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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

Lightweight, Thermally Insulating Structural Panels

Lightweight, thermally insulating panels that also serve as structural members developed. Honeycomb-core panel filled with low-thermal-conductivity, opacified silica aerogel preventing convection and minimizes internal radiation. Copper coating on face sheets reduces radiation. Overall thermal conductivities of panels smaller than state-of-art commercial non-structurally-supporting foam and fibrous insulations. On Earth, panels suitable for use in low-air-pressure environments in which lightweight, compact, structurally supporting insulation needed; for example, aboard high-altitude aircraft or in partially evacuated panels in refrigerators.

Eisen, Howard J.↗

Transient Thermal Testing and Analysis of a Thermally Insulating Structural Sandwich Panel

A core configuration was devised for a thermally insulating structural sandwich panel. Two titanium prototype panels were constructed to illustrate the proposed sandwich panel geometry. The core of one of the titanium panels was filled with Saffil(trademark) alumina fibrous insulation and the panel was tested in a series of transient thermal tests. Finite element analysis was used to predict the thermal response of the panel using one- and two-dimensional models. Excellent agreement was obtained between predicted and measured temperature histories.

Blosser, Max L.↗

Design Considerations for Thermally Insulating Structural Sandwich Panels for Hypersonic Vehicles

Simplified thermal/structural sizing equations were derived for the in-plane loading of a thermally insulating structural sandwich panel. Equations were developed for the strain in the inner and outer face sheets of a sandwich subjected to uniaxial mechanical loads and differences in face sheet temperatures. Simple equations describing situations with no viable solution were developed. Key design parameters, material properties, and design principles are identified. A numerical example illustrates using the equations for a preliminary feasibility assessment of various material combinations and an initial sizing for minimum mass of a sandwich panel.

Blosser, Max L.↗

Nexus EnergyHomes, Frederick, Maryland (Fact Sheet)

With this new home - which achieved the highest rating possible under the National Green Building Standard - Nexus EnergyHomes demonstrated that green and affordable can go hand in hand. The mixed-humid climate builder, along with the U.S. Department of Energy Building America team Partnership for Home Innovation, embraced the challenge to create a new duplex home in downtown Frederick, Maryland, that successfully combines affordability with state-of-the-art efficiency and indoor environmental quality. To limit costs, the builder designed a simple rectangular shape and kept interesting architectural features such as porches outside the building's structure. This strategy avoided the common pitfall of creating potential air leakage where architectural features are connected to the structure before the building is sealed against air infiltration. To speed construction and limit costs, the company chose factory-assembled components such as structural insulated panel walls and floor and roof trusses. Factory-built elements were key in achieving continuous insulation around the entire structure. Open-cell spray foam at the rim joist and attic roofline completed the insulation package, and kept the heating, ventilating, and air-conditioning system in conditioned space.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

New Whole-House Solutions Case Study: Nexus EnergyHomes, Frederick, Maryland

With this new home—which achieved the highest rating possible under the National Green Building Standard—Nexus EnergyHomes demonstrated that green and affordable can go hand in hand. The mixed-humid climate builder, along with the U.S. Department of Energy Building America team Partnership for Home Innovation, embraced the challenge to create a new duplex home in downtown Frederick, Maryland, that successfully combines affordability with state-of-the-art efficiency and indoor environmental quality. To limit costs, the builder designed a simple rectangular shape and kept interesting architectural features such as porches outside the building’s structure. This strategy avoided the common pitfall of creating potential air leakage where architectural features are connected to the structure before the building is sealed against air infiltration. To speed construction and limit costs, the company chose factory-assembled components such as structural insulated panel walls and floor and roof trusses. Factory-built elements were key in achieving continuous insulation around the entire structure. Open-cell spray foam at the rim joist and attic roofline completed the insulation package, and kept the heating, ventilating, and air-conditioning system in conditioned space.

affordable↗

Super Energy Efficiency Design (S.E.E.D.) Home Evaluation

This report describes the results of evaluation by the Alliance for Residential Building Innovation (ARBI) Building America team of the 'Super Energy Efficient Design' (S.E.E.D) home, a 1,935 sq. ft., single-story spec home located in Tucson, AZ. This prototype design was developed with the goal of providing an exceptionally energy efficient yet affordable home and includes numerous aggressiveenergy features intended to significantly reduce heating and cooling loads such as structural insulated panel (SIP) walls and roof, high performance windows, an ERV, an air-to-water heat pump with mixed-mode radiant and forced air delivery, solar water heating, and rooftop PV. Source energy savings are estimated at 45% over the Building America B10 Benchmark. System commissioning, short termtesting, long term monitoring and detailed analysis of results was conducted to identify the performance attributes and cost effectiveness of the whole house measure package.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Super Energy Efficient Design (S.E.E.D.) Home Evaluation

This report describes the results of evaluation by the Alliance for Residential Building Innovation (ARBI) Building America team of the “Super Energy Efficient Design” (S.E.E.D) home, a 1,935 sq. ft., single-story spec home located in Tucson, AZ. This prototype design was developed with the goal of providing an exceptionally energy efficient yet affordable home and includes numerous aggressive energy features intended to significantly reduce heating and cooling loads such as structural insulated panel (SIP) walls and roof, high performance windows, an ERV, an air-to-water heat pump with mixed-mode radiant and forced air delivery, solar water heating, and rooftop PV. Source energy savings are estimated at 45% over the Building America B10 Benchmark. System commissioning, short term testing, long term monitoring and detailed analysis of results was conducted to identify the performance attributes and cost effectiveness of the whole house measure package.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Preliminary design procedure for insulated structures subjected to transient heating

Minimum-mass designs were obtained for insulated structural panels loaded by a general set of inplane forces and a time dependent temperature. Temperature and stress histories in the structure are given by closed-form solutions, and optimization of the insulation and structural thicknesses is performed by nonlinear mathematical programming techniques. Design calculations are described to evaluate the structural efficiency of eight materials under combined heating and mechanical loads: graphite/polyimide, graphite/epoxy, boron/aluminum, titanium, aluminum, Rene 41, carbon/carbon, and Lockalloy. The effect on design mass of intensity and duration of heating were assessed. Results indicate that an optimum structure may have a temperature response well below the recommended allowable temperature for the material.

Adelman, H. M.↗

Validation of Hygrothermal Simulations with Wall Performance Experiments in an Environmental Chamber

Oak Ridge National Laboratory is developing a web tool, built on a rule-based expert system, that aids stakeholders in designing energy-efficient moisture-durable walls. Currently, the tool’s expert system database is mostly populated with expert opinion, but work is being done to incorporate durability assessment based on stochastic hygrothermal modeling. Chamber experiments have been conducted to validate the hygrothermal models. The measured temperature and humidity have been compared with those predicted by the hygrothermal model. Experiments and comparison to one-dimensional hygrothermal modeling results were completed with two walls, a Structural Insulated Panel (SIP) based wall and a Concrete Masonry Unit (CMU) based wall. The two walls were succumbed to typical Chicago weather in ORNL’s Heat, Air and Moisture chamber. The walls were sequentially exposed to different scenarios, including diffusion, wetting, air leakage and solar radiation. For the most part, the hygrothermal simulations can be successfully used to predict the performance of these wall systems for the moisture transport phenomenon. Errors between measured and simulated values decreased as measurements got closer to the interior side of the wall. The root mean square error was larger for relative humidity (up to 17.5%-RH for CMU) than for temperature (up to 4.5°C for CMU wall). The errors were larger for the CMU wall than the wood frame wall. The phenomenon, including liquid water, caused large discrepancies between measurement and simulation results, and simulated results showed slower drying of materials than measured results. The one-dimensional nature of the simulation model made simulating air leaks difficult but not impossible.

Salonvaara, Mikael↗

Columbia County Habitat for Humanity Passive Townhomes

Columbia County (New York) Habitat for Humanity built a pair of townhomes to Passive House criteria with the purpose of exploring approaches for achieving Passive House performance and to eventually develop a prototype design for future projects. The project utilized a 2x6 frame wall with a structural insulated panel curtain wall and a ventilated attic over a sealed OSB ceiling air barrier. Mechanical systems include a single head, wall mounted ductless mini-split heat pump in each unit and a heat recovery ventilator. Costs were $26,000 per unit higher for Passive House construction compared with the same home built to ENERGY STAR version 3 specifications, representing about 18% of total construction cost. This report discusses the cost components, energy modeling results and lessons from construction. Two alternative ventilation systems are analyzed: a central system; and, a point-source system with small through-wall units distributed throughout the house. The report includes a design and cost analysis of these two approaches.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Comparing wall performance predicted from hygrothermal simulations to wall performance measured from environmental chamber experiments

To effectively mitigate prevailing perceptions of potential moisture risks in high-R wall assemblies, a comprehensive moisture durability assessment that incorporates BA team field evaluations, lab tests and simulations has been completed over the last couple years. In FY18, three stick-built walls were succumbed to typical Chicago weather in ORNL’s Heat, Air and Moisture chamber. The measured temperature, relative humidity and moisture content within these walls were compared to WUFI hygrothermal simulation results. In FY19, similar experiments and comparison to WUFI results were completed with two walls, a Structural Insulated Panel (SIP) based wall and a Concrete Masonry Unit (CMU) based wall. The following tasks were completed for these two walls: 1. Measure air permeance of each individual wall using ASTM E283 Standard Test Method. 2.Test walls in diffusion scenario as only moisture transport mechanism and compare measured transient temperature and relative humidity of select wall components to WUFI model results. Chicago summer and weather will be investigated. 3. Test walls in wetting event scenario and compare measured transient temperature and relative humidity of select wall components with Chicago summer weather to WUFI model results. 4. Test walls in diffusion/advection scenario. In addition to controlling outdoor chamber to match real outdoor weather, a pressure differential across the wall will be varied. Measured transient temperature and relative humidity of select wall components will be compared to WUFI model results. 5. Test walls in diffusion/advection with solar heating of cladding. In addition to the variables above, IR lamps will be used to heat the cladding on a diurnal cycle. Measured transient OSB MC and temperature will be compared to WUFI model results. This report documents the experimental method, results and comparison of the measured experimental hygrothermal performance of the two walls to simulations results.

42 ENGINEERING↗

DOE Zero Energy Ready Home Case Study: TC Legend Homes — Cedarwood, Bellingham, WA

This house was the Grand Winner in the Affordable Builder category of the 2014 Housing Innovation Awards, and has 6-inch SIP walls, a 10-inch structural insulated panel roof, and insulating concrete forms foundation walls with R-20 high-density rigid EPS foam under the slab.A single ductless heat pump heats and cools the home, which also gets passive solar heating from south-facing triple-pane windows that heat a concrete slab floor plus a connected greenhouse.

2014 housing innovation awards↗

DOE Zero Energy Ready Home Case Study: Leganza Residence - Greenbank, Washington

This case study describes a DOE Zero Energy Ready Home in Greenbank, Washington that scored HERS 37 without PV and a -5 with PV. This 1,955 ft2 custom home has 6.5-inch structural insulated panel (SIPs) walls, a 10.25-inch SIPS roof, an R-20 insulated slab, a 2-ton ground source heat pump, radiant floor heat, 7.1 kWh PV, and triple-pane windows.

builder↗

Building America Case Study: Columbia County Habitat for Humanity Passive Townhomes, Hudson, New York

Columbia County (New York) Habitat for Humanity built a pair of townhomes to Passive House criteria with the purpose of exploring approaches for achieving Passive House performance and to eventually develop a prototype design for future projects. The project utilized a 2x6 frame wall with a structural insulated panel curtain wall and a ventilated attic over a sealed OSB ceiling air barrier. Mechanical systems include a single head, wall mounted ductless mini-split heat pump in each unit and a heat recovery ventilator. Costs were $26,000 per unit higher for Passive House construction compared with the same home built to ENERGY STAR version 3 specifications, representing about 18 percent of total construction cost. This report discusses the cost components, energy modeling results and lessons from construction. Two alternative ventilation systems are analyzed: a central system; and, a point-source system with small through-wall units distributed throughout the house. The report includes a design and cost analysis of these two approaches.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Comparing Retrofit Wall Performance Predicted from Hygrothermal Simulations to Measurements

Over the past few years ORNL has been showing that WUFI® can be used to predict the moisture performance of walls when exposed to diffusion of water vapor, convection of moist air through the wall, and solar driven moisture. This is accomplished by comparing the hygrothermal simulation results to carefully instruments walls exposed to these phenomena in a climate chamber. In FY 2018, three stick-built walls were succumbed to typical Chicago, Illinois weather conditions in Oak Ridge National Laboratory’s Heat, Air and Moisture chamber. The measured temperature, relative humidity, and moisture content within these walls were compared with WUFI hygrothermal simulation results. In FY 2019, similar experiments and comparisons with WUFI results were completed with two walls, a structural insulated panel-based wall and a concrete masonry unit-based wall. In FY 2020, experiments were completed for a probable exterior retrofit of a wall which included adding cavity and continuous insulation. Two pairs of walls were tested by exposing them to Chicago winter weather with a positive pressure pushing outside air into the wall. The results from the FY 2020 experiments are reported here.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Impact of Insulation Strategies of Cross-Laminated Timber Assemblies on Energy Use, Peak Demand, and Carbon Emissions

Cross-Laminated Timber (CLT) panels have many structural benefits but do not have much thermal resistance. We have developed a solution to insulate CLT structures that uses high-performance insulation panels that provide R-values up to R40/inch. The CLT panels are made of layers of wood laminates (three, five, seven or more). The solution replaces some of the wood laminates in the CLT production with the insulation panels in a staggered fashion so that the wood laminates maintain contact throughout the panel, ensuring the CLT panel’s structural integrity. The insulated CLT panels have factory-installed water-resistive barriers reducing the installation time by eliminating installing insulation and water-resistive barriers on site. Per simulations, the CLT/insulation panel achieved code-required insulation levels with commonly available insulation materials. The significance of the thermal mass of CLT/insulation hybrid building envelopes was quantified by comparing the whole building energy performance and peak demand of traditional low mass and CLT wall assemblies resulting in up to 7% reduction in peak demand for cooling in Knoxville, TN, in a multifamily building. Buildings contribute over 40 percent of carbon emissions. The proposed CLT/insulation hybrid building envelope addresses both operational and embodied carbon by having high thermal resistances due to the embedded insulation sections and eliminating the use of high embodied carbon materials such as steel and concrete. The carbon benefit is estimated.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Insulated Honeycomb

Proposed insulated honeycomb structure similar to reinforced honeycomb structure described in NPO-17538. Panels of insulated honeycomb used to make supports for solar-energy collectors and radar antennas.

Bhat, Balakrishna T.↗