Control apparatus, geothermal utilization system, control method, and program

Abstract

To provide a control apparatus, a geothermal utilization system, a control method, and a program which give less impact on underground environment.SOLUTION: A control apparatus according to the present invention has: a returning-water temperature acquiring unit for acquiring temperature of returning-water to an injection well in a geothermal utilization system which comprises a heat source well facility having a pumping well, the injection well, a well-side pipe extending from the pumping well to the injection well, and a heat exchanger provided in the middle of the well-side pipe, and a geothermal utilization circuit provided between the heat exchanger and a device; and a flow amount control unit for controlling a flow amount of a coolant flowing from the geothermal utilization circuit to the device based on the returning-water temperature.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a control device, a geothermal heat utilization system, a control method, and a program. [Background technology]

[0002] In recent years, geothermal energy utilization systems that utilize heat stored underground have been proposed.

[0003] As a related technique, for example, Patent Document 1 discloses a geothermal energy utilization system that stores cold or hot heat discharged from an air conditioning system underground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7179905 Summary of the Invention [Problem to be solved by the invention]

[0005] The geothermal energy utilization system disclosed in Patent Document 1 adjusts the amount of water injected from the pumping well to the return well depending on the set temperature of the groundwater returned to the return well. However, for example, when the heat load required by equipment such as an air conditioning system is large, the geothermal energy utilization system disclosed in Patent Document 1 may not be able to adjust the return water temperature. For this reason, the return water temperature can affect the underground environment.

[0006] The present disclosure aims to provide a control device, a geothermal heat utilization system, a control method, and a program that have little impact on the underground environment. [Means for solving the problem]

[0007] In order to solve the above problems, the control device of the present disclosure comprises a heat source well equipment including a pumping well, a return well, a well side piping extending from the pumping well to the return well, and a heat exchanger provided midway along the well side piping, and a geothermal heat utilization system including a geothermal heat utilization circuit provided between the heat exchanger and an equipment, a return water temperature acquisition unit that acquires a return water temperature to the return well, and a flow rate control unit that controls the flow rate of refrigerant flowing from the geothermal heat utilization circuit to the equipment based on the return water temperature.

[0008] The control device of the present disclosure comprises a heat source well equipment including a pumping well, a return well, a well side piping extending from the pumping well to the return well, and a heat exchanger provided midway along the well side piping, a geothermal heat utilization system including a geothermal heat utilization circuit provided between the heat exchanger and an equipment, and an auxiliary heat supply equipment provided in the equipment in parallel with the geothermal heat utilization circuit and including a heat source unit, the geothermal heat utilization system comprising: a return water temperature acquisition unit that acquires the return water temperature to the return water well, and a heat source unit control unit that controls the start and stop of the heat source unit based on the return water temperature.

[0009] The geothermal energy utilization system according to the present disclosure comprises the control device, the heat source well facility, and the geothermal energy utilization circuit.

[0010] The control method disclosed herein obtains the return water temperature to the return well of a geothermal energy utilization system including a heat source well equipment including a pumping well, a return well, a well-side piping extending from the pumping well to the return well, and a heat exchanger installed midway along the well-side piping, and a geothermal energy utilization circuit installed between the heat exchanger and an equipment, and controls the flow rate of refrigerant flowing from the geothermal energy utilization circuit to the equipment based on the return water temperature.

[0011] The control method disclosed herein obtains the return water temperature to the return well of a geothermal energy utilization system including a heat source well equipment comprising a pumping well, a return well, a well-side piping extending from the pumping well to the return well, a heat exchanger provided midway along the well-side piping, a geothermal energy utilization circuit provided between the heat exchanger and an equipment, and an auxiliary heat supply equipment provided in parallel with the geothermal energy utilization circuit and equipped with a heat source unit, and controls the start and stop of the heat source unit based on the return water temperature.

[0012] The program of the present disclosure causes a computer to acquire the return water temperature to the return well of a geothermal energy utilization system comprising a heat source well equipment comprising a pumping well, a return well, a well-side piping extending from the pumping well to the return well, and a heat exchanger installed midway along the well-side piping, and a geothermal energy utilization circuit installed between the heat exchanger and an equipment, and to control the flow rate of refrigerant flowing from the geothermal energy utilization circuit to the equipment based on the return water temperature.

[0013] The program of the present disclosure causes a computer to acquire the return water temperature to the return well of a geothermal energy utilization system comprising a heat source well equipment including a pumping well, a return well, a well-side piping extending from the pumping well to the return well, and a heat exchanger provided midway along the well-side piping, a geothermal energy utilization circuit provided between the heat exchanger and an equipment, and an auxiliary heat supply equipment provided in the equipment in parallel with the geothermal energy utilization circuit and including a heat source unit, and to control the start and stop of the heat source unit based on the return water temperature. Effect of the Invention

[0014] The control device, geothermal heat utilization system, control method, and program disclosed herein are less likely to have an impact on the underground environment. [Brief description of the drawings]

[0015] [Figure 1] 1 is a system diagram of a geothermal energy utilization system according to an embodiment of the present disclosure. [Diagram 2]1 is a configuration diagram showing an example of the installation state of a water level meter at a natural water level in a geothermal heat utilization system according to an embodiment of the present disclosure. FIG. [Diagram 3] 1 is a configuration diagram showing an example of the installation state of a water level meter during pumping and return of a geothermal energy utilization system according to an embodiment of the present disclosure. FIG. [Figure 4] FIG. 2 is a detailed system diagram of a flow rate control device according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a block diagram of a control device according to an embodiment of the present disclosure. [Figure 6] 4 is a flowchart of a method for controlling return water temperature according to an embodiment of the present disclosure. [Figure 7] 4 is a flowchart of a method for controlling return water temperature according to an embodiment of the present disclosure. [Figure 8] 1 is a flowchart of a method for controlling a pumping-side water level according to an embodiment of the present disclosure. [Figure 9] 4 is a flowchart of a method for controlling a return water level according to an embodiment of the present disclosure. [Figure 10] 1 is a graph showing an example of a concept of sharing heat load between a heat source well facility and an auxiliary heat supply facility according to an embodiment of the present disclosure. [Figure 11] 11 is an explanatory diagram of the effect of an example of hysteresis provided to the start-up temperature and stop temperature of a heat source unit according to an embodiment of the present disclosure. FIG. [Figure 12] 13 is an explanatory diagram of the function of an example of hysteresis provided to the start-up water level and the stop water level of the heat source unit according to an embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In all drawings, the same or corresponding components are denoted by the same reference numerals, and common descriptions will be omitted.

[0017] <Embodiment> An embodiment of a geothermal energy utilization system according to the present disclosure will be described with reference to Figs. (Configuration of geothermal energy utilization system) As shown in FIG. 1, the geothermal heat utilization system 1 includes a heat source well facility 10, a geothermal heat utilization circuit 20, an auxiliary heat supply facility 30, and a control device 50. The heat source well facility 10, the geothermal heat utilization circuit 20, and the equipment AA are connected in series in this order so as to be capable of receiving heat. The auxiliary heat supply equipment 30 and the equipment AA are connected in parallel to the heat source well equipment 10 and the geothermal heat utilization circuit 20 so as to be capable of receiving heat.

[0018] When cooling is being used in equipment AA (e.g., air conditioning load) (hereinafter referred to as "cooling operation"), the geothermal energy utilization system 1 uses the cold energy stored as cold water in the heat source well equipment 10 for cooling, and at the same time stores the waste heat from equipment AA in the heat source well equipment 10 as hot water. When heating is being used in equipment AA (hereinafter referred to as "heating operation"), the geothermal energy utilization system 1 uses the hot heat stored as hot water in the heat source well equipment 10 for heating, and at the same time stores the exhaust cold heat from equipment AA in the heat source well equipment 10 as cold water. For example, the geothermal energy utilization system 1 may be a system that uses the hot water exhaust heat from air conditioning in summer for heating in winter and the cold water exhaust heat from heating in winter for air conditioning in summer by switching between a pumping well and a return well according to the season.

[0019] (Configuration of heat source well equipment) The heat source well facility 10 comprises a hot water well 11, a cold water well 12, well-side piping 13, and a heat exchanger 14. The heat source well facility 10 further includes a water thermometer 15 and a water level gauge 16 on each well side of the hot water well 11 and the cold water well 12.

[0020] In order to utilize the stored heat in equipment AA, the heat source well facility 10 pumps groundwater from one of the hot water well 11 and the cold water well 12 to the surface, performs heat exchange on the surface for heat utilization, and injects the water into the other of the hot water well 11 and the cold water well 12. In other words, the heat storage utilization mode of the heat source well equipment 10 has a cold energy utilization mode in which groundwater is pumped from the cold water well 12 and injected into the hot water well 11 during cooling operation, and a hot energy utilization mode in which groundwater is pumped from the hot water well 11 and injected into the cold water well 12 during heating operation.

[0021] In the cold energy utilization mode, groundwater is pumped from the aquifer LY through the cold water well 12, so that the cold water well 12 functions as a pumping well. On the other hand, in the cold energy utilization mode, the pumped groundwater is returned to the aquifer LY via the hot water well 11, so that the hot water well 11 functions as a return well.

[0022] In the case of the heat utilization mode, groundwater is pumped from the aquifer LY via the hot water well 11, so that the hot water well 11 functions as a pumping well. On the other hand, in the case of the thermal utilization mode, the pumped groundwater is returned to the aquifer LY via the cold water well 12, so that the cold water well 12 functions as a return well.

[0023] (Composition of hot and cold water wells) Hot water well 11 and cold water well 12 each extend from the ground into aquifer LY. The hot water well 11 and the cold water well 12 are each equipped with a casing having a screen, and are configured so that groundwater from the aquifer LY can be taken into the hot water well 11 and the cold water well 12, and groundwater can be returned from the inside of the hot water well 11 and the cold water well 12 to the aquifer LY. During normal operation of the geothermal energy utilization system 1, hot water is stored in the aquifer LY around the hot water well 11, and cold water is stored in the aquifer LY around the cold water well 12. The hot water well 11 and the cold water well 12 are provided at a distance sufficiently far from each other so that the stored hot water and cold water do not mix.

[0024] (Well side piping configuration) The well-side piping 13 extends from the hot water well 11 to the cold water well 12 . The well-side piping 13 connects the hot water well 11 and the cold water well 12 . As shown in FIG. 1, a first end 131 which is one end of the well-side pipe 13 extends into the hot water well 11 and is immersed in the groundwater inside the hot water well 11. The other end 132 of the well-side piping 13 extends into the cold water well 12 and is immersed in the groundwater inside the cold water well 12 .

[0025] Each of the first end 131 and the second end 132 is provided with a submersible pump PP, a water injection valve VA, a check valve VB, etc., and is configured to pump water from each well into the well side piping 13, and to inject water from the well side piping 13 into each well. The submersible pump PP can change its output by inverter control in response to a command from the control device 50.

[0026] (Heat exchanger configuration) The heat exchanger 14 is provided midway along the well-side piping 13 . The heat exchanger 14 exchanges heat between the water in the well-side piping 13 and the heat medium on the geothermal heat utilization circuit 20 side.

[0027] During cooling operation (cold heat utilization mode), the heat exchanger 14 exchanges heat between cold water, which is groundwater pumped up from the cold water well 12 and flowing in the well-side piping 13, and the heat medium on the geothermal heat utilization circuit 20 side. The cold heat obtained by the heat medium on the geothermal heat utilization circuit 20 side is utilized by equipment AA via the geothermal heat utilization circuit 20. On the other hand, the hot water, which is the groundwater after the heat exchange, flows from the heat exchanger 14 through the well-side piping 13 and is injected into the hot water well 11. This injection causes hot water heat storage in the hot water well 11.

[0028] During heating operation (in the case of hot water utilization mode), the heat exchanger 14 exchanges heat between hot water, which is groundwater pumped up from the hot water well 11 and flowing in the well-side piping 13, and the heat medium on the geothermal heat utilization circuit 20 side. The hot water obtained by the heat medium on the geothermal heat utilization circuit 20 side is utilized by equipment AA via the geothermal heat utilization circuit 20. On the other hand, the cold water, which is the groundwater after the heat exchange, flows from the heat exchanger 14 through the well-side piping 13 and is injected into the cold water well 12. This injection causes cold water heat storage in the cold water well 12.

[0029] Here, "cold water" refers to water with a temperature lower than the initial ground temperature of the groundwater in the LY aquifer. On the other hand, "hot water" refers to water with a temperature higher than the initial ground temperature mentioned above. For example, the initial ground temperature of the LY aquifer is 18°C.

[0030] (Water temperature gauge configuration) The water thermometer 15 on the cold water well 12 side is provided midway along the well side piping 13 leading from the cold water well 12 to the heat exchanger 14. For example, the water thermometer 15 on the cold water well 12 side may be provided at a position on the ground surface directly above the cold water well 12. The water thermometer 15 on the cold water well 12 side measures the temperature of the water flowing in the well side piping 13 on the cold water well 12 side, and outputs the measurement result to the control device 50.

[0031] The water thermometer 15 on the hot water well 11 side is provided midway on the well side piping 13 leading from the heat exchanger 14 to the hot water well 11. For example, the water thermometer 15 on the hot water well 11 side may be provided at a position on the ground surface directly above the hot water well 11. The water thermometer 15 on the hot water well 11 side measures the temperature of the water flowing in the well side piping 13 on the hot water well 11 side, and outputs the measurement result to the control device 50.

[0032] During cooling operation (cold energy utilization mode), the water thermometer 15 on the side of the cold water well 12 functions as a water thermometer that measures the temperature of water pumped from the pumping well. At that time, the water thermometer 15 on the side of the cold water well 12 outputs the measurement result to the control device 50 as the pumped water temperature. On the other hand, during this cooling operation, the water thermometer 15 on the hot water well 11 side functions as a water thermometer for measuring the return water temperature to the return well. At that time, the water thermometer 15 on the hot water well 11 side outputs the measurement result to the control device 50 as the return water temperature.

[0033] During heating operation (heat utilization mode), the water thermometer 15 on the hot water well 11 side functions as a water thermometer that measures the temperature of water pumped from the pumping well. At that time, the water thermometer 15 on the hot water well 11 side outputs the measurement result to the control device 50 as the pumped water temperature. On the other hand, during this heating operation, the water thermometer 15 on the side of the cold water well 12 functions as a water thermometer for measuring the return water temperature to the return well. At that time, the water thermometer 15 on the side of the cold water well 12 outputs the measurement result to the control device 50 as the return water temperature.

[0034] (Water level gauge configuration)

[0035] A water level gauge 16 on the cold water well 12 side is provided inside the cold water well 12 . The water level gauge 16 on the cold water well 12 side measures the water level in the cold water well 12 and outputs the measurement result to the control device 50.

[0036] A water level gauge 16 on the hot water well 11 side is provided inside the hot water well 11. The water level gauge 16 on the hot water well 11 side measures the water level in the hot water well 11 and outputs the measurement result to the control device 50.

[0037] During cooling operation (cold energy utilization mode), the water level gauge 16 on the cold water well 12 side functions as a water level gauge that measures the pumping side water level, which is the water level of the pumping well. At that time, the water level gauge 16 on the cold water well 12 side outputs the measurement result to the control device 50 as the pumping side water level. On the other hand, during this cooling operation, the water level gauge 16 on the hot water well 11 side functions as a water level gauge that measures the return water side water level, which is the water level of the return well. At that time, the water level gauge 16 on the hot water well 11 side outputs the measurement result to the control device 50 as the return water side water level.

[0038] During heating operation (heat utilization mode), the water level gauge 16 on the hot water well 11 side functions as a water level gauge that measures the pumping side water level, which is the water level of the pumping well. At that time, the water level gauge 16 on the hot water well 11 side outputs the measurement result to the control device 50 as the pumping side water level. On the other hand, during this heating operation, the water level gauge 16 on the cold water well 12 side functions as a water level gauge for measuring the return water side water level, which is the water level of the return well. At that time, the water level gauge 16 on the cold water well 12 side outputs the measurement result to the control device 50 as the return water side water level.

[0039] For example, each water level gauge 16 measures the water level as the distance from the water surface to the position where the water level gauge 16 is set. For example, each water level gauge 16 may be provided to measure the water level shown in FIG. 2 at natural water levels. For example, each water level gauge 16 may be provided so as to measure the water level shown in FIG. 3 during pumping and during return.

[0040] (Configuration of geothermal energy utilization circuit) The geothermal heat utilization circuit 20 is provided between the heat exchanger 14 and the equipment AA. The geothermal heat utilization circuit 20 mediates and controls the heat exchange performed between the heat exchanger 14 and the equipment AA in response to commands from the control device 50. For example, the geothermal heat utilization circuit 20 may include a heat pump 21, a flow rate regulator 22, and a main pipe 23.

[0041] (Heat pump configuration) The heat pump 21 includes a condenser, an evaporator, a compressor, and the like. For example, the heat pump 21 is a turbo heat pump. The heat pump 21 is provided between the heat exchanger 14 and the flow rate regulator 22 . The heat pump 21 cools or heats the heat medium that has exchanged heat with the water in the well-side piping 13 in the heat exchanger 14. As a result, the heat pump 21 supplies the cold or hot stored heat obtained from the water in the well-side piping 13 to the equipment AA, while recovering the exhaust hot or cold heat discharged from the equipment AA and storing it in the water in the well-side piping 13 via the heat exchanger 14.

[0042] During cooling operation (cold heat utilization mode), the heat pump 21 provides the equipment AA with the cold heat stored in the well-side piping 13 via the heat exchanger 14 and the heat medium flowing between the heat pump 21 and the heat exchanger 14 and the heat medium flowing between the heat pump 21 and the equipment AA. On the other hand, the heat pump 21 stores the exhaust hot heat discharged from the equipment AA in the water in the well-side piping 13 via the heat exchanger 14 and the heat medium flowing between the heat pump 21 and the equipment AA.

[0043] During heating operation (heat utilization mode), the heat pump 21 provides the equipment AA with the stored heat obtained from the well-side piping 13 via the heat exchanger 14 and the heat medium flowing between the heat pump 21 and the heat exchanger 14 and the heat medium flowing between the heat pump 21 and the equipment AA. On the other hand, the heat pump 21 stores the exhaust cold heat discharged from the equipment AA in the water in the well-side piping 13 via the heat exchanger 14 and the heat medium flowing between the heat pump 21 and the equipment AA.

[0044] (Configuration of flow control device) The flow rate adjusting device 22 adjusts the flow rate FL of the heat medium flowing from the geothermal heat utilization circuit 20 to the equipment AA. 4, for example, the flow control device 22 may include a bypass valve 223 in order to adjust the flow rate FL by self-bypassing. Furthermore, the flow control device 22 may include a pump 221 and an electric valve 222 in the middle of the path connecting the heat pump 21 and the main pipe 23 in order to adjust the flow rate FL.

[0045] (Main piping configuration) A main pipe 23 extends from the flow control device 22 to the equipment AA. The main pipe 23 connects the flow rate control device 22 and the equipment AA so that the heat medium can circulate between the flow rate control device 22 and the equipment AA.

[0046] (Configuration of auxiliary heat supply equipment) The auxiliary heat supply facility 30 assists at least one of the hot heat supply and the cold heat supply provided by the heat source well facility 10 to the equipment AA. When cooling is being used in the equipment AA, the auxiliary heat supply equipment 30 supplies cold heat to the equipment AA and recovers waste heat from the equipment AA. When the equipment AA is using heating, the auxiliary heat supply equipment 30 supplies hot heat to the equipment AA and recovers exhaust cold heat from the equipment AA.

[0047] The auxiliary heat supply equipment 30 includes a plurality of heat source units 31 and auxiliary piping 32 . Each heat source unit 31 supplements at least one of the cold heat and the hot heat supplied to the equipment AA. For example, the multiple heat source units 31 include turbo chillers, air-cooled heat pumps, absorption type hot and cold water machines, and the like. The auxiliary piping 32 extends from the multiple heat source units 31 to the equipment AA. The auxiliary piping 32 connects the plurality of heat source units 31 and the equipment AA so that the heat medium can circulate between the plurality of heat source units 31 and the equipment AA.

[0048] For example, the auxiliary heat supply equipment 30 may be provided with an auxiliary flow control device 33 in the auxiliary piping 32. In this case, the auxiliary flow control device 33 has a bypass valve, a pump, and an electric valve similar to those of the flow control device 22, and adjusts the flow rate of the refrigerant flowing between the auxiliary heat supply equipment 30 and the equipment AA in response to a command from the control device 50.

[0049] (Control device configuration) As shown in FIG. 5, the control device 50 functionally includes a return water temperature acquisition unit 511 and a flow rate control unit 512. For example, the control device 50 may further functionally include a heat source unit control unit 513, a pumping side water level acquisition unit 514, a pumping flow rate control unit 515, a return side water level acquisition unit 516, and a return flow rate control unit 517.

[0050] The control device 50 includes, as its hardware configuration, a CPU 51, a memory 52, a communication interface 53, and a recording medium 54.

[0051] The CPU 51 is a processor that performs various functions by operating according to pre-prepared programs. The functions of the CPU 51 will be described later.

[0052] The memory 52 has a storage area necessary for the operation of the CPU 51 .

[0053] The communication interface 53 is a connection interface for communicatively connecting to other devices via a communication line or the like, and is configured to be able to send commands and responses to other devices and receive commands and responses from other devices.

[0054] The recording medium 54 is a local recording medium provided within the housing of the control device 50, and is a large-capacity storage device such as an HDD or SSD.

[0055] Next, the function of the CPU 51 of the control device 50 will be described. The CPU 51 operates according to a prepared program, thereby fulfilling the functions of the return water temperature acquisition unit 511 and the flow rate control unit 512 as described above. Furthermore, the CPU 51 may function as a heat source unit control unit 513, a pumping side water level acquisition unit 514, a pumping flow rate control unit 515, a return side water level acquisition unit 516, and a return flow rate control unit 517, as described above, by operating according to a pre-prepared program.

[0056] The return water temperature acquisition unit 511 acquires the measurement result of the water thermometer 15 on the cold water well 12 side or the water thermometer 15 on the hot water well 11 side as the return water temperature to the return well. The pumping-side water level acquisition unit 514 acquires the measurement result of the water level gauge 16 on the hot water well 11 side or the water level gauge 16 on the cold water well 12 side as the pumping-side water level. The return water level acquisition unit 516 acquires the measurement result of the water level gauge 16 on the cold water well 12 side or the water level gauge 16 on the hot water well 11 side as the return water level.

[0057] The flow rate control unit 512 controls the flow rate FL by controlling the flow rate adjustment device 22 based on the obtained return water temperature. For example, the flow rate control unit 512 controls the flow rate FL by controlling the flow rate adjustment device 22 based on the acquired pumping-side water level. For example, the flow rate control unit 512 controls the flow rate FL by controlling the flow rate adjustment device 22 based on the obtained return water level.

[0058] For example, the flow rate control unit 512 may adjust the flow rate of the refrigerant flowing between the auxiliary heat supply equipment 30 and equipment AA by controlling the auxiliary flow rate control device 33 based on the acquired return water temperature. For example, the flow rate control unit 512 may adjust the flow rate of the refrigerant flowing between the auxiliary heat supply equipment 30 and equipment AA by controlling the auxiliary flow rate control device 33 based on the acquired pumped-side water level. For example, the flow rate control unit 512 may adjust the flow rate of the refrigerant flowing between the auxiliary heat supply equipment 30 and equipment AA by controlling the auxiliary flow rate control device 33 based on the obtained return water level.

[0059] The heat source unit control unit 513 may control the start and stop of each heat source unit 31 based on the acquired return water temperature. For example, the heat source unit control unit 513 may control the start and stop of each heat source unit 31 based on the acquired pumped water level. For example, the heat source unit control unit 513 may control the start and stop of each heat source unit 31 based on the acquired return water level. For example, the heat source unit control unit 513 may perform step-up / step-down control of a plurality of heat source units 31.

[0060] The pumping flow rate control unit 515 controls the pumping flow rate from the pumping well based on the acquired pumping side water level. The return water flow rate control unit 517 controls the return water flow rate to the return well based on the acquired return water level.

[0061] (Control device operation) An example of the operation of the control device 50 of this embodiment will be described. The operation of the control device 50 corresponds to an embodiment of a control method. The control device 50 performs the steps shown in FIGS.

[0062] (Return water temperature control operation) First, the operation of the return water temperature control will be described. When the geothermal energy utilization system 1 is started, as shown in FIG. 6, the control device 50 determines whether or not the equipment AA is in cooling operation (ST00).

[0063] (Return water temperature control during cooling operation) If it is determined in ST00 that the system is in cooling operation (ST00: Yes), the return water temperature acquisition unit 511 acquires the measurement result of the water thermometer 15 on the hot water well 11 side as the return water temperature, and determines whether the acquired return water temperature is higher than a first startup temperature (e.g., 24°C) at which the heat source unit 31 should be started up (ST01). For example, the first startup temperature is a preset value.

[0064] If it is determined in ST01 that the acquired return water temperature is higher than the first startup temperature (ST01: Yes), the heat source unit control unit 513 determines whether or not there is a heat source unit 31 (another heat source unit) that can be started among the multiple heat source units 31 (ST02).

[0065] In ST02, if it is determined that there is a heat source unit 31 that can be activated (ST02: Yes), the heat source unit control unit 513 activates the heat source unit 31 that can be activated (ST03), and the control device 50 returns to performing ST01. For example, in ST03, the heat source machine control unit 513 first starts one of the heat source machines 31 that can be started (setting can be changed). If there are multiple heat source machines 31 that can be started, the heat source machine control unit 513 can perform step-up / step-down control by repeating ST01 to ST03. At that time, the heat source machine control unit 513 may perform step-up / step-down control by checking the amount of heat or flow rate supplied to the device AA. On the other hand, the flow control unit 512 controls the flow rate FL so that the return water temperature of the heat source well equipment 10 is within a preset tolerance (below a preset upper limit value), as described below, and suppresses the load on the heat source well equipment 10.

[0066] If it is determined in ST02 that there is no heat source unit 31 that can be started (ST02: No), the control device 50 determines whether or not protection of the aquifer LY should be prioritized over ensuring the air conditioning capacity of the equipment AA (ST04). For example, the control device 50 may determine whether or not protection of the aquifer LY should be prioritized over ensuring the air conditioning capacity of the equipment AA in accordance with a guideline input by a user or the like.

[0067] If it is determined in ST04 that protection of the aquifer LY should be prioritized (ST04: Yes), the flow rate control unit 512 controls the flow rate FL (ST05), and the control device 50 returns to performing ST01. For example, in ST05, the flow rate control unit 512 may perform control to reduce the flow rate FL by opening the bypass valve 223. This control makes it possible to reduce the load in the self-bypass and control the return water temperature. Furthermore, in ST05, the flow rate control unit 512 may control the auxiliary flow rate control device 33 to increase the flow rate of the heat medium (cold medium) flowing between the auxiliary heat supply equipment 30 and the equipment AA.

[0068] If it is determined in ST04 that the air conditioning capacity of the equipment AA should be ensured (ST04: No), the control device 50 stops the heat supply from the geothermal utilization system 1 to the equipment AA (ST06). After that, the users etc. consider using another system that can replace the geothermal utilization system 1 and ensure the air conditioning capacity of the equipment AA.

[0069] If it is determined in ST01 that the acquired return water temperature is not higher than the first start-up temperature (ST01: No), the return water temperature acquisition unit 511 determines whether the acquired return water temperature is lower than a first stop temperature (e.g., 20°C) at which the heat source unit 31 should be stopped (ST07). For example, the first stop temperature is a preset value. Here, in order to provide hysteresis between the start-up conditions and stop-up conditions of the heat source unit 31 when the geothermal energy utilization system 1 performs cooling operation on the unit AA, the first stop temperature is set lower than the first start-up temperature.

[0070] In ST07, if it is not determined that the acquired return water temperature is lower than the first stop temperature (ST07: No), the control device 50 returns to the execution of ST01.

[0071] If it is determined in ST07 that the acquired return water temperature is lower than the first stop temperature (ST07: Yes), the heat source unit control unit 513 determines whether or not there is any heat source unit 31 that is running among the multiple heat source units 31 (heat source units other than the heat source units included in the heat source well equipment 10) (ST08).

[0072] In ST08, if it is determined that there is a heat source unit 31 that is running (ST08: Yes), the heat source unit control unit 513 stops the running heat source unit 31 (ST09), and the control device 50 returns to executing ST01.

[0073] If it is determined in ST08 that no heat source unit 31 is in operation (ST08: No), the control device 50 returns to the execution of ST01.

[0074] If it is not determined in ST00 that the device is in cooling operation (ST00: No), the control device 50 determines whether the device AA is in heating operation (ST10).

[0075] If it is not determined in ST10 that the heating operation is in progress (ST10: No), the control device 50 performs other control such as causing the heat source well equipment 10 to perform cold heat storage operation or hot heat storage operation in the heat source well equipment 10 (ST11).

[0076] (Return water temperature control during heating operation) If it is determined in ST10 that the heating operation is in progress (ST10: Yes), as shown in Fig. 7, the return water temperature acquisition unit 511 acquires the measurement result of the water thermometer 15 on the cold water well 12 side as the return water temperature, and determines whether the acquired return water temperature is lower than a second startup temperature (e.g., 8°C) at which the heat source unit 31 should be started up (ST21). For example, the second startup temperature is a preset value.

[0077] If it is determined in ST21 that the acquired return water temperature is lower than the second startup temperature (ST21: Yes), the heat source unit control unit 513 determines whether or not there is a heat source unit 31 (another heat source unit) that can be started among the multiple heat source units 31 (ST22).

[0078] In ST22, if it is determined that there is a heat source unit 31 that can be activated (ST22: Yes), the heat source unit control unit 513 activates the heat source unit 31 that can be activated (ST23), and the control device 50 returns to executing ST21. For example, in ST23, the heat source machine control unit 513 first starts one of the heat source machines 31 that can be started (setting can be changed). If there are multiple heat source machines 31 that can be started, the heat source machine control unit 513 can perform step-up / step-down control by repeating ST21 to ST23. At that time, the heat source machine control unit 513 may perform step-up / step-down control by checking the amount of heat or flow rate supplied to the device AA. On the other hand, the flow control unit 512 controls the flow rate FL so that the return water temperature of the heat source well equipment 10 is within a preset tolerance (above a preset lower limit value), as described below, thereby suppressing the load on the heat source well equipment 10.

[0079] If it is determined in ST22 that there is no heat source unit 31 that can be started (ST22: No), the control device 50 determines whether or not protection of the aquifer LY should be prioritized over ensuring the air conditioning capacity of the equipment AA (ST24). For example, the control device 50 may determine whether or not protection of the aquifer LY should be prioritized over ensuring the air conditioning capacity of the equipment AA in accordance with a guideline input by a user or the like.

[0080] If it is determined in ST24 that protection of the aquifer LY should be prioritized (ST24: Yes), the flow rate control unit 512 controls the flow rate FL (ST25), and the control device 50 returns to performing ST21. For example, in ST25, the flow rate control unit 512 may perform control to reduce the flow rate FL by opening the bypass valve 223. This control makes it possible to reduce the load in the self-bypass and control the return water temperature. Furthermore, in ST25, the flow rate control section 512 may control the auxiliary flow rate control device 33 to increase the flow rate of the heat medium (hot heat medium) flowing between the auxiliary heat supply equipment 30 and the equipment AA.

[0081] If it is determined in ST24 that the air conditioning capacity of the equipment AA should be ensured (ST24: No), the control device 50 stops the heat supply from the geothermal utilization system 1 to the equipment AA (ST26). After that, the users etc. consider using another system that can replace the geothermal utilization system 1 and ensure the air conditioning capacity of the equipment AA.

[0082] If it is determined in ST21 that the acquired return water temperature is not lower than the second start-up temperature (ST21: No), the return water temperature acquisition unit 511 determines whether or not the acquired return water temperature is higher than a second stop temperature (e.g., 12°C) at which the heat source unit 31 should be stopped (ST27). For example, the second stop temperature is a preset value. Here, in order to provide hysteresis between the start-up conditions and stop-up conditions of the heat source unit 31 when the geothermal energy utilization system 1 performs heating operation on the unit AA, the second stop temperature is set higher than the second start-up temperature.

[0083] If it is not determined in ST27 that the acquired return water temperature is higher than the second stop temperature (ST27: No), the control device 50 returns to the execution of ST21.

[0084] If it is determined in ST27 that the acquired return water temperature is higher than the second stop temperature (ST27: Yes), the heat source unit control unit 513 determines whether or not there is any heat source unit 31 that is running among the multiple heat source units 31 (heat source units other than the heat source units included in the heat source well equipment 10) (ST28).

[0085] In ST28, if it is determined that there is a heat source unit 31 that is running (ST28: Yes), the heat source unit control unit 513 stops the running heat source unit 31 (ST29), and the control device 50 returns to performing ST21.

[0086] If it is determined in ST28 that no heat source unit 31 is in operation (ST28: No), the control device 50 returns to the execution of ST21.

[0087] (Operation of water level control of pumping well) The operation of the water level control of the pumping well will now be explained.

[0088] When the geothermal energy utilization system 1 is started, the pumping-side water level acquisition unit 514 acquires the measurement result of the water level gauge 16 on the pumping well side as the pumping-side water level, and judges whether the acquired pumping-side water level is higher than a first limit water level (e.g., 3 m) (ST41), as shown in Fig. 8. For example, the first limit water level is a preset value. Here, the first limit water level that is set is a water level below which the flow rate of pumped water should be limited and the heat source unit 31 should be started. In this water level control during cooling operation, the pumping well is the cold water well 12 and the return well is the hot water well 11. On the other hand, in this water level control during heating operation, the pumping well is the hot water well 11 and the return well is the cold water well 12.

[0089] In ST41, if it is determined that the acquired pumping side water level is not higher than the first limit water level (determined to be below the first limit water level) (ST41: No), the heat source unit control unit 513 determines whether there is a heat source unit 31 (another heat source unit) that can be started among the multiple heat source units 31 (ST42).

[0090] In ST42, if it is determined that there is a heat source unit 31 that can be activated (ST42: Yes), the heat source unit control unit 513 activates the heat source unit 31 that can be activated (ST43), and the control device 50 returns to executing ST41. For example, in ST43, the heat source machine control unit 513 first starts one of the heat source machines 31 that can be started (setting can be changed). If there are multiple heat source machines 31 that can be started, the heat source machine control unit 513 can perform step-up / step-down control by repeating ST41 to ST43. At that time, the heat source machine control unit 513 may perform step-up / step-down control by checking the amount of heat or flow rate supplied to the device AA.

[0091] In addition, in ST43, the pumping flow rate control unit 515 may control the pumping flow rate from the pumping well by limiting the capacity of the submersible pump on the pumping well side or by stopping the operation of the submersible pump PP on the pumping well side. On the other hand, the flow control unit 512 may control the flow rate adjustment device 22 to reduce the flow rate FL so that the return water temperature of the heat source well facility 10 is within the allowable value, thereby suppressing the load on the heat source well facility 10. Furthermore, the flow rate control unit 512 may control the auxiliary flow rate adjustment device 33 to increase the flow rate of the heat medium flowing between the auxiliary heat supply facility 30 and the equipment AA.

[0092] In ST41, if it is determined that the acquired pumping-side water level is higher than the first restriction water level (ST41: Yes), it is determined whether the acquired pumping-side water level is lower than a first release water level (for example, 10 m) (ST44). For example, the first release water level is a preset value. Here, the first release water level that is set is a water level at which the restriction on the pumped water flow rate should be released and the heat source unit 31 should be stopped when the water level reaches or exceeds this water level. Moreover, in order to provide hysteresis between the start condition and the stop condition of the heat source unit 31, the first release water level is set higher than the first restriction water level.

[0093] In ST44, if it is determined that the acquired pumping-side water level is lower than the first release water level (ST44: Yes), the control device 50 determines that the pumping restriction should not be released and returns to executing ST41.

[0094] In ST44, if the acquired pumping side water level is not determined to be lower than the first release water level (determined to be equal to or higher than the first release water level) (ST44: No), there is a possibility that the pumping restriction can be lifted, and the heat source machine control unit 513 determines whether or not there is any heat source machine 31 that is running among the multiple heat source machines 31 (heat source machines other than the heat source machines included in the heat source well equipment 10) (ST45).

[0095] If it is determined in ST45 that there is a heat source unit 31 that is running (ST45: Yes), the heat source unit control unit 513 stops the running heat source unit 31 (ST46), and the control device 50 returns to executing ST41. At that time, the pumping flow rate control unit 515 may control the pumping flow rate from the pumping well to be increased by removing the restriction imposed on the capacity of the submersible pump PP on the pumping well side or by starting the operation of the submersible pump PP on the pumping well side. On the other hand, the flow control unit 512 may control the flow control device 22 to increase the flow rate FL, and control the auxiliary flow control device 33 to decrease the flow rate of the heat medium flowing between the auxiliary heat supply equipment 30 and the equipment AA.

[0096] If it is determined in ST45 that there is no heat source unit 31 that is in operation (ST45: No), the control device 50 returns to the execution of ST41.

[0097] If it is determined in ST42 that there is no heat source unit 31 that can be started (ST42: No), the control device 50 stops the heat supply from the geothermal heat utilization system 1 to the device AA (ST47). After that, the user etc. considers maintenance of each device on the pumping well side, such as removing clogging of the screen of the pumping well.

[0098] (Operation of water level control of return well) The operation of the water level control of the return well will now be described.

[0099] When the geothermal energy utilization system 1 is started, the return water level acquisition unit 516 acquires the measurement result of the water level gauge 16 on the return well side as the return water level, and judges whether the acquired return water level is lower than a second limit water level (e.g., 25 m) (ST61), as shown in Fig. 9. For example, the second limit water level is a preset value. Here, the second limit water level that is set is a water level at which the flow rate of return water should be limited and the heat source unit 31 should be started when the water level reaches or exceeds this water level. In this water level control during cooling operation, the return well is the hot water well 11 and the pumping well is the cold water well 12. On the other hand, in this water level control during heating operation, the return well is the cold water well 12 and the pumping well is the hot water well 11.

[0100] In ST61, if it is determined that the acquired return water level is not lower than the second limit water level (determined to be above the second limit water level) (ST61: No), the heat source unit control unit 513 determines whether there is a heat source unit 31 (another heat source unit) that can be started among the multiple heat source units 31 (ST62).

[0101] In ST62, if it is determined that there is a heat source unit 31 that can be activated (ST62: Yes), the heat source unit control unit 513 activates the heat source unit 31 that can be activated (ST63), and the control device 50 returns to executing ST61. For example, in ST63, the heat source machine control unit 513 first starts one of the heat source machines 31 that can be started (setting can be changed). If there are multiple heat source machines 31 that can be started, the heat source machine control unit 513 can perform step-up / step-down control by repeating ST61 to ST63. At that time, the heat source machine control unit 513 may perform step-up / step-down control by checking the amount of heat or flow rate supplied to the device AA.

[0102] In addition, in ST63, the return water flow control unit 517 may control the return water flow rate to the return well by limiting the capacity of the submersible pump PP on the pumping well side or by stopping the operation of the submersible pump PP on the pumping well side. On the other hand, the flow control unit 512 may control the flow rate adjustment device 22 to reduce the flow rate FL so that the return water temperature of the heat source well facility 10 is within the allowable value, thereby suppressing the load on the heat source well facility 10. Furthermore, the flow rate control unit 512 may control the auxiliary flow rate adjustment device 33 to increase the flow rate of the heat medium flowing between the auxiliary heat supply facility 30 and the equipment AA.

[0103] In ST61, if it is determined that the obtained return water level is lower than the second limit water level (ST61: Yes), it is determined whether the obtained return water level is higher than a second release water level (for example, 21 m) (ST64). For example, the second release water level is a preset value. Here, the second release water level that is set is a water level below which the restriction on the flow rate of the return water should be released and the heat source unit 31 should be stopped. Moreover, in order to provide hysteresis between the start-up condition and the stop condition of the heat source unit 31, the second release water level is set lower than the second restriction water level.

[0104] In ST64, if it is determined that the acquired return water level is higher than the second release water level (ST64: Yes), the control device 50 determines that the return water restriction should not be released yet and returns to the execution of ST61.

[0105] In ST64, if the acquired return water level is not determined to be higher than the second release water level (determined to be lower than the second release water level) (ST64: No), there is a possibility that the return water restriction can be lifted, and the heat source machine control unit 513 determines whether or not there is any heat source machine 31 that is running among the multiple heat source machines 31 (heat source machines other than the heat source machines included in the heat source well equipment 10) (ST65).

[0106] If it is determined in ST65 that there is a heat source unit 31 that is running (ST65: Yes), the heat source unit control unit 513 stops the running heat source unit 31 (ST66), and the control device 50 returns to executing ST61. At that time, the return water flow rate control unit 517 may control the return water flow rate to the return well to be increased by removing the restriction imposed on the capacity of the submersible pump PP on the pumping well side or by starting the operation of the submersible pump PP on the pumping well side. On the other hand, the flow control unit 512 may control the flow control device 22 to increase the flow rate FL, and control the auxiliary flow control device 33 to decrease the flow rate of the heat medium flowing between the auxiliary heat supply equipment 30 and the equipment AA.

[0107] If it is determined in ST65 that there is no heat source unit 31 that is in operation (ST65: No), the control device 50 returns to the execution of ST61.

[0108] If it is determined in ST62 that there is no heat source unit 31 that can be started (ST62: No), the control device 50 stops the heat supply from the geothermal utilization system 1 to the device AA (ST67). After that, the user etc. considers maintenance of each device on the return well side, such as removing clogging of the return well screen.

[0109] (Action and Effects) According to this embodiment, the control device 50 controls the flow rate FL based on the return water temperature. Thereby, the control device 50 can limit the exhaust heat from the equipment AA to the heat source well facility 10 when the load heat quantity required by the equipment AA is large. Therefore, regardless of the heat load required by the equipment AA, the control device 50 can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return the groundwater to the return well. Therefore, the control device 50 is less likely to affect the underground environment.

[0110] As a comparative example, the geothermal energy utilization system disclosed in Patent Document 1 controls the return water temperature by controlling the flow rate from the pumping well to the return well. In this comparative geothermal energy utilization system, when the amount of heat discharged from the equipment to the aquifer is the same, the temperature difference between the pumping water temperature and the inlet water temperature is determined by the pumping water temperature and the set return water temperature, so only the flow rate is a variable value. For this reason, in the geothermal energy utilization system of the comparative example, the amount of water pumped is limited by the performance of the well, so if the load heat required by the equipment is large, the return water temperature will naturally exceed the upper limit (lower limit) even if the amount of water pumped is maximized. In addition, in the geothermal energy utilization system of the comparative example, the heat stored in the previous season is consumed toward the end of summer or winter, and the groundwater temperature approaches the initial groundwater temperature, reducing the available temperature difference. As a result, the return water temperature is likely to exceed the upper limit (lower limit) when the equipment is under high load. On the other hand, in a geothermal energy utilization system, it is desirable for the return water temperature to be a temperature that is unlikely to change the water quality of the aquifer; for example, it is desirable for the return water temperature to be a temperature that is unlikely to change the microbial community structure, etc. However, in the geothermal energy utilization system of the comparative example, the return water temperature can exceed the upper limit (lower limit), which can easily cause changes in the water quality of the aquifer. In response to this, the control device 50 controls the flow rate FL based on the return water temperature as described above, and therefore can adjust the groundwater temperature to a level that is less likely to affect the underground environment and return it to the return well, regardless of the load heat required by the equipment AA. Therefore, the control device 50 is less likely to cause changes to the water quality of the aquifer.

[0111] According to this embodiment, the control device 50 controls the start and stop of the heat source unit 31 based on the return water temperature, and therefore can start and stop the heat source unit 31 according to the load heat quantity required by the equipment AA. Thereby, when the load heat quantity required by the equipment AA is large, the control device 50 can cause the heat source well equipment 10 and the auxiliary heat supply equipment 30 to share the load heat quantity required by the equipment AA. Therefore, regardless of the heat load required by the equipment AA, the control device 50 can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return the groundwater to the return well. Therefore, the control device 50 is less likely to affect the underground environment.

[0112] For example, the control device 50 can control the start and stop of the heat source unit 31 based on the return water temperature, thereby allowing the load heat required by the equipment AA to be shared between the heat source well equipment 10 and the auxiliary heat supply equipment 30, as shown in Figure 10. As a result, the control device 50 basically operates the highly efficient heat source well equipment 10, and if the return water temperature exceeds the upper limit even when the pumping volume is maximized, it starts up a heat source unit 31 separate from the heat source well equipment 10 and controls (limits) the amount of heat discharged to the aquifer LY by allocating the load. Therefore, by controlling the start and stop of the heat source unit 31 based on the return water temperature as described above, the control device 50 can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well, regardless of the load heat required by the equipment AA. Therefore, the control device 50 is less likely to cause changes to the water quality of the aquifer.

[0113] According to this embodiment, when the geothermal energy utilization system 1 performs cooling operation on the equipment AA, the first stop temperature at which the heat source unit 31 should be stopped is lower than the first start-up temperature at which the heat source unit 31 should be started, so the control device 50 can impart hysteresis to the start-up conditions and stop conditions of the heat source unit 31. For example, the control device 50 can provide hysteresis to the start conditions and stop conditions of the heat source unit 31 as shown in FIG. Thereby, the control device 50 can suppress, for example, the oscillating operation of starting and stopping the heat source unit 31. Therefore, the control device 50 can stabilize the operation of the heat source unit 31.

[0114] According to this embodiment, when the geothermal energy utilization system 1 performs heating operation on the equipment AA, the second stop temperature at which the heat source unit 31 should be stopped is higher than the second start-up temperature at which the heat source unit 31 should be started, so the control device 50 can impart hysteresis to the start-up conditions and stop conditions of the heat source unit 31. Thereby, the control device 50 can suppress, for example, the oscillating operation of starting and stopping the heat source unit 31. Therefore, the control device 50 can stabilize the operation of the heat source unit 31.

[0115] According to this embodiment, the heat source unit control unit 513 can perform step-up / down control to start up a number of heat source units 31 corresponding to the load heat quantity shared by the auxiliary heat supply equipment among the load heat quantity required by the equipment AA. Therefore, the control device 50 can utilize the multiple heat source units 31 efficiently.

[0116] According to this embodiment, the pumping flow rate control unit 515 controls the pumping flow rate based on the pumping side water level. This enables the control device 50 to limit fluctuations in the water level of the pumping well, such as a drop in the water level of the pumping well caused by, for example, clogging of the screen of the pumping well. Therefore, the control device 50 can, for example, prevent breakdowns caused by dry running of the submersible pump PP of the pumping well and progression of clogging of the pumping well. Therefore, the control device 50 enables the geothermal energy utilization system 1 to be operated for a long period of time.

[0117] According to this embodiment, the heat source unit control unit 513 controls the start and stop of the heat source unit 31 based on the pumping-side water level. This allows the control device 50 to supplement the load heat quantity required by the equipment AA based on the pumping-side water level. Therefore, even if the heat source well equipment 10 alone cannot bear the heat load required by the equipment AA in order to maintain the pumping side water level, the control device 50 can share the heat load required by the equipment AA between the heat source well equipment 10 and the auxiliary heat supply equipment 30. Therefore, the control device 50 can control the geothermal energy utilization system 1 so as to supply the load heat quantity required by the equipment AA.

[0118] As a comparative example, in the geothermal energy utilization system disclosed in Patent Document 1, if the water is pumped at a rate exceeding the capacity of the heat source well, the water level on the pumping side will drop significantly, which may cause the submersible pump PP to run dry or cause the screen on the pumping side to become clogged due to an increase in the flow rate passing through the screen. For example, when a heat source well is constructed, an upper limit on the amount of water pumped is determined through pumping tests, etc.; however, due to deterioration over time, such as clogging of the screen, there may be large fluctuations in the water level even with the same amount of water pumped. Therefore, it is desirable to limit the amount of water pumped based on the water level and to utilize a separate heat source. On the other hand, for example, when the heat source well equipment 10 is basically operated with high efficiency and the drop in water level on the pumping side exceeds a set value, the control device 50 can control the pumping flow rate and start up a heat source unit 31 separate from the heat source well equipment 10 to allocate the load. Therefore, the control device 50 can realize the limitation of the pumping amount and the utilization of another heat source based on the pumping-side water level.

[0119] According to this embodiment, the first release water level, at which the pumped water flow rate restriction should be lifted and the heat source unit 31 should be stopped, is higher than the first restriction water level, at which the pumped water flow rate should be restricted and the heat source unit 31 should be started, so the control device 50 can provide hysteresis to the start-up conditions and stop conditions of the heat source unit 31. For example, the control device 50 can provide hysteresis to the start conditions and stop conditions of the heat source unit 31 as shown in FIG. Thereby, the control device 50 can suppress, for example, the oscillating operation of starting and stopping the heat source unit 31. Therefore, the control device 50 can stabilize the operation of the heat source unit 31.

[0120] According to this embodiment, the pumped water flow rate control unit 515 controls the return water flow rate based on the return water side water level. This enables the control device 50 to limit fluctuations in the water level of the return well, such as a rise in the water level of the return well due to clogging of the screen of the return well. Therefore, the control device 50 can, for example, suppress the progression of clogging of the return well. Therefore, the control device 50 enables the geothermal energy utilization system 1 to be operated for a long period of time.

[0121] According to this embodiment, the heat source unit control unit 513 controls the start and stop of the heat source unit 31 based on the return water level. This allows the control device 50 to supplement the load heat quantity required by the equipment AA based on the return water level. Therefore, even if the heat source well equipment 10 alone cannot bear the heat load required by the equipment AA in order to maintain the return water level, the control device 50 can share the heat load required by the equipment AA between the heat source well equipment 10 and the auxiliary heat supply equipment 30. Therefore, the control device 50 can control the geothermal energy utilization system 1 so as to supply the load heat quantity required by the equipment AA.

[0122] As a comparative example, in the geothermal energy utilization system disclosed in Patent Document 1, if water is injected at a rate exceeding the capacity of the heat source well, the water level in the return well will rise significantly, and the flow rate through the return well screen will increase, which can lead to clogging. For example, when a heat source well is constructed, an upper limit on the amount of water returned is determined through return tests, etc.; however, due to deterioration over time, such as clogging of the screen, the water level may fluctuate greatly even with the same amount of water returned. Therefore, it is desirable to limit the amount of water returned based on the water level and to utilize a separate heat source. On the other hand, for example, when the heat source well equipment 10 is operated as a basically highly efficient system, and the water level rise in the return well exceeds a set value, the control device 50 can control the return water flow rate and start up a heat source unit 31 separate from the heat source well equipment 10 to allocate the load. Therefore, the control device 50 can realize the limitation of the return water amount and the utilization of another heat source based on the return water level.

[0123] According to this embodiment, the second release water level, at which the return water flow rate restriction should be lifted and the heat source unit 31 should be stopped, is lower than the second restriction water level, at which the return water flow rate should be restricted and the heat source unit 31 should be started, so the control device 50 can impart hysteresis to the start-up conditions and stop conditions of the heat source unit 31. Thereby, the control device 50 can suppress, for example, the oscillating operation of starting and stopping the heat source unit 31. Therefore, the control device 50 can stabilize the operation of the heat source unit 31.

[0124] According to this embodiment, the control device 50 uses the heat source well facility 10 and the auxiliary heat supply facility 30 in combination. For this reason, the heat source well equipment 10 is an equipment that treats the aquifer LY as a natural heat storage tank, and since it utilizes nature, there is a possibility of unforeseen circumstances occurring, whereas the control device 50 allows the auxiliary heat supply equipment 30 to serve as a backup for the heat source well equipment 10.

[0125] According to the control device 50 of this embodiment, automatic control of return water temperature management is easy, which makes management easier for users and allows the construction of a versatile system that makes it easy to utilize geothermal heat.

[0126] <Modification> In one example of the above-described embodiment, the control device 50 controls both the flow rate FL and the start and stop of the heat source unit 31 based on the return water temperature, but any control may be performed as long as the return water temperature can be controlled. As a modified example, if the control device 50 can control the return water temperature, it may control at least one of the flow rate FL based on the return water temperature and the start and stop of the heat source unit 31. In this case, the geothermal energy utilization system 1 may include at least one of the configurations of the flow rate adjustment device 22 and the auxiliary heat supply equipment 30.

[0127] In one example of the above-described embodiment, the auxiliary heat supply equipment 30 is equipped with multiple heat source units 31, but may include any device that can assist in at least one of the hot heat supply and cold heat supply provided by the heat source well equipment 10 to the equipment AA. As a modified example, the auxiliary heat supply equipment 30 may include one heat source unit 31 instead of the multiple heat source units 31 . As another modification, the auxiliary heat supply equipment 30 may include a cooling tower instead of or in addition to the multiple heat source units 31.

[0128] In one example of the above-described embodiment, the auxiliary heat supply equipment 30 is equipped with multiple heat source units 31, but may include any device that can assist in at least one of the hot heat supply and cold heat supply provided by the heat source well equipment 10 to the equipment AA. As a modified example, the auxiliary heat supply equipment 30 may include one heat source unit 31 instead of the multiple heat source units 31 . As another modification, the auxiliary heat supply equipment 30 may include a cooling tower instead of or in addition to the multiple heat source units 31.

[0129] In one example of the embodiment described above, the geothermal energy utilization circuit 20 includes a heat pump 21, but may be configured in any manner as long as it is capable of mediating and controlling the heat exchange between the heat exchanger 14 and the equipment AA. As a modified example, the geothermal heat utilization circuit 20 may include the flow rate control device 22 and the main pipe 23, and may not include the heat pump 21. In this case, the flow rate control device 22 may adjust the flow rate of the heat medium that flows directly from the device AA side of the heat exchanger 14 to the device AA.

[0130] In the example of the above-described embodiment, the upper limit (lower limit) of the return water temperature is set in advance, but the return water temperature may be set in any way as long as it can be controlled to a temperature that does not adversely affect the underground environment. As a variant example, since the upper limit (lower limit) of the return water temperature depends on the initial groundwater temperature in the area where the geothermal energy utilization system 1 is installed, the upper limit (lower limit) of the return water temperature in the control device 50 is not particularly limited and may be updated to an appropriate value that can be set as appropriate.

[0131] In the example of the embodiment described above, the flow rate control unit 512 controls the bypass valve 223, but any control may be performed as long as it can control the flow rate FL. As a modified example, in addition to or instead of controlling the bypass valve 223, the flow rate control unit 512 may control the flow rate FL by performing inverter control of the pump 221 or control of the opening degree of the motor-operated valve 222. Furthermore, similar to the control over the flow control device 22, the flow control unit 512 may adjust the flow rate of the medium flowing from the auxiliary heat supply equipment 30 to the equipment AA by controlling the opening degree of the bypass valve of the auxiliary flow control device 33, controlling the inverter of the pump of the auxiliary flow control device 33, and controlling the opening degree of the electric valve of the auxiliary flow control device 33.

[0132] In each of the above-mentioned embodiments, a program for realizing various functions of the control device 50 is recorded in a computer-readable recording medium, and the program recorded in the recording medium is read into a computer system and executed to perform various processes. Here, the various processes of the CPU 51 of the computer system are stored in a computer-readable recording medium in the form of a program, and the computer reads and executes the program to perform the various processes. The computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, and the like. The computer program may be distributed to a computer via a communication line or the like, and the computer that receives the program may execute the program.

[0133] <Other embodiments> Although the embodiment of the present disclosure has been described above, this embodiment is shown as an example and is not intended to limit the scope of the present disclosure. This embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the present disclosure. This embodiment and its modifications are included in the scope of the present disclosure and its equivalents, as well as in the scope and gist of the present disclosure.

[0134] <Additional Notes> The control device 50, the geothermal heat utilization system 1, the control method, and the program described in the above-described embodiment can be understood, for example, as follows.

[0135] (1) The control device 50 of the first embodiment includes a heat source well equipment 10 including a pumping well (cold water well 12 or hot water well 11), a return well (hot water well 11 or cold water well 12), well side piping 13 extending from the pumping well (cold water well 12 or hot water well 11) to the return well (hot water well 11 or cold water well 12), and a heat exchanger 14 provided in the middle of the well side piping 13, and a geothermal heat utilization system 1 including a geothermal heat utilization circuit 20 provided between the heat exchanger 14 and equipment AA, and includes a return water temperature acquisition unit 511 that acquires the return water temperature to the return water well (hot water well 11 or cold water well 12) of the geothermal heat utilization system 1, and a flow rate control unit 512 that controls the flow rate FL of the refrigerant flowing from the geothermal heat utilization circuit 20 to the equipment AA based on the return water temperature.

[0136] According to this embodiment, the control device 50 controls the flow rate FL based on the return water temperature. Thereby, the control device 50 can limit the exhaust heat from the equipment AA to the heat source well facility 10 when the load heat quantity required by the equipment AA is large. Therefore, regardless of the heat load required by the equipment AA, the control device 50 can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12). Therefore, the control device 50 is less likely to affect the underground environment.

[0137] (2) The control device 50 of the second aspect is the control device 50 of (1), which further includes an auxiliary heat supply equipment 30 provided in the equipment AA in parallel with the geothermal heat utilization circuit 20 and equipped with a heat source unit 31, and further includes a heat source unit control unit 513 that controls the start and stop of the heat source unit 31 based on the return water temperature.

[0138] According to this embodiment, the control device 50 can start and stop the heat source unit 31 according to the heat load required by the equipment AA. Thereby, when the load heat quantity required by the equipment AA is large, the control device 50 can cause the heat source well equipment 10 and the auxiliary heat supply equipment 30 to share the load heat quantity required by the equipment AA. Therefore, regardless of the heat load required by the equipment AA, the control device 50 can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12). Therefore, the control device 50 is less likely to affect the underground environment.

[0139] (3) The control device 50 of the third aspect is the control device 50 of (2) in which, when the geothermal energy utilization system 1 performs cooling operation on the equipment AA, the first stop temperature at which the equipment AA should be stopped is lower than the first start-up temperature at which the equipment AA should be started.

[0140] According to this aspect, the control device 50 can provide hysteresis to the start conditions and stop conditions of the heat source unit 31. Thereby, the control device 50 can suppress, for example, the oscillating operation of starting and stopping the heat source unit 31. Therefore, the control device 50 can stabilize the operation of the heat source unit 31.

[0141] (4) The control device 50 of the fourth aspect is a control device 50 of (2) or (3) in which, when the geothermal energy utilization system performs heating operation on the equipment AA, the second stop temperature at which the shutdown should be performed is higher than the second start-up temperature at which the startup should be performed.

[0142] According to this embodiment, hysteresis can be provided to the start and stop conditions of the device AA. This allows the control device 50 to suppress, for example, the oscillating operation of starting and stopping the device AA. Therefore, the control device 50 can stabilize the operation of the heat source unit 31.

[0143] (5) The control device 50 according to the fifth aspect is any one of the control devices 50 of (2) to (4), in which the heat source unit 31 is provided with a plurality of heat source units 31, and the heat source unit control unit 513 performs increase / decrease step control of the plurality of heat source units 31.

[0144] According to this embodiment, the control device 50 can start up the heat source units 31 in a number corresponding to the load heat quantity shared by the auxiliary heat supply equipment 30 out of the load heat quantity requested by the equipment AA. Therefore, the control device 50 can efficiently utilize the multiple heat source units 31.

[0145] (6) The control device 50 of the sixth aspect is the control device 50 of (1), further including a pumping side water level acquisition unit 514 that acquires the pumping side water level, which is the water level of the pumping well (cold water well 12 or hot water well 11), and a pumping flow rate control unit 515 that controls the pumping flow rate from the pumping well (cold water well 12 or hot water well 11) based on the pumping side water level.

[0146] According to this embodiment, the control device 50 controls the pumping flow rate based on the pumping-side water level. This enables the control device 50 to limit fluctuations in the water level in the pumping well (cold water well 12 or hot water well 11), such as a drop in the water level in the pumping well (cold water well 12 or hot water well 11) due to clogging of the screen of the pumping well (cold water well 12 or hot water well 11). Therefore, the control device 50 can, for example, prevent breakdowns due to dry running of the submersible pump PP of a pumping well (cold water well 12 or hot water well 11) and progression of clogging of the pumping well (cold water well 12 or hot water well 11). Therefore, the control device 50 enables the geothermal energy utilization system 1 to be operated for a long period of time.

[0147] (7) The control device 50 of the seventh aspect is the control device 50 of (6), in which the geothermal energy utilization system further includes an auxiliary heat supply equipment 30 equipped with a heat source unit 31 and arranged in parallel with the geothermal energy utilization circuit 20 in the equipment, and further includes a heat source unit control unit 513 that controls the start and stop of the heat source unit 31 based on the pumping side water level.

[0148] According to this embodiment, the control device 50 can supplement the load heat quantity required by the equipment AA based on the pumping-side water level. Therefore, even if the heat source well equipment 10 alone cannot bear the heat load required by the equipment AA in order to maintain the pumping side water level, the control device 50 can share the heat load required by the equipment AA between the heat source well equipment 10 and the auxiliary heat supply equipment 30. Therefore, the control device 50 can control the geothermal energy utilization system 1 so as to supply the load heat quantity required by the equipment AA.

[0149] (8) The control device 50 of the eighth aspect is the control device 50 of (1), further including a return water side water level acquisition unit 516 that acquires the return water side water level, which is the water level of the return water well (hot water well 11 or cold water well 12), and a return water flow rate control unit 517 that controls the return water flow rate to the return water well (hot water well 11 or cold water well 12) based on the return water side water level.

[0150] According to this embodiment, the pumped water flow rate control unit 515 controls the return water flow rate based on the return water side water level. This enables the control device 50 to limit fluctuations in the water level in the return well (hot water well 11 or cold water well 12), such as an increase in the water level in the return well (hot water well 11 or cold water well 12) due to clogging of the screen of the return well (hot water well 11 or cold water well 12). Therefore, the control device 50 can suppress the progression of clogging of, for example, the return well (the hot water well 11 or the cold water well 12). Therefore, the control device 50 enables the geothermal energy utilization system 1 to be operated for a long period of time.

[0151] (9) The control device 50 of the ninth aspect is the control device 50 of (8) in which the geothermal energy utilization system 1 further includes an auxiliary heat supply equipment 30 having a heat source unit 31 and provided in the equipment AA in parallel with the geothermal energy utilization circuit 20, and further includes a heat source unit control unit 513 that controls the start and stop of the heat source unit 31 based on the return water level.

[0152] According to this embodiment, the control device 50 can supplement the load heat quantity required by the equipment AA based on the return water level. As a result, even if the heat source well equipment 10 alone cannot bear the heat load required by equipment AA in order to maintain the return water level, the control device 50 can share the heat load required by equipment AA between the heat source well equipment 10 and the auxiliary heat supply equipment 30. Therefore, the control device 50 can control the geothermal energy utilization system 1 so as to supply the load heat quantity required by the equipment AA.

[0153] (10) The control device 50 of the tenth aspect includes a heat source well equipment 10 including a pumping well (cold water well 12 or hot water well 11), a return well (hot water well 11 or cold water well 12), a well side piping 13 extending from the pumping well (cold water well 12 or hot water well 11) to the return well (hot water well 11 or cold water well 12), and a heat exchanger 14 provided in the middle of the well side piping 13, a geothermal heat utilization system 1 including a geothermal heat utilization circuit 20 provided between the heat exchanger 14 and equipment AA, and an auxiliary heat supply equipment 30 provided in the equipment in parallel with the geothermal heat utilization circuit 20 and provided with a heat source unit 31, and includes a return water temperature acquisition unit 511 that acquires the return water temperature to the return well (hot water well 11 or cold water well 12) of the geothermal heat utilization system 1, and a heat source unit control unit 513 that controls the start and stop of the heat source unit 31 based on the return water temperature.

[0154] According to this embodiment, the control device 50 can start and stop the heat source unit 31 according to the heat load required by the equipment AA. Thereby, when the load heat quantity required by the equipment AA is large, the control device 50 can cause the heat source well equipment 10 and the auxiliary heat supply equipment 30 to share the load heat quantity required by the equipment AA. Therefore, regardless of the heat load required by the equipment AA, the control device 50 can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12). Therefore, the control device 50 is less likely to affect the underground environment.

[0155] (11) A geothermal energy utilization system 1 according to an eleventh aspect includes the control device 50 according to any one of (1) to (10), the heat source well facility 10, and the geothermal energy utilization circuit 20.

[0156] According to this embodiment, the geothermal utilization system 1 controls the flow rate FL based on the return water temperature. This allows the geothermal heat utilization system 1 to limit the exhaust heat from the equipment AA to the heat source well facility 10 when the load heat quantity required by the equipment AA is large. Therefore, regardless of the load heat required by equipment AA, the geothermal energy utilization system 1 can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12). Therefore, the geothermal energy utilization system 1 is less likely to affect the underground environment.

[0157] (12) A control method according to a twelfth aspect of the present invention obtains the return water temperature to the return well (hot water well 11 or cold water well 12) of a geothermal heat utilization system 1 including a heat source well equipment 10 including a pumping well (cold water well 12 or hot water well 11), a return well (hot water well 11 or cold water well 12), well side piping 13 extending from the pumping well (cold water well 12 or hot water well 11) to the return well (hot water well 11 or cold water well 12), and a heat exchanger 14 provided midway along the well side piping 13, and a geothermal heat utilization circuit 20 provided between the heat exchanger 14 and equipment AA, and controls the flow rate FL of the refrigerant flowing from the geothermal heat utilization circuit 20 to the equipment AA based on the return water temperature.

[0158] According to this aspect, the control method controls the flow rate FL based on the return water temperature. Thereby, the control method can limit the exhaust heat from the equipment AA to the heat source well facility 10 when the load heat quantity required by the equipment AA is large. Therefore, the control method can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12) regardless of the load heat required by the equipment AA. Therefore, the control method is less likely to affect the underground environment.

[0159] (13) A control method according to a thirteenth aspect of the present invention obtains the return water temperature to the return well (hot water well 11 or cold water well 12) of a geothermal heat utilization system 1 including a heat source well equipment 10 having a pumping well (cold water well 12 or hot water well 11), a return well (hot water well 11 or cold water well 12), well side piping 13 extending from the pumping well (cold water well 12 or hot water well 11) to the return well (hot water well 11 or cold water well 12), and a heat exchanger 14 provided midway along the well side piping 13, a geothermal heat utilization circuit 20 provided between the heat exchanger 14 and equipment AA, and an auxiliary heat supply equipment 30 provided in parallel with the geothermal heat utilization circuit 20 in the equipment AA and equipped with a heat source unit 31, and controls the start and stop of the heat source unit 31 based on the return water temperature.

[0160] According to this aspect, the control method can start and stop the heat source unit 31 according to the load heat quantity required by the device AA. As a result, in the control method, when the load heat quantity required by the equipment AA is large, the load heat quantity required by the equipment AA can be shared between the heat source well equipment 10 and the auxiliary heat supply equipment 30. Therefore, the control method can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12) regardless of the load heat required by the equipment AA. Therefore, the control method is less likely to affect the underground environment.

[0161] (14) The program relating to the fourteenth aspect causes a computer to acquire a return water temperature to the return well (hot water well 11 or cold water well 12) of a geothermal heat utilization system 1 including a heat source well equipment 10 including a pumping well (cold water well 12 or hot water well 11), a return well (hot water well 11 or cold water well 12), well side piping 13 extending from the pumping well (cold water well 12 or hot water well 11) to the return well (hot water well 11 or cold water well 12), and a heat exchanger 14 provided midway along the well side piping 13, and a geothermal heat utilization circuit 20 provided between the heat exchanger 14 and equipment AA, and controls a flow rate FL of refrigerant flowing from the geothermal heat utilization circuit 20 to the equipment AA based on the return water temperature.

[0162] According to this embodiment, the program controls the flow rate FL based on the return water temperature. This allows the program to limit the amount of heat exhausted from the equipment AA to the heat source well facility 10 when the load heat quantity required by the equipment AA is large. Therefore, regardless of the load heat required by the equipment AA, the program can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12). Therefore, the program is less likely to impact the underground environment.

[0163] (15) The program relating to the fifteenth aspect causes a computer to acquire the return water temperature to the return well (hot water well 11 or cold water well 12) of a geothermal heat utilization system 1 including a heat source well equipment 10 including a pumping well (cold water well 12 or hot water well 11), a return well (hot water well 11 or cold water well 12), well side piping 13 extending from the pumping well (cold water well 12 or hot water well 11) to the return well (hot water well 11 or cold water well 12), and a heat exchanger 14 provided in the middle of the well side piping 13, a geothermal heat utilization circuit 20 provided between the heat exchanger 14 and equipment AA, and an auxiliary heat supply equipment 30 provided in the equipment AA in parallel with the geothermal heat utilization circuit 20 and equipped with a heat source unit 31, and to control the start and stop of the heat source unit based on the return water temperature.

[0164] According to this embodiment, the program can start and stop the heat source unit 31 according to the heat load required by the device AA. As a result, when the load heat quantity required by the equipment AA is large, the program can cause the heat source well equipment 10 and the auxiliary heat supply equipment 30 to share the load heat quantity required by the equipment AA. Therefore, regardless of the load heat required by the equipment AA, the program can adjust the temperature of the groundwater to a temperature that is less likely to affect the underground environment and return it to the return well (hot water well 11 or cold water well 12). Therefore, the program is less likely to impact the underground environment. [Explanation of symbols]

[0165] 1. Geothermal energy utilization system 10 Heat source well equipment 11 Hot water wells (return wells or pumping wells) 12 Cold water wells (pumping wells or return wells) 13 Well side piping 14 Heat exchanger 15 Water temperature gauge 16 Water level gauge 20 Geothermal heat utilization circuit 21 Heat Pump 22 Flow rate adjustment device 23 Main Pipe 30 Auxiliary heat supply equipment 31 Heat source machine 32 Auxiliary piping 33 Auxiliary flow adjustment device 50 Control device 51 CPU 52 Memory 53 Communication Interface 54 Recording media 131 First end 132 Second end 221 Pump 222 Motor-operated valve 223 Bypass valve 511 Return water temperature acquisition section 512 Flow control section 513 Heat source unit control section 514 Pumping side water level acquisition unit 515 Pumping flow control unit 516 Return water side water level acquisition part 517 Return water flow rate control section AA equipment FL flow rate LY Aquifer PP Submersible Pump VA Water Inlet Valve VB Check valve

Claims

1. a return water temperature acquisition unit that acquires a return water temperature to the return well of a geothermal heat utilization system including a heat source well equipment including a pumping well, a return well, a well-side pipe extending from the pumping well to the return well, and a heat exchanger provided midway along the well-side pipe, and a geothermal heat utilization circuit provided between the heat exchanger and an equipment; a flow rate control unit that controls a flow rate of the refrigerant flowing from the geothermal heat utilization circuit to the equipment based on the return water temperature; Equipped Control device.

2. The geothermal heat utilization system further includes an auxiliary heat supply facility provided in the equipment in parallel with the geothermal heat utilization circuit and including a heat source device; The heat source unit may further include a heat source unit control unit that controls start and stop of the heat source unit based on the return water temperature. The control device according to claim 1 .

3. When the geothermal energy utilization system performs a cooling operation on the equipment, a first stop temperature at which the equipment should be stopped is lower than a first start temperature at which the equipment should be started. The control device according to claim 2.

4. When the geothermal energy utilization system performs a heating operation on the equipment, a second stop temperature at which the equipment should be stopped is higher than a second start temperature at which the equipment should be started. The control device according to claim 2.

5. The heat source machine includes a plurality of heat source machines, The heat source unit control unit controls the number of heat source units to increase or decrease the number of stages. The control device according to claim 2.

6. A pumping-side water level acquisition unit that acquires a pumping-side water level, which is the water level of the pumping well; A pumping flow rate control unit that controls the pumping flow rate from the pumping well based on the pumping-side water level; Further equipped The control device according to claim 1 .

7. The geothermal heat utilization system further includes an auxiliary heat supply facility provided in the equipment in parallel with the geothermal heat utilization circuit and including a heat source device; The heat source unit further includes a heat source unit control unit that controls start and stop of the heat source unit based on the pumping side water level. The control device according to claim 6.

8. A return water level acquisition unit that acquires a return water level, which is the water level of the return well; A return water flow rate control unit that controls the return water flow rate to the return well based on the return water side water level; Further equipped The control device according to claim 1 .

9. The geothermal heat utilization system further includes an auxiliary heat supply facility provided in the equipment in parallel with the geothermal heat utilization circuit and including a heat source device; The heat source unit further includes a heat source unit control unit that controls start and stop of the heat source unit based on the return water level. The control device according to claim 8.

10. a return water temperature acquisition unit that acquires the return water temperature to the return well of a geothermal energy utilization system comprising: a heat source well equipment including a pumping well, a return well, a well-side pipe extending from the pumping well to the return well, and a heat exchanger provided midway along the well-side pipe; a geothermal energy utilization circuit provided between the heat exchanger and an equipment; and an auxiliary heat supply equipment provided in parallel with the geothermal energy utilization circuit and provided on the equipment, the auxiliary heat supply equipment having a heat source unit; A heat source unit control unit that controls start and stop of the heat source unit based on the return water temperature; Prepare Control device.

11. A control device according to any one of claims 1 to 10; The heat source well facility; The geothermal heat utilization circuit; Equipped Geothermal energy utilization system.

12. Obtaining a return water temperature to the return well of a geothermal energy utilization system including a heat source well equipment including a pumping well, a return well, a well-side pipe extending from the pumping well to the return well, and a heat exchanger provided midway along the well-side pipe, and a geothermal energy utilization circuit provided between the heat exchanger and an equipment; The flow rate of the refrigerant flowing from the geothermal heat utilization circuit to the device is controlled based on the return water temperature. Control methods.

13. Obtaining a return water temperature to the return well of a geothermal energy utilization system including a heat source well equipment including a pumping well, a return well, a well-side pipe extending from the pumping well to the return well, and a heat exchanger provided in the middle of the well-side pipe, a geothermal energy utilization circuit provided between the heat exchanger and an equipment, and an auxiliary heat supply equipment provided in the equipment in parallel with the geothermal energy utilization circuit and including a heat source unit, The start and stop of the heat source unit are controlled based on the return water temperature. Control methods.

14. On the computer, Obtaining a return water temperature to the return well of a geothermal energy utilization system including a heat source well equipment including a pumping well, a return well, a well-side pipe extending from the pumping well to the return well, and a heat exchanger provided midway along the well-side pipe, and a geothermal energy utilization circuit provided between the heat exchanger and an equipment; a flow rate of the refrigerant flowing from the geothermal heat utilization circuit to the equipment is controlled based on the return water temperature; to carry out program.

15. On the computer, Obtaining a return water temperature to the return well of a geothermal energy utilization system including a heat source well equipment including a pumping well, a return well, a well-side pipe extending from the pumping well to the return well, and a heat exchanger provided in the middle of the well-side pipe, a geothermal energy utilization circuit provided between the heat exchanger and an equipment, and an auxiliary heat supply equipment provided in the equipment in parallel with the geothermal energy utilization circuit and including a heat source unit, Controlling start and stop of the heat source unit based on the return water temperature. to carry out program.

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