JP2016217688A - Underground heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat collection efficiency of a circulation type underground heat utilization facility, reduce installation cost and maintenance and to enable this invention to be adapted for a high-capacity heat exchanging operation.SOLUTION: A tubular lining member with its extremity end being closed is inserted into a hole drilled in the ground, hardened under a state in which it is closely contacted with concave or convex peripheral surface of an excavation hole to make the excavation hole into a heat exchanger.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a structure of a geothermal heat exchanger in which water and a heat exchange medium are circulated through a hole excavated underground for the use of geothermal heat and the geothermal heat is effectively utilized.

  While geothermal heat uses natural resources directly, it has the advantage of being environmentally friendly and economical. On the other hand, in order to obtain the required heat, a hole with a depth of several tens to hundreds of meters can be formed in the ground. It has to be excavated and a large number of underground heat exchange devices must be buried, and the installation cost is extremely high. In order to solve this problem, it is necessary to reduce the cost of the heat exchange device itself and increase the heat collection efficiency of the underground heat exchange device.

As a conventional circulating type geothermal heat utilization equipment, for example, a vertical type underground heat exchange device excavates a vertical hole in the ground, inserts a pipe material into the vertical hole, and inserts into the gap between the vertical hole and the pipe material. Some have a structure filled with backfill material.
The inserted pipe is bent into a U shape at the deepest part of the excavation hole and returned to the ground. The heat exchange liquid that passes through the pipe material collects the geothermal heat and transports it to the ground. There is also a method of embedding a plurality of U-shaped ridges.

  In this method, the reciprocating rods bent into a U-shape underground are close to each other in the ground, and therefore, a part of the heat quantity of the heat exchange liquid that rises by collecting heat in the underground is dissipated on the ground. It is inefficient because it moves to the low-temperature return soot that descends. When the temperature on the ground is high, the heat exchange liquid that radiates and rises underground absorbs part of the heat of the high-temperature return rod that is heated on the ground and descends underground.

  In addition, the area for the heat exchange liquid to collect ground heat or to dissipate heat to the ground is limited to the outer diameter of the cage that carries the heat exchange liquid.

Therefore, in order to enhance the heat collection effect, a method has been devised in which the contact with the underground surface is increased and the capacity of the underground heat exchange liquid is increased.
For example, heat exchange liquid such as antifreeze liquid is put into the hollow part of the foundation pile buried in the ground, a water intake pipe and an injection pipe are connected to the hollow part, a feed pipe is connected to the intake pipe, and a feed pipe is connected to the injection pipe. There is a heat exchange system in which return pipes are connected to each other, the heat exchange liquid is sent to a heat exchange section that is piped and installed at a predetermined place, and returned to the foundation pile by circulation.

Reference 1

Japanese Utility Model 05-05429

A so-called coaxial type has been devised. This is composed of an outer tube that is in contact with the ground via a backfill material, and a coaxial double tube that is an inner tube disposed in the outer tube.
The heat exchange liquid circulated and recovered from the ground descends deeply underground through the inner pipe. And it inverts in the lowest part, returns to the ground, exchanging heat with the underground through the gap between the outer tube and the inner tube. Alternatively, the reverse path may be taken. On the ground, the heat exchange liquid discharged from the underground heat exchanger is connected to the ground heat exchange section. Here, the heat exchange liquid discharged after finishing the heat exchange is returned to the underground heat exchanger again.

  Then, in order to allow the heat exchange liquid flowing through the gap between the outer pipe and the inner pipe to efficiently collect heat from the outer pipe, it is necessary to make the flow of the heat exchange liquid turbulent. For this purpose, the ratio of the outer diameter of the inner tube to the inner diameter of the outer tube is set to 0.70 or more and 0.95 or less, and projections are provided on the inner peripheral surface of the outer tube and / or the outer peripheral surface of the inner tube to roughen the surface. There is what I did.

Reference 2

JP 2004-309124 A

However, in the underground heat exchange apparatus shown in the above-mentioned documents 1 and 2, in the case of a metal structure, the heat conduction effect is high, but the cost is high. In addition, when the outer diameter of the outer tube is increased, the outer tube has a joint coating structure in consideration of cost and heat collection effect, and it is necessary to perform maintenance on it. Large-scale repairs such as removing the buried pipes were necessary.
In the case of steel structures, corrosion always occurs and the service life is short.

  Further, in the underground heat exchange device shown in the above-mentioned literatures 1 and 2, in the case of a concrete structure, since the heat exchange liquid such as antifreeze liquid circulates in the hollow portion of the concrete foundation pile, the calcium content contained in the concrete is Reacts with the liquid to precipitate calcium carbonate crystals. Since this crystal adheres to the inside of the pipe, it must be frequently removed. Therefore, the maintenance cost is high, and the inside of the pipe is often clogged, resulting in a failure.

  In order to prevent leakage due to metal breakage and precipitation of calcium carbonate crystals, the hollow portion of the pile may be coated, but not only the cost increases, but also the reliability is low, such as peeling and cracking.

In order to solve the above problems, the present invention employs the following means.
That is, in the underground heat exchanger according to the present invention, a tubular lining material having a closed tip is inserted into a hole excavated in the ground, and the lining material is in close contact with the uneven shape of the peripheral surface of the excavation hole. It is characterized by being cured in the state.

  As one form of the underground heat exchanger, the tubular lining material inserted into the excavated hole is impregnated with a thermosetting resin.

  As an underground heat exchanger in another form, the tubular lining material inserted into the excavated hole is impregnated with an ultraviolet curable resin.

  Furthermore, as an underground heat exchanger in another form, a tubular lining material inserted into the excavated hole is impregnated with a time-hardening material.

  The utilization form of the underground heat exchanger according to any one of the above is such that a heat exchange liquid such as water or antifreeze is maintained in the hollow part, and a water intake pipe and an injection pipe are installed in the hollow part. And the said pouring bowl is connected with the heat exchange part installed and installed in the predetermined place, It is characterized by the above-mentioned.

  In the construction method of the underground heat exchanger according to the present invention, a tubular lining material having a closed end is inserted into a hole excavated in the ground, and a liquid under pressure is injected into the lining material. Is expanded, and the lining material is cured while being kept in close contact with the uneven surface of the excavation hole, and the excavation hole is lined to form a heat exchanger.

  As one form of the construction method of the underground heat exchanger, the lining material is impregnated with a thermosetting resin, inserted into the excavation hole together with the pipe inserted into the lining material, and pressure is applied through the pipe. While inflating the lining material by injecting liquid and keeping in close contact with the concave and convex peripheral surface of the excavation hole, hot water is injected through the pipe to contact the lining material, and the thermosetting impregnated in the lining material The heat-resistant resin is cured and the excavation hole is lined to form a heat exchanger.

  As one form of construction method of the underground heat exchanger in different forms, the lining material is impregnated with thermosetting resin, and the lining material is turned over before being inserted, and excavation The mouth of the lining material turned upside down on the peripheral surface of the hole at the entrance of the hole is brought into close contact with the surface, injected with liquid under pressure to expand the lining material, and in close contact with the uneven surface of the drilling hole, Inserting from the top of the drilling hole sequentially while returning to the table, let the closed tip of the lining material reach the deepest part of the drilling hole, inject hot water through the pipe inserted into it, contact the lining material, the lining The thermosetting resin impregnated in the material is cured, and the excavation hole is lined to make the excavation hole a heat exchanger.

  Furthermore, as an underground heat exchanger in a different form, a tubular lining material having a closed tip is inserted into a hollow portion of a hollow pile inserted into the ground, and the lining material is an inner peripheral surface of the hollow pile. It hardens | cures in the state closely_contact | adhered to.

  According to the present invention, the formation of the hollow portion for storing the heat exchange liquid can be achieved by using heat, ultraviolet rays, or time hardening in a hole excavated in the ground, instead of embedding a conventional steel pipe or concrete pile in the ground. Insert a tubular lining material impregnated with a porous resin, expand it, and in close contact with the peripheral surface of the concave and convex shape of the drilling hole, cure the curable resin impregnated in the lining material and line the drilling hole To do.

  Alternatively, the hollow part for storing the heat exchange liquid is formed by inserting a hollow pile made of concrete or metal into the ground, inserting a tubular lining material with a closed end into the hollow pile, and inserting the lining material into the hollow It hardens | cures in the state closely_contact | adhered to the internal peripheral surface of a pile, and linings the hollow part of a hollow pile.

In any one of the hollow portions, an injection pipe and a water intake are connected to the ground heat exchange unit.
The heat exchange liquid circulated from the heat exchange part such as the snowmelt pipe on the ground reaches the lowest part of the underground heat exchange hole through the injection pipe and is injected into the hollow part of the underground heat exchanger. The injected heat exchange liquid has a lower temperature than the ground because heat is exchanged on the ground. The low-temperature heat exchange liquid reaches the upper intake port while absorbing the underground temperature from the lowermost part of the underground heat exchange hole.

  Since the hardened lining material is formed in the concave / convex shape of the excavation hole on the inner surface of the hollow portion, the flow of the rising heat exchange liquid becomes a turbulent flow, and the underground heat is efficiently collected.

  According to this method, the hollow portion holding the heat exchange liquid is made of a curable resin, and can be constructed at a lower cost than embedding a steel pipe or a concrete pile, and maintenance such as welding and painting is not performed.

  Further, since it does not come into contact with concrete, calcium carbonate crystals are not precipitated, and troubles such as clogging in the pipe are eliminated, and maintenance costs can be reduced.

  In addition, when the underground heat exchanger is installed, the excavation hole is filled with groundwater, but the lining material is inserted into the excavation hole together with the pipe inserted into the lining material, and a pressurized liquid is injected through the pipe. Thus, the groundwater pressure in the excavation hole can be overcome and the lining material can be easily expanded and brought into close contact with the peripheral surface of the hole.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, the underground heat exchanger (g) according to the present invention is excavated by inserting and expanding a tubular lining material (a) impregnated with a thermosetting resin into an underground excavation hole (h). In a state where the peripheral surface of the hole is pressed in a concavo-convex shape, hot water is injected through the injection tube (d), and the lining material (a) is contacted and cured to form an uneven lining surface (i). is there.

  In FIG. 2, the underground heat exchanger (g) is provided with an injection pipe (d) and a water intake trough (c) connected to the ground heat exchanger (e), and filled with a heat exchange liquid (b). . The intake trough (c) is connected to the heat exchange part (e) through a pump (f).

Explanation of operation during operation (Fig. 2)
(1) The pump (f) is activated, and the heat exchange liquid (b) pumped up from the intake tank (c) is sent to the heat exchange section (e).
(2) In the heat exchange part (e), the heat of the heat exchange liquid (b) warmed by the underground heat is released.
(3) In the heat exchanging section (e), for example, cooling / heating of buildings, snow melting on roads, freezing prevention, road cooling, and the like are performed.
(4) The heat exchange liquid (b) that releases heat and is cooled in the heat exchange section (e) passes through the injection pipe (d) and reaches the lower part of the underground heat exchanger (g).
(5) The heat exchange liquid (b) that has reached the lower part of the underground heat exchanger (g) is warmed by the underground heat, rises, and is taken up at the upper part of the underground heat exchanger (g). Reach the water intake of 菅 (c).
(6) When the heat exchange liquid (b) rises in the underground heat exchanger (g), it is stirred by the uneven lining surface (i) and the like, so that the underground heat can be collected effectively. it can.
(7) Therefore, the heat exchange liquid (b) warmed in the ground is taken from the water intake trough (c).

Other examples

The present invention is by no means limited to that shown in the above-described embodiment, and various design changes can be made within the scope of the claims. An example is as follows.
(1) Although the underground heat exchanger according to the present invention is excavated substantially perpendicularly to the ground surface, it may be excavated in the horizontal direction on the ground surface after excavating perpendicularly to a predetermined depth.

(2) The underground heat exchange hole according to the present invention can be used not only for air conditioning, snow melting, and heat island countermeasures but also for all uses.

  The form which concerns on the underground heat exchanger of this invention is shown.   The best embodiment concerning the underground heat exchanger of the present invention is shown.

a. Lining material b. Heat exchange liquid c. Intake water d. Injection tube e. Heat exchanger f. Pump g. Underground heat exchanger h. Drilling hole i. Lining surface

Claims (9)

  A tubular lining material with a closed tip is inserted into a hole excavated in the ground, and the lining material is hardened in close contact with the uneven surface of the excavated hole. Underground heat exchanger   The underground heat exchanger according to claim 1, wherein the tubular lining material inserted into the excavated hole is impregnated with a thermosetting resin.   2. The underground heat exchanger according to claim 1, wherein the tubular lining material inserted into the excavated hole is impregnated with an ultraviolet curable resin.   2. The underground heat exchanger according to claim 1, wherein the tubular lining material inserted into the excavated hole is impregnated with a time-hardening substance.   5. The underground heat exchanger according to claim 1, wherein a heat exchange liquid such as water or an antifreeze is maintained in the hollow portion, and a water intake pipe and an injection pipe are installed in the hollow portion. The underground heat exchanger is characterized in that the intake trough and the infusion trough are connected to a heat exchanging section that is piped and installed in a predetermined place.   Insert a tubular lining material with a closed tip into the hole drilled into the ground, inject liquid under pressure to expand the lining material, and adhere to the uneven surface of the drill hole The construction method of the underground heat exchanger is characterized by curing the lining material and lining the excavation hole to make the excavation hole into a heat exchanger while keeping it in a maintained state.   The construction method of the underground heat exchanger according to claim 6, wherein the lining material is impregnated with a thermosetting resin, inserted into the excavation hole together with the pipe inserted into the lining material, and pressure is applied through the pipe. The lining material is expanded by injecting the liquid, and hot water is injected through the pipe and brought into contact with the lining material while being kept in close contact with the uneven surface of the excavation hole, and the heat impregnated in the lining material Construction method of underground heat exchanger characterized by curing curable resin and lining the excavation hole to make the excavation hole a heat exchanger   7. The construction method of the underground heat exchanger according to claim 6, wherein the lining material is impregnated with a thermosetting resin, and the lining material is turned over before being inserted, Return the lining material's mouth that is turned over to the perimeter of the perforated hole to the front and close it, inject liquid under pressure to expand the lining material, and bring it back to the front while closely contacting the uneven surface of the drilling hole While inserting from the upper part of the drilling hole in order, the closed tip of the lining material reaches the deepest part of the drilling hole, hot water is injected through the pipe inserted into the lining material, and the lining material is impregnated. Of underground heat exchanger characterized in that the excavated hole is turned into a heat exchanger by curing the cured thermosetting resin and lining the excavated hole   A tubular lining material having a closed tip is inserted into a hollow portion of a hollow pile inserted into the ground, and the lining material is cured in a state of being in close contact with an inner peripheral surface of the hollow pile. Underground heat exchanger

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