Air conditioning system and its installation method

Abstract

This invention provides an air conditioning system and its installation method that can prevent air from entering the refrigerant circuit when a ball valve is used as a valve to open and close the flow path. [Solution] An air conditioning device according to one embodiment of the present invention comprises a refrigerant circuit, a ball valve, and a control unit. The ball valve has a ball-shaped valve body having a radially penetrating flow path, a valve chamber housing the valve body, and a drive unit that rotates the valve body within the valve chamber. The valve chamber is divided by the valve body into a first space communicating with the refrigerant passage and a second space communicating with the drive unit. The control unit controls the ball valve so as to be switchable between an open state in which the flow path communicates only with the first space, a closed state in which the flow path communicates only with the second space, and an intermediate state in which the flow path communicates with both the first and second spaces. When the refrigerant circuit is evacuated, the control unit performs a first opening adjustment process, which is the process of setting the ball valve to the intermediate state.

Description

Technical Field

[0001] The present invention relates to an air conditioner and an installation method thereof.

Background Art

[0002] In an air conditioner, there is one in which a valve for opening and closing a flow path is provided in a refrigerant pipe forming a refrigerant circuit. For example, Patent Document 1 discloses an air conditioner including an indoor unit, an outdoor unit, and a shut-off valve disposed in a refrigerant pipe (liquid pipe and gas pipe) connecting the indoor unit and the outdoor unit. The shut-off valve is composed of an opening and closing valve such as a ball valve and is disposed in the liquid pipe and the gas pipe, respectively. Each shut-off valve shuts off the liquid pipe and the gas pipe when refrigerant leakage is detected in the indoor unit and the refrigerant pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when installing an air conditioner, after connecting the outdoor unit and the indoor unit with a refrigerant pipe, installation work such as checking the airtightness of the refrigerant circuit, evacuation after checking the airtightness, and filling the refrigerant circuit with refrigerant is performed. The evacuation and refrigerant filling operations of the refrigerant circuit are usually performed while maintaining the valve devices arranged in the refrigerant circuit, such as shut-off valves and expansion valves, in an open state. [[ID=XX]] [[ID=XX]]

[0005] [[ID=XX]] Here, a ball valve is a valve device comprising a valve body (ball) having a through hole that penetrates radially, a valve chamber that houses the valve body, and a drive unit for adjusting the opening degree of the ball valve between a fully open state in which the through hole is aligned with the flow path and a fully closed state in which the through hole does not communicate with the flow path by rotating the valve body within the valve chamber. In a ball valve, there is a space in the valve chamber that does not communicate with the flow path when the valve body is fully open, and a space (dead space) from which air cannot be drawn in is created when vacuuming the refrigerant circuit, which is performed in the fully open state. For this reason, when a ball valve is used as a shut-off valve, if the shut-off valve is opened and closed to check the operation of the shut-off valve after vacuuming the refrigerant circuit or charging the refrigerant, air in the dead space in the valve chamber that cannot be vacuumed in may be mixed into the refrigerant circuit, and the following problems may occur.

[0006] For example, if air is mixed into the condenser that forms the refrigerant circuit, the heat exchange (liquefaction) of the refrigerant in the condenser is hindered during air conditioning operation, causing the condensation pressure to rise. This rise in condensation pressure increases the load on the compressor, degrading air conditioning performance. Furthermore, the rise in condensation pressure makes the compressor's high-pressure protection control more likely to activate, potentially leading to more frequent starting and stopping of the compressor and a reduction in its lifespan.

[0007] In view of the above circumstances, the object of the present invention is to provide an air conditioning device and a method for installing the same that can prevent air from entering the refrigerant circuit when a ball valve is used as a valve for opening and closing the flow path. [Means for solving the problem]

[0008] An air conditioning device according to one embodiment of the present invention comprises a refrigerant circuit, a ball valve, and a control unit. The refrigerant circuit comprises an outdoor unit having a compressor and an outdoor heat exchanger, an indoor unit having an indoor heat exchanger, and a refrigerant passage connecting the outdoor unit and the indoor unit. The ball valve is provided in the refrigerant passage. The control unit controls the ball valve. The ball valve is a valve device comprising a ball-shaped valve body having a flow path portion that penetrates radially, a valve chamber housing the valve body, and a drive unit that rotates the valve body within the valve chamber, wherein the valve chamber is divided by the valve body into a first space that communicates with the refrigerant passage and a second space that communicates with the drive unit. The control unit controls the ball valve so as to be switchable between an open state in which the flow path communicates only with the first space, a closed state in which the flow path communicates only with the second space, and an intermediate state in which the flow path communicates with both the first and second spaces. When the refrigerant circuit is evacuated, the control unit performs a first opening degree adjustment process, which is the process of setting the ball valve to the intermediate state.

[0009] In the present invention, the vacuuming process of the refrigerant circuit performed when installing an air conditioning system includes setting the opening degree of the ball valve to an intermediate state, thereby allowing the dead space inside the ball valve to be exhausted and preventing air from entering the refrigerant circuit.

[0010] The control unit may, when vacuuming of the refrigerant circuit is started, perform a second opening adjustment process, which is the process of switching the ball valve to the open state, before performing the first opening adjustment process, and then perform the first opening adjustment process when the pressure of the refrigerant circuit reaches below a predetermined value due to vacuuming being performed in the open state.

[0011] The control unit may also perform the second opening degree adjustment process when the pressure in the refrigerant circuit falls below the predetermined value due to the vacuuming performed in the intermediate state.

[0012] The aforementioned open valve state may also be the fully open state of the ball valve.

[0013] The control unit may perform the first opening adjustment process when vacuuming of the refrigerant circuit is started, and when the pressure of the refrigerant circuit reaches a predetermined value or less due to the vacuuming being performed in the intermediate state, it may perform a second opening adjustment process, which is the process of setting the ball valve to the open state.

[0014] The refrigerant passage may include a gas pipe through which gaseous refrigerant flows and a liquid pipe through which liquid refrigerant flows, and the shut-off valve may be located in the gas pipe and the liquid pipe, respectively.

[0015] The control unit may include a switching unit that generates a control command to switch the ball valve between the open state and the intermediate state when it determines that the pressure in the refrigerant passage has reached or below the detection pressure of the pressure sensor that detects the pressure in the refrigerant passage.

[0016] The switching unit may be mounted on the outdoor unit or on the ball valve.

[0017] A method for installing an air conditioning system according to one embodiment of the present invention comprises an outdoor unit having a compressor and an outdoor heat exchanger, an indoor unit having an indoor heat exchanger, a refrigerant circuit having a refrigerant passage connecting the outdoor unit and the indoor unit, and a ball valve provided in the refrigerant passage, The ball valve comprises a ball-shaped valve body having a flow path portion that penetrates radially, a valve chamber housing the valve body, and a drive unit that rotates the valve body within the valve chamber, wherein the valve chamber is divided by the valve body into a first space communicating with the refrigerant passage and a second space communicating with the drive unit. When evacuating the refrigerant circuit, the process includes at least the steps of connecting a vacuum pump to the refrigerant passage, setting the ball valve to an intermediate state in which the flow path communicates with both the first space and the second space, and then evacuating the refrigerant circuit and the second space using the vacuum pump. [Effects of the Invention]

[0018] According to the present invention, when a ball valve is adopted as a valve for opening and closing a flow path, it is possible to prevent air from being mixed into the refrigerant circuit.

Brief Description of the Drawings

[0019] [Figure 1] It is a refrigerant circuit diagram showing a configuration example of an air conditioner according to an embodiment of the present invention. [Figure 2] It is a schematic side sectional view showing a configuration example of a ball valve. [Figure 3] It is a schematic perspective view for explaining the operation of a ball valve. [Figure 4] It is a block diagram showing the configuration of a control unit. [Figure 5] It is a schematic diagram for explaining the opening degree of a ball valve. (A) and (B) show the valve opening state, (C) shows the intermediate state, and (D) shows the valve closing state (fully closed state). [Figure 6] It is a processing flow showing an example of a procedure for adjusting the opening degree of a shut-off valve in the evacuation process of a refrigerant circuit. [Figure 7] It is a conceptual diagram for explaining the evacuation process of a refrigerant circuit. [Figure 8] It is a schematic diagram for explaining the intermediate state of a ball valve. [Figure 9] It is a processing flow showing another example of a procedure for adjusting the opening degree of a shut-off valve in the evacuation process of a refrigerant circuit. [Figure 10] It is a refrigerant circuit diagram showing another configuration example of the above air conditioner.

Modes for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0021] Figure 1 is a refrigerant circuit diagram showing one example configuration of an air conditioning system 100 according to one embodiment of the present invention. The air conditioning system 100 will be described using an example in which one outdoor unit 2 is connected in parallel to three indoor units 8a, 8b, and 8c as indoor units. Note that the number of indoor units is not limited to three, but may be one, two, or four or more.

[0022] [Air conditioning system] First, with reference to Figure 1, the configuration of the air conditioning system 100 will be explained.

[0023] As shown in Figure 1, the air conditioning system 100 comprises an outdoor unit 2 and three indoor units 8a, 8b, and 8c. The refrigerant circuit 10 of the air conditioning system 100 is formed by connecting the outdoor unit 2 and the indoor units 8a to 8c with a liquid pipe 31 through which liquid refrigerant mainly flows and a gas pipe 32 through which gaseous refrigerant mainly flows. In this embodiment, the outdoor unit 2 has one outdoor heat exchanger 24, but it may have two or more outdoor heat exchangers.

[0024] (Outdoor unit) The outdoor unit 2 is equipped with a compressor 21, a four-way valve 22, an outdoor heat exchanger 24, an outdoor fan 26, an accumulator 27, and an outdoor expansion valve 40.

[0025] The compressor 21 is a variable-capacity compressor whose operating capacity can be varied by being driven by a motor (not shown) whose rotational speed is controlled by an inverter. The refrigerant discharge port of the compressor 21 is connected to port a of the four-way valve 22 by a discharge pipe 28. The refrigerant suction port of the compressor 21 is connected to the outlet side of the accumulator 27 by a suction pipe 42.

[0026] The four-way valve 22 is a flow path switching valve for switching the direction of refrigerant flow in the refrigerant circuit 10, switching the connection of one refrigerant inlet / outlet of the outdoor heat exchanger 24 to the refrigerant outlet or refrigerant inlet of the compressor 21. The four-way valve 22 has four ports a, b, c, and d. Port a is connected to the refrigerant outlet of the compressor 21 by the discharge pipe 28. Port b is connected to one refrigerant inlet / outlet of the outdoor heat exchanger 24 by the refrigerant pipe 37. Port c is connected to the inlet side of the accumulator 27 by the refrigerant pipe 36. Port d is connected to the gas side shut-off valve 46 by the outdoor unit gas pipe 34.

[0027] One refrigerant inlet / outlet of the outdoor heat exchanger 24 is connected to port b of the four-way valve 22 via refrigerant piping 37 as described above, and the other refrigerant inlet / outlet of the outdoor heat exchanger 24 is connected to one port of the outdoor expansion valve 40. The other port of the outdoor expansion valve 40 is connected to the liquid side shut-off valve 45 and the outdoor unit liquid pipe 35. The outdoor heat exchanger 24 functions as a condenser during cooling operation and as an evaporator during heating operation by switching the four-way valve 22.

[0028] The accumulator 27 has its inlet side connected to port c of the four-way valve 22 by refrigerant piping 36, and its outlet side connected to the refrigerant inlet of the compressor 21 by suction piping 42. The accumulator 27 separates the incoming refrigerant into gaseous refrigerant and liquid refrigerant, and allows only the gaseous refrigerant to be drawn into the compressor 21.

[0029] The outdoor fan 26 is positioned near the outdoor heat exchanger 24. The outdoor fan 26 rotates using a fan motor (not shown) to draw outside air into the outdoor unit 2, exchange heat between the refrigerant and the outside air in the outdoor heat exchanger 24, and then releases the heat-exchanged outside air to the outside of the outdoor unit 2.

[0030] The outdoor expansion valve 40 is an electronic expansion valve driven by a pulse motor (not shown) and is located in the outdoor unit liquid pipe 35. Specifically, the opening degree of the outdoor expansion valve 40 is adjusted to an opening degree between fully closed and fully open by the number of pulses applied to the pulse motor. The opening degree of the outdoor expansion valve 40 is adjusted according to the heating capacity required by the indoor units 8a to 8c during heating operation, and according to the cooling capacity required by the indoor units 8a to 8c during cooling operation.

[0031] The outdoor unit 2 is equipped with various sensors. As shown in Figure 1, the discharge pipe 28 is equipped with a high-pressure sensor 50 for detecting the pressure of the refrigerant discharged from the compressor 21 and a discharge temperature sensor 53 for detecting the temperature of the refrigerant discharged from the compressor 21. The suction pipe 42 is equipped with a low-pressure sensor 51 for detecting the pressure of the refrigerant drawn into the compressor 21 and a suction temperature sensor 54 for detecting the temperature of the refrigerant drawn into the compressor 21.

[0032] Furthermore, the outdoor heat exchanger 24 is equipped with a heat exchanger temperature sensor 56 that detects the temperature of the refrigerant flowing inside the outdoor heat exchanger 24. In addition, an outdoor air temperature sensor 58 is provided that detects the temperature of the outside air flowing into the outdoor unit 2, i.e., the outside air temperature.

[0033] (indoor unit) The three indoor units 8a to 8c are equipped with an indoor heat exchanger 81, an indoor expansion valve 82, and an indoor fan 83. Since the configuration of each indoor unit 8a to 8c is the same, the following explanation will only describe the configuration of indoor unit 8a, and the explanations for the other indoor units 8b and 8c will be omitted.

[0034] The indoor heat exchanger 81 has one end (one refrigerant inlet / outlet) connected to a liquid branch pipe 71 that branches off from the liquid pipe 31, and the other end (the other refrigerant inlet / outlet) connected to a gas branch pipe 72 that branches off from the gas pipe 32. The indoor heat exchanger 81 functions as an evaporator when the indoor unit 8a is in cooling operation, and as a condenser when the indoor unit 8a is in heating operation.

[0035] The indoor expansion valve 82 is located in the liquid branch pipe 71, with one port connected to the indoor heat exchanger 81 and the other port connected to the liquid pipe 31 via the liquid branch pipe 71. The opening degree of the indoor expansion valve 82 is adjusted according to the state of the refrigerant flowing into the indoor heat exchanger 81.

[0036] The indoor fan 83 is located near the indoor heat exchanger 81. The indoor fan 83 rotates with a fan motor (not shown) to draw indoor air into the indoor unit 8a, and after heat exchange between the refrigerant and the indoor air in the indoor heat exchanger 81, it supplies the heat-exchanged air to the room.

[0037] The indoor unit 8a is equipped with various sensors. A refrigerant temperature sensor 84 for detecting the temperature of the refrigerant is provided on the refrigerant piping at one end (one refrigerant inlet / outlet) of the indoor heat exchanger 81, and a refrigerant temperature sensor 85 for detecting the temperature of the refrigerant is provided on the refrigerant piping at the other end (the other refrigerant inlet / outlet) of the indoor heat exchanger 81. In addition, a room temperature sensor 86 for detecting the temperature of the indoor air flowing into the indoor unit 8a, i.e., the room temperature, is provided near the indoor air intake (not shown) of the indoor unit 8a. Furthermore, a refrigerant sensor 80 for detecting refrigerant leakage is provided in the room where the indoor unit 8a is installed. The refrigerant sensor 80 is not limited to being installed on the indoor unit 8a, but may be placed in other locations in the room.

[0038] [Shut-off valve] The air conditioning system 100 further includes a liquid-side shut-off valve 11 as a first shut-off valve for blocking the flow of refrigerant in the liquid pipe 31, and a gas-side shut-off valve 12 as a second shut-off valve for blocking the flow of refrigerant in the gas pipe 32. Both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are electrically operated ball valves. When the air conditioning system 100 is in operation, the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are kept open by a control unit 90, which will be described later.

[0039] In this embodiment, the liquid-side shut-off valve 11 is located in the outdoor unit liquid pipe 35, more specifically in the liquid pipe 31, but is not limited to this, and may be located in the liquid branch pipe 71 connected to each indoor unit 8a to 8c, corresponding to each indoor unit 8a to 8c. On the other hand, the gas-side shut-off valve 12 is located in the gas pipe 32, but is not limited to this, and may be located in the outdoor unit gas pipe 34, or in the gas branch pipe 72 connected to each indoor unit 8a to 8c, corresponding to each indoor unit 8a to 8c.

[0040] Figure 2 is a schematic cross-sectional view showing one example of the configuration of the liquid-side shut-off valve 11, and Figure 3 is a schematic perspective view illustrating the operation of the liquid-side shut-off valve 11. In each figure, (A) shows the fully open state and (B) shows the fully closed state. Since the gas-side shut-off valve 12 has a similar structure, only the liquid-side shut-off valve 11 will be described here.

[0041] The liquid-side shut-off valve 11 is a valve device comprising a ball-shaped valve body 60 having a radially penetrating flow path portion 60a, a casing 61 having a valve chamber 610 that houses the valve body 60, and a drive unit 62 that rotates the valve body 60 within the valve chamber 610.

[0042] The casing 61 has a first connection port 61A connected to a first refrigerant pipe 31A that forms part of the liquid pipe 31, a second connection port 61B connected to a second refrigerant pipe 31B that forms another part of the liquid pipe 31, and a third connection port 61C connected to the drive unit 62. The first refrigerant pipe 31A is a refrigerant passage connecting the liquid-side shut-off valve 45 and the liquid-side shut-off valve 11, and the second refrigerant pipe 31B is a refrigerant passage connected between the liquid-side shut-off valve 11 and the liquid branch pipe 71.

[0043] The drive unit 62 includes a drive shaft 63 connected to the valve body 60, a motor 64, and a gear unit 65 that transmits the driving force of the motor 64 to the drive shaft 63. The drive shaft 63 is inserted through the third connection port 61C of the casing 61 as the rotation axis of the valve body 60. The motor 64 is a stepping motor having a rotor unit 641 and a stator unit (coil unit) 642. The gear unit 65 is a power transmission mechanism that transmits the rotational force of the motor 64 to the drive shaft 63, and is typically a gear assembly including a reduction gear.

[0044] The valve body 60 is rotatably supported inside the valve chamber 61 via a pair of annular ball seats 611. The valve chamber 610 is divided by the valve body 60 into a first space S1 communicating with the first connection port 61A and the second connection port 61B, which are on the refrigerant passage side, and a second space S2 communicating with the third connection port 61C, which is on the drive unit 62 side.

[0045] The valve body 60 can rotate between a position where the flow path portion 60a is aligned with the refrigerant passage (refrigerant pipes 31A, 31B) (fully open state), as shown in Figures 2(A) and 3(A), and a position where the flow path portion 60a is perpendicular to the refrigerant passage (refrigerant pipes 31A, 31B) (fully closed state), as shown in Figures 2(B) and 3(B), by the rotation of the drive shaft 63. The rotation angle of the valve body 60 is adjusted by the control unit 90, which will be described later.

[0046] [Shut-off valve] The liquid-side shut-off valve 45 connects the outdoor unit liquid pipe 35 and the liquid pipe 31. The outdoor unit liquid pipe 35 connects one end of the outdoor heat exchanger 24 (the other refrigerant inlet / outlet mentioned above) to the liquid-side shut-off valve 45, and the liquid pipe 31 connects one end of the indoor heat exchanger 81 (the one refrigerant inlet / outlet mentioned above) to the liquid-side shut-off valve 45. The liquid-side shut-off valve 45 is a three-way valve equipped with a service port PL for vacuuming the liquid pipe 31 and the outdoor unit liquid pipe 35.

[0047] Furthermore, the gas-side shut-off valve 46 connects the outdoor unit low-pressure gas pipe 34 to the gas pipe 32. The outdoor unit low-pressure gas pipe 34 connects the other end of the outdoor heat exchanger 24 (one of the refrigerant inlets and outlets mentioned above) to the gas-side shut-off valve 46 via the compressor 21, a four-way valve 22, etc., and the gas pipe 32 connects the other end of the indoor heat exchanger 81 (the other refrigerant inlet and outlet mentioned above) to the gas-side shut-off valve 46. The gas-side shut-off valve 46 is a three-way valve equipped with a service port PG for vacuuming the liquid pipe 31 and the outdoor unit liquid pipe 35.

[0048] [Control Unit] The air conditioning system 100 includes a control unit 90. The control unit 90 is, for example, an outdoor unit control device provided in the outdoor unit 2, and is mounted on a control board housed in an electrical component box (not shown) of the outdoor unit 2. The control unit 90 corresponds to the control unit in the present invention.

[0049] Figure 4 is a block diagram showing the configuration of the control unit 90. As shown in the figure, the control unit 90 includes a CPU 91, a storage unit 92, a communication unit 93, a sensor input unit 94, and a rotation speed detection unit 95.

[0050] The memory unit 92 is a non-volatile memory such as flash memory, and stores the control program and control parameters of the outdoor unit 2, detected values ​​corresponding to detection signals from various sensors, the control status of the compressor 21 and outdoor fan 26, the rotation speed of the indoor fan 83 acquired via the communication unit 93, and the control status of indoor units 8a to 8c, including the operating mode set by the user.

[0051] The communication unit 93 is an interface for communicating with the indoor units 8a to 8c. The sensor input unit 94 receives detection results from various sensors on the outdoor unit 2 and outputs them to the CPU 91. The rotation speed detection unit 95 detects the rotation speed of the compressor 21 motor and outputs it to the CPU 91. The rotation speed detection unit 95 may be configured to directly detect the rotation speed of the motor using an encoder or the like attached to the motor's drive shaft, or it may be configured to detect the rotation speed of the motor from the drive current supplied to the motor. In the following description, the rotation speed of the compressor 21 refers to the rotation speed of the motor.

[0052] The CPU 91 is a control unit that controls the operation of each part of the outdoor unit 2, including the compressor 21, by executing a program stored in the memory unit 92. The program is installed in the control unit 90, for example, via various recording media. Alternatively, the program may be installed via the internet or the like.

[0053] The CPU 91 receives the detection results from each sensor of the outdoor unit 2 via the sensor input unit 94. Furthermore, the CPU 91 receives control signals transmitted from the indoor units 8a to 8c via the communication unit 93. The control signals transmitted from the indoor units 8a to 8c include the required operating capacity (total heat load of indoor units 8a to 8c) requested by the indoor units 8a to 8c. Based on the received detection results and control signals, the CPU 91 controls the drive of the compressor 21, the outdoor fan 26, and the indoor fan 83, for example, by setting the indicated rotational speed, which is the rotational speed at which they are driven. The CPU 91 also controls the switching of the four-way valve 22 based on the received detection results and control signals. Furthermore, the CPU 91 controls the rotational speed of the compressor 21 and the outdoor fan 26, and controls the opening degree of the outdoor expansion valve 40, etc., based on the received detection results and control signals.

[0054] In this embodiment, the CPU 91 also controls the opening degree of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12. As described above, the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are ball valves, and the CPU 91 functions as a switching unit that generates control commands to switch the ball valve between, for example, the open state, intermediate state, and closed state shown in Figures 5(A) to (D). Figure 5 is a schematic cross-sectional view in the direction of the CC line in Figure 2(A), where (A) and (B) show the open state of the ball valve, (C) shows the intermediate state of the ball valve, and (D) shows the closed state (fully closed state) of the ball valve.

[0055] The open valve state shown in Figures 5(A) and 5(B) refers to a state in which the flow path portion 60a of the valve body 60 communicates only with the first space S1 and not with the second space S2. In particular, the state in Figure 5(A), where the refrigerant passage and the flow path portion 60a are aligned, corresponds to the fully open state of the ball valve. During operation of the air conditioning system 100, both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are basically in this fully open state.

[0056] The intermediate state shown in Figure 5(C) refers to the state in which the flow path 60a of the valve body 60 communicates with both the first space S1 and the second space S2. This intermediate state is set when the refrigerant circuit 10, which will be described later, is vacuumed. In the following description, the process by which the CPU 91 sets the valve body 60 to this intermediate state is also referred to as the first opening degree adjustment process. The process by which the CPU 91 sets the valve body 60 to the above open state is also referred to as the second opening degree adjustment process.

[0057] The closed valve state shown in Figure 5(D) refers to a state in which the flow path portion 60a of the valve body 60 communicates only with the second space S and not with the first space S1. For example, as will be described later, when a refrigerant leak is detected by the refrigerant sensor 80, the control unit 90 switches both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 from the open state (fully open state) to this closed valve state.

[0058] The detection signal from the refrigerant sensor 80 may be input to the CPU 91 via the sensor input unit 94, or it may be transmitted to the CPU 91 via the indoor units 8a to 8c. In this case, the detection signal from the refrigerant sensor 80 may be included in the control signals transmitted from the indoor units 8a to 8c.

[0059] [Refrigerant circuit operation] Next, the flow of refrigerant in the refrigerant circuit 10 and the operation of each part during air conditioning operation of the air conditioning system 100 in this embodiment will be explained using Figure 1. When the air conditioning system 100 is in operation, both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are in the open state (fully open state).

[0060] (Air conditioning operation) When the air conditioning system 100 is in cooling operation, the four-way valve 22 of the outdoor unit 2 is switched so that port a and port b are connected, and port c and port d are connected (shown by dashed lines in Figure 1), thereby causing the outdoor heat exchanger 24 to function as a condenser.

[0061] The high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 28 into the four-way valve 22. The refrigerant flowing out of the four-way valve 22 flows through the refrigerant pipe 37 into the outdoor heat exchanger 24, where it exchanges heat with the outside air and condenses. The refrigerant condensed in the outdoor heat exchanger 24 passes through the outdoor expansion valve 40 and flows into the liquid pipe 31 via the liquid side shut-off valve 45 and the liquid side shut-off valve 11. The refrigerant flowing into the liquid pipe 31 is divided and flows into each indoor unit 8a to 8c by the liquid branch pipe 71.

[0062] The refrigerant flowing into each indoor unit 8a to 8c is depressurized by the indoor expansion valve 82 to become low-pressure refrigerant, which then flows into the indoor heat exchanger 81. The low-pressure refrigerant flowing into the indoor heat exchanger 81 exchanges heat with the indoor air and evaporates, thereby cooling the room where the indoor units 8a to 8c are installed.

[0063] The low-pressure refrigerant that flows out from the indoor heat exchanger 81 flows into the gas pipe 32 through the gas branch pipe 72, and then into the outdoor unit 2 through the gas-side shut-off valve 12 and the gas-side closing valve 46. The low-pressure refrigerant that flows into the outdoor unit 2 passes through the outdoor unit gas pipe 34, and is drawn into the compressor 21 via the four-way valve 22 and the accumulator 27, where it is compressed again.

[0064] (Heating operation) When the air conditioning system 100 is operating in heating mode, the four-way valve 22 of the outdoor unit 2 is switched so that port a and port d are connected and port b and port c are connected (shown by a solid line in Figure 1), thereby causing the outdoor heat exchanger 24 to function as an evaporator.

[0065] The high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 28 into the four-way valve 22. The refrigerant flowing out of the four-way valve 22 flows through the outdoor unit gas pipe 34 and into the gas pipe 32 via the gas-side shut-off valve 46. The high-pressure refrigerant flowing into the gas pipe 32 flows into the indoor units 8a to 8c through the gas-side shut-off valve 12 and the gas branch pipe 72.

[0066] The high-pressure refrigerant flowing into each indoor unit 8a to 8c flows into the indoor heat exchanger 81, where it exchanges heat with the indoor air and condenses. This warms the indoor air, heating the room where the indoor units 8a to 8c are installed. The high-pressure refrigerant flowing out of the indoor heat exchanger 81 passes through the indoor expansion valve 82 and is depressurized. The degree of subcooling of the refrigerant can be determined, for example, by subtracting the refrigerant temperature at the refrigerant outlet of the indoor heat exchanger 81, detected by the refrigerant temperature sensor 84, from the high-pressure saturation temperature (corresponding to the condensation temperature inside the indoor heat exchanger 81), which is calculated from the pressure detected by the high-pressure sensor 50 of the outdoor unit 2.

[0067] The refrigerant discharged from each indoor unit 8a to 8c flows into the liquid pipe 31 through the liquid branch pipe 71, and then into the outdoor unit 2 via the liquid side shut-off valve 11 and the liquid side closing valve 45. The intermediate-pressure refrigerant that flows into the outdoor unit 2 flows through the outdoor unit liquid pipe 35, passes through the outdoor expansion valve 40, and is depressurized to become low-pressure refrigerant. The degree of superheating of the refrigerant can be determined, for example, by subtracting the low-pressure saturation temperature (corresponding to the evaporation temperature in the outdoor heat exchanger), which is calculated from the pressure detected by the low-pressure sensor 51 of the outdoor unit 2, from the refrigerant temperature in the outdoor heat exchanger 24 detected by the heat exchanger temperature sensor 56.

[0068] The low-pressure refrigerant, reduced in pressure by the outdoor expansion valve 40, flows into the outdoor heat exchanger 24, where it exchanges heat with the outside air and evaporates. The low-pressure refrigerant that flows out of the outdoor heat exchanger 24 is then drawn into the compressor 21 via the four-way valve 22 and the accumulator 27 and compressed again.

[0069] [Installation of air conditioning system] (Basic procedure) Next, we will explain the installation procedure for the air conditioner 100. The installation procedure for the air conditioner 100 is basically carried out in the following steps.

[0070] After installing the outdoor unit 2 and each of the indoor units 8a to 8c in their respective designated locations, the refrigerant circuit 10 is formed by connecting the indoor heat exchangers 81 of the outdoor unit 2 and each of the indoor units 8a to 8c with the liquid pipe 31, liquid branch pipe 71, gas branch pipe 72, and gas pipe 32. The liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are connected to the liquid pipe 31 and the gas pipe 32 (or the liquid branch pipe 71 and the gas branch pipe 72), respectively. Hereinafter, the refrigerant flow path outside the outdoor unit 2, which is formed by the liquid pipe 31, liquid branch pipe 71, gas branch pipe 72, gas pipe 32 and the indoor heat exchanger 81 and connected to the liquid-side shut-off valve 45 and the gas-side shut-off valve 46, will also be referred to as the external refrigerant flow path.

[0071] Next, an airtightness test is performed to confirm the airtightness of the external refrigerant flow path. In this airtightness test, nitrogen gas at a pressure exceeding atmospheric pressure is injected from the service ports PL and PG of the liquid-side shut-off valve 45 and the gas-side shut-off valve 46, respectively, to check for any leakage of nitrogen gas from the refrigerant piping.

[0072] During the installation of the air conditioner 100, both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are set to the open state (normally fully open). Also, during the installation of the outdoor unit 2 (at the time of shipment), both the liquid-side shut-off valve 45 and the gas-side shut-off valve 46 are set to the closed state. Nitrogen gas is injected into the external refrigerant flow path from the service port PL of the liquid-side shut-off valve 45 or the service port PG of the gas-side shut-off valve 46. Note that the refrigerant piping formed inside the outdoor unit 2 of the refrigerant circuit 10 is closed by the liquid-side shut-off valve 45 and the gas-side shut-off valve 46, so nitrogen gas is not injected into the refrigerant piping formed inside the outdoor unit 2.

[0073] If the airtightness test reveals a nitrogen gas leak from the external refrigerant flow path, the leaking refrigerant piping and its connections are repaired, and then the airtightness test is repeated. On the other hand, if it is confirmed that there is no nitrogen gas leak, the airtightness test is terminated, and nitrogen gas is discharged (purged) from the service port PL of the liquid-side shut-off valve 45 and the service port PG of the gas-side shut-off valve 46.

[0074] Next, the external refrigerant flow path is evacuated from the service port PL of the liquid-side shut-off valve 45 or the service port PG of the gas-side shut-off valve 46. Specifically, a vacuum pump (not shown) is connected to the service port PL of the liquid-side shut-off valve 45 or the service port PG of the gas-side shut-off valve 46, and this vacuum pump is operated to reduce the pressure in the external refrigerant flow path to below a predetermined pressure. The predetermined pressure is not particularly limited as long as it is a pressure that can remove air from the external refrigerant flow path and does not affect the operation of the air conditioner.

[0075] Next, refrigerant is filled into the external refrigerant flow path from the service port PL of the liquid-side shut-off valve 45 or the service port PG of the gas-side shut-off valve 46. After the refrigerant filling is complete, the liquid-side shut-off valve 45 and the gas-side shut-off valve 46 are opened to fill the refrigerant circuit of the outdoor unit 2 with refrigerant. Since the inside of the outdoor unit 2 is already filled with a predetermined amount of refrigerant, the necessary amount of refrigerant is filled here, which is determined by the diameter and length of the refrigerant piping connecting the outdoor unit 2 and the indoor units 8a to 8c.

[0076] In this case, when the ball valve is in the open (fully open) state, a space (dead space) may be created where air cannot be drawn in during vacuuming of the refrigerant circuit. For example, when the ball valve shown in Figures 5(A) and (B) is in the open state, the second space S2, which is isolated from the refrigerant flow path by the valve body 60 and the ball seat 611, and the inside of the drive unit 62 that communicates with this second space S2 correspond to the dead space. Therefore, when a ball valve is used as a shut-off valve, if the shut-off valve is opened and closed to check its operation after vacuuming the refrigerant circuit or filling the refrigerant, air from the dead space will be mixed into the refrigerant circuit. As a result, for example, if air flows into the condenser that forms the refrigerant circuit, the heat exchange (liquefaction) of the refrigerant in the condenser may be hindered during air conditioning operation, causing the condensation pressure to rise. This may increase the load on the compressor and worsen the air conditioning performance. In addition, the rise in condensation pressure makes the compressor's high-pressure protection control more likely to activate, which may lead to frequent starting and stopping of the compressor and a reduction in the compressor's lifespan.

[0077] To resolve these issues, in this embodiment, when evacuating the refrigerant circuit, the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are controlled as follows to prevent air from entering the refrigerant circuit. The details are described below.

[0078] (Vacuuming method for the refrigerant circuit in this embodiment) In this embodiment, when evacuating the refrigerant circuit 10 during the installation of the air conditioning system 100, the control unit 90 performs a process to set the opening degrees of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 to at least an intermediate state as shown in Figure 5(C) (hereinafter also referred to as the first opening degree adjustment process). This enables evacuating of the second space S2, thereby preventing air from entering the refrigerant circuit 10 after refrigerant charging.

[0079] (Step 1) Figure 6 is a process flow showing an example of the procedure for adjusting the opening degrees of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 during the vacuuming process of the refrigerant circuit.

[0080] When vacuuming of the refrigerant circuit 10 is started, first, both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are opened (second opening degree adjustment process, ST101). Since both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are already open in the airtightness test process performed before vacuuming, this ST101 process may be omitted. Alternatively, if the control unit 90 consistently adjusts the opening degrees of the shut-off valves 11 and 12 during the vacuuming process, this ST101 process may be always performed.

[0081] Figure 7 is a conceptual diagram illustrating the vacuuming process of the refrigerant circuit 10. Here, an example is shown in which a vacuum pump 65 is connected to the service port PL of the liquid-side shut-off valve 45, and a pressure sensor 66 is pre-connected to a part of the liquid pipe 31. The vacuum pump 65 is started by the operator's operation and exhausts the external refrigerant flow path (discharges the air in the external refrigerant flow path). At this time, the opening degree of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is not limited to the fully open state shown in Figure 5(A), but may be in an open state with a smaller opening degree than the fully open state shown in Figure 5(B). However, a larger opening degree reduces the resistance of the air flowing through the shut-off valve, which shortens the exhaust time, so a fully open state is preferable from the viewpoint of shortening the work time.

[0082] When the pressure in the external refrigerant flow path falls below a predetermined pressure (Yes in ST102), the control unit 90 switches the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 from the open state (fully open state) shown in Figure 5(A) to the intermediate state shown in Figure 5(C) (first opening degree adjustment process, ST103). As a result, the second space S2 within the casing 61 of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 communicates with the external refrigerant flow path via the first space S1, and the second space S2 is exhausted (pressure reduced).

[0083] In this embodiment, the value detected by the pressure sensor 66 is input to the control unit 90, and when the control unit 90 determines that the value detected by the pressure sensor 66 has reached or below the predetermined pressure, it executes a first opening degree adjustment process to set the opening degrees of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 to an intermediate state. Alternatively, the operator may read the value detected by the pressure sensor 66 and cause the control unit 90 to perform an input operation to execute the first opening degree adjustment process when that value reaches or below the predetermined pressure.

[0084] Furthermore, the opening degree of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 in the intermediate state is not particularly limited as long as the opening degree allows the second space S2 to communicate with the first space S1, as shown in Figure 5(C). For example, as shown in Figure 8, when the angle between the flow direction of the refrigerant flowing through the refrigerant passage (liquid pipe 31, gas pipe 32) and the axial direction of the flow path portion 60a of the valve body 60 is 0° when fully open and 90° when fully closed, the angle in the intermediate state is set to, for example, the angle range shown in Figures 5(B) to 5(D) (for example, 20° to 70°).

[0085] By switching the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 to an intermediate state, the air remaining in the second space S2 flows out into the refrigerant passage, which may cause the pressure in the external refrigerant flow path to temporarily rise to a pressure exceeding the predetermined pressure. Since the vacuum pump 65 continues to operate, the pressure in the external refrigerant flow path will return to below the predetermined pressure.

[0086] Therefore, after switching to the intermediate state, the control unit 90 determines again whether the value detected by the pressure sensor 66 has reached or below the predetermined pressure (ST104). If the value detected by the pressure sensor 66 has reached or below the predetermined pressure, the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is switched back to the fully open state (second opening adjustment process, ST105). This sets the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 to the opening required for the next step, the refrigerant charging step.

[0087] In the above description, the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is switched from an intermediate state to a fully open state based on the detected value of the pressure sensor 66. However, the description is not limited to this, and the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 may be switched from an intermediate state to a fully open state based on whether or not the vacuuming operation has continued for a certain period of time. Similarly, in the ST102 process, the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 may be switched from a fully open state to an intermediate state based on whether or not the vacuuming operation has continued for a certain period of time.

[0088] Furthermore, a temporary power source such as a generator can be used to power the vacuum pump. This temporary power source may also be used to power the control unit 90 that generates control signals to drive the liquid-side shut-off valve 11 and the gas-side shut-off valve 12.

[0089] As described above, according to this embodiment, the vacuuming process of the refrigerant circuit 10 (external refrigerant flow path) performed when installing the air conditioning system 100 includes a process to switch the opening degree of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 to an intermediate state. This prevents air from being mixed into the refrigerant circuit 10, which may occur due to the use of ball valves. This prevents deterioration of air conditioning performance and frequent high-pressure protection control of the compressor caused by the rise in condensation pressure due to the mixing of air into the condenser during air conditioning operation.

[0090] (Step 2) Figure 9 is a process flow showing another example of the procedure for adjusting the opening degrees of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 during the vacuuming process of the refrigerant circuit. This example differs from procedure 1 described above in that the initial opening degrees of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 when vacuuming of the external refrigerant flow path is started are in an intermediate state.

[0091] As shown in Figure 9, when vacuuming of the refrigerant circuit 10 is started, first, both the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are set to an intermediate state (first opening adjustment process, ST201). Subsequently, the vacuum pump 65 is started by the operator and the external refrigerant passage is exhausted. Since the second space S2 of each of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is in communication with the refrigerant passage (liquid pipe 31, gas pipe 32) via the first space S1, these second spaces S2 are also exhausted along with the refrigerant passage.

[0092] The control unit 90 determines whether the value detected by the pressure sensor 66 has reached or below the predetermined pressure (ST202). If the value detected by the pressure sensor 66 has reached or below the predetermined pressure, the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is switched to the fully open state (second opening adjustment process, ST203). This sets the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 to the opening required for the next step, the refrigerant charging step.

[0093] In the above description, the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is switched from an intermediate state to a fully open state based on whether the detected value of the pressure sensor 66 has reached or below a predetermined pressure. However, the description is not limited to this, and the opening of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 may be switched from an intermediate state to a fully open state based on whether the vacuuming operation has continued for a certain period of time or longer.

[0094] In this example, the same effects and advantages as described above can be obtained. According to this example, the number of adjustments required for the opening degrees of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is less than in procedure 1, thus simplifying the vacuuming process. Furthermore, procedure 2 can be adopted when using ball valves whose initial opening degree at the time of shipment is the intermediate state described above as the liquid-side shut-off valve 11 and the gas-side shut-off valve 12.

[0095] Although embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the embodiments described above and can be modified in various ways.

[0096] For example, in the above embodiment, an example was described in which the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 are arranged in the liquid pipe 31 and the gas pipe 32, respectively, but it is not limited to this. For example, as in the air conditioning system 200 shown in Figure 10, the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 may be arranged in the liquid branch pipe 71 and the gas branch pipe 72, respectively, corresponding to each indoor unit 8a to 8c. Generally, the more indoor units there are, the more refrigerant is filled into the refrigerant circuit 10. Therefore, by closing the shut-off valve closest to the indoor unit in which refrigerant leakage is detected, the amount of refrigerant that leaks can be reduced compared to the case where a common shut-off valve is installed for each indoor unit.

[0097] Furthermore, although the above embodiments have described an air conditioning system in which ball valves are used for the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 as an example, the present invention is also applicable to air conditioning systems in which ball valves are used for other flow control valves, such as on-off valves for flow path switching.

[0098] Furthermore, in the embodiments described above, an example was described in which a switching unit (CPU91) for switching the opening degrees of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12 is mounted on the outdoor unit 2. However, the invention is not limited to this, and the switching unit may be mounted on each of the liquid-side shut-off valve 11 and the gas-side shut-off valve 12. In this case as well, the same effects and advantages as described above can be obtained. [Explanation of Symbols]

[0099] 2…Outdoor unit 8a~8c…Indoor unit 10... Refrigerant passage 11…Liquid-side shut-off valve 12... Gas-side shut-off valve 21... Compressor 22... Four-way valve 24…Outdoor heat exchanger 31… Liquid tube 32... Gas pipe 40... Outdoor expansion valve 60… Valve body 60a...Flow channel section 61…Casing 62…Drive unit 65… Vacuum pump 66... ​​Pressure sensor 71... Liquid branch pipe 72...Gas branch pipe 80... Refrigerant sensor 81…Indoor heat exchanger 90... Control Unit 100,200... Air conditioning systems 610... Valve chamber S1...first space part S2…Second space part

Claims

1. A refrigerant circuit having an outdoor unit having a compressor and an outdoor heat exchanger, an indoor unit having an indoor heat exchanger, and a refrigerant passage connecting the outdoor unit and the indoor unit, A ball valve provided in the refrigerant passage, The system comprises a control unit for controlling the ball valve, The ball valve comprises a ball-shaped valve body having a radially penetrating flow path, a valve chamber housing the valve body, and a drive unit for rotating the valve body within the valve chamber, wherein the valve chamber is divided by the valve body into a first space communicating with the refrigerant passage and a second space communicating with the drive unit. The control unit, The ball valve is controlled so as to be switchable between an open state in which the flow path communicates only with the first space, a closed state in which the flow path communicates only with the second space, and an intermediate state in which the flow path communicates with both the first and second spaces. When the refrigerant circuit is evacuated, a first opening degree adjustment process is performed, which sets the ball valve to the intermediate state. Air conditioning system.

2. An air conditioning device according to claim 1, When vacuuming of the refrigerant circuit is started, the control unit performs a second opening adjustment process, which sets the ball valve to the open state, before performing the first opening adjustment process. When the pressure in the refrigerant circuit reaches below a predetermined value due to vacuuming in the open state, the control unit performs the first opening adjustment process. Air conditioning system.

3. An air conditioning device according to claim 2, When the control unit performs the vacuuming in the intermediate state and the pressure in the refrigerant circuit falls below the predetermined value, it executes the second opening degree adjustment process. Air conditioning system.

4. An air conditioning device according to claim 2 or 3, The aforementioned open state is the fully open state of the ball valve. Air conditioning system.

5. An air conditioning device according to claim 1, The control unit executes the first opening adjustment process when vacuuming of the refrigerant circuit is started, and when the pressure of the refrigerant circuit reaches below a predetermined value due to the vacuuming performed in the intermediate state, it executes a second opening adjustment process, which sets the ball valve to the open state. Air conditioning system.

6. An air conditioning device according to claim 1, The ball valve is a shut-off valve capable of blocking the flow of refrigerant in the refrigerant passage. Air conditioning system.

7. An air conditioning device according to claim 6, The refrigerant passage includes a gas pipe through which gaseous refrigerant flows and a liquid pipe through which liquid refrigerant flows. The shut-off valves are arranged in the gas pipe and the liquid pipe, respectively. Air conditioning system.

8. An air conditioning device according to claim 1, The control unit has a switching unit that generates a control command to switch the ball valve between the open state and the intermediate state when it determines that the detected value of the pressure sensor that detects the pressure in the refrigerant passage has reached a predetermined pressure or less. Air conditioning system.

9. An air conditioning device according to claim 8, The switching unit is mounted on the outdoor unit or the ball valve. Air conditioning system.

10. A refrigerant circuit having an outdoor unit having a compressor and an outdoor heat exchanger, an indoor unit having an indoor heat exchanger, and a refrigerant passage connecting the outdoor unit and the indoor unit, A ball valve provided in the refrigerant passage, A method for installing an air conditioning system, comprising: The ball valve comprises a ball-shaped valve body having a radially penetrating flow path, a valve chamber housing the valve body, and a drive unit for rotating the valve body within the valve chamber, wherein the valve chamber is divided by the valve body into a first space communicating with the refrigerant passage and a second space communicating with the drive unit. When evacuating the refrigerant circuit, A vacuum pump is connected to the aforementioned refrigerant passage. The ball valve is set to an intermediate state in which the flow path is in communication with both the first space and the second space, and the vacuum pump is used to evacuate the refrigerant circuit and the second space, at least including this step. Installation method for air conditioning systems.

Images