Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power Cycle
Ocean thermal energy is a huge renewable and clean energy. For different applications of the Ocean Thermal Energy Conversion (OTEC) system, new objective functions are proposed and optimal CO<sub>2</sub>-based binary zeotropic mixtures for each objective function are discussed. Propane,...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-01-01
|
| Series: | Journal of Marine Science and Engineering |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-1312/11/1/140 |
| _version_ | 1797440342900867072 |
|---|---|
| author | Weixiu Shi Yin Sun Lisheng Pan Linjian Song Xiaolin Wei |
| author_facet | Weixiu Shi Yin Sun Lisheng Pan Linjian Song Xiaolin Wei |
| author_sort | Weixiu Shi |
| collection | DOAJ |
| description | Ocean thermal energy is a huge renewable and clean energy. For different applications of the Ocean Thermal Energy Conversion (OTEC) system, new objective functions are proposed and optimal CO<sub>2</sub>-based binary zeotropic mixtures for each objective function are discussed. Propane, butane, isobutane, and pentane were selected as the secondary component of the mixture working fluid. Based on each objective function, some parameters of the CO<sub>2</sub>-based binary zeotropic mixture power cycle were studied and the optimal working fluids were obtained. The results indicated that the thermal efficiency showed an upwards trend as the evaporating temperature increased from 20 to 23 °C and decreased as the molar fraction of the secondary component of the working fluid increased from 0.01 to 0.05, but the specific volumetric flow showed the opposite trend. The specific net power increased as the evaporating temperature increased, and the net power output had a greater effect on the variations in the specific net power than the molar fraction of the secondary component. When taking thermal efficiency or specific volumetric flow as the objective functions, CO<sub>2</sub>/propane was the suitable working fluid under the considered conditions; in the case that specific net power was taken as the objective function, CO<sub>2</sub>/butane (0.97/0.03 or 0.96/0.04 molar ratio) or CO<sub>2</sub>/isobutane (0.97/0.03, 0.96/0.04, or 0.95/0.05 molar ratio) were suitable under the considered evaporating temperature. |
| first_indexed | 2024-03-09T12:06:48Z |
| format | Article |
| id | doaj.art-8b019c6139d64efdb07994318f8a1b1a |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-09T12:06:48Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-8b019c6139d64efdb07994318f8a1b1a2023-11-30T22:57:44ZengMDPI AGJournal of Marine Science and Engineering2077-13122023-01-0111114010.3390/jmse11010140Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power CycleWeixiu Shi0Yin Sun1Lisheng Pan2Linjian Song3Xiaolin Wei4Beijing Engineering Research Center of Sustainable Energy and Buildings, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaBeijing Engineering Research Center of Sustainable Energy and Buildings, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaState Key Laboratory of High-Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaBeijing Engineering Research Center of Sustainable Energy and Buildings, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaState Key Laboratory of High-Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaOcean thermal energy is a huge renewable and clean energy. For different applications of the Ocean Thermal Energy Conversion (OTEC) system, new objective functions are proposed and optimal CO<sub>2</sub>-based binary zeotropic mixtures for each objective function are discussed. Propane, butane, isobutane, and pentane were selected as the secondary component of the mixture working fluid. Based on each objective function, some parameters of the CO<sub>2</sub>-based binary zeotropic mixture power cycle were studied and the optimal working fluids were obtained. The results indicated that the thermal efficiency showed an upwards trend as the evaporating temperature increased from 20 to 23 °C and decreased as the molar fraction of the secondary component of the working fluid increased from 0.01 to 0.05, but the specific volumetric flow showed the opposite trend. The specific net power increased as the evaporating temperature increased, and the net power output had a greater effect on the variations in the specific net power than the molar fraction of the secondary component. When taking thermal efficiency or specific volumetric flow as the objective functions, CO<sub>2</sub>/propane was the suitable working fluid under the considered conditions; in the case that specific net power was taken as the objective function, CO<sub>2</sub>/butane (0.97/0.03 or 0.96/0.04 molar ratio) or CO<sub>2</sub>/isobutane (0.97/0.03, 0.96/0.04, or 0.95/0.05 molar ratio) were suitable under the considered evaporating temperature.https://www.mdpi.com/2077-1312/11/1/140Ocean Thermal Energy Conversion (OTEC)CO<sub>2</sub>-based mixtureobjective functionworking fluid optimizationapplication occasionevaporating temperature |
| spellingShingle | Weixiu Shi Yin Sun Lisheng Pan Linjian Song Xiaolin Wei Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power Cycle Journal of Marine Science and Engineering Ocean Thermal Energy Conversion (OTEC) CO<sub>2</sub>-based mixture objective function working fluid optimization application occasion evaporating temperature |
| title | Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power Cycle |
| title_full | Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power Cycle |
| title_fullStr | Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power Cycle |
| title_full_unstemmed | Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power Cycle |
| title_short | Objective Functions and Performance Optimization of Ocean Thermal Energy Conversion (OTEC) with CO<sub>2</sub>-Based Binary Zeotropic Mixture Power Cycle |
| title_sort | objective functions and performance optimization of ocean thermal energy conversion otec with co sub 2 sub based binary zeotropic mixture power cycle |
| topic | Ocean Thermal Energy Conversion (OTEC) CO<sub>2</sub>-based mixture objective function working fluid optimization application occasion evaporating temperature |
| url | https://www.mdpi.com/2077-1312/11/1/140 |
| work_keys_str_mv | AT weixiushi objectivefunctionsandperformanceoptimizationofoceanthermalenergyconversionotecwithcosub2subbasedbinaryzeotropicmixturepowercycle AT yinsun objectivefunctionsandperformanceoptimizationofoceanthermalenergyconversionotecwithcosub2subbasedbinaryzeotropicmixturepowercycle AT lishengpan objectivefunctionsandperformanceoptimizationofoceanthermalenergyconversionotecwithcosub2subbasedbinaryzeotropicmixturepowercycle AT linjiansong objectivefunctionsandperformanceoptimizationofoceanthermalenergyconversionotecwithcosub2subbasedbinaryzeotropicmixturepowercycle AT xiaolinwei objectivefunctionsandperformanceoptimizationofoceanthermalenergyconversionotecwithcosub2subbasedbinaryzeotropicmixturepowercycle |