JP4632905B2 - Geothermal air conditioning system - Google Patents

Description

  The present invention relates to a pollution-free and economical air conditioning system that uses geothermal heat.

  Paying attention to the fact that the underground temperature in the ground excluding the surface layer (hereinafter referred to as “constant temperature layer”) is approximately 15 to 16 ° C. throughout the year, the heat exchange between the underground pipe buried in the constant temperature layer and the ground Various air-conditioning systems using geothermal heat have been proposed in which a liquid is circulated between the units and the inside of the building is cooled and heated by heat obtained from the heat exchanger. The temperature range of 15 to 16 ° C. is slightly lower as the target temperature for heating, but is too low as the target temperature for cooling, so long as the interior of the building can be efficiently maintained at the above temperature. An ideal air conditioning system is realized throughout the year.

First, the air conditioning system described in Patent Document 1 will be briefly described with reference to the drawings.
FIG. 3 is a configuration diagram of an air conditioning system described in Patent Document 1. 1 is an underground pipe (underground pipe), 2 is a liquid circulation pump, 3 is a heat exchanger, and 4 is a blower. In this air conditioning system, a liquid is passed through the underground pipe 1, the ground heat is given to the liquid and circulated through the heat exchanger 3, and the air exchanged with the liquid by the blower 4 is under the floor of the building, inside the wall, attic, etc. The inside of the building is air-conditioned by circulating it. The laying of the underground pipe 1 is supposed to be drilled vertically in the middle depth of the underground. The liquid is, for example, water.

Next, the geothermal heat utilization system described in Patent Document 2 will be briefly described with reference to the drawings. FIG. 4 is a configuration diagram showing a state of cooling operation, (b) is a state of heating operation, and 5 is a compressor in an embodiment of the geothermal air conditioning system described in Patent Document 2. 6 is a four-way valve, 8 is a condenser, 9 is an expansion valve, 10 is an evaporator, 11 is a refrigerant pipe, and R is an air-conditioned space.
This underground heat-utilizing air conditioning system connects the underground heat exchanger (underground piping) 1 buried in the ground and the heat pump so that heat exchange is possible, and exchanges heat between the heat pump, the air-conditioned space, and the atmosphere. The heat pump is connected to the underground heat exchanger, heat pump, and air-conditioned space to heat and cool the air-conditioned space while dissipating heat or collecting heat. 8, an expansion valve 9, an evaporator 10, a refrigerant pipe 11 that circulates the refrigerant by connecting them, and a four-way valve 6 that switches the refrigerant flow in the forward and reverse directions. The refrigerant pipe 11 that exchanges heat with the filler filled in 1 functions as the condenser 8 of the heat pump, dissipates heat into the ground, exchanges heat between the evaporator 10 of the heat pump and the air-conditioned space 7 and covers the heat. Air-conditioned space 7 is cooled. Moreover, in (b), the refrigerant | coolant piping 11 which heat-exchanges with the filler with which it filled in the underground heat exchanger functions as the evaporator 10 of a heat pump, heat-collects from underground, the condenser 8 of a heat pump, and to-be-air-conditioned Heat exchange is performed between the space 7 and the air-conditioned space 7 is heated.

The underground heat exchanger 1 is applicable to all members in contact with the ground such as boreholes, pile foundations, direct foundations, and underground continuous walls formed in the ground. It is the water, grout, etc. with which the underground heat exchanger 1 is filled.
On the other hand, in Patent Document 3, a double pipe with fins is buried in the ground, a refrigerant circulation pump, a reservoir, and a heat exchanger are connected to the inner pipe of the double pipe in this order, and the heat pipe is connected to the outer pipe. A geothermal heat-use air conditioner that connects an exchanger and encloses and circulates refrigerant in these circulation systems is described. This will be briefly described with reference to FIG. 1a is a double pipe with fins embedded in the ground, 2 is a circulation pump, 3 is a heat exchanger, 4 is a blower, and 8a is a refrigerant reservoir. The refrigerant sent to the inner pipe of the double pipe 1a by the circulation pump 2 returns to the heat exchanger 3 on the ground while exchanging heat with the surrounding ground around the outer pipe. It is exchanged and air-conditioned, liquefied by the reservoir 8a, and sent to the double pipe 1a by the circulation pump 2 again.

In addition, some geothermal heat utilization systems that dig two wells instead of the conventional underground heat exchanger, use one as a pumping well for collecting ground heat and the other as a return water reduction well. Has been implemented in.
By the way, in these underground heat utilization systems that have been proposed in the past, the underground piping that performs heat exchange with the ground is not specified as simply “embed the underground pipe”, or Some of them used the internal space of the foundation piles, and other wells were excavated separately, but all of them were expensive and could not be applied to already completed buildings. . In the method of excavating wells separately, there is a problem of lowering the groundwater level in the pumping well, and there is a problem of surrounding soil contamination in the reduction well.

In order to embed pipes in the lower part of an existing structure, a vertical shaft is generally provided at both ends of the pipe, and pipes are laid in the horizontal direction by horizontal boring, propulsion method, etc. There are various problems such as a huge construction cost and obstacles in the surrounding traffic.
However, in recent years, a non-cutting boring machine equipped with a flexible connecting rod has been developed in the United States, and boring in an arbitrary shape, for example, an arc shape, is possible without providing a shaft. An example of such a boring machine and a construction method using the boring machine are described in Patent Document 4.

This boring machine is equipped with a specially shaped excavation head whose tip is cut obliquely with respect to the shaft, and if this is advanced while rotating, linear drilling is performed. When it moves forward without making it, the surface cut diagonally receives earth pressure, so it has the feature of moving in the diagonal direction. FIG. 6 is a conceptual diagram in the case of drilling directly under an existing structure S using the excavator 60, 50 is an excavation head, 51 is a flexible connecting rod, 65 is a clamp of the excavator 60, 66 Is also a chuck. FIG. 7 is an external view of the excavator 60, in which 61 is a forward frame, 62 is a rotation motor, 63 is a chain, 64 is a forward motor, P is a tubular body for excavation, and M is a lubricant. It is a chemical tank. The advancing frame 61 is provided with the clamp 65 and the chuck 66, and when the clamp 65 is advanced while the rotation of the tube P is restrained, the digging head 50 at the tip is directed obliquely and can be rotated by the chuck 66. When held and advanced, the excavation head 50 at the tip advances straight.
JP 2003-343848 A JP 2005-48972 A Japanese Utility Model Publication No. 60-113460 Japanese Patent Publication No. 61-257501

  The present invention realizes a ground heat utilization system using underground piping that does not require construction that is constrained by the construction site such as installation of a vertical shaft or excavation of a well, and that can also be constructed in the lower part of an existing building. With the goal.

The present invention is a geothermal heat utilization system in which an arc-shaped pipe is buried in the ground by such a boring machine.
That is, the present invention circulates a liquid between the underground pipe buried in the ground and the heat exchanger on the ground, and uses the heat obtained from the heat exchanger to cool and heat the air-conditioned space in the building. In the use air conditioning system, the underground pipe enters the ground obliquely from the outside of the building site , turns horizontally when it reaches the constant temperature layer at the bottom of the building, and then reaches the ground when it passes through the bottom of the building. and underground piping buried geothermal heat air conditioning systems, or in the ground is characterized in that laid in bent boring without pit rises obliquely towards ground of the expansion valve, heat exchanger In the geothermal heat-conditioning air conditioning system in which the air-conditioning space in the building is cooled and heated by the heat obtained from the heat exchanger by connecting the heat exchanger, the compressor, and the four-way valve in a switchable manner, the underground pipe , oblique direction from the outside of the building site Turned horizontally enter in the ground where it reached a constant temperature bath at the bottom of the building, that where passing through the lower part of the building in which laid at the bending boring without pit rises obliquely towards the ground This is an air conditioning system using geothermal heat.

  According to the present invention, an economical air-conditioning system that uses geothermal heat can be easily adopted even in existing buildings and the like, and there is an excellent effect that energy saving and cost reduction are realized.

  The present invention heats underground piping that enters the ground from the outside of the building site and is laid in a free shape in the lower part of the building, for example, underground piping that is laid in a substantially arc shape across the lower part of the building. This is an air conditioning system using geothermal heat as an exchanger. Such underground piping can be realized by boring using the above-described special excavation head and a flexible connecting rod. In other words, boring from the outside of the building site in an oblique direction, when the depth reaches the constant temperature layer, the boring direction is turned horizontally, and after passing through the lower part of the building, the boring direction is made obliquely toward the ground again, and the boring is performed in a substantially arc shape. Can be done. Thus, it may be a substantially arc shape by a diagonal-horizontal-diagonal combination, or may be bored in an arc shape with a constant curvature from beginning to end. In order to increase the heat transfer area, piping may be laid in an S shape or a spiral in the lower part of the building. In short, it is a bent boring without a shaft, and it is only necessary to embed the pipe body in the thermostatic layer at the bottom of the building.

The flexible rod used for excavation may be left in the ground as a tubular body and used for piping as it is, or after penetrating, a new tubular body is connected to the excavation head and pulled back, and this new tubular body is underground. You may lay it on.
According to this construction method, it is not only economical because there is no need to provide a shaft, but it is a great advantage that it can be applied to an existing building.

A first embodiment of the present invention will be described with reference to FIG. This figure is a block diagram of the air conditioning system of the first embodiment, and each symbol is the same as the description so far. 1 is an underground pipe, 2 is a circulation pump, 3 is a heat exchanger, 4 is a blower, 7 Is a circulation tank, and R is an air-conditioned space.
That is, a liquid is circulated between the underground pipe 1 buried in the ground (of course in the constant temperature layer) and the heat exchanger 3 on the ground, and the heat obtained from the heat exchanger 3 causes the inside of the building to circulate. An underground air-conditioning system for cooling and heating an air-conditioned space R, wherein the underground pipe 1 enters the ground from the outside of the building site and is laid in a substantially arc shape across the lower part of the building. ing. As the pipe body of the underground pipe, a metal pipe, a resin pipe or the like having good strength and heat conduction is preferable. In addition to a normal cylindrical shape, the tube body is more suitable to have a large surface area so that sufficient heat exchange can be performed, such as a finned tube or a star-shaped cross section. In some cases, a double tube as described in FIG. 5 may be used.

  In addition, as a liquid circulated through a series of pipes connecting the underground pipe 1 and the heat exchanger 3, for example, water or a chemical solution having excellent fluidity and low specific heat is preferable. Since the liquid at the underground temperature in the ground flows into the heat exchanger 3 through the underground pipe 1, if heat exchange is promoted by the blower 4, it is about 15 ° C, which is much lower than room temperature in summer. Cold air blows out, and in the winter season, hot air of about 15 ° C, which is higher than the outside air and close to the target temperature, blows out. However, since only a liquid having a temperature substantially equal to the underground temperature is circulated, air conditioning at high or low temperatures exceeding this temperature cannot be realized.

A second embodiment of the present invention will be described with reference to FIG. This figure is a block diagram of the air conditioning system of the second embodiment, where each reference numeral is the same as the description so far, 5 is a compressor, 6 is a four-way valve for switching the pipeline, 9 is an expansion valve, and 11 is a refrigerant. Piping.
In this embodiment, the underground pipe 1 buried in the ground and the expansion valve 9, the heat exchanger 3, the compressor 5, and the four-way valve 7 on the ground are connected so as to be able to be switched, so that freon, ammonia, carbon dioxide is contained therein. A refrigerant such as calcium chloride or the like (including so-called “brine”) is circulated, and the air-conditioned space R in the building is cooled and heated by the cold or hot heat obtained from the heat exchanger 3. Since the operation cycle of the so-called heat pump is performed using the refrigerant, it is necessary to switch the circulation direction of the refrigerant by the four-way valve 7 during the cooling operation and the heating operation. In FIG. 2, the arrow a is during cooling operation, and the arrow b is during heating operation. Since a refrigerant is used as the liquid to be circulated and the vaporized refrigerant is compressed to a high pressure by a compressor, an arbitrary temperature that is not directly influenced by the underground temperature can be realized, and it can be adopted not only for air conditioning in a building but also for a freezer.

  Even in this embodiment, the underground pipe enters the ground from the outside of the building site and is laid in a substantially arc shape across the lower part of the building. However, as described above, the shape of the pipe is necessary. Other than this, it can be arbitrarily selected.

It is a block diagram of the air-conditioning system using geothermal heat in the first embodiment of the present invention. It is a block diagram of the air-conditioning system using geothermal heat in the 2nd Example of this invention. It is a block diagram of the air conditioning system of geothermal heat utilization in the prior art. It is a block diagram of the air-conditioning system of underground heat utilization in another conventional technique. It is a lineblock diagram of an air-conditioning system using geothermal heat in other conventional technology. It is a conceptual diagram of the curved boring method in a prior art. It is an external view of the excavation machine in the boring method of FIG.

Explanation of symbols

1 Underground piping (Ground heat exchanger)
1a Double pipe 2 Circulation pump 3 Heat exchanger 4 Blower 5 Compressor 6 Four-way valve 7 Circulation tank 8 Condenser
8a Reservoir 9 Expansion valve 10 Evaporator 11 Refrigerant pipe 50 Digging head 51 Connecting rod 60 Digging machine 61 Forwarding frame 62 Rotating motor 63 Chain 64 Forwarding motor 65 Clamp 66 Chuck M Chemical liquid tank P Pipe body R Air-conditioned space S Structure

Claims (2)

In the underground heat utilization air conditioning system that circulates a liquid between the underground pipe buried in the ground and the ground heat exchanger, and heats and cools the air-conditioned space in the building by the heat obtained from the heat exchanger, Underground piping enters the ground diagonally from the outside of the building site , turns horizontally when it reaches the thermostatic layer at the bottom of the building, and rises diagonally toward the ground when it passes through the bottom of the building An underground air-conditioning air-conditioning system that is laid with bent boring without vertical shafts . Underground piping buried in the ground and expansion valves, heat exchangers, compressors, and four-way valves on the ground are switchably connected to circulate the refrigerant, and the air to be air-conditioned in the building by the heat obtained from the heat exchangers In the geothermal air conditioning system that heats and cools the space, the underground pipe enters the ground obliquely from the outside of the building site and turns horizontally when it reaches the constant temperature layer at the bottom of the building. An underground air-conditioning air-conditioning system that is laid with bent boring without a shaft that rises in an oblique direction toward the ground when passing through the ground.

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