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At least 73 records · Page 4

Assessing the New Home Market Opportunity: Case Study and Cost Modeling for Solar and Storage in 2030

Residential solar and storage markets are growing in the United States. With approximately 1 million new homes constructed every year, this represents a significant opportunity for solar and storage installations. Some homebuilders have begun to build new homes with solar and storage included as a standard offering. It is not clear how solar and storage is incorporated into the new construction process and at what cost. Further, it is unclear what barriers or opportunities exist to scale this model nationwide. To fill this gap in the literature, this research conducts a case study of Mandalay Homes' new solar and storage community in Arizona to gather lessons learned. From this foundation, we further generate a set of pathways to reduce install costs and expand solar and storage market penetration in this sector. To model existing and 2030 solar and storage costs, we use the National Renewable Energy Laboratory's (NREL's) bottom-up cost model. This modeling is further informed by 12 interviews conducted with new home builders, solar contractors, and other subject matter expert organizations. Our case study analysis generated three key considerations for other homebuilders including: 1. Educating local permitting, inspection, and in some cases utility officials on solar and storage products, designs, and code compliant building practices may be required. The need for education may decline as more local governments and utilities review and approve solar and storage projects. 2. Incorporating solar and storage systems into the homebuilding process can add complexity and related coordination challenges. This does not need to result in home construction delays, but can result in costly contractor "dry runs" to construction sites. 3. Deploying solar and storage at the time of new construction has significant economies of scale, which can improve the value proposition of the systems. The case study, extant literature, and interviews were used to model both existing and future solar and storage installation costs at time of new construction. Here, we find three key cost reduction opportunities relating to solar and battery storage hardware, customer acquisition, and overhead. If future contractors can maximize the cost reduction opportunities outlined here, residential new construction costs could decline by 8 - 25% by 2030, depending on the modeled scenario. Though we expect costs to decline through 2030, it is unclear which of these scenarios may ultimately appear. Interviewees further identified a variety of barriers across each cost category that could temper the savings shown here. At the same time, interviewees described several pathways to scale the new construction solar and storage market, beyond installation cost savings. Interviewees confirmed that changes in finance, rate design, resilience policies, deployment mandates, and DER aggregation could all support more market adoption than seen today. These findings suggest that there are significant opportunities to expand new construction markets and this research can serve as a baseline to assess progress in this segment through 2030.

14 SOLAR ENERGY↗

A Program Design Combining Community Solar and Weatherization for Manufactured Homes in Michigan

The Michigan Department of Environment, Great Lakes, and Energy (EGLE) is interested in combining community solar with weatherization programs for manufactured homes. To collect program strategies, EGLE made a request for technical assistance from the US Department of Energy’s National Community Solar Partnership (NCSP). Lawrence Berkeley National Lab developed this study in response. It briefly reviews issues relevant to the question, attempts to lay out a methodology for more in-depth analysis, and provides some recommendations for program design and implementation. While the research is specific to Michigan, the recommendations and methodologies could serve as an example for other states and regions. The paper first provides an overview of manufactured home communities in Michigan, with a discussion of demographics and energy issues they face. It then discusses weatherization opportunities for manufactured homes, opportunities for community solar, and opportunities for combining the two. The methodology proposed is intended to help EGLE: -Identify priority locations, -Set eligibility criteria for communities and households, and -Make the most of federal and other funding sources The paper concludes with recommendations for a program that combines community solar with efficient electrification of manufactured homes to reduce the burden of the largest source of energy expenditure in Michigan, winter heating bills. Specifically, it envisions community solar subscriptions for occupants of manufactured homes that have been converted to high-efficiency cold weather heat pumps. The combination can be managed to alleviate seasonal variations in both solar and heating bills, such as through an annualized “budget billing” program.

14 SOLAR ENERGY↗

Homing orientation in salamanders: A mechanism involving chemical cues

A detailed description is given of experiments made to determine the senses and chemical cues used by salamanders for homing orientation. Sensory impairment and cue manipulative techniques were used in the investigation. All experiments were carried out at night. Results show that sense impaired animals did not home as readily as those who were blind but retained their sensory mechanism. This fact suggests that the olfactory mechanism is necessary for homing in the salamander. It was determined that after the impaired salamander regenerated its sensory mechanism it too returned home. It was concluded that homing ability in salamanders is direction independent, distant dependent, and vision independent.

Madison, D. M.↗

HOME - An application of fault-tolerant techniques and system self-testing

Hard Over Monitoring Equipment (HOME) has been designed to complement and enhance the flight safety of a flight research helicopter. HOME is an independent, highly reliable, and fail-safe special purpose computer that monitors the flight control commands issued by the flight control computer of the helicopter. In particular, HOME detects the issuance of a hazardous hard-over command for any of the four flight control axes and transfers the control of the helicopter to the flight safety pilot. The design of HOME incorporates certain reliability and fail-safe enhancement design features, such as triple modular redundancy, majority logic voting, fail-safe dual circuits, independent status monitors, in-flight self-test, and a built-in preflight exerciser. The HOME design and operation is described with special emphasis on the reliability and fail-safe aspects of the design.

Holden, D. G.↗

Effect of stromal-cell-derived factor 1 on stem-cell homing and tissue regeneration in ischaemic cardiomyopathy

BACKGROUND: Myocardial regeneration via stem-cell mobilisation at the time of myocardial infarction is known to occur, although the mechanism for stem-cell homing to infarcted tissue subsequently and whether this approach can be used for treatment of ischaemic cardiomyopathy are unknown. We investigated these issues in a Lewis rat model (ligation of the left anterior descending artery) of ischaemic cardiomyopathy. METHODS: We studied the effects of stem-cell mobilisation by use of granulocyte colony-stimulating factor (filgrastim) with or without transplantation of syngeneic cells. Shortening fraction and myocardial strain by tissue doppler imaging were quantified by echocardiography. FINDINGS: Stem-cell mobilisation with filgrastim alone did not lead to engraftment of bone-marrow-derived cells. Stromal-cell-derived factor 1 (SDF-1), required for stem-cell homing to bone marrow, was upregulated immediately after myocardial infarction and downregulated within 7 days. 8 weeks after myocardial infarction, transplantation into the peri-infarct zone of syngeneic cardiac fibroblasts stably transfected to express SDF-1 induced homing of CD117-positive stem cells to injured myocardium after filgrastim administration (control vs SDF-1-expressing cardiac fibroblasts mean 7.2 [SD 3.4] vs 33.2 [6.0] cells/mm2, n=4 per group, p<0.02) resulting in greater left-ventricular mass (1.24 [0.29] vs 1.57 [0.27] g) and better cardiac function (shortening fraction 9.2 [4.9] vs 17.2 [4.2]%, n=8 per group, p<0.05). INTERPRETATION: These findings show that SDF-1 is sufficient to induce therapeutic stem-cell homing to injured myocardium and suggest a strategy for directed stem-cell engraftment into injured tissues. Our findings also indicate that therapeutic strategies focused on stem-cell mobilisation for regeneration of myocardial tissue must be initiated within days of myocardial infarction unless signalling for stem-cell homing is re-established.

NASA Discipline Cardiopulmonary↗

An East to West Mineralogical Trend in Mars Exploration Rover Spirit Moessbauer Spectra of Home Plate

Home Plate is a light-toned plateau approx.90 m in diameter within the Inner Basin of the Columbia Hills in Gusev crater on Mars. It is the most extensive exposure of layered bedrock encountered by Spirit to date, and it is composed of clastic rocks of moderately altered alkali basalt composition, enriched in some highly volatile elements. Textural observations suggest an explosive origin and geochemical observations favor volcanism, probably a hydrovolcanic explosion [1]. Since it first arrived at Home Plate on sol 744, Spirit has circumnavigated the plateau (Fig. 1) and is now, since sol 1410, resting at its Winter Haven 3 location at the north end of Home Plate. Results: The MER Moessbauer spectrometers determine Fe oxidation states, identify Fe-bearing mineral phases and quantify the distribution of Fe among oxidation states and mineral phases [2]. Moessbauer spectra of Home Plate bedrock were obtained in five different locations from nine different targets (Fig. 1): Barnhill Ace, Posey Manager, and James Cool Papa Bell Stars at the northwest side of Home Plate; Pesapallo, June Emerson, and Elizabeth Emery on the east side; Texas Chili on the south side; Pecan Pie on the west side; and Chanute on the north side.

Schroder, C.↗

Achieving 50% Energy Savings in Chicago Homes: A Case Study for Advancing Equity and Climate Goals

Since 2019, the National Renewable Energy Laboratory (NREL) and Elevate have collaborated to identify pathways to deep energy retrofits in Chicago's housing stock, document equity implications and co-benefits of this transition, and validate the findings by implementing retrofits in real Chicago homes. This document summarizes our analysis process to model advanced retrofit packages that lead to greater than 50% energy savings in Chicago homes. Based on these findings, we have also developed a roadmap with the City to guide implementation, and are deploying the recommended retrofit packages in real Chicago homes to realize these energy savings. This work was developed in collaboration with two key stakeholders - the City of Chicago and Commonwealth Edison (ComEd) - and funded by the U.S. Department of Energy (DOE). NREL's Residential Buildings team maintains the best-in-class ResStock™ energy model of the U.S. residential building stock. For this work, we calibrated ResStock to Chicago's unique local housing stock to accurately simulate energy use in Chicago homes both for current conditions and with various retrofit scenarios. We simulated a wide range of potential building retrofits covering all aspects of residential energy use and then grouped these into packages based on energy and utility bill savings. ResStock can model diverse building types and housing characteristics, so we're able to observe the range of outcomes that might occur when these upgrades are deployed across the entire housing stock. We can then estimate potential energy savings from an advanced retrofit program on Chicago's housing stock by comparing the modeled energy use before versus after a retrofit. This novel version of ResStock, calibrated to Chicago with data from Elevate, can help City officials, ComEd, and other partners plan for community-scale decarbonization via residential retrofits. Specifically, this work contributes the following project goals: Develop a building retrofit prioritization strategy for Chicago single-family and 2- to 4-unit buildings; Identify neighborhoods and home types that have the highest potential for savings from electrification; and Assess the impact of advanced building retrofits on energy use, utility bills, and CO2 emissions at the city and building level. Although this study is specific to Chicago, its methods and learnings are applicable across the United States. These findings are especially notable for heat pumps and electrification retrofits in cold climates.

building energy modeling↗

Reimagining Heating, Ventilation, and Air Conditioning for New Manufactured Homes

Manufactured homes represent one of the most affordable paths to home ownership for American households, but minimum-efficiency equipment and poor-quality home installation can lead to excess energy use and high operating costs. Slipstream, with partners from the Florida Solar Energy Center (FSEC), Northwest Energy Works, and Washington State University, identified and tested manufactured home HVAC innovations targeted for new construction offering the most promising mix of improved energy performance and likelihood of industry uptake.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Home range and resource selection of Virginia opossums in the rural southeastern United States

The Virginia opossum (Didelphis virginiana) has a rapidly expanding distribution in North America, but many aspects of its ecology remain relatively understudied, particularly in rural areas of its core range. We collected GPS telemetry data from 93 opossums in a rural, non-agricultural landscape in South Carolina, USA (2018–2019) to examine factors influencing space use and resource selection. Estimated male home ranges (99% utilization distributions) were on average 50% larger than those of females (mean home range 115.9 ± 103.7 ha vs 76.7 ± 75.0 ha). The home range size decreased on average by 20% with each 20% increase in deciduous land cover but was not affected by season or other landscape factors. Core area sizes (65% utilization distributions) were not influenced by sex (mean core area size 29.1 ± 23.7 ha and 22.4 ha ± 13.8 for males and females, respectively) or season, but the core area size decreased by 14% with each 400 m increase in distance from a permanent water source. Resource selection by opossums primarily occurred at the landscape level. Both males and females generally selected for wetlands while avoiding pine forests and developed/open areas, likely the result of differences in resource availability and predation risk between habitats. Opossums also tended to select for linear features such as unpaved roads and edge habitat, which may facilitate movement across the landscape. Finally, the home ranges we documented are among the largest recorded for opossums in the USA, likely the result of the relatively low resource abundance throughout our study area due to comparatively minimal anthropogenic influence.

59 BASIC BIOLOGICAL SCIENCES↗

Impact of model predictive control-enabled home energy management on large-scale distribution systems with photovoltaics

Residential customers use more than one-quarter of the electricity in the world. Optimally managing home energy consumption is an effective way of easing the operational challenges facing the electric grid with increasing solar photovoltaics (PV). This paper studies the impact of the future proliferation of home energy management systems (HEMS) in the presence of PV on large-scale distribution systems. First, we present a stochastic HEMS model that minimizes residential customers' thermal discomfort and energy costs under uncertainty. The HEMS model schedules the optimal operations of residential appliances in the presence of PV within a mixed-integer linear programming-based model predictive control framework that links the proposed HEMS to a quasi-steady-state time-series simulation tool. Additionally, extensive simulations are conducted for a stand-alone residential home using two tariff structures and for 1977 homes on an 8,500-node distribution feeder. Simulation results quantify the impact of the future proliferation of HEMS on the large-scale distribution system with PV.

14 SOLAR ENERGY↗

Stochastic Home Energy Management Systems with Varying Controllable Resources

This paper studies the performance of a model predictive control (MPC) algorithm in a home energy management system (HEMS) as the set of controllable resources varies and under both a constant and a time-of-use (TOU) electricity price structure. The set of controllable resources includes residentially-owned photovoltaic (PV) panels, a home battery system (HBS), an electric vehicle (EV), and a home heating, ventilation, and air conditioning (HVAC) system. The HEMS optimally schedules the set of controllable resources given user preferences such as indoor thermal comfort and electricity cost sensitivity. The home energy management system is built on a chance constrained, MPC-based algorithm, where the chance constraint ensures the indoor thermal comfort is satisfied with a high probability given uncertainty in the outdoor temperature and solar irradiance forecasts. Simulation results for varying sets of controllable resources under two different electricity price structures demonstrate the variation in the HEMS control with respect to HBS operation, electricity cost, and grid power usage.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Optimization of wall assembly for DOE Efficient New Homes Program in HUD’s Climate Zones 2 and 3

Manufactured homes provide affordable housing for over 20 million Americans. The U.S. Department of Energy’s Efficient New Homes (ENH) program has introduced new energy certification requirements that manufacturers can optionally target to ensure outstanding levels of energy savings, comfort, health, and durability. In collaboration with Clayton Homes (under User Agreement (NN-23-1469)), Oak Ridge National Laboratory evaluated multiple wall assembly options to meet ENH requirements in HUD Climate Zones 2 and 3, with a target maximum cost premium of 5%. After analyzing thermal performance, cost, and manufacturability, insulated structural sheathing was identified as the most practical and effective solution. A full-scale manufactured home prototype demonstrated that this approach meets energy performance goals with minimal disruption to existing manufacturing processes and a cost premium of less than 10% with a path to further lower costs, offering a promising path forward for more efficient manufactured housing.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Transformative Efficiency and Automation in Modular Homes (TEAMH)

This report documents the Transformative Efficiency and Automation in Modular Homes (TEAMH) project, which evaluates the integration of advanced building envelope technologies and automation-assisted modular construction to improve residential energy performance and construction efficiency. The study investigates high-performance insulation systems, including vacuum insulation panels (VIPs), combined with light gauge steel (LGS) modular construction and factory automation. Laboratory testing, whole-building energy modeling across multiple climate zones, and factory demonstrations were conducted to assess thermal performance, energy savings, and production efficiency. Results indicate that upgraded envelope assemblies can achieve up to ~50% heating and ~34% cooling energy savings relative to IECC 2018 code-compliant homes, while automation-assisted construction can reduce wall assembly time by 24%–46% compared to conventional wood framing. The findings demonstrate the potential for scalable, high-performance modular homes that deliver significant energy savings with competitive projected costs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Impacts of COVID-19 related stay-at-home restrictions on residential electricity use and implications for future grid stability

“Stay-at-home” orders and other health precautions enacted during the COVID-19 pandemic have led to substantial changes in residential electricity usage. Here, we conduct a case study to analyze data from 390 apartments in New York City (NYC) to examine the impacts of two key drivers of residential electricity usage: COVID-19 case-loads and the outdoor temperature. We develop a series of regression models to predict two characteristics of residential electricity usage on weekdays: The average occupied apartment’s consumption (kWh) over a 9am-5pm window and the hourly peak demand (Watt) over a 12pm-5pm window. Via a Monte Carlo simulation, we forecast the two usage characteristics under a possible scenario in which stay-at-home orders in NYC, or a similar metropolitan region, coincide with warm summer weather. Under the scenario, the 9am-5pm residential electricity usage on weekdays is predicted to be 15% – 24% higher than under prior, pre-pandemic conditions. This could lead to substantially higher utility costs for residents. Additionally, we predict that the residential hourly peak demand between 12pm and 5pm on weekdays could be 35% – 53% higher than that under pre-pandemic conditions. We conclude that the projected increase in peak demand - which might arise if stay-at-home guidelines coincided with hot weather conditions - could pose grid management challenges, especially for residential feeders. We also note that, if there is a longer lasting shift towards work and study-from-home, utilities will have to rethink load profile considerations. The applications of our predictive models to managing future smart-grid technology are also highlighted.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Outdoor Home Gardener Preferences for Environmental Attributes in Gardening Supplies and Use of Ecofriendly Gardening Practices

Home gardeners’ concerns for the environment are expressed both in the ecofriendly gardening practices they use and in environmental attributes they prefer in the gardening products they purchase. This study uses data from a 2018 survey of 601 Tennessee outdoor home gardeners and a multiple indicators multiple causes (MIMIC) model to illustrate how outdoor home gardener demographics, expenditures, information use, and attitudes influence use of ecofriendly gardening practices and preferences for environmental attributes in home gardening supplies. Practices considered include planting pollinator plants, using rainwater collectors, composting, recycling gardening supplies packaging, using organic gardening methods, and use of soil testing. Gardening supply product attributes include decreased need for fertilizer, pesticides, and water; native plant species; organically produced products; and recyclable packaging. The most widely used practice is recycling gardening supplies packaging, and the least used is soil testing. Gardeners with a greater propensity to use the six gardening practices include male, college graduates, who spend relatively more of their income on gardening supplies, and consider themselves as being knowledgeable about environmental issues. The gardening supply product attribute most widely considered as important is decreased need for pesticides, and least widely considered as important are native species and organically produced. Gardeners more likely to prefer the six gardening supply product attributes include older gardeners, who seek other gardeners for information, and who perceived themselves as being knowledgeable about the environment. This same group likes to grow their own food and feels responsibility for protecting the environment for future generations.

54 ENVIRONMENTAL SCIENCES↗

A Guided Approach to Setting up Your Workstation at Home [Slides]

Due to COVID-19 LANL has moved to a reality where most people are telecommuting from their homes and social distancing measures require a new normal. This requires the challenge of setting up an at home workstation to be as ergonomically friendly as possible. Sometimes space within the home is limited and office space may double as a dining space, kitchen counter or general use area. Other times, a desk and chair are present, but may not have the adjustability needed to provide a suitable long-term work environment. When setting up the home work environment remember to implement ergonomics basics.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

Reducing COVID-19 Transmission in Homes

Owners and renters all over the world are being encouraged to stay home as much as possible to mitigate the spread of the SARS CoV-2 virus and the COVID-19 disease. It is prudent to take reasonable precautions at home to decrease risks during the pandemic because most COVID-19 transmission happens in the home (see “learn more”). This is particularly true for households with infected or sensitive members. Furthermore, because people infected with COVID-19 can be asymptomatic you may have an infected person in your home for several days before you know it.

60 APPLIED LIFE SCIENCES↗

Home Energy Professionals Certifications ISO/IEC 17024: 2021 Policies and Procedures Manual

The U.S. Department of Energy (DOE) enlisted its National Renewable Energy Laboratory (NREL) to coordinate the development of a framework for new certifications in the weatherization and home performance industry. The Home Energy Professional certifications support DOE's Weatherization Assistance Program (WAP) and the broader residential home performance industry through the credentialing process of defined job task analysis for energy auditors and quality control inspectors. The HEP certifications are not intended to supplant or infringe upon any existing industry-recognized credentials, however, the WAP and the home performance industry have utilized the advanced HEP certifications to promote quality work and standardized job task analysis since 2010. On an ongoing basis, NREL brings industry practitioners and subject matter experts together to develop, review, and revise the certification schemes in accordance with the International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) 17024 standard, "Conformity assessment - General requirements for bodies operating certification of persons" (ISO/IEC 17024). This handbook covers the policies and procedures for the process of developing, maintaining, and validating the certification schemes. Each policy and procedure includes the relevant ISO/IEC 17024 section at the beginning.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗