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At least 379 records · Page 21

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DOE OSTI2025

Advances in Desiccant Wheels for Dehumidification, VOC Mitigation, and CO 2 Removal for Energy-Efficient IAQ Management

Humidity control is pivotal to maintain occupant thermal comfort and suppress mold growth in indoor environments. Furthermore, poor indoor air quality (IAQ) due to the presence of volatile organic compounds (VOCs) and high concentrations (>1,000 ppm) of CO 2 can cause health issues and negatively affect cognitive performance. Therefore, providing high-quality indoor air has gained significant attention over the past decade. Conventional cooling coil and filter-based HVAC systems have limited capability to meet the augmented demand for occupant thermal comfort and high indoor air quality. Moreover, modern buildings are increasingly airtight to save energy, and increasing ventilation to mitigate VOC and CO 2 concentration is discouraged. Separate sensible and latent cooling technology using a rotary desiccant wheel presents a promising solution in this respect. Because of the development of desiccant materials with high water vapor, VOC, and CO 2 uptake, desiccant wheels can be used as an integrated technology option for IAQ management. Here, to promote desiccant wheel use for energy-efficient management of IAQ in buildings, this article reviews recent advancements in using desiccant wheels for dehumidification, VOC mitigation, and CO 2 capture from outdoor air. Finally, the article presents the authors’ perspective by summarizing the key research gaps in the field and discussing the future direction of research to address these gaps from two different aspects, namely, suitable adsorbent material development and desiccant wheel design.

CO2 capture↗

DOE OSTI2025

Designing slippery rough surfaces to enhance dropwise condensation of low surface tension fluid

Enhancing low surface tension liquid condensation is critical for achieving high energy efficiency and reducing the size of thermal energy systems. Extensive research has focused on promoting dropwise condensation of these liquids using state-of-the-art coatings on plain surfaces. However, maintaining dropwise condensation with low surface tension fluids is challenging due to rivulet formation, resulting in wetted tails that transition to filmwise condensation at elevated heat fluxes. Here, to address this issue, we uncover the role of surface structures and surface chemistry in the dropwise condensation of low surface tension ethanol on slippery rough surfaces (SRS). High-performance dropwise condensation has been achieved on slippery microchannels grafted with perfluoropolyether. The SRS uniquely facilitates rapid lateral droplet removal, enabling faster directional droplet shedding without rivulet formation. The resulting higher droplet removal frequency on SRS leads to heat transfer coefficients 100 % and 500 % higher than conventional dropwise and filmwise condensation on plain surfaces, respectively. Our findings uncover the pivotal role of rapid droplet removal through slippery microchannels in sustaining dropwise condensation of low surface tension liquids. This study introduces a new paradigm for promoting dropwise condensation using engineered SRS that incorporates surface structure and surface chemistry. The work will provide fundamental design guidelines to design efficient and compact condensers that use costly or flammable low global warming potential refrigerants in future refrigeration systems.

Dropwise condensation↗

DOE OSTI2022

The impacts of charge transfer, localization, and metallicity on hydrogen retention and transport capacity

Solid state hydrides such as early transition metal hydrides are of inestimable importance for the future of hydrogen energy and are actively being investigated for energy conversion and storage applications such as fuel cells, solid-state batteries and neutron moderators. The retention and transport behavior of hydrogen in these hydrides has a huge role on the extended performance of components. While early transition-metal-based compounds exhibit many peculiar properties due to their unique correlated electronic signatures arising from -orbital electrons, the fundamental chemistry and transport behavior of hydrogen in such hydrides is not well understood. In the present work, using density functional theory, a highly intricate bonding feature is revealed through the theoretical investigation of the electronic structure of early transition metal hydrides YH 2 and ZrH 2 . In particular, a pronounced charge transfer from the transition element to H, results in localized electron densities at deep energy levels. The interplay between intrinsic charge transfer, charge localization, and metallicity in YH 2 and ZrH 2 leads to strong chemical bonding between metal and hydrogen atoms and large energy barriers for the migration of hydrogen vacancies. Specifically, hydrogen vacancies are found to be stable in the neutral state due to electron screening effects, accompanied by substantially high migration barriers between 0.8–1.2 eV along different crystallographic directions. In contrast, recent literature shows the migration barrier for charged H vacancies in insulating s-block metal hydrides lie between 0.1–0.4 eV, which is suitable for fast conduction applications. This pivotal electron structure difference exploited between early transition metal hydrides and alkali/alkaline earth metal hydrides determines extended hydrogen retention in these early transition metal hydrides. Finally, this work explains fundamental differences between the electronic structure of s-block and d-block metal hydrides, and its impact on the mobility of hydrogen vacancies.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2024

Investigation of precooling unit design options in hydrogen refueling station for heavy-duty fuel-cell electric vehicles

Precooling gaseous hydrogen fuel to a cold temperature before refueling a heavy-duty (HD) hydrogen fuel cell electric vehicle (HFCEV) is essential to avoid overheating the vehicle tank, as well as achieving a high state of charge (SOC). Because a large volume of hydrogen is dispensed during each fill, the need for a shorter fill time amplifies the need to precool each load for refueling a HFCEV. Thus, the design and operation of a precooling unit (PCU), as well as the associated capital and operating costs, plays a pivotal role in any plans for heavy-duty hydrogen refueling stations. Here, in this paper, we present a thermodynamic and technoeconomic analysis of a PCU in a gaseous hydrogen refueling station (HRS) for HD HFCEVs. By employing Argonne National Laboratory's hydrogen station cost optimization and performance evaluation (H2SCOPE) model, the refueling of 50 kg of hydrogen on-board type IV tank at ambient temperatures of 15–45 °C and varying fill rates is simulated. The required degree of precooling temperature to obtain either 100% or the maximum possible SOC is obtained from the simulation. Additionally, the simulation results demonstrate that the average flow rate of hydrogen is approximately 40% lower than the maximum flow rate during a typical fill; which motivates further evaluation of the instantaneous hydrogen mass flow rate profile and suggests the scope of improving precooling unit design. Accordingly, a hybrid strategy of precooling hydrogen has been proposed to address the cooling load by sizing the refrigeration unit for the average flow rate of hydrogen, while supplementing the above average peak hydrogen flow cooling load through thermal buffering. The combined technique enables the downsizing of the original PCU capacity by 25–40% and demonstrates a potential cost reduction of the PCU by approximately 30%, which translates to an installed cost reduction of ∼$125,000 per dispenser.

25 ENERGY STORAGE↗

DOE OSTI2026

Elucidating hydrogen isotope transport mechanisms in proton-conducting ceramics with trapping effects using TMAP8

Hydrogen isotopes play an central role in many science and engineering applications such as fuel cells, hydrogen production, and fusion energy. For these applications, hydrogen separation and extraction applications are pivotal aspects of hydrogen transports, where proton-conducting ceramics (PCCs) have shown great potential. In this study, we propose a new model for hydrogen isotope transport in PCC materials, BaZr 0.9 Y 0.1 O 2.95 (BZY) in particular, which captures behavior in both dry and wet environments. The model expands previous efforts and considers diffusion, trapping, and surface reactions (i.e., dissociation and recombination). We then validate and calibrate the model using deuterium transport measurements from experiments in both dry and wet environments. This study highlights the key role of trapping, often neglected, on hydrogen isotope transport in BZY and other PCC materials. It also explains how the commonly observed discrepancy between dry and wet behavior can be attributed to more active surface reactions and saturated traps due to the increased hydrogen presence under the wet environment. These results provide insights to optimize PCC manufacturing and usage as a hydrogen separation and extraction technology in various fields, emphasizing that lowering the trapping can reduce hydrogen isotope retention. These modeling and calibration efforts are performed using the tritium migration analysis program, version 8 (TMAP8), an open-source application designed for hydrogen isotope transport.

36 - MATERIALS SCIENCE↗

DOE OSTI2022

Association of Short-term Patient-reported Outcomes With Long-term Oncologic Outcomes in Localized Prostate Cancer Patients Treated With Radiation Therapy and Androgen Deprivation Therapy in a Randomized Controlled Trial

Both oncologic outcomes and patient-reported outcomes are pivotal in prostate cancer (PCa). However, it remains unknown if there is any association between these 2 outcomes. In this secondary analysis of a randomized controlled trial, we investigated the association of short-term changes in patient-reported outcome with long-term event-free survival (EFS) and metastasis-free survival (MFS) in localized PCa.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2024

De-risking fault leakage risk and containment integrity for subsurface storage applications

The subsurface is pivotal in the energy transition, for the sequestration of CO 2 and energy storage. It is crucial to understand to what extent geological faults may form leakage pathways that threaten the containment integrity of these projects. Fault flow behavior has been studied in the context of hydrocarbon development, supported by observations from wells drilled through faults, but such observations are rare in geoenergy projects. Focusing on mechanical behavior as early indicator of potential leakage risks, a probabilistic Coulomb Failure Stress workflow is developed and demonstrated using data from the Decatur CO 2 sequestration project to rank faults based on their containment risk. The analysis emphasizes the importance of fault throw relative to reservoir thickness and pore pressure change in assessing reactivation risks. Integrating this mechanical assessment with geological and dynamic fault analyses contributes to derisking fault containment for geoenergy applications, providing valuable insights for the successful development of subsurface storage projects.

58 GEOSCIENCES↗

DOE OSTI2024

Gap junctions fine-tune ganglion cell signals to equalize response kinetics within a given electrically coupled array

Retinal ganglion cells (RGCs) summate inputs and forward a spike train code to the brain in the form of either maintained spiking (sustained) or a quickly decaying brief spike burst (transient). We report diverse response transience values across the RGC population and, contrary to the conventional transient/sustained scheme, responses with intermediary characteristics are the most abundant. Pharmacological tests showed that besides GABAergic inhibition, gap junction (GJ)–mediated excitation also plays a pivotal role in shaping response transience and thus visual coding. More precisely GJs connecting RGCs to nearby amacrine and RGCs play a defining role in the process. These GJs equalize kinetic features, including the response transience of transient OFF alpha (tOFFα) RGCs across a coupled array. We propose that GJs in other coupled neuron ensembles in the brain are also critical in the harmonization of response kinetics to enhance the population code and suit a corresponding task.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2024

Interplay of pressure and temperature in modulating the magnetic properties of Cr 2 O 3

The spin-lattice interaction is pivotal in tailoring materials properties and is crucial for developing novel spintronic devices. Here, in the current work, we aim to explore the effects of pressure and temperature on the magnetic properties of Cr 2 O 3 to gain insights into its spin-lattice interaction. Through high-pressure neutron diffraction experiments, we observed an enhancement of the magnetic Bragg intensity with increasing pressure and it becomes more pronounced as the temperature increases. Results from first-principles calculations reveal a strengthening of the easy-axis magnetic anisotropy, doubling from 0 to 20 GPa. The exchange parameters, calculated based on this spin orientation, show an enhancement of the dominant magnetic interactions and an increase of magnetic ordering temperature when pressure increases. These findings suggest that the contributions from these two mechanisms are responsible for the observed increase in magnetic Bragg intensity.

Cr2O3↗

DOE OSTI2023

Functional analysis of a conserved site mutation in the DNA end processing enzyme PNKP leading to ataxia with oculomotor apraxia type 4 in humans

Polynucleotide kinase 3'-phosphatase (PNKP), an essential DNA end-processing enzyme in mammals with 3'-phosphatase and 5'-kinase activities, plays a pivotal role in multiple DNA repair pathways. Its functional deficiency has been etiologically linked to various neurological disorders. Recent reports have shown that mutation at a conserved glutamine (Gln) in PNKP leads to late-onset ataxia with oculomotor apraxia type 4 (AOA4) in humans and embryonic lethality in pigs. However, the molecular mechanism underlying such phenotypes remains elusive. Here, we report that the enzymatic activities of the mutant versus WT PNKP are comparable; however, cells expressing mutant PNKP and peripheral blood mononuclear cells (PBMCs) of AOA4 patients showed a significant amount of DNA double-strand break accumulation and consequent activation of the DNA damage response. Further investigation revealed that the nuclear localization of mutant PNKP is severely abrogated, and the mutant proteins remain primarily in the cytoplasm. Western blot analysis of AOA4 patient-derived PBMCs also revealed the presence of mutated PNKP predominantly in the cytoplasm. To understand the molecular determinants, we identified that mutation at a conserved Gln residue impedes the interaction of PNKP with importin alpha but not with importin beta, two highly conserved proteins that mediate the import of proteins from the cytoplasm into the nucleus. Collectively, our data suggest that the absence of PNKP in the nucleus leads to constant activation of the DNA damage response due to persistent accumulation of double-strand breaks in the mutant cells, triggering death of vulnerable brain cells—a potential cause of neurodegeneration in AOA4 patients.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2020

Poly(N-isopropylacrylamide)-grafted gold nanoparticles at the vapor/water interface

Hypothesis: Grafting nanoparticles surfaces with water-soluble polymers modify interparticle interactions that are pivotal for assembling them into ordered phases. By manipulating salt concentrations of gold nanoparticles (AuNPs) that are grafted with poly(N-isopropylacrylamide) (PNIPAM-AuNPs), we hypothesize that various aggregated phases form at the suspension/vapor interface or in the bulk that depend on the molecular weight (MW) of PNIPAM and on salt concentrations. Experiments: AuNPs are grafted with thiolated PNIPAM of molecular weights of 3 or 6 kDa, and grafting is confirmed by dynamic light scattering. Liquid-surfaces X-ray reflectivity and grazing incidence small-angle X-ray scattering are used to determine the density profiles of the suspension/vapor interface and their inplane structure as salt is added to the suspensions. Findings: We observe that surface enrichment is induced by adding NaCl to the suspensions, and that at low salt concentrations, the monoparticle layer formed is dispersed, and above a threshold salt concentration, depending on MW of PNIPAM, the PNIPAM-AuNPs order in a hexagonal structure. We show that the lattice constant of the two-dimensional hexagonal structure varies with salt concentration, and more significantly with MW of PNIPAM.

36 MATERIALS SCIENCE↗

DOE OSTI2025

A “Sweet” Biorefinery: Sugar-derived ionic liquids for the pretreatment of lignocellulosic biomass

Sugar-based ionic liquids (ILs) derived from biomass-based cations (choline, betaine) and sugar-derived anions were developed as sustainable pretreatment solvents to advance the concept of self-reliant biorefinery. Cholinium gluconate ([Ch][GlcA]) enabled streamlined one-pot sorghum pretreatment without the need for pH adjustment or washing, while betainium gluconate ([Bet][GlcA]) achieved higher sugar yields, improving overall process efficiency and economics. Both ILs produced hydrolysates fully compatible with microbial fermentation, demonstrating their potential for efficient, simplified biomass conversion. This work positions sugar-based ILs as powerful platforms that unite sustainable chemistry with integrated bioprocessing, marking a pivotal step toward realizing the self-reliant biorefinery.

Biomass-based ions↗

DOE OSTI2022

Methane foam performance evaluation in water-wet unconsolidated porous media: A systematic experimental investigation at elevated pressure and temperature conditions

In the petroleum industry, enhanced oil recovery (EOR) techniques employ foam extensively to establish conformance control in heterogeneous and fractured reservoirs in order to increase the sweep efficiency. In such applications, foam performance evaluation under complex subsurface conditions is pivotal for the effective and optimized deployment of foam treatment. However, there is a scarcity of hydrocarbon gas foam generation and evaluation studies that examine the relationships between foam performance and the critical foam parameters at high-pressure and high-temperature conditions. Here, this study aims at methodically investigating the effects of several foam parameters on methane foam performance in water-wet proppant packs under harsh operating conditions. This is in relation to the technical needs of hydrocarbon foam injection into hydraulically-induced, propped fractures in unconventional oil reservoirs. To this end, a state-of-the-art experimental foam generation apparatus was designed, fabricated, and commissioned. We performed a large number of foam flow experiments on proppant packs using methane gas and different foaming agents at 3500 psi and 115°C. Anionic and amphoteric surfactants were employed to probe the effect of their ionic nature on foam performance. Foam performance sensitivities to various foam generation parameters and operating conditions, such as surfactant concentration, gas fraction, total injection rate, operating pressure, salinity, and proppant pack length were investigated. To this end, steady-state pressure drops across the proppant packs during foam generation and foam's apparent viscosity were measured to quantify the foam performance of surfactants. The results were then analyzed to determine optimum values of the foam parameters and the interplay between these parameters are discussed here. The systematic results achieved from this work are in agreement with the trends available in the literature and provide new insights into complexities of in situ foam generation in water-wet, unconsolidated porous media at extreme reservoir conditions.

03 NATURAL GAS↗

DOE OSTI2025

Production of anhydrous ƒ-element fluorides through the ionothermal treatment of ƒ-element oxalates

The pivotal role of uranium and plutonium fluorides in the nuclear fuel cycle, particularly in the pyrochemical reduction process, is well recognized. Traditionally, the fluorination of uranium and plutonium materials relies on the use of highly toxic and corrosive gases (e.g., HF (g) , F 2(g) ). Herein, we present an alternative approach using the ionic liquid 1‑butyl‑3-methylimidazolium hexafluorophosphate ([Bmim][PF 6 ] (l) ) and/or hexafluorophosphoric acid (HPF 6(aq) ) as fluorinating agents for the ƒ-element oxalates M$^{III}_{2}$(C 2 O 4 ) 3 ∙ 9H 2 O (s) M$^{III}_{2}$(C 2 O 4 ) 3 ∙ 9H 2 O (s) (M III = Ce, Pu) and M IV (C 2 O 4 ) 2 ∙ 6H 2 O (s) (M IV = Th, U). Our findings demonstrate that [Bmim][PF 6 ] (l) and HPF 6(aq) enable the ionothermal fluorination of ƒ-element oxalates, resulting in the formation of anhydrous CeF 3(s) , ThF 4(s) , and UF 4(s) within 2 hours at 200 °C. This method also facilitates the partial fluorination of plutonium(III) oxalate, yielding a mixture of anhydrous PuF 3(s) and an unidentified phase. Overall, the ionothermal treatment approach offers a safer and more efficient means of producing anhydrous ƒ-element fluorides than conventional methods involving hazardous gases. In addition, we describe the morphology of UF 4(s) materials as a function of production route and demonstrate the presence of morphological signatures that could be used during a nuclear forensic investigation.

Cerium↗

DOE OSTI2025

Thermal performance and energy consumption validation of an occupied local government office building outfitted with ceiling tile phase change materials

Buildings present an opportunity for energy conservation and the modulation of peak energy demand through controlled Heating, Ventilation, and Air Conditioning (HVAC) energy use. The administrative and office building stock in the United States holds potential to achieve energy and demand savings through retrofits such as insulation, weatherization, and thermal energy storage. Specifically, there is a need to validate passive phase change material (PCM) applications in full scale in aging administrative buildings in the US to evaluate the energy benefits. Aim of this study was to conduct a whole building level thermal and energy validation of an operational building and explore an alternative method for evaluating energy efficiency. To accomplish this, the study employed PCMs in the drop ceiling and carry out an energy audit and on-site measurement of HVAC systems' energy demand and consumption. A full-scale EnergyPlus energy model, modeled by the authors, served as a baseline for evaluation. The results show that calibrated model's envelope temperature measures fall within the accepted errors. HVAC energy simulation results also fall within the accepted errors for monthly and hourly pre- and post- PCM retrofit electricity and natural gas data. The novelty of this study is that it employees energy scales per Heating Degree Hour and Cooling Degree Hour, in contrast to the commonly used Heating Degree Days and Cooling Degree Days as reported in the literature to analyze energy savings. These findings underscore the pivotal role of a calibrated model in assessing the efficacy of a singular energy measure, like a PCM-retrofitted ceiling, in an occupied office building.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2021

Manufacturing scalability implications of materials choice in inorganic solid-state batteries

The pursuit of scalable and manufacturable all-solid-state batteries continues to intensify, motivated by the rapidly increasing demand for safe, dense electrical energy storage. Here, we describe the numerous, often conflicting implications of materials choices that have been made in the search for effective mitigations to the interfacial instabilities plaguing solid-state batteries. Specifically, we show that the manufacturing scalability of solid-state batteries can be governed by at least three principal consequences of materials selection: (1) the availability, scaling capacity, and price volatility of the chosen materials’ constituents, (2) the manufacturing processes needed to integrate the chosen materials into full cells, and (3) the cell performance that may be practically achieved with the chosen materials and processes. While each of these factors is, in isolation, a pivotal determinant of manufacturing scalability, we show that consideration and optimization of their collective effects and trade-offs is necessary to more completely chart a scalable pathway to manufacturing.

25 ENERGY STORAGE↗

DOE OSTI2024

Toward sustainable electrochemically mediated separations driven by renewable energy

Environmental pollution, water scarcity, resource shortage, and fossil fuel reliance have all represented threats to a sustainable future. Separation processes play a pivotal role in improving sustainability in fields such as industrial processes, resource recycling, wastewater treatment, and water desalination, among others. Electrochemical systems have gained increased attention as effective separation platforms, not only in performance but also as a potentially energy-efficient approach. However, the reliance on non-renewable energy sources, such as fossil fuels, for electricity generation limits the advancement toward a fully sustainable separation process. Integration of separation processes with eco-friendly renewable energy sources can increase overall sustainability and decrease carbon footprint. Here, in this review, we provide an overview of electrochemical separations and recent efforts to integrate them with renewable energy sources such as heat and solar energy. We discuss electrochemical separations, including electrosorption and electrodialysis, and research to transition these processes to thermoelectrochemical (TEC) and photoelectrochemical (PEC) platforms. Finally, we discuss current challenges and future prospects in direct integration of renewable energy sources with separation processes.

electrochemistry↗

DOE OSTI2021

Evaluating the effect of membrane-ionomer combinations and supporting electrolytes on the performance of cobalt nanoparticle anodes in anion exchange membrane electrolyzers

In low temperature polymer electrolyte membrane electrolyzers, component choices and membrane electrode assembly (MEA) fabrication have pivotal roles in determining cell performance. Here, cobalt anodes were used in combination with different ionomers, membranes, and supporting electrolytes to delineate their effect on MEA performance in anion exchange membrane (AEM) based electrolyzers. Changes to the ionomer type suppress or enhance catalyst redox and were found to alter the resulting exchange current densities and Tafel slopes. Changes in membrane conductivity account for large differences in performance and overpotential losses among the different MEAs, with higher conductivity minimizing ohmic losses. Within supporting electrolytes, lower concentration results in lower conductivity and lower MEA performance; the performance, however, is higher in potassium hydroxide than bicarbonate. These experiments address the influence of individual components and their integration on cell-level performance, to help develop a pathway to an electrolyte free system while providing a foundation for studying electrode composition and component incorporation into MEAs.

25 ENERGY STORAGE↗