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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Technology Solutions Case Study: Buried and Encapsulated Ducts, Jacksonville, Florida

Ductwork installed in unconditioned attics can significantly increase the overall heating and cooling costs of residential buildings. In fact, estimated duct thermal losses for single-family residential buildings with ductwork installed in unconditioned attics range from 10% to 45%. In a study of three single-story houses in Florida, the Building America research team Consortium for Advanced Residential Buildings (CARB) investigated the strategy of using buried and/or encapsulated ducts (BED) to reduce duct thermal losses in existing homes. The BED strategy consists of burying ducts in loose-fill insulation and/or encapsulating them in closed cell polyurethane spray foam (ccSPF) insulation; specifically for use in humid climates.

attics↗
DOE OSTI2013

New Whole-House Solutions Case Study: Affordable Cold Climate Infill Housing with Hybrid Insulation Approach, Wyandotte, Michigan

Even builders who are relatively new to energy-efficient construction can consistently reach a target whole house airtightness of 1.5 air changes per hour at 50 Pascals (ACH50) with high R-value enclosures that use a hybrid insulation approach. In 2010, the City of Wyandotte, Michigan, started construction to build affordable, energy-efficient homes on lots in existing neighborhoods. A goal was to engage local builders in energy-efficient construction and be able to deliver the new houses for less than $100/ft2. By the end of 2012, approximately 25 new houses were built by five local builders under this program. To help builders consistently achieve the airtightness target, a local architect worked with researchers from Building Science Corporation, a Building America team, to develop a technology specification with several key pieces. A high R-value wall and roof assembly made use of 2 ×6 advanced framing and a hybrid insulation approach that included insulating sheathing to control thermal bridging and closed cell spray polyurethane foam insulation (ccSPF) for its airtightness and vapor control benefits. This approach allows the air barrier to be completed and tested before any finishing work occurs, ensuring that problems are spotted and corrected early in the construction process.

BSC↗
DOE OSTI2016

Building America Case Study: Compact Buried Ducts in a Hot-Humid Climate House, Lady's Island, South Carolina

A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval. The primary research question with buried ducts is potential condensation at the outer jacket of the duct insulation in humid climates during the cooling season. Current best practices for buried ducts rely on encapsulating the insulated ducts with closed-cell spray polyurethane foam insulation to control condensation and improve air sealing. The encapsulated buried duct concept has been analyzed and shown to be effective in hot-humid climates. The purpose of this project is to develop an alternative buried duct system that performs effectively as ducts in conditioned space - durable, energy efficient, and cost-effective - in a hot-humid climate (IECC warm-humid climate zone 3A) with three goals that distinguish this project: 1) Evaluation of design criteria for buried ducts that use common materials and do not rely on encapsulation using spray foam or disrupt traditional work sequences, 2) Establishing design criteria for compact ducts and incorporate those with the buried duct criteria to further reduce energy losses and control installed costs, and 3) Developing HVAC design guidance for performing accurate heating and cooling load calculations for compact buried ducts.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Technology Solutions for Existing Homes Case Study: Trade-Friendly Retrofit Insulated Panels for Existing Buildings

For this project with the U.S. Department of Energy Building America team Home Innovation Research Labs, the retrofit insulated panels relied on an enhanced expanded polystyrene (EPS) for thermal resistance of R-4.5/inch, which is an improvement of 10% over conventional (white-colored) EPS. EPS, measured by its life cycle, is an alternative to commonly used extruded polystyrene and spray polyurethane foam. It is a closed-cell product made up of 90% air, and it requires about 85% fewer petroleum products for processing than other rigid foams.

building america↗
DOE OSTI2016

Building America Case Study: Optimized Slab-on-Grade Foundation Insulation Retrofits, Madison, Wisconsin

A more accurate assessment of SOG foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated). The optimum insulation strategy was applied to single and multi-family residential buildings in climate zone 4 - 7. The highest site energy savings of 5% was realized for a single family home in Duluth, MN, and the lowest savings of 1.4 percent for a 4-unit townhouse in Richmond, VA. SOG foundation insulation retrofit simple paybacks ranged from 18 to 47 years. There are other benefits of SOG foundation insulation resulting from the increase in the slab surface temperatures. These include increased occupant thermal comfort, and a decrease in slab surface condensation particularly around the slab perimeter.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Sealed Attics Exposed to Two Years of Weathering in a Hot and Humid Climate

Field studies in a hot, humid climate were conducted to investigate the thermal and hygrothermal performance of ventilated attics and non-ventilated semi-conditioned attics sealed with open-cell and with closed-cell spray polyurethane foam insulation. Moisture pin measurements made in the sheathing and absolute humidity sensor data from inside the foam and from the attic air show that moisture is being stored in the foam. The moisture in the foam diffuses to and from the sheathing dependent on the pressure gradient at the foam-sheathing interface which is driven by the irradiance and night-sky radiation. Ventilated attics in the same hot, humid climate showed less moisture movement in the sheathing than those sealed with either open- or closed-cell spray foam. In the ventilated attics the relative humidity drops as the attic air warms; however, the opposite was observed in the sealed attics. Peaks in measured relative humidity in excess of 80 90% and occasionally near saturation (i.e., 100%) were observed from solar noon till about 8 PM on hot, humid days. The conditioned space of the test facility is heated and cooled by an air-to-air heat pump. Therefore the partial pressure of the indoor air during peak irradiance is almost always less than that observed in the sealed attics. Field data will be presented to bring to light the critical humidity control issues in sealed attics exposed to hot, humid climates.

insulation↗
DOE OSTI2018

Measured Thermal and Moisture Performance of an Air Sealed and Insulated Attic with Porous Insulation

Sealed and insulated attic construction can provide substantial HVAC energy savings in homes with space conditioning equipment in the attic. But these assemblies also come with moisture risks, largely due to condensation on cold sheathing surfaces, combined with no mechanism for subsequent moisture removal. Spray polyurethane foam has traditionally been used as both a sealant and insulation material, while also reducing moisture risk. As part of an effort to drastically lower the cost of this construction method, we have instrumented two occupied, test homes in the Fresno region of California’s Central Valley that have sealed and insulated attics using solely unfaced R38 fiberglass batt insulation. Our goals are to assess if the attics can be considered to be within conditioned space, and if moisture problems are apparent using this low-cost building strategy. We found that the sealed and insulated attic can be considered as conditioned space, due to the tight coupling of the occupied and attic zone air temperatures. We also found some evidence of moisture risk at the North ridge sheathing. Condensation was present for substantial periods of time, which was also associated with increased wood moisture content up to 25.9%. The monitored assembly is currently within the moisture acceptability criteria established in ASHRAE Standard 160, but it is not clear whether it will continue to be safe or fail in future winter seasons. Ongoing field observations and hygrothermal simulations will be used to more fully assess the long-term moisture risks throughout California

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Elastomer and Plastic Compatibility with a Pyrolysis-derived Bio-oil

The compatibility of fueling infrastructure elastomers and plastics in bio-oil and diesel fuel was determined by measuring the volume swell. The bio-oil was produced via fast pyrolysis of woody feedstocks. The elastomer materials included fluorocarbons, acrylonitrile butadiene rubbers, neoprene, polyurethane, neoprene, styrene butadiene (SBR) and silicone. The plastic materials included polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyoxymethylene (POM), POM copolymer, high density polyethylene (HDPE), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene terephthalate glycol (PETG), polythiourea (PTU), four nylon grades, and four thermosetting resins. The majority of the elastomer and plastic materials exhibited higher volume expansion in bio-oil than in diesel. These elastomers and plastics had high polarity values which more closely align with the polarities of the bio-oil versus the diesel fuel. Conversely, SBR, silicone, HDPE, and PP are relatively nonpolar and this matches the low polarity of the diesel fuel, which resulted in higher volume expansion in diesel, rather than the bio-oil for these four polymers.

Kass, Michael↗
DOE OSTI2019

Elastomer and Plastic Compatibility with a Pyrolysis-Derived Bio-Oil

The compatibility of fueling infrastructure elastomers and plastics in bio-oil and diesel fuel was determined by measuring the volume swell. The bio-oil was produced via fast pyrolysis of woody feedstocks. The elastomer materials included fluorocarbons, acrylonitrile butadiene rubbers, neoprene, polyurethane, neoprene, styrene butadiene (SBR) and silicone. The plastic materials included polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyoxymethylene (POM), POM copolymer, high density polyethylene (HDPE), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene terephthalate glycol (PETG), polythiourea (PTU), four nylon grades, and four thermosetting resins. The majority of the elastomer and plastic materials exhibited higher volume expansion in bio-oil than in diesel. These elastomers and plastics had high polarity values which more closely align with the polarities of the bio-oil versus the diesel fuel. Conversely, SBR, silicone, HDPE, and PP are relatively nonpolar and this matches the low polarity of the diesel fuel, which resulted in higher volume expansion in diesel, rather than the bio-oil for these four polymers.

09 BIOMASS FUELS↗
DOE OSTI2019

Use of Hygrothermal Models for Understanding Water Transport in Corrosion Under Insulation Applications

Thermal insulation is used in operating facilities to conserve heat and protect against freezing amongst others. A consequence of insulating the equipment is the necessity to manage the introduced threat of corrosion under insulation (CUI). For CUI to occur, water and oxygen must enter and migrate through the insulation to reach the external surface of the equipment. The water transport characteristics are dependent on several factors such as type of insulation, type of jacketing, equipment operating temperature, external weather, water entry/leakage rate and cyclic service. In hot piping, there are competing water transport characteristics, as in water vapor moves outwards away from the equipment as water enters insulation. Knowing the water transport and the parameters that influence the time of wetness at the metal surface helps in understanding conditions favoring CUI.The use of transient hygrothermal models for moisture control is well established in the building insulation design codes and standards. The building designs naturally shed the liquid water to minimize entry and facilitate vapor management so that moisture doesn’t accumulate within building. Several building industry hygrothermal models have been developed and are available for commercial use. One such commercial model has been used to understand water transport in a CUI application. The case study involves evaluation of piping and equipment installed with a closed cell polyurethane insulation. The hygrothermal model provided insights on the parameters influencing the time of wetness and the ease of water escaping the equipment-insulation-jacketing system.

Venkateswaran, Sai P.↗
DOE OSTI2020

NREL's Capabilities in Algae-Based Chemicals, Polymers, and Fuels

NREL is advancing research and development (R&D) to maximize photosynthetic carbon capture into biomass for conversion to a broad portfolio of valuable products. Areas of focus include: (1) Carbon capture improvement through photosynthesis engineering; (2) Biotechnology and genetic toolbox development for broad species portfolio; (3) Conversion and fractionation of algal biomass to create high-value products and fuels; (4) Biological seaweed conversion to volatile fatty acids as fuel and product feedstocks; (5) Novel polyurethane production synthesis from fully renewable algae-based feedstocks; (6) Advanced analytical characterization of biomass feedstocks; and (7) Process techno-economic and life cycle modeling.

algae↗
DOE OSTI2020

Surface modification of polymer foams using plasma

An embodiment includes a system comprising: a monolithic shape memory polymer (SMP) foam having first and second states; wherein the SMP foam includes: (a) polyurethane, (b) an inner half portion having inner reticulated cells defined by inner struts, (c) an outer half portion, having outer reticulated cells defined by outer struts, surrounding the inner portion in a plane that provides a cross-section of the SMP foam, (d) hydroxyl groups chemically bound to outer surfaces of both the inner and outer struts. Other embodiments are discussed herein.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

BETO 2021 Peer Review - CAP Process Research

Combined Algal Processing (CAP) is an algae biorefining approach that employs pretreatment and extraction operations to fractionate algal biomass into an organic liquid phase containing lipids, an aqueous hydrolysate phase containing carbohydrates and protein, and a residual solid phase containing insoluble matter. Each of these fractions is upgraded to fuels and/or co-products, including non-isocyanate polyurethanes from unsaturated lipids, fuels from saturated lipids, fuel precursor carboxylic acids from the hydrolysate, and conductive carbons from the solid residue. Techno-economic analysis of multiple CAP configurations suggests that some configurations have a viable pathway to algal biofuels at $2.50/gallon of gasoline equivalent.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

Accelerating Materials Discovery: Artificial Intelligence for Sustainable, High-Performance Polymers

PolyID enables the discovery of polymers with advanced performance and greater sustainability while reducing material development timelines. The material design space is immense and cannot be reasonably probed using an Edisionian approach. High-throughput property prediction, enabled by artificial intelligence provides a hypothesis driven approach for down selection of candidate polymers to pursue experimentally. To aid experimentalists in the down selection of material targets this high-throughput, machine learning-based tool is capable of predicting polymer properties simply from molecular structures. Currently, transport, thermal, and mechanical properties across 7 polymer class (polyamides, polyesters, polycarbonates, polyimides, polyolefins, polyacrylates, and polyurethanes) can be predicted, and the PolyID platform has been flexibly designed so new materials and properties can be added.

artificial intelligence↗
DOE OSTI2021

Cyclic bend over sheave performance of a steel tension member belt for wave energy conversion

Rotary power take-offs (PTOs) promise many benefits for commercial wave energy converters (WECs), including longer power strokes/reduced end-stop concerns, deployment advantages, and controllability. However, these winch-type PTOs can impose millions of bending cycles on the belt or rope element every year, which may lead to a failure mode known as Cyclic Bend Over Sheave, or “CBOS”. Synthetic rope, though attractive due to its high strength, low elongation, and durability, suffers from comparatively poor CBOS performance and struggles to reach a million load cycles without failing. Using belts instead of ropes for winching elements should improve CBOS performance due to having a smaller thickness that undergoes bending. Unfortunately, belts have their own host of problems. Maintaining even tension across the width of a belt subject to twist or fleet angles is a challenge, especially for WECs which can move in all 6 degrees of freedom in the ocean. This study sought to quantify the CBOS performance of a belt constructed of steel tension members in a polyurethane matrix containing longitudinal profiles. Belt samples were tested to failure or up to two million bend-unbend cycles and subject to a range of fleet angles. This paper summarizes the utilized testing methodology and the resulting belt performance.

16 TIDAL AND WAVE POWER↗
DOE OSTI2023

THE IMPACT OF VISCOSITY ON MATERIAL TRANSITIONS IN LARGE FORMAT ADDITIVE MANUFACTURING OF POLYMER COMPOSITES

The need to produce complex geometries incompatible with traditional manufacturing techniques has fueled rapid growth in Large-Format Additive Manufacturing (LFAM). Printing of polymer composite materials have generated significant interest, but the production of Multi-Material (MM) structures with location-based material properties continues to be a challenge. Extrusion-based techniques have utilized multiple deposition heads to successfully print MM structures with both stiff and flexible regions, but these techniques often result in discrete material boundaries that concentrate stress and act as failure points. To avoid discrete interfaces, a novel dual-hopper configuration was developed for the Big Area Additive Manufacturing (BAAM) system that creates a blended material region within the structure. The ability to blend and freely switch between stiff polymer composites and flexible polymers enables printing of robust MM structures with site-specific properties. This study characterizes the influence of viscosity on a blended material transition between carbon fiber-filled acrylonitrile butadiene styrene (CF-ABS) and unfilled thermoplastic polyurethane (TPU), which have significantly different viscoelastic behaviors

Brackett, James↗