Conenser Heat Rejection Systems Monthly Progress Report, 25 Feb. - 24 Mar. 1962
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CONDENSER↗
SEARCH · Engineering Papers
Results for “Heating systems”
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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Study of critical defects in ablative heat shield systems for the space shuttle
Results are presented from an investigation to determine the effects of fabrication-induced defects on the performance of an ablative heat shield material in a simulated space shuttle reentry environment. Nondestructive methods for detecting the defects were investigated. The material considered is a fiber-filled, honeycomb-reinforced, low-density elastomer. Results were obtained for density variations, voids, fiber bundles, crushed honeycomb, undercut honeycomb, unbonded areas, face sheet delaminations, and cure variations. The data indicate that, within reasonable tolerances, the fabrication defects investigated are not critical in terms of reentry performance of the heat shield.
Thompson, R. L.↗
Microwave Heating-Induced Temperature Gradients in Liquid–Liquid Biphasic Systems
Microwaves (MWs) can enable the electrification and intensification of chemical manufacturing. They have been applied to various unit separations, such as drying, distillation, and extraction, entailing gas–liquid and solid–liquid systems. However, a limited quantitative understanding of MW-heated liquid–liquid biphasic systems related to extraction exists. This work measures the temporal and spatial temperature difference between an aqueous and an organic phase in batch and continuous microfluidic modes. We demonstrate permanent temperature differences between phases over 35 °C and spatiotemporal periodic and quasiperiodic oscillations modulated by the flow patterns. The temperature differences are primarily driven by the faster absorption rate of MW irradiation by the aqueous phase versus the slower heat transfer from the aqueous phase to the organic phase. These are amplified by low specific interfacial area and modifications of the electromagnetic field. We employ a multiphysics model to predict the temperature difference in a batch system. The model is in good agreement with the experiments. We demonstrate a strong effect of input power, dielectric properties of organic solvents, the volume of solvents, and the volume ratio between phases on the temperature difference. A simple analytical model describes the temperature difference and provides design principles. Furthermore, the combined approach offers new insights into the design and optimization of the MW-heated biphasic systems.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
An optical multipass radiation system (OMRS) for heating levitated samples
The present system for spaceborne containerless material sample heating uses lamp systems with heating efficiencies of the order of 65 percent, potentially producing 30 W/sq mm over areas of 0.3 sq cm. The effectiveness of these lamp systems has its basis in the 'multipassing' of the lamp beams to recycle fluxes not absorbed by the sample during the initial pass. The actual multipass system's performance will have a power-law dependence on the quality of the coatings and optical surfaces illuminated; a detailed study of the spectral and dichroic characteristics, surface-scattering, and optical figure specifications of the system must be completed for full characterization.
Morrow, W. H.↗
An arc control and protection system for the JET lower hybrid antenna based on an imaging system
Arcs are the potentially most dangerous events related to Lower Hybrid (LH) antenna operation. If left uncontrolled they can produce damage and cause plasma disruption by impurity influx. To address this issue an arc real time control and protection imaging system for the Joint European Torus (JET) LH antenna has been implemented. The LH system is one of the additional heating systems at JET. It comprises 24 microwave generators (klystrons, operating at 3.7 GHz) providing up to 5 MW of heating and current drive to the JET plasma. This is done through an antenna composed of an array of waveguides facing the plasma. The protection system presented here is based primarily on an imaging arc detection and real time control system. It has adapted the ITER like wall hotspot protection system using an identical CCD camera and real time image processing unit. A filter has been installed to avoid saturation and spurious system triggers caused by ionization light. The antenna is divided in 24 Regions Of Interest (ROIs) each one corresponding to one klystron. If an arc precursor is detected in a ROI, power is reduced locally with subsequent potential damage and plasma disruption avoided. The power is subsequently reinstated if, during a defined interval of time, arcing is confirmed not to be present by image analysis. This system was successfully commissioned during the restart phase and beginning of the 2013 scientific campaign. Since its installation and commissioning, arcs and related phenomena have been prevented. In this contribution we briefly describe the camera, image processing, and real time control systems. Most importantly, we demonstrate that an LH antenna arc protection system based on CCD camera imaging systems works. Examples of both controlled and uncontrolled LH arc events and their consequences are shown.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Twelve solar-heating/cooling systems: Design and development
Two quarterly reports describe first 6 months of development on single family, multifamily, and commercial installations in Minneapolis area. Reports discuss basic requirements, and reasons for selecting specific configurations. Systems consist of liquid cooled flat plate collectors, two fluid loops, and gas-fired forced-air auxiliary heat source.
Source record↗
Study of critical defects in ablative heat shield systems for the space shuttle
Experimental results are presented for a program conducted to determine the effects of fabrication-induced defects on the performance of an ablative heat shield material. Exposures representing a variety of space shuttle orbiter mission environments-humidity acoustics, hot vacuum and cold vacuum-culuminating in entry heating and transonic acoustics, were simulated on large panels containing intentional defects. Nondestructive methods for detecting the defects, were investigated. The baseline materials were two honeycomb-reinforced low density, silicone ablators, MG-36 and SS-41. Principal manufacturing-induced defects displaying a critical potential included: off-curing of the ablator, extreme low density, undercut (or crushed) honeycomb reinforcements, and poor wet-coating of honeycomb.
Miller, C. C.↗
Analyzing Design Heating Loads in Superinsulated Buildings
The U.S. Department of Energy’s Building America research team Consortium for Advanced Residential Buildings (CARB) worked with the EcoVillage cohousing community in Ithaca, New York, on the Third Residential EcoVillage Experience neighborhood. This communityscale project consists of 40 housing units—15 apartments and 25 single-family residences. Units range in size from 450 ft2 to 1,664 ft2 and cost from $80,000 for a studio apartment to $235,000 for a three- or four-bedroom single-family home. For the research component of this project, CARB analyzed current heating system sizing methods for superinsulated homes in cold climates to determine if changes in building load calculation methodology should be recommended. Actual heating energy use was monitored and compared to results from the Air Conditioning Contractors of America’s Manual J8 (MJ8) and the Passive House Planning Package software. Results from that research indicate that MJ8 significantly oversizes heating systems for superinsulated homes and that thermal inertia and internal gains should be considered for more accurate load calculations.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Water Phase Change Heat Exchanger System Level Analysis for Low Lunar Orbit
In low Lunar orbit (LLO) the thermal environment is cyclic - extremely cold in the eclipse and as warm as room temperature near the subsolar point. Phase change material heat exchangers (PCHXs) are the best option for long term missions in these environments. The Orion spacecraft will use a n-pentadecane wax PCHX for its envisioned mission to LLO. Using water as a PCM material is attractive because its higher heat of fusion and greater density result in a lighter, more compact PCHX. To assess the use of a water PCHX for a human spacecraft in a circular LLO, a system level analysis was performed for the Orion spacecraft. Three cases were evaluated: 1) A one-to-one replacement of the wax PCHX on the internal thermal control loop with a water PCHX (including the appropriate control modifications), 2) reducing the radiator return setpoint temperature below Orion's value to enhance PCHX freezing, and 3) placing the water PCM on the external loop. The model showed that the water PCHX could not be used as a drop-in replacement for the wax PCHX. It did not freeze fully during the eclipse owing to its low freezing point. To obtain equivalent performance, 40% more radiator area than the Orion baseline was required. The study shows that, although water PCHXs are attractive at a component level, system level effects mean that they are not the best choice for LLO.
Navarro, Moses↗
An electrochemical system for efficiently harvesting low-grade heat energy
Capable and low-cost thermal energy-harvesting systems are necessary to utilize the tremendous low-grade heat sources. Although thermoelectric devices are attractive, its efficiency is limited by the relatively low figure-of-merit and low-temperature differential. An alternative method is to explore thermodynamic cycles. Thermogalvanic effect, the dependence of electrode potential on temperature, can construct such cycles. In one cycle, an electrochemical cell is charged at a temperature and then discharged at a different temperature with higher cell voltage, thereby converting heat to electricity. Here we report an electrochemical system using a copper hexacyanoferrate cathode and a Cu/Cu 2+ anode to convert heat into electricity. The electrode materials have low polarization, high charge capacity, moderate temperature coefficients and low specific heat. These features lead to a high heat-to-electricity energy conversion efficiency of 5.7% when cycled between 10 and 60 °C, opening a promising way to utilize low-grade heat.
25 ENERGY STORAGE↗
Modeling District Heating and Cooling Systems with URBANopt, GeoJSON to Modelica Translator, and the Modelica Buildings Library
The URBANopt project has successfully leveraged OpenStudio/EnergyPlus to model buildings and electrical systems at an urban scale; however, URBANopt has lacked the ability to model district thermal energy systems until recently. This paper will present the modeling infrastructure that was developed specifically for the analysis of district heating and cooling systems, and how it is integrated into the existing URBANopt framework. The paper also discusses the development of new models added to the Modelica Buildings Library to model various district energy system components including loads, energy transfer stations (ETS), distribution networks, and central plants. The paper describes how different building loads can be modeled including time series, TEASER reduced-order models, or Spawn of EnergyPlus models. URBANopt District Energy Systems allows the user to switch between the various configurations.
district heating and cooling↗
High-performance solar collector
Evacuated all-glass concentric tube collector using air or liquid transfer mediums is very efficient at high temperatures. Collector can directly drive existing heating systems that are presently driven by fossil fuel with relative ease of conversion and less expense than installation of complete solar heating systems.
Beekley, D. C.↗
Advanced two-phase heat transfer systems
Future large spacecraft, such as the Earth Observing System (EOS) platforms, will require a significantly more capable thermal control system than is possible with current 'passive' technology. Temperatures must be controlled much more tightly over a larger surface area. Numerous heat load sources will often be located inside the body of the spacecraft without a good view to space. Power levels and flux densities may be higher than can be accommodated with traditional technology. Integration and ground testing will almost certainly be much more difficult with such larger, more complex spacecraft. For these and similar reasons, the Goddard Space Flight Center (GSFC) has been developing a new, more capable thermal control technology called capillary pumped loops (CPL's). CPL's represent an evolutionary improvement over heat pipes; they can transport much greater quantities of heat over much longer distances and can serve numerous heat load sources. In addition, CPL's can be fabricated into large cold plates that can be held to tight thermal gradients. Development of this technology began in the early 1980's and is now reaching maturity. CPL's have recently been baselined for the EOS-AM platform (1997 launch) and the COMET spacecraft (1992 launch). This presentation describes this new technology and its applications. Most of the viewgraphs are self descriptive. For those that are less clear additional comments are provided.
Swanson, Theodore D.↗
Performance and Costs of Ductless Heat Pumps in Marine-Climate High-Performance Homes Habitat for Humanity The Woods
The Washington State University (WSU) Energy Program's Building America (BA) team conducted a case study of a high-performance affordable housing community: The Woods (Figure 1). This BA effort is part of a larger-scale study of 30 homes funded from 2013-2016 by Tacoma Public Utilities (TPU) and the Bonneville Power Administration. The Woods is a Habitat for Humanity (HFH) community of homes certified by ENERGY STAR Homes Northwest (ESHNW); the community is in the marine climate of Tacoma/Pierce County, Washington. This research report builds on an earlier preliminary draft 2014 BA report and includes significant billing analysis and cost-effectiveness research from a collaborative and ongoing DHP research effort for TPU and the Bonneville Power Administration. This final BA report focuses on the results of field testing, modeling, and monitoring of ductless mini-split heat pump hybrid heating systems in seven homes built and first occupied at various times between September 2013 and October 2014. The report also provides WSU documentation of high-performance home observations, lessons learned, and stakeholder recommendations for builders of affordable high-performance housing. The research goal of the U.S. Department of Energy's BA research team Building America Partnership for Improved Residential Construction was to compare a ductless heat pump (DHP) hybrid system (DHP in common area/electric resistance [ER] in bedrooms) to an all-electric zonal ER system in high-performance single-family affordable housing. This effort included assessing the costs and benefits of a DHP/ER hybrid system located in the main living area to offset the primary heating demand of zonal ER heaters in the bedroom zones and comparing these findings to data from of new affordable single-family housing in Washington State. This report includes: (1) Measured indoor and outdoor temperatures and relative humidity (RH) in the homes. (2) Field testing results of heating, ventilating, and air-conditioning equipment; ventilation system airflows; building envelope tightness; lighting, appliance, and other input data required for preliminary Building Energy Optimization (BEopt) modeling; and ENERGY STAR field verification (3) BEopt modeling results compared to measured energy use. (4) A comparison of the space heat energy consumption of a DHP/ER hybrid heating system and a traditional zonal ER heating system installed in the same home. This comparison is made by implementing a series of weekly "flip-flop tests" (referred to here as "switchback" tests per TPU) to compare space heating, temperature, and RH in zonal ER heating mode with a DHP/ER mode as discussed in the Building America Test Plan (Lubliner 2010a). (5) Cost data from HFH and other sources related to building efficiency measures focusing on the DHP/ER hybrid heating system. (6) An evaluation of the thermal performance and cost benefit of DHP/ER hybrid heating systems in these high-performance homes employing life cycle cost analysis for energy code policy and monthly cash flow analysis of HFH homeowners. (7) Post-monitoring occupant survey results. The report also provides the following stakeholder findings and recommendations: (1) DHP single-head systems at The Woods are cost-effective to new homebuyers of these high-performance all-electric homes. (2) Stakeholder education is needed on design, inspection, and commissioning; documentation is needed for heat recovery ventilation (HRV) and from ENERGY STAR builders, verifiers, and inspectors to help ensure that the houses meet the goal of "build tight, ventilate right." (3) A code gap in inspection and enforcement was identified that should be addressed by: (3a) Improving the fire marshal's approach to sprinkler attic piping freeze protection; (3b) Improving the maintenance of ceiling insulation continuity; and (3c) Educating the local building inspector on attic insulation inspection concerns that allow for maximizing design improveme...
affordable housing↗
Ground Source Geothermal District Heating and Cooling System
Ball State University converted its campus from a coal-fired steam boiler district heating system to a ground source heat pump geothermal district system that produces simultaneously hot water for heating and chilled water for cooling. This system will include the installation of 3,600 four hundred feet deep vertical closed loop boreholes making it the largest ground source geothermal district system in the country. The boreholes will act as heat exchangers and transfer heat by virtue of the earth’s ability to maintain an average temperature of 55 degree Fahrenheit. With growing international concern for global warming and the need to reduce worldwide carbon dioxide loading of the atmosphere geothermal is poised to provide the means to help reduce carbon dioxide emissions. The shift from burning coal to utilizing ground source geothermal will increase electrical consumption but an overall decrease in energy use and reduction in carbon dioxide output will be achieved. This achievement is a result of coupling the ground source geothermal boreholes with large heat pump chiller technology. The system provides the thermodynamic means to move large amounts of energy with limited energy input. Ball State University: http://cms.bsu.edu/About/Geothermal.aspx
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
An Innovative Very Low Thermal Power Waste Heat Recovery System for Thermal Control of Deep Space Missions: A Thermal Flask in Space
Future missions to deep space, such as those to the outer planets (Jupiter, Saturn, etc.), which would rely on solar photovoltaic power, would need extremely large solar arrays to produce sufficient power for their operations because solar intensity is so low at those locations. Hence any additional power that would be needed for thermal control is extremely limited. Previous deep space missions like Juno (to Jupiter) required almost 200 W of electrical power for thermal control. This is prohibitively large for many future mission concepts, and leads to them needing very large solar arrays. For Saturn, where the solar flux is 1/4th the flux at Jupiter, this would entail an extremely large increase in the solar array size to accommodate the need for thermal survival power, which would be prohibitively large in size and mass, and very expensive. Hence there is a need to come up with a thermal architecture and design options that would not need such prohibitively large thermal power levels. One solution relies on harvesting the pre-existing waste heat from all the heat dissipation that would be present from operation of electronics, instruments, etc. for their own functionality. For example, for a generic Saturn mission, the various electronics would already dissipate about 200 Watts of heat that is simply "thrown away" to space from the spacecraft surfaces. The amount of thermal power that would be required for the safe thermal control of components within the spacecraft in deep space would be roughly of this magnitude for this class of spacecraft. So it makes good sense to try to harvest the waste heat and employ it to maintain the temperatures of all the components within their allowable limits. In particular, propulsion systems typically need to be kept above their freezing limits, around room temperature (15 C). Electronics needs to be kept typically above -40 C and batteries above -20 C. The next question becomes how to harvest this waste heat and direct it to the components that would need it for their survival. The proposed system utilizes a mechanically pumped, single phase fluid loop to pick up the waste heat from components attached to this loop's tubing and then directed to a thermal flask that has tubing attached to it. The thermal flask is cylindrically shaped and contains essentially all systems and components in the spacecraft within it, with the exception of the solar array, antennae, thrusters and various apertures of instruments, etc. to allow them an unobstructed view of space. Waste heat from the heat-dissipating components warms up the fluid and is carried to the flask surface and deposited on it via the fluid loop's flow. The entire flask is covered with Multi-Layered Insulation (MLI) to minimize the heat loss from the flask and allow it to remain warm. Hence the flask essentially creates a thermal environment within which the spacecraft components reside. The temperature of the components within the flask is then essentially the same as the temperature of the flask. This approach could be a very enabling feature for deep space missions. This paper describes the approach utilized for this thermal architecture, along with its mechanical and implementation aspects. Additionally it will compare and contrast this approach with the more conventional solutions utilized earlier.
Bhandari, Pradeep↗
Thermal protection system gap heating rates of the Rockwell International flat plate heat transfer model (OH2A/OH2B)
Heat transfer data for the Rockwell International Flat Plate Thermocouple Model are presented. The model simulated the Space Shuttle Vehicle Thermal Protection System. Data were recorded for locations in and around various size gaps for various gap orientation configurations. The test was conducted at Mach 5.1 for free-stream Reynolds number per foot values from 500,000 to 1,500,000.
Foster, T. F.↗
Economical solar-heating for homes
Do-it-yourself supplementary solar-heating system is available for purchase at approximately $2,000. Report describes design, construction, testing, and economic analysis of low-cost solar heating system.
Allred, J. W.↗