JP2018059648A - Dual heat pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dual heat pump device that can prevent liquid return to an air conditioning compressor by absorbing a surplus of an air conditioning refrigerant, and can improve reliability of equipment.SOLUTION: A dual heat pump device comprises: a first refrigerating circuit that connects a compressor, a condenser, first throttling means, and an evaporator with a pipe, and circulates a first refrigerant; a second refrigerating circuit that circulates a second refrigerant, and exchanges heat with the first refrigerant in the evaporator; and a heat medium circuit that circulates a heat medium, and exchanges heat with the first refrigerant in the condenser. A liquid receiver 19 and second throttling means 20 are sequentially connected to the second refrigerating circuit on the side of an outlet of the evaporator.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a binary heat pump device that adjusts the amount of refrigerant circulating in a circuit according to the operating state of a terminal in a low-stage cycle of a binary refrigeration cycle.

Conventionally, a dual heat pump apparatus including an air conditioning refrigeration cycle, a hot water supply refrigeration cycle, and a heat medium circuit is known.
As such a dual heat pump device, for example, a compressor for air conditioning, a flow path switching means, an outdoor heat exchanger, an indoor heat exchanger, and a throttle means for air conditioning are connected in series, and a refrigerant-refrigerant heat exchanger An air-conditioning refrigeration cycle for circulating air-conditioning refrigerant in a first refrigerant circuit connected in series to a hot water supply heat source throttle means and connected in parallel to the indoor heat exchanger and the air-conditioning throttle means, and a hot water supply compressor, A hot water supply refrigeration cycle that circulates the hot water supply refrigerant in a second refrigerant circuit in which the heat medium-refrigerant heat exchanger, the hot water supply throttling means, and the refrigerant-refrigerant heat exchanger are connected in series. And a hot water supply refrigeration cycle are connected by a refrigerant-refrigerant heat exchanger so that the air conditioning refrigerant and the hot water supply refrigerant exchange heat (see, for example, Patent Document 1). ).

International Publication WO2009 / 098751

Generally, a refrigerant-refrigerant heat exchanger has a higher heat transfer coefficient than an air-refrigerant heat exchanger such as an indoor heat exchanger. The volume of the exchanger is reduced.
When hot water is generated in the heat medium circuit, the enthalpy difference in the heat medium-refrigerant heat exchanger is reduced due to an increase in the incoming water temperature and the heating capacity is reduced, so the volume of the refrigerant-refrigerant heat exchanger is more than necessary. I can't make it bigger.

However, in the conventional configuration, generally, the air-conditioning refrigeration cycle includes a total heat exchanger of the air-conditioning refrigeration cycle, that is, an outdoor heat exchanger, an indoor heat exchanger, and a refrigerant-refrigerant heat exchanger. Even when all the terminals that are used are operated, the air-conditioning refrigerant is charged so as not to be insufficient, and when the number of operating terminals is small, a surplus of refrigerant occurs.
In particular, when only the heating operation of the hot water supply heat medium in the hot water supply refrigeration cycle is performed, if the incoming water temperature rises, the surplus of air conditioning refrigerant becomes excessive, and the volume of the refrigerant-refrigerant heat exchanger causes the air conditioning refrigerant. The excess of the gas cannot be absorbed, the evaporation pressure rises, and the degree of superheat of the air-conditioning refrigerant sucked into the air-conditioning compressor decreases, leading to liquid return to the air-conditioning compressor and lowering the reliability of the equipment Had the problem of doing.

  The present invention has been made in view of the above points, and can absorb the surplus of the air conditioning refrigerant, prevent liquid return to the air conditioning compressor, and improve the reliability of the device. An object is to provide a dual heat pump device.

In order to achieve the above object, a binary heat pump device according to the present invention includes a first refrigeration circuit that connects a compressor, a condenser, a first throttling means, and an evaporator with piping to circulate the first refrigerant, and a second refrigerant. A second refrigeration circuit that exchanges heat with the first refrigerant in the evaporator, and a heat medium circuit that circulates a heat medium and exchanges heat with the first refrigerant in the condenser, A liquid receiver and a second throttle means are sequentially connected to the outlet side of the evaporator of the second refrigeration circuit.
According to the present invention, when only the heating operation of the heat medium is performed in the first refrigeration circuit, the liquid second refrigerant flowing out of the evaporator can be stored in the liquid receiver, and the second refrigerant in the evaporator Even if the retained amount of the refrigerant has changed, the amount of the second refrigerant circulating in the second refrigeration circuit is reduced and the density of the second refrigerant sucked into the second compressor is stored before the second throttling means. Therefore, it is possible to suppress an increase in the pressure (evaporation pressure) of the second refrigerant sucked into the second compressor.

  According to the dual heat pump device of the present invention, in a dual refrigeration cycle having a refrigerant-refrigerant heat exchanger such as an evaporator in parallel with an air conditioning terminal having an air-refrigerant heat exchanger such as an indoor heat exchanger. When the heating medium is heated, the temperature of the heating medium flowing into the condenser rises, the heating capacity of the heating medium in the first refrigeration circuit decreases, and an excess second refrigerant is generated in the evaporator. Even when only the heating operation of the heat medium is performed in one refrigeration circuit, an increase in the evaporation pressure of the second refrigeration circuit can be suppressed, and the liquid return of the second refrigerant to the second compressor can be suppressed. Reliability can be improved.

The circuit diagram of the binary heat pump apparatus in 1st Embodiment of this invention. The circuit diagram in the case of performing only the heating operation of a heat medium in the 1st freezing circuit of the binary heat pump apparatus in 1st Embodiment of this invention. The circuit diagram in the case of heating operation of the 2nd freezing circuit of the binary heat pump apparatus in 1st Embodiment of this invention, and also performing the heating operation of a heat medium in a 1st freezing circuit. The circuit diagram at the time of carrying out the cooling operation of the 2nd freezing circuit of the binary heat pump apparatus in 1st Embodiment of this invention, and also performing the heating operation of a heat medium in a 1st freezing circuit. The circuit diagram in case the 2nd freezing circuit of the binary heat pump apparatus in 1st Embodiment of this invention carries out the cooling-heating simultaneous operation, and also performs the heating operation of a heat medium in a 1st freezing circuit. The circuit diagram in the case of changing the indoor heat exchanger of the 2nd freezing circuit of the binary heat pump apparatus in 1st Embodiment of this invention, carrying out simultaneous cooling and heating operation, and also performing the heating operation of a heat medium in a 1st freezing circuit. The flowchart which shows control of the 2nd aperture means and the 3rd aperture means in 1st Embodiment of this invention. The flowchart which shows control of the 3rd throttle means using the 2nd freezing circuit intermediate pressure in 2nd Embodiment of this invention. The flowchart which shows control of the 3rd aperture means using the 2nd freezing circuit intermediate temperature difference in 3rd Embodiment of this invention.

  According to a first aspect of the present invention, a compressor, a condenser, a first throttle means, and an evaporator are connected by piping, a first refrigeration circuit that circulates a first refrigerant, a second refrigerant is circulated, and the evaporator uses the first refrigeration circuit. A second refrigeration circuit that exchanges heat with one refrigerant, and a heat medium circuit that circulates a heat medium and exchanges heat with the first refrigerant in the condenser, and the evaporator of the second refrigeration circuit A binary heat pump device characterized in that a liquid receiver and a second throttle means are sequentially connected to the outlet side.

According to this, in the first refrigeration circuit, when only the heating operation of the heating medium is performed, the second refrigerant in the liquid state flowing out from the evaporator can be stored in the receiver, and the second refrigerant in the evaporator Even if the retained amount of the refrigerant has changed, the amount of the second refrigerant circulating in the second refrigeration circuit is reduced and the density of the second refrigerant sucked into the second compressor is stored before the second throttling means. Therefore, it is possible to suppress an increase in the pressure (evaporation pressure) of the second refrigerant sucked into the second compressor.
Thereby, when heating the heating medium in a dual refrigeration cycle having a refrigerant-refrigerant heat exchanger such as an evaporator in parallel with an air conditioning terminal having an air-refrigerant heat exchanger such as an indoor heat exchanger, The temperature of the heat medium flowing into the condenser rises, the heating capacity of the heat medium in the first refrigeration circuit decreases, and an excess second refrigerant is generated in the evaporator. Even when only the heating operation is performed, the increase in the evaporation pressure of the second refrigeration circuit can be suppressed, and the liquid return of the second refrigerant to the second compressor can be suppressed to improve the reliability of the device. it can.

  The second invention includes a control means and a third throttle means between the evaporator and the liquid receiver, and the control means circulates the heat medium circuit by the first refrigeration circuit. In the case where only the heating operation is performed, the dual heat pump is characterized in that the opening degree of the second throttle means is controlled according to the state of the second refrigerant on the outlet side of the evaporator of the second refrigeration circuit. Device.

According to this, even if the air conditioning operation of the second refrigeration circuit is performed using the indoor heat exchanger, the heating medium heating operation is performed in the first refrigeration circuit, and the air conditioning operation is stopped halfway, the third throttle By increasing the opening of the means, the pressure of the second refrigerant in the liquid receiver increases.
Therefore, when the enthalpy of the second refrigerant at the outlet of the evaporator is constant, the density of the second refrigerant in the receiver increases, and the amount of the second refrigerant stored in the receiver increases. The amount of the second refrigerant circulating in the circuit is reduced, and the evaporation pressure of the second refrigeration circuit is lowered.
Thus, even when the air conditioning and the heating medium are simultaneously heated, even if the air conditioning is stopped halfway and surplus of the second refrigerant occurs, the second refrigerant is reliably stored in the liquid receiver. By suppressing the increase in the evaporation pressure of the second refrigerant and suppressing the decrease in the degree of superheat of the second refrigerant sucked into the second compressor, the liquid return of the second refrigerant to the second compressor is suppressed, Reliability can be improved.

  In a third aspect of the invention, the control means determines whether or not the degree of supercooling of the second refrigerant on the outlet side of the evaporator is within a predetermined range after controlling the third throttling means to be fully opened. When it is determined that the degree of supercooling of the second refrigerant is within a predetermined range, the opening degree of the second throttle means is maintained, and when it is determined that the degree of supercooling is larger than the predetermined range, the opening degree of the second throttle means is set. The dual heat pump apparatus is characterized in that when it is determined that the opening degree of the second throttling means is decreased when it is increased and smaller than the predetermined range.

  According to this, the refrigerant quantity of the second refrigerant can be controlled according to the degree of supercooling of the second refrigerant on the outlet side of the evaporator.

A fourth invention is a dual heat pump device, wherein the first refrigerant is a carbon dioxide refrigerant.
According to this, when making evaporation temperature below a critical point, the temperature difference with the 2nd refrigerant | coolant in an evaporator can be enlarged. Therefore, when the condensation temperature of the second refrigerant is the same, it is possible to increase the degree of supercooling of the second refrigerant at the outlet of the evaporator as compared with a refrigerant (for example, R134a) having a relatively high evaporation temperature. Become.
Therefore, the density of the second refrigerant at the outlet of the evaporator increases, and it becomes possible to store more second refrigerant in the liquid receiver on the outlet side of the evaporator.
Further, even when only the heat medium heating operation is performed in the first refrigeration circuit at a low outside temperature, in which the amount of heat absorbed from the outside air decreases on the low pressure side of the second refrigeration circuit and the surplus of the second refrigerant increases. Increasing the density of the second refrigerant and storing more second refrigerant in the receiver to suppress the increase in the evaporation pressure of the second refrigeration circuit, and the degree of superheat of the second refrigerant sucked into the second compressor By suppressing the decrease, liquid return of the second refrigerant to the second compressor can be suppressed, the reliability of the equipment can be improved, and hot water can be generated up to a place where the temperature is high and the incoming water temperature is high. The amount of heat stored in the heat medium in the heat medium storage means can be increased.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.
(First embodiment)
FIG. 1 shows a circuit diagram of the refrigerant and the heat medium of the dual heat pump apparatus in the first embodiment of the present invention. In FIG. 1, the dual heat pump apparatus includes a first refrigeration circuit 100, a second refrigeration circuit 102, and a heat medium circuit 104.
The first refrigeration circuit 100 is configured by sequentially connecting the compressor 1, the condenser 2, the first throttling means 3 and the evaporator 4 in series with a refrigerant pipe 40. A first refrigerant is circulated through the first refrigeration circuit 100.

  A compressor discharge temperature detecting means 6 for detecting the temperature of the first refrigerant discharged from the compressor 1 is provided on the discharge side of the compressor 1, and a compressor is provided on the suction side of the compressor 1. Compressor suction temperature detection means 31 is provided for detecting the temperature of the first refrigerant sucked into 1. Further, on the suction side of the compressor 1, compressor suction pressure detection means 32 that detects the pressure of the first refrigerant sucked into the compressor 1 is provided. Further, the evaporator 4 is provided with second refrigeration circuit evaporator intermediate temperature detection means 30 for detecting the intermediate temperature of the evaporator 4 in the second refrigeration circuit 102.

The evaporator 4 is a refrigerant-refrigerant heat exchanger that exchanges heat between the first refrigerant and the second refrigerant. For example, a plate heat exchanger or a double-pipe heat exchanger is used.
The heat medium circuit 104 is configured by sequentially connecting the heat medium storage means 51, the heat medium transport means 52 including, for example, a pump, and the condenser 2 in series with a heat medium pipe 53. In 104, a heat medium is circulated.
The condenser 2 is a heat medium-refrigerant heat exchanger that exchanges heat between the first refrigerant and the heat medium. For example, a plate heat exchanger, a double tube heat exchanger, a shell tube heat exchanger, or the like is used. Used.

  The second refrigeration circuit 102 includes a second compressor 11, indoor heat exchangers 12a and 12b for exchanging heat with room air, and indoor heat exchanger opening / closing means disposed at one inlet of the indoor heat exchangers 12a and 12b. 13a, 13b, 13c, 13d, indoor heat exchanger throttling means 14a, 14b disposed at the other inlet of the indoor heat exchangers 12a, 12b, an outdoor heat exchanger 15 for exchanging heat with outdoor air, outdoor heat exchange The outdoor heat exchanger opening / closing means 16a, 16b disposed at one inlet of the condenser 15 and the outdoor heat exchanger throttle means 17 disposed at the other inlet of the outdoor heat exchanger 15 are connected in series by a second refrigerant pipe 41. Connected to and configured.

  Further, the evaporator 4, the third throttle means 18, the liquid receiver 19 and the second throttle means 20 are sequentially connected in series, and the evaporator 4, the third throttle means 18, the liquid receiver 19 and the second throttle are connected. The means 20 is constituted by connecting the indoor heat exchangers 12a and 12b, the indoor heat exchanger opening / closing means 13a, 13b, 13c and 13d, the indoor heat exchanger throttle means 14a and 14b and the second refrigerant pipe 41 in parallel. Yes. A second refrigerant is circulated through the second refrigeration circuit 102.

  Further, as the first refrigerant and the second refrigerant, natural refrigerants such as carbon dioxide (CO2) are used in addition to chlorofluorocarbon refrigerants such as R22, R410A, R407C, R32, and R134a. R407C, R134a and carbon dioxide (CO2) widely used for high temperature applications are desirable.

In addition, on the discharge side of the second compressor 11, second compressor discharge pressure detection means 21 that detects the pressure of the second refrigerant discharged from the second compressor 11 is provided. On the side, a second compressor suction pressure detecting means 22 for detecting the pressure of the second refrigerant sucked into the second compressor 11 is provided.
Between each indoor heat exchanger 12a, 12b and each indoor heat exchanger opening / closing means 13a, 13b, 13c, 13d, there are indoor heat exchanger first temperature detecting means 23a, 23b for detecting the temperature of the second refrigerant. Provided between each indoor heat exchanger 12a, 12b and each indoor heat exchanger throttling means 14a, 14b are indoor heat exchanger second temperature detecting means 24a, 24b for detecting the temperature of the second refrigerant. It has been.

An outdoor heat exchanger first temperature detecting means 25 for detecting the temperature of the second refrigerant is provided between the outdoor heat exchanger 15 and the outdoor heat exchanger opening / closing means 16a, 16b. And an outdoor heat exchanger expansion means 17 are provided with an outdoor heat exchanger second temperature detection means 26 for detecting the temperature of the second refrigerant.
Further, a second refrigeration circuit evaporator outlet temperature detecting means 28 for detecting the temperature of the second refrigerant flowing out of the evaporator 4 is provided between the evaporator 4 and the third throttle means 18.
On the outlet side of the second throttle means 20, there are a second refrigeration circuit intermediate pressure detection means 33 for detecting the pressure of the second refrigerant and a second refrigeration circuit intermediate temperature detection means 34 for detecting the temperature of the second refrigerant, respectively. Is provided.

  Further, a heat medium condenser outlet temperature detecting means 55 is provided on the outlet side of the heat medium of the condenser 2, and a heat medium condenser inlet temperature detecting means 56 is provided on the inlet side of the heat medium of the condenser 2. Is provided.

Further, the dual heat pump apparatus of the present embodiment includes a control unit 29 as a control unit for the first refrigeration circuit 100, the second refrigeration circuit 102, and the heat medium circuit 104. The control unit 29 centrally controls each unit of the heat pump apparatus, and includes a CPU, a ROM that stores an executable basic control program and data related to the basic control program, and a program executed by the CPU. And RAM for temporarily storing predetermined data, and other peripheral circuits.
In the first refrigeration circuit 100, the control unit 29 controls the driving of the compressor 1 and the first control based on the detection results by the compressor discharge temperature detection means 6, the compressor suction temperature detection means 31, and the compressor suction pressure detection means 32. The opening degree control of the 1 throttling means 3 is performed.

  In addition, in the second refrigeration circuit 102, the control unit 29 detects the detection results of the second compressor discharge pressure detection means 21 and the second compressor suction pressure detection means 22, and the indoor heat exchanger first temperature detection means 23a and 23b. The detection results of the indoor heat exchanger second temperature detection means 24a, 24b, the outdoor heat exchanger first temperature detection means 25, the outdoor heat exchanger second temperature detection means 26, and the second refrigeration circuit evaporator outlet temperature detection means 28. Based on the control, the drive control of the second compressor 11 and the opening control of the second throttle means 20, the third throttle means 18, the indoor heat exchanger throttle means 14a, 14b, and the outdoor heat exchanger throttle means 17 are performed. It is configured.

In the heat pump device configured as described above, in particular, when only the heating operation of the heat medium is performed by the first refrigeration circuit 100, the inside of the heat medium storage means 51 is substantially filled with the heated heat medium, and the heat medium storage The temperature of the heat medium rises to the lower part of the means 51. As a result, the temperature of the heat medium transported from the heat medium storage means 51 to the condenser 2 also rises, the surplus of the second refrigerant becomes excessive, and the surplus of the second refrigerant can be absorbed by the volume of the evaporator 4. Otherwise, the evaporation pressure may increase.
When the evaporation pressure in the evaporator 4 increases in this way, the degree of superheat of the second refrigerant sucked into the second compressor 11 decreases, leading to liquid return to the second compressor 11 and reducing the reliability of the equipment. There is a risk of letting you.

For this reason, in the present embodiment, the control unit 29 determines whether or not only the heating operation of the heat medium is performed in the first refrigeration circuit 100. Control to fully open.
The control unit 29 controls the third throttling unit 18 to be fully opened, and then detects the degree of supercooling SCeva_o_r2 (second compressor discharge pressure detection unit 21) of the second refrigerant at the outlet of the evaporator 4 of the second refrigeration circuit 102. It is determined whether or not the condensation temperature calculated from the pressure minus the temperature detected by the second refrigeration circuit evaporator outlet temperature detection means 28 is within a predetermined range (for example, 15K ≦ SCeva_o_r2 ≦ 20K).

  When the control unit 29 determines that the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is within a predetermined range, the control unit 29 performs control so as to maintain the opening degree of the second throttle means 20. Further, when it is determined that the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is larger than a predetermined range (for example, SCeva_o_r2> 20K), the opening degree of the second throttling means 20 is increased, and from the predetermined range When it is determined that it is small (for example, 15K> SCeva_o_r2), the second throttle means 20 is controlled so as to decrease the opening.

  By controlling in this way, when only the heating operation of the heat medium is performed in the first refrigeration circuit 100, the liquid second refrigerant flowing out of the evaporator 4 can be stored in the liquid receiver 19. Thereby, in the evaporator 4, even when the amount of the second refrigerant held changes, the second refrigerant is stored before the second throttling means 20, and the amount of the second refrigerant circulating in the second refrigeration circuit 102. And the increase in the evaporation pressure of the second refrigeration circuit 102 can be suppressed.

  In addition, when the second refrigeration circuit 102 is air-conditioned using the indoor heat exchangers 12a and 12b and the heating medium is heated by the first refrigeration circuit 100, the control unit 29 sets the second throttling means 20 to It is controlled to fully open, and it is determined whether or not the supercooling degree SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 of the second refrigeration circuit 102 is within a predetermined range (for example, 15K ≦ SCeva_o_r2 ≦ 20K).

When the control unit 29 determines that the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is within a predetermined range, the control unit 29 performs control so as to maintain the opening degree of the third throttle unit 18; When it is determined that the opening is larger than the predetermined range, the opening of the third throttle means 18 is controlled to be increased. When it is determined that the opening is smaller than the predetermined range, the opening of the third throttle means 18 is decreased. To control.
When the opening degree of the third throttling means 18 is decreased, it is preferable to set a threshold value for the minimum opening degree beforehand so as not to be fully closed.

About the dual heat pump apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.
FIG. 2 is a circuit diagram illustrating an example in which only the heating operation of the heat medium is performed in the first refrigeration circuit of the dual heat pump apparatus according to Embodiment 1 of the present invention. In FIG. 2, the black-closed opening / closing means is in a closed state (the same applies hereinafter).

As shown in FIG. 2, when only the heat medium heating operation is performed in the first refrigeration circuit 100, the second refrigerant discharged from the second compressor 11 flows into the evaporator 4.
Further, in the first refrigeration circuit 100, as in the heating operation of the second refrigeration circuit 102, the first refrigerant discharged from the compressor 1 dissipates heat by the condenser 2, and the compressor discharge temperature detection means 6 Based on the detected temperature, the first throttle means 3 squeezes and flows into the evaporator 4, absorbs heat from the second refrigerant, and is sucked into the compressor 1.
The heat medium is conveyed from the lower part of the heat medium storing means 51 to the condenser 2 by the heat medium conveying means 52, heated by the heat of the first refrigerant in the condenser 2, and then stacked from the upper part of the heat medium storing means 51. It is stored in.

The second refrigerant absorbed by the first refrigerant in the evaporator 4 is calculated from the pressure detected by the second compressor discharge pressure detecting means 21 through the fully-open third throttle means 18 and the liquid receiver 19. On the basis of the degree of supercooling obtained from the difference between the condensation temperature to be detected and the temperature detected by the second refrigeration circuit evaporator outlet temperature detection means 28, the second expansion means 20 squeezes the air to the outdoor heat exchanger 15. Absorbs heat from outdoor air.
The outdoor heat exchanger throttling means 17 is obtained from the difference between the evaporation temperature calculated from the pressure detected by the second compressor suction pressure detecting means 22 and the temperature detected by the outdoor heat exchanger first temperature detecting means 25. The 2nd refrigerant | coolant which distribute | circulates the outdoor heat exchanger 15 is adjusted based on the degree of superheated.

And the 2nd refrigerant | coolant which flowed out from the outdoor heat exchanger 15 is suck | inhaled by the 2nd compressor 11 through the open / close means 16a for outdoor heat exchangers of an open state. In this case, the indoor heat exchanger switching means 13b, 13d, the outdoor heat exchanger switching means 16b, and the indoor heat exchanger throttle means 14a, 14b are closed so that the second refrigerant does not flow.
The indoor heat exchanger opening / closing means 13a and 13c are opened so that the second refrigerant does not accumulate in the indoor heat exchangers 12a and 12b.

FIG. 3 is a circuit diagram illustrating an example in which the second refrigeration circuit of the dual heat pump apparatus according to Embodiment 1 of the present invention is operated for heating and the heating medium is also heated by the first refrigeration circuit.
As shown in FIG. 3, when the second refrigeration circuit 102 is heated using the indoor heat exchangers 12a and 12b as condensers, and the first refrigeration circuit 100 also performs the heating operation of the heat medium, the second compression is performed. The second refrigerant discharged from the machine 11 flows into the indoor heat exchangers 12a and 12b through the open indoor heat exchanger opening and closing means 13b and 13d, and radiates heat to the indoor air.

Further, in the first refrigeration circuit 100, the first refrigerant discharged from the compressor 1 dissipates heat by the condenser 2, and the first throttling means 3 based on the temperature detected by the compressor discharge temperature detecting means 6. It is throttled and flows into the evaporator 4, absorbs heat from the second refrigerant, and is sucked into the compressor 1.
The heat medium is transported from the lower part of the heat medium storage means 51 to the condenser 2 by the heat medium transport means 52, heated by the heat of the first refrigerant in the condenser 2, and then stacked from the upper part of the heat medium storage means 51. Stored.

On the other hand, the second refrigerant absorbed by the first refrigerant in the evaporator 4 includes the condensation temperature calculated from the pressure detected by the second compressor discharge pressure detection means 21 and the second refrigeration circuit evaporator outlet temperature detection means. Based on the degree of supercooling obtained from the difference from the temperature detected at 28, after being throttled by the third throttle means 18, it flows through the liquid receiver 19 and the fully opened second throttle means 20.
The second refrigerant that has flowed out of the indoor heat exchangers 12a and 12b includes the condensation temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 21, the indoor heat exchanger second temperature detecting means 24a, Based on the respective degree of supercooling obtained from the difference from the temperature detected at 24 b, the air is constricted by the indoor heat exchanger throttling means 14 a, 14 b and then merged, and the outdoor heat exchanger 15 absorbs heat from the outdoor air.
The outdoor heat exchanger throttling means 17 is obtained from the difference between the evaporation temperature calculated from the pressure detected by the second compressor suction pressure detecting means 22 and the temperature detected by the outdoor heat exchanger first temperature detecting means 25. The 2nd refrigerant | coolant which distribute | circulates the outdoor heat exchanger 15 is adjusted based on the degree of superheated.

  And the 2nd refrigerant | coolant which flowed out from the outdoor heat exchanger 15 is suck | inhaled by the 2nd compressor 11 through the open / close means 16a for outdoor heat exchangers of an open state. In this case, the indoor heat exchanger opening / closing means 13a, 13c and the outdoor heat exchanger opening / closing means 16b are closed so that the second refrigerant does not flow.

FIG. 4 is a circuit diagram showing an example in the case where the second refrigeration circuit of the dual heat pump apparatus according to Embodiment 1 of the present invention performs a cooling operation and the heating operation of the heat medium is also performed by the first refrigeration circuit.
As shown in FIG. 4, when the second refrigeration circuit 102 is air-cooled using the indoor heat exchangers 12 a and 12 b as evaporators, and the first refrigeration circuit 100 also performs the heating operation of the heat medium, the second compressor The second refrigerant discharged from the refrigerant 11 flows into the outdoor heat exchanger 15 through the open / close means 16b for the outdoor heat exchanger, and dissipates heat to the outdoor air.

Further, in the first refrigeration circuit 100, as in the heating operation of the second refrigeration circuit 102, the first refrigerant discharged from the compressor 1 dissipates heat by the condenser 2, and is detected by the compressor discharge temperature detection means 6. Based on the detected temperature, the first throttle means 3 squeezes the gas into the evaporator 4, absorbs heat from the second refrigerant, and is sucked into the compressor 1.
The heat medium is transported from the lower part of the heat medium storage means 51 to the condenser 2 by the heat medium transport means 52, heated by the heat of the first refrigerant in the condenser 2, and then stacked from the upper part of the heat medium storage means 51. Stored.

Further, the second refrigerant absorbed by the first refrigerant in the evaporator 4 has a condensation temperature calculated from the pressure detected by the second compressor discharge pressure detection means 21 and a second refrigeration circuit evaporator outlet temperature detection. Based on the degree of supercooling obtained from the difference from the temperature detected by the means 28, after being throttled by the third throttle means 18, it flows through the liquid receiver 19 and the fully opened second throttle means 20, and the outdoor heat exchanger. 15 flows in.
The second refrigerant flowing out of the outdoor heat exchanger 15 is detected by the condensation temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 21 and the outdoor heat exchanger second temperature detecting means 26. Based on the degree of supercooling obtained from the difference from the measured temperature, the air is constricted by the outdoor heat exchanger throttling means 17 and then merged, and the indoor heat exchangers 12a and 12b absorb heat from the indoor air.

The indoor heat exchanger throttling means 14a, 14b are the evaporation temperature calculated from the pressure detected by the second compressor suction pressure detecting means 22, and the temperature detected by the indoor heat exchanger first temperature detecting means 23a, 23b. The second refrigerant flowing through the indoor heat exchangers 12a and 12b is adjusted based on the degree of superheat calculated from the difference between the two.
And the 2nd refrigerant | coolant which flowed out from the indoor heat exchanger 12a, 12b is suck | inhaled by the 2nd compressor 11 through the open / close means 13a, 13c for indoor heat exchangers of an open state. In this case, the indoor heat exchanger opening / closing means 13b, 13d and the outdoor heat exchanger opening / closing means 16a are closed so that the second refrigerant does not flow.

FIG. 5 is a circuit diagram showing an example in which the second refrigeration circuit of the dual heat pump apparatus according to Embodiment 1 of the present invention is operated simultaneously with cooling and heating, and the heating operation of the heat medium is performed in the first refrigeration circuit. .
As shown in FIG. 5, the second refrigeration circuit 102 is operated simultaneously with cooling and heating using the indoor heat exchanger 12a as a condenser and the indoor heat exchanger 12b as an evaporator, and heating of the heat medium in the first refrigeration circuit 100 is performed. When the operation is also performed, the second refrigerant discharged from the second compressor 11 flows into the indoor heat exchanger 12a through the open indoor heat exchanger opening / closing means 13b and dissipates heat to the indoor air.

Further, in the first refrigeration circuit 100, the first refrigerant discharged from the compressor 1 dissipates heat by the condenser 2, and the first throttle means 3 is based on the temperature detected by the compressor discharge temperature detecting means 6. And then flows into the evaporator 4, absorbs heat from the second refrigerant, and is sucked into the compressor 1.
The heat medium is transported from the lower part of the heat medium storage means 51 to the condenser 2 by the heat medium transport means 52, heated by the heat of the first refrigerant in the condenser 2, and then stacked from the upper part of the heat medium storage means 51. Stored.

Further, the second refrigerant absorbed by the first refrigerant in the evaporator 4 has a condensation temperature calculated from the pressure detected by the second compressor discharge pressure detection means 21 and a second refrigeration circuit evaporator outlet temperature detection. After being throttled by the third throttle means 18 based on the degree of supercooling obtained from the difference from the temperature detected by the means 28, it flows through the liquid receiver 19 and the fully opened second throttle means 20.
The second refrigerant flowing out of the indoor heat exchanger 12a is detected by the condensation temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 21 and the indoor heat exchanger second temperature detecting means 24a. Based on the degree of supercooling obtained from the difference from the measured temperature, the air is constricted by the indoor heat exchanger constricting means 14a and then merged, and the indoor heat exchanger 12b and the outdoor heat exchanger 15 absorb heat from indoor air and outdoor air. .
The indoor heat exchanger throttling means 14b and the outdoor heat exchanger throttling means 17 include the evaporation temperature calculated from the pressure detected by the second compressor suction pressure detecting means 22, the indoor heat exchanger first temperature detecting means 23b, The second refrigerant flowing through the indoor heat exchanger 12b and the outdoor heat exchanger 15 is adjusted based on the degree of superheat obtained from the difference in temperature detected by the outdoor heat exchanger first temperature detection means 25.

  The second refrigerant flowing out of the indoor heat exchanger 12b and the outdoor heat exchanger 15 is sucked into the second compressor 11 through the open indoor heat exchanger opening / closing means 13c and the outdoor heat exchanger opening / closing means 16a. Is done. In this case, the indoor heat exchanger opening / closing means 13a, 13d and the outdoor heat exchanger opening / closing means 16b are closed so that the second refrigerant does not flow.

FIG. 6 shows an example in which the indoor heat exchanger of the second refrigeration circuit of the dual heat pump apparatus according to Embodiment 1 of the present invention is changed to perform simultaneous cooling and heating, and the heating medium is heated in the first refrigeration circuit. FIG.
As shown in FIG. 6, the indoor heat exchanger 12a is used as an evaporator and the indoor heat exchanger 12b is used as a condenser to simultaneously cool and heat the second refrigeration circuit, and the first refrigeration circuit 100 heats the heat medium. When the operation is also performed, the indoor heat exchanger switching means 13a and 13d are opened, the indoor heat exchanger switching means 13b and 13c are closed, and the outdoor heat exchanger switching means 16a and 16b are operated without changing the open / closed state. .

  Next, the control operation by the control unit 29 in the present embodiment will be described with reference to the flowchart shown in FIG.

In the present embodiment, as shown in FIG. 7, the control unit 29 first determines whether or not only the heating operation of the heat medium is performed in the first refrigeration circuit 100 (ST1).
When only the heating operation of the heat medium is performed (ST1: YES), the control unit 29 controls the third throttling means 18 to be fully opened (ST2), and at the outlet of the evaporator 4 of the second refrigeration circuit 102. It is determined whether or not the subcooling degree SCeva_o_r2 of the second refrigerant is within a predetermined range (ST3). If the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is within a predetermined range (ST3: YES), control is performed to maintain the opening degree of the second throttling means 20 (ST4).

  In addition, when the control unit 29 determines that the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is larger than the predetermined range (ST5: YES), the controller 29 increases the opening degree of the second throttling means 20. (ST6), and when the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is determined to be smaller than the predetermined range (ST5: NO), the opening degree of the second throttle means 20 is decreased. (ST7).

On the other hand, when performing the air conditioning operation of the second refrigeration circuit 102 using the indoor heat exchangers 12a and 12b and performing the heating operation of the heat medium in the first refrigeration circuit 100 (ST1: NO), the control unit 29 The second throttle means 20 is controlled to be fully opened (ST8), and it is determined whether or not the subcooling degree SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 of the second refrigeration circuit 102 is within a predetermined range (ST9).
When the control unit 29 determines that the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is within the predetermined range (ST9: YES), the opening degree of the third throttling means 18 is maintained. Control is performed as follows (ST10).

Further, when it is determined that the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is not within the predetermined range (ST9: NO), the control unit 29 further controls the second refrigerant at the outlet of the evaporator 4. It is determined whether or not the degree of supercooling SCeva_o_r2 is greater than a predetermined range (ST11).
When the control unit 29 determines that the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is larger than the predetermined range (ST11: YES), the opening degree of the third throttling unit 18 is increased. (ST12), and when the degree of supercooling SCeva_o_r2 of the second refrigerant at the outlet of the evaporator 4 is determined to be smaller than the predetermined range (ST11: NO), the opening degree of the third throttle means 18 is decreased. (ST13).

Thereby, when only the heating operation of the heat medium is performed in the first refrigeration circuit 100, the liquid second refrigerant flowing out of the evaporator 4 is stored in the liquid receiver 19.
Therefore, even when the amount of the second refrigerant held in the evaporator 4 changes, the second refrigerant is stored in front of the second throttling means 20, and the amount of the second refrigerant circulating in the second refrigeration circuit 102 is reduced. An increase in the evaporation pressure of the refrigeration circuit 102 is suppressed.

  As described above, in the present embodiment, the compressor 1, the condenser 2, the first throttle means 3, and the evaporator 4 are connected by the pipe 40, and the first refrigeration circuit 100 for circulating the first refrigerant, A second refrigeration circuit 102 that circulates two refrigerants and exchanges heat with the first refrigerant in the evaporator 4, and a heat medium circuit 104 that circulates the heat medium and exchanges heat with the first refrigerant in the condenser 2. The receiver 19 and the second throttle means 20 were sequentially connected to the outlet side of the evaporator 4 of the second refrigeration circuit 102.

Thus, in the first refrigeration circuit 100, when only the heating operation of the heat medium is performed, the second refrigerant in the liquid state flowing out from the evaporator 4 can be stored in the liquid receiver 19, and the evaporator 4 Even when the amount of the two refrigerants is changed, the refrigerant is stored before the second throttling means 20, and the amount of the second refrigerant circulating in the second refrigeration circuit 102 is reduced and sucked into the second compressor 11. Since the density of the second refrigerant is reduced, an increase in the pressure (evaporation pressure) of the second refrigerant sucked into the second compressor 11 can be suppressed.
This heats the heat medium in a dual refrigeration cycle having a refrigerant-refrigerant heat exchanger such as the evaporator 4 in parallel with an air conditioning terminal having an air-refrigerant heat exchanger such as the indoor heat exchangers 12a and 12b. When operating, the temperature of the heat medium flowing into the condenser 2 is increased, the heating capacity of the heat medium in the first refrigeration circuit 100 is decreased, and an excess second refrigerant is generated in the evaporator 4. Even when only the heating operation of the heat medium is performed in the refrigeration circuit 100, the increase in the evaporation pressure of the second refrigeration circuit 102 can be suppressed, and the liquid return of the second refrigerant to the second compressor 11 can be suppressed. The reliability of the equipment can be improved.

  In the present embodiment, the control unit 29 (control unit) and the third throttle unit 18 are provided between the evaporator 4 and the liquid receiver 19, and the control unit 29 is heated by the first refrigeration circuit 100. When only the heating operation of the heat medium circulating in the medium circuit 104 is performed, the degree of supercooling of the second refrigerant on the outlet side of the evaporator 4 of the second refrigeration circuit 102 is controlled after the third throttle means 18 is fully opened. The opening degree of the throttle means is controlled according to (state).

Thereby, even if the air conditioning operation of the second refrigeration circuit 102 is performed using the indoor heat exchangers 12a and 12b, the heating medium heating operation is performed in the first refrigeration circuit 100, and the air conditioning operation is stopped halfway, By increasing the opening of the third throttle means 18, the pressure of the second refrigerant in the liquid receiver 19 increases.
Therefore, when the enthalpy of the second refrigerant at the outlet of the evaporator 4 is constant, the density of the second refrigerant in the liquid receiver 19 increases, and the amount of the second refrigerant stored in the liquid receiver 19 increases. The amount of the second refrigerant circulating through the second refrigeration circuit 102 decreases, and the evaporation pressure of the second refrigeration circuit 102 decreases.
As a result, even when the air conditioning and the heating medium are simultaneously heated, even if the air conditioning stops halfway and surplus of the second refrigerant occurs, the second refrigerant is reliably stored in the receiver 19 and the second refrigeration is performed. By suppressing the increase in the evaporation pressure of the circuit 102 and suppressing the decrease in the degree of superheat of the second refrigerant sucked into the second compressor 11, the liquid return of the second refrigerant to the second compressor 11 is suppressed. Thus, the reliability of the device can be improved.

In the present embodiment, the control unit 29 determines whether or not the degree of supercooling of the second refrigerant on the outlet side of the evaporator 4 is within a predetermined range after controlling the third throttling means 18 to fully open. When the degree of supercooling of the second refrigerant is determined to be within the predetermined range, the opening degree of the second throttle means 20 is maintained, and when the degree of supercooling of the second refrigerant is determined to be larger than the predetermined range, the opening degree of the second throttle means 20 is set. If it is determined that the second throttle means 20 is smaller than the predetermined range, the second throttle means 20 is controlled to decrease the opening.
Thereby, according to the supercooling degree of the 2nd refrigerant | coolant in the exit side of the evaporator 4, the refrigerant | coolant amount of a 2nd refrigerant | coolant can be controlled.

In the present embodiment, the first refrigerant is a carbon dioxide refrigerant.
Thereby, when making evaporation temperature below a critical point, the temperature difference with the 2nd refrigerant | coolant in the evaporator 4 can be enlarged. Therefore, when the condensation temperature of the second refrigerant is the same, it is possible to increase the degree of supercooling of the second refrigerant at the outlet of the evaporator 4 as compared with a refrigerant (for example, R134a) whose evaporation temperature is relatively high. Become.
Therefore, the density of the second refrigerant at the outlet of the evaporator 4 increases, and it becomes possible to store more second refrigerant in the liquid receiver 19 on the outlet side of the evaporator 4.
In the case where only the heat medium heating operation is performed in the first refrigeration circuit 100 at a low outside temperature where the amount of heat absorbed from the outside air decreases on the low pressure side of the second refrigeration circuit 102 and the surplus of the second refrigerant increases. However, the density of the second refrigerant is increased and more second refrigerant is stored in the liquid receiver 19 to suppress the increase in the evaporation pressure of the second refrigeration circuit 102, and the second compressor 11 is sucked into the second compressor 11. By suppressing the decrease in the degree of superheat of the refrigerant, the liquid return of the second refrigerant to the second compressor 11 can be suppressed, and the reliability of the equipment can be improved, and the temperature is high and the water inlet temperature is high. Hot water generation is possible, and the heat storage amount of the heat medium in the heat medium storage means 51 can be increased.

  Further, in the present embodiment, by using the stacked heat medium storage means 51, the heat medium can be heated at a stretch to the usable temperature in the condenser 2, so even when the heat medium is insufficient, It can be replenished in a short time, and user convenience can be improved.

Next, a second embodiment of the present invention will be described.
FIG. 8 is a flowchart showing the control operation of the second embodiment.
Since the circuit diagram of the refrigeration cycle is the same as that shown in FIGS. 1 to 6 described in the first embodiment, the description thereof is omitted and the control operation of this embodiment is shown in FIGS. 1 to 6. This will be described using the reference numerals.

In the present embodiment, as shown in FIG. 8, the control unit 29 first determines whether or not only the heating operation of the heat medium is performed in the first refrigeration circuit 100 (ST21).
When only the heating operation of the heat medium is performed (ST21: YES), the control unit 29 detects the pressure Pliq detected by the second refrigeration circuit intermediate pressure detection means 33 at the outlet of the evaporator 4 of the second refrigeration circuit 102. Is determined to be within a predetermined range (ST22). For example, the predetermined range is set to 1.3 MPa <Pliq <2.0 MPa.
If the pressure Pliq at the outlet of the evaporator 4 is within a predetermined range (ST22: YES), the control unit 29 controls to maintain the opening degree of the third throttle means 18 (ST23).
In addition, when it is determined that the pressure Pliq at the outlet of the evaporator 4 is larger than the predetermined range (ST24: YES), the control unit 29 performs control so as to increase the opening degree of the third throttle means 18 (ST25). When it is determined that the pressure Pliq at the outlet of the evaporator 4 is smaller than the predetermined range (ST24: NO), control is performed so as to decrease the opening degree of the third throttle means 18 (ST26).

On the other hand, when the second refrigeration circuit 102 is air-conditioned using the indoor heat exchangers 12a and 12b and the heating medium is heated in the first refrigeration circuit 100 (ST21: NO), the control unit 29 It is determined whether or not the pressure Pliq detected by the second refrigeration circuit intermediate pressure detection means 33 at the outlet of the evaporator 4 of the second refrigeration circuit 102 is a predetermined value (ST27). The predetermined value is set to 2.0 MPa, for example.
Then, when it is determined that the pressure Pliq at the outlet of the evaporator 4 is a predetermined value (ST27: YES), the control unit 29 performs control so as to maintain the opening degree of the third throttle means 18 (ST28). .
When it is determined that the pressure Pliq at the outlet of the evaporator 4 is larger than the predetermined value (ST29: YES), the control unit 29 controls to increase the opening degree of the third throttling means 18 (ST31). When it is determined that the pressure Pliq at the outlet of the evaporator 4 is smaller than the predetermined value (ST29: NO), control is performed so as to decrease the opening degree of the third throttle means 18 (ST31).

  In the present embodiment, by controlling the opening degree of the third throttling means 18 based on the pressure Pliq at the outlet of the evaporator 4, as in the first embodiment, the device efficiency is optimized. 2 The amount of the second refrigerant circulating in the refrigeration circuit 102 can be adjusted.

Next, a third embodiment of the present invention will be described.
FIG. 9 is a flowchart showing the control operation of the third embodiment.
Since the circuit diagram of the refrigeration cycle is the same as that shown in FIGS. 1 to 6 described in the first embodiment, the description thereof is omitted and the control operation of this embodiment is shown in FIGS. 1 to 6. This will be described using the reference numerals.

In the present embodiment, as shown in FIG. 9, the control unit 29 first determines whether or not only the heating operation of the heat medium is performed in the first refrigeration circuit 100 (ST41).
When only the heating operation of the heat medium is performed (ST41: YES), the control unit 29 detects the second refrigeration circuit evaporator outlet temperature detection means 28 on the outlet side of the evaporator 4 of the second refrigeration circuit 102. The difference Tliq (second refrigeration circuit intermediate temperature difference) between the detected temperature and the temperature detected by the second refrigeration circuit intermediate temperature detection means 34 is determined.

If it is determined that the temperature difference Tliq is smaller than −20K (ST42: YES), the control unit 29 controls the opening degree of the third throttle means 18 to be decreased (ST43).
In addition, when the control unit 29 determines that the temperature difference Tliq on the outlet side of the evaporator 4 is −20K or more (ST42: NO), the control unit 29 determines whether or not the temperature difference Tliq is 0K. Is determined (ST44).
If it is determined that the temperature difference Tliq is 0K (ST44: YES), the control unit 29 controls to increase the opening of the third throttle means 18 (ST45), and the temperature difference Tliq is When it is determined that it is not 0K (ST44: NO), the control unit 29 controls to maintain the opening degree of the third throttle means 18 (ST46).

On the other hand, when performing the air conditioning operation of the second refrigeration circuit 102 using the indoor heat exchangers 12a and 12b and performing the heating operation of the heat medium in the first refrigeration circuit 100 (ST41: NO), the control unit 29 It is determined whether the temperature difference Tliq is smaller than −20K (ST47).
When it is determined that the temperature difference Tliq is smaller than −20K (ST47: YES), the control unit 29 controls the opening degree of the third throttle means 18 to be decreased (ST48).
In addition, when the control unit 29 determines that the temperature difference Tliq on the outlet side of the evaporator 4 is −20K or more (ST47: NO), the control unit 29 determines whether or not the temperature difference Tliq is 0K. Is determined (ST49).
If the temperature difference Tliq is determined to be 0K (ST49: YES), the control unit 29 controls to increase the opening of the third throttling means 18 (ST50), and the temperature difference Tliq is When it is determined that it is not 0K (ST49: NO), the control unit 29 controls to maintain the opening degree of the third throttle means 18 (ST51).

  In the present embodiment, by controlling the opening degree of the third throttling means 18 based on the temperature difference Tliq on the outlet side of the evaporator 4, the efficiency of the device is optimized as in the first embodiment. In addition, the amount of the second refrigerant circulating in the second refrigeration circuit 102 can be adjusted.

  As described above, the dual heat pump device according to the present invention suppresses liquid return of the compressor of the low-stage refrigeration circuit in the dual refrigeration cycle, and is an air conditioner, chiller, dryer, and hot water supply air-conditioning composite device. It can be applied to applications such as hot water heaters.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 1st throttle means 4 Evaporator 11 2nd compressor 12 Indoor heat exchanger 15 Outdoor heat exchanger 18 3rd throttle means 19 Liquid receiver 20 2nd throttle means 29 Control part 40 Refrigerant piping 41 Second refrigerant pipe 51 Heat medium storage means 52 Heat medium conveyance means 53 Heat medium pipe 100 First refrigeration circuit 102 Second refrigeration circuit 104 Heat medium circuit

Claims (4)

A compressor, a condenser, a first throttle means and an evaporator connected by piping, and a first refrigeration circuit for circulating the first refrigerant;
A second refrigeration circuit for circulating a second refrigerant and exchanging heat with the first refrigerant in the evaporator;
A heat medium circuit that circulates a heat medium and performs heat exchange with the first refrigerant in the condenser;
A binary heat pump apparatus, wherein a liquid receiver and a second throttle means are sequentially connected to an outlet side of the evaporator of the second refrigeration circuit. A third throttle means between the control means and the evaporator and the liquid receiver;
The control means responds to the state of the second refrigerant on the outlet side of the evaporator of the second refrigeration circuit when performing only the heating operation of the heat medium circulating in the heat medium circuit by the first refrigeration circuit. The two-way heat pump device according to claim 1, wherein an opening degree of the second throttle means is controlled.   The control means, after controlling the third throttling means to fully open, determines whether or not the degree of supercooling of the second refrigerant at the outlet side of the evaporator is within a predetermined range, and When it is determined that the degree of cooling is within a predetermined range, the opening degree of the second throttle means is maintained, and when it is determined that the degree of cooling is greater than the predetermined range, the opening degree of the second throttle means is increased, and from the predetermined range. The two-way heat pump device according to claim 2, wherein when it is determined to be small, control is performed so as to reduce the opening of the second throttle means.   The dual heat pump device according to any one of claims 1 to 3, wherein the first refrigerant is a carbon dioxide refrigerant.

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