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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 181 records · Page 10

Thermal Insulation for a High Temperature Molten Salt Storage Tank in a CSP Plant

A ternary molten chloride has been suggested as a high temperature (550-720 °C) sensible heat storage medium for a two-tank system. An effective thermal insulation is proposed to provide an opportunity for the fabrication of both the hot and cold storage tanks from lower cost metals, e.g. A240-347H, by maintaining the tank wall below 500 °C. To achieve this, the hot storage tank mainly comprises of inner shell (11.4 cm of a refractory brick as liner (KX-99®), 30 cm of insulation brick) and outer metal shell, where 5 cm of frozen layer of PCM800 (NaCl), and 5 cm of ceramic wool fill the annular space between the shells. Another layer of ceramic wool was introduced at the outer side of the metal shell to keep the temperature lower than 60 °C. ANSYS Fluent was used for the numerical study of the cool down behavior of the system during idle period when tank is quarter-filled. The heat transfer modes were considered as radiation and natural convection heat transfer from the hot molten salt at 720 °C, conduction through the solid layers and convection heat transfer from the outer shell to the environment at 15 °C. The results showed that the proposed insulation system including a frozen layer of PCM800 maintains the temperature at the metal wall lower than 500 °C, and lower than 60°C at the outer side of the tank. Apart from the insulation property of the frozen layer of PCM800, it absorbs any leak of hot molten salt, acting as a barrier between salt and the metal shell. The thermal performance analysis provide an insight into the benefits of the multilayer insulation.

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

Materials Data on CsP(HO2)2 by Materials Project

CsH2PO4 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.29 Å. P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.54 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a linear geometry to two equivalent O2- atoms. Both H–O bond lengths are 1.20 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+, one P5+, and one H1+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom.

36 MATERIALS SCIENCE↗

Materials Data on CsP(HO2)2 by Materials Project

CsH2PO4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 3.16–3.31 Å. P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.55 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.04 Å) and one longer (1.49 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one P5+, and one H1+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom.

36 MATERIALS SCIENCE↗

Materials Data on CsP(HO2)2 by Materials Project

CsH2PO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 3.14–3.32 Å. P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.58 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.05 Å) and one longer (1.48 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one P5+, and one H1+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cs1+, one P5+, and one H1+ atom.

36 MATERIALS SCIENCE↗

Research and Development for Novel Thermal Energy Storage Systems (TES) for Concentrating Solar Power (CSP)

The overall objective was to develop innovative heat transfer devices and methodologies for novel thermal energy storage systems for concentrating solar power generation involving phase change materials (PCMs). Specific objectives included embedding thermosyphons and/or heat pipes (TS/HPs) within appropriate phase change materials to significantly reduce thermal resistances within the thermal energy storage system of a large-scale concentrating solar power plant and, in turn, improve performance of the plant. Experimental, system level and detailed comprehensive modeling approaches were taken to investigate the effect of adding TS/HPs on the performance of latent heat thermal energy storage (LHTES) systems.

14 SOLAR ENERGY↗

Brayton-Cycle Baseload Power Tower CSP System

The primary objectives of Phase 2 of this Project were:1. Engineer, fabricate, and conduct preliminary testing on a low-pressure, air-heating solar receiver capable of powering a microturbine system to produce 300kWe while the sun is shining while simultaneously storing enough energy thermally to power the system for up to 13 hours thereafter. 2. Cycle-test a high-temperature super alloy, Haynes HR214, to determine its efficacy for the system’s high-temperature heat exchanger. 3. Engineer the thermal energy storage system. This Phase 2 followed Wilson’s Phase 1, which primarily was an engineering feasibility study to determine a practical and innovative approach to a full Brayton-cycle system configuration that could meet DOE’s targets. Below is a summary table of the DOE targets with Wilson’s Phase 1 Project results. The results showed that a Brayton system with an innovative (low pressure) solar receiver with ~13 hours of dry (i.e., not phase change materials or molten salts but rather firebrick, stone, or ceramics) has the potential to meet or exceed DOE targets. Such systems would consist of pre-engineered, standardized, factory-produced modules to minimize on-site costs while driving down costs through mass production. System sizes most carefully analyzed were in the range of 300 kWe to 2 MWe. Such systems would also use off-the-shelf towers, blowers, piping, microturbine packages, and heliostats. Per DOE’s instructions, LCOEs are based on the elevation and DNI levels of Daggett, CA, for a 100 MWe power plant following 2 GWe of factory production of the various system components.

14 SOLAR ENERGY↗

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↗

Development of a High-Efficiency Hybrid Dry Cooler System for sCO 2 Power Cycles in CSP Applications

This project addressed a major gap in supercritical CO 2 (sCO 2 ) power cycle research by focusing on the pre-cooler, a component that had received little attention despite its significant impact on cycle efficiency and plant economics. The team developed a compact dry cooler using brazed/diffusion-bonded microchannel passages paired with formed air-side fins, advancing the technology from TRL-2 toward commercial readiness. Compared to conventional fin-tube coolers, the design cuts installation footprint by roughly half for 10+ MWth systems while achieving better heat transfer and lower approach temperatures, translating into a projected LCOE reduction from 6.04 ¢/kWh to between 5.85 and 5.94 ¢/kWh. While fabrication of an aluminum MW-scale prototype revealed brazing and sealing challenges at larger scales, lessons learned informed a subsequent 1 MWth unit that was successfully built and delivered for integration into Sandia's Gen3 Particle Pilot Plant, advancing the technology to TRL-7 with a path toward TRL-8 pending successful testing.

30 DIRECT ENERGY CONVERSION↗

Development and Validation of Low-Cost, High-Reflectance Composite CSP Facets: SIPS Final Report

This work investigates the various challenges associated with developing heliostat structural composite facets using 1 mm glass mirrors. Such facets are desirable for Concentrating Solar Power because 1 mm glass mirrors provide an absolute increase in reflectivity of 2-3 % over the industry standard of 4 mm glass mirrors. Prototypes of paraboloid composite facets with 1 mm glass mirrors were constructed that have a root mean square slope error on the order of 2 mrad while achieving greater than 96% reflectivity. These facets were constructed using a low-quality aluminum mold and a bill of materials that show potential to achieve cost parity with existing 4 mm glass mirrors supported by structural steel. The facets produced were able to survive up to 50 mm hail ball impacts and were robust against accelerated environmental cycling designed to expose durability concerns. Further work is needed to develop a scalable and cost-effective manufacturing process with a similar bill of materials.

14 SOLAR ENERGY↗

Effect of thermal cycling ramp rate on CSP assembly reliability

A JPL-led chip scale package consortium of enterprises recently joined together to pool in-kind resources for developing the quality and reliability of chip scale packages for a variety of projects. The experience of the consortium in building more than 150 test vehicle assemblies, single and double sided multilayer PWBs, and the environmental test results has now been published as a chip scale package guidelines document.

accelerated thermal cycle chip scale package solde↗

Manufacturing Robustness of CSP in SMT Line

In this paper, the assembly process flow, solder paste for different stencil design, manufacturing defects, X-ray inspection results, and ultrasonic characterizations are reported.

electronic assembly SMT CSP fine pitch microvia te↗