EP4354050A1

EP4354050A1 - Refrigeration device

Info

Publication number: EP4354050A1
Application number: EP21944968.3A
Authority: EP
Inventors: Ryo TSUKIYAMA
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2021-06-07
Filing date: 2021-06-07
Publication date: 2024-04-17
Also published as: CN117321358A; WO2022259287A1; JPWO2022259287A1

Abstract

A refrigeration apparatus includes: a main circuit serving as a refrigerant circuit in which a compressor, a condenser, a receiver, a first open-close valve, an expansion mechanism, an evaporator, and an accumulator are sequentially connected by refrigerant pipes, and in which refrigerant is circulated; an evaporation mechanism configured to evaporate, after a precooling operation is performed to cool the evaporator, liquid refrigerant stored in the accumulator, or configured to evaporate, during the precooling operation which is performed to cool the evaporator, liquid refrigerant that flows through one of the refrigerant pipes that is located on a suction side of the accumulator; and a controller configured to control the main circuit and the evaporation mechanism.

Description

Technical Field

The present disclosure relates to a refrigeration apparatus.

Background Art

In the past, a refrigeration apparatus has been known that includes a refrigerant circuit in which a compressor, a condenser, a receiver, an expansion valve, an evaporator, and an accumulator are sequentially connected by refrigerant pipes, and in which refrigerant is circulated, as disclosed in, for example, Patent Literature 1. The refrigeration apparatus disclosed in Patent Literature 1 includes a bypass circuit that branches off from a refrigerant pipe located between the compressor and the condenser and that is connected to a refrigerant pipe located between the expansion valve and the evaporator. In the bypass circuit, a solenoid valve is provided. Furthermore, this refrigeration apparatus is provided with a temperature sensor that detects the temperature of the evaporator or the temperature of refrigerant discharged from the evaporator.
In the above refrigeration apparatus, at the time of performing a defrosting operation, a controller stops an air-sending device for the evaporator and an air-sending device for the condenser, and opens the solenoid valve. Then, high-temperature and high-pressure refrigerant discharged from the compressor flows through the bypass circuit and is supplied to the evaporator. The controller controls a refrigerant discharge capacity of the compressor to cause the gradient of a rise in the temperature detected by the temperature sensor be closer to the gradient of a target rise in the temperature. Thus, it is possible to give a heat quantity of hot gas that varies depending on a change in the amount of frost that forms on the evaporator. When the defrosting operation ends, the air-sending device for the condenser is operated, with the air-sending device for the evaporator kept in the stopped state, the solenoid valve is closed, and a precooling operation for the evaporator is started. The precooling operation is performed to cool the evaporator the temperature of which is raised to a high temperature by the defrosting operation.
When the temperature detected by the temperature sensor reaches a target temperature after the precooling operation for the evaporator is started, the precooling operation for the evaporator is ended. When the temperature detected by the temperature sensor does not reach the target temperature, it is determined whether a target time period elapses from the start of the precooling operation or not, and when the target time period elapses, the precooling operation for the evaporator is ended. When the target time period does not elapse, it is re-determined whether the temperature detected by the temperature sensor reaches the target temperature or not.

Citation List

Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2017-166730

Summary of Invention

Technical Problem

By controlling the refrigerant discharge capacity of the compressor based on a value detected by the temperature sensor, the refrigeration apparatus of Patent Literature 1 can reduce the rise in the temperature of the evaporator in the defrosting operation and shorten the operating time for which the precooling operation is performed. However, in the precooling operation, since the air-sending device for the evaporator is in the stopped state, the amount of heat exchange at the evaporator exchange is small, and liquid refrigerant that does not evaporate in the evaporator flows into the accumulator. After that, when the precooling operation is ended and the cooling operation is stated, it takes long time to drain a large amount of liquid refrigerant stored in the accumulator. As a result, the amount of refrigerant that circulates in the refrigerant circuit may fall short and the refrigeration capacity may thus be deteriorated.
The present disclosure is applied to solve the above problem and relates to a refrigeration apparatus that can promote, at the time of ending a precooling operation and starting a cooling operation, drainage of liquid from an accumulator and reduce deterioration of a refrigeration capacity.

Solution to Problem

A refrigeration apparatus according to an embodiment of the present disclosure includes a main circuit serving as a refrigerant circuit in which a compressor, a condenser, a receiver, a first open-close valve, an expansion mechanism, an evaporator, and an accumulator are sequentially connected by refrigerant pipes, and in which refrigerant is circulated; an evaporation mechanism configured to evaporate, after a precooling operation is performed to cool the evaporator, liquid refrigerant stored in the accumulator, or configured to evaporate, during the precooling operation which is performed to cool the evaporator, liquid refrigerant that flows through one of the refrigerant pipes that is located on a suction side of the accumulator; and a controller configured to control the main circuit and the evaporation mechanism.

Advantageous Effects of Invention

In the refrigeration apparatus according to the embodiment of the present disclosure, after the precooling operation, the liquid refrigerant stored in the accumulator is evaporated by the evaporation mechanism, or during the precooling operation, the liquid refrigerant that flows through the refrigerant pipe located on the suction side of the accumulator is evaporated by the evaporation mechanism. Thus, when the precooling operation is ended and the cooling operation is started, it is possible to promote drainage of liquid from the accumulator and reduce deterioration of the refrigeration capacity.

Brief Description of Drawings

[Fig. 1] Fig. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 1.
[Fig. 2] Fig. 2 is a flow chart of operation modes of the refrigeration apparatus according to Embodiment 1.
[Fig. 3] Fig. 3 is a flow chart of a cooling operation mode of the refrigeration apparatus according to Embodiment 1.
[Fig. 4] Fig. 4 is a flow chart of a defrosting operation mode of the refrigeration apparatus according to Embodiment 1.
[Fig. 5] Fig. 5 is a flow chart of a precooling operation mode of the refrigeration apparatus according to Embodiment 1.
[Fig. 6] Fig. 6 is a flow chart of a draining operation mode of the refrigeration apparatus according to Embodiment 1.
[Fig. 7] Fig. 7 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 2.
[Fig. 8] Fig. 8 is a flow chart of a draining operation mode of the refrigeration apparatus according to Embodiment 2.
[Fig. 9] Fig. 9 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 3.
[Fig. 10] Fig. 10 is a flow chart of a draining operation mode of the refrigeration apparatus according to Embodiment 3.
[Fig. 11] Fig. 11 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 4.
[Fig. 12] Fig. 12 is a flow chart of a draining operation mode of the refrigeration apparatus according to Embodiment 4.
[Fig. 13] Fig. 13 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 5.
[Fig. 14] Fig. 14 is a flow chart of operation modes of the refrigeration apparatus according to Embodiment 5.
[Fig. 15] Fig. 15 is a flow chart of a precooling operation mode of the refrigeration apparatus according to Embodiment 5.
[Fig. 16] Fig. 16 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 6.
[Fig. 17] Fig. 17 is a flow chart of a precooling operation mode of the refrigeration apparatus according to Embodiment 6.
[Fig. 18] Fig. 18 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 7.
[Fig. 19] Fig. 19 is a flow chart of a precooling operation mode of the refrigeration apparatus according to Embodiment 7.

Description of Embodiments

The embodiments of the present disclosure will be described with reference to the drawings. In each of figures in the drawings, components that are the same as or equivalent to those in a previous figure or previous figures are denoted by the same reference signs, and their descriptions will thus be omitted or simplified as appropriate. Furthermore, the components as illustrated in each figure can be changed as appropriate in shape, size, position, etc.

Embodiment 1

First, a refrigeration apparatus 101 according to Embodiment 1 will be described with reference to Figs. 1 to 6. Fig. 1 is a refrigerant circuit diagram of the refrigeration apparatus 101 according to Embodiment 1. As illustrated in Fig. 1, the refrigeration apparatus 101 according to Embodiment 1 includes a main circuit 1, an evaporation mechanism 2, and a controller 3. The main circuit 1 is a refrigerant circuit in which a compressor 10, a condenser 11, a receiver 12, a first open-close valve 13, an expansion mechanism 14, an evaporator 15, and an accumulator 16 are sequentially connected by refrigerant pipes 17, and in which refrigerant is circulated. The compressor 10, the condenser 11, the receiver 12, and the accumulator 16 are provided in an outdoor unit 200. The first open-close valve 13, the expansion mechanism 14, and the evaporator 15 are provided in an indoor unit 300. The evaporation mechanism 2 is configured to evaporate liquid refrigerant 16a that is stored in the accumulator 16. The controller 3 is configured to control the main circuit 1 and the evaporation mechanism 2.
The compressor 10 is configured to suck refrigerant, compress the refrigerant to change it into high-temperature and high-pressure refrigerant, and discharge the high-temperature and high-pressure refrigerant. The compressor 10 is, for example, an inverter compressor. The refrigerant discharged from the compressor 10 flows into the condenser 11.
The condenser 11 causes heat exchange to be performed between air and the refrigerant discharged from the compressor 10. The condenser 11 sucks outdoor air through a condenser fan 11a, and lets out air subjected to heat exchange with the refrigerant to the outside.
The receiver 12 is a refrigerant container in which liquid refrigerant is stored, stores surplus liquid refrigerant that remains during operation, and has a gas-liquid phase separation function.
The first open-close valve 13 is a movable mechanism that can open/close a passage in a refrigerant pipe 17 to allow/stop the flow of refrigerant. The first open-close valve 13 is, for example, a solenoid valve, and is controlled by the controller 3.
The expansion mechanism 14 is configured to decompress and expand refrigerant that flows in the main circuit 1. As the expansion mechanism 14, an expansion valve or a capillary tube can be used. In this case, the expansion mechanism 14 is an electronic expansion valve whose opening degree is variably controlled.
The evaporator 15 causes heat exchange to be performed between air and refrigerant that flows out from the expansion mechanism 14. Furthermore, the evaporator 15 sucks indoor air through an evaporator fan 15a, and supplies air subjected to heat exchange with the refrigerant into an indoor space. Furthermore, the evaporator 15 is provided with a heating unit 15b that heats frost forming on the evaporator 15 in the defrosting operation to remove the frost from the evaporator 15. An example of the heating unit 15b is a heater. Furthermore, the evaporator 15 is provided with a temperature sensor (not illustrated) that detects the temperature of refrigerant that flows through the evaporator 15.
The accumulator 16 is located upstream of a suction port of the compressor 10. The accumulator 16 separates two-phase gas-liquid refrigerant that flows out from the evaporator 15 into gas refrigerant and liquid refrigerant 16a, and then stores the liquid refrigerant 16a in a lower space in a container.
The evaporation mechanism 2 is configured to evaporate the liquid refrigerant 16a stored in the accumulator 16, after a precooling operation. As illustrated in Fig. 1, the evaporation mechanism 2 includes a first bypass circuit 20, a second bypass circuit 21, flow switching valves 22, and a second open-close valve 23.
The first bypass circuit 20 has an inlet portion 20a that branches off from a refrigerant pipe 17 located between the condenser 11 and the receiver 12 and an outlet portion 20b that is connected to a refrigerant pipe 17 located between the receiver 12 and the first open-close valve 13, and forms part of the refrigerant circuit. The second bypass circuit 21 connects upper part of the receiver 12 and lower part of the accumulator 16. In the upper part of the receiver 12, the gas refrigerant stays. In the lower part of the accumulator 16, the liquid refrigerant 16a is stored.
The flow switching valves 22 are, for example, three-way valves, and are controlled by the controller 3. The flow switching valves 22 are provided at the inlet portion 20a and the outlet portion 20b of the first bypass circuit 20. The flow switching valves 22 each switch a flow passage to be used, between a flow passage for refrigerant that flows through the receiver 12 and a flow passage for refrigerant that flows through the first bypass circuit 20. Furthermore, the second open-close valve 23 is, for example, a solenoid valve, and is controlled by the controller 3. The second open-close valve 23 is provided in the second bypass circuit 21.
The controller 3 includes an arithmetic device such as a microcomputer or a CPU and software that is run on the arithmetic device. It should be noted that the controller 3 may be hardware such as a circuit device that fulfills functions of the controller 3. The controller 3 causes each of the flow switching valves 22 to perform a switching operation thereof, to cause the refrigerant to flow in the first bypass circuit 20, and also opens the second open-close valve 23 to cause liquid refrigerant in the receiver 12 to flow into the accumulator 16 to evaporate the liquid refrigerant 16a stored in the accumulator 16.
Next, operation modes of the refrigeration apparatus 101 according to Embodiment 1 will be described with reference to Fig. 2. Fig. 2 is a flow chart of the operation modes of the refrigeration apparatus 101 according to Embodiment 1. As illustrated in Fig. 2, as the operation modes of the refrigeration apparatus 101 according to Embodiment 1, a cooling operation mode S1, a defrosting operation mode S2, a precooling operation mode S3, and a draining operation mode S4 are applied in this order. After the draining operation mode S4 ends, the cooling operation mode S1 is reapplied.
First of all, the cooling operation mode S1 of the refrigeration apparatus 101 according to Embodiment 1 will be described with reference to Fig. 3. Fig. 3 is a flow chart of the cooling operation mode S1 of the refrigeration apparatus 101 according to Embodiment 1. In the cooling operation mode S1, for example, the inside of a vast warehouse that is a cooling target is cooled. In the warehouse, for example, frozen food and fresh food are preserved. The cooling target is not limited to the warehouse.
First, after a cooling operation starts, in step S101, the controller 3 sets the mode of the refrigerant circuit to the cooling operation mode S1. In the setting of the refrigerant circuit, the flow switching valves 22 are switched to cause the refrigerant to flow to the receiver 12, and the second open-close valve 23 is closed. That is, in step S101, the refrigerant circuit is set such that the refrigerant flows only in the main circuit 1. Then, in step S102, the controller 3 opens the first open-close valve 13 and turns on the evaporator fan 15a. As a result, the temperature of refrigerant that flows through the evaporator 15 rises.
Next, in step S103, the controller 3 determines whether or not the relationship between an evaporating temperature Te that is the temperature of refrigerant in the evaporator 15 and a target value Te_set of the evaporating temperature Te satisfies Te > Te_set. When Te > Te_set is satisfied, the processing by the controller 3 proceeds to step S104, in which the controller 3 turns on the condenser fan 11a and turns on the compressor 10. By contrast, when Te > Te_set is not satisfied the controller 3 repeatedly carries out step S103 until Te > Te_set is satisfied.
Next, in step S105, the controller 3 determines whether a defrosting condition is satisfied or not. The defrosting condition is, for example, whether it is past a predetermined target time or not, or whether each of predetermined intervals elapses or not. Alternatively, it may be determined by a user's selection whether the defrosting condition is satisfied or not. In step S105, when the defrosting condition is satisfied, the controller 3 ends the cooling operation. By contrast, in step S105, when the defrosting condition is not satisfied, the processing by the controller 3 proceeds to step S106.
Next, in step S106, the controller 3 determines whether the relationship between an inside temperature Ta that is a temperature in the warehouse that is the cooling target and a target value Ta_set of the inside temperature Ta is Ta < Ta_set or not. When Ta < Ta_set is satisfied, the processing by the controller 3 proceeds to step S107, in which the controller 3 closes the first open-close valve 13 and turns off the evaporator fan 15a. By contrast, in step S106, when Ta < Ta_set is not satisfied, the controller 3 repeatedly carries out step S106 until Ta < Ta_set is satisfied.
Next, in step S108, the controller 3 determines whether the relationship between the evaporating temperature Te and the target value Te_set of the evaporating temperature Te satisfies Te < Te_set or not. When Te < Te_set is satisfied, the processing by the controller 3 proceeds to step S109, in which the controller 3 turns off the condenser fan 11a and turns off the compressor 10. By contrast, in step S108, when Te < Te_set is not satisfied, the controller 3 repeatedly carries out step S108 until Te < Te_set is satisfied.
Next, in step S110, the controller 3 determines whether the relationship between the inside temperature Ta and the target value Ta_set of the inside temperature Ta is Ta > Ta_set or not. When Ta > Ta_set is satisfied, the processing by the controller 3 returns to step S102, in which the controller 3 re-opens the first open-close valve 13 and re-turns on the evaporator fan 15a. By contrast, in step S110, when Ta > Ta_set is not satisfied, the controller 3 repeatedly carries out step S110 until Ta > Ta_set is satisfied.
Next, the defrosting operation mode S2 of the refrigeration apparatus 101 according to Embodiment 1 will be described with reference to Fig. 4. Fig. 4 is a flow chart of the defrosting operation mode S2 of the refrigeration apparatus 101 according to Embodiment 1. The defrosting operation mode S2 is applied to remove frost forming on the evaporator 15.
The controller 3 starts the defrosting operation, after the cooling operation ends based on the determination that the defrosting condition is satisfied in step S105 indicated in Fig. 3. First, as indicated in Fig. 4, after the start of the defrosting operation, in step S111, the controller 3 closes the first open-close valve 13, turns off the evaporator fan 15a, and turns on the heater, which is the heating unit 15b.
Next, in step S112, the controller 3 determines whether the relationship between the evaporating temperature Te that is the temperature of refrigerant in the evaporator 15 and the target value Te_set of the evaporating temperature Te satisfies Te < Te_set or not. When Te < Te_set is satisfied, the processing by the controller 3 proceeds to step S113, in which the controller 3 turns off the condenser fan 11a and turns off the compressor 10. By contrast, in step S112, when Te < Te_set is not satisfied, the controller 3 repeatedly carries out step S112 until Te < Te_set is satisfied.
Next, in step S114, the controller 3 determines whether a defrosting ending condition is satisfied or not. The defrosting ending condition is, for example, whether a predetermined target time period elapses or not, or whether the temperature of an outlet pipe of the evaporator 15 reaches a predetermined temperature or not. In step S114, when the defrosting ending condition is satisfied, the processing by the controller 3 proceeds to step S115, in which the controller 3 turns off the heater, which is the heating unit 15b. Then, the controller 3 ends the defrosting operation. By contrast, in step S114, when the defrosting ending condition is not satisfied, the controller 3 repeatedly carries out step S114 until the defrosting ending condition is satisfied.
Next, the precooling operation mode S3 of the refrigeration apparatus 101 according to Embodiment 1 will be described with reference to Fig. 5. Fig. 5 is a flow chart of the precooling operation mode S3 of the refrigeration apparatus 101 according to Embodiment 1. The precooling operation mode S3 is applied to prevent the heat of the evaporator 15 from being transferred into the warehouse by the evaporator fan 15a, when the temperature of the evaporator 15 is raised to a high temperature by the defrosting operation. In the precooling operation mode S3, the refrigerant is circulated in the main circuit 1, with the evaporator fan 15a being in the stopped state, whereby the evaporator 15 is cooled before the cooling operation.
The controller 3 starts the precooling operation after ending the defrosting operation indicated in Fig. 4. First, as indicated in Fig. 5, after the precooling operation starts, in step S116, the controller 3 sets the mode of the refrigerant circuit to the precooling operation mode S3. In the setting of the refrigerant circuit, the flow switching valves 22 are switched to cause the refrigerant to flow to the first bypass circuit 20. That is, in the precooling operation, refrigerant that flows out from the condenser 11 is made to flow into the first bypass circuit 20, whereby the refrigerant circuit is set in such a manner as to bypass the receiver 12. At this time, the second open-close valve 23 is kept in the closed state. In addition, the condenser fan 11a and the evaporator fan 15a are kept in the off-state. Then, in step S117, the controller 3 opens the first open-close valve 13. As a result, the temperature of refrigerant that flows through the evaporator 15 rises.
Next, in step S118, the controller 3 determines whether the relationship between the evaporating temperature Te, which is the temperature of refrigerant in the evaporator 15, and the target value Te_set of the evaporating temperature Te satisfies Te > Te_set or not. When Te > Te_set is satisfied, the processing by the controller 3 proceeds to step S119, in which the controller 3 turns on the condenser fan 11a and turns on the compressor 10. By contrast, in step S118, when Te > Te_set is not satisfied, the controller 3 repeatedly carries out step S118 until Te > Te_set is satisfied.
Next, in step S120, the controller 3 determines whether a precooling ending condition is satisfied or not. The precooling ending condition is, for example, whether a predetermined target time period elapses or not, or whether the temperature of the outlet pipe of the evaporator 15 reaches a predetermined temperature or not. In step S120, when the precooling ending condition is satisfied, the processing by the controller 3 proceeds to step S121, in which the controller 3 turns on the evaporator fan 15a. Then, the controller 3 ends the precooling operation. By contrast, in step S120, when the precooling ending condition is not satisfied, the controller 3 repeatedly carries out step S120 until the precooling ending condition is satisfied.
Next, the draining operation mode S4 of the refrigeration apparatus 101 according to Embodiment 1 will be described with reference to Fig. 6. Fig. 6 is a flow chart of the draining operation mode S4 of the refrigeration apparatus 101 according to Embodiment 1. The controller 3 starts a draining operation after ending the precooling operation as indicated in Fig. 5. First, after the draining operation starts, in step S201, the controller 3 opens the second open-close valve 23 of the second bypass circuit 21, as indicated in Fig. 6. Then, the liquid refrigerant in the receiver 12 flows into the accumulator 16 to evaporate the liquid refrigerant 16a stored in the accumulator 16. At this time, the flow switching valves 22 are in a state in which the flow switching valves 22 are set at the time of performing the precooling operation, and are in their switched state to cause the refrigerant to flow to the first bypass circuit 20.
Next, in step S202, the controller 3 determines whether a draining ending condition is satisfied or not. The draining ending condition is, for example, whether a predetermined target time period elapses or not, whether the temperature in the accumulator 16 reaches a target temperature or not, or whether the temperature of a suction pipe of the compressor 10 reaches a target temperature or not. When the draining ending condition is satisfied, the processing by the controller 3 proceeds to step S203, in which the controller 3 closes the second open-close valve 23 of the second bypass circuit 21. Then, the controller 3 ends the draining operation. By contrast, in step S202, when the draining ending condition is not satisfied, the controller 3 repeatedly carries out step S202 until the draining ending condition is satisfied.
As described above, the refrigeration apparatus 101 according to Embodiment 1 includes: the main circuit 1 which serves as the refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by the refrigerant pipes 17 and in which the refrigerant is circulated; the evaporation mechanism 2 configured to evaporate the liquid refrigerant 16a stored in the accumulator 16, after the precooling operation is performed to cool the evaporator 15; and a controller 3 configured to control the main circuit 1 and the evaporation mechanism 2.
The evaporation mechanism 2 includes the first bypass circuit 20 which has the inlet portion 20a branching off the refrigerant pipe 17 located between the condenser 11 and the receiver 12, which has the outlet portion 20b connected to the refrigerant pipe 17 located between the receiver 12 and the first open-close valve 13, and which forms part of the refrigerant circuit. Furthermore, the evaporation mechanism 2 includes the second bypass circuit 21 which connects the receiver 12 and the accumulator 16 and which forms part of the refrigerant circuit. In addition, the evaporation mechanism 2 includes the flow switching valves 22 provided at the inlet portion 20a and the outlet portion 20b and configured to switch the flow passage between the flow passage for refrigerant that flows in the main circuit 1 and the flow passage for refrigerant that flows through the first bypass circuit 20; and the second open-close valve 23 provided in the second bypass circuit 21. The controller 3 switches the flow switching valves 22 to cause the refrigerant to flow to the first bypass circuit 20, and also opens the second open-close valve 23 to cause liquid refrigerant in the receiver 12 to flow into the accumulator 16 to evaporate the liquid refrigerant 16a stored in the accumulator 16.
Therefore, in the refrigeration apparatus 101 according to Embodiment 1, after the precooling operation, the liquid refrigerant 16a stored in the accumulator 16 can be evaporated by the evaporation mechanism 2, whereby it is possible to promote drainage of liquid from the accumulator 16 and reduce deterioration of the refrigeration capacity, when the precooling operation is ended and the cooling operation is started.

Embodiment 2

Next, the following description concerning a refrigeration apparatus 102 according to Embodiment 2 is made with reference to Figs. 7 and 8 by also referring to Figs. 2 to 5. Fig. 7 is a refrigerant circuit diagram of the refrigeration apparatus 102 according to Embodiment 2. Fig. 8 is a flow chart of the draining operation mode S4 of the refrigeration apparatus 102 according to Embodiment 2. It should be noted that regarding Embodiment 2, components that are the same as those in Embodiment 1 will be denoted by the same reference sings, and their descriptions will thus be omitted as appropriate.
As illustrated in Fig. 7, the refrigeration apparatus 102 according to Embodiment 2 includes the main circuit 1, the evaporation mechanism 2, and the controller 3. The main circuit 1 serves as a refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by the refrigerant pipes 17 and in which the refrigerant is circulated. The compressor 10, the condenser 11, the receiver 12, and the accumulator 16 are provided in the outdoor unit 200. The first open-close valve 13, the expansion mechanism 14, and the evaporator 15 are provided in the indoor unit 300. The evaporation mechanism 2 is configured to evaporate liquid refrigerant 16a stored in the accumulator 16. The controller 3 is configured to control the main circuit 1 and the evaporation mechanism 2. The compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 have the same configurations as those in Embodiment 1 which are described above.
The evaporation mechanism 2 evaporates the liquid refrigerant 16a stored in the accumulator 16, after the precooling operation. As illustrated in Fig. 7, the evaporation mechanism 2 includes the first bypass circuit 20, the second open-close valve 23, and a third open-close valve 24.
The first bypass circuit 20 has the inlet portion 20a which branches off from a refrigerant pipe 17 of the main circuit 1 that is located between the compressor 10 and the condenser 11, allows passage of the liquid refrigerant 16a stored in the accumulator 16, has an outlet portion 20b connected with a refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the condenser 11, and forms part of the refrigerant circuit.
The second open-close valve 23 is provided at a refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the outlet portion 20b of the first bypass circuit 20. The second open-close valve 23 is, for example, a solenoid valve, and is controlled by the controller 3.
The third open-close valve 24 is provided in part of the first bypass circuit 20 that is located between the inlet portion 20a and the accumulator 16. The third open-close valve 24 is, for example, a solenoid valve, and is controlled by the controller 3.
The controller 3 of the refrigeration apparatus 102 according to Embodiment 2 closes he second open-close valve 23 and opens the third open-close valve 24 to cause high-temperature and high-pressure gas refrigerant discharged from the compressor 10 to flow in the first bypass circuit 20 to evaporate the liquid refrigerant 16a stored in the accumulator 16.
Next, operation modes of the refrigeration apparatus 102 according to Embodiment 2 will be described. As illustrated in Fig. 2, in the refrigeration apparatus 102 according to Embodiment 2, the cooling operation mode S1, the defrosting operation mode S2, the precooling operation mode S3, and the draining operation mode S4 are applied in this order as in the refrigeration apparatus 101 of Embodiment 1. After the draining operation mode S4 ends, the cooling operation mode S1 is re-started.
In the cooling operation mode S1 of the refrigeration apparatus 102 according to Embodiment 2, steps are carried out as indicated in Fig. 3. More specifically, first, after the refrigerant operation starts, in step S1001, the controller 3 sets the mode of the refrigerant circuit to the cooling operation mode S1. In the setting of the refrigerant circuit, the second open-close valve 23 is opened and the third open-close valve 24 is closed. That is, in step S101, the refrigerant circuit is set to cause the refrigerant to flows only in the main circuit 1.
Steps S102 to S110 are the same as those in Embodiment 1 which are described above, and their detailed descriptions will thus be omitted.
Next, in the defrosting operation mode S2 of the refrigeration apparatus 102 according to Embodiment 2, steps are carried out as indicated in Fig. 4. The defrosting operation mode S2 is the same as that in Embodiment 1 which is described above, and its detailed description of the defrosting operation mode S2 will thus be omitted.
In the precooling operation mode S3 of the refrigeration apparatus 102 according to Embodiment 2, steps are carried out as indicated in Fig. 5. The controller 3 starts the precooling operation after the defrosting operation indicated in Fig. 4 ends. First, as indicated in Fig. 5, after the precooling operation starts, in step S116, the controller 3 sets the mode of the refrigerant circuit to the precooling operation mode S3. In the setting of the refrigerant circuit, the second open-close valve 23 is opened and the third open-close valve 24 is closed. It should be noted that the setting of the refrigerant circuit in step S116 may be omitted, since the refrigerant circuit is set in step S101.
Steps S117 to S121 are the same as those in Embodiment 1, and their detailed descriptions will thus be omitted.
Next, the draining operation mode S4 of the refrigeration apparatus 102 according to Embodiment 2 will be described with reference to Fig. 8. The controller 3 starts the draining operation after ending the precooling operation as indicated in Fig. 5. First, as indicated in Fig. 8, after the draining operation ends, in step S301, the controller 3 closes the second open-close valve 23 and opens the third open-close valve 24. Then, the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows into the first bypass circuit 20 to evaporate the liquid refrigerant 16a stored in the accumulator 16. Gas refrigerant produced by evaporation of the liquid refrigerant 16a is sucked into the compressor 10.
Next, in step S302, the controller 3 determines whether a draining ending condition is satisfied. The draining ending condition is, for example, whether a predetermined target time period elapses or not, whether the temperature in the accumulator 16 reaches a target temperature, or whether the temperature of the suction pipe of the compressor 10 reaches a target temperature. When the draining ending condition is satisfied, the processing by the controller 3 proceeds to step S303, in which the controller 3 opens the second open-close valve 23 and closes the third open-close valve 24 to cause the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 to flow in the main circuit 1. Then, the controller 3 ends the draining operation. By contrast, in step S303, when the draining ending condition is not satisfied, the controller 3 repeatedly carries out step S303 until the draining ending condition is satisfied.
As described above, the evaporation mechanism 2 of the refrigeration apparatus 102 according to Embodiment 2 includes the first bypass circuit 20 which has the inlet portion 20a branching off from the refrigerant pipe 17 of the main circuit 1 that is located between the compressor 10 and the condenser 11, which allows passage of the liquid refrigerant 16a stored in the accumulator 16, which has the outlet portion 20b connected to the refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the condenser 11, and which forms part of the refrigerant circuit. Furthermore, the evaporation mechanism 2 includes the second open-close valve 23 provided at the refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the outlet portion 20b, and the third open-close valve 24 provided in part of the first bypass circuit 20 that is located between the inlet portion 20a and the accumulator 16. The controller 3 closes the second open-close valve 23 and opens the third open-close valve 24 to cause gas refrigerant discharged from the compressor 10 to flow into the first bypass circuit 20 to evaporate the liquid refrigerant 16a stored in the accumulator 16.
Therefore, in the refrigeration apparatus 102 according to Embodiment 2, after the precooling operation, the liquid refrigerant 16a stored in the accumulator 16 can be evaporated by the evaporation mechanism 2, whereby it is possible to promote drainage of liquid from the accumulator 16 and reduce deterioration of refrigeration capacity, when the precooling operation is ended and the cooling operation is started.

Embodiment 3

Next, the following description concerning a refrigeration apparatus 103 according to Embodiment 3 is made with reference to Figs. 9 and 10 by also referring to Figs. 2 to 5. Fig. 9 is a refrigerant circuit diagram of the refrigeration apparatus 103 according to Embodiment 3. Fig. 10 is a flow chart of the draining operation mode S4 of the refrigeration apparatus 103 according to Embodiment 3. It should be noted that Regarding Embodiment 3, components that are the same as those in Embodiment 1 will be denoted by the same reference signs, and their descriptions will thus be omitted as appropriate.
As illustrated in Fig. 9, the refrigeration apparatus 103 according to Embodiment 3 includes the main circuit 1, the evaporation mechanism 2, and the controller 3. The main circuit 1 serves as a refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by the refrigerant pipes 17 and in which the refrigerant is circulated. The compressor 10, the condenser 11, the receiver 12, and the accumulator 16 are provided in the outdoor unit 200. The first open-close valve 13, the expansion mechanism 14, and the evaporator 15 are provided in the indoor unit 300. The evaporation mechanism 2 is configured to evaporate the liquid refrigerant 16a stored in the accumulator 16. The controller 3 is configured to control the main circuit 1 and the evaporation mechanism 2. The compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 have the same configurations as those in Embodiment 1 which are described above.
The evaporation mechanism 2 evaporates the liquid refrigerant 16a stored in the accumulator 16, after the precooling operation. As illustrated in Fig. 9, the evaporation mechanism 2 includes the first bypass circuit 20, the second bypass circuit 21, the expansion valve 25, an internal heat exchanger 26, the second open-close valve 23, and the third open-close valve 24.
The first bypass circuit 20 has the first inlet portion 20a branching off from a refrigerant pipe 17 that is located between the receiver 12 and the first open-close valve 13, has the first outlet portion 20b connected to the compressor 10, and forms part of the refrigerant circuit.
The second bypass circuit 21 has a second inlet portion 21a branching off from the first bypass circuit 20, allows passage of the liquid refrigerant 16a stored in the accumulator 16, has a second outlet portion 21b connected to part of the first bypass circuit 20 that is located between the second inlet portion 21a and the compressor 10, and forms part of the refrigerant circuit.
The expansion valve 25 is provided in part of the first bypass circuit 20 that is located between the first inlet portion 20a of the first bypass circuit 20 and the second inlet portion 21a of the second bypass circuit 21. The expansion valve 25 is configured to decompress and expand liquid refrigerant that flows into the first bypass circuit 20 via the first inlet portion 20a. The expansion valve 25 is, for example, an electronic expansion valve whose opening degree is variably controlled.
The internal heat exchanger 26 is configured to cause heat exchange to be performed between high-pressure refrigerant that flows in part of the main circuit 1 that is located between the receiver 12 and the first inlet portion 20a and intermediate-pressure refrigerant that flows in part of the first bypass circuit 20 that is located between the expansion valve 25 and the second inlet portion 21a.
The second open-close valve 23 is provided in part of the first bypass circuit 20 that is located between the second inlet portion 21a and the second outlet portion 21b. The second open-close valve 23 is, for example, a solenoid valve, and is controlled by the controller 3.
The third open-close valve 24 is provided in part of the second bypass circuit 21 that is located between the second inlet portion 21a and the accumulator 16. The third open-close valve 24 is, for example, a solenoid valve, and is controlled by the controller 3.
The controller 3 of the refrigeration apparatus 103 according to Embodiment 3 closes the second open-close valve 23 and opens the third open-close valve 24 to cause liquid refrigerant that flows into the first bypass circuit 20 and is decompressed by the expansion valve 25 to exchange heat, in the internal heat exchanger 26, with liquid refrigerant that flows out from the condenser 11, and then causes the liquid refrigerant to flow into the second bypass circuit 21 to evaporate the liquid refrigerant 16a stored in the accumulator 16.
Next, operation modes of the refrigeration apparatus 103 according to Embodiment 3 will be described. As illustrated in Fig. 2, in the refrigeration apparatus 103 according to Embodiment 3, the cooling operation mode S1, the defrosting operation mode S2, the precooling operation mode S3, and the draining operation mode S4 are applied in this order as in the refrigeration apparatus 101 of Embodiment 1. After the draining operation mode S4 ends, the cooling operation mode S1 is re-started.
In the cooling operation mode S1 of the refrigeration apparatus 103 according to Embodiment 3, steps are carried out as indicated in Fig. 3. First, after the refrigerant operation starts, in step S101, the controller 3 sets the mode of the refrigerant circuit to the cooling operation mode S1. In the setting of the refrigerant circuit, the second open-close valve 23 is opened and the third open-close valve 24 is closed. That is, in step S101, the refrigerant circuit is set to cause the refrigerant to flow in the main circuit 1 and the first bypass circuit 20.
Steps S102 to S110 are the same as those in Embodiment 1 which are described above, and their detailed descriptions will thus be omitted.
Next, in the defrosting operation mode S2 of the refrigeration apparatus 103 according to Embodiment 3, steps are carried out as indicated in Fig. 4. The defrosting operation mode S2 is the same as that in Embodiment 1 which is described above, and its detailed description will thus be omitted.
In the precooling operation mode S3 of the refrigeration apparatus 103 according to Embodiment 3, steps are carried out as indicated in Fig. 5. The controller 3 starts the precooling operation after ending the defrosting operation as indicated in Fig. 4. First, as indicated in Fig. 5, after the precooling operation starts, in step S116, the controller 3 sets the mode of the refrigerant circuit to the precooling operation mode S3. The refrigerant circuit is set to open the second open-close valve 23 and close the third open-close valve 24. It should be noted that the setting of the refrigerant circuit in step S116 may be omitted, as it is the same as the setting of the refrigerant circuit in step S101.
Steps S117 to S121 are the same as those in Embodiment 1 which are described above, and their detailed descriptions will thus be omitted.
Next, the draining operation mode S4 of the refrigeration apparatus 103 according to Embodiment 3 will be described with reference to Fig. 10. The controller 3 starts the draining operation after ending the precooling operation as indicated in Fig. 5. First, as indicated in Fig. 10, after the draining operation starts, in step S401, the controller 3 closes the second open-close valve 23 and opens the third open-close valve 24. Then, liquid refrigerant that flows into the first bypass circuit 20 and is decompressed by the expansion valve 25 exchanges heat, in the internal heat exchanger 26, with liquid refrigerant that flows therein from the condenser 11, and then flows into the second bypass circuit 21 via the second inlet portion 21a to evaporate the liquid refrigerant 16a stored in the accumulator 16. Gas refrigerant produced by evaporation of the liquid refrigerant 16a is sucked into the compressor 10.
Next, in step S402, the controller 3 determines whether a draining ending condition is satisfied or not. The draining ending condition is, for example, whether a predetermined target time period elapses or not, whether the temperature in the accumulator 16 reaches a target temperature or not, or whether the temperature of the suction pipe of the compressor 10 reaches a target temperature or not. When the draining ending condition is satisfied, the processing by the controller 3 proceeds to step S403, in which the controller 3 opens the second open-close valve 23 and closes the third open-close valve 24. Then, the controller 3 ends the draining operation. By contrast, in step S402, when the draining ending condition is not satisfied, the controller 3 repeatedly carries out step S402 until the draining ending condition is satisfied.
As described above, the evaporation mechanism 2 of the refrigeration apparatus 103 according to Embodiment 3 includes the first bypass circuit 20 which has the first inlet portion 20a branching off from a refrigerant pipe 17 that is located between the receiver 12 and the first open-close valve 13, which has the first outlet portion 20b connected to the compressor 10, and which forms part of the refrigerant circuit. The evaporation mechanism 2 includes the second bypass circuit 21 which has the second inlet portion 21a branching off from the first bypass circuit 20, which allows passage of the liquid refrigerant 16a stored in the accumulator 16, which has the second outlet portion 21b connected to part of the first bypass circuit 20 that is located between the second inlet portion 21a and the compressor 10, and which has part of the refrigerant circuit. The evaporation mechanism 2 includes the expansion valve 25 provided in part of the first bypass circuit 20 that is located between the first inlet portion 20a of the first bypass circuit 20 and the second inlet portion 21a of the second bypass circuit 21. The evaporation mechanism 2 includes the internal heat exchanger 26 which causes heat exchange to be performed between refrigerant that flows through part of the main circuit 1 that is located between the receiver 12 and the first inlet portion 20a and refrigerant that flows through part of the first bypass circuit 20 that is located between the expansion valve 25 and the second inlet portion 21a. The evaporation mechanism 2 includes the second open-close valve 23 provided in part of the first bypass circuit 20 that is located between the second inlet portion 21a and the second outlet portion 21b and the third open-close valve 24 provided in part of the second bypass circuit 21 that is located between the second inlet portion 21a and the accumulator 16. The controller 3 closes the second open-close valve 23 and opens the third open-close valve 24 to cause liquid refrigerant that flows into the first bypass circuit 20 and is decompressed by the expansion valve 25 to exchange heat, in the internal heat exchanger 26, with liquid refrigerant that flows out from the condenser 11, and then causes the liquid refrigerant to flow into the second bypass circuit 21 to evaporate the liquid refrigerant 16a stored in the accumulator 16.
Therefore, in the refrigeration apparatus 103 according to Embodiment 3, after the precooling operation, it is possible to evaporate the liquid refrigerant 16a stored in the accumulator 16, using the evaporation mechanism 2. Thus, when the precooling operation is ended and the cooling operation is started, it is possible to promote drainage from the accumulator 16 and reduce deterioration of the refrigeration capacity.

Embodiment 4

Next, the following description concerning a refrigeration apparatus 104 according to Embodiment 4 is made with reference to Figs. 11 and 12 by also referring to Figs. 2 to 5. Fig. 11 is a refrigerant circuit diagram of the refrigeration apparatus 104 according to Embodiment 4. Fig. 12 is a flow chart of the draining operation mode S4 of the refrigeration apparatus 104 according to Embodiment 4. It should be noted that components that are same as those of Embodiment 1 will be denote by the same reference signs, and their descriptions will thus be omitted as appropriate.
As illustrated in Fig. 11, the refrigeration apparatus 104 according to Embodiment 4 includes the main circuit 1, the evaporation mechanism 2, and the controller 3. The main circuit 1 serves as a refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by the refrigerant pipes 17 and in which the refrigerant is circulated. The compressor 10, the condenser 11, the receiver 12, and the accumulator 16 are provided in the outdoor unit 200. The first open-close valve 13, the expansion mechanism 14, and the evaporator 15 are provided in the indoor unit 300. The evaporation mechanism 2 is configured to evaporate liquid refrigerant 16a stored in the accumulator 16. The controller 3 is configured to control the main circuit 1 and the evaporation mechanism 2. The compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 have the same configurations as those in Embodiment 1 which are described above.
As illustrated in Fig. 11, the evaporation mechanism 2 is the heating unit 27 which is provided outside the accumulator 16 to heat and evaporate the liquid refrigerant 16a stored in the accumulator 16, after the precooling operation. The heating unit 27 is, for example, a heater. The controller 3 of the refrigeration apparatus 104 according to Embodiment 4 exerts a control of causing the heating unit 27 to evaporate the liquid refrigerant 16a stored in the accumulator 16. The heating unit 27 is not limited to the heater, but may be another type of heating device as long as it can evaporate the liquid refrigerant 16a stored in the accumulator 16.
Next, operation modes of the refrigeration apparatus 104 according to Embodiment 4 will be described. As illustrated in Fig. 2, also, in the refrigeration apparatus 104 according to Embodiment 4, the cooling operation mode S1, the defrosting operation mode S2, the precooling operation mode S3, and the draining operation mode S4 are applied in this order as in the refrigeration apparatus 101 of Embodiment 1. After the draining operation mode S4 ends, the cooling operation mode S1 is re-started.
In the cooling operation mode S1 of the refrigeration apparatus 104 according to Embodiment 4, the steps are carried out as indicated in Fig. 3. In the refrigeration apparatus 104 according to Embodiment 4, the setting of the refrigerant circuit in step S101 is not performed, but after the refrigerant operation is started, step S102 is carried out. Steps S102 to S110 are the same as those in Embodiment 1, and their detailed descriptions will thus be omitted.
In the defrosting operation mode S2 of the refrigeration apparatus 104 according to Embodiment 4, the steps are carried out as indicated in Fig. 4. The defrosting operation mode S2 is the same as that in Embodiment 1, and its detailed description will thus be omitted.
In the precooling operation mode S3 of the refrigeration apparatus 104 according to Embodiment 4, the steps are carried out as indicated in Fig. 5. In the refrigeration apparatus 104 according to Embodiment 4, the setting of the refrigerant circuit in step S116 is not performed, but after the precooling operation is started, step S117 is carried out. Steps S117 to S121 are the same as those in Embodiment 1, and their detailed descriptions will thus be omitted.
Next, the draining operation mode S4 of the refrigeration apparatus 104 according to Embodiment 4 will be described with reference to Fig. 12. The controller 3 starts the draining operation after ending the precooling operation as indicated in Fig. 5. First, as indicated in Fig. 12, in step S501 after the draining operation is started, the controller 3 turns on the heater, which is the heating unit 27, and evaporates, using the heater, the liquid refrigerant 16a stored in the accumulator 16. Gas refrigerant produced by evaporation of the liquid refrigerant 16a is sucked into the compressor 10.
Next, in step S502, the controller 3 determines whether the draining ending condition is satisfied or not. The draining ending condition is, for example, whether a predetermined target time period elapses or not, whether the temperature in the accumulator 16 reaches a target temperature or not, or whether the temperature of the suction pipe of the compressor 10 reaches a target temperature or not. When the draining ending condition is satisfied, the processing by the controller 3 proceeds to step S503, in which the controller 3 turns off the heater. Then, the controller 3 ends the draining operation. By contrast, in step S502, when the draining ending condition is not satisfied, the controller 3 repeatedly carries out step S502 until the draining ending condition is satisfied.
As described above, the evaporation mechanism 2 of the refrigeration apparatus 104 according to Embodiment 4 is the heating unit 27 which heats the liquid refrigerant 16a stored in the accumulator 16. The controller 3 exerts a control of causing the heating unit 27 to evaporate the liquid refrigerant 16a stored in the accumulator 16.
Therefore, in the refrigeration apparatus 104 according to Embodiment 4, after the precooling operation, it is possible to evaporate, with the evaporation mechanism 2, the liquid refrigerant 16a stored in the accumulator 16. Thus, when the precooling operation is ended and the cooling operation is started, it is possible to promote drainage of liquid from the accumulator 16 and reduce deterioration of the refrigeration capacity.

Embodiment 5

Next, the following description concerning a refrigeration apparatus 105 according to Embodiment 5 is made with reference to Figs. 13 to 15 by also referring to Figs. 3 and 4. Fig. 13 is a refrigerant circuit diagram of the refrigeration apparatus 105 according to Embodiment 5. Fig. 14 is a flow chart of operation modes of the refrigeration apparatus 105 according to Embodiment 5. Fig. 15 is a flow chart of the precooling operation mode S3 of the refrigeration apparatus 105 according to Embodiment 5. It should be noted that Regarding Embodiment 5, components that are the same as those in Embodiment 1 will be denoted by the same reference signs, and their descriptions will be omitted as appropriate.
As illustrated in Fig. 13, the refrigeration apparatus 105 according to Embodiment 5 includes the main circuit 1, the evaporation mechanism 2, and the controller 3. The main circuit 1 serves as a refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by refrigerant pipes 17 and in which the refrigerant is circulated. The compressor 10, the condenser 11, the receiver 12, and the accumulator 16 are provided in the outdoor unit 200. The first open-close valve 13, the expansion mechanism 14, and the evaporator 15 are provided in the indoor unit 300. The evaporation mechanism 2 is configured to evaporate liquid refrigerant that flows through a refrigerant pipe 17 located on the suction side of the accumulator 16. The controller 3 is configured to control the main circuit 1 and the evaporation mechanism 2. The compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 have the same configurations as those in Embodiment 1 which are described above.
The evaporation mechanism 2 is configured to evaporate in the precooling operation, evaporate liquid refrigerant that flows through a refrigerant pipe 17 that is located on the suction side of the accumulator 16. As illustrated in Fig. 13, the evaporation mechanism 2 includes the first bypass circuit 20, the second open-close valve 23, the third open-close valve 24, and the internal heat exchanger 26.
The first bypass circuit 20 has the inlet portion 20a branching off from a refrigerant pipe 17 of the main circuit 1 that is located between the compressor 10 and the condenser 11, has an outlet portion 20b connected to a refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the condenser 11, and forms part of the refrigerant circuit.
The second open-close valve 23 is provided in a refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the outlet portion 20b of the first bypass circuit 20. The second open-close valve 23 is, for example, a solenoid valve, and is controlled by the controller 3.
The third open-close valve 24 is provided in the first bypass circuit 20. The third open-close valve 24 is, for example, a solenoid valve, and is controlled by the controller 3.
The internal heat exchanger 26 is configured to cause heat exchange to be performed between high-pressure refrigerant that flows through the first bypass circuit 20 and low-pressure refrigerant that flows between the evaporator 15 and the accumulator 16.
The controller 3 of the refrigeration apparatus 105 according to Embodiment 5 closes the second open-close valve 23 and opens the third open-close valve 24 to cause heat exchange to be performed, in the internal heat exchanger 26, between refrigerant that is discharged from the compressor 10 and flows in the first bypass circuit 20 and refrigerant that flows between the evaporator 15 and the accumulator 16, thereby evaporating the liquid refrigerant that flows through a refrigerant pipe 17 that is located on the suction side of the accumulator 16.
Next, operation modes of the refrigeration apparatus 105 according to Embodiment 5 will be described. As illustrated in Fig. 14, in the refrigeration apparatus 105 according to Embodiment 5, the cooling operation mode S1, the defrosting operation mode S2, and the precooling operation mode S3 are applied in this order. In the refrigeration apparatus 105 according to Embodiment 5, the draining operation is performed in the precooling operation mode S3. After the precooling operation mode S3 ends, the cooling operation mode S1 is re-started.
In the cooling operation mode S1 of the refrigeration apparatus 105 according to Embodiment 5, the steps are carried out as indicated in Fig. 3. First, the refrigerant operation starts, in step S101, the controller 3 sets the refrigerant circuit in the cooling operation mode S1. The refrigerant circuit is set to open the second open-close valve 23 and close the third open-close valve 24. That is, in step S101, the refrigerant circuit is set such that the refrigerant flows only in the main circuit 1.
Steps S102 to S110 are the same as those in Embodiment 1, and its detailed description will thus be omitted.
Next, in the defrosting operation mode S2 of the refrigeration apparatus 105 according to Embodiment 5, the steps are carried out as indicated in Fig. 4. The defrosting operation mode S2 is the same as in Embodiment 1, and its detailed description will thus be omitted.
Next, the precooling operation mode S3 of the refrigeration apparatus 105 according to Embodiment 5 will be described with reference to Fig. 15. The controller 3 starts the precooling operation after ending the defrosting operation as indicated in Fig. 4. First, as indicated in Fig. 15, after the start of the precooling operation starts, in step S601, the controller 3 closes the second open-close valve 23 and opens the third open-close valve 24. Then, high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows into the first bypass circuit 20 via the first inlet portion 20a.
Next, in step S602, the controller 3 opens the first open-close valve 13. As a result, the temperature of refrigerant that flows through the evaporator 15 rises.
Next, in step S603, the controller 3 determines whether a relationship between an evaporating temperature Te, which is the temperature of refrigerant in the evaporator 15, and a target value Te_set of the evaporating temperature Te satisfies Te > Te_set or not. When Te > Te_set is satisfied, the processing by the controller 3 proceeds to step S604, in which the controller 3 turns on the condenser fan 11a and turns on the compressor 10. Then, high-pressure gas refrigerant that flows through the first bypass circuit 20 and low-pressure liquid refrigerant that flows through a refrigerant pipe 17 that is located between the evaporator 15 and the accumulator 16 exchange heat with each other in the internal heat exchanger 26. As a result, the liquid refrigerant that flows through a refrigerant pipe 17 that is located on the suction side of the accumulator 16 evaporates to change into gas refrigerant. It is therefore possible to reduce the amount of liquid refrigerant that returns to the accumulator 16.
By contrast, in step S603, when Te > Te_set is not satisfied, the controller 3 repeatedly carries out step S603 until Te > Te_set is satisfied.
Next, in step S605, the controller 3 determines whether the precooling ending condition is satisfied or not. The precooling ending condition I, for example, whether a predetermined target time period elapses or not, or whether the temperature of an outlet pipe of the evaporator 15 reaches a predetermined temperature or not. In step S605, when the precooling ending condition is satisfied, the processing by the controller 3 proceeds to step S606. By contrast, in step S605, when the precooling ending condition is not satisfied, the controller 3 repeatedly carries out step S605 until the precooling ending condition is satisfied.
Next, in step S606, the controller 3 determines whether the draining ending condition is satisfied or not. The draining ending condition is, for example, whether a predetermined target time period elapses or not, whether the temperature in the accumulator 16 reaches a target temperature or not, or whether the temperature of the suction pipe of the compressor 10 reaches a target temperature or not. When the draining ending condition is satisfied, the processing by the controller 3 proceeds to step S607, in which the controller 3 opens the second open-close valve 23 and closes the third open-close valve 24. In step S608, the controller 3 turns on the evaporator fan 15a. Then, the controller 3 ends the precooling operation.
By contrast, in step S606, when the draining ending condition is not satisfied, the controller 3 repeatedly carries out step S606 until the draining ending condition is satisfied.
As described above, the refrigeration apparatus 105 according to Embodiment 5 includes: the main circuit 1 serving as a refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by refrigerant pipes 17 and in which the refrigerant is circulated; an evaporation mechanism 2 configured to evaporate in the precooling operation which is performed to cool the evaporator 15, liquid refrigerant that flows through a refrigerant pipe 17 that is located on the suction side of the accumulator 16; and a controller 3 configured to control the main circuit 1 and the evaporation mechanism 2.
The evaporation mechanism 2 includes the first bypass circuit 20 which has the inlet portion 20a branching off from a refrigerant pipe 17 of the main circuit 1 that is located between the compressor 10 and the condenser 11, which has the outlet portion 20b connected to a refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the condenser 11, and which forms part of the refrigerant circuit. The evaporation mechanism 2 includes the second open-close valve 23 provided in a refrigerant pipe 17 of the main circuit 1 that is located between the inlet portion 20a and the outlet portion 20b and the third open-close valve 24 provided in the first bypass circuit 20. The evaporation mechanism 2 includes the internal heat exchanger 26 configured to cause heat exchange to be performed between refrigerant that flows through the first bypass circuit 20 and refrigerant that flows between the evaporator 15 and the accumulator 16. The controller 3 closes the second open-close valve 23 and opens the third open-close valve 24 to cause heat exchange to be performed, in the internal heat exchanger 26, between refrigerant that is discharged from the compressor 10 and flows in the first bypass circuit 20 and refrigerant that flows between the evaporator 15 and the accumulator 16, and cause the liquid refrigerant that flows through the refrigerant pipe 17 that is located on the suction side of the accumulator 16 to be evaporated.
Therefore, in the refrigeration apparatus 105 according to Embodiment 5, in the precooling operation, it is possible to evaporate with the evaporation mechanism 2, the liquid refrigerant that flows through the refrigerant pipe 17 that is located on the suction side of the accumulator 16, and is thus possible to reduce the amount of liquid refrigerant that returns to the accumulator 16. Accordingly, when the precooling operation is ended and the cooling operation is started, it is possible to promote drainage of liquid from the accumulator 16 and improve the refrigeration capacity.

Embodiment 6

Next, the following description concerning a refrigeration apparatus 106 according to Embodiment 6 is made with reference to Figs. 16 and 17 by also referring to Figs. 3, 4, and 14. Fig. 16 is a refrigerant circuit diagram of the refrigeration apparatus 106 according to Embodiment 6. Fig. 17 is a flow chart of the precooling operation mode S3 of the refrigeration apparatus 106 according to Embodiment 6. It should be noted that components that are same as those in Embodiment 1 will be denoted by the same reference signs, and their descriptions will thus be omitted as appropriate.
As illustrated in Fig. 16, the refrigeration apparatus 106 according to Embodiment 6 includes the main circuit 1, the evaporation mechanism 2, and the controller 3. The main circuit 1 serves as a refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by refrigerant pipes 17 and in which refrigerant is circulated. The compressor 10, the condenser 11, the receiver 12, and the accumulator 16 are provided in the outdoor unit 200. The first open-close valve 13, the expansion mechanism 14, and the evaporator 15 are provided in the indoor unit 300. The evaporation mechanism 2 is configured to evaporate liquid refrigerant that flows through a refrigerant pipe 17 that is located on the suction side of the accumulator 16. The controller 3 is configured to control the main circuit 1 and the evaporation mechanism 2. The compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 have the same configurations as those in Embodiment 1 which are described above.
The evaporation mechanism 2 is configured to evaporate, in the precooling operation, liquid refrigerant that flows through the refrigerant pipe 17 that is located on the suction side of the accumulator 16. As illustrated in Fig. 16, the evaporation mechanism 2 includes the first bypass circuit 20, the second bypass circuit 21, the expansion valve 25, a first internal heat exchanger 28, the second open-close valve 23, the third open-close valve 24, and a second internal heat exchanger 29.
The first bypass circuit 20 has the first inlet portion 20a branching off from a refrigerant pipe 17 of the main circuit 1 that is located between the receiver 12 and the first open-close valve 13, has the first outlet portion 20b connected to the compressor 10, and forms part of the refrigerant circuit.
The second bypass circuit 21 has the second inlet portion 21a branching off from the first bypass circuit 20, has the second outlet portion 21b connected to part of the first bypass circuit 20 that is located between the second inlet portion 21a and the compressor 10, and forms part of the refrigerant circuit.
The expansion valve 25 is provided in part of the first bypass circuit 20 that is located between the first inlet portion 20a of the first bypass circuit 20 and the second inlet portion 21a of the second bypass circuit 21. The expansion valve 25 is configured to decompress and expand liquid refrigerant that flows into the first bypass circuit 20 via the first inlet portion 20a. The expansion valve 25 is, for example, an electronic expansion valve whose opening degree is variably controlled.
The first internal heat exchanger 28 is configured to cause heat exchange to be performed between high-pressure refrigerant that flows in part of the main circuit 1 that is located between the receiver 12 and the first inlet portion 20a and intermediate-pressure refrigerant that flows in part of the first bypass circuit 20 that is located between the expansion valve 25 and the second inlet portion 21a.
The second open-close valve 23 is provided in part of the first bypass circuit 20 that is located between the second inlet portion 21a and the second outlet portion 21b. The second open-close valve 23 is, for example, a solenoid valve, and is controlled by the controller 3.
The third open-close valve 24 is provided in the second bypass circuit 21. The third open-close valve 24 is, for example, a solenoid valve, and is controlled by the controller 3.
The second internal heat exchanger 29 is configured to cause heat exchange to be performed between intermediate-pressure refrigerant that flows through the second bypass circuit 21 and low-pressure refrigerant that flows between the evaporator 15 and the accumulator 16.
The controller 3 of the refrigeration apparatus 106 according to Embodiment 6 closes the second open-close valve 23 and opens the third open-close valve 24 to cause heat exchange to be performed, in the second internal heat exchanger 29, between refrigerant that flows through the second bypass circuit 21 and refrigerant that flows between the evaporator 15 and the accumulator 16, and to cause the liquid refrigerant that flows through the refrigerant pipe 17 that is located on the suction side of the accumulator 16 to be evaporated.
Next, operation modes of the refrigeration apparatus 106 according to Embodiment 6 will be described. As indicated in Fig. 14, in the refrigeration apparatus 106 according to Embodiment 6, the cooling operation mode S1, the defrosting operation mode S2, and the precooling operation mode S3 are applied in this order. In the refrigeration apparatus 106 according to Embodiment 6, the draining operation is performed in the precooling operation mode S3. After the precooling operation mode S3 ends, the cooling operation mode S1 is re-started.
In the cooling operation mode S1 of the refrigeration apparatus 106 according to Embodiment 6, steps are carried out as indicated in Fig. 3. First, after the refrigerant operation starts, in step S101, the controller 3 sets the refrigerant circuit in the cooling operation mode S1. The refrigerant circuit is set to open the second open-close valve 23 and close the third open-close valve 24. That is, in step S101, the refrigerant circuit is set such that refrigerant flows in the main circuit 1 and the first bypass circuit 20.
Steps S102 to S110 are the same as those in Embodiment 1, and their detailed descriptions will thus be omitted.
Next, in the defrosting operation mode S2 of the refrigeration apparatus 106 according to Embodiment 6, steps are carried out as indicated in Fig. 4. The defrosting operation mode S2 is the same as that in Embodiment 1, and its detailed description will thus be omitted.
Next, the precooling operation mode S3 of the refrigeration apparatus 106 according to Embodiment 6 will be described with reference to Fig. 17. The controller 3 starts the precooling operation after ending the defrosting operation as indicated in Fig. 4. First, as indicated in Fig. 17, after the precooling operation starts, in step S701, the controller 3 closes the second open-close valve 23 and opens the third open-close valve 24. Then, gas refrigerant that exchanges heat, in the first internal heat exchanger 28, with liquid refrigerant that flows into the first bypass circuit 20 via the first inlet portion 20a, that is decompressed by the expansion valve 25, and that flows out from the condenser 11 flows into the second bypass circuit 21 via the second inlet portion 21a.
Next, in step S702, the controller 3 opens the first open-close valve 13. As a result, the temperature of refrigerant that flows through the evaporator 15 rises.
Next, in step S703, the controller 3 determines whether the relationship between an evaporating temperature Te, which is the temperature of refrigerant in the evaporator 15, and a target value Te_set of the evaporating temperature Te satisfies Te > Te_set or not. When Te > Te_set is satisfied, the processing by the controller 3 proceeds to step S704, in which the controller 3 turns on the condenser fan 11a and turns on the compressor 10. Then, intermediate-pressure liquid refrigerant that flows through the second bypass circuit 21 and low-pressure liquid refrigerant that flows between the evaporator 15 and the accumulator 16 exchanges heat with each other in the second internal heat exchanger 29. As a result, the liquid refrigerant that flows through the refrigerant pipe 17 that is located on the suction side of the accumulator 16 evaporates to change into gas refrigerant. It is therefore possible to reduce the amount of liquid refrigerant that returns to the accumulator 16.
By contrast, in step S703, when Te > Te_set is not satisfied, the controller 3 repeatedly carries out step S703 until Te > Te_set is satisfied.
Next, in step S705, the controller 3 determines whether the precooling ending condition is satisfied or not. The precooling ending condition is, for example, whether a predetermined target time period elapses or not, or whether the temperature of the outlet pipe of the evaporator 15 reaches a predetermined temperature or not. In step S705, when the precooling ending condition is satisfied, the processing by the controller 3 proceeds to step S706. By contrast, in step S705, when the precooling ending condition is not satisfied, the controller 3 repeatedly carries out step S705 until the precooling ending condition is satisfied.
Next, in step S706, the controller 3 determines whether the draining ending condition is satisfied or not. The draining ending condition is, for example, whether a predetermined target time period elapses or not, whether the temperature in the accumulator 16 reaches a target temperature or not, or whether the temperature of the suction pipe of the compressor 10 reaches a target temperature or not. When the draining ending condition is satisfied, the processing by the controller 3 proceeds to step S707, in which the controller 3 opens the second open-close valve 23 and closes the third open-close valve 24. In step S708, the controller 3 turns on the evaporator fan 15a. Then, the controller 3 ends the precooling operation.
By contrast, in step S706, when the draining ending condition is not satisfied, the controller 3 repeatedly carries out step S706 until the draining ending condition is satisfied.
As described above, the evaporation mechanism 2 of the refrigeration apparatus 106 according to Embodiment 6 includes the first bypass circuit 20 which has the first inlet portion 20a branching off from a refrigerant pipe 17 of the main circuit 1 that is located between the receiver 12 and the first open-close valve 13, which has the first outlet portion 20b connected to the compressor 10, and which forms part of the refrigerant circuit. The evaporation mechanism 2 includes the second bypass circuit 21 which has the second inlet portion 21a branching off from the first bypass circuit 20, which has the second outlet portion 21b connected to part of the first bypass circuit 20 that is located between the second inlet portion 21a and the compressor 10, and which forms part of the refrigerant circuit. Furthermore, the evaporation mechanism 2 includes the expansion valve 25 provided in part of the first bypass circuit 20 that is located between the first inlet portion 20a of the first bypass circuit 20 and the second inlet portion 21a of the second bypass circuit 21 and the first internal heat exchanger 28 configured to cause heat exchange to be performed between refrigerant that flows in part of the main circuit 1 that is located between the receiver 12 and the first inlet portion 20a and refrigerant that flows in part of the first bypass circuit 20 that is located between the expansion valve 25 and the second inlet portion 21a. The evaporation mechanism 2 includes the second open-close valve 23 provided in part of the first bypass circuit 20 that is located between the second inlet portion 21a and the second outlet portion 21b and the third open-close valve 24 provided in the second bypass circuit 21. The evaporation mechanism 2 includes the second internal heat exchanger 29 configured to cause heat exchange to be performed between refrigerant that flows through the second bypass circuit 21 and refrigerant that flows between the evaporator 15 and the accumulator 16. The controller 3 closes the second open-close valve 23 and opens the third open-close valve 24 to cause heat exchange to be performed, in the second internal heat exchanger 29, between the refrigerant that flows through the second bypass circuit 21 and the refrigerant that flows between the evaporator 15 and the accumulator 16, and to cause the liquid refrigerant that flows through the refrigerant pipe 17 located on the suction side of the accumulator 16 to be evaporated.
Therefore, in the refrigeration apparatus 106 according to Embodiment 6, in the precoding operation, it is possible to evaporate, with the evaporation mechanism 2, the liquid refrigerant that flows through the refrigerant pipe 17 that is located on the suction side of the accumulator 16. It is therefore possible to reduce the amount of liquid refrigerant that returns to the accumulator 16. Accordingly, when the precooling operation is ended and the cooling operation is started, it is possible to promote drainage of liquid from the accumulator 16 and improve the refrigeration capacity.

Embodiment 7

Next, the following description concerning a refrigeration apparatus 107 according to Embodiment 7 is made with reference to Figs. 18 and 19 by also referring to with reference to Figs. 3, 4, and 14. Fig. 18 is a refrigerant circuit diagram of the refrigeration apparatus 107 according to Embodiment 7. Fig. 19 is a flow chart of the precooling operation mode S3 of the refrigeration apparatus 107 according to Embodiment 7. It should be noted that regarding Embodiment 7, components that are the same as those in Embodiment 1 are denoted by the same reference signs, and their descriptions will thus be omitted as appropriate.
As illustrated in Fig. 18, the refrigeration apparatus 107 according to Embodiment 7 includes the main circuit 1, the evaporation mechanism 2, and the controller 3. The main circuit 1 serves as a refrigerant circuit in which the compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 are sequentially connected by refrigerant pipes 17 and in which the refrigerant is circulated. The compressor 10, the condenser 11, the receiver 12, and the accumulator 16 are provided in the outdoor unit 200. The first open-close valve 13, the expansion mechanism 14, and the evaporator 15 are provided in the indoor unit 300. The evaporation mechanism 2 is configured to evaporate liquid refrigerant that flows through a refrigerant pipe 17 that is located on the suction side of the accumulator 16. The controller 3 is configured to control the main circuit 1 and the evaporation mechanism 2. The compressor 10, the condenser 11, the receiver 12, the first open-close valve 13, the expansion mechanism 14, the evaporator 15, and the accumulator 16 have the same configurations as those in Embodiment 1 which are described above.
As illustrated in Fig. 18, the evaporation mechanism 2 is the heating unit 27 configured to heat, in the precooling operation, liquid refrigerant that flows through a refrigerant pipe 17 located upstream of the accumulator 16 and that is sucked into the accumulator 16. The heating unit 27 is, for example, a heater. The controller 3 of the refrigeration apparatus 107 according to Embodiment 7 exerts a control of causing the heating unit 27 to evaporate the liquid refrigerant that flows through the refrigerant pipe 17 located on the suction side of the accumulator 16. The heating unit 27 is not limited to the heater, but may be another type of heating device as long as it can evaporate the liquid refrigerant that flows through the refrigerant pipe 17 located on the suction side of the accumulator 16.
Next, operation modes of the refrigeration apparatus 107 according to Embodiment 7 will be described. As illustrated in Fig. 14, in the refrigeration apparatus 107 according to Embodiment 7, the cooling operation mode S1, the defrosting operation mode S2, and the precooling operation mode S3 are applied in this order. In the refrigeration apparatus 107 according to Embodiment 7, the draining operation is performed during the precooling operation mode S3. When the precooling operation mode S3 ends, the cooling operation mode S1 is re-started.
In the cooling operation mode S1 of the refrigeration apparatus 107 according to Embodiment 7, the steps are carried out as indicated in Fig. 3. In the refrigeration apparatus 107 according to Embodiment 7, the setting of the refrigerant circuit in step S101 is not performed, and after the refrigerant operation starts, step S102 is carried out. Steps S102 to S110 are the same as those in those in Embodiment 1 which are described above, and their detailed descriptions will thus be omitted.
Next, in the defrosting operation mode S2 of the refrigeration apparatus 107 according to Embodiment 7, the steps are carried out as indicated in Fig. 4. The defrosting operation mode S2 is the same as that in Embodiment 1 that is described above, and its detailed description will thus be omitted.
Next, the precooling operation mode S3 of the refrigeration apparatus 107 according to Embodiment 7 will be described with reference to Fig. 19. The controller 3 starts the precooling operation after ending the defrosting operation as indicated in Fig. 4. First, as indicated in Fig. 19, after the precooling operation starts, in step S801, the controller 3 turns on the heater, which is the heating unit 27.
Next, in step S802, the controller 3 opens the first open-close valve 13. As a result, the temperature of refrigerant that flows through the evaporator 15 rises.
Next, in step S803, the controller 3 determines whether the relationship between an evaporating temperature Te, which is the temperature of refrigerant in the evaporator 15, and a target value Te_set of the evaporating temperature Te satisfies Te > Te_set or not. When Te > Te_set is satisfied, the processing by the controller 3 proceeds to step S804, in which the controller 3 turns on the condenser fan 11a and turns on the compressor 10. As a result, the liquid refrigerant that flows through the refrigerant pipe 17 located on the suction side of the accumulator 16 is heated by the heating unit 27 to evaporate and thus change into gas refrigerant. It is therefore possible to reduce the amount of liquid refrigerant that returns to the accumulator 16.
By contrast, in step S803, when Te > Te_set is not satisfied, the controller 3 repeatedly carries out step S803 until Te > Te_set is satisfied.
Next, in step S805, the controller 3 determines whether the precooling ending condition is satisfied or not. The precooling ending condition is, for example, whether a predetermined target time period elapses or not, or whether the temperature of the outlet pipe of the evaporator 15 reaches a predetermined temperature or not. In step S805, when the precooling ending condition is satisfied, the processing by the controller 3 proceeds to step S806. By contrast, in step S805, when the precooling ending condition is not satisfied, the controller 3 repeatedly carries out step S805 until the precooling ending condition is satisfied.
Next, in step S806, the controller 3 determines whether a draining ending condition is satisfied or not. The draining ending condition is, for example, whether a predetermined target time period elapses or not, whether the temperature in the accumulator 16 reaches a target temperature or not, or whether the temperature of the suction pipe of the compressor 10 reaches a target temperature or not. When the draining ending condition is satisfied, the processing by the controller 3 proceeds to step S807, in which the controller 3 turns off the heater. In step S808, the controller 3 turns on the evaporator fan 15a. Then, the controller 3 ends the precooling operation.
By contrast, in step S806, when the draining ending condition is not satisfied, the controller 3 repeatedly carries out step S806 until the draining ending condition is satisfied.
As described above, the evaporation mechanism 2 of the refrigeration apparatus 107 according to Embodiment 7 is the heating unit 27 configured to heat liquid refrigerant that flows through the refrigerant pipe 17 located upstream of the accumulator 16 and that is sucked into the accumulator 16. The controller 3 exerts a control of causing the heating unit 27 to evaporate the liquid refrigerant that flows through the refrigerant pipe 17 located on the suction side of the accumulator 16.
Therefore, in the refrigeration apparatus 107 according to Embodiment 7, in the precooling operation, it is possible to evaporate, with the evaporation mechanism 2, the liquid refrigerant that flows through the refrigerant pipe 17 located on the suction side of the accumulator 16. Thus, it is possible to reduce the amount of liquid refrigerant that returns to the accumulator 16. Accordingly, when the precooling operation is ended and the cooling operation is started, it is possible to promote drainage of liquid from the accumulator 16 and improve the refrigeration capacity.
Although the above descriptions are made with respect to the refrigeration apparatuses (101 to 107) according to the embodiments, they are not limiting. For example, the configurations of the refrigeration apparatuses (101 to 107) are not limited to the configurations as illustrated in the figures, and the refrigeration apparatuses (101 to 107) may include other components. That is, the refrigeration apparatuses (101 to 107) encompass the range of variations in design change and application that are ordinarily made by a person with ordinary skill in the art without departing from their technical ideas.

Reference Signs List

1: main circuit, 2: evaporation mechanism, 3: controller, 10: compressor, 11: condenser, 11a: condenser fan, 12: receiver, 13: first open-close valve, 14: expansion mechanism, 15: evaporator, 15a: evaporator fan, 15b: heating unit, 16: accumulator, 16a: liquid refrigerant, 17: refrigerant pipe, 20: first bypass circuit, 20a: inlet portion (first inlet portion), 20b: outlet portion (first outlet portion), 21: second bypass circuit, 21a: second inlet portion, 21b: second outlet portion, 22: flow switching valve, 23: second open-close valve, 24: third open-close valve, 25: expansion valve, 26: internal heat exchanger, 27: heating unit, 28: first internal heat exchanger, 29: second internal heat exchanger, 101: refrigeration apparatus, 102: refrigeration apparatus, 103: refrigeration apparatus, 104: refrigeration apparatus, 105: refrigeration apparatus, 106: refrigeration apparatus, 107: refrigeration apparatus, 200: outdoor unit, 300: indoor unit

Claims

A refrigeration apparatus comprising:
a main circuit serving as a refrigerant circuit in which a compressor, a condenser, a receiver, a first open-close valve, an expansion mechanism, an evaporator, and an accumulator are sequentially connected by refrigerant pipes, and in which refrigerant is circulated;

an evaporation mechanism configured to evaporate, after a precooling operation is performed to cool the evaporator, liquid refrigerant stored in the accumulator, or configured to evaporate, during the precooling operation which is performed to cool the evaporator, liquid refrigerant that flows through one of the refrigerant pipes that is located on a suction side of the accumulator; and

a controller configured to control the main circuit and the evaporation mechanism.
The refrigeration apparatus of claim 1, wherein
the evaporation mechanism includes
a first bypass circuit having an inlet portion that branches off from one of the refrigerant pipes of the main circuit that is located between the condenser and the receiver, having an outlet portion connected to one of the refrigerant pipes of the main circuit that is located between the receiver and the first open-close valve, and forming part of the refrigerant circuit,

a second bypass circuit connecting the receiver and the accumulator,

flow switching valves provided at the inlet portion and the outlet portion, and each configured to switch a flow passage to be used, between a flow passage for refrigerant that flows through the receiver and a flow passage for refrigerant that flows through the first bypass circuit, and

a second open-close valve provided in the second bypass circuit, and

the controller is configured to cause each of the flow switching valves to switch the flow passage such that the refrigerant flows through the first bypass circuit, and is configured to open the second open-close valve to cause liquid refrigerant in the receiver to flow into the accumulator to evaporate the liquid refrigerant stored in the accumulator.
The refrigeration apparatus of claim 1, wherein
the evaporation mechanism includes
a first bypass circuit having an inlet portion that branches off from one of the refrigerant pipes of the main circuit that is located between the compressor and the condenser, allowing passage of the liquid refrigerant stored in the accumulator, having an outlet portion connected to one of the refrigerant pipes of the main circuit that is located between the inlet portion and the condenser, and forming part of the refrigerant circuit,

a second open-close valve provided at one of the refrigerant pipes of the main circuit that is located between the inlet portion and the outlet portion, and

a third open-close valve provided in part of the first bypass circuit that is located between the inlet portion and the accumulator, and

the controller is configured to close the second open-close valve and open the third open-close valve to cause gas refrigerant discharged from the compressor to flow into the first bypass circuit to evaporate the liquid refrigerant stored in the accumulator.
The refrigeration apparatus of claim 1, wherein
the evaporation mechanism includes
a first bypass circuit having a first inlet portion that branches off from one of the refrigerant pipes of the main circuit that is located between the receiver and the first open-close valve, having a first outlet portion connected to the compressor, and forming part of the refrigerant circuit,

a second bypass circuit having a second inlet portion that branches off from the first bypass circuit, allowing passage of the liquid refrigerant stored in the accumulator, having a second outlet portion connected to part of the first bypass circuit that is located between the second inlet portion and the compressor, and forming part of the refrigerant circuit,

an expansion valve provided in part of the first bypass circuit that is located between the first inlet portion of the first bypass circuit and the second inlet portion of the second bypass circuit,

an internal heat exchanger configured to cause heat exchange to be performed between refrigerant that flows in part of the main circuit that is located between the receiver and the first inlet portion and refrigerant that flows in part of the first bypass circuit that is located between the expansion valve and the second inlet portion,

a second open-close valve provided in part of the first bypass circuit that is located between the second inlet portion and the second outlet portion, and

a third open-close valve provided in part of the second bypass circuit that is located between the second inlet portion and the accumulator, and

the controller is configured to close the second open-close valve and open the third open-close valve to cause heat exchange to be performed, in the internal heat exchanger, between liquid refrigerant that flows into the first bypass circuit and that is decompressed by the expansion valve and liquid refrigerant that flows out from the condenser, and then to cause the liquid refrigerant to flow into the second bypass circuit to evaporate the liquid refrigerant stored in the accumulator.
The refrigeration apparatus of claim 1, wherein
the evaporation mechanism is a heating unit configured to heat the liquid refrigerant stored in the accumulator, and

the controller is configured to exert a control of causing the heating unit to evaporate the liquid refrigerant stored in the accumulator.
The refrigeration apparatus of claim 1, wherein
the evaporation mechanism includes
a first bypass circuit having an inlet portion that branches off from one of the refrigerant pipes of the main circuit that is located between the compressor and the condenser, having an outlet portion connected to one of the refrigerant pipes of the main circuit that is located between the inlet portion and the condenser, and forming part of the refrigerant circuit,

a second open-close valve provided in one of the refrigerant pipes of the main circuit that is located between the inlet portion and the outlet portion,

a third open-close valve provided in the first bypass circuit, and

an internal heat exchanger configured to cause heat exchange to be performed between refrigerant that flows through the first bypass circuit and refrigerant that flows between the evaporator and the accumulator, and

the controller is configured to close the second open-close valve and open the third open-close valve to cause heat exchange to be performed, in the internal heat exchanger, between refrigerant that is discharged from the compressor and flows through the first bypass circuit and refrigerant that flows between the evaporator and the accumulator, and to cause the liquid refrigerant that flows through the refrigerant pipe located on the suction side of the accumulator to be evaporated.
The refrigeration apparatus of claim 1, wherein
the evaporation mechanism includes
a first bypass circuit having a first inlet portion that branches off from one of the refrigerant pipes of the main circuit that is located between the receiver and the first open-close valve, having a first outlet portion connected to the compressor, and forming part of the refrigerant circuit,

a second bypass circuit having a second inlet portion that branches off from the first bypass circuit, having a second outlet portion connected to part of the first bypass circuit that is located between the second inlet portion and the compressor, and forming part of the refrigerant circuit,

an expansion valve provided in part of the first bypass circuit that is located between the first inlet portion of the first bypass circuit and the second inlet portion of the second bypass circuit,

a first internal heat exchanger configured to cause heat exchange to be performed between refrigerant that flows in part of the main circuit that is located between the receiver and the first inlet portion and refrigerant that flows through part of the first bypass circuit that is located between the expansion valve and the second inlet portion,

a second open-close valve provided in part of the first bypass circuit that is located between the second inlet portion and the second outlet portion,

a third open-close valve provided in the second bypass circuit, and

a second internal heat exchanger configured to cause heat exchange to be performed between refrigerant that flows through the second bypass circuit and refrigerant that flows between the evaporator and the accumulator, and

the controller is configured to close the second open-close valve and open the third open-close valve to cause heat exchange to be performed, in the second internal heat exchanger, between the refrigerant that flows through the second bypass circuit and the refrigerant that flows between the evaporator and the accumulator, and to cause the liquid refrigerant that flows through the refrigerant pipe located on the suction side of the accumulator to be evaporated.
The refrigeration apparatus of claim 1, wherein
the evaporation mechanism is a heating unit configured to heat liquid refrigerant that flows through one of the refrigerant pipes that is located upstream of the accumulator and that is sucked into the accumulator, and

the controller is configured to exert a control of causing the heating unit to evaporate the liquid refrigerant that flows through the refrigerant pipe located on the suction side of the accumulator.