Download or read book Advanced Thermophotovoltaic Cells Modeling Optimized for Use in Radioisotope Thermoelectric Generators RTGs for Mars and Deep Space Missions written by Bradley P. Davenport and published by . This book was released on 2004-06-01 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: To accommodate the need for power on deep space missions, satellites must carry a source capable of providing adequate power for the life of the mission. This is currently done using radioisotope thermoelectric generators (RTGs). Current RTGs consist of a heat source, Pu-238, and a thermocouple that inefficiently converts heat into electricity. To improve the overall efficiency of RTGs, a better thermoelectric converter is needed to replace the thermocouple. This thesis examines the possible use of thermophotovoltaic (TPV) cells in RTGs. Two cells were developed and optimized for the spectrum from a 1300K blackbody that simulates the spectrum of an RTG heat source. Current TPV cells are built and tested with different thicknesses and doping levels to the most efficient design, an expensive and time-consuming method. This thesis presents a model that can predict the output of a cell under various spectra. The model can easily be changed to simulate different cell thicknesses and doping levels, and it can be changed to simulate cells of different materials. The models presented in this thesis were built using the Silvaco Virtual Wafer Fabrication software package. To prove the capabilities of this software package in designing TPV models, an initial cell was designed using a well-documented material: gallium arsenide (GaAs). Voltage-current characteristics and frequency response data were recorded from this model and compared with experimental data from a similar cell. Once the model was verified, more exotic materials could be examined: gallium antimonide (GaSb) and indium gallium arsenide (InGaAs). As with the GaAs cell model, the GaSb and InGaAs models were first optimized for the AM0 spectrum and compared to experimental results. Programs were written using Matlab to run iterations of Silvaco to change layer thicknesses and doping levels. Other programs also were used to help determine the most efficient TPV cell design. (41 figures, 48 refs.)
Download or read book A Collection of the AIAA International Communications Satellite Systems Conference and Exhibit Technical Papers written by and published by . This book was released on 2004 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Collection of the 22nd AIAA International Communications Satellite Systems Conference and Exhibit Technical Papers written by and published by AIAA (American Institute of Aeronautics & Astronautics). This book was released on 2004 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Toward High Efficiency Radioisotope Thermophotovoltaic System by Spectral Control written by Xiawa Wang and published by . This book was released on 2017 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the design, modeling, and measurement results of a radioisotope thermophotovoltaic system (RTPV) using a two-dimensional photonic crystal emitter and low bandgap thermophotovoltaic (TPV) cell to realize spectral control. The RTPV generator aims to use the decay heat released by plutonium-238 fuel to heat up the emitter to incandescence and convert the infrared radiation to electricity in the TPV cell. With spectral control, high energy photons above the cell bandgap ([lambda] 2.25 [mu]m for InGaAsSb cell) are emitted to produce more electrical power while low energy photons ([lambda] 2.25 [mu]m) in far infrared are suppressed to reduce waste heat. We validated a system simulation using the measurements of a prototype system powered by an electrical heater equivalent to one plutonium fuel pellet. The thermal insulation design used multilayer insulation, which was found to be both efficient and chemically compatible with the photonic crystal emitter. We compared the system performance using a photonic crystal emitter to the one using a polished flat tantalum emitter and found that spectral control with the photonic crystal was four times more efficient. Based on the simulation, we further extended the design and performance estimates to real life RTPV generators optimized for both space and terrestrial applications. With the experimentally tested InGaAsSb TPV cell, the system efficiency can potentially reach above 8% with a specific power of 7.5 W/kg. With more advanced InGaAs monolithic-integrated-modules, the system efficiency can reach around 20% with a specific power above 17 W//kg.
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1996 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ALSEP Termination Report written by James R. Bates and published by . This book was released on 1979 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Emissivity Tuned Emitter for RTPV Power Sources written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Every mission launched by NASA to the outer planets has produced unexpected results. The Voyager I and II, Galileo, and Cassini missions produced images and collected scientific data that totally revolutionized our understanding of the solar system and the formation of the planetary systems. These missions were enabled by the use of nuclear power. Because of the distances from the Sun, electrical power was produced using the radioactive decay of a plutonium isotope. Radioisotopic Thermoelectric Generators (RTGs) used in the past and currently used Multi-Mission RTGs (MMRTGs) provide power for space missions. Unfortunately, RTGs rely on thermocouples to convert heat to electricity and are inherently inefficient (≈ 3-7% thermal to electric efficiency). A Radioisotope Thermal Photovoltaic (RTPV) power source has the potential to reduce the specific mass of the onboard power supply by increasing the efficiency of thermal to electric conversion. In an RTPV, a radioisotope heats an emitter, which emits light to a photovoltaic (PV) cell, which converts the light into electricity. Developing an emitter tuned to the desired wavelength of the photovoltaic is a key part in increasing overall performance. Researchers at the NASA Glenn Research Center (GRC) have built a Thermal Photovoltaic (TPV) system, that utilizes a simulated General Purpose Heat Source (GPHS) from a MMRTG to heat a tantalum emitter. The GPHS is a block of graphite roughly 10 cm by 10 cm by 5 cm. A fully loaded GPHS produces 250 w of thermal power and weighs 1.6 kgs. The GRC system relies on the GPHS unit radiating at 1200 K to a tantalum emitter that, in turn, radiates light to a GaInAs photo-voltaic cell. The GRC claims system efficiency of conversion of 15%. The specific mass is around 167 kg/kWe. A RTPV power source that utilized a ceramic or ceramic-metal (cermet) matrix would allow for the combination of the heat source, canister, and emitter into one compact unit, and allow variation in size and shape to optimize temperature and emission spectra.
Download or read book Mars written by Viorel Badescu and published by Springer Science & Business Media. This book was released on 2009-12-07 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: th th Mars, the Red Planet, fourth planet from the Sun, forever linked with 19 and 20 Century fantasy of a bellicose, intelligent Martian civilization. The romance and excitement of that fiction remains today, even as technologically sophisticated - botic orbiters, landers, and rovers seek to unveil Mars’ secrets; but so far, they have yet to find evidence of life. The aura of excitement, though, is justified for another reason: Mars is a very special place. It is the only planetary surface in the Solar System where humans, once free from the bounds of Earth, might hope to establish habitable, self-sufficient colonies. Endowed with an insatiable drive, focused motivation, and a keen sense of - ploration and adventure, humans will undergo the extremes of physical hardship and danger to push the envelope, to do what has not yet been done. Because of their very nature, there is little doubt that humans will in fact conquer Mars. But even earth-bound extremes, such those experienced by the early polar explorers, may seem like a walk in the park compared to future experiences on Mars.
Download or read book Beyond Earth written by Asif A. Siddiqi and published by National Aeronautis & Space Administration. This book was released on 2018 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a completely updated and revised version of a monograph published in 2002 by the NASA History Office under the original title Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes, 1958-2000. This new edition not only adds all events in robotic deep space exploration after 2000 and up to the end of 2016, but it also completely corrects and updates all accounts of missions from 1958 to 2000--Provided by publisher.
Download or read book Advanced Hybrid Solar Cell Approaches for Future Generation Ultra high Efficiency Photovoltaic Devices written by Jongwon Lee and published by . This book was released on 2014 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing the conversion efficiencies of photovoltaic (PV) cells beyond the single junction theoretical limit is the driving force behind much of third generation solar cell research. Over the last half century, the experimental conversion efficiency of both single junction and tandem solar cells has plateaued as manufacturers and researchers have optimized various materials and structures. While existing materials and technologies have remarkably good conversion efficiencies, they are approaching their own limits. For example, tandem solar cells are currently well developed commercially but further improvements through increasing the number of junctions struggle with various issues related to material interfacial defects. Thus, there is a need for novel theoretical and experimental approaches leading to new third generation cell structures. Multiple exciton generation (MEG) and intermediate band (IB) solar cells have been proposed as third generation alternatives and theoretical modeling suggests they can surpass the detailed balance efficiency limits of single junction and tandem solar cells. MEG or IB solar cell has a variety of advantages enabling the use of low bandgap materials. Integrating MEG and IB with other cell types to make novel solar cells (such as MEG with tandem, IB with tandem or MEG with IB) potentially offers improvements by employing multi-physics effects in one device. This hybrid solar cell should improve the properties of conventional solar cells with a reduced number of junction, increased light-generated current and extended material selections. These multi-physics effects in hybrid solar cells can be achieved through the use of nanostructures taking advantage of the carrier confinement while using existing solar cell materials with excellent characteristics. This reduces the additional cost to develop novel materials and structures. In this dissertation, the author develops thermodynamic models for several novel types of solar cells and uses these models to optimize and compare their properties to those of existing PV cells. The results demonstrate multiple advantages from combining MEG and IB technology with existing solar cell structures.
Download or read book Spacecraft Power Systems written by Mukund R. Patel and published by CRC Press. This book was released on 2023-12-12 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition of Spacecraft Power Systems is a comprehensive coverage of the fundamentals, design trades, components, controls, and operations of spacecraft power systems based on the real-world design and operations of spacecraft that have successfully flown for decades. It also includes emerging high-voltage, high-power systems for in-space propulsion for interplanetary travel. With new and updated chapters, sections, and discussions, the second edition covers up-to-date high-voltage, MW-scale electric propulsion, updated PV and battery systems, spacecraft power components, power electronics, and their architectures and operations. This book also presents the latest in spacecraft design processes and trades, controls, operations, and protection. This book is intended for senior undergraduate and graduate students in mechanical, aerospace, and electrical engineering taking courses in Space Systems, Space Engineering, and Spacecraft Power Systems, as well as for practicing aerospace and power engineers and managers who are designing, developing, and operating spacecraft power systems.
Download or read book Fundamentals of Renewable Energy Processes written by Aldo Vieira da Rosa and published by Academic Press. This book was released on 2009-05-07 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are hearing a LOT about renewable energy these days! But unlike most available resources on alternative energy that focus on politics and economic impacts, da Rosa's practical guide, Fundamentals of Renewable Energy Processes, is dedicated to explaining the scientific and technological principles and processes that enable energy production from safe, renewable, clean sources. Advances in the renewable energy sphere are proceeding with an unprecedented speed, and in order for the world's alarming energy challenges to be solved, solid, up-to-date resources addressing the technical aspects of renewables are essential. This new, updated 2e of da Rosa's successful book continues to give readers all the background they need to gain a thorough understanding of the most popular types of renewable energy—hydrogen, solar power, biomass, wind power, and hydropower—from the ground up. The latest advances in all these technologies are given particular attention, and are carefully contextualized to help professionals and students grasp the "whys and hows" behind these breakthroughs. Discusses how and why the most popular renewable energy sources work, including wind, solar, bio and hydrogen Provides a thorough technical grounding for all professionals and students investigating renewable energy The new 2e of a highly regarded guide written by an internationally renowned pioneer
Download or read book Radioisotopic Power Generation written by William R. Corliss and published by . This book was released on 1964 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Photovoltaic Modules and Their Applications written by G. N. Tiwari and published by Royal Society of Chemistry. This book was released on 2010 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presently there is no single publication available which covers the topics related to photovoltaic (PV) or photovoltaic thermal (PV/T) technologies, thermal modelling, CO2 mitigation and carbon trading. This book disseminates the current knowledge in the fundamentals of solar energy, photovoltaic (PV) or photovoltaic thermal (PV/T) technologies, energy security and climate change and is aimed at undergraduate and postgraduate students and professionals. The main emphasis of the book is on the design, construction, performance and application of PV and PV/T from the electricity and thermal standpoint. Hot topics covered in the book include: energy security of a nation, climate change, CO2 mitigation and carbon credit earned by using PV or PV/T technologies (Carbon Trading). This information will prove helpful in filling the gap between the researchers and professionals working on the application of photovoltaic and global climate change. It also covers economic, cost effective and sustainable aspects of photovoltaic technologies. The book gives a detailed history of the new technological developments in PV/T systems worldwide with system photographs and references and elaborates on the fundamentals of hybrid systems and their performances with thermal modelling. Energy and exergy analysis, techno-economic analysis and carbon trading are key chapters for research professionals. The book also includes important case studies to aid understanding of the subject for all readers.
Download or read book Recent Advances in Mechanical Engineering written by Anil Kumar and published by Springer Nature. This book was released on 2021-05-25 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the select proceedings of the second International Conference on Recent Advances in Mechanical Engineering (RAME 2020). The topics covered include aerodynamics and fluid mechanics, automation, automotive engineering, composites, ceramics and polymers processing, computational mechanics, failure and fracture mechanics, friction, tribology and surface engineering, heating and ventilation, air conditioning system, industrial engineering, IC engines, turbomachinery and alternative fuels, machinability and formability of materials, mechanisms and machines, metrology and computer-aided inspection, micro- and nano-mechanics, modelling, simulation and optimization, product design and development, rapid manufacturing technologies and prototyping, solid mechanics and structural mechanics, thermodynamics and heat transfer, traditional and non-traditional machining processes, vibration and acoustics. The book also discusses various energy-efficient renewable and non-renewable resources and technologies, strategies and technologies for sustainable development and energy & environmental interaction. The book is a valuable reference for beginners, researchers, and professionals interested in sustainable construction and allied fields.
Download or read book Nuclear Batteries and Radioisotopes written by Mark Prelas and published by Springer. This book was released on 2016-08-04 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains the physics of nuclear battery operation. It provides a comprehensive background that allows readers to understand all past and future developments in the field. The supply and cost of radioisotopes for use in applications (focused on nuclear batteries) are covered in the initial sections of the text. The interaction of ionizing radiation with matter is discussed as applied to nuclear batteries. The physics of interfacing the radioisotopes to the transducers which represent the energy conversion mechanism for nuclear batteries are described for possible nuclear battery configurations. Last but not least the efficiencies of nuclear battery configurations are discussed combined with a review of the literature on nuclear battery research.
