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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.

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At least 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

A Pseudo Planar Heterojunction Structure for Eco‐Friendly Printable Organic Solar Cells Achieving 19.05% Efficiency

Abstract Obtaining a well‐accurate vertical distribution active layer morphology through the air‐printing process is an essential task for achieving efficient scalable large‐area organic solar cells (OSCs). In this target, the desired and controllable pseudo planar heterojunction (PPHJ) active layer structure with suitable phase separation is developed by pre‐deposited D18‐Cl layer under the PM6:BTP‐eC9 film via an eco‐friendly manufacturing method. The addition of the D18‐Cl regulates molecular crystallization and leads to an ideal vertical stratification while simultaneously suppressing voltage loss, optimizing energetic disorder, and carrier management. Impressively, the optimal PPHJ devices perform superior power conversion efficiencies (PCEs) of 19.05% (100 nm), 17.33% (300 nm), and 14.14% (4 cm 2 ) compared to the BHJ devices. Importantly, the PPHJ OSCs also exhibit an impressive extrapolated T 80 (the time required to reach 80% of initial PCE) of long‐time storage and operational stability, as well as thermal stability.

Chemistry↗
DOE OSTI2022

Community-Scale Solar Deployment in the Northwest Arctic

NANA Regional Corporation (NRC, or NANA) was formed as an Alaska Native Corporation (ANC) pursuant to the Alaska Native Claims Settlement Act of 1971. Our lands cover 39,000 square miles of the Northwest Arctic region of Alaska. We partner closely with the Northwest Arctic Borough (NAB) and our 11 remote communities on numerous projects and activities, especially around clean energy initiatives that improve quality of life and help to reduce extremely high energy costs experienced by the communities in our region. Collectively, the regional partnership has developed numerous successful solar, wind, biomass, and energy storage, distribution upgrade, and efficiency projects. To further progress, we created the Northwest Arctic Energy Steering Committee to share and replicate these benefits across the region. NANA’s mission is to provide economic opportunities for our more than 13,500 Iñupiat shareholders and to protect and enhance NANA lands.

14 SOLAR ENERGY↗
DOE OSTI2025

Architectural Approaches for Integrating ADMS and DERMS: Challenges, Comparisons, and Real-World Use Cases

The electrical distribution landscape is rapidly transforming due to the proliferation of distributed energy resources (DERs) such as solar panels, wind turbines, battery storage systems, combined heat and power units, and electric vehicles, introducing variability and uncontrollability that traditional grid operators are ill-equipped to manage. This transformation is further accelerated by advancements in Information and Communication Technology infrastructure that connects control centers with end devices, demanding automation and a deeper understanding of new technologies by utility personnel. Advanced grid control techniques using system-level optimization, Artificial Intelligence, and Machine Learning at the enterprise level and distributed level are evolving to address these issues. There is also an opportunity to utilize the enormous data created by these new DER technologies in the grid. Advanced Distribution Management Systems (ADMS) and Distributed Energy Resource Management Systems (DERMS) are critical in addressing these challenges by automating grid operations and enhancing reliability. Given the relatively recent development of ADMS and DERMS, and the still relatively low level of ADMS and DERMS deployment in the industry, there is a notable deficiency in the comprehensive understanding of the challenges and benefits associated with these new technologies, especially with their complementary natures and integration architectures. This paper aims to bridge the knowledge gap in ADMS and DERMS integration, presenting three distinct integration architectures currently available, and discussing the challenges and benefits of each architecture to guide utilities, industry professionals, and researchers in optimizing grid management and decision-making processes for a resilient and efficient energy future.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

Resilient, Rural, and Revolutionary: Salisbury Square's Direct-Current Affordable Microgrid Community: Preprint

The technology to interconnect buildings with a dedicated direct-current (DC) power distribution network is in place today; what is missing is a turnkey approach to designing a DC microgrid - and the business models allowing such systems to be deployed, owned, and operated at scale. To close this gap, the Salisbury Square Development Team, comprising clean-energy experts, has engineered a resilient community DC microgrid for an affordable housing community in Randolph, Vermont. Ten single-family, occupant-owned residences and 12 multifamily rental units will share locally generated and stored solar energy via a DC power distribution bus capable of operating during extended grid outages. With a DC power distribution network in place, each home will be equipped with high-efficiency DC lighting and appliances, operating alongside alternating current (AC) appliances, even during an islanded mode of operation. To obtain a comprehensive understanding of what is possible and achievable, the Team collaborated with the local utility, regulatory agencies, a national laboratory, energy-as-service providers, and vendors. The collaborators evaluated microgrid typologies, business models, and energy modeling, and analyzed electrification and resilience. Further, the Team applied the URBANoptTM (Urban Renewable Building and Neighborhood optimization, NREL 2022) software development kit (SDK) to Salisbury Square's single-family and multifamily buildings to validate workflows and identify needs for advanced capability. This paper addresses the barriers to entry, scalability, and impact on residents and system ownership. It also examines the analysis that informed the design and engineering of the DC microgrid and the opportunities to streamline the process.

DER↗
DOE OSTI2019

Bidirectional reflection of semitransparent polytetrafluoroethylene (PTFE) sheets on a silver film

In our recent work, record-high solar reflectance (exceeding 99%) has been demonstrated by placing a layer of highly scattering, semitransparent polytetrafluoroethylene (PTFE) sheet on top of a silver film. This can significantly improve the performance of daytime radiative cooling system. Although a PTFE slab of 10-mm thick acts as an excellent diffuse reflector, it is unclear how this dual-layer structure made of a thin PTFE on a mirror-like reflector will alter the bidirectional reflection. Here, we report measurements of the bidirectional reflectance distribution function (BRDF) of the dual-layer structure using a laser scatterometer at the wavelength of 635 nm. Measurements of the BRDF and the bidirectional transmittance distribution function (BTDF) of free-standing PTFE sheets are also performed. The measured BRDF for a PTFE sheet as thin as 236 μm on Ag is essentially diffuse except at large incidence angles. A Monte Carlo ray-tracing method incorporating both surface scattering and volumetric scattering is developed to theoretically model the BRDF in order to elucidate the underlying mechanisms. Finally, the numerical model captures the main features and can be used to study the bidirectional properties for PTFE sheets thinner than what is experimentally available.

42 ENGINEERING↗
DOE OSTI2018

Using Time-of-Flight SIMS to Investigate Group V Dopant Distribution in CdTe

Enabling continued development of polycrystalline CdTe solar cells with open-circuit voltages approaching 1 V requires new dopants and processes to increase acceptor concentrations and minority-carrier lifetimes. We have investigated multiple Group V dopants in single- and polycrystalline CdTe materials as well as Cl, using numerous dopant incorporation and activation strategies. The diffusion kinetics and spatial distribution of the dopants are revealed with a combination of 1-D standard depth-profiling and high-resolution 3-D tomography with time-of-flight secondary-ion mass spectrometry. For all cases where the dopant is incorporated during growth, including vapor-transport deposition, closespaced sublimation, and molecular-beam epitaxy, the dopant concentration is not enhanced at grain boundaries. When the dopant is incorporated through a post-growth incorporation process, fast grain-boundary diffusion leads to an enhanced dopant concentration at grain boundaries. Although both methods are applicable, in-situ incorporation offers control of dopants and devices independent of diffusion kinetics, grain structure, and grain-boundary chemistry.

14 SOLAR ENERGY↗
DOE OSTI2023

Photometry of Outer Solar System Objects from the Dark Energy Survey. I. Photometric Methods, Light-curve Distributions, and Trans-Neptunian Binaries

We report the methods of and initial scientific inferences from the extraction of precision photometric information for the >800 trans-Neptunian objects (TNOs) discovered in the images of the Dark Energy Survey (DES). Scene-modeling photometry is used to obtain shot-noise-limited flux measures for each exposure of each TNO, with background sources subtracted. Comparison of double-source fits to the pixel data with single-source fits are used to identify and characterize two binary TNO systems. A Markov Chain Monte Carlo method samples the joint likelihood of the intrinsic colors of each source as well as the amplitude of its flux variation, given the time series of multiband flux measurements and their uncertainties. A catalog of these colors and light-curve amplitudes A is included with this publication. We show how to assign a likelihood to the distribution q(A) of light-curve amplitudes in any subpopulation. Using this method, we find decisive evidence (i.e., evidence ratio <0.01) that cold classical (CC) TNOs with absolute magnitude 6 < H$_{r}$ < 8.2 are more variable than the hot classical (HC) population of the same H$_{r}$, reinforcing theories that the former form in situ and the latter arise from a different physical population. Resonant and scattering TNOs in this H$_{r}$ range have variability consistent with either the HCs or CCs. DES TNOs with H$_{r}$ < 6 are seen to be decisively less variable than higher-H$_{r}$ members of any dynamical group, as expected. More surprising is that detached TNOs are decisively less variable than scattering TNOs, which requires them to have distinct source regions or some subsequent differential processing.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Energy Systems Integration: NREL + EATON

Electrification of transportation fleets provides an opportunity for optimizing multiple distributed energy resource (DER) technologies, such as solar and energy storage. NREL is partnering with Eaton to evaluate control strategies for managing electric bus (E-bus) fleets for grid services. The project team will develop a replicable platform for evaluating EV fleet management and quantifying benefits from grid services.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

The Effects of Turbulence on Heliosheath Ions and Implications for Energetic Neutral Atoms

The distribution of ions in the heliosheath—the region between the heliospheric termination shock and the heliopause—is important for understanding remote observations of energetic neutral atoms (ENAs). The ion distributions were estimated previously based on hybrid simulations of the heating and evolution of solar wind and interstellar pickup ions across the solar wind termination shock, but these estimates only provide the distributions near the shock. In this work, we use self-consistent hybrid kinetic simulations to investigate the effects of turbulence on ion distributions in the heliosheath. The simulations are compared against Voyager observations, constraining the feasible amplitude and compressibility of turbulence. We find that the heating due to turbulent dissipation can lead to a significant increase in the temperature of thermal solar wind ions. Both turbulent velocity fluctuations and the heating of solar wind ions increase the charge-exchange source for ENAs at low energies (around 100 eV), where current ENA models underpredict observations by more than an order of magnitude. However, the effects of turbulence are likely not strong enough to fully explain these discrepancies.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Through Concentration Profiling of Heterojunction Solar Cells

Electrochemical capacitance–voltage profiling has been used to examine heterojunction solar cells based on single-crystal silicon. Specific features of the electrochemical capacitance–voltage profiling of modern multilayer heterojunction solar cells have been analyzed. The distribution profiles of majority carriers across the whole thickness of the samples were obtained, including, for the first time, those in layers of conducting indium tin oxide.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Nonstationarity of the Efficiency Coefficient and Heating Temperatures of Water in Flat-Plate Solar Collectors

A one-dimensional nonstationary three-element distributed thermal model of a flat-plate collector with allowance for time variation of the temperatures through the “thickness” of the elements and along the length of the solar collector (SC) has been developed and software-implemented. The main data in this model consist of the thermophysical and overall parameters of the collector elements, heat carrier inlet velocity, solar radiation density, and ambient and sky temperature. To decrease the calculation variants, the variation ranges of mass flow of the heat carrier and its flow velocity were estimated for the characteristic parameters of the heat-removal channels of flat-plate SCs. It has been found that the specific mass flows of water in flat-plate SCs are 2.5–10 g/(s m{sup 2}), and the water flow velocity is 0.0005–0.002 m/s. It is shown that the instantaneous efficiency coefficient and temperature of the heat carrier can fall outside stationary values within 1–3 h. However, the daily efficiency coefficients of the SC do not fall outside the stationary values even within a day. The developed flat-plate SC model can be used to estimate the influence of the thermophysical and overall parameters of the elements, as well as the parameters of the environment, on its thermophysical characteristics when developing flat-plate SCs and methods for experimentally determining their characteristics.

14 SOLAR ENERGY↗
DOE OSTI2022

Performance Evaluation of Distributed Energy Resource Management Systems Using Software- and Hardware-in-the-Loop

Distributed energy resource management systems (DERMS) are an important emerging technology for coordinating distributed energy resources (DERs) integrated in power distribution networks. These solutions implement a software platform to monitor, control, and coordinate DERs in real time to provide aggregate grid services to the electric utility or distribution system operator. To move DERMS technology forward, research and performance validation in a laboratory environment are needed to ensure proper function of DERMS prior to field deployment. This presentation presents a generic hardware-in-the-loop (HIL) platform to evaluate performance of DERMS using software-in-the-loop (SIL) and power HIL. The platform provides realistic testing in a laboratory environment, including accurate modeling of full-scale distribution systems, DERMS software controllers, and at-power distributed energy resources (DERs), such as solar and battery inverters. Two case studies are presented to demonstrate how the platform can be used independently as an integrated development and validation approach for different projects. Laboratory testing results are included to showcase the voltage regulation performance of each study and the benefits of implementing such a platform for DERMS evaluation.

DERMS↗
DOE OSTI2022

Evaluation of WRF-Solar Cloud Forecast Using the NSRDB: Preprint

Cloud forecast is a crucial component in predicting solar irradiance from numerical weather prediction (NWP) models. Assessing cloud properties from the NWP models requires significant work due to the need for high-quality data, spatial analysis covering model extent, and detailed analysis of model performance for different types of clouds. This study presents an evaluation of the WRF-Solar cloud forecast using the National Solar Radiation Database (NSRDB). We propose an evaluation framework applied to a single model prediction as well as ensemble-based forecasts. Various cloud detection metrics are calculated when comparing with the satellite-derived dataset. The mismatched clouds from the WRF-Solar model are quantified using nine cloud types classified by cloud top height and cloud optical depth. The results based on the WRF-Solar forecasts covering the entire U.S. for the full year of 2018 shows mismatched cloud frequency in the range of 8% - 46% for thick and high-level (deep convective) to thin and low-level (cumulus) clouds.

cloud mask forecast↗
DOE OSTI2023

All-polymer organic solar cells with nano-to-micron hierarchical morphology and large light receiving angle

Distributed photovoltaics in living environment harvest the sunlight in different incident angles throughout the day. The development of planer solar cells with large light-receiving angle can reduce the requirements in installation form factor and is therefore urgently required. Here, thin film organic photovoltaics with nano-sized phase separation integrated in micro-sized surface topology is demonstrated as an ideal solution to proposed applications. All-polymer solar cells, by means of a newly developed sequential processing, show large magnitude hierarchical morphology with facilitated exciton-to-carrier conversion. The nano fibrilar donor-acceptor network and micron-scale optical field trapping structure in combination contributes to an efficiency of 19.06% (certified 18.59%), which is the highest value to date for all-polymer solar cells. Furthermore, the micron-sized surface topology also contributes to a large light-receiving angle. A 30% improvement of power gain is achieved for the hierarchical morphology comparing to the flat-morphology devices. These inspiring results show that all-polymer solar cell with hierarchical features are particularly suitable for the commercial applications of distributed photovoltaics due to its low installation requirement.

14 SOLAR ENERGY↗
DOE OSTI2024

Solar Energy Technical Publications Catalog: Solar Thermal Technology

The research and development described in these documents was conducted within the U.S . Department of Energy's (DOE) Solar Thermal Technology Program. The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axis tracking mirrors) to focus the sun's radiant energy onto a single, tower- mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating work fluid. Receiver temperatures range from l00 degrees C in low-temperature troughs to over 1500 degrees C in dish and central receiver systems. The Solar Thermal Technology Program is directing efforts to advance and improve each system concept through solar thermal materials, components, and subsystems research and development and by testing and evaluation. These efforts are carried out with the technical direction of DOE and its network of field laboratories that works with private industry. Together they have established a comprehensive, goal-directed program to improve performance and provide technically proven options for eventual incorporation into the nation's energy supply. To successfully contribute to an adequate energy supply at reasonable cost, solar thermal energy must be economically competitive with a variety of other energy sources. The Solar Thermal Technology Program has developed components and system-level performance targets as quantitative program goals. These targets are used in planning research and development activities, measuring progress, assessing alternative technology options, and developing optimal components. These targets are pursued vigorously to ensure a successful program. This catalog represents part of an effort to provide information on publications about solar thermal research and development activities conducted by DOE's laboratories. Publications listed include technical and research reports and special publications. The following national laboratories are represented in this edition: Sandia National Laboratories, Solar Energy Research Institute, Jet Propulsion Laboratory. This catalog is a product of the DOE Solar Technical Information Program, which is dedicated to providing information to scientific and industrial users in ways most convenient and useful to them. This catalog focuses on solar thermal technologies, and its purpose is to keep the scientific and industrial communities informed of the latest developments in federally sponsored research in this technology.

140000* -- Solar Energy↗
DOE OSTI2020

Making Better Use of On-Site PV Generation: Direct Distribution of DC Power in Buildings

With the increasing availability of Direct Current (DC) power from on-site solar systems, building designers now have the option of direct distribution of DC power to energy storage systems and end-use loads such as lighting, electronics, and motors. Research shows that direct-DC can reduce building distribution losses by 5-15%, while improving power reliability. A readily available way to implement direct-DC distribution is Power over Ethernet (PoE), which typically has provided low-voltage DC to power office equipment such as WiFi access points. With recent updates to the PoE standard, equipment such as network-controlled LED lighting, thin client and computer workstations, HVAC controllers, fans, motors, and actuators can now be powered by PoE and are commercially available. This paper presents results from a DOE-funded project that is demonstrating PoE technologies and describes a DC modeling and design tool that is intended to help building designers properly evaluate and design DC distribution systems in buildings. The tool provides designers of DC power systems with estimates of both power system losses and indirect effects on building heating and cooling. The results of this research demonstrate that the design methods and products are available to implement DC power in buildings today.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Digital Assurance Checklist for Homeowners and Installers

This document provides a comprehensive Digital Assurance Checklist for securing behind-the-meter energy assets, focusing on both installers and homeowners. As distributed energy resources (DERs) such as solar PV and battery storage become integral to residential energy systems, cybersecurity emerges as a critical component of reliability and safety. The guide outlines actionable steps for installers during pre-installation, commissioning, and post-installation phases, emphasizing practices like network segmentation, credential management, firmware validation, and homeowner education. For homeowners, the document introduces a tiered approach to cyber hygiene—from essential measures like strong Wi-Fi credentials and automatic updates to advanced strategies such as network segmentation, DNS filtering, and intrusion detection. By adopting these practices, stakeholders can mitigate cyber risks, safeguard energy infrastructure, and ensure resilient, secure operation of DER systems. Additional resources and references to industry standards are included to support implementation.

99 - GENERAL AND MISCELLANEOUS↗
DOE OSTI2026

Digital Assurance Checklist for Homeowners and Installers

This document provides a comprehensive Digital Assurance Checklist for securing behind-the-meter energy assets, focusing on both installers and homeowners. As distributed energy resources (DERs) such as solar PV and battery storage become integral to residential energy systems, cybersecurity emerges as a critical component of reliability and safety. The guide outlines actionable steps for installers during pre-installation, commissioning, and post-installation phases, emphasizing practices like network segmentation, credential management, firmware validation, and homeowner education. For homeowners, the document introduces a tiered approach to cyber hygiene—from essential measures like strong Wi-Fi credentials and automatic updates to advanced strategies such as network segmentation, DNS filtering, and intrusion detection. By adopting these practices, stakeholders can mitigate cyber risks, safeguard energy infrastructure, and ensure resilient, secure operation of DER systems. Additional resources and references to industry standards are included to support implementation.

99 - GENERAL AND MISCELLANEOUS↗