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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Organic Rankine power conversion subsystem development for the small community solar thermal power system

The development and preliminary test results for an air-cooled, hermetically sealed 20 kW sub E organic Rankine cycle engine/alternator unit for use with point focussing distributed receiver solar thermal power system. A 750 F toluene is the working fluid and the system features a high speed, single-stage axial flow turbine direct-coupled to a permanent magnet alternator. Good performance was achieved with the unit in preliminary tests.

Barber, R. E.↗
NASA NTRS1982

Solar-energy-system performance evaluation: Honeywell OTS 44, Ocmulgee, Georgia

The operation and technical performance of the solar operational test site (OTS 44) are described, based on data collected between April, 1981 and August, 1981. The following topics are discussed: system description, performance assessment, operating energy, energy savings, system maintenance, and conclusions. The solar energy system at OTS 44 is a hydronic heating and cooling system consisting of 5040 square feet of liquid cooled flat plate collectors; a 4000 gallon thermal storage tank; one 25 ton capacity organic Rankine cycle engine assisted water chillers; a forced draft cooling tower; and associated piping, pumps, valves, controls and heat rejection equipment. The solar system has eight basic modes of operation and several combination modes for providing space conditioning and hot water to the building. Data monitored during the 4 months of the operational test period found that the solar system collected 285 MMBtu of thermal energy of the total incident solar energy of 1040 MMBtu and provided 210 MMBtu for cooling and 10 MMBtu for heating and hot water. The net electrical energy saving due to the solar system was approximately 2600 kWh(e), and fossil energy saving was about 20 million Btu (MMBtu).

Mathur, A. K.↗
NASA NTRS1984

Overview of waste heat utilization systems

The heavy truck diesel engine rejects a significant fraction of its fuel energy in the form of waste heat. Historically, the Department of Energy has supported technology efforts for utilization of the diesel exhaust heat. Specifically, the Turbocompound and the Organic Rankine Cycle System (ORCS) have demonstrated that meaningful improvements in highway fuel economy can be realized through waste heat utilization. For heat recovery from the high temperature exhaust of future adiabatic diesel engines, the DOE/NASA are investigating a variety of alternatives based on the Rankine, Brayton, and Stirling power cycles. Initial screening results indicate that systems of this type offer a fuel savings advantage over the turbocompound system. Capital and maintenance cost projections, however, indicate that the alternative power cycles are not competitive on an economic payback basis. Plans call for continued analysis in an attempt to identify a cost effective configuration with adequate fuel savings potential.

Bailey, M. M.↗
NASA NTRS1984

Dynamic Power Systems for Power Generation

The characteristics of dynamic power systems have considerable potential value, especially for the space station. The base of technology that makes these dynamic power systems practical is reviewed. The following types of power-generating systems are examined herein: organic Rankine cycle, potassium Rankine cycle, Brayton cycle, and Stirling cycle.

English, R. E.↗
NASA NTRS1986

Hybrid deployable/erectable solar dynamic box truss system

The design of a hybrid deployable/erectable solar dynamic box truss power generation system for the initial operation capability (IOC) of the Space Shuttle is examined. An organic Rankine cycle heat engine for IOC solar power generation is studied. The design configuration is a simple parabolic concentration where the receiver is located in the focal plane with its aperture at the focal point. The relationship between concentrator size and collection efficiency is analyzed. The geometry of the deployable graphite/epoxy box truss ring and the reflective panels of the system are described. Mass properties and dynamic analyses are performed to evaluate the center of gravity location and moments of inertia characteristics of the energy conversion subsystem (ECS). The deployable/erectable truss is applicable for large IR space telescopes and center and offset fed ECSs.

Coyner, J. V., Jr.↗
NASA NTRS1987

Development of an advanced photovoltaic concentrator system for space applications

Recent studies indicate that significant increases in system performance (increased efficiency and reduced system mass) are possible for high power space based systems by incorporating technological developments with photovoltaic power systems. The Advanced Photovoltaic Concentrator Program is an effort to take advantage of recent advancements in refractive optical elements. By using a domed Fresnel lens concentrator and a prismatic cell cover, to eliminate metallization losses, dramatic reductions in the required area and mass over current space photovoltaic systems are possible. The advanced concentrator concept also has significant advantages when compared to solar dynamic Organic Rankine Cycle power systems in Low Earth Orbit applications where energy storage is required. The program is currently involved in the selection of a material for the optical element that will survive the space environment and a demonstration of the system performance of the panel design.

Piszczor, Michael F., Jr.↗
NASA NTRS1987

Development of an integrated heat pipe-thermal storage system for a solar receiver

The Organic Rankine Cycle (ORC) Solar Dynamic Power System (SDPS) is one of the candidates for Space Station prime power application. In the low Earth orbit of the Space Station approximately 34 minutes of the 94-minute orbital period is spent in eclipse with no solar energy input to the power system. For this period the SDPS will use thermal energy storage (TES) material to provide a constant power output. An integrated heat-pipe thermal storage receiver system is being developed as part of the ORC-SDPS solar receiver. This system incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain the TES canisters within the potassium vapor space with the toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the Earth orbit, solar energy is delivered to the heat pipe in the ORC-SDPS receiver cavity. The heat pipe transforms the non-uniform solar flux incident in the heat pipe surface within the receiver cavity to an essentially uniform flux at the potassium vapor condensation interface in the heat pipe. During solar insolation, part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the balance stored in the TES units is transferred by the potassium vapor to the toluene heater tube.

Keddy, E. S.↗
NASA NTRS1988

Study of toluene rotary fluid management device and shear flow condenser performance for a space-based organic Rankine power system

Management of two-phase fluid and control of the heat transfer process in microgravity is a technical challenge that must be addressed for an orbital Organic Rankine Cycle (ORC) application. A test program was performed in 1-g that satisfactorily demonstrated the two-phase management capability of the rotating fluid management device (RFMD) and shear-flow condenser. Operational tests of the RFMD and shear flow condenser in adverse gravity orientations, confirmed that the centrifugal forces in the RFMD and the shear forces in the condenser were capable of overcoming gravity forces. In a microgravity environment, these same forces would not have to compete against gravity and would therefore be dominant. The specific test program covered the required operating range of the Space Station Solar Dynamic Rankine Cycle power system. Review of the test data verified that: fluid was pumped from the RFMD in all attitudes; subcooled states in the condenser were achieved; condensate was pushed uphill against gravity; and noncondensible gases were swept through the condenser.

Havens, Vance↗
NASA NTRS1987

Toluene stability Space Station Rankine power system

A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

Havens, V. N.↗
NASA NTRS1987

A novel photovoltaic power system which uses a large area concentrator mirror

A preliminary analysis has been made of a novel photovoltaic power system concept. The system is composed of a small area, dense photovoltaic array, a large area solar concentrator, and a battery system for energy storage. The feasibility of such a system is assessed for space power applications. The orbital efficiency, specific power, mass, and area of the system are calculated under various conditions and compared with those for the organic Rankine cycle solar dynamic system proposed for Space Station. Near term and advanced large area concentrator photovoltaic systems not only compare favorably to solar dynamic systems in terms of performance but offer other benefits as well.

Arrison, Anne↗
NASA NTRS1987

Development of an advanced photovoltaic concentrator system for space applications

Recent studies indicate that significant increases in system performance (increased efficiency and reduced system mass) are possible for high power space based systems by incorporating technological developments with photovoltaic power systems. The Advanced Photovoltaic Concentrator Program is an effort to take advantage of recent advancements in refractive optical elements. By using a domed Fresnel lens concentrator and a prismatic cell cover, to eliminate metallization losses, dramatic reductions in the required area and mass over current space photovoltaic systems are possible. The advanced concentrator concept also has significant advantages when compared to solar dynamic Organic Rankine Cycle power systems in Low Earth Orbit applications where energy storage is required. The program is currently involved in the selection of a material for the optical element that will survive the space environment and a demonstration of the system performance of the panel design.

Piszczor, Michael F., Jr.↗
NASA NTRS1988

Development of an integrated heat pipe-thermal storage system for a solar receiver

An integrated heat pipe-thermal storage system was developed as part of the Organic Rankine Cycle Solar Dynamic Power System solar receiver for space station application. The solar receiver incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain thermal energy storage (TES) canisters within the vapor space with a toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the earth orbit, solar energy is delivered to the heat pipe. Part of this thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of earth orbit, the stored energy in the TES units is transferred by the potassium vapor to the toluene heater tube. A developmental heat pipe element was constructed that contains axial arteries and a distribution wick connecting the toluene heater and the TES units to the solar insolation surface of the heat pipe. Tests were conducted to demonstrate the heat pipe, TES units, and the heater tube operation. The heat pipe element was operated at design input power of 4.8 kW. Thermal cycle tests were conducted to demonstrate the successful charge and discharge of the TES units. Axial power flux levels up to 15 watts/sq cm were demonstrated and transient tests were conducted on the heat pipe element. Details of the heat pipe development and test procedures are presented.

Keddy, E.↗
NASA NTRS1988

A review of test results on parabolic dish solar thermal power modules with dish-mounted Rankine engines and for production of process steam

This paper presents results of development testing of various solar thermal parabolic dish modules and assemblies. Most of the tests were at modules and assemblies that used a dish-mounted, organic Rankine cycle turbine for production of electric power. Some tests were also run on equipment for production of process steam or for production of electricity using dish-mounted reciprocating steam engines. These tests indicate that early modules achieve efficiencies of about 18 percent in converting sunlight to electricity (excluding the inverter but including parasitics). A number of malfunctions occurred. The performance measurements, as well as the malfunctions and other operating experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

Jaffe, Leonard D.↗
DOE OSTI2023

Tabulated Database of Closed-Loop Geothermal Systems Performance for Cloud-Based Technical and Economic Modeling of Heat Production and Electricity Generation: Preprint

To better understand the heat production, electricity generation performance and economic viability of closed loop geothermal systems in hot-dry-rock, the Closed Loop Geothermal Group, a consortium of several national labs and academic institutions has tabulated time-dependent numerical solutions and levelized cost results of two popular closed loop heat exchanger designs (u-tube and co-axial). The heat exchanger designs were evaluated for two working fluids (water and super-critical CO2) while varying seven continuous independent parameters of interest (i.e., mass flow rate, vertical depth, horizontal extent, borehole diameter, formation gradient, formation conductivity, and injection temperature). The corresponding numerical solutions (approximately 1.2 million per heat exchanger design) are stored as multi-dimensional HDF5 datasets and can be queried at off-grid points using multi-dimensional linear interpolation. A Python script was developed to query this database and estimate time-dependent electricity generation using an Organic Rankine cycle (for water) or direct turbine expansion cycle (for CO2) and perform a cost assessment. This document aims to give an overview of the HDF5 database file and highlights how to read, visualize, and query quantities of interest (e.g., levelized cost of electricity, levelized cost of heat) using the accompanying python scripts. Details regarding the capital, operation, and maintenance and levelized cost calculation using the TEA (techno-economic analysis) script are provided.

co-axial↗
DOE OSTI2022

Techno-Economic Performance of Eavor Loop 2.0

This project evaluated techno-economic performance for a sample Eavor-Loop 2.0 design for electricity production and direct-use heating. The Eavor-Loop 2.0 design investigated is a 7.5-km deep closed-loop geothermal system consisting of 12 laterals for a total of more than 90 km of downhole well and lateral length. Both a high geothermal gradient scenario of 60 degrees C/km and a low geothermal gradient scenario of 30 degrees C/km were considered. With pure water injected at 60 degrees C and 80 kg/s, reservoir simulations with the Slender-Body Theory simulator indicate average production temperatures over a 30-year lifetime of ~125 degrees C and ~210 degrees C for the low and high geothermal gradient scenario, respectively. These correspond to heat production of ~22 M Wth and ~51 M Wth, respectively. Using IPSEpro simulations, we find average power production of ~2.2 M We and ~8.6 M We, respectively, for a subcritical organic Rankine cycle power plant with air-cooled condensers. Cost estimates indicate the overall capital and levelized costs are dominated by the lateral drilling cost. Obtaining a levelized cost of electricity below $70/M Wh requires a geothermal gradient of 60 degrees C/km, a discount rate below 9%, and lateral drilling cost below $400/m. A well cost model indicates that ~$400/m for the Eavor-Loop 2.0 design investigated can be obtained for a drilling rate of penetration about 40 ft/hr (with bit life of 50 hours), and omitting casing and cement. Traditional (geothermal) well drilling has achieved these drilling rate conditions, including the Utah FORGE project where the rate of penetration has exceeded 50 ft/hr in granite. However, it is unclear if these conditions are still valid for drilling the Eavor-Loop 2.0 laterals (i.e., ~82 km of laterals at 4 to 7.5-km vertical depth with rock temperatures up to 460 degrees C), as such downhole completion has never been developed before. Competitive levelized cost of heat values ($1.2-$8.2/GJ) are calculated, even for the low geothermal gradient scenario (30 degrees C/km) and lateral drilling cost of $600/m.

advanced geothermal system↗
NASA NTRS1984

Dynamic Conversion Working Group Summary

The potential of dynamic conversion devices for use in solar and nuclear dynamic space power systems was addressed. Conversion systems considered were based on the use of Brayton, Stirling and Rankine cycles. Both organic and liquid metal Rankine cycles were included. The basic system considerations were: mission requirements, system attributes, system options, technology issues and constraints, and priorities of needed technology development. Mission requirements, where dynamic conversion was considered enabling technology, were identified along with the associated power levels and potential energy sources. When considering the system options special attention was given to recommend operating temperatures and other significant discriminators. A list of prioritized tasks considered important for the successful development of dynamic conversion systems for 1995 and beyond was compiled.

Chaffee, N.↗
DOE OSTI2022

Off-design performance of an organic Rankine-vapor compression cooling cycle using R1234ze(E)

In this study, a 264 kW th organic Rankine-vapor compression cycle (ORVC) was experimentally tested over a range of conditions to quantify the individual impact of off-design external conditions. The ORVC was designed to recover waste heat at 91 °C, reject heat to a liquid condenser stream at 30 °C, and produce chilled water at 7 °C. Here, the condenser heat rejection temperature was varied from 16.6 °C to 32.6 °C, the chilled water delivery temperature was varied between 2.1 °C and 13.1 °C, and the heat input temperature was varied from 91 °C to 120 °C. As the condenser heat rejection temperature decreased, the coefficient of performance (COP) of the ORVC improved from 0.558 at 30 °C to 0.682 at 16.6 °C, despite a reduction in compressor isentropic efficiency. Although the chilled water temperature variation had almost no impact on the organic Rankine cycle performance, the compressor efficiency decreased when the delivery temperature was below 7 °C. At the highest chilled water temperature, 13.1 °C, the COP of the ORVC was 0.643. Compressor stall was noted when the condenser heat rejection temperature was greater than 32.6 °C and the chilled water delivery temperature was below 2.1 °C. Increasing the driving heat source inlet temperature improved the COP of the ORVC and the thermal efficiency of the organic Rankine power cycle, while decreasing the efficiency of the compressor and the COP of vapor compression cycle. In addition, the integrated part load value of the system was determined through experimentation to be 0.682, which provides a realistic estimate of real-world performance.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2021

Experimental validation of an organic rankine-vapor compression cooling cycle using low GWP refrigerant R1234ze(E)

There is a significant global opportunity to capture and utilize low grade waste heat to reduce fossil fuel consumption, greenhouse gas emissions, and improve energy efficiency across a wide range of industries. In this work, an advanced type of thermally activated cooling system, an organic Rankine-vapor compression cycle (ORVC) with novel heat integration strategies, was designed and tested at a relevant scale for industrial waste heat recovery (300 kW th cooling capacity). The ORVC linked an organic Rankine power cycle and a vapor compression cooling cycle using a turbine and compressor that shared a single shaft. The ORVC test facility absorbed waste heat from a liquid stream at 91 °C to simulate engine coolant in diesel generator sets, rejected heat to a glycol stream at 30 °C, and generated chilled water at 7 °C. A cooling capacity of 264 kW ± 3.5 kW was experimentally validated with a COP of 0.56 ± 0.01 during steady-state operation at the design temperatures. The thermal efficiency, accounting for pump work, of the Rankine cycle was 7.7% ± 0.22% and the COP of the vapor compression cycle was 5.25 ± 0.09. The centrifugal turbo-compressor operated at 31.5 kRPM ± 0.3 kRPM, with a turbine and compressor isentropic efficiencies of 76.7% ± 0.90% and 84.8% ± 0.54%, respectively, with near-perfect power transmission between these components. The pressure drop in the piping and heat exchangers were significantly larger than expected which had a detrimental impact on the performance of the ORVC. In addition, the condenser on the cooling cycle could not deliver the subcooling as specified from the design point modeling. Furthermore, the results from the sensitivity analysis showed that the higher condenser glycol outlet temperature had the largest impact on performance, which is consistent with other analytical models in the literature. When the ORVC simulations were updated with experimental values for isentropic efficiencies of the turbomachinery, the thermal COP was 0.66 which represents an estimate of the predicted performance if test facility limitations are overcome.

30 DIRECT ENERGY CONVERSION↗