27 research outputs found

    ALTERNATIVE ENERGY SOURCES - INTEGRATION OF POWER GENERATION SYSTEMS INTO A MICROGRID AT CLEMSON UNIVERSITY AND AN ATMOSPHERIC THERMODYNAMIC DRIVEN MECHANICAL CLOCK

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    Non-renewable energy sources such as coal, crude oil, and natural gas are being consumed at a brisk pace which is promoting a worldwide energy crisis. The burning of fossil fuels produces greenhouse gases such as carbon dioxide and nitrous oxides as well as soot which contribute to atmospheric pollution. Although fossil fuels will continue to be available for many decades, the amount of petroleum remaining in the earth and its associated cost remains an open issue. The utilization of green energy such as solar and wind offer renewable and pollution free sources. A worldwide shift is slowly underway towards the inclusion of renewable energy sources to generate electrical and mechanical power. To meet this emerging societal demand, research into alternative energy sources such as solar, wind, and thermodynamic power generation is underway at Clemson University. This research encompasses two renewable energy strategies: a solar-based electrical microgrid, and an atmospheric thermodynamic driven mechanical clock. The concept of an electrical microgrid at Clemson University has been investigated as it promotes a renewable energy source to help realize a \u27net zero\u27 campus. For this case study, solar energy is harvested from the photovoltaic panels atop the Fluor Daniel Engineering Innovation Building which are capable of producing 15 kW of DC power at the full solar insolation rating. The electrical power produced varies throughout the day depending on the available solar irradiation and seasons. Next, compressed air energy storage has been evaluated using the generated electric power to operate an electric motor driven piston compressor. The compressed air is then stored under pressure and supplied to a natural gas driven Capstone C30 microturbine with attached electric power generator. In this approach, the compressed air facilitates the turbine\u27s rotor-blade operated compression stage resulting in direct energy savings. The compressed air energy storage mitigates the intermittency of solar power and provides a continuous energy input to the microturbine over selected time periods. In this thesis, a series of mathematical models have been developed for the solar panels, an air compressor, the pneumatic storage tank, and the microturbine as they represent the key microgrid system components. An illustrative numerical analysis was then performed to evaluate the feasibility and energy efficiency improvements. The experimental and simulation results indicated that 127.75 watts of peak power were delivered at 17.5 volts and 7.3 amps from each solar panel. The average DC power generation over a 24-hour time period from 115 panels was 75 kW which is equivalent to 30 kW of AC power from the inverter which could run a 5.2 kW reciprocating compressor for approximately 5 hours storing 1,108 kg of air at a 1.2 MPa pressure. The operation of the Capstone C30 microturbine was then simulated using a 0.31 kg/s mass flow rate with 100 air/fuel ratio. A case study indicated that the microturbine, when operated without compressed air storage, consumed 11.16 kg of gaseous propane for 30 kW∙hr of energy generation. In contrast, the microturbine operated in conjunction with solar supplied air storage could generate 50.84 kW∙hr of electrical energy for similar amount of fuel consumption. The study indicated an 8.1% of efficiency improvement in energy generated for the system which utilized compressed air energy storage over the traditional approach. An atmospheric driven mechanical Atmos clock manufactured by Jaeger LeCoultre has been investigated due to its capability to harvest energy based on climatic temperature and/or pressure changes to power the clock\u27s mechanisms. The clock\u27s bellows is the power unit which winds the on-board mainspring. The unwinding of this mainspring provides torque to run the gear train, the escapement, and the torsional pendulum. A detailed analysis of the Atmos 540 clock dynamics has been performed using a library of derived mathematical models which describe the bellows\u27 power generation, potential energy of the mainspring, gear train, escapement, and torsional pendulum. Experimental data has been collected using multiple sensors synchronized within the LabVIEW environment from National Instruments. For this thesis, the mathematical models have been simulated using Matlab/Simulink and validated with the gathered experimental results. The linear motion of the bellows was nearly 6 mm which winds the mainspring over a temperature range of 290-292K. The maximum potential energy of the mainspring was 57e-03J, or 0.67e-06 watts over a 24-hour time period. The minute hand rotation was observed to be 6 degrees/min. The captured crutch motion indicated a `hold\u27 position for a significant portion of the time (22 sec) and `impulse\u27 motion for a small portion of the time (8 sec) every 30 seconds in opposite directions. The findings indicated miniscule torque requirement to run the clock. In terms of green energy, the bellows motion is thermo-mechanical energy harvesting

    Operating Principles, Common Questions, and Performance Data for an Atmospheric Driven Atmos Clock

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    The elegance of the Atmos clock and the curiosity of mankind in self-operational mechanical systems have propelled this time device into our collective desire for more knowledge. The search for a self-winding time piece, based on normal atmospheric fluctuations, was pursued for centuries by horologists with the well-known clock proposed by J. L. Reutter and commercialized by Jaeger LeCoultre. This clock has generated numerous discussions throughout the years as noted in past Bulletin articles and other correspondences within the time keeping community. In this paper, the operating principles of the Atmos clock will be reviewed using fundamental science and engineering principles. Next, key questions and experimental observations will be discussed in light of the operating concepts to clarify the clock’s performance. Finally, an extensive database will be introduced which was gathered through physical measurements and data recording of an Atmos 540 clock

    Energy Harvesting from Atmospheric Variations - Theory and Test

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    The last two decades have offered a dramatic rise in the use of digital technologies such as wireless sensor networks that require small isolated power supplies. Energy harvesting, a method to gather energy from ambient sources including sunlight, vibrations, heat, etc., has provided some success in powering these systems. One of the unexplored areas of energy harvesting is the use of atmospheric temperature variations to obtain usable energy. This paper investigates an innovative device to extract energy from atmospheric variations using ethyl chloride filled mechanical bellows. The apparatus consists of a bellows filled with ethyl chloride working against a spring in a closed and controlled environment. The bellows expand/contract depending upon the ambient temperature and the energy harvested is calculated as a function of the bellows’ length. The experiments showed that 6 J of energy may be harvested for a 23 degree Celsius change in temperature. The numerical results closely correlated to the experimental data with a deviation of 1%. In regions with high diurnal temperature variation, such an apparatus may yield approximately 250 uW depending on the ambient temperature range

    Nature's Autonomous Oscillators

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    Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology

    Design and Analysis of a Mechanical Driveline with Generator for an Atmospheric Energy Harvester

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    The advent of renewable energy as a primary power source for microelectronic devices has motivated research within the energy harvesting community over the past decade. Compact, self-contained, portable energy harvesters can be applied to wireless sensor networks, Internet of Things (IoT) smart appliances, and a multitude of standalone equipment; replacing batteries and improving the operational life of such systems. Atmospheric changes influenced by cyclical temporal variations offer an abundance of harvestable thermal energy. However, the low conversion efficiency of a common thermoelectric device does not tend to be practical for microcircuit operations. One solution may lie in a novel electromechanical power transformer integrated with a thermodynamic based phase change material to create a temperature/pressure energy harvester. The performance of the proposed harvester will be investigated using both numerical and experimental techniques to offer insight into its functionality and power generation capabilities. The atmospheric energy harvester consists of a ethyl chloride filled mechanical bellows attached to an end plate and constrained by a stiff spring and four guide rails that allow translational motion. The electromechanical power transformer consists of a compound gear train driven by the bellows end plate, a ratchet-controlled coil spring to store energy, and a DC micro generator. Nonlinear mathematical models have been developed for this multi-domain dynamic system using fundamental engineering principles. The initial analyses predicted 9.6 mW electric power generation over a 24 hour period for ±1°C temperature variations about a nominal 22°C temperature. Transfer functions were identified from the lumped parameter models and the transient behavior of the coupled thermal-electromechanical system has been studied. A prototype experimental system was fabricated and laboratory tested to study the overall performance and validate the mathematical models for the integrated energy harvester system. The experimental results agree with the numerical analyses in behavioral characteristics. Further, the power generation capacity of 30 mW for a representative electrical resistance load and emulated rack input which correspond to 50 cyclic bidirectional temperature variations (~175 hours of field operation) validated the simulation models. This research study provides insight into the challenges of designing an electromechanical power transformer to complement an atmospheric energy harvester system. The mathematical models estimated the behavior and performance of the integrated harvester system and establishes a foundation for future optimization studies. The opportunity to power microelectronic devices in the milliwatt range for burst electric operation or with the use of supercapacitors/batteries enables global remote operation of smart appliances. This system can assist in reducing/eliminating the need for batteries and improving the operational life of a variety of autonomous equipment. Future research areas have been identified to improve the overall system capabilities and implement the harvester device for real-world applications

    Dickey-Lincoln School Lakes Project Power Alternatives Study Draft Report : Task 1 through 4

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    This report presents the detailed findings of Tasks 1 through 4 of the Dickey-Lincoln School Lakes Project Power Alternatives Study undertaken for the New England Division of the Corps of Engineers, by Acres American Incorporated, Consulting Engineers of Buffalo, New York under the terms of Contract Number DACW33-76-C-0047. Earlier reports on Task 1 dated July 1976, on Task 2 dated January 1977 and on Task 3 dated March 1977 have been incorporated virtually unchanged into this Task 4 report

    NASA Tech Briefs, October 1996

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    Topics covered include: Sensors; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Reports

    African Handbook of Climate Change Adaptation

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    This open access book discusses current thinking and presents the main issues and challenges associated with climate change in Africa. It introduces evidences from studies and projects which show how climate change adaptation is being - and may continue to be successfully implemented in African countries. Thanks to its scope and wide range of themes surrounding climate change, the ambition is that this book will be a lead publication on the topic, which may be regularly updated and hence capture further works. Climate change is a major global challenge. However, some geographical regions are more severly affected than others. One of these regions is the African continent. Due to a combination of unfavourable socio-economic and meteorological conditions, African countries are particularly vulnerable to climate change and its impacts. The recently released IPCC special report "Global Warming of 1.5º C" outlines the fact that keeping global warming by the level of 1.5º C is possible, but also suggested that an increase by 2º C could lead to crises with crops (agriculture fed by rain could drop by 50% in some African countries by 2020) and livestock production, could damage water supplies and pose an additonal threat to coastal areas. The 5th Assessment Report produced by IPCC predicts that wheat may disappear from Africa by 2080, and that maize— a staple—will fall significantly in southern Africa. Also, arid and semi-arid lands are likely to increase by up to 8%, with severe ramifications for livelihoods, poverty eradication and meeting the SDGs. Pursuing appropriate adaptation strategies is thus vital, in order to address the current and future challenges posed by a changing climate. It is against this background that the "African Handbook of Climate Change Adaptation" is being published. It contains papers prepared by scholars, representatives from social movements, practitioners and members of governmental agencies, undertaking research and/or executing climate change projects in Africa, and working with communities across the African continent. Encompassing over 100 contribtions from across Africa, it is the most comprehensive publication on climate change adaptation in Africa ever produced

    Proceedings of the 14th Aerospace Mechanisms Symposium

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    Technological areas covered include aviation propulsion, aerodynamic devices, and crew safety; space vehicle propulsion, guidance and control; spacecraft deployment, positioning, and pointing; spacecraft bearings, gimbals, and lubricants; and large space structures. Devices for payload deployment, payload retention, and crew extravehicular activity on the space shuttle orbiter are also described

    Innovation for maintenance technology improvements

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    A group of 34 submitted entries (32 papers and 2 abstracts) from the 33rd meeting of the Mechanical Failures Prevention Group whose subject was maintenance technology improvement through innovation. Areas of special emphasis included maintenance concepts, maintenance analysis systems, improved maintenance processes, innovative maintenance diagnostics and maintenance indicators, and technology improvements for power plant applications
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