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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Laboratory Testing and Performance Characterization of the High Efficiency Dehumidification System (HEDS) Technology

The high efficiency dehumidification system (HEDS) is a unique air handling unit (AHU) design with two water coils. Connected in series, these water coils can sensibly reheat the airstream after it is cooled and dehumidified, thereby mitigating (or sometimes eliminating) the need for conventional sensible reheat with additional energy from hot water, electric resistance or steam coils. Another unique design feature is the size of the HEDS primary cooling coil. While typical AHU cooling coils have a 6-row geometry, the HED's cooling coil has a deeper 10-row geometry enabling discharge air dew point temperatures at or below 55 degrees F despite warmer chilled water supply temperatures approaching (sometimes exceeding) 50 degrees F. The ability to meet acceptable discharge air dew points with warmer chilled water supply temperatures improves both operational efficiency and system resilience against chilled water plant operational or control issues. This report summarizes the 59 steady-state test results that form a comprehensive performance map of the HEDS technology including its reheat capability. The breadth of outdoor air conditions and flow rates over which the HEDS technology was tested and characterized encompasses the unit 1) operating as a dedicated outdoor air system or mixed air system and 2) controlled with constant air volume or variable air volume fan control.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2025

ComStock Measure Scenario Documentation: Laboratory-Informed Modeling of Standard Performance Heat Pump Rooftop Units

This measure scenario replaces gas and electric resistance RTUs in the U.S. commercial building stock with standard efficiency commercial off the shelf heat pump rooftop units. This study uses performance data informed by NREL laboratory testing of a standard efficiency 7.5-ton heat pump RTU. This is the key distinction between this measure scenario and a similar ComStock measure scenario - Standard Performance Heat Pump Rooftop Units - that uses published manufacturer data tables to inform performance. These two scenarios are compared in this report.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Estimating Vadose Zone Flow Properties at the 100 K-East Soil Flushing Site Using ERT Monitoring Data: 2023 Interim Report - 100 KE Soil Property Estimation

In situ soil flushing is being using at the Hanford 100 K-East (100 KE) area to transport mobile chromium contamination in the vadose zone to the water table, where it can be collected and treat through pump and treat operations. The efficacy of soil flushing is directly related to the volume of clean water that infiltrates through contaminated soils. In practice, it is infeasible to comprehensively monitor which regions of the vadose zone are being infiltrated through direct sampling of pore water. Consequently, there can be significant uncertainty about which regions of the subsurface have been treated, especially if hydrogeologic conditions are favorable for the development of unstable flows and preferred flow pathways through the vadose zone (Jarvis, Koestel, and Larsbo 2016). Current approaches for quantitative monitoring of soil flushing performance rely on contaminant concentration measurements collected from extractions wells. There is no quantitative information on the volume of flush water delivered to targeted regions of the vadose zone at the Hanford Site, leading to significant uncertainty regarding source term removal and long-term impacts to groundwater. If the subsurface hydrogeologic properties at the 100 KE Area were adequately known, qualitative metrics of soil flushing performance could be simulated, thereby negating expenses required to obtain quantitative performance information through borehole drilling/sampling. However, estimating in situ hydrogeologic properties has long proven elusive, due primarily to a lack of sufficient information to constrain heterogeneous property estimates to a useful degree of certainty. Estimating vadose zone hydrogeologic properties is particularly challenging due the dependence of hydraulic conductivity on saturation. This report describes progress toward a first-of-its-kind demonstration using surface time-lapse 3D electrical resistivity tomography (ERT) monitoring data to estimate the hydrogeologic properties that control flush water transport at the 100 KE soil flushing site. The ultimate objective is (1) to verify sufficient information exists in the ERT monitoring data to adequately resolve vadose zone hydraulic properties, and (2) generate a “digital twin” (i.e., a numerical simulator) that can be used to simulate the amount of flush water that has been delivered to each targeted region of the vadose zone, and thereby assess the efficacy of flush water delivery. Resulting performance estimates can be used in leu of comprehensive borehole drilling and direct sampling (or wellbore logging) that would otherwise be required to obtain the same information.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2026

Quench Propagation On Rare-Earth Barium Copper Oxide (REBCO) Tape

Rare Earth Barium Copper Oxide (REBCO) is a high‑temperature superconducting material that has zero electrical resistance. A quench occurs when a section of the superconductor suddenly transitions to a resistive state after exceeding its critical current. This localized loss of superconductivity generates a voltage rise, serving as an essential signal for quench detection and protection. While capable of carrying extremely high currents, REBCO is mechanically brittle and have slow quench propagation which makes voltage change difficult to detect.

Ju, Han [Northwestern U.]↗
DOE OSTI2026

Modeling the PV System Level Economic Impact of PV Connector Failure Modes

Photovoltaic (PV) connectors must maintain mechanical integrity for over 25 years while operating under UV exposure, elevated temperature, and mechanical loading. Connector degradation increases with electrical resistance, leading to energy losses, unplanned downtime, and higher operation and maintenance (O&M) costs and in severe cases, safety risks from overhearing or arcing. Connector related failures remain among the most frequent causes of disruption in utility-scale PV (UPV) systems, yet their lifetime economic impacts are poorly quantified. This work presents a techno-economic analysis (TEA) framework that links identified connector failure modes to system level energy losses and lifetime cost impacts using identified resistance measurements and failure rates from 6,2761 PV connectors inspected. Connector failures increase system level O&M costs, raising LCOE by roughly 5%. Downtime driven availability losses dominate economic impact. Resistance-driven I2R and IV-curve losses are secondary, but remain non-negligible. Thermal damage, bend-radius violations, and loose connections drive the majority of LCOE uplift Improving connector reliability through better installation quality, inspection, and design can meaningfully reduce lost energy, O&M costs, and LCOE.

14 SOLAR ENERGY↗
DOE OSTI2026

Quench Propagation On Rare-Earth Barium Copper Oxide (REBCO) Tape

Rare-earth barium copper oxide (REBCO) high-temperature superconductors can carry high currents with zero electrical resistance, enabling applications in high-field magnets, energy systems, and fusion devices. However, localized losses of superconductivity, known as quenches, pose a severe risk due to REBCO’s mechanical brittleness and slow quench propagation, complicating early detection. This work investigates quench propagation and thermal response through controlled experiments. A segmented REBCO tape soldered onto a printed circuit board (PCB) with multiple voltage taps and temperature sensors was submerged in liquid nitrogen at 77 K. In the first test, current ramping produced a quench near 360 A, consistent with theoretical current limits, but resulted in local burnout. In the second test, a heater-induced quench at 300 A propagated bidirectionally with velocities ranging from 164–226 mm/s. These results provide critical parameters for improving REBCO quench detection and protection system design while accounting for REBCO’s limited bendability.

Ju, Han [Northern Illinois U.]↗
DOE OSTI2026

Quench Propagation on Rare-Earth Barium Copper Oxide (REBCO) Tape

Rare-earth barium copper oxide (REBCO) high-temperature superconductors can carry high currents with zero electrical resistance, enabling applications in high-field magnets, energy systems, and fusion devices. However, the localized losses of superconductivity called a quench pose a severe risk due to REBCO’s mechanical brittleness and slow quench propagation, hence complicating early detection. This work investigates quench propagation and thermal response through controlled experiments. A segmented REBCO tape soldered on a PCB with multiple voltage taps and temperature sensors was submerged in liquid nitrogen at 77 K. In the first test, current ramping produced a quench near 360 A, consistent with theoretical current limits but resulted in a local burn. In the second test, a heater-induced quench at 300 A propagated bidirectionally with measured velocities ranging from 164–226 mm/s. These measurements provide critical parameters for improving REBCO quench detection and protection system design with accounts for REBCO's limited bendability.

Ju, Han [NIU, DeKalb]↗
DOE OSTI2022

3D hydrogeophysical characterization of managed aquifer recharge basins

Aquifers are increasingly stressed. Managed aquifer recharge provides a potential solution to mitigate this stress and provide sustainable groundwater resources. Subsurface properties are known to have a strong control on the infiltration rates that can be achieved. However, these properties are often highly heterogeneous and difficult to assess with conventional probing techniques. Here, we show the application of 3D geophysical imaging to assess the recharge potential and its variation across several basins used for managed aquifer recharge. We link in-situ measurements of saturated hydraulic conductivity with the electrical resistivity of the subsurface to establish petrophysical relationships and use those relationships to estimate the distribution of hydraulic conductivity throughout the five recharge basins. Our results show a considerable variability in the hydraulic properties, i.e., soil texture and saturated hydraulic conductivity, that have a direct impact on potential infiltration rates. We use the 3D hydraulic property distributions to model groundwater recharge and provide estimates for infiltration rates and volumes, and use this approach to assess the impact of management activities on groundwater recharge performance. Having such data not only enables us to predict infiltration rates, but also provides means for optimizing such water infrastructure.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Electronic Tuning in URu2Si2 Through Ru to Pt Chemical Substitution

Studies that control the unit cell volume and electronic composition have been useful in revealing what factors lead to hidden order and superconductivity in the strongly correlated electron system URu 2 Si 2 . For example, isoelectronic tuning that increases the hybridization between the f and conduction electron states (i.e., applied pressure and Ru → Fe/Os chemical substitution) 1) converts hidden order into antiferromagnetism and 2) destroys the superconductivity. The impact of nonisoelectronic chemical substitution has been less clear, but several unifying trends have recently emerged for chemical substitution vectors that qualitatively add electrons (e.g., Ru → Rh/Ir and Si → P). This includes 1) the rapid destruction of hidden order and superconductivity, 2) composition regions where the underlying Kondo lattice is preserved but does not harbor an ordered state, and 3) the emergence of complex magnetism at large substitutions. In order to assess the limits of this perspective, we have investigated the series U(Ru 1− x Pt x ) 2 Si 2 for x ≲ 0.19, where the Ru and Pt d -shells differ substantially from each other. Magnetic susceptibility, electrical resistivity, and heat capacity measurements unexpectedly reveal a phase diagram with notable similarities to those of other electron doping series. This result reinforces the viewpoint that there is a quasi-universal affect that results from electron doping in this material, and we anticipate that an understanding of these trends will be useful to isolate what factors are foundational for hidden order and superconductivity.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Low-Temperature Annealing of Nanoscale Defects in Polycrystalline Graphite

Polycrystalline graphite contains multi-scale defects, which are difficult to anneal thermally because of the extremely high temperatures involved in the manufacturing process. In this study, we demonstrate annealing of nuclear graphite NBG-18 at temperatures below 28 °C, exploiting the electron wind force, a non-thermal stimulus. High current density pulses were passed through the specimens with a very low-duty cycle so that the electron momentum could mobilize the defects without heating the specimen. The effectiveness of this technique is presented with a significant decrease in electrical resistivity, defect counts from X-ray computed tomography, Raman spectroscopy, and nanoindentation-based mechanical characterization. Such multi-modal evidence highlights the feasibility of nanoscale defect control at temperatures about two orders of magnitude below the graphitization temperature.

Liu, Gongyuan↗
DOE OSTI2022

Integration of Electromagnetic Geophysics Forward Simulation in Coupled Flow and Geomechanics for Monitoring a Gas Hydrate Deposit Located in the Ulleung Basin, East Sea, Korea

We investigate the feasibility of electromagnetic (EM) geophysics methods to detect the dissociation of gas hydrate specifically from a gas hydrate deposit located in the Ulleung Basin, East Sea, Korea via an integrated flow-geomechanics-EM geophysics simulation. To this end, coupled flow and geomechanics simulation is first performed with the multiple porosity model employed, where a mixed formulation with the finite volume (FV) and finite element (FE) methods are taken for the flow and geomechanics, respectively. From the saturation and porosity fields obtained from the coupled flow and geomechanics, the electrical conductivity model is established for the EM simulation. Solving the partial differential equation of electrical diffusion which is linearized using the 3D finite element method (FEM), the EM fields are then computed. For numerical experiments, particularly two approaches in the configuration for the EM methods are compared in this contribution: the surface-to-surface and the surface-to-borehole methods. When the surface-to-surface EM method is employed, the EM is found to be less sensitive, implying low detectability. Especially for the short term of production, the low detectability is attributed to the similarity of electrical resistivity between the dissociated gas (CH4) and hydrate as well as the specific dissociation pattern within the intercalated composites of the field. On the other hand, when the surface-to-borehole EM method is employed, its sensitivity to capture the produced gas flow is improved, confirming its detectability in monitoring gas flow. Hence, the EM geophysics simulation integrated with coupled flow and geomechanics can be a potential tool for monitoring gas hydrate deposits.

depressurization↗
DOE OSTI2025

Total Recycling of Copper Cable Scrap and Production of Carbon Using Fast Microwave Technology

The recycling of cable scrap, particularly from discarded electrical wiring, is gaining significant attention due to the rising demand for copper and the need for sustainable management of electronic waste. Traditionally, mechanical and thermal processings have been used to recover copper and plastic from cables. However, these approaches are often energy-intensive, time-consuming, and costly in terms of equipment and labor. In this study, we present a simple and effective method for recovering materials from cable scrap using a domestic microwave oven. Cable pieces (2–2.5 cm long) were exposed to 700 W of microwave irradiation under rotation for 30 s, enabling the rapid and efficient separation of high-quality copper metal from the core wire, and activated carbon from the carbonized plastic sheath. Microwaves facilitate this process through Ohmic heating, which induces electrical resistance in the metal, generating heat that mechanically loosens the metal and carbonized plastic components. The process demonstrates high efficiency, achieving an 80% reduction in energy consumption compared to conventional processings. This fast and energy-efficient method shows strong potential for scaling up to industrial recycling, offering a cost-effective and environmentally friendly way to recover high-quality materials for further use or repurposing.

Bourlinos, Athanasios B. (ORCID:0000000256165993)↗
DOE OSTI2021

Size-Dependent Electrical Transport Properties in Conducting Diamond Nanostripes

With the advances in nanofabrication technology, horizontally aligned and well-defined nitrogen-doped ultrananocrystalline diamond nanostripes can be fabricated with widths in the order of tens of nanometers. The study of the size-dependent electron transport properties of these nanostructures is crucial to novel electronic and electrochemical applications. In this paper, 100 nm thick n-type ultrananocrystalline diamond thin films were synthesized by microwave plasma-enhanced chemical vapor deposition method with 5% N2 gas in the plasma during the growth process. Then the nanostripes were fabricated using standard electron beam lithography and reactive ion etching techniques. The electrical transport properties of the free-standing single nanostripes of different widths from 75 to 150 nm and lengths from 1 to 128 μm were investigated. The study showed that the electrical resistivity of the n-type ultrananocrystalline diamond nanostripes increased dramatically with the decrease in the nanostripe width. The nanostripe resistivity was nearly doubted when the width was reduced from 150 nm to 75 nm. The size-dependent variability in conductivity could originate from the imposed diffusive scattering of the nanostripe surfaces which had a further compounding effect to reinforce the grain boundary scattering.

Zhou, Andrew F. (ORCID:0000000243050409)↗
DOE OSTI2020

High Speed, Localized Multi-Point Strain Measurements on a Containment Vessel at 1.7 MHz Using Swept-Wavelength Laser-Interrogated Fiber Bragg Gratings

Dynamic elastic strain in ~1.8 and 1.0 m diameter containment vessels containing a high explosive detonation was measured using an array of fiber Bragg gratings. The all-optical method, called real-time localized strain measurement, recorded the strain for 10 ms after detonation with additional measurements being sequentially made at a rate of 1.7 MHz. A swept wavelength laser source provided the repetition rate necessary for such high-speed measurements while also providing enough signal strength and bandwidth to simultaneously measure 8 or more unique points on the vessel’s surface. The data presented here arethen compared with additional diagnostics consisting of a fast spectral interferometer and an optical backscatter reflectometer to show a comparison between the local and global changes in the vessel strain, both dynamically and statically to further characterize the performance of the localized strain measurement. The results are also compared with electrical resistive strain gauges and finite element analysis simulations.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Investigating the Electromechanical Sensitivity of Carbon-Nanotube-Coated Microfibers

The piezoresistance of carbon nanotube (CNT)-coated microfibers is examined using diametric compression. Diverse CNT forest morphologies were studied by changing the CNT length, diameter, and areal density via synthesis time and fiber surface treatment prior to CNT synthesis. Large-diameter (30–60 nm) and relatively low-density CNTs were synthesized on as-received glass fibers. Small-diameter (5–30 nm) and-high density CNTs were synthesized on glass fibers coated with 10 nm of alumina. The CNT length was controlled by adjusting synthesis time. Electromechanical compression was performed by measuring the electrical resistance in the axial direction during diametric compression. Gauge factors exceeding three were measured for small-diameter (<25 μm) coated fibers, corresponding to as much as 35% resistance change per micrometer of compression. The gauge factor for high-density, small-diameter CNT forests was generally greater than those for low-density, large-diameter forests. A finite element simulation shows that the piezoresistive response originates from both the contact resistance and intrinsic resistance of the forest itself. The change in contact and intrinsic resistance are balanced for relatively short CNT forests, while the response is dominated by CNT electrode contact resistance for taller CNT forests. These results are expected to guide the design of piezoresistive flow and tactile sensors.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Real-Time Nitrate Ion Monitoring with Poly(3,4-ethylenedioxythiophene) (PEDOT) Materials

Nitrate (NO 3 ) pollution in groundwater, caused by various factors both natural and synthetic, contributes to the decline of human health and well-being. Current techniques used for nitrate detection include spectroscopic, electrochemical, chromatography, and capillary electrophoresis. It is highly desired to develop a simple cost-effective alternative to these complex methods for nitrate detection. Therefore, a real-time poly (3,4-ethylenedioxythiophene) (PEDOT)-based sensor for nitrate ion detection via electrical property change is introduced in this study. Vapor phase polymerization (VPP) is used to create a polymer thin film. Variations in specific parameters during the process are tested and compared to develop new insights into PEDOT sensitivity towards nitrate ions. Through this study, the optimal fabrication parameters that produce a sensor with the highest sensitivity toward nitrate ions are determined. With the optimized parameters, the electrical resistance response of the sensor to 1000 ppm nitrate solution is 41.79%. Furthermore, the sensors can detect nitrate ranging from 1 ppm to 1000 ppm. The proposed sensor demonstrates excellent potential to detect the overabundance of nitrate ions in aqueous solutions in real time.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

A Field Study of Nonintrusive Load Monitoring Devices and Implications for Load Disaggregation

Evaluations of nonintrusive load monitoring (NILM) algorithms and technologies have mostly occurred in constrained, artificial environments. However, few field evaluations of NILM products have taken place in actual buildings under normal operating conditions. This paper describes a field evaluation of a state-of-the-art NILM product, tested in eight homes. The match rate metric—a technique recommended by a technical advisory group—was used to measure the NILM’s success in identifying specific loads and the accuracy of the energy consumption estimates. A performance assessment protocol was also developed to address common issues with NILM mislabeling and ground-truth comparisons that have not been sufficiently addressed in past evaluations. The NILM product’s estimates were compared to the submetered consumption of eight major appliances. Overall, the product had good performance in disaggregating the energy consumption of the electric water heaters, which included both electric resistance and heat-pump water heaters, but only a fair accuracy with refrigerators, dryers, and air conditioners. The performance was poor for cooking equipment, furnace fans, clothes washers, and dishwashers. Moreover, the product was often unable to detect major loads in homes. Typically, two or more appliances were not detected in a home. At least two dryers, furnace fans, and air conditioners went undetected across the eight homes. On the other hand, the dishwasher was detected in all homes where available or monitored. The key findings were qualitatively compared to those of past field evaluations. Potential areas for improvement in NILM product performance were determined along with areas where complementary technologies may be able to aid in load-disaggregation applications.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Electrical and Magnetic Properties of FeGa 3 with Antisite Disorder

We investigated the electronic and magnetic ground states of the cage compound FeGa 3 under the presence of Fe antisite disorder (namely as Fe 0.258 Ga 0.742 ) by x-ray diffraction (XRD), Mössbauer spectroscopy (MS), magnetization and electrical resistivity. Our results show that approximately 4.5 (5)% Fe antisite occupying one of the two non-equivalent Ga sites changes significantly the electronic and magnetic ground states of the pristine compound. We uncover that Fe 0.258 Ga 0.742 undergoes two magnetic transitions, T 1 ≈ 60 K and T 2 ≈ 15 K, the latter associated with the suppression of semiconducting behavior. We focus our discussion on the role that in-gap impurity states and spin disorder play across semiconducting-metal and paramagnetic-magnetic transitions.

36 MATERIALS SCIENCE↗