investigated. The availability of the turbines at the wind farm is calculated and the results are presented. The caused of blade passing and its effect on the turbine power and current is also investigated. The problems encountered since the turbines were on line will also be discussed. A method was developed which shows why the hub height wind velocity can be used to evaluate the power output of a wind farm.Item Simultaneous electricity, bioethanol, and algal biodiesel production using microbial fuel cell(2012-05) Kerls, Marci; Karim, M. Nazmul; Vaughn, Mark W.With an ever increasing world population, the energy needs for this population will only grow. A renewable sustainable energy is needed to maintain the world’s energy consumption. A study of a device that would be capable of simultaneously producing bioelectricity and bioethanol and algae oil was conducted. The microbial fuel cell was catalyzed with Chlorella vulgaris and Saccharomyces bayanus in the cathode and anode, respectively. A series of four experimental runs were conducted, along with three different control experiments. The algae growing in the microbial fuel cell was also monitored, and the algae was harvested for lipid content. The yeast in the anode was run in batch and continuous conditions over the course of the experiments and samples were taken to measure ethanol concentrations. Polarization curves were obtained to calculate the power density and current density, and intermittent energy harvesting was performed. The MFC with yeast and algae in the anode and cathode, respectively, achieved a power density of 70.61 ± 12.41 mW/m2, and a current density of 155.02 ± 31.23 mA/m2. The volumetric productivity of the ethanol was found to be 0.49±0.37 g l-1 hr-1, and an algae oil content of 13 ± 1.7 grams of lipids per grams of algae biomassItem Utility interface design for distributed renewable energy sources(Texas Tech University, 2000-12) Radhakrishnan, GuruprakashThe basic idea of the project is to design and build single-phase inverters, and use them to interface distributed renewable energy sources to the utility grid. Photovoltaic elements can be used on rooftops to capture solar energy, which are used to generate DC voltage. It is proposed to exploit this energy to create AC power, which is then fed into the utility. Besides, this energy could also be used to independently power some low-rated installations (a sixty-Watt light bulb is being used in our case). The project revolves around the design of the power electronics circuit topology and the requisite controls. Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) are used in the form of an H-Bridge to form the single-phase inverter, the output of which would be subject to Pulse Width Modulation (PWM) to produce a sinusoidal wave, to be synchronized to the utility. A micro-controller (Motorola's HC12) is being used for the purpose. The magnitude and phase angle of this synthetically generated voltage are adjusted with respect to the utility voltage, thus achieving total control over the real and reactive power.