Comparative thermo-economic analysis of co-axial closed-loop geothermal systems using CO2 and water as working fluids

Yu, Ying; Cheng, Fei; Cheng, Jianmei; Yang, Guodong; Ma, Xin

doi:10.1016/j.applthermaleng.2023.120710

Cited by 10 publications

(4 citation statements)

References 35 publications

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“…The blue line and red line represent the CO2 and water results reported by Yu et al, respectively. The discrepancy between the CO2 simulation results obtained from the IP-EPC model and those reported by Yu et al [18] is 1.78%; whereas for water, it is 1.97%. Consequently, considering the acceptable difference in heat power between the reference and simulation results, we can conclude that the IPEPC model demonstrates accuracy.…”

Section: Items Parameterscontrasting

confidence: 61%

“…Under the same numerical conditions as the study conducted by Yu et al [18], Figure 5 illustrates the heat power of CO2 and water with respect to different geothermal gradients. The blue line and red line represent the CO2 and water results reported by Yu et al, respectively.…”

Section: Items Parametersmentioning

confidence: 97%

“…Yu et al ( 2023) [18] Co-axial case in abandoned wells The ammonia has a relatively low inlet pressure (5 MPa) and pressure loss (2.7 MPa), which means ammonia has a lower circulation pump.…”

Section: Pokhrel Et Almentioning

confidence: 99%

“…The results of this study were compared with those of Yu et al [18] in order to validate the accuracy of the model. In the comparative study, water and CO 2 were chosen as working fluids, and the geothermal gradient of 25-45 • C/km was taken into account.…”

Section: Model Verificationmentioning

confidence: 99%

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Thermodynamic Analysis of an Increasing-Pressure Endothermic Power Cycle Integrated with Closed-Loop Geothermal Energy Extraction

Yu,

Lu,

Zhang

et al. 2024

Energies

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The thermodynamic analysis of an increasing-pressure endothermic power cycle (IPEPC) integrated with closed-loop geothermal energy extraction (CLGEE) in a geothermal well at a depth from 2 km to 5 km has been carried out in this study. Using CLGEE can avoid some typical problems associated with traditional EGS technology, such as water contamination and seismic-induced risk. Simultaneous optimization has been conducted for the structural parameters of the downhole heat exchanger (DHE), the CO2 mixture working fluid type, and the IPEPC operating parameters. The CO2-R32 mixture has been selected as the optimal working fluid for the IPEPC based on the highest net power output obtained. It has been found that, when the DHE length is 4 km, the thermosiphon effect is capable of compensating for 53.8% of the pump power consumption. As long as the DHE inlet pressure is higher than the critical pressure, a lower DHE inlet pressure results in more power production. The power generation performance of the IPEPC has been compared with that of the organic Rankine cycle (ORC), trans-critical carbon dioxide cycle (t-CO2), and single-flash (SF) systems. The comparison shows that the IPEPC has more net power output than other systems in the case that the DHE length is less than 3 km, along with a DHE outer diameter of 0.155 m. When the DHE outer diameter is increased to 0.22 m, the IPEPC has the highest net power output for the DHE length ranging from 2 km to 5 km. The application scopes obtained in this study for different power generation systems are of engineering-guiding significance for geothermal industries.

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Section: Items Parameterscontrasting

confidence: 61%

Section: Items Parametersmentioning

confidence: 97%

Section: Pokhrel Et Almentioning

confidence: 99%

Section: Model Verificationmentioning

confidence: 99%

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