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This home garnered an award in the Affordable Builder category of the 2014 Housing Innovation Awards, and features 2x4 walls with fiberglass batt inside plus R-3 rigid foam on the exterior, ENERGY STAR lighting, appliances, and ceiling fans, a solar water heater, an energy recovery ventilation, and a high efficiency heat pump.
This case study describes a DOE Zero Energy Ready Home in Spirit Lake, Iowa, that scored HERS 41 without PV and HERS 28 with PV. This 3,048 ft2 custom home has advanced framed walls filled with 1.5 inches closed-cell spray foam, a vented attic with spray foam-sealed top plates and blown fiberglass over the ceiling deck. R-23 basement walls are ICF plus two 2-inch layers of EPS. The house also has a mini-split heat pump, fresh air fan intake, and a solar hot water heater.
The first Challenge Home built in New England features cool-roof shingles, HERS 20–42, and walls densely packed with blown fiberglass. This house won a 2013 Housing Innovation Award in the custom builder category.
This single-family home built in a peat bog has underground storage tanks and drainage tanks, blown fiberglass insulation, coated rigid polyisocyanurate, and flashing. The 3,600-square-foot custom home built by Weiss Building & Development LLC is the first home in Illinois certified to the DOE Challenge Home criteria, which requires that homes meet the EPA Indoor airPlus guidelines.The builder won a 2013 Housing Innovation Award in the custom builder category.
Designed to produce as much energy as it uses, the ZeroHouse incorporates a PV system, R-15 fiberglass batts in walls, and slab-on-grade foundation. The builder ranked fifth in the nation on Builder Magazine’s 2012 Top 100 ranking of U.S. home builders based on number of housing starts, and won a 2013 Housing Innovation Award in the production builder category.
Case study of a DOE 2015 Housing Innovation Award winning custom home in the cold climate that got a HERS 30 without PV, with 2x8 24” on center walls with blown fiberglass and 4” polysio rigid foam; basement with 2” XPS interior, 4” under slab, 4” exterior of foundation wall; vented attic with R-100 blown cellulose; wo air-to-air heat pumps SEER 14.1; HSPF 9.6; heat pump water heater.
Case study of a DOE 2015 Housing Innovation Award winning production home in the mixed-dry climate that got a HERS 44 without PV, or HERS -2 with PV, with 2x4 walls 16” on center walls with R-15 cavity plus 1” EPS exterior rigid foam, slab on grade with R-10 slab edge; unvented attic with R-38 blown fiberglass netted to underside of roof deck; 19 SEER heat pump; heat pump water heater; 100% LED.
Case study of a DOE 2015 Housing Innovation Award winning custom home in the mixed humid climate that got a HERS 41 without PV, with 2x4 16” on-center walls with 1 inch rigid foam, a sealed conditioned crawl space insulated on inside with 2 inches poly iso, a vented attic with R-38 blown fiberglass, a central heat pump with fresh air intake.
Case study of a DOE 2015 Housing Innovation Award winning custom home in the cold climate that got a HERS 30 without PV, with 2x8 24” on center walls with blown fiberglass and 4” polysio rigid foam; basement with 2” XPS interior, 4” under slab, 4” exterior of foundation wall; vented attic with R-100 blown cellulose; wo air-to-air heat pumps SEER 14.1; HSPF 9.6; heat pump water heater.
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).
This case study by the U.S. Department of Energy’s Building America research team Building Science Corporation is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, Florida; zone 2A), insulated with air-permeable insulation (netted and blown fiberglass).
Double wall technologies utilizing wood framing have been well-known and used in North American buildings for decades. Most of double wall designs use only natural materials such as wood products, gypsum, and cellulose fiber insulation, being one of few building envelope technologies achieving high thermal performance without use of plastic foams or fiberglass. Today, after several material and structural design modifications, these technologies are considered as highly thermally efficient, sustainable option for new constructions and sometimes, for retrofit projects. Following earlier analysis performed for U.S. Department of Energy by Fraunhofer CSE, this paper discusses different ways to build double walls and to optimize their thermal performance to minimize the space conditioning energy consumption. Description of structural configuration alternatives and thermal performance analysis are presented as well. Laboratory tests to evaluate thermal properties of used insulation and whole wall system thermal performance are also discussed in this paper. Finally, the thermal loads generated in field conditions by double walls are discussed utilizing results from a joined project performed by Zero Energy Building Research Alliance and Oak Ridge National Laboratory (ORNL), which made possible evaluation of the market viability of low-energy homes built in the Tennessee Valley. Experimental data recorded in two of the test houses built during this field study is presented in this work.
The United States Coast Guard (USCG) constructs residential housing throughout the country using a basic template that must meet the minimum Leadership in Energy and Environmental Design (LEED) Silver criteria or better for the units. In Kodiak, Alaska, USCG is procuring between 24 and 100 residential multi-family housing units. Priorities for the Kodiak project were to reduce overall energyconsumption by at least 20% over existing units, improve envelope construction, and evaluate space heating options. USCG is challenged with maintaining similar existing units that have complicated residential diesel boilers. Additionally, fuel and material costs are high in Kodiak. While USCG has worked to optimize the performance of the housing units with principles of improved buildingenvelope, the engineers realize there are still opportunities for improvement, especially within the heating, ventilation, and air conditioning (HVAC) system and different envelope measures. USCG staff also desires to balance higher upfront project costs for significantly reduced life-cycle costs of the residential units that have an expected lifetime of 50 or more years. To answer thesequestions, this analysis used the residential modeling tool BEoptE+ to examine potential energy- saving opportunities for the climate. The results suggest criteria for achieving optimized housing performance at the lowest cost. USCG will integrate the criteria into their procurement process. To achieve greater than 50% energy savings, USCG will need to specify full 2x 6 wood stud R-21 insulationwith two 2 inches of exterior foam, R-38 ceiling insulation or even wall insulation in the crawl space, and R-49 fiberglass batts in a the vented attic. The air barrier should be improved to ensure a tight envelope with minimal infiltration to the goal of 2.0 ACH50. With the implementation of an air source heat pump for space heating requirements, the combination of HVAC and envelope savings inthe residential unit can save up to 58% in source energy over existing residential units.
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
In plastics and rubber manufacturing, fossil fuels are consumed both as an energy source and as feedstocks that are converted to higher-value products. For example, in the manufacture of polyethylene, natural gas is consumed both as a fuel and as a feedstock during ethylene production. In this work, we expand on the U.S. Department of Energy's Bandwidth Study on Energy Use and Potential Energy Savings Opportunities in U.S. Plastics and Rubber Manufacturing, which quantified onsite fuel consumption and the potential for reducing fuel consumption by increasing energy efficiency in the plastics and rubber sector. The bandwidth study did not quantify fuel consumed upstream in the supply chain or as a feedstock; however, both contribute significantly to a plastic's total fossil fuel requirements. The U.S. Energy Information Administration's 2014 Manufacturing Energy Consumption Survey (MECS) estimates that fossil fuels consumed as feedstocks account for approximately 74% of total fossil fuel consumption in the U.S. plastic resin manufacturing sector (NAICS 325211). We employ the Materials Flows through Industry (MFI) supply chain modeling tool, developed at the National Renewable Energy Laboratory (NREL), to quantify process fuel and feedstock requirements within the supply chains of the same 10 categories of plastics and rubber commodities covered in the DOE bandwidth report. From these results, we identify supply chains that will have a high feedstock requirement even when energy efficiency is increased. We then use MFI to analyze several alternative plastics supply chains, including those utilizing biomass feedstocks and/or polyethylene terephthalate (PET) waste upcycling, to determine if these alternatives can potentially reduce both process fuel and feedstock requirements within the supply chains of interest. This presentation will include a case study comparison of supply chain energy consumption for petroleum-derived and bio-derived fiberglass reinforced plastic involving a novel waste PET upcycling technique recently discovered by NREL researchers.
Case study of a DOE 2016 Housing Innovation Award winning custom home in a cold climate that got a HERS 2 with PV, with double stud walls, a daylight basement with interior rigid foam, an attic insulated along roof line with R-80 dense-packed fiberglass, an air-to-water CO2 heat pump for radiant floor heat and hot water, and a ductless mini-split heat pump for cooling.
Case study of a DOE 2016 Housing Innovation Award winning custom home in a cold climate that got a HERS 46 without PV, with 2x6 advanced framed walls with dense-packed blown fiberglass, an insulated basement, a vented R-60 attic, and a natural-gas multi-stage furnace.
In 2021, the National Renewable Energy Laboratory (NREL) supported Verdant Power with the most successful tidal energy deployment in U.S. history. Three of their tidal turbines were deployed as part of the Roosevelt Island Tidal Energy project. Initially, the three rotors were manufactured from glass fiber-reinforced epoxy composites. Midway through the deployment, one rotor was replaced with one manufactured at NREL. Instead, it was infused with a novel, infusible thermoplastic resin system. Since the deployment, one epoxy rotor and one thermoplastic rotor were returned to NREL for continued materials and manufacturing research. The two rotors underwent full-scale structural testing before being sectioned and cut into specimens for a variety of manufacturing quality tests, thermos-mechanical characterization, and evaluation of material performance in marine environments, to understand the key differences between the fiberglass reinforced epoxy and Elium composites used for the respective rotors. Matrix burnoff tests showed that the Elium blades had a considerably higher fiber volume fraction compared to the epoxy blades (61% vs. 49%). Environmental aging of the specimens showed that the epoxy laminates absorbed more water over the conditioning period, however, it was determined that the Elium laminates had higher diffusion coefficients, so initially absorbed water faster. Finally, one full epoxy blade and one full Elium blade were conditioned at ambient temperatures for up to 11 months, while taking periodic mass measurements. The datasets were extrapolated out to assume a full 20 year operational life span and it was determined that the blades would not reach full saturation during that time span.