Underground storage system for fluid storage
An underground storage system for storing fluid includes a hole having a bottom, a support element including at least one opening able to receive a joining element, at least one reservoir having a longitudinal axis, a bottom end and a top end, a first closure able to close the reservoir at its bottom end, and a second closure able to close the reservoir at its top end. The top end is able to be joined to the support element via the joining element such that the reservoir is hung inside the hole and such that an axial clearance able to absorb axial thermal expansion of the reservoir remains between the first closure and the bottom.
1 . An underground storage system for storing fluids, said storage system comprising:
a hole made in a ground, said hole having a bottom;
a support element comprising at least one opening;
a joining element inserted in the opening of the support element;
at least one reservoir, said reservoir having a longitudinal axis, a bottom end closed by a first closure means, and a top end closed by a second closure means;
the joining element being attached to the top end, and
said top end being joined to the support element via the joining element such that the reservoir is hung inside the hole and such that an axial clearance able to absorb axial thermal expansion of said reservoir remains between the first closure means of the reservoir and the bottom of the hole.
2 . The storage system according to claim 1 , wherein the reservoir comprises at least one metal tube, said metal tube having at least one end provided with at least one threaded portion.
3 . The storage system according to claim 1 , wherein the reservoir comprises at least two metal tubes screwed to each other so as to form a column of tubes.
4 . The storage system according to claim 1 , wherein the axial clearance satisfies the following inequality:
G
≥
(
L
2
*
β
*
α
)
+
[
2
0
*
α
*
8
0
*
(
1
-
e
-
0
.
1
1
*
L
)
]
[
Math
1
]
in which: G is a length of the axial clearance expressed in metres, L represents the length of the reservoir expressed in metres, β represents a geothermal gradient expressed in degrees Celsius per metre, and a represents a coefficient of thermal expansion of a metal expressed in metres per degree Celsius.
5 . The storage system according to claim 1 , wherein the first closure means and/or the second closure means is configured to close the reservoir by screw-fastening.
6 . The storage system according to claim 1 , wherein said system comprises a plurality of reservoirs, each reservoir having a longitudinal axis, a bottom end and a top end, said top end of each reservoir being able to be joined to the support element via a joining element such that each reservoir is hung inside the hole.
7 . The storage system according to claim 1 , wherein the hole has at least one casing.
8 . The storage system according to claim 7 , wherein the casing is made of concrete, cement, or steel.
9 . An underground storage method for storing fluids, said method comprising:
making a hole in a ground, said hole having a bottom;
providing a support element comprising at least one opening able to receive a joining element;
providing at least one reservoir, said reservoir having a longitudinal axis, a bottom end and a top end;
providing a first closure means configured to close said reservoir at the bottom end, and a second closure means configured to close the reservoir at the top end; and
joining said top end to the support element via the joining element, and inserting the reservoir and the joining element in the opening such that the reservoir is hung inside the hole and such that an axial clearance able to absorb axial thermal expansion of said reservoir remains between the first closure means of the reservoir and the bottom of the hole.