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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Performance Simulation and Analysis of Occupancy-Based Control for Office Buildings with Variable-Air-Volume Systems

Variable-air-volume (VAV) systems are used in many office buildings. The minimum airflow rate setting of VAV terminal boxes has a significant impact on both energy consumption and indoor air quality. Conventional controls usually have the terminal’s minimum airflow rate at a constant (e.g., 30% or more of the terminal design airflow rate), irrespective of the occupancy status, which may cause problems, such as excessive simultaneous heating and cooling, under ventilation, and thermal comfort issues. This paper examines the potential of energy savings from occupancy-based controls (OBCs). The sensed occupancy information, either occupant presence or people count, is used to determine the airflow rate of terminal boxes, the thermostat setpoints, and the lighting control. Using EnergyPlus, a whole-building energy modeling software, the energy savings of OBC strategies are evaluated for representative existing medium office buildings in the U.S. The simulation results show that the conventional OBC, based on occupant presence sensing, can save 8% of whole-building energy use in Miami (hot climate) for systems without air-side economizer and about 13% in both Baltimore (mixed climate) and Chicago (cold climate). Comparatively, the advanced OBC, based on people counting, can save 8% in Miami to 23% in Baltimore for systems with economizers. The outdoor-air fraction of the supply air from air-handling units significantly affects the potential energy savings from the advanced OBC strategy. In addition to energy savings, the advanced OBC satisfies the zone ventilation during all occupied hours over the whole year.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Co-Simulation of Electric Power Distribution Systems and Buildings including Ultra-Fast HVAC Models and Optimal DER Control

Smart homes and virtual power plant (VPP) controls are growing fields of research with potential for improved electric power grid operation. A novel testbed for the co-simulation of electric power distribution systems and distributed energy resources (DERs) is employed to evaluate VPP scenarios and propose an optimization procedure. DERs of specific interest include behind-the-meter (BTM) solar photovoltaic (PV) systems as well as heating, ventilation, and air-conditioning (HVAC) systems. The simulation of HVAC systems is enabled by a machine learning procedure that produces ultra-fast models for electric power and indoor temperature of associated buildings that are up to 133 times faster than typical white-box implementations. Hundreds of these models, each with different properties, are randomly populated into a modified IEEE 123-bus test system to represent a typical U.S. community. Advanced VPP controls are developed based on the Consumer Technology Association (CTA) 2045 standard to leverage HVAC systems as generalized energy storage (GES) such that BTM solar PV is better utilized locally and occurrences of distribution system power peaks are reduced, while also maintaining occupant thermal comfort. An optimization is performed to determine the best control settings for targeted peak power and total daily energy increase minimization with example peak load reductions of 25+%.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1973

A study of the thermoregulatory characteristics of a liquid-cooled garment with automatic temperature control based on sweat rate: Experimental investigation and biothermal man-model development

Experimental results for three subjects walking on a treadmill at exercise rates of up to 590 watts showed that thermal comfort could be maintained in a liquid cooled garment by using an automatic temperature controller based on sweat rate. The addition of head- and neck-cooling to an Apollo type liquid cooled garment increased its effectiveness and resulted in greater subjective comfort. The biothermal model of man developed in the second portion of the study utilized heat rates and exchange coefficients based on the experimental data, and included the cooling provisions of a liquid-cooled garment with automatic temperature control based on sweat rate. Simulation results were good approximations of the experimental results.

Chambers, A. B.↗
NASA NTRS1974

Design and performance of Skylab thermal/environmental control system

The function of the thermal/environmental control systems was to provide a comfortable thermal environment for the crew, to cool electronic components, to supply a controlled oxygen/nitrogen atmosphere, and to remove moisture, carbon dioxide, odors, and trace contaminants from the atmosphere. A separate refrigeration system was used to chill and freeze food and biomedical samples and to provide cold water for drinking. This paper describes system design and compares in-flight performance to preflight predictions. A discussion of in-flight anomalies and corrective actions is also included.

Hopson, G. D.↗
NASA NTRS1975

Environmental factors

The selection of an Apollo spacecraft atmosphere was based on the establishment of an acceptable range of atmospheric composition and pressure, the establishment of acceptable carbon dioxide levels, thermal comfort criteria, and acceleration and impact limits. The prime design requirements in a spacecraft system are minimum weight, volume, power usage, reliability, ease of maintenance, environmental compatibility, integration with other systems, and crew compatibility. The selection considerations are reviewed.

E.L.Michel↗
NASA NTRS1975

Thermal exchanges and temperature stress

Thermal comfort during space flight is discussed. Heat production of man during space flight and wear loss as a mean of dissipating heat are described. Water cooled garments are also considered, along with tolerance for extreme heat and body heat storage. Models of human temperature regulation are presented in the form of documented FORTRAN programs.

Webb, P.↗
NASA NTRS1976

Control of thermal balance by a liquid circulating garment based on a mathematical representation of the human thermoregulatory system

Test data and a mathematical model of the human thermoregulatory system were used to investigate control of thermal balance by means of a liquid circulating garment (LCG). The test data were derived from five series of experiments in which environmental and metabolic conditions were varied parametrically as a function of several independent variables, including LCG flowrate, LCG inlet temperature, net environmental heat exchange, surrounding gas ventilation rate, ambient pressure, metabolic rate, and subjective/obligatory cooling control. The resultant data were used to relate skin temperature to LCG water temperature and flowrate, to assess a thermal comfort band, to demonstrate the relationship between metabolic rate and LCG heat dissipation, and so forth. The usefulness of the mathematical model as a tool for data interpretation and for generation of trends and relationships among the various physiological parameters was also investigated and verified.

Kuznetz, L. H.↗
NASA NTRS1991

Results of shuttle EMU thermal vacuum tests incorporating an infrared imaging camera data acquisition system

Manned tests in Chamber B at NASA JSC were conducted in May and June of 1990 to better quantify the Space Shuttle Extravehicular Mobility Unit's (EMU) thermal performance in the cold environmental extremes of space. Use of an infrared imaging camera with real-time video monitoring of the output significantly added to the scope, quality and interpretation of the test conduct and data acquisition. Results of this test program have been effective in the thermal certification of a new insulation configuration and the '5000 Series' glove. In addition, the acceptable thermal performance of flight garments with visually deteriorated insulation was successfully demonstrated, thereby saving significant inspection and garment replacement cost. This test program also established a new method for collecting data vital to improving crew thermal comfort in a cold environment.

Anderson, James E.↗
NASA NTRS1993

A unique exercise facility for simulating orbital extravehicular activity

A unique exercise facility has been developed and used to simulate orbital extravehicular activity (EVA). The device incorporates an arm ergometer into a mechanism which places the subject in the zero-g neutral body posture. The intent of this configuration is to elicit muscular, cardiovascular, respiratory, and thermoregulatory responses similar to those observed during orbital EVA. Experiments done with this facility will help characterize the astronaut's dynamic heat balance during EVA and will eventually lead to the development of an automated thermal control system which would more effectively maintain thermal comfort.

Williamson, Rebecca C.↗
NASA NTRS1993

Space simulation in the Neutral Buoyancy Test Facility

Various methods have been to simulate reduced gravity environments for space systems research and development. Neutral buoyancy has been the most universally used simulation of zero-g. This paper describes the facilities, personnel and experimental work that are associated with the Neutral Buoyancy Test Facility (NBTF) at NASA Ames Research Center (ARC). This facility provides a unique underwater environment for the researcher to simulate reduced gravity activities and evaluate the performances of space-related equipment. The NBTF's small size gives it several advantages over larger water facilities. Second, the facility is used for research purposes only, eliminating any scheduling conflicts with astronaut training. Lastly, the small volume of water allows the researcher to more easily vary the water temperature. This feature is ideal for investigations of astronaut thermal comfort and regulation. Recent investigations have used the NBTF for reduced gravity simulation of locomotion and load-carrying, among other interesting research endeavors.

Luna, Bernadette↗
NASA NTRS2007

Environmental Physiology at the Johnson Space Center: Past, Present, and Future

This viewgraph presentation reviews the work in environmental physiology done at Johnson Space Center (JSC). The work is aimed at keeping astronauts healthy. This is a different approach than treating the sick, and is more of an occupational health model. The reduction of risks is the main emphasis for this work. They emphasis is to reduce the risk of decompression sickness (DCS) and acute mountain sickness (AMS). The work in environmental physiology encompasses the following areas: (1) Pressure: hypobaric and hyperbaric (2) Gases: hypoxia and hyperoxia, hypercapnia--closed space issues, inert gas physiology / respiration (3) Temperature: hypothermia and hyperthermia, thermal comfort, Protective clothing diving, aviation, mountaineering, and space (4) Acceleration (5) Noise and Vibration (6) Exercise / Performance (6) Acclimatization / Adaptation: engineering solutions when necessary. This presentation reviews the work done at JSC in the areas of DCS and AMS.

Conkin, Johnny↗
NASA NTRS2009

Determination of Time Required for Materials Exposed to Oxygen to Return to Reduced Flammability

Increased material flammability due to exposure to high oxygen concentrations is a concern from both a safety and operational perspective. Localized, high oxygen concentrations can occur when exiting a higher oxygen concentration environment due to material saturation, as well as oxygen entrapment between barrier materials. Understanding of oxygen diffusion and permeation and its correlation to flammability risks can reduce the likelihood of fires while improving procedures as NASA moves to longer missions with increased extravehicular activities in both spacecraft and off-Earth habitats. This paper examines the time required for common spacecraft materials exposed to oxygen to return to reduced flammability after removal from the increased oxygen concentration environment. Specifically, NASA-STD-6001A maximum oxygen concentration testing and ASTM F-1927 permeability testing were performed on Nomex 4 HT90-40, Tiburon 5 Surgical Drape, Cotton, Extravehicular Mobility Unit (EMU) Liquid-Cooled Ventilation Garment, EMU Thermal Comfort Undergarment, EMU Mosite Foam with Spandex Covering, Advanced Crew Escape Suit (ACES) Outer Cross-section, ACES Liquid Cooled Garment (LCG), ACES O2 Hose Material, Minicel 6 Polyethylene Foam, Minicel Polyethylene Foam with Nomex Covering, Pyrell Polyurethane Foam, and Zotek 7 F-30 Foam.

Harper, Susana↗
NASA NTRS2010

Portable Life Support Subsystem Thermal Hydraulic Performance Analysis

This paper presents the current state of the thermal hydraulic modeling efforts being conducted for the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS). The goal of these efforts is to provide realistic simulations of the PLSS under various modes of operation. The PLSS thermal hydraulic model simulates the thermal, pressure, flow characteristics, and human thermal comfort related to the PLSS performance. This paper presents modeling approaches and assumptions as well as component model descriptions. Results from the models are presented that show PLSS operations at steady-state and transient conditions. Finally, conclusions and recommendations are offered that summarize results, identify PLSS design weaknesses uncovered during review of the analysis results, and propose areas for improvement to increase model fidelity and accuracy.

Barnes, Bruce↗
NASA NTRS2024

Baltimore Energy & Infrastructure: Assessing Urban Heat Vulnerability in Baltimore Neighborhoods to Inform Transportation Resiliency Planning Efforts

Across the world, climate change is altering cities and their local climate systems. Following global trends of rising mean temperatures, Baltimore, Maryland is projected to experience more frequent extreme heat events. Exacerbated by Urban Heat Island (UHI) effects, residents of the city face high temperatures from limited tree canopy, highly paved and impervious surfaces, limited air flow, and high concentrations of localized emissions. Urban heat is dispersed asymmetrically, with historically marginalized populations experiencing disproportionately severe heat. Recognizing the impacts of extreme urban heat, the Maryland Transit Administration (MTA) collaborated with us, the Spring 2024 Goddard Energy and Infrastructure NASA DEVELOP team to assess urban impacts of MTA users and assets and explore opportunities to enhance resiliency planning. We evaluated the feasibility of NASA Earth observations (EOs) in visualizing heat vulnerability in Baltimore City and County. We mapped UHI and extreme heat using remote sensing observations, tailored a Heat Priority Score (HPS) to analyze heat data in tandem with socioeconomic data from American Community Survey (ACS), and utilized SOlar and LongWave Environmental Irradiance Geometry (SOLWEIG) model to estimate MTA riders’ thermal comfort. NASA EOs served to quantify the distribution and severity of extreme heat at the block group level, which was found to correlate with a lack of vegetation and presence of densely built-up surroundings. The HPS revealed that extreme heat events most negatively impact communities that exhibit social vulnerability through indicators such as age, race, and income. These findings will inform neighborhood resiliency plans for the MTA that can be incorporated into their Adaptation Resiliency Toolbox (ART).

Baltimore,↗
NASA NTRSDate not supplied

NASA POWER: Providing Analysis-Ready, Cloud-Optimized Data for AI /ML Training and Applications in Earth Science

As global demand for sustainable development grows, the integration of Earth Observation (EO) data into decision making frameworks has become a primary objective for the scientific community. The NASA Prediction of Worldwide Energy Resources (POWER) project serves as a bridge between NASA EO data and the specialized needs of the renewable energy, sustainable infrastructure and agroclimatology communities. In this poster presentation we will present an overview of POWER data products and services along with its use in diverse research to decision-making workflows. By providing over 40 years of high-resolution historical, hourly and daily solar and meteorological data, POWER transforms satellite observations and global model reanalysis into actionable, Analysis-Ready Dataset (ARD). Currently, the project delivers over 250 industry-friendly parameters to the users from different NASA datasets like CERES SYN1Deg, MERRA-2, and IMERG alongside downscaled CMIP6 climate model data, fulfilling over 16 million requests from 50,000 unique users monthly. To ensure data quality and traceability, these parameters are rigorously validated against the ground-based observations from the Baseline Surface Radiation Network (BSRN) and the Global Surface Summary of the Day (GSOD) – these results will be discussed in the presentation. A newly introduced web-based PaRameter Uncertainty ViEwer (PRUVE) tool will be presented that provides an online validation platform to the users that benchmarks satellite-based and assimilation data products against these surface measurements. To reduce technical barriers to data adoption, POWER data is accessible through RESTful APIs, ESRI ArcGIS Image Services, a web-based Data Access Viewer tool, allowing users to visualize, validate and apply the dataset. For efficient data delivery POWER data is cloud-optimized into Zarr datastore accessible through NASA managed Amazon S3 ensures high-performance allowing users to integrate EO directly into operational pipelines. These customized services will be presented. Use cases from application will be presented from the energy sector - such as for design of generation systems, performance monitoring of solar power plants, in infrastructure sector- optimizing building energy efficiency and thermal comfort, in agriculture – such as driving crop simulation and yield forecasting models to enable climate resilient farming. Furthermore, the shift toward machine learning (ML) in EO research that has positioned POWER as a key provider for training datasets which will be discussed. Use-cases will be presented to showcase how NASA data is enabling the development of predictive tools for climate variability and resource management. The poster will present POWER’s future plans including technology development to enhance data traceability and reproducibility and improving I/O performance to support the rapid integration of new EO products, ensuring that POWER remains a robust scalable backend for the evolving landscape of AI-driven Earth Science. Additionally, POWER is developing an AI Agent and an MCP-Server to enable industry AI-Agentic workflows.

Neha Khadka↗
DOE OSTI2020

Rooftop Unit Sizing Guidance

This fact sheet explores how to correctly map building loads to rooftop unit (RTU) capacity to help minimize capital investment and ongoing operational costs while maximizing thermal comfort.

Rooftop Unit, RTU, Design Load, energy efficiency,↗
DOE OSTI2021

Application of the DNAS framework expansion to occupant population synthesis

Research in occupant behaviour is now using a more elaborate framework of building occupant interaction. Researchers often face challenges in collecting data, particularly for the data to meet the minimum number of required data points and the data interoperability requirements. Researchers address the first issue with the synthetic population and the latter with data ontologies. While synthetic population is commonly used to address the first issue, data ontology development is used to address the latter. The two solutions are complementary to each other. One of the known ontologies in building occupant behaviour research is the Drivers-Needs-Actions-Systems (DNAS) ontology, which has been used by building modelers to describe energy-related occupant behaviour. This paper describes the ontology-based synthetic population generation that can be used in the agent-based modeling (ABM) applications. This paper considers multiple data sources, including ASHRAE Thermal Comfort DB II and IEA Annex 66 data sets. A case study of an office building is used to present the workflow of DNAS framework expansion, synthetic population generation, and agent-based modeling.

Chandra Putra, Handi↗