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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
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Miscellaneous Electric Loads: Characterization and Energy Savings Potential

Over time, miscellaneous electric loads (MELs) are expected to increase both in magnitude and share of residential and commercial building energy consumption. This trend is most apparent in North America, but it is also occurring in Japan and Europe. However, the contribution of MELs to building energy use is not currently well understood, both because the products in this category are transforming rapidly and the definition and classification of MELs is ambiguous. This study estimated the national energy consumption of 36 MELs using best-available data and found them to comprise 12% of delivered electricity to the U.S. residential and commercial building sectors. If 26 of these MELs were replaced with the most energy-efficient product models available on the market, their energy consumption could be halved to 6% of delivered electricity. National energy models will better account for building energy consumption by incorporating the MELs data collected and analyzed for this study, leading to improved policy decisions.

Miscellaneous electric loads, Plug loads, Taxonomy↗
DOE OSTI2022

International Actions to Reduce Miscellaneous Electrical Loads Energy Consumption

Miscellaneous electric loads (MELs) research dates back over thirty years, with the earliest publications on MELs originating in the late 1980s. As the number and types of MELs grew over the subsequent decades, so did the body of minimum energy performance standards (MEPS) and regulations put in place to control what is now an ever-growing source of energy consumption in the residential and commercial sectors. In particular, these MEPS are designed to control off-mode, standby, and connected standby power consumption to prevent energy waste. Research on MELs focuses a great deal on analyzing the characteristics of MELs, approaches for measuring their consumption, and at a higher level what constitutes a MEL. Despite these advances, there has yet to be a comparison of different approaches across regulatory bodies of MELs – both between and within countries – to identify similarities, gaps, and opportunities for crafting common language and testing procedures. This study provides an international analysis of MELs-related voluntary and mandatory MEPS across 12 economies to address this gap. The analysis demonstrates that even while economies may participate in shared commitments to regulated MELs energy consumption, there remains no common language for framing MELs, nor is there a shared understanding of updating aging test procedures used globally for verifying MELs-related MEPS.

Miscellaneous Electric Loads, MELs, Appliance and ↗
DOE OSTI2022

International Actions to Reduce Miscellaneous Electrical Loads Energy Consumption

Miscellaneous electric loads (MELs) research dates back over 30 years, with the earliest publications about MELs originating in the late 1980s. As the number and types of MELs have grown during the intervening decades, so has the body of minimum energy performance standards (MEPS) and regulations put in place to control what is now a significant energy end use in the residential and commercial sectors. In particular, these MEPS are designed to control off-mode, standby, and connected standby power consumption to prevent energy waste. Research on MELs focuses a great deal on analyzing the characteristics of MELs, approaches for measuring their consumption, and at a higher level what constitutes a MEL. Despite these advances, there have been few comparisons of different approaches to curtail MELs energy consumption across regulatory bodies of MELs—both between and within countries—to identify similarities, gaps, and opportunities for crafting common language and standards. This study provides an analysis of international MELs-related voluntary and mandatory MEPSs across 12 economies to address this gap. The analysis demonstrates that although economies may share the commitment to regulate the energy consumption of MELs, there still is no common language for framing MELs, nor is there a shared understanding for harmonizing MEPS for MELs.

Butzbaugh, Josh↗
DOE OSTI2025

Cross-cutting strategies to lower electricity use of miscellaneous electric loads in the domestic sector

Miscellaneous Electric Loads (MELs) account for roughly one quarter of building electricity use in most developed countries. A product-specific approach to lowering MELs electricity use in this category takes too long and costs too much because there are so many MELs, each providing unique services. An alternative approach focusing on key functionalities was therefore explored. These functionalities include: (1) power management, (2) power scaling, and (3) power conversion. Cross-cutting efficiency improvements to these functionalities can be incorporated into broad categories of MELs, thus saving electricity and lowering costs. Even though the population of MELs is diverse and rapidly evolving, major technical opportunities exist to improve their efficiency in these functionalities. Research into energy-saving solutions within the cross-cutting technologies will probably have larger savings than focusing on single products.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Improving Energy Efficiency of Wireless Communication Circuitry in Miscellaneous Electric Loads (Final Report)

The overarching objective of this project is to reduce phantom power in miscellaneous electric loads (MELs). We achieve this power reduction with a wireless Connectivity Module that uses ultra-low power (ULP) custom wakeup receivers (WRXs) paired with an ULP node controller (NC) chip. These components can remain always-on at power levels much lower than the inherent standby power of MELs, allowing them to cut off the phantom power to the MELs device while still preserving responsiveness of the MELs devices with low latency when they are needed, either via a wireless wakeup signal received by the WRX or a prediction that the device is needed based on a model.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Emerging Zero-Standby Solutions for Miscellaneous Electric Loads and the Internet of Things

Despite technical advances in efficiency, devices in standby continue to consume up to 16% of residential electricity. Finding practical, cost-effective reductions is difficult. While the per-unit power consumption has fallen, the number of units continuously drawing power continues to grow. This work reviews a family of technologies that can eliminate standby consumption in many types of electrical plug loads. It also investigates several solutions in detail and develops prototypes. First, burst mode and sleep transistors are established as building blocks for zero-standby solutions. This work then studies the application of two types of wake-up signals. The first is from an optical transmission, and is applicable to remote-controlled devices with a line-of-sight activation, such as set-top boxes, ceiling fans, and motorized curtains. The second is from a wake-up radio, and is applicable to any wireless products. No single technology will address all standby power situations; however, these emerging solutions appear to have broad applicability to save standby energy in miscellaneous plug loads.

42 ENGINEERING↗
DOE OSTI2019

Data fusion in predicting internal heat gains for office buildings through a deep learning approach

Heating, Ventilation, and Air Conditioning (HVAC) is a major energy consumer in buildings. The predictive control has demonstrated a potential to reduce HVAC energy use. To facilitate predictive HVAC control, internal heat gains prediction is required. Here, we applied Long Short-Term Memory Networks, a special form of deep neural network, to predict miscellaneous electric loads, lighting loads, occupant counts and internal heat gains in two United States office buildings. Compared with the predetermined schedules used in American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standard 90.1, the Long Short-Term Memory Networks method could reduce the prediction errors of internal heat gains from 12% to 8% in Building A, and from 26% to 16% in Building B. It was also found that for internal heat gains prediction, miscellaneous electric loads is a more important feature than occupant counts for two reasons. First, miscellaneous electric loads is the best proxy variable for internal heat gains, as it is the major component of and has the highest correlation coefficient with the internal heat gains. Second, miscellaneous electric loads contain valuable information to predict occupant count, while occupant count could not help improve miscellaneous electric loads prediction. Lastly, these findings could help researchers and practitioners select the most relevant features to more accurately predict internal heat gains for the implementation of predictive HVAC control in buildings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Study Highlights: Characterizing Plug Load Energy Use and Savings Potential in Army Buildings

A recent study of plug load devices in Army buildings has identified opportunities to save over 83 million kWh of electricity valued at over $5 million per year. These savings may be conservative and were identified by inventorying and monitoring plug load and miscellaneous electric load (MEL) equipment within representative Army buildings. The objective was to better understand the energy consumed by these devices and identify approaches for reducing it while enhancing resilience. This summary highlights the findings, lessons learned, and recommendations identified by the study.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Characterizing Plug Load Energy Use and Savings Potential in Army Buildings

The Assistant Secretary of the Army (Installations, Energy and Environment) tasked the Pacific Northwest National Laboratory to examine plug loads in typical Army buildings. Plug loads (also known as miscellaneous electric loads (MELs)) represent the electricity used by appliances and devices that are plugged in or hardwired and serve functions outside of a building’s core end uses. Common plug loads include computers, printers, copiers, networking devices, refrigerators, and vending machines. They also include personal electronic devices such as televisions, smart phones, tablets, and gaming systems. Examples of hardwired MELs include elevators, air compressors, and fire and security systems. The findings from this study confirm that significant energy is consumed within Army buildings by plug load devices and hardwired MEL equipment. A number of opportunities are identified for reducing unnecessary energy use that could save the Army over $5 million per year when broadly applied. Army regulations clearly spell out expectations for the purchase and operation of information technology equipment (computers, laptops, monitors, printers, and multi-function devices). However, the policies regarding the shutdown or activation of sleep and other lower power modes after 30 minutes of inactivity (15 minutes for monitors) do not appear to be consistently followed. There are many effective approaches and pathways for impacting change as it relates to improving awareness, implementing measures, and adjusting behaviors to identify and reduce plug load energy use. The Army should prioritize and consider deploying all of these to better understand and manage plug load equipment to save energy and enhance resilience across their facilities. Engaging the building occupants who use these devices daily via outreach and education should be a strong component of the strategy. The focus should be on reducing waste without sacrificing productivity or the benefits that many of these devices provide. Continued evaluation of plug loads beyond that performed here is important to gather lessons from additional building and equipment types, and to stay aware of evolving device technology and management options. This will highlight additional needs for policies, best practices, control technologies, and education of personnel to achieve real reductions in energy waste from plug load equipment. It is recommended that this study may serve as the foundation for a broader and sustained focus on plug loads and MELs, towards simultaneously enhancing the productivity, readiness, and resilience of the Army while reducing energy use and demand, and freeing up resources to better support the mission.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Net-Zero Energy Home Grows Up: Lessons and Puzzles from 10 Years of Data; Preprint

In 2005, Habitat for Humanity of Metro Denver, with support from NREL and other partners, built one of the first homes in the US to achieve net-zero energy based on monitored data. A family of three moved into the house when it was completed and lives there still. The home has been monitored continuously for the past ten years. Although PV production has remained steady, net energy performance has varied each year. The home was a net producer of energy annually in each of the first three years and in the ninth year, but not in years four through eight. Over the years, the PV system provided between 124% and 64% of the home source energy use. Electricity use in the home increased steadily during the first eight years, even though no significant new appliance was introduced into the house, such as a window air conditioner. Miscellaneous electric loads and space heating, both strongly dependent on occupant behavior, appear to be primarily responsible for the observed increase in energy use. An interesting aspect of this case study is how, even within a single family, natural changes in occupant lifestyles over time (e.g., kids growing up, schedules changing) can substantially impact the overall energy intensity of a home. Data from the last ten years will be explored for lessons learned that can improve the way we design low-load homes without sacrificing comfort or convenience for the occupants, and how we can make realistic predictions of long-term energy performance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

A Net-Zero Energy Home Grows Up: Lessons and Puzzles from 10 Years of Data

In 2005, Habitat for Humanity of Metro Denver, with support from NREL and other partners, built one of the first homes in the US to achieve net-zero energy based on monitored data. A family of three moved into the house when it was completed and lives there still. The home has been monitored continuously for the past ten years. Although PV production has remained steady, net energy performance has varied each year. The home was a net producer of energy annually in each of the first three years and in the ninth year, but not in years four through eight. Over the years, the PV system provided between 124% and 64% of the home source energy use. Electricity use in the home increased steadily during the first eight years, even though no significant new appliance was introduced into the house, such as a window air conditioner. Miscellaneous electric loads and space heating, both strongly dependent on occupant behavior, appear to be primarily responsible for the observed increase in energy use. An interesting aspect of this case study is how, even within a single family, natural changes in occupant lifestyles over time (e.g., kids growing up, schedules changing) can substantially impact the overall energy intensity of a home. Data from the last ten years will be explored for lessons learned that can improve the way we design low-load homes without sacrificing comfort or convenience for the occupants, and how we can make realistic predictions of long-term energy performance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

AlphaBuilding - Synthetic Buildings Operation Dataset

This is a synthetic building operation dataset which includes HVAC, lighting, miscellaneous electric loads (MELs) system operating conditions, occupant counts, environmental parameters, end-use and whole-building energy consumptions at 10-minute intervals. The data is created with 1395 annual simulations using the U.S. DOE detailed medium-sized reference office building, and 30 years' historical weather data in three typical climates including Miami, San Francisco, and Chicago. Three energy efficiency levels of the building and systems are considered. Assumptions regarding occupant movements, occupants' diverse temperature preferences, lighting, and MELs are adopted to reflect realistic building operations. A semantic building metadata schema - BRICK, is used to store the building metadata. The dataset is saved in a 1.2 TB of compressed HDF5 file. This dataset can be used in various applications, including building energy and load shape benchmarking, energy model calibration, evaluation of occupant and weather variability and their influences on building performance, algorithm development and testing for thermal and energy load prediction, model predictive control, policy development for reinforcement learning based building controls.

AlphaBuilding↗
DOE OSTI2021

Endpoint Use Efficiency Comparison for AC and DC Power Distribution in Commercial Buildings

Advances in power electronics and their use in Miscellaneous Electric Loads (MELs) in buildings have resulted in increased interest in using low-voltage direct current (DC) power distribution as a replacement for the standard alternating current (AC) power distribution in buildings. Both systems require an endpoint converter to convert the distribution system voltage to the MELs voltage requirements. This study focused on the efficiency of these endpoint converters by testing pairs of AC/DC and DC/DC power converters powering the same load profile. In contrast to prior studies, which estimated losses based on data sheet efficiency and rated loads, in this study, we used part load data derived from real-world time-series load measurements of MELs and experimentally characterized efficiency curves for all converters. The measurements performed for this study showed no systematic efficiency advantage for commercially available DC/DC endpoint converters relative to comparable, commercially available AC/DC endpoint converters. For the eight appliances analyzed with the pair of converters tested, in 50%, the weighted energy efficiency of the DC/DC converter was higher, while, for the other 50%, the AC/DC converter was. Additionally, the measurements indicated that the common assumption of using either data sheet efficiency values or efficiency at full load may result in substantial mis-estimates of the system efficiency.

AC/DC converters↗
DOE OSTI2019

Harvesting from Ambient Energy: Designing Enabling Technologies for Sustainable Buildings

Electricity consumption in the commercial sector is forecasted to increase by 0.5% on an annual bases between 2017 to 2050. This is despite best design practices and adoption of more energy efficient resources for buildings. This increase is prevalent in miscellaneous electrical loads that studies have shown if their usage is tracked and conveyed to the occupant will result in up 34% consumption reduction. Diverse tools and research methodologies are being developed to track their location. This paper addresses one such method to identify the location of energy at the point of use using energy harvesting. The paper proposes a design process for magnetic flux harvesting around current carrying conductors of the electrical system in buildings for the purpose of powering sensors and/or for use as a triggering signal for energy consumption location in the built environment. Building on the electromagnetic induction theory, a relationship is developed between the size of the harvesting device and the total energy output. A prototype energy harvesting device based on the proposed data is built and tested through laboratory experiments.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Energy use of residential safety, security, and health devices

Miscellaneous electrical loads (MELs) are responsible for a significant fraction of energy consumption in buildings. This paper addresses one category of MELs: Safety, Security, and Health Devices (SSHDs). Common SSHDs include: electrical life safety equipment, smoke alarms, radon mitigation fans, and home oxygen concentrators. The installation or use of these devices is dictated by building codes, health providers, insurance companies, and other entities—none of which would ordinarily consider energy efficiency a priority. For this project, the most important residential devices were explored in terms of their governing regulations, functions, technologies, and energy use. The power consumption of 41 life safety SSHDs were measured. Individual power consumption of life safety devices is very small but many are typically required in every home. Devices performing the same functions have wide ranges in power use. Opportunities for reducing SSHD energy use were investigated, the results are summarized, and recommendations are made for further actions that could be taken to reduce SSHD energy use. Finally, SSHDs identified in this paper are responsible for at least one percent of current U.S. residential electricity consumption, but that number will climb steadily as existing buildings are upgraded and new types of SSHDs appear.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Load-Packaged AC/DC and DC/DC Power Electronics Converter Performance Data

This data set contains experimentally characterized performance data from load-packaged alternating current to direct current (AC/DC) and direct current to direct current (DC/DC) power electronics converters associated with lighting devices and miscellaneous electrical loads typically found in commercial buildings in the United States. The data set contains input power, output power, efficiency, and harmonic spectrum data for 58 AC/DC converters and 35 DC/DC converters.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Harmonic cancellation within AC low voltage distribution for a realistic office environment

An increase of non-linear loads, primarily from power electronics, has substantially increased current harmonics in commercial buildings, which contributes to decreased transformer efficiency / lifespan and poor power quality. This study uses recorded power consumption data from common miscellaneous electric loads (MELs) seen in offices, combined with detailed characterizations of example MELs, to simulate harmonic cancellation within building circuits. Typically, harmonic cancellation studies assume that AC converters operate across their rated power range. However, this study finds that common MELs operate below 40% of rated power the majority of the time when not quiescent; 89% of sampled devices never operated above 60% of rated power. Simulations using these more realistic power levels indicate current-harmonic cancellation (3rd to 13th harmonic) is significantly lower than that predicted when using full-range power assumptions, resulting in minor errors for low-order harmonics and larger errors for higher order harmonics. Furthermore, increased MELs load diversity increases harmonic cancellation, but insufficiently to eliminate errors. In contrast, blending lighting loads with MELs on the secondaries of distribution transformers improves harmonic cancellation to near those predicted by traditional methods. These results indicate that realistic power levels, as well as better characterization of harmonics from typical MELs, should be used to estimate harmonic cancellation.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

A synthetic building operation dataset

Abstract This paper presents a synthetic building operation dataset which includes HVAC, lighting, miscellaneous electric loads (MELs) system operating conditions, occupant counts, environmental parameters, end-use and whole-building energy consumptions at 10-minute intervals. The data is created with 1395 annual simulations using the U.S. DOE detailed medium-sized reference office building, and 30 years’ historical weather data in three typical climates including Miami, San Francisco, and Chicago. Three energy efficiency levels of the building and systems are considered. Assumptions regarding occupant movements, occupants’ diverse temperature preferences, lighting, and MELs are adopted to reflect realistic building operations. A semantic building metadata schema - BRICK, is used to store the building metadata. The dataset is saved in a 1.2 TB of compressed HDF5 file. This dataset can be used in various applications, including building energy and load shape benchmarking, energy model calibration, evaluation of occupant and weather variability and their influences on building performance, algorithm development and testing for thermal and energy load prediction, model predictive control, policy development for reinforcement learning based building controls.

24 POWER TRANSMISSION AND DISTRIBUTION↗