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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

A Field and Laboratory Study to Characterize Fault Prevalence in Residential Comfort Systems

This report describes a project whose goal was to determine the prevalence of residential comfort system faults. The focus is on air conditioners and heat pumps, and on key faults that can occur during installation and have significant impacts on performance: (1) incorrect refrigerant charge level (undercharge or overcharge); (2) indoor coil airflow rate; (3) liquid line restrictions; (4) non-condensable gas in the refrigerant; and (5) duct leakage. In addition to quantifying fault prevalence, we collected metadata that could be studied to determine whether there are correlations that suggest drivers of fault prevalence, such as regional variations in practice, economic factors, climatic impacts, and others.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Human‐Skin‐Inspired Adaptive Smart Textiles Capable of Amplified Latent Heat Transfer for Thermal Comfort

Thermally adaptive textiles (TATs) enable human subjects to attain thermal comfort without energy consumption, which can lead to enormous energy savings on heating, ventilation, and air conditioning (HVAC) in buildings. Herein, TAT structures which respond to the sweat and generate pores by opening an array of flap‐shaped pores patterned on the fabric surface are proposed. A moisture‐driven self‐actuator for flap opening by constructing a bilayer consisting of a hygroscopic layer using polyethylene glycol and cellulose acetate, and a hydrophobic polymer using a polyester type polymer, is used and successfully demonstrated an essentially instant 4 °C apparent temperature cooling performance within one minute of sweat–humidity‐initiated actuation while wearing TAT using a sweating skin simulated device.

Kim, Gunwoo↗
DOE OSTI2020

A conceptual model for how to design for building envelope characteristics. Impact of thermal comfort intervals and thermal mass on commercial buildings in U.S. climates

The paper presents a simplified conceptual model for energy demand calculations based on building envelope characteristics, thermal mass and local climate. It is based on a network model and lumped analysis of the dynamic process. Characteristic parameters for the buildings are suggested; Driving temperature (DT), Driving temperature difference, (DTD), External Load Temperature (ELT), and Thermal Load Resistance (TLR). The Building Envelope Performance ( BEP 0 ), based on a controlled constant indoor temperature is introduced. Solution techniques using stable explicit forward differences based on analytical solutions are derived. The conceptual model has been used for mapping the Driving temperature difference and introduced two performance factors and . The first factor represents the effect of thermal comfort interval and thermal mass on the energy demand. The latter represents the ratio between cooling and heating energy demand. These three parameters and factors have been visualized on U.S. maps and enable a possibility to communicate the demand of energy, and cooling and the coupling to building characteristics, in a concise way.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Modeling the Impacts of Urbanization on Summer Thermal Comfort: The Role of Urban Land Use and Anthropogenic Heat

Urban land use and anthropogenic heat (AH) emission can considerably influence the human thermal comfort during extreme heat events. In this study, a spatially heterogeneous AH emission data and updated urban land use data are integrated into the Weather Research and Forecasting model to simulate the physical processes of urban warming during summer. Simulations conducted in the Yangtze River Delta (YRD) of east China suggest that the mean urban heat island intensity reaches 1.49 °C in urbanized areas during summer, with AH emission making a considerable contribution. The warming effect due to urban land use is intensified during extremely hot days, but in contrast, the AH effects are slightly reduced. Urban development increases the total thermal discomfort hours by 27% in the urban areas of YRD, with AH and urban land use contributing nearly equal amount. By limiting the daytime latent heat release, urban land use reduces the daily maximum heat stress particularly during extremely hot days; however, such alleviations can be offset by the AH emission. We conclude strategies for mitigation of urban heat island effect and heat stress in cities should therefore include measures to reduce AH emission.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Stochastic Pricing Game for Aggregated Demand Response Considering Comfort Level

In recent years, demand response (DR) has been explored as a fundamental strategy for demand-side management due to its advantages in mediating intermittency of renewable energy generation, load shifting, etc. To engage customers in DR programs, several deterministic price-based DR strategies have been developed and implemented. However, the stochastic weather conditions and occupants' consumption behaviors often make the deterministic solution less robust to uncertainties. In this paper, with the consideration of the uncertainties, a stochastic Stackelberg game is proposed to model the price-demand negotiation between a distributed system operator and load aggregators, where the virtual battery constraints are extracted from the building thermostatically controlled loads (TCLs)‘ characteristics to guarantee comfortable TCLs' levels. Following the negotiation, a priority-based control method is used to allocate the optimal aggregated power DR profile at the building level and track the power signal. Several groups of experiments have demonstrated the effectiveness and robustness of the stochastic solutions.

Chen, Yang↗
DOE OSTI2015

Integrated PEV Charging Solutions and Reduced Energy for Occupant Comfort [Brochure]

Brochure on Vehicle Testing and Integration Facility, featuring the Vehicle Modification Facility, Vehicle Test Pad and ReCharge Integrated Demonstration System. Plug-in electric vehicles (PEVs) offer the opportunity to shift transportation energy demands from petroleum to electricity, but broad adoption will require integration with other systems. While automotive experts work to reduce the cost of PEVs, fossil fueled cars and trucks continue to burn hundreds of billions of gallons of petroleum each year - not only to get from point A to point B, but also to keep passengers comfortable with air conditioning and heat. At the National Renewable Energy Laboratory (NREL), three installations form a research laboratory known as the Vehicle Testing and Integration Facility (VTIF). At the VTIF, engineers are developing strategies to address two separate but equally crucial areas of research: meeting the demands of electric vehicle-grid integration and minimizing fuel consumption related to vehicle climate control. Part of NREL's Center for Transportation Technologies and Systems (CTTS), the VTIF is dedicated to renewable and energy efficient solutions. This facility showcases technology and systems designed to increase the viability of sustainably powered vehicles. NREL researchers instrument every class of on-road vehicle, conduct hardware and software validation for electric vehicle (EV) components and accessories, and develop analysis tools and technology for the Department of Energy, other government agencies and industry partners. Research conducted at the VTIF examines the interaction of building energy systems, utility grids, renewable energy sources and PEVs, integrating energy management solutions, and maximizing potential greenhouse gas (GHG) reduction, while smoothing the transition and reducing costs for EV owners. NREL's collaboration with automakers, charging station manufacturers, utilities and fleet operators to assess technologies using VTIF resources is designed to enable PEV communication with the smart grid and create opportunities for vehicles to play an active role in building and grid management. Ultimately, this creates value for the vehicle owner and will help renewables be deployed faster and more economically, making the U.S. transportation sector more flexible and sustainable.

02 PETROLEUM↗
DOE OSTI2025

High-Fidelity Building Emulator for Integrated Comfort and Energy Analysis using EnergyPlus and Radiance

The growing need for smart, energy-efficient, and occupant-centric buildings has created a demand for advanced control systems that can optimize building operations to balance energy savings, demand flexibility, and comfort. However, current building energy simulation tools, such as EnergyPlus, have limitations that hinder the development and evaluation of these complex control systems. To address this challenge, we introduce a high-fidelity building emulator that dynamically couples EnergyPlus with Radiance for enhanced daylight modeling. The introduced workflow allows researchers and practitioners to rapidly develop and evaluate innovative control solutions. An example study looking at a south-facing office zone revealed up to 67% deviation in predicted light levels, which can significantly impact building assessment.

Yu, Tammie↗
NASA NTRS1972

Effect of neck warming and cooling on thermal comfort

The potential use of local neck cooling in an area superficial to the cerebral arteries was evaluated by circulating cold or hot water through two copper disks held firmly against the neck. Subjective responses indicated that neck cooling improves the thermal comfort in a hot environment.

Williams, B. A.↗
NASA NTRS1974

Exploratory tests of a simple aero-mechanical ride comfort system for lightly loaded aircraft

Some exploratory wind tunnel and radio-controlled free-flight tests were made with a small high-wing airplane model (1.23m wing span) to study the concept of a simple aero mechanical system intended to alleviate gust loads and improve ride comfort of lightly loaded aircraft. The system consisted essentially of the outer portions of each wing being hinged in the chordwise direction and connected directly to the wing flaps using internal counter weights to provide neutral mass balance. When the wing experienced a change in velocity or angle of attack, the movable wing panels, acting as sensors and flap actuators, deflected in response to the changes in lift on the wing. The corresponding movements of the interconnected flaps tended to reduce the changes in the wing lift.

Hewes, D. E.↗
NASA NTRS1974

Data on the acoustic comfort of passengers in railroad cars and soundproofing recommendations

Acoustic passenger comfort in railroad cars is represented by the following values: Total noise level in db, octave sound spectrum in db, and indices of intelligibility. The noise level perceived inside the car results from two components: one due to the penetration of air noise, and another due to the transmission of vibrations through solids. Measurement results show the necessity of improving bogie and bogie-body connections, intensification of soundproofing of the floor, adaption of windows with double panes, etc.

Tomescu, C.↗
NASA NTRS1975

Discussion of an aeromechanical gust alleviation system to improve the ride comfort of light airplanes

A discussion of an on-going NASA research project of a gust alleviation system to improve the ride comfort of a light airplane is presented. The discussion includes a description of the proposed system which uses auxiliary aerodynamic surfaces to drive the trailing-edge flaps. The results of analytical work on the effects of the system on stability and effectiveness of the system are presented. Static wind-tunnel tests of the system installed in a 1/6-scale model of a popular light airplane are also described. Problem areas which may need future investigation are discussed.

Stewart, E. C.↗
NASA NTRS1976

Passenger ride comfort technology for transport aircraft situations

Research in ride comfort and of the resultant technology is overviewed. Several useful relations derived from the technology are: input environments to the vehicle; aircraft operations; and aircraft configurations. Input environments which influence the ride motion environment consist of naturally occuring phenomena such as gusts or turbulence and man generated phenomena such as trailing vortex wakes or runway roughness. Aircraft operations influence ride environments in the form of motions caused by maneuvers, of pressure changes caused by rapid descents, or of too high temperature. Aircraft configurations influence the ride environment by size and shape of external surfaces which generate aerodynamic perturbing forces; by onboard equipment, such as power plant noise and vibrations; and by passive equipment which directly interfaces the passengers such as marginal size seats with limited elbowroom and legroom.

Conner, W.↗