Refrigerator

Abstract

To shorten the time until a start of a heating operation from when a command of the heating operation is received again after stopping the heating operation.SOLUTION: If a heating operation or a defrost operation in which a coolant in a refrigerant in a refrigerant circuit circulates in the same direction as in a cooling operation proceeds immediately before a refrigeration cycle operation is stopped in an air conditioner 100, a position of a valve body 52 after a non-operation is maintained at a second position, or is moved to the second position. As a result, it is possible to shorten the time until the start of the heating operation from a non-operation state.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] This invention relates to a refrigeration system using a vapor compression refrigeration cycle. [Background technology]

[0002] In refrigeration equipment such as a heating and cooling air conditioner, the direction of refrigerant circulation is switched between cooling and heating operation via a four-way selector valve in the refrigerant circuit. For example, in a pilot solenoid valve type four-way selector valve disclosed in Patent Document 1 (Japanese Utility Model Publication No. 55-53825), when the pilot solenoid valve is in an energized state, the valve element inside the four-way selector valve moves against spring force to switch to the heating operation cycle, and when the pilot solenoid valve is in a de-energized state, the valve element returns due to spring force to switch to the cooling operation cycle. Summary of the Invention [Problem to be solved by the invention]

[0003] However, with the above configuration, even in winter when heating operation is performed, when the air conditioner stops operating, the valve body inside the four-way switching valve moves and waits in the cooling operation cycle position, so it takes time from receiving a heating operation command to starting heating operation.

[0004] Therefore, there is a need to shorten the time from receiving a command to start the heating operation to the start of the heating operation. [Means for solving the problem]

[0005] A refrigeration apparatus according to a first aspect is a refrigeration apparatus in which a refrigerant circulates through a refrigerant circuit including a compressor, a four-way switching valve, a first heat exchanger, an expansion valve, and a second heat exchanger, and a refrigeration cycle operation is performed, the four-way switching valve including a flow path switching valve unit and a pilot valve unit. The flow path switching valve unit has a valve element movable between a first position and a second position different from the first position. The pilot valve unit moves the valve element. When the valve element is in the first position, the refrigeration cycle operation is a cooling operation in which refrigerant discharged from the compressor is sent to the first heat exchanger via the four-way switching valve. When the valve element is in the second position, the refrigeration cycle operation is a heating operation in which refrigerant discharged from the compressor is sent to the second heat exchanger via the four-way switching valve. If the operation immediately before the refrigeration cycle operation was a heating operation or a defrost operation in which refrigerant in the refrigerant circuit circulates in the same direction as the cooling operation, the position of the valve element after the operation is stopped is maintained in the second position or is moved to the second position.

[0006] In this refrigeration device, an operation that is started after being stopped midway through heating or defrosting operation is likely to be heating operation, so the time until heating operation starts can be shortened by setting the valve body to the second position in advance before operation starts and having the flow path switching valve unit wait in the flow path for heating operation.

[0007] A refrigeration apparatus according to a second aspect is the refrigeration apparatus according to the first aspect, wherein the pilot valve unit has a first pilot valve unit and a second pilot valve unit, and when the valve element is in the second position, the first pilot valve unit is closed and the second pilot valve unit is open, or both the first pilot valve unit and the second pilot valve unit are closed.

[0008] In this refrigeration system, the position of the valve element is maintained or the valve element is moved by a combination of opening and closing the first pilot valve section and opening and closing the second pilot valve section, making control easy.

[0009] A refrigeration apparatus according to a third aspect is the refrigeration apparatus according to the second aspect, wherein the first pilot valve section and the second pilot valve section are each an electromagnetic on-off valve, and the on-off state of the on-off valve is switched by switching the energized state.

[0010] In this refrigeration system, the first pilot valve unit and the second pilot valve unit can be switched between open and closed states by energizing or de-energizing them, so the valve body can be operated more quickly than a motor-driven valve.

[0011] A refrigeration apparatus according to a fourth aspect is the refrigeration apparatus according to the third aspect, further comprising a control unit that controls the four-way selector valve. The first pilot valve unit and the second pilot valve unit are each closed when not energized and open when energized. If the operation when the refrigeration cycle operation stop command was received was heating operation, the control unit closes the first pilot valve unit and the second pilot valve unit while maintaining the position of the valve element in the second position.

[0012] In this refrigeration device, closing the first pilot valve section and the second pilot valve section after the valve body has moved means putting the first pilot valve section and the second pilot valve section into a non-energized state, thereby reducing power consumption.

[0013] A refrigeration device of a fifth aspect is the refrigeration device of the fourth aspect, wherein the control unit moves the valve element to the second position when the operation at the time of receiving a command to stop the refrigeration cycle operation is heating operation and the valve element is in a third position between the first position and the second position.

[0014] In this refrigeration device, an operation that is started after being stopped midway through heating operation is likely to be heating operation, so the time until heating operation starts can be shortened by setting the valve body to the second position in advance before operation starts and having the flow path switching valve unit wait in the heating operation flow path.

[0015] A refrigeration apparatus according to a sixth aspect is the refrigeration apparatus according to the fourth or fifth aspect, wherein when the control unit sets the position of the valve element to the second position, the control unit sets the first pilot valve unit to a closed state and the second pilot valve unit to an open state.

[0016] In this refrigeration system, the valve element is moved by a combination of opening and closing the first pilot valve section and opening and closing the second pilot valve section, making control easy.

[0017] A refrigeration device of a seventh aspect is the refrigeration device of the fourth aspect, wherein the control unit closes the second pilot valve unit if the position of the valve body is in the second position and the second pilot valve unit is in the open state when a command to stop the refrigeration cycle operation is received.

[0018] In this refrigeration device, closing the second pilot valve unit means putting the second pilot valve unit into a non-energized state, and since the first pilot valve unit and the second pilot valve unit are in a non-energized state, power consumption is reduced.

[0019] The refrigeration device of an eighth aspect is the refrigeration device of the fourth aspect, wherein when the difference between the temperature of the space to be heated and the set temperature falls within a predetermined range during heating operation and the control unit stops the compressor, the first pilot valve unit and the second pilot valve unit are closed.

[0020] In this refrigeration device, closing the first pilot valve section and the second pilot valve section after the valve body has moved means putting the first pilot valve section and the second pilot valve section into a non-energized state, thereby reducing power consumption.

[0021] A ninth aspect of the refrigeration apparatus is the refrigeration apparatus of any one of the second aspect to the eighth aspect, wherein the flow path switching valve unit further has a high-pressure refrigerant inlet port, a low-pressure refrigerant outlet port, a first pilot chamber, and a second pilot chamber. The high-pressure refrigerant inlet port introduces high-pressure refrigerant from the high-pressure side of the compressor. The low-pressure refrigerant outlet port guides the inflowing low-pressure refrigerant to the low-pressure side of the compressor. The first pilot chamber communicates with the first pilot valve unit. The second pilot chamber communicates with the second pilot valve unit. When the first pilot valve unit is in an open state and the second pilot valve unit is in a closed state, the first pilot chamber communicates with the low-pressure refrigerant outlet port and contracts, moving the valve element to the first position. When the first pilot valve unit is in a closed state and the second pilot valve unit is in an open state, the second pilot chamber communicates with the low-pressure refrigerant outlet port and contracts, moving the valve element to the second position. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a configuration diagram of an air conditioner according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the four-way selector valve when it is in a first state. [Figure 3] 4 is a cross-sectional view of a four-way switching valve in the middle of switching from a first state to a second state. FIG. [Figure 4] FIG. 4 is a cross-sectional view of the four-way selector valve in a second state. [Figure 5] FIG. 2 is an enlarged cross-sectional view of the valve body. [Figure 6] 10 is a flowchart of a stop position control of the valve body. [Figure 7] 10 is a flowchart of thermo-off control. DETAILED DESCRIPTION OF THE INVENTION

[0023] (1) Configuration of the Air Conditioner 100 Fig. 1 is a configuration diagram of an air conditioner 100 according to one embodiment of the present invention. In Fig. 1, the air conditioner 100 is a refrigeration device capable of cooling and heating operations, and includes an indoor unit 20, an outdoor unit 10, and a liquid refrigerant communication pipe 31 and a gas refrigerant communication pipe 32 for connecting the outdoor unit 10 and the indoor unit 20. The refrigerant circuit 30 of the air conditioner 100 is filled with CO2 as a refrigerant. However, the refrigerant is not limited to CO2, and other refrigerants, such as R32, may also be used.

[0024] (1-1) Indoor unit 20 The indoor unit 20 has an indoor heat exchanger 23 and an indoor fan 24. The indoor unit 20 is also 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 in response to user operations.

[0025] (1-1-1) Indoor heat exchanger 23 The indoor heat exchanger 23 is a cross-fin type fin-and-tube heat exchanger consisting of a heat transfer tube and multiple fins. The indoor heat exchanger 23 functions as a refrigerant evaporator to cool the indoor air during cooling operation, and as a refrigerant condenser to heat the indoor air during heating operation.

[0026] The indoor heat exchanger 23 is not limited to a cross-fin type fin-and-tube heat exchanger, and may be a heat exchanger of another type.

[0027] (1-1-2) Indoor fan 24 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, and may be, for example, a turbo fan.

[0028] When the indoor fan 24 is operated, the indoor unit 20 draws indoor air into the interior, exchanges heat with the refrigerant in the indoor heat exchanger 23, and then supplies the air to the room. The indoor fan 24 can also change the air volume of the air supplied to the indoor heat exchanger 23 within a predetermined air volume range.

[0029] (1-2) Outdoor unit 10 1, the outdoor unit 10 has a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, and an expansion valve 15. The outdoor unit 10 also has an outdoor fan 14.

[0030] (1-2-1) Compressor 11 The compressor 11 is a variable displacement compressor, and its rotation speed is controlled by an inverter. In this embodiment, there is only one compressor 11, but this is not limited to this, and two or more compressors may be connected in parallel depending on the number of indoor units 20 connected, etc.

[0031] (1-2-2) Four-way switching valve 12 The four-way switching valve 12 is a valve that switches the direction of refrigerant flow. 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 also connects the suction side of the compressor 11 to the gas refrigerant connection pipe 32. This is the state shown by the solid lines of the four-way switching valve 12 in Figure 1, and 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.

[0032] During heating operation, the four-way selector valve 12 connects the discharge side of the compressor 11 to the gas refrigerant connection pipe 32, and also connects the suction side of the compressor 11 to the gas side of the outdoor heat exchanger 13. This is the state shown by the dashed lines of the four-way selector valve 12 in Figure 1, and 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.

[0033] (1-2-3) Outdoor heat exchanger 13 The outdoor heat exchanger 13 is a cross-fin type fin-and-tube heat exchanger. The outdoor heat exchanger 13 functions as a refrigerant condenser during cooling operation and as a refrigerant evaporator during heating operation. The gas side of the outdoor heat exchanger 13 is connected to the four-way switching valve 12, and the liquid side is connected to the expansion valve 15.

[0034] The outdoor heat exchanger 13 is not limited to a cross-fin type fin-and-tube heat exchanger, and may be a heat exchanger of another type.

[0035] (1-2-4) Expansion valve 15 The expansion valve 15 adjusts the pressure, flow rate, etc. of the refrigerant flowing in the refrigerant circuit 30. The expansion valve 15 is disposed downstream of the outdoor heat exchanger 13 in the direction of refrigerant flow in the refrigerant circuit 30 during cooling operation.

[0036] (1-2-5) Outdoor fan 14 The outdoor fan 14 blows the drawn outdoor air into the outdoor heat exchanger 13 to exchange heat with the refrigerant. The outdoor fan 14 can vary the air volume when blowing air to the outdoor heat exchanger 13. The outdoor fan 14 is driven by an outdoor fan motor 14a.

[0037] (1-3) Control unit 90 The control unit 90 controls the operating frequency of the compressor 11 , the switching operation of the four-way switching valve 12 , and the opening degree of the expansion valve 15 based on a command signal from a remote control unit 93 .

[0038] 1, the control unit 90 has 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 a wire.

[0039] (2) Operation of the Air Conditioner 100 In the air conditioner 100, the four-way switching valve 12 can switch the refrigerant circulation cycle to either a circulation cycle during cooling operation or a circulation cycle during heating operation.

[0040] (2-1) Cooling operation In cooling operation, the four-way switching valve 12 is set to the first state (the state indicated by the solid line of the four-way switching valve 12 in FIG. 1). When the control unit 90 operates the compressor 11 in this state, a vapor compression refrigeration cycle is performed in which the outdoor heat exchanger 13 serves as a condenser and the indoor heat exchanger 23 serves as an evaporator.

[0041] The high-pressure refrigerant discharged from the compressor 11 exchanges heat with outdoor air in the outdoor heat exchanger 13 and condenses. The refrigerant that has left the outdoor heat exchanger 13 is reduced in pressure when passing through the expansion valve 15, and then exchanges heat with indoor air in the indoor heat exchanger 23 and evaporates. During this process, the air is cooled by the indoor heat exchanger 23, and the cooled air is blown into the room from the indoor unit 20 via the indoor fan 24. The refrigerant that has left the indoor heat exchanger 23 is drawn into the compressor 11 and compressed.

[0042] (2-2) Heating operation In heating operation, the four-way switching valve 12 is set to the second state (the state indicated by the dotted line of the four-way switching valve 12 in FIG. 1). When the control unit 90 operates the compressor 11 in this state, a vapor compression refrigeration cycle is performed in which the outdoor heat exchanger 13 serves as an evaporator and the indoor heat exchanger 23 serves as a condenser.

[0043] The high-pressure refrigerant discharged from the compressor 11 exchanges heat with indoor air in the indoor heat exchanger 23 and condenses. At that time, the air is heated in the indoor heat exchanger 23, and the heated air is blown out into the room from the indoor unit 20 via the indoor fan 24. The condensed refrigerant is reduced in pressure when passing through the expansion valve 15, and then evaporates by exchanging heat with outdoor air in the outdoor heat exchanger 13. The refrigerant that leaves the outdoor heat exchanger 13 is drawn into the compressor 11 and compressed.

[0044] (3) Configuration of four-way switching valve 12 Fig. 2 is a cross-sectional view of four-way switching valve 12 in Fig. 1 in a first state indicated by solid lines. Fig. 3 is a cross-sectional view of four-way switching valve 12 in Fig. 1 in the middle of switching from the first state indicated by solid lines to a second state indicated by dotted lines. Fig. 4 is a cross-sectional view of four-way switching valve 12 in Fig. 1 in the second state indicated by dotted lines. In Figs. 2, 3, and 4, four-way switching valve 12 includes flow path switching valve section 50, pilot valve section 60, and capillary tubes 81a to 81c connecting flow path switching valve section 50 and pilot valve section 60.

[0045] (3-1) Flow path switching valve unit 50 The flow path switching valve unit 50 includes a cylinder 51, a valve element 52, a first piston 53a, a second piston 53b, a piston rod 54, a first pilot chamber 55a, and a second pilot chamber 55b.

[0046] (3-1-1) Cylinder 51 Cylinder 51 is a metallic cylindrical member whose ends are closed by first plug 511 and second plug 512. When viewed from the front in Figures 2, 3, and 4, first plug 511 closes the left end of cylinder 51, and second plug 512 closes the right end of cylinder 51. First plug 511 has a through-hole 511a. Second plug 512 has a through-hole 512a.

[0047] 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 inside of the cylinder 51 with the refrigerant circuit 30.

[0048] The first flow path Pa is provided in 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 provided at a position opposite to the first flow path Pa and is connected to the suction pipe of the compressor 11.

[0049] The third flow path Pc and the fourth flow path Pd are arranged side by side with the second flow path Pb interposed therebetween in the axial direction of the cylinder 51. 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.

[0050] The interior of the cylinder 51 is a cavity 510 that communicates 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 cavity 510 side form valve seats 56 with flat sliding surfaces.

[0051] (3-1-2) Valve body 52 The valve element 52 slides in contact with the sliding surface of the valve seat 56. The valve element 52 has a length in the sliding direction that covers two adjacent openings among the openings of the second flow path Pb, the third flow path Pc, and the fourth flow path Pd. The valve element 52 also has a recess 52a on the side facing the sliding surface of the valve seat 56 that connects the two openings that it covers.

[0052] (3-1-2-1) First position of the valve body 52 2, the valve element 52 is in a position that allows communication between the openings of the second flow path Pb and the fourth flow path Pd, and this position is referred to as the first position. When the valve element 52 is in the first position, the refrigeration cycle operates in cooling mode, and high-pressure gas refrigerant discharged from the compressor 11 flows from the first flow path Pa into the cylinder 51, flows from the third flow path Pc to the outdoor heat exchanger 13, where it condenses, is decompressed by the expansion valve 15, evaporates in the indoor heat exchanger 23, and is drawn into the compressor 11 through the fourth flow path Pd and the second flow path Pb.

[0053] (3-1-2-2) Second position of the valve body 52 4, the valve element 52 is in a position that allows the openings of the second flow path Pb and the third flow path Pc to communicate with each other, and this position is referred to as the second position. When the valve element 52 is in the second position, the refrigeration cycle operates in heating mode, and high-pressure gas refrigerant discharged from the compressor 11 flows from the first flow path Pa into the cylinder 51, flows from the fourth flow path Pd to the indoor heat exchanger 23, where it condenses, is decompressed by the expansion valve 15, evaporates in the outdoor heat exchanger 13, and is drawn into the compressor 11 through the third flow path Pc and the second flow path Pb.

[0054] (3-1-2-3) Third position of the valve body 52 In Figure 3, the valve element 52 is located between the first position and the second position. This position is called the third position. The third position is a position to which the valve element 52, which is located in the first position or the second position, gradually moves.

[0055] Alternatively, when the operation is switched and the power is turned off while the valve body 52 is moving from the first position to the second position or from the second position to the first position, the valve body 52 stops at this position without reaching either the first position or the second position.

[0056] (3-1-3) First piston 53a, second piston 53b, and piston rod 54 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.

[0057] 2, 3, and 4, 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 penetrates in the axial direction.

[0058] 2, 3, and 4, 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 penetrates in the axial direction.

[0059] The piston rod 54 holds the valve body 52 and moves together with the first piston 53a and the second piston 53b.

[0060] (3-1-4) First pilot chamber 55a and second pilot chamber 55b First pilot chamber 55a is a space sandwiched between first plug 511 and first piston 53a. Second pilot chamber 55b is a space sandwiched between second plug 512 and second piston 53b.

[0061] A portion of the high-pressure refrigerant flowing in from the first flow path Pa flows through the small hole 531 of the first piston 53a into the first pilot chamber 55a, and also flows through the small hole 532 of the second piston 53b into the second pilot chamber 55b.

[0062] When there is a difference in pressure 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 body 52 move.

[0063] For example, in Figure 2, the pressure in the first pilot chamber 55a is smaller than the pressure in the second pilot chamber 55b, so the first piston 53a, the second piston 53b, the piston rod 54, and the valve body 52 move to the left when viewed from the front in Figure 2, and the position of the valve body 52 at that time is the first position.

[0064] Also, in Figure 4, since 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 body 52 move to the right when viewed from the front in Figure 4, and the position of the valve body 52 at that time is the second position.

[0065] (3-2) Pilot valve section 60 The pilot valve portion 60 has a first pilot valve portion 60a and a second pilot valve portion 60b.

[0066] (3-2-1) First pilot valve portion 60a The first pilot valve portion 60a has 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 coil spring 65a.

[0067] The valve body 61 also serves as the second pilot valve portion 60b. The first valve seat 61a is formed inside the valve body 61. The first valve chamber 62a is a space in which the first plunger 63a moves, and communicates with an opening in the first valve seat 61a.

[0068] 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, it generates an electromagnetic force to move the first plunger 63a in a direction away from the opening of the first valve seat 61a. The first coil spring 65a constantly pushes the first plunger 63a in a direction to close the opening of the first valve seat 61a.

[0069] The electromagnetic force of the first solenoid 64a is greater than the force with which the first coil spring 65a presses the first plunger 63a, so when the first solenoid 64a is energized, the opening of the first valve seat 61a opens.When the first solenoid 64a is not energized, the first coil spring 65a presses the first plunger 63a to close the opening of the first valve seat 61a.

[0070] (3-2-2) Second pilot valve portion 60b The second pilot valve portion 60b has 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 coil spring 65b.

[0071] The valve body 61 also serves as the first pilot valve portion 60a. The second valve seat 61b is formed inside the valve body 61. The second valve chamber 62b is a space in which the second plunger 63b moves, and communicates with an opening in the second valve seat 61b.

[0072] 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, it generates an electromagnetic force to move the second plunger 63b in a direction away from the opening of the second valve seat 61b. The second coil spring 65b constantly pushes the second plunger 63b in a direction to close the opening of the second valve seat 61b.

[0073] The electromagnetic force of the second solenoid 64b is greater than the force with which the second coil spring 65b pushes the second plunger 63b, so when the second solenoid 64b is energized, the opening of the second valve seat 61b opens.When the second solenoid 64b is not energized, the second coil spring 65b pushes the second plunger 63b to close the opening of the second valve seat 61b.

[0074] (3-2-3) Configuration of the valve body 61 Fig. 5 is an enlarged cross-sectional view of the valve body 61. In Fig. 5, an opening of a first valve seat 61a and an opening of a second valve seat 61b formed in the valve body 61 communicate with each other via a first communication hole 611. The valve body 61 also has a second communication hole 612, a third communication hole 613, and a fourth communication hole 614.

[0075] The second communication hole 612 communicates with the first communication hole 611. Furthermore, the second communication hole 612 is connected to the second flow path Pb of the flow path switching valve unit 50 via a capillary tube 81c, as shown in FIGS.

[0076] The third communication hole 613 communicates with the first valve chamber 62a. In addition, the third communication hole 613 is connected to the first pilot chamber 55a of the flow path switching valve unit 50 via a capillary tube 81a, as shown in Figures 2, 3, and 4.

[0077] The fourth communication hole 614 communicates with the second valve chamber 62b. In addition, the fourth communication hole 614 is connected to the second pilot chamber 55b of the flow path switching valve unit 50 via a capillary tube 81b, as shown in Figures 2, 3, and 4.

[0078] (4) Operation of the four-way switching valve 12 The four-way switching valve 12 switches the position of the valve element 52 of the flow path switching valve section 50 between the first position and the second position by switching between opening and closing the first pilot valve section 60a and the second pilot valve section 60b.

[0079] The following explanation will be based on the assumption that when the first pilot valve section 60a is energized and in an open state, the second pilot valve section 60b is de-energized and in a closed state, and when the first pilot valve section 60a is de-energized and in a closed state, the second pilot valve section 60b is energized and in an open state.

[0080] (4-1) When the first pilot valve portion 60a is open and the second pilot valve portion is closed 2 and 5, when the first solenoid 64a is energized, the electromagnetic force of the first solenoid 64a moves the first plunger 63a away from the opening of the first valve seat 61a against the spring force of the first coil spring 65a. As a result, the opening of the first valve seat 61a opens, the first valve chamber 62a communicates with the third communication hole 613, the refrigerant flows from the first pilot chamber 55a of the flow path switching valve unit 50 to the second flow path Pb via the capillary tubes 81a and 81c, and the pressure in the first pilot chamber 55a changes to low.

[0081] On the other hand, because the second solenoid 64b is not energized, the second plunger 63b is pushed by the second coil spring 65b in a direction to close the second valve seat 61b. Therefore, the second plunger 63b blocks communication between the second valve chamber 62b and the fourth communication hole 614, so that refrigerant does not flow from the second pilot chamber 55b of the flow path switching valve unit 50 to the second flow path Pb, and the second pilot chamber 55b maintains a high pressure.

[0082] As a result, the first piston 53a, the second piston 53b, the piston rod 54, and the valve body 52 move in a direction that reduces the space of the first pilot chamber 55a, and the valve body 52 reaches the first position. At this time, the first flow path Pa and the third flow path Pc communicate with each other, and the high-pressure gas refrigerant from the compressor 11 flows to the outdoor heat exchanger 13, and the second flow path Pb and the fourth flow path Pd communicate with each other, and the low-pressure refrigerant from the indoor heat exchanger 23 is drawn into the compressor 11.

[0083] (4-2) When the first pilot valve portion 60a is closed and the second pilot valve portion is open 4 and 5, when the second solenoid 64b is energized, the electromagnetic force of the second solenoid 64b moves the second plunger 63b away from the opening of the second valve seat 61b against the spring force of the second coil spring 65b. As a result, the opening of the second valve seat 61b opens, the second valve chamber 62b communicates with the fourth communication hole 614, the refrigerant flows from the second pilot chamber 55b of the flow path switching valve unit 50 to the second flow path Pb via the capillary tubes 81b and 81c, and the pressure in the second pilot chamber 55b changes to low.

[0084] On the other hand, because the first solenoid 64a is not energized, the first plunger 63a is pushed by the first coil spring 65a in a direction to close the first valve seat 61a. Therefore, the first plunger 63a blocks communication between the first valve chamber 62a and the third communication hole 613, so that refrigerant does not flow from the first pilot chamber 55a of the flow path switching valve unit 50 to the second flow path Pb, and the first pilot chamber 55a maintains a high pressure.

[0085] As a result, the first piston 53a, the second piston 53b, the piston rod 54, and the valve body 52 move in a direction that reduces the space of the second pilot chamber 55b, and the valve body 52 reaches the second position. At this time, the first flow path Pa and the fourth flow path Pd communicate with each other, and the high-pressure gas refrigerant from the compressor 11 flows to the indoor heat exchanger 23, and the second flow path Pb and the third flow path Pc communicate with each other, and the low-pressure refrigerant from the outdoor heat exchanger 13 is drawn into the compressor 11.

[0086] (5) Stop position control of the valve element 52 in the four-way switching valve 12 In the four-way switching valve described in Patent Document 1 cited in the background art, when the pilot solenoid valve is energized, the valve element moves against the spring force and switches to the heating operation cycle, and when the pilot solenoid valve is de-energized, the valve element returns by the spring force and switches to the cooling operation cycle.

[0087] Therefore, even in winter when heating operation is performed, when the air conditioner stops operation, the valve body inside the four-way switching valve moves and waits in the cooling operation cycle position, so it takes time from receiving a heating operation command to starting heating operation.

[0088] Therefore, in the air conditioner 100 of this embodiment, if the operation immediately before the refrigeration cycle operation is stopped is heating operation, or defrost operation in which the refrigerant in the refrigerant circuit circulates in the same direction as cooling operation, the position of the valve body 52 after operation is stopped is maintained in the second position or moved to the second position, thereby shortening the time from receiving a command to start heating operation to starting heating operation.

[0089] Here, "immediately before the refrigeration cycle operation is stopped" means immediately before an operation stop command is received. Also, "operation stopped" means a state in which at least the compressor 11 is stopped.

[0090] 6 is a flowchart of the stop position control of the valve element 52. The stop position control of the valve element 52 will be described below with reference to the drawings.

[0091] (Step S1) In step S1, the control unit 90 determines whether or not there is a command to stop operation of the air conditioner 100, and if there is a command to stop operation, the process proceeds to step S2.

[0092] (Step S2) In step S2, the control unit 90 stops the air conditioner 100, and proceeds to step S3.

[0093] (Step S3) In step S3, the control unit 90 determines whether the air conditioner 100 has stopped in heating operation. If the control unit 90 determines that the air conditioner 100 has stopped in heating operation, the control unit 90 proceeds to step S4. If the control unit 90 determines that the air conditioner 100 has not stopped in heating operation, the control unit 90 proceeds to step S5.

[0094] (Step S4) In step S4, the control unit 90 maintains the valve element 52 of the four-way switching valve 12 in the second position. When the air conditioner 100 is stopped in heating operation, the valve element 52 of the four-way switching valve 12 is in the second position. Therefore, if the position of the valve element 52 is maintained in the second position, there is no need to move the position of the valve element 52 the next time heating operation is started, and the time from when a command for heating operation is received until heating operation starts is shortened.

[0095] Furthermore, the process of “maintaining the position of the valve element 52 at the second position” in step S4 specifically means “closing the first pilot valve portion 60a and opening the second pilot valve portion 60b, or closing both the first pilot valve portion 60a and the second pilot valve portion 60b.” This allows the valve element 52 to be set and maintained at the second position.

[0096] Furthermore, the process of "closing the first pilot valve section 60a and opening the second pilot valve section 60b, or closing both the first pilot valve section 60a and the second pilot valve section 60b" specifically means "de-energizing the first pilot valve section 60a and energizing the second pilot valve section 60b, or de-energizing both the first pilot valve section 60a and the second pilot valve section 60b." For ease of explanation, the former will be referred to as Process A and the latter as Process B.

[0097] When the first pilot valve portion 60a is not energized but the second pilot valve portion 60b is energized as in process A, no electromagnetic force is generated in the first solenoid 64a, and the first valve seat 61a is closed by the first plunger 63a. On the other hand, the second solenoid 64b is energized, and the second plunger 63b is moved away from the second valve seat 61b by the electromagnetic force, and the second pilot chamber 55b of the flow path switching valve portion 50 communicates with the second flow path Pb. As a result, the second pilot chamber 55b contracts, and the valve element 52 moves to the second position.

[0098] The advantage of process A is that, for example, if operation is stopped at the time of switching from defrost operation to heating operation and valve body 52 stops between the first position and the second position, valve body 52 is reliably moved to the second position.

[0099] On the other hand, when the first pilot valve portion 60a and the second pilot valve portion 60b are not energized as in process B, 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 portion 50 is maintained, and the position of the valve element 52 is also maintained in the second position.

[0100] In this embodiment, when a stop command is issued during heating operation, the valve element 52 is in the second position and the second pilot valve portion 60b is in the open state. Since energizing the second pilot valve portion 60b to maintain the open state after operation is stopped results in unnecessary power consumption, it is more rational to perform process B, which does not energize the second pilot valve portion 60b after operation is stopped. Therefore, it is desirable to perform process B after process A.

[0101] (Step S5) In step S5, the control unit 90 determines whether or not the air conditioner 100 has stopped in defrost operation. If the control unit 90 determines that the air conditioner 100 has stopped in defrost operation, the process proceeds to step S6.

[0102] Furthermore, when the control unit 90 determines that the air conditioner 100 is not stopped in defrost operation, it determines that the operation is neither heating operation nor defrost operation, and therefore is not subject to stop position control of the valve body 52, and terminates the control.

[0103] (Step S6) In step S6, the control unit 90 moves the valve element 52 of the four-way switching valve 12 to the second position. When the air conditioner 100 is stopped in defrost operation, the valve element 52 of the four-way switching valve 12 is in the first position. Therefore, if the position of the valve element 52 is moved from the first position to the second position, the next time heating operation is started, there is no need to move the position of the valve element 52, and the time from receiving a heating operation command to starting heating operation is shortened.

[0104] Furthermore, the process of "moving the valve element 52 to the second position" in step S6 is specifically a process of "closing the first pilot valve portion 60a and opening the second pilot valve portion 60b." As a result, the valve element 52 moves to the second position.

[0105] Furthermore, the process of "closing the first pilot valve portion 60a and opening the second pilot valve portion 60b" specifically means "de-energizing the first pilot valve portion 60a and energizing the second pilot valve portion 60b." In this case, no electromagnetic force is generated in the first solenoid 64a, and the first valve seat 61a is closed by the first plunger 63a.

[0106] Meanwhile, the second solenoid 64b is energized, the second plunger 63b is moved away from the second valve seat 61b by electromagnetic force, and the second pilot chamber 55b of the flow path switching valve unit 50 communicates with the second flow path Pb. As a result, the second pilot chamber 55b contracts, and the valve element 52 moves to the second position.

[0107] An operation that is started after being stopped midway through heating operation or defrosting operation is likely to be heating operation, so the time until heating operation starts can be shortened by setting the valve body 52 to the second position in advance before the operation starts and having the flow path switching valve unit 50 wait in the flow path for heating operation.

[0108] After the process of "de-energizing the first pilot valve portion 60a and energizing the second pilot valve portion 60b" is performed, it is desirable to stop energizing the first pilot valve portion 60a and the second pilot valve portion 60b. This is because even if the energization is stopped, the position of the valve element 52 is maintained in the second position, thereby suppressing unnecessary power consumption.

[0109] As a supplementary note regarding the stop position control of the valve element 52, step S2 in FIG. 6 may be executed after the processing of steps S4 and S6.

[0110] In this case, step S3 does not determine whether the operation has been stopped during heating operation, but determines whether the operation when the operation stop command was received in step S1 was heating operation.

[0111] Similarly, in step S5, it is not determined whether the operation was stopped during defrosting operation, but rather it is determined whether the operation when the operation stop command was received in step S1 was defrosting operation.

[0112] (6) Variations In the above embodiment, the first pilot valve portion 60a is open when energized and closed when de-energized, and the second pilot valve portion 60b is also open when energized and closed when de-energized. However, this is not limited to this, and the first pilot valve portion 60a may be closed when energized and open when de-energized, and the second pilot valve portion 60b may also be closed when energized and open when de-energized.

[0113] (7) Features (7-1) In the air conditioner 100, if the operation immediately before the refrigeration cycle operation was stopped was heating operation or defrost operation in which the refrigerant in the refrigerant circuit circulates in the same direction as cooling operation, the position of the valve element 52 after operation is stopped is maintained at the second position or moved to the second position. As a result, the time from the operation stop state to the start of heating operation can be shortened.

[0114] (7-2) In the air conditioner 100, when the valve element 52 is in the second position, the first pilot valve section 60a is closed and the second pilot valve section 60b is open, or both the first pilot valve section 60a and the second pilot valve section 60b are closed. The position of the valve element 52 is maintained or the valve element 52 is moved by a combination of opening and closing the first pilot valve section 60a and the second pilot valve section 60b, making control easy.

[0115] (7-3) In the air conditioner 100, the first pilot valve portion 60a and the second pilot valve portion 60b can be switched between open and closed states by energizing or de-energizing them, so the valve bodies can be operated more quickly than with motor-driven valves.

[0116] (7-4) In the air conditioner 100, closing the first pilot valve section 60a and the second pilot valve section 60b after the valve body 52 has moved means putting the first pilot valve section 60a and the second pilot valve section 60b into a non-energized state, thereby reducing power consumption.

[0117] (7-5) In the air conditioner 100, when a command to stop the refrigeration cycle operation is received and the operation is heating operation, and the valve element 52 is in a third position between the first position and the second position, the control unit 90 moves the valve element 52 to the second position. As a result, the time from the operation stop state to the start of the heating operation can be shortened.

[0118] (7-6) In the air conditioner 100, when the control unit 90 sets the position of the valve element 52 to the second position, it closes the first pilot valve unit 60a and opens the second pilot valve unit 60b. The movement of the valve element 52 is achieved by a combination of opening and closing the first pilot valve unit 60a and the second pilot valve unit 60b, making control easy.

[0119] (7-7) In the air conditioner 100, if the position of the valve element 52 is the second position and the second pilot valve unit 60b is in the open state when a command to stop the refrigeration cycle operation is received, the control unit 90 closes the second pilot valve unit 60b. Closing the second pilot valve unit 60b means de-energizing the second pilot valve unit 60b, and the first pilot valve unit 60a and the second pilot valve unit 60b are de-energized, thereby reducing power consumption.

[0120] (7-8) When the first pilot valve portion 60a is in the open state and the second pilot valve portion 60b is in the closed state, the first pilot chamber 55a of the four-way switching valve 12 communicates with the second flow path Pb and contracts, moving the valve element 52 to the first position. When the first pilot valve portion 60a is in the closed state and the second pilot valve portion 60b is in the open state, the second pilot chamber 55b of the four-way switching valve 12 communicates with the second flow path Pb and contracts, moving the valve element 52 to the second position.

[0121] (8) Other embodiments When the air conditioner 100 is a paired unit in which one outdoor unit 10 is connected to one indoor unit 20, the stop position control of the valve body 52 is not limited to when operation is stopped due to the power being turned off.

[0122] For example, when the difference between the indoor temperature setting and the indoor temperature falls within a predetermined range and the compressor 11 is stopped, ie, when the so-called thermo-off state is reached, the stop position of the valve body 52 is also controlled.

[0123] 7 is a flowchart of thermo-off control. Here, as an example, stop position control of the valve element 52 according to another embodiment will be described with reference to FIG.

[0124] (Step S11) In step S11, the control unit 90 acquires an indoor set temperature Ts as the set temperature of the room, which is the space to be air-conditioned. The indoor set temperature Ts is set by the user via the remote control unit 93.

[0125] (Step S12) In step S12, the control unit 90 detects the room temperature Tr via the room temperature sensor 95. The room temperature sensor 95 is disposed in the indoor unit 20.

[0126] (Step S13) 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 equal to or less than 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 equal to or less than the predetermined value X, the process 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 equal to or less than the predetermined value X, the process returns to step S11.

[0127] (Step S14) In step S14, the control unit 90 stops the compressor 11, and the process proceeds to step S3 shown in FIG.

[0128] (Step S3) In step S3, the control unit 90 determines whether the air conditioner 100 has stopped in heating operation. If the control unit 90 determines that the air conditioner 100 has stopped in heating operation, the control unit 90 proceeds to step S4. If the control unit 90 determines that the air conditioner 100 has not stopped in heating operation, the control unit 90 proceeds to step S5.

[0129] (Step S4) In step S4, the control unit 90 maintains the valve element 52 of the four-way switching valve 12 in the second position. To maintain the valve element 52 in the second position, specifically, the first pilot valve portion 60a is closed and the second pilot valve portion 60b is opened, or both the first pilot valve portion 60a and the second pilot valve portion 60b are closed. This determines and maintains the valve element 52 in the second position.

[0130] (Step S5) In step S5, the control unit 90 determines whether the air conditioner 100 has stopped in defrost operation. If the control unit 90 determines that the air conditioner 100 has stopped in defrost operation, the control unit 90 proceeds to step S6. If the control unit 90 determines that the air conditioner 100 has not stopped in defrost operation, the control unit 90 ends the control.

[0131] (Step S6) In step S6, the control unit 90 moves the valve element 52 of the four-way switching valve 12 to the second position. To move the valve element 52 to the second position, specifically, the first pilot valve element 60a is closed and the second pilot valve element 60b is opened. This moves the valve element 52 to the second position.

[0132] Since the operation that starts from the thermo-off state of the heating operation is the heating operation, the time until the heating operation starts can be shortened by setting the valve body 52 to the second position in advance before the operation starts and making the flow path switching valve unit 50 wait in the flow path for the heating operation.

[0133] Furthermore, it is desirable to close the first pilot valve portion 60a and the second pilot valve portion 60b after the valve element 52 has been moved to the second position, because closing the first pilot valve portion 60a and the second pilot valve portion 60b after the valve element 52 has moved means that the first pilot valve portion 60a and the second pilot valve portion 60b are de-energized, thereby reducing power consumption.

[0134] Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure as defined in the claims. [Explanation of symbols]

[0135] 11 Compressor 12 Four-way switching valve 13 Outdoor heat exchanger (1st heat exchanger) 15 Expansion valve 23 Indoor heat exchanger (second heat exchanger) 30 Refrigerant circuit 50 Flow path switching valve 52 Valve body 55a First Pilot Room 55b Second Pilot Room 60 Pilot valve section 60a First pilot valve section 60b Second pilot valve section 90 Control Unit 100 Air conditioners (refrigeration units) Pa First flow path (high-pressure refrigerant inlet) Pb Second flow path (low pressure refrigerant inlet) Pc Third flow path Pd 4th flow path [Prior art documents] [Patent documents]

[0136] [Patent Document 1] Jikko No. 55-53825

Claims

[Claim 1] A refrigeration system in which a refrigerant circulates through a refrigerant circuit (30) including a compressor (11), a four-way switching valve (12), a first heat exchanger (13), an expansion valve (15), and a second heat exchanger (23), and a refrigeration cycle operation is performed, The four-way switching valve (12) is a flow path switching valve unit (50) having a valve element (52) movable between a first position and a second position different from the first position; a pilot valve portion (60) which is an electromagnetic open / close valve that moves the valve body (52); Equipped with The refrigeration cycle operation is When the valve body (52) is in the first position, a cooling operation is performed in which the refrigerant discharged from the compressor (11) is sent to the first heat exchanger (13) via the four-way switching valve (12), When the valve body (52) is in the second position, a heating operation is performed in which the refrigerant discharged from the compressor (11) is sent to the second heat exchanger (23) via the four-way switching valve (12), the pilot valve portion (60) maintains the position of the valve element (52) immediately before the supply of current to the pilot valve portion (60) is stopped even after the supply of current to the pilot valve portion (60) is stopped; If the heating operation was performed immediately before the refrigeration cycle operation was stopped, the position of the valve body (52) after the operation was stopped is maintained at the second position, and if the defrost operation in which the refrigerant in the refrigerant circuit (30) circulates in the same direction as the cooling operation was performed immediately before the refrigeration cycle operation was stopped, the position of the valve body (52) after the operation was stopped is moved to the second position. A refrigeration device (100).

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