WO2018073881A1

WO2018073881A1 - Refrigeration cycle system

Info

Publication number: WO2018073881A1
Application number: PCT/JP2016/080769
Authority: WO
Inventors: 千歳田中; 拓也松田; 野本　宗
Original assignee: 三菱電機株式会社
Priority date: 2016-10-18
Filing date: 2016-10-18
Publication date: 2018-04-26
Also published as: JPWO2018073881A1; JP6644160B2

Abstract

In a refrigeration cycle system (100) according to the present invention, a refrigerant sequentially circulates through a compressor (1), a first valve (6a), a first condenser (3a) that is arranged in a first space, a second valve (6b), an expansion valve (4), and an evaporator (5) that is arranged in a second space. A liquid transfer mechanism (41) transfers a fluid (20) from a fluid retainer part (10) to the first condenser (3a). A second condenser (3b) is connected in parallel to the first valve (6a), the first condenser (3a) and the second valve (6b), which are connected in series. The fluid retainer part (10) is connected to the first condenser (3a). In cases where the temperature in the first space is lower than the reference temperature, a control device (15) transfers the fluid (20) from the fluid retainer part (10) to the first condenser (3a) after closing the first valve (6a) and the second valve (6b).

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus, and more particularly to control of a refrigeration cycle apparatus performed in a low outdoor air cooling operation.

The cooling operation by the refrigeration cycle apparatus may be continuously performed for a certain period regardless of the outside temperature. For example, in a server room where the server computer is operating almost all year long, if the temperature rise in the server room due to the heat generated from the server computer is left unattended, the processing capacity of the server computer will drop and the server computer will fail and stop. It is also envisaged. In order to prevent such a situation, the cooling operation by the refrigeration cycle apparatus is usually performed throughout the year in the server room.

In a cooling operation (hereinafter also referred to as “low outdoor air cooling operation”) performed when the outside air temperature is lower than a reference temperature (for example, 0 ° C.), condensation of the gas refrigerant by the outdoor heat exchanger functioning as a condenser is performed. If performed excessively, the gas refrigerant in the outdoor heat exchanger may be reduced as compared with the normal cooling operation. When the gas refrigerant in the outdoor heat exchanger decreases, the condensation pressure decreases, so the compression ratio (= condensation pressure / evaporation pressure) decreases. Therefore, in the low outside air cooling operation, it is necessary to suppress the decrease in the condensation pressure and to secure a compression ratio necessary for efficient compressor operation.

For example, in the case of a refrigeration cycle apparatus including a plurality of outdoor heat exchangers, the condensation pressure is reduced by stopping the inflow of gas refrigerant to some of the outdoor heat exchangers and suppressing the condensation of the gas refrigerant during low outdoor air cooling operation. Can be suppressed. For example, in Japanese Utility Model Publication No. 61-116975 (Patent Document 1), a check valve or a solenoid valve is used to prevent gas refrigerant from flowing into some outdoor heat exchangers during low outdoor air cooling operation. Thus, a refrigerator that can suppress a decrease in the condensation pressure is disclosed.

Japanese Utility Model Publication No. 61-116975

Since the valve closing capability is not perfect, the refrigerant may not be completely stopped even if the valve is closed. Therefore, in a configuration in which a valve is used to stop the inflow of the gas refrigerant to the outdoor heat exchanger as disclosed in Japanese Utility Model Publication No. 61-116975 (Patent Document 1), the gas refrigerant gradually begins to flow from the valve. Leaks and flows into the outdoor heat exchanger, and the condensed liquid refrigerant accumulates in the outdoor heat exchanger. Therefore, the amount of refrigerant that circulates through the refrigeration cycle apparatus and repeats the phase change in the low outside air cooling operation (hereinafter also referred to as “circulating refrigerant amount”) decreases. As a result, the condensing pressure and the evaporating pressure are lowered from appropriate values, and it may be difficult to continue the low outside air cooling operation.

The present invention has been made to solve the above-described problems, and an object thereof is to stably perform a low outdoor air cooling operation.

In the refrigeration cycle apparatus according to the present invention, the refrigerant is a compressor, a first valve, a first condenser installed in the first space, a second valve, an expansion valve, and an evaporator installed in the second space. It cycles in order. The refrigeration cycle apparatus includes a second condenser, a fluid storage unit, a liquid moving mechanism, and a control device. The second condenser is installed in the first space. The fluid reservoir stores a fluid different from the refrigerant. The liquid moving mechanism moves the fluid from the fluid reservoir to the first condenser. The control device controls the first valve, the second valve, and the liquid moving mechanism. The second condenser is connected in parallel to the first valve, the first condenser, and the second valve connected in series. The fluid reservoir is connected to the first condenser. When the temperature of the first space is lower than the reference temperature, the control device moves the fluid from the fluid reservoir to the first condenser after closing the first valve and the second valve.

In the refrigeration cycle apparatus according to the present invention, the first valve and the second valve are closed during the low outdoor air cooling operation, and a fluid different from the refrigerant is moved from the fluid reservoir to the first condenser. When the first condenser is filled with the fluid, the amount of refrigerant that leaks from the first valve and the second valve and accumulates in the first condenser is suppressed, and thus the decrease in the amount of circulating refrigerant is suppressed. As a result, the low outside air cooling operation can be stably performed.

2 is a functional block diagram showing a configuration of a refrigeration cycle apparatus according to Embodiment 1. FIG. It is a figure for demonstrating the filling connection state of the refrigerator oil moving mechanism of FIG. It is a figure for demonstrating the collection | recovery connection state of the refrigerator oil moving mechanism of FIG. It is a flowchart for demonstrating the flow of the process which moves refrigerating machine oil between a refrigerating machine oil tank and a condenser. It is a flowchart for demonstrating the flow of the process of the refrigerating machine oil filling operation | movement of FIG. It is a flowchart for demonstrating the flow of a process of the refrigerating machine oil collection | recovery driving | operation of FIG. It is a flowchart for demonstrating the flow of the process performed according to the presence or absence of the stop operation of the refrigerating-cycle apparatus performed by the user. 6 is a functional block diagram showing a configuration in a cooling operation of a refrigeration cycle apparatus according to a modification of the first embodiment. FIG. It is a functional block diagram which shows the structure in the heating operation of the refrigeration cycle apparatus which concerns on the modification of Embodiment 1. 6 is a functional block diagram showing a configuration of a refrigeration cycle apparatus according to Embodiment 2. FIG. 6 is a flowchart for explaining a flow of processing of a refrigerating machine oil filling operation in a second embodiment. 6 is a flowchart for explaining a flow of processing of a refrigeration oil recovery operation in the second embodiment. 6 is a functional block diagram showing a configuration of a refrigeration cycle apparatus according to Embodiment 3. FIG. 10 is a flowchart for illustrating a flow of processing of refrigerating machine oil filling operation in a third embodiment.

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

Embodiment 1 FIG.
FIG. 1 is a functional block diagram showing the configuration of the refrigeration cycle apparatus 100 according to the first embodiment. As shown in FIG. 1, the refrigeration cycle apparatus 100 includes an outdoor unit 50 installed outdoors and an indoor unit 60 installed indoors.

The outdoor unit 50 includes the compressor 1, the

condensers

3a and 3b, the shut-off

valves

6a and 6b, the refrigerating machine oil tank 10, the refrigerating machine oil moving mechanism 41, the control device 15, and the temperature sensor TS1. The indoor unit 60 includes the expansion valve 4 and the evaporator 5. The refrigeration cycle apparatus 100 includes a refrigeration cycle in which refrigerant circulates in the order of the compressor 1, the

condensers

3 a and 3 b, the expansion valve 4, and the evaporator 5. The refrigerating machine oil tank 10 is compressed when the side connected to the compressor 1 is the upstream side of the condenser 3a and the side connected to the expansion valve 4 is the downstream side of the condenser 3a in the condenser 3a. The discharge port of the machine 1 and the downstream side of the condenser 3a, and the downstream side of the condenser 3a and the suction port of the compressor 1 are connected. The control device 15 may be included in the indoor unit 60, or may be disposed outside the outdoor unit 50 and the indoor unit 60.

The compressor 1 compresses the low-pressure gas refrigerant received from the evaporator 5 and outputs the high-pressure gas refrigerant to the

condensers

3a and 3b.

The condenser 3a and the condenser 3b are connected in parallel, and

close valves

6a and 6b are connected to the upstream and downstream of the condenser 3a, respectively. The closing valve 6a is a valve for closing the flow of refrigerant flowing from the compressor 1 to the condenser 3a, and the closing valve 6b is a valve for stopping the flow of refrigerant flowing from the condenser 3a to the expansion valve 4. The condenser 3a is connected between the shut-off

valves

6a and 6b. The condenser 3b is connected in parallel to the shutoff valve 6a, the condenser 3a, and the shutoff valve 6b connected in series.

The high-temperature and high-pressure gas refrigerant from the compressor 1 is condensed in the

condensers

3a and 3b and flows out into the expansion valve 4 as liquid refrigerant. From the

condensers

3a and 3b, heat (condensation heat) when the gas refrigerant is condensed to become a liquid refrigerant is released.

The liquid refrigerant from the

condensers

3a and 3b is adiabatically expanded and decompressed in the expansion valve 4, and flows out to the evaporator 5 as wet steam. As the expansion valve 4, for example, an electronically controlled expansion valve (LEV: Linear Expansion Valve) can be used.

The wet steam from the expansion valve 4 evaporates in the evaporator 5 and flows out into the compressor 1 as a gas refrigerant. In the evaporator 5, the liquid refrigerant takes heat (vaporization heat) from the room air and evaporates.

The refrigerating machine oil tank 10 stores refrigerating machine oil RO for filling the condenser 3a. In the present embodiment, the lubricating oil of the compressor 1 is used as the refrigerating machine oil RO. The refrigerator oil tank 10 is connected to the condenser 3a. It is desirable that the solubility of the refrigerant in the refrigerating machine oil RO is smaller than 20%. More preferably, the refrigerant and the refrigerating machine oil RO are incompatible with each other (the solubility of the refrigerant in the refrigerating machine oil RO is less than 1%).

The refrigerating machine oil moving mechanism 41 moves the refrigerating machine oil RO from the refrigerating machine oil tank 10 to the condenser 3a. The refrigerator oil moving mechanism 41 includes a four-way valve 11 and closing

valves

12 and 13. The four-way valve 11 is a valve that switches connection between the refrigerator oil tank 10 and the discharge port of the compressor 1 or connection between the refrigerator oil tank 10 and the suction port of the compressor 1. The stop valve 12 is connected between the discharge port of the compressor 1 and the four-way valve 11. The stop valve 13 is connected between the suction port of the compressor 1 and the four-way valve 11.

The four-way valve 11 switches the connection state between the compressor 1, the refrigerating machine oil tank 10, and the condenser 3a between the filling connection state and the recovery connection state. In the filling connection state, the discharge port of the compressor 1 and the refrigerating machine oil tank 10 are connected, and the suction port of the compressor 1 and the condenser 3 a are connected, so that the refrigerating machine oil RO is condensed from the refrigerating machine oil tank 10. The container 3a is filled. In the recovery connection state, the discharge port of the compressor 1 and the condenser 3a are connected, and the suction port of the compressor 1 and the refrigerating machine oil tank 10 are connected, so that the refrigerating machine oil RO is supplied from the condenser 3a to the refrigerating machine oil tank. 10 recovered.

The control device 15 controls the driving frequency of the compressor 1 to control the amount of refrigerant discharged from the compressor 1 per unit time. The control device 15 controls the degree of superheat of the gas refrigerant flowing out of the evaporator 5 so as to approach the optimum value by controlling the opening degree of the expansion valve 4. The control device 15 acquires the outside air temperature T0 from the temperature sensor TS1. When the outside air temperature T0 is lower than the reference temperature T1, the control device 15 controls the refrigerating machine oil moving mechanism 41 to perform a refrigerating machine oil filling operation for moving the refrigerating machine oil RO from the refrigerating machine oil tank 10 to the condenser 3a. The control device 15 controls the refrigerating machine oil moving mechanism 41 to perform a refrigerating machine oil recovery operation for recovering the refrigerating machine oil RO from the condenser 3a to the refrigerating machine oil tank 10.

The control device 15 includes a processor such as a CPU (Central Processing Unit). The control device 15 includes a non-volatile memory such as a flash memory. The memory stores, for example, an OS (Operating System) read out and executed by the CPU, various application programs (for example, a program for controlling the refrigerator oil transfer mechanism 41), and various data used by the programs. Can be saved.

In the low outside air cooling operation, the gas refrigerant is excessively condensed by the condenser 3a, and the gas refrigerant in the condenser 3a may be reduced as compared with the normal cooling operation. When the gas refrigerant in the condenser 3a decreases, the condensation pressure decreases, so the compression ratio decreases. In the low outside air cooling operation, it is necessary to suppress a decrease in the condensation pressure and to secure a compression ratio necessary for efficient compressor operation. Therefore, in Embodiment 1, in order to suppress condensation of the gas refrigerant by the condenser 3a, the

shutoff valves

6a and 6b are closed.

However, since the closing ability of the closing

valves

6a and 6b is not perfect, even if the closing

valves

6a and 6b are closed, the passage of the refrigerant may not be completely stopped. Therefore, the gas refrigerant gradually leaks from the

shutoff valves

6a and 6b and flows into the condenser 3a, and the condensed liquid refrigerant accumulates in the condenser 3a. Therefore, the amount of circulating refrigerant in the low outside air cooling operation is reduced. As a result, the condensing pressure and the evaporating pressure are lowered from appropriate values, and it may be difficult to continue the low outside air cooling operation.

Therefore, in the refrigeration cycle apparatus 100 according to the first embodiment, the

shutoff valves

6a and 6b are closed to prevent the refrigerant from flowing into the condenser 3a during the low outside air cooling operation, and the refrigeration machine oil moving mechanism 41 The refrigerating machine oil RO is moved from the refrigerating machine oil tank 10 to the condenser 3a. By filling the inside of the condenser 3a with the refrigerating machine oil RO in which the refrigerant is difficult to dissolve, the amount of refrigerant that leaks from the

stop valves

6a and 6b and accumulates in the condenser 3a is suppressed, and the decrease in the amount of circulating refrigerant is suppressed. The As a result, the low outside air cooling operation can be stably performed.

FIG. 2 is a diagram for explaining a filling connection state of the refrigerating machine oil moving mechanism 41 of FIG. In FIG. 2, the closing

valves

6a and 6b are closed, and the closing

valves

12 and 13 are opened. As shown in FIG. 2, the discharge port of the compressor 1 and the refrigerating machine oil tank 10 are connected, and the suction port of the compressor 1 and the condenser 3a are connected. Part of the gas refrigerant flowing out of the compressor 1 passes through the shut-off valve 12 and flows into the refrigerator oil tank 10. As the gas refrigerant flows into the refrigerator oil tank 10, the refrigerator oil RO is filled from the refrigerator oil tank 10 into the condenser 3a. As the refrigerating machine oil RO is filled in the condenser 3a, the refrigerant is returned from the condenser 3a to the suction port of the compressor 1. After the connection state of the refrigerating machine oil moving mechanism 41 shown in FIG. 2 is maintained for a certain period of time, filling of the refrigerating machine oil RO from the refrigerating machine oil tank 10 to the condenser 3a is completed.

FIG. 3 is a view for explaining a recovery connection state of the refrigerator oil moving mechanism 41 in FIG. In FIG. 3, the closing

valves

6a and 6b are closed, and the closing

valves

12 and 13 are opened. As shown in FIG. 3, the discharge port of the compressor 1 and the condenser 3a are connected, and the suction port of the compressor 1 and the refrigerator oil tank 10 are connected. A part of the gas refrigerant flowing out of the compressor 1 passes through the closing valve 12 and flows into the condenser 3a. As the gas refrigerant flows into the condenser 3a, the refrigeration oil RO is recovered from the condenser 3a to the refrigeration oil tank 10. As the refrigerating machine oil RO is recovered in the refrigerating machine oil tank 10, the refrigerant is returned from the compressor 1 to the condenser 3a. After the connection state of the refrigerating machine oil moving mechanism 41 shown in FIG. 3 is maintained for a predetermined time, the collection of the refrigerating machine oil RO from the condenser 3a to the refrigerating machine oil tank 10 is completed.

FIG. 4 is a flowchart for explaining the flow of processing for moving the refrigeration oil RO between the refrigeration oil tank 10 and the condenser 3a. The process shown in FIG. 4 is performed at regular time intervals in a main routine (not shown) that controls the refrigeration cycle operation. Hereinafter, the step is simply referred to as S.

As shown in FIG. 4, the control device 15 determines whether or not the outside air temperature T0 is lower than the reference temperature T1 in S11. When outside temperature T0 is smaller than reference temperature T1 (YES in S11), control device 15 advances the process to S12. The control device 15 determines whether or not the condenser 3a is filled with the refrigerating machine oil RO in S12. In the first embodiment, the control device 15 completes the charging of the refrigerating machine oil RO from the refrigerating machine oil tank 10 to the condenser 3a when the closing

valves

6a and 6b are closed, and the refrigerating machine oil RO is supplied to the condenser 3a. Is determined to be filled (YES). Further, the control device 15 completes the recovery of the refrigerating machine oil RO from the condenser 3a to the refrigerating machine oil tank 10 when the closing

valves

6a and 6b are not closed, and the refrigerating machine oil RO is not filled in the condenser 3a. (NO) is determined. If the condenser 3a is not filled with the refrigerating machine oil RO (NO in S12), the control device 15 advances the process to S120. After performing the refrigerating machine oil filling operation in S120, the control device 15 returns the process to the main routine. When condenser oil RO is filled in condenser 3a (YES in S12), control device 15 returns the process to the main routine.

When the outside air temperature T0 is equal to or higher than the reference temperature T1 (NO in S11), the control device 15 determines whether or not the refrigerator oil RO is filled in the condenser 3a in S13. When the refrigerator oil RO is filled in the condenser 3a (YES in S13), the controller 15 collects the refrigerator oil RO in the refrigerator oil tank 10 before switching the cooling operation from the low outside air cooling operation to the normal cooling operation. Advances the process to S130. The control device 15 returns the processing to the main routine after performing the refrigerating machine oil recovery operation in S130. When the condenser oil RO is not filled in the condenser 3a (NO in S13), the control device 15 returns the process to the main routine.

FIG. 5 is a flowchart for explaining the processing flow of the refrigerating machine oil filling operation (S120) of FIG. As shown in FIG. 5, the control device 15 closes the closing valve 6a and the closing valve 6b in S121, and advances the process to S122. The control device 15 switches the four-way valve 11 in S122 to set the connection state of the refrigerator oil movement mechanism 41 to the filling connection state, and advances the process to S123. The control device 15 opens the closing valve 12 and the closing valve 13 in S123, and advances the processing to S124. In S124, the control device 15 determines whether or not the condenser 3a is filled with the reference amount of the refrigerating machine oil RO. In the first embodiment, the control device 15 determines whether or not the time necessary for the reference amount of the refrigerating machine oil RO to move from the refrigerating machine oil tank 10 to the condenser 3a has elapsed in S124. When the time necessary for the reference amount of the refrigerating machine oil RO to move from the refrigerating machine oil tank 10 to the condenser 3a has elapsed (YES in S124), the control device 15 advances the process to S125. The control device 15 returns the processing to the main routine after closing the closing valve 12 and the closing valve 13 in S125. When the time necessary for the reference amount of the refrigerating machine oil RO to move from the refrigerating machine oil tank 10 to the condenser 3a has not elapsed (NO in S124), the control device 15 returns the process to S124.

In the first embodiment, the control device 15 determines whether or not the reference amount of the refrigerating machine oil RO has moved from the refrigerating machine oil tank 10 to the condenser 3a. In S124 of FIG. Is determined based on whether or not the time required to move from the compressor to the condenser 3a has elapsed. For example, the determination may be made based on whether or not the liquid amount in the refrigerator oil tank 10 is smaller than the threshold value by the liquid amount sensor. Good. The position of the refrigerating machine oil tank 10 is such that the position of the bottom surface of the space where the refrigerating machine oil RO in the refrigerating machine oil tank 10 is stored is higher than the liquid level when the refrigerating machine oil RO is filled in the condenser 3a with a reference amount. High is preferred.

FIG. 6 is a flowchart for explaining the processing flow of the refrigerating machine oil recovery operation (S130) of FIG. As shown in FIG. 6, the control device 15 switches the four-way valve 11 in S131 to set the connection state of the refrigerator oil moving mechanism 41 to the recovery connection state, and advances the process to S132. The control device 15 opens the closing valve 12 and the closing valve 13 in S132 and advances the process to S133. In S133, the control device 15 determines whether or not the reference amount of the refrigerating machine oil RO has been collected in the refrigerating machine oil tank 10. In the first embodiment, the control device 15 determines whether or not the time necessary for the reference amount of the refrigerating machine oil RO to move from the condenser 3a to the refrigerating machine oil tank 10 has elapsed in S133. When the time necessary for the reference amount of the refrigerating machine oil RO to move from the condenser 3a to the refrigerating machine oil tank 10 has elapsed (YES in S133), the control device 15 advances the process to S134. After closing the closing valve 12 and the closing valve 13 in S134, the control device 15 advances the process to S135. The control device 15 returns the processing to the main routine after opening the closing valve 6a and the closing valve 6b in S135. When the time necessary for the reference amount of the refrigerating machine oil RO to move from the condenser 3a to the refrigerating machine oil tank 10 has not elapsed (NO in S133), the control device 15 returns the process to S133.

In the first embodiment, the control device 15 determines whether or not the reference amount of the refrigerating machine oil RO has moved from the condenser 3a to the refrigerating machine oil tank 10, and in S133 of FIG. The determination is made based on whether or not the time required to move from 3a to the refrigerating machine oil tank 10 has elapsed. For example, the determination is made based on whether or not the amount of liquid in the refrigerating machine oil tank 10 has become larger than the threshold by the liquid amount sensor. May be.

When the operation of the refrigeration cycle apparatus 100 is started, it is desirable that the condenser 3a is not filled with the refrigeration oil RO. Therefore, in the first embodiment, the refrigerating machine oil recovery operation shown in FIG. 6 is performed even when the user performs a stop operation of the refrigerating cycle apparatus 100 and the condenser 3a is filled with the refrigerating machine oil RO.

FIG. 7 is a flowchart for explaining the flow of processing performed in accordance with whether or not the refrigeration cycle apparatus 100 is stopped by the user. As shown in FIG. 7, the control device 15 determines whether or not a stop operation of the refrigeration cycle apparatus 100 has been performed by the user in S <b> 21. When the stop operation of refrigeration cycle apparatus 100 is performed by the user (YES in S21), control device 15 advances the process to S22. In S22, the controller 15 determines whether or not the condenser 3a is filled with the refrigerating machine oil RO. If the condenser 3a is filled with the refrigerating machine oil RO (YES in S22), the control device 15 advances the process to S130 and performs the refrigerating machine oil recovery operation. After the refrigerating machine oil recovery operation is completed, the control device 15 stops the refrigeration cycle apparatus 100 in S23. When the condenser 3a is not filled with the refrigerating machine oil RO (NO in S22), the control device 15 advances the process to S23 and stops the refrigeration cycle apparatus.

As described above, according to the refrigeration cycle apparatus according to Embodiment 1, the shutoff valve is closed to prevent the refrigerant from flowing into the condenser during the low outside air cooling operation, and the refrigeration oil is refrigerated by the refrigeration oil moving mechanism. Moved from machine oil tank to condenser. By filling the inside of the condenser with refrigerating machine oil in which the refrigerant is difficult to dissolve, the amount of refrigerant that leaks from the shut-off valve and accumulates in the condenser is suppressed, and the decrease in the amount of circulating refrigerant is suppressed. As a result, the low outside air cooling operation can be stably performed. Since the refrigerant also flows into the refrigerator oil tank 10 at the time of liquid (oil) recovery, an oil separator is connected between the refrigerator oil tank 10 and the compressor 1, and the refrigerant and the refrigerator oil are separated and recovered. Needless to say, you can take it.

Modification of the first embodiment.
8 and 9 are functional block diagrams showing a configuration of a refrigeration cycle apparatus 100A according to a modification of the first embodiment. 8 and 9, the same reference numerals as those in FIG. 1 are the same as those in FIG. 1. Therefore, the description of the configurations will not be repeated below.

The refrigeration cycle apparatus 100A can perform both a cooling operation (FIG. 8) and a heating operation (FIG. 9). Hereinafter, the configuration of the refrigeration cycle apparatus 100A will be described mainly with reference to FIG. 8, and FIG. 9 will be referred to as needed.

As shown in FIG. 8, the refrigeration cycle apparatus 100A includes an outdoor unit 50A installed outdoors and an indoor unit 60A installed indoors.

The outdoor unit 50A includes a compressor 1, a four-way valve 2,

heat exchangers

31a and 31b,

fans

14a and 14b,

stop valves

6a and 6b, a refrigerator oil tank 10, a refrigerator oil moving mechanism 41, and a control. Device 15A and temperature sensor TS1 are included. The outdoor unit 50A may include three or more heat exchangers. Indoor unit 60A includes

heat exchangers

5a and 5b and

expansion valves

4a and 4b. The indoor unit 60A may include three or more heat exchangers. The refrigeration cycle apparatus 100A includes a refrigeration cycle in which refrigerant circulates in the order of the compressor 1, the four-way valve 2, the

condensers

3a and 3b, the

expansion valves

4a and 4b, and the

heat exchangers

5a and 5b.

The heat exchanger 31a is connected between the shut-off

valves

6a and 6b. The heat exchanger 31b is connected in parallel to the shutoff valve 6a, the heat exchanger 31a, and the shutoff valve 6b connected in series. The

heat exchangers

31a and 31b function as a condenser in the cooling operation, and function as an evaporator in the heating operation.

The expansion valve 4a and the heat exchanger 5a are connected in series between the heat exchanger 31a and the four-way valve 2 in this order. The expansion valve 4b and the heat exchanger 5b are connected in series in this order between the heat exchanger 31a and the four-way valve 2, and with respect to the expansion valve 4a and the heat exchanger 5a connected in series. Connected in parallel. The

heat exchangers

5a and 5b function as an evaporator in the cooling operation and function as a condenser in the heating operation.

The four-way valve 2 is controlled by the control device 15A to switch the circulation direction of the refrigerant between the circulation direction in the cooling operation and the circulation direction in the heating operation. In the cooling operation, as shown in FIG. 8, the four-way valve 2 connects the discharge port of the compressor 1 and the

heat exchangers

31a and 31b, and connects the intake port of the compressor 1 and the

heat exchangers

5a and 5b. Connecting. In the heating operation, the four-way valve 2 connects the discharge port of the compressor 1 and the

heat exchangers

5a and 5b as shown in FIG. 9, and connects the suction port of the compressor 1 and the

heat exchangers

31a and 31b. To do.

The

fans

14a and 14b are controlled by the control device 15A and send air to the

heat exchangers

31a and 31b, respectively. The amount of air blown per unit time (the number of rotations) of the

fans

14a and 14b is controlled by the control device 15A.

The control device 15A controls the opening degree of the

expansion valves

4a and 4b, and performs superheat degree control that brings the superheat degree of the gas refrigerant sucked into the compressor 1 close to the optimum value. The control device 15A controls the four-way valve 2 to switch the circulation direction of the refrigerant between the circulation direction in the cooling operation and the circulation direction in the heating operation. The control device 15A controls the air volume per unit time of the

fans

14a and 14b. When the outside air temperature T0 becomes lower than the reference temperature T1 in the cooling operation, the control device 15A controls the refrigerating machine oil moving mechanism 41 to fill the refrigerating machine oil to move the refrigerating machine oil RO from the refrigerating machine oil tank 10 to the heat exchanger 31a. Do the driving. The control device 15A controls the refrigerating machine oil recovery mechanism that controls the refrigerating machine oil moving mechanism 41 to collect the refrigerating machine oil RO from the heat exchanger 31a to the refrigerating machine oil tank 10. Since the refrigerating machine oil filling operation and the refrigerating machine oil recovery operation performed by control device 15A are the same as those in the first embodiment, description thereof will not be repeated.

When the air flow rate per unit time of the

fans

14a and 14b decreases, the efficiency of heat exchange performed between the refrigerant and the air in the

heat exchangers

31a and 31b decreases. In the cooling operation in which the

heat exchangers

31a and 31b function as condensers, the condensation capacity of the

heat exchangers

31a and 31b can be reduced by reducing the amount of air blown per unit time of the

fans

14a and 14b. it can.

Therefore, in the modified example of the first embodiment, during the low outdoor air cooling operation, first, the air flow rate per unit time of the

fans

14a and 14b may be reduced to the reference amount to suppress the reduction of the condensation pressure. Even if the air flow rate per unit time of the

fans

14a and 14b is reduced to the reference amount, if the condensing pressure is smaller than the reference pressure, the refrigerating machine oil filling operation similar to the first embodiment may be performed.

As described above, the refrigeration cycle apparatus according to the modification of the first embodiment can stably perform the low outdoor air cooling operation as in the first embodiment.

Embodiment 2. FIG.
Some refrigeration cycle apparatuses include an accumulator having a function of separating the liquid refrigerant and the gas refrigerant in order to suppress the inflow of the liquid refrigerant to the compressor. In the second embodiment, a configuration in which the accumulator is used as a refrigerating machine oil tank will be described.

The differences between the second embodiment and the first embodiment are a refrigeration oil tank, a refrigeration oil transfer mechanism, a refrigeration oil filling operation, and a refrigeration oil recovery operation. That is, FIGS. 1, 5, and 6 are replaced with FIGS. 10 to 12, respectively. Since it is the same about other points, the description will not be repeated.

FIG. 10 is a functional block diagram showing a configuration of the refrigeration cycle apparatus 200 according to the second embodiment. In the refrigerating cycle apparatus 200, the refrigerating machine oil tank 10, the refrigerating machine oil moving mechanism 41, and the control device 15 in the configuration of the refrigerating cycle apparatus 100 shown in FIG. 1 are added to the accumulator 20, the refrigerating machine oil moving mechanism 42, and the control apparatus 25. Each has been replaced.

As shown in FIG. 10, the accumulator 20 is connected between the evaporator 5 and the compressor 1. The accumulator 20 is connected to the low pressure side with respect to the refrigerant pressure. The accumulator 20 separates the refrigerant and refrigerating machine oil from the evaporator 5 into gas and liquid. When an appropriate amount of refrigerant is supplied to the refrigeration cycle apparatus 200 and the refrigeration cycle apparatus is operating normally, only a small amount of liquid refrigerant is stored in the accumulator 20. Since most of the liquid stored in the accumulator 20 becomes the refrigeration oil RO when the refrigeration cycle apparatus 200 is operating normally, the accumulator 20 can be used as a refrigeration oil tank.

The refrigerating machine oil moving mechanism 42 includes a pump 32. The pump 32 is connected between the accumulator 20 and the condenser 3a. The pump 32 moves the refrigerating machine oil RO from the accumulator 20 to the condenser 3a. In Embodiment 2, since it is necessary to move the refrigerating machine oil RO from the accumulator 20 connected to the low pressure side to the condenser 3a connected to the high pressure side, the refrigerating machine oil RO is moved against the pressure gradient. A pump 32 is required.

In the refrigerating machine oil filling operation, the

shutoff valves

6a and 6b are closed, the pump 32 is operated, and the refrigerating machine oil RO is moved from the accumulator 20 to the condenser 3a.

In the refrigerant recovery operation, the

shutoff valves

6a and 6b are opened. The refrigerating machine oil RO that has flowed out of the condenser 3 a returns to the accumulator 20 through the expansion valve 4 and the evaporator 5 and is stored.

FIG. 11 is a flowchart for explaining the flow of processing of the refrigerating machine oil filling operation in the second embodiment. As shown in FIG. 11, in S121, the control device 25 closes the closing valve 6a and the closing valve 6b and advances the process to S222. The control device 25 operates the pump 32 in S222 and advances the process to S223. In S223, the control device 25 determines whether or not the time necessary for the reference amount of the refrigerating machine oil RO to move from the accumulator 20 to the condenser 3a has elapsed. When the time necessary for the reference amount of refrigerating machine oil RO to move from accumulator 20 to condenser 3a has elapsed (YES in S223), control device 25 advances the process to S224. After stopping the pump 32 in S224, the control device 25 returns the process to the main routine. When the time required for the reference amount of the refrigerating machine oil RO to move from the accumulator 20 to the condenser 3a has not elapsed (NO in S223), the control device 25 returns the process to S223.

FIG. 12 is a flowchart for explaining the flow of processing of the refrigerating machine oil recovery operation in the second embodiment. As shown in FIG. 12, the control device 25 returns the process to the main routine after opening the closing valve 6a and the closing valve 6b in S135.

As described above, according to the refrigeration cycle apparatus according to Embodiment 2, the shutoff valve is closed to prevent the refrigerant from flowing into the condenser during the low outdoor air cooling operation, and the refrigeration oil is moved to the accumulator by the refrigeration oil moving mechanism. To the condenser. By filling the inside of the condenser with refrigerating machine oil in which the refrigerant is difficult to dissolve, the amount of refrigerant that leaks from the shut-off valve and accumulates in the condenser is suppressed, and the decrease in the amount of circulating refrigerant is suppressed. As a result, the low outside air cooling operation can be stably performed.

Furthermore, in the second embodiment, an accumulator of an existing refrigeration cycle apparatus including an accumulator can be used as a refrigeration machine oil tank. Therefore, the second embodiment can suppress the additional cost for realizing the refrigeration cycle apparatus according to the present invention rather than the first embodiment.

Embodiment 3 FIG.
Some refrigeration cycle apparatuses include an oil separator having a function of separating the refrigerant and the refrigeration oil in order to return the refrigeration oil mixed with the refrigerant from the compressor to the compressor. In Embodiment 3, a configuration in which an oil separator is used as a refrigerator oil tank will be described.

The difference between the third embodiment and the first embodiment is a refrigerating machine oil tank, a refrigerating machine oil moving mechanism, a refrigerating machine oil filling operation, and a refrigerating machine oil recovery operation. Specifically, FIG. 1, FIG. 5, and FIG. 6 replace FIG. 13, FIG. 14, and FIG. Since it is the same about other points, the description will not be repeated. Moreover, since the flow of the refrigeration oil recovery operation is the same as that of the second embodiment, the description will not be repeated.

FIG. 13 is a functional block diagram showing the configuration of the refrigeration cycle apparatus 300 according to the third embodiment. In the refrigerating cycle apparatus 300, the refrigerating machine oil tank 10, the refrigerating machine oil moving mechanism 41, and the control device 15 in the configuration of the refrigerating cycle apparatus 100 shown in FIG. 1 include the oil separator 30, the refrigerating machine oil moving mechanism 43, and the control apparatus 35. Has been replaced respectively. The refrigeration cycle apparatus 300 further includes a capillary tube 17 in addition to the configuration of the refrigeration cycle apparatus 100 shown in FIG.

As shown in FIG. 13, the oil separator 30 is connected between the compressor 1 and the condenser 3a and between the compressor 1 and the condenser 3b. The oil separator 30 is connected to the high pressure side with respect to the refrigerant pressure. The capillary tube 17 is connected between the oil separator 30 and a flow path connecting the evaporator 5 and the compressor 1.

The oil separator 30 separates and stores the refrigerating machine oil RO mixed with the refrigerant from the compressor 1. The oil separator 30 returns a part of the stored refrigerating machine oil RO to the flow path connecting the evaporator 5 and the compressor 1 via the capillary tube 17.

The refrigerating machine oil moving mechanism 43 includes a stop valve 33. The shut-off valve 33 is connected between the oil separator 30 and the condenser 3a. In Embodiment 3, since both the oil separator 30 and the condenser 3a are connected to the high pressure side, when the shut-off valve 33 is opened, the refrigeration in the oil separator 30 is caused by the pressure of the refrigerant flowing into the oil separator 30. The machine oil RO is pushed out, and the refrigerating machine oil RO moves to the condenser 3a.

In the refrigerating machine oil filling operation, the closing

valves

6a and 6b are closed, the closing valve 33 is opened, and the refrigerating machine oil RO moves from the oil separator 30 to the condenser 3a.

In the refrigerant recovery operation, the

shutoff valves

6a and 6b are opened. The refrigerating machine oil RO that has flowed out of the condenser 3 a returns to the oil separator 30 and is stored via the expansion valve 4, the evaporator 5, and the compressor 1.

FIG. 14 is a flowchart for explaining the flow of processing of the refrigerating machine oil filling operation in the third embodiment. As shown in FIG. 14, the control device 35 closes the closing valve 6a and the closing valve 6b in S121 and advances the process to S322. In S322, the control device 35 opens the shut-off valve 33 and advances the process to S323. In S323, the control device 35 determines whether or not the time necessary for the reference amount of the refrigerating machine oil RO to move from the oil separator 30 to the condenser 3a has elapsed. When the time necessary for the reference amount of the refrigerating machine oil RO to move from the oil separator 30 to the condenser 3a has elapsed (YES in S323), the process proceeds to S324. The control device 35 returns the processing to the main routine after closing the closing valve 33 in S324. If the time necessary for the reference amount of the refrigerating machine oil RO to move from the oil separator 30 to the condenser 3a has not elapsed (NO in S323), the process returns to S323.

As described above, according to the refrigeration cycle apparatus according to Embodiment 3, the shutoff valve is closed to prevent the refrigerant from flowing into the condenser during the low outside air cooling operation, and the refrigerating machine oil is transferred to the refrigerating machine oil by the refrigerating machine oil moving mechanism. Moved from separator to condenser. By filling the inside of the condenser with refrigerating machine oil in which the refrigerant is difficult to dissolve, the amount of refrigerant that leaks from the shut-off valve and accumulates in the condenser is suppressed, and the decrease in the amount of circulating refrigerant is suppressed. As a result, the low outside air cooling operation can be stably performed.

Furthermore, in Embodiment 3, the oil separator of the existing refrigeration cycle apparatus provided with an oil separator can be used as it is as a refrigerator oil tank. Therefore, the third embodiment can suppress the additional cost for realizing the refrigeration cycle apparatus according to the present invention rather than the first embodiment.

In the second and third embodiments, the control device determines whether the reference amount of the refrigeration oil RO has moved to the refrigeration oil tank or whether it has moved from the refrigeration oil tank. Although it is determined that the time has elapsed, for example, it may be determined based on a change in the amount of liquid in the refrigerating machine oil tank detected by a liquid amount sensor.

The embodiments disclosed this time are also scheduled to be implemented in appropriate combinations within a consistent range. The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 compressor, 2, 11 four-way valve, 3a, 3b condenser, 4, 4a, 4b expansion valve, 5 evaporator, 5a, 5b, 31a, 31b heat exchanger, 6a, 6b, 12, 13, 33 closing valve 10, refrigerator oil tank, 14a, 14b fan, 15, 15A, 25, 35 control device, 17 capillary tube, 20 accumulator, 30 oil separator, 32 pump, 41, 42, 43 refrigerator oil moving mechanism, 50, 50A

outdoor unit

60, 60A indoor unit, 100, 100A, 200, 300 refrigeration cycle device, RO refrigeration machine oil, TS1 temperature sensor.

Claims

The refrigerant is a refrigeration cycle apparatus in which a compressor, a first valve, a first condenser installed in the first space, a second valve, an expansion valve, and an evaporator installed in the second space are circulated in this order.
A second condenser installed in the first space;
A fluid reservoir for storing a fluid different from the refrigerant;
A liquid moving mechanism for moving the fluid from the fluid reservoir to the first condenser;
A control device for controlling the first valve, the second valve, and the liquid moving mechanism;
The second condenser is connected in parallel to the first valve, the first condenser, and the second valve connected in series;
The fluid reservoir is connected to the first condenser;
When the temperature of the first space is lower than a reference temperature, the control device moves the fluid from the fluid reservoir to the first condenser after closing the first valve and the second valve. Refrigeration cycle equipment.
The fluid reservoir is connected to the first condenser;
The liquid moving mechanism includes a flow path switching device connected to the fluid storage section, a third valve connected between the discharge port of the compressor and the flow path switching device, and an intake port of the compressor And a fourth valve connected between the flow path switching device,
The flow path switching device switches a connection state between the third valve, the fourth valve, the fluid reservoir, and the first condenser between a first connection state and a second connection state,
In the first connection state, the third valve and the fluid reservoir are connected and the fourth valve and the first condenser are connected,
In the second connection state, the third valve and the first condenser are connected and the fourth valve and the fluid reservoir are connected,
When the temperature of the first space is lower than the reference temperature, the control device closes the first valve and the second valve and controls the flow path switching device to change the connection state to the first connection. 2. The switch according to claim 1, wherein the third valve and the fourth valve are closed after a time required for the reference amount of the fluid to move from the fluid reservoir to the first condenser has elapsed. Refrigeration cycle equipment.
When the temperature of the first space is higher than the reference temperature, the control device controls the flow path switching device to switch the connection state to the second connection state, and then performs the third valve and the fourth valve. The refrigeration cycle apparatus according to claim 2, wherein the fluid in the first condenser is collected in the fluid reservoir by opening a valve.
When the user performs a stop operation of the refrigeration cycle device, the control device controls the flow path switching device to switch the connection state to the second connection state, and then the third valve and the second valve The refrigeration cycle apparatus according to claim 2, wherein the fluid in the first condenser is collected in the fluid storage unit by opening four valves.
After the time necessary for the reference amount of the fluid to move from the first condenser to the fluid reservoir has elapsed, the third valve and the fourth valve are closed, and then the first valve and the first valve are closed. The refrigeration cycle apparatus according to claim 3 or 4, wherein two valves are opened.
The fluid reservoir is connected between the evaporator and the compressor, and separates the refrigerant and the fluid from the evaporator into a gas and a liquid,
The liquid moving mechanism includes a pump that is connected between the fluid reservoir and the first condenser and moves the fluid from the fluid reservoir to the first condenser;
When the temperature of the first space is lower than the reference temperature, the control device drives the pump to move the fluid to the first condenser after closing the first valve and the second valve. The refrigeration cycle apparatus according to claim 1.
The refrigeration cycle apparatus according to claim 6, wherein the fluid storage unit includes an accumulator.
An expansion mechanism connected between the fluid reservoir and the flow path connecting the evaporator and the compressor;
The fluid reservoir is connected between the compressor and the first condenser and between the compressor and the second condenser to store and store the fluid from the compressor. Returning a part of the fluid to the flow path via the expansion mechanism;
The liquid movement mechanism includes a third valve connected between the fluid reservoir and the first condenser,
2. The refrigeration cycle apparatus according to claim 1, wherein when the temperature of the first space is lower than the reference temperature, the control device opens the third valve after closing the first valve and the second valve. .
The refrigeration cycle apparatus according to claim 8, wherein the fluid storage unit includes an oil separator.
When the temperature of the first space is higher than the reference temperature, the control device collects the fluid in the first condenser in the fluid storage unit by opening the first valve and the second valve. The refrigeration cycle apparatus according to any one of claims 6 to 9.
The control device opens the first valve and the second valve when a stop operation of the refrigeration cycle apparatus is performed by a user and the first condenser is filled with the fluid. The refrigeration cycle apparatus according to any one of claims 6 to 9.
The refrigeration cycle apparatus according to any one of claims 1 to 11, wherein the refrigerant and the fluid are incompatible.
The refrigeration cycle apparatus according to claim 12, wherein the fluid is refrigeration oil.