TY - JOUR
T1 - Open-loop CO2-driven geothermal system for power generation and in-situ brackish water desalination
AU - Li, Chuanjie
AU - Kong, Hui
AU - Xiong, Jianyin
AU - Jiang, Dalin
AU - Wang, Hongsheng
AU - Zheng, Hongfei
N1 - Publisher Copyright:
© 2025 Elsevier Ltd
PY - 2025/4/1
Y1 - 2025/4/1
N2 - Utilizing CO2-driven extraction of geothermal energy enables both geological sequestration of CO2 and its resource utilization. However, previous studies on this method have neglected the management of the substantial amounts of brackish water carried by the CO2 produced from geothermal wells. To address this issue, this study proposes a new open-loop system for power generation and in-situ desalination of brackish water. Additionally, utilizing solar energy as an auxiliary heat source for secondary heating of sCO2 enables high-grade power generation. The plume geothermal unit and brackish water desalination unit are modeled, and energy and exergy analyses are conducted for the power generation unit. The capital cost and CO2 emissions of the overall system are also evaluated. The results show that the system achieves a thermal efficiency of 18.72 % and an exergy efficiency of 21.73 % for a 4.4 MW power generation unit. Compared with the cycle system using only solar energy as the heat source, the exergy efficiency of the hybrid system is increased by 4.37 %. The coupling system can yield 3.69 t/h of fresh water and achieve CO2 sequestration at a rate of 50.4 t/h. Based on multio-bjective optimization, it is concluded that the most thermoeconomic system achieves a thermal efficiency of 20.01 % with a total capital cost of $4.85 × 107. The results of related studies provide important references for the design of multienergy complementary hydroelectric cogeneration systems.
AB - Utilizing CO2-driven extraction of geothermal energy enables both geological sequestration of CO2 and its resource utilization. However, previous studies on this method have neglected the management of the substantial amounts of brackish water carried by the CO2 produced from geothermal wells. To address this issue, this study proposes a new open-loop system for power generation and in-situ desalination of brackish water. Additionally, utilizing solar energy as an auxiliary heat source for secondary heating of sCO2 enables high-grade power generation. The plume geothermal unit and brackish water desalination unit are modeled, and energy and exergy analyses are conducted for the power generation unit. The capital cost and CO2 emissions of the overall system are also evaluated. The results show that the system achieves a thermal efficiency of 18.72 % and an exergy efficiency of 21.73 % for a 4.4 MW power generation unit. Compared with the cycle system using only solar energy as the heat source, the exergy efficiency of the hybrid system is increased by 4.37 %. The coupling system can yield 3.69 t/h of fresh water and achieve CO2 sequestration at a rate of 50.4 t/h. Based on multio-bjective optimization, it is concluded that the most thermoeconomic system achieves a thermal efficiency of 20.01 % with a total capital cost of $4.85 × 107. The results of related studies provide important references for the design of multienergy complementary hydroelectric cogeneration systems.
KW - Brackish water desalination
KW - CO geological sequestration
KW - Renewable energy
KW - SCO Brayton cycle
KW - Thermodynamic efficiency
UR - http://www.scopus.com/inward/record.url?scp=85214845450&partnerID=8YFLogxK
U2 - 10.1016/j.applthermaleng.2025.125415
DO - 10.1016/j.applthermaleng.2025.125415
M3 - Article
AN - SCOPUS:85214845450
SN - 1359-4311
VL - 264
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
M1 - 125415
ER -