Performance Optimization of a Condenser in Ocean Thermal Energy Conversion (OTEC) System Based on Constructal Theory and a Multi-Objective Genetic Algorithm

Wu, Zhixiang; Feng, Huijun; Chen, Lingen; Ge, Yanlin

doi:10.3390/e22060641

Cited by 42 publications

(13 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A complex function formed of the entropy generation rate and total pumping power was minimized for the condenser case, which reflects the trade-off between the entropy generation rate and total pumping power [58]. Other recent research performed in this same line can be found in [59][60][61][62].…”

Section: Designs For Otec System Componentsmentioning

confidence: 98%

Ocean Thermal Energy Conversion and Other Uses of Deep Sea Water: A Review

Herrera

Sierra

Ibeas

2021

JMSE

View full text Add to dashboard Cite

Research into renewable energy is an active field of research, with photovoltaic and wind being the most representative technologies. A promising renewable energy source is Ocean Thermal Energy Conversion (OTEC), based on the temperature gradient of seawater. This technology has two contradictory features, as its efficiency is relatively low while, on the other hand, its energy source is almost unlimited. OTEC research has focused on optimizing energy extraction, with different techniques having been used for this purpose. This article presents a review of the advances and applications of OTEC technology around the world. Throughout the document, the different uses of deep seawater are analyzed; further, the current systems which generate energy through the marine temperature gradient are reviewed, and the main advantages and disadvantages of each method are highlighted. The technical operations, construction variations, and the projects that have been developed around the world and those which are in the planning phase are also detailed. The two main conclusions are that this technology is still under development, but it is quite promising, especially for regions with little access to drinking water. Second, given the high implementation costs and low conversion efficiency, the development of this technology must be sponsored by governments.

show abstract

Section: Designs For Otec System Componentsmentioning

confidence: 98%

Ocean Thermal Energy Conversion and Other Uses of Deep Sea Water: A Review

Herrera

Sierra

Ibeas

2021

JMSE

View full text Add to dashboard Cite

show abstract

“…Under the condition that the DPD is kept constant, the requirement of the heat exchangers corresponding to the high-temperature reservoirs can be reduced by increasing C L /C H or C L /C H1 and reducing C H /C w f or C H1 /C w f . Figure 16 shows the optimization flowchart for calculating the Pareto frontier using the NSGA-II algorithm [39][40][41][45][46][47][48][49][50][51][52][53][54]. With π and HCDs as the design variables and W , η , P and E as the optimization objectives, the cycle's double, triple or quadruple objective optimization is conducted.…”

Section: Optimal Thermal Capacitance Rate Matching Among the Wf And Hmentioning

confidence: 99%

Power, Efficiency, Power Density and Ecological Function Optimization for an Irreversible Modified Closed Variable-Temperature Reservoir Regenerative Brayton Cycle with One Isothermal Heating Process

et al. 2020

Self Cite

View full text Add to dashboard Cite

One or more isothermal heating process was introduced to modify single and regenerative Brayton cycles by some scholars, which effectively improved the thermal efficiency and significantly reduced the emissions. To analyze and optimize the performance of this type of Brayton cycle, a regenerative modified Brayton cycle with an isothermal heating process is established in this paper based on finite time thermodynamics. The isothermal pressure drop ratio is variable. The irreversibilities of the compressor, turbine and all heat exchangers are considered in the cycle, and the heat reservoirs are variable-temperature ones. The function expressions of four performance indexes; that is, dimensionless power output, thermal efficiency, dimensionless power density and dimensionless ecological function are obtained. With the dimensionless power density as the optimization objective, the heat conductance distributions among all heat exchangers and the thermal capacitance rate matching among the working fluid and heat reservoir are optimized. Based on the NSGA-II algorithm, the cycle’s double-, triple- and quadruple-objective optimization are conducted with the total pressure ratio and the heat conductance distributions among heat exchangers as design variables. The optimal value is chosen from the Pareto frontier by applying the LINMAP, TOPSIS and Shannon entropy methods. The results show that when the pressure ratio in the compressor is less than 12.0, it is beneficial to add the regenerator to improve the cycle performance; when the pressure ratio is greater than 12.0, adding the regenerator will reduce the cycle performance. For single-objective optimization, the four performance indexes could be maximized under the optimal pressure ratios, respectively. When the pressure ratio is greater than 9.2, the cycle is simplified to a closed irreversible simple modified Brayton cycle with one isothermal heating process and coupled to variable-temperature heat reservoirs. Therefore, when the regenerator is used, the range of pressure ratio is limited, and a suitable pressure ratio should be selected. The triple objective (dimensionless power output, dimensionless power density and dimensionless ecological function) optimization’ deviation index gained by LINMAP or TOPSIS method is the smallest. The optimization results gained in this paper could offer some new pointers for the regenerative Brayton cycles’ optimal designs.

show abstract

“…Johannessen and Kjelstrup [ 24 ] studied the EGR minimization of sulfur dioxide oxidation process. The second-generation non-dominated solution sequencing genetic algorithm (NSGA-II) has been widely used in multi-objective optimization of various engineering problems [ 25 , 26 , 27 , 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Minimum Entropy Generation Rate and Maximum Yield Optimization of Sulfuric Acid Decomposition Process Using NSGA-II

Sun

Xia

Chen

et al. 2020

Entropy

Self Cite

View full text Add to dashboard Cite

Based on the theory of finite-time thermodynamics (FTT), the effects of three design parameters, that is, inlet temperature, inlet pressure, and inlet total mole flow rate, of a tubular plug-flow sulfuric acid decomposition reactor on the total entropy generation rate (EGR) and SO2 yield are analyzed firstly. One can find that when the three design parameters are taken as optimization variables, the minimum total EGR and the maximum SO2 yield of the reference reactor restrict each other, i.e., the two different performance objectives cannot achieve the corresponding extremum values at the same time. Then, the second-generation non-dominated solution sequencing genetic algorithm (NSGA-II) is further used to pursue the minimum total EGR and the maximum SO2 yield of the reference reactor by taking the three parameters as optimization design variables. After the multi-objective optimization, the reference reactor can be Pareto improved, and the total EGR can be reduced by 9% and the SO2 yield can be increased by 14% compared to those of the reference reactor. The obtained results could provide certain theoretical guidance for the optimal design of actual sulfuric acid decomposition reactors.

show abstract

Performance Optimization of a Condenser in Ocean Thermal Energy Conversion (OTEC) System Based on Constructal Theory and a Multi-Objective Genetic Algorithm

Cited by 42 publications

References 83 publications

Ocean Thermal Energy Conversion and Other Uses of Deep Sea Water: A Review

Ocean Thermal Energy Conversion and Other Uses of Deep Sea Water: A Review

Power, Efficiency, Power Density and Ecological Function Optimization for an Irreversible Modified Closed Variable-Temperature Reservoir Regenerative Brayton Cycle with One Isothermal Heating Process

Minimum Entropy Generation Rate and Maximum Yield Optimization of Sulfuric Acid Decomposition Process Using NSGA-II

Contact Info

Product

Resources

About