JP2010261633A - Multiple-tube for heat exchanger and geothermal air conditioning system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To economically construct a geothermal air conditioning system exchanging heat with ground heat. <P>SOLUTION: In this air conditioning system constituted by burying a tubular body in the ground to exchange heat between a fluid inside of the tubular body and the ground heat, an underground tube 1 is composed of a triple-tube of an inner tube 11, an intermediate tube 12 and an outer tube 13, an intermediate layer is vacuum and has a heat insulating property, and a liquid is made to flow into the inside of the outer tube 13 at a terminal end section above ground, and turn down at a tip section in the ground to be returned on ground from the inner tube 11. As a length of the underground tube 1 is determined to a length enough to exchange heat, and it is unnecessary to make the underground tube penetrate above ground at an opposite side, the geothermal air conditioning system can be economically constructed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a heat exchange multiple pipe in an air conditioning system in which piping is buried in the ground and heat exchange is performed between an internal fluid and ground heat, and a ground heat utilization air conditioning system using the same.

  The present applicant has previously developed an air conditioning system in which piping is buried in the ground and heat is exchanged between the internal fluid and the underground heat. First, this will be briefly described.

  FIG. 6 is a configuration diagram showing the ground heat utilization air conditioning system invention described in Patent Document 1. Reference numeral 1 is underground piping, reference numeral 2 is a circulation pump of liquid such as refrigerant, reference numeral 3 is a heat exchanger, reference numeral 4 is The blower, reference numeral 7 is a circulation tank, and reference numeral R is an air-conditioned space.

  A ground heat-use air conditioner that circulates liquid between the underground pipe 1 buried in the ground and the heat exchanger 3 on the ground, and heats and cools the air-conditioned space R in the building by the heat obtained from the heat exchanger 3 In this system, the underground pipe 1 is laid in a substantially arc shape across the lower part of the building.

  This is because the ground temperature in the ground 10 to 15m or less from the ground surface excluding the surface layer (hereinafter referred to as "constant temperature layer" or "aquifer") is approximately 15 Focusing on the fact that the temperature is 16 ° C., a liquid is circulated between the underground pipe buried in the thermostatic layer and the heat exchanger on the ground, and the inside of the building is cooled and heated by the heat obtained from the heat exchanger. The medium-heat-use air conditioning system has a temperature range of 15 to 16 ° C., which is slightly lower as the target temperature for heating, but is rather too low for cooling. If it can be maintained within the range, an ideal air conditioning system will be realized.

  The underground pipe 1 is buried in the lower part of the building, so there is no need to work outside the building site and it is not necessary to acquire a new site for laying. If it is going to embed the pipe, it will be necessary to consider installing a shaft to serve as a starting base for horizontal boring outside the building, or adopting a special construction method.

  Patent Document 2 describes a non-cutting boring machine (hereinafter referred to as “digging machine”) using a flexible rod, which has been recently developed in the United States, and a method of using the same. This will be briefly described with reference to FIGS.

  FIG. 7 is a conceptual diagram showing this known excavation method. Reference numeral 1A is a flexible connecting rod corresponding to the underground pipe 1, reference numeral 6 is an excavation head, reference numeral 7 is an excavator, and reference numeral S is a structure. is there. Since the boring is started obliquely from the ground beside the structure S toward the ground, the direction of the excavation head is changed to the horizontal direction when reaching the predetermined depth, that is, the above-mentioned constant temperature layer, and thereafter the horizontal boring is performed is there. Here, “horizontal” includes not only being completely horizontal, but also an inclined state (for example, about ± 10 °) within a range allowed for normal excavation.

  FIG. 8 is a cross-sectional view of the excavation head 6 described in Patent Document 2. Reference numeral 61 denotes a jet nozzle, and reference numeral 62 denotes a fluid path through which high-pressure fluid is supplied. In this example, the jet nozzle 61 is inclined at about 5 degrees with respect to the central axis of the digging head 6. Accordingly, if the advancing head 6 is moved forward while being rotated, it moves straight, but if it is moved forward without being rotated, it proceeds in an oblique direction according to the direction of the jet nozzle 61.

  FIG. 9 is an external view of the excavator described in Patent Document 2. Reference numeral 7 is an excavator, reference numeral 70 is a base, reference numeral 71 is a forward frame that moves on the excavator, reference numeral 72 is a motor for rotation, and reference numeral 73 is a chain. Reference numeral 74 denotes a forward motor. The forward frame 71 is provided with a clamp for fixing the connecting rod 1A and a chuck for gripping and rotating the connecting rod 1A. When the advance mechanism is combined with this, the connecting rod 1A is moved forward without rotating, or rotated. You can make it move forward.

  If the connecting rod 1A is constituted by a hollow tube and is left in the ground after excavation, it becomes an underground pipe as it is. However, when a connecting rod 1A other than the tube is used for the convenience of construction, it is penetrated. What is necessary is just to make it connect to a connecting rod 1A later and to draw in in the ground.

JP 2007-64549 A JP-A 61-257501

  If the underground piping has a substantially circular arc shape as shown in FIG. 6, it can be constructed by the excavator described in Patent Document 2, but to reach the ground on the opposite side across the bottom of the building. Excessive length of drilling is required, sometimes exceeding the length required for heat exchange, which is very uneconomical.

  In the present invention, the connecting rod is composed of a tubular body, and this tubular body is a multiple tube, so that the underground excavation length is limited to the limit necessary for heat exchange, and the heat with the underground heat is economically constructed. The purpose is to achieve the exchange.

  The present invention as set forth in claim 1 is a long multiple pipe of at least 10 m or more for horizontally exchanging in a constant temperature layer of the ground and exchanging heat between the internal fluid and the surrounding underground heat. A tube and an outer tube surrounding the tube, or a multiple tube including at least one layer of an inner tube and an outer tube surrounding the tube, the outer tube is closed at a tip, and the inner tube is a tip of the outer tube The heat exchanging pipe is characterized in that a pipe path reciprocating between the inner pipe and the space surrounded by the outer pipe and the inner pipe is formed.

The present invention according to claim 2 is the multiple tube for heat exchange according to claim 1, wherein the diameter of the inner tube is equal to or less than (1/2) ^1/2 of the diameter of the outer tube.

  According to a third aspect of the present invention, the inner pipe is made of a material having a low thermal conductivity, and the outer pipe is made of a material having a high thermal conductivity. It is a multiple tube for heat exchange.

  According to a fourth aspect of the present invention, a heat insulating layer made of a material having low thermal conductivity is provided on the outer periphery of the inner tube, and the outer tube is made of a material having high heat conductivity. Item 3. The heat exchange multiple tube according to Item 1 or 2.

  The present invention according to claim 5 is characterized in that the outer periphery of the inner tube is surrounded by at least one layer of inner tube, and both ends of the enclosed portion are closed to form a heat-insulating layer in a vacuum state. Item 5. A heat exchange multiple tube according to Item 4.

  Furthermore, in the present invention described in claim 6, the inner tube of the heat exchange multiplex tube embedded in the constant temperature layer of the ground in the horizontal direction is extended in the tube length direction, and a plurality of peripheral holes closed at both ends are formed. The multi-tube for heat exchange according to claim 1 or 2, wherein the heat transfer medium is sealed in the peripheral hole.

  According to the seventh aspect of the present invention, a liquid is circulated between an underground pipe buried horizontally in a constant temperature layer of the ground and a heat exchanger on the ground, and heat is obtained from the heat exchanger. A geothermal air conditioning system for cooling and heating an air-conditioned space in the interior, wherein the underground pipe is the multiple pipe for heat exchange according to any one of claims 1 to 5. It is.

  In the present invention, the “horizontal direction” is not limited to a completely horizontal direction, and includes a direction inclined at a predetermined angle within a range not impairing the object of the present invention, for example, about ± 10 ° It may be the direction in which

  According to the present invention, since it is only necessary to make the underground pipe as long as necessary for heat exchange with the underground heat, an excellent effect is achieved that the underground heat utilization air conditioning system can be constructed economically and efficiently. .

It is sectional drawing of the multiple tube of the 1st Example of this invention. It is sectional drawing of the perforated pipe with a fin in the 2nd Example of this invention. It is a conceptual diagram which shows the embedment state of the multiple pipe | tube of this invention Example. It is a block diagram of the underground heat utilization air conditioning system of an Example of this invention. It is explanatory drawing explaining the cross-sectional dimension of the multiple tube | pipe of this invention. It is a block diagram of the underground heat utilization air conditioning system in a prior art. It is a conceptual diagram of the conventionally well-known excavation method concerning this invention. It is sectional drawing of the excavation head in a prior art. It is an external view of the excavator in the prior art.

  The cross-sectional dimensions that the multiple tube of the present invention should have will be described with reference to the drawings using an example of a double tube.

FIG. 5A shows a cross section of the double tube, where the radius of the outer tube is r ₁ , the radius of the inner tube is r ₂ , the circumference of the outer tube is L ₁ , and the circumference of the inner tube is L ₂ .

In the present invention, and the inner tube, since the reciprocating fluid in the space surrounded by the outer tube and the inner tube, the cross-sectional area of surrounded by the outer tube and the inner tube portion as shown in (b) S ₁ , and the cross-sectional area of the inner tube and S _2, if the reciprocating flow are equal,
S ₁ = S ₂
And
π (r ₁ ² −r ₂ ² ) = π · r ₂ ²
It becomes. Since r ₂ > 0,
r ₁ = r ₂ ^1/2
It becomes. This is a limit value, and it is not preferable that r ₁ be less than this.

At this time,
L ₁ = L ₂ ^1/2
Therefore, the contact area between the outer tube and the surrounding strata is 2 ^1/2 times larger than the contact area between the water inside the outer tube and the water in the inner tube.

If r ₁ is larger than this, or if r ₂ is smaller than this, the ratio of the contact areas is further increased.

At this time, the internal flow rate is
S ₁ = S ₂
However, if the inner tube becomes relatively thin with respect to the outer tube, the inner flow becomes faster with respect to the outer flow, and heat exchange with the underground heat takes place slowly. The heat exchange (heat loss) of can be discharged without much.

From the above,
(1) The diameter of the inner tube is made thinner than (1/2) ^1/2 times the outer tube.
(2) A material with high thermal conductivity (copper, aluminum, etc.) is used for the outer tube, and a material with low thermal conductivity (stainless steel, etc.) is used for the inner tube.
(3) A heat insulating layer is provided between the outer tube and the inner tube, or a vacuum layer is provided.
(4) Promote heat exchange with the outside by using a heat pipe in the inner pipe.
As a result, the heat exchanged with the formation can be extracted outside with less internal loss. Insulation between the outer pipe and the inner pipe is particularly effective when the air conditioning system is intermittently operated day and night.

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

  FIG. 1 is a cross-sectional view showing a multiple pipe which is an underground pipe of the first embodiment. Reference numeral 11 is an inner pipe, reference numeral 12 is an inner pipe, reference numeral 13 is an outer pipe, and reference numeral 14 is a check during vacuum processing. It is a valve. As shown in FIG. 7, the multiple pipes are sequentially connected to the rear of the digging head 6 via a joint as the digging progresses, and have flexibility to follow the bending of the piping path. Have. In FIG. 1, the middle portion is omitted and the tip portion and the end portion are shown. The structure is a multiple tube comprising an inner tube 11, an inner tube 12 surrounding the inner tube 11, and an outer tube 13 surrounding the inner tube 12, and the inner tube 11 and the inner side of the outer tube 13 are electrically connected at the tip. In addition, the space surrounded by the inner tube 11 and the inner tube 12 is closed at both ends of the multiple tube 1, and the inside is vacuumed to provide heat insulation. At the end portion on the ground, for example, the outer tube 13 and the middle tube The liquid for heat exchange is made to flow into the pipe | tube with 12, and it is made to flow out from the inner pipe | tube 11. FIG. The direction of the flow may be reversed. Instead of evacuating the space, the inner tube may be covered with a heat insulating material. In any case, since the space surrounded by the inner tube 11 and the inner tube 12 is a heat insulating layer, the fluid flowing from the outside and the fluid flowing out from the inner tube are not adjacent to each other. Returns to the ground as it is, with little loss.

  Although FIG. 1 shows an example of a triple pipe, the heat insulating layer may be further increased as a quadruple pipe.

  FIG. 2 is a cross-sectional view showing a perforated tube in the second embodiment. Reference numeral 11A is a perforated tube, reference numeral 111 is a fin (fin) for heat transfer provided on the inner and outer surfaces, and reference numeral 112 is a plurality of peripheral holes extending in the tube length direction and closed at both ends. In this embodiment, such a finned perforated tube is used as the inner tube, and a heat medium is enclosed in the peripheral hole 112 to form a so-called “heat pipe”, which performs heat transfer on both sides of the inner tube. Promote. Needless to say, fins are used to increase the heat transfer area, and may not be provided in some cases, or waves may be formed on the surface instead of fins. If fins and waves are also provided on the inner surface of the peripheral hole, it will help convection of the internal heat medium. In addition, the porous tube of such a shape can be manufactured by extrusion molding, such as aluminum.

  The heat medium is also called a heat medium, and is a general term for fluids used to move heat, but in a broad sense includes non-fluids such as sand and resin powder. It is desirable that it has a large heat capacity or large latent heat, and is itself non-flammable, non-toxic and inexpensive, and many substances are known, such as chlorofluorocarbon, carbon dioxide, brine, ammonia, silicon oil, and sand. When accompanied by a change in the phase of gas, liquid, etc., it is only necessary to select a gas whose pressure or temperature changes according to the use conditions.

  FIG. 3 is a conceptual diagram showing a buried state of the multiple pipe of the present invention, and reference numeral 1 denotes the multiple pipe. A long multiple tube of at least 10 m or more is embedded in the constant temperature layer of the ground in a substantially horizontal direction, and the liquid is circulated between the multiple tube 1 and the ground as indicated by a solid line arrow or a broken line arrow. Thus, even if there are buildings, facilities, trees, etc. on the ground, the multiple pipe of the present invention can be buried without hindrance by setting it to a sufficient depth.

  FIG. 4 is a block diagram of the underground heat utilization air conditioning system using the multiple pipe of the present invention, and the underground pipe 1 is a triple pipe as shown in FIG. Since it functions as a connecting rod during excavation, it has flexibility, and new ones are sequentially connected to the rear as the excavation progresses. It is sufficient that the underground pipe 1 has a necessary and sufficient length for heat exchange with the underground heat in the thermostatic layer, and as is apparent from comparison with FIG. 5, for reaching the ground on the opposite side. Construction is extremely economical because it can be much shorter than the length.

  The example in which the multiple pipe is used as the connecting rod for excavation has been described above. However, the excavation work may be performed only with the outer pipe, and the inner pipe may be inserted into the interior after the excavation. In this case, since it is not necessary to hold the inner tube at the center position of the outer tube, a holding tool or the like is unnecessary, and it may be simply inserted.

  From the viewpoint of heat collection and heat dissipation, a steel pipe or copper pipe with high thermal conductivity is preferable as the outer pipe, and a stainless steel pipe or vinyl chloride resin pipe with low thermal conductivity is preferable as the inner pipe.

  DESCRIPTION OF SYMBOLS 1 ... Underground piping, 1A ... Connecting rod, 2 ... Circulation pump, 3 ... Heat exchanger, 4 ... Blower, 5 ... Circulation tank, 6 ... Digging head, 7 ... Digging machine, 11 ... Inner pipe, 11A ... Porous pipe 12 ... Medium pipe, 13 ... Outer pipe, 14 ... Check valve, 61 ... Jet nozzle, 62 ... Fluid path, 71 ... Advance frame, 72 ... Motor for rotation, 73 ... Chain, 74 ... Motor for advance, 111 ... Fins 112 ... Circumferential hole R ... Space to be air conditioned S ... Structure

Claims (7)

  A long multiple pipe of at least 10 m or more, which is buried in the constant temperature layer of the ground in a horizontal direction and exchanges heat between the internal fluid and the surrounding underground heat, and includes an inner pipe and an outer pipe surrounding the inner pipe, or It is composed of a multiple tube composed of at least one layer of an inner tube and an outer tube surrounding the outer tube, and closes the outer tube at the tip, and opens the inner tube at the tip of the outer tube, A heat exchanging multiple pipe characterized in that a pipe path reciprocating between a space surrounded by the outer pipe and the inner pipe is formed. The multiple tube for heat exchange according to claim 1, wherein the diameter of the inner tube is equal to or less than (1/2) ^1/2 of the diameter of the outer tube.   The multiple tube for heat exchange according to claim 1 or 2, wherein the inner tube is made of a material having a low heat conductivity, and the outer tube is made of a material having a high heat conductivity.   The heat exchanger according to claim 1 or 2, wherein a heat insulating layer made of a material having low thermal conductivity is provided on an outer periphery of the inner tube, and the outer tube is made of a material having high heat conductivity. Multiple tubes.   5. The heat exchanging multiple tube according to claim 4, wherein the outer periphery of the inner tube is surrounded by at least one layer of an inner tube, and both ends of the enclosed portion are closed to form a heat-insulating layer in a vacuum state. .   The inner pipe in the heat exchange multiplex pipe embedded in the constant temperature layer of the ground in the horizontal direction is composed of a perforated pipe extending in the pipe length direction and having a plurality of peripheral holes closed at both ends. The multiple tube for heat exchange according to claim 1 or 2, wherein a medium is enclosed.   Geothermal heat that circulates liquid between underground piping horizontally embedded in the thermostatic layer of the ground and the heat exchanger on the ground, and heats and cools the air-conditioned space in the building with the heat obtained from the heat exchanger In a utilization air-conditioning system, the underground piping is the multiple pipe | tube for heat exchange in any one of Claim 1 thru | or 6, The geothermal utilization air-conditioning system characterized by the above-mentioned.

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