High-efficiency aquifer thermal storage heating and cooling system

Abstract

To provide a highly efficient aquifer thermal energy storage heating and cooling system that can utilize aquifer thermal energy storage more efficiently. To provide a highly efficient aquifer thermal energy storage heating and cooling system that can reduce maintenance costs by consolidating facilities. [Solution] This is a highly efficient aquifer thermal energy storage heating and cooling system 1, comprising: a thermal well 2 that reaches the aquifer 70 and creates a warm tropical water area 20 with a temperature higher than groundwater 700 around it; a cold well 3 that reaches the aquifer 70 in a location not affected by the warm tropical water area 20 and creates a cold tropical water area 30 with a temperature lower than groundwater 700 around it; a water supply device 4 that pumps and injects water through the thermal well 2 and cold well 3 and supplies water for indoor and outdoor use; indoor piping 5 that circulates to the water supply device 4; and outdoor piping 6 that circulates to the water supply device 4. An indoor heat exchanger 50 that exchanges heat between groundwater 700 and the indoor environment is connected to the indoor piping 5, and an outdoor heat exchanger 60 that exchanges heat between groundwater 700 and the outdoor environment is connected to the outdoor piping 6.

Description

Technical Field

[0001] The present invention relates to an energy technology that utilizes the temperature difference between an underground aquifer and the ground environment, and particularly to a highly efficient aquifer heat storage heating and cooling system that improves the heat storage in the aquifer and the utilization efficiency of the stored heat energy.

Background Art

[0002] A technology that circulates groundwater and utilizes the heat energy stored underground has already been developed by the applicant of the present application. For example, in the heating, cooling, snow melting, and heat collection method and apparatus using heat storage in an aquifer of Patent Document 1 (Japanese Patent Publication No. 7-76648), it has a hot water well and a cold water well. In the hot water well, a first pumping pump and a first injection pipe are provided. The upper part of the first pumping pump is connected to the inlet of the evaporator of the first heat pump by a pumping pipe. From the outlet of the evaporator, another pipe is connected to a small-diameter pipe buried in a pavement body via a first switching valve, and is also connected to the first injection pipe extending into the water in the hot water well. On the other hand, the end of the small-diameter pipe is connected to the inlet of the evaporator of the second heat pump by a pipe via a third switching valve. At the outlet of the evaporator of the second heat pump, a pipe is connected to a second injection pipe via a fourth switching valve and a second switching valve and extends into the water in the cold water well. Also, the second switching valve and the third switching valve are connected by a pipe. Moreover, the fourth switching valve is connected to a second pumping pipe and a second pumping pump installed in the water in the cold water well via a radiator-cum-heat collector provided in a building. And a circulation pipe is formed between the inlet and outlet of the condenser of the first heat pump and a hot water storage tank via a first circulation pump. A circulation pipe is formed between the inlet and outlet of the condenser of the second heat pump and the hot water storage tank via a third circulation pump. Another circulation pipe is formed between the hot water storage tank and a radiator-cum-heat collector inside the building via a second circulation pump.

[0003] Furthermore, technologies for storing heat in aquifers have been developed by parties other than the present applicant. For example, Patent Document 2 (Japanese Patent Publication No. 60-162141) describes a method and apparatus for utilizing underground thermal energy in a groundwater circulation system, in which groundwater pumped from one of several wells, one for summer and one for winter, which are connected to multiple underground aquifers, is injected into the other via a heat exchanger to provide heating and cooling. The apparatus describes an underground geothermal energy utilization device comprising a water-blocking device installed at the connection point between each aquifer and each well to block the passage of water through the connection point, and a mechanism that operates the water-blocking device to connect the well with an aquifer that has particularly excellent water permeability and heat storage capacity among the aquifers, and to block the connection between the other aquifers and the well. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 7-76648 [Patent Document 2] Japanese Patent Publication No. 60-162141 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the heating, cooling, snow melting, and heat collection method and apparatus using heat storage from an aquifer described in Patent Document 1 (Japanese Patent Publication No. 7-76648) has separate water supply pipes for pumping warm groundwater stored in the underground aquifer during the summer from a hot water well to the evaporator of a heat pump, and for pumping cold water from a cold water well into the building to create hot water by absorbing heat from inside the building. Thus, the hot water well and the cold water well require two water supply pipes, one for pumping and one for returning the water.

[0006] Furthermore, the method and apparatus for utilizing underground thermal energy in the groundwater circulation system described in Patent Document 2 (Japanese Patent Publication No. 60-162141) still has room for improvement in terms of effective utilization of underground heat, as all of the groundwater pumped from the summer and winter wells undergoes heat exchange. In addition, the installation work requires manpower to find an aquifer with particularly excellent heat storage capacity, and furthermore, the maintenance of water-blocking devices such as airbags is required, raising concerns about soaring maintenance costs.

[0007] In view of these circumstances, one of the objectives of this invention is to provide a highly efficient aquifer thermal energy storage heating and cooling system that can utilize aquifer thermal energy storage more efficiently. Another objective is to provide a highly efficient aquifer thermal energy storage heating and cooling system that can reduce maintenance costs through facility consolidation. Furthermore, one of the challenges is to provide a highly efficient aquifer thermal energy storage heating and cooling system that can more efficiently heat and cool buildings by utilizing the groundwater of the aquifer. [Means for solving the problem]

[0008] In other words, in order to solve at least one of the aforementioned problems, the present invention provides a highly efficient aquifer thermal energy storage heating and cooling system that efficiently utilizes the heat stored in an aquifer, comprising: groundwater piping for pumping groundwater from a thermal well and injecting it into a cooling well after heat exchange, or pumping groundwater from a cooling well and injecting it into a thermal well after cooling; a water supply device for supplying groundwater to the groundwater piping; a heat pump installed in the groundwater piping; and heating piping connected to the heat pump for supplying a liquid heated using the groundwater from the thermal well supplied to the groundwater piping as a heat source for the heat pump.

[0009] The aforementioned groundwater piping is connected to a thermal well containing groundwater at a higher temperature than the surrounding area, and a cold well containing groundwater at a lower temperature than the surrounding area, and is configured to perform either pumping or injection of water through a single pipe. In other words, when used as a heat source for cooling, water is pumped from the cold well, used for cooling, and then injected into the thermal well. When used as a heat source for heating, water is pumped from the thermal well, used as a heat source for heating, and then injected into the cold well. In such groundwater piping, a switching valve can be provided upstream of the heat pump, so that groundwater is supplied to the heat pump only when groundwater from the thermal well is being sent to the groundwater piping. The heat pump uses the groundwater from the thermal well as a heat source to heat a liquid such as antifreeze, which can then be used as a heating source for indoor facilities. On the other hand, when cooling indoor facilities, the low-temperature groundwater pumped from the cooling well can be directly guided to the indoor facilities to provide cooling. For this reason, in the high-efficiency aquifer thermal energy storage heating and cooling system according to the present invention, the groundwater from the cooling well is used directly when cooling facilities, and the groundwater from the thermal well is guided to the heat pump when heating, so a switching valve is provided upstream of the heat pump.

[0010] Therefore, in the aquifer thermal energy storage heating and cooling system according to the present invention, heating pipes and cooling pipes are installed separately within the building. Groundwater from the heating well is supplied to the heat pump through the groundwater pipes, where the liquid is heated, and the heated liquid is sent to the heating pipes. Groundwater from the cooling wells can be sent directly to the cooling pipes. In particular, it is desirable that the groundwater pipes maintain airtightness throughout. This is to avoid the problem of pipe corrosion due to the ingress of air.

[0011] The water supply device is a device that supplies and circulates groundwater to the entire system and is not limited to pumps; for example, centrifugal pumps, positive displacement pumps, jet pumps, airlift pumps, siphons, gravity flow mechanisms, pressurized tank systems, etc., can be used. The water supply device can also be a submersible pump installed in the thermal well and / or cold well, and each submersible pump can be operated under control from the water supply device or from a separately installed control panel. Furthermore, the groundwater used for heating and cooling can be injected into the thermal well and cold well by the water supply device. The submersible pump can be equipped with a lifting pump in each of the thermal well and cold well, and a valve can be provided to switch between the thermal well and the cold well.

[0012] The high-efficiency aquifer thermal energy storage heating and cooling system of this invention allows the total length of the groundwater piping to be the same as, shorter than, or longer than the total length of the indoor groundwater piping (i.e., heating piping or cooling piping). The flow path diameter of the groundwater piping can also be the same as, narrower than, or wider than the indoor groundwater piping (i.e., heating piping or cooling piping). The portion of the groundwater piping other than the indoor groundwater piping (i.e., heating piping or cooling piping) can be covered with an insulating layer or insulating material. However, especially considering the temperature of the groundwater in the aquifer, in order to improve heating efficiency in winter, it is desirable to cover the groundwater piping upstream of the heat pump (i.e., downstream of the cooling piping) with a sufficient insulating layer or insulating material, and not provide an insulating layer or insulating material on the downstream side of the heat pump (or upstream side of the indoor liquid piping) of the groundwater piping.

[0013] This invention can also be used as an aquifer thermal storage and heat exchange system, in which a heat exchanger is connected to a facility to be heated or cooled, such as an indoor environment, to exchange heat between a heated liquid (e.g., antifreeze) guided through heating pipes or groundwater from a cooling well guided through cooling pipes, and an outdoor heat exchange facility is connected to the groundwater pipes to exchange heat between the groundwater and the outdoor environment.

[0014] The heat exchanger can be used in air conditioning systems, hot water supply systems, refrigeration / freezing systems, heating systems, cultivation facilities, heat storage tanks, heat pumps, energy storage devices, etc., installed in indoor heating and cooling facilities. The outdoor heat exchange equipment can be used in paved roads, parking lots, roofs, exterior walls, soccer pitches, rugby fields, golf courses, racecourses, heat storage tanks, heat pumps, agricultural facilities, snow melting systems, energy storage devices, etc. Therefore, in the aquifer heat storage heating and cooling system according to the present invention, it is desirable that the groundwater piping is connected to the outdoor heat exchange equipment, such as by burying the downstream side of the heat pump or cooling piping in the ground or in the parking lot or other outdoor pavement.

[0015] The highly efficient aquifer thermal energy storage heating and cooling system of this invention can also be configured such that the water supply device is installed in a separate control building. By installing the water supply device in a separate control building, the amount of work required for maintaining the water supply device can be reduced. Maintenance of the water supply device can be performed without being affected by bad weather. The water supply device can be protected from the effects of natural environmental factors such as changes in outside temperature and direct sunlight. Even if the control building consists only of a frame and roof, the effects of direct sunlight and snow accumulation can be reduced.

[0016] The high-efficiency aquifer thermal energy storage heating and cooling system of the present invention may include a control unit in the water supply device that controls the water supply. This control unit can also control the system so that in the summer, groundwater pumped from the cooling well is supplied to the groundwater piping, and the groundwater, after heat exchange by heating and cooling, is injected into the heating well, and in the winter, groundwater pumped from the heating well is used as a heat source for a heat pump before being injected into the cooling well.

[0017] According to the control unit, the water supply from the cold and hot wells, and the water supply from the hot wells, can be appropriately managed according to the season. For example, if the water supply system including the control unit is installed in the management building, maintenance can be performed more efficiently. [Effects of the Invention]

[0018] According to the high-efficiency aquifer thermal energy storage heating and cooling system of the present invention, it is possible to provide an aquifer thermal energy storage heating and cooling system that can utilize aquifer thermal energy storage more efficiently. In particular, since it is configured to pump or inject water from a warm water well or a cold water well with a single pipe, it is possible to provide an aquifer thermal energy storage heating and cooling system that can reduce not only the installation process but also the maintenance work hours. Furthermore, since the groundwater in the cold water well is directly used for cooling the heating and cooling facility, it is possible to operate at a reduced cost. On the other hand, during heating, the heat of the groundwater in the warm water well can be efficiently utilized for heating, thus realizing a high-efficiency aquifer thermal energy storage heating and cooling system that can efficiently utilize the heat of the groundwater in the aquifer.

Brief Description of the Drawings

[0019] [Figure 1] It is a perspective view showing the summer operation of the aquifer thermal energy storage heating and cooling system of the present invention. [Figure 2] It is a perspective view showing the winter operation of the aquifer thermal energy storage heating and cooling system of the present invention.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, the high-efficiency aquifer thermal energy storage heating and cooling system according to the present embodiment will be specifically described with reference to the drawings. In particular, in this embodiment, a warm water well 2 that reaches the aquifer 70 and creates a warm thermal storage zone 20 with a temperature higher than the surrounding groundwater 700, a cold water well 3 that reaches the aquifer 70 at a position not affected by the thermal influence from the warm thermal storage zone 20 and creates a cold thermal storage zone 30 with a temperature lower than the surrounding groundwater 700, a water supply device 4 that pumps and injects water through the warm water well 2 and the cold water well 3 and supplies water to indoor and outdoor pipes, a heat pump 8, indoor pipes 5 (i.e., "cooling pipes" and "heating pipes") that circulate in the water supply device 4, and outdoor pipes 6 (i.e., "groundwater pipes") that circulate in the water supply device 4.

[0021] As shown in FIGS. 1 and 2, the high-efficiency aquifer thermal storage heating and cooling system 1 can be installed in a target site 7 including a building 71 where the indoor piping 5 is to be installed, a parking lot 72 where the outdoor piping 6 is to be installed, and an administration building 73 where the water supply device 4 is to be installed. The aquifer 70 is a highly permeable formation such as a sand layer or gravel layer underground in the target site 7 filled with groundwater 700.

[0022] The heat well 2 can be buried to reach a depth that reaches the aquifer 70 with a substantially constant temperature throughout the year within the target site 7, for example, a depth of around 10 m underground. This heat well 2 is, for example, a closed well that injects groundwater 700 at a higher temperature than the surroundings to create a thermally stored water zone 20. The heat well 2 can pump up groundwater 700 at a higher temperature than the surroundings from the thermally stored water zone 20.

[0023] The cold well 3 is buried to reach a depth in the aquifer 70 at a position sufficiently far from the thermally stored water zone 20 within the target site 7 so as not to be affected thermally, and injects groundwater 700 at a lower temperature than the surroundings to create a cold-stored water zone 30. The cold well 3 is, for example, a closed well. The cold well 3 can pump up groundwater 700 at a lower temperature than the surroundings from the cold-stored water zone 30. The heat well 2 and the cold well 3 can be provided with pumping pumps (submersible pumps) 200 and 300.

[0024] The water supply device 4 connects the respective reciprocating pipes 201 and 301 of the heat well 2 and the cold well 3. The water supply device 4 connects the indoor piping 5 and the outdoor piping 6, and circulates the pumped groundwater 700 from the heat well 2 or the cold well 3 through the indoor piping 5 and the outdoor piping 6, and can inject water into the aquifer 70 through the heat well 2 or the cold well 3.

[0025] The reciprocating piping 201 of the thermal well 2, the reciprocating piping 301 of the cold well 3, the indoor piping 5, and the outdoor piping 6 are all insulated to reduce heat loss, and the intermediate sections that can be routed parallel to each other can be buried in the same U-shaped channel or trough. By consolidating the piping as much as possible, the ease of installation and subsequent maintenance can be improved.

[0026] The indoor piping 5 can be equipped with a circulation pump 51 and an indoor heat exchanger 50 installed in the building 71. The circulation pump 51 and the indoor heat exchanger 50 can be operated under the control of the water supply device 4. The indoor heat exchanger 50 can be an inverter-controlled air conditioner 501 having a heat pump 8 and a fan coil unit. In particular, during heating, the groundwater from the heating well is used as a heat source for the heat pump 8, and the liquid such as antifreeze heated by the heat pump 8 is guided to the indoor piping 5. On the other hand, during cooling, the groundwater from the cooling well 3 is sent directly to the indoor piping 5 without heat exchange by the heat pump 8. Therefore, the indoor piping consists of heating piping that guides the liquid such as antifreeze heated by the heat pump 8, and cooling piping that guides the groundwater from the cooling well directly. A switching valve is provided in the box where the control device is installed to switch whether the groundwater flowing through the outdoor piping 6 is guided through the cooling piping or to the heat pump 8.

[0027] The outdoor piping 6 may be equipped with a circulation pump 61 and an outdoor heat exchanger 60 embedded to allow heat transfer between it and the pavement layer 720 of the parking lot 72. The circulation pump 61 and the outdoor heat exchanger 60 can function under the control of the water supply device 4. The outdoor heat exchanger 60 may be located close to or in contact with the pavement layer 720, or partially or completely embedded in the pavement layer 720, and may be a heat exchange pipe that is laid out in a meandering shape with parallel adjacent straight sections.

[0028] The water supply device 4 may be equipped with a control unit 80 that controls the water pumps 200, 300 and circulation pumps 51, 61. The control unit 80 includes hardware and software such as a CPU, memory, real-time clock, water temperature sensor, air temperature sensor, motor driver, and control program. The main routine of the control unit 80's software can identify summer and winter based on the real-time clock (calendar information), execute a subroutine for summer during summer, and execute a subroutine for winter during winter.

[0029] Furthermore, the software (main routine) of the control unit 80 can execute a summer subroutine if it detects a temperature higher than the average summer temperature based on the temperature sensor during seasonal changes (such as April-May and September-October) or throughout the year, and execute a winter subroutine if it detects a temperature lower than the average winter temperature. The aquifer thermal storage heating and cooling system 1 has the water supply equipment 4 installed together in a separate management building 73, which reduces the man-hours required for installation and maintenance. The management building 73 protects the water supply equipment 4 from snow accumulation and changes in outside temperature, thus reducing heat loss and significantly reducing the burden of snow removal work for winter inspections and maintenance.

[0030] As shown in Figure 1, during the summer months from May to September, the control unit 80 pumps up groundwater 700 using the water pump 300 of the cooling well 3 and sequentially supplies it to the indoor piping 5 and outdoor piping 6 through the reciprocating piping 301. The groundwater 700 in the indoor piping 5 is supplied to the air conditioner (indoor heat exchanger 50) 501, where it exchanges heat with the indoor air of the building 71 to cool the interior.

[0031] The control unit 80 supplies groundwater 700, whose temperature has risen due to indoor air conditioning, to the outdoor piping 6. The groundwater 700 in the outdoor piping 6 is supplied to the heat exchange pipe (outdoor heat exchanger) 60, and in the process of circulation, absorbs solar heat accumulated in the pavement layer 720 of the parking lot 72. The heat exchange pipe 60 cools the pavement layer 720 of the parking lot 72. The control unit 80 injects groundwater 700 whose water temperature has become even higher than that of the aquifer 70 through the thermal well 2, forming a warm tropical water zone 20 in the aquifer 70.

[0032] As shown in Table 1, the high-efficiency aquifer thermal energy storage heating and cooling system 1 according to this embodiment was able to reduce CO2 emissions during the summer period by 64% compared to the conventional system using a heavy oil-fired hot air heater. [Table 1]

[0033] As shown in Table 2, the high-efficiency aquifer thermal energy storage heating and cooling system 1 according to this embodiment was able to reduce running costs during the summer period by 64% compared to the conventional system using a heavy oil-fired hot air heater. [Table 2]

[0034] As shown in Figure 2, during the winter months from October to April, the control unit 80 pumps groundwater 700 from the tropical water storage area 20 using the water pump 200 of the thermal well 2 and sequentially supplies it to the heat pump 8 and the outdoor piping 6 through the reciprocating piping 201. The groundwater 700 used as the heat source for the heat pump is supplied to the outdoor piping 6. The heat generated by the heat pump is supplied to the air conditioner (indoor heat exchanger 50) 501 via antifreeze circulation, where it exchanges heat with the indoor air of the building 71 to heat the interior.

[0035] The control unit 80 supplies groundwater 700, whose temperature has been lowered by indoor heating, to the outdoor piping 6. The groundwater 700 in the outdoor piping 6 melts snow on the pavement layer 720 of the parking lot 72 as it circulates through the heat exchange pipe (outdoor heat exchanger) 60. The control unit 80 injects the groundwater 700, whose water temperature has fallen below that of the aquifer 70 after circulating through the air conditioner 50 and the heat exchange pipe 60 of the parking lot 72, into the aquifer 70 through the cold well 3, forming a cold storage tropical water area 30 in the aquifer 70.

[0036] The groundwater 700, which is colder than the surrounding area and accumulated in the aforementioned cold storage tropical water area 30, can be pumped up again during the following summer period by the pumping pump 300 of the cold well 3, as described above, to cool the interior of the building 71 and to cool the pavement layer 720 of the parking lot 72. The high-efficiency aquifer thermal storage heating and cooling system 1 can be used repeatedly every summer and winter in the same manner as described above.

[0037] As shown in Table 3, the high-efficiency aquifer thermal energy storage heating and cooling system 1 according to this embodiment was able to reduce CO2 emissions during the winter period by 58% compared to the conventional system using a heavy oil-fired hot air heater. [Table 3]

[0038] As shown in Table 4, the high-efficiency aquifer thermal energy storage heating and cooling system 1 according to this embodiment was able to reduce running costs during the winter season by 58% compared to the conventional system using a heavy oil-fired hot air heater. [Table 4] [Industrial applicability]

[0039] The highly efficient aquifer thermal storage heating and cooling system of this invention can be used in indoor air conditioning systems, hot water supply facilities, refrigeration and freezing equipment, heating equipment, cultivation facilities, agricultural facilities, thermal storage tanks, heat pumps, and energy storage devices, as well as in outdoor applications such as snow melting on paved roads, parking lots, roofs, exterior walls, soccer pitches, rugby fields, golf courses, and racecourses. [Explanation of Symbols]

[0040] 1. High-efficiency aquifer thermal energy storage heating and cooling system 2 Thermal wells 20 Same Temperate tropical waters 3 cold well 30 Same cold storage tropical waters 4 Water supply device 5. Indoor Piping 6. Outdoor piping 7. Target Site 70 same aquifer 71 Same building 72 Same parking lot 73 Administration Building 8. Heat pump

Claims

1. A highly efficient aquifer thermal energy storage heating and cooling system that utilizes the heat stored in the aquifer with high efficiency, Groundwater piping that pumps groundwater from a thermal well, exchanges heat, and then injects it into a cooling well, or pumps groundwater from a cooling well, cools it, and then injects it into a thermal well, A water supply device for supplying groundwater to the aforementioned groundwater pipe, A heat pump installed in the aforementioned groundwater piping, A highly efficient aquifer thermal energy storage heating and cooling system comprising a heating pipe connected to the heat pump and for supplying heated liquid, which is supplied using groundwater from a thermal well as a heat source for the heat pump.

2. The aforementioned groundwater piping is equipped with a switching valve on the upstream side of the heat pump. The highly efficient aquifer thermal energy storage heating and cooling system according to claim 1, wherein groundwater is supplied to the heat pump only when groundwater from the thermal well is being supplied to the groundwater piping.

3. The liquid supplied through the aforementioned heating pipe is antifreeze. The high-efficiency aquifer thermal energy storage heating and cooling system according to claim 1, further comprising cooling piping for supplying groundwater from the aforementioned cooling well to the interior of the building.

4. The aforementioned groundwater piping maintains airtightness throughout, Within the building, the aforementioned heating pipes and cooling pipes are installed separately. The groundwater from the thermal well is supplied to the heat pump through the groundwater piping, where the liquid is heated, and the heated liquid is then sent to the heating piping. The highly efficient aquifer thermal energy storage heating and cooling system according to claim 1, wherein groundwater from the cooling well is directly supplied to the cooling piping.

5. The high-efficiency aquifer thermal energy storage heating and cooling system according to claim 1, wherein the groundwater piping is buried in a parking lot or other outdoor pavement or ground on the downstream side of the heat pump or cooling piping.

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