Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): Sensitivity Analysis on the Newberry Volcanic Setting
Alternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as: the working fluid mass flow rate, the casing and cement thermal properties and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5MW, after an annulus radii increase and an imposed mass flow rate of 5kg/. At 3kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provide a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.
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Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.
Posted 18 Jan, 2021
On 15 Feb, 2021
On 13 Jan, 2021
On 08 Jan, 2021
On 08 Jan, 2021
On 08 Jan, 2021
Received 10 Dec, 2020
On 10 Dec, 2020
On 28 Nov, 2020
Received 26 Nov, 2020
Invitations sent on 24 Nov, 2020
On 24 Nov, 2020
On 27 Oct, 2020
On 26 Oct, 2020
On 26 Oct, 2020
On 15 Sep, 2020
Received 10 Sep, 2020
On 22 Aug, 2020
Received 27 Jul, 2020
On 13 Jul, 2020
Received 29 Jun, 2020
On 22 Jun, 2020
Invitations sent on 10 Jun, 2020
On 08 Jun, 2020
On 07 Jun, 2020
On 07 Jun, 2020
On 07 Jun, 2020
Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): Sensitivity Analysis on the Newberry Volcanic Setting
Posted 18 Jan, 2021
On 15 Feb, 2021
On 13 Jan, 2021
On 08 Jan, 2021
On 08 Jan, 2021
On 08 Jan, 2021
Received 10 Dec, 2020
On 10 Dec, 2020
On 28 Nov, 2020
Received 26 Nov, 2020
Invitations sent on 24 Nov, 2020
On 24 Nov, 2020
On 27 Oct, 2020
On 26 Oct, 2020
On 26 Oct, 2020
On 15 Sep, 2020
Received 10 Sep, 2020
On 22 Aug, 2020
Received 27 Jul, 2020
On 13 Jul, 2020
Received 29 Jun, 2020
On 22 Jun, 2020
Invitations sent on 10 Jun, 2020
On 08 Jun, 2020
On 07 Jun, 2020
On 07 Jun, 2020
On 07 Jun, 2020
Alternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as: the working fluid mass flow rate, the casing and cement thermal properties and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5MW, after an annulus radii increase and an imposed mass flow rate of 5kg/. At 3kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provide a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.