JP2000027177A - Aquifer thermal storage method utilizing underground continuous wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a large-scale storage capacity and to reduce construction cost with range of application enlarged by a method wherein an artificial aquifer preventing flow of groundwater is formed with underground continuous walls reaching an imperme able layer forming an aquifer, and an underground warm water layer and an under ground cold water layer are formed at the artificial aquifer. SOLUTION: With a natural aquifer 2 including groundwater on an impermeable layer 3 closed, being surrounded with underground continuous walls, an artificial aquifer A preventing flow of groundwater is formed. One of two walls reaching the aquifer A is made to server as a hot water well 5a and another is made to serve as a cold water well 5b, and thereby an underground hot water layer and an underground cold water layer are formed in the artificial aquifer A. In the wintertime, groundwater pumped up through the hot water well 5a is utilized as a thermal source for facilities 7 to be used, and the water cooled down after being utilized is injected into the artificial aquifer A through the cold water well 5b. In the summertime, grondwater pumped up through the cold water well 5b is utilized as a cooling source for the facilities 7 to be used, and the water warmed up after being utilized is injected into the artificial aquifer A through the hot water well 5a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aquifer heat storage method using underground continuous walls, and more particularly to a technique for expanding an applicable area and reducing construction costs.

[0002]

2. Description of the Related Art Conventionally, as a basic system for utilizing the heat of groundwater, hot and cold water is stored in a natural underground aquifer containing groundwater with a low flow velocity, and the groundwater is used in winter. The pumped groundwater is used as a heat source, and the cooled water after use is injected into a cold groundwater layer.In summer, the groundwater pumped from the cold groundwater layer is used as a cold heat source and the warmed water after use is used. Injection into the underground warm water layer (Japanese Patent Publication No. 58-11529) is known.

[0003] Further, the above-mentioned method of utilizing groundwater is further advanced, and the bottom and sides of a natural aquifer are surrounded by a clay layer or other impervious layer, and the inside is filled with gravel (Japanese Patent No. 2684968). Official Gazette) and in an unconfined aquifer where groundwater with a relatively large flow velocity exists, a water-stop wall that reaches the impermeable layer that forms the lower layer of the unconfined aquifer is provided to reduce the flow of groundwater. An artificial aquifer is also known, such as a method of damming and providing a groundwater reservoir (Japanese Patent Application Laid-Open No. 9-159228).

[0004]

However, according to the conventional method of storing heat using a natural aquifer as described above, if the flow rate of groundwater in the natural aquifer is not sufficiently small, Hot water as a heat source or cold water as a cold heat source cannot be kept at an appropriate position in the aquifer, and each water moves, resulting in a gradual heat transfer and heat diffusion. Therefore, maintain the cold heat of cold water injected in winter until summer,
It becomes difficult to maintain the heat of the hot water injected in summer until winter.

[0005] For this reason, in areas where heat can be stored using a natural aquifer, there is a confined aquifer that often has a large amount of water and a groundwater vein with a very small flow velocity. The range is easily limited, and it is difficult to apply a groundwater utilization system using a natural aquifer to an area where there is no aquifer as described above.

[0006] In addition, since the depth of the confined aquifer is generally large, a deep well is required, and there is a disadvantage that the construction of the well requires a great deal of cost and construction time.

On the other hand, if an unconfined aquifer having free groundwater, which often has a high flow velocity, is to be used, the construction of the well is easy because the unconfined aquifer exists in a relatively shallow region. However, it is necessary to form a completely artificial aquifer by providing a water stop wall in order to suppress the flow of groundwater as in the past, and it is unavoidable to increase construction costs.

Further, according to any of the above conventional methods,
The area of application depends on the presence or absence of an appropriate aquifer and the size and area of such aquifer.In addition, the scale of the aquifer existing underground in a limited area naturally increases the heat storage capacity. Due to limitations, it was difficult to use large-scale and efficient groundwater heat over the seasons.

Accordingly, the present invention has been made in view of such a conventional problem, and in the aquifer heat storage method using the underground continuous wall, the application area of such a usage method has been expanded as compared with the related art. It is another object of the present invention to secure a large-scale heat storage capacity and reduce the construction cost of a groundwater heat utilization system.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and has a structure in which a stratum having an aquifer reaches an impermeable layer which forms a lower layer of the aquifer. An intermediate aquifer is provided under the ground to form an artificial aquifer in which the flow of groundwater is suppressed, and the underground warm water layer and the underground cold water layer are formed in the artificial aquifer.

Further, if water is injected into a region surrounded by the impermeable layer and the underground continuous wall to form the artificial aquifer,
This is suitable when the amount of groundwater in the aquifer is insufficient or when the aquifer itself does not exist.

Further, the artificial aquifer is surrounded by an impermeable layer at a bottom portion and a continuous underground wall at a side portion, and is further provided at a lowermost slab or impermeable layer immediately above the building. Is preferably formed as a closed space whose upper part is closed.

[0013]

FIG. 1 shows an example of an embodiment of the present invention.
Is shown in In FIG. 1, an impermeable layer 3 existing in the ground forms a lower layer of the natural aquifer 2, the natural aquifer 2 is in the formation above the impermeable layer 3 and has groundwater, and The artificial aquifer A in which the groundwater flow is suppressed is formed by, for example, closing the entire periphery of the natural aquifer 2 with the underground continuous wall 4. In the present embodiment, as an example, the underground continuous wall 4 plays a role of supporting a structure existing on the ground, the lowermost portion of the underground continuous wall 4 reaches the water-impermeable layer 3 as a supporting ground, and the wall head is formed of the structure. One connected to the slab 1 is given.

Here, the underground continuous wall 4 does not have to use a member that plays a role of supporting the above-ground structure, and is newly constructed around the above-mentioned above-ground structure to carry out the heat storage method of the present invention. May be used.

Further, the water-impermeable layer 3 is not necessarily limited to the supporting ground of the underground continuous wall. For example, if the supporting ground does not have water-impermeable, the water-impermeable layer existing thereabove is appropriately used. It is possible to

In forming the artificial aquifer A, it is not always necessary to close the entire periphery of the natural aquifer 2 with the underground continuous wall 4, for example, only on the downstream side in the direction of groundwater movement. The underground continuous wall 4 may be closed in such a way that the underground continuous wall 4 suppresses the movement of the groundwater.

In order to carry out the heat storage method of the present invention, first, two wells 5a, 5a and 5a reaching the artificial aquifer A described above.
b is sufficiently separated, and one is a hot water well 5a and the other is a cold water well 5b as described later.

Thus, the underground hot water layer and the underground cold water layer in the above-mentioned underground water heat utilization system are formed in the artificial aquifer 2.

Here, regarding the alternate use of the hot water well 5a and the cold water well 5b in winter and summer, in winter,
The groundwater pumped from the hot water well 5a by the water pump 6a is guided to the above ground facility 7, and the groundwater is used as a heat source for heating (for example, passed through an evaporator of a heating heat pump), and further used as a heat source. After the cooled groundwater is drained from the other cold water well 5b, the artificial aquifer A
Inject into With this, the underground cold water layer 8 around the cold water well 5b
b will be formed.

On the other hand, in the summer, the groundwater pumped from the cold water well 5b by the pump 6b is used by the above-mentioned utilization facilities 7 on the ground.
The cold water is used as a cold heat source for cooling or the like (for example, passed through a condenser of a cooling heat pump), and the warm ground water used as the cold heat source is supplied from the other hot water well 5a to the artificial water supply. Inject into layer A. Thus, the underground hot water layer 8a is formed around the hot water well 5a.

In this embodiment, an example in which natural groundwater is present in the stratum between the slab 1 and the impermeable layer 3 below the above-ground structure has been described, but groundwater has been present in the stratum from the beginning. If not, or if there is not enough water even if present, the impermeable layer 3 and the underground continuous wall 4
It is preferable that water is injected into a region surrounded by the above and the artificial aquifer A is formed.

In addition, as a method of injecting heat into the artificial aquifer A, the entire system is controlled so that heating and cooling are balanced throughout the year, and heat is applied by using groundwater for heat exchange over a long period of time. It can also be managed so as not to affect the surrounding environment.

Further, the upper layer of the artificial aquifer A is not necessarily limited to the slab 1 of the above-ground structure, and any impermeable material such as a clay layer can be appropriately used.

[0024]

As described above in detail, according to the aquifer thermal storage method using the underground continuous wall of the present invention, regardless of the presence or absence of a sufficient amount of groundwater in the ground and the magnitude of the groundwater flow velocity. Since artificial aquifers can be easily formed, the geographical limitation of construction due to the current state of groundwater, such as the presence or absence of groundwater and the magnitude of flow velocity, is eliminated, and the application of aquifer thermal storage method The region can be expanded to a wide range.

[0025] Further, regarding the formation of the artificial aquifer in the present invention, it is not necessary to take measures such as constructing a new structure in the stratum other than the construction of the underground continuous wall. The construction cost can be reduced compared to the case where an aquifer is formed artificially, and the formation range of the aquifer can be made much larger simply by adjusting the construction position of the underground continuous wall. Therefore, a large-scale heat storage capacity can be expected.

In addition, the construction cost is further reduced if the aquifer thermal storage method of the present invention is applied immediately below a structure where an underground continuous wall is planned to be constructed from the initial schedule. Becomes

Furthermore, not only immediately below a single structure,
An underground continuous wall according to the present invention is also constructed immediately below a plurality of adjacent structures, and the underground continuous wall, the lowermost slab and pavement of each structure, and the impermeable layer are closed and integrated. If the artificial aquifer is formed, the present invention can be applied to a larger scale and a wider range.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment of the present invention.

[Explanation of symbols]

 A artificial aquifer 1 slab 2 natural aquifer 3 impermeable layer 4 underground continuous wall 5a hot water well 5b cold water well 6a, 6b pumping pump 7 utilization equipment 8a underground hot water layer 8b underground cold water layer

Claims (2)

[Claims] In the winter, groundwater pumped from an underground hot water layer is used as a heat source, and cooled water used is injected into an underground cold water layer. In summer, the groundwater pumped from the underground cold water layer is used as the underground water. In the method of utilizing the heat of groundwater injected into a warm water layer, an underground continuous wall that reaches the impermeable layer that forms the lower layer of the aquifer is formed in the formation with the aquifer, thereby suppressing the flow of groundwater Forming an artificial aquifer formed underground, and forming the underground warm water layer and the underground cold water layer in the artificial aquifer using an underground continuous wall. . 2. The underground continuous wall according to claim 1, wherein water is injected into a region surrounded by the impermeable layer and the underground continuous wall to form the artificial aquifer. Aquifer thermal storage method.