Geothermal heat utilization system and geothermal heat utilization method

Patent metadata

Field	Value
Publication number	US-11629889-B2
Application number	US-201816498327-A
Country	US
Kind code	B2
Filing date	Mar 28, 2018
Priority date	Mar 31, 2017
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

A geothermal heat utilization system (10) includes a pumping well (20), a water injection well (30), a pipe (13) having two ends which are immersed in water stored in the pumping well (20) and the water injection well (30) so as to connect the pumping well (20) and the water injection well (30) to each other, a pump (21) and a pump (31) which are respectively provided inside the pumping well (20) and the water injection well (30) and pump up stored water through the pipe (13), a valve (25) and a valve (35) which are respectively provided on a pressurization side of the pump (21) inside the pumping well (20) and a pressurization side of the pump (31) inside the water injection well (30), and a heat exchanger (14) which is configured to exchange heat with the pipe (13).

First claim

What is claimed is:

1. A geothermal heat utilization system comprising:
a pair of wells;
a pipe having two ends which are immersed in stored water of both of the wells so as to connect the pair of wells to each other;
a pair of pumps which are provided in the respective wells and pump up the stored water through the pipe;
valves each of which is provided on a pressurization side of one of the pumps in one of the pair of wells; and
a heat exchanger which is configured to exchange heat with the pipe, wherein
at least one of the valves includes a water injection valve configured such that water in the pipe is injected into the well, the water injection valve being immersed in stored water of the well,
the geothermal heat utilization system further comprises a lid in an opening in an upper portion of at least one well out of the wells, and
the lid limits contact of the stored water with air to limit the generation of particles due to oxidation of the stored water.

2. The geothermal heat utilization system according to claim 1 , wherein at least one of the valves includes a check valve capable of being pressurized from the pump to the pipe, the check valve being immersed in stored water of the well.

3. The geothermal heat utilization system according to claim 2 , wherein
the water injection valve is opened at a set pressure, and
the set pressure is higher than an operating pressure of the check valve, the operating pressure which is applied from the pump to the pipe.

4. The geothermal heat utilization system according to claim 3 , further comprising:
an accumulator pressure tank in the pipe.

5. A geothermal heat utilization method using the geothermal heat utilization system according to claim 3 , the geothermal heat utilization method comprising:
an in-pipe pressurization step of pumping up the stored water into the pipe using the pump provided in one of the pair of wells to pressurize an inside of the pipe; and
a heat exchange step of further pumping up the stored water into the pipe using the pump provided in one of the pair of wells after the in-pipe pressurization step to inject the stored water into the other well and perform heat exchange between the pipe and the heat exchanger.

6. The geothermal heat utilization system according to claim 2 , wherein
the geothermal heat utilization system further comprises a pressure gauge which is configured to determine a pressure in the pipe and a water injection valve control unit which is configured to control the water injection valve in relation to the determined pressure, and
the water injection valve control unit is configured to perform control of opening the water injection valve provided inside one well with respect to the other well operating the pump out of the pair of wells when the determined pressure reaches a predetermined pressure.

7. The geothermal heat utilization system according to claim 2 , further comprising:
an accumulator pressure tank in the pipe.

8. A geothermal heat utilization method using the geothermal heat utilization system according to claim 2 , the geothermal heat utilization method comprising:
an in-pipe pressurization step of pumping up the stored water into the pipe using the pump provided in one of the pair of wells to pressurize an inside of the pipe; and
a heat exchange step of further pumping up the stored water into the pipe using the pump provided in one of the pair of wells after the in-pipe pressurization step to inject the stored water into the other well and perform heat exchange between the pipe and the heat exchanger.

9. The geothermal heat utilization system according to claim 1 , wherein
the geothermal heat utilization system further comprises a pressure gauge which is configured to determine a pressure in the pipe and a water injection valve control unit which is configured to control the water injection valve in relation to the determined pressure, and
the water injection valve control unit is configured to perform control of opening the water injection valve provided inside one well with respect to the other well operating the pump out of the pair of wells when the determined pressure reaches a predetermined pressure.

10. The geothermal heat utilization system according to claim 9 , further comprising:
an accumulator pressure tank in the pipe.

11. A geothermal heat utilization method using the geothermal heat utilization system according to claim 9 , the geothermal heat utilization method comprising:
an in-pipe pressurization step of pumping up the stored water into the pipe using the pump provided in one of the pair of wells to pressurize an inside of the pipe; and
a heat exchange step of further pumping up the stored water into the pipe using the pump provided in one of the pair of wells after the in-pipe pressurization step to inject the stored water into the other well and perform heat exchange between the pipe and the heat exchanger.

12. The geothermal heat utilization system according to claim 1 , further comprising:
an accumulator pressure tank in the pipe.

13. A geothermal heat utilization method using the geothermal heat utilization system according to claim 12 , the geothermal heat utilization method comprising:
an in-pipe pressurization step of pumping up the stored water into the pipe using the pump provided in one of the pair of wells to pressurize an inside of the pipe; and
a heat exchange step of further pumping up the stored water into the pipe using the pump provided in one of the pair of wells after the in-pipe pressurization step to inject the stored water into the other well and perform heat exchange between the pipe and the heat exchanger.

14. A geothermal heat utilization method using the geothermal heat utilization system according to claim 1 , the geothermal heat utilization method comprising:
an in-pipe pressurization step of pumping up the stored water into the pipe using the pump provided in one of the pair of wells to pressurize an inside of the pipe; and
a heat exchange step of further pumping up the stored water into the pipe using the pump provided in one of the pair of wells after the in-pipe pressurization step to inject the stored water into the other well and perform heat exchange between the pipe and the heat exchanger.

Assignees

• Mitsubishi Heavy Ind Thermal Systems Ltd
• Univ Osaka City
• Newjec Inc
• Kansai Electric Power Co
• Morikawa Sakusen Ind Co Ltd

Inventors

• Sakai Masanobu
• Fuchimoto Takeshi
• SAI Rinnichi
• Nakao Masaki
• Nakamura Kazuhiro
• Nakaso Yasuhisa
• Morikawa Toshihide
• SAKAE Shinsuke

Classifications

• Y02E10/10

  Geothermal energy · CPC title

• F24T10/20 Primary

  using underground water as working fluid; using working fluid injected directly into the ground, e.g. using injection wells and recovery wells · CPC title

• F24T2010/56

  Control arrangements · CPC title