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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Modelling moisture sources due to air leakage with the HAMT extension for EnergyPlus

The moisture performance of building envelope components is one of the main challenges of energy efficient buildings. The combined Heat and Moisture Transfer (HAMT) model in EnergyPlus can provide moisture profiles through multiple material layers of an envelope assembly using a coupled, one-dimensional, finite volume model simulating the movement and storage of heat and moisture. Currently only a limited assessment of the effects of moisture sources inside an assembly to determine impacts on durability, indoor air quality, and energy performance is possible. This paper discusses different strategies to model moisture sources in building components due to air leakage. Models that enable air leakage to result in a moisture sink/source at an arbitrary location extend the existing mass transfer equation with a source term that includes water vapor deposit from air flow through an assembly. New sub-models with different levels of complexity to calculate the air flow through the assembly are developed. The air flow can be user defined, it can be computed as a result of the stack height and a user defined ventilation overpressure or completely derived from an air-flow network. We explain the model enhancements, discuss the required inputs for every option together with related limitations, showcase the model application and make the source code publicly available for external use.

Antretter, Florian↗
DOE OSTI2022

Commercial Building Sensors and Controls Systems: Barriers, Drivers, and Costs

Building sensors and controls systems, including building automation systems, consists of the sensor-based devices installed in buildings and the control and automation of those devices. Optimized sensors and controls systems could lead to 29% annual energy savings in commercial buildings and are integral to the growth of grid-interactive efficient buildings. Only 8% of small commercial buildings, however, have installed sensors and controls systems. This is largely due to cost barriers. This work seeks to increase the transparency of system costs and identify specific barriers and drivers for increased adoption. To gather industry insights, the team reached out to building owners, vendors, and contractors and conducted 20 interviews with the goal of collecting cost data and market characteristics regarding building sensors and controls. The qualitative interview data was analyzed using grounded theory to identify overarching concepts, such as barriers, drivers, and future directions on the field. From this analysis, primary barriers were found to be complexity, a lack of knowledge, and money. Primary drivers were found to be the knowledge of data, savings, and remote access. The qualitative cost data was collected in the form of invoices during the interviews. The cost values were used to develop a percentage-based cost stack which identifies the average fraction of the total cost attributed to each category (hardware, software, labor, fees, and taxes). This greater understanding of costs and barriers associated with commercial building sensors and controls systems lays the groundwork for future steps in increasing system adoption, reducing energy consumption, and market transformation.

advanced building controls↗
DOE OSTI2022

A High-Granularity Approach to Modeling Energy Consumption and Savings Potential in the U.S. Residential Building Stock: Preprint

Building simulations are increasingly used in various applications related to energy efficient buildings. For individual buildings, applications include: design of new buildings, prediction of retrofit savings, ratings, performance path code compliance and qualification for incentives. Beyond individual building applications, larger scale applications (across the stock of buildings at various scales: national, regional and state) include: codes and standards development, utility program design, regional/state planning, and technology assessments. For these sorts of applications, a set of representative buildings are typically simulated to predict performance of the entire population of buildings. Focusing on the U.S. single-family residential building stock, this paper will describe how multiple data sources for building characteristics are combined into a highly-granular database that preserves the important interdependencies of the characteristics. We will present the sampling technique used to generate a representative set of thousands (up to hundreds of thousands) of building models. We will also present results of detailed calibrations against building stock consumption data.

building stock↗
DOE OSTI2023

Commercial Building Sensors and Controls Systems: Barriers and Drivers: Preprint

Building sensors and controls systems, including building automation systems, comprise the sensor-based devices installed in buildings as well as the control and automation of those devices. Optimized sensors and controls systems could lead to 29% annual energy savings in commercial buildings and are integral to the growth of grid-interactive efficient buildings. Only 13% of small commercial buildings, however, have installed sensors and controls systems, largely because of cost barriers. To accelerate adoption, this work seeks to increase the transparency of system costs and identify specific barriers and drivers. To gather industry insights, the team reached out to building owners, vendors, and contractors and conducted 21 interviews with the goal of collecting cost data and market characteristics regarding building sensors and controls. We collected the cost data in the form of invoices and used it to develop a percentage-based cost category breakdown. The interview data were analyzed using grounded theory to identify overarching concepts such as barriers, drivers, and future directions. From this analysis, we found the primary barriers to be complex and confusing systems, lack of user skills, and financial concerns, and the primary drivers to be operational benefits, insight into operations, and remote access to data. The future directions analysis highlighted the potential technological solutions to address gaps and barriers, as well as predicted drivers to increase adoption. This greater understanding of the costs, barriers, and drivers associated with commercial building sensors and controls systems lays the groundwork for increasing system adoption, reducing energy consumption, and transforming the market.

building automation system↗
DOE OSTI2025

Building Performance Standards and Energy Code Alignment - Technical Brief

Building energy codes focus on building design, construction and renovation and have significantly increased building efficiency since the first national energy code was published in 1975. Most jurisdictions have energy codes based on ANSI/ASHRAE/IES Standard 90.1 (hereto referred to as Standard 90.1) and the International Energy Conservation Code (IECC). Compliance options available in these model energy codes include a prescriptive path, whole building performance paths – including IECC Total Building Performance (TBP), Standard 90.1 Energy Cost Budget (ECB) method and Performance Rating Method (PRM) – and system performance paths for envelope and heating, ventilation, and air-conditioning systems. Building performance standard (BPS) policies are an emerging policy tool used by jurisdictions to reduce the operational energy use or greenhouse gas (GHG) emissions of the existing commercial building stock. BPS policies vary widely between jurisdictions and are tailored to each location’s climate and energy goals. Intuitively, projects that met a recent edition of the energy code should comply with the BPS targets. However, some new buildings may struggle with meeting the BPS for the following reasons: 1. Energy codes focus on the design of the building and its projected ability to perform efficiently, while BPS compliance is dependent on the actual ongoing performance of the building, considering variables like occupancy, operation, and maintenance. 2. There are significant differences in the methodologies used to determine BPS compliance versus code compliance, including how each handles compliance metrics, handling of building amenities, and renewable energy generation. 3. The prescriptive compliance path in the energy code is based on performance of individual building components, as opposed to the performance compliance path which accounts for holistic building design strategies and interdependent building systems. This can result in a significant variability in post-occupancy performance for buildings built using the prescriptive path. Designs on the lower end of the permitted efficiency range may struggle with meeting the BPS.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Evaluation of the Indoor Air Quality Procedure for Use in Retail Buildings

California's building efficiency standards (Title 24) mandate minimum prescribed ventilation rates (VRs) for commercial buildings. Title 24 standards currently include a prescriptive procedure similar to ASHRAE’s prescriptive “ventilation rate procedure”, but does not include an alternative procedure, akin to ASHRAE’s non-prescriptive “indoor air quality procedure” (IAQP). The IAQP determines minimum VRs based on objectively and subjectively evaluated indoor air quality (IAQ). The first primary goal of this study was to determine, in a set of California retail stores, the adequacy of Title 24 VRs and observed current measured VRs in providing the level of IAQ specified through an IAQP process, The second primary goal was to evaluate whether several VRs implemented experimentally in a big box store would achieve adequate IAQ, assessed objectively and subjectively. For the first goal, a list of contaminants of concern (CoCs) and reference exposure levels (RELs) were selected for evaluating IAQ. Ventilation rates and indoor and outdoor CoC concentrations were measured in 13 stores, including one “big box” store. Mass balance models were employed to calculate indoor contaminant source strengths for CoCs in each store. Using these source strengths and typical outdoor air contaminant concentrations, mass balance models were again used to calculate for each store the “IAQP” VR that would maintain indoor CoC concentrations below selected RELs. These IAQP VRs were compared to the observed VRs and to the Title 24- prescribed VRs. For the second goal, a VR intervention study was performed in the big box store to determine how objectively assessed indoor contaminant levels and subjectively assessed IAQ varied with VR. The three intervention study VRs included an approximation of the store’s current VR [0.24 air changes per hour (ACH)], the Title 24-prescribed VR [0.69 ACH], and the calculated IAQPbased VR [1.51 ACH]). Calculations of IAQP-based VRs showed that for the big box store and 11 of the 12 other stores, neither current measured VRs nor the Title 24-prescribed VRs would be sufficient to maintain indoor concentrations of all CoCs below RELs. In the intervention study, with the IAQP-based VR applied in the big box store, all CoCs were controlled below RELs (within margins of error). Also, at all three VRs in this store, the percentage of subjects reporting acceptable air quality exceeded an 80% criterion of acceptability. The IAQP allows consideration of outdoor air ventilation as just one of several possible tools for achieving adequate IAQ. In two of the 13 surveyed buildings, applying the IAQP to allow lower VRs could have saved energy whilst still maintaining acceptable indoor air quality. In the remaining 11 buildings, saving energy through lower VRs would require combination with other strategies, either reducing indoor sources of CoCs such as formaldehyde, or use of gas phase air cleaning technologies. Based on the findings from applying the IAQP calculations to retail stores and the IAQP-based intervention study, recommendations are made regarding the potential introduction of a comparable procedure in Title 24.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Quantifying the Financial Benefits of Multifamily Retrofits

Increasing the adoption of energy efficient building practices will require the energy sector to increase their understanding of the way that retrofits affect multifamily financial performance as well as how those indicators are interpreted by the lending and appraisal industries. This project analyzed building, energy, and financial program data as well as other public and private data to examine the relationship between energy efficiency retrofits and financial performance on three levels: building, city, and community. The project goals were to increase the data and analysis in the growing body of multifamily financial benefits work as well provide a framework for other geographies to produce similar characterization. The goals are accomplished through three tasks. Task one: A pre- and post-retrofit analysis of thirteen Chicago multifamily buildings. Task two: A comparison of Chicago income and expenses to two national datasets. Task three: An in-depth look at multifamily market sales data and the subsequent impact of buildings that undergo retrofits.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Technology Prioritization: Transforming the U.S. Building Stock to Embrace Energy Efficiency

The U.S. Buildings sector is responsible for about 40% of the national energy expenditures. This is due in part to wasteful use of resources and limited considerations made for energy efficiency during the design and retrofit phases. Recent studies have indicated the potential for up to 30-50% energy savings in the U.S. buildings sector using currently available technologies. This paper discusses efforts to accelerate the transformation in the U.S. building energy efficiency sector using a new technology prioritization framework. The underlying analysis examines building energy use micro segments using the Energy Information Administration Annual Energy Outlook and other publically available information. The tool includes a stock-and-flow model to track stock vintage and efficiency levels with time. The tool can be used to investigate energy efficiency measures under a variety of scenarios and has a built-in energy accounting framework to prevent double counting of energy savings within any given portfolio. This tool is developed to inform decision making and estimate long term potential energy savings for different market adoption scenarios.

energy efficiency↗
DOE OSTI2021

A review of machine learning in building load prediction

The surge of machine learning in recent years has been empowering engineer modeling in various fields. The decreasing hardware cost, increasing data accessibility, and advances of building automation system (BAS) allow the collection and storage of a significant amount of building operation data. The two facts provide great opportunities of applying machine learning to building energy systems modeling and analysis. There are a great number of research papers on this topic but there lacks a comprehensive and general review to summarize the current development, limitations, gaps and future trend. In this review paper series, machine learning techniques in building energy system modeling and analysis are reviewed under the organization and logic of the machine learning definition by Tom M. Mitchell: a computer program is said to learn from experience E with respect to some class of tasks T and performance measure P if its performance at tasks in T, as measured by P, improves with experience E. This paper is the first part of the review paper series, which focuses on building load prediction. First, the applications of building load prediction model (task T) are reviewed. Then, the modeling algorithms improving machine learning performance and accuracy (performance P) are reviewed. At the same time, the literature on the data perspective for modeling (experience E), including data engineering from sensors level to data level, pre-processing, feature extraction and selection, is reviewed. Finally, what is well-studied and what is lacking but with great potential are concluded; the gaps between present and future utilization of machine learning techniques are identified; the future trend and development are also predicted. The target readers of this paper are not only researchers from the building side who can get exposed to cutting edge machine learning tools, but also those from machine learning side who can understand the potential and challenge to apply machine learning in buildings.

Liang, Zhang↗
DOE OSTI2016

A Perspective of Energy Codes and Regulations for the Buildings of the Future

Today’s building energy codes focus on prescriptive requirements for features of buildings that are directly controlled by the design and construction teams and verifiable by municipal inspectors. Although these code requirements have had a significant impact, they fail to influence a large slice of the building energy use pie – including not only miscellaneous plug loads, cooking equipment and commercial/industrial processes, but the maintenance and optimization of the code-mandated systems as well. Currently, code compliance is verified only through the end of construction, and there are no limits or consequences for the actual energy use in an occupied building. In the future, our suite of energy regulations will likely expand to include building efficiency, energy use or carbon emission budgets over their full life cycle. Intelligent building systems, extensive renewable energy, and a transition from fossil fuel to electric heating systems will likely be required to meet ultra-low-energy targets. This paper lays out the authors’ perspectives on how buildings may evolve over the course of the 21st century and the roles that codes and regulations will play in shaping those buildings of the future.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Revisit of Energy Use and Technologies of High Performance Buildings

Energy consumed by buildings accounts for one third of the world?s total primary energy use. Associated with the conscious of energy savings in buildings, High Performance Buildings (HPBs) has surged across the world, with wide promotion and adoption of various performance rating and certification systems. It is valuable to look into the actual energy performance of HPBs and to understand their influencing factors. To shed some light on this topic, this paper conducted a series of portfolio analysis based on a database of 51 high performance office buildings across the world. Analyses showed that the actual site Energy Use Intensity (EUI) of the 51 buildings varied by a factor of up to 11, indicating a large scale of variation of the actual energy performance of the current HPBs. Further analysis of the correlation between EUI and climate elucidated ubiquitous phenomenon of EUI scatter throughout all climate zones, implying that the weather is not a decisive factor, although important, for the actual energy consumption of an individual building. On the building size via EUI, analysis disclosed that smaller buildings have a tendency to achieving lower energy use. Even so, the correlation is not absolute since some large buildings demonstrated low energy use while some small buildings performed opposite. Concerning the technologies, statistics indicated that the application of some technologies had correlations with some specific building size and climate characteristic. However, it was still hard to pinpoint a set of technologies which was directly correlative with a group of low EUI buildings. It is concluded that no a single factor essentially determines the actual energy performance of HPBs. To deliver energy-efficient buildings, an integrated design taking account of climate, technology, occupant behavior as well as operation and maintenance should be implemented.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Transactive Home Energy Management Systems: The Impact of Their Proliferation on the Electric Grid

Approximately 100 million singlefamily homes in the United States account for 36% of the electricity load, and often they determine the peak system load, especially on hot summer days when residential air-conditioning use is high. Traditional building power profiles are changing. Currently, there is an increased use of energy-efficient building materials and designs, which decreases building loads. In addition, there is an increased adoption of rooftop solar photovoltaic (PV), which leads to bidirectional power flow and significant power ramps as PV output decreases in the late afternoon. Building power profiles are likely to change even more as residential energy storage products proliferate. Therefore, a better understanding of residential electricity demand is key to addressing the envisioned transition of the electric power system from its traditional structure to one that is transactive.

25 ENERGY STORAGE↗
DOE OSTI2012

Net-Zero Energy Building Operator Training Program (NZEBOT)

The primary objective of the Net-Zero Energy Building Operator Training Program (NZEBOT) was to develop certificate level training programs for commercial building owners, managers and operators, principally in the areas of energy / sustainability management. The expected outcome of the project was a multi-faceted mechanism for developing the skill-based competency of building operators, owners, architects/engineers, construction professionals, tenants, brokers and other interested groups in energy efficient building technologies and best practices. The training program draws heavily on DOE supported and developed materials available in the existing literature, as well as existing, modified, and newly developed curricula from the Department of Engineering Technology & Construction Management (ETCM) at the University of North Carolina at Charlotte (UNC-Charlotte).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Technical Feasibility Study for Zero Energy K-12 Schools

This technical feasibility study provides documentation and research results supporting a possible set of strategies to achieve source zero energy K-12 school buildings as defined by the U.S. Department of Energy (DOE) zero energy building (ZEB) definition (DOE 2015a). Under this definition, a ZEB is an energy-efficient building in which, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

ANSI/ASHRAE/IES Standard 90.1-2010 Final Determination Quantitative Analysis

The U.S. Department of Energy (DOE) conducted a final quantitative analysis to assess whether buildings constructed according to the requirements of the American National Standards Institute (ANSI)/American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)/Illuminating Engineering Society of North America (IESNA) Standard 90.1-2010 (ASHRAE Standard 90.1-2010, Standard 90.1-2010, or 2010 edition) would result in energy savings compared with buildings constructed to ANSI/ASHRAE/IESNA Standard 90.1-2007(ASHRAE Standard 90.1-2007, Standard 90.1-2007, or 2007 edition). The final analysis considered each of the 109 addenda to ASHRAE Standard 90.1-2007 that were included in ASHRAE Standard 90.1-2010. All 109 addenda processed by ASHRAE in the creation of Standard 90.1-2010 from Standard 90.1-2007 were reviewed by DOE, and their combined impact on a suite of 16 building prototype models in 15 ASHRAE climate zones was considered. Most addenda were deemed to have little quantifiable impact on building efficiency for the purpose of DOE's final determination. However, out of the 109 addenda, 34 were preliminarily determined to have a measureable and quantifiable impact. A suite of 240 computer energy simulations for building prototypes complying with ASHRAE 90.1-2007 was developed. These prototypes were then modified in accordance with these 34 addenda to create a second suite of corresponding building simulations reflecting the same buildings compliant with Standard 90.1-2010. The building simulations were conducted using the DOE EnergyPlus building simulation software. The resulting energy use from the complete suite of 480 simulation runs was then converted to energy use intensity (EUI, or energy use per unit floor area) metrics (Site EUI, Primary EUI, and energy cost intensity [ECI]) results for each simulation. For each edition of the standard, these EUIs were then aggregated to a national basis for each prototype using weighting factors based on construction floor area developed for each of the 15 U.S. climate zones using commercial construction data. When compared, the resulting weighted EUIs indicated that each of the 16 building prototypes used less energy under Standard 90.1-2010 than under Standard 90.1-2007 on a national basis when considering site energy, primary energy, or energy cost. The EUIs were also aggregated across building types to a national commercial building basis using the same weighting data. On a national basis, the final quantitative analysis estimated a floor-space-weighted national average reduction in new building energy consumption of 18.2 percent for source energy and 18.5 percent when considering site energy. An 18.2 percent savings in energy cost, based on national average commercial energy costs for electricity and natural gas, was also estimated.

03 NATURAL GAS↗
DOE OSTI2010

From Tragedy to Triumph: Rebuilding Greensburg, Kansas To Be a 100% Renewable Energy City; Preprint

On May 4, 2007, Greensburg, Kansas, was hit by a 1.7-mile wide tornado with 200 mph-plus wind speeds. This tornado destroyed or severely damaged 90% of Greensburg?s structures. We discuss the progress made in rebuilding Greensburg, with a focus on the built environment and on meeting Greensburg?s goal of 100% renewable energy, 100% of the time. We also discuss key disaster recovery efforts thatenabled Greensburg to reach this goal. Key strategies included a Sustainable Comprehensive Master Plan, an ordinance resolving that city-owned buildings achieve LEED Platinum and 42% energy savings, a strong focus on rebuilding 'right' with an integrated design process, attracting significant and sustained technical experts and national media attention, and linking renewable and energyefficiency technologies to business development. After three years, more than half the homes that have been rebuilt are rated at an average of 40% energy savings. All significant commercial buildings, including the school, hospital, banks, courthouse, and retail buildings, have been rebuilt to LEED Gold and Platinum standards and exceed 40% savings, with many exceeding 50% savings. Greensburgrecently constructed a 12.5-MW community wind farm to provide all the remaining energy needed for its energy-efficient buildings and homes.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS2010

Low Mass Printable Devices for Energy Capture, Storage, and Use

The energy-efficient, environmentally friendly technology that will be presented is the result of a Space Act Agreement between NthDegree Technologies Worldwide, Inc., and the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC). The work combines semiconductor and printing technologies to advance lightweight electronic and photonic devices having excellent potential for commercial and exploration applications. Device development involves three projects that relate to energy generation and consumption: (1) a low-mass efficient (low power, low heat emission) micro light-emitting diode (LED) area lighting device; (2) a low-mass omni-directional efficient photovoltaic (PV) device with significantly improved energy capture; and (3) a new approach to building super-capacitors. These three technologies, energy capture, storage, and usage (e.g., lighting), represent a systematic approach for building efficient local micro-grids that are commercially feasible; furthermore, these same technologies, appropriately replacing lighting with lightweight power generation, will be useful for enabling inner planetary missions using smaller launch vehicles and to facilitate surface operations during lunar and planetary surface missions. The PV device model is a two sphere, light trapped sheet approximately 2-mm thick. The model suggests a significant improvement over current thin film systems. For lighting applications, all three technology components are printable in-line by printing sequential layers on a standard screen or flexographic direct impact press using the three-dimensional printing technique (3DFM) patented by NthDegree. One primary contribution to this work in the near term by the MSFC is to test the robustness of prototype devices in the harsh environments that prevail in space and on the lunar surface. It is anticipated that this composite device, of which the lighting component has passed off-gassing testing, will function appropriately in such environments consistent with NASA s exploration missions. Advanced technologies such as this show promise for both space flight and terrestrial applications.

Frazier, Donald O.↗
NASA NTRS2010

Low Mass Printable Devices for Energy Capture, Storage, and Use for Space Exploration Missions

The energy-efficient, environmentally friendly technology that will be presented is the result of a Space Act Agreement between -Technologies Worldwide, Inc., and the National Aeronautics and Space Administration s (NASA s) Marshall Space Flight Center (MSFC). This work combines semiconductor and printing technologies to advance lightweight electronic and photonic devices having excellent potential for commercial and exploration applications, and is an example of industry and government cooperation that leads to novel inventions. Device development involves three energy generation and consumption projects: 1) a low mass efficient (low power, low heat emission) micro light-emitting diode (LED) area lighting device; 2) a low-mass omni-directional efficient photovoltaic (PV) device with significantly improved energy capture; and 3) a new approach to building supercapacitors. These three technologies - energy capture, storage, and usage (e.g., lighting) - represent a systematic approach for building efficient local micro-grids that are commercially feasible; furthermore, these same technologies will be useful for lightweight power generation that enables inner planetary missions using smaller launch vehicles and facilitates surface operations. The PV device model is a two-sphere, light-trapped sheet approximately 2-mm thick. The model suggests a significant improvement over current thin film systems. All three components may be printed in line by printing sequential layers on a standard screen or flexographic direct impact press using the threedimensional printing technique (3DFM) patented by NthDegree. MSFC is testing the robustness of prototype devices in the harsh space and lunar surface environments, and available results will be reported. Unlike many traditional light sources, this device does not contain toxic compounds, and the LED component has passed stringent off-gassing tests required for potential manifesting on spacecraft such as the International Space Station. Future exploration missions will benefit from "green" technology lighting devices such as this, which show great promise for both terrestrial use and space missions.

Frazier, Donald O.↗