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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Integrated and Optimized Energy-Efficient Construction Package for a Community of Production Homes in the Mixed-Humid Climate

Selection and integration of high performance home features are two sides of the same coin in energy efficient sustainable construction. Many advanced technologies are available for selection, but it is in the integration of these technologies into an affordable set of features that can be used on a production basis by builders, that ensures whole-house performance meets expectations. This research high performance home analyzes how a set of advanced technologies can be integrated into a durable and energy efficient house in the mixed-humid climate while remaining affordable to homeowners. The technical solutions documented in this report are the cornerstone of the builder's entire business model based on delivering high-performance homes on a production basis as a standard product offering to all price segments of the residential market. Home Innovation Research Labs partnered with production builder Nexus EnergyHomes (CZ 4). The builder plans to adopt the successful components of the energy solution package for all 55 homes in the community. The research objective was to optimize the builder's energy solution package based on energy performance and construction costs. All of the major construction features, including envelope upgrades, space conditioning system, hot water system, and solar electric system were analyzed. The information in this report can be used by builders and designers to evaluate options, and the integration of options, for increasing the efficiency of home designs in climate zone 4. The data also provide a point of reference for evaluating estimates of energy savings and costs for specific features.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Effects of Humidity on Solid Oxide Fuel Cell Cathodes

This report summarizes results from experimental studies performed by a team of researchers assembled on behalf of the Solid-state Energy Conversion Alliance (SECA) Core Technology Program. Team participants employed a variety of techniques to evaluate and mitigate the effects of humidity in solid oxide fuel cell (SOFC) cathode air streams on cathode chemistry, microstructure, and electrochemical performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Variable Speed Heat Pump Sizing Guide for Mixed-Humid Climates

The similarities and differences between different capacity units in a model family will vary depending on the manufacturer. These unit specific details are critical to choosing the VSHP capacity that will yield the highest energy savings without compromising comfort. In addition, the house construction, climate, and occupant behavior will influence the balance of the heating and cooling load on the house as well as the sensible and latent cooling demand. All of these factors need to be considered when trying to select the proper unit for the highest energy savings. Based on the simulations performed in this study, it is likely that VSHPs with an enhanced dehumidification mode can be sized up to two times the cooling load of the house without any reduction in comfort when compared to a single speed heat pump assuming a typical home and occupant behavior in the mixed-humid and cold climates.

42 ENGINEERING↗
DOE OSTI2013

Efficient Multifamily Homes in a Hot Humid Climate by Atlantic Housing Partners

With assistance from the Florida Solar Energy Center (FSEC) and its Building America Partnership for Improved Residential Construction (BA-PIRC), Atlantic Housing Partners (AHP) has implemented a high performance, systems engineered package of measures. This report demonstrates how the initiative achieves Building America (BA) goals of 30%-50% energy savings. Specifically, the goals are documented as being achieved in the new construction multifamily housing sector in the hot humid climate. Results from energy modeling of the high performance package are presented. The role of utility allowance calculations, used as part of the low-income housing tax credit process, to value those energy savings is discussed, as is customer satisfaction with heat pump water heaters.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Short-Term Test Results: Transitional Housing Energy Efficiency Retrofit in the Hot Humid Climate

This project evaluates the renovation of a 5,800 ft2, multi-use facility located in St. Petersburg, on the west coast of central Florida, in the hot humid climate. An optimal package of retrofit measures was designed to deliver 30%-40% annual energy cost savings for this building with annual utility bills exceeding $16,000 and high base load consumption. Researchers projected energy cost savings for potential retrofit measures based on pre-retrofit findings and disaggregated, weather normalized utility bills as a basis for simulation true-up. A cost-benefit analysis was conducted for the seven retrofit measures implemented; adding attic insulation and sealing soffits, tinting windows, improving whole building air-tightness, upgrading heating and cooling systems and retrofitting the air distribution system, replacing water heating systems, retrofitting lighting, and replacing laundry equipment. The projected energy cost savings for the full retrofit package based on a post-retrofit audit is 35%. The building's architectural characteristics, vintage, and residential and commercial uses presented challenges for both economic projections and retrofit measure construction.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Integrated and Optimized Energy-Efficient Construction Package for a Community of Production Homes in the Mixed-Humid Climate

This research high performance home analyzes how a set of advanced technologies can be integrated into a durable and energy-efficient house in the mixed-humid climate while remaining affordable to homeowners. The technical solutions documented in this report are the cornerstone of the builder's entire business model based on delivering high-performance homes on a production basis as a standard product offering to all price segments of the residential market. Home Innovation Research Labs partnered with production builder Nexus EnergyHomes (CZ 4) and they plan to adopt the successful components of the energy solution package for all 55 homes in the community. The research objective was to optimize the builder's energy solution package based on energy performance and construction costs. All of the major construction features, including envelope upgrades, space conditioning system, hot water system, and solar electric system were analyzed.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Performance Verification of Production-Scalable Energy-Efficient Solutions: Winchester/Camberley Homes Mixed-Humid Climate

Winchester/Camberley Homes collaborated with the Building America team Partnership for Home Innovation to develop a new set of high performance home designs that could be applicable on a production scale. The new home designs are to be constructed in the mixed humid climate zone and could eventually apply to all of the builder's home designs to meet or exceed future energy codes or performance-based programs. However, the builder recognized that the combination of new wall framing designs and materials, higher levels of insulation in the wall cavity, and more detailed air sealing to achieve lower infiltration rates changes the moisture characteristics of the wall system. In order to ensure long term durability and repeatable successful implementation with few call-backs, the project team demonstrated through measured data that the wall system functions as a dynamic system, responding to changing interior and outdoor environmental conditions within recognized limits of the materials that make up the wall system. A similar investigation was made with respect to the complete redesign of the HVAC systems to significantly improve efficiency while maintaining indoor comfort. Recognizing the need to demonstrate the benefits of these efficiency features, the builder offered a new house model to serve as a test case to develop framing designs, evaluate material selections and installation requirements, changes to work scopes and contractor learning curves, as well as to compare theoretical performance characteristics with measured results.

2x6 walls↗
DOE OSTI2017

County-Level Climate Uncertainty for Risk Assessments: Volume 12 Appendix K - Historical Rel. Humidity.

This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Quantitative form and fit of N95 filtering facepiece respirators are retained after dry and humid heat treatments for coronavirus deactivation

Re-use of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for single use only is becoming common in healthcare facilities due to shortages caused by the COVID19 pandemic. Here we report that mouse hepatitis virus (MHV) initially seeded on FFR filter material is inactivated (6 log reduction as measured by 50% tissue culture infective dose (TCID50)) after dry heating at 75 °C for 30 minutes. We also find that the quantitative fit of FFRs after heat treatment at this temperature, under dry conditions or at 90% relative humidity, is not affected by single or ten heating cycles. Previous studies have reported that the filtration efficiency of FFR filters is not negatively impacted by these heating conditions. These results suggest that thermal inactivation of coronaviruses is a potentially rapid and widely deployable method to re-use N95 FFRs in emergency situations where reusing FFRs is a necessity and broad-spectrum sterilization is unavailable. However, we also found that a heat source that emits radiation (e.g., an exposed heating element) results in rapid qualitative degradation of the FFR. Finally, we discuss differences in the results reported here and other recent studies investing heat as a means to recycle FFRs and suggest that overall wear time and donning/doffing cycles are important factors that need to be considered.

36 MATERIALS SCIENCE↗
DOE OSTI2017

County-Level Climate Uncertainty for Risk Assessments: Volume 13 Appendix L - Forecast Relative Humidity

This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Understanding the temperature and humidity dependence of the SiPM characteristics

A miniature version of the ICAL experiment at the India-based Neutrino Observatory, the mini-ICALis in operation at the IICHEP, Madurai. The commissioning work of a Cosmic Muon Veto detector (CMVD)on top of the mini-ICAL is continued using extruded plastic scintillators with embeddedWLS fibers and the SiPM as a photo-transducer. The CMVD is being built to study thefeasibility of a cosmic muon veto for a shallow-depth neutrino experiment. The SiPM is calibratedusing an ultrafast LED driver andthe same calibration techniques will be used during the data taking period with a simplified LED in thesame readout PCB. An experimental setup wasdesigned to characterise the SiPMs in a temperature controlled environment. The readout electronicsinvolves trans-impedance amplifiers and a voltage followers of combined gain 1.24 mV/$\mu$A and adigital storage oscilloscope for the data collection with a minimal distortion of SiPM signal.Various characteristics of the Hamamatsu SiPM (S13360-2050VE), e.g. signal shape, optically correlatedand uncorrelated noise, recovery time etc were studied as a function of $V_{ov}$, number of photoelectrons,the ambient temperature and the humidity. This paper will cover the details of those results.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

Effect of Leaf Water Potential on Internal Humidity and CO 2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flat surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO 2 , thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO 2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Here, our results indicate that the reduction in vapor pressures of water and CO 2 could enhance plant water use efficiency up to about 10% at a leaf water potential of -2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. Lastly, the omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO 2 concentration based on leaf gas exchange measurements. Manufactures of leaf gas exchange measurement systems should incorporate leaf water potentials in measurement set-ups.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Impact of Humidity and Temperature on the Stability of the Optical Properties and Structure of MAPbI3, MA0.7FA0.3PbI3 and (FAPbI3)0.95(MAPbBr3)0.05 Perovskite Thin Films

In situ real-time spectroscopic ellipsometry (RTSE) measurements have been conducted on MAPbI3, MA0.7FA0.3PbI3, and (FAPbI3)0.95(MAPbBr3)0.05 perovskite thin films when exposed to different levels of relative humidity at given temperatures over time. Analysis of RTSE measurements track changes in the complex dielectric function spectra and structure, which indicate variations in stability influenced by the underlying material, preparation method, and perovskite composition. MAPbI3 and MA0.7FA0.3PbI3 films deposited on commercial fluorine-doped tin oxide coated glass are more stable than corresponding films deposited on soda lime glass directly. (FAPbI3)0.95(MAPbBr3)0.05 films on soda lime glass showed improved stability over the other compositions regardless of the substrate, and this is attributed to the preparation method as well as the final composition.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Soil Oxygen Limits Microbial Phosphorus Utilization in Humid Tropical Forest Soils

Soil phosphorus (P) availability is of special interest in many humid tropical forests, especially those on highly weathered, iron (Fe)- and aluminum (Al)-rich soils where P often limits net primary productivity. Phosphorus cycling is partly dependent on the ability of microbes to compete for P with Fe and Al minerals, which strongly bind P. Soil P availability is also indirectly affected by soil redox conditions due to its effects on microbial activity and reductive dissolution of Fe oxides that may weaken Fe-O-P sorption strength. Here, we explored P sorption, soil Fe (II) concentrations, soil CO2 production, organic and inorganic P pools, and microbial biomass P in tropical soils that typically experience frequent low redox (valley soils), or fluctuating redox conditions (slope soils). Soils from both topographic positions were pre-incubated under oxic or anoxic headspaces and then amended with a mixture of P (as orthophosphate) and carbon (C, as acetate, to maintain microbial activity) and incubated in the dark for 24 h. Phosphorus sorption to the mineral phase occurred on a time scale of seconds to minutes in valley and slope soils, reflecting strong abiotic P sorption capacity. Valley soils were characterized by inherently higher Fe(II) concentrations and lower respiration rates. Under anoxic headspaces, Fe(II) concentrations increased 3-to 5-fold in the both soils. Soil respiration and microbial P utilization declined significantly in both soils under anoxic conditions, regardless of Fe(II) concentrations. Microbial P concentrations were highest when slope soils were incubated under an oxic headspace, despite the high P sorption under these conditions. Our results suggest that microbial P utilization is indirectly limited by low O2 availability and that microbes are able to effectively compete with minerals for P under Fe-oxidizing conditions. These results emphasize the central role of soil microorganisms in regulating P availability, even in the presence of strong abiotic sorption capacity.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Relative humidity-dependent viscosity of secondary organic material from toluene photo-oxidation and possible implications for organic particulate matter over megacities

To improve predictions of air quality, visibility, and climate change, knowledge of the viscosities and diffusion rates within organic particulate matter consisting of secondary organic material (SOM) is required. Most qualitative and quantitative measurements of viscosity and diffusion rates within organic particulate matter have focused on SOM particles generated from biogenic volatile organic compounds (VOCs) such as α -pinene and isoprene. In this study, we quantify the relative humidity (RH)-dependent viscosities at 295±1K of SOM produced by photo-oxidation of toluene, an anthropogenic VOC. The viscosities of toluene-derived SOM were 2 × 10 ₋1 to ~6 ×10 6 Pa s from 30 to 90%RH, and greater than ~2 × 10 8 Pa s (similar to or greater than the viscosity of tar pitch) for RH ≤ 17%. These viscosities correspond to Stokes–Einstein-equivalent diffusion coefficients for large organic molecules of ~2 ×10 ₋15 cm 2 s ₋1 for 30 % RH, and lower than ~3 × 10 ₋17 cm 2 s ₋1 for RH ≤ 17 %. Based on these estimated diffusion coefficients, the mixing time of large organic molecules within 200 nm toluene-derived SOM particles is 0.1–5 h for 30% RH, and higher than ~100 h for RH ≤ 17%. As a starting point for understanding the mixing times of large organic molecules in organic particulate matter over cities, we applied the mixing times determined for toluene-derived SOM particles to the world's top 15 most populous megacities. If the organic particulate matter in these megacities is similar to the toluene-derived SOM in this study, in Istanbul, Tokyo, Shanghai, and São Paulo, mixing times in organic particulate matter during certain periods of the year may be very short, and the particles may be well-mixed. On the other hand, the mixing times of large organic molecules in organic particulate matter in Beijing, Mexico City, Cairo, and Karachi may be long and the particles may not be well-mixed in the afternoon (15:00–17:00 LT) during certain times of the year.

Song, Mijung↗
DOE OSTI2019

Relative humidity effect on the formation of highly oxidized molecules and new particles during monoterpene oxidation

It has been widely observed around the world that the frequency and intensity of new particle formation (NPF) events are reduced during periods of high relative humidity (RH). The current study focuses on how RH affects the formation of highly oxidized molecules (HOMs), which are key components of NPF and initial growth caused by oxidized organics. The ozonolysis of α -pinene, limonene, and Δ 3 -carene, with and without OH scavengers, were carried out under low NO x conditions under a range of RH (from ~3 % to ~92 %) in a temperature-controlled flow tube to generate secondary organic aerosol (SOA). A Scanning Mobility Particle Sizer (SMPS) was used to measure the size distribution of generated particles, and a novel transverse ionization chemical ionization inlet with a high-resolution time-of-fight mass spectrometer detected HOMs. A major finding from this work is that neither the detected HOMs nor their abundance changed significantly with RH, which indicates that the detected HOMs must be formed from water-independent pathways. In fact, the distinguished OH - and O 3 -derived peroxy radicals ( RO 2 ), HOM monomers, and HOM dimers could mostly be explained by the autoxidation of RO 2 followed by bimolecular reactions with other RO 2 or hydroperoxy radicals ( HO 2 ), rather than from a water-influenced pathway like through the formation of a stabilized Criegee intermediate (sCI). However, as RH increased from ~3 % to ~92 %, the total SOA number concentrations decreased by a factor of 2–3 while SOA mass concentrations remained relatively constant. These observations show that, while high RH appears to inhibit NPF as evident by the decreasing number concentration, this reduction is not caused by a decrease in RO 2 -derived HOM formation. Possible explanations for these phenomena were discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

A global model–measurement evaluation of particle light scattering coefficients at elevated relative humidity

The uptake of water by atmospheric aerosols has a pronounced effect on particle light scattering properties, which in turn are strongly dependent on the ambient relative humidity (RH). Earth system models need to account for the aerosol water uptake and its influence on light scattering in order to properly capture the overall radiative effects of aerosols. Here we present a comprehensive model–measurement evaluation of the particle light scattering enhancement factor f(RH), defined as the particle light scattering coefficient at elevated RH (here set to 85 %) divided by its dry value. The comparison uses simulations from 10 Earth system models and a global dataset of surface-based in situ measurements. In general, we find a large diversity in the magnitude of predicted f(RH) amongst the different models, which can not be explained by the site types. Based on our evaluation of sea salt scattering enhancement and simulated organic mass fraction, there is a strong indication that differences in the model parameterizations of hygroscopicity and model chemistry are driving at least some of the observed diversity in simulated f(RH). Additionally, a key point is that defining dry conditions is difficult from an observational point of view and, depending on the aerosol, may influence the measured f(RH). The definition of dry also impacts our model evaluation, because several models exhibit significant water uptake between RH = 0 % and 40 %. The multisite average ratio between model outputs and measurements is 1.64 when RH = 0 % is assumed as the model dry RH and 1.16 when RH = 40 % is the model dry RH value. The overestimation by the models is believed to originate from the hygroscopicity parameterizations at the lower RH range which may not implement all phenomena taking place (i.e., not fully dried particles and hysteresis effects). This will be particularly relevant when a location is dominated by a deliquescent aerosol such as sea salt. Our results emphasize the need to consider the measurement conditions in such comparisons and recognize that measurements referred to as dry may not be dry in model terms. Recommendations for future model–measurement evaluation and model improvements are provided.

54 ENVIRONMENTAL SCIENCES↗