Optimal allocation of heat exchangers in a Supercritical carbon dioxide power cycle for waste heat recovery

2019 ◽  
Vol 199 ◽  
pp. 112002 ◽  
Author(s):  
Sun-Ik Na ◽  
Min Soo Kim ◽  
Young-Jin Baik ◽  
Minsung Kim
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Optimal Allocation ◽  
Waste Heat ◽  
Power Cycle ◽  
Supercritical Carbon

Effect of Gaseous Admixtures on Cycles With Supercritical Carbon Dioxide

2016 ◽  
Author(s):  
Ladislav Vesely ◽  
Vaclav Dostal ◽  
Jan Stepanek
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Heat Exchangers ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Optimum Ratio ◽  
Pinch Point ◽  
Positive Effects ◽  
Cycle Efficiency ◽  
Supercritical Carbon

Supercritical carbon dioxide cycles are recently very perspective and they are researched all around the world. CO2 is an interesting medium for applications in many technologies, from nuclear energy through geothermal, solar and waste heat recovery systems. However, S-CO2 cycles have several issues which have to be researched, one of them being the presence of the so called pinch point in the heat exchangers design. Therefore, the Czech Technical University (CTU) conducts research on supercritical carbon dioxide cycles, which are focused on the effect of the gaseous admixtures in S-CO2 on different cycle components. The research is primarily focused on the pinch point shift within heat exchangers caused by gaseous admixtures. Previous work has shown that the pinch point can be removed with the addition of small amounts of another gases. However, it is also important to describe the effect on the performance of the cycles. This is the main topic of this paper. One of the reasons for this research is the positive effects on components are possible. The first part of the study is focused on the development of computational code for calculation of the basic S-CO2 cycles with mixtures. The second part of the study is focused on the calculation of basic cycles for binary mixtures. The calculation will be performed for pure CO2 and some binary mixture. He, CO, O2, N2, Ar will be used for the calculation as the most common admixtures, furthermore H2, CH4 and H2S will be used as well. The last part of the study will be focused on the optimization of individual cycles for different amount of admixtures in CO2. The result of this study will define the optimum ratio of admixtures and description of their effect on cycle efficiency.

scholarly journals Design optimization of supercritical carbon dioxide (s-CO2) cycles for waste heat recovery from marine engines

2021 ◽  
pp. 1-44
Author(s):  
Md. J. Hossain ◽  
Jahedul Islam Chowdhury ◽  
Nazmiye Balta-Ozkan ◽  
Faisal Asfand ◽  
Syamimi Saadon ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Recovery System ◽  
Heat Recovery System ◽  
State Models ◽  
Supercritical Carbon

Abstract The global climate change challenge and the international commitment to reduce carbon emission can be addressed by improving energy conversion efficiency and adopting efficient waste heat recovery technologies. Supercritical carbon dioxide (s-CO2) cycles that offer a compact footprint and higher cycle efficiency are investigated in this study to utilize the waste heat of the exhaust gas from a marine diesel engine (Wärtsilä-18V50DF, 17.55 MW). Steady-state models of basic, recuperated and reheated s-CO2 Brayton cycles are developed and optimised for net work and thermal efficiency in Aspen Plus to simulate and compare their performances. Results show that the reheated cycle performs marginally better than the recuperated cycle accounting for the highest optimised net-work and thermal efficiency. For the reheated and recuperated cycle, the optimized net-work ranges from 648–2860 kW and 628–2852 kW respectively, while optimized thermal efficiency ranges are 15.2–36.3% and 14.8–35.6% respectively. Besides, an energy efficiency improvement of 6.3% is achievable when the engine is integrated with an s-CO2 waste heat recovery system which is operated by flue gas with a temperature of 373 °C and mass flow rate of 28.2 kg/s, compared to the engine without a heat recovery system.

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