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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

A Techno-Economic Analysis of a 50MWth Light-Trapping Cavity-Planar Solar Receiver Tower Capital Expenditures and its Cost Mitigation Strategies

To maximize thermal efficiency, the National Renewable Energy Laboratory (NREL) has proposed a light-trapping cavity-planar receiver design intended to capture energy from reradiating surfaces. This system implements a macroscale light trapping mechanism induced by panels with triangular channels, this mechanism allows for elevated temperatures on the receiver panels and in turn the temperature of the HTF; using this design coupled with the implementation of a fluidized particle flow as the HTF, it can be expected for some components to reach a peak working temperature of nearly 1000 degrees C cyclically throughout each day-night cycle. While these temperatures correlate to higher efficiency of the CSP tower they also demand intense thermomechanical properties from the materials used to make the receiver panels. In this analysis, we will list our assumptions to provide clarity on the significance of our calculation. This cost analysis will be conducted using a combination of both case study data and surveying industry to determine costs that are relevant to the current market trends. This analysis represents an early attempt to establish the Capital Expenditures required for a CSP tower of such design to determine the feasibility of implementing such a system in the industry.

concentrated solar power (CSP)↗
NASA NTRS2006

Orbiting GPS Receiver Modified to Track New L2C Signal

The L2C signal is a great step forward for civil applications of GPS, enabling high-accuracy dual-frequency measurements. Engineers from the Jet Propulsion Laboratory and ITT teamed to reprogram FPGA firmware and add tracking software on an orbiting receiver to track the new GPS L2C signal from SAC-C. SAC-C is an Argentinean science satellite and was launched in November 2000 with a BlackJack GPS receiver. This is a dual-frequency digital receiver with 48 tracking channels and four antennas. On SAC-C, it provides precise orbits, atmospheric occultation data, tests of GPS surface reflections, and serves as an orbiting test bed for new GPS development such as the L2C tracking reported here.

GPS receiver↗
DOE OSTI2026

Modeling and Experimental Demonstration of Flux Spreading in Light Trapping Planar-Cavity Solar Enclosed Particle Receivers

This study experimentally validates and numerically models the flux-spreading effect in a light-trapping planar-cavity solar receiver) for particle-based concentrating solar power systems. The receiver's shallow cavity with vertical planar walls redistributes concentrated solar flux, reducing peak intensity and achieving uniform heat flux. On-sun tests at National Renewable Energy Laboratory's High-Flux Solar Furnace under flux up to 1500 kW/m2 measured cavity wall temperatures, which were compared with Monte Carlo ray-tracing (SolTrace) and computational numerical simulations. Three angular absorptance models were evaluated: constant absorptance, a Pyromark-based directional model, and a Fresnel-based Cr2O3 model. The Fresnel-derived model showed the best agreement with experiments, achieving high correlation (PC > 0.85), structural similarity (SSIM > 0.98), and signal-to-noise ratios (PSNR > 40 dB), with temperature prediction errors of 1-11%. Results confirm that flux spreading mitigates local overheating and validate the integrated modeling approach, supporting the solar receiver scalability for high-efficiency, high-temperature concentrating solar power applications.

14 SOLAR ENERGY↗
DOE OSTI2024

Development of Ti 3 SiC 2 MAX phase tubular structures for solar receiver applications

Solar receiver tubes are key components of concentrating solar-thermal power (CSP) systems that harvest solar energy. For better efficiency, the Gen3 CSP receivers, which collect heat into a heat transfer fluid, require a temperature exceeding 700 °C during operation and need to perform under extreme conditions of high temperature and high thermal stress. Operators are seeking CSP designs using new high-temperature structural materials with high thermal conductivity and high creep resistance to achieve a design life of 30 years and thus help recover the plant capital cost sooner. MAX phase materials, which consist of an early transition metal element, an A-group element, and carbon or nitrogen, are expected to exhibit high creep resistance as well as high fracture toughness. Here, in this paper, we describe fabricating both (1) dense Ti 3 SiC 2 MAX phase disks and (2) short-length tubes using field-assisted sintering technology (FAST). First, the disk samples that we fabricated are fully dense and contain ≈90 % Ti 3 SiC 2 MAX phase materials and ≈10 % TiC phase materials. We determined a flexure strength of 519 ± 32 MPa by conducting a four-point bending test at room temperature with rectangular bar samples of ≈100 % density. The thermal conductivity of the Ti 3 SiC 2 MAX phase samples, measured by light flashing analysis, decreases linearly from a value of 41 W . m -1 . K -1 at room temperature to a value of 36 W . m -1 . K -1 at 650 °C. A solar reflectance measurement of the Ti 3 SiC 2 MAX phase revealed that, temperature increases from 400 to 1400 °C, thermal emittance increases from 0.39 to 0.49, while selectivity decreases from 1.8 to 1.4, respectively. Whereas the surface oxidized MAX phase samples after 100 h exposure to air at 1000 °C exhibit that of SiC. Next, we discuss fabrication of the crack-free Ti 3 SiC 2 MAX phase tubular structures accomplished by using FAST processing in graphite bedding. A Ti 3 SiC 2 MAX phase content of > 95 % with traceable ≈3% remaining TiC phase and ≈15 % porosity were demonstrated after high-temperature annealing. An average fracture strength of ≈250 MPa was determined with Ti 3 SiC 2 MAX phase tubes of ≈85 % density by diametral compression testing at room temperature. Our work demonstrated that using FAST processing to produce Ti 3 SiC 2 MAX phase tubular structures for CSP receiver applications is a viable approach.

14 SOLAR ENERGY↗
DOE OSTI2022

Molten Salt vs. Liquid Sodium Receiver Selection Using the Analytic Hierarchy Process

An international team led by NREL analyzed the favorability of two alternative liquid receiver designs for a 700+ degrees C receiver under the Gen3 CSP Liquid Pathway project. The competing liquid heat transfer fluids were a ternary chloride salt and liquid-metal sodium. The team applied a facilitated analytic hierarchy process (AHP) to arrive at a recommended alternative and set a path forward for the project. The AHP criteria were formulated, weighted, and scored by the project leadership team and technical advisory committee consisting of energy industry and CSP experts. The six- month process culminated with a two-day workshop where the sodium alternative was deemed to have both a significantly higher benefit (19.3%) and a lower LCOE (11.4%), with only a slightly higher risk (~3%) than the salt alternative. Consequently, a sodium-receiver design was selected for the Liquid Pathway project, where it will be used to charge a two- tank chloride salt thermal energy storage system.

analytic hierarchy process↗
DOE OSTI2023

Performance Assessment of Pakistani Central Receiver Plant Case Study Using Aimpoint Strategy Optimization Tools

Pakistan has a high potential for both photovoltaic and Concentrated Solar Power (CSP) deployment to meet its energy requirements. Previous feasibility studies have shown that a variety of CSP technologies are both technically and economically viable in the Pakistani climate and can significantly mitigate the country's current lack of grid reliability. This work aims to enhance the performance of a previously designed Central Receiver System (CRS) plant for Pakistan using state-of-the-art aimpoint optimization methods. Results from our case study show that optimized aiming strategies have increased practicality due to their adherence to flux limitations on the receiver, and offer ~2.4% more thermal energy delivered to the receiver for the Pakistani case study compared to modern performance characterization software, translating to up to 149 additional hours of nameplate-capacity production to address the shortfall in an electricity-starved market.

central receiver system↗
DOE OSTI2023

Helical Fins for Concentrated Solar Receivers: Design Optimization and Entropy Analysis

Concentrated solar power (CSP) with thermal energy storage (TES) has the potential to achieve grid parity. This can be realized by operating CSP systems at temperatures above 700 °C with high-efficiency sCO 2 power cycles. However, operating CSP systems at such temperatures poses several challenges, among which the design of solar receivers to accommodate increased thermal loads is critical. To this end, this work explores and optimizes various swirl-inducing internal fin designs for solar receiver tubes. These fin designs not only improve the thermal performance of receiver tubes but also levelize temperature unevenness caused by non-uniform thermal loading. In this work, the geometric parameters of the fin designs are optimized to maximize the Nusselt number with a constraint on the friction factor. This optimization, however, is computationally intensive, requiring hundreds of simulation calls to computational fluid dynamics (CFD) models. Here, to circumvent this problem, surrogate models are used to approximate the simulation outputs needed during the optimization. In addition, this study also examines the fin designs from an entropy generation perspective. To this end, the entropy contributions from thermal and viscous effects are quantitatively compared while varying the operational Reynolds number.

14 SOLAR ENERGY↗
DOE OSTI2021

Robust and Spectrally Selective Aerogels for Solar Receivers

The development of next generation concentrated solar thermal (CST) plants requires solar receivers to reach high temperatures (> 600°C) while minimizing costs. Efficiently generating such high temperatures using a line-focusing collector and an air-stable receiver has the potential to change the current CSP paradigm because it would: (1) result in large improvements in system-level efficiency of line-focusing systems by enabling the use of high-efficiency supercritical CO 2 power cycles; (2) decrease the LCOE of line-focusing systems to meet SETO 2030 goals; (3) maintain performance over the lifetime of the CSP plant by avoiding issues related to breakdown of vacuum. The use of aerogels as transparent insulating materials (TIMs) in solar thermal receivers has the potential to enable such improvements. Specifically, aerogels can be placed in front of a black (or partially selective) high-temperature absorber to allow sunlight to transmit to the absorber but block heat from escaping. These materials can improve the efficiency and simplify the complexity of thermal transport systems by enabling operation at moderate or no vacuum levels. These potential benefits have been explicitly identified by SETO as ‘high impact’. The use of mesoporous silica as a TIM has already led to large improvements in solar collection efficiency. Nevertheless, these materials inherently lose structural integrity and the ability to suppress radiation losses at high temperatures. Here, we address these challenges by leveraging 1-cycle atomic layer deposition of aluminum oxide onto a silica aerogel to form a thermally stable interfacial layer that is transparent to sunlight but broadly absorbs in the mid-infrared. This interfacial absorption results in a two-fold reduction in measured heat losses from an absorber at 700°C and solar thermal efficiency of 81% at 700°C under 60 Suns, based on measurements of heat loss and solar transmittance. Extended-duration heat treatment reveals that the multicomponent aerogel is stable at high temperatures relative to a silica aerogel. Furthermore, we experimentally demonstrate the concept of using infrared plasmon resonances to selectively enhance the thermal absorption coefficient of TIMs in order to strongly suppress thermal radiative losses at high temperatures. We term this mechanism plasmon-enhanced greenhouse selectivity (PEGS). Unlike silica aerogels, where much of the IR absorption is lost at high temperatures, local surface plasmon resonances (LSPRs) in doped oxide nanoparticles overlap a significant portion of the blackbody spectrum and are maintained at high temperatures. Overall, this work paves the way for next-generation solar thermal energy using thermally robust transparent insulating materials.

14 SOLAR ENERGY↗
DOE OSTI2020

Robust and Spectrally Selective Aerogels for Solar Receivers (Final Technical Report)

The development of next generation concentrated solar thermal (CST) plants requires solar receivers to reach high temperatures (> 600°C) while minimizing costs. Efficiently generating such high temperatures using a line-focusing collector and an air-stable receiver has the potential to change the current CSP paradigm because it would: (1) result in large improvements in system-level efficiency of line-focusing systems by enabling the use of high-efficiency supercritical CO2 power cycles; (2) decrease the LCOE of line-focusing systems to meet SETO 2030 goals; (3) maintain performance over the lifetime of the CSP plant by avoiding issues related to breakdown of vacuum. The use of aerogels as transparent insulating materials (TIMs) in solar thermal receivers has the potential to enable such improvements. Specifically, aerogels can be placed in front of a black (or partially selective) high-temperature absorber to allow sunlight to transmit to the absorber but block heat from escaping. These materials can improve the efficiency and simplify the complexity of thermal transport systems by enabling operation at moderate or no vacuum levels. These potential benefits have been explicitly identified by SETO as ‘high impact’. The use of mesoporous silica as a TIM has already led to large improvements in solar collection efficiency. Nevertheless, these materials inherently lose structural integrity and the ability to suppress radiation losses at high temperatures. Here, we address these challenges by leveraging 1-cycle atomic layer deposition of aluminum oxide onto a silica aerogel to form a thermally stable interfacial layer that is transparent to sunlight but broadly absorbs in the mid-infrared. This interfacial absorption results in a two-fold reduction in measured heat losses from an absorber at 700°C and solar thermal efficiency of 81% at 700°C under 60 Suns, based on measurements of heat loss and solar transmittance. Extended-duration heat treatment reveals that the multicomponent aerogel is stable at high temperatures relative to a silica aerogel. Furthermore, we experimentally demonstrate the concept of using infrared plasmon resonances to selectively enhance the thermal absorption coefficient of TIMs in order to strongly suppress thermal radiative losses at high temperatures. We term this mechanism plasmon-enhanced greenhouse selectivity (PEGS). Unlike silica aerogels, where much of the IR absorption is lost at high temperatures, local surface plasmon resonances (LSPRs) in doped oxide nanoparticles overlap a significant portion of the blackbody spectrum and are maintained at high temperatures. Overall, this work paves the way for next-generation solar thermal energy using thermally robust transparent insulating materials.

14 SOLAR ENERGY↗
DOE OSTI2025

Design Basis Document / Owner’s Technical Specification for Nitrate Salt Systems in CSP Projects: Volume 1 Specifications for Parabolic Trough Projects, Volume 2 - Specifications for Central Receiver Projects, Volume 3 - Narrative

Design Basis Documents / Owner’s Technical Specifications are developed for parabolic trough and central receiver power plants using nitrate salt as the heat transport fluid and the thermal storage medium. The goals were to 1) distill the successful experience with nitrate salt systems from as many commercial projects as possible, 2) provide technical bases for equipment design/selection that an owner can impose on an EPC contractor, 3) compile this information in one location to provide guidance on salt systems that is as broadly applicable to as many projects as possible, and 4) work toward an industry consensus on a Design Basis Document that reflects the lessons learned from earlier commercial projects. The document allows an owner to provide design guidance, and to impose a minimum set of requirements, above and beyond those in the normal Codes and Standards, on an EPC contractor in an effort to avoid a repeat of past mistakes. If successful, this would allow salt systems to achieve the same levels of reliability and availability as commercial parabolic trough plants using diphenyl oxide / biphenyl (i.e., Dowtherm A, Therminol VP-1) as the heat transfer fluid. The report consists of 3 volumes: • Volume 1 - Specifications for Parabolic Trough Projects • Volume 2 - Specifications for Central Receiver Projects • Volume 3 - Narrative Volumes 1 and 2 include discussions of the following topics: • Plant functional requirements for the salt systems • Plant operating states, and transitions between states, for the salt systems • Risk analysis of the principal salt components • Plant requirements for the salt systems to meet the functional and the operating requirements • Type of specification for the principal salt components: functional; or prescriptive • Current state of the art for salt systems. Volume 3 discusses a number of cases in which the salt equipment at commercial parabolic trough and central receiver projects has not met the projected levels of reliability and availability. Possible reasons for the sources of the problems are discussed, as is a range of possible alternate designs that could avoid the known problems.

14 SOLAR ENERGY↗
DOE OSTI2021

Techno-Economic Optimization of CSP Plants with Free-Falling Particle Receivers

Particle receivers are one of the candidates for the next generation of CSP plants, whose goal is to reduce the levelized cost of electricity (LCOE) to 0.05 $/kWh. This paper presents a techno-economic analysis to study if a CSP system with free-falling particle receiver can achieve this goal. The plant analyzed integrates two ground-based bins to store the excess energy and a supercritical CO2 cycle to generate electricity. The model used for the analysis presents several upgrades to previous particle systems models in order to increase its fidelity, accuracy, and representativeness of an actual system. The main upgrades are the addition of off-design conditions during the annual simulations in all the components and an improved receiver model validated against CFD simulations. The size of the main components is optimized to obtain the system configuration with minimum LCOE. The results show that particle CSP systems can reduce the LCOE to 0.056 $/kWh if the configuration is composed of 1.61 × 106 m2 of heliostats, a 250 m high tower with a 537 m2 falling particle curtain, and 16 h thermal energy storage.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1963

The ground transmitter and receiver

Ground station equipment for the Telstar experiment includes a 6-kmc transmitter and a 4-kmc receiver used for television and telephone channels. This paper describes the over-all transmitting and receiving arrangements and presents detailed accounts of the RF and power-supply subsystems. Information is also presented on protection, control and equipment features, and on receiver noise performance.

TRANSMITTER↗
NASA NTRS1966

Theory and Practical Design of Phase-locked Receivers, Volume I

This is Volume I of a two-volume work on the theory, of phase-locked receivers, with pertinent reference material on practical receiver design. Volume I is primarily devoted to the performance of carrier-tracking loops, including a rigorous treatment of narrow-band systems having IF limiters. The bulk of the work is based on a theoretical linear model, but a nonlinear method is also presented to predict behavior near the threshold. The emphasis throughout the work is toward completeness, simplicity, and internal consistency of the material assembled. Part I of this Volume is an exposition of the theory, the resulting equations, and the design philosophy that have enabled the phase-lock concept to evolve into the basic principle underlying the most sensitive receivers il, the world today. Part II is a condensed version of Part I, intended as a quick reference to formulas, definitions, and salient design considerations.

RECEIVER↗
NASA NTRS2004

From BlackJack to GOX: the transfer, test, and validation of the ROCSat-3 GPS occultation receiver

ROCSat-3's primary instrument is the GPS Occultation Receiver (GOX) and is based on the Jet Propulsion Laboratory's (JPL) proven BlackJack GPS Receiver. The COSMIC GOX receivers will demonstrate an important new operational data type for near-real-time assimilation into weather models by providing over 2500 atmospheric profiles per day with a global distribution.

GPS Occultation Receiver↗
NASA NTRS2006

Mars Reconnaissance Orbiter, Ground Data System, Receivables and Deliverables (REC/DELs)

This paper presents one JPL element manager's approach to describe a complex Ground Data System (GDS) with its receivables and deliverables (REC/DEL). The Mars Reconnaissance Orbiter (MRO) Ground Data System is the integrated set of ground software, hardware, facilities and networks that support mission operation. REC/DEL is a powerful tool for specifying hierarchy of commitments among systems and teams. Receivable of a system is a deliverable of another system. Focusing on tangible products enables the manager to objectively measure progress in a schedule. Jet Propulsion Laboratory mandates the use of REC/DEL for flight projects. Tutorial and training is provided for managers to create integrated REC/DEL database using automated systems. Project schedules are based on REC/DELs. This paper is not focusing on the mechanics of REC/DEL database creation, but it provides a guideline how one systematically creates categories of deliverables and receivables for ground data system components.

guidelines↗
NASA NTRS2006

Mars Reconnaissance Orbiter, Ground Data System, Receivables and Deliverables (REC/DELs)

This paper presents one JPL element manager's approach to describe a complex Ground Data System (GDS) with its receivables and deliverables (REC/DEL). The Mars Reconnaissance Orbiter (MRO) Ground Data System is the integrated set of ground software, hardware, facilities and networks that support mission operation. REC/DEL is a powerful tool for specifying hierarchy of commitments among systems and teams. Receivable of a system is a deliverable of another system. Focusing on tangible products enables the manager to objectively measure progress in a schedule. The Jet Propulsion Laboratory mandates the use of REC/DEL for flight projects. Tutorial and training is provided for managers to create an integrated REC/DEL database using automated systems. Project schedules are based on REC/DELs. This paper is not focusing on the mechanics of REC/DEL database creation, but it provides a guideline how one systematically creates categories of deliverables and receivables for ground data system components...

ground data system (GDS)↗
NASA NTRS2012

Experimental Evaluation of the "Polished Panel Optical Receiver" Concept on the Deep Space Network's 34 Meter Antenna

The potential development of large aperture ground-based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation proposes to polish the aluminum reflector panels of 34-meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by even state-of-the-art polished aluminum panels. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. A custom designed aluminum panel has been mounted on the 34 meter research antenna at Deep-Space Station 13 (DSS-13), and a remotely controlled CCD camera with a large CCD sensor in a weather-proof container has been installed next to the subreflector, pointed directly at the custom polished panel. Using the planet Jupiter as the optical point-source, the point-spread function (PSF) generated by the polished panel has been characterized, the array data processed to determine the center of the intensity distribution, and expected communications performance of the proposed polished panel optical receiver has been evaluated.

photon counting detection↗
NASA NTRS2014

Design of a K/Q-band Beacon Receiver for the Alphasat TDP#5 Experiment

This paper describes the design and performance of a coherent K/Q-band (20/40GHz) beacon receiver developed at NASA Glenn Research Center (GRC) that will be installed at the Politecnico di Milano (POLIMI) for use in the Alphasat Technology Demonstration Payload #5 (TDP#5) beacon experiment. The goal of this experiment is to characterize rain fade attenuation at 40GHz to improve the performance of existing statistical rain attenuation models in the Q-band. The ground terminal developed by NASA GRC utilizes an FFT-based frequency estimation receiver capable of characterizing total path attenuation effects due to gaseous absorption, clouds, rain, and scintillation. The receiver system has been characterized in the lab and demonstrates a system dynamic range performance of better than 58dB at 1Hz and better than 48dB at 10Hz rates.

beacon receiver↗