JP7307949B2 - Geothermal heat utilization equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a geothermal heat utilization apparatus that uses the heat of underground water as a heat source (including a heat source and a cold heat source) for snow melting, air conditioners, refrigerators, and the like.

Conventionally, in this type of invention, for example, as described in Patent Document 1, a vertical casing, a forward pipe extending from an opening located in the casing to the outside of the upper casing, and a It is provided with a return pipe that enters the casing and extends downward, and after the groundwater in the casing is pumped up by the outgoing pipe and circulated to the ground equipment and used for heat exchange, etc., the water after use is discharged through the return pipe to the casing. There is an underground water circulation device that returns water inside and further returns it to the underground water vein.

JP-A-2006-9335

By the way, according to the above-mentioned prior art, since the pumped groundwater is returned to the groundwater vein after being used in the ground equipment, there are concerns about adverse effects on the environment, and there are cases where it is subject to regulation by local governments and the like.
Therefore, it is proposed to provide a heat exchanger that exchanges heat with the groundwater in a state that is cut off from the groundwater in the casing, and to circulate the heat medium fluid in this heat exchanger to the ground equipment.
However, in such a configuration, the underground water may remain in the casing and the temperature may rise or drop, making it impossible to perform efficient heat exchange.

In order to solve at least part of the above problems, the present invention has the following configurations.
In geothermal heat utilization equipment that utilizes the heat of groundwater in ground facilities,
A vertical cylindrical casing having a water passage hole for circulating groundwater on the lower end side, and a heat medium fluid circulating in the pipe and the groundwater in contact with the outer wall of the pipe, which is provided so as to be immersed in the groundwater stored in the casing. a heat exchanger that exchanges heat between the heat exchanger and the ground equipment, a heat medium transfer pipe that is connected so that the heat medium fluid is circulated by a circulation pump between the heat exchanger and the ground equipment, and the inside of the casing A geothermal heat utilization apparatus comprising a pressurization and decompression device that applies pressure from above to groundwater stored in the underground water and removes the pressure , and the pressurization and decompression device is a compressor that sends gas. bottom.

Since the present invention is configured as described above, it is possible to efficiently utilize the heat of the groundwater without pumping up or returning the groundwater.

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional view which shows typically the state buried in the ground about an example of the geothermal heat utilization apparatus which concerns on this invention. FIG. 3 is a vertical cross-sectional view schematically showing another example of the geothermal heat utilization device according to the present invention, buried in the ground. FIG. 3 is a vertical cross-sectional view schematically showing another example of the geothermal heat utilization device according to the present invention, buried in the ground.

The present embodiment discloses the following features.
A first feature is a geothermal heat utilization device that utilizes the heat of groundwater in ground equipment, and includes a vertical cylindrical casing having a water passage port for circulating groundwater on the lower end side, and A heat exchanger provided so as to be immersed in the stored groundwater for exchanging heat between the heat medium fluid flowing in the pipe and the groundwater in contact with the outer wall of the pipe, and between the heat exchanger and the ground equipment. a heat medium transfer pipe connected to circulate the heat medium fluid, and a pressurization/decompression device that applies pressure from above to the groundwater stored in the casing and removes the pressure. (See FIGS. 1-3).

As a second feature, the upper side of the water passage in the casing is surrounded by a peripheral wall of the casing, a lid member that closes the upper end side of the casing, and a surface of groundwater that has entered the casing. A sealed space is formed, and the pressurization/decompression device feeds a fluid into the sealed space to pressurize it or depressurize the fluid (see FIGS. 1 to 3).

As a third feature, the pressurization/decompression device is connected to a pressurized fluid pipe having a discharge port above the water surface of groundwater stored in the casing, and a fluid is sent upstream of the pressurized fluid pipe. and a compressor (see FIGS. 1-2).

A fourth feature is that a floating member is provided on the water surface of the groundwater stored in the casing so as to cover the water surface (see FIG. 1).

A fifth feature is that the casing, the heat exchanger, and the heat medium transfer pipe constitute a geothermal heat utilization unit, a plurality of the geothermal heat utilization units are arranged in parallel, and the plurality of underground heat utilization units are arranged in parallel. Among the heat utilization units, any one of the geothermal heat utilization units is provided with the pressurization/decompression device, and a closed space above the water surface of the groundwater in the casing of this geothermal heat utilization unit and other adjacent underground A pressure equalizing pipe was provided between the sealed space above the groundwater in the casing of the heat utilization unit to circulate the fluid and equalize the pressure (see Fig. 2).

As a sixth feature, the pressurization/decompression device includes a floating member provided so as to cover the water surface of groundwater stored in the casing, and a floating member that pushes downward or releases the pushing force. (See FIG. 3).

<First Embodiment>
Next, an embodiment having the above features will be described in detail with reference to the drawings.

FIG. 1 shows a state in which a geothermal heat utilization device 1 according to the present invention is embedded in the ground having an impermeable layer and an aquifer.
An aquifer is a stratum containing water formed between upper and lower impermeable layers. It is composed of conglomerate, rarely basalt, igneous layers of interspersed lava, or layers of porous, hollow limestone.

The geothermal heat utilization device 1 is embedded so that its lower end reaches an aquifer having a target temperature, water volume, etc., and is configured to utilize the heat of the groundwater in the aquifer in the ground equipment X.

To explain in detail, this geothermal heat utilization apparatus 1 comprises a vertical bottomed cylindrical casing 10 having a water passage 11 for circulating groundwater on the lower end side, and a casing 10 immersed in the groundwater stored in the casing 10 . A heat exchanger 20 that exchanges heat between the heat medium fluid flowing in the pipe and the groundwater that is in contact with the outer wall of the pipe, and the heat medium fluid ( a heat medium transfer pipe 30 connected to circulate antifreeze liquid, etc.), and a pressurization/decompression device 40 for applying pressure from above to the groundwater W stored in the casing 10 and for removing the pressure. is equipped with

The ground equipment X is, for example, a snow melting device embedded under the road surface to melt snow on the road surface, and is formed by bending a pipe having an inlet and an outlet in a serpentine or meandering shape along the road surface. In addition, FIG. 1 schematically shows a toguro-shaped pipe.
Other examples of ground equipment X include a heat exchanger that recovers heat from the road surface, an air conditioner such as a heat pump chiller, or a refrigerator. is connected to the heat medium transport pipe 30 .

The casing 10 is a long cylindrical member with a bottom, and is configured by connecting a plurality of cylindrical metal pipes in the vertical direction and connecting the bottom to the lowest end.
The upper end of the casing 10 is airtightly closed by a disk-shaped lid member 13 through which a heat medium carrier pipe 30 and the like, which will be described later, are inserted.
The lower end wall forming the bottom of the casing 10, as shown in FIG. 1, is in contact with a subterranean layer (impermeable layer in the illustrated example).

The diameter of the casing 10 is appropriately selected from, for example, 100 mm, 125 mm, 150 mm, 200 mm, 300 mm, etc., according to the required circulation amount.
A water passage port 11 is provided on the lower end side of the casing 10 at a position corresponding to at least a part of the target aquifer.

The water flow port 11 is a vertically long slit-like through-hole that penetrates the peripheral wall of the casing 10 in the radial direction and extends in the vertical direction, and is sometimes called a strainer.
A plurality of water passage ports 11 are provided on the peripheral wall of the casing 10 at intervals in the circumferential direction.
The width dimension (circumferential dimension) of each water passage 11 is appropriately set so as to make it difficult for pebbles (pebbles) in the aquifer to pass through.
In addition, as other examples of the water flow port 11, it is also possible to adopt a mode composed of a large number of small holes or a mode composed of a fibrous material through which water can pass.

A closed space S surrounded by a peripheral wall of the casing 10, a cover member 13 that closes the upper end of the casing 10, and the water surface of the groundwater W that has entered the casing 10 is formed above the water passage 11 in the casing 10. be done. Pressurized fluid is fed into this closed space S by a pressure reducing device 40, which will be described later, or the pressure of the fluid is reduced.

The heat exchanger 20 is a coil-type heat exchanger in which a heat transfer tube 21 is wound into a coil. , the coiled heat transfer tube 21 and then discharged from the outlet 23 .
This heat exchanger 20 is provided so as to be submerged in the groundwater W within the casing 10 .
Note that the heat exchanger 20 may be one other than the illustrated example as long as it separates the heat medium fluid flowing inside and the groundwater W outside and exchanges heat between them. .

The heat medium fluid flowing through the heat exchanger 20 is, for example, antifreeze used as cooling water for refrigeration equipment, air conditioning equipment, etc., and is sometimes called brine or the like.
Other examples of this heat carrier fluid include water and other fluids.

The heat medium transport pipe 30 includes a forward pipe 31 leading from the heat exchanger 20 to the ground facility X and a return pipe 32 leading from the ground facility X to the heat exchanger 20, and constitutes a circulating piping route.

The forward pipe 31 and the return pipe 32 are configured by cylindrical pipes, tubes, or the like.
One end of the forward pipe 31 is connected to the outlet 23 of the heat exchanger 20, and the other end is extended upward, inserted through the cover member 13, and connected to the inlet of the ground equipment X. .
A circulation pump P for forcibly conveying the internal heat medium fluid, a pressure gauge, a thermometer, etc., not shown, are provided in the middle of the forward pipe 31 .

One end of the return pipe 32 is connected to the outlet of the ground facility X, and the other end is inserted through the lid member 13 and extends downward within the casing 10 to connect to the inlet 22 of the heat exchanger 20. ing.

The pressurization/decompression device 40 includes a pressurized fluid pipe 41 having a discharge port 41a above the surface of the groundwater W stored in the casing 10, and a compressor C for forcibly feeding the fluid to the upstream side of the pressurized fluid pipe 41. Equipped with

Here, the fluid may be ground air, but inert gas (such as nitrogen), gas other than air, or liquid having a lower specific gravity than water (such as oil) may also be used. be.

The pressurized fluid pipe 41 is composed of a cylindrical pipe, tube, or the like, one end of which is inserted into the casing 10 via the cover member 13, and the opening of the other end of which is connected to the discharge port of the compressor C. are doing.

The compressor C is, for example, an air compressor, and is configured to pressurize the fluid in the pressurized fluid pipe 41 during operation and reduce the pressure in the pressurized fluid pipe 41 when stopped.
This compressor C is controlled to repeat starting and stopping at appropriate intervals. That is, the compressor C is controlled to alternately repeat an interval in which the closed space S is pressurized by operation for a predetermined time and an interval in which the operation is stopped for a predetermined time to depressurize the closed space S. The pressure of the fluid in pressurized fluid tube 41 is varied.
As another example, a motor-operated valve or a solenoid valve may be provided on the pressurized fluid pipe 41, the compressor C may continue to operate without starting and stopping, and the pressure inside the pressurized fluid pipe 41 may be controlled by turning the motor-operated valve or the solenoid valve on and off. You may make it fluctuate the pressure of the fluid of.

A lid member 13 that closes the upper end side of the casing 10 is a disk-shaped member and is airtightly connected to the upper end edge of the casing 10 .
As described above, pipes such as the forward pipe 31, the return pipe 32, and the pressurized fluid pipe 41 are inserted through the lid member 13, and the inserted portions are airtight so as to maintain the airtightness of the sealed space S. being processed.

Next, the characteristic functions and effects of the geothermal heat utilization apparatus 1 having the above configuration will be described in detail.
In the underground heat utilization device 1, when the casing 10 is buried in the ground so that the water passages 11 are arranged in the aquifer, the groundwater of the aquifer flows into the casing 10 through the plurality of water passages 11. Infiltrate.

As a result, the groundwater W accumulates in the lower half of the casing 10, and the heat transfer tubes 21 are submerged in the groundwater W. When the circulation pump P is operated in this state, the heat medium fluid circulates through the circulation path including the forward pipe 31, the heat exchanger 20, the ground facility X, the return pipe 32, and the like.
Then, on the heat exchanger 20 side, the heat of the groundwater W in the casing 10 is transferred to the heat medium fluid in the heat exchanger 20, and on the ground side, the heat of the heat medium fluid circulated to the ground facility X is utilized. .

On the other hand, a sealed space S is formed above the water surface of the groundwater W in the casing 10 , and pressurized fluid is supplied to the sealed space S by the pressurization/decompression device 40 .

Since the pressurization/decompression device 40 is turned on and off at predetermined intervals, the fluid in the closed space S is repeatedly pressurized and depressurized, and the surface of the groundwater W fluctuates up and down.
Therefore, the interval at which the groundwater W in the casing 10 is returned to the aquifer due to the pressurization and the interval at which the groundwater enters the casing 10 from the aquifer due to the decompression are alternately repeated. Groundwater W stored in 10 is appropriately agitated and flows.

In particular, in the present embodiment, since the discharge port 41a of the pressurized fluid pipe 41 of the pressurization/decompression device 40 is arranged above the water surface of the groundwater W stored in the casing 10, pressure fluctuations in the sealed space S are suppressed. It can be effectively transmitted to the groundwater W.
That is, if the discharge port 41a is immersed in the groundwater W in the casing 10, a large amount of bubbles are generated by the gas discharged into the groundwater W, and the pressure fluctuations in the closed space S are affected by these bubbles. However, according to this embodiment, it is possible to solve such a problem.

Therefore, according to the geothermal heat utilization apparatus 1 according to the present invention, the groundwater heat can be indirectly utilized without pumping up the groundwater W to the ground or returning it to the ground. The temperature of the groundwater W in the casing 10 can be stabilized. Therefore, the ground facility X can obtain groundwater heat at a stable temperature.
The groundwater heat obtained by the ground facility X is effectively used as a heat source for snow melting, air conditioners, refrigerators, etc. (including both hot and cold heat sources).
It is also possible to exhaust the heat absorbed by the ground equipment X to the groundwater side via the heat exchanger 20 .

In addition, you may provide the floating member 50 in the said underground heat utilization apparatus 1 as needed.
The floating member 50 is a substantially disc-shaped member that floats on the surface of the groundwater W. As shown in FIG. The floating member 50 is made of a material having buoyancy, such as a hollow material, and is formed in a disk shape that covers the water surface of the groundwater W, and has through holes into which the forward pipe 31 and the return pipe 32 are loosely inserted.
According to this floating member 50, the fluctuation of the fluid in the sealed space S caused by the compressor C can be efficiently transmitted to the groundwater W, and the groundwater W stored in the casing 10 can be more effectively agitated and its temperature can be stabilized.

<Second embodiment>
Next, another embodiment according to the present invention will be described in detail based on the drawings. In addition, since the embodiment shown below is obtained by partially changing the geothermal heat utilization apparatus 1, the changed part will be mainly described in detail, and redundant detailed description will be omitted.

The geothermal heat utilization device 2 shown in FIG. 2 comprises a casing 10, a heat exchanger 20, and a heat medium transfer pipe 30 to constitute a geothermal heat utilization unit, and a plurality of the geothermal heat utilization units are arranged in parallel. ing.
A pressurization/decompression device 40 is provided in any one of the geothermal heat utilization units A and B (two in the illustrated example).
A sealed space S above the surface of the groundwater W in the casing 10 of the geothermal heat utilization unit A and a sealed space S above the groundwater W in the casing 10 of the adjacent geothermal heat utilization unit B A pressure equalizing pipe 60 for circulating the fluid to equalize the pressure is provided between and. The geothermal heat utilization unit B is not equipped with the pressurization/decompression device 40 .

The pressure equalizing pipe 60 is a pipe made of metal, synthetic resin, or the like. The other end is inserted into the lid member 13 of the other geothermal heat utilization unit B and placed in the closed space S above the groundwater level in the casing 10 .

Therefore, according to the geothermal heat utilization device 2 configured as described above, by repeating pressurization and depressurization by the pressurization/decompression device 40, pressure fluctuations in one sealed space S can be transmitted to the other sealed space S. Furthermore, with a simple structure, the temperature of the groundwater W in the casing 10 is stabilized in each of the plurality of geothermal heat utilization units A and B, and the groundwater heat at a stable temperature is generated in the corresponding ground facility X. Obtainable.

<Third embodiment>
A geothermal heat utilization device 3 shown in FIG.

The pressurization/decompression device 70 includes a floating member 71 provided so as to cover the water surface of the groundwater W stored in the casing 10, and a pushing member for pushing the floating member 71 downward or releasing the pushing force. device 72;

The floating member 71 is a substantially disc-shaped member that floats on the surface of the groundwater W. As shown in FIG. The floating member 50 is made of a material having buoyancy, such as a hollow material, and is formed in a disk shape that covers the water surface of the groundwater W, and the forward pipe 31 and the return pipe 32 are loosely inserted therein.

The pushing device 72 includes a rod-shaped member 72a vertically connected to the center of the upper surface of the floating member 71, a piston 72b connected to the upper end of the rod-shaped member 72a, and sliding contact with the outer peripheral surface of the piston 72b. It comprises a cylindrical cylinder 72c that supports the piston 72b so as to be able to move up and down, and a pressurized fluid pipe 72d and a compressor C that feed fluid into the upper space in the cylinder 72c.

The cylinder 72c is supported by the cover member 13, the inner peripheral surface of the casing 10, or other immovable portions, and the upper end portion thereof is sealed by the cover member 13. As shown in FIG.
The pressurized fluid pipe 72d has one end having an opening inserted through the lid member 13 and is arranged in the upper space inside the piston 72b. The opening at the other end of the pressurized fluid pipe 72d is connected to the discharge port of the compressor C. As shown in FIG.

The pressurized fluid pipe 72d is composed of a cylindrical pipe, tube, or the like, one end of which is inserted into the cylinder 72c via the cover member 13, and the opening of the other end is connected to the discharge port of the compressor C. are doing.

Therefore, according to the geothermal heat utilization device 3 shown in FIG. communicate effectively.
Therefore, the groundwater W stored in the casing 10 can be more effectively agitated, and the temperature of the groundwater W in the casing 10 can be stabilized, and the groundwater at a stable temperature can be generated at the corresponding ground equipment X. You can get heat.

The pushing device 72 vertically moves the floating member 71 and the rod-shaped member 72a by the fluid pressure of the compressor C. Other examples of this pushing device include a linear drive mechanism using a rack and pinion, It is also possible to adopt a mode in which the floating member 71 and the rod-shaped member 72a are moved up and down by an electromagnetic driving device using an electromagnet.

Moreover, the present invention is not limited to the embodiments described above, and can be modified as appropriate without changing the gist of the present invention.

Reference Signs List 1, 2, 3: Geothermal heat utilization device 10: Casing 11: Water passage port 13: Lid member 20: Heat exchanger 30: Heat medium transfer pipe 40, 70: Pressure reducing device 41, 72d: Pressurized fluid pipe 50, 71: Floating member 72a: Rod-shaped member 72b: Piston 72c: Cylinder 60: Pressure equalizing pipe Geothermal heat utilization units A, B
C: Compressor P: Circulation pump S: Closed space W: Underground water X: Ground equipment

Claims (6)

In geothermal heat utilization equipment that utilizes the heat of groundwater in ground facilities,
A vertical cylindrical casing having a water passage hole for circulating groundwater on the lower end side;
a heat exchanger that is provided so as to be immersed in the groundwater stored in the casing and exchanges heat between the heat medium fluid flowing in the pipe and the groundwater in contact with the outer wall of the pipe;
a heat medium transfer pipe connected by piping so that the heat medium fluid is circulated between the heat exchanger and the ground facility by a circulation pump ;
a pressurizing and depressurizing device that applies pressure from above to the groundwater stored in the casing and removes the pressure ;
A geothermal heat utilization device, wherein the pressurization/decompression device is a compressor for sending gas .
A closed space surrounded by a peripheral wall of the casing, a lid member that closes the upper end side of the casing, and the surface of groundwater that has entered the casing is formed above the water passage in the casing,
2. The geothermal heat utilization apparatus according to claim 1, wherein the pressurization/decompression device feeds a fluid into the sealed space to pressurize or depressurize the fluid.
The pressurization/decompression device includes a pressurized fluid pipe having a discharge port above the surface of the groundwater stored in the casing, and a compressor connected to the upstream side of the pressurized fluid pipe so as to feed the fluid. 3. The geothermal heat utilization apparatus according to claim 2, characterized in that:
4. The geothermal heat utilization apparatus according to claim 2, wherein a floating member is provided on the water surface of the groundwater stored in the casing so as to cover the water surface.
A geothermal heat utilization unit is configured by comprising the casing, the heat exchanger, and the heat medium transfer pipe, and a plurality of the geothermal heat utilization units are arranged in parallel,
Any one of the plurality of geothermal heat utilization units is provided with the pressurization/decompression device, and a sealed space above the surface of the groundwater in the casing of the geothermal heat utilization unit is adjacent to the A pressure equalizing pipe is provided between the sealed space above the groundwater in the casing of the other geothermal heat utilization unit to circulate the fluid and equalize the pressure. A geothermal heat utilization device according to any one of the preceding paragraphs.
In geothermal heat utilization equipment that utilizes the heat of groundwater in ground facilities,
A vertical cylindrical casing having a water passage hole for circulating groundwater on the lower end side;
a heat exchanger that is provided so as to be immersed in the groundwater stored in the casing and exchanges heat between the heat medium fluid flowing in the pipe and the groundwater in contact with the outer wall of the pipe;
a heat medium transfer pipe connected by piping so as to circulate the heat medium fluid between the heat exchanger and the ground facility;
a pressurizing and depressurizing device that applies pressure from above to the groundwater stored in the casing and removes the pressure;
The pressurization/decompression device includes a floating member provided so as to cover the water surface of the groundwater stored in the casing, and a pushing device for pushing the floating member downward and releasing the pushing force. A geothermal heat utilization device comprising:

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