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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 1,567 records · Page 87
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Moisture performance of sealed attics in the mixed-humid climate

Oak Ridge National Laboratory studied 8 homes in the mixed-humid climate, 4 with vented attics and 4 with sealed attics. ORNL wanted to understand the moisture performance of the sealed attic and how it affected the interior environment. We found that the attic and interior of sealed attic homes were more humid than the attic and interior observed in vented attic homes. This is due to the lack of ventilation in the sealed attic. Historically attics have been vented to dehumidify the attic and interior of the home. A sealed attic design greatly reduces the venting potential and thus this drying pathway and can cause elevated interior moisture over a vented attic home. Despite the elevated attic and interior moisture in the sealed attic homes, so far no mold or material degradation has been found. The roof sheathing moisture content has stayed below 20%, indicating low potential for material degradation. Also the relative humidity at the roof sheathing has stayed within the ASHRAE 160 design criteria except for a short time during the 2011/2012 winter. This was due to a combination of the sealed attic design (minimal venting to the outside) and the duct work not being operated in the attic which usually provides a dehumidification pathway. It was also found that when the humidity was controlled using the HVAC system, it resulted in 7% more cooling energy consumption. In the mixed-humid climate this reduces the cost effectiveness of the sealed attic design as a solution for bringing ducts into a semi-conditioned space. Because of this we are recommending the other alternatives be used to bringing ducts into the conditioned space in both new construction and retrofit work in the mixed-humid climate.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Insulated Concrete Form Walls Integrated With Mechanical Systems in a Cold Climate Test House

Transitioning from standard light frame to a thermal mass wall system in a high performance home will require a higher level of design integration with the mechanical systems. The much higher mass in the ICF wall influences heat transfer through the wall and affects how the heating and cooling system responds to changing outdoor conditions. This is even more important for efficient, low-load homes with efficient heat pump systems in colder climates where the heating and cooling peak loads are significantly different from standard construction. This report analyzes a range of design features and component performance estimates in an effort to select practical, cost-effective solutions for high performance homes in a cold climate. Of primary interest is the influence of the ICF walls on developing an effective air sealing strategy and selecting an appropriate heating and cooling equipment type and capacity. The domestic water heating system is analyzed for costs and savings to investigate options for higher efficiency electric water heating. A method to ensure mechanical ventilation air flows is examined. The final solution package includes high-R mass walls, very low infiltration rates, multi-stage heat pump heating, solar thermal domestic hot water system, and energy recovery ventilation. This solution package can be used for homes to exceed 2012 International Energy Conservation Code requirements throughout all climate zones and achieves the DOE Challenge Home certification.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Measure Guideline: Supplemental Dehumidification in Warm-Humid Climates

This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. In older homes in warm-humid climates, cooling loads are typically high and cooling equipment runs a lot to cool the air. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisture being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and some winter days. In warm-humid climates, those long off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and avoids adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

An Assessment of Envelope Measures in Mild Climate Deep Energy Retrofits

Energy end-uses and interior comfort conditions have been monitored in 11 Deep Energy Retrofits (DERs) in a mild marine climate. Two broad categories of DER envelope were identified: first, bringing homes up to current code levels of insulation and airtightness, and second, enhanced retrofits that go beyond these code requirements. The efficacy of envelope measures in DERs was difficult to determine, due to the intermingled effects of enclosure improvements, HVAC system upgrades and changes in interior comfort conditions. While energy reductions in these project homes could not be assigned to specific improvements, the combined effects of changes in enclosure, HVAC system and comfort led to average heating energy reductions of 76percent (12,937 kWh) in the five DERs with pre-retrofit data, or 80percent (5.9 kWh/ft2) when normalized by floor area. Overall, net-site energy reductions averaged 58percent (15,966 kWh; n=5), and DERs with code-style envelopes achieved average net-site energy reductions of 65percent (18,923 kWh; n=4). In some homes, the heating energy reductions were actually larger than the whole house reductions that were achieved, which suggests that substantial additional energy uses were added to the home during the retrofit that offset some heating savings. Heating system operation and energy use was shown to vary inconsistently with outdoor conditions, suggesting that most DERs were not thermostatically controlled and that occupants were engaged in managing the indoor environmental conditions. Indoor temperatures maintained in these DERs were highly variable, and no project home consistently provided conditions within the ASHRAE Standard 55-2010 heating season comfort zone. Thermal comfort and heating system operation had a large impact on performance and were found to depend upon the occupant activities, so DERs should be designed with the occupants needs and patterns of consumption in mind. Beyond-code building envelopes were not found to be strictly necessary for the achievement of deep energy savings in existing uninsulated homes in mild marine climates, provided that other energy end-uses were comprehensively reduced. We recommend that mild climate DERs pursue envelopes in compliance with the 2012 International Energy Conservation Code (IECC) and pair these with high efficiency, off-the-shelf HVAC equipment. Enhanced building envelopes should be considered in cases where very low heating energy use (<1,000 kWh/year or <0.5 kWh/ft2-year) and enhanced thermal comfort (ASHRAE 55-2010) are required, as well as in those situations where substantial energy uses are added to the home, such as decorative lighting, cooling or smart home A/V and communication equipment.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Application of global weather and climate model output to the design and operation of wind-energy systems

This project addressed the challenge of providing weather and climate information to support the operation, management and planning for wind-energy systems. The need for forecast information is extending to longer projection windows with increasing penetration of wind power into the grid and also with diminishing reserve margins to meet peak loads during significant weather events. Maintenance planning and natural gas trading is being influenced increasingly by anticipation of wind generation on timescales of weeks to months. Future scenarios on decadal time scales are needed to support assessment of wind farm siting, government planning, long-term wind purchase agreements and the regulatory environment. The challenge of making wind forecasts on these longer time scales is associated with a wide range of uncertainties in general circulation and regional climate models that make them unsuitable for direct use in the design and planning of wind-energy systems. To address this challenge, CFAN has developed a hybrid statistical/dynamical forecasting scheme for delivering probabilistic forecasts on time scales from one day to seven months using what is arguably the best forecasting system in the world (European Centre for Medium Range Weather Forecasting, ECMWF). The project also provided a framework to assess future wind power through developing scenarios of interannual to decadal climate variability and change. The Phase II research has successfully developed an operational wind power forecasting system for the U.S., which is being extended to Europe and possibly Asia.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Measure Guideline: Supplemental Dehumidification in Warm-Humid Climates

This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. Cooling loads are typically high and cooling equipment runs a lot to cool the air in older homes in warm-humid climates. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisture being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and winter days. In warm-humid climates, those long-off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Energy Savings of Low-E Storm Windows and Panels across US Climate Zones

This report builds off of previous modeling work related to low-e storm windows used to create a "Database of U.S. Climate-Based Analysis for Low-E Storm Windows." This work updates similar studies using new fuel costs and examining the separate contributions of reduced air leakage and reduced coefficients of overall heat transfer and solar heat gain. In this report we examine the energy savings and cost effectiveness of low-E storm windows in residential homes across a broad range of U.S. climates, excluding the impact from infiltration reductions, which tend to vary using the National Energy Audit Tool (NEAT) and RESFEN model calculations. This report includes a summary of the results, NEAT and RESFEN background, methodology, and input assumptions, and an appendix with detailed results and assumptions by climate zone.

energy-efficiency↗
DOE OSTI2016

Collaborative Project. 3D Radiative Transfer Parameterization Over Mountains/Snow for High-Resolution Climate Models. Fast physics and Applications

Under the support of the aforementioned DOE Grant, we have made two fundamental contributions to atmospheric and climate sciences: (1) Develop an efficient 3-D radiative transfer parameterization for application to intense and intricate inhomogeneous mountain/snow regions. (2) Innovate a stochastic parameterization for light absorption by internally mixed black carbon and dust particles in snow grains for understanding and physical insight into snow albedo reduction in climate models. With reference to item (1), we divided solar fluxes reaching mountain surfaces into five components: direct and diffuse fluxes, direct- and diffuse-reflected fluxes, and coupled mountain-mountain flux. “Exact” 3D Monte Carlo photon tracing computations can then be performed for these solar flux components to compare with those calculated from the conventional plane-parallel (PP) radiative transfer program readily available in climate models. Subsequently, Parameterizations of the deviations of 3D from PP results for five flux components are carried out by means of the multiple linear regression analysis associated with topographic information, including elevation, solar incident angle, sky view factor, and terrain configuration factor. We derived five regression equations with high statistical correlations for flux deviations and successfully incorporated this efficient parameterization into WRF model, which was used as the testbed in connection with the Fu-Liou-Gu PP radiation scheme that has been included in the WRF physics package. Incorporating this 3D parameterization program, we conducted simulations of WRF and CCSM4 to understand and evaluate the mountain/snow effect on snow albedo reduction during seasonal transition and the interannual variability for snowmelt, cloud cover, and precipitation over the Western United States presented in the final report. With reference to item (2), we developed in our previous research a geometric-optics surface-wave approach (GOS) for the computation of light absorption and scattering by complex and inhomogeneous particles for application to aggregates and snow grains with external and internal mixing structures. We demonstrated that a small black (BC) particle on the order of 1 μm internally mixed with snow grains could effectively reduce visible snow albedo by as much as 5–10%. Following this work and within the context of DOE support, we have made two key accomplishments presented in the attached final report.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Climate Change Feedbacks from Interactions Between New and Old Carbon

Priming effects, or responses of SOM decomposition rates to inputs of new, labile carbon (C), have the potential to dramatically alter projections of ecosystem C storage. Priming effects occur in most ecosystems, are significant in magnitude, and are highly sensitive to global changes. Nevertheless, our mechanistic understanding of priming effects remains poor, and this has prevented the inclusion of these dynamics into current Earth system models (ESMs). We conducted two manipulative experiments in the field to quantify how priming effects influence SOM dynamics. Specifically, we asked: To what extent do inputs of “new” root-derived carbon (C) influence “older” C in SOM, and are the magnitude and direction of these effects sensitive to climate? We addressed these questions within the Boston-Area Climate Experiment - an old-field ecosystem that has been subjected to three precipitation treatments (ambient, -50%, and +50% of each precipitation event during the growing season) and four warming treatments (from ambient to +4°C) since 2008. In the first experiment, we installed root and fungal ingrowth cores into the plots. Each core was filled with SOM that had an isotopic signature (of its C compounds) that differed from the vegetation in the plots such that inputs of “new” C from roots/fungi could be quantified using the change in isotopic signatures of C in the cores. Further, we used cores with different mesh sizes to isolate root vs. mycorrhizal fungal inputs. We found that belowground C fluxes were dominated by root inputs (as opposed to mycorrhizal inputs), and that root-derived inputs were greatest in the plots subjected to experimental warming. Given that that the warming-induced increase in belowground C flux did not result in a net increase in soil C, we conclude that the warming treatment likely enhanced priming effects in these soils. In the second experiment, we experimentally dripped dissolved organic C compounds into soils in the BACE plots to simulate root-derived C fluxes. Specifically, we constructed artificial roots attached to an automated peristaltic pump to deliver the compounds to soil semi-continuously during the peak of the growing season. We found that changes in exudate quality had small but significant effects on microbial activities, often interacting with N availability and temperature-induced changes. These results further underscore the importance of priming effects, especially under warming conditions. Collectively, our results provide some of the first field-based estimates of how soil moisture and temperature can directly and indirectly alter root-induced changes in SOM dynamics. This exploratory project lays the groundwork for further research on priming that incorporates effects of plant species and microbial communities to global changes. Such information should enable the development of more mechanistic and better predictive models of SOM decomposition under increased greenhouse gas levels, with the ultimate goal of reducing the level of uncertainty in projections of future climate.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Extreme Precipitation and Runoff under Changing Climate in Southern Maine

The quantification of extreme precipitation events is vitally important for designing and engineering water and flood sensitive infrastructure. Since this kind of infrastructure is usually built to last much longer than 10, 50, or even 100 years, there is great need for statistically sound estimates of the intensity of 10-, 50-, 100-, and 500-year rainstorms and associated floods. The recent assessment indicated that the intensity of the most extreme precipitation events (or the heaviest 1% of all daily events) have increased in every region of the contiguous states since the 1950s (Melillo et al. 2014). The maximum change in precipitation intensity of extreme events occurred in the northeast region reaching 71%. The precipitation extremes can be characterized using intensity-duration-frequency analysis (IDF). However, the current IDFs in this region were developed around the assumption that climate condition remains stationary over the next 50 or 100 years. To better characterize the potential flood risk, this project will (1) develop precipitation IDFs on the basis of both historical observations and future climate projections from dynamic downscaling with Argonne National Laboratory’s (Argonne’s) regional climate model and (2) develop runoff IDFs using precipitation IDFs for the Casco Bay Watershed. IDF development also considers non-stationary distribution models and snowmelt effects that are not incorporated in the current IDFs.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Predicting Ice Sheet and Climate Evolution on Extreme Scales (PISCEES) Final Report

Predicting Ice Sheet and Climate Evolution at Extreme Scales (PISCEES) PISCEES is a SciDAC Earth System Modeling project with the following goals: To develop and apply robust, accurate, and scalable dynamical cores for ice sheet modeling on structured and unstructured meshes with adaptive refinements To evaluate ice sheet models using new tools and data sets for verification and validation (V&V) and uncertainty quantification (UQ) To integrate these models and tools into DOE's Accelerated Climate Model for Energy (ACME) using improved estimates of ice sheet initial conditions, we will simulate decade-to-century-scale evolution of the Greenland and Antarctic ice sheets, running PISCEES ice sheet models both in standalone mode and coupled to ACME. We aim to provide useful, credible predictions, including uncertainty ranges, of future ice-sheet mass loss and resulting changes in climate and sea level. PISCEES is jointly funded by the Office of Biological and Environmental Research (BER) and the Office of Advanced Scientific Computing Research (ASCR) of the DOE Office of Science. Participating institutions: Los Alamos National Laboratory (LANL) Lawrence Berkeley National Laboratory (LBNL) Oak Ridge National Laboratory (ORNL) Sandia National Laboratories (SNL) Florida State University (FSU) Massachusetts Institute of Technology (MIT) University of South Carolina (USC) University of Texas at Austin (UT) National Center for Atmospheric Research (NCAR) (https://www.scidac.gov/PISCEES/).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

High-Resolution Coupling and Initialization to Improve Predictability and Predictions in Climate Models Workshop, September 30 – October 2, 2015

The goals of the workshop were 1) to enhance interactions and communications between the climate-prediction and the climate modeling and projection communities, 2) to summarize and synthesize the current status of the research and also document the challenges in initialized high-resolution simulations in both communities, and 3) to identify the criteria for establishing a multi-model experimental framework to optimally address major pressing questions in the context of available computing resources. The two-and-a-half-day workshop was hosted September 30 to October 2, 2015, at the NOAA Center for Weather and Climate Prediction.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Climate and Environmental Sciences Division, North Slope of Alaska Priorities Workshop, September 10–12, 2014

The U.S. Department of Energy (DOE) Climate and Environmental Sciences Division (CESD) within the Office of Biological and Environmental Research (BER), is hosting a series of workshops to solicit community feedback on how key scientific needs, gaps, and priorities in process model understanding and climate model prediction could be addressed through strategic deployment and operation of instruments and routine high resolution modeling. In particular, the use of the Atmospheric Radiation Measurement (ARM) Climate Research Facility—a DOE Office of Science user facility— is being reconfigured to better support the integration of observations and high-resolution modeling and to address these types of emerging science questions. As part of ARM’s reconfiguration, instruments are being concentrated to produce denser observational capabilities at fewer sites. In September 2014, the North Slope of Alaska (NSA) Priorities Workshop was held to obtain scientific input on priorities for observational and scientific research activities related to atmospheric processes in the North Slope region and to identify gaps or needs that limit the ability of the research community to address these scientific priorities. Topics of discussion included capabilities at the existing ARM NSA facilities in Barrow and Oliktok Point, additional observations that may supplement and/or link these facilities (e.g., aircraft, unmanned aerial systems, tethered balloons, scanning radar systems, surface stations), and modeling activities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

New approaches for understanding the statistics of daily weather extremes in a changing climate. SARDESHMUKH_Final_Technical_Report_Extremes_DE-SC0006965

This project quantified the changes in the mean climate and climate variability over the last 140 years, with emphasis on the changes in the tails of the probability distributions of daily variations, i.e. changes in extreme weather statistics. We were interested in not just the mean shifts of the distributions under climate change but also changes in the variance and higher statistical moments such as skewness and kurtosis. The project focused on two important aspects of the probability density functions (pdfs) of daily anomalies and their estimations from observational records of limited length. The first is that the pdfs are not Gaussian but are distinctively skewed and heavy tailed. This has large implications for the probabilities of extreme values and for estimating those probabilities from limited records. It also motivated our second focus, to estimate the pdfs from the longest available global datasets based on instrumental observations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Urban Landscape and Climate Change

A workshop on how earth system models incorporate the influences of urban environments on climate, with an emphasis on how large observation studies can be used to aid the modeling community, was held on August 27 - 28, 2013 at Argonne National Laboratory. The goal of the workshop was to identify urban processes important in influencing the predictive capability of regional climate models and global earth system models, the impacts of climate change that are important for future urban centers, data available or needed to develop a representative model of urban ecosystems, and how cities can use that information to improve the lives of their residents.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Multi-‘omic’ analyses of the dynamics, mechanisms, and pathways for carbon turnover in grassland soil under two climate regimes

Soil microbial activity drives the carbon and nitrogen cycles and is an important determinant of atmospheric trace gas turnover, yet most soils are dominated by microorganisms with unknown metabolic capacities. This knowledge gap precludes meaningful predictions of relationships between microorganism types and their biogeochemical functions. Specifically, as climate change physically alters terrestrial ecosystems, the impact on microbial consortia and potential consequences for release of carbon and other nutrients from soils are difficult to predict. In this project, we investigated the identities, activity, and functional potential of microorganisms residing in a well characterized grassland ecosystem (the Angelo Coast Range Reserve) undergoing a controlled 14-year rainfall extension climate change experiment. The research was achieved using a combination of “omics”-based technologies, including genome-resolved metagenomics, transcriptomics, and proteomics. The approach allowed us to capture multiple facets of community ecology and activity in situ. Supported by this award, significant progress was made in addressing the grand challenge of achieving genome-resolution for very complex soil microbial communities. In addition to improvements in the methodology, the research required new approaches to define the 3-dimentional distributions of microorganisms and their metabolic traits in soils and to decipher the impact of climate. Underpinning such analyses was the need for sufficient statistical power to test for geographic, soil depth and rainfall controls on community composition and metabolic properties. This required that we scale up throughput substantially. We overcame significant technical barriers to achieve complex microbial community resolution.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

ARM Cloud Radar Simulator Package for Global Climate Models

It has been challenging to directly compare U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility ground-based cloud radar measurements with climate model output because of limitations or features of the observing processes and the spatial gap between model and the single-point measurements. To facilitate the use of ARM radar data in numerical models, an ARM cloud radar simulator was developed to converts model data into pseudo-ARM cloud radar observations that mimic the instrument view of a narrow atmospheric column (as compared to a large global climate model [GCM] grid-cell), thus allowing meaningful comparison between model output and ARM cloud observations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Annual Energy Savings and Peak Power Reduction Simulated for CCHP Design and Baseline HP in Cold Climate Cities

This report assesses energy savings and peak power reduction of three heat pumps in multiple US cold climate cities and building types. The three heat pumps comprise a baseline heat pump and two high efficiency cold climate heat pumps (CCHP). The DOE/ORNL Heat Pump Design Model was used to simulate the heat pumps and generate performance curves for EnergyPlus building energy simulations. The annual energy simulations were performed over seven cold climates: 1) Minneapolis, MN; 2) Duluth, MN; 3) Fairbanks, AK; 4) Helena, MT; 5) Indianapolis, IN; 6) Peoria, IL and 7) Eagle County, CO. In order to assess impact of residential building types matching different energy codes, we simulated six single-family houses in Indianapolis, IN, including : 1) single-family house having a crawlspace; 2) having a slab foundation; 3) having a heated basement; 4) having an unheated basement; 5) one single-family house having a heated basement matching IECC code of 2009, 6) and one single-family house having a heated basement matching IECC code of 2012. The former 4 houses match the IECC 2006 code.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗