JP2023133835A - Underground heat exchange device - Google Patents

Abstract

To provide an underground heat exchange device capable of being constructed inexpensively and exhibiting a high heat exchange capacity.SOLUTION: An underground heat exchange device has an underground heat exchanger 110 that exchanges heat between a refrigerant and water stored underground, and uses the refrigerant whose heat has been exchanged in the underground heat exchanger 110 to further exchange heat with a predetermined heat pump device. The underground heat exchange device has a permeation chamber 140 that is excavated from the ground surface with a predetermined volume to store water such as rainwater. A heat exchange pipe through which the refrigerant flows as the underground heat exchanger 110 is disposed along the bottom surface of the permeation chamber 140, as a horizontally buried underground heat exchanger having a plurality of annular parts wound in an annular manner while being shifted so that some parts are preferably overlapped.SELECTED DRAWING: Figure 1

Description

The present invention relates to an underground heat exchange device that uses a refrigerant that has undergone heat exchange with water stored underground (rainwater, groundwater, etc.) in a heat pump cycle of an air conditioner, etc. More specifically, it can be constructed at low cost, and , relates to an underground heat exchange device that exhibits high heat exchange capacity.

For example, as described in Patent Document 1, a general underground heat exchange system has a primary heat exchange circuit in which a primary refrigerant is circulated, and a secondary heat exchange circuit such as an air conditioner. By burying one heat exchanger on the heat exchange circuit side underground and exchanging heat with the secondary heat exchange circuit using the other heat exchanger, the heat generated in the secondary heat exchange circuit and It exchanges heat with underground heat.

Normally, the temperature underground is constant throughout the year (approximately 15 degrees Celsius), so in the summer, the heat from the refrigerant heated by the heat pump cycle is released underground, and in the winter, the cooled refrigerant is heated by geothermal heat. This reduces the load on the compressor provided in the secondary heat exchange circuit, making it possible to save power and significantly reduce _CO2 emissions.

In most cases, the heat exchanger on the primary heat exchange side circulates the primary refrigerant in a heat exchange well with a diameter of about 150 mm that is formed at a depth of about 10 to 200 meters underground in the ground containing groundwater. It is formed by arranging heat exchange pipes (about 30 mm in diameter) and filling the inside of the heat exchange well with sand, gravel, etc. According to this, the inside of the heat exchange well is filled with groundwater, and heat exchange is promoted.

However, since the general groundwater level is approximately 5 to 10 meters underground, the inside of the heat exchange well is filled with water at a location lower than 5 to 10 meters underground, and there is a gap between the ground surface and the groundwater level. In this case, heat exchange is not performed sufficiently.

Another point of view is that in urban areas, much of the ground surface is covered with impermeable layers such as asphalt, and much of the rain that falls on the ground does not permeate into the ground and is returned to the sea via sewers. Groundwater is decreasing due to water leakage.

Therefore, in Patent Document 2, the present applicant provides a water infiltration means for actively infiltrating water such as rainwater into the heat exchange well, and the space of the heat exchange well from the ground surface to the groundwater level is provided. It is proposed to supply water to According to this, the heat exchange efficiency can be further improved, but on the other hand, there is a problem in that drilling a heat exchange well requires a considerable amount of cost per well.

Japanese Patent Application Publication No. 2002-115873 Patent No. 4360690

Therefore, an object of the present invention is to provide an underground heat exchange device that can be constructed at low cost and exhibits high heat exchange ability.

In order to solve the above problems, the present invention includes an underground heat exchanger that exchanges heat between a refrigerant and water stored underground, and the refrigerant is heat-exchanged in the underground heat exchanger. In a geothermal heat exchange device that further exchanges heat with a predetermined heat pump device using
The underground heat exchanger has a permeation tank excavated with a predetermined volume from the ground surface to store water such as rainwater, and the underground heat exchanger is a horizontally buried type, and a heat exchange pipe through which the refrigerant is flowed is installed along the bottom surface of the permeation tank. It is characterized by its placement.

In the present invention, when disposing the heat exchange pipe along the bottom surface of the permeation chamber, it is preferable that one of a spiral type, a meandering type, and a sheet type is selected.

Further, according to a preferred embodiment of the present invention, water supply means is provided for supplying water such as rainwater to the permeation tank.

Further, it is preferable that a water-permeable sheet is provided on the upper surface and inner circumferential surface of the permeation cell.

According to the present invention, it is only necessary to excavate an infiltration tank with a predetermined volume from the ground surface for storing water such as rainwater, and to install a heat exchange pipe through which a refrigerant flows along the bottom of the infiltration tank. Therefore, it is possible to provide a geothermal heat exchange device that can be constructed at low cost and exhibits high heat exchange ability.

FIG. 1 is a schematic diagram showing an embodiment of a geothermal heat exchange device according to the present invention. FIG. 3 is a schematic plan view showing an example of a horizontally buried underground heat exchanger applied to the above-mentioned underground heat exchange device.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited thereto.

Referring to FIG. 1, this underground heat exchange device includes a primary heat exchange circuit 100 that exchanges heat with water such as rainwater, and a part of a predetermined heat pump device (in this example, an air conditioner). The secondary heat exchange circuit 200 is incorporated in the secondary heat exchange circuit 200.

The primary heat exchange circuit 100 is configured between the underground heat exchanger 110, a circulation pipe 120 that circulates the primary refrigerant to the underground heat exchanger 110 via the pump P, and the secondary heat exchange circuit 200. A heat exchanger 130 for performing heat exchange is provided.

As the primary refrigerant used in the primary heat exchange circuit 100, antifreeze is suitable to prevent freezing even in winter, but if the refrigerant does not freeze, such as when the geothermal temperature is high, distilled water etc. may be changed arbitrarily according to the specifications.

The underground heat exchanger 110 is a horizontally buried heat exchanger and is disposed along the bottom surface of a permeation chamber 140 formed from the ground surface with a predetermined volume. In areas where groundwater is abundant, the infiltration chamber 140 is excavated deeper than the groundwater level so that groundwater flows inside, but in normal areas it may be about 1 to 2 meters deep, for example. The infiltration cell 140 may be provided under the floor of a building.

In a preferred embodiment, a water-permeable sheet (water-permeable filter) 141 is provided on the inner circumferential surface (which may include the bottom surface) of the seepage cell 140 to prevent earth and sand from entering the seepage cell 140.

Further, the upper surface of the permeation cell 140 is covered with a water-permeable sheet 142. The permeable sheet 142 applied to the upper surface of the infiltration box 140 is preferably a roadbed made of permeable asphalt, but it may also be made of gravel, permeable blocks, etc., as long as it is basically permeable. It can be arbitrarily selected depending on the situation.

It is preferable that the permeation chamber 140 is filled with gravel, crushed stone, or permeable blocks. According to this, water is stored in the spaces created between gravel. The shape of the infiltration cell 140 may be cylindrical or the like other than the usual square shape, and its volume may also be arbitrarily changed depending on the conditions and specifications of the construction site.

The infiltration cell 140 is provided with a water supply means 160 for actively infiltrating rainwater or the like into the infiltration cell 140. The water supply means 160 includes a drainage pipe 161 that collects and drains rainwater that has fallen on the roof of building B, for example, and a water supply pipe 162 that is connected to the other end of the drainage pipe 161.

In this example, the drainage pipe 161 is connected to a drainage outlet for rainwater, etc. installed on the roof of building B, but it may be installed at a location other than this. Further, it may be connected to a tank that temporarily stores water such as rainwater, a pump that supplies rainwater, a control device thereof, and the like.

Furthermore, it may be connected to a pool or fountain, for example, and the remaining water may be used, or the water drained from factory wastewater or from a fishery facility that uses a lot of water, for example, may be used. Good too.

Referring to FIG. 2, the underground heat exchanger 110 according to the present embodiment is of a spiral type, and has a plurality of annular parts 112 wound around one heat exchange pipe 111 in an annular shape while shifting the heat exchange pipe 111 so that some parts overlap with each other along a plane. It is disposed along the bottom surface of the permeation chamber 140 as a horizontally buried heat exchanger.

For the heat exchange pipe 111, a material with good heat exchange efficiency is preferably used, but a resin pipe is most preferable in consideration of corrosion resistance and weather resistance.

The length Lp of the heat exchange pipe 111 used in the underground heat exchanger 110 is determined by the following formula: d is the diameter of the annular portion 112, P is the pitch (shift amount) of the annular portion 112, and is the length of the underground heat exchanger 110. _L1 is determined by the following equation (1).

According to this, the amount of heat exchange pipes 111 laid per unit area can be increased (more densely laid), so the ability to exchange heat with the water in the permeation chamber 140 is increased. Further, depending on the installation area at the installation site, the necessary amount of units can be manufactured at a factory or the like, compactly packaged, and transported to the installation site.

In addition to the spiral type, the underground heat exchanger 110 may also be of the meandering type, in which heat exchange pipes are tied to wire mesh or the like, similar to floor heating or road heating, or installed between two header pipes. A sheet type formed by connecting a plurality of heat exchange pipes in parallel may also be used.

Referring again to FIG. 1, the secondary heat exchange circuit 200 includes an indoor unit 220 located in building B and an outdoor unit 210 connected to each indoor unit 220, which are dedicated to connected through piping.

The outdoor unit 210 is provided with a refrigeration cycle mechanism (not shown) such as a compressor and a four-way valve inside. The outdoor unit 210 is further provided with a heat exchanger 130 that exchanges heat between the primary heat exchange circuit 100 and the secondary heat exchange circuit 200.

In this example, the heat exchanger 130 performs heat exchange by bringing a metal heat exchange plate with a built-in primary refrigerant pipe into contact with a metal heat exchange plate with a built-in secondary refrigerant pipe. However, it is also possible to place a secondary refrigerant pipe inside the tank storing the primary refrigerant and perform direct heat exchange. The method is not particularly limited.

Furthermore, in this embodiment, the primary heat exchange circuit 100 and the secondary heat exchange circuit 200 mutually exchange heat from rainwater, etc. The underground heat exchanger 110 can also be used as a heat exchanger on the outdoor unit side of the secondary heat exchange circuit 200.

Furthermore, in this embodiment, the secondary heat exchange circuit 200 is incorporated in the refrigeration cycle of a building air conditioning system, but other basic configurations such as a heat pump hot water supply system that perform mutual heat exchange between refrigerant and geothermal heat may also be used. If provided, these modifications are also included in the present invention.

Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the description of the above embodiments. Changes or improvements made to the above-described embodiments by those skilled in the art also fall within the technical scope of the present invention.

1 Air conditioner 100 Primary side heat exchange circuit 110 Geothermal heat exchanger (horizontal geothermal heat exchanger)
111 Heat exchange pipe 112 Annular part 120 Circulation pipe 130 Heat exchanger 140 Penetration cell 141, 142 Water permeable sheet 160 Water supply means 162 Water supply pipe 200 Secondary heat exchange circuit B Building

Claims (4)

It has a geothermal heat exchanger that exchanges heat between a refrigerant and water stored underground, and uses the refrigerant heat-exchanged in the geothermal heat exchanger to connect the refrigerant to a predetermined heat pump device. In underground heat exchange equipment that further exchanges heat,
A permeation tank is excavated from the ground surface with a predetermined volume to store water such as rainwater, and a heat exchange pipe through which the refrigerant is flowed as the underground heat exchanger is arranged along the bottom of the permeation tank. A geothermal heat exchange device featuring: 2. The underground heat exchange device according to claim 1, wherein the heat exchange pipe is arranged in a spiral type, a meandering type, or a sheet type when disposed along the bottom surface of the permeation chamber. The underground heat exchange device according to claim 1 or 2, further comprising a water supply means for supplying water such as rainwater to the infiltration tank. The underground heat exchange device according to any one of claims 1 to 3, wherein a water-permeable sheet is provided on the upper surface and inner circumferential surface of the permeation cell.

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