Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “co2”

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
DOE OSTI2020

Materials Data on KCr(CO2)4 by Materials Project

KCr(CO2)4 crystallizes in the monoclinic P2/c space group. The structure is one-dimensional and consists of one KCr(CO2)4 ribbon oriented in the (2, 0, -1) direction. K1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (2.74 Å) and two longer (2.76 Å) K–O bond lengths. Cr3+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.94 Å) and two longer (1.95 Å) Cr–O bond length. There are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.31 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.31 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and one C3+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one C3+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr3+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr3+ and one C3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MnP2H12(CO2)4 by Materials Project

MnP2H12(CO2)4 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of one MnP2H12(CO2)4 ribbon oriented in the (0, 1, 0) direction. there are two inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to five O2- atoms to form distorted MnO5 trigonal bipyramids that share corners with five PO4 tetrahedra and an edgeedge with one MnO5 trigonal bipyramid. There are a spread of Mn–O bond distances ranging from 2.10–2.27 Å. In the second Mn2+ site, Mn2+ is bonded to five O2- atoms to form MnO5 trigonal bipyramids that share corners with five PO4 tetrahedra and an edgeedge with one MnO5 trigonal bipyramid. There are a spread of Mn–O bond distances ranging from 2.07–2.29 Å. There are eight inequivalent C2- sites. In the first C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. All C–H bond lengths are 1.10 Å. The C–O bond length is 1.45 Å. In the second C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. All C–H bond lengths are 1.10 Å. The C–O bond length is 1.44 Å. In the third C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. All C–H bond lengths are 1.10 Å. The C–O bond length is 1.45 Å. In the fourth C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. The C–O bond length is 1.45 Å. In the fifth C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. All C–H bond lengths are 1.10 Å. The C–O bond length is 1.45 Å. In the sixth C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. The C–O bond length is 1.45 Å. In the seventh C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. All C–H bond lengths are 1.10 Å. The C–O bond length is 1.44 Å. In the eighth C2- site, C2- is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one PO4 tetrahedra. All C–H bond lengths are 1.10 Å. The C–O bond length is 1.45 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CH3O tetrahedra and corners with two MnO5 trigonal bipyramids. There is two shorter (1.51 Å) and two longer (1.62 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CH3O tetrahedra and corners with three MnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CH3O tetrahedra and corners with three MnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CH3O tetrahedra and corners with two MnO5 trigonal bipyramids. There is two shorter (1.50 Å) and two longer (1.62 Å) P–O bond length. There are twenty-four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the twentieth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the twenty-first H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the twenty-second H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the twenty-third H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the twenty-fourth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn2+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn2+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two Mn2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to two Mn2+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom. In the twelfth O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn2+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn2+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one C2- and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(CO2)4 by Materials Project

Np(CO2)4 is Protactinium structured and crystallizes in the tetragonal I-4 space group. The structure is zero-dimensional and consists of two Np(CO2)4 clusters. Np6+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.39 Å) and four longer (2.57 Å) Np–O bond lengths. C+2.50+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.26 Å) C–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Np6+ and one C+2.50+ atom. The O–Np bond length is 2.57 Å. The O–C bond length is 1.24 Å. In the second O2- site, O2- is bonded in a distorted L-shaped geometry to one Np6+ and one C+2.50+ atom. The O–Np bond length is 2.39 Å. The O–C bond length is 1.26 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaH2(CO2)4 by Materials Project

BaH2(CO2)4 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of two BaH2(CO2)4 sheets oriented in the (1, 0, 0) direction. Ba2+ is bonded in a 10-coordinate geometry to two equivalent H1+ and eight O2- atoms. Both Ba–H bond lengths are 3.07 Å. There are a spread of Ba–O bond distances ranging from 2.73–3.20 Å. There are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.17 Å) and one longer (1.18 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.26 Å) and one longer (1.28 Å) C–O bond length. H1+ is bonded in a distorted single-bond geometry to one Ba2+ atom. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one C3+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Ba2+ and one C3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y(CO2)4 by Materials Project

Y(CO2)4 crystallizes in the tetragonal P4/n space group. The structure is two-dimensional and consists of one Y(CO2)4 sheet oriented in the (0, 0, 1) direction. Y3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.29 Å) and four longer (2.46 Å) Y–O bond lengths. C+3.25+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.25 Å) C–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Y3+ and one C+3.25+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to one Y3+ and one C+3.25+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Advanced Compressors for CO2-Based Power Cycles and Energy

Pumped thermal energy storage (PTES) is a cost-effective method for grid-scale, long-duration electrical energy storage (LDES). PTES uses a heat pump cycle to transfer thermal energy from a low temperature reservoir (LTR) to a high temperature reservoir (HTR), later using a heat engine cycle to reverse the process. A key component of the PTES system, the heat pump compressor, represents a significant driver to the cost, performance and operating characteristics of the PTES system. For grid-scale charging (>100 MW), traditional compressor scaling charts indicate that the operating conditions needed would be best served by a multistage axial compressor. While frame gas turbine compressors at these power ratings exist and operate at higher pressure ratios than needed for the CO2 PTES system, the inlet pressure and fluid density of this application exceed experience values. A conceptual design of a large-scale CO2 axial compressor was completed, including mean-line estimates of the compressor performance at full power conditions. The results of the conceptual design were used to refine the PTES cycle design, and updated operating conditions provided for further aero design optimization. A roughly one third scale of the first three stages of the 100 MW compressor was designed, built, and tested at relevant PTES charging conditions. Results of this test program are compared against high-resolution computational fluid dynamics models.

Compressor Heat↗
DOE OSTI2025

Fracture Network Quantification for Enhanced Reservoir Characterization in CO2 Storage Sites

Presentation slides on “Fracture Network Quantification for Enhanced Reservoir Characterization in CO2 Storage Sites” for the CCUS 2025 conference held in Houston, Texas March 3-5, 2025. Accurate reservoir characterization is fundamental for the safe and efficient operation of carbon capture, utilization, and storage (CCUS) projects. This process is not only critical during initial site selection but also plays a key role in continuously updating reservoir geomodels throughout injection operations to effectively manage subsurface storage sites. Our primary objective is to develop a comprehensive understanding of fracture networks within CO2 injection reservoirs, which are critical for predicting the behavior of injected fluids, ensuring storage integrity post-injection, and mitigating risks such as leakage or induced seismicity.

artifical intelligence / machine learning (AI/ML)↗
DOE OSTI2025

Understanding of Ag Nanocatalysts for Electrocatalytic CO2 Conversion: Effects of Particle Size and Carbon Support

In this talk, we combined ultrahigh vacuum (UHV) surface science techniques, electrochemical measurements, and computational modeling to investigate Ag based electrocatalysts for CO2 reduction reaction (CO2RR). Our goal is to understand the critical characteristics governing the activity and selectivity of Ag electrocatalysts. Ag electrocatalysts were grown on highly oriented pyrolytic graphite (HOPG) in the UHV chamber, characterized with X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), and then tested in a custom-built gastight H-cell. Supported by computational modeling based on density functional theory (DFT) calculations and microkinetic modeling (MKM), our studies revealed a strong size-dependent electrocatalytic CO2-to-CO conversion of the Ag nanoparticle electrocatalysts with average particle diameter between 2 to 6 nm. Smaller diameter (< 3 nm) particles favored H2 evolution reaction (HER) due to a high population of Ag edge sites, whereas larger diameter particles favored CO2RR as the population of Ag(100) surface sites grew. We further discovered that electronic interactions between small diameter Ag particles and highly defective carbon supports could break the size-dependent CO2RR reactivity, resulting in highly selective (CO Faradaic Efficiency > 90%) and active Ag nanoparticle electrocatalysts with sizes < 2 nm diameter. This knowledge is key to understand electrocatalysts performance and to ultimately guide electrocatalyst design

Ag nanoparticles↗
DOE OSTI2025

Fracture Network Quantification during CO2 Injection

This is the presentation prepared for the ARMA 2025 (59th US Rock Mechanics/Geomechanics Symposium) Conference held in Santa Fe, New Mexico, June 8-11, 2025. Accurate mapping and quantification of these networks are essential to ensure the integrity of CO2 storage reservoirs, understand and reduce potential leakage, and maintain long-term environmental safety. This study presents a novel machine learning-driven approach, integrated with geomechanical analysis, to quantify fracture networks and assess their spatial distribution during CO2 injection. This paper combines microseismic monitoring data with principles of hydraulic diffusivity and geomechanical analysis to characterize reservoir scale fracture network. The novelty of our approach lies in its capacity to assimilate time-dependent pressure data and microseismicity into a cohesive framework, which not only identifies microseismic triggering fronts but also tracks fracture distribution during active injection. Besides, leveraging image log data and analysis our approach also provides another angle of the insights to solidate the fracture networks understanding and geomechanical impacts. Key results from our study include the detection of over 100 distinct fracture clusters across the injection site, with fracture orientations strongly correlated with the prevailing in-situ stress field.

CO2 storage and sequestration↗
DOE OSTI2025

Solid Amine CO2 Adsorbent Degradation: Insights from Experiments and Atomistic Simulations

Direct air capture (DAC) has received significant attention this decade as a viable solution to limit global warming, although large-scale deployment is currently not economically feasible. To reach the ambitious cost target set by the U.S. of $100/ton CO2 captured and stored, significant improvements must be made to sorbent lifetime and capacity. Aminosilanes grafted onto silica supports are promising candidates for deployment in DAC systems due to their relatively high oxidative stability and low regeneration temperature. Despite myriad advancements in the field, there still exists a fundamental knowledge gap relating sorbent structure to performance. In this work, we grafted various aminosilanes onto the highly porous silica SBA-15 and characterized both oxidative stability and CO2 capacity. Material properties systematically investigated included amine moiety (primary vs. secondary), silane group structure, number of linkages to the silica support, and co-addition of impregnated amines (e.g., PEI), among others. A fixed bed system was used to execute accelerated degradation studies in the presence of humidity and varying temperatures to simulate realistic operating conditions. Atomistic simulations were combined with the experimental results to gain mechanistic insight, ultimately informing the design of next-generation materials

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2008

Airborne Carbon Dioxide Laser Absorption Spectrometer for IPDA Measurements of Tropospheric CO2: Recent Results

The National Research Council's decadal survey on Earth Science and Applications from Space[1] recommended the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission for launch in 2013-2016 as a logical follow-on to the Orbiting Carbon Observatory (OCO) which is scheduled for launch in late 2008 [2]. The use of a laser absorption measurement technique provides the required ability to make day and night measurements of CO2 over all latitudes and seasons. As a demonstrator for an approach to meeting the instrument needs for the ASCENDS mission we have developed the airborne Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) which uses the Integrated Path Differential Absorption (IPDA) Spectrometer [3] technique operating in the 2 micron wavelength region.. During 2006 a short engineering checkout flight of the CO2LAS was conducted and the results presented previously [4]. Several short flight campaigns were conducted during 2007 and we report results from these campaigns.

lidar↗
NASA NTRS2013

Miniaturized Laser Heterodyne Radiometer for Measurements of CO2 in the Atmospheric Column

We have developed a low-cost, miniaturized laser heterodyne radiometer for highly sensitive measurements of carbon dioxide (CO2) in the atmospheric column. In this passive design, sunlight that has undergone absorption by CO2 in the atmosphere is collected and mixed with continuous wave laser light that is step-scanned across the absorption feature centered at 1,573.6 nm. The resulting radio frequency beat signal is collected as a function of laser wavelength, from which the total column mole fraction can be de-convolved. We are expanding this technique to include methane (CH4) and carbon monoxide (CO), and with minor modifications, this technique can be expanded to include species such as water vapor (H2O) and nitrous oxide (N2O).

CO2↗
NASA NTRS2017

Zeolite Degradation: An Investigation of CO2 Capacity Loss of 13x Sorbent

System testing of the Carbon Dioxide Removal and Compression System (CRCS) has revealed that sufficient CO2 removal capability was not achieved with the designed system. Subsystem component analysis of the zeolite bed revealed that the sorbent material suffered significant degradation and CO2 loading capacity loss. In an effort to find the root cause of this degradation, various factors were investigated to try to reproduce the observed performance loss. These factors included contamination by vacuum pump oil, o-ring vacuum grease, loading/unloading procedures, and operations. This paper details the experiments that were performed and their results.

Air Revitalization↗
NASA NTRS2017

CO2 Capacity Sorbent Analysis Using Volumetric Measurement Approach

In support of air revitalization system sorbent selection for future space missions, Ames Research Center (ARC) has performed CO2 capacity tests on various solid sorbents to complement structural strength tests conducted at Marshall Space Flight Center (MSFC). The materials of interest are: Grace Davison Grade 544 13X, Honeywell UOP APG III, LiLSX VSA-10, BASF 13X, and Grace Davison Grade 522 5A. CO2 capacity was for all sorbent materials using a Micromeritics ASAP 2020 Physisorption Volumetric Analysis machine to produce 0C, 10C, 25C, 50C, and 75C isotherms. These data are to be used for modeling data and to provide a basis for continued sorbent research. The volumetric analysis method proved to be effective in generating consistent and repeatable data for the 13X sorbents, but the method needs to be refined to tailor to different sorbents.

Air Revitalization↗
DOE OSTI2020

Supercritical CO2 Recuperators, Presented at The ASME Turbo Expo 2017, June 29, 2017, by Dr. John Kelly, President, Altex Technologies Corporation

Closed Brayton super-critical CO2 power cycles are well suited to waste heat bottoming cycles, due to their increased efficiency and compactness, relative to Rankine steam bottoming cycles. Since waste heat applications would be retrofits, the power system compactness is important. To achieve high efficiency, these power cycles require high pressure recuperative type heat exchangers, of substantial heat duty. Current Printed Circuit Heat Exchangers (PCHE), originally developed for high pressure gas and oil applications, can be used as recuperators, but costs are higher than desired. Altex is developing a purpose-built high pressure and effectiveness recuperator to provide the reliability, compactness, performance and pressure capability of current recuperators, but at a reduced cost. The High Effectiveness Low Cost (HELC) recuperative heat exchanger design yields volume and weight metrics of .0024 m3/UA and 10.2 kg/UA, which are 4% and 77.3% below recuperator target metrics, respectively. A 50 kW test article was designed and fabricated. Performance tests on water and oil showed that the HELC design model could predict heat transfer, to within 10% of the measured value. This model was then used to project HELC performance, when operating on supercritical CO2. Besides performance tests, the test article was hydrostatically tested, for integrity at up to 4,000 psi pressure. At these conditions, some distortion of channels was encountered. To mitigate distortion, the inserts were redesigned and these results were used to project the cost of 500 kW and 5,083 kW HELC units. The cost metric for the 5,083 kW unit was determined to be $1,349/UA, which is 10% lower than the recuperator desired cost metric desired target of $1,500/UA. In addition, the 5,083 kW unit HELC cost of $61.09/kW is 33.6% lower than the $92/kW estimated cost for a PCHE. Hydrostatic pressure tests, at up to 4,000psi, showed that the unit did not leak. However, channels were distorted at this pressure differential. Design updates to minimize stress concentrations and distortion were prepared and analyzed, to show that distortion could be controlled, but to date tests have not been run to prove the design. Project results show the potential of the HELC approach, but more work is required to confirm this potential, at the larger scales of interest.

14 SOLAR ENERGY↗
DOE OSTI2020

High Effectiveness, Compact, High Pressure and Low-Cost Recuperator, Presented at The Fifth International Symposium – Super-Critical CO2 Power Cycles, San Antonio, Texas, March 28-31, 2016, by Dr. John Kelly, President, Altex Technologies Corporation

Closed Brayton super-critical CO2 power cycles are well suited to waste heat bottoming cycles, due to their increased efficiency and compactness, relative to Rankine steam bottoming cycles. Since waste heat applications would be retrofits, the power system compactness is important. To achieve high efficiency, these power cycles require high pressure recuperative type heat exchangers, of substantial heat duty. Current Printed Circuit Heat Exchangers (PCHE), originally developed for high pressure gas and oil applications, can be used as recuperators, but costs are higher than desired. Altex is developing a purpose-built high pressure and effectiveness recuperator to provide the reliability, compactness, performance and pressure capability of current recuperators, but at a reduced cost. The High Effectiveness Low Cost (HELC) recuperative heat exchanger design yields volume and weight metrics of .0024 m3/UA and 10.2 kg/UA, which are 4% and 77.3% below recuperator target metrics, respectively. A 50 kW test article was designed and fabricated. Performance tests on water and oil showed that the HELC design model could predict heat transfer, to within 10% of the measured value. This model was then used to project HELC performance, when operating on supercritical CO2. Besides performance tests, the test article was hydrostatically tested, for integrity at up to 4,000 psi pressure. At these conditions, some distortion of channels was encountered. To mitigate distortion, the inserts were redesigned and these results were used to project the cost of 500 kW and 5,083 kW HELC units. The cost metric for the 5,083 kW unit was determined to be $1,349/UA, which is 10% lower than the recuperator desired cost metric desired target of $1,500/UA. In addition, the 5,083 kW unit HELC cost of $61.09/kW is 33.6% lower than the $92/kW estimated cost for a PCHE. Hydrostatic pressure tests, at up to 4,000psi, showed that the unit did not leak. However, channels were distorted at this pressure differential. Design updates to minimize stress concentrations and distortion were prepared and analyzed, to show that distortion could be controlled, but to date tests have not been run to prove the design. Project results show the potential of the HELC approach, but more work is required to confirm this potential, at the larger scales of interest.

14 SOLAR ENERGY↗
DOE OSTI2024

Evaluating Impacts of Sustainable Aviation Fuel Production with CO2-to-Fuels Technologies on High Renewable Share Power Grids

This paper investigates the impact of Sustainable Aviation Fuel production using CO2-to-Fuels technologies on a future power grid with a high share of renewable energy. We focus on understanding the implications of the 2050 SAF production goal on the U.S. power system's long-term planning, encompassing generation, transmission, and cost analysis. Via the Regional Energy Deployment System (ReEDS) model, we developed a detailed SAF electricity demand model based on a low-temperature electrolysis-syngas fermentation-ethanol pathway. Four SAF target scenarios which aims to meet 10%, 15%, 20%, and 27% of SAF demand by 2050. These scenarios are exhaustively simulated to assess their impact on the power grid. Our results reveal that increasing SAF demand will result in higher electricity requirements, as well as expanded generator and transmission capacities, leading to an overall rise in system costs. However, these impacts are manageable within the broader context of U.S. capacity expansion plans. This study provides valuable insights into incorporating the CO2-to-Fuels electricity demand model and other carbon capture technologies in power system planning, emphasizing their significance in shaping a sustainable energy future.

BIOMASS FUELS,POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Evaluating Impacts of Sustainable Aviation Fuel Production with CO2-to-Fuels Technologies on High Renewable Share Power Grid: Preprint

This paper investigates the impact of Sustainable Aviation Fuel (SAF) production using CO2-to-Fuels technologies on a future power grid with a high share of renewable energy. We focus on understanding the implications of the 2050 SAF production goal on the U.S. power system's long-term planning, encompassing generation, transmission, and cost analysis. Via the Regional Energy Deployment System (ReEDS) model, we developed a detailed SAF electricity demand model based on a low-temperature electrolysis-syngas fermentation-ethanol pathway. Four SAF target scenarios which aimto meet 10%, 15%, 20%, and 27% of SAF demand by 2050. These scenarios are exhaustively simulated to assess their impact on the power grid. Our results reveal that increasing SAF demand will result in higher electricity requirements, as well as expanded generator and transmission capacities, leading to an overall rise in system costs. However, these impacts are manageable within the broader context of U.S. capacity expansion plans. This study provides valuable insights into incorporating the CO2-to-Fuels electricity demand model and other carbon capture technologies into power system planning, emphasizing their significance in shaping a sustainable energy future.

BIOMASS FUELS,ENERGY PLANNING, POLICY, AND ECONOMY↗