JP4594956B2 - Underground heat exchanger buried structure - Google Patents

Description

The present invention relates to a buried structure of a ground heat exchanger that is buried in the ground and exchanges heat with the ground.

In the deep part of the ground, the temperature is almost constant throughout the year (for example, 15 ° C.), and it has the property that it is colder in summer and warmer in winter than the outside air. An underground heat exchanger embedded in the ground is known to collect heat from the ground using this property or to dissipate heat to the ground. The underground heat exchanger is connected to a load device such as a heat pump, an air conditioner, or a snow melting device, and a heat medium such as air, water, or antifreeze is circulated between the load devices. The earth heat is used by being taken out.
As a conventional underground heat exchanger, as shown in (Patent Document 1), a “U-shaped tube type in which lower end portions of parallel straight pipe portions communicate with each other”, as shown in (Patent Document 2), “longitudinal direction”. There is known a "through-hole built-in type" in which lower end portions of a plurality of through-holes extending in the same direction are communicated.
Also, unlike the highly rigid underground heat exchanger disclosed in (Patent Document 1) and (Patent Document 2), as shown in (Patent Document 3), it is formed of a metal pipe with a good thermal conductor and driven into the ground. Also known is a flexible underground heat exchanger in the form of a coil spring that is arranged in a borehole using a hollow foundation pile and exchanges heat between the well water stored in the foundation pile and the heat medium. .
Japanese Patent Laid-Open No. 11-182943 JP 2001-255081 A JP 2006-10098 A

However, the above conventional techniques have the following problems.
(1) The underground heat exchanger of the U-shaped tube type and the built-in through-hole type disclosed in (Patent Document 1) and (Patent Document 2) is a straight pipe portion for increasing the heat transfer area for heat exchange with the ground. Must be about 30-200 m long. For this reason, in order to embed the underground heat exchanger in the ground, it is necessary to drill a pit to a depth of about 30 to 200 m from the surface of the earth. Therefore, there is a problem that it requires a great excavation cost and lacks excavation workability. It was.
(2) Since the potholes for embedding the underground heat exchanger are deep, a large amount of filler is required to refill the potholes, and further, there is a problem that the backfill workability is lacking.
(3) Since the technology disclosed in (Patent Document 3) is to dispose a ground heat exchanger in a borehole using a hollow foundation pile driven into the ground, after the ground heat exchanger is disposed Since it is not necessary to refill the pothole with the filler, the coil spring shape of the underground heat exchanger can be maintained. However, when the underground heat exchanger is disposed in the hole formed in the ground by boring or the like and backfilled with the filler, the coil spring-shaped underground heat exchanger is deformed by the pressure of the filler, There was a problem that excessive stress was applied locally and pitching (holes due to local corrosion) was likely to occur, resulting in lack of durability.
(4) Moreover, since the space | interval of the coil spring of a ground heat exchanger becomes non-uniform | heterogenous and becomes narrow or wide according to the pressure of a filler, it is possible to arrange a ground heat exchanger uniformly in the ground. Since it was not able to be spotted, it had the subject that heat exchange efficiency fell.
(5) In addition, when an underground heat exchanger is installed in the cavity inside the foundation pile, the heat transfer enhancement effect by groundwater flowing in the earth only acts on the outer surface of the foundation pile. Since the amount of heat transfer is limited to the contact area between the foundation pile and the ground and is almost independent of the surface area of the underground heat exchanger, there is a problem that it is difficult to increase the heat exchange amount of the underground heat exchanger. It was.

The present invention solves the above-described conventional problems, and the length is shortened to about 1/3 to 1/20 in order to obtain a heat transfer area equivalent to a ground heat exchanger having a long straight pipe portion. Therefore, the depth of the buried hole and the length of the excavation groove, etc. can be reduced to about 1/3 to 1/20 of the conventional, and the excavation cost can be greatly reduced. Excellent workability and workability, and can fill back potholes and excavation grooves with a small amount of filler material, providing excellent backfilling workability and without deformation due to the pressure of the filler when backfilled It has excellent durability because it is difficult to cause excessive stress locally and it is difficult to cause pitching. Further, the heat medium flow path can be evenly arranged in the ground, and heat exchange spots are hardly generated, and high heat exchange efficiency can be maintained. using a medium heat exchanger, the drilling portion, such as wells or excavation And Hama been filler, and an object thereof is to provide a buried structure of the underground heat exchanger a large amount of heat exchange is obtained by heat transfer promoting effect by the groundwater flowing in the earth.

In order to solve the above conventional problems, the underground heat exchanger embedding structure of the present invention has the following configuration.
The buried structure of the underground heat exchanger according to claim 1 of the present invention includes: (a) an excavation portion formed on the ground; and (b) at least part of which is formed in a spiral shape and arranged in a plurality of rows. A spiral channel through which the heat medium flows, and a spiral axis of the spiral channel in a spiral axis space whose lower end is connected to the lower end of the spiral channel and surrounded by the channel of the spiral channel A ground heat medium flow path disposed substantially in parallel and having an upper end connected by a header, and an interval holding member for maintaining a space between the spiral flow paths, and the underground heat disposed in the excavation part And (c) a granular filler filled in the excavation part, wherein the gap maintaining member of the underground heat exchanger is formed in an annular shape, and the underground of the underground heat exchanger A base portion into which the heat medium flow path is inserted or fitted, an arm portion extended to the base portion, and the underground heat exchanger formed at an end portion of the arm portion And it has a configuration including a fitting portion in which the helical flow path is fitted.
With this configuration, the following effects can be obtained.
(1) Since the heat medium has a spiral flow path through which the heat medium flows, in order to obtain a heat transfer area equivalent to the underground heat exchanger having a long straight pipe portion, the length in the direction of the spiral axis is set. It can be shortened to about 1/3 to 1/20. Therefore, the depth of the buried hole and the length of the excavation groove, etc. can be reduced to about 1/3 to 1/20 of the conventional one, the excavation cost can be greatly reduced, and the excavation amount is small, so excavation workability is excellent. It also has excellent workability.
(2) Since the dredging hole for embedding the underground heat exchanger can be made shallow and the excavation groove etc. can be shortened, the dredging hole or excavation ditch etc. can be backfilled with a small amount of filler, and the backfilling workability is excellent. .
(3) Since the gap holding member for holding the gap between the spiral channels is provided, the spiral channel is not deformed by the pressure of the filler when being backfilled, and excessive stress acts locally. Excellent durability due to difficulty in pitching.
(4) Since the gap holding member is provided, the gap between the spiral channels is prevented from being narrowed or widened by the pressure of the filler, and the spiral channel is placed in the ground. It is possible to arrange them evenly at intervals, and heat exchange spots with the ground hardly occur, and high heat exchange efficiency can be maintained.
(5) Since the underground heat medium flow path is disposed in the spiral shaft space surrounded by the flow path of the spiral flow path, heat is collected from the ground around the spiral flow path embedded in the ground, In addition, heat can be dissipated around the embedded spiral channel, drilling a pit with an inner diameter slightly larger than the outer diameter of the spiral channel, an excavation groove slightly wider than the outer diameter of the spiral channel, etc. By disposing the underground heat medium flow path therein, heat can be efficiently exchanged between the ground and the spiral flow path.
(6) Since the underground heat medium flow path is disposed in the spiral axis space of the spiral flow path, the outer diameter of the spiral of the spiral flow path can be increased and the total length of the flow path is increased. And the heat transfer area can be increased.
(7) Since the spiral flow path of the underground heat exchanger is branched and arranged in multiple lines, the entire flow rate of the spiral flow path is maintained while the flow rate of the heat medium flowing through each spiral flow path is small. The flow rate of the flowing heat medium can be increased several times, and the amount of heat exchange per unit time between the heat medium and the ground heat can be increased.
(8) The interval holding member can appropriately select the interval and quantity so that the interval of the spiral flow path can be maintained.
(9) The base of the spacing member is disposed and fixed at an appropriate interval in the underground heat medium flow path, the underground heat medium flow path is inserted inside the spiral flow path, and a connecting member is provided at the lower end thereof. After mounting, the lower end of the spiral channel is connected to the connecting member, while the spiral channel is fitted to the fitting portion of the spacing member that is disposed and fixed in the underground heat medium channel, It is possible to drop into the excavation groove from the lower end of the medium flow path, and to dispose the underground heat medium flow path and the spiral flow path over the entire length of the excavation groove.

  Here, as the spiral flow path and the underground heat transfer medium flow path, those formed of a synthetic resin such as polypropylene, polybutene, or polyamide, or a metal such as titanium are used. Of these, a synthetic resin is preferably used. This is because it is excellent in moldability, hardly corroded, and hardly causes pitting due to residual stress.

As the spiral channel, for example, a spiral channel having a spiral outer diameter of about 10 to 20 cm and a spiral axis length of about 10 to 20 m is used. The lower end of the spiral flow path can be connected to the lower end of the underground heat medium flow path by a connecting member such as an elbow pipe.
As the underground heat medium flow path, one formed in a spiral shape, one formed in a straight tube shape, or the like can be used. When the underground heat medium flow path is also formed in a spiral shape, the pipe friction resistance of the entire underground heat exchanger is about twice that when the underground heat medium flow path is formed in a straight tube shape. Therefore, the capacity of the pump that sends the heat medium to the underground heat exchanger must be increased, and the running cost increases. Therefore, the underground heat medium flow path is preferably formed in a straight tube shape.

  The spiral flow path and the underground heat medium flow path can be elongated by connecting them at a construction site by fitting, screwing, joints or the like, for example, having a length of about 5 m.

As the spacing member, for example, a base portion disposed and fixed in the underground heat medium flow channel, an arm portion extending to the base portion, and a fitting portion formed in the arm portion and fitted with a spiral flow channel Can be used. Moreover, what was provided with the rib part integrally formed with the underground heat-medium flow path, and the fitting part which is formed in a rib part and the helical flow path is fitted can also be used. In any case, the base can be appropriately selected and used as long as the base is fixed to the underground heat medium flow path, the spiral flow path is fixed by fitting or the like at the end, and the distance between the spiral flow paths is maintained. .
In addition, as the spacing member, a support member formed in a hook shape or a frame shape is disposed outside or inside the spiral flow path, and the spiral flow path is supported using a locking tool such as a binding band. What fixes to a member and hold | maintains the space | interval of a helical flow path can also be used. In addition, as a supporting member of the spacing member, for example, one or a plurality of longitudinal members formed of a metal or synthetic resin wire or rod, and an annularly formed longitudinal member are provided with an appropriate interval. And a plurality of fixing rings joined together. In addition, as the other support member, it is also possible to use a cylindrical body formed by winding a net-like body made of metal or synthetic resin and formed in a turtle shell shape or the like.
As the excavation part, a borehole drilled toward the deep part in the ground, a drilling groove or a depression excavated in the lateral direction on the ground surface, a lateral hole excavated in the lateral direction from the dredging hole, the excavation groove, or the depression is used. . Examples of the pothole include a pothole formed by boring in the ground, and a pothole formed by burying a pile provided with screw-like fins at the tip while rotating. As the excavation groove or depression, a groove excavated with a bucket such as a hydraulic excavator is used. As the horizontal hole, one excavated by jetting high-pressure jet water from a flexible hose is used.
After the underground heat exchanger is disposed in the excavation part such as a pit, the excavation part is backfilled by filling the filler to the ground or near the ground.
As the filler, it is preferable to use a material having a good thermal conductivity. For example, concrete, mortar, earth and sand, earth, sand and the like can be used. In addition, by using granular fillers such as silicon grains such as earth and sand, earth, sand, silica sand, and waste silicon, instead of hydraulic materials such as concrete and mortar as the filler, groundwater flowing in the ground It is preferable because it penetrates between the particles of the filler filled in the excavation part and the ground water promotes heat exchange between the underground heat exchanger and the ground.
In the underground heat exchanger disposed in the pit, the heat medium passes through the forward pipe (either the spiral flow path or the underground heat transfer path) of the underground heat exchanger and is deep in the ground. It is taken out from the return pipe to the ground surface, and it is preferable to make the part of the forward pipe and the return pipe from the ground surface to a depth of about 5 m have a heat insulating structure. This is because the temperature of the earth from the surface to a depth of about 5 m varies greatly depending on the season. In particular, it is preferable that the return pipe has a heat insulating structure. This is to prevent heat loss of the heat medium that has finished heat exchange with the ground.
As the number of spiral channels, 2 to 5 are preferably used. When the number of strips is larger than 5, the spiral channels are densely packed and the intervals between the spiral channels are narrowed, and voids that cannot be filled with the filler during refilling are likely to occur, which may cause ground subsidence or the filler. It is not preferable because the contact area becomes smaller and the thermal conductivity decreases.

When the underground heat medium flow path of the underground heat exchanger has a configuration including a header portion to which each of lower ends of the plurality of spiral flow paths is connected , Since the underground heat medium flow path is provided with a header portion to which a plurality of branched spiral flow paths are connected, the underground heat transfer medium flow path can be unified. Compared with the case where a plurality of underground heat medium flow paths are arranged in the ground by connecting the heat medium flow paths one by one, the workability can be improved.

As described above, according to the buried structure of the underground heat exchanger of the present invention, the following advantageous effects can be obtained.
According to the invention of claim 1,
(1) Since the length in the direction of the spiral axis can be shortened to about 1/3 to 1/20 in order to obtain a heat transfer area equivalent to the underground heat exchanger having a long straight pipe portion, The depth of the pit and the length of the digging groove can be reduced to about 1/3 to 1/20 of the conventional digging cost, and the excavation cost is greatly reduced. An underground structure for underground heat exchangers can be provided.
(2) Since the dredging hole for embedding the underground heat exchanger can be made shallow and the excavation groove etc. can be shortened, the dredging hole or excavation ditch etc. can be backfilled with a small amount of filler, and the backfilling workability is also excellent. An underground structure for underground heat exchangers can be provided.
(3) Since the gap holding member for holding the gap between the spiral channels is provided, the spiral channel is not deformed by the pressure of the filler when being backfilled, and excessive stress acts locally. It is difficult to provide a buried structure of an underground heat exchanger with excellent durability.
(4) Since the gap holding member is provided, the gap between the spiral channels is prevented from being narrowed or widened by the pressure of the filler, and the spiral channels are evenly arranged in the ground. Therefore, it is possible to provide a buried structure of the underground heat exchanger that can hardly generate heat exchange spots and can maintain high heat exchange efficiency.
(5) Heat can be collected from the ground around the spiral channel embedded in the ground, and can be dissipated to the periphery of the embedded spiral channel. The inner diameter is slightly larger than the outer diameter of the spiral channel. By excavating a trench or a drilling groove that is slightly wider than the outer diameter of the spiral channel, and placing an underground heat transfer channel in it, heat is efficiently transferred between the ground and the spiral channel. It is possible to provide a buried structure of the underground heat exchanger with high heat exchange efficiency that can be exchanged.
(6) Since the underground heat medium flow path is disposed in the spiral axis space of the spiral flow path, the outer diameter of the spiral of the spiral flow path can be increased and the total length of the flow path is increased. It is possible to provide a buried structure of a ground heat exchanger having a large heat transfer area and high heat exchange efficiency.
(7) Since the plurality of spiral flow paths of the underground heat exchanger are arranged in multiple lines and each of the plurality of spiral flow paths is provided with a header, heat flowing through each spiral flow path is provided. The flow rate of the heat medium flowing through the entire spiral flow path can be increased several times while the flow rate of the medium is small, and the heat exchange amount per unit time between the heat medium and the earth heat can be increased. A buried structure of a ground heat exchanger with high exchange efficiency can be provided.

(8) The interval holding member can appropriately select the interval and quantity so that the interval of the spiral flow path can be maintained.
(9) The base of the spacing member is disposed and fixed at an appropriate interval in the underground heat medium flow path, the underground heat medium flow path is inserted inside the spiral flow path, and a connecting member is provided at the lower end thereof. After mounting, the lower end of the spiral channel is connected to the connecting member, while the spiral channel is fitted to the fitting portion of the spacing member that is disposed and fixed in the underground heat medium channel, It is possible to drop into the excavation groove from the lower end of the medium flow path, and to dispose the underground heat medium flow path and the spiral flow path over the entire length of the excavation groove.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
( Reference Example 1 )
Figure 1 is a perspective view of the underground heat exchanger for use in buried structure of the underground heat exchanger in Reference Example 1, FIG. 2 is a schematic diagram showing a buried structure of the underground heat exchanger in Reference Example 1.
In FIG. 1, 1 is a ground heat exchanger used for the underground heat exchanger embedment structure in Reference Example 1 of the present invention, 2 is made of a synthetic resin such as polypropylene, polybutene, and polyamide, and is made of a metal such as titanium. Spiral flow path, part of which is formed in a spiral shape and through which a heat medium such as air, water, antifreeze and the like flows, 3 is a spiral axis formed around the spiral axis inside (inside the spiral) of the spiral flow path 2 The space 4 is a connecting member made of an elbow pipe connected to the lower end of the spiral flow path 2, and 5 is made of a synthetic resin such as polypropylene, polybutene, polyamide, etc., made of stainless steel, metal such as titanium, etc. An underground heat transfer medium channel connected to the lower end of the spiral channel 2 via the connecting member 4 and disposed in the spiral axis space 3 substantially parallel to the spiral axis direction of the spiral channel 2, 6 is the underground Spacing maintained at an appropriate interval along the heat medium flow path 5 The base 7 of the space | interval holding member 6 by which the material and 7 were formed cyclically | annularly and the underground heat-medium flow path 5 was inserted or fitted, 8 is the arm part extended in the base 7, and 9 is the edge part of the arm part 8. It is the fitting part in which the spiral flow path 2 was formed.
In FIG. 2, 10 is the ground, 10a is a ground hole as an excavation part formed by boring on the ground 10 and burying a pile provided with screw-like fins at the tip, and the like, 10b is an underground heat exchanger 1 Is a filling material such as sand, earth and sand, earth, and mortar filled in the pit 10a.

An example of the construction method will be described below with respect to the buried structure of the underground heat exchanger in Reference Example 1 of the present invention configured as described above.
First, a pothole 10a (excavated portion) having a predetermined diameter (200 mm in the present Reference Example 1 ) and a depth that can be embedded leaving the tip of the underground heat exchanger 1 is formed.
A spiral flow path 2, a ground heat medium flow path 5, a connecting member 4, and a gap holding member 6 are prepared, and a base 7 of the gap holding member 6 is disposed in the ground heat medium flow path 5 at an appropriate interval. Fix it. Next, the underground heat transfer medium channel 5 is inserted inside the spiral channel 2, the connecting member 4 is attached to the lower end thereof, and then the lower end of the spiral channel 2 is connected to the connecting member 4. The helical flow path 2 is fitted to the fitting portion 9 of the spacing member 6 disposed and fixed in the underground heat medium flow path 5, and is inserted into the pit 10 a from the lower end of the underground heat medium flow path 5, The underground heat medium flow path 5 and the spiral flow path 2 are disposed over the entire length of 10a.
Finally, a filler 10b such as concrete, mortar, earth and sand, earth, sand, etc. is ground around the underground heat medium passage 5 and the spiral passage 2 of the underground heat exchanger 1 disposed in the pit 10a. Or it fills to the ground vicinity and refills the pothole 10a.

As described above, the underground heat exchanger 1 used for the underground heat exchanger embedment structure in the reference example 1 disposed in the ground includes the upper ends of the spiral flow path 2 and the underground heat transfer medium path 5. Connected to a load device (not shown) such as a heat pump, a cooling / heating device, a snow melting device, etc., and a heat medium in which cold heat and heat are exchanged by the load device flows from the upper end to the lower end of the spiral flow path 2 and between the ground 10 The heat exchange is performed, and the heat exchanged heat medium is circulated from the upper end of the underground heat medium flow path 5 to the load device.
The direction in which the heat medium flows is not limited to this, and conversely, the heat medium is introduced into the underground heat exchanger 1 from the upper end of the underground heat medium flow path 5, and the spiral flow path 2. You may make it take out from the upper end of this, and let it flow to a load apparatus. In this case, the same effect can be obtained.

As described above, since the buried structure of the underground heat exchanger in Reference Example 1 of the present invention is configured, the following operation is obtained.
(1) Since the underground heat exchanger 1 includes the spiral flow path 2 through which the heat medium flows, the heat transfer area equivalent to that of a conventional underground heat exchanger having a long straight pipe portion Therefore, the length in the spiral axis direction can be shortened to about 1/3 to 1/20. Therefore, the depth of the pothole where the underground heat exchanger 1 is disposed can be about 1/3 to 1/20 of the depth of the pothole in the case of a conventional straight tubular underground heat exchanger, The dredging cost for dredging can be greatly reduced, and the excavation work is small and the excavation workability is excellent.
(2) Since the pothole for embedding the underground heat exchanger 1 can be made shallow, the pothole can be backfilled with a small amount of filler, and the backfilling workability is excellent.
(3) Since the gap holding member 6 that holds the gap of the spiral flow path 2 is provided, the spiral flow path 2 is not deformed by the pressure of the filler when being backfilled, and is locally excessive. Since stress is hard to work and pitching is difficult to occur, durability is excellent.
(4) Since the gap holding member 6 is provided, the gap between the spiral channels 2 is prevented from being narrowed or widened by the pressure of the filler, and the spiral channel 2 is spaced from the ground. The holding members 6 can be arranged uniformly at intervals, and heat exchange spots are hardly generated, and high heat exchange efficiency can be maintained.
(5) Since the interval of the spiral channel 2 can be maintained by the interval holding member 6, the spiral channel 2 can be formed of a spiral tube made of a synthetic resin and formed in a coil shape. Remarkably excellent in properties.
(6) When the spiral flow path 2 is formed of a spiral tube made of a synthetic resin and formed in a coil shape, the spiral flow path 2 expands and contracts in the direction of the spiral axis, so it is in a contracted state when transported to the construction site. It is compact and has excellent transportability, and it can be easily installed by being fixed by the interval holding member 6 while being stretched at the construction site, and has excellent workability.

(7) The interval holding member 6 disposed and fixed in the underground heat medium passage 5 can be appropriately selected for the interval and quantity so that the interval of the spiral passage 2 can be maintained.

(8) Since the underground heat exchanger 1 having the spiral channel 2 is disposed in the pothole 10a and filled with the filler 10b, the filler 10b and the spiral channel 2 can be used even if the pothole 10a is shallow. The contact area can be increased, and the amount of heat exchange per unit depth of the hole 10a can be increased.

Here, in this reference example 1 , although the case where the spiral flow path 2 of the underground heat exchanger 1 was arrange | positioned over the full length of the pothole 10a was demonstrated, a part of pothole 10a, for example, depth In some cases, the spiral flow path 2 is disposed only at a depth of 5 m or more, and a straight tubular flow path is connected from there to the ground surface. The temperature of the earth from the ground surface to a depth of about 5m varies greatly depending on the season and is not suitable for heat exchange with the heat medium (in winter, the temperature of the earth 10 near the surface decreases, so the heat medium radiates heat to the earth 10) In summer, the temperature of the ground 10 near the surface rises, so the heat medium collects heat from the ground 10.) To reduce the heat loss by shortening the time for the heat medium to pass through the ground 10 near the surface. It is.
For the same reason, a heat insulating material such as glass wool may be disposed on the outer surface of the channel near the ground surface of the underground heat exchanger 1. In some cases, a heat insulating material such as pumice or foamed glass is used only near the ground surface as the filler 10b to be filled in the pothole 10a. Thereby, heat exchange between the heat medium and the ground 10 near the ground surface can be suppressed and heat loss can be reduced.

Moreover, in the buried structure of the underground heat exchanger according to the first reference example , the case where the underground heat exchanger 1 is disposed in the pothole 10a as the excavating portion has been described. However, instead of the pothole 10a, a hydraulic excavator is used. In some cases, a digging groove as a digging portion is formed on the ground surface by digging with a bucket such as. In this case, first, a excavation groove in which the underground heat exchanger 1 can be disposed is formed. The depth, width, and length of the excavation groove are determined in consideration of the outer diameter and length of the spiral channel 2 of the underground heat exchanger 1. Next, the spiral flow path 2, the underground heat medium flow path 5, the connecting member 4, and the interval holding member 6 are prepared, and the base portion 7 of the interval holding member 6 is provided at an appropriate interval in the underground heat medium flow path 5. To fix. Next, the underground heat transfer medium channel 5 is inserted inside the spiral channel 2, the connecting member 4 is attached to the lower end thereof, and then the lower end of the spiral channel 2 is connected to the connecting member 4. While the helical flow path 2 is fitted to the fitting portion 9 of the spacing member 6 disposed and fixed in the underground heat medium flow path 5, it is dropped into the excavation groove from the lower end of the underground heat medium flow path 5, and the excavation groove The underground heat medium flow path 5 and the spiral flow path 2 are disposed over the entire length. Finally, fillers such as concrete, mortar, earth and sand, earth, and sand are filled around the underground heat medium passage 5 and the spiral passage 2 of the underground heat exchanger 1 disposed in the excavation groove. Backfill the excavation groove.
With this configuration, there is an effect that the excavation cost can be reduced as compared with the case where the underground heat exchanger is disposed in the pothole.
In addition, although the case where the underground heat-medium flow path 5 was formed in the straight tube shape was demonstrated, the underground heat medium is connected by connecting several straight-tube underground heat-medium flow paths using an elbow pipe etc. The flow path 5 may be formed in a curved shape, a U shape, or the like, and the overall length of the underground heat exchanger may be reduced. In this case, the underground heat exchanger can be embedded by using a recess having a wider excavation groove as an excavation part. Thereby, even when a long excavation groove cannot be formed due to the site or topography, the underground heat exchanger can be embedded and the flexibility is excellent.

( Reference Example 2 )
3A is a side view of the underground heat exchanger used in the underground heat exchanger embedded structure in Reference Example 2 , and FIG. 3B is the embedded structure of the underground heat exchanger in Reference Example 2 . It is a cross-sectional view of the underground heat exchanger to be used.
In the figure, 11 is a geothermal heat exchanger used for the underground heat exchanger embedding structure in Reference Example 2 of the present invention, 12 is a pipe member made of a synthetic resin such as polypropylene, polybutene, and polyamide, and 12a is a pipe. The spiral flow path is formed integrally with the member 12 and has a substantially square cross section on the outer peripheral surface of the pipe member 12. In the present reference example 2 , since the spiral flow path 12a is formed integrally with the pipe member 12, the distance between the spiral flow paths 12a is maintained, so that the pipe member 12 functions as a distance maintaining member. . Reference numeral 13 denotes a spiral shaft space in the pipe member 12 formed around the spiral shaft inside the spiral flow path 12a. Reference numeral 14 denotes a lower end of the underground heat medium flow path 15 which is attached to the lower end of the pipe member 12 and will be described later. A lid-like connecting member formed with a connecting channel 14a that connects the lower end of the spiral channel 12a, 14b is a fitting portion formed inside the connecting member 14, 15 is a polypropylene, polybutene, polyamide, or the like It is made of a synthetic resin, a metal such as titanium, and the like, and the lower part is fitted to the fitting portion 14b and connected to the connecting channel 14a. The spiral shaft space 13 is substantially parallel to the spiral axis direction of the spiral channel 12a ( This is a straight tubular underground heat medium flow path disposed in the pipe member 12).

As described above, since the underground heat exchanger used for the underground heat exchanger embedment structure in Reference Example 2 of the present invention is configured, in addition to the actions described in Reference Example 1 , the following actions are provided. can get.
(1) Since the spiral flow path 12a is formed integrally with the pipe member 12 and the interval between the spiral flow paths 12a is maintained, the spiral flow path 12a is not deformed by the filler and has excellent durability. At the same time, the spiral flow paths 12a can be evenly arranged in the ground, and heat exchange spots hardly occur, and high heat exchange efficiency can be maintained.
(2) If the filler is not filled between the spiral flow path 12a and the underground heat medium flow path 15 when being refilled after being disposed in the pothole, the spiral flow path 12a and the underground heat medium flow The passage 15 can be insulated with air in the pipe member 12. For this reason, it is possible to collect or dissipate heat by flowing the heat medium from which cold heat or heat is extracted by the ground load device from the upper end to the lower end of the spiral flow path 12a. By flowing from the lower end of 15 toward the upper end, the heat medium can be taken out without being affected by the heat of the spiral flow path 12a or the ground, and the heat exchange efficiency can be increased.

In the second reference example , the case where the cross section of the spiral flow path 12a is formed in a substantially rectangular shape has been described. However, the present invention is not limited to this, and a circular shape, a semicircular shape, or the like can be appropriately selected. In these cases, the same effect can be obtained. In order to reduce filling spots of the filler, it is desirable to round the outer shape of the spiral flow path 12a without making it angular.

( Embodiment 1 )
Figure 4 is a perspective view of the underground heat exchanger for use in buried structure of the underground heat exchanger of the first embodiment.
In the figure, 21 is a ground heat exchanger used in the underground heat exchanger embedment structure in Embodiment 1 of the present invention, 22 and 22 are made of synthetic resin such as polypropylene, polybutene, polyamide, etc., metal such as titanium, etc. In this embodiment, at least a part is formed in a spiral shape, and a heat medium such as air, water, or antifreeze liquid flows through the inside, and in the present embodiment, two are arranged in parallel and formed in two strips. 22a is a header to which the upper ends of the spiral flow paths 22 and 22 are connected, 23 is a spiral axis space formed around the spiral axis inside the spiral flow paths 22 and 22, and 24 and 24 are spiral flows. The connecting members 25 and 25 are elbow pipes connected to the lower ends of the paths 22 and 22, and 25 and 25 are made of a synthetic resin such as polypropylene, polybutene, polyamide, etc., made of metal such as titanium, etc. An underground heat transfer medium passage 25a, which is connected to the lower ends of the helical flow paths 22 and 22 through 24 and disposed in the helical shaft space 23 substantially parallel to the spiral axis direction of the helical flow paths 22 and 22, A header to which the upper ends of the underground heat medium flow paths 25, 25 are connected, 26 is a spacing member disposed at an appropriate interval along the underground heat medium flow paths 25, 25, and 27 is underground heat. The base part of the interval holding member 26 into which the medium flow paths 25, 25 are inserted, Arm portion extending 27, 29 is a fitting portion with a helical flow path 22 is formed at the end of the arm portion 28 is fitted.

As described above, since the underground heat exchanger used in the underground heat exchanger embedding structure in Embodiment 1 of the present invention is configured, the following operation is performed in addition to the operation described in Reference Example 1. Is obtained.
(1) Since the spiral flow paths 22 and 22 are arranged in two strips and each of the spiral flow paths 22 and 22 includes the header 22a to which the upper ends of the spiral flow paths 22 and 22 are connected, each spiral flow path is provided. The flow rate of the heat medium flowing through the spiral flow paths 22 and 22 can be doubled while the flow velocity of the heat medium flowing through the heat transfer medium 22 and 22 is small, and heat exchange per unit time between the heat medium and the ground heat is performed. The amount can be increased.

In addition, in this Embodiment, although the case where two spiral flow paths were provided in parallel and formed in two strips was described, the number of strips can be appropriately selected in relation to the flow rate of the heat medium, In some cases, three or more are arranged side by side to form three or more. In these cases, the same effect can be obtained.
Moreover, although the case where the header 25a is connected to the upper ends of the underground heat medium flow paths 25, 25 has been described, the header 25a may be connected to the lower ends of the spiral flow paths 22, 22. In this case, the heat medium is gathered by the header 25a connected to the lower ends of the spiral flow paths 22 and 22, and the underground heat medium flow path is formed in the flow paths of the spiral flow paths 22 and 22 (in the spiral). One is inserted, and the lower end of the inserted underground heat medium flow path is connected to the header 25a. In this case, the same effect can be obtained.

( Reference Example 3 )
Fig.5 (a) is a perspective view of the underground heat exchanger used for the underground structure of the underground heat exchanger in the reference example 3 , FIG.5 (b) is a longitudinal cross-section of the underground heat exchanger in the AA line. FIG. In addition, the same thing as Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits description.
In the figure, 31 is a ground heat exchanger used in the underground heat exchanger embedment structure in Reference Example 3 of the present invention, and 32 is a header portion formed integrally with the lower end of a ground heat medium passage 34 to be described later. , 33 is connected to the header portion 32 and connected to the lower ends of the spiral flow paths 22 and 22, and 34 is made of a synthetic resin such as polypropylene, polybutene, polyamide, etc., and is formed in a straight tube integrally with the header portion 32. The underground heat medium flow path 34 a disposed in the spiral shaft space 23 substantially parallel to the spiral axis direction of the spiral flow paths 22, 22 has a narrowed inner diameter on the upper end side of the underground heat medium flow path 34. The restricting portion 34b is a heat insulating material such as glass wool or rock wool disposed around the restricting portion 34a, and 35 is a single piece symmetrically formed along the longitudinal direction of the underground heat medium passage 34. The ribs 36 are spaced at appropriate intervals along the longitudinal direction outside the ribs 35. Only spiral flow path 22 is formed concavely is fitted portion which is fitted.

As described above, since the underground heat exchanger used in the underground heat exchanger embedding structure in Reference Example 3 of the present invention is configured, in addition to the operations described in the first embodiment , the following operations are performed. Is obtained.
(1) Since the underground heat medium flow path 34 is integrally formed with the header portion 32 to which the two spiral flow paths 22 and 22 are connected, the two spiral flow paths 22 and 22 are underground. It is securely connected to the heat medium passage 34 and has excellent workability.
(2) Since the rib portion 35 is formed along the longitudinal direction of the underground heat medium flow path 34, the underground heat medium flow path 34 can be made robust.
(3) Since the narrowed portion 34a having a narrow inner diameter is formed on the upper end side of the underground heat medium flow path 34, the heat medium passing through the narrowed portion 34a has a high flow rate, so heat exchange with the buried ground is performed. The time to do is shortened. Moreover, the outer surface area of the throttle part 34a can be reduced, and the heat transfer area with the ground can be reduced. For this reason, if the underground heat exchanger 31 is embedded so that the constricted portion 34a is located at a depth of about 5 m from the ground surface, it is less likely to be affected by temperature fluctuations near the ground surface where the temperature changes greatly depending on the season. Can prevent heat loss.
(4) Since the heat insulating material 34b on the outer periphery of the diaphragm portion 34a of the ground heat medium flow path 34 is provided, the diaphragm portion 34a of the heat insulating material 34b is disposed at up to about 5m in depth from the ground surface If the underground heat exchanger 31 is buried so as to be located, the heat insulating property of the heat insulating material 34b makes it difficult to be affected by temperature fluctuations near the ground surface where the temperature change is large, and heat loss can be prevented.

In the reference example 3 , the case where two rib portions 35 are formed has been described, but three or more rib portions 35 may be formed. In this case, the same effect can be obtained.
Moreover, although the case where the header part 32 was formed integrally with the underground heat-medium flow path 34 was demonstrated, the header part was formed separately from the underground heat-medium flow path 34, and the underground heat-medium flow path 34 was formed. In some cases, it is fixed to the lower end of the plate by means of adhesion, welding, fitting, screwing or the like. In this case, the same effect can be obtained.
Further, the heat insulating material 34b can obtain the same effect by using a pumice-like porous ceramic or glass foam as a filler.

( Reference Example 4 )
FIG. 6 is a perspective view of the underground heat exchanger used in the buried structure of the underground heat exchanger in Reference Example 4 . In addition, the thing similar to what was demonstrated in the reference example 1 attaches | subjects the same code | symbol, and abbreviate | omits description.
In the figure, 41 is a ground heat exchanger used in the underground heat exchanger embedding structure in Reference Example 4 of the present invention, and 42 is a ground heat exchanger 41 provided with a support member 45 and a locking tool 46 described later. An interval holding member disposed on the outside, 43 is a vertical member formed of a metal or synthetic resin wire or bar, 44 is an annular shape, and is welded at an appropriate interval to the vertical member 43 by welding or the like. A plurality of fixed rings joined together, 45 is a support member formed in a frame shape by the vertical members 43 and the fixed ring 44 and disposed outside the spiral flow path 2, and 46 is a vertical member 43 of the support member 45 or fixed. A locking tool such as a binding band for fixing the spiral flow path 2 to the ring 44.

As described above, since the underground heat exchanger used for the underground heat exchanger embedment structure in Reference Example 4 of the present invention is configured, the following actions are provided in addition to the actions described in Reference Example 1. can get.
(1) Since the spacing member 42 includes a support member 45 disposed outside the spiral flow path 2 and the spiral flow path 2 is surrounded from the outside, the support member 45 forms the spiral flow path. 2 and the underground heat medium flow path 5 can be smoothly inserted into a pit or excavation groove excavated, and the insertion workability is excellent.

Here, in this reference example 4 , the case where the support member 45 formed in a frame shape by the vertical member 43 and the fixing ring 44 has been described, but it is formed in a turtle shell shape or the like made of metal or synthetic resin. In some cases, the formed net-like body is rolled and formed into a cylindrical shape as a support member. In this case, since the support member can be formed using a net-like body used for a net fence or the like, the versatility is excellent.

The present invention relates to a buried structure of a ground heat exchanger that is buried in the ground and exchanges heat with the ground, and obtains a heat transfer area equivalent to that of a ground heat exchanger having a long straight pipe portion. Therefore, since the length can be shortened to about 1/3 to 1/20, the depth of the pothole to be buried can be reduced to about 1/3 to 1/20 of the conventional depth, and the excavation cost is greatly increased. It can be reduced and the excavation amount is small, so excavation workability is excellent and workability is excellent. Also, filling holes can be backfilled with a small amount of filling material, and backfilling workability is excellent. It is not deformed by the pressure of the material, and it is difficult to apply excessive stress locally and has excellent durability. Furthermore, the flow path of the heat medium can be evenly arranged in the ground, and the high heat exchange efficiency can be maintained without causing spots. with underground heat exchanger, filler Ya filled in the drilling portion of such wells Chinai can provide buried structure of the underground heat exchanger a large heat exchange amount can be obtained by the promotion of heat transfer by groundwater flowing.

The perspective view of the underground heat exchanger used for the underground structure of the underground heat exchanger in the reference example 1 Schematic diagram of buried structure of underground heat exchanger in Reference Example 1 (A) cross-section of the underground heat exchanger for use in buried structure of the underground heat exchanger in side view (b) Reference Example 2 of the underground heat exchanger for use in buried structure of the underground heat exchanger in Reference Example 2 Figure The perspective view of the underground heat exchanger used for the underground structure of the underground heat exchanger in Embodiment 1 (A) Perspective view of the underground heat exchanger used for the buried structure of the underground heat exchanger in Reference Example 3 (b) Vertical sectional view of the underground heat exchanger at line AA The perspective view of the underground heat exchanger used for the underground structure of the underground heat exchanger in the reference example 4

1,11,21,31,41 Underground heat exchanger 2,12a, 22 Spiral flow path 3,13,23 Spiral axial space 4,14,24 Connecting member 5,15,34 Underground heat transfer path 6 , 26 Interval holding member 7, 27 Base portion 8, 28 Arm portion 9, 29, 36 Fitting portion 10 Ground 10a Groove 10b Filler 12 Pipe member (interval holding member)
14b Fitting part 22a, 25a Header 32 Header part 33 Joint part 34a Throttle part 34b Heat insulating material 35 Rib part 42 Spacing member 43 Vertical member 44 Fixing ring 45 Support member 46 Locking tool

Claims (1)

(A) excavation part formed in the ground; (b) a spiral flow path in which at least a part is formed in a spiral shape and a plurality of strips are arranged side by side and a heat medium flows through the inside; and a lower end is the spiral flow A ground heating medium flow path that is connected to the lower end of the path and surrounded by the flow path of the spiral flow path and is arranged substantially parallel to the spiral axis of the spiral flow path and has an upper end connected by a header. And an interval holding member that holds the interval between the spiral flow paths, and a ground heat exchanger disposed in the excavation part, and (c) a granular filler filled in the excavation part, The gap maintaining member of the underground heat exchanger is formed in an annular shape, and a base portion into which the underground heat medium flow path of the underground heat exchanger is inserted or fitted, and extends to the base portion. includes a set by an arm portion, a fitting portion to which the spiral flow path is formed at an end portion of the arm portion and the underground heat exchanger is fitted, the Buried structure of underground heat exchanger, wherein the door.

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