CN115769032A

CN115769032A - Outdoor unit of refrigeration device and refrigeration device provided with same

Info

Publication number: CN115769032A
Application number: CN202080102860.XA
Authority: CN
Inventors: 石川智隆; 石原宽也; 八代崇宪; 江上诚
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2020-07-15
Filing date: 2020-07-15
Publication date: 2023-03-07
Also published as: WO2022013976A1; EP4184080A4; JPWO2022013976A1; JP7391223B2; EP4184080A1

Abstract

An outdoor unit (101) of a refrigeration device having a refrigeration mode and a defrost mode, comprising: a 1 st refrigeration cycle device (103) that circulates a 1 st refrigerant to an indoor unit (102); a 2 nd refrigeration cycle device (104) that circulates a 2 nd refrigerant; and a cascade heat exchanger (11) that performs heat exchange between the 1 st refrigerant and the 2 nd refrigerant. The 1 st refrigeration cycle device (103) has a 1 st compressor (1), a 2 nd heat exchanger (2), and a four-way valve (7) that switches the flow path direction of the 1 st refrigerant between a cooling mode and a defrosting mode. The 2 nd refrigeration cycle device 104 has a 2 nd compressor (9), a 3 rd expansion valve (5), and a 3 rd heat exchanger (6). The 2 nd heat exchanger (2) is an arrangement structure for absorbing the exhaust heat of the 3 rd heat exchanger (6).

Description

Outdoor unit of refrigeration device and refrigeration device provided with same

Technical Field

The present disclosure relates to an outdoor unit of a refrigeration apparatus and a refrigeration apparatus including the outdoor unit.

Background

A defrosting mode for melting frost attached to a cooler is provided in a refrigeration apparatus. As the defrosting method, for example, the following reverse hot gas defrosting method is known: the four-way valve changes the circulation direction of the refrigerant so that the high-temperature gas from the compressor is sent to a cooler that normally functions as an evaporator.

Japanese patent No. 5595245 (patent document 1) discloses a refrigeration apparatus that performs defrosting by a reverse hot gas defrosting method in a low-temperature side cycle of a two-cycle.

A low-temperature-side circulation use pipe described in patent document 1 connects a low-temperature-side compressor, a low-temperature-side four-way valve, a low-temperature-side intercooler, a second low-temperature-side expansion device, a low-temperature-side condenser, a first low-temperature-side expansion device, and a low-temperature-side evaporator in series to constitute a refrigerant circulation circuit. In the defrosting operation, the low-temperature-side evaporator and the low-temperature-side condenser function as condensers, and the low-temperature-side intercooler functions as an evaporator.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5595245

Disclosure of Invention

Problems to be solved by the invention

When the indoor unit of the refrigeration apparatus is defrosted in the reverse direction, the heat exchanger on the low temperature side needs to collect heat from the outside air. However, when the outside air temperature is low (for example, the outside air temperature is 0 ℃ or lower), the heat exchanger on the low temperature side cannot sufficiently obtain heat from the outside air. In this case, a sufficient defrosting effect cannot be obtained.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide an outdoor unit of a refrigeration apparatus capable of obtaining a defrosting effect even when an outside air temperature is low, and a refrigeration apparatus including the outdoor unit.

Means for solving the problems

The present disclosure provides an outdoor unit of a refrigeration apparatus having a refrigeration mode and a defrosting mode, the outdoor unit including: a 1 st refrigeration cycle device for circulating a 1 st refrigerant between an indoor unit, the indoor unit being formed by connecting a 1 st expansion valve and a 1 st heat exchanger in series; a 2 nd refrigeration cycle device that circulates a 2 nd refrigerant; and a cascade heat exchanger that exchanges heat between the 1 st refrigerant and the 2 nd refrigerant, the 1 st refrigeration cycle device including: 1 st compressor and 2 nd heat exchanger; and a four-way valve for switching a connection destination of a discharge port of the 1 st compressor and a connection destination of a suction port of the 1 st compressor so that the 1 st refrigerant flows in a forward direction in a cooling mode and the 1 st refrigerant flows in a reverse direction in a defrosting mode, wherein the forward direction is a direction toward the 1 st expansion valve via the 1 st compressor and the 2 nd heat exchanger, and the reverse direction is a direction from the 1 st compressor to the 1 st heat exchanger and from the 1 st expansion valve to the 1 st compressor via the 2 nd heat exchanger, and the 2 nd refrigeration cycle device has a 2 nd compressor, a 3 rd expansion valve, and a 3 rd heat exchanger, circulates the 2 nd refrigerant in the order of the 2 nd compressor, the 3 rd heat exchanger, the 3 rd expansion valve, and the cascade heat exchanger, and has an arrangement structure in which the 2 nd heat exchanger absorbs exhaust heat of the 3 rd heat exchanger.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present disclosure, since the 2 nd heat exchanger is configured to absorb the exhaust heat of the 3 rd heat exchanger, even when the outside air temperature is low, the function of the 2 nd heat exchanger as the evaporator in the defrosting mode can be ensured, and the defrosting effect can be obtained.

Drawings

Fig. 1 is a diagram showing a structure of a refrigeration apparatus.

Fig. 2 is a diagram showing the configuration of a control device that controls the refrigeration device.

Fig. 3 is a diagram illustrating the flow of the refrigerant in the defrosting mode of the refrigeration apparatus.

Fig. 4 is a diagram showing a structure of an integrated heat exchanger used in a refrigeration apparatus.

Fig. 5 is a diagram showing the structure of the piping of the integrated heat exchanger used in the refrigeration apparatus.

Fig. 6 is a flowchart for explaining control performed by the control device.

Fig. 7 is a diagram showing a modification 1 of the integrated heat exchanger.

Fig. 8 is a diagram showing a modification 2 of the integrated heat exchanger.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.

Fig. 1 is a diagram showing the configuration of a refrigeration apparatus 100 according to the present embodiment. The refrigeration apparatus 100 includes an outdoor unit 101, indoor units 102, and

pipes

27 and 31 connecting the outdoor unit 101 and the indoor units 102.

The outdoor unit 101 includes a 1 st refrigeration cycle device 103 on a low temperature side (low-stage side) and a 2 nd refrigeration cycle device 104 on a high temperature side (high-stage side). The 1 st refrigeration cycle device 103 and the 2 nd refrigeration cycle device 104 constitute a two-stage refrigeration cycle device. In the 1 st refrigeration cycle device 103, the 1 st refrigerant circulates. In the 2 nd refrigeration cycle device 104, the 2 nd refrigerant circulates. The 1 st refrigerant being CO ₂ And the like. The 2 nd refrigerant being CO ₂ Propane, and the like. The 1 st refrigerant on the 1 st refrigeration cycle device 103 side and the 2 nd refrigerant of the 2 nd refrigeration cycle device 104 exchange heat through the cascade heat exchanger 11. The cascade heat exchanger 11 may be a heat exchanger included in the 1 st refrigeration cycle device 103 or a heat exchanger included in the 2 nd refrigeration cycle device 104.

The indoor unit 102 includes the 1 st expansion valve 3 and the 1 st heat exchanger 4. The pipe 28 extending from the 1 st expansion valve 3 is connected to the pipe 27 facing the outdoor unit 101. The 1 st expansion valve 3 and the 1 st heat exchanger 4 are connected in series by a pipe 29. As the 1 st expansion valve 3, for example, a temperature expansion valve controlled based on the temperature of the refrigerant outlet of the 1 st heat exchanger 4 can be used. The pipe 30 extending from the 1 st heat exchanger 4 is connected to a pipe 31 facing the outdoor unit 101.

The 1 st refrigeration cycle device 103 includes a 1 st compressor 1, a 2 nd heat exchanger 2, a four-way valve 7, a refrigerant amount adjusting mechanism 10, and a controller 50. The refrigerant amount adjusting mechanism 10 includes a liquid receiver 8,

refrigerant discharge pipes

34 and 35, and a flow rate adjusting valve 45. The 1 st compressor 1 and the 2 nd heat exchanger 2 are connected so that the 1 st refrigerant circulates between the indoor unit 102 and them.

The discharge side of the 1 st compressor 1 is connected to the four-way valve 7 via a pipe 21. The suction side of the 1 st compressor 1 is connected to the four-way valve 7 via a pipe 33. A pipe 32 extending from the four-way valve 7 is connected to a pipe 31 leading to the indoor unit 102. The 2 nd heat exchanger 2 and the four-way valve 7 are connected by a pipe 22. A check valve 41 is provided between the 2 nd heat exchanger 2 and the cascade heat exchanger 11. The 2 nd heat exchanger 2 and the check valve 41 are connected by a pipe 23. The cascade heat exchanger 11 and the liquid receiver 8 are connected by a pipe 24.

The 2 nd refrigeration cycle device 104 includes a 2 nd compressor 9, a 3 rd heat exchanger 6, and a 3 rd expansion valve 5. In the 2 nd refrigeration cycle device 104, the 2 nd refrigerant circulates through the 2 nd compressor 9, the 3 rd heat exchanger 6, the 3 rd expansion valve 5, and the cascade heat exchanger 11 in this order. The 2 nd compressor 9 and the 3 rd heat exchanger 6 are connected by a pipe 47. The 3 rd heat exchanger 6 and the 3 rd expansion valve 5 are connected by a pipe 48. The 3 rd expansion valve 5 and the cascade heat exchanger 11 are connected by a pipe 49. The cascade heat exchanger 11 and the 2 nd compressor 9 are connected by a pipe 53.

The cascade heat exchanger 11 performs heat exchange between the 1 st refrigerant and the 2 nd refrigerant discharged from the 2 nd heat exchanger 2 and flowing into the liquid receiver 8. The 3 rd heat exchanger 6 functions as a condenser and radiates heat. Since the refrigerant flowing into the liquid receiver 8 is cooled by the cascade heat exchanger 11, a pressure increase in the liquid receiver 8 is suppressed.

Fig. 2 is a diagram showing the configuration of a control device 50 that controls the refrigeration apparatus. Referring to fig. 2, the control device 50 includes a processor 51, a memory 52, a communication interface, not shown, and the like. The processor 51 controls the operating frequency of the 1 st compressor 1, the connection of the four-way valve 7, and the like, in accordance with the data stored in the memory 52 and the information obtained via the communication interface.

The Memory 52 is configured to include, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash Memory. In addition, the flash memory stores an operating system, an application program, and various data. The control device 50 shown in fig. 1 is realized by the processor 51 executing an operating system and an application program stored in the memory 52. When executing the application program, various data stored in the memory 52 are referred to.

The refrigeration apparatus 100 has a cooling mode and a defrosting mode as operation modes. In the cooling mode, the refrigerant flows in the direction indicated by the arrow in fig. 1. Fig. 3 is a diagram illustrating the flow of the refrigerant in the defrosting mode of the refrigeration apparatus 100.

The four-way valve 7 exchanges a connection destination of the discharge port of the 1 st compressor 1 and a connection destination of the suction port of the 1 st compressor 1 between the cooling mode and the defrosting mode. In the cooling mode shown in fig. 1, the four-way valve 7 is connected to the 1 st compressor 1 such that the 1 st refrigerant flows in the forward direction of the 1 st expansion valve 3 through the 1 st compressor 1 and the 2 nd heat exchanger 2. The 2 nd refrigeration cycle device 104 continues to operate in any of the cooling mode and the defrosting mode.

In the defrosting mode shown in fig. 3, the four-way valve 7 is connected to the 1 st compressor 1 so that the 1 st refrigerant flows in the reverse direction from the 1 st compressor 1 to the 1 st heat exchanger 4 and from the 1 st expansion valve 3 back to the 1 st compressor 1 via the 2 nd heat exchanger 2. In the defrosting mode, the 1 st heat exchanger 4 on the indoor unit 102 side functions as a condenser. Thereby, the 1 st heat exchanger 4 is defrosted. In the defrosting mode, the 2 nd heat exchanger 2 on the outdoor unit 101 side functions as an evaporator, and gives heat to the 2 nd refrigerant to the suction side of the 1 st compressor 1.

In the defrost mode, the 2 nd heat exchanger 2 needs to pick up heat from the outside air. However, when the outside air temperature is low (for example, 0 ℃ or lower), the 2 nd heat exchanger 2 itself may be frosted. Even if the 2 nd heat exchanger 2 is not frosted, the 2 nd heat exchanger 2 may not be able to sufficiently obtain heat from the outside air when the outside air temperature is low. Therefore, in the present disclosure, the arrangement structure is adopted in which the 2 nd heat exchanger 2 absorbs the exhaust heat of the 3 rd heat exchanger 6. Specifically, the 2 nd heat exchanger 2 is provided in the vicinity of the 3 rd heat exchanger 6 of the 2 nd refrigeration cycle device 104. Since the 2 nd heat exchanger 2 is provided in the vicinity of the 3 rd heat exchanger 6, the 2 nd heat exchanger 2 functioning as an evaporator (heat collector) in the defrosting mode can absorb the exhaust heat of the 3 rd heat exchanger 6. Therefore, even when the outside air temperature is low, the 2 nd heat exchanger 2 can be made to function effectively as an evaporator. For example, in the present embodiment, the integral heat exchanger 260 is configured by the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6.

The refrigerant quantity adjusting mechanism 10 is configured to adjust the circulation quantity of the 1 st refrigerant in both the cooling mode and the defrosting mode. The liquid receiver 8 is disposed between the 2 nd heat exchanger 2 and the 1 st expansion valve 3. The

refrigerant discharge pipes

34 and 35 connect the outlet of the liquid receiver 8 to the suction port of the 1 st compressor 1. The flow rate adjustment valve 45 adjusts the flow rate of the 1 st refrigerant flowing through the

refrigerant discharge pipes

34 and 35. In addition, in the present disclosure, at least the refrigerant quantity adjusting mechanism 10 is not necessarily structured.

The outdoor unit 101 further includes

bypass passages

36 and 37 for allowing the 1 st refrigerant to flow from the 1 st expansion valve 3 to the 2 nd heat exchanger 2 without passing through the liquid receiver 8 in the defrosting mode shown in fig. 3.

The outdoor unit 101 further includes: a 2 nd expansion valve 46 provided in the

bypass passages

36 and 37; and a check valve 43 provided in the bypass passage 37 and restricting a refrigerant flow direction to a direction from the 2 nd expansion valve 46 toward the 2 nd heat exchanger 2. The 2 nd expansion valve 46 is a defrosting expansion valve that functions in the defrosting mode. The control device 50 controls the 2 nd expansion valve 46 to be in a closed state in the cooling mode. On the other hand, the controller 50 opens the 1 st expansion valve 3 on the indoor unit 102 side in the defrosting mode.

When the four-way valve 7 is switched to the state shown in fig. 3, the refrigerant circulates in the direction shown by the arrow in fig. 3 because of the presence of the check valves 41 to 43. When the cooling mode is switched to the defrosting mode, a sufficient amount of refrigerant is stored in the liquid receiver 8 of the refrigerant amount adjusting mechanism 10. In the defrosting mode, when the flow rate adjustment valve 45 is opened, the amount of the circulating refrigerant is added. Therefore, in order to set the amount of refrigerant circulating in the defrosting mode to an appropriate amount, the flow rate adjustment valve 45 may be closed at a timing when the amount of refrigerant becomes an appropriate amount. Further, since the check valve 42 is provided between the pipe 25 and the pipe 26 into which the refrigerant discharge pipe 34 branches, the refrigerant from the 1 st expansion valve 3 does not flow back toward the liquid receiver 8 even when the flow rate adjustment valve 45 is opened in the defrosting mode.

After the operation mode is switched from the cooling mode to the defrosting mode, the 2 nd refrigeration cycle device 104 also continues to operate. The 1 st refrigerant flowing from the 2 nd expansion valve 46 to the pipe 23 is branched in the direction of the 2 nd heat exchanger 2 and the direction of the cascade heat exchanger 11. The 1 st refrigerant heading for the cascade heat exchanger 11 is cooled by the cascade heat exchanger 11, and a part thereof is retained in the liquid receiver 8. The controller 50 controls the flow rate adjustment valve 45 to adjust the flow rate of the 1 st refrigerant.

Fig. 4 is a diagram showing the structures of the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6 used in the refrigeration apparatus. Fig. 5 is a diagram showing the structure of the pipes of the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6 used in the refrigeration apparatus.

Referring to fig. 4, the integral heat exchanger 260 is composed of the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6. In the integrated heat exchanger 260, the 2 nd heat exchanger 2 of the 1 st refrigeration cycle device 103 is disposed above, and the 3 rd heat exchanger 6 of the 2 nd refrigeration cycle device 104 is disposed below. The integrated heat exchanger 260 includes a plurality of fins 80. A fan 70 commonly used for the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6 is provided on the depth side of the drawing facing the fin 80. By the rotation of the fan 70, an air flow is generated from the fins 80 toward the direction facing the deep side of the drawing. Referring to fig. 5, the pipe 38 of the 2 nd heat exchanger 2 and the pipe 39 of the 3 rd heat exchanger 6 are fixed to the plurality of fins 80 in a meandering manner.

The integral heat exchanger 260 is configured such that the 2 nd heat exchanger 2 is disposed above the 3 rd heat exchanger 6, and therefore the 2 nd heat exchanger 2 easily takes in the thermal energy of the air that is discharged from the 3 rd heat exchanger 6 and rises. Further, since the common fin 80 is used in the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6, the exhaust heat of the 3 rd heat exchanger 6 can be quickly and efficiently transmitted to the 2 nd heat exchanger 2. Therefore, even when the outside air temperature is low, the function of the 2 nd heat exchanger 2 as an evaporator in the defrosting mode can be ensured, and the defrosting effect can be obtained.

In the integrated heat exchanger 260, the fins 80 are shared by the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6, but instead, fins may be provided for the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6, respectively. If so, the heat transfer effect by the common fin cannot be obtained. However, if the 2 nd heat exchanger 2 is disposed above the 3 rd heat exchanger 6, the 2 nd heat exchanger 2 easily takes in the thermal energy of the air that is discharged from the 3 rd heat exchanger 6 and rises. Therefore, even when the outside air temperature is low, the function of the 2 nd heat exchanger 2 as the evaporator in the defrosting mode can be ensured, and the defrosting effect can be obtained.

Fig. 6 is a flowchart for explaining control performed by the control device. The processing of the flowchart is repeatedly executed every time a certain time elapses or every time a predetermined condition is satisfied during the operation of the refrigeration apparatus. For example, when defrosting is performed at regular intervals, the control device 50 executes the processing of the flowchart of fig. 6 when a fixed time has elapsed since the previous defrosting of the 1 st heat exchanger 4. In the determination of the transition to the defrosting mode, the refrigerant temperature or the adhesion state of frost to the 1 st heat exchanger 4 may be detected, and the determination may be made based on the detection results.

Referring to fig. 6, when the condition for switching to the defrosting mode is satisfied, in step S1, the control device 50 switches the four-way valve 7 from the state of fig. 1 to the state of fig. 3.

Then, in step S2, the control device 50 monitors the outputs of the temperature sensor 61 and the pressure sensor 62, and determines whether or not the degree of supercooling (SC: degree of supercooling) of the 1 st refrigerant in the bypass passage 36 immediately before the 2 nd expansion valve 46 is lower than a determination value.

If SC is lower than the determination value (yes in S2), the controller 50 opens the flow rate adjustment valve 45 to add the amount of circulating refrigerant. On the other hand, when SC is equal to or greater than the determination value (S2: no), the controller 50 closes the flow rate adjustment valve 45 because the circulating refrigerant amount is sufficient.

The processing of steps S2 to S4 is repeated until it is determined in step S5 that defrosting is completed. Thereby, the amount of refrigerant circulating in the defrost mode is adjusted to an appropriate amount.

If it is determined that the defrosting is completed (yes in S5), in step S6, the controller 50 returns the four-way valve 7 to the cooling mode shown in fig. 1.

According to the refrigeration apparatus 100, the refrigerant circulation amount during defrosting can be appropriately maintained, and therefore, a decrease in defrosting capacity and an excessive increase in high pressure due to a shortage of refrigerant can be avoided. Therefore, the frost can be reliably melted in a short time, and the design pressure can be suppressed to be low.

In the case of a binary cycle including the 1 st refrigeration cycle device 103 on the low temperature side and the 2 nd refrigeration cycle device 104 on the high temperature side, the design pressure of the 1 st refrigeration cycle device 103 on the low temperature side is set low. Therefore, adjusting the refrigerant circulation amount in the defrosting mode by the refrigerant amount adjusting mechanism 10 is effective for suppressing the pressure of the 1 st refrigeration cycle device 103 on the low temperature side, and is effective when carbon dioxide or the like is applied as the 2 nd refrigerant.

(modification 1)

Fig. 7 is a diagram showing a modification 1 of the integrated heat exchanger. Referring to fig. 7, the integrated heat exchanger 261 is configured such that the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6 are arranged in a horizontal direction. The integrated heat exchanger 261 includes a plurality of fins 80 shared by the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6, similarly to the integrated heat exchanger 260. The integrated heat exchanger 261 is provided with a fan 70 on a side close to the 2 nd heat exchanger 2 of the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6.

By the rotation of the fan 70, an air flow is generated in a direction from the 3 rd heat exchanger 6 toward the 2 nd heat exchanger 2. Since the 2 nd heat exchanger 2 is located on the leeward side of the air flow with respect to the 3 rd heat exchanger 6, the heat discharged from the 3 rd heat exchanger 6 is easily collected. Further, by using the common fin 80 in the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6, the exhaust heat of the 3 rd heat exchanger 6 can be quickly and efficiently transmitted to the 2 nd heat exchanger 2. Therefore, in the defrosting mode, the 2 nd heat exchanger 2 can quickly and efficiently collect heat.

In the integrated heat exchanger 261, the arrangement positions of the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6 may be reversed. Although the 2 nd heat exchanger 2 is located on the windward side of the airflow with respect to the 3 rd heat exchanger 6, the 2 nd heat exchanger 2 shares the fin 80 with the 3 rd heat exchanger 6, and therefore the fin 80 can absorb the exhaust heat of the 3 rd heat exchanger 6.

(modification 2)

Fig. 8 is a diagram showing a modification 2 of the integrated heat exchanger. Referring to fig. 8, the integrated heat exchanger 262 is different from the integrated heat exchanger 261 shown in fig. 7 in that fins are not shared by the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6. In the integrated heat exchanger 262, the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6 are arranged in the horizontal direction, and the 2 nd heat exchanger 2 and the 3 rd heat exchanger 6 are connected by the connecting member 91.

In the integrated heat exchanger 262, the fan 70 is rotated, thereby generating an air flow in a direction from the 3 rd heat exchanger 6 toward the 2 nd heat exchanger 2. In the integrated heat exchanger 262, a heat transfer function by the shared fin cannot be obtained as compared with the integrated heat exchanger 261. However, since the 2 nd heat exchanger 2 is located on the leeward side of the air flow with respect to the 3 rd heat exchanger 6, the heat discharged from the 3 rd heat exchanger 6 is easily collected. Therefore, even when the outside air temperature is low, the function of the 2 nd heat exchanger 2 as an evaporator in the defrosting mode can be ensured, and the defrosting effect can be obtained.

(conclusion)

The present embodiment is summarized below.

The present disclosure relates to an outdoor unit (101) of a refrigeration device (100) having a refrigeration mode and a defrost mode, the outdoor unit (101) including: a 1 st refrigeration cycle device (103) that circulates a 1 st refrigerant to an indoor unit (102), the indoor unit (102) being formed by connecting a 1 st expansion valve (3) and a 1 st heat exchanger (4) in series; a 2 nd refrigeration cycle device (104) that circulates a 2 nd refrigerant; and a cascade heat exchanger (11) that exchanges heat between a 1 st refrigerant and a 2 nd refrigerant, wherein the 1 st refrigeration cycle device (103) has: a 1 st compressor (1) and a 2 nd heat exchanger (2); and a four-way valve (7) that exchanges a connection destination of a discharge port of the 1 st compressor (1) and a connection destination of a suction port of the 1 st compressor (1) so that the 1 st refrigerant flows in a forward direction in which the 1 st refrigerant flows toward the 1 st expansion valve (3) via the 1 st compressor (1) and the 2 nd heat exchanger (2) and flows in a reverse direction in which the 1 st refrigerant flows from the 1 st compressor (1) toward the 1 st heat exchanger (4) and from the 1 st expansion valve (3) back to the 1 st compressor (1) via the 2 nd heat exchanger (2) in the defrosting mode, wherein the 2 nd refrigeration cycle device has a 2 nd compressor (9), a 3 rd expansion valve (5), and a 3 rd heat exchanger (6), and circulates the 2 nd refrigerant in the order of the 2 nd compressor (9), the 3 rd heat exchanger (6), the 3 rd expansion valve (5), and the cascade heat exchanger (11), and is configured such that the 2 nd heat exchanger (2) absorbs heat rejected from the 3 rd heat exchanger (6) (see fig. 4, 5, 7, 8).

Preferably, the configuration structure is as follows: the pipe (38) through which the 1 st refrigerant flows in the 2 nd heat exchanger (2) and the pipe (39) through which the 2 nd refrigerant flows in the 3 rd heat exchanger (6) are connected by a plurality of fins (80) in common (see fig. 5 and 7).

Preferably, the arrangement structure is such that the 2 nd heat exchanger (2) is arranged above the 3 rd heat exchanger (6) (see fig. 4).

The outdoor unit 101 further includes a fan (70) for blowing air to the 2 nd heat exchanger (2) and the 3 rd heat exchanger (6), and the arrangement structure is as follows: the 2 nd heat exchanger (2) is disposed downstream of the 3 rd heat exchanger (6) with respect to the airflow generated by the fan (70) (see fig. 7 and 8).

The outdoor unit (101) further comprises a refrigerant amount adjustment mechanism (10), and the refrigerant amount adjustment mechanism (10) adjusts the circulation amount of the 1 st refrigerant in the defrosting mode.

Preferably, the refrigerant amount adjustment mechanism (10) includes: a liquid receiver (8) disposed between the 2 nd heat exchanger (2) and the 1 st expansion valve (3); refrigerant discharge pipes (34, 35) connected between the outlet of the liquid receiver (8) and the suction port of the 1 st compressor (1); and a flow rate adjustment valve (45) that adjusts the flow rate of the 1 st refrigerant flowing through the refrigerant discharge pipes (34, 35), wherein the outdoor unit (101) further comprises bypass flow paths (36, 37) in the defrosting mode, and the bypass flow paths (36, 37) allow the 1 st refrigerant to flow from the 1 st expansion valve (3) to the 2 nd heat exchanger (2) without passing through the liquid receiver (8).

The outdoor unit (101) further comprises: a 2 nd expansion valve (46) provided in the bypass flow paths (36, 37); and a check valve (43) that is provided in the bypass flow paths (36, 37) and that restricts the direction in which the refrigerant flows from the 2 nd expansion valve (46) to the 2 nd heat exchanger (2).

The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present disclosure is defined by the claims rather than the description of the above embodiments, and is intended to include meanings equivalent to the claims and all modifications within the scope.

Description of the reference numerals

1, a 1 st compressor; 2, a 2 nd heat exchanger; 3, expansion valve 1; 4, 1 st heat exchanger; 5 a 3 rd expansion valve; 6, a 3 rd heat exchanger; 9 a 2 nd compressor; 7, a four-way valve; 8 liquid receiver; 10 a refrigerant amount adjusting mechanism; 11 a cascade heat exchanger; 21 to 33, 38, 39, 47 to 49 pipes; 34 35 refrigerant discharge pipe; 36 37 bypass flow path; 41 to 43 check valves; 45 flow regulating valve; 46 a 2 nd expansion valve; 50 a control device; 51 a processor; 52 a memory; 61 a temperature sensor; 62 a pressure sensor; 70 70a,70b fans; 80 80a,80b fins; 100 a refrigeration device; 101 outdoor unit; 102 indoor units; 103 the 1 st refrigeration cycle device; 104 a 2 nd refrigeration cycle device; 260 to 262 integrated heat exchanger.

Claims

1. An outdoor unit of a refrigerating apparatus having a cooling mode and a defrosting mode,

the outdoor unit is provided with:

a 1 st refrigeration cycle device for circulating a 1 st refrigerant to an indoor unit, in which a 1 st expansion valve and a 1 st heat exchanger are connected in series;

a 2 nd refrigeration cycle device that circulates a 2 nd refrigerant; and

a cascade heat exchanger that performs heat exchange between the 1 st refrigerant and the 2 nd refrigerant,

the 1 st refrigeration cycle device includes:

1 st compressor and 2 nd heat exchanger; and

a four-way valve that switches between a connection destination of a discharge port of the 1 st compressor and a connection destination of a suction port of the 1 st compressor so that the 1 st refrigerant flows in a forward direction toward the 1 st expansion valve via the 1 st compressor and the 2 nd heat exchanger in the cooling mode and that the 1 st refrigerant flows in a reverse direction from the 1 st compressor toward the 1 st heat exchanger via the 2 nd heat exchanger in the defrosting mode,

the 2 nd refrigeration cycle device has a 2 nd compressor, a 3 rd expansion valve, and a 3 rd heat exchanger, circulates the 2 nd refrigerant in the order of the 2 nd compressor, the 3 rd heat exchanger, the 3 rd expansion valve, and the cascade heat exchanger,

the heat exchanger 2 is configured to absorb the exhaust heat of the heat exchanger 3.

2. The outdoor unit of claim 1,

the configuration structure is as follows: the pipe of the 2 nd heat exchanger through which the 1 st refrigerant flows and the pipe of the 3 rd heat exchanger through which the 2 nd refrigerant flows are connected by a plurality of fins in common.

3. The outdoor unit of claim 1 or 2,

the arrangement structure is such that the 2 nd heat exchanger is arranged above the 3 rd heat exchanger.

4. The outdoor unit of claim 1 or 2,

the outdoor unit further comprises a fan for blowing air to the 2 nd heat exchanger and the 3 rd heat exchanger,

the configuration structure is as follows: the 2 nd heat exchanger is disposed downstream of the 3 rd heat exchanger with respect to the airflow generated by the fan.

5. The outdoor unit of any one of claims 1 to 4,

the outdoor unit further includes a refrigerant amount adjusting mechanism that adjusts a circulation amount of the 1 st refrigerant in the defrosting mode.

6. The outdoor unit of claim 5,

the refrigerant amount adjustment mechanism includes:

a liquid receiver disposed between the 2 nd heat exchanger and the 1 st expansion valve;

a refrigerant discharge pipe connected between an outlet of the liquid receiver and a suction port of the 1 st compressor; and

a flow rate adjustment valve that adjusts a flow rate of the 1 st refrigerant flowing through the refrigerant discharge pipe,

the outdoor unit further includes a bypass flow path for allowing the 1 st refrigerant to flow from the 1 st expansion valve to the 2 nd heat exchanger without passing through the liquid receiver in the defrosting mode.

7. The outdoor unit of claim 6,

the outdoor unit further includes:

a 2 nd expansion valve provided in the bypass flow path; and

and a check valve provided in the bypass flow path and configured to restrict a refrigerant flow direction to a direction in which the refrigerant flows from the 2 nd expansion valve to the 2 nd heat exchanger.

8. A refrigerating apparatus, wherein,

the refrigeration device is provided with:

the outdoor unit of any one of claims 1 to 7; and

the indoor unit.