JP6207476B2 - Geothermal heat pump system - Google Patents

Description

  The present invention relates to a hybrid heat pump system using geothermal heat that uses geothermal heat to save energy.

Conventionally, various heat pump systems have been proposed as air conditioning systems that suppress energy consumption by performing cooling or heating using underground heat with little temperature change throughout the year (for example, Patent Documents 1 and 2). .
Among these, the heat pump system disclosed in Patent Document 1 includes a ground heat exchanger having circulating water piping disposed in the ground and using ground heat as a heat source, and air heat exchange using outside air as a heat source. Equipment efficiency is improved by properly using underground heat and outside air heat according to the outside air temperature.

  Moreover, the heat pump system disclosed in Patent Document 2 includes a ground heat exchanger and a water-cooled cooling tower, and either one of the ground heat exchanger and the cooling tower or these are connected in parallel or in series. By selecting the operation mode, the power consumption is reduced and the system is designed to save energy.

JP 2009-250555 A JP 2012-127573 A

The heat pump system disclosed in Patent Document 1 is a heat pump system in which heat exchange with the outside air is performed by an air heat exchanger, and in a cooling operation as compared with the heat pump system of Patent Document 2 including a cooling / heating tower. There is a problem of poor efficiency.
On the other hand, although the heat pump system disclosed in Patent Document 2 includes a cooling tower, since it is mainly made by paying attention to the refrigerator, the frost phenomenon of the cooling tower that occurs when heating operation is performed. Since it has not been studied, there is a possibility that continuous heating operation cannot be performed. Further, when a defrost heater generally used in an air conditioning system is provided in order to eliminate frost formation, there is a problem that energy saving of the system cannot be sufficiently achieved.

  Furthermore, in the heat pump system disclosed in Patent Document 2, as a specific example of the operation mode in which the underground heat exchanger and the cooling tower are connected in series, the cooling tower is disposed on the upstream side and the underground heat exchanger is disposed downstream. It is disclosed that it is arranged and operated on the side. However, in such an operation method, there is a problem that the temperature of the heat medium cannot be lowered efficiently when the outside air temperature is low during the cooling operation.

An object of the present invention is to provide a heat pump system using geothermal heat that can improve efficiency during cooling operation and heating operation.
Another object of the present invention is to provide a geothermal heat pump system capable of continuous operation during heating operation without increasing power consumption.

In order to achieve the above object, the present invention
A heat pump that compresses and expands the heat medium to transfer heat from the low-temperature part to the high-temperature part, a cooling / heating tower that collects or releases heat from the atmosphere, and a ground heat exchanger that uses ground heat as a heat source, A geothermal heat utilization heat pump system comprising secondary equipment that absorbs heat or dissipates heat in a space to be air-conditioned and control means that controls the operation of the system,
The control means includes
A first cooling mode in which cooling is performed by circulating a cooling fluid between the heat pump and the underground heat exchanger;
A second cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
A third cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower;
A first heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the underground heat exchanger;
A second heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
A third heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower;
Is configured to be controllable to switch to
The cooling mode is operated in the order of the first cooling mode, the second cooling mode, the third cooling mode,
The heating mode is operated in the order of the first heating mode, the second heating mode, and the third heating mode,
To change the cooling mode,
The temperature of the cooling fluid flowing into the underground heat exchanger and the temperature of the cooling fluid flowing out are determined depending on the difference between the temperatures,
To change the heating mode,
It is characterized by being performed according to the conditions of the temperature of the heat source fluid flowing into the underground heat exchanger and the temperature of the heat source fluid flowing out, and the difference between these temperatures.
The present invention also provides:
A heat pump that compresses and expands the heat medium to transfer heat from the low-temperature part to the high-temperature part, a cooling / heating tower that collects or releases heat from the atmosphere, and a ground heat exchanger that uses ground heat as a heat source, A geothermal heat utilization heat pump system comprising secondary equipment that absorbs heat or dissipates heat in a space to be air-conditioned and control means that controls the operation of the system,
The control means includes
A first cooling mode in which cooling is performed by circulating a cooling fluid between the heat pump and the underground heat exchanger;
A second cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
A third cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower;
A first heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the underground heat exchanger;
A second heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
A third heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower, and can be controlled to be switched .
The control means includes
In the second cooling mode, the cooling fluid that has passed through the underground heat exchanger is sent to the cooling / heating tower, and then the cooling fluid is circulated so as to be sent to the heat pump.
In the second heating mode, the heat source fluid that passes through the cooling / heating tower is sent to the underground heat exchanger, and then the heat source fluid is circulated so as to be sent to the heat pump.

According to the above-described means, since the cooling / heating tower is used not only during the cooling operation but also during the heating operation, a heat pump system with good energy efficiency can be realized. In addition, the number of U-shaped pipes that flow heat exchange wells and cooling / heat source fluids that make up the underground heat exchanger can be reduced, enabling significant cost reductions and using only cooling and heating towers. Therefore, it is possible to perform continuous operation for a long time because the cooling and heating operations and the cooling and heating operations using only the underground heat exchanger are possible.
Further, in the second cooling mode, the control means circulates the cooling fluid so as to send the cooling fluid that has passed through the underground heat exchanger to the cooling / heating tower and then to the heat pump, and In the heating mode, the heat source fluid that has passed through the cooling / heating tower is sent to the underground heat exchanger, and then the heat source fluid is circulated so as to be sent to the heat pump. Since the cooling unit becomes the upstream side in the circulation of the cooling fluid and the cooling / heating tower is the upstream side in the circulation of the heat source fluid during the heating operation, when the capacity of the underground heat exchanger is reduced, the cooling / heating source fluid is efficiently Cooling or heating can be performed. Further, it is possible to improve the energy efficiency by making the most effective use of the underground heat during the cooling operation, and it is possible to perform a stable heating operation for a long time during the heating operation.

Desirably, the cooling / heating tower cools the cooling fluid by vaporization heat in the second cooling mode and the third cooling mode, while the heat source fluid and the atmosphere are cooled in the second heating mode and the third heating mode. It is configured to collect heat by heat transfer between the two.
As a result, the cooling / heating tower can function as a water-cooled cooling tower, so that the capacity during cooling operation can be improved.

Further preferably, the control means includes:
In the second cooling mode, the cooling fluid is circulated in parallel to the underground heat exchanger and the cooling / heating tower.
As a result, the cooling fluid is circulated in parallel to the underground heat exchanger and the cooling / heating tower during cooling operation, so that depending on the outside air temperature conditions, the energy efficiency can be improved compared to the case where the cooling fluid is circulated in series. Is possible.

Preferably, the control means includes
In the second heating mode or the third heating mode, the temperature difference between the outlet temperature of the cooling / heating tower and the inlet temperature is not more than a predetermined value, and the inlet temperature of the cooling / heating tower is not more than a predetermined temperature. In addition, the first defrost mode in which the heat source fluid is circulated between the underground heat exchanger and the cooling / heating tower without sending the heat source fluid to the heat pump is configured to be executable.
According to this configuration, when the cooling / heating tower is frosted during the heating operation, defrosting can be performed using the underground heat without using a heater, so that power consumption is not increased. Energy efficiency can be improved and system efficiency can be increased.

Further preferably, the control means includes:
Even if the first defrost mode is executed for a predetermined time, the outlet temperature of the cooling / heating tower does not recover to a predetermined temperature or more, and the detected temperature difference between the inlet temperature and the outlet temperature of the cooling / heating tower is a predetermined value or more. In some cases, the second defrost mode in which the heat source fluid is circulated between the cooling / heating tower without stopping the operation of the heat pump and sending the heat source fluid of the heat pump to the secondary equipment can be executed. To do.
According to such a configuration, since the frosted state of the cooling / heating tower can be eliminated by using the residual heat of the heat pump, the time required for defrosting can be shortened.

Preferably, the control means includes
In the second heating mode or the third heating mode, the detected temperature difference between the outlet temperature of the cooling / heating tower and the inlet temperature is not more than a predetermined value, and the inlet temperature of the cooling / heating tower is not more than a predetermined temperature. When heating of the space to be air-conditioned is required, the heat source fluid is circulated between the heat pump and the underground heat exchanger to operate the heat pump, and the heat source fluid of the heat pump is transferred to the secondary side. You may comprise so that the 3rd defrost mode which circulates a heat source fluid between the said cooling and heating towers can be performed, heating to a cooling-heating target space, sending to an installation.
According to such a configuration, heating can be performed while defrosting is being performed, and the heating and air conditioning stop time can be shortened.

Further preferably, the control means includes:
Even if the second defrost mode is executed for a predetermined time, the outlet temperature of the cooling / heating tower does not recover to a predetermined temperature or more, and the detected temperature difference between the inlet temperature and the outlet temperature of the cooling / heating tower is a predetermined value or more. In some cases, the heat pump is operated by circulating a heat source fluid between the heat pump and the underground heat exchanger, and the cooling / heating is performed without sending the heat source fluid of the heat pump to the secondary equipment. A fourth defrost mode in which the heat source fluid is circulated with the tower is configured to be executable.
According to such a configuration, since the frosted state of the cooling / heating tower can be eliminated using the heat source fluid warmed by the heat pump, the time required for defrosting can be further shortened, and the heat pump and the underground heat exchange can be reduced. Since the heat pump is operated by circulating a heat source fluid to and from the container, it is possible to effectively use renewable energy.

  ADVANTAGE OF THE INVENTION According to this invention, the heat pump system using geothermal heat which can improve the energy efficiency at the time of air_conditionaing | cooling operation and heating operation is realizable. In addition, there is an effect that it is possible to realize a heat pump system using geothermal heat that can be continuously operated during heating operation without increasing power consumption.

It is a lineblock diagram showing one embodiment of a heat pump system using geothermal heat concerning the present invention. It is a flowchart which shows the procedure of the control at the time of the cooling operation in the heat pump system of embodiment of FIG. It is a flowchart which shows the procedure of the control at the time of the heating operation in the heat pump system of embodiment of FIG. It is a flowchart which shows the procedure of the control at the time of the heating operation in the heat pump system using geothermal heat of embodiment of FIG. 1, and the procedure of a defrost operation. It is a figure which shows the circulation path | route of the cold water and cooling water at the time of the ground-heat utilization cooling operation mode using only geothermal heat. It is a figure which shows the circulation path | route of the cold water and cooling water at the time of the hybrid cooling operation mode using a cooling and heating tower and a ground heat exchanger. It is a figure which shows the circulation path | route of the cold water and cooling water at the time of the cooling tower utilization cooling operation mode using only a cooling and heating tower. It is a figure which shows the circulation path | route of the cold water and cooling water at the time of the parallel cooling operation mode using a cooling and heating tower and an underground heat exchanger. It is a figure which shows the circulation path | route of the warm water and heat source water at the time of the underground heat utilization heating operation mode using only geothermal heat. It is a figure which shows the circulation path | route of the warm water and heat source water at the time of the hybrid heating operation mode using a cooling and heating tower and an underground heat exchanger. It is a figure which shows the circulation path | route of the warm water and heat source water at the time of heating tower utilization heating operation mode using only a cooling and heating tower. It is a figure which shows the circulation path | route of the heat source water at the time of defrost mode in the geothermal heat utilization heat pump system of embodiment of FIG. It is a flowchart which shows the procedure (first half) of the control at the time of the heating operation in the heat pump system using geothermal heat of 2nd Example. It is a flowchart which shows the procedure (second half) of the control at the time of heating operation in the heat pump system using the ground heat of 2nd Example, and the procedure of a defrost operation. It is a flowchart which shows the procedure (first half) of the defrost driving | operation in the geothermal heat utilization heat pump system of 2nd Example. It is a flowchart which shows the procedure (second half) of the defrost driving | operation in the geothermal heat utilization heat pump system of 2nd Example. It is a figure which shows the circulation path | route of the heat source fluid at the time of the 1st defrost mode in the heat pump system using the ground heat of 2nd Example. It is a figure which shows the circulation path | route of the heat source fluid at the time of the 2nd defrost mode in the heat pump system using the ground heat of 2nd Example. It is a figure which shows the circulation path | route of the heat source fluid at the time of the 3rd defrost mode in the heat pump system using the ground heat of 2nd Example. It is a figure which shows the circulation path | route of the heat source fluid at the time of the 4th defrost mode in the heat pump system using the ground heat of 2nd Example.

Hereinafter, embodiments of a heat pump system using ground heat according to the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of the entire geothermal heat pump system.
As shown in FIG. 1, the geothermal heat pump system according to this embodiment includes a heat pump (refrigerator) 10 that moves and transfers heat from a low temperature part to a high temperature part by compressing and expanding a heat medium, and collecting heat from the atmosphere. Alternatively, the cooling / heating tower 20 that radiates heat, the underground heat exchanger 30, the secondary equipment 40 that absorbs or radiates heat in the space to be air-conditioned, and control means (not shown) that controls the entire system. ing.

The heat pump 10 includes a compressor 11, a condenser 12, an evaporator 13, and the like. Since the functions and operations of the compressor 11, the condenser 12, and the evaporator 13 are the same as those of a general air conditioning system, detailed description thereof is omitted.
The cooling / heating tower 20 includes a cooling fan, and operates in a cooling operation mode as a heat exchanger in which the temperature of cooling water decreases due to latent heat of vaporization. In the heating operation mode, heat is collected by heat transfer, and the temperature of the heat source water It is comprised so that it may operate | move as a heat exchanger which rises. In the present embodiment, as the cooling / heat source water circulating through the cooling / heating tower 20, an antifreeze is used during heating operation. The cooling / heating tower 20 includes a defrost heater that eliminates frost formation during the heating operation in winter.

The underground heat exchanger 30 is a heat exchanger that uses underground heat as a heat source, and digs a vertical hole (heat exchange well) in the ground to circulate cooling and heat source water. The pipe 31 is disposed and then backfilled. As the underground heat exchanger 30, those having various structures have been proposed conventionally, and in the present invention, the underground heat exchanger having the same configuration as the conventionally proposed underground heat exchanger is used. Therefore, detailed description is omitted.
The piping connecting the heat pump 10, the cooling / heating tower 20, and the underground heat exchanger 30 is made of a relatively high heat insulating material, whereas the underground heat exchanger 30. The U-shaped pipe 31 is made of a material having high thermal conductivity.

The secondary side equipment 40 is an air conditioner that cools and heats the air conditioning target space. For example, the secondary side equipment 40 includes a water passage arranged in a meandering manner and has a surface covered with a panel. It can be constituted by a radiant panel (heat exchanger) having a function of cooling or warming air through the panel by flowing cold water during cooling and warm water during heating. It may be a device having the same configuration as an indoor unit of an air conditioner (so-called air han).
In addition, when using the underground heat utilization heat pump system which concerns on this invention as a snow melting apparatus, the secondary side equipment 40 is a heat exchanger for snow melting, and is set as the apparatus which has a structure and form suitable for snow melting. .

In the geothermal heat pump system of the present embodiment, a first feed pipe 61 and a first return pipe 62 that are disposed between the heat pump 10 and the underground heat exchanger 30 and through which cooling / heat source water flows are provided. A pump PM <b> 1 is provided in the middle of the first return pipe 62.
Further, between the heat pump 10 and the cooling / heating tower 20, a second feed pipe 63 branched from the middle of the first feed pipe 61 and a second return branched from the middle of the first return pipe 62. A pipe 64 is provided. Further, a first branch pipe 65 is provided between the first feed pipe 61 and the second return pipe 64, and a second branch pipe 66 is provided between the first return pipe 62 and the second feed pipe 63. ing.

Further, a third feed pipe 67 and a third return pipe 68 for circulating cold / hot water are provided between the heat pump 10 and the secondary equipment 40, and the pump PM2 is provided in the middle of the third return pipe 68. Is provided. Further, a first bypass pipe 71 and a second bypass pipe 72 are provided between the first feed pipe 61 and the third feed pipe 67, and a third pipe is provided between the first return pipe 62 and the third return pipe 68. A bypass pipe 73 and a fourth bypass pipe 74 are provided.
Further, a valve MV1 that is opened and closed by a drive source such as a solenoid or a motor is provided in the middle of the first feed pipe 61, and a valve MV2 is provided in the middle of the first return pipe 62. A valve MV3 is provided in the middle, and a valve MV4 is provided in the middle of the second return pipe 64. A valve MV5 is provided in the middle of the first branch pipe 65, a valve MV6 is provided in the middle of the second branch pipe 66, and a valve MV7 and a third return pipe 68 are provided in the middle of the third feed pipe 67. Is provided with a valve MV8. Further, a valve MV 9 is provided between the first feed pipe 61 and the first return pipe 62.

  Further, the valve MV11 is in the middle of the first bypass pipe 71, the valve MV12 is in the middle of the second bypass pipe 72, the valve MV14 is in the middle of the third bypass pipe 73, and the valve MV13 is in the middle of the fourth bypass pipe 74. Is provided. Further, a valve MV15 is provided between the branch point of the first feed pipe 61 and the first bypass pipe 71 and the branch point of the second bypass pipe 72, and the first return pipe 62 and the third bypass pipe 73 are provided. A valve MV16 is provided between the branch point of the second bypass pipe 74 and the branch point of the fourth bypass pipe 74. These valves MV1 to MV16 operate so as to block or allow the flow of cooling / heat source water or cold / hot water.

Further, a temperature sensor S1 for detecting the temperature of the cooling / heat source water is provided in the middle of the first feed pipe 61, and a temperature sensor S2 is provided in the middle of the first return pipe 62. A temperature sensor S3 is provided in the middle, and a temperature sensor S4 is provided in the middle of the second feed pipe 63.
The detection signals from the temperature sensors S1 to S4 are input to a control means (not shown), and the pump PM1 is controlled by a control signal output from the control means based on the operation mode and the detection signals from the temperature sensors S1 to S4. -PM2 is driven and controlled, and the valves MV1 to MV16 are controlled to open and close.
In addition, a temperature sensor is provided at the outlet of the evaporator 13, and the control means, based on the detection signal from this temperature sensor, the temperature at the outlet of the evaporator is, for example, −5 ° C. in the hybrid mode and the heating mode using the heating tower. The operation of the heat pump 10 is controlled so that the temperature at the outlet of the evaporator becomes a temperature such as 10 ° C., for example, in the geothermal heating mode.

The control means is composed of a CPU and a ROM for storing an operation program thereof, a RAM for providing a work area, etc., and a setting device such as a temperature switch and a mode switch for designating an operation mode, a cooling operation command switch, a heating operation command, or the like. A signal from a switch or the like is input, and a function of generating and outputting a control signal for controlling operations of the pumps PM1 to PM2 and valves MV1 to MV16 in the middle of the piping is provided.
The heat pump system using geothermal heat of the present embodiment is heated by the heating and cooling / heating tower 20 and the geothermal heat exchanger 30 with heat collected by the geothermal heat exchanger 30 in the winter heating operation mode. In addition to heating by heat, it is characterized in that heating only by the heat collected by the cooling / heating tower 20 is possible.

Further, in the cooling operation mode in summer, cooling by the cooling water radiated by the underground heat exchanger 30, cooling by the cooling water radiated by the cooling / heating tower 20 and the underground heat exchanger 30, and cooling / heating are performed. Cooling with the cooling water radiated by the tower 20 is possible. By adopting a configuration that enables cooling / heating using only the cooling / heating tower 20 in this way, for example, in the spring or autumn, when the outside air temperature is lower than the underground temperature, the cooling operation or the outside air temperature Heating operation is possible when the temperature is higher than the underground temperature, and energy efficiency is improved.
Further, in the heat pump system using geothermal heat of the present embodiment, defrosting operation that reduces power consumption of the heater and eliminates frost in the cooling / heating tower 20 during heating operation is possible. As a result, the system efficiency is higher than that of a conventional system that performs defrosting using only a heater.

  Further, as a feature of the heat pump system using geothermal heat of the present embodiment, in the cooling operation mode using the cooling water radiated by the cooling / heating tower 20 and the underground heat exchanger 30, the flow of the cooling water is exchanged with the ground heat. The heat exchanger 30 is in the order of the cooling / heating tower 20-the heat pump 10, that is, the underground heat exchanger 30 becomes an upstream exchanger, whereas the cooling / heating tower 20 and the underground heat exchanger 30 collect heat. In the heating operation mode by the heat, the cooling / heating tower 20-the underground heat exchanger 30-the heat pump 10 are in this order, that is, the cooling / heating tower 20 and the underground are improved so that the energy efficiency is improved by cooling and heating. It is characterized in that the order in which the cooling / heat source water flows through the heat exchanger 30 is determined. Thereby, compared with the case where the flow of cooling / heat source water is reversed, energy efficiency is improved.

  Next, the control method in each operation mode by the control means for realizing the above operation will be described with reference to the flowcharts of FIGS. 2 to 4, FIG. 2 is a control flow during cooling operation, FIG. 3 is a control flow during heating operation, and FIG. 4 is a control flow during heating operation and defrost operation. 5 to 8 show the circulation paths of the cooling water and the cold water in each mode during the cooling operation, and FIGS. 9 to 11 show the circulation paths of the heat source water and the hot water in each mode during the heating operation. Shows the circulation path of the heat source water in the defrost mode during heating operation.

As shown in FIG. 2, during cooling operation, the valves MV15, MV16; MV7, MV8 at the inlet / outlet of the condenser 12 and the evaporator 13 of the heat pump 10 are opened, and in the middle of the pipes 71-74 that bypass the heat pump 10. A certain valve MV11 to MV14 is closed (step S1). In this state, in order to start the underground heat utilization cooling mode using the underground heat exchanger 30, first, the valves MV1, 2 in the middle of the pipes 61, 62 connecting the heat pump 10 and the underground heat exchanger 30 are set. Opening and piping 63 to 6 toward the cooling / heating tower 20
6 and the valve MV9 between the first feed pipe 61 and the first return pipe 62 are closed (step S2).

  Then, the pump PM1 in the middle of the first return pipe 62 and the pump PM2 in the middle of the third return pipe 68 are rotated in a direction to send cooling water and cold water to the heat pump 10, respectively, and the heat pump 10 is cooled (step S3). ). Thereby, as shown in FIG. 5, the cooling along the path | route of heat pump 10 (condenser 12)-1st feed piping 61-underground heat exchanger 30-1st return piping 62-heat pump 10 (condenser 12). Circulation of water and the circulation of cold water along the path of the heat pump 10 (evaporator 13) -third feed pipe 67-2 secondary equipment 40-third return pipe 68-heat pump 10 (evaporator 13) are performed.

  Subsequently, the detection signals of the temperature sensor S1 for detecting the cooling water temperature of the first feed pipe 61 and the temperature sensor S2 for detecting the cooling water temperature of the first return pipe 62 are read, and the detected temperature of the sensor S2 is a predetermined temperature 1. It is determined whether it is higher than (eg, 32 ° C.) or whether the detected temperature difference T1-T2 between the sensors S1 and S2 is smaller than a predetermined temperature 2 (eg, 1.0 ° C.) (step S4). Here, when it is determined that the detected temperature T2 of the sensor S2 is lower than the predetermined temperature 1 or the detected temperature difference T1-T2 between the sensors S1 and S2 is larger than the predetermined temperature 2 (step S4: No), the process returns to step S2. The cooling operation of the heat pump 10 is continued.

  On the other hand, if it is determined in step S4 that the detected temperature T2 of the sensor S2 is higher than the predetermined temperature 1, or the detected temperature difference T1-T2 between the sensors S1 and S2 is smaller than the predetermined temperature 2 (step S4: Yes), step S5 In order to start the hybrid cooling mode using the cooling / heating tower 20 and the underground heat exchanger 30, the valves MV4 and MV6 in the middle of the pipes 64 and 66 toward the cooling / heating tower 20 are opened. The valve MV2 in the middle of the first return pipe 62 is newly closed, and the valves MV3, MV5, and MV9 are kept closed.

  In addition, the pump PM1 in the middle of the first return pipe 62 and the pump PM2 in the middle of the third return pipe 68 cause the cooling / heating tower 20 to perform the cooling operation while rotating in the direction in which the cooling water and the cold water are respectively sent to the heat pump 10 ( Step S6). Thereby, as shown in FIG. 6, heat pump 10 (condenser 12) -first feed pipe 61-ground heat exchanger 30-first return pipe 62-pipe 66-cooling / heating tower 20-pipe 64-heat pump. 10 (condenser 12) circulation of cooling water and heat pump 10 (evaporator 13) -third feed pipe 67-2 secondary equipment 40-third return pipe 68-heat pump 10 (evaporator 13) Cold water is circulated along the path.

As a result, it is determined that the capacity of the underground heat exchanger 30 has been reduced, and series operation is performed with the underground heat exchanger 30 as the upstream and the cooling / heating tower 20 as the downstream, and the capacity of the underground heat exchanger 30 is insufficient. Can be supplemented by the cooling / heating tower 20, and the cooling water temperature can be efficiently lowered to improve the efficiency of the heat pump.
Subsequently, it is determined whether or not the detected temperature difference T1-T2 between the temperature sensors S1 and S2 is smaller than a predetermined temperature 3 (for example, 0.5 ° C.) (step S7). Here, if it is determined that the detected temperature difference T1-T2 is larger than the predetermined temperature 3 (step S7: No), the process returns to step S5 to continue the hybrid cooling mode operation.

  On the other hand, if it is determined in step S7 that the detected temperature difference T1-T2 is smaller than the predetermined temperature 3 (step S7: Yes), the process proceeds to step S8, and the cooling mode using only the cooling / heating tower 20 is started. Therefore, the valve MV3 in the middle of the pipe 63 toward the cooling / heating tower 20 is opened, the valves MV1 and MV6 in the middle of the pipes 61 and 66 are switched from open to closed, and the valves MV2, MV5 and MV9 are kept closed. To do. Further, the pump PM1 in the middle of the first return pipe 62 and the pump PM2 in the middle of the third return pipe 68 are kept rotating in the direction in which the cooling water and the cold water are respectively sent to the heat pump 10.

Thereby, as shown in FIG. 7, the cooling water along the path | route of heat pump 10 (condenser 12)-2nd feed piping 63-cooling and heating tower 20-2nd return piping 64-heat pump 10 (condenser 12). And circulation of cold water along the path of the heat pump 10 (evaporator 13) -third feed pipe 67-2 secondary equipment 40-third return pipe 68-heat pump 10 (evaporator 13).
As a result, it is determined that the cooling capacity of the underground heat exchanger 30 has been lost, and only the cooling / heating tower 20 is operated, and the temperature of the underground heat can be recovered during this operation mode.
Thereafter, in step S9, it is determined whether or not a predetermined time (for example, 600 minutes) has elapsed. If it is determined that the predetermined time has not elapsed (step S9: No), the process proceeds to step S10 to determine whether or not the cooling switch is turned off, and it is determined that the cooling switch is not turned off (step S10: No). Then, it returns to step S8 and continues the cooling tower utilization air_conditioning | cooling mode driving | operation using only the cooling and heating tower 20. FIG.

On the other hand, if it is determined in step S9 that the predetermined time has passed (step S9: Yes), it is considered that the geothermal temperature has been recovered, and the process returns to step S2 to use the geothermal heat using only the geothermal heat exchanger 30. Start cooling mode.
Although not shown in FIG. 2, when it is determined that the outside air temperature is low and the system efficiency is high, as shown in FIG. 8, the cooling / heating tower 20 is operated as a cooling tower and the valve MV1 is operated. By opening MV4 and closing the valves MV5 and MV6, the cooling / heating tower 20 and the underground heat exchanger 30 are connected in parallel to execute the parallel cooling mode in which the cooling water is circulated. Also good. Thereby, cooling water temperature can be reduced efficiently and the efficiency of a heat pump can be improved.

  Next, a control method in the heating operation will be described. At the time of heating operation, as shown in FIG. 3, the inlet / outlet of the condenser 12 and the inlet / outlet of the evaporator 13 and the valves MV15, MV16; MV7, MV8 are closed and the valves MV11-MV in the middle of the bypass pipes 71-74 are closed. The MV 14 is opened (step S11). In this state, first, in order to start the geothermal heating mode using the underground heat exchanger 30, the valves MV1, 2 in the middle of the pipes 61, 62 connecting the heat pump 10 and the underground heat exchanger 30 are turned on. At the same time, the valves MV3 to MV6 and the valve MV9 between the first feed pipe 61 and the first return pipe 62 in the middle of the pipes 63 to 66 toward the cooling / heating tower 20 are closed (step S12).

  Then, the pump PM1 in the middle of the first return pipe 62 and the pump PM2 in the middle of the third return pipe 68 are rotated in the direction in which the heat source water and the hot water are respectively sent to the heat pump 10, and the heat pump 10 is heated (step S13). ). 9, the heat pump 10 (evaporator 13) -the bypass pipe 71-the first feed pipe 61-the ground heat exchanger 30-the first return pipe 62-the bypass pipe 73-the heat pump 10 (the evaporator) 13) Circulation of heat source water along the path of 13) and heat pump 10 (condenser 12) -bypass pipe 72-third feed pipe 67-2 secondary side equipment 40-third return pipe 68-bypass pipe 74-heat pump 10 (condensation) Hot water is circulated along the path of the vessel 12).

  Subsequently, the detection signals of the temperature sensor S1 for detecting the heat source water temperature of the first feed pipe 61 and the temperature sensor S2 for detecting the heat source water temperature of the first return pipe 62 are read, and the detection temperature T1 of the sensor S1 is a predetermined temperature. It is determined whether the temperature is lower than 4 (for example, 5 ° C.) or the detected temperature difference T2-T1 between the sensors S1 and S2 is smaller than a predetermined temperature 5 (for example, 1.0 ° C.) (step S14). If it is determined that the detected temperature T1 of the sensor S1 is higher than the predetermined temperature 4 or the detected temperature difference T2-T1 between the sensors S1 and S2 is higher than the predetermined temperature 5 (step S14: No), the process returns to step S12. The heating operation of the heat pump 10 is continued.

On the other hand, if it is determined in step S14 that the detected temperature T1 of the sensor S1 is lower than the predetermined temperature 4 or the detected temperature difference T2-T1 between the sensors S1 and S2 is smaller than the predetermined temperature 5 (step S14: Yes), step S15 In order to start the hybrid heating mode using the cooling / heating tower 20 and the underground heat exchanger 30, the valves MV3, MV5 in the middle of the pipes 63 and 65 toward the cooling / heating tower 20 are opened. The valve MV1 in the middle of the first feed pipe 61 is newly closed, the valves MV4, MV6, and MV9 are kept closed, and the MV2 is kept open. The pump PM1 in the middle of the first return pipe 62 and the pump PM2 in the middle of the third return pipe 68 heat the cooling / heating tower 20 while rotating the heat source water and the hot water in the direction to send the heat pump 10 to the heat pump 10, respectively. (Step S16).
Accordingly, as shown in FIG. 10, the heat pump 10 (evaporator 13) -the bypass pipe 71-the pipe 63-the cooling / heating tower 20-the pipe 65-the first feed pipe 61-the underground heat exchanger 30-the first return. Circulation of heat source water along the path of piping 62-bypass piping 73-heat pump 10 (evaporator 13) and heat pump 10 (condenser 12)-bypass piping 72-third feed piping 67-secondary side equipment 40-third Hot water is circulated along the path of return pipe 68-detour pipe 74-heat pump 10 (condenser 12).

As a result, it is judged that the capacity of the underground heat exchanger 30 has been lowered, and the cooling / heating tower 20 is operated upstream and the underground heat exchanger is operated downstream to cool the insufficient capacity of the underground heat exchanger. -While supplementing with the heating tower 20, a heat source water temperature can be raised efficiently and the efficiency of a heat pump can be improved.
Subsequently, the detection signals of the temperature sensor S4 for detecting the heat source water temperature of the second feed pipe 63 and the temperature sensor S3 for detecting the heat source water temperature of the second return pipe 64 are read, and the detected temperature difference between the temperature sensors S3 and S4 is read. It is determined whether T3-T4 is lower than a predetermined temperature 6 (for example, 1.0 ° C.) and the detected temperature T4 of the temperature sensor S4 is lower than a predetermined temperature 9 (for example, −7 ° C.) (step S17). If it is determined that the detected temperature difference T3-T4 is smaller than the predetermined temperature 6 and the detected temperature T4 is lower than the predetermined temperature 9 (step S17: Yes), the process proceeds to step S24 and the defrost mode is started (reference sign). C).

  On the other hand, if it is determined in step S17 that the detected temperature difference T3-T4 is larger than the predetermined temperature 6 or the detected temperature T4 is higher than the predetermined temperature 9 (step S17: No), the process proceeds to step S18, and the first feed The detection signals of the temperature sensor S1 for detecting the heat source water temperature of the pipe 61 and the temperature sensor S2 for detecting the heat source water temperature of the first return pipe 62 are read, and the detected temperature difference T2-T1 between the sensors S1 and S2 is a predetermined temperature 7 It is determined whether it is smaller than (for example, 1.0 ° C.). Here, if it is determined that the detected temperature difference T2-T1 between the sensors S1 and S2 is greater than the predetermined temperature 7 (step S18: No), the process returns to step S15 to continue the hybrid heating mode.

  If it is determined in step S18 that the detected temperature difference T2-T1 is smaller than the predetermined temperature 7 (step S18: Yes), the process proceeds to step S20 (reference A). And in order to start the heating tower utilization heating mode using only the cooling / heating tower 20, the underground heat exchange from the valve MV2 and the cooling / heating tower 20 in the middle of the return pipe 62 from the underground heat exchanger 30 is performed. The valve MV5 in the middle of the pipe 65 to the vessel 3 is closed, the valve MV4 in the middle of the return pipe 64 is switched from closed to open, the valves MV1, MV6, MV9 are kept closed, and the valve MV3 is kept opened. (Step S20). Further, the pump PM1 in the middle of the first return pipe 62 and the pump PM2 in the middle of the third return pipe 68 are kept rotating in the direction of sending the heat source water and the hot water to the heat pump 10, respectively.

Accordingly, as shown in FIG. 11, the heat pump 10 (evaporator 13) —the bypass pipe 71 —the second feed pipe 63 —the cooling / heating tower 20 —the second return pipe 64 —the bypass pipe 73 —the heat pump 10 (the evaporator 13). ) And heat pump 10 (condenser 12)-bypass pipe 72-third feed pipe 67-secondary side equipment 40-third return pipe 68-bypass pipe 74-heat pump 10 (condenser) The warm water is circulated along the route of 12).
As a result, it is determined that the heat collection capability of the underground heat exchanger 30 has been lost, and an operation using only the cooling / heating tower 20 is performed, and the temperature of the underground heat can be recovered during this operation mode.

  Next, whether or not the detected temperature difference T3-T4 between the temperature sensors S3 and S4 is smaller than a predetermined temperature 8 (eg, 1.0 ° C.) and the detected temperature T4 is lower than a predetermined temperature 9 (eg, 0 ° C.) in step S21. To determine. Here, if it is determined that the detected temperature difference T3-T4 is smaller than the predetermined temperature 8 and the detected temperature T4 is lower than the predetermined temperature 9 (step S21: Yes), the heating tower is frosted and the capacity is reduced. Therefore, the process proceeds to step S23 to execute the defrost operation.

If it is determined that the detected temperature difference T3-T4 is greater than the predetermined temperature 8 or the detected temperature T4 of the sensor S4 is higher than the predetermined temperature 9 (step S21: No), the process proceeds to step S22, and a predetermined time (for example, 600 minutes) is determined. And if it determines with predetermined time not having passed (step S22: No), it will progress to step 23, it will be determined whether the heating switch was turned off, and a heating switch is not turned off (step S23: No). If it determines, it will return to step S20 and the heating tower utilization heating mode operation | movement which uses only the cooling and heating tower 20 will be continued.
Moreover, if it determines with predetermined time having passed in step S22 (step S22: Yes), it will return to step S12 and will perform the geothermal utilization heating mode which uses the underground heat exchanger 30 (code | symbol B).

  On the other hand, when it is determined in step S21 that the detected temperature difference T3-T4 between the sensors S3 and S4 is smaller than the predetermined temperature 8 and the detected temperature T4 is lower than the predetermined temperature 9 (step S21: Yes), and the process proceeds to step S24. The valve MV2, MV5, and MV9 are opened, the valves MV4 and MV11 to MV14 are closed, and the pump PM1 is left driven, as shown in FIG. A defrost mode in which the heat source water is circulated with the intermediate heat exchanger 30 is executed. Accordingly, the heat source water along the path of the cooling / heating tower 20 -the pipe 65 -the first feed pipe 61 -the underground heat exchanger 30 -the first return pipe 62 -the valve MV9 -the pipe 63 -the cooling / heating tower 20 Circulation is performed, and the frosted state of the cooling / heating tower can be eliminated by using underground heat. At this time, the heater provided in the cooling / heating tower 20 may be energized to defrost using the heater together. As a result, the system efficiency can be increased as compared with the conventional method in which defrosting is performed using only the heater. Further, at the time of defrosting, the heat pump 10 and the pump PM2 are stopped (step S25). Thereby, power consumption can be further reduced.

In addition, after step S25, it transfers to step S26 and it is determined whether the detection temperature T3 of the temperature sensor S3 is higher than the predetermined temperature 10 (for example, 3 degreeC). If it is determined that the detected temperature T3 is lower than the predetermined temperature 10 (step S26: No), the process returns to step S24 and the defrost mode is continued. On the other hand, if it is determined in step S26 that the detected temperature T3 of the temperature sensor S3 at the heating tower outlet is higher than the predetermined temperature 10 (step S26: Yes), it can be considered that the frosted state of the heating tower has been eliminated. Therefore, it progresses to step S27 and it is determined whether it entered into the defrost mode of FIG. 4 according to the code | symbol C from step S17 in the hybrid heating mode of FIG.
If it is determined that the defrost mode has been entered from step S17 according to the symbol C (step S27: Yes), the procedure returns to step S15 of FIG. On the other hand, if it is determined in step S27 that the process has shifted from the step S21 to the defrost mode, that is, the defrost mode has not been entered according to the symbol C (step S27: No), the process returns to the step S20 and only the cooling / heating tower 20 is used. The heating tower using heating mode is executed. Also in this case, the hybrid heating mode using the cooling / heating tower 20 and the underground heat exchanger 30 may be executed by returning to step S15 (symbol D).

In the conventional cooling / heating system using a cooling / heating tower, when the cooling / heating tower is frosted, the water heated by the heater installed in the lower water tank is sprinkled on the piping surface of the heat exchanger of the cooling / heating tower. It was common to defrost by doing. However, this method requires extra energy. On the other hand, according to the said Example, since the frost formation of the cooling / heating tower 20 is eliminated using geothermal heat, there exists an advantage that the effective utilization of renewable energy is fully achieved.
In addition, since the method of defrosting with the warm water warmed by the conventional heater is to perform the sprinkling of warm water from the outside, it takes time to defrost, and the time for stopping the heating operation or reducing the performance becomes longer. There is a risk that frost cannot be thawed completely.

(Second embodiment)
Next, a second embodiment of the geothermal heat pump system to which the present invention is applied will be described. The defrost mode of the first embodiment described above is to eliminate the frost formation of the cooling / heating tower 20 by using the underground heat, but it takes time to defrost and the underground temperature decreases to some extent. It is considered that frost formation cannot be eliminated.
Therefore, in the second embodiment, a plurality of defrost modes are provided so that frost formation can be eliminated even if the underground temperature is lowered by a predetermined value or more. Specifically, the first embodiment has one defrost mode, whereas the second embodiment provides four patterns of defrost mode so that defrost (defrosting) is performed in a different manner depending on the state of frost formation. I made it.

  As shown in FIG. 17, the system of the second embodiment makes it possible to realize four types of defrost modes. Therefore, the second return pipe 64 and the third system are different from the system of the first embodiment shown in FIG. A pipe 75 connecting the return pipe 68 and a pipe 76 connecting the second feed pipe 63 and the third feed pipe 67 are added. The valve MV21 is provided in the middle of the pipe 75, and the valve MV22 is provided in the middle of the pipe 76. And a pump (referred to as a booster pump) PM3. Further, valves MV23 and MV24 are added in the middle of the third feed pipe 67 and the third return pipe 68, respectively.

In the second embodiment, the procedure of “cooling operation” (FIG. 2) and the circulation path of chilled water and cooling water (FIGS. 5 to 8) are the same as those of the first embodiment, and thus illustration and description thereof are omitted. .
13 and 14 show the procedure of the heating operation in the second embodiment. 3 and FIG. 4 showing the procedure of the heating operation in the second embodiment is that, when “YES” is determined in step S17 of FIG. 13 and step S21 of FIG. 14, the process proceeds to the defrost process S30 of FIG. 4. Instead of one type of defrost process in steps S24 to S27 in FIG. 4, one of the defrost modes # 1 to # 4 is executed according to the defrost process in steps S31 to S47 in FIGS.
FIG. 15 and FIG. 16 show the details of the defrost process (step S30 in FIG. 3) executed when the defrost condition (T3-T4 <predetermined temperature 6 and T4 <predetermined temperature 9) is satisfied during the hybrid heating mode. An example of a typical procedure is shown.

In the defrosting process of FIG. 15, it is first determined whether or not an air conditioning operation is necessary (for example, whether or not heating of the space to be air-conditioned is permitted) (step S31). If it is determined that the air conditioning operation is not required (step S31: No), the process proceeds to step S32, and it is determined whether or not priority is given to the energy saving operation (step S32). If it is determined that priority is given to energy saving operation (step S32: Yes), the process proceeds to step S33, and the valves MV1, MV4, MV6, MV11, MV14, MV21, MV22 are closed, and the valves MV2, MV3, MV5 and By opening MV9 and stopping the operation of heat pump 10 and cold / hot water pump PM2 and keeping pump PM1 driven (step S34), as shown in FIG. 17, cooling / heating tower 20 and underground heat exchange are performed. The defrost mode # 1 in which the heat source water is circulated with the vessel 30 is executed.
Accordingly, the heat source water along the path of the cooling / heating tower 20 -the pipe 65 -the first feed pipe 61 -the underground heat exchanger 30 -the first return pipe 62 -the valve MV9 -the pipe 63 -the cooling / heating tower 20 Circulation is performed, and the frosted state of the cooling / heating tower 20 can be eliminated by using the underground heat. This is the same processing as defrosting in steps S24 and S25 in the first embodiment.

  In step S35 following step S34, the detected temperature T3 of the temperature sensor S3 is higher than a predetermined temperature 10 (eg, 3 ° C.), or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is a predetermined temperature 11 (eg, 1 ° C.). Or less). Here, if it is determined that the detected temperature T3 is lower than the predetermined temperature 10 or the detected temperature difference T4-T3 is higher than the predetermined temperature 11 (step S35: No), it is said that the frosting of the cooling / heating tower has not been eliminated. Therefore, the process proceeds to step S36 to determine whether or not a predetermined time (for example, 5 minutes) has elapsed. If not, the process returns to step S33 to continue the defrost operation in mode # 1. Moreover, when it determines with predetermined time having passed by step S36, it transfers to following step S37 (defrost mode # 2 using the residual heat of a heat pump).

In step S35, it is determined that the detected temperature T3 of the temperature sensor S3 is higher than the predetermined temperature 10, or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is smaller than the predetermined temperature 11 (step S35: Yes). Then, since the frosting of the cooling / heating tower 20 has been eliminated, the process proceeds to step S47 in FIG. 16 according to the symbol E, and enters the defrost mode in FIG. 15 from step S17 in the hybrid heating mode in FIG. It is determined whether or not.
And if it determines with having entered into the defrost mode from step S17 (step S47: Yes), it will return to step S15 of FIG. 13 according to code | symbol D, and will perform hybrid heating mode. On the other hand, if it is determined in step S47 that the defrost mode has not been entered from step S17 (step S47: No), the process returns to step S20 in FIG. Run the heating mode. The determination of “No” in step S47 means that the defrost mode has been entered from step S21.

  In step S37 of the defrost mode # 2, the valves MV3 to MV6, MV23 and MV24 are closed, the valves MV12, MV13, MV21 and MV22 are opened, the operation of the heat pump 10 and the pumps PM1 and PM2 is stopped, and the pump PM3 Is driven (step S38), and hot water is circulated between the cooling / heating tower 20 and the heat pump 10 as shown in FIG. Accordingly, the hot water is circulated along the path of the cooling / heating tower 20 -pipe 76 -the fourth bypass pipe 74 -the heat pump 10 -the second bypass pipe 72 -the pipe 76 -the cooling / heating tower 20, and the heat pump 10 The frosted state of the cooling / heating tower 20 can be eliminated by using the hot water generated while heating.

  In step S39 following step S38, the detected temperature T3 of the temperature sensor S3 is higher than a predetermined temperature 12 (eg 3 ° C.), or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is a predetermined temperature 13 (eg 1 ° C.). Or less). Here, if it is determined that the detected temperature T3 is lower than the predetermined temperature 12 or the detected temperature difference T4-T3 is higher than the predetermined temperature 13 (step S39: No), the frosting of the cooling / heating tower 20 has not been eliminated. Therefore, the process proceeds to step S40 to determine whether or not a predetermined time (for example, 5 minutes) has elapsed. If not, the process returns to step S37 and the mode # 2 defrost operation is continued. Moreover, when it determines with predetermined time having passed by step S40, it transfers to following step S44 (Defrost mode # 4 using the hot water produced | generated by interrupting heating and operation | movement of a heat pump).

  In step S39, it is determined that the detected temperature T3 of the temperature sensor S3 is higher than the predetermined temperature 12, or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is smaller than the predetermined temperature 13 (step S39: Yes). Then, since it is that the frosting of the cooling / heating tower 20 has been eliminated, the process proceeds to step S47 in FIG. 16 according to the symbol E, and enters the defrost mode from step S17 (step S47: Yes). Returning to step S15 of FIG. 13 according to the symbol D, the hybrid heating mode is executed. Further, when the defrost mode is not entered from step S17 (from step S21), the process returns to step S20 in FIG. Run.

On the other hand, if it is determined in step S31 in FIG. 15 that the air-conditioning operation is necessary (step S31: Yes), the process proceeds to step S41, and the valves MV3 to MV6 and MV9 are closed and the valves MV1, MV2, and MV11 are closed. -MV14 and MV21-MV24 are opened, and booster pump PM3 is driven while heating operation of heat pump 10 is performed (step S42), thereby, as shown in FIG. 19, heat pump 10, secondary side equipment 40, and cooling / heating tower 20 Then, the defrost mode # 3 for circulating the hot water and the heat source water between the underground heat exchanger 30 is executed.
Thereby, circulation of the hot water from the heat pump 10 (condenser 12) to the secondary side equipment 40 and the cooling / heating tower 20 and circulation of the heat source water between the heat pump 10 (evaporator 13) and the underground heat exchanger 30 are performed. The frosted state of the cooling / heating tower 20 can be eliminated while heating is performed.

  In step S43 following step S42, the detected temperature T3 of the temperature sensor S3 is higher than a predetermined temperature 16 (eg, 10 ° C.), or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is a predetermined temperature 17 (eg, 1 ° C.). Or less). Here, if it is determined that the detected temperature T3 is lower than the predetermined temperature 16 or the detected temperature difference T4-T3 is higher than the predetermined temperature 17 (step S43: No), the frosting of the cooling / heating tower 20 has not been eliminated. Therefore, it returns to step S41 and continues the defrost driving | operation of mode # 3.

  In step S43, it is determined that the detected temperature T3 of the temperature sensor S3 is higher than the predetermined temperature 16, or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is smaller than the predetermined temperature 17 (step S43: Yes). Then, since it is that the frosting of the cooling / heating tower 20 has been eliminated, the process proceeds to step S47 in FIG. 16 according to the symbol E, and enters the defrost mode from step S17 (step S47: Yes). Returning to step S15 of FIG. 13 according to the symbol D, the hybrid heating mode is executed. Further, when the defrost mode is not entered from step S17 (from step S21), the process returns to step S20 in FIG. Run.

On the other hand, in the defrost mode # 4 of FIG. 16, first, in step S44, the valves MV3 to MV6, MV9 and MV23 and MV24 are closed, the valves MV1, MV2, MV11 to MV14, MV21 and MV22 are opened, and the heat pump 10 And by operating the booster pump PM3 (step S45), as shown in FIG. 20, the hot water and the heat source water are circulated from the heat pump 10 to the cooling / heating tower 20 and the underground heat exchanger 30.
Thereby, the heat source water is circulated between the heat pump 10, the cooling / heating tower 20, and the underground heat exchanger 30, and heating can be interrupted to eliminate the frosted state of the cooling / heating tower 20.

  In step S46 following step S45, the detected temperature T3 of the temperature sensor S3 is higher than a predetermined temperature 14 (for example, 10 ° C.), or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is a predetermined temperature 15 (for example, 1 ° C.). Or less). Here, if it is determined that the detected temperature T3 is lower than the predetermined temperature 14 or the detected temperature difference T4-T3 is higher than the predetermined temperature 15 (step S46: No), the frosting of the cooling / heating tower 20 has not been eliminated. Therefore, the process returns to step S44 to continue the defrosting operation in mode # 4.

  In step S46, it is determined that the detected temperature T3 of the temperature sensor S3 is higher than the predetermined temperature 14, or the detected temperature difference T4-T3 between the temperature sensors S3 and S4 is smaller than the predetermined temperature 15 (step S46: Yes). Then, since it means that the frosting of the cooling / heating tower 20 has been eliminated, the process proceeds to the next step S47 to enter the defrost mode from step S17 (step S47: Yes). Returning to step S15, the hybrid heating mode is executed. Further, when the defrost mode is not entered from step S17 (from step S21), the process returns to step S20 in FIG. Run.

As described above, in the second embodiment, since defrosting is not performed using the energy of electricity (for example, heater) or gas (for example, boiler), the renewable energy of ground heat and atmospheric heat is more effective. Can be used. Moreover, since warm water is supplied to the inside of the pipe, it is possible to defrost frost from the inside, and the time required for thawing or the performance degradation time can be shortened as compared with the watering method using warm water heated by the heater. Furthermore, since four types of defrost modes are provided and the mode is switched according to the state of frost formation, defrost can be performed efficiently.
In particular, modes # 1 and # 2 can be defrosted only by the transport power of the pump, and more effective use of renewable energy is possible. Moreover, if it is mode # 3, it is possible to continue heating air-conditioning, performing a defrost using geothermal heat. If it is mode # 4, heating air-conditioning stop time can be shortened.

Although the invention made by the present inventor has been specifically described based on the embodiment, the present invention is not limited to the embodiment. For example, in the above-described embodiment, the underground heat exchanger 30 has a structure in which a U-shaped pipe 31 is disposed by digging a vertical hole (heat exchange well) in the ground. It is also possible to use a structure in which a shallow hole is dug near the inner surface, and a pipe for circulating cooling and heat source water is arranged while being meandered in the lateral direction and backfilled. In the geothermal heat pump system according to the above-described embodiment capable of executing the hybrid heating mode using the cooling / heating tower 20 and the underground heat exchanger 30, the underground heat exchanger having such a structure is sufficient. Heating operation is possible, and this can reduce the cost required for manufacturing the underground heat exchanger.
In the above-described embodiment, the cooling / heating tower 20 is described as having a configuration in which cooling water is cooled by vaporization heat during cooling operation and heat is collected by heat transfer during heating operation. It is also possible to use a configuration that performs heat transfer during cooling operation as in heating operation.

In the embodiment, as shown in FIG. 8, a parallel cooling mode in which cooling water is circulated in parallel with respect to the cooling / heating tower 20 and the underground heat exchanger 30 during the cooling operation is executed. Although described as good, it is also possible to execute the parallel heating mode in which the heat source water is circulated in parallel with respect to the cooling / heating tower 20 and the underground heat exchanger 30 even during the heating operation.
Furthermore, in the above-described embodiment, the application to a geothermal heat pump system that performs cooling and heating has been described. However, the present invention can also be used for a system that melts snow (snow) such as railways and roads. it can. In this case, since the cooling operation mode is unnecessary, the cooling / heating tower does not need a cooling function, and it is desirable to design the structure so that the heat collection efficiency is good, thereby further improving the snow melting efficiency. Can be realized.

DESCRIPTION OF SYMBOLS 10 Heat pump 11 Compressor 12 Condenser 13 Evaporator 20 Cooling and heating tower 30 Ground heat exchanger 40 Secondary side equipment

Claims (8)

A heat pump that compresses and expands the heat medium to transfer heat from the low-temperature part to the high-temperature part, a cooling / heating tower that collects or releases heat from the atmosphere, and a ground heat exchanger that uses ground heat as a heat source, A geothermal heat utilization heat pump system comprising secondary equipment that absorbs heat or dissipates heat in a space to be air-conditioned and control means that controls the operation of the system,
The control means includes
A first cooling mode in which cooling is performed by circulating a cooling fluid between the heat pump and the underground heat exchanger;
A second cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
A third cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower;
A first heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the underground heat exchanger;
A second heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
A third heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower;
It is capable of controlling switched,
The cooling mode is operated in the order of the first cooling mode, the second cooling mode, the third cooling mode,
The heating mode is operated in the order of the first heating mode, the second heating mode, and the third heating mode,
To change the cooling mode,
The temperature of the cooling fluid flowing into the underground heat exchanger and the temperature of the cooling fluid flowing out are determined depending on the difference between the temperatures,
To change the heating mode,
A heat pump system using geothermal heat, which is performed according to the conditions of the temperature of the heat source fluid flowing into the ground heat exchanger, the temperature of the heat source fluid flowing out, and the difference between the temperatures . A heat pump that compresses and expands the heat medium to transfer heat from the low-temperature part to the high-temperature part, a cooling / heating tower that collects or releases heat from the atmosphere, and a ground heat exchanger that uses ground heat as a heat source, A geothermal heat utilization heat pump system comprising secondary equipment that absorbs heat or dissipates heat in a space to be air-conditioned and control means that controls the operation of the system,
  The control means includes
  A first cooling mode in which cooling is performed by circulating a cooling fluid between the heat pump and the underground heat exchanger;
  A second cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
  A third cooling mode for cooling by circulating a cooling fluid between the heat pump and the cooling / heating tower;
  A first heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the underground heat exchanger;
  A second heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower and the underground heat exchanger;
  A third heating mode in which heating is performed by circulating a heat source fluid between the heat pump and the cooling / heating tower;
Is configured to be controllable to switch to
  The control means includes
  In the second cooling mode, the cooling fluid that has passed through the underground heat exchanger is sent to the cooling / heating tower, and then the cooling fluid is circulated so as to be sent to the heat pump.
  In the second heating mode, the heat source fluid that passes through the cooling / heating tower is sent to the underground heat exchanger, and then the heat source fluid is circulated so as to be sent to the heat pump. . The cooling / heating tower cools the cooling fluid by the heat of vaporization in the second cooling mode and the third cooling mode, while transferring heat between the heat source fluid and the atmosphere in the second heating mode and the third heating mode. The ground heat utilization heat pump system according to claim 1 , wherein the heat pump system is configured to collect heat at a temperature. The control means includes
2. The geothermal heat pump system according to claim 1, wherein in the second cooling mode, a cooling fluid is circulated in parallel to the underground heat exchanger and the cooling / heating tower. The control means includes
In the second heating mode or the third heating mode, the detected temperature difference between the outlet temperature of the cooling / heating tower and the inlet temperature is not more than a predetermined value, and the inlet temperature of the cooling / heating tower is not more than a predetermined temperature. In this case, the first defrost mode in which the heat source fluid is circulated between the underground heat exchanger and the cooling / heating tower without sending the heat source fluid to the heat pump can be executed. The underground heat utilization heat pump system in any one of Claims 1-4. The control means includes
Even if the first defrost mode is executed for a predetermined time, the outlet temperature of the cooling / heating tower does not recover to a predetermined temperature or more, and the detected temperature difference between the inlet temperature and the outlet temperature of the cooling / heating tower is a predetermined value or more. In some cases, the second defrost mode in which the heat source fluid is circulated between the cooling / heating tower without stopping the operation of the heat pump and sending the heat source fluid of the heat pump to the secondary equipment can be executed. The heat pump system using geothermal heat according to claim 5, wherein The control means includes
In the second heating mode or the third heating mode, the detected temperature difference between the outlet temperature of the cooling / heating tower and the inlet temperature is not more than a predetermined value, and the inlet temperature of the cooling / heating tower is not more than a predetermined temperature. When heating of the space to be air-conditioned is required, the heat source fluid is circulated between the heat pump and the underground heat exchanger to operate the heat pump, and the heat source fluid of the heat pump is transferred to the secondary side. The third defrost mode in which the heat source fluid is circulated with the cooling / heating tower while being sent to the facility to heat the cooling / heating target space is configured to be executable. A heat pump system using geothermal heat according to any one of the above. The control means includes
Even if the second defrost mode is executed for a predetermined time, the outlet temperature of the cooling / heating tower does not recover to a predetermined temperature or more, and the detected temperature difference between the inlet temperature and the outlet temperature of the cooling / heating tower is a predetermined value or more. In some cases, the heat pump is operated by circulating a heat source fluid between the heat pump and the underground heat exchanger, and the cooling / heating is performed without sending the heat source fluid of the heat pump to the secondary equipment. The ground heat utilization heat pump system according to claim 6, wherein the fourth defrost mode in which the heat source fluid is circulated with the tower is executable.

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