JP6574393B2 - Combined heat source heat pump device - Google Patents

Description

  The present invention relates to a combined heat source heat pump apparatus that can supply a circulating fluid that has been subjected to heat exchange to a refrigerant in a heat pump circuit after heat exchange with a heat medium or outdoor air in a heat source connection path to a load terminal, and that can perform air conditioning. .

  Conventionally, in this type of combined heat source heat pump apparatus, as described in Patent Document 1, when using a heat pump circuit that exchanges heat with a heat medium and a heat pump circuit that exchanges heat with outdoor air, the outside air temperature and the reference temperature are By comparison, some compressors of one heat pump circuit are used as a main power source, and the compressor of the other heat pump circuit is switched as an auxiliary power source to control driving.

Japanese Patent Laying-Open No. 2015-117880

  In this conventional system, the heat pump circuit that exchanges heat with the heat medium exceeds the assumed operation amount depending on the outside air temperature and the load condition only by the simple switching between the main and auxiliary due to the high / low outside air temperature as described above. However, the temperature recovery of the heat source may be hindered or the efficiency of the heat pump circuit may be reduced.

In order to solve the above problems, in claim 1 of the present invention, the first compressor, the first load side heat exchanger, and the first heat source side heat exchanger are connected by a first refrigerant pipe, and A first heat source side heat exchanger and a predetermined heat source are connected by a heat medium pipe to form a first heat pump circuit, and a second compressor, a second load side heat exchanger, and a second heat exchanger that can exchange heat with outside air. 2 heat source side heat exchangers are connected by a second refrigerant pipe to form a second heat pump circuit, and the first load side heat exchanger, the second load side heat exchanger, and the load terminal are connected to the first heat pump circuit. Outside air temperature detection that detects the outside air temperature by forming a load side circuit by connecting the load side heat exchanger with the circulating fluid piping while being arranged in series upstream of the second load side heat exchanger. And the outside temperature detected by the outside temperature detecting means during operation is equal to a predetermined reference temperature. In a combined heat source heat pump device having control means for switching which one of the first compressor and the second compressor as a main power source and which as an auxiliary power source, depending on whether it is higher or lower, In the first heat pump circuit, provided is a refrigerant temperature detecting means for detecting a refrigerant temperature flowing into the first heat source side heat exchanger or flowing out of the first heat source side heat exchanger, and the control means includes: During cooling operation, if the outside air temperature detected by the outside air temperature detecting means is lower than the first reference temperature, the second compressor is used as a main power source and the first compressor is used as an auxiliary power source. When the outside air temperature detected by the outside air temperature detecting means is higher than the first reference temperature, the first compressor is used as a main power source and the second compressor is used as an auxiliary power source. While moving, the refrigerant temperature detected by the coolant temperature detecting means is intended to reduce the rotational speed of the first compressor When higher than the first threshold value.

According to a second aspect of the present invention, the load side circuit further includes a circulating fluid temperature detecting means for detecting a circulating fluid temperature flowing into the load side heat exchanger, and the control means is detected by the refrigerant temperature detecting means. The circulating fluid temperature detected by the circulating fluid temperature detecting means is lower than the first target temperature in a state where the refrigerant temperature is higher than the first threshold value and the rotational speed of the first compressor is reduced. When it becomes higher, the rotational speed of the second compressor is increased .

In order to solve the above problem, in claim 3 of the present invention , the first compressor, the first load side heat exchanger, and the first heat source side heat exchanger are connected by a first refrigerant pipe, and A first heat source side heat exchanger and a predetermined heat source are connected by a heat medium pipe to form a first heat pump circuit, and a second compressor, a second load side heat exchanger, and a second heat exchanger that can exchange heat with outside air. 2 heat source side heat exchangers are connected by a second refrigerant pipe to form a second heat pump circuit, and the first load side heat exchanger, the second load side heat exchanger, and the load terminal are connected to the first heat pump circuit. Outside air temperature detection that detects the outside air temperature by forming a load side circuit by connecting the load side heat exchanger with the circulating fluid piping while being arranged in series upstream of the second load side heat exchanger. And the outside temperature detected by the outside temperature detecting means during operation is equal to a predetermined reference temperature. In the composite heat source heat pump device having a control means for switching which one of the first compressor and the second compressor is used as a main power source and which is used as an auxiliary power source according to whether the power is higher or lower, In the first heat pump circuit, there is provided refrigerant temperature detection means for detecting a refrigerant temperature flowing into the first heat source side heat exchanger or flowing out of the first heat source side heat exchanger, and the control means includes heating During operation, when the outside air temperature detected by the outside air temperature detecting means is higher than a second reference temperature, the second compressor is driven as a main power source and the first compressor is driven as an auxiliary power source. When the outside air temperature detected by the outside air temperature detecting means is lower than the second reference temperature, the first compressor is used as a main power source and the second compressor is used as an auxiliary power source. As well as, the refrigerant temperature detected by the coolant temperature detecting means is intended to reduce the rotational speed of the first compressor When lower than the second threshold value.

According to a fourth aspect of the present invention, the load side circuit further includes a circulating fluid temperature detecting means for detecting a circulating fluid temperature flowing into the load side heat exchanger, and the control means is detected by the refrigerant temperature detecting means. The circulating fluid temperature detected by the circulating fluid temperature detecting means is lower than the second target temperature in a state where the refrigerant temperature is lower than the second threshold value and the rotational speed of the first compressor is reduced. If it becomes low, the rotation speed of the second compressor is increased.

  According to claim 1 of the present invention, two heat pump circuits capable of collecting or radiating heat from different heat sources are provided. The first heat pump circuit includes a predetermined heat source, a first heat source side heat exchanger, a first compressor, and a first load side heat exchanger, and the second heat pump circuit includes outside air as a heat source. A second heat source side heat exchanger capable of heat exchange, a second compressor, and a second load side heat exchanger are provided. At this time, the first load-side heat exchanger and the second load-side heat exchanger are connected to a load-side circuit through which the circulating fluid piping circulates, and the upstream side first load-side heat exchanger is connected to the first heat pump circuit side. After the heat exchange with the circulating fluid, the circulating fluid exchanged with the second heat pump circuit side by the second load side heat exchanger on the downstream side is supplied to the load terminal.

  Thus, in the load side circuit which can perform both the heat exchange in the first load side heat exchanger and the heat exchange in the second load side heat exchanger, based on the outside air temperature detected by the outside air temperature detecting means. The control means switches which heat exchange is the main and which heat exchange is the auxiliary. For example, at the time of cooling operation, when the outside air temperature is low, large heat radiation to the outside air can be expected. Therefore, the second compressor is driven as a main power source, and the first compressor is driven as an auxiliary power source. On the other hand, when the outside air temperature is high, the first compressor is driven as a main power source and the second compressor is driven as an auxiliary power source because heat radiation to the outside air cannot be expected so much. For example, when the outside air temperature is high during heating operation, the second compressor is driven as a main power source because the second heat source side heat exchanger hardly frosts even if heat is absorbed from the outside air. One compressor is driven as an auxiliary power source. On the other hand, when the outside air temperature is low, there is a problem that the second heat source side heat exchanger is frosted by absorbing heat from the outside air, so the first compressor is driven as a main power source and the second compression is performed. The machine is driven as an auxiliary power source.

  However, with only the simple switching between main and auxiliary due to the high and low outside air temperature as described above, the first heat pump circuit exceeds the assumed operation amount depending on the outside air temperature and load conditions, and the temperature recovery of the heat source is hindered. The first heat pump circuit may be reduced in efficiency.

  Therefore, according to the first aspect, the refrigerant temperature detection means is provided, and the refrigerant temperature flowing out from the first heat source side heat exchanger (during cooling) in the first heat pump circuit or to the first heat source side heat exchanger is provided. The refrigerant temperature that flows in (during heating) is detected. And the said control means reduces the rotation speed of a said 1st compressor according to the magnitude of the detected said refrigerant | coolant temperature and a predetermined threshold value.

  For example, during the cooling operation, when the detected refrigerant temperature becomes higher than a predetermined threshold value (first threshold value), the rotational speed of the first compressor is reduced. Accordingly, it is possible to suppress the first heat pump circuit from operating excessively in a state where the outside air temperature is high and the first compressor is driven as a main power source.

  Further, for example, during the heating operation, when the detected refrigerant temperature becomes lower than a predetermined threshold value (second threshold value), the rotational speed of the first compressor is reduced. Accordingly, it is possible to suppress the first heat pump circuit from operating excessively in a state where the outside air temperature is low and the first compressor is driven as a main power source.

As described above, according to the first aspect, since the first heat pump circuit can be prevented from operating excessively even during the cooling operation and the heating operation, the efficiency of the first heat pump circuit is always kept high. Can do. Further, since the first heat pump circuit can be prevented from exceeding the assumed operation amount, the temperature recovery of the heat source is not hindered, and the temperature recovery can be accelerated.
Further, according to the first aspect, during the cooling operation, when the outside air temperature is high, the first compressor is driven as a main power source, so that a large heat radiation amount to the heat source by the first heat pump circuit can be obtained. It can be ensured, and the first heat pump circuit can be prevented from operating excessively at that time. As a result, the efficiency of the first heat pump circuit can be reliably kept high during the cooling operation.

According to claim 2, the circulating fluid temperature detecting means is provided, and the rotational speed of the second compressor on the second heat pump circuit side is controlled to increase according to the detected circulating fluid temperature value. As a result, the second heat pump circuit side compensates for the decrease in the heat exchange amount between the first heat pump circuit side and the load side circuit due to the rotation speed reduction control of the first compressor executed by the control means, and the entire apparatus It is possible to prevent the cooling output (or heating output) from decreasing.
Furthermore, according to claim 2, an increase in the circulating fluid temperature due to a decrease in the amount of heat exchange between the first heat pump circuit side and the load side circuit is suppressed by heat radiation from the load side circuit to the second heat pump circuit. Thus, it is possible to prevent the cooling output of the entire apparatus from being lowered.

According to claim 3 of the present invention, during the heating operation, when the outside air temperature is low, the first compressor is driven as a main power source so that the first heat pump circuit can The amount of heat absorption can be ensured, and at that time, the first heat pump circuit can be prevented from operating excessively. As a result, the efficiency of the first heat pump circuit can be reliably kept high during the heating operation.

According to a fourth aspect of the present invention, a decrease in the circulating fluid temperature due to a decrease in heat exchange between the first heat pump circuit side and the load side circuit is suppressed by heat radiation from the second heat pump circuit to the load side circuit. Thus, it is possible to prevent the heating output of the entire apparatus from being lowered.

1 is an external configuration diagram of main units of a heat pump apparatus according to an embodiment of the present invention. Circuit diagram of the entire heat pump device The figure explaining the action at the time of cooling operation The figure explaining the action at the time of heating operation Functional configuration diagram of underground heat control device and air heat control device during cooling operation Functional configuration diagram of underground heat control device and air heat control device during heating operation The figure explaining switching of the main power source and auxiliary power source at the time of cooling operation, and the figure explaining switching of the main power source and auxiliary power source at the time of heating operation Explanatory diagram showing the effect of combined operation of main power source / auxiliary power source Explanatory drawing showing the behavior of the condenser outlet refrigerant temperature and underground temperature when reducing the rotation speed of the first compressor during cooling operation Explanatory drawing showing the behavior of the evaporator inlet refrigerant temperature and the underground temperature when the rotation speed of the first compressor is reduced during heating operation Diagram showing behavior of heat pump device during cooling operation The figure showing the behavior of the heat pump device during heating operation The flowchart figure showing the control procedure which a switching control part performs in cooperation at the time of air_conditionaing | cooling operation The flowchart figure showing the control procedure which a switching control part performs in cooperation at the time of heating operation

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an external configuration of a main unit of the heat pump apparatus 1 of the present embodiment to which the composite heat source type heat pump apparatus of the present invention is applied. In FIG. 1, the heat pump device 1 of the present embodiment is a load-side circuit that circulates a circulating liquid L (for example, water or antifreeze liquid) through the ground heat pump unit 4, the air heat pump unit 5, and the heat exchange terminal 36. Terminal circulation circuit 30 and underground heat circulation circuit 20.

  FIG. 2 shows a circuit configuration of the entire heat pump apparatus 1 of the present embodiment. As shown in FIG. 2, the heat pump device 1 is provided in the geothermal heat pump unit 4 and can heat or cool the circulating liquid L on the heat exchange terminal 36 side using a geothermal heat source. Air as a second heat pump circuit provided in the underground heat pump circuit 40 as a circuit and the air heat heat pump unit 5 and capable of heating or cooling the circulating liquid L on the heat exchange terminal 36 side using an air heat source. It has a thermal heat pump circuit 50, the terminal circulation circuit 30, and the underground heat circulation circuit 20 as a first heat pump circuit.

  In FIG. 2, the underground heat pump circuit 40 includes a variable capacity first compressor 43, a first heat exchanger 41 as a first load side heat exchanger, a first expansion valve 44, and a first heat source side. A ground heat source heat exchanger 45 as a heat exchanger is connected in an annular shape by a first refrigerant pipe 42. The first refrigerant pipe 42 is provided with a four-way valve 46 as a switching valve for switching the flow direction of the first refrigerant C1 (see FIGS. 3 and 4 described later) in the underground heat pump circuit 40.

  The first heat exchanger 41 and the underground heat source heat exchanger 45 are constituted by, for example, plate heat exchangers. In this plate heat exchanger, a plurality of heat transfer plates are stacked, and the circulating fluid L (or heat medium H1; see FIG. 3 and the like to be described later) serving as a heat medium and a refrigerant flow path for circulating the first refrigerant C1. The fluid flow paths to be circulated are alternately formed with each heat transfer plate as a boundary.

  The temperature of the first refrigerant C1 discharged from the first compressor 43 is detected by the first refrigerant discharge temperature sensor 42a. Similarly, of the refrigerant temperature sensors 42c and 42b provided in the first refrigerant pipe 42 from the first heat exchanger 45 to the underground heat source heat exchanger 45 through the first expansion valve 44, the first expansion is performed. By a first refrigerant temperature sensor 42b as refrigerant temperature detection means provided in the first refrigerant pipe 42 from the valve 44 to the underground heat source heat exchanger 45, the low pressure side (during heating operation) or the high pressure side (during cooling operation). The temperature of the first refrigerant C1 is detected. The detection results of the first refrigerant discharge temperature sensor 42 a and the first refrigerant temperature sensor 42 b are input to the underground heat control device 61.

  The air heat heat pump circuit 50 includes a variable capacity second compressor 53, a second heat exchanger 51 as a second load side heat exchanger, a second expansion valve 54, and a second heat source side heat exchanger. The air heat source heat exchanger 55 is annularly connected by a second refrigerant pipe 52. The second refrigerant pipe 52 is provided with a four-way valve 58 as a switching valve for switching the flow direction of the second refrigerant C2 (see FIGS. 3 and 4 described later) in the air heat heat pump circuit 50.

  As described above, the second heat exchanger 51 is configured by, for example, a plate heat exchanger, and each of the refrigerant flow path through which the second refrigerant C2 flows and the fluid flow path through which the circulating liquid L flows. It is formed alternately with the heat transfer plate as a boundary.

  The temperature of the second refrigerant C2 discharged from the second compressor 53 is detected by the second refrigerant discharge temperature sensor 52a. Similarly, the second refrigerant temperature sensor 52b provided in the second refrigerant pipe 52 from the second expansion valve 54 to the air heat source heat exchanger 55 causes a second low pressure side (during heating) or high pressure side (during cooling). The temperature of the refrigerant C2 is detected. Further, the temperature of the outside air is detected by an outside air temperature sensor 57 as outside air temperature detecting means. The detection results of the second refrigerant discharge temperature sensor 52 a and the outside air temperature sensor 57 are input to the air heat control device 62.

  In addition, as said 1st refrigerant | coolant C1 of the said geothermal heat pump circuit 40, and said 2nd refrigerant | coolant C2 of the said air heat heat pump circuit 50, arbitrary refrigerant | coolants, such as HFC refrigerant | coolants, such as R410A and R32, and a carbon dioxide refrigerant | coolant, for example Can be used.

  The underground heat circulation circuit 20 is configured to circulate through the underground heat circulation pump 22 having a variable rotation speed (number of rotations per unit time), the underground heat source heat exchanger 45, and the underground heat source heat exchanger 45. A ground heat exchanger 23 installed as a heat source for exchanging heat with one refrigerant C1 (in this example, in the ground) is connected in an annular shape by a ground heat pipe 21 serving as a heat medium pipe. An antifreeze liquid to which ethylene glycol, propylene glycol or the like is added is circulated in the underground heat pipe 21 as a heat medium H1 (see FIGS. 3 and 4 described later) by the underground heat circulation pump 22, and the heat An underground cistern 24 for storing the medium H1 and adjusting the pressure of the underground heat circulation circuit 20 is provided. The underground heat exchanger 23 is not limited to being provided in the ground, and may be provided in a water source such as a lake, a reservoir, a well, and the like, and heat may be collected therefrom.

  In the terminal circulation circuit 30, the first heat exchanger 41, the second heat exchanger 51, and a heat exchange terminal 36 as a load terminal such as a fan coil, a floor heating panel, a panel convector, etc. Are connected in an annular form in order from the upstream side. The load pipe 31 is provided with a circulating fluid circulating pump 32 that circulates the circulating fluid L in the terminal circulating circuit 30 and a heating systern 35 that stores the circulating fluid L and adjusts the pressure of the terminal circulating circuit 30. Yes. In this example, the circulating fluid circulation pump 32 is configured to rotate at a constant speed (a constant rotational speed). The heat exchange terminal 36 can be operated by a terminal remote controller 60b. Although one heat exchange terminal 36 is provided in FIG. 2, two or more heat exchange terminals 36 may be provided in parallel, and the number and specifications are not particularly limited.

  At this time, in the terminal circulation circuit 30, the first heat exchanger 41 and the second heat exchanger 51 are connected in series, and as described above, the circulating fluid that circulates in the terminal circulation circuit 30. The first heat exchanger 41 is disposed upstream of the second heat exchanger 51 with respect to the flow of L. That is, the heat pump device 1 uses the first heat exchanger 41 of the underground heat pump circuit 40 that heats or cools the circulating liquid L on the heat exchange terminal 36 side using an underground heat source, and an air heat source. The second heat exchanger 51 of the air heat heat pump circuit 50 that heats or cools the circulating liquid L on the heat exchange terminal 36 side is a composite heat source heat pump device connected in series to the terminal circulation circuit 30. Is.

  The load pipe 31 is provided with a return fluid temperature sensor 34 as a circulating fluid temperature detecting means for detecting the temperature of the circulating fluid L flowing into the first heat exchanger 41 from the heat exchange terminal 36. The detection result is input to the underground heat control device 61 and the air heat control device 62. In addition, the structure which acquires the detection result of the return liquid temperature sensor 34 via the said underground heat control apparatus 61 may be sufficient as the air heat control apparatus 62 not directly connected to the return liquid temperature sensor 34.

  Here, the heat pump device 1 can selectively function as a heating device that performs a heating operation by switching the four-way valves 46 and 58 or a cooling device that performs a cooling operation. Next, the cooling operation and the heating operation will be described with reference to FIGS. 3 and 4.

  FIG. 3 shows a state during the cooling operation. Note that various signal lines shown in FIG. 2 are omitted in order to prevent the illustration from being complicated. In the cooling operation shown in FIG. 3, the geothermal heat pump circuit 40 switches the four-way valve 46 as shown in the figure, so that the first refrigerant C1 discharged from the first compressor 43 is After the medium heat source heat exchanger 45, the first expansion valve 44, and the first heat exchanger 41 are circulated in this order, a flow path that returns to the first compressor 43 is formed. Thus, in the underground heat source exchanger 45 functioning as a condenser after the first refrigerant C1 in the gas state sucked at low temperature and low pressure is compressed by the first compressor 43 to become high temperature and high pressure gas. Then, heat exchange is performed with the heat medium H1 flowing through the underground heat circulation circuit 20, and the heat medium H1 is changed into a high-pressure liquid while releasing heat. Thus, the first refrigerant C1 that has become liquid is decompressed by the first expansion valve 44 and becomes a low-pressure liquid that easily evaporates. In the first heat exchanger 41 that functions as an evaporator, the terminal circulation circuit Heat is exchanged with the circulating fluid L flowing through 30 to evaporate and change into a gas to absorb heat and cool the circulating fluid L, and then return to the first compressor 43 again as a low-temperature and low-pressure gas.

  On the other hand, in the air heat heat pump circuit 50, when the four-way valve 58 is switched as shown, the second refrigerant C2 discharged from the second compressor 53 is supplied to the air heat source heat exchanger 55 and the second expansion valve. 54 and the 2nd heat exchanger 51 are distribute | circulated in order, Then, the flow path which returns to the 2nd compressor 53 is formed. Thereby, the second refrigerant C2 in the gas state sucked at a low temperature and a low pressure is compressed by the second compressor 53 to become a high temperature and a high pressure gas, and then the air heat source heat exchanger 55 functioning as a condenser. , The heat exchange with the air sent by the operation of the blower fan 56 is performed to change the liquid into a high-pressure liquid while releasing heat to the outside air. The second refrigerant C2 that has become liquid in this manner is reduced in pressure by the second expansion valve 54, becomes a low-pressure liquid, and easily evaporates. In the second heat exchanger 51 that functions as an evaporator, the terminal circulation circuit Heat is exchanged with the circulating liquid L flowing through 30 to evaporate and change into gas, thereby absorbing the heat and cooling the circulating liquid L, and then returning to the second compressor 53 again as a low-temperature and low-pressure gas.

  In the underground heat circulation circuit 20, the heat medium H <b> 1 is supplied to the underground heat source heat exchanger 45 by the underground heat circulation pump 22. In the underground heat source heat exchanger 45 that functions as a condenser, the first refrigerant C1 that flows through the refrigerant flow path of the underground heat source heat exchanger 45 and the fluid flow path of the underground heat source heat exchanger 45 are provided. After the circulating heat medium H1 faces and exchanges heat, the heat of the first refrigerant C1 at a high temperature is dissipated to the heat medium H1 side and the first refrigerant C1 is cooled, The heat of the medium H1 is radiated to the ground by the underground heat exchanger 23.

  In the terminal circulation circuit 30, the circulating liquid L that has flowed into the first heat exchanger 41 by the circulating liquid circulation pump 32 is heated in the first heat exchanger 41 that functions as an evaporator. In the second heat exchanger 51 functioning as an evaporator, the air heat source heat exchanger in the second heat exchanger 51 after being cooled by performing heat exchange with the first refrigerant C1 that has been heat-exchanged with the medium H1 and cooled as described above. At 55, heat is exchanged with the outside air, and heat is exchanged with the second refrigerant C2 cooled as described above to further cool. The circulating fluid L thus cooled is then supplied to the heat exchange terminal 36 to cool the air-conditioned space.

  In addition, in the above, although the state at the time of the air_conditionaing | cooling operation which operated both the underground heat pump unit 4 and the air heat pump unit 5 was demonstrated and demonstrated in FIG. 3, it is not restricted to this. That is, a cooling operation in which only the geothermal heat pump unit 4 is operated or a cooling operation in which only the air heat heat pump unit 5 is operated is possible.

  FIG. 4 shows a state during heating operation. Note that various signal lines shown in FIG. 2 are omitted in order to prevent the illustration from being complicated. In the heating operation shown in FIG. 4, in the geothermal heat pump circuit 40, the first refrigerant C <b> 1 discharged from the first compressor 43 is changed to the first by switching the four-way valve 46 as shown in the figure. After the first heat exchanger 41, the first expansion valve 44, and the underground heat source heat exchanger 45 are circulated in this order, a flow path that returns to the first compressor 43 is formed. Accordingly, the first heat exchanger 41 functioning as a condenser after the gas-state first refrigerant C1 sucked at low temperature and low pressure is compressed by the first compressor 43 to become high temperature and high pressure gas. Then, heat is exchanged with the circulating fluid L flowing through the terminal circulating circuit 30 to release heat to the circulating fluid L and change into a high-pressure liquid while heating. Thus, the first refrigerant C1 that has become liquid is decompressed by the first expansion valve 44 and becomes a low-pressure liquid that easily evaporates. In the underground heat source heat exchanger 45 that functions as an evaporator, Heat exchange is performed with the heat medium H1 flowing through the heat circulation circuit 20 to evaporate and change into a gas, thereby absorbing heat, and returning to the first compressor 43 again as a low-temperature and low-pressure gas.

  On the other hand, in the air heat heat pump circuit 50, the second refrigerant C2 discharged from the second compressor 53 is converted into the second heat exchanger 51 and the second expansion valve by switching the four-way valve 58 as shown in the figure. 54 and the air heat source heat exchanger 55 are circulated in this order, and then a flow path returning to the second compressor 53 is formed. As a result, the second refrigerant C2 in the gas state sucked at a low temperature and a low pressure is compressed by the second compressor 53 to become a high temperature and a high pressure gas, and then functions as a condenser. Then, heat exchange with the circulating fluid L flowing through the terminal circulating circuit 30 is performed to release heat to the circulating fluid L, which changes into a high-pressure liquid while being heated. The second refrigerant C2 that has become liquid in this manner is decompressed by the second expansion valve 54 and becomes a low-pressure liquid that easily evaporates. In the air heat source heat exchanger 55 that functions as an evaporator, the operation of the blower fan 56 is performed. Heat exchanges with the air sent by the air to evaporate and change to gas, thereby absorbing heat and returning to the second compressor 53 again as a low-temperature and low-pressure gas.

  Further, in the underground heat circulation circuit 20, the underground heat is collected from the underground by the underground heat exchanger 23, and the heat medium H <b> 1 having the heat is exchanged by the underground heat circulation pump 22 for the underground heat source heat exchange. Supplied to the vessel 45. In the underground heat source heat exchanger 45 that functions as an evaporator, the first refrigerant C1 that flows through the refrigerant flow path of the underground heat source heat exchanger 45 and the fluid flow path of the underground heat source heat exchanger 45 are provided. Heat exchange is performed with the circulating heat medium H1, and the underground heat collected by the underground heat exchanger 23 is pumped to the first refrigerant C1 side, and the first refrigerant C1 is heated as described above. .

  Further, in the terminal circulation circuit 30, the circulating liquid L that has flowed into the first heat exchanger 41 by the circulating liquid circulation pump 32 is supplied to the first heat exchanger 41 that functions as a condenser in the underground heat circulation circuit 20. In the second heat exchanger 51 functioning as a condenser, after heat exchange with the heat medium H1 and heat exchange with the first refrigerant C1 heated as described above, the air heat source heat exchange Heat is exchanged with the outside air in the vessel 55 and heat is exchanged with the second refrigerant C2 heated as described above, and further heated. The circulating liquid L thus heated is then supplied to the heat exchange terminal 36 to heat the air-conditioned space.

  In addition, in the above, although the state at the time of the heating operation which operated both the underground heat pump unit 4 and the air heat heat pump unit 5 was shown and demonstrated in FIG. 4, it is not restricted to this. That is, a heating operation in which only the geothermal heat pump unit 4 is operated or a heating operation in which only the air heat heat pump unit 5 is operated is possible.

  Next, the underground heat control device 61 and the air heat control device 62 will be described. Although not shown in detail, the underground heat control device 61 and the air heat control device 62 include a storage unit that stores various data and programs, and a control unit that performs calculation / control processing. First, functional configurations of the underground heat control device 61 and the air heat control device 62 during the cooling operation will be described with reference to FIG.

  As shown in FIG. 5, the underground heat control device 61 functionally includes a compressor control unit 61A, an expansion valve control unit 61B, and a pump control unit 61C. The underground heat control device 61 is communicably connected to the terminal control device 36a and the main remote controller 60a provided in the heat exchange terminal 36 (see FIG. 2).

  The compressor controller 61A determines the first compressor 43 in accordance with the temperature of the circulating fluid L (cold water) detected by the return fluid temperature sensor 34 (hereinafter referred to as “return cold water temperature” as appropriate, see FIG. 3). Control the number of revolutions. Particularly in this example, the compressor control unit 61A causes the return chilled water temperature of the circulating fluid L detected by the return fluid temperature sensor 34 to be a desired target return temperature corresponding to the operation of the main remote controller 60a, for example. In addition, the rotational speed of the first compressor 43 is controlled.

  The expansion valve control unit 61B controls the valve opening degree of the first expansion valve 44 according to the refrigerant discharge temperature of the first refrigerant C1 detected by the first refrigerant discharge temperature sensor 42a. In particular, in this example, the expansion valve control unit 61B determines that the refrigerant discharge temperature of the first refrigerant C1 detected by the first refrigerant discharge temperature sensor 42a becomes a control target temperature corresponding to, for example, the operation of the main remote controller 60a. Thus, the valve opening degree of the first expansion valve 44 is controlled.

  The pump control unit 61C detects the temperature of the first refrigerant C1 detected by the first refrigerant temperature sensor 42b (at this time, the underground heat source heat exchanger 45 functions as a condenser. The rotation speed of the underground heat circulation pump 22 is controlled according to the temperature) (see also FIG. 2). Particularly in this example, the pump control unit 61C is configured so that the condenser outlet refrigerant temperature of the first refrigerant C1 detected by the first refrigerant temperature sensor 42b becomes a substantially constant value. The number of revolutions is controlled.

  The air heat controller 62 functionally includes a compressor controller 62A, an expansion valve controller 62B, and a fan controller 62C. The air heat control device 62 is communicably connected to the underground heat control device 61 (see FIG. 2).

  The compressor control unit 62A controls the rotation speed of the second compressor 53 according to the return cold water temperature (see FIG. 3) detected by the return liquid temperature sensor 34. Particularly in this example, the compressor control unit 62A causes the return chilled water temperature detected by the return liquid temperature sensor 34 to be a desired target temperature (target return temperature) corresponding to the operation of the main remote controller 60a, for example. The rotational speed of the second compressor 53 is controlled. The compressor control unit 62A of the air heat control device 62 and the compressor control unit 61A of the underground air heat control device 61 cooperate with each other as necessary, and are the target first compressor 43. Alternatively, the second compressor 53 is controlled.

  The expansion valve control unit 62B controls the valve opening degree of the second expansion valve 54 in accordance with the refrigerant discharge temperature of the second refrigerant C2 detected by the second refrigerant discharge temperature sensor 52a. In particular, in this example, the expansion valve control unit 62B determines that the refrigerant discharge temperature of the second refrigerant C2 detected by the second refrigerant discharge temperature sensor 52a is a control target temperature corresponding to, for example, the operation of the main remote controller 60a. Thus, the valve opening degree of the second expansion valve 54 is controlled. The expansion valve control unit 62B of the air heat control device 62 and the expansion valve control unit 61B of the underground air heat control device 61 cooperate with each other as necessary, and are the target first expansion valve 44. Alternatively, the second expansion valve 54 is controlled.

  The fan control unit 62C controls the rotational speed of the blower fan 56 according to the temperature of the outside air detected by the outside air temperature sensor 57 (see also FIG. 2).

  In the above description with reference to FIG. 5, the description is based on input / output of information during the cooling operation. However, during the heating operation, as shown in FIG. 6, the geothermal control device 61 and the air heat control device 62 The content of the input / output information is different with the configuration unchanged. That is, the temperature of the circulating fluid L detected by the return fluid temperature sensor 34 is a so-called warm water temperature (hereinafter referred to as “return warm water temperature”, refer to FIG. 4 as appropriate). 62A is input. Further, the temperature of the refrigerant C1 detected by the first refrigerant temperature sensor 42b, that is, the evaporator inlet refrigerant temperature (at this time, the underground heat source heat exchanger 45 functions as an evaporator) is input to the pump control unit 61C. The

  In the heat pump device 1 having the above basic configuration and operation, the main part of the present embodiment is a switching control unit 61p (details will be described later) newly provided in the compressor control unit 61A on the ground heat control device 61 side. The contents of the control for the first compressor 43 (reduction control of the rotational speed of the first compressor 43, details will be described later). Hereinafter, the details will be described in order.

  First, as described above, the heat pump device 1 according to the present embodiment uses the two heat sources of the ground heat source and the air heat source in combination, but how to efficiently combine and use these different heat sources (in other words, paraphrase) For example, it is important to determine how to switch and combine the ground heat source and the air heat source. However, the outdoor air that is a fluid (gas phase) and the soil in the ground that is a solid (solid phase) are greatly different in characteristics and handling as a heat source. For example, outdoor air has a large temperature change in summer and winter, while the temperature in the ground is small throughout the year. Although all heat sources have a large heat capacity, outdoor air has a high heat transfer rate and can be circulated by blowing with a fan, while underground soil has a low heat transfer rate and is fixed. Cannot be circulated. For this reason, outdoor air is easy to detect the temperature in the whole outside air, but the temperature in the whole earth is difficult to detect because the temperature distribution in the soil in the ground tends to be locally localized.

  From the above, first, in the present embodiment, the switching and combination of the air heat source and the underground heat source are determined based on the outside air temperature. That is, based on the outside air temperature detected by the outside air temperature sensor 57 (see FIGS. 5 and 6), the switching control units 61p and 62p as the control means provided in the compressor control units 61 and 62 are linked with each other, In the terminal circulation circuit 30 capable of performing both heat exchange in the first heat exchanger 41 and heat exchange in the second heat exchanger 51, which heat exchange is the main and which heat exchange is the auxiliary Switch.

  For example, at the time of cooling operation, as shown in FIG. 7A, if the outside air temperature is not so high (in this example, less than 30 ° C.) in spring or autumn, a large heat release to the outside air can be expected. The second compressor 53 using the air heat source is preferentially driven as a main power source, and the first compressor 43 using the underground heat source is driven as an auxiliary power source.

  On the other hand, when the outside air temperature is relatively high in the summer season or the like (in this example, 30 ° C. or higher), the first compressor 43 that uses the underground heat source is mainly used because heat radiation to the outside air cannot be expected so much. The second compressor 53, which is preferentially driven as a power source and uses an air heat source, is driven as an auxiliary power source.

  That is, in this embodiment, the reference temperature (first reference temperature) for switching between the main power source and the auxiliary power source during the cooling operation is 30 ° C. (see illustration).

  Further, for example, during heating operation, as shown in FIG. 7B, when the outside air temperature is relatively low (in this example, less than 5 ° C.) in the winter season, heat exchange from the outside air is performed by absorbing heat from the outside air. The first compressor 43 is preferentially driven as a main power source and the second compressor 53 is driven as an auxiliary power source because there is a problem that the device 55 is frosted.

  Conversely, when the outside air temperature is not so low (in this example, 5 ° C. or higher) in autumn or spring, the air heat source heat exchanger 55 is not easily frosted even if it absorbs heat from the outside air. The compressor 53 is preferentially driven as a main power source, and the first compressor 43 is driven as an auxiliary power source.

  That is, in the present embodiment, the reference temperature (second reference temperature) for switching between the main power source and the auxiliary power source during the heating operation is 5 ° C. (see illustration).

  Here, an example of the effect of the combined operation of the main power source and the auxiliary power source will be described with reference to FIG. 8 taking the case of the cooling operation as an example. For example, in a cooling operation when the outside air temperature is relatively high (30 ° C. in this example), a behavior when the air heat heat pump circuit 50 of the air heat heat pump unit 5 alone is operated alone is shown in FIG. .

  As shown in FIG. 8A, in this case, the temperature of the circulating fluid L flowing into the second heat exchanger 51 (the return value) under a predetermined operating condition (the flow rate of the circulating fluid L 10 [L / min]). The cold water temperature) is 17 ° C., and only the air heat heat pump circuit 50 of the air heat heat pump unit 5 is operated at an output of 7 [kW], so that the circulating liquid L flowing out of the second heat exchanger 51 is reduced. The temperature is 7 ° C. At this time, the COP (coefficient of performance) of the air heat pump unit 5 is 3.0.

The COP is
COP = cooling capacity [kW] of the heat pump unit 4 (or 5) / (power consumption [kW] of the compressor 43 (or 53) + power consumption [kW] of the controller 61 (or 62))
It is calculated by.

The overall system COP at this time is 3.0, which is the same as the COP (since it is an independent operation of the air heat heat pump unit 5 as described above). The system COP (SCOP) at this time is an extension of the COP to the entire unit.
SCOP = cooling capacity [kW] of heat pump units 4 and 5 / total power consumption [kW] of heat pump units 4 and 5
It is represented by In particular,
SCOP≈cooling capacity of the heat pump units 4 and 5 [kW] / (power consumption of the compressors 43 and 53 [kW] + power consumption of the control devices 61 and 62 [kW] + power consumption of the circulating fluid circulation pump 32 [kW] + Power consumption of underground heat circulation pump 22 [kW])
It is represented by

  On the other hand, in response to the behavior of FIG. 8A, when the geothermal heat pump circuit 40 of the geothermal heat pump unit 4 and the air heat heat pump circuit 50 of the air heat heat pump unit 5 are operated in combination. The behavior is shown in FIG.

  As shown in FIG. 8 (b), in this case, the geothermal heat pump is operated under substantially the same operating conditions as above (flow rate of circulating fluid L 10 [L / min], underground return chilled water temperature: 25 ° C.). When the temperature of the circulating fluid L flowing into the first heat exchanger 41 of the unit 4 (the return cold water temperature) is 17 ° C., and the underground heat pump circuit 40 is operated at an output of 3 [kW], The temperature of the circulating liquid L flowing out of the first heat exchanger 41 becomes 13 ° C. Then, the circulating liquid L at 13 ° C. flows into the second heat exchanger 51 of the air heat heat pump unit 5, and the air heat heat pump circuit 50 is operated at an output of 4 [kW] at that time. The temperature of the circulating liquid L flowing out from the second heat exchanger 51 is 7 ° C.

  That is, the behavior shown in FIG. 8A and the behavior shown in FIG. 8B are the same in the cold water temperature (17 ° C.) on the inlet side and the cold water temperature (7 ° C.) on the outlet side. The output of the entire heat pump circuit to be performed is the same at 7 [kW]. In the combined operation shown in FIG. 8 (b), the COP of the air heat heat pump unit 5 is 3.0 as described above, while the COP of the underground heat pump unit 4 is 5.2. As a result, the overall system COP can be improved to 3.66.

  However, in the combined operation as shown in FIG. 8B, the ground heat source is used depending on the outside air temperature and the load condition only by the simple switching between the main and the auxiliary due to the high and low outside air temperature as described above. The geothermal heat pump circuit 40 may exceed an assumed operation amount, and there is a risk that the temperature recovery in the ground may be hindered or the efficiency of the geothermal heat pump circuit 40 may be reduced.

  Specifically, in the geothermal heat pump circuit 40, since the temperature increases and decreases locally only in the vicinity of the underground heat exchanger 23 and is easily fixed, the heat absorption performance of the underground heat exchanger 23 The heat dissipation performance is degraded, and the large heat capacity of the entire underground heat source is not used up effectively, and the efficiency tends to decrease. Moreover, since the temperature recovery is slow in the underground heat source, the efficiency tends to decrease even at the time of restart. In particular, in the heat pump device 1 (so-called hybrid type) that uses an air heat source and a ground heat source in a composite manner as in the present embodiment, the use of the air heat source is anticipated and the case where the ground heat source is used alone (that is, For example, the underground heat exchanger 23 may be embedded in half the length of the intermediate heat pump circuit 40), and the above-described efficiency reduction due to excessive heat absorption / dissipation tends to occur. This will be described with reference to FIG.

  FIG. 9 shows an example in which the outside air temperature is higher than 30 ° C., the first compressor 43 that uses a ground heat source is driven as a main power source, and the second compressor 53 that uses an air heat source assists. An example of cooling operation when driven as a power source is shown. First, the case where only the main / auxiliary simple switching based on the high / low outside air temperature is performed is indicated by a broken line as a comparative example.

  As indicated by the broken line in the figure, the output from the geothermal heat pump unit 4 (indicated as “geothermal output” in the figure) and the output from the air heat heat pump unit 5 (indicated as “air heat output” in the figure) are respectively shown. Even if the SCOP is maintained at a constant level, the heat dissipation efficiency gradually decreases as the vicinity of the underground heat exchanger 23 is locally heated as described above. The outlet refrigerant temperature gradually increases. When the condenser outlet refrigerant temperature reaches 30 ° C. (see time to), after that, the output from the geothermal heat pump unit 4 and the output from the air heat heat pump unit 5 are kept constant to operate. However, the temperature of the first refrigerant C1 as a whole rises, the efficiency of the underground heat pump unit 4 side decreases, and as a result, the SCOP decreases.

  The same problem as described above also occurs during heating operation. As an example, the outside air temperature is lower than 5 ° C., the first compressor 43 using a ground heat source is driven as a main power source, and the second compressor 53 using an air heat source is used as an auxiliary power source. An example of heating operation when driven is shown in FIG. Similarly to the above, the case where only the main / auxiliary simple switching by the high / low outside air temperature is performed is indicated by a broken line as a comparative example.

  As indicated by the broken line in the figure, the output from the geothermal heat pump unit 4 (indicated as “geothermal output” in the figure) and the output from the air heat heat pump unit 5 (indicated as “air heat output” in the figure) are respectively shown. Even if the SCOP is maintained at a constant level, the endothermic efficiency gradually decreases as the vicinity of the underground heat exchanger 23 is locally cooled as described above. The inlet refrigerant temperature gradually decreases. When the evaporator inlet refrigerant temperature decreases to −10 ° C. (see time to), thereafter, the output from the geothermal heat pump unit 4 and the output from the air heat heat pump unit 5 are maintained constant. However, the temperature of the first refrigerant C1 as a whole decreases, the efficiency of the underground heat pump unit 4 decreases, and as a result, the SCOP decreases.

  Therefore, in the present embodiment, the first refrigerant temperature sensor 42b causes the condenser outlet refrigerant temperature flowing out from the underground heat source heat exchanger 45 in the underground heat pump circuit 40 (during cooling operation), or the An evaporator inlet refrigerant temperature (during heating operation) flowing into the intermediate heat source heat exchanger is detected. Then, the switching control unit 61p provided in the geothermal heat control device 61 determines the first temperature according to the detected condenser outlet refrigerant temperature or the evaporator inlet refrigerant temperature and a predetermined threshold value. 1 Rotation speed of the compressor 43 is reduced.

  That is, for example, during cooling operation, as indicated by a solid line in FIG. 9, the detected condenser outlet refrigerant temperature is referred to as a predetermined threshold value (hereinafter referred to as “first threshold value” as appropriate. In this example, 30 ° C.). ) (See time to), the switching control unit 61p reduces the rotational speed of the first compressor 43 and lowers the output of the underground heat pump unit 4. Correspondingly, in the present embodiment, the output of the air heat heat pump unit 5 is increased so as to supplement the reduced output of the underground heat pump unit 4 with respect to the cooling load. As a result, it is possible to suppress a decrease in heat dissipation efficiency due to excessive operation of the underground heat pump unit 4 as described above and local heating of the vicinity of the underground heat exchanger 23 locally ( As a result, unlike the comparative example, the condenser outlet refrigerant temperature gradually decreases from 30 ° C.), and the SCOP of the entire system can be prevented from decreasing and maintained constant. In addition, after the operation of the entire heat pump device 1 is stopped as shown in the drawing, the underground temperature can be recovered to a low temperature faster than the comparative example, so that there is an effect that the SCOP at the start of the next operation can be improved.

  Similarly, during the heating operation, as shown by a solid line in FIG. 10, the detected evaporator inlet refrigerant temperature is referred to as a predetermined threshold (hereinafter referred to as “second threshold” as appropriate. In this example, −10) When the temperature is lower than (° C.) (see time to), the switching control unit 61p reduces the rotation speed of the first compressor 43 and lowers the output of the underground heat pump unit 4. Correspondingly, in the present embodiment, the output of the air heat heat pump unit 5 is increased so as to supplement the reduced output of the underground heat pump unit 4 with respect to the heating load. As a result, as described above, it is possible to suppress a decrease in heat absorption efficiency due to excessive operation of the underground heat pump unit 4 and excessively cooling the vicinity of the underground heat exchanger 23 ( As a result, unlike the comparative example, the evaporator inlet refrigerant temperature gradually increases from −10 ° C.), and the SCOP of the entire system can be prevented from being lowered and kept constant. In addition, after the operation of the entire heat pump device 1 is stopped as shown in the drawing, the underground temperature can be recovered to a higher temperature faster than the comparative example, so that there is an effect that the SCOP at the start of the next operation can be improved.

The COP during the heating operation is
COP = heating capacity [kW] of the heat pump unit 4 (or 5) / (power consumption [kW] of the compressor 43 (or 53) + power consumption [kW] of the control device 61 (or 62))
And the overall system COP is
SCOP = heating capacity of heat pump units 4 and 5 [kW] / total power consumption of heat pump units 4 and 5 [kW]
In particular,
SCOP≈heating capacity of heat pump units 4 and 5 [kW] / (power consumption of compressors 43 and 53 [kW] + power consumption of control devices 61 and 62 [kW] + power consumption of circulating fluid circulation pump 32 [kW] + Power consumption of underground heat circulation pump 22 [kW])
It is represented by

  The effects of the present embodiment when compared with the comparative example as described above will be described in more detail with reference to FIG. 11 taking the cooling operation as an example. In FIG. 11A, FIG. 11A shows a time course of COP (denoted as “air COP” in the figure, the same applies hereinafter) in the air heat heat pump unit 5 using an air heat source, and FIG. The time course of COP in the geothermal heat pump unit 4 using a geothermal heat source (denoted as “Ground COP” in the figure, the same applies hereinafter) is shown. FIG. 11C shows the time course of the cooling output value [kw] of the air heat heat pump unit 5 (indicated as “air heat output” in the figure, the same applies hereinafter), and FIG. Indicates the time course of the cooling output value [kw] of the geothermal heat pump unit 4 (denoted as “Ground heat output” in the figure, the same applies hereinafter). FIG. 11 (e) shows the time course of the underground temperature [° C.] around the underground heat exchanger 23, and FIG. 11 (f) shows the condenser in the underground heat pump circuit 40. A time course of the outlet refrigerant temperature [° C.] (detected by the first refrigerant temperature sensor 42b in the present embodiment; the same applies hereinafter) is shown.

  First, in the comparative example indicated by the broken line, for example, when the cooling operation of the heat pump apparatus 1 is started, the output of the air heat heat pump unit 5 and the output of the underground heat pump unit 4 increase almost simultaneously, and are constant at each target output. (See times t1 to t6 in FIGS. 11C and 11D). At this time, the output of the main underground heat pump unit 4 is higher than that of the auxiliary air heat heat pump unit 5. Along with this, the COP of the air heat heat pump unit 5 and the COP of the underground heat pump unit 4 also increase and are kept constant according to their respective target outputs (time t1 in FIGS. 11A and 11B). To t6 etc.). During this start-up and steady operation, since the surrounding heat of the underground heat exchanger 23 proceeds, the underground temperature continuously increases (see times t1 to t6 in FIG. 11 (e), etc.) As a result, the heat radiation effect in the underground heat exchanger 23 gradually decreases, so that the condenser outlet refrigerant temperature also continuously increases (see times t1 to t6 in FIG. 11 (f), etc.).

  In the comparative example, as described above, the output of the air heat heat pump unit 5 and the output of the underground heat pump unit 4 are kept constant even when the condenser outlet refrigerant temperature exceeds 30 ° C. ( 11 (c) and 11 (d) (see time t6 to t11), the underground temperature and the condenser outlet refrigerant temperature continue to rise (see time t6 to t11 in FIGS. 11 (e) and 11 (f)). . At this time, as described above, since the heat radiation effect in the vicinity of the underground heat exchanger 23 is lowered, the COP of the underground heat pump unit 4 gradually decreases (see times t6 to t11 in FIG. 11B). As a result, as described above, after the condenser outlet refrigerant temperature exceeds 30 ° C., the coefficient of performance SCOP of the entire heat pump device 1 decreases (see time to in FIG. 9).

  After that, when the cooling operation of the heat pump device 1 is stopped (see time t11), the underground temperature gradually decreases thereafter (see times t11 to t15 in FIG. 11 (e)), but recovers to the original temperature. Takes a lot of time. For this reason, when the heat pump apparatus 1 is restarted before the ground temperature has not yet decreased within a relatively short period of time (see time t15), the condenser outlet refrigerant temperature once lowered to the original temperature. Even if it is the case where the output of the geothermal heat pump unit 4 is the same as the previous time, the COP is further lowered because it rises earlier than the previous operation start time (see time t15 to t20 in FIG. 11 (f)). (See time t16 to t20 in FIG. 11B).

  On the other hand, in the present embodiment indicated by the solid line, in order to prevent the COP of the geothermal heat pump unit 4 from being lowered due to the overheating of the underground temperature as described above, the condenser outlet refrigerant temperature is the first temperature. When the threshold value is higher than 30 ° C., the switching control unit 61p of the underground heat control device 61 reduces the rotational speed of the first compressor 43. As a result, the output of the geothermal heat pump unit 4 is constantly saved so that the condenser outlet refrigerant temperature maintains the first threshold value of 30 ° C. (see times t7 to t11 in FIG. 11D). ). Thereby, the temperature of the heat medium H1 in the underground heat circulation circuit 20 is lowered to less than 30 ° C. (see time t7 to t9 in FIG. 11 (e)), and is kept lowered to a temperature slightly lower than 30 ° C. ( (See time t9 to t11 in FIG. 11E). As a result of the output of the geothermal heat pump unit 4 being saved in this way, the heat dissipation effect in the vicinity of the underground heat exchanger 23 is favorably maintained. As a result, the COP of the geothermal heat pump unit 4 is improved. It is maintained at a high value (see time t6 to t11 in FIG. 11B).

  At this time, in this embodiment, the switching control unit 62p of the air heat control device 62 increases the rotation speed of the second compressor 53 so as to supplement the reduction in the output of the underground heat pump unit 4. Then, the output of the air heat heat pump unit 5 is increased (see time t6 to t11 in FIG. 11C). As a result, although the COP of the air heat heat pump unit 5 decreases (see time t6 to t11 in FIG. 11A), the decrease is offset by the increase in COP of the underground heat pump unit 4. Therefore, as a result, as shown in FIG. 9, even after the condenser outlet refrigerant temperature exceeds 30 ° C., the coefficient of performance SCOP of the entire heat pump device 1 can be maintained high without decreasing.

  When the cooling operation of the heat pump device 1 is stopped as described above (see time t11), unlike the comparative example, the underground temperature is sufficiently low at that time (time t11 in FIG. 11 (e)). reference). Therefore, even when the heat pump apparatus 1 is restarted in a relatively short period of time, the condenser outlet refrigerant temperature once lowered to the original temperature will rise to the same level as at the start of the previous operation (FIG. 11 (f ) (See time t15 to t20)), the same COP of the geothermal heat pump unit 4 as the previous time can be maintained (see time t16 to t20 in FIG. 11B).

  In addition, although the above demonstrated the case at the time of air_conditionaing | cooling operation as an example, the same subject arises also at the time of heating operation as mentioned above. This will be described with reference to FIGS. 12A to 12F corresponding to FIGS. 11A to 11F, respectively. In FIG. 12, FIG. 12 (a) shows the time course of COP in the air heat heat pump circuit 50 using the same air heat source as in FIG. 11 (a), and FIG. ) Shows the time course of COP in the underground heat pump circuit 40 using the same underground heat source. FIG. 12 (c) shows the time course of the heating output value [kw] (expressed as “air heat output” in the figure, the same applies hereinafter) of the air heat heat pump circuit 50 similar to FIG. 11 (c). 12 (d) shows the heating output value [kw] of the geothermal heat pump unit 450 similar to FIG. 11 (d) (denoted as “geothermal heat output” in the figure, the same applies hereinafter). It shows the transition. Moreover, FIG.12 (e) has shown the time-dependent transition of underground temperature [degreeC] around the underground heat exchanger 23 similar to the said FIG.11 (e), FIG.12 (f) is the said figure. 11 (f) shows the time course of the evaporator inlet refrigerant temperature [° C.] (detected by the first refrigerant temperature sensor 42b in the present embodiment; the same applies hereinafter) of the same geothermal heat pump circuit 40.

  First, in the comparative example indicated by a broken line, for example, when the heating operation of the heat pump device 1 is started, the output of the air heat heat pump unit 5 and the output of the underground heat pump unit 4 increase almost simultaneously as in the cooling operation. Each target output is kept constant (see times t1 to t6 in FIGS. 12C and 12D, etc.), and the main underground output becomes higher than the auxiliary air heat output. Along with this, the COP of the air heat heat pump unit 5 and the COP of the underground heat pump unit 4 also increase and are kept constant corresponding to each target output (time t1 in FIGS. 12 (a) and 12 (b)). To t6 etc.). During the start-up and the steady operation, since the cooling around the underground heat exchanger 23 proceeds, the underground temperature continuously decreases (see time t1 to t6 in FIG. 12 (e), etc.) As a result, the endothermic effect in the underground heat exchanger 23 gradually decreases, so that the evaporator inlet refrigerant temperature also continuously decreases (see times t1 to t6 in FIG. 12 (f), etc.).

  In the comparative example, as described above, the output of the air heat heat pump unit 5 and the output of the underground heat pump unit 4 are kept constant even when the evaporator inlet refrigerant temperature falls below −10 ° C. (Refer to the times t6 to t11 in FIGS. 12 (c) and 12 (d)), the underground temperature and the evaporator inlet refrigerant temperature continue to decrease (see the times t6 to t11 in FIGS. 12 (e) and 12 (f)). ). At this time, as described above, the endothermic effect in the vicinity of the underground heat exchanger 23 is reduced, so that the COP of the underground heat pump unit 4 gradually decreases (see times t6 to t11 in FIG. 12B). As a result, as described above, after the evaporator inlet refrigerant temperature falls below −10 ° C., the coefficient of performance SCOP of the entire heat pump device 1 decreases (see time to in FIG. 10).

  After that, when the heating operation of the heat pump device 1 is stopped (see time t11), the underground temperature gradually increases thereafter (see times t11 to t15 in FIG. 12E), but is restored to the original temperature. Takes a lot of time. For this reason, when the heat pump apparatus 1 is restarted before the underground temperature has not yet risen within a relatively short period (see time t15), the evaporator inlet refrigerant temperature once raised to the original temperature is It will decrease earlier than the previous start of operation (see time t15 to t20 in FIG. 12 (f)), and even when the output of the geothermal heat pump unit 4 is the same as the previous time, COP further decreases. (See times t16 to t20 in FIG. 12B).

  On the other hand, in the present embodiment indicated by the solid line, in order to prevent the COP of the geothermal heat pump unit 4 from being lowered due to the above-described subcooling of the underground temperature, the evaporator inlet refrigerant temperature is set to a predetermined value. When the temperature becomes lower than a threshold value (hereinafter referred to as “second threshold value”, in this example, −10 ° C.), the switching control unit 61p of the underground heat control device 61 rotates the first compressor 43. Reduce the number. As a result, the output of the geothermal heat pump unit 4 is constantly saved so that the evaporator inlet refrigerant temperature maintains the second threshold value of −10 ° C. (time t7 to t11 in FIG. 12D). reference). Thereby, the heat medium H1 in the underground heat circulation circuit 20 becomes higher than 0 degreeC (refer time t7-t9 of FIG.12 (e)), and it raises and is maintained to the temperature a little higher than 0 degreeC (FIG.12 ( e) Time t9 to t11). As a result of the output of the geothermal heat pump unit 4 being saved in this way, the endothermic effect in the vicinity of the underground heat exchanger 23 is favorably maintained. As a result, the COP of the geothermal heat pump unit 4 is improved. It is maintained at a high value (see time t6 to t11 in FIG. 12B).

  At this time, in the present embodiment, the switching control unit 62p of the air heat control device 62 is used for the second compressor so as to supplement the reduction in the output of the underground heat pump unit 4 as in the cooling operation. The rotational speed of 53 is increased, and the output of the air heat heat pump unit 5 is increased (see time t6 to t11 in FIG. 12C). For this reason, although the COP of the air heat pump unit 5 decreases (see time t6 to t11 in FIG. 12A), the decrease of the COP of the underground heat pump unit 4 cancels out the decrease. Therefore, as a result, as shown in FIG. 10, even after the evaporator inlet refrigerant temperature falls below −10 ° C., the coefficient of performance SCOP of the heat pump device 1 as a whole can be maintained high without decreasing.

  And when the heating operation of the heat pump apparatus 1 is stopped as described above (see time t11), unlike the comparative example, the underground temperature is sufficiently high at that time (time t11 in FIG. 12 (e)). reference). Therefore, even when the heat pump device 1 is restarted in a relatively short period of time, the evaporator inlet refrigerant temperature once raised to the original temperature is reduced to the same level as at the start of the previous operation (FIG. 12 (f ) (See times t15 to t20)), the same COP of the geothermal heat pump unit 4 as the previous time can be maintained (see times t16 to t20 in FIG. 12B).

  Next, in order to realize the method described above, a control procedure executed in cooperation by the two switching control units 61p and 62p will be described with reference to the flowcharts of FIGS.

  First, the control procedure during the cooling operation will be described with reference to FIG. In FIG. 13, the outside air temperature is higher than 30 ° C., the first compressor 43 using the underground heat source is already driven as a main power source, and the second compressor 53 using the air heat source is The case where it is driven as an auxiliary power source will be described as an example.

  In FIG. 13, first, in step S10, the switching control units 61p and 62p determine whether or not the heat pump device 1 is in an operation start state. Specifically, the operation start state is, for example, when the operation is started from the stop state by an appropriate operation start operation of the heat pump device 1 by the operator, or after restarting after the operation stop described above. This is when the operation of the heat pump device 1 is started again (details will be described later). Until the operation start state is reached, the determination in step S10 is not satisfied (S10: No), and the loop waits. When the operation start state is reached, the determination in step S10 is satisfied (S10: Yes), and the process proceeds to step S15.

  In step S15, the switching control units 61p and 62p determine whether or not the heat pump device 1 is in an operation end state. That is, when the cooling operation is performed under the control of the compressor rotation speed as described later and the cooling load is reduced, the return liquid temperature sensor 34 of the terminal circulation circuit 30 detects the cooling load without operating the heat pump device 1. In some cases, the return cold water temperature of the circulating fluid L reaches the target return temperature or lower. In this case, the heat pump device 1 is stopped by a known control by the underground heat control device 61 and the air heat control device 62, and enters a standby state (that is, the operation of the heat pump device 1 is once ended). In step S15, the switching controllers 61p and 62p determine whether or not the heat pump apparatus 1 has entered this standby state. If it is in the operation end state (that is, the standby state), the determination in step S15 is satisfied (S15: YES), and this flow is ended. On the other hand, the determination in step S15 is not satisfied while the operation is not finished (that is, in the standby state) (S15: NO), and the process proceeds to step S20.

  In step S20, the switching controllers 61p and 62p determine whether or not the condenser outlet refrigerant temperature detected from the first refrigerant temperature sensor 42b at this time exceeds a first threshold value (30 ° C. in this example). Determine whether. If the condenser outlet refrigerant temperature is 30 ° C. or lower, the determination is not satisfied (S20: NO), and the process returns to step S15 and the same procedure is repeated. On the other hand, when the condenser outlet refrigerant temperature exceeds 30 ° C., the determination is satisfied (S20: YES), and the routine goes to Step S25.

  In step S25, the switching controllers 61p and 62p reduce the rotation speed of the first compressor 43 of the geothermal heat pump circuit 40 and reduce the output of the geothermal heat pump unit 4. Thereafter, the process proceeds to step S30.

  In step S30, the switching controllers 61p and 62p indicate that the return chilled water temperature detected from the return liquid temperature sensor 34 at this time corresponds to the control target set temperature (the first target temperature. The same as the target temperature already described above). However, it may be another temperature, for example, it is determined whether or not the temperature exceeds an appropriate value according to the cooling load. If the return chilled water temperature exceeds the target set temperature, the determination is satisfied (S30: YES), and the routine goes to Step S35.

  In step S35, the switching controllers 61p and 62p increase the rotation speed of the second compressor 53 of the air heat heat pump circuit 50 and increase the output of the air heat heat pump unit 5. Then, it returns to step S15 and repeats the same procedure.

  On the other hand, in the determination of step S30, when the return chilled water temperature is equal to or lower than the target set temperature, the determination is not satisfied (S30: NO), and the process proceeds to step S40.

  In step S40, the switching control units 61p and 62p reduce the rotation speed of the second compressor 53 of the air heat heat pump circuit 50 and reduce the output of the air heat heat pump unit 5. Then, it returns to step S15 and repeats the same procedure. However, in the case where the return chilled water temperature is equal to the target set temperature in the determination in step S30, the determination in step S30 is not satisfied, but it is not always necessary to reduce the rotational speed of the second compressor 53 as described above. Alternatively, the rotational speed may be maintained as it is.

  As described above, in the present embodiment, during the cooling operation, the rotation speed of the first compressor 43 (in other words, in order to maintain the condenser outlet refrigerant temperature at about 30 ° C. by the processing in steps S20 and S25). The output of the geothermal heat pump unit 4 is controlled, and the rotation speed of the second compressor 53 (in other words, the output of the geothermal heat pump unit 4 is supplemented by the processes in steps S30, S35, and S40). The output of the air heat heat pump unit 5 is controlled.

  Next, the control procedure at the time of heating operation is demonstrated using FIG. In FIG. 14, the outside air temperature is lower than 5 ° C., the first compressor 43 using the underground heat source is already driven as a main power source, and the second compressor 53 using the air heat source is The case where it is driven as an auxiliary power source will be described as an example.

  In FIG. 14, first, in step S110, the switching controllers 61p and 62p determine whether or not the heat pump device 1 has entered the same operation start state as described above. Until the operation start state is reached, the determination in step S110 is not satisfied (S110: No), and the loop waits. When the operation start state is established, the determination in step S110 is satisfied (S110: Yes), and the process proceeds to step S115.

  In step S115, the switching control units 61p and 62p determine whether or not the heat pump device 1 is in an operation end state. In this case, when the heating operation is performed under the control of the compressor rotation speed as described later and the heating load becomes small, the return liquid temperature sensor of the terminal circulation circuit 30 does not operate the heat pump device 1. In some cases, the return hot water temperature of the circulating fluid L detected at 34 reaches or exceeds the target return temperature. In this case, the heat pump device 1 is stopped by known control by the underground heat control device 61 and the air heat control device 62, and enters a standby state similar to that during the cooling operation (that is, once the operation of the heat pump device 1 is performed). Finished). In step S115, the switching controllers 61p and 62p determine whether or not the heat pump apparatus 1 has entered this standby state. When it is in the operation end state (that is, the standby state), the determination in step S115 is satisfied (S115: YES), and this flow is ended. On the other hand, the determination in step S115 is not satisfied while the operation is not finished (that is, in the standby state) (S115: NO), and the process proceeds to step S120.

  In step S120, the switching controllers 61p and 62p indicate that the evaporator inlet refrigerant temperature detected from the first refrigerant temperature sensor 42b at this time is below the second threshold value (−10 ° C. in this example). It is determined whether or not. When the evaporator inlet refrigerant temperature is −10 ° C. or higher, the determination is not satisfied (S120: NO), and the process returns to step S115 and the same procedure is repeated. On the other hand, if the evaporator inlet refrigerant temperature is lower than −10 ° C., the determination is satisfied (S120: YES), and the routine goes to Step S125.

  In step S125, as in step S25, the switching controllers 61p and 62p reduce the rotation speed of the first compressor 43 of the geothermal heat pump circuit 40 and reduce the output of the geothermal heat pump unit 4. . Thereafter, the process proceeds to step S130.

  In step S130, as in step S30, the switching controllers 61p and 62p indicate that the return hot water temperature detected from the return liquid temperature sensor 34 at this time corresponds to the control target set temperature (second target temperature. Already already. It is determined whether or not the temperature is lower than a target temperature that is the same as or different from the above-described target temperature (for example, set according to the heating load). If the return hot water temperature is lower than the target set temperature, the determination is satisfied (S130: YES), and the routine goes to Step S135.

  In step S135, the switching control units 61p and 62p increase the rotation speed of the second compressor 53 of the air heat heat pump circuit 50 and increase the output of the air heat heat pump unit 5 as in step S35. Then, it returns to step S115 and repeats the same procedure.

  On the other hand, if the return hot water temperature is equal to or higher than the target set temperature in the determination in step S130, the determination is not satisfied (S130: NO), and the process proceeds to step S140.

  In step S140, the switching control units 61p and 62p decrease the rotation speed of the second compressor 53 of the air heat heat pump circuit 50 and reduce the output of the air heat heat pump unit 5 as in step S40. Then, it returns to step S115 and repeats the same procedure. However, when the return hot water temperature is equal to the target set temperature in the determination in step S130, the determination in step S130 is not satisfied, but it is not always necessary to reduce the rotation speed of the second compressor 53 as described above. Alternatively, the rotational speed may be maintained as it is.

  As described above, in the present embodiment, during the heating operation, the rotation speed of the first compressor 43 (in other words, in order to maintain the evaporator inlet refrigerant temperature at approximately −10 ° C. by the processing in steps S120 and S125). The output of the geothermal heat pump unit 4 is controlled), and the rotation speed (in other words, the second compressor 53) is supplemented by the processing in steps S130, S135, and S140 so as to supplement the shortage of the output of the geothermal heat pump unit 4. The output of the air heat heat pump unit 5 is controlled.

  As described above, according to the heat pump device 1 of the present embodiment, the first refrigerant temperature sensor 42b is provided, and in the underground heat pump circuit 40, the condenser outlet refrigerant temperature (during cooling operation) or the evaporator inlet Refrigerant temperature (during heating operation) is detected, and the switching controller 61p, 62p performs the first compression according to the detected refrigerant temperature and the first threshold value or the second threshold value. The rotational speed of the machine 43 is reduced.

  For example, when the condenser outlet refrigerant temperature becomes higher than 30 ° C. during the cooling operation, the rotational speed of the first compressor 43 is reduced. Thereby, in the state where the outside air temperature is high and the first compressor 43 is driven as a main power source, the underground heat pump circuit 40 is prevented from excessively operating and the underground temperature is prevented from excessively increasing. be able to. For example, when the evaporator inlet refrigerant temperature is lower than −10 ° C. during the heating operation, the rotation speed of the first compressor 43 is reduced. Accordingly, in the state where the outside air temperature is low and the first compressor 43 is driven as a main power source, the underground heat pump circuit 40 is prevented from excessively operating and the underground temperature is suppressed from being excessively lowered. be able to.

  As described above, since it is possible to suppress the geothermal heat pump circuit 40 from operating excessively during both the cooling operation and the heating operation, the efficiency of the geothermal heat pump circuit 40 (in other words, the geothermal heat pump unit) 4 can be kept high (see FIGS. 11B and 12B).

  In the present embodiment, in particular, a return liquid temperature sensor 34 is provided, and the second compressor 53 on the air heat heat pump circuit 50 side according to the detected value of the return cold water temperature (or the return hot water temperature). The number of rotations is controlled to increase. As a result, a decrease in the amount of heat exchange between the underground heat pump circuit 40 and the terminal circulation circuit 30 due to the rotational speed reduction control of the first compressor 43 is compensated by the air heat heat pump circuit side 50, and the entire apparatus is cooled. A decrease in output (or heating output) can be prevented.

  In the present embodiment, in particular, each switching control unit 61p, 62p causes the second compressor 53 when the outside air temperature detected by the outside air temperature sensor 57 is lower than 30 ° C. during the cooling operation. Is used as a main power source and the first compressor 43 is driven as an auxiliary power source. When the outside air temperature detected by the outside air temperature sensor 57 is higher than 30 ° C., each switching control unit 61p, 62p uses the first compressor 43 as a main power source and turns the second compressor 53 on. While driving as an auxiliary power source, when the condenser outlet refrigerant temperature becomes higher than 30 ° C., the rotational speed of the first compressor 43 is reduced.

  Thus, during the cooling operation, when the outside air temperature is high, the first compressor 43 is driven as a main power source, so that the ground heat exchanger circuit 40 releases the ground heat exchanger 23 greatly. The amount of heat can be secured, and the underground heat pump circuit 40 can be prevented from operating excessively at that time. As a result, the efficiency of the underground heat pump circuit 40 can be reliably kept high during the cooling operation.

  Further, in the present embodiment, in particular, each switching control unit 61p, 62p is in a state where the condenser outlet refrigerant temperature is higher than 30 ° C. and the rotational speed of the first compressor 43 is reduced during the cooling operation. When the return cold water temperature becomes higher than the target set temperature, the rotational speed of the second compressor 53 is increased. As a result, an increase in the return chilled water temperature due to a decrease in the amount of heat exchange between the geothermal heat pump circuit 40 and the terminal circulation circuit 30 is suppressed by heat radiation from the terminal circulation circuit 30 to the air heat heat pump circuit 50. Thus, it is possible to prevent the cooling output of the entire apparatus from being lowered.

  Further, in the present embodiment, in particular, each switching control unit 61p, 62p causes the second compressor 53 when the outside air temperature detected by the outside air temperature sensor 57 is higher than 5 ° C. during the heating operation. Is used as a main power source and the first compressor 43 is driven as an auxiliary power source. When the outside air temperature detected by the outside air temperature sensor 57 is lower than 5 ° C., the switching controllers 61p and 62p use the first compressor 43 as a main power source and the second compressor 53 when the outside air temperature is lower than 5 ° C. While driving as an auxiliary power source, when the evaporator inlet refrigerant temperature becomes lower than −10 ° C., the rotational speed of the first compressor 43 is reduced.

  Thus, during the heating operation, when the outside air temperature is low, the first compressor 43 is driven as a main power source, so that the large amount of heat is absorbed from the underground heat exchanger 23 by the underground heat pump circuit 40. The amount of heat can be secured, and the underground heat pump circuit 40 can be prevented from operating excessively at that time. As a result, the efficiency of the underground heat pump circuit 40 can be reliably kept high during the heating operation.

  In the present embodiment, in particular, each switching control unit 61p, 62p is in a state in which the evaporator inlet refrigerant temperature is lower than −10 ° C. and the rotation speed of the first compressor 43 is reduced during the heating operation. When the return hot water temperature becomes lower than the target set temperature, the rotational speed of the second compressor 53 is increased. As a result, a decrease in the return hot water temperature due to a decrease in the amount of heat exchange between the geothermal heat pump circuit 40 and the terminal circulation circuit 30 is suppressed by heat radiation from the air heat heat pump circuit 50 to the terminal circulation circuit 30. Can prevent a decrease in heating output of the entire device

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not change the summary of invention. For example, in the above-described embodiment, a ground heat exchanger 23 is provided in the ground or the relatively large capacity water source, and the heat medium that exchanges heat with the ground or the water source by the ground heat exchanger 23. Although H1 was circulated in the underground heat circulation circuit 20, it is not restricted to this. That is, instead of configuring such a circulation circuit, an open type pipe line may be connected to the underground heat circulation pump 22. In this case, the upstream side (pump inflow side) and the downstream side (pump outflow side) of the geothermal circulation pump 22 are connected to water sources such as the aforementioned lakes, reservoirs, wells, etc. Pumped directly by the heat circulation pump 22 and used. That is, water such as the water source is supplied to the underground heat circulation pump 22 through a pipe line (upstream pipe line) connected to the pump upstream side, and a pipe line (downstream pipe line) connected to the pump downstream side. ), And is then guided to the underground heat source heat exchanger 45 provided in the downstream pipe line to exchange heat with the first refrigerant C1, and further through the downstream pipe line, the water source. And so on.

  Further, for example, in the above-described embodiment, the case where only one underground heat exchanger 23 is provided in the ground is described as an example. However, the present invention is not limited to this, and a plurality of underground heat exchangers 23 are provided in the underground. It may be done. In that case, the plurality of underground heat exchangers 23 may be connected in parallel to each other or may be connected in series.

  Moreover, in the said embodiment, the case where this invention is applied to the composite heat source type heat pump apparatus provided with the geothermal heat pump circuit 40 using underground heat, and the air heat heat pump circuit 50 using air heat | fever one by one However, the present invention is not limited to this. That is, the present invention may be applied to a composite heat source type heat pump apparatus including the underground heat pump circuit 40 and the air heat pump circuit 50 and including three or more heat pump circuits.

1 heat pump device 20 underground heat circulation circuit (first heat pump circuit)
21 Geothermal piping 22 Geothermal circulation pump 23 Geothermal heat exchanger (heat source)
30 Terminal circulation circuit (load side circuit)
31 Load piping (circulating fluid piping)
32 Circulating fluid circulation pump (load-side circulation pump)
34 Return fluid temperature sensor (circulating fluid temperature detection means)
36 Heat exchange terminal (load terminal)
40 Geothermal heat pump circuit (first heat pump circuit)
41 1st heat exchanger (1st load side heat exchanger)
42 1st refrigerant | coolant piping 42a 1st refrigerant | coolant discharge temperature sensor 42b 1st refrigerant | coolant temperature sensor (refrigerant temperature detection means)
43 1st compressor 44 1st expansion valve 45 Underground heat source heat exchanger (1st heat source side heat exchanger)
50 Air-heat heat pump circuit (second heat pump circuit)
51 2nd heat exchanger (2nd load side heat exchanger)
52 2nd refrigerant | coolant piping 52a 2nd refrigerant | coolant discharge temperature sensor 53 2nd compressor 54 2nd expansion valve 55 Air heat source heat exchanger (2nd heat source side heat exchanger)
57 Outside air temperature sensor (outside air temperature detection means)
61 Geothermal control device 61A Compressor control unit 61B Expansion valve control unit 61C Pump control unit 61p Switching control unit (control means)
62 air heat control device 62A compressor control unit 62B expansion valve control unit 62C fan control unit 62p switching control unit (control means)
C1 First refrigerant C2 Second refrigerant H1 Heat medium L Circulating fluid

Claims (4)

The first compressor, the first load side heat exchanger, and the first heat source side heat exchanger are connected by a first refrigerant pipe, and the first heat source side heat exchanger and the predetermined heat source are connected by a heat medium pipe. Connect to form a first heat pump circuit;
A second compressor, a second load side heat exchanger, and a second heat source side heat exchanger capable of exchanging heat with the outside air are connected by a second refrigerant pipe to form a second heat pump circuit;
The first load-side heat exchanger, the second load-side heat exchanger, and the load terminal are arranged in series with the first load-side heat exchanger upstream of the second load-side heat exchanger. Connected with circulating fluid piping to form a load side circuit,
Outside temperature detecting means for detecting outside temperature;
During operation, either the first compressor or the second compressor is used as a main power source depending on whether the outside air temperature detected by the outside air temperature detecting means is higher or lower than a predetermined reference temperature. Control means for switching whether to use the auxiliary power source,
In a composite heat source heat pump device having
In the first heat pump circuit, provided is a refrigerant temperature detecting means for detecting a refrigerant temperature flowing into the first heat source side heat exchanger or flowing out of the first heat source side heat exchanger,
The control means, during cooling operation,
When the outside air temperature detected by the outside air temperature detecting means is lower than the first reference temperature, the second compressor is driven as a main power source and the first compressor is driven as an auxiliary power source,
When the outside air temperature detected by the outside air temperature detecting means is higher than the first reference temperature, the first compressor is driven as a main power source and the second compressor is driven as an auxiliary power source, and The composite heat source heat pump apparatus, wherein the rotational speed of the first compressor is reduced when the refrigerant temperature detected by the refrigerant temperature detection means becomes higher than a first threshold value . The load side circuit further includes a circulating fluid temperature detecting means for detecting a circulating fluid temperature flowing into the load side heat exchanger,
The control means includes
The circulating fluid detected by the circulating fluid temperature detecting means in a state where the refrigerant temperature detected by the refrigerant temperature detecting means is higher than the first threshold value and the rotational speed of the first compressor is reduced. The combined heat source heat pump device according to claim 1 , wherein when the temperature becomes higher than the first target temperature, the rotational speed of the second compressor is increased . The first compressor, the first load side heat exchanger, and the first heat source side heat exchanger are connected by a first refrigerant pipe, and the first heat source side heat exchanger and the predetermined heat source are connected by a heat medium pipe. Connect to form a first heat pump circuit;
A second compressor, a second load side heat exchanger, and a second heat source side heat exchanger capable of exchanging heat with the outside air are connected by a second refrigerant pipe to form a second heat pump circuit;
The first load-side heat exchanger, the second load-side heat exchanger, and the load terminal are arranged in series with the first load-side heat exchanger upstream of the second load-side heat exchanger. Connected with circulating fluid piping to form a load side circuit,
Outside temperature detecting means for detecting outside temperature;
During operation, either the first compressor or the second compressor is used as a main power source depending on whether the outside air temperature detected by the outside air temperature detecting means is higher or lower than a predetermined reference temperature. Control means for switching whether to use the auxiliary power source,
In a composite heat source heat pump device having
In the first heat pump circuit, provided is a refrigerant temperature detecting means for detecting a refrigerant temperature flowing into the first heat source side heat exchanger or flowing out of the first heat source side heat exchanger,
The control means, during heating operation,
When the outside air temperature detected by the outside air temperature detecting means is higher than a second reference temperature, the second compressor is driven as a main power source and the first compressor is driven as an auxiliary power source,
When the outside air temperature detected by the outside air temperature detecting means is lower than the second reference temperature, the first compressor is driven as a main power source and the second compressor is driven as an auxiliary power source, and A combined heat source heat pump device, wherein the number of revolutions of the first compressor is reduced when the refrigerant temperature detected by the refrigerant temperature detecting means becomes lower than a second threshold value. The load side circuit further includes a circulating fluid temperature detecting means for detecting a circulating fluid temperature flowing into the load side heat exchanger,
The control means includes
The circulating fluid detected by the circulating fluid temperature detecting means in a state where the refrigerant temperature detected by the refrigerant temperature detecting means is lower than the second threshold value and the rotational speed of the first compressor is reduced. 4. The combined heat source heat pump device according to claim 3 , wherein when the temperature becomes lower than the second target temperature, the rotational speed of the second compressor is increased.

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