JP2014228184A - Underground installation-type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground installation-type heat exchanger which can employ such a material with proper thermal conductivity as a metal while achieving high heat exchange efficiency, which keeps a construction cost low, and which is excellent in maintainability.SOLUTION: An underground installation-type heat exchanger of the present invention is buried in the ground to perform heat exchange of a heating medium with respect to earth thermal. The underground installation-type heat exchanger includes an air circulation pipeline through which air as the heating medium is circulated, an air inlet that is opened on the side of one end of the air circulation pipeline, an air outlet that is opened on the side of the other end of the air circulation pipeline, and a spiral fin that is provided in at least a part of the inside of the air circulation pipeline.

Description

  The present invention relates to an underground heat exchanger that is buried in the ground and performs heat exchange of a heat medium for underground heat.

  In the ground more than 2m deep, the temperature is almost constant throughout the year. Utilizing this fact, underground heat exchangers that perform heat exchange of the heat medium with underground heat are used.

  In general, air is used as a heat medium, and the underground heat exchanger includes an air circulation pipe through which the air flows. The air circulation pipe is folded back in the underground deep layer. For example, the air introduced into the air circulation pipe on the ground returns to the ground again after heat exchange in the underground deep layer. It comes to come.

  In the underground heat exchanger disclosed in Japanese Patent Application Laid-Open No. 2007-10276 (Patent Document 1), the air as a heat medium sufficiently exchanges heat with the underground heat in order to increase the heat exchange efficiency. The forward part of the road (the part going down into the ground) is formed in a spiral shape with resin.

JP 2007-10276

  Spiral pipes have a longer passage time (residence time) in the pipe of air, which is a heating medium, than vertical straight pipes, and are expected to fully exchange heat with underground heat. it can.

  However, in the underground heat exchanger described in Patent Document 1, since the forward path portion needs to be formed in a spiral shape, the material is limited to a resin having good workability, and the thermal conductivity is like that of metal. Good material cannot be adopted. Moreover, since the installation area of the underground heat exchanger is large, there is also a disadvantage that the excavation area becomes large and the construction cost is high. Further, since the structure of the underground heat exchanger is complicated, the maintainability is not good.

  The present invention has been created based on the above findings. The object of the present invention is to provide a material with good thermal conductivity such as metal, while realizing high heat exchange efficiency, reducing the construction cost, and maintaining the heat in the ground. Is to provide an exchanger.

  The present invention is an underground heat exchanger that is buried in the ground and performs heat exchange of the heat medium with respect to the ground heat, the air circulation pipe through which air as the heat medium flows, and the air flow An air inlet opening at one end of the pipe, an air outlet opening at the other end of the air circulation pipe, and a helical fin provided at least in part inside the air circulation pipe; , It is an underground installation type heat exchanger characterized by including.

  According to the present invention, the air inside the air circulation pipe is not formed into a spiral shape, but the air inside the air circulation pipe is provided by providing a spiral fin at least at a part inside the air circulation pipe. By making at least a part of the flow path spiral, it is possible to lengthen the passage time (residence time) of the air in the pipeline and sufficiently exchange heat with the underground heat, that is, high heat exchange While it is possible to achieve efficiency, it is also possible to employ a material having good thermal conductivity such as metal, so that the construction cost can be suppressed and the maintainability is excellent.

  Preferably, the spiral fin is installed so as to be able to swing inside the air circulation pipe. Specifically, for example, the spiral fins can be arranged such that both side edges of the spiral fins have a gap of about 0.5 cm with respect to the inner wall of the air flow conduit. In this case, the spiral fins are oscillated by the air flow, turbulence is generated, the air flow is deteriorated, and the passage time (residence time) of the air in the pipeline is further increased, so that the underground heat It becomes possible to perform heat exchange more sufficiently.

  In the present specification, the term “spiral” is not limited to a mathematically defined smooth spiral curved surface, and should be understood as a term including a spiral staircase with a step. In other words, in the present invention, the spiral fin may have a portion that transitions into a smooth spiral curved surface and / or a portion that transitions in a spiral staircase with a step. May be.

  The spiral fin is preferably provided with a hole. Also in this case, the turbulent flow is generated, the air flow is deteriorated, the passage time (residence time) in the air pipe is further increased, and it becomes possible to further sufficiently exchange heat with the underground heat. .

  Irregularities may be provided on the surface of the spiral fin instead of or in addition to many holes. Also in this case, the turbulent flow is generated, the air flow is deteriorated, the passage time (residence time) in the air pipe is further increased, and it becomes possible to further sufficiently exchange heat with the underground heat. .

  The present invention can be applied to a so-called U-shaped underground heat exchanger, or a so-called coaxial double tube underground heat exchanger. That is, in the present invention, the air circulation pipe may have a pipe that is folded back in a substantially U shape, or is formed by a space between the inner pipe and the outer pipe arranged coaxially. You may have the pipe line of the circular section made. In the latter case, for example, the inner tube may be made of resin, the outer tube may be made of metal, and the helical fin may be disposed in the pipe having an annular cross section.

  According to the present invention, the air inside the air circulation pipe is not formed into a spiral shape, but the air inside the air circulation pipe is provided by providing a spiral fin at least at a part inside the air circulation pipe. By making at least a part of the flow path spiral, it is possible to lengthen the passage time (residence time) of the air in the pipeline and sufficiently exchange heat with the underground heat, that is, high heat exchange While it is possible to achieve efficiency, it is also possible to employ a material having good thermal conductivity such as metal, so that the construction cost can be suppressed and the maintainability is excellent.

It is the schematic of the underground installation type heat exchanger of the 1st Embodiment of this invention. It is the schematic of the underground installation type heat exchanger of the 2nd Embodiment of this invention, (a) is a top view, (b) is a sectional side view. It is the schematic of the underground installation type heat exchanger of the 3rd Embodiment of this invention, (a) is a top view, (b) is a sectional side view. It is the schematic of the underground installation type heat exchanger of the 4th Embodiment of this invention, (a) is a top view, (b) is a sectional side view.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view of a so-called U-tube type underground heat exchanger according to a first embodiment of the present invention. As shown in FIG. 1, the underground heat exchanger 10 according to the present embodiment is buried in the ground and performs heat exchange of air as a heat medium with respect to the underground heat. Yes.

  And as shown in FIG. 1, the underground installation type heat exchanger 10 of this Embodiment opens to the one end side of the air distribution pipe 11 through which the air as a heat medium distribute | circulates, and the air distribution pipe 11 An air inflow port 12 and an air outflow port 13 that opens to the other end of the air circulation pipe 11 are provided. The air circulation pipe 11 has vertical straight portions 11a and 11b, and a substantially U-shape. And a portion 11c that is folded back.

  In addition, spiral fins 15 and 16 are provided inside the vertical straight portions 11 a and 11 b of the air circulation pipe 11. In the present embodiment, the spiral fins 15 are provided over substantially the entire vertical linear portion 11a, but the spiral fins 16 are provided only in the region below the vertical linear portion 11b. And supported by the air inflow port 12 or the air outflow port 13 via support bar portions 17 and 18 extending in the upper regions of the vertical linear portions 11a and 11b, respectively.

  The spiral fins 15 and 16 of the present embodiment are formed in a smooth spiral curved surface, and both side edges thereof are 0 with respect to the inner walls of the vertical straight portions 11a and 11b of the air circulation pipe 11. It is arranged so as to leave a gap of about 5 cm. Thereby, when the air flow passes through the vertical linear portions 11a and 11b, the spiral fins 15 and 16 swing.

  The air circulation pipe 11 is constituted by a pipe having a circular cross section of φ150 (for example, made of an aluminum alloy having excellent corrosion resistance and thermal conductivity), and the length of the vertical straight portions 11a and 11b is about 5 m. The length of the portion where the spiral fins 16 are provided is about 3 m (to exchange heat at a position deeper than 2 m in the ground), and the radius of curvature of the portion 11 c folded back in a substantially U shape is about 50 cm. The spiral fins 15 and 16 are also made of metal (for example, made of an aluminum alloy having excellent corrosion resistance and thermal conductivity).

  In addition, an air duct 19 is connected to the air outlet 13, and the air duct 19 reaches an indoor outlet (not shown) of the air conditioning system. A fan coil (not shown) is provided inside the air duct 19 so that the air flow in the air duct 19 and the air circulation pipe 11 can be driven.

  Further, the air duct 19 of the present embodiment passes through an auxiliary cooling mechanism using well water, and the air flowing through the air duct 19 can be further cooled by the auxiliary cooling mechanism.

  Next, the operation of the underground heat exchanger 10 according to the first embodiment as described above will be described.

  When a fan coil (not shown) provided inside the air duct 19 is driven, the air inside the air duct 19 is sent to an indoor outlet (not shown) of the air conditioning system, and accordingly, air circulation is performed. Air in the pipe line 11 is sent into the air duct 19, and external air is introduced into the air circulation pipe line 11 from the air inlet 12.

  When air flows through the air circulation pipe 11, the presence of the spiral fins 15, 16 increases the time for which the air passes through the pipe 11 (residence time), and the air is sufficiently absorbed by underground heat. It is heat-exchanged and is sufficiently cooled in summer and fully heated in winter. Therefore, sufficiently cooled air is sent to the air outlet (not shown) of the air conditioning system through the air duct 19 in the summer, and sufficiently heated air is sent to the air conditioning system through the air duct 19 in the winter. To the indoor outlet (not shown).

  According to the present embodiment, the air circulation pipe 11 itself is not formed in a spiral shape, but by providing the spiral fins 15 and 16 in at least a part of the inside of the air circulation pipe 11, At least a part of the air flow path inside the circulation pipe 11 is spiral. Thereby, the passage time (residence time) of the air in the pipe line, that is, the heat exchange time between the air and the underground heat is lengthened to realize high heat exchange efficiency.

  Further, in the present embodiment, since the air circulation pipe 11 itself has a simple structure, it can be easily manufactured from a material having good thermal conductivity such as a metal, the construction cost can be suppressed, and the maintainability can be reduced. Also excellent.

  Further, in the present embodiment, when the air flow passes through the vertical straight portions 11a and 11b of the air circulation pipe 11, the spiral fins 15 and 16 swing. As a result, turbulent flow is generated, the air flow is deteriorated, the passage time (residence time) in the air pipe is further increased, and it is possible to further sufficiently exchange heat with the underground heat. Yes.

  In the present embodiment, since the spiral fins 16 are not provided in the upper region of the vertical linear portion 11b, the air after the heat exchange in the deep layer portion is unstable near the ground. It is also suppressed from being affected by natural geothermal heat.

  Next, FIG. 2 is a schematic view of a so-called coaxial double pipe type underground installation type heat exchanger according to a second embodiment of the present invention. As shown in FIG. 2, the underground heat exchanger 20 according to the present embodiment is also buried in the ground and performs heat exchange of air as a heat medium with respect to the underground heat. Yes.

  And the underground installation type heat exchanger 20 of this Embodiment also has the air flow line 21 through which the air as a heat medium distribute | circulates, the air inflow port opened to the one end side of the air flow line 21, and the air flow And an air outlet opening on the other end side of the pipe line 21.

  However, as shown in FIG. 2, unlike the first embodiment of FIG. 1, the air flow conduit 21 is formed by the space between the inner tube 22 and the outer tube 23 that are coaxially arranged. A circular cross-section pipe (outward path) 21a, a circular cross-section pipe (return path) 21b formed by the inside of the inner pipe 22, a folded portion 21c at the lower ends of the inner pipe 22 and the outer pipe 23, have.

  An upper end portion of an annular cross-section pipe (outward path) 21a opens to the ground as an air inlet, and an upper end of a circular section pipe (return path) 21b opens to the ground as an air outlet. Further, in the folded portion 21c, the inner tube 22 is formed with a bottom, and φ30 holes 22h are provided at four locations on the lower side portion of the inner tube 22, and a pipe having an annular cross section (outward path) is formed through the hole. ) Air moves from 21a to a pipe (return path) 21b having a circular cross section.

  In the present embodiment, the inner tube 22 is made of resin, and the outer tube 23 responsible for heat exchange with the underground heat is made of a metal having high thermal conductivity (for example, made of an aluminum alloy having excellent corrosion resistance and thermal conductivity). .

  A spiral fin 25 is provided in the annular passage (outward passage) 21 a of the air flow passage 21. In the present embodiment, the spiral fin 25 is provided in the entire region of the pipe section (outward path) 21a having an annular cross section and is supported by the air inlet (the upper end portion of the pipe path (outward path) 21a having an annular section). Has been.

  The spiral fins 25 of the present embodiment are formed in a smooth spiral curved surface, and both side edges thereof are 0 with respect to each inner wall of the cross-section annular pipe line (outward path) 21 a of the air circulation pipe 21. It is arranged so as to leave a gap of about 5 cm. As a result, when the air flow passes through the annular pipe line (outward path) 21a, the spiral fin 25 swings.

  The inner tube 22 of the present embodiment is made of a resin tube having a circular section of φ300, and the outer tube 23 of the present embodiment is made of a metal having a circular section of φ400 (for example, corrosion resistance and thermal conductivity). The pipes 22 and 23 have a length of about 5 m, and the spiral fins 25 are also made of metal (for example, made of an aluminum alloy having excellent corrosion resistance and thermal conductivity). is there.

  In addition, an air duct 29 is connected to an air outlet (an upper end portion of an annular cross-section pipe (outward path) 21a), and the air duct 29 reaches an indoor outlet (not shown) of the air conditioning system. In addition, a fan coil (not shown) is provided inside the air duct 29 so that the air flow in the air duct 29 and the air circulation pipe 21 can be driven.

  Further, the air duct 29 of the present embodiment passes through an auxiliary cooling mechanism using well water, and the air flowing through the air duct 29 can be further cooled by the auxiliary cooling mechanism.

  Next, the operation of the underground heat exchanger 20 according to the second embodiment as described above will be described.

  When a fan coil (not shown) provided inside the air duct 29 is driven, the air inside the air duct 29 is sent to an indoor outlet (not shown) of the air conditioning system, and accordingly, air circulation is performed. The air in the pipe 21 is sent into the air duct 29, and the outside air flows from the upper end of the cross-section annular pipe (outward path) 21a of the air flow pipe 21 as an air inlet to the cross-section annular pipe. (Outward) Introduced into 21a.

  When air circulates in the pipe line (outward path) 21a having an annular cross section, the presence of the spiral fin 25 increases the time for passing through the pipe line 11 (residence time). The heat is sufficiently exchanged with the underground heat through the pipe 23, is sufficiently cooled in the summer, and is sufficiently heated in the winter. Therefore, in the summer, sufficiently cooled air is sent to the indoor outlet (not shown) of the air conditioning system via the air duct 29, and in the winter, the sufficiently heated air is sent via the air duct 29 to the air conditioning system. To the indoor outlet (not shown).

  Also according to the present embodiment, the shape of the air circulation pipe 21 itself is not made spiral, but by providing the spiral fins 25 in the annular passage (outward path) 21a of the air circulation pipe 21. In addition, at least a part of the air flow path inside the air flow pipe 21 is formed in a spiral shape. Thereby, the passage time (residence time) of the air in the pipe line, that is, the heat exchange time between the air and the underground heat is lengthened to realize high heat exchange efficiency.

  Also in the present embodiment, since the air flow conduit 21 itself has a simple structure, it can be easily manufactured from a material having a high thermal conductivity such as metal, the construction cost can be reduced, and the maintainability can be reduced. Also excellent.

  Also in the present embodiment, the spiral fins 25 swing when the air flow passes through the annular passage (outward passage) 21a of the air circulation conduit 21. As a result, turbulent flow is generated, the air flow is deteriorated, the passage time (residence time) in the air pipe is further increased, and it is possible to further sufficiently exchange heat with the underground heat. Yes.

  Next, FIG. 3 is a schematic view of a so-called coaxial double pipe type underground installation type heat exchanger according to a third embodiment of the present invention.

  The underground heat exchanger 30 according to the present embodiment has a spiral fin 35 formed in a spiral step shape with a step instead of the spiral fin 25 formed in a smooth spiral curved surface. This is different from the underground heat exchanger 20 of the second embodiment.

  Other configurations are the same as those of the underground heat exchanger 20 according to the second embodiment. In FIG. 3, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also according to the present embodiment, substantially the same effect as the second embodiment can be obtained. That is, it is possible to increase the passage time (residence time) of the air in the pipe line, that is, the heat exchange time between the air and the underground heat, thereby realizing high heat exchange efficiency.

  Next, FIG. 4 is a schematic view of a so-called coaxial double pipe type underground heat exchanger of a fourth embodiment of the present invention.

  The underground heat exchanger 40 according to the present embodiment is provided with four (not four) spiral fins 45 to 48 formed in a smooth spiral curved surface instead of a single one. Thus, it is different from the underground heat exchanger 20 of the second embodiment.

  Other configurations are the same as those of the underground heat exchanger 20 according to the second embodiment. In FIG. 4, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also according to the present embodiment, substantially the same operational effects as those of the fourth embodiment can be obtained. That is, it is possible to increase the passage time (residence time) of the air in the pipe line, that is, the heat exchange time between the air and the underground heat, thereby realizing high heat exchange efficiency.

  In each of the above embodiments, the spiral fins 15, 16, 25, 35, 45, 46, 47, 48 may be provided with many holes. In this case, the turbulent flow is further generated, the air flow is deteriorated, the passage time (residence time) of the air in the pipe line is further increased, and the heat exchange with the underground heat can be further sufficiently performed. . Such a configuration can be realized by adopting punching plates for the spiral fins 15, 16, 25, 35, 45, 46, 47, 48.

  Irregularities may be provided on the surfaces of the spiral fins 15, 16, 25, 35, 45, 46, 47, 48 instead of or in addition to many holes. Also in this case, the turbulent flow is generated, the air flow is deteriorated, the passage time (residence time) in the air pipe is further increased, and it is possible to further sufficiently exchange heat with the underground heat. Become.

DESCRIPTION OF SYMBOLS 10 Underground installation type heat exchanger 11 Air distribution pipe 11a Vertical linear part 11b Vertical linear part 11c Folded part 12 Air inlet 13 Air outlets 15 and 16 Spiral fins 17 and 18 Support rod Part 19 Air duct 20 Underground heat exchanger 21 Air circulation pipe 21a Pipe having an annular cross section (outward path)
21b Pipe with circular cross section (return)
21c Folding portion 22 Inner tube 22h Hole 23 Outer tube 25 Spiral fin 29 Air duct 30 Underground heat exchanger 35 Spiral stair fin 40 Underground heat exchanger 45-48 Quadruple (4) Spiral fins

Claims (8)

An underground heat exchanger that is buried in the ground and performs heat exchange of the heat medium against the underground heat,
An air circulation pipe through which air as a heat medium circulates;
An air inlet opening at one end of the air circulation pipe;
An air outlet opening on the other end side of the air circulation pipe;
A helical fin provided in at least a part of the inside of the air circulation pipe;
An underground heat exchanger characterized by comprising: 2. The underground heat exchanger according to claim 1, wherein the spiral fins are installed so as to be swingable inside the air circulation pipe. The underground heat exchanger according to claim 1 or 2, wherein the spiral fin has a portion that transitions into a smooth spiral curved surface. The underground heat exchanger according to claim 1 or 2, wherein the spiral fin has a portion that changes in a spiral staircase shape with a step. The underground heat exchanger according to any one of claims 1 to 4, wherein the spiral fin is provided with a hole. 6. The underground heat exchanger according to any one of claims 1 to 5, wherein the air circulation pipe has a pipe folded back in a substantially U shape. 6. The air circulation pipe according to claim 1, wherein the air circulation pipe has a pipe having an annular cross section formed by a space between an inner pipe and an outer pipe arranged coaxially. An underground heat exchanger as described in Crab. The inner tube is made of resin,
The outer tube is made of metal;
The underground heat exchanger according to claim 7, wherein the spiral fin is disposed in the pipe having an annular cross section.

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