Geothermal heat utilizing system

Abstract

To achieve energy saving by effectively utilizing heat of underground water.SOLUTION: A geothermal heat utilizing system includes: a storage part 3 for storing underground water A pumped up in a pumping up part 2; an air conditioning utilization part 4 for performing air conditioning by utilizing heat of the underground water A stored in the storage part 3; an underground water utilization supply part 5 for supplying the underground water A stored in the storage part 3 to a use spot C; and a water level control part 7. The air conditioning utilization part 4 circulates the underground water A between the air conditioning heat exchange part 41 and the storage part 3, and performs air conditioning by utilizing heat acquired in the air conditioning heat exchange part 41. The water level control part 7 can freely change and set a set water level of the underground water A stored in the storage part 3 according to a use state of the underground water A by the underground water utilization supply part 5, and, about the set water level, sets the set water level to a low water level at a low side at the timing before a use start just before the use start timing when utilization of the underground water A in the air conditioning heat exchange part 4 starts, and changes and sets the set water level to a high water level at a high side from the low water level according to the use start timing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a geothermal energy utilization system that performs air conditioning by utilizing the heat contained in groundwater. [Background technology]

[0002] This geothermal energy utilization system is known to include a pumping section that pumps up groundwater (well water), a storage section that stores the groundwater pumped by the pumping section, and an air conditioning utilization section that performs air conditioning by using the heat contained in the groundwater stored in the storage section (see, for example, Patent Document 1).

[0003] In the geothermal energy utilization system described in Patent Document 1, the air conditioning utilization section is equipped with a heat pump device or the like that uses groundwater as a heat source by exchanging heat between a refrigerant and groundwater, and cools or heats the indoor air to cover the thermal load of the building. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-080252 Summary of the Invention [Problem to be solved by the invention]

[0005] In the geothermal energy utilization system described in Patent Document 1, groundwater in a storage unit is used to cover the heat load, and for example, groundwater is pumped up and stored in the storage unit according to the amount of groundwater used, etc. Therefore, the amount of groundwater stored in the storage unit is kept at a constant level that is sufficient to cover the heat load of the building.

[0006] However, because heat is released from the groundwater stored in the storage unit, the amount of heat released from the groundwater increases as the time between storage in the storage unit and use in the air conditioning utilization unit increases, making it impossible to effectively utilize the heat (cold energy) originally contained in the groundwater in the air conditioning utilization unit, which is disadvantageous in terms of energy conservation.

[0007] In order to suppress heat radiation from the groundwater stored in the storage unit, it is possible to insulate the storage unit, but in this case, an insulating structure or the like must be added, which not only complicates the configuration and increases costs, but also results in some heat radiation loss even if the storage unit is insulated.

[0008] In view of this situation, a main object of the present invention is to provide a geothermal energy utilization system that can effectively utilize the heat contained in groundwater and achieve energy savings. [Means for solving the problem]

[0009] A first characteristic configuration of the present invention is a pumping unit that pumps up groundwater, a storage section that stores the groundwater pumped up by the pumping section; an air conditioning utilization unit that performs air conditioning by utilizing the heat of the groundwater stored in the storage unit; a groundwater consumption supply unit that supplies the groundwater stored in the storage unit to a point of use; a water level control unit that controls the operation state of the pumping unit to control the water level of the groundwater stored in the storage unit, The air conditioning utilization unit is configured to circulate groundwater between the air conditioning heat exchange unit and the storage unit, and perform air conditioning using heat acquired by the air conditioning heat exchange unit, The water level control unit is capable of freely changing and setting a set water level of the groundwater stored in the storage unit according to the usage status of the groundwater by the groundwater usage and supply unit, and The set water level is set to a low water level at the pre-use start timing just before the start of use timing when groundwater usage in the air conditioning usage section begins, and is then changed from the low water level to a high water level at the start of use timing.

[0010] According to this configuration, the water level control unit changes the set water level of the groundwater stored in the storage unit depending on the groundwater usage status by the groundwater usage supply unit, allowing groundwater to be stored in the storage unit while ensuring the planned amount of groundwater to be used by the groundwater usage supply unit. Furthermore, the water level control unit sets the set water level to a low level before usage begins, and then changes the set water level from the low level to a high level in accordance with the usage start timing. This allows the pumping unit to pump up groundwater in accordance with the usage start timing. This shortens the time from when the groundwater is stored in the storage unit until it is used by the air conditioning usage unit, suppressing heat radiation from the groundwater. This enables air conditioning that effectively utilizes the heat (e.g., cold) contained in the groundwater, resulting in energy savings.

[0011] A second characteristic configuration of the present invention is that the water level control unit changes the set water level to a lower level as the groundwater usage supply unit uses groundwater until the pre-use timing arrives.

[0012] According to this configuration, the water level control unit changes the set water level to a lower level as the groundwater use supply unit uses groundwater, so that the set water level can be set to the lower water level before use begins. This allows the pumping unit to pump up a larger amount of groundwater in time with the start of use, enabling efficient air conditioning that makes effective use of the heat contained in the groundwater.

[0013] A third characteristic configuration of the present invention is provided with a plurality of water level control modes in which the set water level is set in advance, The water level control unit executes a water level control mode selected from a plurality of water level control modes in accordance with the usage status of the groundwater by the groundwater usage / supply unit.

[0014] According to this configuration, the water level control unit only needs to switch the control mode depending on the groundwater usage status, which simplifies the control configuration for changing and setting the set water level. [Brief explanation of the drawings]

[0015] [Figure 1] Diagram showing the first water level control mode in the schematic configuration of the geothermal energy utilization system [Figure 2] Diagram showing the second water level control mode in the schematic configuration of the geothermal energy utilization system [Figure 3] Diagram showing the third water level control mode in the schematic configuration of the geothermal energy utilization system [Figure 4] Diagram showing the fourth water level control mode in the schematic configuration of the geothermal energy utilization system DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a geothermal energy utilization system according to the present invention will be described with reference to the drawings. As shown in Figure 1-4, this geothermal energy utilization system 1 includes a pumping section 2 that pumps up groundwater A, a storage section 3 that stores the groundwater A pumped up by the pumping section 2, an air conditioning utilization section 4 that performs air conditioning using the heat contained in the groundwater A stored in the storage section 3, a groundwater usage supply section 5 that supplies the groundwater A stored in the storage section 3 to the point of use, and a return section 6 that returns the groundwater A stored in the storage section 3 to the ground.

[0017] 1 to 4 all show the schematic configuration of the geothermal energy utilization system 1, and differ only in the areas where groundwater A and air-conditioning heat medium B flow and the water level of the groundwater A in the storage section 3, and the areas where groundwater A and air-conditioning heat medium B flow are indicated by thick lines. Below, the schematic configuration of the geothermal energy utilization system 1 will basically be explained using FIG. 1.

[0018] As shown in Figure 1, the pumping section 2 is equipped with a pumping well 21 in which underground groundwater A is stored, a source water tank 22 in which the groundwater A pumped from the pumping well 21 is stored, and a filtration processing section 23 in which the groundwater A supplied from the source water tank 22 to the storage section 3 is filtered.

[0019] A first groundwater supply line K1 is provided to supply groundwater A from the pumping well 21 to the source water tank 22, and a pumping pump 24 is disposed on the pumping well 21 side of the first groundwater supply line K1. The source water tank 22 is provided with a first water level detection unit S1 that detects the water level of the groundwater in the source water tank 22, and a pumping pump control unit (not shown) that controls the operating state of the pumping pump 24 based on the detection information of the first water level detection unit S1, etc.

[0020] When supplying groundwater A from the pumping well 21 to the storage section 3, depending on various conditions, such as the location of the pumping well 21 and the storage section 3 being far apart, or the need to filter the groundwater A in the filtration processing section 23, it may take a certain amount of time for the pumping well 21 to actually supply the groundwater A to the storage section 3, and there may be a time delay between the start of supply and when the groundwater A can actually be supplied to the storage section 3.

[0021] Therefore, the source water tank 22 ensures that the water level of the groundwater A in the source water tank 22 is equal to or higher than a predetermined level, and the groundwater A in the source water tank 22 is supplied to the storage unit 3, so that the groundwater A can be supplied to the storage unit 3 without delay from the start of supply. For example, the pumping pump control unit monitors the detection information of the first water level detection unit S1, and when the groundwater level in the source water tank 22 detected by the first water level detection unit S1 falls below the predetermined level, the pumping pump control unit operates the pumping pump 24 to supply groundwater A from the pumping well 21 to the source water tank 22, as shown by the thick line in Figure 1, thereby ensuring that the water level of the groundwater A in the source water tank 22 is equal to or higher than the predetermined level. Incidentally, the operation of the pumping pump 24 can be stopped, for example, when the water level of the groundwater A in the source water tank 22 detected by the first water level detection unit S1 reaches the predetermined level or a level higher than the predetermined level by a set amount.

[0022] A second groundwater supply line K2 is provided to supply groundwater A from the source water tank 22 to the filtration treatment unit 23, and a first groundwater supply pump P1 is disposed midway along the second groundwater supply line K2. A third groundwater supply line K3 is provided to supply groundwater A from the filtration treatment unit 23 to the storage unit 3. By operating the first groundwater supply pump P1, as shown by the bold line in Fig. 1, the groundwater A from the source water tank 22 is supplied to the filtration treatment unit 23 through the second groundwater supply line K2, and the groundwater A filtered in the filtration treatment unit 23 is supplied to the storage unit 3 through the third groundwater supply line K3.

[0023] The storage unit 3 can be configured, for example, as a utility water tank or the like disposed in an equipment pit of a building. For example, groundwater A is used as utility water at a utility water usage point C in the building, and the storage unit 3 has a capacity sufficient to store the amount of utility water (groundwater A) used at the utility water usage point C in one day in the building.

[0024] The air conditioning utilization unit 4 is equipped with an air conditioning heat exchange unit 41 that exchanges heat between groundwater A and an air conditioning heat medium B. As shown by the bold line in Figure 4, groundwater A is circulated between the air conditioning heat exchange unit 41 and the storage unit 3, and the heat acquired by the air conditioning heat exchange unit 41 is used for air conditioning. A groundwater circulation path 42 is provided to circulate the groundwater A between the storage unit 3 and the air conditioning heat exchange unit 41, and a groundwater circulation pump 43 is disposed at the supply side of the groundwater circulation path 42 from the storage unit 3 to the air conditioning heat exchange unit 41. An air conditioning heat medium circulation path 44 is provided to circulate the air conditioning heat medium B between the air conditioner (not shown) and the air conditioning heat exchange unit 41. The air conditioning heat medium B is circulated and supplied from the air conditioning heat exchange unit 41 to the air conditioner through the air conditioning heat medium circulation path 44 by a pump (not shown) or the like.

[0025] Although not shown in Figure 4 etc., the air conditioner may be, for example, a radiant air conditioner that cools or heats the air in a room by radiating heat from an air-conditioning heat medium B from a panel disposed on a wall or ceiling. The air conditioner is not limited to a radiant air conditioner, and any other air conditioner may be used as long as it performs air conditioning using the heat from the air-conditioning heat medium B.

[0026] As shown by the bold line in Fig. 1 , the groundwater use supply unit 5 supplies the groundwater A stored in the storage unit 3 to a use point C, and uses the groundwater A at the use point C. For example, the groundwater A supplied at the use point C can be used as is as utility water. Examples of the use point C that can be used include a sprinkler for irrigation and irrigation, a sprinkler device for the air heat exchanger in an air-cooled heat pump chiller, and a flush water supply device for toilets, etc. The groundwater use supply unit 5 is provided with a fourth groundwater supply conduit K4 to supply groundwater A from the storage unit 3 to the use point C, and a second groundwater supply pump P2 is disposed midway along the fourth groundwater supply conduit K4.

[0027] As shown in Figure 1, the return water section 6 is for returning a portion of the groundwater A stored in the storage section 3 into the ground, and is provided with a return water well 61 and a return water channel 62 for returning the groundwater A from the storage section 3 to the return water well 61. The storage section 3 is provided with a temperature detection section T for detecting the temperature of the groundwater A stored in the storage section 3, a return water pump 63 is provided midway along the return water channel 62, and a return water pump control section (not shown) for controlling the operating state of the return water pump 63 based on the detection information of the temperature detection section T, etc.

[0028] For example, the return pump control unit monitors the detection information of the temperature detection unit T, and when the temperature of the groundwater A stored in the storage unit 3 detected by the temperature detection unit T becomes higher than a predetermined temperature, the return pump control unit operates the return pump 63 to return the groundwater A from the storage unit 3 to the return well 61 through the return path 62. When the return well 61 becomes full of water, or when the temperature of the groundwater A stored in the storage unit 3 becomes lower than a predetermined temperature, the return pump control unit stops the operation of the return pump 63.

[0029] In the geothermal energy utilization system 1, as shown in Fig. 4, not only does the air conditioning utilization unit 4 use the heat of the groundwater A stored in the storage unit 3 to perform air conditioning, but as shown in Fig. 1-4, the groundwater use supply unit 5 supplies the groundwater A in the storage unit 3 to a usage point C, so that the groundwater A can also be used as utility water at the usage point C. To this end, a water level control unit 7 is provided that controls the water level of the groundwater A stored in the storage unit 3 according to the usage status (amount of usage) of the groundwater A at the usage point C by the groundwater use supply unit 5.

[0030] As shown in Fig. 1, the storage unit 3 is equipped with a second water level detection unit S2 that detects the water level of the groundwater A stored in the storage unit 3. Based on the detection information from the second water level detection unit S2, the water level control unit 7 controls the operating state of the first groundwater supply pump P1 and other components in the pumping unit 2 so that the water level of the groundwater A stored in the storage unit 3 becomes equal to the set water level. When the water level of the groundwater A stored in the storage unit 3 detected by the second water level detection unit S2 falls below the set water level, the water level control unit 7 operates the first groundwater supply pump P1 and other components in the pumping unit 2, thereby supplying groundwater A from the pumping well 21 via the source water tank 22 to the storage unit 3, as shown by the bold line in Fig. 1, and adjusting the water level of the groundwater A stored in the storage unit 3 to the set water level (for example, the first set water level Q1 in Fig. 1). Incidentally, with regard to stopping the operation of the first groundwater supply pump P1 etc. in the pumping section 2, for example, when the water level of the groundwater A stored in the storage section 3 detected by the second water level detection section S2 becomes equal to or higher than the set water level or a set amount higher than the set water level, the water level control section 7 can stop the operation of the first groundwater supply pump P1 etc. in the pumping section 2.

[0031] Regarding the set water level of the groundwater A stored in the storage unit 3, the water level control unit 7 is configured to be able to freely change and set the set water level of the groundwater A stored in the storage unit 3 according to the usage status (amount of usage) of the groundwater A at the usage point C by the groundwater usage supply unit 5, as shown in Figures 1-4, in order to cover at least the amount of groundwater A used at the usage point C by the groundwater usage supply unit 5. Figure 1 shows the state when set to the first set water level Q1, Figure 2 shows the state when set to the second set water level Q2, Figure 3 shows the state when set to the third set water level Q3, and Figure 4 shows the state when set to the fourth set water level Q4.

[0032] The water level control unit 7 can set the set water level for each time period, for example, using one day as a reference cycle, depending on the time period and amount of groundwater A used at the use point C by the groundwater use / supply unit 5. This allows the set water level of the groundwater A stored in the storage unit 3 to be controlled within the reference cycle (one day) in such a way that the higher the amount of use, the higher the water level is set for each time period, for example, early morning, from early morning to daytime, daytime, and nighttime. This makes it possible to efficiently use the groundwater A in the storage unit 3 without storing an insufficient or excessive amount of groundwater A for the amount of groundwater A used at the use point C in each time period.

[0033] In particular, in the summer, the cold energy contained in the groundwater A stored in the storage section 3 is easily dissipated. If the time between the time when the groundwater A is stored in the storage section 3 and the time when it is used in the air-conditioning utilization section 4 is long, it becomes difficult to perform air-conditioning that effectively utilizes the cold energy contained in the groundwater A in the air-conditioning utilization section 4. Furthermore, when air-conditioning is performed using the groundwater A in the storage section 3 in the air-conditioning utilization section 4 in the summer, the groundwater A whose cold energy has been used returns to the storage section 3 from the air-conditioning heat exchange section 41, causing the temperature of the groundwater A in the storage section 3 to rise. Therefore, if the temperature of the groundwater A in the storage section 3 is high at the time when the use of the groundwater A in the air-conditioning utilization section 4 begins, the temperature of the groundwater A in the storage section 3 will quickly rise to a high temperature that cannot be used for air-conditioning, making it difficult to perform air-conditioning that effectively utilizes the cold energy contained in the groundwater A.

[0034] Therefore, the water level control unit 7 grasps the timing for starting use of the groundwater A in the air conditioning utilization unit 4, and sets the set water level of the groundwater A stored in the storage unit 3 to a low water level (for example, the third set water level Q3 in Figure 3) at a pre-use timing just before the use start timing, and then changes the set water level from the low water level (for example, the third set water level Q3 in Figure 3) to a high water level (for example, the fourth set water level Q4 in Figure 4) in accordance with the use start timing. This allows the water level control unit 7 to set the set water level to the low water level in the pre-use start timing, and then change the set water level from the low water level to the high water level in accordance with the use start timing.

[0035] Groundwater A can be pumped up in the pumping section 2 in accordance with the timing for starting use and then supplied to the storage section 3. This shortens the time from when the groundwater A is stored in the storage section 3 until it is used in the air conditioning utilization section 4, thereby suppressing heat radiation from the groundwater A. In addition, the temperature of the groundwater A in the storage section 3 at the timing for starting use can be lowered, allowing air conditioning in the air conditioning utilization section 4 to effectively utilize the cold energy and other properties of the groundwater A.

[0036] The water level control unit 7 sets the water level to a low level (e.g., the third set water level Q3 in FIG. 3) at the timing before use starts. However, until the timing before use starts, the set water level of the groundwater A stored in the storage unit 3 is changed to a lower level as the groundwater A is used by the groundwater use / supply unit 5 (e.g., the first set water level Q1 in FIG. 1 → the second set water level Q2 in FIG. 2 → the third set water level Q3 in FIG. 3). This allows the set water level of the groundwater A stored in the storage unit 3 to be set to a lower water level at the timing before use starts, allowing the pumping unit 2 to pump up a larger amount of groundwater A in accordance with the timing when use starts. This allows more groundwater A containing cold energy and the like to be stored in the storage unit 3, and enables the air-conditioning utilization unit 4 to efficiently utilize the cold energy and the like contained in the groundwater A.

[0037] The setting of the change in the set water level of groundwater A stored in the storage section 3 by the water level control section 7 will be explained based on Figure 1-4, while illustrating the usage status of groundwater A at the usage point C and the start timing of use of groundwater A in the air conditioning usage section 4.

[0038] Assume that the usage of groundwater A at usage point C of the building is, for example, as follows: During the nighttime and early morning hours, sprinklers are used to water and irrigate, and a flush water supply device is used to supply flush water to toilets, etc. During the daytime hours, a sprinkler device is used to sprinkle water on the air heat exchanger of an air-cooled heat pump chiller, and a flush water supply device is used to supply flush water to toilets, etc. From early morning until daytime, a flush water supply device is used to supply flush water to toilets, etc.

[0039] The start of use of groundwater A in the air conditioning utilization section 4 of the building is assumed to be from early morning to daytime, and the start timing of use is set to the time period from early morning to daytime, and the pre-use start timing is set to the time period from early morning to daytime.

[0040] When the water level control unit 7 changes and sets the set water level of the groundwater A stored in the storage unit 3, as shown in Figure 1-4, multiple water level control modes are provided in which the set water level of the groundwater A stored in the storage unit 3 is pre-set, and the water level control unit 7 executes a water level control mode selected from the multiple water level control modes depending on the usage status of the groundwater A by the groundwater usage supply unit 5.

[0041] For example, during a day that is the reference cycle, the water level control unit 7 selects and executes the first water level control mode shown in Figure 1 during the daytime hours, the second water level control mode shown in Figure 2 during the nighttime hours, the third water level control mode shown in Figure 3 during the early morning hours, and the fourth water level control mode shown in Figure 4 during the hours from early morning to daytime, depending on the amount of groundwater A used at the usage point C.

[0042] When setting the set water level of the groundwater A stored in the storage unit 3, it is necessary to cover the amount of groundwater A used at the usage point C during each time period. In this geothermal utilization system 1, the capacity of the pumping unit 2 to pump groundwater A from the pumping well 21 to the storage unit 3 (e.g., the amount of groundwater pumped per hour) is set to be greater than the total load of water sprinkled on the air heat exchanger in the air-cooled heat pump chiller and the supply of flush water to toilets, etc. by the flush water supply device (e.g., the total amount of water sprinkled on the air heat exchanger and the amount of flush water supplied to toilets, etc. per hour). Therefore, basically, the set water level of the groundwater A stored in the storage unit 3 should be set so as to cover the amount of water used for sprinkling and irrigation by sprinklers during the nighttime and early morning hours.

[0043] Therefore, in the first water level control mode shown in Figure 1, which is executed during the daytime, the set water level of the groundwater A stored in the storage section 3 is set to a first set water level Q1, which corresponds to the total amount used for sprinkler watering and irrigation during both the nighttime and early morning hours plus a set amount.

[0044] In the second water level control mode shown in Figure 2, which is executed during the nighttime hours, watering and irrigation are carried out using sprinklers, so the set water level of the groundwater A stored in the storage section 3 is set to a second set water level Q2, which corresponds to the amount used for watering and irrigation using sprinklers in the early morning hours of the next morning plus a set amount.

[0045] In the third water level control mode shown in Figure 3, which is executed during the early morning hours, watering and irrigation are performed using sprinklers, and the timing after this watering and irrigation (after groundwater A is used at use point C) is set as the timing before use begins, so the set water level of the groundwater A stored in storage section 3 is set to the third set water level Q3, which corresponds to the amount of flush water supplied to toilets, etc. by the flush water supply device.

[0046] In the fourth water level control mode shown in Figure 4, which is executed from early morning to daytime, the timing for starting use is set, so the set water level of the groundwater A stored in the storage section 3 is set to a fourth set water level Q4, which is higher than the first set water level Q1.

[0047] In this way, the water level control unit 7 controls the set water level of the groundwater A stored in the storage unit 3 to the first set water level Q1 shown in Figure 1 during the daytime, to the second set water level Q2 shown in Figure 2 during the nighttime, to the third set water level Q3 shown in Figure 3 during the early morning hours, and to the fourth set water level Q4 shown in Figure 4 during the time period from early morning to daytime. The magnitude relationship between the first to fourth set water levels Q1-Q4 is 3 )> First set water level Q1 (for example, 50m 3 )> Second set water level Q2 (for example, 30m 3 )> Third set water level Q3 (e.g. 8m 3 It is set to (approximately).

[0048] Because the pre-use timing is set for the early morning hours, the water level control unit 7 changes the set water level to a lower level depending on the time period until the start of use in the early morning hours, in the order of the first set water level Q1 in Fig. 1 for the daytime hours, the second set water level Q2 in Fig. 2 for the nighttime hours, and the third set water level Q3 in Fig. 3 for the early morning hours. This allows the set water level to be changed to a lower level in succession as groundwater A is used at the use location C and as time passes, and to be changed to the minimum third set water level Q3 in the early morning hours when the pre-use timing is set.

[0049] The water level control unit 7 changes the setting from the low water level to the higher water level in accordance with the time period from early morning to daytime, for which the start timing of use is set, by changing the setting from the third set water level Q3 in Fig. 3 for the early morning time period to the fourth set water level Q4 in Fig. 4 for the early morning to daytime time period. This allows the set water level to be changed from the minimum third set water level Q3 to the maximum fourth set water level Q4 as time passes from the early morning time period to the early morning to daytime time period.

[0050] The operation in each water level control mode will be explained below.

[0051] (First water level control mode) In the first water level control mode during the daytime, as shown by the bold line in Figure 1, the groundwater usage and supply unit 5 operates the second groundwater supply pump P2 to supply groundwater A from the storage unit 3 to points of use C, such as a sprinkler system and a flush water supply system, through the fourth groundwater supply line K4, thereby sprinkling water on the air heat exchanger in the air-cooled heat pump chiller and supplying flush water to toilets, etc. The set water level of the groundwater A stored in the storage unit 3 is set to a first set water level Q1, and the water level control unit 7 controls the operating state of the first groundwater supply pump P1 and other components in the pumping unit 2 based on the detection information from the second water level detection unit S2, thereby controlling the water level of the groundwater A stored in the storage unit 3 to the first set water level Q1.

[0052] (Second water level control mode) In the second water level control mode during the nighttime hours, as shown by the bold line in Figure 2, the groundwater use and supply unit 5 operates the second groundwater supply pump P2 to supply groundwater A from the storage unit 3 to the use points C, such as sprinklers and flush water supply devices, through the fourth groundwater supply line K4, for watering and irrigation by sprinklers and for supplying flush water to toilets, etc. The set water level of the groundwater A stored in the storage unit 3 is set to the second set water level Q2, which is lower than the first set water level Q1. Therefore, even if the water level of the groundwater A stored in the storage unit 3 drops due to watering and irrigation by sprinklers, the pumping unit 2 does not pump up the groundwater A, and the water level of the groundwater A stored in the storage unit 3 is maintained at or above the second set water level Q2.

[0053] Incidentally, if, due to some factor, the water level of the groundwater A stored in the storage section 3 falls below the second set water level Q2, the water level control section 7 controls the operating state of the first groundwater supply pump P1 etc. in the pumping section 2 based on the detection information of the second water level detection section S2, thereby controlling the water level of the groundwater A stored in the storage section 3 to the second set water level Q2.

[0054] (Third water level control mode) In the third water level control mode during the early morning hours, as shown by the bold line in Figure 3, the groundwater use and supply unit 5 operates the second groundwater supply pump P2 to supply groundwater A from the storage unit 3 to the use points C, such as sprinklers and flush water supply devices, through the fourth groundwater supply line K4, for watering and irrigation by sprinklers and for supplying flush water to toilets, etc. The set water level of the groundwater A stored in the storage unit 3 is set to the third set water level Q3, which is lower than the second set water level Q2. Therefore, even if the water level of the groundwater A stored in the storage unit 3 drops due to watering and irrigation by sprinklers, the pumping unit 2 does not pump up the groundwater A, and the water level of the groundwater A stored in the storage unit 3 is maintained at or above the third set water level Q3.

[0055] Incidentally, if, for some reason, the water level of the groundwater A stored in the storage section 3 falls below the third set water level Q3, the water level control section 7 controls the operating state of the first groundwater supply pump P1 etc. in the pumping section 2 based on the detection information of the second water level detection section S2, thereby controlling the water level of the groundwater A stored in the storage section 3 to the third set water level Q3.

[0056] (4th water level control mode) In the fourth water level control mode, which is used from early morning to midday, as shown by the bold line in Figure 4, the groundwater use / supply unit 5 operates the second groundwater supply pump P2 to supply groundwater A from the storage unit 3 through the fourth groundwater supply line K4 to a use point C, such as a flush water supply device, to provide flush water for toilets, etc. During the early morning to midday period, a usage start timing is set for the air conditioning utilization unit 4 to start using groundwater A. Therefore, the air conditioning utilization unit 4 operates the groundwater circulation pump 43 to circulate and supply groundwater A from the storage unit 3 to the air conditioning heat exchange unit 41, where heat exchange occurs between the groundwater A and the air conditioning heat medium B, and air conditioning is performed using the air conditioning heat medium B in the air conditioning unit.

[0057] The set water level of the groundwater A stored in the storage unit 3 is set to a fourth set water level Q4, and the water level control unit 7 controls the operating state of the first groundwater supply pump P1 and other components in the pumping unit 2 based on the detection information from the second water level detection unit S2 to control the water level of the groundwater A stored in the storage unit 3 to the fourth set water level Q4. The fourth set water level Q4 is set to a water level higher than the first set water level Q1 to cover the amount of water used for watering and irrigation by sprinklers during the nighttime and early morning hours (the amount used at the use point C). Therefore, in the fourth water level control mode, the pumping unit 2 can pump a sufficient amount of groundwater A into the storage unit 3, and more of the lower temperature groundwater A can be stored in the storage unit 3. Therefore, heat exchange between the groundwater A and the air conditioning heat medium B can be carried out effectively and efficiently in the air conditioning heat exchange section 41, and air conditioning using the cold heat of the air conditioning heat medium B can be carried out effectively and efficiently in the air conditioning device.

[0058] [Another embodiment] Other embodiments of the present invention will be described below. Note that the configurations of the embodiments described below are not limited to being applied independently, but can also be applied in combination with the configurations of other embodiments.

[0059] (1) In the above embodiment, the capacity of the pumping unit 2 to pump groundwater A from the pumping well 21 to the storage unit 3 (e.g., the amount of groundwater pumped per hour) is set to be greater than the total load of water sprayed on the air heat exchanger in the air-cooled heat pump chiller and the supply of flush water to toilets, etc. by the flush water supply device (e.g., the total amount of water sprayed on the air heat exchanger per hour and the amount of flush water supplied to toilets, etc.). The capacity of the pumping unit 2 to pump groundwater A from the pumping well 21 to the storage unit 3 can be changed as appropriate, for example, depending on the usage conditions at the usage location C.

[0060] When changing the capacity of the pumping section 2 to pump groundwater A from the pumping well 21 to the storage section 3, the set water level of the groundwater A to be stored in the storage section 3 can be set in accordance with the change in capacity, for example, in a manner such that the lower the capacity, the higher the water level is set.

[0061] (2) In the above embodiment, the pumping section 2 is configured to have a pumping well 21, a source water tank 22, and a filtration processing section 23. However, for example, the source water tank 22 can be omitted, and groundwater A can be supplied directly from the pumping well 21 to the filtration processing section 23, and the filtered groundwater A can be supplied to the storage section 3.

[0062] (3) In the above embodiment, when the water level control unit 7 changes and sets the set water level of the groundwater A stored in the storage unit 3, one day is used as the reference period and the set water level is set for each time period: early morning, early morning to daytime, daytime, and nighttime.However, the reference period can also be a period shorter or longer than one day, such as half a day or two days, and the length of the time period for setting the set water level can also be changed depending on the period of this reference period. [Explanation of symbols]

[0063] 1. Geothermal energy utilization system 2 Pumping section 3. Storage section 4 Air conditioning usage section 5 Groundwater Use and Supply Department 7 Water level control unit 41 Heat exchanger for air conditioning A Groundwater C Usage

Claims

1. a pumping section for pumping up groundwater; a storage section that stores the groundwater pumped up by the pumping section; an air conditioning utilization unit that performs air conditioning by utilizing the heat of the groundwater stored in the storage unit; a groundwater consumption supply unit that supplies the groundwater stored in the storage unit to a point of use; a water level control unit that controls the operation state of the pumping unit to control the water level of the groundwater stored in the storage unit, The air conditioning utilization unit is configured to circulate groundwater between the air conditioning heat exchange unit and the storage unit, and to perform air conditioning by utilizing heat acquired by the air conditioning heat exchange unit, The water level control unit is capable of freely changing and setting a set water level of the groundwater stored in the storage unit according to the usage status of the groundwater by the groundwater usage and supply unit, and The geothermal energy utilization system sets the set water level to a low water level at a timing before the start of use when groundwater utilization in the air conditioning utilization section begins, and then changes the setting from the low water level to a high water level at the start of use timing.

2. The geothermal energy utilization system according to claim 1, wherein the water level control unit changes the set water level to a lower level as the groundwater utilization supply unit uses groundwater until the pre-utilization timing arrives.

3. A plurality of water level control modes are provided in which the set water level is preset, 3. The geothermal energy utilization system according to claim 1, wherein the water level control unit executes a water level control mode selected from a plurality of water level control modes depending on the groundwater usage status by the groundwater usage supply unit.

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