JP2020176745A - Geo hybrid system - Google Patents

Abstract

To provide an underground heat utilization system capable of combining the advantages of an open-loop system and a closed-loop system while solving the drawbacks of them.SOLUTION: An underground well 1 is provided in an aquifer. A pumping pipe 3 for pumping groundwater from the underground well 1 passes through a heat exchanger 11 and is connected to one port of a motor valve 5. To the other port of the motor valve 5, a return pipe 6 that returns to the underground well 1 via the heat exchanger 11 and the ground is connected. To the other port, a branch pipe 12 communicating with a water tank 14 is connected. A refrigerant circulation pipe 8 that supplies heat to a heat pump 16 is configured to exchange heat with the pumping pipe 3 and the return pipe 6 in the heat exchanger 11. In addition, switching the motor valve 5 to the return pipe 6 or the branch pipe 12 is automatically performed by a control device 15 based on the water level of the underground well 1 and then the heat load of the heat pump 16.SELECTED DRAWING: Figure 1

Description

The present invention relates to a geothermal heat utilization system, and more particularly to a geothermal heat utilization system capable of having advantages of each other while solving the drawbacks of the open loop method and the closed loop method.

The geothermal heat pump system cools the room by exhausting the heat collected from the room to the ground in the summer, and conversely exhausts the heat collected from the ground into the room in the winter. It can be applied to an indoor heating / cooling air conditioning system that heats a room.

Further, since the geothermal heat utilization heat pump system does not exhaust heat to the atmosphere unlike a normal air heat source heat pump system, it is expected to have an effect of suppressing the heat island phenomenon. In addition, since it uses geothermal heat as a heat source and does not use fossil fuels, it is expected to have a carbon dioxide reduction effect. As described above, the geothermal heat pump system is a geothermal heat utilization system that is attracting attention for its effective utilization due to the recent rise in crude oil prices and consideration for environmental conservation on a global scale.

The geothermal heat utilization system is a closed loop method in which antifreeze liquid (heat medium) circulates in the circulation pipe and exchanges heat with load equipment such as a heat pump, and ground water (heat medium) is pumped from a pumping well. It can be roughly divided into an open loop method in which heat is exchanged with a load device such as a heat pump while returning to a reduction well or the like.

The open loop method can be broadly divided into a reduction type that returns the pumped groundwater to the aquifer and a discharge type that discharges the pumped groundwater to public water areas such as rivers using underground drainage ditches. .. The reduction type can be further subdivided into a reduction well type in which groundwater is returned to the reduction well and a infiltration well type in which groundwater is infiltrated into the ground using an infiltration basin or a infiltration pond.

Since the open loop method draws up groundwater and uses it as a heat medium (heat source water), there is a risk of causing land subsidence due to excessive pumping of groundwater. In the open loop method, the groundwater pumped from the pumping well is to be returned to the reduction well after heat exchange, but in reality, the groundwater is discharged to the underground drainage ditch without returning to the reduction well. .. Therefore, if the pumping well, which is the water source, contains harmful substances such as lead and arsenic, there is a risk of polluting the water quality of rivers and the like. Therefore, it is necessary to comply with the laws and regulations related to the use of groundwater such as pumping regulations in the national and local governments, and pay attention to the use of groundwater in the surrounding area and the impact on the quality of the discharge destination water.

On the other hand, the closed loop method can be roughly divided into a vertically buried type in which the circulation pipe is buried perpendicular to the ground and a horizontally buried type in which the circulation pipe is buried horizontally. The vertical burial type uses a borehole method in which a circulation pipe is buried using a drilling hole in the boring, and a steel pipe pile placed in a hard rock layer for the purpose of stabilizing the foundation of the building. It can be subdivided into a foundation pile method in which a circulation pipe is buried inside a steel pipe pile.

In the closed loop method, heat is exchanged between the ground and the heat medium in the pipe via the circulation pipe, so that the amount of heat extracted and exhausted depends on the length of the circulation pipe. Therefore, it is necessary to carry out a thermal response test (thermal response test) to confirm the thermal conductivity between the underground and the circulation pipe in advance.

Japanese Unexamined Patent Publication No. 2018-14506 JP-A-2015-113992 Japanese Unexamined Patent Publication No. 2018-071949

As mentioned above, the open-loop geothermal heat utilization system pumps groundwater from the aquifer, and excessive pumping of groundwater may cause land subsidence. Therefore, the installation location is regulated by pumping water. Limited to areas with abundant water sources. Therefore, there is a problem that the open loop method is not widely used in urban areas where pumping water is regulated.

In addition, the open-loop geothermal heat utilization system may pollute the water quality of public water areas such as rivers when the pumping wells that pump up groundwater contain harmful substances such as lead and arsenic.

On the other hand, in the closed loop method, the heat medium flowing in the circulation pipe does not flow out to the outside, so there are problems of land subsidence due to excessive pumping of groundwater and water pollution in public water bodies such as rivers, which are seen in the open loop method. Will never happen.

However, the amount of heat collected and exhausted by the heat medium from the ground through the circulation pipe or exhausted to the ground depends on the length of the circulation pipe. Therefore, it is necessary to secure a sufficient pipe length for heat exchange with the ground. For example, a large-scale underground where pipes are wound multiple times and laid along the horizontal or vertical direction. A heat exchanger (heat exchange well) will have to be installed. Therefore, there is a problem that a large amount of cost and a large installation space are required for the installation of the geothermal heat exchanger.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is geothermal heat that can have advantages of each other while solving the drawbacks of the open loop method and the closed loop method. It is to provide a utilization system.

The underground heat utilization system according to the present invention for achieving the above object is a first pipe system (3, 6) in which ground water flows inside while being installed in the ground, and the first pipe system (3, 6). A first pump (2) connected to, a load device (16) that uses underground heat, and a second pipe system in which a heat medium circulates inside while supplying underground heat to the load device (16). Heat exchange between (8), the second pump (9) connected to the second pipe system (8), and the first pipe system (3, 6) and the second pipe system (8). This is an underground heat utilization system provided with a heat exchange unit (11) for performing the above, and the first pipe system (3, 6) has a well (1) or a pumping well whose water source is ground water as a starting point. The groundwater that has passed through the heat exchange section (11) and the ground and is laid so as to return to the well (1) or the pumping well and flows through the first pipe system (3, 6) is the first. It is characterized in that water is pumped from the well (1) or the pumping well by a pump (2), circulates through the first pipe system (3, 6), and discharged to the well (1) or the pumping well.

In the above configuration, the groundwater flowing through the first pipe system (3, 6) is directly returned to the well (1) every time it goes around (circulates) around the first pipe system (3, 6), and is returned directly to the well (1). ) Will be replaced with new groundwater. The well (1) using groundwater as a water source functions as a stable heat source in which the temperature having a large heat capacity is close to the temperature in the ground. The groundwater that has exchanged heat with the ground while making one round of the first pump system (3, 6) will directly exchange heat with the well (1), which is its stable heat source. As a result, in the first pump system (3, 6), heat exchange is performed not only in the geothermal heat exchanger but also in the well (1), so that the pipe length can be shorter than that of the conventional closed loop. That is, unlike the conventional closed loop, the first pipe system (3, 6), which is a closed loop, can reduce the scale of the underground heat exchanger installed in the ground.

The second feature of the geothermal heat utilization system according to the present invention is that the first pipe system (3, 6) communicates with the water storage tank (14) on the downstream side from the heat exchange unit (11). It is laid so that it can communicate with the system (12).

With the above configuration, it is possible to supply geothermal heat to the load device (16) while discharging the groundwater pumped from the well (1) in one direction via the third pipe system (12). That is, the groundwater heat exchange method can be switched from the closed loop method to the open loop method or from the open loop method to the closed loop method.

The third feature of the geothermal heat utilization system according to the present invention is that the first pipe system (3, 6) has an opening degree with respect to the third pipe system (12) within a range of 0 to 100 [%]. It is communicated with the third pipe system (12) by the settable direction switching means (5).

In the above configuration, the heat exchange method of groundwater can be switched between the closed loop method, the open loop method, and the closed / open combined method.

A fourth feature of the geothermal heat utilization system according to the present invention is a water level sensor (4) for measuring the water level of the well (1) and a control device (15) for controlling the direction switching means (5). The control device (15) determines the opening degree of the direction switching means (5) with respect to the third pipe system (12) based on the measurement signal transmitted from the water level sensor (4).

In the above configuration, one optimum heat exchange method is timely selected from the closed loop method, the open loop method, and the closed / open combined method according to the water level of the well (1).

The fifth feature of the underground heat utilization system according to the present invention is the first flow rate sensor (7) for measuring the flow rate of the ground water flowing through the first pipe system (3, 6) and the second pipe system (the second pipe system). A second flow rate sensor (10) for measuring the flow rate of the heat medium flowing through 8) and a third flow rate sensor (13) for measuring the flow rate of the groundwater flowing through the third pipe system (12) are provided. The control device (15) determines the opening degree of the direction switching means (5) with respect to the third pipe system (12) based on the measurement signals transmitted from the flow rate sensors (7, 10, 13). That is.

In the above configuration, considering the thermal load of the load device (16) in addition to the water level of the well (1), one of the most suitable heat exchanges is the closed loop method, the open loop method, or the closed / open combined method. The method will be selected in a timely manner. This prevents ground subsidence due to excessive pumping of groundwater, and enables stable heat supply with a reasonably small amount of pumping.

The sixth feature of the geothermal heat utilization system according to the present invention is the second pump (9), the heat exchange unit (11), the direction switching means (5), the control device (15), and the first. All or part of the flow rate sensor (7), the second flow rate sensor (10), and the third flow rate sensor (13) are assembled and configured inside a common ground facility (18). is there.

In the above configuration, the control system and the heat exchange unit are unitized as ground equipment. As a result, geothermal heat can be supplied not only to new buildings but also to existing buildings. This makes it possible to reduce construction costs, save space, shorten construction schedules, and so on.

The seventh feature of the geothermal heat utilization system according to the present invention is that the groundwater discharged from the third pipe system (12) to the water storage tank (14) is used as domestic water or disaster prevention water. is there.

With the above configuration, it is possible to save water charges and preferably prevent the water tank from becoming large by effectively using the heat-exchanged groundwater as miscellaneous water for daily life and disaster prevention.

According to the geothermal heat utilization system of the present invention, it is possible to have the advantages of each other while solving the drawbacks of the open loop method and the closed loop method.

It is explanatory drawing which shows the hybrid type geothermal heat utilization system which concerns on one Embodiment of this invention. It is explanatory drawing which shows the control system of the hybrid type geothermal heat utilization system. It is explanatory drawing which shows the hybrid type heat utilization system which operates in a closed loop system. It is explanatory drawing which shows the hybrid type heat utilization system which operates by an open loop system. It is explanatory drawing which shows the hybrid type heat utilization system which operates by the closed open combination system. It is explanatory drawing which shows the opening degree of the electric valve which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram showing a hybrid type geothermal heat utilization system 100 according to an embodiment of the present invention.

In this hybrid type geothermal heat utilization system 100, the groundwater flowing through the water zone is collected by the underground well 1, and the collected groundwater is collected by either a closed loop method, an open loop method, or a closed / open combined method. By exchanging heat with the refrigerant circulation pipe 8 of the heat exchange target device (for example, heat pump 16) while selectively flowing in the pipe system, the geothermal heat contained in the groundwater is transferred to public facilities (for example, nursery school, elderly people). It is used as a heat source for air conditioning equipment or hot water supply equipment of small public facilities such as facilities and district public halls, preferably small public facilities that can also be used as disaster prevention bases and evacuation sites in the event of a disaster.

The "closed loop type pipe system" referred to here is a pipe system in which a pumping pipe 3 and a return pipe 6 communicate with each other via an electric valve 5. Further, the "open loop type pipe system" is a pipe system in which the pumping pipe 3 and the branch pipe 12 are connected via an electric valve 5. Further, the "closed / open combined type pipe system" is a pipe system in which the pumping pipe 3 communicates with both the return pipe 6 and the branch pipe 12 via the electric valve 5.

In addition, when switching between closed-loop, open-loop, or closed-open combined pipe systems, the highest priority check item is that the water level in the underground well 1 is at a predetermined stable water level, and the equipment subject to heat exchange (heat pump). It is configured to be performed automatically according to the heat load of 16).

Therefore, in this hybrid type geothermal heat utilization system 100, even when operating in the open loop system, ground subsidence due to excessive pumping of groundwater is not caused. Further, since the pumped groundwater is stored in the water tank 14 and effectively used as miscellaneous water for daily life and disaster prevention, it does not occur to deteriorate the water quality of the water area such as the underground drainage ditch.

In addition, in this hybrid type geothermal heat utilization system 100, the ground water pumped from the underground well 1 is returned to the underground well 1 after exchanging heat with the ground in the underground heat exchanger, and is underground. Heat exchange takes place directly in the well 1. As a result, the geothermal heat exchanger used in the hybrid geothermal heat utilization system 100 will be smaller than the conventional closed-loop geothermal heat exchanger. As a result, the installation cost and the installation space can be suitably reduced as compared with the conventional closed-loop type geothermal heat exchanger.

Regarding the configuration of the hybrid type underground heat utilization system 100, an underground well 1 for taking out groundwater from a submerged layer, a water well pump 2 for pumping groundwater to the ground, and a groundwater are transferred to a heat exchanger 11. The pumping pipe 3, the water level sensor 4 that measures the water level of the underground well 1, the electric valve 5 that switches the transfer direction of the groundwater, and the return pipe 6 that returns the groundwater to the underground well 1 via the heat exchanger 11 and the ground. A first flow sensor 7 that measures the flow rate of groundwater flowing through the return pipe 6, and a refrigerant circulation that collects underground heat from the groundwater flowing through the pumping pipe 3 or the return pipe 6 or exhausts indoor heat to the groundwater. A pipe 8, a circulation pump 9 for circulating a refrigerant, a second flow sensor 10 for measuring the flow rate of the refrigerant flowing through the refrigerant circulation pipe 8, groundwater flowing through the pumping pipe 3 or the return pipe 6, and a refrigerant flowing through the refrigerant circulation pipe 8. A heat exchanger 11 that exchanges heat between the two, a branch pipe 12 that transfers groundwater to a water storage tank, a third flow sensor 13 that measures the flow rate of groundwater flowing through the branch pipe 12, and a water storage that stores groundwater. The tank 14, the control device 15 that takes in the measurement signals of the water level sensor 4 and the flow sensors 7, 10 and 13 to control the water well pump 2, the electric valve 5 and the circulation pump 9, respectively, and heat or cold heat in the room. It is configured to include a heat pump 16 to supply. Hereinafter, each configuration will be further described.

The underground well 1 is composed of, for example, a casing pipe having an opening at one end, and a strainer portion having a slit or a through hole for allowing groundwater to enter the side portion. The underground well 1 is provided in the aquifer, and the groundwater flows into the casing pipe through the strainer portion. The aquifer is a stratum in which groundwater is stored. It usually means a porous permeable layer consisting of sand and gravel sandwiched between impermeable layers such as clay (a layer in which water does not easily flow).

The water well pump 2 is, for example, a turbo pump. A filter (not shown) is attached to the suction port to prevent sand, pebbles, etc. from entering. The water well pump 2 is installed in the groundwater inside the underground well 1, sucks the groundwater by the rotation of the impeller, attaches a predetermined head (head) to the sucked groundwater, and discharges it. The water well pump 2 is driven by a waterproof electric motor. The control of the water well pump 2 is automatically performed by the control device 15.

The water well pump 2 is a circulation pump that not only pumps groundwater from the underground well 1 to the ground via a pumping pipe 3 but also flows the pumped groundwater through the return pipe 6 at a predetermined flow rate and returns it to the underground well 1. Also works. Therefore, regarding the total head of the water well pump 2, the maximum height (actual lift) from the pump discharge port to the ground, the loss head when passing through the water well pump 2, the loss head when passing through the return pipe 6, And the lift including the speed head when discharging from the return pipe 6 is required.

When this hybrid type geothermal utilization system 100 is operated in a closed loop system, groundwater is collected by a water well pump 2 from underground well 1 → pumping pipe 3 → electric valve 5 → return pipe 6 → (horizontal system geothermal heat). It is circulated in the route of exchanger 6A, foundation pile type geothermal heat exchanger 6B, borehole type geothermal heat exchanger 6C) → underground well 1. On the other hand, when the hybrid type geothermal heat utilization system 100 is operated by the open loop method, the groundwater is routed by the water well pump 2 from the underground well 1 → the pumping pipe 3 → the electric valve 5 → the branch pipe 12 → the water tank 14. It is swept in one direction.

Further, when the hybrid type geothermal heat utilization system 100 is operated in a closed / open combined system, a part of the groundwater is flowed to the branch pipe 12 by the electric valve 5 by the water well pump 2, and the rest is returned. It is flushed through the pipe 6 and returned to the underground well 1.

The pumping pipe 3 is a flow path for flowing groundwater through a route of a water well pump 2 → a heat exchanger 11 → an electric valve 5, and is used in any of the closed loop method, the open loop method, and the closed / open combined method. It is a common pipe to be used. When the groundwater flowing through the pumping pipe 3 passes through the heat exchanger 11, heat exchange is performed with the refrigerant (heat medium) flowing through the refrigerant circulation pipe 8. As the material of the pump 3, high-density polyethylene (for example, PE100) having excellent durability, impact resistance, and chemical resistance can be used.

The water level sensor 4 is a sensor that constantly monitors the water level in the underground well 1 in order to prevent ground subsidence due to a decrease in the groundwater level. The measurement signal (measured value) output by the water level sensor is taken into the control device 15. When the measured value of the water level is likely to exceed a preset threshold value, the control device 15 drives the electric valve 5 to switch the open loop method to the closed loop method, or switches to the closed / open combined method.

The motorized valve 5 is a three-way valve that communicates the groundwater flowing through the pumping pipe 3 to either the return pipe 6 or the branch pipe 12, or to both the branch pipe 12 and the return pipe 6. When communicating with both the branch pipe 12 and the return pipe 6 (in the case of the closed / open combined method), when the opening degree with respect to the branch pipe 12 is X [%] (0 [%] <X <100 [%]). The opening degree with respect to the return pipe 6 is 100 [%] −X [%]. The opening degree of the motorized valve 5 is determined by the control device 15 according to the measured value of the water level sensor regarding the water level of the underground well 1 and the thermal load of the heat pump 16. Details will be described later with reference to FIG.

The return pipe 6 is a flow path of electric valve 5 → heat exchanger 11 → (horizontal type geothermal heat exchanger 6A, foundation pile type geothermal heat exchanger 6B, borehole type geothermal heat exchanger 6C) → underground well 1. It is used in the case of the closed loop method and the closed / open combined method. Therefore, the ground water flowing through the return pipe 6 exchanges heat with the refrigerant flowing through the refrigerant circulation pipe 14 in the heat exchanger 11, and then the horizontal type geothermal heat exchanger 6A and the foundation pile type geothermal heat exchanger 6B. , And a borehole type geothermal heat exchanger 6C exchanges heat with the ground and returns to the underground well 1. As the material of the return pipe 6, high-density polyethylene (for example, PE100) having excellent durability, impact resistance, and chemical resistance can be used.

The horizontal geothermal heat exchanger 6A is composed of coil-shaped pipes laid along the horizontal direction (for convenience of explanation, the pipes are laid along the vertical direction, but in reality, they are laid along the horizontal direction. It is laid.) The pipe shape of the horizontal geothermal heat exchanger 6A may be a shape that increases the contact area with the ground, and a meandering shape, a spiral shape, or the like can be adopted in addition to the coil shape. ..

The foundation pile type geothermal heat exchanger 6B is composed of U-shaped pipes laid along the vertical direction. The U-shaped pipe is buried inside the foundation pile for reinforcing the foundation of the building. The gap between the outer peripheral surface of the pipe and the inner peripheral surface of the foundation pile is filled with gravel, silica sand, etc. The pipe shape of the foundation pile type geothermal heat exchanger 6B may be a shape that increases the contact area with the ground, and a double U shape, a spiral shape, or the like may be adopted in addition to the U shape. It is possible.

The borehole type geothermal heat exchanger 6C is composed of U-shaped pipes laid deeper in the ground than the foundation pile type along the vertical direction. The pipe is buried in a borehole (excavation hole) formed by boring in the ground. The gap between the outer peripheral surface of the pipe and the bore hole is filled with gravel, silica sand, or the like. The pipe shape of the borehole type geothermal heat exchanger 6C may be a shape that increases the contact area with the ground, and a double U shape, a spiral shape, or the like can be adopted in addition to the U shape. Is.

The first flow rate sensor 7 may be any as long as the measured value of the flow rate is output as an electric signal, and the measurement method is not particularly limited. The same applies to the second flow rate sensor 10 and the third flow rate sensor 13.

The refrigerant circulation pipe 8 is a sealed circulation pipe in which the refrigerant circulates between the heat pump 16 and the heat exchanger 11. Therefore, the geothermal heat (heat of groundwater) is supplied to the heat pump 16 through the refrigerant circulation pipe 8, and the heat in the room is exhausted to the groundwater.

The circulation pump 9 is a pump that circulates a refrigerant (heat medium) along a refrigerant circulation pipe 8. The control of the circulation pump 9 is automatically performed by the control device 15 according to the measured value of the water level sensor regarding the water level of the underground well 1 and the thermal load of the heat pump 16.

In the open loop system, the heat exchanger 11 exchanges heat between the refrigerant circulation pipe 8 and the pumping pipe 3. In the closed loop method and the closed / open combined method, heat exchange is performed between the refrigerant circulation pipe 8, the pumping pipe 3, and the return pipe 6, respectively.

The branch pipe 12 is a flow path from the motorized valve 5 to the water storage tank 14, and is used in the case of the open loop method and the closed / open combined method. As the material of the branch pipe 12, high-density polyethylene (for example, PE100) having excellent durability, impact resistance, and chemical resistance can be used.

The water storage tank 14 is a tank in which the groundwater pumped from the underground well 1 by the water well pump 2 is stored. The groundwater stored in the water tank 14 is used as daily / disaster prevention miscellaneous water (toilet, watering, bath, etc.). In use, harmful substances are removed by passing through, for example, a filtration device (not shown), a sterilizer (not shown), an ion exchange device (not shown), and a purification device (not shown). It has become so.

The control device 15 receives measurement signals from the water level sensor 4, the first flow sensor 7, the second flow sensor 10, and the third flow sensor 13, and controls the water well pump 2, the electric valve 5, and the circulation pump 9. Is being sent.

The heat pump 16 has a compressor (not shown), a condenser (not shown), an expansion valve (not shown), an evaporator (not shown), a fan (not shown), and a refrigerant through which the refrigerant flows. It is composed of a circulation pipe (not shown). When the heat pump 16 heats the room, the refrigerant is compressed by a compressor and liquefied, so that the heat radiated when the refrigerant is liquefied warms the air in the room and blows the warmed air by a fan.

On the other hand, when the heat pump 16 cools the room, the refrigerant is expanded by the expansion valve and vaporized in the evaporator, and when the refrigerant vaporizes, the heat in the room is collected to cool the air in the room and the cooled air. Is blown by a fan.

The small-scale facility 17 is, for example, a nursery school, a facility for the elderly, and a public hall (disaster prevention base, evacuation center in the event of a disaster).

The building 18 unitizes an electric valve 5, a circulation pump 9, a heat exchanger 11, a control device 15, a first flow rate sensor 7, a second flow rate sensor 10, and a third flow rate sensor 13. The building 18 has interfaces for the pumping pipe 3, the return pipe 6, the refrigerant circulation pipe 8, and the branch pipe 12.

FIG. 2 is an explanatory diagram showing a control system of the hybrid heat utilization system 100.
The control device 15 takes in the measurement signals of the water level sensor 4 and the measurement signals of the first flow sensor 7, the second flow sensor 10 and the third flow sensor 13, and takes in the water well pump 2, the electric valve 5, and the circulation pump 9. And the heat pump 16 are controlled respectively.

The water level sensor 4 constantly measures the water level of the underground well 1. Further, the first flow rate sensor 7 constantly measures the flow rate of groundwater flowing through the return pump 6. The second flow rate sensor 10 constantly measures the flow rate of the refrigerant flowing through the refrigerant circulation pipe 8. The second flow rate sensor 13 constantly measures the flow rate of groundwater flowing through the branch pipe 12.

The motorized valve 5 includes a pumping pipe port 51a to which the pumping pipe 3 is connected, a return pipe port 51b to which the return pipe 6 is connected, and a branch pipe port 51c to which the branch pipe 12 is connected. It is composed of a seat 51, a valve body 52 having an opening 52a for communicating each port, and a slide mechanism 53 for moving the valve body 52 in the longitudinal direction (axial direction). The slide mechanism 53 includes an encoder (not shown), and the measurement signal of the encoder is taken into the control device 15. Therefore, the opening degree of the valve body 52 with respect to the branch pipe 12 is detected by the control device 15 via the measurement signal of the encoder.

The pumping pipe 3 depends on the ratio of the overlapping length X of the opening 52a of the valve body 52 and the port 51b for the return pipe to the overlapping length Y of the opening 52a of the valve body 52 and the port 51c for the branch pipe. The groundwater flowing through the pipe is distributed to the return pipe 6 and the branch pipe 12. Therefore, the opening degree of the motorized valve 5 with respect to the branch pipe 12 is defined by Y / (X + Y) × 100 [%]. That is, when the opening degree with respect to the branch pipe 12 is 0 [%], all the groundwater is underground well 1 → water well pump 2 → pumping pipe 3 → electric valve 5 → return pipe 6 → (horizontal underground heat exchanger 6A). , Foundation pile type underground heat exchanger 6B, borehole type underground heat exchanger 6C) → It is returned to the underground well 1 in a closed loop of underground well 1.

On the other hand, when the opening degree with respect to the branch pipe 12 is 100 [%], all the groundwater is stored in an open loop of underground well 1 → water well pump 2 → pumping pipe 3 → electric valve 5 → branch pipe 12 → water storage tank 14. It is released to 14. When the opening degree with respect to the branch pipe 12 is 50 [%], half of the pumped groundwater is returned to the underground well 1 in a closed loop, and the other half is discharged to the water tank 14 in an open loop.

The control device 15 determines the opening degree of the electric valve 5 with respect to the branch pipe 12 according to the water level of the underground well 1 and the thermal load of the heat pump 16. The thermal load of the heat pump 16 can be detected, for example, from the flow rate of the refrigerant flowing through the refrigerant circulation pipe 8 (measurement signal of the second flow rate sensor 10), the temperature of the refrigerant (upstream side and downstream side of the heat pump 16), and the like. it can.

FIG. 3 is an explanatory diagram showing a hybrid heat utilization system 100 operating in a closed loop system. The opening degree of the motor-operated valve 5 when the hybrid heat utilization system 100 is operating in a closed loop is 0 [%] (FIG. 6A). Further, it is assumed that the heat pump 16 is operated by heating. The same applies thereafter.

The groundwater containing the geothermal heat is pumped and pumped by the water well pump 2, and the geothermal heat is exhausted to the refrigerant circulation pipe 8 in the heat exchanger 11 while flowing through the pumping pipe 3. After the exhausted groundwater passes through the electric valve 5, the underground heat is exhausted to the refrigerant circulation pipe 8 again in the heat exchanger 11 while flowing through the return pipe 6.

The underground water exhausted from the underground heat to the refrigerant (refrigerator circulation pipe 8) in the heat exchanger 11 is a horizontal type geothermal heat exchanger 6A, a foundation pile type geothermal heat exchanger 6B, and a borehole type geothermal heat exchanger. After collecting geothermal heat from the ground when passing through 6C, it is returned to the underground well 1.

The refrigerant that has collected the geothermal heat from the ground water in the heat exchanger 11 is transferred to the heat pump 16 by the circulation pump 9, compressed by the compressor, dissipates the geothermal heat, and is liquefied. The radiated geothermal heat is supplied indoors by a blower such as a fan. The refrigerant that has dissipated the geothermal heat is transferred to the heat exchanger 11 by the circulation pump 9, heat is exchanged again between the pumping pipe 3 and the return pipe 6, and the geothermal heat is collected from the ground water. After that, the refrigerant repeats the above operation.

FIG. 4 is an explanatory diagram showing a hybrid heat utilization system 100 operating in an open loop system. The opening degree of the motor-operated valve 5 when the hybrid heat utilization system 100 is operating in an open loop is 100 [%] (FIG. 6 (b)).

The groundwater containing the geothermal heat is pumped and pumped by the water well pump 2, and the geothermal heat is exhausted to the refrigerant circulation pipe 8 in the heat exchanger 11 while flowing through the pumping pipe 3. After passing through the motorized valve 5, the exhausted groundwater flows through the branch pipe 12 and is discharged to the water storage tank 14 for daily / disaster prevention miscellaneous water (toilet, watering, bath, etc.).

The refrigerant that has collected the geothermal heat from the ground water in the heat exchanger 11 is transferred to the heat pump 16 by the circulation pump 9, compressed by the compressor, dissipates the geothermal heat, and is liquefied. The radiated geothermal heat is supplied indoors by a blower such as a fan. The refrigerant that has dissipated the geothermal heat is transferred to the heat exchanger 11 by the circulation pump 9, and the heat is exchanged again between the pumping pipe 3 and the return pipe 6 to collect the geothermal heat from the ground water. The refrigerant that collects geothermal heat repeats the same operation.

FIG. 5 is an explanatory diagram showing a hybrid heat utilization system 100 operating in a closed / open combined system. The opening degree of the electric valve 5 when the hybrid heat utilization system 100 is operated in a closed / open combined system is determined by the control device 15 based on the water level of the underground well 1, the thermal load of the heat pump 16, and the like. .. Here, as an example, the opening degree of the motor-operated valve 5 is set to 50 [%] (FIG. 6 (c)).

The groundwater containing the geothermal heat is pumped and pumped by the water well pump 2, and the geothermal heat is exhausted to the refrigerant circulation pipe 8 in the heat exchanger 11 while flowing through the pumping pipe 3. Half of the exhausted groundwater flows through the return pipe 6 and the other half flows through the branch pipe 12 in the motorized valve 5.

The groundwater flowing through the return pipe 6 exhausts the geothermal heat to the refrigerant circulation pipe 8 again in the heat exchanger 11 on the way. The exhausted ground water is collected after collecting underground heat from the ground when passing through the horizontal type geothermal heat exchanger 6A, the foundation pile type underground heat exchanger 6B, and the borehole type geothermal heat exchanger 6C. , Returned to underground well 1.

On the other hand, the groundwater flowing through the branch pipe 12 is discharged to the water storage tank 14 and used as daily / disaster prevention miscellaneous water (toilet, watering, bath, etc.).

The refrigerant that has collected the geothermal heat from the ground water in the heat exchanger 11 is transferred to the heat pump 16 by the circulation pump 9, compressed by the compressor, dissipates the geothermal heat, and is liquefied. The radiated geothermal heat is supplied indoors by a blower such as a fan. The refrigerant that has dissipated the geothermal heat is transferred to the heat exchanger 11 by the circulation pump 9, and the heat is exchanged again between the pumping pipe 3 and the return pipe 6 to collect the geothermal heat from the ground water. The refrigerant that collects geothermal heat repeats the same operation.

As described above, according to the hybrid heat utilization system 100 of the present invention, the system of the pumping pipe 3 and the return pipe 6 starts from the underground well 1 whose water source is underground water, passes through the heat exchanger 11 and the ground. The underground water that is laid so as to return to the underground well 1 and flows through the pumping pipe 3 and the return pipe 6 is pumped from the underground well 1 by the water well pump 2, flows through the pumping pipe 3 and the return pipe 6, and flows through the underground well 1. It is configured to be discharged to.

Since the groundwater in the underground well 1 has a large heat capacity, its temperature is close to the underground temperature and is stable. Since the heat-exchanged groundwater is directly returned to the underground well 1, the required amount of heat collected and exhausted (heat exchange amount) in the ground is smaller than that of the conventional closed loop. As a result, the scale of the heat exchangers installed in the ground (horizontal type geothermal heat exchanger 6A, foundation pile type geothermal heat exchanger 6B, borehole type geothermal heat exchanger 6C) should be reduced and downsized. Is possible. This makes it possible to reduce the cost and space for installing the geothermal heat exchanger.

The system of the pumping pipe 3 and the return pipe 6 is laid on the downstream side of the heat exchanger 11 so as to communicate with the branch pipe 12 communicating with the water storage tank 14 via the electric valve 5. The motorized valve 5 can automatically set the opening degree with respect to the branch pipe 12 within the range of 0 to 100 [%]. As a result, the groundwater pumped from the underground well 1 is stored in the water storage tank 14 and is not returned to the reduction well or the like in the ground. As a result, water pollution in the water area due to harmful substances contained in groundwater does not occur.

Further, the opening degree of the electric valve 5 with respect to the branch pipe 12 is determined by the control device 15 based on the water level of the underground well 1. This prevents land subsidence due to excessive pumping of groundwater.

Further, the opening degree of the motorized valve 5 with respect to the branch pipe 12 is determined by the control device 15 in consideration of the thermal load of the heat pump 16 in addition to the water level of the underground well 1. This makes it possible to efficiently supply geothermal heat with a small amount of pumped water.

Further, since the groundwater discharged into the water tank 14 is sterilized, filtered, and purified, it is effectively used as water for daily life or disaster prevention in an emergency.

As described above, the hybrid heat utilization system 100 of the present invention solves the problems of ground subsidence due to excessive pumping of groundwater and water pollution of public water areas due to harmful substances contained in groundwater, which are seen in the conventional open loop method. In addition to solving the problem, it is possible to solve the problems of an increase in installation cost and an increase in installation space due to an increase in the size of the geothermal heat exchanger, which is seen in the conventional closed loop method.

Further, the hybrid heat utilization system 100 of the present invention appropriately selects the optimum method from the closed loop method, the open loop method, and the closed / open combined method based on the water level of the underground well 1 and the thermal load of the heat pump 16. Since it can be selected, it is possible to efficiently supply underground heat with a small amount of pumping water.

Therefore, according to the hybrid heat utilization system 100 of the present invention, it is possible to have advantages of each other while solving the drawbacks of the open loop method and the closed loop method. Even in urban areas where there are restrictions on the pumping of groundwater, geothermal heat can be used in an open-loop system.

As for the groundwater, the groundwater may be pumped from the pumping well instead of the underground well 1. In this case, the pump for pumping water can be installed in the building 18.

1 Underground well 2 Water well pump 3 Pumping pipe 4 Water level sensor 5 Electric valve 6 Return pipe 7 1st flow sensor 8 Coolant circulation pipe 9 Circulation pump 10 2nd flow sensor 11 Heat exchanger 12 Branch pipe 13 3rd flow sensor 14 Water storage Tank 15 Control device 16 Heat pump 17 Small facility 18 Building 100 Hybrid type underground heat utilization system

Claims (7)

The first pipe system (3, 6) where groundwater flows inside while being installed underground,
The first pump (2) connected to the first pipe system (3, 6) and
Load equipment (16) that uses geothermal heat,
A second pipe system (8) in which a heat medium circulates inside while supplying geothermal heat to the load device (16).
The second pump (9) connected to the second pipe system (8) and
A geothermal heat utilization system including a heat exchange unit (11) for exchanging heat between the first pipe system (3, 6) and the second pipe system (8).
The first pipe system (3, 6) starts from a well (1) or a pumping well whose water source is groundwater, passes through the heat exchange section (11) and the ground, and again passes through the well (1) or the well. The groundwater laid so as to return to the pumping well and flowing through the first pipe system (3, 6) is pumped from the well (1) or the pumping well by the first pump (2) and is pumped from the first pipe system. A groundwater heat utilization system characterized in that (3, 6) is pumped and discharged to the well (1) or the pumping well. In the geothermal heat utilization system according to claim 1,
The first pipe system (3, 6) is laid downstream from the heat exchange unit (11) so as to be able to communicate with the third pipe system (12) communicating with the water storage tank (14). Geothermal heat utilization system. In the geothermal heat utilization system according to claim 2,
The first pipe system (3, 6) is the third pipe system (3, 6) by the direction switching means (5) in which the opening degree with respect to the third pipe system (12) can be set within the range of 0 to 100 [%]. A geothermal heat utilization system characterized by communicating with 12). In the geothermal heat utilization system according to any one of claims 1 to 3,
A water level sensor (4) that measures the water level of the well (1) and
A control device (15) for controlling the direction switching means (5) is provided.
The control device (15) determines the opening degree of the direction switching means (5) with respect to the third pipe system (12) based on the measurement signal transmitted from the water level sensor (4). Medium heat utilization system. In the geothermal heat utilization system according to claim 4,
A first flow rate sensor (7) that measures the flow rate of the groundwater flowing through the first pipe system (3, 6), and
A second flow rate sensor (10) that measures the flow rate of the heat medium flowing through the second pipe system (8), and
A third flow rate sensor (13) for measuring the flow rate of the groundwater flowing through the third pipe system (12) is provided.
The control device (15) determines the opening degree of the direction switching means (5) with respect to the third pipe system (12) based on the measurement signals transmitted from the flow rate sensors (7, 10, 13). A geothermal heat utilization system characterized by In the geothermal heat utilization system according to any one of claims 1 to 5,
The second pump (9), the heat exchange unit (11), the direction switching means (5), the control device (15), the first flow rate sensor (7), the second flow rate sensor (10), and the like. A geothermal heat utilization system characterized in that all or part of the third flow rate sensor (13) is assembled inside a common building (18). In the geothermal heat utilization system according to claim 2,
A geothermal heat utilization system characterized in that the groundwater discharged from the third pipe system (12) to the water storage tank (14) is used as domestic water or disaster prevention water.