Thermal energy storage with an expansion space

• US 9,823,026 B2
• Filed: 11/01/2013
• Issued: 11/21/2017
• Est. Priority Date: 11/01/2012
• Status: Expired due to Fees

• Current Assignee: Skanska Sverige AB (Skanska AB)
• Original Assignee: Skanska Sverige AB (Skanska AB)
• Inventors: Pilebro, Hans
• Primary Examiner(s): CIRIC, LJILJANA V
• Application Number:
  US14/439,748
• Publication Number:
  US 20150354903A1
• Time in Patent Office: 1,481 Days
• CPC Class Codes: B65G 5/00 Storing fluids in natural or artificial cavities or chambers in the earth
• CPC Class Codes: F28D 20/0043 specially adapted for long-term heat storage; Underground tanks; Floating reservoirs; Pools; Ponds F28D20/0052 takes precedence
• CPC Class Codes: F28D 20/0052 using the ground body or aquifers as heat storage medium
• CPC Class Codes: F28D 2020/006 Heat storage systems not otherwise provided for
• CPC Class Codes: Y02E 10/10 Geothermal energy
• CPC Class Codes: Y02E 60/14 Thermal energy storage

Abstract

An arrangement for storing thermal energy, including a shaft (1) and at least one tunnel (2), the shaft (1) and the tunnel (2) being in fluid communication with each other. The tunnel (2) includes at least a first (2a), a second (2b), and a third (2c) tunnel section. The second tunnel section (2b) is arranged between and connected to the first (2a) and third (2c) tunnel sections. The second tunnel section (2b) is sealed off at an end (4) connected to the third tunnel section (2c), and the third tunnel section is further connected the shaft (1). The shaft (1) and first (2a) and third (2c) tunnel sections hold fluid for thermal storage. The second tunnel section (2b) is an expansion space should a volume of the fluid expand beyond a volume of the shaft (1) and the first (2a) and third (2c) tunnel sections.

Claims

1. An arrangement for storing thermal energy, comprising

a shaft (1) and at least one tunnel (2),

said shaft (1) and said at least one tunnel (2) being in fluid communication with each other,

said at least one tunnel (2) comprising at least a first tunnel section (2a), a second tunnel section (2b) comprising a second tunnel section first end and a second tunnel section second end (4), and a third tunnel section (2c),

said second tunnel section (2b) being arranged between and connected to said first tunnel section (2a) at said second tunnel section first end and directly connected to said third tunnel section (2c) at said second tunnel section second end (4),

said second tunnel section (2b) being sealed off impermeably at said second tunnel section second end (4) such that no fluid can pass directly from said second tunnel section to said third tunnel section (2c) at said second tunnel section second end (4), and said third tunnel section (2c) further being connected to said shaft (1),

said shaft (1) and first (2a) and third (2c) tunnel sections being adapted for holding a fluid for thermal storage,

said arrangement further comprising a first transfer means (5) for passing excess fluid from said shaft (1) or said third tunnel section (2c) into said first tunnel section (2a),

and a second transfer means (6) for passing excess fluid from said first tunnel section (2a) to said second tunnel section (2b) so that second tunnel section (2b) may receive excess fluid from said first tunnel section (2a);

the arrangement further comprising a separate machine room and a third transfer means (7) connecting said machine room (3) to said second tunnel section (2b).

2. The arrangement according to claim 1, wherein said first transfer means (5) comprises a pipe or a channel.

3. The arrangement according to claim 1, wherein said second transfer means (6) comprises a pipe, a channel, a partial wall, or a one-way valve.

4. The arrangement according to claim 1, wherein said third transfer means (7) comprises a pipe or a channel.

5. The arrangement according to claim 1, further comprising a pump (8) configured to pass an amount of fluid from said second tunnel section (2b) to said first tunnel section (2a) should the fluid volume in said first tunnel section (2a) fall below a predetermined limit value.

6. The arrangement according to claim 1, wherein said shaft (1) extends vertically and said tunnel (2) is arranged such that it surrounds the shaft (1) in the form of a helix spiral from the top to the bottom of the shaft (1).

7. The arrangement according to claim 1, wherein said second transfer means (6) comprises a partial wall.

8. The arrangement according to claim 1, wherein said second transfer means (6) comprises a one-way valve.

9. A method of storing thermal energy comprising

providing the arrangement of claim 1;

disposing fluid for thermal energy storage in said shaft (1) and said third tunnel section (2c); and

maintaining fluid in said first (2a) tunnel section (2a) at a predetermined fluid pressure level.

10. The method of claim 9, wherein the fluid is not water and the fluid pressure level in tunnel section (2a) is balanced to a level slightly below the level of the surrounding ground water pressure.

11. The method of claim 9, wherein the fluid is water and the fluid pressure level in tunnel section (2a) is balanced to the level of the surrounding ground water pressure.

12. The method of claim 9, wherein the fluid pressure level in said first tunnel section (2a) is balanced by addition of fluid from said third tunnel section (2c) or said shaft (1);

and removal of fluid from said first tunnel section (2a) to said third tunnel section (2c) or said shaft (1).

13. The method of claim 9, wherein the fluid pressure level in said first tunnel section (2a) is balanced by addition of fluid from said second tunnel section (2b) to said first tunnel section (2a) by a pump (8), by addition of fluid from said third tunnel section (2c) or by addition of fluid from said shaft (1);

and by removal of fluid from said first tunnel section (2a) to said third tunnel section (2c) or said shaft (1).