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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 1,729 records · Page 96
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

TECHNO-ECONOMIC ANALYSIS OF A CRYOGENIC FLUX CAPACITOR FOR GRID STORAGE

The Cryogenic Flux Capacitor (CFC) is a cold, dense fluid storage core with integrated design features that afford the designer flexibility and provide new possibilities for the storage and discharge of energy. The stored energy, in this case, is represented by hydrogen physically bonded within the nanoscale pores within the aerogel composite blanket material, and the process of bonding or debonding is governed by principles of physical adsorption (physisorption) and thermodynamics. The large surface area afforded by the nanoporous aerogel (~1,000 m2/g) allows for storage densities close to, or in some cases exceeding, that of normal boiling point liquids. Its performance easily exceeds what can be achieved via ambient temperature, high-pressure gas storage for an equivalent volume. CFC storage is predicted to be easily scalable, is constructed from readily available commercial materials, lends itself to a range of pressure applications, and is geometry insensitive.

Joshua Schmitt↗
NASA NTRSDate not supplied

Economical Third-Order Methods for Accurate Surface Heating Predictions on Simplex Element Meshes

A node-centered edge-based finite volume discretization of the compressible Navier-Stokes equations is presented with the heat flux reformulated as a first order system. A dissipation vector is derived for the reformulated system, such that the heat flux can be upgraded to O(h^3) on simplex element meshes in the same fashion as the inviscid fluxes. The method of manufactured solutions is used to demonstrate this uniform order property in heat flux. This new system is shown to efficiently produce accurate surface heating predictions on hypersonic hemisphere flow using an anisotropic simplex element mesh, achieving O(h^3) accuracy at relatively low computational cost compared to similar methods.

Computational Fluid Dynamics↗
NASA NTRS2024

Detection and Socio-Economic Attribution of Groundwater Depletion in India

Groundwater is a critical resource for both consumption and food security in India, where groundwater management faces significant challenges due to climate change and anthropogenic activities. Although several studies explored groundwater variability in India, few have focused on the socioeconomic attribution of these changes, utilizing data from industries, population and water demand. In this study, trends in groundwater storage were examined by leveraging the largest in situ dataset ever collated in India from ~27,000 groundwater wells, satellite-based terrestrial-water-storage estimates, and hydrological model simulations. Five major hotspots of groundwater depletion across India were identified using in situ measurements and previously untapped socioeconomic datasets to attribute these trends. Approximately 16% of Indian groundwater monitoring stations exhibited systematically decreasing trends in groundwater levels. These hotspots are primarily concentrated in the northern and northwestern parts of India as well as in the states of Chhattisgarh, West Bengal, and Kerala. The north/northwestern hotspots have experienced a staggering loss of ~6.46 × 10^10 m3 of water over the past two decades. The factors contributing to this depletion include population growth, rapid urbanization, proliferation of factories and the expansion of agriculture.

Gautam Kunwar↗
DOE OSTI2020

Sustainability, Feasibility, and Economics of a Fuel Cell-Powered Data Center

Data centers, used for cloud computing or data storage, consume huge amounts of power and are increasing rapidly in number, and consequently, this increase in power consumption has raised concerns with green and sustainable energy supplies to minimize carbon emissions. Significant renewable power can be a carbon-free energy source to reduce the carbon footprint of a data center; however, direct integration of wind and solar power with data center causes concern of the power quality for uninterrupted power supply to computer servers. The reliable power supply can be accomplished by using power produced from fuel cells fueled by hydrogen. If fed with hydrogen derived from renewable sources, fuel cells will realize carbon-free data centers. This presentation shows various renewable-integration scenarios to meet reliable and sustainable power requirements for a data center.

25 ENERGY STORAGE↗
DOE OSTI2020

Techno-Economic Analysis of Integrated Gasification Fuel Cell Systems

This is a presentation that was delivered virtually at the 2020 International Pittsburgh Coal Conference. In the presentation, details of the cost and performance parameter improvement due to incremental changes made in gasification and fuel cell operation and system configurations were presented. High level results indicate that SOFC fueled by coal-derived synthesis gas can be competitive with other fossil-based energy generation technologies when significant improvement to gasification technology is made and carbon capture is included. The cost of carbon capture of this system is very low due to the high efficiency of the SOFC and the high system fuel utilization due to the vent gas recirculation concept which recirculates hydrogen in the effluent back to the cell.

Noring, Alex↗
DOE OSTI2020

Scenario Creation and Power-Conditioning Strategies for Operating Power Grids with Two-Stage Stochastic Economic Dispatch: Preprint

A significant difficultly associated with the use of stochastic programming to solve optimal power flow problems on a 5-minute timescale is the quality of renewable energy scenarios input by the user. This is especially true when considering power systems with high penetrations of renewable energy, e.g. wind power. This paper introduces the use of stochastic programming to solve the DCOPF problem with scenarios drawn directly from high-fidelity data sets. Hence, the proposed method avoids the problem of lost physics by finding high-fidelity analogs that can describe future states of the system. Furthermore, this method can be simply extended to output multi-period scenarios to the stochastic program. We demonstrate the effectiveness of this technique on simulated dispatch operations of the RTS-GMLC over a week.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Pumped Thermal Energy Storage: Thermodynamics and Economics

This presentation gives an overview of Pumped Thermal Energy Storage (PTES), and in particular concentrates on the performance and cost of a Joule-Brayton cycle with liquid storage. Results for systems with supercritical CO2 are also presented. PTES may be hybridized with solar heat, and some examples are provided as well as an overview of potential issues.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2021

Towards a Techno-Economic Analysis of PCM Integrated Hybrid HVAC Systems

Thermal end uses dominate building energy consumption and are a major driver of peak demand. As heating is electrified, peak electrical power required will surge, prompting a need for innovative HVAC system designs and controls.These designs must incorporate novel technologies at the component level and new integration techniques at the system level. One such possibility involves the addition of thermal energy storage (TES) in heating and cooling equipment using a phase change material (PCM) heat exchanger. Here, thermal energy storage via phase change can be used to shift the HVAC system loads to times of lower electricity cost, reduced carbon intensity, and greater energy efficiency. Most of the current utilization of PCM in buildings involves passive components. By actively controlling when heat is stored and released from PCM, we can optimize the building HVAC system to cost-effectively meet consumer needs with the flexibility to draw on renewable energy resources when they are abundant and available. While this combination of technologies is promising in theory, simulation-based evaluation of a prototype can be difficult due to the modeling requirements at the component level and the large number of possible configurations and operating modes at the system level. To conduct this evaluation, we use the Modelica language for modeling and simulation because it enables users to represent the important physics of the problem, interchange and rearrange components in an efficient manner, and implement a range of control configurations. In this work, we considered three case studies: a portable building, a large commercial retail store, and a multifamily residential apartment unit. Each of these employs a different system design, ranging from a single package vertical unit incorporating PCM to a central plant with independent heat pump, evaporative cooling, and thermal energy storage components. This paper describes the technologies in question, presents modeling at the component and system levels, and demonstrates building energy and demand charge cost savings with local time-of-use tariffs in a hot-dry climate.

Helmns, Dre↗