SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The evolving space station program will be examined through a series of more specific studies: maintainability; research and technology in space; solar thermodynamics research and technology; program performance; onboard command and control; and research and technology road maps. The purpose is to provide comments on approaches to long-term, reliable operation at low cost in terms of funds and crew time.
The Centre for Organic Photonics & Electronics (COPE) at UQ has been successful in acquiring funding from the Australian Center for Advanced Photovoltaics (ACAP), which is the Australian partner of the Australia-US Institute for Advanced Photovoltaics (AUSIAPV). NREL is a key partner in AUSIAPV (along with other US research institutions (ASU, Sandia NL, LBNL, Stanford, Georgia Tech and UCSB). NREL will collaborate with COPE to advance the science and technology of organic materials for solar cell applications. COPE has significant programs in the development and understanding of new materials for organic optoelectronic applications and, in particular, for thin film bulk heterojunction (BHJ) solar cells and Organic Photodiodes (OPDs). NREL has significant established research programs in all aspects of organic photovoltaic technology and has well-developed expertise in the area of materials characterization, photocarrier transport measurements as well as device fabrication, scale-up and stability. This collaboration will combine the expertise of the two institutions to work towards demonstrating the scalability of organic materials for BHJ and OPD applications by measuring the fundamental properties of the materials as a function of processing and evaluating their performance and stability in photovoltaic devices under simulated illumination conditions. Currently, both NREL and UQ have individual organic material development and processing efforts and have independently demonstrated several prototype materials and device architectures as promising candidates for organic solar cells and OPDs. This CRADA will align these efforts building upon strengths of the two institutions to further design and demonstrate materials and device architectures to advance organic BHJ solar cells and OPDs. It should also be clearly noted that we foreshadow possible expansion of collaborative research activities between COPE and NREL, which currently lie outside the scope of the current statement of work, which will be amended as required by mutually executed written modifications to this CRADA.
The present paper deals with explosions in a magnetized solar plasma, known as flares, whose effects are seen throughout the electromagnetic spectrum, from gamma-rays through the visible and to the radio band. The diverse phenomena associated with flares are discussed, along with the physical mechanisms that have been advanced to explain them. The impact of solar flare research on the development of plasma physics and magnetohydrodynamics is noted. The rapid development of solar flare research during the past 20 years, owing to the availability of high-resolution images, detailed magnetic field measurements, and improved spectral data, is illustrated.
The research concerning lightweight solar array assemblies since 1970 is reported. A bibliography of abstracts of documents used for reference during this period is included along with an evaluation of available solar array technology. A list of recommended technology programs is presented.
The present review has the objective to cover major developments in American research related to solar energetic particles, both observational and theoretical, taking into account the period from late 1978 to late 1982. It is pointed out that particular progress has been made in the area of solar energetic particle composition with respect to elemental, isotopic, and the distribution of charge states. This progress is primarily the result of improved instrumentation available at a time of higher solar activity. An important aspect of solar particle studies is to understand the propagation of particles from the vicinity of the sun through interplanetary space to wherever the observing instruments are located. Almost all mathematical models for the transport of solar cosmic rays are derived in some sense from the same general Boltzmann or Vlasov equations. Attention is also given to advances related to an understanding of coronal propagation, and acceleration and injection processes.
NREL will be collaborating with the Participant on a United States - Australia Solar Energy Collaboration (USASEC) Project Number 1-USO034 "Tools for design and scale-up of solar thermochemical reactors." The grant funds for the Participant's 3.5 year project number 1-US034 commencing on 1 February 2013 have been awarded to the Participant by the Australian Renewable Energy Agency and NREL will be collaborating with the Participant during the final 28 months of this project. This project seeks to provide basic knowledge required to design solar thermochemical reactors able to perform the required energy conversions. In several proposed and demonstrated reactors, concentrated sunlight directly irradiates small solid particles suspended in fluid, enabling very high heat transfer rates to the particles which are the sites of chemical reaction. The reactors, therefore, involve the complex and couple dynamics of turbulent, chemically reacting, particle-laden flows and their interaction with concentrating solar radiation. A strong understanding of these coupled interactions will be crucial important in predicting and optimizing the performance of prototype reactors, but this understanding does not yet exist, since they have never been studied in any fundamental way. The project has a assembled an internationally leading team from The University of New South Wales (UNSW) and the University of Adelaide in Australia and the NREL in the United States to address this key gap in available know-how. The project will use U.S. Dept. of Energy (DOE) supercomputers, among the most powerful available worldwide, with cutting-edge software tools to perform first-principles simulations of the relevant interactions. These studies will be combined with detailed laser-based measurements in Australia to provide the first comprehensive databases concerning the governing phenomena in directly irradiated solar-thermochemical reactors. The outcomes will be the basic scientific knowledge, engineering knowhow and modeling tools necessary to design new reactor concepts and then scale up from the laboratory bench to practical size systems.
Non-fullerene acceptors based organic solar cells represent the frontier of the field, owing to both the materials and morphology manipulation innovations. Non-radiative recombination loss suppression and performance boosting are in the center of organic solar cell research. Here, we developed a non-monotonic intermediate state manipulation strategy for state-of-the-art organic solar cells by employing 1,3,5-trichlorobenzene as crystallization regulator, which optimizes the film crystallization process, regulates the self-organization of bulk-heterojunction in a non-monotonic manner, i.e., first enhancing and then relaxing the molecular aggregation. As a result, the excessive aggregation of non-fullerene acceptors is avoided and we have achieved efficient organic solar cells with reduced non-radiative recombination loss. In PM6:BTP-eC9 organic solar cell, our strategy successfully offers a record binary organic solar cell efficiency of 19.31% (18.93% certified) with very low non-radiative recombination loss of 0.190 eV. And lower non-radiative recombination loss of 0.168 eV is further achieved in PM1:BTP-eC9 organic solar cell (19.10% efficiency), giving great promise to future organic solar cell research.
Four major areas in solar cell research and technology were considered. The areas were: (1) the silicon cell; (2) the GaAs cell; (3) the multibandgap cell; and (4) novel ideas. In each area material research issues, cell research issues, and the cell technology that needs development are considered.
NREL and RhoTech will collaborate to bring long-lived, ultra-low-cost, high-performance solar water heaters (SWH) to market readiness. An existing RhoTech design uses seam-welded polymer thin films to make an unglazed thermosiphon, and this design will be modified to improve durability through ultraviolet and overheat protection, and to improve performance by adding a glazing to the collector. Two generations of the new glazed systems will be tested in the field, resulting in a robust market-ready SWH design that can be installed for under $1,000 without rebates.
This presentation provides summaries of three reports selected from a body of work that examines potential reliability challenges related to planning future power systems with higher solar photovoltaic (PV) penetrations in the western United States. The three topics covered are 1) Power system flexibility requirements and supply; 2) Resource adequacy and the capacity credit of solar; 3) Simulating distributed energy resource responses to transmission system-level faults considering IEEE 1547 performance categories on three major WECC transmission paths. The full reports and related resources are available at the project website, https://www.westernenergyboard.org/western-interstate-energy-board/barrier-mitigation-to-enhanced-distributed-solar-photovoltaic/. This presentation is targeted toward a technical audience. A companion policy presentation provides higher-level summaries of the same material.
The Solar Resource Calibration, Measurement, and Dissemination project supports the U.S. Department of Energy's Solar Energy Technologies Office (SETO) initiative to make solar energy cost-competitive with other forms of electricity by improving the tools and methods to measure and model solar radiation and therefore reduce uncertainty in predicting solar output and improve the bankability of solar projects. This project has three tasks that conduct research on advancing solar resource measurements and modeling: Task 1: Applied solar Radiation Measurements. Task 2: National Solar Radiation Data Base (NSRDB). Task 3: Knowledge Sharing. The National Renewable Energy Laboratory's (NREL's) Solar Radiation Research Laboratory (SRRL) activities ensure traceable solar measurements throughout the United States that are essential for project feasibility, due diligence, financing, and plant operations. The SRRL houses NREL's Baseline Measurement System (BMS), which provides a platform for improving the accuracy of solar measurements through research to improve the calibration and characterization of instruments and enable the development of new measurement technology and standards. The platform contains a variety of instruments measuring solar radiation and other meteorological parameters. Following best practices, BMS instruments are calibrated to ensure traceability to the World Radiometric Reference in compliance with ISO/IEC 17025 accreditation requirements. The BMS data sets are quality-controlled and made publicly available through the Measurement and Instrumentation Data Center website. The NSRDB is the most accessed public database of solar irradiance and associated weather parameters for use in energy modeling. It supports SETO's goals of reducing barriers to high penetrations of solar technologies by providing easy access to high-quality, foundational data essential for innovative product development and downstream modeling through the NSRDB website. Data are currently available for the contiguous United States and beyond for 20 years covering 1998-2017. The Physical Solar Model (PSM) that underpins the current NSRDB data sets is a unique physics-based model that has been developed at NREL and has opened the door to the use of next-generation satellite data sets for solar resource assessment and forecasting. Through the American Society for Testing Materials (ASTM) International and other international standards organizations, NREL continues to provide leadership in the development of standards that are relevant to the measurement and modeling of solar radiation for solar energy applications. Standards developed cover the calibration method of pyrheliometers (direct normal irradiance measurements), pyranometers (global horizontal irradiance measurements), spectroradiometers, ultraviolet radiometers, correct field deployment of these instruments, spectral distribution reference tables for photovoltaic modeling, and transfer of indoor calibrations. Further, NREL leads the International Energy Agency (IEA) Photovoltaic Power Systems Programme Task 16: Subtask 1, which focuses on the evaluation of current and emerging resource assessment methodologies. NREL and the IEA updated the Best Practices Handbook for the Collection and Use of Solar Resource Data for Solar Energy Applications, which is widely used by the solar industry.
This project has been in effect from July 25 th , 2008 to July 24 th , 2013. It supported 19 graduate students and 6 post-doctoral students and resulted in 23 publications, 7 articles in preparation, 44 presentations, and many other outreach efforts. Two representative recent publications are appended to this report. The project brought in more than $750,000 in cost share from North Carolina State University. The project funds also supported the purchase and installation of approximately 667,000 in equipment supporting solar energy research.
The return of samples from solar system bodies is becoming an essential element of solar system exploration. The recent National Research Council Solar System Exploration Decadal Survey identified six sample return missions as high priority missions: South-Aitken Basin Sample Return, Comet Surface Sample Return, Comet Surface Sample Return-sample from selected surface sites, Asteroid Lander/Rover/Sample Return, Comet Nucleus Sample Return-cold samples from depth, and Mars Sample Return [1] and the NASA Roadmap also includes sample return missions [2] . Sample collection methods that have been flown on robotic spacecraft to date return subgram quantities, but many scientific issues (like bulk composition, particle size distributions, petrology, chronology) require tens to hundreds of grams of sample. Many complex sample collection devices have been proposed, however, small robotic missions require simplicity. We present here the results of experiments done with a simple but innovative collection system for sample return from small solar system bodies.
This chapter describes the X-ray and gamma-ray imaging spectroscopy capabilities of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). It also outlines RHESSI’s major scientific accomplishments during the 16 years of operations from 2002 to 2018. These include unique contributions to solar flare research and to other aspects of solar physics (oblateness), astrophysics (magnetars), and Earth sciences (terrestrial gamma-ray flashes).
The study of solar reflector performance reported is related to a project in which solar collectors are to be provided for the solar heating and cooling system of an office building at NASA's Langley Research Center. The solar collector makes use of a liquid consisting of 50% ethylene glycol and 50% water. A conventional air-liquid heat exchanger is employed. Collector performance and solar insolation data are recorded along with air temperature, wind speed and direction, and relative humidity.
This presentation provides high-level summaries of three reports selected from a body of work that examines potential reliability challenges related to planning future power systems with higher solar photovoltaic (PV) penetrations in the western United States. The three topics covered are 1) Power system flexibility requirements and supply; 2) Resource adequacy and the capacity credit of solar; 3) Simulating distributed energy resource responses to transmission system-level faults considering IEEE 1547 performance categories on three major WECC transmission paths. The full reports and related resources are available at the project website, https://www.westernenergyboard.org/western-interstate-energy-board/barrier-mitigation-to-enhanced-distributed-solar-photovoltaic/. This presentation is targeted toward policy decision makers. A companion technical presentation provides more in-depth summaries of the same material.
The two major outcomes from this DOE supported collaboration between UbiQD and NREL were: 1) an expert analysis/modeling of the expected performance and cost of luminescent solar concentrating windows with quantum dot coatings, and 2) critical R&D characterization of materials and device performance analysis using equipment and processes that are too expensive for UbiQD to perform in-house. The latter also included third-party validation of the device performance with an NREL-certified conversion efficiency that was ultimately published. (see ACS Energy Lett. 2018 and recently ACS Appl. Energy Mater. 2020).
This study introduces a new technique to compute direct normal irradiance (DNI) for improving the National Solar Radiation Data Base (NSRDB). A finite-surface integration algorithm is developed to compute solar radiation in differential solid angles and efficiently infer its contribution to a surface perpendicular to the solar direction. A lookup table of cloud bi-directional transmittance distribution function (BTDF) is developed by use of the discrete ordinates radiative transfer (DISORT) model for possible solar and observing directions and various cloud optical and microphysical properties. In each solar incident direction, DNI is given by the cloud BTDFs from approximately 200 differential solid angles. The simulated DNI is calibrated and evaluated using surface observations at the National Renewable Energy Laboratory's (NREL's) Solar Energy Research Laboratory (SRRL) and the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) facility.