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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Consideration of the Impact of the Environmental Conditions when Designing Heat-Receiving Systems of the Solar Cylindrical Parabolic Modules

The aerohydrodynamic and heat exchange characteristics in the cylindrical heat receiver of a solar cylindrical parabolic concentrating module are investigated. The mathematical model is based on the Navier- Stokes equation system for a laminar flow in a channel. The model is implemented using the control volume method. The created computer algorithm allows carrying out parametric studies and revealing the most rational geometric, dynamic, and power parameters of the process. The proposed model describes the general physical outlines of the heat exchange in a cylindrical heat receiver which allows estimating the influence of the environment—wind velocity, ambient temperature, etc.—on it.

14 SOLAR ENERGY↗
DOE OSTI2020

PWR decay heat removal system in which steam from the pressurizer drives a turbine which drives a pump to inject water into the reactor pressure vessel

In conjunction with a pressurized water reactor (PWR) and a pressurizer configured to control pressure in the reactor pressure vessel, a decay heat removal system comprises a pressurized passive condenser, a turbine-driven pump connected to suction water from at least one water source into the reactor pressure vessel; and steam piping configured to deliver steam from the pressurizer to the turbine to operate the pump and to discharge the delivered steam into the pressurized passive condenser. The pump and turbine may be mounted on a common shaft via which the turbine drives the pump. The at least one water source may include a refueling water storage tank (RWST) and/or the pressurized passive condenser. A pressurizer power operated relief valve may control discharge of a portion of the delivered steam bypassing the turbine into the pressurized passive condenser to control pressure in the pressurizer.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2021

PWR decay heat removal system in which steam from the pressurizer drives a turbine which drives a pump to inject water into the reactor pressure vessel

In conjunction with a pressurized water reactor (PWR) and a pressurizer configured to control pressure in the reactor pressure vessel, a decay heat removal system comprises a pressurized passive condenser, a turbine-driven pump connected to suction water from at least one water source into the reactor pressure vessel; and steam piping configured to deliver steam from the pressurizer to the turbine to operate the pump and to discharge the delivered steam into the pressurized passive condenser. The pump and turbine may be mounted on a common shaft via which the turbine drives the pump. The at least one water source may include a refueling water storage tank (RWST) and/or the pressurized passive condenser. A pressurizer power operated relief valve may control discharge of a portion of the delivered steam bypassing the turbine into the pressurized passive condenser to control pressure in the pressurizer.

Graham, Thomas G.↗
DOE OSTI2020

An Assessment of Impacts on Electric End-Use Load Profile of a Typical Residential Building from a Ground Source Heat Pump Systems Integrated with Underground Thermal Energy Storage

Buildings are the primary users of electricity, and a considerable amount of electric energy consumed in residential and commercial buildings is for meeting thermal demands (e.g., space heating/cooling, water heating, etc.). Therefore, integrating thermal energy storage with a building’s energy system has the potential to reshape the electric load profile of the building and mitigate the mismatch between the renewable power supply and the thermal demands of buildings. A novel ground-source heat pump system (GSHP) integrated with underground thermal energy storage (UTES) has been developed to enable flexible electric demand at buildings while meeting their thermal demands with an energy-efficient GSHP system. This paper assessed the potential impacts of the proposed system on the peak electrical demand and annual electricity consumption in a typical residential building at various climate zones in the United States. The results show that by replacing the conventional HVAC system (air conditioner and natural gas furnace) with the UTES integrated GSHP system, summer peak electric demand can be reduced by 27% to 50% depending on the weather. Although the winter peak electrical demand could be increased by up to 70% if the proposed system replaces natural gas furnace, the existing electricity supply system for single-family homes in most regions of the United States have adequate capacity for the replacement. While eliminating the natural gas consumption for space heating, the proposed system consumes more electricity on an annual basis in heating-dominated regions. However, it consumes less electricity in cooling dominated regions. The resulting variance in annual electricity consumption in various climate zones is within 15% compared with the baseline system.

Shi, Liang↗
NASA NTRS2005

Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

An advantage of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used for a number of beneficial purposes including: maintaining electronic components within a controlled temperature range, warming propulsion tanks and mobility actuators, and maintaining liquid propellants above their freezing temperature. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated large quantities of waste heat due to the low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-Watt Stirling Radioisotope Generator (SRG110) will have higher conversion efficiencies, thereby rejecting less waste heat at a lower temperature and may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of ~6 to 7 percent, reject their waste heat at the relatively high heat rejection temperature of 200 C. This is an advantage when rejecting heat to space; however, transferring heat to the internal spacecraft components requires a large and heavy radiator heat exchanger. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation of the RTG. The SRG110, with an efficiency around 22 percent and 50 C nominal housing surface temperature, can readily transfer the available waste heat directly via heat pipes, thermal straps, or fluid loops. The lower temperatures associated with the SRG110 avoid the chances of overheating other scientific components, eliminating the need for thermal shields. This provides the spacecraft designers more flexibility when locating the generator for a specific mission. A common misconception with high-efficiency systems is that there is not enough waste heat for spacecraft thermal management. This paper will dispel this misconception and investigate the use of a high-efficiency SRG110 for spacecraft thermal management and outline potential methods of waste heat utilization in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander). The advantages associated with the SRG110 as they relate to ease of assembly, less complex interfaces, and overall mass savings for a spacecraft will be highlighted.

Pantano, David R.↗
DOE OSTI2021

Increase resistance for efficient heating

Conductors for use in heating systems are provided. The conductors are configured to have an extended current path for the current and increased resistance as seen by the current. The heating system may be an induction system. For example, the conductor may comprise a conductive material having a surface which faces an induction coil of an oscillating circuit. This surface may have a predetermined pattern of peaks and valleys. The peaks and valleys form a non-linear current path for the induced current when exposed to an electromagnetic field generated by the oscillating circuit. Other conductors such as a heat pipe may be used. The pipe may have walls with varying thicknesses over its length. The varying thicknesses may include a first thickness and a second thickness which alternate. The heat pipe may be used in an induction or direct contact heating system where AC is directly applied to the pipe.

Kisner, Roger A.↗
DOE OSTI2025

Dual-season thermal energy storage-integrated heat pump system for load shifting: experiments, modeling and nationwide analysis

Here, this paper proposes and validates a dual-season thermal energy storage-integrated heat pump (TES-HP) system that shifts building electric load in both cooling and heating modes using a single phase-change TES. The design uses the TES as a heat sink for the condenser in summer and a heat source for the evaporator in winter, thereby reducing on-peak electric demand while ensuring compatible with existing air-distribution systems. A 14-kW TES-HP prototype with six operating modes and novel refrigerant charge management strategies was experimentally tested under varied conditions. Subsequently, data-driven polynomial performance curves were developed and validated against experiments, then coupled with a phase change material (PCM) model and a calibrated building model within a rule-based controller. Single-day case studies demonstrated effective on-peak demand reduction while maintaining thermal comfort. During cooling, hourly power was lowered by up to 1.5 kW; in heating, average hourly power decreased from over 3.5 kW to 1.8 kW, compared to an HP-only system, achieving 64.5 % load shifting, and the need for resistance heating was eliminated. Seasonal simulations showed typical on-peak electricity savings of 25–35 % in cooling and 40–65 % in heating, with the largest benefits on the hottest and coldest days. Extended response-surface analysis and nationwide mapping quantified load shifting as functions of ambient and TES temperatures, revealing a seasonal trade-off in TES phase-change temperature. These results demonstrate the TES-HP system as a practical and scalable solution for grid-interactive buildings that reduces on-peak demand and electricity use while maintaining thermal comfort and enhancing grid flexibility and reliability.

Grid-interactive buildings↗
NASA NTRS2019

Mechanical design and stress analysis challenges overcome to ensure the structural integrity of Europa Clipper's mechanical pumped fluid loop Heat Redistribution System (HRS)

Launching in 2023, NASA’s Europa Clipper mission will place a spacecraft into a long, looping orbit around Jupiter to perform a series of close flyby investigations of its moon Europa. Strong evidence suggests that Europa hosts an ocean of liquid water beneath its icy crust that could harbor conditions favorable for life. The spacecraft is currently under development by the Jet Propulsion Laboratory (JPL) and the Applied Physics Laboratory (APL) and nearing completion of its Detailed Design Phase. A Mechanical Pumped Fluid Loop (MPFL) architecture known as the Heat Redistribution System (HRS) has been baselined to provide power efficient thermal control of the sensitive components within the Avionics, Radio Frequency (RF), and Propulsion Modules. Principally, the HRS harvests waste heat from the onboard dissipating equipment and distributes it to a 1.4 m diameter by 3 m tall cylindrical structure that cocoons and keeps the propulsion subsystem warm. Numerous technical issues had to be resolved in order to securely attach nearly 100 m of HRS tubing to the spacecraft, which is predicted to experience high launch loads. This paper will review the relevant environments and mission constraints as well as outline the stress and fatigue analysis approach taken to verify the detailed mechanical design of the HRS.

Kolenz, Daniel↗
DOE OSTI2022

Numerical simulations of membrane distillation systems with actively heated membranes

Membrane distillation (MD) is a thermal desalination process that is gaining attention for treating hypersaline brines. One recent approach uses composite membranes with a thermally conductive layer that delivers heat to the membrane–feed interface, where it drives evaporation. Though this increases single-pass recovery, it comes with the challenge of promoting lateral heat conduction through the thin membrane. Herein, we develop a 3D, computational fluid dynamics (CFD) model that simulates conjugate heat, mass, and momentum transport in the feed channel and composite membrane. We then use the CFD to verify a simpler numerical model that approximates the feed velocity field analytically. We validate the numerical model experimentally, and use it to investigate the impacts of the conductive layer thickness, feed channel geometry, and operating conditions on temperature and concentration polarization, permeate production, and specific energy consumption. Overall, we find that lateral heating increases permeate production at the expense of increased concentration polarization. In extreme cases, the concentration increases more than four-fold along the membrane surface. Furthermore, we show however, that the feed flow rate and conductive layer thickness can be tailored to mitigate concentration polarization, for only a small reduction in permeate production.

42 ENGINEERING↗
NASA NTRS2022

Performance Evaluation of a Vapor-compression-cycle Based Heat Pump System for a Lunar Habitat under the Impact of Dust Deposits on the Coupled Radiators

Space exploration gains new momentum. A near goal is set by NASA to return humans to the Moon andestablish a sustainable presence on the lunar surface for more repeatable and affordable expeditions.The lunar dust is one of the dangerous environment hazard causing serious problems for explorationactivities. In this paper, in order to study the impact of lunar dust on the performance of a thermalmanagement system for a lunar habitat, a dynamical model of an active thermal control system that iscomprised of a vapor-compression cycle heat pump and a radiator loop is developed. A heat pump to liftthe heat rejection temperature is required due to high lunar daytime surface temperature. Parametricstudies on radiator size, percentage of dust coverage on the radiator, and lunar habitat location arecarried out. The results show that lunar deposits can significantly increase the power consumption ofthe thermal management system. A dust covered radiator panel results in net heat input to the heattransfer fluid during the period of strong solar irradiance, causing deteriorated performance of theradiator loop. The lunar dust contamination problem raises the requirement of redundancy design of asystem for fault tolerance. A synergetic design of a thermal management system, a power generationsystem and robotic maintenance system is proposed to achieve maximal mass cut for a whole lunarhabitat system.

Chunjian Pan↗
NASA NTRS1985

Heat transfer in aeropropulsion systems

Aeropropulsion heat transfer is reviewed. A research methodology based on a growing synergism between computations and experiments is examined. The aeropropulsion heat transfer arena is identified as high Reynolds number forced convection in a highly disturbed environment subject to strong gradients, body forces, abrupt geometry changes and high three dimensionality - all in an unsteady flow field. Numerous examples based on heat transfer to the aircraft gas turbine blade are presented to illustrate the types of heat transfer problems which are generic to aeropropulsion systems. The research focus of the near future in aeropropulsion heat transfer is projected.

Simoneau, R. J.↗
DOE OSTI2015

System-Level Heat Transfer Analysis, Thermal- Mechanical Cyclic Stress Analysis, and Environmental Fatigue Modeling of a Two-Loop Pressurized Water Reactor. A Preliminary Study

This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in April 2015 under the work package for environmentally assisted fatigue under DOE's Light Water Reactor Sustainability program. In this report, updates are discussed related to a system level preliminary finite element model of a two-loop pressurized water reactor (PWR). Based on this model, system-level heat transfer analysis and subsequent thermal-mechanical stress analysis were performed for typical design-basis thermal-mechanical fatigue cycles. The in-air fatigue lives of components, such as the hot and cold legs, were estimated on the basis of stress analysis results, ASME in-air fatigue life estimation criteria, and fatigue design curves. Furthermore, environmental correction factors and associated PWR environment fatigue lives for the hot and cold legs were estimated by using estimated stress and strain histories and the approach described in NUREG-6909. The discussed models and results are very preliminary. Further advancement of the discussed model is required for more accurate life prediction of reactor components. This report only presents the work related to finite element modelling activities. However, in between multiple tensile and fatigue tests were conducted. The related experimental results will be presented in the year-end report.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS1973

Reactor moderator, pressure vessel, and heat rejection system of an open-cycle gas core nuclear rocket concept

A preliminary design study of a conceptual 6000-megawatt open-cycle gas-core nuclear rocket engine system was made. The engine has a thrust of 196,600 newtons (44,200 lb) and a specific impulse of 4400 seconds. The nuclear fuel is uranium-235 and the propellant is hydrogen. Critical fuel mass was calculated for several reactor configurations. Major components of the reactor (reflector, pressure vessel, and waste heat rejection system) were considered conceptually and were sized.

Taylor, M. F.↗
DOE OSTI2024

Advanced Airfoils for Efficient Combined Heat Power Systems: Task 4.3 - Gas Turbine Machinery and Systems

Industrial gas turbines are commonly used in steam combined heat and power (CHP) applications. CHP applications have significant environmental and economic benefits that are consistent with the goals of the U.S. Department of Energy. This presentation provides a status update for a DOE effort investigating the impacts of advanced internal cooling technologies for small (5-10 MW) gas turbine CHP applications. The potential efficiency impacts are 2-3 percentage points based on the model and the cooling technologies investigated in this project.

Straub, Douglas↗
NASA NTRS1978

Prototype solar-heating system-engineering analysis

Space and domestic-water solar-heating prototype was tested in three phases: simulated energy function, winter normal operation, summer normal operation. Prototype was judged suitable for field installation.

Source record↗
NASA NTRS1978

Prototype solar heating and cooling systems

Prototype solar heating and cooling systems are described. Development, manufacture, test, system installation, maintenance, problem resolution, and performance evaluation are discussed.

Source record↗