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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Evaluation of Air Barriers for Residential Buildings

In this project we aimed to increase the knowledgebase on air barriers for residential buildings. To this end, we evaluated nine air barrier assemblies following a modified version of the ASTM E2357 Standard Test Method from the American Society for Testing and Materials. The assemblies included the eight air barrier types that are readily available in the US, even if some of these are currently mostly used in commercial construction. This decision was made because technologies that are utilized in the commercial sector may be adopted by residential builders in the future. We also followed ASTM Standard E283 to estimate the air leakage rates through flow paths that are typically found in walls before and after these were sealed following typical techniques. Assessed leakage paths included wall to foundation joints, as well as penetrations through air barrier systems due to PVC pipes, steel ducts, electrical outlets and brick ties. In addition to the gathered measurements, this report also includes recommendations and considerations on each of the air barrier types. Findings from this research will contribute to the improvement of construction practices that will help meet airtightness requirements set by building codes and programs that seek to reduce energy consumption in homes.

Air Barrier↗
DOE OSTI2019

Estimating the Energy, Economic, and Durability Benefits of Installing an Air Barrier System in Commercial Buildings

Uncontrolled heat, air, and moisture transfer through the building enclosure has a significant impact on energy usage, comfort, indoor air quality, and building enclosure durability. Air leakage in commercial buildings in the U.S. accounts for about one quad (one quadrillion Btu) of energy annually, costing approximately $10 billion. As the thermal resistance of commercial building enclosures continues to improve, the relative contribution of air leakage to heating and cooling loads is increasing. A wide variety of air barrier technologies and construction practices to reduce the air leakage in buildings are available to the architect and designer. To promote more energy-efficient and durable building enclosure design, advances in easy-to-use tools for determining the impact of air leakage are needed. Oak Ridge National Laboratory (ORNL), the Air Barrier Association of America (ABAA), and the National Institute of Standards and Technology (NIST) partnered to develop an online calculator that estimates the potential energy, cost savings (due to energy use reduction), and moisture transport due to improvements in airtightness. The calculator estimates the energy and cost savings potential based on the pre-and post-retrofit air leakage rates for prototype commercial buildings. The tool does not include the energy and hygrothermal impacts of air intrusion or air that flows into and out of the building enclosure from the same side. This article reports on the development of the Energy Savings and Moisture Transfer Calculator. This online tool aims to fill this void, is based on the best science available, and is easy to use.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2016

Air Leakage Rates in Typical Air Barrier Assemblies

Estimates for 2010 indicate that infiltration in residential buildings was responsible for 2.85 quads of energy (DOE 2014), which is about 3% of the total energy consumed in the US. One of the mechanisms being implemented to reduce this energy penalty is the use of air barriers as part of the building envelope. These technologies decrease airflow through major leakage sites such as oriented strand board (OSB) joints, and gaps around penetrations (e.g., windows, doors, pipes, electrical outlets) as indicated by Hun et al. (2014). However, most air barrier materials do not properly address leakage spots such as wall-to-roof joints and wall-to-foundation joints because these are difficult to seal, and because air barrier manufacturers usually do not provide adequate instructions for these locations. The present study focuses on characterizing typical air leakage sites in wall assemblies with air barrier materials.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Development and Implementation of Air Barrier Systems for New and Existing Buildings

A Cooperative Research and Development Agreement (CRADA) was established between Oak Ridge National Laboratory (ORNL) and the Air Barrier Association of America (ABAA) to assess key aspects that influence the performance of air barrier systems commonly use d in residential and commercial buildings. This collaboration was intended to include laboratory experiments and evaluations in a natural exposure test facility, as well as building envelope retrofits that improved the airtightness of existing buildings. Even though the Department of Energy discontinued funding this work after two years, the gathered results provided insight on the effect of air leakage on energy use and material durability, as well as the contribution of common air leaks to energy consumption. Furthermore, ORNL and ABAA have continued collaborating in other projects such as the development of a free online calculator that estimates energy and cost savings due to improvements in airtightness.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2016

US-China Clean Energy Research Center on Building Energy Efficiency: Materials that Improve the Cost-Effectiveness of Air Barrier Systems

The US–China Clean Energy Research Center (CERC) was launched in 2009 by US Energy Secretary Steven Chu, Chinese Minister of Science and Technology Wan Gang, and Chinese National Energy Agency Administrator Zhang Guobao. This 5-year collaboration emerged from the fact that the United States and China are the world’s largest energy producers, energy consumers, and greenhouse gas emitters, and that their joint effort could have significant positive repercussions worldwide. CERC’s main goal is to develop and deploy clean energy technologies that will help both countries meet energy and climate challenges. Three consortia were established to address the most pressing energy-related research areas: Advanced Coal Technology, Clean Vehicles, and Building Energy Efficiency (BEE). The project discussed in this report was part of the CERC-BEE consortia; its objective was to lower energy use in buildings by developing and evaluating technologies that improve the cost-effectiveness of air barrier systems for building envelopes.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Airtightness of Commercial Building Envelopes: Where are we and where could we go?

Air leakage in commercial buildings accounts for about one quad of energy annually; therefore, efforts have been put in place to decrease this energy penalty. Data from blower door tests indicate that the airtightness of new building envelopes has been improving in certain niches because of requirements set by local governments and the US Army Corps of Engineers (USACE), as well as the availability of air barrier consultants. Advances in air barrier technologies and construction practices have also contributed to these improvements. Even with these promising results, efforts have been slow to revise building codes so that they establish a maximum air leakage rate requirement for new buildings and envelope retrofits. This paper summarizes current techniques used to conduct whole building air leakage tests, where these tests are mandatory, how the air leakage rate of buildings appears to be decreasing, and what stakeholders think about blower door tests. The paper also includes the nationwide source energy and financial savings potential for standalone retail buildings that were calculated using a newly developed simulation tool that more accurately estimates the effect of air leakage on energy use.

Hun, Diana E.↗
DOE OSTI2023

Extending the Air and Moisture Leakage Calculator to add Residential Buildings and Additional Commercial Buildings

The DOE Windows and Building Envelope Research and Development Roadmap for Emerging Technologies shows that in 2010, infiltration was responsible for 4 quads of space conditioning primary energy use in the residential and commercial sectors. The relative contribution of air leakage in building heating and cooling load is increasing with improvement in the thermal resistance of building envelopes. Advanced air barrier technologies and construction practices have been developed to reduce air leakage in buildings. However, limited information on the impact of air barrier technologies on energy consumption and the durability of buildings has hindered their adoption. In the past Oak Ridge National Laboratory (ORNL), the National Institute of Standards and Technology (NIST), Air Barrier Association of America (ABBA), and U.S.-China Clean Energy Research Center for Building Energy Efficiency (CERC-BEE) collaborated to develop an online calculator that estimates the potential energy and cost savings in major U.S., Canadian and Chinese cities from improvement in air tightness in commercial buildings. In 2018–2019, the calculator was expanded to add moisture transfer calculations given that air leakage through the building envelope can have a significant impact on moisture transfer and associated impacts. In this study, the calculator is expanded further by adding data for two additional commercial buildings (strip mall and primary school) and a residential building. The team investigated the impact of airtightness on energy consumption and moisture transfer of the added buildings. The study includes the analysis of air tightness in 52 major cities in the U.S. and 5 cities in Canada.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2026

Breakdown and Discharge Characteristics of High Repetition Frequency Nanosecond Pulsed Air Dielectric Barrier Discharge

This study explores the breakdown characteristics and discharge modes in a parallel plate air dielectric barrier discharge system using repetitive nanosecond pulses, with pulse repetition frequencies (PRFs) from 0.1 to 100 kHz. It examines how pulse parameters—PRF, pulse number and gas pressure—affect the memory effect, leveraging current and voltage measurements, fast imaging and optical emission spectroscopy. The findings show that higher PRFs lead to a reduction in breakdown voltage well below the streamer breakdown threshold. We argue that this effect may be attributed to the cumulative buildup of metastable species and negative ions in the discharge gap which could sustain free electrons in‐between the voltage pulses. Despite observing increased energy deposition with higher PRFs, the impact on filament formation was minimal, highlighting a strong dependence of discharge morphology on the accumulation of plasma‐produced species. This research studies provides valuable insights for controlling discharge regimes in applications such as plasma‐assisted combustion, surface treatment and air treatment by clarifying the interactions between discharge mechanisms at different PRFs and pressures.

42 ENGINEERING↗
DOE OSTI2016

LIQUIDARMOR CM Flashing and Sealant, High Impact Technology Demonstration

Air leakage is responsible for about 1.1 quads of energy or 6% of the total energy used by commercial buildings in the US. Consequently, infiltration and exfiltration are among the largest envelope-related contributors to the heating, ventilation, and air conditioning loads in commercial buildings. New air sealing technologies have recently emerged that aim to improve the performance of air barrier systems by simplifying their installation procedure. LIQUIDARMORTM CM Flashing and Sealant is an example of these new advanced material technologies. This technology is a spray-applied sealant and liquid flashing and can span gaps that are up to ¼ in. wide without a supporting material. ORNL verified the performance of LIQUIDARMORTM CM with field tests and energy simulations from a building in which LIQUIDARMORTM CM was one of components of the air barrier system. The Homeland Security Training Center (HTC) at the College of DuPage in Glen Ellyn, IL, served as the demonstration site. Blower door test results show the average air leakage rate in the demonstration site to be 0.15 cfm/ft2 at 1.57 psf, or 63% lower than the 0.4 cfm at 1.57 psf specified in the 2015 International Energy Conservation Code (IECC). According to simulation results, HTC lowered its annual heating and cooling cost by about $3,000 or 9% compared to a similar building that lacked an air barrier system. This demonstration project serves as an example of the level of building envelope airtightness that can be achieved by using air barrier materials that are properly installed, and illustrates the energy and financial savings that such an airtight envelope could attain.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Energy Savings Impacts of Airtightness in U.S. Commercial Buildings

Air leakage in commercial buildings in the U.S. accounts for about one quad of energy annually. As the thermal resistance of commercial building envelopes continues to improve, the relative contribution of air leakage to heating and cooling loads is increasing. Several manufacturers have developed advance air barrier technologies and construction practices to reduce the air leakage in buildings. To help in the market penetration of these advance technologies, advances in easy to use tools for determining the impact of air leakage are needed. Oak Ridge National Laboratory (ORNL), the Air Barrier Association of America, the National Institute of Standards and Technology, and the US-China Clean Energy Research Center for Building Energy Efficiency partnered to develop an online calculator that estimates the potential energy and cost savings in major US, Canadian, and Chinese cities from improvements in airtightness. The calculator estimates the energy and cost savings potential based on the pre and post retrofit air leakage rates for prototype commercial buildings. This report explores extending these savings to determine the national level energy savings potential based on the weightage of commercial building type in different ASHRAE climate zone locations. The base infiltration rate of 1.07 CFM/ft2 was assumed for these calculations and the savings were calculated for three different air infiltration target rates of 0.4 CFM/ft2, 0.25 CFM/ft2, and 0.06 CFM/ft2. The national source energy savings of 238, 283, and 313 TBtu respectively were estimated for these target air infiltration rates.

Bhandari, Mahabir↗
DOE OSTI2016

Field Testing of an Unvented Roof with Fibrous Insulation, Tiles, and Vapor Diffusion Venting

BSC TO5 Task 2.5 Field Testing of an Un-vented Roof with Fibrous Insulation and Tiles - Winter Park, FL 32789 Field test data available for wood moisture contents, temperature, and relative humidity. Un-vented roofs (aka cathedral-ized attics) are an established presence in Florida residential building markets. These roofs are built with a layer of spray polyurethane foam (SPF) on the underside of the roof deck. Such a roof configuration positions the heating, ventilating, and air-conditioning equipment and ductwork within the conditioned space and improves airtight-ness in practice (by shifting the air barrier from the ceiling to the roofline). However, SPF is more expensive than fibrous insulation. Some builders have also become wary of using SPF because of liability concerns about indoor air quality and off-gassing. Unfortunately, un-vented roofs that use only air-permeable fibrous insulation (cellulose or fiberglass) have been demonstrated to be at risk of moisture issues in climate zone 2A because condensation and moisture accumulation occur at the ridge. This report describes research about a test implementation of an un-vented tile roof assembly in a hot-humid climate (Orlando, Florida; climate zone 2A); the roof was insulated with air-permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous work, the U.S. Department of Energy's Building America research team Building Science Corporation theorized that installation of diffusion vents might allow for the wintertime release of moisture to safe levels. Diffusion vents are open slots at the roof's highest points (the ridge and hips) that are covered with a water-resistant but vapor-open (500+ perm) air barrier membrane. The test home is a two-story slab-on-grade structure (3,600 ft2 ); the roof was insulated with a prototype insulation system (called boxed netting), which allows full depth insulation (i.e., it is not limited by the depth of the truss top chord). As a control comparison, one part of the roof was constructed as a typical un-vented roof (with a self-adhered membrane at the ridge). Ideally, failure would occur in the control roof and the experimental (diffusion vent) roofs would show sufficient drying to avoid failure. No intentional space conditioning was provided in the un-vented attic so worst-case humidity buildup conditions could be observed.

air leakage↗
DOE OSTI2016

Field Testing of an Unvented Roof with Fibrous Insulation, Tiles and Vapor Diffusion Venting

This research is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, FL; Zone 2A), insulated with air permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous unvented roof field work, it was theorized that a 'diffusion vent' (water vapor open, but air barrier 'closed') at the highest points in the roof assembly might allow for the wintertime release of moisture, to safe levels. The 'diffusion vent' is an open slot at the ridge and hips, covered with a water-resistant but vapor open (500+ perm) air barrier membrane. As a control comparison, one portion of the roof was constructed as a typical unvented roof (self-adhered membrane at ridge). The data collected to date indicate that the diffusion vent roof shows greater moisture safety than the conventional, unvented roof design. The unvented roof had extended winter periods of 95-100% RH, and wafer (wood surrogate RH sensor) measurements indicating possible condensation; high moisture levels were concentrated at the roof ridge. In contrast, the diffusion vent roofs had drier conditions, with most peak MCs (sheathing) below 20%. In the spring, as outdoor temperatures warmed, all roofs dried well into the safe range (10% MC or less). Some roof-wall interfaces showed moderately high MCs; this might be due to moisture accumulation at the highest point in the lower attic, and/or shading of the roof by the adjacent second story. Monitoring will be continued at least through spring 2016 (another winter and spring).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Field Testing of an Unvented Roof with Fibrous Insulation, Tiles, and Vapor Diffusion Venting

This research is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, FL; Zone 2A), insulated with air permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous unvented roof field work, it was theorized that a 'diffusion vent' (water vapor open, but air barrier 'closed') at the highest points in the roof assembly might allow for the wintertime release of moisture, to safe levels. The 'diffusion vent' is an open slot at the ridge and hips, covered with a water-resistant but vapor open (500+ perm) air barrier membrane. As a control comparison, one portion of the roof was constructed as a typical unvented roof (self-adhered membrane at ridge). The data collected to date indicate that the diffusion vent roof shows greater moisture safety than the conventional, unvented roof design.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Building America Case Study: Field Testing an Unvented Roof with Fibrous Insulation and Tiles, Orlando, Florida

This research is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, FL; Zone 2A), insulated with air permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous unvented roof field work, it was theorized that a 'diffusion vent' (water vapor open, but air barrier 'closed') at the highest points in the roof assembly might allow for the wintertime release of moisture, to safe levels. The 'diffusion vent' is an open slot at the ridge and hips, covered with a water-resistant but vapor open (500+ perm) air barrier membrane. As a control comparison, one portion of the roof was constructed as a typical unvented roof (self-adhered membrane at ridge). The data collected to date indicate that the diffusion vent roof shows greater moisture safety than the conventional, unvented roof design. The unvented roof had extended winter periods of 95-100% RH, and wafer (wood surrogate RH sensor) measurements indicating possible condensation; high moisture levels were concentrated at the roof ridge. In contrast, the diffusion vent roofs had drier conditions, with most peak MCs (sheathing) below 20%. In the spring, as outdoor temperatures warmed, all roofs dried well into the safe range (10% MC or less). Some roof-wall interfaces showed moderately high MCs; this might be due to moisture accumulation at the highest point in the lower attic, and/or shading of the roof by the adjacent second story. Monitoring will be continued at least through spring 2016 (another winter and spring).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Online Airtightness Calculator for the US, Canada and China

The contribution of air leakage to heating and cooling loads has been increasing as the thermal resistance of building envelopes continues to improve. Easy-to-access data are needed to convince building owners and contractors that enhancing the airtightness of buildings is the next logical step to achieve a high-performance building envelope. To this end, Oak Ridge National Laboratory, the National Institute of Standards and Technology, the Air Barrier Association of America, and the US-China Clean Energy Research Center for Building Energy Efficiency Consortium partnered to develop an online calculator that estimates the potential energy savings in major US, Canadian, and Chinese cities due to improvements in airtightness. This tool will have user-friendly graphical interface that uses a database of CONTAM-EnergyPlus pre-run simulation results, and will be available to the public at no cost. Baseline leakage rates are either user-specified or the user selects them from the supplied typical leakage rates. Users will enter the expected airtightness after the proper installation of an air barrier system. Energy costs are estimated based on the building location and inputs from users. This paper provides an overview of the methodology that is followed in this calculator, as well as results from an example. The successful deployment of this calculator could influence construction practices so that greenhouse gas emissions from the US, Canada, and China are significantly curtailed.

air leakage↗