Search NASA⌕ Search

SEARCH · Search NASA

Results for “Thermal Control System”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 10(exp 13) to 10(exp 15) n per square centimeters. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 10(exp 15) to 10(exp 16) n per square centimeters with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

Bowman, Cheryl L.↗
NASA NTRS1990

Modeling the use of a binary mixture as a control scheme for two-phase thermal systems

Two-phase thermal loops using mechanical pumps, capillary pumps, or a combination of the two have been chosen as the main heat transfer systems for the space station. For these systems to operate optimally, the flow rate in the loop should be controlled in response to the vapor/liquid ratio leaving the evaporator. By substituting a mixture of two non-azeotropic fluids in place of the single fluid normally used in these systems, it may be possible to monitor the temperature of the exiting vapor and determine the vapor/liquid ratio. The flow rate would then be adjusted to maximize the load capability with minimum energy input. A FLUINT model was developed to study the system dynamics of a hybrid capillary pumped loop using this type of control and was found to be stable under all the test conditions.

Benner, S. M.↗
NASA NTRS2013

Evaporative Cooling and Dehumidification Garment for Portable Life Support Systems

This paper describes the design and development of an innovative thermal and humidity control system for future space suits. The system comprises an evaporation cooling and dehumidification garment (ECDG) and a lithium chloride absorber radiator (LCAR). The ECDG absorbs heat and water vapor from inside the suit pressure garment, while the LCAR rejects heat to space without venting water vapor. The ECDG is built from thin, flexible patches with coversheets made of non-porous, water-permeable membranes that -enclose arrays of vapor flow passages. Water vapor from inside the spacesuit diffuses across the water permeable membranes, enters the vapor flow channels, and then flows to the LCAR, thus dehumidifying the internal volume of the space suit pressure garment. Additional water evaporation inside the ECDG provides cooling for sensible heat loads. -The heat released from condensation and absorption in the LCAR is rejected to the environment by thermal radiation. We have assembled lightweight and flexible ECDG pouches from prototypical materials and measured their performance in a series of separate effects tests under well-controlled, prototypical conditions. Sweating hot plate tests at typical space suit pressures show that ECDG pouches can absorb over 60 W/ft of latent heat and 20 W/ft of sensible heat from the pressure garment environment. These results are in good agreement with the predictions of our analysis models.

Izenson, Michael↗
DOE OSTI2019

SPC-2734 Chromalox Oil Heater System Procurement Specification

This specification will supply the necessary technical information to the vendor to allow them to provide the system we need for the Thermal Energy Delivery System (TEDS) construction. TEDS is being constructed within the dynamic energy transport and integration laboratory (DETAIL) facility to test heat transfer components, distribution systems, instruments, and controls that can be monitored and controlled for hybrid generation of electrical power and/or non-electrical products. TEDS is designed to operate as a part of an integrated system or independently to demonstrate component operations, to develop and validate thermal energy transport models and control systems, and to study thermal energy inertia and storage. Within the integrated system, TEDS will be connected to the INL Real Time Digital Simulator (RTDS) test platform to develop and demonstrate monitoring and control systems and to investigate real-time, hardware-in-the-loop response characteristics relative to grid operations. As the basis of the TEDS, Chromalox (the vendor) has been chosen to design and supply a heater, pump, storage tanks, and pressure vessel due to their experience with industrial-scale heat transfer oil systems.

25 ENERGY STORAGE↗
DOE OSTI2014

Control mechanism for attenuation of thermal energy pulses using cold circulators in the cryogenic distribution system of fusion devices in tokamak configuration

Operation and control of superconducting (SC) magnets in the fusion devices having tokamak configuration opens up the domain of varying peak thermal energy environment as a function of time, commensurate with the plasma pulses. The varied thermal energy environment, thus propagated to upstream of the cooling system, is responsible for the system level instability of the overall cryogenic system. The cryogenic distribution system, the regime of first impact point, therefore, has to be tuned so as to stay at the nearly stable zone of operation. The configuration of the cryogenic distribution system, considered in the present study, involves a liquid helium (LHe) bath as a thermal buffer, LHe submerged heat exchangers and cold circulator apart from the valves for implementations of the precise controls. The cold circulator supplies the forced flow supercritical helium, used for the cooling of SC magnets. The transients of the thermal energy pulses can be attenuated in the cryogenic distribution system by various methodologies. One of the adopted methodologies in the present study is with the precise speed control of the cold circulators. The adopted methodology is applied to various configurations of arrangements of internal components in the distribution system for obtaining system responses with superior attenuation of energy pulses. The process simulation approach, assumptions, considered inputs and constraints, process modeling with different configuration as well as results to accomplish the control scheme for the attenuation of the thermal energy pulses are described.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Analysis of the Effect of Vehicle Platooning on the Optimal Control of a Heavy Duty Engine Thermal System

One promising method for reducing fuel consumption and emissions, particularly in heavy duty trucks, is platooning. As the distance between vehicles decreases, the following vehicles will experience less aerodynamic drag on the front of the vehicle. However, reducing the velocity of the air contacting the front of the vehicle could have adverse effects on the temperature of the engine. To compensate for this effect, the energy consumption of the engine cooling system might increase, ultimately limiting the overall improvements obtained with platooning. Understanding the coupling between drag reduction and engine cooling load requirement is key for successfully implementing platooning strategies. Additionally, in a Connected and Automated Vehicle (CAV) environment, where information of the future engine load becomes available, the operation of the cooling system can be optimized in order to achieve the maximum fuel consumption reduction. In this paper, a control-oriented physics-based model for the engine cooling loop of a Volvo engine is developed and validated against road data. Starting from the validated model, an optimal control problem for the coolant system is formulated considering the tradeoff between the tracking of the engine temperature setpoint and the corresponding fuel consumption under different trailing distances. To compare the coolant system performance, Dynamic Programming (DP) is used to determine the global optimal solution for the coolant system actuator. The coupling between optimal cooling system operation and reduction in ram air are evaluated by comparing the results obtained from the DP under different platooning conditions against the unrestricted scenario. In addition, the paper analyzes the changes in the tradeoff between fuel consumption and setpoint tracking for different vehicle distances. This analysis will provide useful insight on the sensitivity of the coolant system controller calibration to the platoon distance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRSDate not supplied

Analytical Review of Exploration Extravehicular Mobility Unit Heat Rejection Performance

The Primary Thermal Control Loop (PTCL) in the Exploration Extravehicular Mobility Unit (xEMU) uses a Spacesuit Water Membrane Evaporator (SWME) to provide cooling for the crew member and spacesuit avionics. A secondary emergency cooling system, the Auxiliary Thermal Control Loop (ATCL), also uses a smaller version of the SWME, called the Mini-ME, in the event of a failure in the primary system. These are integral to the comfort of the crew member (through heat rejection) during an Extravehicular Activity (EVA). This paper examines the effectiveness of the heat rejection of the PTCL and the ATCL during thermal vacuum testing and the absolute limit of heat rejection to maintain an approximately 10C outlet temperature. During this thermal vacuum test, the PTCL was taken from a heat input of 0W up to 900W, far past the design point, and the ATCL was tested from 0W to 300W. Testing showed that the PTCL and the ATCL can maintain crew member outlet temperature throughout an entire 8-hour thermally controlled EVA environment (hot and cold). The results and effectiveness of the test will be detailed throughout this paper for all EVAs (whether a full mapping profile or a standard continuous heat load).

PLSS↗
NASA NTRS2003

Spacecraft Design Thermal Control Subsystem

This slide presentation reviews the functions of the thermal control subsystem engineers in the design of spacecraft. The goal of the thermal control subsystem that will be used in a spacecraft is to maintain the temperature of all spacecraft components, subsystems, and all the flight systems within specified limits for all flight modes from launch to the end of the mission. For most thermal control subsystems the mass, power and control and sensing systems must be kept below 10% of the total flight system resources. This means that the thermal control engineer is involved in all other flight systems designs. The two concepts of thermal control, passive and active are reviewed and the use of thermal modeling tools are explained. The testing of the thermal control is also reviewed.

thermal control↗
DOE OSTI2018

Renovation of Thermal Vacuum Chambers at Idaho National Laboratory (INL) for Testing of Radioisotope Power Systems (RPS)

The Radioisotope Power Systems (RPS) program at Idaho National Laboratory (INL) fuels and performs environmental testing of RPS in support of National Aeronautics and Space Administration (NASA) missions. Recently the programs’ thermal vacuum chambers, housed within INL’s Space and Security Power Systems Facility (SSPSF), underwent successful renovations to improve functional capabilities and system control in support of customer missions. Thermal vacuum system renovations focused primarily on three core functions. The first focus area was integration of semi-automated Programmable Logic Controllers (PLC) to enhance operational feedback and process control. This included the use of numerically controlled vacuum valves and integration of real time feedback from process pressure transducers. Improvements to the system high vacuum pumping technology was the second priority focus. Legacy diffusion pumps were replaced with turbo-molecular and cryogenic pumps to help mitigate the possibility of back streaming diffusion pump oil onto the surface of the test article or radiative cooling surfaces located within the chambers. The third and final core function involved meeting emergent customer thermal requirements. This led to retro-fitting one of the vacuum chambers with a cryogenically cooled Thermal Conditioning Unit (TCU) and thermal shrouds. The TCU utilizes gaseous nitrogen to heat or cool a cylindrical shroud to maintain a set temperature with a programmable range of -I85 °C to I00 °C. With the successful completion of RPS acceptance testing, the newly renovated thermal vacuum chamber systems are operational and better equipped to support testing of Radioisotope Power Systems for space exploration missions.

42 ENGINEERING↗
DOE OSTI2018

Renovation of Thermal Vacuum Chambers at Idaho National Laboratory for Testing of Radioisotope Power Systems

The Radioisotope Power Systems (RPS) program at Idaho National Laboratory (INL) fuels and performs environmental testing of RPS in support of National Aeronautics and Space Administration (NASA) missions. Recently the programs’ thermal vacuum chambers, housed within INL’s Space and Security Power Systems Facility (SSPSF), underwent successful renovations to improve functional capabilities and system control in support of customer missions. Thermal vacuum system renovations focused primarily on three core functions. The first focus area was integration of semi-automated Programmable Logic Controllers (PLC) to enhance operational feedback and process control. This included the use of numerically controlled vacuum valves and integration of real time feedback from process pressure transducers. Improvements to the system high vacuum pumping technology was the second priority focus. Legacy diffusion pumps were replaced with turbo-molecular and cryogenic pumps to help mitigate the possibility of back streaming diffusion pump oil onto the surface of the test article or radiative cooling surfaces located within the chambers. The third and final core function involved meeting emergent customer thermal requirements. This led to retro-fitting one of the vacuum chambers with a cryogenically cooled Thermal Conditioning Unit (TCU) and thermal shrouds. The TCU utilizes gaseous nitrogen to heat or cool a cylindrical shroud to maintain a set temperature with a programmable range of -I85 °C to I00 °C. With the successful completion of RPS acceptance testing, the newly renovated thermal vacuum chamber systems are operational and better equipped to support testing of Radioisotope Power Systems for space exploration missions.

42 ENGINEERING↗
DOE OSTI2018

Renovation of Thermal Vacuum Chambers at Idaho National Laboratory (INL) for Testing of Radioisotope Power Systems (RPS)

The Radioisotope Power Systems (RPS) program at Idaho National Laboratory (INL) fuels and performs environmental testing of RPS in support of National Aeronautics and Space Administration (NASA) missions. Recently the programs’ thermal vacuum chambers, housed within INL’s Space and Security Power Systems Facility (SSPSF), underwent successful renovations to improve functional capabilities and system control in support of customer missions. Thermal vacuum system renovations focused primarily on three core functions. The first focus area was integration of semi-automated Programmable Logic Controllers (PLC) to enhance operational feedback and process control. This included the use of numerically controlled vacuum valves and integration of real time feedback from process pressure transducers. Improvements to the system high vacuum pumping technology was the second priority focus. Legacy diffusion pumps were replaced with turbo-molecular and cryogenic pumps to help mitigate the possibility of back streaming diffusion pump oil onto the surface of the test article or radiative cooling surfaces located within the chambers. The third and final core function involved meeting emergent customer thermal requirements. This led to retro-fitting one of the vacuum chambers with a cryogenically cooled Thermal Conditioning Unit (TCU) and thermal shrouds. The TCU utilizes gaseous nitrogen to heat or cool a cylindrical shroud to maintain a set temperature with a programmable range of -I85 °C to I00 °C. With the successful completion of RPS acceptance testing, the newly renovated thermal vacuum chamber systems are operational and better equipped to support testing of Radioisotope Power Systems for space exploration missions.

42 ENGINEERING↗
DOE OSTI2022

Model Predictive Control for a Grid-interactive Efficient Thermal Storage-integrated Heat Pump System

Building heating and cooling systems can be used to overcome the mismatch between the intermittent supply of renewable power and the fluctuating demand for electricity. A novel underground thermal energy storage integrated with a dual-source heat pump has been proposed to mitigate the mismatch while meeting the thermal demand of buildings efficiently. Conventional thermostat control with heuristic rules cannot provide intelligent decisions to maximize the thermal efficiency and flexibility of the proposed system. Advanced control strategies like model predictive control (MPC) have provided a new paradigm for grid-interactive efficient building operation with the advancement of computation and sensing. This study developed an MPC for the proposed system to provide grid service for Demand Side Management and minimize the operating cost of building owners. A control-oriented dynamic model of the proposed system has been developed. Given an objective function and proper constraints, an optimization problem is formulated to determine the optimal control strategy of the system. Dynamic Programming is adopted to solve the optimization problem. A rule-based control (RBC) is also developed to achieve similar goals. Short-term simulations are conducted to compare the system performance resulting from the two controls. The simulation results indicate that the MPC performs more intelligently than the RBC in charging thermal energy storage and selecting heat pump sources by taking advantage of the predicted cooling demands of the building and the performance of the integrated system. As a result, the MPC could save energy and reduce operating costs compared with the RBC. A case study shows that, for a 3-day operation, the MPC saves 36.9% energy and reduces 38.5% operating cost compared with the RBC.

Shi, Liang↗
NASA NTRS1992

Temperature and heat flux measurements: Challenges for high temperature aerospace application

The measurement of high temperatures and the influence of heat transfer data is not strictly a problem of either the high temperatures involved or the level of the heating rates to be measured at those high temperatures. It is a problem of duration during which measurements are made and the nature of the materials in which the measurements are made. Thermal measurement techniques for each application must respect and work with the unique features of that application. Six challenges in the development of measurement technology are discussed: (1) to capture the character and localized peak values within highly nonuniform heating regions; (2) to manage large volumes of thermal instrumentation in order to efficiently derive critical information; (3) to accommodate thermal sensors into practical flight structures; (4) to broaden the capabilities of thermal survey techniques to replace discrete gages in flight and on the ground; (5) to provide supporting instrumentation conduits which connect the measurement points to the thermally controlled data acquisition system; and (6) to develop a class of 'vehicle tending' thermal sensors to assure the integrity of flight vehicles in an efficient manner.

Neumann, Richard D.↗
NASA NTRS1997

Evaluation of Thermal Control Coatings for Flexible Ceramic Thermal Protection Systems

This report summarizes the evaluation and testing of high emissivity protective coatings applied to flexible insulations for the Reusable Launch Vehicle technology program. Ceramic coatings were evaluated for their thermal properties, durability, and potential for reuse. One of the major goals was to determine the mechanism by which these coated blanket surfaces become brittle and try to modify the coatings to reduce or eliminate embrittlement. Coatings were prepared from colloidal silica with a small percentage of either SiC or SiB6 as the emissivity agent. These coatings are referred to as gray C-9 and protective ceramic coating (PCC), respectively. The colloidal solutions were either brushed or sprayed onto advanced flexible reusable surface insulation blankets. The blankets were instrumented with thermocouples and exposed to reentry heating conditions in the Ames Aeroheating Arc Jet Facility. Post-test samples were then characterized through impact testing, emissivity measurements, chemical analysis, and observation of changes in surface morphology. The results show that both coatings performed well in arc jet tests with backface temperatures slightly lower for the PCC coating than with gray C-9. Impact testing showed that the least extensive surface destruction was experienced on blankets with lower areal density coatings.

Kourtides, Demetrius↗
NASA NTRS2017

Improving Satellite Compatible Microdevices to Study Biology in Space

The technology for biology in space lags far behind the gold standard for biological experiments on Earth. To remedy this disparity, the Rothschild lab works on proof of concept, prototyping, and developing of new sensors and devices to further the capabilities of biology research on satellites. One such device is the PowerCell Payload System. One goal for synthetic biology in aiding space travel and colonization is to genetically engineer living cells to produce biochemicals in space. However, such farming in space presupposes bacteria retain their functionality post-launch, bombarded by radiation, and without the 1G of Earth. Our questions is, does a co-culture of cyanobacteria and protein-synthesizing bacteria produce Earth-like yields of target proteins? Is the yield sensitive to variable gravitational forces? To answer these questions, a PowerCell Payload System will spend 1 year aboard the German Aerospace Center's Euglena and Combined Regenerative Organic-food Production In Space (Eu:CROPIS) mission satellite. The PowerCell system is a pair of two 48-well microfluidic cards, each well seeded with bacteria. The system integrates fluidic, thermal, optical, electronic, and control systems to germinate bacteria spores, then measure the protein synthesized for comparison to parallel experiments conducted on the Earth. In developing the PowerCell Payload, we gained insight into the shortcomings of biology experiments on satellites. To address these issues, we have started three new prototyping projects: 1) The development of an extremely stable and radiation resistant cell-free system, allowing for the construction of proteins utilizing only cell components instead of living cells. This can be lyophilized on a substrate, like paper. (2) Using paper as a microfluidic platform that is flexible, stable, cheap, and wicking. The capillary action eliminates the need for pumps, reducing volume, mass, and potential failing points. Electrodes can be printed on the paper to sense for biochemicals. (3) Developing a modular, semi-autonomous microfluidic device that can be easily adapted for a variety of common biological experiments. This versatility will allow for quicker and cheaper experimentation. These improvements to satellite experiment platforms have the potential to radically increase the return from NASA's biological and field studies with reduced development time, mass, and cost with increased robustness data and interpretation.

biology in spac↗
DOE OSTI2017

Control strategies for coupling thermal energy storage systems with small modular reactors - 188

The contribution of intermittent (renewable) energy sources such as wind and solar continues to increase as renewables improve in both efficiency and price-point. However, the variability of renewables generates additional challenges for the electric grid in the form of rapidly varying electric loads. Proposed options for accommodating this load have included operating nuclear reactors in a load follow mode, or operating the reactor at or near steady state and bypassing steam directly to the condenser. Both of these strategies result in lost energy potential. In addition to lost energy potential, load follow operation can result in increased stress on the fuel and other mechanical components. A more attractive approach is to operate the reactor at or near steady state and bypass excess steam to a thermal energy storage system. The thermal energy can then be recovered, either for electric generation during periods of peak electric demand, or for use in ancillary applications such as desalination and hydrogen production. Sensible Heat Thermal Energy Storage is a mature technology currently used in solar energy systems. This research focuses on the design and coupling of such a system to Small Modular Reactors (SMRs), typical of Integral Pressurized Water Reactor (IPWR) designs currently under development. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗