JP2010133608A - Ground heat exchanger and air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize deterioration of heat exchange capacity even if a crack occurs in an outer pipe 3 due to some cause and a heat carrier in the pipe leaks into the ground in a ground heat exchanger carrying out heat exchange between a refrigerant and soil in the ground via sealed carbon dioxide. <P>SOLUTION: At least one or more bulkheads 6 partitioning a sealed space 7 into a plurality of divided spaces 7a along a pipe axial direction is provided in a pipe interior side of the outer pipe 3 in the ground heat exchanger 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ground heat exchanger for exchanging heat between a heat exchange fluid and soil in the ground, and an air conditioning system using the same.

  2. Description of the Related Art Conventionally, underground heat exchangers that exchange heat between a heat exchange fluid and underground soil via a sealed heat medium are known. This underground heat exchanger is used in, for example, a refrigerant circuit that performs a refrigeration cycle. Patent Document 1 discloses a ground heat exchanger that heats the refrigerant (heat exchange fluid) in the refrigerant circuit using ground heat in heating operation.

  The underground heat exchanger of patent document 1 is comprised with the double tube | pipe type heat exchanger which consists of an outer tube | pipe and the inner tube inserted inside this outer tube | pipe. The inner tube is closed at both ends to form a sealed space inside. The heat medium is sealed in the sealed space. The outer pipe has a refrigerant passage through which the refrigerant of the refrigerant circuit flows.

  The inner pipe is fixed to the inner side of the outer pipe so that the upper and lower ends protrude from the inner side of the outer pipe in the pipe axis direction. The inner pipe protruding downward from the outer pipe is buried in the ground so that the pipe axis direction of the inner pipe is along the vertical direction. That is, the lower part of the inner pipe is in contact with the soil in the ground, and the upper part of the inner pipe is in contact with the refrigerant flowing through the refrigerant passage of the outer pipe.

In such a configuration, when a refrigerant having a temperature lower than that in the ground is caused to flow through the refrigerant flow path, the heat medium vapor and the cold refrigerant that are in the equilibrium vapor pressure at the underground temperature are heated at the upper end side of the inner pipe. The heat medium is exchanged and condensed, and the refrigerant is heated by the heat of condensation. The heat medium condensed and liquefied falls in the inner tube from the upper end side toward the lower end side. At the lower end side of the inner pipe, the soil in the ground and the heat medium exchange heat, and the heat medium is evaporated so as to have a vapor pressure balanced with the temperature in the ground. The evaporated heat medium rises again in the inner tube from the lower end side toward the upper end side. That is, the inner pipe becomes a heat pipe, and the refrigerant in the refrigerant pipe can be heated by underground heat.
International Publication No. WO2004 / 111559 Pamphlet

  However, in the conventional underground heat exchanger like this patent document 1, when a crack is generated in a pipe buried in the ground due to a natural disaster or the like, it is considered that the heat medium leaks from the cracked portion. If it becomes like this, the quantity of the heat medium in the said enclosed space will reduce, and there exists a problem that the heat exchange capability of an underground heat exchanger falls.

  The present invention has been made in view of such a point, and an object of the present invention is to provide any cause in the underground heat exchanger that exchanges heat between the heat exchange fluid and the soil in the ground via a sealed heat medium. Thus, even if the heat medium in the pipe leaks to the outside of the pipe, it is possible to minimize a decrease in heat exchange capacity.

  1st invention presupposes the underground heat exchanger provided with the outer pipe | tube (3) and the inner pipe | tube (2) inserted inside the pipe | tube of this outer pipe | tube (3).

  The outer pipe (3) of the above-mentioned underground heat exchanger is buried in the ground so that the pipe axis direction is along the vertical direction, and the end of the pipe is closed to enclose the heat medium inside the pipe. The inner pipe (2) has a fluid flow path (2a) through which the heat exchange fluid flows, and the outer pipe (3) has an inner pipe (2). It is characterized in that at least one or more partition walls that divide the sealed space (7) into a plurality of divided spaces (7a) along the tube axis direction are provided.

  In the first invention, the sealed space (7) is partitioned into a plurality of divided spaces (7a). In this way, even if a crack occurs in the outer pipe (3) due to a natural disaster, the heat medium only leaks into the ground from the divided space (7a) corresponding to the cracked part, and heat is generated from the other divided space (7a). The medium can be prevented from leaking into the ground.

  According to a second aspect of the present invention, in the first aspect, the outer tube (3) and the inner tube (2) include an inner peripheral surface (3a) of the outer tube (3) and an outer peripheral surface of the inner tube (2) ( 2b) are arranged so as to be substantially in contact with each other.

  Here, after the underground heat exchanger of the present invention is buried in the ground, a heat exchange fluid having a temperature lower than that of the soil in the ground is passed through the fluid flow path (2a) of the inner pipe (2). The heat medium sealed in the outer pipe (3) releases heat to the heat exchange fluid having a temperature lower than that of the heat medium via the outer peripheral surface (2b) of the inner pipe (2). Condensate. At this time, the heat exchange fluid is heated by absorbing the heat of condensation of the heat medium.

  The heat medium condensed and liquefied on the outer peripheral surface (2b) of the inner pipe (2) passes through the inner peripheral surface (3a) of the outer pipe (3) in the ground where the temperature is higher than that of the heat medium. It absorbs heat from the soil and evaporates. The heat medium evaporated and vaporized on the inner peripheral surface (3a) of the outer tube (3) is condensed again on the outer peripheral surface (2b) of the inner tube (2). Thus, when the heat medium repeats condensation and evaporation, the heat of the soil in the ground is transmitted to the heat exchange fluid via the heat medium, and the heat exchange fluid is heated.

  On the other hand, if a heat exchange fluid having a temperature higher than that of the soil in the ground flows through the fluid flow path (2a) of the inner pipe (2), the heat medium is transferred to the inner circumference of the outer pipe (3). It condenses on the surface (3a) and evaporates on the outer peripheral surface (2b) of the inner pipe (2). Thereby, the heat of the heat exchange fluid is transmitted to the soil in the ground via the heat medium, and the heat exchange fluid is cooled.

  In the second invention, the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2) are substantially brought into contact with each other, via this contact portion, The heat medium condensed and liquefied on one surface of the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2) flows to the other surface. Here, the substantially contacted state is a state in which the outer tube (3) and the inner tube (2) are in direct contact with each other indirectly through a liquefied heat medium. And the state which is doing.

  According to a third invention, in the second invention, a circumferential groove along the circumferential direction is formed on the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2). (30, 31) is formed.

  In the third invention, the heat medium condensed and liquefied on one surface of the outer tube (3) and the inner tube (2) is formed in the circumferential groove (30, 31) formed on the one surface. It flows in the circumferential direction along the circumferential groove (30) while being held. This heat medium flows to the other surface through the contact portion of the outer tube (3) and the inner tube (2). The heat medium that has flowed to the other surface flows and evaporates along the circumferential groove (30) while being held in the circumferential grooves (30, 31) formed on the other surface. become. The circumferential groove (30) may be formed in a spiral shape.

  A fourth invention is the heat medium liquefied on one surface of the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2) in the second or third invention. Is provided with a liquid transport member (8) for transporting the liquid to the other surface.

  In the fourth invention, the heat medium liquefied on one surface of the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2) by the liquid transport member (8). Can be actively conveyed to the other surface and evaporated.

  In a fifth aspect based on the fourth aspect, the liquid conveying member (8) is a wick, and the wick includes an inner peripheral surface (3a) of the outer tube (3) and an outer periphery of the inner tube (2). It is provided so that it may contact both of surfaces (2b). Here, the wick is a porous body having a large number of fine pores formed therein, and a capillary passage is formed by the continuous fine pores. And a liquid flows through this capillary channel by capillary action. The porous body may be formed by sintering metal or ceramic powder, or may be formed by overlapping mesh-like metals or bundling metal fibers.

  In a fifth aspect of the present invention, the liquid transport member (8) is formed of a wick so that the liquefied heat medium condensed on one surface of the outer pipe (3) and the inner pipe (2) Capillary action enables positive transport to the other surface and evaporation.

  A sixth invention is characterized in that, in any one of the first to fifth inventions, the heat medium enclosed in the sealed space (7) of the outer tube (3) is carbon dioxide.

  In the sixth invention, even if a crack occurs in the outer tube (3) for some reason and the heat medium leaks from the cracked part into the ground, the heat medium is composed of carbon dioxide. It can prevent soil and groundwater from being contaminated.

  According to a seventh invention, in any one of the first to fifth inventions, the heat medium sealed in the sealed space (7) of the outer tube (3) is water.

  In the seventh invention, even if a crack occurs in the outer pipe (3) for some reason and the heat medium leaks into the ground from the cracked portion, the soil and groundwater in the ground are removed as in the fifth invention. It can prevent contamination. Moreover, since water has a larger latent heat than carbon dioxide, the amount of water sealed in the outer tube (3) can be reduced.

  The eighth invention is characterized in that, in any one of the first to fifth inventions, the heat medium enclosed in the sealed space (7) of the outer pipe (3) is ammonia.

  In the eighth invention, it is possible to reduce the thickness of the outer cylindrical portion (3) by utilizing the fact that the working pressure range of ammonia is lower than that of carbon dioxide. Moreover, since ammonia has a larger latent heat of vaporization than carbon dioxide, the amount of ammonia enclosed in the outer tube (3) can be reduced similarly to water.

  A ninth invention is a refrigerant circuit in which a compressor (10), a heat source side heat exchanger (1), an expansion mechanism (12), and a use side heat exchanger (11) are connected to perform a vapor compression refrigeration cycle. It assumes an air conditioning system with (9).

  In the air conditioning system, the inner pipe (2) of the underground heat exchanger described in any one of the first to eighth inventions is connected to the refrigerant circuit (9), and the underground heat exchange is performed. The apparatus constitutes the heat source side heat exchanger (1).

  In the ninth aspect of the invention, in the air conditioning system, a ground heat exchanger can be used as the heat source side heat exchanger (1) in the vapor compression refrigeration cycle. When the air conditioning system is a heating device, the underground heat exchanger serves as an evaporator, and the use side heat exchanger (11) serves as a condenser. In this underground heat exchanger, the low-pressure refrigerant that has flowed out of the expansion mechanism (12) exchanges heat with the soil in the ground, and the low-pressure refrigerant absorbs heat from the soil in the ground. Can be evaporated.

  On the other hand, when the air conditioning system is a cooling device, the underground heat exchanger serves as a condenser, and the use side heat exchanger (11) serves as an evaporator. In this underground heat exchanger, the high-pressure refrigerant discharged from the compressor (10) exchanges heat with the soil in the ground, and the high-pressure refrigerant dissipates heat to the soil in the ground, thereby the high-pressure refrigerant. Can be condensed.

  According to the present invention, even if a crack occurs in the outer pipe (3) due to a natural disaster or the like, only the heat medium leaks into the ground from the divided space (7a) corresponding to the cracked portion, and other divided spaces (7a ) Can be prevented from leaking into the ground. In other words, compared to the case where the sealed space (7) is not partitioned, the amount of the heat medium leaking outside from the outer tube (3) can be reduced. This causes the underground heat exchanger to be damaged for some reason. However, it is possible to minimize a decrease in the heat exchange capacity of the underground heat exchanger.

  According to the second aspect of the invention, the outer pipe (3) and the inner pipe (2) are brought into contact with each other, whereby the inner peripheral surface (3a) of the outer pipe (3) and the inner pipe (2 ), The heat medium condensed and liquefied on one surface of the outer peripheral surface (2b) can be reliably guided to the other surface and evaporated on the other surface. Thereby, the heat exchange capability of the underground heat exchanger can be improved.

  According to the third invention, the heat medium condensed and liquefied on one surface of the outer tube (3) and the inner tube (2) is a circumferential groove ( 30, 31) is guided to the other surface while being held so as not to fall downward, and is held by the circumferential groove (30, 31) formed on the other side so that it does not fall downward. Evaporates while spreading.

  In this way, the liquefied heat medium can be guided from one surface to the other surface while holding the liquefied heat medium so as not to fall downward in the circumferential groove (30, 31), and the circumferential groove Compared with the case where (30, 31) is not provided, a larger amount of the heat medium is guided to the other surface. Thereby, the heat exchange capability of the underground heat exchanger can be further improved.

  According to the fourth aspect of the present invention, the heat transfer medium condensed and liquefied on one surface of the outer tube (3) and the inner tube (2) using the liquid conveying member (8) Can be positively transported to the surface. Thereby, the heat exchange efficiency of the said underground heat exchanger can be improved further.

  Further, according to the fifth aspect, by using a wick as the liquid transport member (8), the heat medium can be transported while reducing the cost of the liquid transport member (8). It is possible to achieve both high efficiency and low cost of the underground heat exchanger.

  Further, according to the sixth and seventh inventions, even if a crack occurs in the outer pipe (3) for some reason and the heat medium leaks into the ground from the cracked part, the heat medium is carbon dioxide. So it will not contaminate the soil and groundwater in the ground. Therefore, it is possible to provide an underground heat exchanger that takes into consideration the global environment.

  Moreover, according to the said 8th invention, compared with the case where a carbon dioxide is used by using ammonia as a heat medium, the heat exchange amount of the heat medium with respect to a to-be-heated fluid and underground soil can be increased. it can. Thereby, the heat exchange capability of the underground heat exchanger can be improved.

  According to the ninth aspect of the invention, in the air conditioning system, the outer pipe (3) of the underground heat exchanger is cracked, and the heat medium in the outer pipe (3) leaks into the ground. Even if it is a case, the fall of the heat exchange capability of an underground heat exchanger can be suppressed to the minimum. Further, even when the inner pipe (2) is damaged and the heat exchange fluid flowing through the inner pipe (2) leaks, the inner pipe (2) is confined in the divided space (7a) of the outer pipe (3). Moreover, the air conditioning operation can be continued when the amount of leak is small. Therefore, it is possible to minimize the deterioration of the air conditioning system and to operate without stopping.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The heating device according to the present embodiment heats the room using underground heat and constitutes the air conditioning system of the present invention. The said heating apparatus is provided with the refrigerant circuit (9), as shown in FIG. The refrigerant circuit (9) includes a compressor (10), an indoor heat exchanger (use side heat exchanger) (11), an expansion valve (expansion mechanism) (12), and an underground heat exchanger (heat source side heat exchanger). ) And (1) are connected by refrigerant piping. Here, the underground heat exchanger (1) is buried in the ground, and the indoor heat exchanger (11) is installed indoors.

  The refrigerant circuit (9) contains a refrigerant (heat exchange fluid). As this refrigerant circulates in the refrigerant circuit (9), the underground heat exchanger (1) becomes an evaporator, the indoor heat exchanger (11) becomes a condenser, and a vapor compression refrigeration cycle is established. Configured to do.

  The compressor (10) is a hermetically sealed type, and has a variable capacity by an inverter (not shown) electrically connected to the compressor (10). The compressor (10) is configured to compress the sucked refrigerant to a predetermined pressure and discharge it.

  Although not shown in the drawings, the indoor heat exchanger (11) is a cross-fin type fin-and-and-tube in which heat transfer tubes are arranged in a plurality of paths and a number of aluminum fins are arranged orthogonal to the heat transfer tubes.・ It consists of a tube heat exchanger. An indoor fan (13) is installed in the vicinity of the indoor heat exchanger (11). Then, the refrigerant flows inside the heat transfer tube, the indoor air sent from the indoor fan (13) flows between the aluminum fins outside the heat transfer tube, and both perform heat exchange. ing.

  The expansion valve (12) is an electronic expansion valve having a variable opening. The degree of decompression of the refrigerant flowing through the expansion valve (12) is adjusted by changing the opening degree of the expansion valve (12).

  As shown in FIG. 1, the underground heat exchanger (1) has an outer pipe (3) and an inner pipe (2), and the inner pipe (2) is arranged inside the outer pipe (3). Constitutes a double-pipe heat exchanger into which is inserted. The underground heat exchanger (1) is buried in the ground so that the tube axis direction of the outer tube (3) is along the vertical direction.

  The outer pipe (3) has an upper closing plate (4) at its upper end and a lower closing plate (5) at its lower end, respectively. The outer pipe (3) has a sealed space (7 ) Is formed. In addition, a plurality of partition walls (6) are provided inside the tube at predetermined intervals in the tube axis direction. By these partition walls (6), the sealed space (7) is partitioned into a plurality of divided spaces (7a). A predetermined amount of carbon dioxide (heat medium) is sealed in each of the divided spaces (7a). In addition, since the temperature when the refrigerant of the refrigerant circuit (9) flows into the underground heat exchanger (1) is approximately between -10 ° C and 40 ° C, carbon dioxide is reduced from -10 ° C to 40 ° C. It is enclosed so as to change phase between degrees Celsius.

  Further, as shown in FIG. 2, a plurality of circumferential grooves (30) are formed along the circumferential direction on the inner wall surface (inner circumferential surface) (3a) of the outer tube (3).

  The inner pipe (2) is a U-shaped pipe. The inner pipe (2) is inserted so that its two straight pipe parts penetrate the upper closing plate (4) and the plurality of partition walls (6), and its pipe end part projects from the sealed space (7). Yes. The inner pipe (2) is fixed to the outer pipe (3) so that the outer wall surface (2b) is in contact with the inner wall surface (3a) of the outer pipe (3). A large number of circumferential grooves (31) of about 100 microns are formed on the outer wall surface (2b) of the inner tube (2). The shape of the circumferential groove (31) is merely an example.

  One of the pipe end portions of the inner pipe (2) is connected to a refrigerant pipe extending from the discharge side of the compressor (10), and the other is connected to a refrigerant pipe extending from the inlet side of the expansion valve (12). . By being connected in this way, a refrigerant passage (fluid flow path) (2a) through which the refrigerant of the refrigerant circuit (9) flows is formed inside the inner pipe (2).

-Driving action-
Next, operation | movement of the said heating apparatus is demonstrated.

  The high-pressure refrigerant discharged after being compressed to a predetermined pressure by the compressor (10) flows into the indoor heat exchanger (11). In the indoor heat exchanger (11), the high-pressure refrigerant releases heat from the indoor air sent from the indoor fan (13) and condenses, and then flows out from the indoor heat exchanger (11). On the other hand, the indoor air is warmed by this condensation heat. As a result, the room is heated. The high-pressure refrigerant that has flowed out of the indoor heat exchanger (11) flows into the expansion valve (12). In the expansion valve (12), after the high-pressure refrigerant is depressurized to a predetermined pressure to become a low-pressure refrigerant, the expansion valve (12) flows out. At this time, the low-pressure refrigerant is decompressed by the expansion valve (12) so that the saturation temperature of the decompressed low-pressure refrigerant is lower than the temperature of the soil in the ground.

  The low-pressure refrigerant that has flowed out of the expansion valve (12) flows into the underground heat exchanger (1). In the underground heat exchanger (1), the low-pressure refrigerant absorbs the underground heat and evaporates, and then flows out of the underground heat exchanger (1). The low-pressure refrigerant that has flowed out of the underground heat exchanger (1) is sucked into the compressor (10), compressed to a predetermined pressure, and then flows into the indoor heat exchanger (11) again. In this way, the refrigerant circulates in the refrigerant circuit (9), thereby heating the room.

  Next, the operation of the underground heat exchanger (1) will be described.

  The low-pressure refrigerant that has flowed out of the expansion valve (12) flows into the inner pipe (2) of the underground heat exchanger (1). When the low-pressure refrigerant having a temperature lower than the temperature of the soil in the ground flows into the inner pipe (2), the saturation temperature of carbon dioxide in each divided space (7a) is between the soil and the low-pressure refrigerant. It shall be temperature.

  In this case, as shown in FIG. 3, the carbon dioxide enclosed in each divided space (7a) of the outer pipe (3) is outside the inner pipe (2) having a temperature lower than the saturation temperature of the carbon dioxide. Condenses on the wall (outer surface) (2b). The refrigerant of the refrigerant circuit (9) absorbs the heat of condensation of carbon dioxide and evaporates. The evaporated refrigerant flows out of the underground heat exchanger (1) and is then sucked into the compressor (10).

  The carbon dioxide condensed and liquefied on the outer wall surface (2b) is held along the circumferential groove (31) by the circumferential groove (31) of the outer wall surface (2b) without falling down. It flows to spread in the circumferential direction. And this liquefied carbon dioxide is guide | induced to the inner wall face (3a) of the said outer tube | pipe (3) through the contact part of the said outer tube | pipe (3) and the said inner tube | pipe (2). The carbon dioxide introduced to the inner wall surface (3a) of the outer pipe (3) is held by the circumferential groove (30) of the outer pipe (3) without falling down, and along the circumferential groove (30). It flows to spread in the circumferential direction. Carbon dioxide evaporates on the inner wall surface (3a). The carbon dioxide evaporated and gasified on the inner wall surface (3a) moves toward the outer wall surface (2b) of the inner pipe (2) due to the density difference of carbon dioxide in the divided space (7a). It condenses again on its outer wall (2b). By repeating the phase change of carbon dioxide in this way, the ground soil outside the outer pipe (3) and the refrigerant flowing inside the inner pipe (2) exchange heat through the carbon dioxide. To do.

-Effect of the embodiment-
According to this embodiment, the sealed space (7) is partitioned into a plurality of divided spaces (7a). In this way, even if a crack occurs in the outer pipe (3) due to a natural disaster, the heat medium only leaks into the ground from the divided space (7a) corresponding to the cracked part, and heat is generated from the other divided space (7a). The medium can be prevented from leaking into the ground. That is, the amount of carbon dioxide leaking outside from the outer tube (3) can be reduced as compared with the case where the sealed space (7) is not partitioned.

  Since the amount of carbon dioxide leaking outside the outer pipe (3) can be reduced in this way, even if the heat medium leaks outside the outer pipe (3), the underground heat exchanger A decrease in heat exchange capacity can be minimized.

  Further, according to the present embodiment, carbon dioxide condensed and liquefied on the outer wall surface (2b) of the inner pipe (2) by bringing the outer pipe (3) and the inner pipe (2) into contact with each other. It can be reliably guided to the inner wall surface (3a) of the outer pipe (3). In addition, circumferential grooves (30, 31) are formed on the inner wall surface (3a) of the outer tube (3) and the outer wall surface (2b) of the inner tube (2), respectively. It is possible to guide and evaporate more to the inner wall surface (3a) of the outer pipe (3) while holding the circumferential groove (30, 31) so as not to fall downward. Thereby, the heat exchange capability of the underground heat exchanger (1) can be improved.

  Further, according to the present embodiment, even if a crack occurs in the outer tube (3) for some reason and the heat medium leaks into the ground from the cracked part, the heat medium is carbon dioxide, so There is no contamination. Furthermore, even if the inner pipe (2) is damaged and the heat exchange fluid flowing through it is leaked, it will be trapped in the divided space (7a), and soil and groundwater due to leakage into the ground Contamination can be avoided and the air conditioning operation can be continued when the amount of leakage is small. Therefore, the underground heat exchanger (1) in consideration of the global environment can be provided.

  Moreover, according to this embodiment, the heat transfer performance of the inner pipe (2) can be improved by forming a large number of fine grooves on the outer wall surface (2b) of the inner pipe (2). The heat exchange capacity of the underground heat exchanger can be improved.

-Modification of the embodiment-
In the above embodiment, by providing circumferential grooves (30, 31) in the outer tube (3) and the inner tube (2), carbon dioxide liquefied on the outer wall surface (2b) of the inner tube (2) is obtained. Although the heat exchange capacity of the underground heat exchanger was improved by guiding more to the inner wall surface (3a) of the outer pipe (3), in the modified example, instead of the circumferential groove (30, 31) The wick (8) is provided.

  The underground heat exchanger (1) provided with the wick (8) is shown in FIGS. 4 and 5, and an enlarged view of FIG. 5 is shown in FIG. The internal details of the underground heat exchanger (1) are shown in FIG. The wick (8) is provided so as to contact both the inner wall surface (3a) of the outer tube (3) and the outer wall surface (2b) of the inner tube (2). Then, using the capillary phenomenon of the wick (8), the liquefied heat medium condensed on the outer wall surface (2b) of the outer tube (3) is compared with the circumferential groove (30, 31). It can be more actively conveyed to the inner wall surface (3a) of the outer tube (3) and evaporated. Thereby, the heat exchange efficiency of the underground heat exchanger (1) can be further improved. In addition, the heat exchange efficiency of the underground heat exchanger (1) can be increased with a relatively simple configuration in which the wick (8) is simply attached to the inner wall surface (3a) of the outer tube (3).

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

  In the present embodiment, the air conditioning system is configured by a heating device, but is not limited thereto, and the air conditioning system may be configured by a cooling device.

  In this case, the underground heat exchanger (1) constitutes a condenser, the indoor heat exchanger (11) constitutes an evaporator, and the underground heat exchanger (1) A refrigerant having a higher temperature flows in. Thereby, the outer wall surface (2b) of the inner pipe (2) forms an evaporation surface, and the inner wall surface (3a) of the outer tube (3) forms a condensation surface.

  Further, in the underground heat exchanger (1), the circumferential groove (30, 31) and the wick (8) may be used in combination.

  In the above embodiment, the liquid conveying member is formed of a wick. However, the liquid conveying member is not limited thereto, and may be, for example, a metal porous body, a porous ceramic, a fiber assembly, or a capillary tube. A member using the phenomenon may be used.

  Moreover, in the said embodiment, although carbon dioxide was used as a heat medium, it is not limited to this, For example, ammonia may be sufficient. In this way, since the operating pressure range of ammonia is lower than that of carbon dioxide, it is possible to reduce the thickness of the outer cylinder part (3). The heat medium may be water. Since water has a larger latent heat than carbon dioxide, the amount of refrigerant sealed in the outer tube (3) can be reduced. Further, in this embodiment, the heat medium is enclosed so as to change phase between −10 ° C. and 40 ° C., but this is merely an example, and the heat medium is enclosed so as to change outside the temperature range. Also good.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a ground heat exchanger for exchanging heat between a heat exchange fluid and soil in the ground, and an air conditioning system using the ground heat exchanger.

It is a longitudinal cross-sectional view of the underground heat exchanger which concerns on embodiment of this invention. It is a detailed view of the interior of the underground heat exchanger according to the embodiment of the present invention. It is an enlarged view in operation | movement of the underground heat exchanger which concerns on embodiment of this invention. It is a longitudinal cross-sectional view of the underground heat exchanger which concerns on the modification of embodiment of this invention. It is a longitudinal cross-sectional view of the underground heat exchanger which concerns on the modification of embodiment of this invention. FIG. 6 is an enlarged view of FIG. 5. It is detail drawing inside the underground heat exchanger which concerns on the modification of embodiment of this invention. It is a refrigerant circuit figure of the heating device concerning the embodiment of the present invention.

Explanation of symbols

1 Ground heat exchanger
2 Inner pipe
2a Refrigerant channel (fluid channel)
2b Outer wall surface (outer peripheral surface)
3 Outer pipe
3a Inner wall surface (inner peripheral surface)
6 Bulkhead
7 Sealed space
7a Partition space
8 Wick (Liquid conveying member)
9 Refrigerant circuit

Claims (9)

An underground heat exchanger comprising an outer pipe (3) and an inner pipe (2) inserted inside the outer pipe (3),
The outer pipe (3) is buried in the ground so that the pipe axis direction is along the vertical direction, and the sealed end (7) is formed in which the end of the pipe is closed to enclose the heat medium inside the pipe. And
The inner pipe (2) has a fluid flow path (2a) through which the heat exchange fluid flows inside the pipe,
At least one partition wall (6) that divides the sealed space (7) into a plurality of divided spaces (7a) along the tube axis direction is provided on the inner side of the outer tube (3). An underground heat exchanger characterized by In claim 1,
The outer pipe (3) and the inner pipe (2) are arranged so that the inner peripheral surface (3a) of the outer pipe (3) and the outer peripheral surface (2b) of the inner pipe (2) are substantially in contact with each other. An underground heat exchanger characterized by being arranged. In claim 2,
Circumferential grooves (30, 31) are formed along the circumferential direction on the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2). A featured underground heat exchanger. In claim 2 or 3,
A liquid transport member (8) for transporting the heat medium liquefied on one surface of the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2) to the other surface is provided. An underground heat exchanger characterized by In claim 4,
The liquid conveying member (8) is a wick, and the wick is provided so as to contact both the inner peripheral surface (3a) of the outer tube (3) and the outer peripheral surface (2b) of the inner tube (2). An underground heat exchanger characterized by In any one of claims 1 to 5,
A ground heat exchanger, wherein the heat medium enclosed in the sealed space (7) of the outer pipe (3) is carbon dioxide. In any one of claims 1 to 5,
An underground heat exchanger, wherein the heat medium enclosed in the sealed space (7) of the outer tube (3) is water. In any one of claims 1 to 5,
A ground heat exchanger characterized in that the heat medium enclosed in the sealed space (7) of the outer pipe (3) is ammonia. The compressor (10), the heat source side heat exchanger (1), the expansion mechanism (12), and the use side heat exchanger (11) are connected to each other, and a refrigerant circuit (9) for performing a vapor compression refrigeration cycle is provided. An air conditioning system,
An inner pipe (2) of the underground heat exchanger according to any one of claims 1 to 8 is connected to the refrigerant circuit (9), and the underground heat exchanger is connected to the heat source side heat exchanger ( An air conditioning system characterized by comprising 1).

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