Optimization of Supercritical CO2 Brayton Cycle for Simple Cycle Gas Turbines Exhaust Heat Recovery Using Genetic Algorithm

For the application of waste heat recovery (WHR), supercritical CO2 (S-CO2) Brayton power cycles offer significant suitable advantages such as compactness, low capital cost and applicable to a broad range of heat source temperatures. The current study is focused on thermodynamic modelling and optimization of Recuperated (RC) and Recuperated Recompression (RRC) S-CO2 Brayton cycles for exhaust heat recovery from a next generation heavy duty simple cycle gas turbine using a genetic algorithm. The Genetic Algorithm (GA) is mainly based on bio-inspired operators such as crossover, mutation and selection. This non-gradient based algorithm yields a simultaneous optimization of key S-CO2 Brayton cycle decision variables such as turbine inlet temperature, pinch point temperature difference, compressor pressure ratio. It also outputs optimized mass flow rate of CO2 for the fixed mass flow rate and temperature of the exhaust gas. The main goal of the optimization is to maximize power out of the exhaust stream which makes it single objective optimization. The optimization is based on thermodynamic analysis with suitable practical assumptions which can be varied according to the need of user. Further the optimal cycle design points are presented for both RC and RRC configurations and comparison of net power output is established for waste heat recovery.

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Optimization of Supercritical CO2 Brayton Cycle for Simple Cycle Gas Turbines Exhaust Heat Recovery Using Genetic Algorithm

Journal of Energy Resources Technology ◽

10.1115/1.4039446 ◽

2018 ◽

Vol 140 (7) ◽

Cited By ~ 20

Author(s):

Akshay Khadse ◽

Lauren Blanchette ◽

Jayanta Kapat ◽

Subith Vasu ◽

Jahed Hossain ◽

...

Keyword(s):

Genetic Algorithm ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Supercritical Co2 ◽

Heat Recovery ◽

Brayton Cycle ◽

Exhaust Gas ◽

Exhaust Heat ◽

Exhaust Heat Recovery

For the application of waste heat recovery (WHR), supercritical CO2 (S-CO2) Brayton power cycles offer significant suitable advantages such as compactness, low capital cost, and applicability to a broad range of heat source temperatures. The current study is focused on thermodynamic modeling and optimization of recuperated (RC) and recuperated recompression (RRC) configurations of S-CO2 Brayton cycles for exhaust heat recovery from a next generation heavy duty simple cycle gas turbine using genetic algorithm (GA). This nongradient based algorithm yields a simultaneous optimization of key S-CO2 Brayton cycle decision variables such as turbine inlet temperature, pinch point temperature difference, compressor pressure ratio, and mass flow rate of CO2. The main goal of the optimization is to maximize power out of the exhaust stream which makes it single objective optimization. The optimization is based on thermodynamic analysis with suitable practical assumptions which can be varied according to the need of user. The optimal cycle design points are presented for both RC and RRC configurations and comparison of net power output is established for WHR. For the chosen exhaust gas mass flow rate, RRC cycle yields more power output than RC cycle. The main conclusion drawn from the current study is that the choice of best cycle for WHR actually depends heavily on mass flow rate of the exhaust gas. Further, the economic analysis of the more power producing RRC cycle is performed and cost comparison between the optimized RRC cycle and steam Rankine bottoming cycle is presented.

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Thermodynamic Analysis of Supercritical Carbon Dioxide Cycle for Internal Combustion Engine Waste Heat Recovery

Processes ◽

10.3390/pr8020216 ◽

2020 ◽

Vol 8 (2) ◽

pp. 216 ◽

Cited By ~ 1

Author(s):

Wan Yu ◽

Qichao Gong ◽

Dan Gao ◽

Gang Wang ◽

Huashan Su ◽

...

Keyword(s):

Carbon Dioxide ◽

Thermal Efficiency ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Combustion Engine ◽

Recovery Ratio ◽

Split Flow ◽

Exhaust Heat ◽

Exhaust Heat Recovery

Waste heat recovery of the internal combustion engine (ICE) has attracted much attention, and the supercritical carbon dioxide (S-CO2) cycle was considered as a promising technology. In this paper, a comparison of four S-CO2 cycles for waste heat recovery from the ICE was presented. Improving the exhaust heat recovery ratio and cycle thermal efficiency were significant to the net output power. A discussion about four different cycles with different design parameters was conducted, along with a thermodynamic performance. The results showed that choosing an appropriate inlet pressure of the compressor could achieve the maximum exhaust heat recovery ratio, and the pressure increased with the rising of the turbine inlet pressure and compressor inlet temperature. The maximum exhaust heat recovery ratio for recuperation and pre-compression of the S-CO2 cycle were achieved at 7.65 Mpa and 5.8 MPa, respectively. For the split-flow recompression cycle, thermal efficiency first increased with the increasing of the split ratio (SR), then decreased with a further increase of the SR, but the exhaust heat recovery ratio showed a sustained downward trend with the increase of the SR. For the split-flow expansion cycle, the optimal SR was 0.43 when the thermal efficiency and exhaust heat recovery ratio achieved the maximum. The highest recovery ratio was 24.75% for the split-flow expansion cycle when the total output power, which is the sum of the ICE power output and turbine mechanical power output, increased 15.3%. The thermal performance of the split-flow expansion cycle was the best compared to the other three cycles.

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Waste heat recovery of a combined regenerative gas turbine - recompression supercritical CO2 Brayton cycle driven by a hybrid solar-biomass heat source for multi-generation purpose: 4E analysis and parametric study

Energy ◽

10.1016/j.energy.2021.121432 ◽

2021 ◽

pp. 121432

Author(s):

Yan Cao ◽

Hamed Habibi ◽

Mohammad Zoghi ◽

Amir Raise

Keyword(s):

Heat Source ◽

Gas Turbine ◽

Parametric Study ◽

Supercritical Co2 ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Brayton Cycle

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Thermal-hydraulic performance analysis of printed circuit heat exchanger precooler in the Brayton cycle for supercritical CO2 waste heat recovery

Applied Energy ◽

10.1016/j.apenergy.2021.117923 ◽

2022 ◽

Vol 305 ◽

pp. 117923

Author(s):

Bohan Liu ◽

Mingjian Lu ◽

Bo Shui ◽

Yuwei Sun ◽

Wei Wei

Keyword(s):

Heat Exchanger ◽

Performance Analysis ◽

Supercritical Co2 ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Hydraulic Performance ◽

Brayton Cycle ◽

Printed Circuit

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Exergoeconomic analysis of a novel trigeneration system containing supercritical CO2 Brayton cycle, organic Rankine cycle and absorption refrigeration cycle for gas turbine waste heat recovery

Energy Conversion and Management ◽

10.1016/j.enconman.2020.113064 ◽

2020 ◽

Vol 221 ◽

pp. 113064 ◽

Cited By ~ 2

Author(s):

Shukun Wang ◽

Chao Liu ◽

Jie Li ◽

Zhuang Sun ◽

Xiaoxue Chen ◽

...

Keyword(s):

Supercritical Co2 ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Refrigeration Cycle ◽

Brayton Cycle ◽

Absorption Refrigeration ◽

Exergoeconomic Analysis

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Gas Turbine Engine Exhaust Waste Heat Recovery Using Supercritical CO2 Brayton Cycle With Thermoelectric Generator Technology

Volume 1: Advances in Solar Buildings and Conservation; Climate Control and the Environment; Alternate Fuels and Infrastructure; ARPA-E; Combined Energy Cycles, CHP, CCHP, and Smart Grids; Concentrating Solar Power; Economic, Environmental, and Policy Aspects of Alternate Energy; Geothermal Energy, Harvesting, Ocean Energy and Other Emerging Technologies; Hydrogen Energy Technologies; Low/Zero Emission Power Plants and Carbon Sequestration; Micro and Nano Technology Applications and Materials ◽

10.1115/es2015-49059 ◽

2015 ◽

Cited By ~ 2

Author(s):

Francis A. Di Bella

Keyword(s):

Gas Turbine ◽

Supercritical Co2 ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Brayton Cycle ◽

Prime Mover ◽

Engine Exhaust ◽

Turbine Engine ◽

Exhaust Waste Heat

This presentation will discuss the results of the feasibility analysis of a Brayton cycle-based, supercritical CO2 system that recovers waste heat from an MT30 gas turbine used in marine applications. The analysis also included the use of thermoelectric generator (TEG) devices that are one of several direct energy conversion methods known to be applicable to waste heat recovery. The analysis was conducted by Concepts NREC, in collaboration with the Maine Maritime Academy and their principal consultant, Thermoelectric Power Systems, LLC. The feasibility analysis was conducted under Navy SBIR Proposal Number N103-229-0533, entitled “Gas Turbine Engine Exhaust Waste Heat Recovery Shipboard Module Development”. The objective of the project was to improve the energy efficiency of the MT30 prime-mover power system for the Navy and other commercial vessels. The performance goal for the energy recovery system was to improve the fuel economy of the prime mover by 20% when significantly part-loaded.

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Experimental Characterization of an Adaptive Supersonic Micro Turbine for Waste Heat Recovery Applications

Energies ◽

10.3390/en15010025 ◽

2021 ◽

Vol 15 (1) ◽

pp. 25

Author(s):

Tobias Popp ◽

Andreas P. Weiß ◽

Florian Heberle ◽

Julia Winkler ◽

Rüdiger Scharf ◽

...

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Pressure Ratio ◽

Micro Turbine ◽

Swallowing Capacity

Micro turbines (<100 kWel) are commercially used as expansion machines in waste heat recovery (WHR) systems such as organic Rankine cycles (ORCs). These highly loaded turbines are generally designed for a specific parameter set, and their isentropic expansion efficiency significantly deteriorates when the mass flow rate of the WHR system deviates from the design point. However, in numerous industry processes that are potentially interesting for the implementation of a WHR process, the temperature, mass flow rate or both can fluctuate significantly, resulting in fluctuations in the WHR system as well. In such circumstances, the inlet pressure of the ORC turbine, and therefore the reversible cycle efficiency must be significantly reduced during these fluctuations. In this context, the authors developed an adaptive supersonic micro turbine for WHR applications. The variable geometry of the turbine nozzles enables an adjustment of the swallowing capacity in respect of the available mass flow rate in order to keep the upper cycle pressure constant. In this paper, an experimental test series of a WHR ORC test rig equipped with the developed adaptive supersonic micro turbine is analysed. The adaptive turbine is characterized concerning its off-design performance and the results are compared to a reference turbine with fixed geometry. To create a fair data basis for this comparison, a digital twin of the plant based on experimental data was built. In addition to the characterization of the turbine itself, the influence of the improved pressure ratio on the energy conversion chain of the entire ORC is analysed.

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