JP6675083B2 - Binary heat pump device - Google Patents

Description

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

Conventionally, as shown in FIG. 10, this type of dual heat pump device includes a high-stage refrigeration cycle 1 and a low-stage refrigeration cycle 2. (For example, see Patent Document 1)
The high-stage refrigeration cycle 1 circulates a first refrigerant in a path configured by connecting a first compressor 10, a first condenser 11, a first restrictor 12, and a first evaporator 13 in series. is there.
The low-stage refrigeration cycle 2 includes a second compressor 20, a second condenser 21, a liquid receiver 22, a second throttle unit 23, and a second evaporator 24 connected in series. This is the circulation of the second refrigerant.
The first evaporator 13 and the second condenser 21 constitute a refrigerant-refrigerant heat exchanger 25, and the high-stage refrigeration cycle 1 and the low-stage refrigeration cycle 2 By connecting the first refrigerant and the second refrigerant so as to perform heat exchange, the second evaporator 24 absorbs heat from the freezing room and cools the inside of the refrigerator. As the second evaporator 24, a fin tube heat exchanger composed of aluminum fins and copper tubes is generally used.
FIG. 11 shows a structure of a conventional dual heat pump device described in Patent Document 1. As shown in FIG. 11, the conventional binary heat pump device includes a first compressor 10, a first condenser 11, a first throttle unit 12, a first housing 30 in which these are housed, and a second compressor. 20, a refrigerant-refrigerant heat exchanger 25, a liquid receiver 22, a second throttle means 23, and a second housing 31 in which these are accommodated. By being disposed below, when the circulation of the low-stage refrigeration cycle 2 is stopped, the liquefied second refrigerant in the refrigerant-refrigerant heat exchanger 25 quickly flows down to the receiver 22 by gravity.
Therefore, when a refrigerant having a low critical temperature such as carbon dioxide is used as the second refrigerant, when the circulation of the low-stage refrigeration cycle 2 is stopped, the second refrigerant is heated to the outside air and becomes a gaseous state. Therefore, the pressure increase in the low-stage refrigeration cycle 2 can be suppressed.

Japanese Patent No. 5800994

For example, in the above-described conventional configuration, in the case of a dual heat pump device that performs a heating operation of the heat medium in the first condenser 11 of the high-stage refrigeration cycle 1, the second refrigerant has a high critical temperature such as R410A. Since a refrigerant is generally used, the second refrigerant does not enter a gaseous state due to being heated by the outside air. Therefore, there is no need to store the liquefied second refrigerant in the liquid receiver 22. Instead, the second evaporator 24 performs heat exchange with the outside air, but at low outside air temperature, the moisture in the air is cooled by the second evaporator 24 and condensed on the aluminum fins and the copper tubes of the second evaporator 24. Water is generated, and the condensed water grows as frost and becomes unable to exchange heat, so that a defrosting operation is performed periodically. When this defrosting operation is performed by a so-called reverse cycle that flows from the liquid receiver 22 to the refrigerant-refrigerant heat exchanger 30, it is necessary to transport the second refrigerant above the liquid receiver 22.
However, in the conventional configuration, when performing the defrosting operation in which the second refrigerant flows from the liquid receiver 22 in the direction of the refrigerant-refrigerant heat exchanger 30, the liquefied second refrigerant remains stored in the liquid receiver 22. Therefore, there is a problem that the second refrigerant circulating in the second refrigeration circuit during the defrosting operation is insufficient.

In order to solve the conventional problems, a binary heat pump device according to the present invention includes a first refrigeration circuit that circulates a first refrigerant by connecting a compressor, a condenser, a first throttle unit, and an evaporator in a ring shape with piping. A second refrigeration circuit for circulating a second refrigerant and exchanging heat with the first refrigerant in the evaporator; a receiver in the order of an outlet side of the evaporator in the second refrigeration circuit; Means, wherein when the circulation of the second refrigerant is stopped in the second refrigeration circuit, the liquid level of the second refrigerant in the liquid receiver is changed to the liquid level of the second refrigerant in the evaporator. The liquid receiver is disposed above the surface.
Thereby, when the circulation of the second refrigerant is stopped in the second refrigeration circuit, the liquid is received such that the liquid level of the second refrigerant in the evaporator is higher than the liquid level of the second refrigerant in the liquid receiver. When a reverse cycle defrosting operation is performed, the liquid refrigerant stored in the liquid receiver flows down to the evaporator due to gravity.

  When performing the reverse cycle defrosting operation, the dual heat pump device of the present invention discharges the second liquefied refrigerant stored in the receiver by the heating operation without remaining, so that the second heat pump device performs the second defrosting operation. The shortage of the second refrigerant circulating in the refrigeration circuit can be suppressed.

Circuit diagram of refrigerant and heat medium of dual heat pump device according to Embodiment 1 of the present invention Front view showing the internal structure of the heat generation unit provided in the dual heat pump device according to Embodiment 1 of the present invention. Circuit diagram of refrigerant and heat medium when only heating operation of heat medium is performed in the first refrigeration circuit of the dual heat pump device according to Embodiment 1 of the present invention. Circuit diagram of refrigerant and heat medium when heating operation is performed on the second refrigeration circuit of the dual heat pump device according to Embodiment 1 of the present invention and heating operation is also performed on the heat medium in the first refrigeration circuit. Circuit diagram of the refrigerant and the heat medium when the second refrigeration circuit of the dual heat pump device according to Embodiment 1 of the present invention performs the cooling operation and also performs the heating operation of the heat medium in the first refrigeration circuit. Circuit diagram of the refrigerant and the heat medium in the case where the second refrigeration circuit of the dual heat pump device according to Embodiment 1 of the present invention performs simultaneous cooling and heating operations and also performs the heating operation of the heat medium in the first refrigeration circuit. Refrigerant and heat medium in the case where the indoor heat exchanger of the second refrigeration circuit of the dual heat pump device according to Embodiment 1 of the present invention is changed to perform simultaneous cooling / heating operation and also perform the heating operation of the heat medium in the first refrigeration circuit Circuit diagram of Circuit diagram of refrigerant and heat medium when defrosting operation of the outdoor heat exchanger is performed in the second refrigeration circuit of the dual heat pump device according to Embodiment 1 of the present invention. Another configuration diagram of the refrigerant and the heat medium of the dual heat pump device according to Embodiment 1 of the present invention. Circuit diagram of refrigerant and heat medium of conventional binary heat pump device Configuration diagram of refrigerant and heat medium of conventional binary heat pump device

  According to a first aspect of the present invention, a compressor, a condenser, a first throttle device, and an evaporator are connected in a ring shape by a pipe, a first refrigeration circuit for circulating a first refrigerant, and a second refrigerant are circulated. A second refrigeration circuit for exchanging heat with the first refrigerant, a liquid receiver in order on the outlet side of the evaporator of the second refrigeration circuit, and second throttle means. When the circulation of the second refrigerant is stopped, the liquid receiver is arranged such that the liquid level of the second refrigerant in the liquid receiver is higher than the liquid level of the second refrigerant in the evaporator. It is to be arranged.

Thereby, when the circulation of the second refrigerant is stopped in the second refrigeration circuit, the liquid is received such that the liquid level of the second refrigerant in the evaporator is higher than the liquid level of the second refrigerant in the liquid receiver. When the defrosting operation is performed in the reverse cycle, the liquid refrigerant stored in the receiver flows down toward the evaporator due to gravity.
Therefore, when the reverse cycle defrosting operation is performed, the liquefied second refrigerant stored in the receiver by the heating operation is discharged without remaining, and the second refrigerant circulating in the second refrigeration circuit during the defrosting operation is discharged. Shortage of the refrigerant can be suppressed.

  The lower end of the liquid receiver is disposed above the upper end of the evaporator.

Thus, when performing the reverse cycle defrosting operation, the liquid refrigerant stored in the receiver flows down toward the evaporator due to gravity.
Therefore, when performing the reverse cycle defrosting operation, the liquefied second refrigerant stored in the receiver by the heating operation is discharged without remaining, and the second refrigerant circulating in the second refrigeration circuit during the defrosting operation is discharged. Shortage of the refrigerant can be suppressed.

  According to a third aspect of the present invention, a compressor, a condenser, a first restrictor, and an evaporator are connected in a ring shape by piping, a first refrigeration circuit for circulating a first refrigerant, and a second refrigerant are circulated. A second refrigeration circuit for exchanging heat with the first refrigerant, and a liquid receiver, a second throttling means, and a control unit in order at an outlet side of the evaporator of the second refrigeration circuit. The part is for making the opening degree of the second throttle means smaller when the first refrigeration circuit is not in the heating operation than in the heating operation.

By making the opening degree of the second throttle means smaller than that in the heating operation when the first refrigeration circuit performs other than the heating operation, for example, when performing the reverse cycle defrosting operation, the second flow out of the second throttle means is performed. The refrigerant is vaporized and expanded, and the liquefied second refrigerant stored in the receiver is discharged.
Further, the second refrigerant in the low-pressure liquid state that has passed through the second throttle means is prevented from flowing into the receiver.
Therefore, even if the first refrigeration circuit performs the defrosting operation in the reverse cycle immediately before the first refrigeration circuit finishes boiling in the heating operation, the amount of the second refrigerant stored in the liquid receiver increases. The shortage of the second refrigerant circulating in the second refrigeration circuit can be suppressed by quickly discharging the refrigerant.
In addition, during the defrosting operation, it is possible to prevent the second refrigerant from being additionally stored in the liquid receiver.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by the embodiment.

(Embodiment 1)
FIG. 1 is a circuit diagram of the refrigerant and the heat medium of the dual heat pump device 500 according to the first embodiment of the present invention. In FIG. 1, a dual heat pump device 500 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 connecting a compressor 41, a condenser 42, a first throttle means 43, and an evaporator 44 in series using a refrigerant pipe 45 in sequence. A first refrigerant is circulated in 100.
On the discharge side of the compressor 41, a compressor discharge temperature detecting means 46 for detecting the temperature of the first refrigerant discharged from the compressor 41 is provided. On the suction side of the compressor 41, a compressor suction temperature detecting means 47 for detecting the temperature of the first refrigerant sucked from the compressor 41 is provided. Further, on the suction side of the compressor 41, a compressor suction pressure detecting means 48 for detecting the pressure of the first refrigerant sucked from the compressor 41 is provided. Further, the evaporator 44 is provided with a second refrigeration circuit evaporator intermediate temperature detecting means 49 for detecting an intermediate temperature of the evaporator 44 in the second refrigeration circuit 102.
The evaporator 44 is a refrigerant-refrigerant heat exchanger for exchanging heat between the first refrigerant and the second refrigerant, and uses a plate heat exchanger or a double-pipe heat exchanger.

The heat medium circuit 104 has a structure in which a heat medium storage means 50, a heat medium transport means 51 such as a pump, for example, and a condenser 42 are sequentially connected in series by a pipe 52. Circulates a heat medium.
The condenser 42 is a heat medium-refrigerant heat exchanger for exchanging heat between the first refrigerant and the heat medium, and includes a plate heat exchanger, a double tube heat exchanger, and a shell tube heat exchanger.

  The second refrigeration circuit 102 includes a second compressor 53, indoor heat exchangers 54a and 54b that perform heat exchange with indoor air, and an indoor heat exchanger opening / closing means disposed at one inlet of the indoor heat exchangers 54a and 54b. 55a, 55b, 55c, 55d; throttle means 56a, 56b for the indoor heat exchanger provided at the other inlet of the indoor heat exchangers 54a, 54b; an outdoor heat exchanger 57 for exchanging heat with outdoor air; an outdoor heat exchange The outdoor heat exchanger opening / closing means 58a, 58b provided at one inlet of the heat exchanger 57 and the outdoor heat exchanger throttle means 59 provided at the other inlet of the outdoor heat exchanger 57 are connected in series by the second refrigerant pipe 60. The configuration is connected to.

  Further, evaporator opening / closing means 61a, 61b, evaporator 44, third throttle means 62, liquid receiver 63, and second throttle means 64 provided at one inlet of evaporator 44 are sequentially connected in series. . These evaporator opening / closing means 61a, 61b, evaporator 44, third throttle means 62, liquid receiver 63, and second throttle means 64 comprise indoor heat exchangers 54a, 54b, indoor heat exchanger opening / closing means 55a, 55b, 55c. , 55d and throttle means 56a, 56b for the indoor heat exchanger are connected in parallel by a second refrigerant pipe 60. The second refrigerant is circulated in the second refrigeration circuit 102.

  As the first refrigerant, a natural refrigerant such as carbon dioxide (CO2) is used in addition to a chlorofluorocarbon-based refrigerant such as R22, R410A, R407C, R32, and R134a. Carbon (CO2) is desirable.

  In addition, as the second refrigerant, a refrigerant having a high critical temperature such as a chlorofluorocarbon-based refrigerant such as R22, R410A, R407C, R32, or R134a is used. The second refrigerant is in a gaseous state, so that the pressure in the second refrigeration circuit 102 does not excessively increase.

  In particular, when carbon dioxide having a low critical temperature is used as the first refrigerant, the temperature difference between the condensation temperature of the second refrigerant and the evaporation temperature of the second refrigerant increases, so that the second refrigerant is supercooled at the outlet of the evaporator 44. Since the temperature increases and the density of the second refrigerant in the liquid state increases, the liquid receiver 63 is required.

  On the discharge side of the second compressor 53, a second compressor discharge pressure detecting means 65 for detecting the pressure of the second refrigerant discharged from the second compressor 53 is provided. On the side, a second compressor suction pressure detecting means 66 for detecting the pressure of the second refrigerant sucked into the second compressor 53 is provided.

Between each indoor heat exchanger 54a, 54b and each indoor heat exchanger opening / closing means 55a, 55b, 55c, 55d, an indoor heat exchanger first temperature detecting means 67a, 67b for detecting the temperature of the second refrigerant is provided. A second indoor heat exchanger temperature detecting means 68a, 68b for detecting the temperature of the second refrigerant is provided between each indoor heat exchanger 54a, 54b and each indoor heat exchanger throttle means 56a, 56b. Have been.
Further, between the outdoor heat exchanger 57 and the outdoor heat exchanger opening / closing means 58a, 58b, an outdoor heat exchanger first temperature detecting means 69 for detecting the temperature of the second refrigerant, and the outdoor heat exchanger 57 and the outdoor heat exchanger An outdoor heat exchanger second temperature detecting means 70 for detecting the temperature of the second refrigerant is provided between the heat exchanger throttle means 59.

A second refrigeration circuit evaporator outlet temperature detecting means 71 for detecting the temperature of the second refrigerant is provided between the evaporator 44 and the third throttle means 62.
A second refrigeration circuit intermediate pressure detecting means 72 for detecting the pressure of the second refrigerant and a second refrigeration circuit intermediate temperature detecting means 73 for detecting the temperature of the second refrigerant are provided at the outlet side of the second throttle means 64, respectively. Have been.
Further, between the condenser 42 and the heat medium transport means 51, a heat medium condenser inlet temperature detecting means 74 for detecting the temperature of the heat medium flowing into the condenser 42 is provided.
Further, between the condenser 42 and the heat medium storage means 50, a heat medium condenser outlet temperature detection means 75 for detecting the temperature of the heat medium flowing into the condenser 42 is provided.

Further, the dual heat pump device 500 of the present embodiment includes the control unit 200 as a control unit of the first refrigeration circuit 100, the second refrigeration circuit 102, and the heat medium circuit 104.
The control unit 200 can be realized using one or a plurality of microcomputers. In this case, the microcomputer may have a configuration including, for example, a CPU, a ROM, a flash memory, and a RAM. The CPU executes a computer program stored in the ROM while using the RAM as a work area, and executes the first refrigeration circuit 100, Each part of the second refrigeration circuit 102 and the heat medium circuit 104 is generally controlled.
The control unit 200 sets the opening degree of the second throttle unit 64 at a time other than when the first refrigeration circuit 100 is operated for heating, based on the opening degree of the second throttle unit 64 during the heating operation of the first refrigeration circuit 100. Is also controlled to be small.

FIG. 2 is a front view showing the internal structure of the heat generation unit 300 provided in the dual heat pump device 500 according to the first embodiment of the present invention.
The heat generation unit 300 includes a casing 305, and the following are arranged inside the casing 305. That is, the first refrigeration circuit 100 constituted by the compressor 41, the condenser 42, the first throttle means 43, and the evaporator 44, and the heat medium constituted by the heat medium transfer means 51 and the pipe 52. The medium circuit 104 and the casing 305 are the second refrigeration circuit 102 including the second refrigerant pipe 60, the third throttle unit 62, the liquid receiver 63, and the second throttle unit 64.

  As shown in FIG. 2, at a corner of the casing 305, a support table 111 that supports the heat medium transport unit 51 is arranged. On the support 111, the heat medium transporting means 51 is arranged. A compressor support 112 for supporting the compressor 41 is arranged next to the support 111. On the compressor support 112, the compressor 41 is arranged.

An evaporator base 301 for installing the evaporator 44 on the upper surface is arranged near the compressor support base 112 and the compressor 41. Further, the position of the evaporator base 301 is also a corner on the side opposite to the side where the support base 111 is arranged when the dual heat pump is viewed from the front. The evaporator base 301 is fixed to the side plate member 113 of the casing 305.
The condenser 42 is disposed below the evaporator base 301. On the upper surface of the evaporator base 301, the evaporator 44 is arranged.

Above the evaporator mount 301, a liquid receiver mount 302 on which the liquid receiver 63 is installed is disposed. The receiver base 302 is fixed to the side plate member 113 of the casing 305.
The liquid receiver 63 is arranged on the upper surface of the liquid receiver base 302.
As described above, the evaporator 44 is disposed below the receiver base 302 with the receiver base 302 therebetween, and the receiver 63 is disposed on the upper surface of the receiver base 302. The lower end 63A of the liquid receiver 63 is disposed above the upper end 44A of the evaporator 44.

The second refrigerant is stored in the liquid receiver 63. The liquid level of the second refrigerant stored in the liquid receiver 63 is shown in FIG. The liquid level of the second refrigerant in the evaporator 44 is shown in FIG.
The liquid receiver 63 is configured such that the liquid level A of the second refrigerant in the liquid receiver 63 when the circulation of the second refrigerant is stopped in the second refrigeration circuit 102 is higher than the liquid level B of the second refrigerant in the evaporator 44. It suffices if it is installed so that it is also above.

The operation and operation of the dual heat pump device 500 configured as described above will be described below.
First, FIG. 3 is a circuit diagram of the refrigerant and the heating medium when only the heating operation of the heating medium is performed in the first refrigeration circuit 100 of the dual heat pump device 500 according to Embodiment 1 of the present invention. Note that, in the description of FIG. 3, the opening / closing means whose inside is painted black indicates a closed state (the same applies hereinafter).
As shown in FIG. 3, when only the heating operation of the heat medium is performed in the first refrigeration circuit 100, the second refrigerant discharged from the second compressor 53 evaporates through the evaporator opening / closing means 61b in the open state. Into the vessel 44. In the first refrigeration circuit 100, the first refrigerant discharged from the compressor 41 radiates heat to the heat medium in the condenser 42, and based on the temperature detected by the compressor discharge temperature detecting means 46, the first throttle means 43. And flows into the evaporator 44, absorbs heat from the second refrigerant, and is sucked into the compressor 41. The heat medium is conveyed from the lower part of the heat medium storage means 50 to the condenser 42 by the heat medium conveyance means 51, and is heated by the heat of the first refrigerant in the condenser 42, and is stacked from the upper part of the heat medium storage means 50. Will be stored.

The second refrigerant absorbed by the first refrigerant in the evaporator 44 passes through the third throttle unit 62 which is fully opened, and then has an amount based on the pressure and temperature of the second refrigerant flowing out of the evaporator 44. The two refrigerants are stored in the receiver 63. The second refrigerant flowing out of the receiver 63 has a condensing temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 65 and a temperature detected by the second refrigeration circuit evaporator outlet temperature detecting means 71. Is narrowed by the second throttle means 64 based on the degree of supercooling determined from the difference between The second refrigerant that has flowed out of the second throttle means 64 has an evaporation temperature calculated from the pressure detected by the second compressor suction pressure detecting means 66 by the outdoor heat exchanger throttle means 59 and the second heat exchanger first heat exchanger. The amount of heat flowing through the outdoor heat exchanger 57 is adjusted based on the degree of superheat determined from the temperature difference detected by the temperature detecting means 69, and the outdoor heat exchanger 57 absorbs heat from outdoor air.
Then, the second refrigerant flowing out of the outdoor heat exchanger 57 passes through the open / close means 58a for the outdoor heat exchanger in the open state and is sucked into the second compressor 53. In this case, the evaporator opening / closing means 61a, the indoor heat exchanger opening / closing means 55b, 55d, the outdoor heat exchanger opening / closing means 58b, and the indoor heat exchanger throttle means 56a, 56b are closed, so that the second refrigerant does not flow. It has become.
The indoor heat exchanger opening / closing means 55a and 55c are opened so that the second refrigerant does not accumulate in the indoor heat exchangers 54a and 54b.

Next, FIG. 4 shows the refrigerant and the heat medium in the case where the second refrigeration circuit 102 of the dual heat pump device 500 according to Embodiment 1 of the present invention performs the heating operation and the first refrigeration circuit 100 also performs the heating operation of the heat medium. FIG.
As shown in FIG. 4, when the second refrigeration circuit 102 performs the heating operation using the indoor heat exchangers 54 a and 54 b as a condenser and also performs the heating operation of the heat medium in the first refrigeration circuit 100, the second compression is performed. The second refrigerant discharged from the unit 53 flows into the indoor heat exchangers 54a, 54b through the open / close means 55b, 55d for the indoor heat exchanger in the open state, and radiates heat to the indoor air at the indoor heat exchangers 54a, 54b. I do. In the first refrigeration circuit 100, the first refrigerant discharged from the compressor 41 radiates heat to the heat medium in the condenser 42, and the first refrigerant is discharged based on the temperature detected by the compressor discharge temperature detecting means 46. It is throttled by the means 43 and flows into the evaporator 44, absorbs heat from the second refrigerant flowing into the evaporator 44 through the evaporator opening / closing means 61 b in the open state, and is sucked into the compressor 41. The heat medium is conveyed from the lower part of the heat medium storage means 50 to the condenser 42 by the heat medium conveyance means 51, and is heated by the heat of the first refrigerant in the condenser 42, and then stacked from the heat medium storage means 50 in a stacked manner. Will be stored.

On the other hand, the second refrigerant absorbed by the first refrigerant in the evaporator 44 passes through the third opening means 62 which is fully open, and then has an amount based on the pressure and temperature of the second refrigerant flowing out of the evaporator 44. The two refrigerants are stored in the receiver 63. The second refrigerant flowing out of the receiver 63 has a condensing temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 65 and a temperature detected by the second refrigeration circuit evaporator outlet temperature detecting means 71. Is narrowed by the second throttle means 64 based on the degree of supercooling determined from the difference between The second refrigerant flowing out of the indoor heat exchangers 54a and 54b is condensed by the condensing temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 65, and the second refrigerant is detected by the indoor heat exchanger second temperature detecting means 68a and 68b. Based on the degree of supercooling, which is obtained from the difference between the detected temperature and the degree of subcooling, the refrigerant is throttled by the indoor heat exchanger throttle means 56a and 56b and then merges with the second refrigerant flowing out of the second throttle means 64 to perform outdoor heat exchange. The heat is absorbed from the outdoor air by the vessel 57. The outdoor heat exchanger throttle means 59 is obtained from the difference between the evaporation temperature calculated from the pressure detected by the second compressor suction pressure detection means 66 and the temperature detected by the outdoor heat exchanger first temperature detection means 69. The second refrigerant flowing through the outdoor heat exchanger 57 is adjusted based on the degree of superheat.
Then, the second refrigerant flowing out of the outdoor heat exchanger 57 passes through the open / close means 58a for the outdoor heat exchanger in the open state and is sucked into the second compressor 53. In this case, the evaporator opening / closing means 61a, the indoor heat exchanger opening / closing means 55a and 55c, and the outdoor heat exchanger opening / closing means 58b are closed, so that the second refrigerant does not flow.

FIG. 5 is a diagram showing the refrigerant and heat medium in the case where the second refrigeration circuit 102 of the dual heat pump device 500 according to Embodiment 1 of the present invention performs the cooling operation and the first refrigeration circuit 100 also performs the heating operation of the heat medium. It is a circuit diagram.
As shown in FIG. 5, when the second refrigeration circuit 102 performs the cooling operation using the indoor heat exchangers 54 a and 54 b as the evaporator and also performs the heating operation of the heat medium in the first refrigeration circuit 100, the second compression is performed. The second refrigerant discharged from the unit 53 flows into the outdoor heat exchanger 57 through the open / close means 58b for the outdoor heat exchanger in the open state, and radiates heat to the outdoor air. In the first refrigeration circuit 100, similarly to the heating operation of the second refrigeration circuit 102, the first refrigerant discharged from the compressor 41 radiates heat to the heat medium in the condenser 42, and is discharged by the compressor discharge temperature detecting means 46. Based on the detected temperature, it is throttled by the first throttle means 43 and flows into the evaporator 44, and absorbs heat from the second refrigerant flowing into the evaporator 44 through the evaporator opening / closing means 61 b in the open state to compress the compressor 41. Inhaled. The heat medium is conveyed from the lower part of the heat medium storage means 50 to the condenser 42 by the heat medium conveyance means 51, and is heated by the heat of the first refrigerant in the condenser 42, and then stacked from the heat medium storage means 50 in a stacked manner. Will be stored.

The second refrigerant absorbed by the first refrigerant in the evaporator 44 passes through the third throttle unit 62 which is fully opened, and then has an amount based on the pressure and temperature of the second refrigerant flowing out of the evaporator 44. The two refrigerants are stored in the receiver 63. The second refrigerant flowing out of the receiver 63 has a condensing temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 65 and a temperature detected by the second refrigeration circuit evaporator outlet temperature detecting means 71. Is narrowed by the second throttle means 64 based on the degree of supercooling determined from the difference between The second refrigerant flowing out of the outdoor heat exchanger 57 has a condensing temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 65 and a temperature detected by the outdoor heat exchanger second temperature detecting means 70. And the second refrigerant flowing out of the second throttle means 64 after being throttled by the outdoor heat exchanger throttle means 59 based on the degree of supercooling determined from the difference from the indoor air in the indoor heat exchangers 54a and 54b. Endothermic. The indoor heat exchanger throttling means 56a and 56b are provided for calculating the evaporation temperature calculated from the pressure detected by the second compressor suction pressure detecting means 66 and the temperature detected by the indoor heat exchanger first temperature detecting means 67a and 67b. The second refrigerant flowing through the indoor heat exchangers 54a and 54b is adjusted based on the respective degrees of superheat determined from the difference in
The second refrigerant flowing out of the indoor heat exchangers 54a and 54b passes through the open / close means 55a and 55c for the indoor heat exchanger and is sucked into the second compressor 53. In this case, the evaporator opening / closing means 61a, the indoor heat exchanger opening / closing means 55b, 55d, and the outdoor heat exchanger opening / closing means 58a are closed, so that the second refrigerant does not flow.
FIG. 6 shows a refrigerant and a heat medium when the second refrigeration circuit 102 of the dual heat pump device 500 according to Embodiment 1 of the present invention is operated simultaneously with cooling and heating, and the first refrigeration circuit 100 also performs a heating operation on the heat medium. FIG.

  As shown in FIG. 6, the second refrigeration circuit 102 is operated simultaneously with cooling and heating by using the indoor heat exchanger 54a as a condenser and the indoor heat exchanger 54b as an evaporator. When the heating operation is also performed, the second refrigerant discharged from the second compressor 53 flows into the indoor heat exchanger 54a through the open / close means 55b for the indoor heat exchanger in the open state, and radiates heat to the indoor air. In the first refrigeration circuit 100, the first refrigerant discharged from the compressor 41 radiates heat to the heat medium in the condenser 42, and the first refrigerant is discharged based on the temperature detected by the compressor discharge temperature detecting means 46. It is throttled by the means 43 and flows into the evaporator 44, absorbs heat from the second refrigerant flowing into the evaporator 44 through the evaporator opening / closing means 61 b in the open state, and is sucked into the compressor 41. The heat medium is conveyed from the lower part of the heat medium storage means 50 to the condenser 42 by the heat medium conveyance means 51, and is heated by the heat of the first refrigerant in the condenser 42, and then stacked from the heat medium storage means 50 in a stacked manner. Will be stored.

The second refrigerant absorbed by the first refrigerant in the evaporator 44 has a condensing temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 65 and a second refrigeration circuit evaporator outlet temperature detection. After being throttled by the third throttle means 62 based on the degree of supercooling determined from the difference from the temperature detected by the means 71, it flows through the liquid receiver 63 and the fully opened second throttle means 64. The second refrigerant flowing out of the indoor heat exchanger 54a has a condensing temperature calculated from the pressure detected by the second compressor discharge pressure detecting means 65 and a temperature detected by the indoor heat exchanger second temperature detecting means 68a. After being throttled by the indoor heat exchanger throttle means 56a based on the degree of supercooling determined from the difference between the two, they are merged, and the indoor heat exchanger 54a and the outdoor heat exchanger 57 absorb heat from indoor air and outdoor air. The throttle means 56b for the indoor heat exchanger and the throttle means 59 for the outdoor heat exchanger are provided with an evaporation temperature calculated from the pressure detected by the second compressor suction pressure detecting means 66, and an indoor heat exchanger first temperature detecting means 67b. And the second refrigerant flowing through the indoor heat exchanger 54b and the outdoor heat exchanger 57 is adjusted based on the degree of superheat determined from the difference between the temperatures detected by the outdoor heat exchanger first temperature detecting means 69. I do.
The second refrigerant flowing out of the indoor heat exchanger 54b and the outdoor heat exchanger 57 passes through the open / close means 55c for the indoor heat exchanger and the open / close means 58a for the outdoor heat exchanger in the open state, and passes through the second compressor 53. Inhaled. In this case, the evaporator opening / closing means 61a, the indoor heat exchanger opening / closing means 55a and 55d, and the outdoor heat exchanger opening / closing means 58b are closed, so that the second refrigerant does not flow.

FIG. 7 shows that the indoor heat exchanger of the second refrigeration circuit 102 of the dual heat pump device 500 according to Embodiment 1 of the present invention is changed to perform simultaneous cooling and heating operation, and also perform the heating operation of the heat medium in the first refrigeration circuit 100. It is a circuit diagram of a refrigerant | coolant and a heat carrier in the case.
As shown in FIG. 7, the second refrigeration circuit 102 is simultaneously operated for cooling and heating using the indoor heat exchanger 54 a as an evaporator and the indoor heat exchanger 54 b as a condenser, and the first refrigeration circuit 100 When the heating operation is also performed, the open / close means 55a, 55d for the indoor heat exchanger are opened, the open / close means 55b, 55c for the indoor heat exchanger are closed, and the open / close state of the open / close means 58a, 58b for the outdoor heat exchanger is changed. Drive.

FIG. 8 is a circuit diagram of the refrigerant and the heat medium when performing the defrosting operation of outdoor heat exchanger 57 in second refrigeration circuit 102 of dual heat pump device 500 according to Embodiment 1 of the present invention.
As shown in FIG. 8, when performing the defrosting operation in the second refrigeration circuit 102 using the outdoor heat exchanger 57 as a condenser, the second refrigerant discharged from the second compressor 53 is in an open outdoor state. It flows into the outdoor heat exchanger 57 through the heat exchanger opening / closing means 58b and dissipates heat to the frost attached to the surface of the outdoor heat exchanger 57 to melt the frost and perform defrosting.
The second refrigerant that has passed through the outdoor heat exchanger 57 has an opening degree 59 for the outdoor heat exchanger, an opening degree of the indoor heat exchanger 56a, 56b, an opening degree of the indoor heat exchanger 54a, 54b, and an opening degree slightly smaller than the full opening. Then, the refrigerant flows through the indoor heat exchanger opening / closing means 55 a and 55 c sequentially, and is sucked into the second compressor 53. At that time, the first refrigeration circuit 100 and the heat medium circuit 104 stop.
The second throttle means 64 has a small opening so that the second refrigerant does not flow.
When the first refrigeration circuit 100 performs the heating operation, the second refrigerant stored in the liquid receiver 63 passes through the third opening means 62 which is fully open, and flows through the opening / closing means 61a for the evaporator in the open state. It is sucked into the second compressor 53.
In this case, the evaporator opening / closing means 61b, the indoor heat exchanger opening / closing means 55b, 55d, and the outdoor heat exchanger opening / closing means 58a are closed, so that the second refrigerant does not flow.

In the operating state as described above, in particular, when the second refrigerant is a fluorocarbon-based refrigerant having a high critical temperature (for example, R410A), and the first refrigerant is carbon dioxide having a low critical temperature, and the evaporating temperature is lower than the critical point, When only the heating operation of the first refrigeration circuit 100 is performed, the temperature difference between the first refrigerant and the second refrigerant in the evaporator 44 increases, and the degree of supercooling of the second refrigerant flowing out of the evaporator 44 increases. In that case, the density of the second refrigerant increases, and the amount of the liquefied second refrigerant stored in the receiver 63 increases.
On the other hand, when the defrosting operation of the outdoor heat exchanger 57 is started in the second refrigeration circuit 102, the outdoor heat exchanger 57 having a relatively large volume in the pipe as compared with the evaporator 44 and the indoor heat exchangers 54a and 54b. Although a large amount of the second refrigerant is required to raise the pressure of the second refrigerant to increase the condensing temperature, if the liquefied second refrigerant remains stored in the receiver 63, the second refrigerant used in the outdoor heat exchanger 57 (2) Since the refrigerant is insufficient and the pressure does not increase, the condensing temperature does not increase, and the time for melting the frost in the outdoor heat exchanger 57 is prolonged. While the defrosting operation of the second refrigeration circuit 102 is being performed, the heating operation of the first refrigeration circuit 100 is stopped, so that the heated heat medium is not added. In the radiator, during the defrosting operation of the second refrigeration circuit 102, the temperature of the heat medium decreases.

  Therefore, in the present embodiment, when the circulation of the second refrigerant in the second refrigeration circuit 102 is stopped, the liquid level A of the second refrigerant in the receiver 63 changes the liquid level of the second refrigerant in the evaporator 44. The liquid receiver 63 is arranged above the surface B. That is, when the circulation of the second refrigerant is stopped in the second refrigeration circuit 102, the liquid level B of the second refrigerant in the evaporator 44 is lower than the liquid level A of the second refrigerant in the receiver 63. In the case of performing a reverse cycle defrosting operation, the liquefied second refrigerant stored in the liquid receiver 63 flows down toward the evaporator 44 due to gravity. . Further, the refrigerant from the evaporator 44 passes through the evaporator opening / closing means 61a, merges with the second refrigerant flowing out of the indoor heat exchangers 54a and 54b, is sucked into the second compressor 53, and increases the pressure of the second refrigerant. It will be.

  As described above, in the present embodiment, when the circulation of the second refrigerant in the second refrigeration circuit 102 is stopped, the liquid level A of the second refrigerant in the receiver 63 changes to the level of the second refrigerant in the evaporator 44. The liquid receiver 63 is installed above the liquid level B of the two refrigerants. That is, when the circulation of the second refrigerant is stopped in the second refrigeration circuit 102, the liquid level B of the second refrigerant in the evaporator 44 is lower than the liquid level A of the second refrigerant in the receiver 63. In the case of performing a reverse cycle defrosting operation, the liquefied second refrigerant stored in the liquid receiver 63 flows down toward the evaporator 44 due to gravity. . Further, the refrigerant from the evaporator 44 passes through the evaporator opening / closing means 61a, merges with the second refrigerant flowing out of the indoor heat exchangers 54a and 54b, is sucked into the second compressor 53, and increases the pressure of the second refrigerant. It will be.

  Accordingly, when performing the reverse cycle defrosting operation, the liquefied second refrigerant stored in the receiver 63 by the heating operation of the first refrigeration circuit 100 is discharged from the receiver 63 without remaining, The shortage of the second refrigerant circulating in the second refrigeration circuit 102 during the defrosting operation can be suppressed, and the prolongation of the defrosting operation can be suppressed, and the comfort of the device can be improved.

Further, in the present embodiment, when the first refrigeration circuit 100 is not in the heating operation, the control unit 200 makes the opening degree of the second expansion unit 64 smaller than that in the heating operation, for example, to perform the reverse cycle defrosting operation. In this case, the second refrigerant flowing out of the second throttle means 64 is vaporized and expanded, and the liquefied second refrigerant stored in the liquid receiver 63 is discharged.
Further, it is possible to prevent the second refrigerant in a low-pressure liquid state that has passed through the second throttle means 64 from flowing into the liquid receiver 63.
Therefore, the inside of the heat medium storage means 50 is almost filled with the heat medium heated in the first refrigeration circuit 100, and the temperature of the heat medium conveyed from the lower part of the heat medium storage means 50 to the condenser 42 increases, so-called boiling end. Immediately before, when the stored amount of the second refrigerant in the receiver 63 increases, even when performing the reverse cycle defrosting operation, the second refrigerant stored in the receiver 63 is quickly discharged, and the second refrigerant is discharged. The shortage of the second refrigerant circulating in the second refrigeration circuit 102 can be suppressed.
In addition, by preventing the second refrigerant from being additionally stored in the receiver 63 during the defrosting operation, it is possible to suppress a prolonged defrosting operation and improve the comfort of the device.
Further, heat absorption from the first refrigeration circuit 100 to the second refrigerant can be prevented in the evaporator 44 during the defrosting operation, and the rising of the first refrigeration circuit 100 when performing the heating operation again after the defrosting operation is accelerated, Equipment comfort can be improved.

Further, in the present embodiment, since the volume of the liquid receiver 63 is larger than the volume of the evaporator 44, the lower end 63A of the liquid receiver 63 is installed to be higher than the upper end 44A of the evaporator 44. However, for example, when the volume of the liquid receiver 63 is smaller than the volume of the evaporator 44, as shown in FIG. 9, when the circulation of the second refrigerant in the second refrigeration circuit 102 is stopped, The liquid receiver 63 may be installed such that the liquid level C of the second refrigerant in the vessel 63 is higher than the liquid level D of the second refrigerant in the evaporator 44.
At this time, the lower end 63A of the liquid receiver 63 is installed at a position lower than the upper end 44A of the evaporator 44. The liquid receiver 63 and the evaporator 44 are installed on a gantry 303.
As described above, the position of the liquid level of the second refrigerant in the liquid receiver 63 and the liquid level of the second refrigerant in the evaporator 44 are determined by the difference between the volume of the liquid receiver 63 and the volume of the evaporator 44. Although the relationship changes, the liquid receiver 63 and the evaporator 44 are installed such that the liquid level of the second refrigerant in the liquid receiver 63 is higher than the liquid level of the second refrigerant in the evaporator 44. Thereby, a similar effect can be obtained.

  Further, in the present embodiment, the opening degree of the third throttle means 62 is adjusted based on whether or not only the heating operation of the heat medium is performed in the first refrigeration circuit 100, but the second refrigeration circuit intermediate pressure is adjusted. The pressure detected by the detection means 72 or the difference between the temperature detected by the second refrigeration circuit evaporator outlet temperature detection means 71 and the temperature detected by the second refrigeration circuit intermediate temperature detection means 73 (the second refrigeration circuit intermediate temperature). By adjusting based on the (temperature difference), the amount of the second refrigerant circulating in the second refrigeration circuit 102 can be adjusted so that the efficiency of the device is optimized.

  Further, in the present embodiment, since the heating medium can be heated to a usable temperature in the condenser 42 at once by using the stacked heating medium storing means 50, even when the heating medium becomes insufficient, Replenishment can be performed in a short time, and the usability of the user can be improved.

  As described above, the binary heat pump device according to the present invention shortens the defrosting operation time of the low-stage refrigeration circuit in the binary refrigeration cycle, and includes an air conditioner, a chiller, a dryer, a hot water supply air conditioning combined device, Applicable to applications such as heaters.

41 Compressor 42 Condenser 43 First throttle means 44 Evaporator 44A Upper end of evaporator 51 Heat medium transport means 62 Third throttle means 63 Liquid receiver 63A Lower end of liquid receiver 64 Second throttle means 100 First refrigeration circuit 102 Second refrigeration circuit 104 Heat medium circuit 200 Control unit 300 Heat generation unit 305 Casing 500 Binary heat pump device A Liquid level B Liquid level

Claims (1)

The compressor, the condenser, the first throttle means, and the evaporator are connected in a ring by piping,
A first refrigeration circuit for circulating a first refrigerant,
A second refrigeration circuit that circulates a second refrigerant and exchanges heat with the first refrigerant in the evaporator;
A liquid receiver, a second restrictor, in order on the outlet side of the evaporator of the second refrigeration circuit;
And a control unit,
The control unit, in a case other than the heating operation of the first refrigeration circuit, in the second refrigeration circuit having the second restriction unit, the second restriction unit, the liquid receiver, and the evaporator in this order. when the defrosting operation by the reverse cycle refrigerant flows include binary heat pump apparatus according to claim to Rukoto smaller than during the heating operation the opening of the second throttle means.

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