Refrigeration device

Abstract

This reduces the risk of refrigerant leakage into the room when high-pressure refrigerant is located on the indoor side. In the air conditioner (100), by maintaining the position of the valve core in the first position or moving it to the first position after operation stops, the refrigerant pressure in the indoor heat exchanger will decrease immediately after operation stops, even if the refrigerant pressure is high just before operation stops. Therefore, the refrigerant pressure in the indoor heat exchanger will not remain high during operation stop, thus suppressing actions that promote refrigerant leakage.

Description

Technical Field

[0001] This invention relates to a refrigeration apparatus that uses a vapor compression refrigeration cycle. Background Technology

[0002] In refrigeration devices such as air conditioners that can both cool and heat, the refrigerant circulation direction is switched between cooling and heating operation via a four-way switching valve in the refrigerant circuit. For example, the pilot-operated solenoid valve type four-way switching valve disclosed in Patent Document 1 (Japanese Patent Application Publication No. 11-294607) moves the valve core inside the four-way switching valve against the spring force when the pilot solenoid valve is energized, switching between heating and cooling operation cycles. When the pilot solenoid valve is de-energized, the valve core returns with the help of the spring force, switching between cooling and heating operation cycles. Summary of the Invention

[0003] The problem that the invention aims to solve

[0004] In recent years, various types of refrigerants have been used in the refrigerant circuits of refrigeration systems. For example, when the refrigerant circuit is filled with a slightly flammable refrigerant, a flammable refrigerant, or CO2, safety measures are required to prevent leakage into the indoor unit. Especially in the heating operation cycle where high-pressure refrigerant dissipates heat on the indoor unit side, attention must also be paid to safety after the heating operation stops.

[0005] Therefore, there is a challenge to reduce the risk of refrigerant leakage into the room when the high-pressure refrigerant is located on the indoor side.

[0006] Methods for solving problems

[0007] The first-view refrigeration device circulates refrigerant in a refrigerant circuit for refrigeration operation. The refrigerant circuit includes a compressor, a four-way switching valve, a first heat exchanger, an expansion valve, and a second heat exchanger. The four-way switching valve comprises a flow path switching valve section and a pilot valve section. The flow path switching valve section has a valve core movable between a first position and a second position different from the first position. The pilot valve section moves the valve core. The pilot valve section has a first pilot valve section and a second pilot valve section. When the valve core is in the first position, the refrigeration cycle operates as a refrigeration operation where refrigerant discharged from the compressor is delivered to the first heat exchanger via the four-way switching valve. Furthermore, when the valve core is in the second position, the refrigeration cycle operates as a heating operation where refrigerant discharged from the compressor is delivered to the second heat exchanger via the four-way switching valve. When the refrigeration cycle stops, the valve core, after stopping, remains in the first position or moves to the first position.

[0008] In this refrigeration device, by maintaining the valve core in the first position or moving it to the first position after operation stops, even if the refrigerant pressure in the second heat exchanger is high just before operation stops, it will decrease after operation stops. Therefore, the refrigerant pressure in the second heat exchanger will not remain high during operation stop, which can suppress actions that promote refrigerant leakage.

[0009] In the refrigeration device of the second viewpoint, when the valve core is in the first position, the first pilot valve section is in the open state and the second pilot valve section is in the closed state, or both the first pilot valve section and the second pilot valve section are in the closed state.

[0010] In this refrigeration device, the position of the valve core is maintained or the valve core is moved by the combination of opening and closing the first pilot valve section and the second pilot valve section, thus making control easy.

[0011] In the refrigeration device of the third viewpoint, the first pilot valve section and the second pilot valve section are electromagnetic on / off valves, and the on / off state of the on / off valve is switched by switching the energized state.

[0012] In this refrigeration device, the first pilot valve section and the second pilot valve section are switched to open or closed states by energizing or de-energizing, thus enabling the valve core to move rapidly compared to a motor-driven valve.

[0013] The fourth viewpoint's refrigeration device, compared to the third viewpoint's refrigeration device, also includes a control unit that controls the four-way switching valves. The first pilot valve and the second pilot valve are respectively closed when not energized and open when energized. When a stop command for the refrigeration cycle is issued, the control unit, after maintaining the valve core position in the first position or moving it to the first position, closes both the first and second pilot valves.

[0014] In this refrigeration device, closing the first pilot valve section and the second pilot valve section after the valve core moves makes both the first pilot valve section and the second pilot valve section non-energized, thus suppressing power consumption.

[0015] In the refrigeration device of the fifth viewpoint, when a stop command for the refrigeration cycle is issued, if the valve core is in the second position or in the third position between the first and second positions, the control unit moves the valve core to the first position.

[0016] In this refrigeration device, the control unit maintains the valve core in the first position or moves it to the first position after operation stops. As a result, even if the refrigerant pressure in the second heat exchanger is high just before operation stops, it will decrease after operation stops. Therefore, the refrigerant pressure in the second heat exchanger will not remain high during operation stop, which can suppress actions that promote refrigerant leakage.

[0017] In the refrigeration device of the sixth viewpoint, when the valve core is in the first position, the control unit opens the first pilot valve and closes the second pilot valve.

[0018] In this refrigeration device, the valve core is moved by a combination of opening and closing the first pilot valve and the second pilot valve, thus making control easy.

[0019] In the seventh viewpoint of the refrigeration device, when the valve core is in the first position and the first pilot valve is in the open state when a stop command for the refrigeration cycle is issued, the control unit closes the first pilot valve.

[0020] In this refrigeration device, closing the first pilot valve section means de-energizing the first pilot valve section. Since both the first and second pilot valve sections are de-energized, power consumption can be suppressed.

[0021] In the refrigeration device of the eighth viewpoint, when the difference between the temperature of the target space and the set temperature is within a specified range and the compressor is stopped, the control unit maintains the valve core in the first position or moves it to the first position.

[0022] In this refrigeration unit, if the temperature difference between the target space and the set temperature is within a specified range during heating operation, and the valve core remains in the second position after the compressor stops, the refrigerant pressure in the second heat exchanger remains at a high pressure. Therefore, when the compressor starts again, the refrigerant pressure in the second heat exchanger immediately rises to reach the set temperature, and the compressor stops.

[0023] The repeated starting and stopping of the compressor is the cause of the malfunction. Therefore, when the temperature difference between the air-conditioned space and the set temperature is within the specified range during heating operation, and after the compressor stops, the valve core moves to the first position to reduce the refrigerant pressure in the second heat exchanger, thereby suppressing the repeated starting and stopping of the compressor.

[0024] In the refrigeration device of the ninth viewpoint, as described in any of the second to eighth viewpoints, the flow path switching valve section further includes a high-pressure refrigerant inlet, a low-pressure refrigerant outlet, a first pilot chamber, and a second pilot chamber. The high-pressure refrigerant inlet introduces high-pressure refrigerant from the high-pressure side of the compressor. The low-pressure refrigerant outlet guides the incoming low-pressure refrigerant towards the low-pressure side of the compressor. The first pilot chamber is connected to the first pilot valve section. The second pilot chamber is connected to the second pilot valve section. When the first pilot valve section is open and the second pilot valve section is closed, the first pilot chamber is connected to the low-pressure refrigerant outlet and contracts, causing the valve core to move to a first position. When the first pilot valve section is closed and the second pilot valve section is open, the second pilot chamber is connected to the low-pressure refrigerant outlet and contracts, causing the valve core to move to a second position. Attached Figure Description

[0025] Figure 1 This is a structural diagram of an air conditioner according to one embodiment of the present invention.

[0026] Figure 2 This is a cross-sectional view of the four-way switching valve in its first state.

[0027] Figure 3 This is a cross-sectional view of the four-way switching valve during the transition from the first state to the second state.

[0028] Figure 4 This is a cross-sectional view of the four-way switching valve in its second state.

[0029] Figure 5 This is an enlarged sectional view of the valve body.

[0030] Figure 6 This is a flowchart of the valve core stop position control.

[0031] Figure 7 This is a flowchart of the thermo-off control. Detailed Implementation

[0032] (1) Structure of air conditioner 100

[0033] Figure 1 This is a structural diagram of an air conditioner 100 according to one embodiment of the present invention. Figure 1 In this air conditioner 100, the unit is a refrigeration device capable of both cooling and heating operations. It includes an indoor unit 20, an outdoor unit 10, a liquid refrigerant connecting pipe 31 for connecting the outdoor unit 10 and the indoor unit 20, and a gaseous refrigerant connecting pipe 32. CO2, as a refrigerant, is sealed in the refrigerant circuit 30 of the air conditioner 100. However, the refrigerant is not limited to CO2; other refrigerants, such as R32, can also be used.

[0034] (1-1) Indoor unit 20

[0035] The indoor unit 20 includes an indoor heat exchanger 23 and an indoor fan 24. Furthermore, the indoor unit 20 is equipped with a remote control unit 93. The remote control unit 93 communicates with the control unit 90 built into the indoor unit 20 and the outdoor unit 10 to control the air conditioner 100 according to user operation.

[0036] (1-1-1) Indoor heat exchanger 23

[0037] The indoor heat exchanger 23 is a cross-finned finned tube heat exchanger consisting of heat transfer tubes and multiple fins. During cooling operation, the indoor heat exchanger 23 functions as an evaporator for the refrigerant, cooling the indoor air; during heating operation, it functions as a condenser for the refrigerant, heating the indoor air.

[0038] The indoor heat exchanger 23 is not limited to cross-finned finned tube heat exchangers, but can also be other types of heat exchangers.

[0039] (1-1-2) Indoor fan 24

[0040] The indoor fan 24 is a cross-flow fan. The indoor fan 24 is driven by an indoor fan motor 24a. However, the indoor fan 24 is not limited to a cross-flow fan; for example, it could also be a turbine fan.

[0041] By operating the indoor fan 24, the indoor unit 20 draws in indoor air, which exchanges heat with the refrigerant in the indoor heat exchanger 23 before being supplied to the room. Furthermore, the indoor fan 24 can adjust the airflow supplied to the indoor heat exchanger 23 within a specified airflow range.

[0042] (1-2) Outdoor unit 10

[0043] exist Figure 1 The outdoor unit 10 includes a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, and an expansion valve 15. Additionally, the outdoor unit 10 also includes an outdoor fan 14.

[0044] (1-2-1) Compressor 11

[0045] Compressor 11 is a variable capacity compressor, and its speed is controlled by a frequency converter. In this embodiment, there is only one compressor 11, but it is not limited to this. Two or more compressors can be connected in parallel depending on the number of indoor units 20 connected.

[0046] (1-2-2) Four-way switching valve 12

[0047] The four-way switching valve 12 is a valve that switches the flow direction of the refrigerant. During cooling operation, the four-way switching valve 12 connects the discharge side of the compressor 11 to the gas side of the outdoor heat exchanger 13, and connects the suction side of the compressor 11 to the gas refrigerant connection piping 32. This is... Figure 1 The state shown by the solid line of the four-way switching valve 12 is called the first state. As a result, the outdoor heat exchanger 13 functions as a refrigerant condenser, and the indoor heat exchanger 23 functions as a refrigerant evaporator.

[0048] During heating operation, the four-way switching valve 12 connects the discharge side of the compressor 11 to the gas refrigerant connection piping 32, and connects the suction side of the compressor 11 to the gas side of the outdoor heat exchanger 13. This is Figure 1 The state shown by the dashed line on the four-way switching valve 12 is called the second state. As a result, the indoor heat exchanger 23 functions as a refrigerant condenser, and the outdoor heat exchanger 13 functions as a refrigerant evaporator.

[0049] (1-2-3) Outdoor heat exchanger 13

[0050] The outdoor heat exchanger 13 is a cross-finned finned tube heat exchanger. During cooling operation, the outdoor heat exchanger 13 functions as a refrigerant condenser, and during heating operation, it functions as a refrigerant evaporator. The gas side of the outdoor heat exchanger 13 is connected to the four-way switching valve 12, and its liquid side is connected to the expansion valve 15.

[0051] The outdoor heat exchanger 13 is not limited to a cross-finned finned tube heat exchanger, but can also be other types of heat exchangers.

[0052] (1-2-4) Expansion valve 15

[0053] The expansion valve 15 regulates the pressure, flow rate, and other parameters of the refrigerant flowing within the refrigerant circuit 30. The expansion valve 15 is positioned downstream of the outdoor heat exchanger 13 in the direction of refrigerant flow in the refrigerant circuit 30 during cooling operation.

[0054] (1-2-5) Outdoor fan 14

[0055] Outdoor fan 14 draws in outdoor air and directs it to outdoor heat exchanger 13 for heat exchange with refrigerant. Outdoor fan 14 can change the airflow volume when directing air to outdoor heat exchanger 13. Outdoor fan 14 is driven by outdoor fan motor 14a.

[0056] (1-3) Control Unit 90

[0057] The control unit 90 controls the operating frequency of the compressor 11, the switching action of the four-way switching valve 12, and the opening degree of the expansion valve 15 based on the command signal from the remote control unit 93.

[0058] like Figure 1 As shown, the control unit 90 includes an indoor control unit 92 built into the indoor unit 20 and an outdoor control unit 91 built into the outdoor unit 10. Infrared signals are transmitted and received between the indoor control unit 92 and the remote control unit 93. Signals are transmitted and received between the indoor control unit 92 and the outdoor control unit 91 via wires.

[0059] (2) Operation of air conditioner 100

[0060] In the air conditioner 100, the refrigerant circulation can be switched between the cooling operation cycle and the heating operation cycle via the four-way switching valve 12.

[0061] (2-1) Refrigeration operation

[0062] During refrigeration operation, the four-way switching valve 12 is set to the first state ( Figure 1 (The state of the four-way switching valve 12 is shown by the solid line). Furthermore, when the control unit 90 runs the compressor 11 in this state, a vapor compression refrigeration cycle is performed, in which the outdoor heat exchanger 13 becomes the condenser and the indoor heat exchanger 23 becomes the evaporator.

[0063] The high-pressure refrigerant discharged from compressor 11 condenses in the outdoor heat exchanger 13 by exchanging heat with outdoor air. The refrigerant flowing out of the outdoor heat exchanger 13 is depressurized as it passes through expansion valve 15, and then evaporates by exchanging heat with indoor air in the indoor heat exchanger 23. At this time, the air is cooled by the indoor heat exchanger 23, and this cooled air is blown into the room from indoor unit 20 via indoor fan 24. The refrigerant flowing out of indoor heat exchanger 23 is drawn into compressor 11 and compressed.

[0064] (2-2) Heating Operation

[0065] During heating operation, the four-way switching valve 12 is set to the second state ( Figure 1 (The state is shown by the dashed line of the four-way switching valve 12). Furthermore, when the control unit 90 runs the compressor 11 in this state, a vapor compression refrigeration cycle is performed, in which the outdoor heat exchanger 13 becomes the evaporator and the indoor heat exchanger 23 becomes the condenser.

[0066] The high-pressure refrigerant discharged from compressor 11 condenses in the indoor heat exchanger 23 by exchanging heat with indoor air. At this time, the air is heated by the indoor heat exchanger 23, and the heated air is blown into the room from indoor unit 20 via indoor fan 24. The condensed refrigerant is depressurized as it passes through expansion valve 15, and then evaporates by exchanging heat with outdoor air in outdoor heat exchanger 13. The refrigerant flowing out of outdoor heat exchanger 13 is drawn into compressor 11 and compressed.

[0067] (3) Structure of the four-way switching valve 12

[0068] Figure 2 yes Figure 1 A cross-sectional view of the four-way switching valve 12 in the first state shown by the solid line. Figure 3 yes Figure 1 A cross-sectional view of the four-way switching valve 12 during its transition from the first state (shown by the solid line) to the second state (shown by the dashed line). Figure 4 yes Figure 1 A cross-sectional view of the four-way switching valve 12 in the second state shown by the dashed line. Figure 2 , Figure 3 as well as Figure 4 In the middle, the four-way switching valve 12 includes a flow path switching valve section 50, a pilot valve section 60, and capillary tubes 81a~81c connecting the flow path switching valve section 50 and the pilot valve section 60.

[0069] (3-1) Flow path switching valve section 50

[0070] The flow path switching valve section 50 includes a cylinder body 51, a valve core 52, a first piston 53a, a second piston 53b, a piston rod 54, a first pilot chamber 55a, and a second pilot chamber 55b.

[0071] (3-1-1) Cylinder block 51

[0072] The cylinder body 51 is a cylindrical metal component whose two ends are sealed by a first bolt 511 and a second bolt 512. Figure 2 , Figure 3 as well as Figure 4 In the main view, the first bolt 511 blocks the left end of the cylinder body 51, and the second bolt 512 blocks the right end of the cylinder body 51. A through hole 511a is provided in the first bolt 511. A through hole 512a is provided in the second bolt 512.

[0073] The side wall of the cylinder 51 is provided with a first flow path Pa, a second flow path Pb, a third flow path Pc and a fourth flow path Pd that connect the interior of the cylinder 51 with the refrigerant circuit 30.

[0074] The first flow path Pa is located at the center of the side wall of the cylinder 51 and is connected to the discharge pipe of the compressor 11. The second flow path Pb is located opposite the first flow path Pa and is connected to the suction pipe of the compressor 11.

[0075] The third flow path Pc and the fourth flow path Pd are arranged axially in the cylinder block 51, separated from the second flow path Pb. The third flow path Pc is connected to the outdoor heat exchanger 13, and the fourth flow path Pd is connected to the indoor heat exchanger 23.

[0076] The interior of the cylinder body 51 becomes a cavity 510 communicating with the first flow path Pa, the second flow path Pb, the third flow path Pc, and the fourth flow path Pd. The open ends of the second flow path Pb, the third flow path Pc, and the fourth flow path Pd on the side near the cavity 510 form valve seats 56 with flat sliding surfaces.

[0077] (3-1-2) Valve core 52

[0078] The valve core 52 slides in contact with the sliding surface of the valve seat 56. The valve core 52 has a length in the sliding direction that covers the length of two adjacent openings in each of the openings of the second flow path Pb, the third flow path Pc, and the fourth flow path Pd. Furthermore, the valve core 52 has a recess 52a on the side facing the sliding surface of the valve seat 56 that connects the two openings to be covered.

[0079] (3-1-2-1) First position of valve core 52

[0080] exist Figure 2 In this configuration, valve core 52 is positioned to connect the openings of the second flow path Pb and the fourth flow path Pd; this position is referred to as the first position. When valve core 52 is in the first position, the refrigeration cycle operates in refrigeration mode. The high-pressure gaseous refrigerant discharged from compressor 11 flows into cylinder 51 through the first flow path Pa, flows through the third flow path Pc to the outdoor heat exchanger 13 where it condenses, is depressurized in expansion valve 15, evaporates in indoor heat exchanger 23, and is drawn into compressor 11 through the second flow path Pb from the fourth flow path Pd.

[0081] (3-1-2-2) Second position of valve core 52

[0082] exist Figure 4 In this configuration, valve core 52 is positioned to connect the openings of the second flow path Pb and the third flow path Pc; this position is referred to as the second position. When valve core 52 is in the second position, the refrigeration cycle operates in heating mode. The high-pressure gaseous refrigerant discharged from compressor 11 flows into cylinder 51 through the first flow path Pa, flows through the fourth flow path Pd to the indoor heat exchanger 23 where it condenses, is depressurized in expansion valve 15, evaporates in outdoor heat exchanger 13, and is drawn into compressor 11 through the third flow path Pc and the second flow path Pb.

[0083] (3-1-2-3) Third position of valve core 52

[0084] exist Figure 3 In this configuration, valve core 52 is located between the first position and the second position. This position is referred to as the third position. The third position is the position reached by valve core 52 gradually moving from the first or second position.

[0085] Alternatively, it could be in the following position: if the power is cut off during operation switching, or while the valve core 52 is moving from the first position to the second position or from the second position to the first position, the valve core 52 stops before reaching either the first or the second position.

[0086] (3-1-3) First piston 53a, second piston 53b and piston rod 54

[0087] In the cavity 510 of the cylinder 51, a first piston 53a and a second piston 53b connected by a piston rod 54 are slidably disposed.

[0088] exist Figure 2 , Figure 3 as well as Figure 4 In the main view, the first piston 53a is located between the first plug 511 and the fourth flow path Pd. The first piston 53a has a small hole 531 that extends through the axis.

[0089] exist Figure 2 , Figure 3 as well as Figure 4 In the main view, the second piston 53b is located between the second plug 512 and the third flow path Pc. The second piston 53b has a small hole 532 that extends axially.

[0090] The piston rod 54 holds the valve core 52 and moves together with the first piston 53a and the second piston 53b.

[0091] (3-1-4) First pilot room 55a and second pilot room 55b

[0092] The first pilot chamber 55a is the space between the first bolt 511 and the first piston 53a. The second pilot chamber 55b is the space between the second bolt 512 and the second piston 53b.

[0093] A portion of the high-pressure refrigerant flowing in from the first flow path Pa flows into the first pilot chamber 55a through the orifice 531 of the first piston 53a, and into the second pilot chamber 55b through the orifice 532 of the second piston 53b.

[0094] When there is a pressure difference between the first pilot chamber 55a and the second pilot chamber 55b, the first piston 53a, the second piston 53b, the piston rod 54, and the valve core 52 move.

[0095] For example, in Figure 2 In the first pilot chamber 55a, the pressure is less than the pressure in the second pilot chamber 55b. Therefore, the first piston 53a, the second piston 53b, the piston rod 54, and the valve core 52 are in... Figure 2 When the main view is moved to the left, the valve core 52 is in the first position.

[0096] In addition, Figure 4 In the process, because the pressure in the first pilot chamber 55a is greater than the pressure in the second pilot chamber 55b, the first piston 53a, the second piston 53b, the piston rod 54, and the valve core 52 are in... Figure 4 When the main view is turned to the right, the valve core 52 is in the second position.

[0097] (3-2) Pilot valve section 60

[0098] The pilot valve section 60 has a first pilot valve section 60a and a second pilot valve section 60b.

[0099] (3-2-1) First pilot valve section 60a

[0100] The first pilot valve section 60a includes a valve body 61, a first valve seat 61a, a first valve chamber 62a, a first plunger 63a, a first solenoid 64a, and a first helical spring 65a.

[0101] The valve body 61 is shared with the second pilot valve section 60b. The first valve seat 61a is formed inside the valve body 61. The first valve chamber 62a is a space for the first plunger 63a to move and communicates with the opening of the first valve seat 61a.

[0102] The first plunger 63a moves within the first valve chamber 62a to open and close the opening of the first valve seat 61a. When the first solenoid 64a is energized, an electromagnetic force is generated, causing the first plunger 63a to move away from the opening of the first valve seat 61a. The first helical spring 65a constantly presses the first plunger 63a toward closing the opening of the first valve seat 61a.

[0103] Because the electromagnetic force of the first solenoid 64a is greater than the force of the first helical spring 65a pressing the first plunger 63a, the opening of the first valve seat 61a opens when the first solenoid 64a is energized. When the first solenoid 64a is not energized, the first helical spring 65a presses the first plunger 63a, thus closing the opening of the first valve seat 61a.

[0104] (3-2-2) Second pilot valve section 60b

[0105] The second pilot valve section 60b includes a valve body 61, a second valve seat 61b, a second valve chamber 62b, a second plunger 63b, a second solenoid 64b, and a second helical spring 65b.

[0106] The valve body 61 is shared with the first pilot valve section 60a. The second valve seat 61b is formed inside the valve body 61. The second valve chamber 62b is a space for the movement of the second plunger 63b and communicates with the opening of the second valve seat 61b.

[0107] The second plunger 63b moves within the second valve chamber 62b to open and close the opening of the second valve seat 61b. When the second solenoid 64b is energized, an electromagnetic force is generated, causing the second plunger 63b to move away from the opening of the second valve seat 61b. The second helical spring 65b constantly presses the second plunger 63b towards closing the opening of the second valve seat 61b.

[0108] Because the electromagnetic force of the second solenoid 64b is greater than the force exerted by the second helical spring 65b on the second plunger 63b, the opening of the second valve seat 61b opens when the second solenoid 64b is energized. When the second solenoid 64b is not energized, the second helical spring 65b presses down on the second plunger 63b, thus closing the opening of the second valve seat 61b.

[0109] (3-2-3) Structure of valve body 61

[0110] Figure 5 This is an enlarged sectional view of the valve body 61. Figure 5 In the valve body 61, the openings of the first valve seat 61a and the second valve seat 61b are connected through the first connecting hole 611. Furthermore, the valve body 61 is provided with a second connecting hole 612, a third connecting hole 613, and a fourth connecting hole 614.

[0111] The second connecting hole 612 is connected to the first connecting hole 611. Furthermore, as... Figure 2 , Figure 3 as well as Figure 4 As shown, the second connecting hole 612 is connected to the second flow path Pb of the flow path switching valve section 50 via the capillary tube 81c.

[0112] The third connecting hole 613 is connected to the first valve chamber 62a. Furthermore, as... Figure 2 , Figure 3 and Figure 4 As shown, the third connecting hole 613 is connected to the first pilot chamber 55a of the flow path switching valve section 50 via the capillary tube 81a.

[0113] The fourth connecting hole 614 is connected to the second valve chamber 62b. Furthermore, as... Figure 2 , Figure 3 and Figure 4 As shown, the fourth connecting hole 614 is connected to the second pilot chamber 55b of the flow path switching valve section 50 via the capillary tube 81b.

[0114] (4) Operation of the four-way switching valve 12

[0115] The four-way switching valve 12 switches the position of the valve core 52 of the flow path switching valve section 50 to the first position or the second position by switching the opening and closing of the first pilot valve section 60a and the second pilot valve section 60b.

[0116] The following explanation assumes that when the first pilot valve 60a is energized and becomes open, the second pilot valve 60b is de-energized and becomes closed, and when the first pilot valve 60a is de-energized and becomes closed, the second pilot valve 60b is energized and becomes open.

[0117] (4-1) Case where the first pilot valve section 60a is open and the second pilot valve section is closed

[0118] exist Figure 2 and Figure 5 When the first solenoid 64a is energized, the first plunger 63a overcomes the spring force of the first helical spring 65a by means of the electromagnetic force of the first solenoid 64a and leaves the opening of the first valve seat 61a. Therefore, the opening of the first valve seat 61a opens, the first valve chamber 62a connects with the third connecting hole 613, and the refrigerant flows from the first pilot chamber 55a of the flow path switching valve section 50 through the capillary tubes 81a and 81c to the second flow path Pb, and the first pilot chamber 55a is transferred to low pressure.

[0119] On the other hand, since the second solenoid 64b is not energized, the second plunger 63b is pressed by the second helical spring 65b in the direction of closing the second valve seat 61b. Therefore, the second plunger 63b cuts off the communication between the second valve chamber 62b and the fourth connecting hole 614, so the refrigerant will not flow from the second pilot chamber 55b of the flow path switching valve section 50 to the second flow path Pb, and the second pilot chamber 55b maintains high pressure.

[0120] As a result, the first piston 53a, the second piston 53b, the piston rod 54, and the valve core 52 move in the direction that reduces the space of the first pilot chamber 55a, and the valve core 52 reaches the first position. At this time, the first flow path Pa is connected to the third flow path Pc, and the high-pressure gaseous refrigerant from the compressor 11 flows to the outdoor heat exchanger 13. The second flow path Pb is connected to the fourth flow path Pd, and the low-pressure refrigerant from the indoor heat exchanger 23 is drawn into the compressor 11.

[0121] (4-2) Case where the first pilot valve section 60a is closed and the second pilot valve section is open

[0122] exist Figure 4 and Figure 5When the second solenoid 64b is energized, the second plunger 63b overcomes the spring force of the second helical spring 65b by means of the electromagnetic force of the second solenoid 64b and leaves the opening of the second valve seat 61b. Therefore, the opening of the second valve seat 61b opens, the second valve chamber 62b connects with the fourth connecting hole 614, and the refrigerant flows from the second pilot chamber 55b of the flow path switching valve section 50 through the capillary tubes 81b and 81c to the second flow path Pb, and the second pilot chamber 55b is transferred to low pressure.

[0123] On the other hand, since the first solenoid 64a is not energized, the first plunger 63a is pressed by the first helical spring 65a in the direction of closing the first valve seat 61a. Therefore, the first plunger 63a cuts off the communication between the first valve chamber 62a and the third connecting hole 613, so the refrigerant will not flow from the first pilot chamber 55a of the flow path switching valve section 50 to the second flow path Pb, and the first pilot chamber 55a maintains high pressure.

[0124] As a result, the first piston 53a, the second piston 53b, the piston rod 54, and the valve core 52 move in the direction that reduces the space of the second pilot chamber 55b, and the valve core 52 reaches the second position. At this time, the first flow path Pa is connected to the fourth flow path Pd, and the high-pressure gaseous refrigerant from the compressor 11 flows to the indoor heat exchanger 23. The second flow path Pb is connected to the third flow path Pc, and the low-pressure refrigerant from the outdoor heat exchanger 13 is drawn into the compressor 11.

[0125] (5) Stop position control of valve core 52 in four-way switching valve 12

[0126] When the refrigerant circuit 30 is filled with CO2, a slightly flammable refrigerant, or a flammable refrigerant, safety measures are needed to prevent leakage into the room. In this embodiment, when the air conditioner 100 stops during heating operation with high-pressure refrigerant on the indoor side, the valve core 52 is moved to the first position to reduce the risk of refrigerant leakage into the room, thereby reducing the pressure.

[0127] Figure 6 This is a flowchart of the stop position control of valve core 52. The stop position control of valve core 52 will be explained below with reference to the accompanying drawings.

[0128] (Step S1)

[0129] In step S1, the control unit 90 determines whether there is an operation stop command from the air conditioner 100. If there is an operation stop command, it proceeds to step S2.

[0130] (Step S2)

[0131] In step S2, the control unit 90 stops the air conditioner 100 and proceeds to step S3.

[0132] (Step S3)

[0133] In step S3, the control unit 90 determines whether the air conditioner 100 has stopped operating in heating mode. If the control unit 90 determines that the air conditioner 100 has stopped operating in heating mode, it proceeds to step S4. Furthermore, if the control unit 90 determines that the air conditioner 100 has not stopped operating in heating mode, it proceeds to step S5.

[0134] (Step S4)

[0135] In step S4, the control unit 90 moves the valve core 52 of the four-way switching valve 12 to the first position. When the air conditioner 100 stops operating in heating mode, the valve core 52 of the four-way switching valve 12 is in the second position. Therefore, if the position of the valve core 52 is moved from the second position to the first position beforehand, even if the refrigerant pressure in the indoor heat exchanger 23 is high before operation stops, it will decrease after operation stops. As a result, the refrigerant pressure in the indoor heat exchanger 23 will not remain high during operation stoppage, thus suppressing actions that promote refrigerant leakage.

[0136] Here, "before operation is about to stop" means just before receiving an operation stop command. Furthermore, "operation stop" means at least the compressor 11 has stopped.

[0137] Furthermore, the process of "moving the valve core 52 to the first position" in step S4 is specifically a process of "opening the first pilot valve section 60a and closing the second pilot valve section 60b". As a result, the valve core 52 moves to the first position.

[0138] Furthermore, the aforementioned process of "opening the first pilot valve section 60a and closing the second pilot valve section 60b" specifically refers to the process of "energizing the first pilot valve section 60a but not energizing the second pilot valve section 60b." In this case, the first solenoid 64a is energized, the first plunger 63a is disengaged from the first valve seat 61a by electromagnetic force, and the first pilot chamber 55a of the flow path switching valve section 50 is connected to the second flow path Pb. As a result, the first pilot chamber 55a shrinks, and the valve core 52 moves to the first position.

[0139] On the other hand, since no electromagnetic force is generated in the second solenoid 64b, the second valve seat 61b is closed by the second plunger 63b.

[0140] Preferably, after the process of "energizing the first pilot valve section 60a but not the second pilot valve section 60b" described above, the energization of the first pilot valve section 60a and the second pilot valve section 60b is stopped. This is because even if the energization is stopped, the position of the valve core 52 remains in the first position, thereby suppressing unnecessary power consumption.

[0141] (Step S5)

[0142] In step S5, the control unit 90 maintains the valve core 52 of the four-way switching valve 12 in the first position. When the air conditioner 100 stops operating in a mode other than heating, it is assumed that the cooling operation or refrigerant circulation has stopped during the defrosting operation, which is the same as the cooling operation. Therefore, the valve core 52 of the four-way switching valve 12 is in the first position. Thus, it is sufficient to maintain the position of the valve core 52 in the first position.

[0143] Furthermore, the process of "maintaining the position of valve core 52 in the first position" in step S5 specifically means "opening the first pilot valve section 60a, closing the second pilot valve section 60b, or closing both the first pilot valve section 60a and the second pilot valve section 60b." Thus, valve core 52 is set and maintained in the first position.

[0144] Furthermore, the aforementioned process of "opening the first pilot valve 60a and closing the second pilot valve 60b, or closing both the first pilot valve 60a and the second pilot valve 60b" specifically means "energizing the first pilot valve 60a but not the second pilot valve 60b, or not energizing either the first pilot valve 60a or the second pilot valve 60b." For ease of explanation, the former will be referred to as process A and process B.

[0145] As in case A, when the first pilot valve section 60a is energized but the second pilot valve section 60b is not, the first solenoid 64a is energized, and the first plunger 63a moves away from the first valve seat 61a by electromagnetic force, connecting the first pilot chamber 55a of the flow path switching valve section 50 to the second flow path Pb. As a result, the first pilot chamber 55a shrinks, and the valve core 52 moves to the first position. On the other hand, when the second solenoid 64b does not generate electromagnetic force, the second valve seat 61b is closed by the second plunger 63b.

[0146] The advantage of handling A is that, for example, when the operation stops at the moment of switching from defrosting operation to heating operation and the valve core 52 stops between the first position and the second position, the valve core 52 can be reliably moved to the first position.

[0147] On the other hand, as in case B, when neither the first pilot valve section 60a nor the second pilot valve section 60b is energized, no electromagnetic force is generated in the first solenoid 64a and the second solenoid 64b. The first valve seat 61a is closed by the first plunger 63a, and the second valve seat 61b is closed by the second plunger 63b. As a result, the pressure difference between the first pilot chamber 55a and the second pilot chamber 55b of the flow path switching valve section 50 is maintained, and therefore, the position of the valve core 52 is also maintained in the first position.

[0148] Energizing the first pilot valve 60a to maintain its open state after operation stops would waste power. Therefore, it is reasonable to avoid energizing the first pilot valve 60a after operation stops.

[0149] Therefore, it is preferable to maintain the valve core 52 in the first position by process B after setting the valve core 52 in the first position by process A.

[0150] In addition, as a supplement to the control of the stop position of valve core 52, Figure 6 Step S2 can also be executed after the processing of steps S4 and S5.

[0151] In this case, step S3 does not determine whether the operation has stopped during heating, but rather determines whether the operation at the time the operation stop command was received in step S1 was a heating operation.

[0152] (6) Variations

[0153] In the above embodiment, the first pilot valve 60a opens when energized and closes when not energized, and the second pilot valve 60b also opens when energized and closes when not energized. However, it is not limited to this, and it may also be configured such that the first pilot valve 60a closes when energized and opens when not energized, and the second pilot valve 60b also closes when energized and opens when not energized.

[0154] (7) Characteristics

[0155] (7-1)

[0156] In the air conditioner 100, by maintaining the position of the valve core in the first position or moving it to the first position after the operation stops, even if the refrigerant pressure in the indoor heat exchanger is high before the operation stops, it will decrease after the operation stops. Therefore, the refrigerant pressure in the indoor heat exchanger will not remain high during operation stop, which can suppress actions that promote refrigerant leakage.

[0157] (7-2)

[0158] In the air conditioner 100, when the valve core 52 is in the first position, the first pilot valve section 60a is in the open state and the second pilot valve section 60b is in the closed state, or both the first pilot valve section 60a and the second pilot valve section 60b are in the closed state. By combining the opening and closing of the first pilot valve section 60a and the second pilot valve section 60b, the position of the valve core 52 is maintained or the valve core 52 is moved, thus making control easy.

[0159] (7-3)

[0160] In the air conditioner 100, the opening and closing states of the first pilot valve section 60a and the second pilot valve section 60b can be switched by whether they are powered on or off, thus enabling the valve core to move quickly compared to a motor-driven valve.

[0161] (7-4)

[0162] In the air conditioner 100, when the valve core 52 moves, the first pilot valve section 60a and the second pilot valve section 60b are closed, which means that the first pilot valve section 60a and the second pilot valve section 60b are de-energized, thereby suppressing power consumption.

[0163] (7-5)

[0164] In the air conditioner 100, when a stop command for the refrigeration cycle is issued and the operation is in heating mode with the valve core 52 in the second position or a third position between the first and second positions, the control unit 90 moves the valve core 52 towards the first position. As a result, even if the refrigerant pressure in the second heat exchanger is high just before operation stops, it will decrease immediately after operation stops. Therefore, during operation stoppage, the refrigerant pressure in the second heat exchanger will not remain high, thus suppressing actions that promote refrigerant leakage.

[0165] (7-6)

[0166] In the air conditioner 100, when the valve core 52 is in the first position, the control unit 90 opens the first pilot valve 60a and closes the second pilot valve 60b. The valve core 52 is moved by a combination of opening and closing the first pilot valve 60a and the second pilot valve 60b, thus facilitating control.

[0167] (7-7)

[0168] In the air conditioner 100, when the valve core 52 is in the first position and the first pilot valve 60a is in the open state when a stop command for the refrigeration cycle is issued, the control unit 90 closes the first pilot valve 60a. Closing the first pilot valve 60a means de-energizing it. Since both the first and second pilot valves 60a are de-energized, power consumption is suppressed.

[0169] (7-8)

[0170] When the first pilot chamber 55a of the four-way switching valve 12 is in the open state and the second pilot valve section 60a is in the closed state, it is connected to the second flow path Pb and shrinks, causing the valve core 52 to move to the first position. When the second pilot chamber 55b of the four-way switching valve 12 is in the closed state and the second pilot valve section 60b is in the open state, it is connected to the second flow path Pb and shrinks, causing the valve core 52 to move to the second position.

[0171] (8) Other implementation methods

[0172] When the air conditioner 100 is a paired unit where an outdoor unit 10 is connected to an indoor unit 20, the stop position control of the valve core 52 is not limited to when the operation stops due to a power outage. For example, the stop position control of the valve core 52 is also performed when the compressor stops due to a temperature control shutdown, where the difference between the indoor set temperature and the indoor temperature is within a specified range.

[0173] Figure 7 This is a flowchart of the temperature control shutdown process. Here, as an example, please refer to... Figure 7 The stop position control of the valve core 52 in other embodiments will be described.

[0174] (Step S11)

[0175] In step S11, the control unit 90 obtains the indoor set temperature Ts as the set temperature of the air-conditioned space, i.e., the indoor space. The indoor set temperature Ts is set by the user via the remote control unit 93.

[0176] (Step S12)

[0177] In step S12, the control unit 90 detects the indoor temperature Tr via the indoor temperature sensor 95. The indoor temperature sensor 95 is disposed in the indoor unit 20.

[0178] (Step S13)

[0179] In step S13, the control unit 90 determines whether the absolute value of the difference between the indoor set temperature Ts and the indoor temperature Tr is below a predetermined value X. If the control unit 90 determines that the absolute value of the difference between the indoor set temperature Ts and the indoor temperature Tr is below the predetermined value X, it proceeds to step S14. On the other hand, if the control unit 90 determines that the absolute value of the difference between the indoor set temperature Ts and the indoor temperature Tr is not below the predetermined value X, it returns to step S11.

[0180] (Step S14)

[0181] In step S14, the control unit 90 stops the compressor 11 and enters... Figure 6 Step S3 is shown.

[0182] (Step S3)

[0183] In step S3, the control unit 90 determines whether the air conditioner 100 has stopped operating in heating mode. If the control unit 90 determines that the air conditioner 100 has stopped operating in heating mode, it proceeds to step S4. Furthermore, if the control unit 90 determines that the air conditioner 100 has not stopped operating in heating mode, it proceeds to step S5.

[0184] (Step S4)

[0185] In step S4, the control unit 90 moves the valve core 52 of the four-way switching valve 12 to the first position. Specifically, to move the valve core 52 to the first position, the first pilot valve 60a is opened and the second pilot valve 60b is closed. As a result, the valve core 52 moves to the first position.

[0186] (Step S5)

[0187] In step S5, the control unit 90 maintains the valve core 52 of the four-way switching valve 12 in a first position. Specifically, to maintain the valve core 52 in the first position, the first pilot valve 60a is opened and the second pilot valve 60b is closed, or both the first pilot valve 60a and the second pilot valve 60b are closed. Thus, the valve core 52 is set and maintained in the first position.

[0188] If the valve core 52 is positioned in the first position before heating operation stops, the refrigerant pressure in the indoor heat exchanger 23 will decrease immediately after operation stops, even if the refrigerant pressure was high just before operation stopped. As a result, the refrigerant pressure in the indoor heat exchanger 23 will not remain high during operation stoppage, thus suppressing actions that promote refrigerant leakage.

[0189] Furthermore, when the compressor 11 is stopped, by maintaining or moving the valve core 52 to the first position, the refrigerant pressure in the indoor heat exchanger 23 is reduced, which can suppress the phenomenon of "the indoor heat exchanger 23 immediately becoming high pressure and the compressor 11 repeatedly starting and stopping," i.e., the oscillation phenomenon.

[0190] In addition, the control unit 90 can also pre-store the number of times the compressor 11 starts and stops every specified time during heating operation. If the number of times the compressor 11 starts and stops every specified time is more than the specified number when the temperature control is turned off, the valve core 52 is moved to the first position for control.

[0191] Furthermore, when the air conditioning load exceeds the specified load, it is difficult to assume that the compressor 11 is repeatedly starting and stopping. Therefore, it can also be controlled by keeping the valve core 52 in the second position during heating operation.

[0192] The embodiments of this disclosure have been described above, but it should be understood that various changes in manner and details can be made without departing from the spirit and scope of this disclosure as set forth in the claims.

[0193] Label Explanation

[0194] 11 compressors

[0195] 12 four-way switching valve

[0196] 13 Outdoor heat exchangers (first heat exchanger)

[0197] 15 Expansion Valve

[0198] 23. Indoor heat exchanger (second heat exchanger)

[0199] 30 Refrigerant Circuit

[0200] 50 Flow path switching valve section

[0201] 52 valve core

[0202] 55a First Pilot Room

[0203] 55b Second Pilot Room

[0204] 60 pilot valve section

[0205] 60a First Pilot Valve Section

[0206] 60b Second Pilot Valve Section

[0207] 90 Control Department

[0208] 100 Air Conditioner (Refrigeration Unit)

[0209] Pa First Flow Path (High-Pressure Refrigerant Inflow Section)

[0210] Pb second flow path (low-pressure refrigerant inlet section)

[0211] PC third flow path

[0212] Pd fourth flow path

[0213] Existing technical documents

[0214] Patent documents

[0215] Patent Document 1: Japanese Patent Application Publication No. 11-294607

Claims

1. A refrigeration device (100) in which a refrigerant circulates in a refrigerant circuit (30) to perform a refrigeration cycle, wherein the refrigerant circuit (30) includes a compressor (11), a four-way switching valve (12), a first heat exchanger (13), an expansion valve (15), and a second heat exchanger (23), wherein, The four-way switching valve (12) has the following features: A flow path switching valve section (50) has a valve core (52) movable between a first position and a second position different from the first position; and The pilot valve section (60) moves the valve core (52). The pilot valve section (60) has a first pilot valve section (60a) and a second pilot valve section (60b). When the valve core (52) is in the first position, the refrigeration cycle operates as a refrigeration cycle in which the refrigerant discharged from the compressor (11) is delivered to the first heat exchanger (13) via the four-way switching valve (12). When the valve core (52) is in the second position, the refrigeration cycle operates as a heating cycle in which the refrigerant discharged from the compressor (11) is delivered to the second heat exchanger (23) via the four-way switching valve (12). When the refrigeration cycle stops, the valve core (52) remains in the first position or moves to the first position after the operation stops.

2. The refrigeration device (100) according to claim 1, wherein, When the valve core (52) is in the first position, The first pilot valve section (60a) is in the open state and the second pilot valve section (60b) is in the closed state, or, Both the first pilot valve section (60a) and the second pilot valve section (60b) are in the closed state.

3. The refrigeration device (100) according to claim 1 or 2, wherein, The first pilot valve (60a) and the second pilot valve (60b) are electromagnetic on / off valves, and the on / off state of the valves is switched by switching the energized state.

4. The refrigeration device (100) according to claim 3, wherein, The refrigeration device (100) also includes a control unit (90) for controlling the four-way switching valve (12). The first pilot valve section (60a) and the second pilot valve section (60b) are respectively in a closed state when not energized and in an open state when energized. When a stop command for the operation of the refrigeration cycle is issued, the control unit (90) maintains the position of the valve core (52) at the first position or moves it to the first position, and then closes the first pilot valve (60a) and the second pilot valve (60b).

5. The refrigeration device (100) according to claim 4, wherein, When a stop command for the operation of the refrigeration cycle is issued, if the valve core (52) is in the second position or in the third position between the first position and the second position, the control unit (90) moves the valve core (52) toward the first position.

6. The refrigeration apparatus (100) according to claim 4 or 5, wherein, When the valve core (52) is in the first position, the control unit (90) opens the first pilot valve (60a) and closes the second pilot valve (60b).

7. The refrigeration device (100) according to claim 4, wherein, When the valve core (52) is in the first position and the first pilot valve (60a) is in the open state when the stop command for the operation of the refrigeration cycle is issued, the control unit (90) closes the first pilot valve (60a).

8. The refrigeration device (100) according to claim 4, wherein, When the difference between the temperature of the air-conditioned space and the set temperature is within a specified range and the compressor (11) is stopped, the control unit (90) keeps the valve core (52) in the first position or moves it to the first position.

9. The refrigeration apparatus (100) according to any one of claims 2 to 8, wherein, The flow path switching valve section (50) also has: High-pressure refrigerant inlet (Pa) introduces high-pressure refrigerant from the high-pressure side of the compressor (11); The low-pressure refrigerant outlet (Pb) guides the incoming low-pressure refrigerant toward the low-pressure side of the compressor (11); The first pilot chamber (55a) is connected to the first pilot valve section (60a); and The second pilot chamber (55b) is connected to the second pilot valve section (60b). When the first pilot chamber (55a) is in the open state and the second pilot valve section (60a) is in the closed state, it is connected to the low-pressure refrigerant outlet (Pb) and thus narrows, causing the valve core (52) to move to the first position. When the first pilot valve section (60a) is in the closed state and the second pilot valve section (60b) is in the open state, the second pilot chamber (55b) is connected to the low-pressure refrigerant outlet (Pb) and shrinks, causing the valve core (52) to move to the second position.

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