Loop Transient Performance With a Closed Loop sCO2 Brayton Cycle

2021 ◽  
Author(s):  
Stefan D. Cich ◽  
J. Jeffrey Moore ◽  
Meera Day Towler ◽  
Jason Mortzheim
Keyword(s):  
Atmospheric Pressure ◽  
Closed Loop ◽  
Operating Conditions ◽  
Department Of Energy ◽  
Brayton Cycle ◽  
Transient Performance ◽  
Start Up ◽  
The Us ◽  
Successful Testing ◽  
And Performance

Abstract Recent testing has been completed on a 1 MWe supercritical carbon dioxide (sCO2) closed loop recuperated cycle under funding from the US Department of Energy (DOE) Sunshot initiative and industry partners. Some of the goals of this funding included the development of a 1 MWe loop, a 10 MWe turbine, and performance and mechanical testing. One of the key challenges that presented itself was the filling, start-up, and shut down of the entire system. Understanding the loop transient performance is important when having to bring a turbine online, transitioning from peak to partial loading, and also managing routine and emergency shut downs. Due to large changes in density near the critical point for CO2 and its tendency to form dry ice when expanded to atmospheric pressure, managing loop filling and venting is critical in ensuring that components are not damaged. With successful testing up to 715°C and 234 bar, this paper will provide updated data to, “Loop Filling and Start Up with a Closed Loop sCO2 Brayton Cycle [1].” While the previous paper focused on early trips and start up challenges, this paper will focus on the specific challenges at maximum operating conditions, and how the loop was managed when getting up to these high temperatures and pressures and how the loop behaved during a high temperature trip when compared to a controlled shut down from maximum operating conditions.

Loop Filling and Start Up With a Closed Loop sCO2 Brayton Cycle

2019 ◽  
Author(s):  
Stefan D. Cich ◽  
J. Jeffrey Moore ◽  
Meera Day Towler ◽  
Jason Mortzheim ◽  
Douglas Hofer
Keyword(s):  
Atmospheric Pressure ◽  
Closed Loop ◽  
Brayton Cycle ◽  
Entire System ◽  
Thermal Transients ◽  
Start Up ◽  
The Us ◽  
Proper Mass ◽  
Gas Seals ◽  
And Performance

Abstract Recent testing has been performed on a 1 MWe sCO2 closed loop recuperated cycle under funding from the US DOE Sunshot initiative and industry partners. Some of the goals of this funding included the development of a 1 MWe loop, a 10 MWe turbine, and performance and mechanical testing. One of the key challenges that presented itself was the filling, start-up, and shut down of the entire system. Understanding the loop transient performance is important when having to bring a turbine online, transitioning from peak to partial loading, and also managing routine and emergency shut downs. Due to large changes in density near the critical point for CO2 and its tendency to form dry ice when expanded to atmospheric pressure, managing loop filling and venting is critical in ensuring that components do not get damaged. Specific challenges were centered on protecting the dry gas seals, maintaining proper mass in the loop, and also thermal transients during trips. This paper will take a detailed look at the challenges encountered during start up and shut downs, and also the solutions that were implemented to successful transition between different phases of the testing.

Testing of the US Solar Pilot Plant Receiver

1986 ◽  
Vol 108 (2) ◽  
pp. 146-149 ◽  
Author(s):  
J. M. Friefeld ◽  
G. C. Coleman
Keyword(s):  
Pilot Plant ◽  
Operating Conditions ◽  
Department Of Energy ◽  
Operating Characteristics ◽  
Water Steam ◽  
Emergency Situations ◽  
The Us ◽  
And Performance ◽  
Solar Receiver ◽  
Limited Testing

The US Department of Energy (DOE) is actively engaged in the design and construction of America’s first Solar Thermal Electric Pilot Plant at Barstow, California. Preconstruction tests of the external, single-pass-to-superheat, water/steam receiver under actual solar operating conditions were conducted to validate the design at the earliest possible date to assure the achievement of Pilot Plant operating goals. Receiver steady-state and transient operating characteristics and performance were investigated during clear day, intermittent cloud, and simulated emergency situations. Testing concluded with limited testing of the receiver at flux and power levels above the maximum expected Pilot Plant conditions. The test program successfully achieved the overall objective of confirming the design of the Pilot Plant solar receiver.

Entrepreneurs' Technical Assistance Program (ETAP)

1999 ◽  
Vol 13 (1) ◽  
pp. 61-64 ◽  
Author(s):  
F.J. Fraikor ◽  
S.K. Purcell ◽  
R.J. Taylor
Keyword(s):  
Local Governments ◽  
Technical Assistance ◽  
Department Of Energy ◽  
Federal State ◽  
Assistance Program ◽  
Rocky Flats ◽  
Start Up ◽  
The Us ◽  
Technical Assistance Program ◽  
State And Local

In June 1993, the US Department of Energy announced the decision to shut down production of nuclear weapon components at its Rocky Flats plant located near Denver, Colorado, and begin a long-term clean-up of the facility. Faced with very severe economic impacts from downsizing the facility (approximately 8,000 employees at its peak), federal, state, and local governments formed a Community Reuse Organization to develop and implement strategies to mitigate the effects of displaced workers and lost income. This paper describes an innovative partnership concept, specifically aimed at providing technology-based start-up companies with world-class university expertise that they otherwise could not afford.

Pressurizer Safety Valve Data Collection, Analysis, and Performance

2016 ◽  
Author(s):  
T. Esselman ◽  
G. Zysk ◽  
P. Streeter ◽  
B. Elaidi ◽  
H. Garcia ◽  
...  
Keyword(s):  
Safety Valve ◽  
Critical Path ◽  
Operating Conditions ◽  
Inlet Pipe ◽  
Data Analyses ◽  
Thermal Growth ◽  
Start Up ◽  
Pressurization Rate ◽  
And Performance ◽  
Water Seal

The Pressurizer Safety Valves (PSVs) at Diablo Canyon Power Plant were manufactured by Crosby and are model 6M6 HB-86-BP valves. The valves have intermittingly experienced leakage as the units are heated up and pressurized to normal operating conditions. When leakage occurs, a time-consuming de-pressurization and re-pressurization process is implemented that causes significant delays in the return to power after an outage. Following the elimination of the upstream water seal, leakage has occurred on individual valves during all but one start-up. After recent PSV leakage, instrumentation was installed to obtain information during the subsequent unit heat up and pressurization. The instruments included thermocouples on the inlet pipe, the discharge pipe, and the valve. Data was collected during a unit start-up in which two of the three installed valves leaked. Piping and valve analyses were performed using the data to modify the valve installation procedures, to modify the process for accommodating piping thermal growth, and to modify the pressurization rate during start-up. Upon implementation of these changes, none of the PSVs leaked during the subsequent unit heat up and pressurization, saving more than 24 critical path hours. The data, analyses, and modifications will be described along with the analyses used to support an increase in the pressurization rate for unit start-up.

Multiphysics coupling in the Exascale computing project

2021 ◽  
pp. 109434202110289
Author(s):  
Thomas M Evans ◽  
Julia C White
Keyword(s):  
High Performance ◽  
Computational Science ◽  
Department Of Energy ◽  
Special Issue ◽  
Computational Accuracy ◽  
Exascale Computing ◽  
The Us ◽  
Multiphysics Coupling ◽  
And Performance ◽  
Performance Computing

Multiphysics coupling presents a significant challenge in terms of both computational accuracy and performance. Achieving high performance on coupled simulations can be particularly challenging in a high-performance computing context. The US Department of Energy Exascale Computing Project has the mission to prepare mission-relevant applications for the delivery of the exascale computers starting in 2023. Many of these applications require multiphysics coupling, and the implementations must be performant on exascale hardware. In this special issue we feature six articles performing advanced multiphysics coupling that span the computational science domains in the Exascale Computing Project.

Selecting the Optimum Supercritical CO2 Cycle for Indirect-Fired Applications

2019 ◽  
Author(s):  
Brittany Tom ◽  
January Smith ◽  
Aaron M. McClung
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Co2 ◽  
Operating Conditions ◽  
Working Fluid ◽  
Performance Goals ◽  
Brayton Cycle ◽  
Power Cycle ◽  
And Performance ◽  
Supercritical Carbon

Abstract Existing research has demonstrated the viability of supercritical carbon dioxide as an efficient working fluid with numerous advantages over steam in power cycle applications. Selecting the appropriate power cycle configuration for a given application depends on expected operating conditions and performance goals. This paper presents a comparison for three indirect fired sCO2 cycles: recompression closed Brayton cycle, dual loop cascaded cycle, and partial condensation cycle. Each cycle was modeled in NPSS with an air side heater, given the same baseline assumptions and optimized over a range of conditions. Additionally, limitations on the heater system are discussed.

Performance of Supercritical CO2 Dry Gas Seals Near the Critical Point

2016 ◽  
Author(s):  
Mohd Fairuz Zakariya ◽  
Ingo H. J. Jahn
Keyword(s):  
Critical Point ◽  
Supercritical Co2 ◽  
Closed Loop ◽  
High Pressures ◽  
Thermal Power ◽  
Operating Conditions ◽  
Real Gas ◽  
Dry Gas Seal ◽  
Gas Seals ◽  
And Performance

The Queensland Geothermal Energy Centre of Excellence is investigating the use of supercritical CO2 closed loop Brayton cycles in the Concentrated Solar Thermal power cycle plant. One of the important components in the turbomachinery within the plant are seals. As the cycle is closed loop and operating at high pressures, dry gas seals have been recommended for future use in these systems. One of the main challenges of using supercritical CO2 dry gas seals is that operating conditions are near the critical point. In the supercritical region in the vicinity of the critical point (304 K, 7.4 MPa), CO2 behaves as a real-gas, exhibiting large and abrupt non-linear changes in fluid and transport properties and high densities. To correctly predict the seal operation and performance, the interaction between this real gas and the seal rotor (primary ring) and the seal stator (mating ring) need to analysed and investigated in detail, as they can lead to significant changes in flow and seal performance. Results from this paper show that increased centrifugal effects caused by higher gas densities can reduce the pressure in the sealing dam region. This adversely affects the loading capacity of the dry gas seal. However, it also benefits seal performances by reducing the leakage rate. The current work presents an investigation of the supercritical CO2 dry gas seals operating close to the critical point with an inlet pressure and temperature of 8.5Mpa and 370K respectively and a speed of 30000 RPM. Results highlighting the effects of the groove length or dam to groove ratio on the performance of the dry gas seal are presented. The seal is simulated using Computational Fluid Dynamics to study the flow behaviour of the supercitical CO2 in the dry gas seal. Supercritical CO2 fluid properties are based on the fluid database REFPROP. The numerical model was validated with previous work and good agreement was demonstrated.

Technoeconomic Analysis of Alternative Solarized s-CO2 Brayton Cycle Configurations

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Clifford K. Ho ◽  
Matthew Carlson ◽  
Pardeep Garg ◽  
Pramod Kumar
Keyword(s):  
Solar Collector ◽  
Closed Loop ◽  
Variable Temperature ◽  
Brayton Cycle ◽  
Power Cycle ◽  
Technoeconomic Analysis ◽  
Heating Source ◽  
Power Block ◽  
And Performance ◽  
Lower Temperature

This paper evaluates cost and performance tradeoffs of alternative supercritical carbon dioxide (s-CO2) closed-loop Brayton cycle configurations with a concentrated solar heat source. Alternative s-CO2 power cycle configurations include simple, recompression, cascaded, and partial cooling cycles. Results show that the simple closed-loop Brayton cycle yielded the lowest power-block component costs while allowing variable temperature differentials across the s-CO2 heating source, depending on the level of recuperation. Lower temperature differentials led to higher sensible storage costs, but cycle configurations with lower temperature differentials (higher recuperation) yielded higher cycle efficiencies and lower solar collector and receiver costs. The cycles with higher efficiencies (simple recuperated, recompression, and partial cooling) yielded the lowest overall solar and power-block component costs for a prescribed power output.

scholarly journals Cost and Performance Tradeoffs of Alternative Solar-Driven S-CO2 Brayton Cycle Configurations

2015 ◽  
Author(s):  
Clifford K. Ho ◽  
Matthew Carlson ◽  
Pardeep Garg ◽  
Pramod Kumar
Keyword(s):  
Carbon Dioxide ◽  
Solar Collector ◽  
Closed Loop ◽  
Variable Temperature ◽  
Brayton Cycle ◽  
Power Cycle ◽  
Heating Source ◽  
Power Block ◽  
And Performance ◽  
Lower Temperature

This paper evaluates cost and performance tradeoffs of alternative supercritical carbon dioxide (s-CO2) closed-loop Brayton cycle configurations with a concentrated solar heat source. Alternative s-CO2 power cycle configurations include simple, recompression, cascaded, and partial cooling cycles. Results show that the simple closed-loop Brayton cycle yielded the lowest power-block component costs while allowing variable temperature differentials across the s-CO2 heating source, depending on the level of recuperation. Lower temperature differentials led to higher sensible storage costs, but cycle configurations with lower temperature differentials (higher recuperation) yielded higher cycle efficiencies and lower solar collector and receiver costs. The cycles with higher efficiencies (simple recuperated, recompression, and partial cooling) yielded the lowest overall solar and power-block component costs for a prescribed power output.

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