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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Development of a Computer Program for Analyzing Preliminary Aircraft Configurations in Relationship to Emerging Agility Metrics

This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition, one study illustrates the module's ability to optimize a configuration's agility performance.

Bauer, Brent↗
NASA NTRS2003

Cabin Air Quality Dynamics On Board the International Space Station

Spacecraft cabin air quality is influenced by a variety of factors. Beyond normal equipment offgassing and crew metabolic loads, the vehicle s operational configuration contributes significantly to overall air quality. Leaks from system equipment and payload facilities, operational status of the atmospheric scrubbing systems, and the introduction of new equipment and modules to the vehicle all influence air quality. The dynamics associated with changes in the International Space Station's (ISS) configuration since the launch of the U.S. Segment s laboratory module, Destiny, is summarized. Key classes of trace chemical contaminants that are important to crew health and equipment performance are emphasized. The temporary effects associated with attaching each multi-purpose logistics module (MPLM) to the ISS and influence of in-flight air quality on the post-flight ground processing of the MPLM are explored.

Perry, J. L.↗
NASA NTRS1980

Orbiter S-band direct link system verification test report

Space-to-ground S-band communications system compatibility and performance tests were performed for the various radio frequency links. These tests consisted of the various uplink and downlink signal combinations (data rates) for the phase modulation system and both realtime and playback data rates for the frequency modulated downlink systems. In addition, tests involving encryption/decryption, Doppler, and acquisition were performed. Results show that the S-band transponder for the space shuttle orbiter is compatible with the S-band equipment of the AFSCF/RTS (Air Force Satellite Control Facility/Remote Tracking Station). It is also concluded that the performance of the orbiter-AFSCF/RTS direct link exceeds the required performance and that this communications link will meet the system requirements of the Space Transportation System.

Vermillion, B. K.↗
DOE OSTI2021

Field-Array Benchmark of Commercial Bifacial PV Technologies with Publicly Available Data

We present results for a 75-kW field array deployed with rows of 5 different commercially available bifacial technologies. Four PERC (multi and mono) and 1 Silicon Heterojunction manufacturers are represented. Reference strings of equivalent monofacial PV modules are also installed in the 10-row field. High accuracy string-level DC monitoring and module-level measurements have been recorded for six months. Analysis indicates performance within expectation, with a cumulative model mean error within +/- 2% for both bifacial and monofacial models and cumulative bifacial energy gain between 6-9%. A custom-module to measure shading loss from the torque-tube was installed. One month data shows up to 6% irradiance non-uniformity. A fixed-tilt test-site with 3 years of bifacial data is also presented, with a bifacial gain of 3%.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2021

AGGREGATE: dAta-driven modelinG preservinG contRollable dEr for outaGe mAnagemenT and rEsiliency (Final Report)

The AGGREGATE project team successfully developed and validated various modules for outage management. Brief summaries of each module are provided to showcase their strength for outage management and restoration for a distribution system with a high penetration of connected distribution energy resources (DERs). In recent years, inverter-based DERs have been widely deployed in distribution system. A most of behind-the-meter (BTM) solar power generation is not visible to the utility. The data-driven DER and load estimation modules are using machine learning (ML) and artificial intelligence (AI) to manage this issue, which provides an opportunity for distribution system operators (DSOs) to operate systems and make decisions in real-time for a distribution system with a high penetration of DERs deployed. Also, the estimated DER and true load can be further leveraged in network aggregation and cold-load pick up estimation for reducing the computing complexity and providing for fast restoration. After load demand and DER power generations have been estimated, the information will support topology and state estimation (SE). The topology estimation module demonstrated the viability of mixed integer linear programming (MILP) formulation to estimate the most likely operational radial topology and outage sections using power flow measurements, historical/estimated load and DERs data and smart meter ping measurements. Formulation includes continuous (power flow, load and DERs data) and binary measurements (smart meter ping measurements) in a single formulation. Errors in continuous data and binary data are modeled as normal distribution and Bernoulli distribution, respectively. In the future distribution grid, the power injection from controllable DERs will be essential for efficient and resilient grid operation. However, determining the optimal DER injections and restoration actions is dependent on knowledge of the system states. State estimation (SE), already the cornerstone of transmission energy management systems, will become commonplace in distribution management systems as more measurements become available from deployment of automated metering infrastructure (AMI). Observability analysis is the first step in SE, as it determines the sufficiency of the available measurements for accurately estimating the current system states. A new type of pseudo-measurement called a Correlational Measurement (CM) is introduced in this module, to enhance the observability of the system to enable more accurate SE. CMs encapsulate knowledge of correlation between demand patterns for similar classes of loads as well as injection patterns for same-technology renewable DERs. During grid contingency scenarios, DERs have been traditionally disconnected, without any fault ride-through capabilities. However, with new regulations and better technology, it is feasible for these resources to contribute to the grid’s restoration after an adverse event and hence enhance resilience. The controllability module proposes a two-step restoration scheme for the power system restoration process by leveraging additional degrees of freedom in power electronics interfaced DERs for mitigating voltage problems. In a resilience mode without the utility system, the distribution grid relies on DERs to serve critical load. In such a severe event with multiple faults on the distribution feeders, actuation of various protective devices (PDs) divides the distribution system into electrical islands. The undetected actuated PDs due to fault current contributions from DERs can delay the restoration process, thereby reducing the system resilience. The Advanced Outage Management (AOM) and the Advanced Feeder Restoration (AFR) modules developed in this project provide improved system resilience with multiple DERs. AOM identifies the faulted sections and actuated PDs in a distribution system with DERs by incorporating smart meter data. The most credible outage scenario including fault locations, PD actuations, and fault indicator (FI) failures is identified by a set of binary integer linear programming incorporating hypotheses. The AFR module serves to restore a distribution system with available energy resources taking into consideration the availability of utility sources and DERs. By partitioning the system into islands, critical load will be served with the available generation resources within islands based on the solution of a MILP. When the utility systems become available, the optimal path will be determined by a spanning tree search algorithm that reconnects these islands back to substations and restores the remaining load. The transmission and distribution (T&D) co-simulation module was used to validate the effect of a control action performed on the distribution side assets as it propagates to the transmission side. This ensures that the control action performed results in a feasible operating point on both the transmission and the distribution system. In addition to validation, the team used the T&D co-simulation module to demonstrate how distribution system assets can be used to mitigate issues on the transmission system. Specifically, the team demonstrated that appropriate switching operations on the distribution side can alleviate the line overload condition on the transmission side without causing new operational constraint violations.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Modulating electrode utilization in lithium-ion cells with silicon-bearing anodes

The stability of silicon-containing anodes can, in principle, be extended by constraining these electrodes to limited states of lithiation. Partial utilization of the anode lessens the volume changes experienced by silicon particles during cycling, which can mitigate mechanisms of performance degradation. In full-cells, anode utilization can be modulated by adjusting the relative capacities of the negative and positive electrodes - the N/P ratio. Here, we examine how the N/P ratio affects the long-term stability of Si-based full-cells, and investigate how this parameter would impact the cost and energy of realistic Li-ion cells. Here, we show that, for some configurations, cell failure due to rapid anode degradation can only by avoided at higher N/P ratios. The price of this enhanced stability is accelerated impedance rise at the cathode. Surprisingly, when electrode expansion is taken into account, increasing N/P ratio can actually increase the specific energy and energy density of silicon-rich Li-ion cells.

25 ENERGY STORAGE↗
NASA NTRSDate not supplied

Modal Test and Model Correlation of NASA Plum Brook Station Mechanical Vibration Facility Head Expander –Lessons Learned from the Perspective of an Early-Career Engineer

In preparation for the Sierra Nevada Corporation’s (SNC) Dream Chaser spacecraft vibration test campaign at the Mechanical Vibration Facility (MVF) at NASA Plum Brook Station (PBS) in Sandusky, Ohio, a test-verified model of MVF is needed in order to be able to perform accurate pretest analysis used for determining response limits and abort levels. MVF was designed to vibration test MPCV Orion and was used to perform the system level vibration test of the European Service Module Structural Test Article (E-STA) in 2016. MVF is comprised of an 18 ft diameter annulus table that is driven with sixteen hydraulic vertical actuator assemblies and four hydraulic horizontal actuator assemblies, which allow it to perform single axis vibration testing in the vertical axis and in each of the two orthogonal horizontal axes without the need for reconfiguring the test article. A head expander for the MVF Table has been designed and built that fills in the center opening providing a continuous flat mounting surface with a maximum diameter of 16.25feet that expands the vibration testing capabilities of MVF. The MVF Table with this head expander will be used during the SNC Dream Chaser spacecraft vibration test campaign. Therefore, a critical element in a test-verified model of the MVF will be a test correlated finite element model (FEM) of the head expander. To obtain this, engineers from the Structural Dynamics Lab (SDL) at NASA Glenn Research Center (GRC) in Cleveland, Ohio performed a modal pretest analysis, conducted a modal test in July 2019, and most recently correlated the head expander finite element model to the modal test data up to 300 Hz. From the initial test preparations to the final delivery of a correlated finite element model, all efforts mentioned were led by the same early-career engineers at NASA GRC. From the viewpoint of an early-career engineer, lessons learned about modal pretest analysis, modal testing, and finite element model correlation of the MVF Table expander head will be presented and discussed. This will include the importance of understanding the limitations of using uncorrelated finite element models in the modal pretest analysis and planning, the importance of orthogonality metrics in judging adequacy and accuracy of test mode shapes, and the importance of having the FEM match the as built hardware in the model correlation effort.

Emma L Pierson↗
NASA NTRS1993

Design and performance oof space station photovoltaic radiators

The design and performance of the Space Station Freedom Photovoltaic (PV) Power Module Thermal Control System radiators is presented. The PV Radiator is of a single phase pumped loop design using liquid ammonia as the coolant. Key design features are described, including the base structure, deployment mechanism, radiator panels, and two independent coolant loops. The basis for a specific mass of 7.8 kg/sqm is discussed, and methods of lowering this number for future systems are briefly described. Key performance paramters are also addressed. A summary of test results and analysis is presented to illustrate the survivability of the radiator in the micrometeoroid and orbital debris environment. A design criterion of 95% probability of no penetration of both fluid loops over a 10 year period is shown to be met. Methods of increasing the radiator survivability even further are presented. Thermal performance is also discussed, including a comparison of modeling predictions with existing test results. Degradation in thermal performance due to exposure to atomic oxygen and ultraviolet radiation in the low Earth orbit environment is presented. The structural criteria to which the radiator is designed are also briefly addressed. Finally, potential design improvements are discussed.

White, K. Alan↗
NASA NTRS1999

NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Lewis Research Center (LeRC), and Pratt & Whitney (P&W). This development team operates under the guidance of the NCC steering committee. The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration.

Liu, Nan-Suey↗
DOE OSTI2024

Experimental Investigation on Heating Performance of a Cold Climate Thermoelectric-Assisted Heat Pump

To accelerate the electrification of air source heat pumps (ASHPs) in cold climates across the United States, various initiatives have been launched to enhance the effectiveness of ASHPs. One avenue of research involves incorporating thermoelectric (TE) technology into vapor compression refrigeration cycles. This study aims to assess the heating performance of a cold climate ASHP by employing TE modules as a liquid line subcooler. The tested system is a nominal 4.5-ton split heat pump utilizing R410A, equipped with a scroll compressor and an accumulator. An electronic expansion valve was employed for both cooling and heating modes. Two configurations of TE sub-coolers, one utilizing 2 TE bundles and the other 4 TE bundles, were integrated into the liquid line of the tested system. The heating performance of these configurations was evaluated. The results revealed that activating the TE subcooler led to a notable increase in total heat capacity, reaching 1318 W at -15.0 °C and 1164 W at -19.0 °C. The corresponding TE coefficients of performance (COPs) were 1.76 and 1.63, respectively. The activation of the TE sub-cooler resulted in a slight reduction in the overall system COP, with a decrease ranging from -2.6% to -4.2% for these two temperatures. The system COPs were measured at 2.10 and 1.86 for -15.0 °C and -19.0 °C, respectively. This prototype demonstrated a significant augmentation in heating capacity with a minimal sacrifice in COP.

Hu, Yifeng↗
DOE OSTI2021

Incorporating Electrochemical Halide Oxidation into Drift-Diffusion Models to Explain Performance Losses in Perovskite Solar Cells under Prolonged Reverse Bias

Partial shading of a solar module can induce a set of cells within the module to operate under reverse bias. Studies have shown that metal halide perovskite solar cells with a wide variety of compositions and contacts exhibit interesting behavior in reverse bias that includes both reversible performance loss and non-reversible degradation. In this paper, an advanced drift-diffusion approach incorporating an electrochemical term to explain the short-circuit, open circuit and fill factor losses that are experimentally measured after prolonged reverse bias is used. It is shown that holes can tunnel into the perovskite due to sharp band bending near the contact, accumulate within the bulk of the perovskite absorber, and trigger the oxidation of halides to form neutral halogens. The density of neutral halogens is much higher in reverse bias because there are hardly any electrons available to reduce the iodine. The resulting halogens act as bulk recombination centers. While the interstitial halogen density does decay when the cell is operated in forward bias, permanent degradation can occur if the iodine diffuses out of the perovskite layer. Finally, the ways in which changing parameters such as the mobile ion density or the series resistance at the contact can influence device performance and stability are discussed.

degradation↗
NASA NTRS1972

A portable hydrazine attitude propulsion test system

The portable hydrazine attitude propulsion module is described that was designed and developed to support the attitude control pitch axis simulation tests performed on an air bearing table for the thermoelectric outer planet spacecraft program. The propulsion module was a self-contained, liquid hydrazine propulsion system from which the exhausted gases were generated within the catalyst bed of either of two nominal 0.22-N opposing thrusters. The module, which was designed for convenient assembly onto and removal from an air bearing table, was tested to establish its operational safety. This test history and the very conservative design of the module enabled it to be man-rated for operation in the presence of personnel. The report briefly summarizes the system operations during air bearing table tests, presents a detailed description of the propulsion module hardware, and discussing the system evolution.

Moynihan, P. I.↗
DOE OSTI2019

A General Approach for Lab‐to‐Manufacturing Translation on Flexible Organic Solar Cells

Abstract The blossoming of organic solar cells (OSCs) has triggered enormous commercial applications, due to their high‐efficiency, light weight, and flexibility. However, the lab‐to‐manufacturing translation of the praisable performance from lab‐scale devices to industrial‐scale modules is still the Achilles' heel of OSCs. In fact, it is urgent to explore the mechanism of morphological evolution in the bulk heterojunction (BHJ) with different coating/printing methods. Here, a general approach to upscale flexible organic photovoltaics to module scale without obvious efficiency loss is demonstrated. The shear impulse during the coating/printing process is first applied to control the morphology evolution of the BHJ layer for both fullerene and nonfullerene acceptor systems. A quantitative transformation factor of shear impulse between slot‐die printing and spin‐coating is detected. Compelling results of morphological evolution, molecular stacking, and coarse‐grained molecular simulation verify the validity of the impulse translation. Accordingly, the efficiency of flexible devices via slot‐die printing achieves 9.10% for PTB7‐Th:PC 71 BM and 9.77% for PBDB‐T:ITIC based on 1.04 cm 2 . Furthermore, 15 cm 2 flexible modules with effective efficiency up to 7.58% (PTB7‐Th:PC 71 BM) and 8.90% (PBDB‐T:ITIC) are demonstrated with satisfying mechanical flexibility and operating stability. More importantly, this work outlines the shear impulse translation for organic printing electronics.

Meng, Xiangchuan↗
DOE OSTI2019

Energy efficient photonic millimeter-wave generation using cascaded polarization modulators

A filter-less millimeter-wave generation scheme consisting of four polarization modulators in series, each followed by a polarizer is proposed to achieve optoelectronic frequency octupling. The cascade of polarization modulator and polarizer provides an intensity modulator whose biasing condition can be set by the polarizer angle and polarization state of the input light to each polarization modulator. A theoretical analysis of the architecture is performed using a transfer function method and validated by industry-standard software simulation tools. The circuit shows high potential in achieving desired performance with lower input RF power when compared to the another configuration based on a generalized Mach–Zehnder interferometer structure. Although the operating range in terms of applied RF drive becomes narrow, low RF input operation can be achieved by this circuit. The effect of imbalances in the key circuit parameters is also investigated in terms of electrical side harmonic suppression ratio.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Holistic modeling framework of demand response considering multiti-mescale uncertainties for capacity value estimation

Demand response (DR) is regarded as an effective tool to mitigate the operational uncertainties and enhance the reliability of power supply in smart grids. However, with the time-varying attribute, to what extent DR could be committed is a major concern for utilities. This paper proposes a new approach to assess the capacity value (CV) of DR with a methodological framework developed for the uncertainty modeling of DR. The novelty of this framework is its inclusion of both physical and human-related analyses in DR programs, which allows the characterization of DR variability to be accurate for the CV estimation. To achieve this, the demand-side activities in DR are disaggregated into several modules as load usage, contract selection and actual performance. Based on their intrinsic properties, different parametric models are proposed to represent the impact of each technical/social factor on the availability of DR. The parameters of these models are determined using learning based algorithms to adapt to various behavior patterns of consumers. The outputs of the framework will serve as the quantifiers of DR capability and are integrated into reliability-based CV evaluation. The results of case studies verify the effectiveness of the proposed methodology.

Capacity value↗
DOE OSTI2018

Multiscale finite element modeling of sheet molding compound (SMC) composite structure based on stochastic mesostructure reconstruction

Predicting the mechanical behavior of the chopped carbon fiber Sheet Molding Compound (SMC) due to spatial variations in local material properties is critical for the structural performance analysis but is computationally challenging. Such spatial variations are induced by the material flow in the compression molding process. In this work, a new multiscale SMC modeling framework and the associated computational techniques are developed to provide accurate and efficient predictions of SMC mechanical performance. The proposed multiscale modeling framework contains three modules. First, a stochastic algorithm for 3D chip-packing reconstruction is developed to efficiently generate the SMC mesoscale Representative Volume Element (RVE) model for Finite Element Analysis (FEA). A new fiber orientation tensor recovery function is embedded in the reconstruction algorithm to match reconstructions with the target characteristics of fiber orientation distribution. Second, a metamodeling module is established to improve the computational efficiency by creating the surrogates of mesoscale analyses. Third, the macroscale behaviors are predicted by an efficient multiscale model, in which the spatially varying material properties are obtained based on the local fiber orientation tensors. Our approach is further validated through experiments at both meso- and macro-scales, such as tensile tests assisted by Digital Image Correlation (DIC) and mesostructure imaging.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Energy savings with outdoor temperature-based smart ventilation control strategies in advanced California homes

We simulated the energy performance of smart ventilation controls based on outdoor temperature in homes located in California climate regions, designed to comply with the 2016 Title 24, Part 6 California Energy Code prescriptive requirements. The smart controls shift ventilation rates in time, but ensure an annual occupant pollutant exposure equal to, or less than, what would be experienced in a home with a constant ventilation rate equal to the whole house target airflow in the ASHRAE Standard 62.2-2016. Annual simulations of previously developed prototype homes with validated ventilation models were conducted via co-simulation of EnergyPlus with CONTAM. Controller performance varied substantially by climate zone, airtightness and house prototype. Smart controls were generally ineffective in Climate Zone 1 (Arcata) due to its lack of a cooling season and low diurnal temperature swings. The most successful smart controls used parameters pre-calculated using an optimization routine. In order to better inform state energy policy, we also determined savings weighted by the amount of new home construction in each climate. The best controls averaged about one-third of ventilation-related energy savings that increased to about 48–55% when weighted. Annual average savings were about 650–700 kWh/year for the best controllers. The vast majority of site energy savings were for heating end-uses (>90% of total savings). Whole house ventilation rates increased between 0% and 42%, with typical increases in the 15–20% range. Finally, the best-performing control strategies shifted ventilation rates seasonally and modulated flows within each season. Peak concentrations during low ventilation times were kept below an exposure level of 3, well below the maximum of 5 required to avoid acute exposure issues.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Stabilizing Ni-rich layered cathode for high-voltage operation through hierarchically heterogeneous doping with concentration gradient

High-nickel LiNi x Mn y Co 1-x-y O 2 (NMC) cathodes have demonstrated superior energy density, yet their stability is compromised under high voltage conditions. To address this, here we propose a strategy of heterogeneous doping with a concentration gradient, specifically through Sr–Zr co-modification. We synthesized Ni-rich NMC particles featuring several micron-sized secondary particles composed of micron-sized primary grains. This design aims to harness the structural robustness of single-crystalline grains and the favorable diffusion kinetics of polycrystalline secondary particles. Systematic characterization using a combination of electrochemical measurements and synchrotron analytics reveals an intriguing pattern of hierarchically heterogeneous Sr–Zr co-doping. It demonstrates a depth-dependent concentration gradient at the secondary particle level and competing dopant segregation over the buried grain boundaries. This unique characteristic creates opportunities for enhancing battery performance, particularly by optimizing precursors and implementing advanced modulation techniques. We also investigate the dissolution and precipitation of the cathode's transition metal cations upon high-voltage cycling. These insights suggest that a tailored compositional variation can be a viable approach to effectively design the next-generation high-Ni NMC cathode materials for high-voltage lithium batteries.

36 MATERIALS SCIENCE↗

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