Refrigerant recovery system and method

Abstract

The first recovery device (16) recovers the compressed and condensed refrigerant generated by compressing and condensing the air-conditioning refrigerant. The adsorption device (418) includes an adsorption module (468). The adsorption module (468) has an adsorbent (350) that adsorbs the gas component (423) of the air-conditioning refrigerant in the mixed gas (22) composed of the gas component (423) of the air-conditioning refrigerant and the non-condensable gas (26) contained in the inside of the first recovery device (16) that recovered the compressed and condensed refrigerant. The desorption device (19) desorbs the gas component (423) of the air-conditioning refrigerant adsorbed to the adsorbent (350) and accumulates the desorbed gas component (423) of the air-conditioning refrigerant.

Description

Technical Field

[0001] This invention relates to a refrigerant recovery system and a refrigerant recovery method. Background Technology

[0002] Refrigeration and air conditioning equipment (refrigerant-using equipment) includes the following components in the refrigerant circulation path for transporting heat energy: an air conditioning compressor, which compresses the vaporized refrigerant gaseous refrigerant to a high temperature and pressure; an air conditioning condenser, which uses outside air to cool the vaporized refrigerant gaseous refrigerant from the air conditioning compressor to liquefy it; an expansion valve, which causes the refrigerant (liquid refrigerant) liquefied in the air conditioning condenser to expand and vaporize; a refrigerant recovery condenser, which liquefies the refrigerant (gaseous refrigerant) vaporized in the expansion valve; and a receiver, which stores the refrigerant (liquid refrigerant) liquefied in the refrigerant recovery condenser. The refrigerant plays a role in transporting heat energy, releasing heat to the outside in the air conditioning condenser and receiving heat from outside air after passing through the expansion valve.

[0003] The release of various refrigerants used in refrigeration and air conditioning equipment into the atmosphere is limited due to the high coefficients of global warming and ozone layer depletion. Therefore, especially when changing refrigerants or when maintaining or disposing of refrigeration and air conditioning equipment, it is imperative to recover the refrigerant stored in the equipment without releasing it into the atmosphere. Simultaneously, there is a growing trend towards refrigerants with lower environmental impact. In recent years, HFCs (hydrofluorocarbons) have become mainstream as alternatives to Freon. Examples of HFCs include, for instance, R134A or R32 (also referred to as "R-32") as single refrigerants, and R410A or R407C as mixed refrigerants.

[0004] Refrigerant recovery is performed using a refrigerant recovery unit. In this unit, the refrigerant present in the refrigerant circuit (including the receiver) within the refrigeration and air conditioning equipment is vaporized. The vaporized refrigerant is then drawn in by a compressor within the unit and adiabatically compressed. The compressed vaporized refrigerant is then liquefied by a condenser within the unit and recovered as liquid refrigerant into a recovery tank. The amount of refrigerant recovered is measured using a weighing scale.

[0005] When refrigerant is recovered from refrigerant-using equipment to a recovery tank via a refrigerant recovery device, if non-condensable gases such as nitrogen (N2) and oxygen (O2), which are primarily composed of air, are mixed into the recovery system, there is a problem that these non-condensable gases will also be recovered to the recovery tank. These non-condensable gases exist as compressed gases in the recovery tank without condensing. Therefore, as the amount of liquid refrigerant in the recovery tank increases and the volume of the gas phase decreases, the pressure and temperature inside the recovery tank rise. As a result, the internal pressure of the recovery tank increases, making it difficult to fill with liquid refrigerant and slowing down the rate of refrigerant recovery. Consequently, a significant amount of time is spent recovering all the refrigerant.

[0006] To address this problem, the refrigerant recovery system in Patent Document 1 is configured to include a gas separation module that separates the gaseous refrigerant and the mixture of non-condensable gases stored in the recovery tank. The mixture in the recovery tank is fed to the gas separation module for separation, the separated non-condensable gases are discharged into the atmosphere, and the gaseous refrigerant is then sent to the refrigerant recovery device. Thus, in the refrigerant recovery system of Patent Document 1, while maintaining the connection between the recovery tank, the refrigerant recovery device, and the refrigeration and air conditioning equipment, the amount of non-condensable gas in the recovery tank is reduced.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 7029025 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] However, when using the refrigerant recovery system of Patent Document 1, there is a difficulty in separating the mixed gas contained in the recovery equipment (recovery tank) into non-condensable gas and gaseous refrigerant through the gas separation module. This is because, for example, when using R32 as the refrigerant, it is sometimes impossible to completely separate it into non-condensable gas and R32 through the gas separation module.

[0012] Therefore, the object of the present invention is to provide a refrigerant recovery system and a refrigerant recovery method that can reduce non-condensable gases in the recovery equipment and appropriately separate the gases contained in the recovery equipment into non-condensable gases and gaseous refrigerants.

[0013] means for solving problems

[0014] The refrigerant recovery system of the present invention is a system for recovering refrigerant for air conditioning from the refrigerant circuit of a refrigeration and air conditioning equipment. The refrigerant recovery system includes a first recovery device, an adsorption device, and a desorption device. The first recovery device recovers compressed and condensed refrigerant generated by compressing and condensing the air conditioning refrigerant. The adsorption device includes an adsorption module. The adsorption module has an adsorbent that adsorbs the gaseous components of the air conditioning refrigerant contained within the first recovery device, which contains gaseous components of the air conditioning refrigerant and non-condensable gases. The desorption device desorbs the gaseous components of the air conditioning refrigerant adsorbed on the adsorbent and accumulates the desorbed gaseous components of the air conditioning refrigerant.

[0015] The refrigerant recovery method of the present invention is a method for recovering air conditioning refrigerant from the refrigerant circuit of a refrigeration and air conditioning equipment. The refrigerant recovery method includes the following steps: a first recovery device recovers compressed and condensed refrigerant generated by compressing and condensing air conditioning refrigerant; the adsorbent of the adsorption module of the adsorption device adsorbs the gaseous components of air conditioning refrigerant contained in the mixed gas of the first recovery device containing the gaseous components of air conditioning refrigerant and non-condensable gases, which has recovered the compressed and condensed refrigerant; and a desorption device desorbs the gaseous components of air conditioning refrigerant adsorbed on the adsorbent and accumulates the desorbed gaseous components of air conditioning refrigerant.

[0016] The effects of the invention

[0017] According to the present invention, it is possible to reduce the amount of non-condensable gas in the recovery equipment and to properly separate the gas contained in the recovery equipment into non-condensable gas and gaseous refrigerant. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the refrigerant recovery system 10B according to Embodiment 1.

[0019] Figure 2 This is a block diagram of the sending controller 76.

[0020] Figure 3 This is a diagram showing examples of the pressure characteristics of various refrigerants.

[0021] Figure 4 This is a block diagram of the three-way valve controller 80.

[0022] Figure 5 This is a block diagram of the pressure controller 97A.

[0023] Figure 6 This is a diagram used to illustrate the set pressure PA of the internal and external differential pressure of the separation membrane 92A.

[0024] Figure 7This is a schematic diagram illustrating the principle of a molecular sieve, 92A, which is composed of an inorganic separation membrane.

[0025] Figure 8 This is a diagram showing the details of the first adsorption unit 321, the second adsorption unit 322, and the third adsorption unit 323.

[0026] Figure 9 This is a diagram showing an example of refrigerant being adsorbed by adsorbent 350.

[0027] Figure 10 This is another example of refrigerant being adsorbed by adsorbent 350.

[0028] Figure 11 This is a graph showing the relationship between vacuum level and the adsorption rate of R-32 on zeolite.

[0029] Figure 12 This is a graph showing the relationship between vacuum level and the desorption rate of R-32 on zeolite.

[0030] Figure 13 This is a graph showing the shift in the outlet concentration of R-32 in the adsorption and desorption processes.

[0031] Figure 14 This is a flowchart illustrating a specific refrigerant recovery method using the refrigerant recovery system 10B in Embodiment 1.

[0032] Figure 15 This is a flowchart illustrating a specific refrigerant recovery method using the refrigerant recovery system 10B in Embodiment 1.

[0033] Figure 16 This is a flowchart showing the control of the first three-way valve.

[0034] Figure 17 This is a flowchart showing the control of the second three-way valve.

[0035] Figure 18 This is a schematic diagram of the refrigerant recovery system 10 according to Embodiment 2.

[0036] Figure 19 This is a flowchart illustrating a specific refrigerant recovery method using the refrigerant recovery system 10 in Embodiment 2.

[0037] Figure 20 This is a flowchart illustrating the processing steps of the adsorption process.

[0038] Figure 21 This is a flowchart illustrating the processing steps of the desorption process.

[0039] Figure 22This is a schematic diagram of the refrigerant recovery system 10A according to Embodiment 3.

[0040] Figure 23 This is a flowchart illustrating a specific refrigerant recovery method using the refrigerant recovery system 10A in Embodiment 3. Detailed Implementation

[0041] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The structures described below are illustrative examples and can be appropriately modified according to the specifications of the system, device, etc. Furthermore, in cases where multiple embodiments or modifications are included, it is initially envisioned that these feature parts be appropriately combined. In all the drawings, the same reference numerals are used to denote the same elements, and repeated descriptions are omitted.

[0042] Implementation method 1.

[0043] Figure 1 This is a schematic diagram of the refrigerant recovery system 10B according to Embodiment 1. In the diagram, solid lines represent piping for fluid flow, and dashed lines represent control lines for input and output to each controller.

[0044] The refrigerant recovery system 10B is a system for recovering refrigerant for air conditioning from refrigeration and air conditioning equipment and filling it into the recovery storage tank 16. Furthermore, as described later, the refrigerant recovery system 10B has the following function: it adsorbs the gaseous components of the refrigerant for air conditioning contained in the mixed gas stored inside the recovery storage tank 16 onto the adsorbent 350 of the separation device (also called the "adsorption device") 18; and then, through the desorption device 19, it desorbs the gaseous components of the refrigerant for air conditioning adsorbed onto the adsorbent 350 and recovers them again into the recovery storage tank 16.

[0045] The following description illustrates an example of recovering refrigerant for air conditioning from an air conditioning unit 12, which is a refrigeration and air conditioning device. However, the refrigerant recovery system 10B can be applied to the refrigerant recovery of all devices that use refrigerant. When the refrigeration and air conditioning device is in operation, the refrigerant for air conditioning transfers heat energy and undergoes a phase change between the liquid and gas phases, thereby achieving at least one of the cooling and heating functions of the air in the refrigeration and air conditioning device.

[0046] The refrigerant recovery system 10B includes a refrigerant recovery device 14, a recovery storage tank 16 as the first recovery device, a gas separation device 68, recharge pipes 58A to 58C as the first to third recharge pipes, and three-way valves 40 and 402.

[0047] The refrigerant recovery device 14 draws refrigerant from the refrigerant circuit 30 of the air conditioning unit 12 and performs adiabatic compression, causing the compressed refrigerant to condense and liquefy to generate compressed condensed refrigerant. The recovery storage tank 16 recovers the compressed condensed refrigerant generated by the refrigerant recovery device 14.

[0048] The gas separation device 68 separates the mixed gas 22, consisting of gaseous components of air conditioning refrigerant and non-condensable gases, contained inside the recovery storage tank 16, which has recovered compressed and condensed refrigerant, into multiple components. The gas separation device 68 includes a gas separation module 68A and an adsorption module 68B. The gas separation device 68 is also referred to as a separation device 18 or an adsorption device 18. Furthermore, a desorption device 19 is constructed comprising the refrigerant recovery device 14 and the recovery storage tank 16.

[0049] The reason for using the gas separation module 68A and the adsorption module 68B is that sometimes it is not possible to completely separate the refrigerant and non-condensable gases for air conditioning using only one module.

[0050] The gas components separated by the gas separation module 68A are then sent back to the refrigerant circuit 30 and the refrigerant recovery device 14 via piping 58A and 58C. In the vaporization promotion mode, the gas components separated by the gas separation module 68A are transported to the refrigerant circuit 30. This increases the temperature of the refrigerant in the refrigerant circuit 30, promoting refrigerant vaporization and increasing the refrigerant recovery speed when restarting. In the circulation mode, the gas components separated by the gas separation module 68A are transported to the refrigerant recovery device 14. This recycles the gas components of the air conditioning refrigerant separated by the gas separation module 68A.

[0051] A three-way valve 40 is disposed between the refrigerant circuit 30 and the refrigerant recovery device 14. The air conditioning unit 12 includes a maintenance port 34 connected to the refrigerant circuit 30.

[0052] The refrigerant circuit 30 includes a receiver 32 containing liquid refrigerant. The refrigerant recovery device 14 draws in gaseous refrigerant, which has been vaporized from the liquid refrigerant in the receiver 32, via a maintenance port 34.

[0053] The refrigerant recovery unit 14 includes a compressor and a condenser, and can be implemented using a widely available Freon recovery machine. The refrigerant recovery unit 14 includes an inlet 36 (inlet) for taking in air conditioning refrigerant from the refrigerant circuit 30, an outlet 38 for discharging compressed and condensed refrigerant, and a pressure detector 37 for detecting the pressure of the air conditioning refrigerant at the inlet 36.

[0054] The recovery tank 16 includes a liquid inlet / outlet 46 for introducing compressed and condensed refrigerant from the refrigerant recovery unit 14 into the recovery tank 16 and a gas inlet / outlet 48 for discharging the mixed gas 22 from the recovery tank 16. A mixture of non-condensable gas and refrigerant gas regasified to its gaseous volume is retained in the top space of the recovery tank 16.

[0055] The three-way valve 40 includes a first port 41, a second port 42, and a third port 43. The maintenance port 34 of the air conditioning unit 12 is connected to the first port 41 of the three-way valve 40 via a connecting pipe 50. The second port 42 of the three-way valve 40 is connected to the inlet 36 of the refrigerant recovery unit 14 via a front pipe 52. The third port 43 of the three-way valve 40 is connected to the recharge pipe 58C.

[0056] The outlet 38 of the refrigerant recovery unit 14 and the liquid inlet / outlet 46 of the recovery storage tank 16 are connected by a downstream piping 54. During normal refrigerant recovery, the first port 41 and the second port 42 of the three-way valve 40 are connected (normal mode).

[0057] Due to valve malfunction, piping corrosion, refrigerant decomposition, and air intrusion during refrigerant repairs, non-condensable gases, primarily composed of nitrogen or air (nitrogen, oxygen, etc.), sometimes mix into the air conditioning refrigerant (hereinafter referred to as refrigerant) of the air conditioning unit 12. During refrigerant recovery, when the non-condensable gas is drawn to the refrigerant recovery device 14 along with the refrigerant, it does not condense in the device but remains in a gaseous state as it fills the recovery tank 16. As a result, the internal pressure of the recovery tank 16 increases, making it difficult to fill with liquid refrigerant and reducing the rate of refrigerant recovery to the tank 16.

[0058] To address this situation, the refrigerant recovery system 10B includes: a separation device (adsorption device) 18, which removes non-condensable gases from the recovery tank 16 and adsorbs the second gaseous component 25 of the air conditioning refrigerant onto the adsorption section 315; and a desorption device 19, which desorbs the adsorbed second gaseous component 25 of the air conditioning refrigerant and recovers it. A mixed gas 22 is generated within the recovery tank 16. This mixed gas 22 is a mixture of non-condensable gases and a portion of the liquid refrigerant that has been re-vaporized relative to the volume of the non-condensable gases.

[0059] The separation device 18 also includes a gas inlet 60 and a delivery pipe 56. The gas inlet 60 is connected to the gas inlet 48 of the recovery tank 16. The gas inlet 60 extracts the mixed gas 22 that remains in the top space of the recovery tank 16. The mixed gas 22 taken in from the gas inlet 60 flows in the delivery pipe 56.

[0060] Gas separation unit 68 (separation unit 18) separates the air conditioning refrigerant as a gaseous component from the mixed gas 22 inside the recovery tank 16, where the compressed condensed refrigerant has been recovered. Mixed gas 22 is fed into gas separation unit 68 via delivery pipe 56. Gas separation unit 68 separates mixed gas 22 into multiple components.

[0061] Then, pipes 58A and 58C are connected to the gas separation device 68. Pipes 58A and 58C then send the first gas component 23 of the air conditioning refrigerant separated by the gas separation module 68A to the refrigerant recovery device 14 and the refrigerant circuit 30.

[0062] The gas separation device 68 includes a gas separation module 68A disposed in the front stage and an adsorption module 68B disposed in the rear stage.

[0063] The gas separation module 68A includes an inlet 90A, a separation membrane 92A, an outlet 94A, and an outlet 96A. The inlet 90A draws in mixed gas 22.

[0064] Separating membrane 92A separates the mixed gas 22 into a first gaseous component 23 of the air conditioning refrigerant and a second mixed gas 24 (second mixed gas) consisting of a second gaseous component 25 of the air conditioning refrigerant and a non-condensable gas 26. When the mixed gas containing a large amount of non-condensable gas flows towards separating membrane 92A, the non-condensable gas 26 flows not only towards outlet 94A but also towards outlet 96A. During repeated separation processes, the amount of non-condensable gas 26 flowing towards outlet 94A increases, while the amount flowing towards outlet 96A decreases.

[0065] Outlet 94A discharges the mixed gas 24 that has passed through separator 92A into piping 59. Outlet 96A discharges the first gaseous component 23 of the air conditioning refrigerant that has not passed through separator 92A.

[0066] The first end of the sending pipe 56 is the gas inlet 60. The second end of the sending pipe 56 is connected to the inlet 90A of the gas separation module 68A.

[0067] The first end of the refeed pipe 58A is connected to the outlet 96A of the gas separation module 68A. The second end of the refeed pipe 58A is connected to the first end of the refeed pipe 58C. The second end of the refeed pipe 58C is connected to the third port 43 of the three-way valve 40 as the gas outlet 74. In addition, as will be explained later, the second ends of the refeed pipe 58A and the second ends of the refeed pipe 58B are connected to the second end of the refeed pipe 58C, but normally, the gas is configured to flow from the refeed pipe 58A to the refeed pipe 58C instead of flowing into the refeed pipe 58B.

[0068] The adsorption module 68B includes an inlet 90B, an outlet 94B, piping 57A, 57B, a three-way valve 402, and an adsorption section 315. The inlet 90B draws in mixed gas 24.

[0069] The adsorption section 315 adsorbs the second gas component 25 of the air conditioning refrigerant in the mixed gas 24 onto the adsorbent. The outlet 94B discharges the non-condensable gas 26 that was not adsorbed by the adsorption section 315.

[0070] Three-way valve 402 includes port 1 411, port 2 412, and port 3 413. Outlet 94B is connected to port 1 411 of three-way valve 402 via piping 57A. Port 2 412 of three-way valve 402 is connected to piping 57B. Port 3 413 of three-way valve 402 is connected to piping 58B.

[0071] During the adsorption process, the control unit 330 controls the first port 411 and the second port 412 of the three-way valve 402 to be in a connected state. Here, the adsorption process refers to the process in which the mixed gas 22 is separated into a first gas component 23 and a mixed gas 24 by the gas separation device 68, while the second gas component 25 of the air conditioning refrigerant is adsorbed into the adsorbent 350 in the adsorption module 68B. In this case, the non-condensable gas 26 discharged from the outlet 94B is discharged to the atmosphere via pipes 57A and 57B. Since the third port 413 of the three-way valve 402 is in a closed state, the gas does not flow to the resupply pipe 58B.

[0072] On the other hand, during the desorption process, the control unit 330 controls the first port 411 and the third port 413 of the three-way valve 402 to be in a connected state. Here, the desorption process refers to the process of desorbing and recovering the second gas component 25 of the air conditioning refrigerant adsorbed in the adsorbent 350 in the adsorption module 68B. In this case, the gas flowing in the piping 57A (the desorbed second gas component 25) flows to the refrigerant recovery device 14 via the resupply piping 58B and 58C.

[0073] Hereinafter, the process that is different from the adsorption process and the desorption process, namely the process of recovering the air conditioning refrigerant from the refrigerant circuit 30 of the air conditioning unit 12 and recovering it to the recovery storage tank 16, will be referred to as the "recovery process".

[0074] One end of pipe 59 is connected to the outlet 94A of gas separation module 68A. The second end of pipe 59 is connected to the inlet 90B of adsorption module 68B. Separation device 18 also includes a first pressure regulator 98A and a first check valve 99A.

[0075] The first pressure regulator 98A adjusts the differential pressure between the inside and outside of the separation membrane 92A of the gas separation module 68A. The first pressure regulator 98A is located after the gas separation module 68A and includes a first back pressure valve that adjusts the pressure on the primary side of the first pressure regulator 98A.

[0076] The first check valve 99A is positioned between the first pressure regulator 98A and the gas outlet 74. The first check valve 99A prevents gas flowing out of the separation membrane 92A from flowing back into the separation membrane 92A.

[0077] As explained below, detectors or valves are provided on the sending pipe 56 and the resupply pipe 58A, but some of them can be omitted to form a refrigerant recovery system. A basic refrigerant recovery method that also includes such a structure has the following steps (1) to (5).

[0078] (1) Generation step: In the recycling process, the first port 41 and the second port 42 of the three-way valve 40 are connected (hereinafter referred to as the normal mode). The air conditioning refrigerant of the refrigerant circuit 30 is guided to the refrigerant recovery device 14 through the connecting pipe 50 and the front pipe 52. The air conditioning refrigerant is compressed and condensed by the refrigerant recovery device 14 to generate compressed and condensed refrigerant.

[0079] (2) Recovery step: In the recovery process, the compressed condensed refrigerant generated by the refrigerant recovery device 14 is recovered to the recovery storage tank 16 through the post-pipeline 54.

[0080] (3) Separation step: In the adsorption process, the first port 411 and the second port 412 of the three-way valve 402 are connected, and the mixed gas 22 contained in the inside of the recovery tank 16 is guided to the gas separation device 68 through the sending pipe 56. The mixed gas 22 is separated into multiple components by the gas separation device 68 (separation device 18).

[0081] (4) Re-feeding step: In the adsorption process, the second port 42 and the third port 43 of the three-way valve 40 are connected (hereinafter referred to as the circulation mode), so that the first gas component 23 of the air conditioning refrigerant that has not passed through the separation membrane 92A is sent to the refrigerant recovery device 14 and the refrigerant circuit 30 through the re-feeding pipe 58A and the front pipe 52.

[0082] The separation step in (3) above includes the following two steps. (3A) In the first separation step, the mixed gas 22 is separated into the first gas component 23 of the air conditioning refrigerant and the mixed gas 24 (the second mixed gas) composed of the second gas component 25 of the air conditioning refrigerant and the non-condensable gas 26 through the separation membrane 92A of the gas separation module 68A.

[0083] (3B) The second separation step (also known as the "adsorption step") involves adsorbing the second gas component 25 of the air conditioning refrigerant in the mixed gas 24 (second mixed gas) separated by the separation membrane 92A of the gas separation module 68B onto the adsorption section 315 (adsorbent 350), and discharging the non-condensable gas 26 in the mixed gas 24 (second mixed gas) that is not adsorbed onto the adsorption section 315 from the outlet 94B to the atmosphere.

[0084] (5) Desorption step: In the desorption process, the first port 411 and the second port 412 of the three-way valve 402 are connected, the refrigerant recovery device 14 is activated, the second gas component 25 adsorbed on the adsorption section 315 (adsorbent 350) is desorbed, and the desorbed second gas component 25 is stored in the recovery storage tank 16.

[0085] Continue to explain Figure 1 The refrigerant recovery system 10B. The separation unit 18 also includes a pressure detector 61, a temperature detector 62, a control valve (also known as an "inlet valve") 64, and a pressure reducing valve 66, all configured on the sending piping 56.

[0086] The pressure detector 61 and temperature detector 62 on the sending piping 56 are located closer to the recovery tank 16 than the control valve 64, and detect the pressure and temperature inside the recovery tank 16.

[0087] The separation device 18 also includes a pressure detector 70 and a pressure regulator 72 configured on the refeed piping 58C.

[0088] The pressure detector 70 on the refeed piping 58C detects the pressure in the refeed piping 58C upstream of the pressure regulator 72 (towards the gas separator 68). The pressure regulator 72 adjusts the pressure in the refeed piping 58C downstream of the pressure regulator 72 (towards the gas outlet 74).

[0089] The separation device 18 also includes a sending controller 76, a refeeding controller 78, a three-way valve controller 80, and a pressure controller 97A.

[0090] The send controller 76, re-feed controller 78, three-way valve controller 80, pressure controller 97A, and control unit 330 are controllers, such as a microcomputer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), flash memory, and input / output ports. These controllers can also be implemented using a single shared microcomputer. Furthermore, these controllers can replace the microcomputer or include an ASIC (Application Specific Integrated Circuit).

[0091] In the recovery process, the sending controller 76 determines whether non-condensable gases need to be removed from the recovery storage tank 16 based on the detection value DP of the pressure detector 61 and the detection value DT of the temperature detector 62. If removal is deemed necessary, the sending controller 76 opens the control valve 64; otherwise, it closes it. When the control valve 64 is opened, the process transitions from the recovery process to the adsorption process.

[0092] When the control valve 64 is in the closed state (recovery process), the three-way valve controller 80 controls the three-way valve 40 to set the first port 41 and the second port 42 to the connected state (normal mode).

[0093] When the control valve 64 is in the open state (adsorption process), the three-way valve controller 80 controls the three-way valve 40 to connect the second port 42 and the third port 43 (circulation mode), or to connect the first port 41 and the third port 43 (hereinafter referred to as vaporization promotion mode). Thus, in... Figure 1 In the implementation method, a vaporization promotion mode is added to the basic refrigerant recovery method.

[0094] The typical mode controlled in the recovery process is the refrigerant recovery from the air conditioning unit 12 to the recovery storage tank 16. The circulation mode controlled in the adsorption process is as follows: a circulation loop is formed by the separation unit 18, the refrigerant recovery unit 14, and the recovery storage tank 16, repeatedly feeding the mixed gas 22 in the recovery storage tank 16 into the gas separation unit 68 to remove non-condensable gases from the recovery storage tank 16. This circulation mode is also controlled in the desorption process. In this case, the second gas component 25 of the adsorbent 350 adsorbed in the gas separation unit 68 is desorbed and recovered to the recovery storage tank 16.

[0095] The controlled vaporization promotion mode in the adsorption process is as follows: When the refrigerant in the refrigerant circuit 30 of the air conditioning unit 12 may condense at low temperatures, a portion of the mixed gas 22 in the recovery tank 16 is fed from the separation device 18 into the refrigerant circuit 30, causing the temperature of the refrigerant in the refrigerant circuit 30 to rise and promoting refrigerant vaporization. The gaseous refrigerant passing through the refrigerant recovery device 14 is adiabatically compressed, thus its temperature increases compared to when it flows into the refrigerant circuit 30, i.e., into the refrigerant recovery device 14. Therefore, the temperature of the refrigerant entering the recovery tank 16 from the refrigerant recovery device 14 is higher.

[0096] Pressure controller 97A controls first pressure regulator 98A to adjust the differential pressure between the inside and outside of separation membrane 92A. Furthermore, pressure controller 97A controls second pressure regulator 98B to adjust the adsorption pressure of adsorption section 315.

[0097] Figure 2 This is a block diagram of the transmitting controller 76. The transmitting controller 76 includes a reference pressure acquirer 104, a pressure reducing valve controller 106, and a decision unit 108. The separation device 18 includes an input unit 100 such as a keyboard or barcode reader and a storage unit 102 such as flash memory. The transmitting controller 76 is electrically connected to the input unit 100 and the storage unit 102. Alternatively, a memory located within the transmitting controller 76 can be used as the storage unit 102.

[0098] Before refrigerant recovery, refrigerant recovery information 110, indicating the type of refrigerant to be recovered (hereinafter also referred to as recovered refrigerant), is input from input unit 100 and stored in storage unit 102. For example, a barcode indicating the type of refrigerant used in air conditioning unit 12 is read from the surface of the frame of air conditioning unit 12 using a barcode reader that serves as input unit 100, thereby storing the refrigerant recovery information 110 in storage unit 102. In storage unit 102, the characteristics of saturated vapor pressure relative to temperature (hereinafter referred to as pressure characteristics 112) are also pre-stored for each of the various refrigerants.

[0099] Figure 3 This is a diagram showing examples of the pressure characteristics of various refrigerants. In Figure 3 The pressure characteristics of refrigerants A, B, C, and D are shown in the figure.

[0100] The reference pressure acquirer 104 inputs the detected temperature DT (temperature inside the recovery tank 16) from the temperature detector 62 on the transmission piping 56. The reference pressure acquirer 104 reads the pressure characteristic 112 corresponding to the recovered refrigerant shown in the recovered refrigerant information 110 from the storage section 102, such as... Figure 3 As shown, the recovered refrigerant (in the recovery tank 16) was obtained at the detection temperature DT (temperature inside the recovery tank 16). Figure 3 In this example, the saturated vapor pressure of refrigerant A is used as the reference pressure RP. Then, the reference pressure acquirer 104 outputs the reference pressure RP to the decision 108.

[0101] The reference pressure RP is input to the decision 108, and the detection pressure DP (pressure within the recovery tank 16) of the pressure detector 61 on the transmission piping 56 is sent. Here, as... Figure 3As shown, when the detected pressure DP is higher than the reference pressure RP (the saturated vapor pressure of the recovered refrigerant), it indicates that non-condensable gases are mixed in with the recovery tank 16. Therefore, when the detected pressure DP is higher than the reference pressure RP (hereinafter also referred to as the high-pressure state), the determiner 108 controls the control valve 64 to open, delivering the mixed gas 22 in the recovery tank 16 to the gas separation device 68. On the other hand, when the high-pressure state is not present, the determiner 108 keeps the control valve 64 closed. The determiner 108 outputs a removal signal, which indicates whether non-condensable gases have been removed. The removal signal is Low when the control valve 64 is closed and High when the control valve 64 is open.

[0102] The pressure DP (pressure within the recovery tank 16) detected by the pressure detector 61 on the transmission piping 56 is input to the pressure reducing valve controller 106. Based on the detected pressure DP, the pressure reducing valve controller 106 controls the pressure reducing valve 66 so that when the control valve 64 is open and the mixed gas 22 in the recovery tank 16 is sent to the gas separator 68, the separation membrane 92A of the gas separator 68 is not damaged by the pressure within the recovery tank 16. By controlling the pressure reducing valve 66, the pressure in the piping downstream of the pressure reducing valve 66 (towards the gas separator 68) is adjusted.

[0103] Figure 4 This is a block diagram of a three-way valve controller 80. The three-way valve controller 80 includes a decision unit 118. The three-way valve controller 80 is electrically connected to an input unit 100 such as a keyboard and a storage unit 102 such as flash memory. Alternatively, a memory located within the three-way valve controller 80 can be used as the storage unit 102.

[0104] Before refrigerant recovery, a pressure threshold 120 and a duration 122 of the vaporization promotion mode, which serve as conditions for transitioning to the vaporization promotion mode, are input from the input unit 100 and stored in the storage unit 102. A removal signal, the detection pressure DPS (pressure at the inlet 36 of the refrigerant recovery device 14) of the pressure detector 37 of the refrigerant recovery device 14, the pressure threshold 120 in the storage unit 102, and the duration 122 are input to the determination unit 118. Here, the detection pressure DPS represents the pressure of the refrigerant circuit 30 of the air conditioning unit 12 in normal mode.

[0105] When the removal signal is Low, the 118 controls the three-way valve 40 to make the first port 41 and the second port 42 of the three-way valve 40 connected (normal mode).

[0106] When the removal signal changes from Low to High, the determiner 118 decides whether to control the three-way valve 40 in either cyclic mode or vaporization-promoting mode based on a comparison between the detected pressure DPS (pressure of refrigerant circuit 30) and the pressure threshold 120. Specifically, if the detected pressure DPS is higher than the pressure threshold 120, the determiner 118 estimates that the refrigerant in refrigerant circuit 30 is unlikely to condense at low temperature, and controls the three-way valve 40 so that its second port 42 and third port 43 are connected (cyclic mode). On the other hand, if the detected pressure DPS is lower than the pressure threshold 120, the determiner 118 estimates that the refrigerant in refrigerant circuit 30 may condense at low temperature, and controls the three-way valve 40 so that its first port 41 and third port 43 are connected (vaporization-promoting mode).

[0107] When the time elapsed from the transition to the vaporization promotion mode is 122, the detector 118 controls the three-way valve 40 to switch from the vaporization promotion mode to the circulation mode.

[0108] The output of the determiner 118 is a three-way valve signal indicating whether the current state is normal mode, cycle mode or vaporization promotion mode.

[0109] like Figure 1 As shown, the recharge controller 78 receives a three-way valve signal, the pressure DPR (pressure within the recharge pipe 58) detected by the pressure detector 70 on the recharge pipe 58C, and the pressure DPS (pressure at the inlet 36 of the refrigerant recovery device 14) detected by the pressure detector 37. When the three-way valve signal indicates a circulation mode, the recharge controller 78 controls the pressure regulator 72 based on the detected pressures DPR and DPS, ensuring that the pressure within the recharge pipe 58C downstream of the pressure regulator 72 (towards the gas outlet 74) is higher than the pressure at the inlet 36 of the refrigerant recovery device 14. This prevents refrigerant from flowing back from the front pipe 52 towards the recharge pipe 58C. When the three-way valve signal indicates a vaporization promotion mode, the recharge controller 78 controls the pressure regulator 72, ensuring that the pressure within the recharge pipe 58C downstream of the pressure regulator 72 (towards the gas outlet 74) reaches a predetermined pressure sufficient to supply gas into the refrigerant circuit 30 of the air conditioning unit 12.

[0110] Figure 5 This is a block diagram of a pressure controller 97A. The pressure controller 97A includes a pressure acquisition unit 211A, a first pressure controller 212, and a second pressure controller 213. The pressure controller 97A is electrically connected to a storage unit 102, such as flash memory. Alternatively, a memory located within the pressure controller 97A can be used as the storage unit 102.

[0111] Storage unit 102A stores first pressure information 214 and second pressure information 215. First pressure information 214 represents the differential pressure PA between the inside and outside of the separation membrane 92A, set by the first pressure regulator 98A. Second pressure information 215 represents the adsorption pressure PB of the adsorption unit 315, set by the second pressure regulator 98B.

[0112] The second pressure regulator 98B adjusts the adsorption pressure of the adsorption section 315 of the adsorption module 68B during adsorption. The second pressure regulator 98B is disposed after the adsorption module 68B and includes a second back pressure valve for adjusting the pressure on the primary side of the second pressure regulator 98B.

[0113] Before refrigerant recovery, pressure acquisition device 211A obtains first pressure information 214 from storage unit 102A and sends it to first pressure controller 212. First pressure controller 212 controls first pressure regulator 98A to set the differential pressure P1o between the inside and outside of separator 92A to PA.

[0114] Before refrigerant recovery, pressure acquisition device 211A obtains second pressure information 215 from storage unit 102A and sends it to second pressure controller 213. Second pressure controller 213 controls second pressure regulator 98B to set the adsorption pressure of adsorption unit 315 to PB.

[0115] If the adsorption pressure PB of the adsorption section 315 is high, the refrigerant is more easily adsorbed onto the adsorbent 350, and the amount of refrigerant adsorbed per unit weight of adsorbent 350 increases. Therefore, the amount of adsorbent 350 used can be reduced.

[0116] Therefore, when the adsorption pressure PB of the adsorption unit 315 is above the reference value, the control unit 330 can switch the outflow destination of the switching valve 320 to the first adsorption unit 321 filled with a small amount of adsorbent 350, and when the adsorption pressure PB of the adsorption unit 315 is less than the reference value, the control unit 330 can switch the outflow destination of the switching valve 320 to the second adsorption unit 322 filled with a large amount of adsorbent 350.

[0117] Next, the setting pressure PA of the internal and external differential pressure of the separation membrane 92A will be explained. Figure 6 This is a diagram used to illustrate the set pressure PA of the internal and external differential pressure of the separation membrane 92A.

[0118] When a mixed gas containing a non-condensable gas 26 at a flow rate exceeding that of the separator flows to the separator 92A, the non-condensable gas 26 may flow not only to the outlet 94A but also to the outlet 96A. To prevent this, the inflow rate of the mixed gas 22 to the separator 92A needs to be adjusted.

[0119] Even when a large amount of non-condensable gas 26 flows towards the separation membrane 92A, the non-condensable gas 26 is returned to the recovery storage tank 16 through the outlet 96A and the refrigerant recovery unit 14. Then, the non-condensable gas 26 flows back into the separation unit 18 and undergoes the separation process. The repeated flow of non-condensable gas 26 into the separation unit 18 reduces the amount of non-condensable gas 26.

[0120] The set pressure PA of the differential pressure between the inside and outside of the separator 92A is set to be less than the first threshold TH1. As a result, the second gas component 25 and the non-condensable gas 26 of the air conditioning refrigerant can easily pass through the separator 92A, while the first gas component 23 of the air conditioning refrigerant cannot easily pass through the separator 92A.

[0121] Regarding the setting of pressure PA, a method for setting a more appropriate value that meets the above conditions will be explained.

[0122] like Figure 1 As shown, the differential pressure between the inside and outside of the separation membrane 92A is set to P1o, the internal pressure of the separation membrane 92A (i.e., the pressure on the input side of the separation membrane 92A) is set to P1i, and the pressure on the permeation side of the separation membrane 92A is set to P1t. When the pressure on the input side of the adsorption module 68B is set to P2i, the following formula holds true.

[0123] P1t=P2i …(1)

[0124] P1t=P1i-P1o …(2)

[0125] To prevent gas from flowing back into the separation membrane 92A, the following conditions are required.

[0126] P1i>P1t=P2i …(3)

[0127] By sending the controller 76 to control the pressure reducing valve 66, the pressure P1i can be controlled in a manner that satisfies equation (3).

[0128] The pressure controller 97A controls the internal and external differential pressure P1o of the separation membrane 92A of the gas separation module 68A by controlling the first pressure regulator 98A, so that equation (4) is satisfied.

[0129] P1o=PA <TH1 …(4)

[0130] Next, the gas separation module 68A will be described. Mixed gas 22 flows into the gas separation module 68A.

[0131] like Figure 1As shown, the gas separation module 68A includes a cylindrical frame 88A and a cylindrical separation membrane 92A disposed within the frame 88A. The frame 88A includes: an inlet 90A for taking in mixed gas 22; an outlet 96A opposite to the inlet 90A for discharging the first gaseous component 23 of the air conditioning refrigerant (re-feeding gaseous refrigerant); and an outlet 94A for discharging a mixed gas 24 consisting of non-condensable gas 26 and the second gaseous component 25 of the air conditioning refrigerant (referred to as "R-32" in this embodiment).

[0132] Approximately half of the second gaseous component 25 (R-32) of the air conditioning refrigerant permeates through the separation membrane 92A. Non-condensable gas 26 easily permeates through the separation membrane 92A. Here, the first gaseous component 23 can be an air conditioning refrigerant other than R-32, which is difficult to permeate through the separation membrane 92A; it can also be R-32 that does not permeate through the separation membrane 92A; or it can be a mixture of R-32 that does not permeate through the separation membrane 92A and an air conditioning refrigerant other than R-32, which is difficult to permeate through the separation membrane 92A.

[0133] The first end of the separator 92A is connected to the inlet 90A of the frame 88A. The second end of the separator 92A is connected to the outlet 96A of the frame 88A. The mixed gas 22 enters the interior of the separator 92A from the inlet 90A and moves toward the outlet 96A. During this process, approximately half of the non-condensable gas 26 and the second gaseous component 25 (R-32) of the air conditioning refrigerant permeates through the separator 92A and is discharged outside the separator 92A, eventually exiting through the outlet 94A of the frame 88A into the piping 59. In addition, the first gaseous component 23 of the air conditioning refrigerant in the mixed gas 22 that did not permeate through the separator 92A (the remaining R-32 and other air conditioning refrigerant) is discharged from the outlet 96A of the frame 88A into the recharge piping 58A.

[0134] As the separation membrane 92A, for example, a membrane made of inorganic materials (hereinafter referred to as an inorganic separation membrane) or a membrane made of organic materials (hereinafter referred to as an organic separation membrane) can be used. For example, ceramics, zeolites, etc., can be used as materials for inorganic separation membranes. Separation membrane 92A is a membrane capable of separating non-condensable gases (N2, O2) and other gases with small separation diameters. The molecular diameter of separation membrane 92A is approximately 3.8 Å. Separation membrane 92A is polar.

[0135] Figure 7 This is a schematic diagram illustrating the principle of a molecular sieve, 92A, composed of an inorganic separation membrane. (See diagram for example.) Figure 7As shown, the inorganic molecular membrane has fine pores (micropores) and basically utilizes the principle of molecular sieves for gas separation. Compared to the micropore size of the inorganic molecular membrane, air (non-condensable gas 26), water 28, and R-32 (second gas component 25) from the refrigerant, which have small molecular diameters, pass through the micropores and flow out of the separation membrane. The molecular diameter of R-32 is close to that of the inorganic separation membrane; therefore, its permeation rate is smaller compared to air (non-condensable gas 26).

[0136] Next, the adsorption module 68B will be described. The mixed gas 24 (second mixed gas) that has passed through the separation membrane 92A flows into the adsorption module 68B.

[0137] The adsorption unit 315 includes a switching valve 320, a first adsorption unit 321, a second adsorption unit 322 arranged in parallel with the first adsorption unit 321, a third adsorption unit 323 arranged after the first adsorption unit 321 and the second adsorption unit 322, and a refrigerant detection sensor 324.

[0138] The switching valve 320 switches whether the mixed gas 24 is delivered to the first adsorption unit 321 or the second adsorption unit 322. The switching valve 320 is controlled by the control unit 330.

[0139] A large amount of adsorbent is packed into the first adsorption unit 321, the second adsorption unit 322, and the third adsorption unit 323. The larger the surface area of ​​the adsorbent, the higher its adsorption performance. Small adsorbent particles may flow into the piping. Therefore, the particle size of the adsorbent is preferably about 0.1 to 10 mm. Examples of adsorbents that can be used include zeolite, activated carbon, silica alumina, activated alumina, and synthetic zeolite.

[0140] In this embodiment, zeolite with a pore size of approximately 3 to 10 Å is used as the adsorbent. For example, cylindrical type A zeolite with a pore size of 9 Å and a height of 1.5 mm is packed as the adsorbent in each adsorption unit 321, 322, and 323. Such zeolite can not only adsorb R-32, but also desorb R-32 adsorbed on the zeolite.

[0141] Figure 8 This is a diagram showing the details of the first adsorption unit 321, the second adsorption unit 322, and the third adsorption unit 323.

[0142] Adsorbent 350 is filled in each adsorption unit 321, 322, and 323. The second gaseous component 25 (R-32) of the air conditioning refrigerant can be adsorbed into the adsorbent 350. Moreover, the second gaseous component 25 (R-32) adsorbed into the adsorbent 350 can be desorbed from the adsorbent 350.

[0143] Figure 9This diagram illustrates an example of refrigerant being adsorbed by adsorbent 350. Assuming the diameter of the pores in adsorbent 350 is approximately equal to the diameter of the second gaseous component 25 of the air conditioning refrigerant, the second gaseous component 25 of the air conditioning refrigerant is easily adsorbed into the pores of adsorbent 350. In this case, once adsorbed, the second gaseous component 25 is difficult to detach from the pores, thus desorption is difficult.

[0144] On the other hand, the diameter of the second gas component 25 (R-32) in this embodiment is slightly smaller than the diameter of the pores of the adsorbent 350, so it is easy to be adsorbed into the pores of the adsorbent 350. In addition, the second gas component 25 (R-32) adsorbed into the pores of the adsorbent 350 begins to desorb when the pressure in each adsorption unit 321, 322, 323 is reduced.

[0145] The diameter of non-condensable gas 26 is smaller than that of the second gas component 25. Therefore, non-condensable gas 26 is not adsorbed by adsorbent 350. Since the diameter of gas component 29 is larger than the diameter of the pores of adsorbent 350, gas component 29 is not adsorbed by adsorbent 350.

[0146] Figure 10 This diagram illustrates another example of refrigerant being adsorbed by adsorbent 350. Small pores and cracks also exist within the large particles of adsorbent 350. The second gaseous component 25 of the air conditioning refrigerant readily adsorbs into such pores and cracks.

[0147] When zeolite is used as adsorbent 350, it can adsorb and desorb R-32. Zeolite can also adsorb and desorb air conditioning refrigerants other than R-32. However, non-condensable gas 26 is not adsorbed by adsorbent 350. For example, when the air conditioning refrigerant is R-32, R-32 is more easily desorbed when using zeolite as adsorbent 350 compared to activated carbon and the like. Therefore, it can be said that zeolite is suitable for the adsorption and desorption of R-32.

[0148] return Figure 1 The second adsorption unit 322 contains more adsorbent than the first adsorption unit 321, and the second adsorption unit 322 can adsorb more refrigerant than the first adsorption unit 321.

[0149] The first threshold pressure TP is input to the control unit 330 and the detection pressure DP (pressure inside the recovery tank 16) of the pressure detector 61 on the piping 56 is sent.

[0150] When the detection pressure DP is below the first threshold pressure TP, the control unit 330 sets the adsorption unit 315 to be used in the first adsorption unit 321 and the second adsorption unit 322 as the first adsorption unit 321. This is because if the amount of non-condensable gas 26 mixed in the refrigerant gas is small, the volume of mixed gas 22 in the recovery tank 16 becomes smaller, and the detection pressure DP also becomes smaller, so it is conceivable that the amount of the second gas component 25 of the air conditioning refrigerant adsorbed will also be small. The control unit 330 switches the outflow destination of the switching valve 320 to the direction of the first adsorption unit 321.

[0151] When the detection pressure DP exceeds the first threshold pressure TP, the control unit 330 sets the adsorption unit 315 to be used as the second adsorption unit 322, instead of the first adsorption unit 321. This is because if the amount of non-condensable gas 26 mixed in the refrigerant gas is large, the volume of the mixed gas 22 in the recovery tank 16 will increase, and the detection pressure DP will also increase, so it is conceivable that the amount of the second gas component 25 of the air conditioning refrigerant adsorbed will also be large. The control unit 330 switches the outflow destination of the switching valve 320 to the direction of the second adsorption unit 322.

[0152] The mixed gas 24 flows into the adsorption section 315 used in the first adsorption unit 321 and the second adsorption unit 322. Most of the second gas component 25 of the air conditioning refrigerant contained in the mixed gas 24 is adsorbed by the adsorbent in the adsorption section 315, and most of the non-condensable gas 26 contained in the mixed gas 24 flows out from the adsorption section 315.

[0153] The third adsorption unit 323 is disposed after the first adsorption unit 321 and the second adsorption unit 322. When the gas flowing out from the adsorption section 315 used in the first adsorption unit 321 and the second adsorption unit 322 contains the second gas component 25 of the air conditioning refrigerant, the adsorbent of the third adsorption unit 323 adsorbs them.

[0154] Non-condensable gas 26 contained in the gas flowing out of the adsorption unit 315 flows out from the third adsorption unit 323. The non-condensable gas 26 is discharged to the atmosphere from the outlet 94B via pipes 57A and 57B. In this case, the first port 411 and the second port 412 of the three-way valve 402 are controlled to be in the connected state.

[0155] The refrigerant detection sensor 324 detects whether the gas flowing out of the adsorption section 315 used in the first adsorption unit 321 and the second adsorption unit 322 contains refrigerant. The refrigerant detection sensor 324 is, for example, composed of an infrared sensor.

[0156] When the refrigerant detection sensor 324 detects refrigerant, the control unit 330 determines that the adsorption unit 315 currently in use in the first adsorption unit 321 and the second adsorption unit 322 is damaged (the adsorption unit 315 is unable to adsorb refrigerant), and switches the unused adsorption unit 315 to the adsorption unit 315 in use. The control unit 330 then switches the outflow destination of the switching valve 320 to the direction of the newly used adsorption unit 315.

[0157] As described above, in this embodiment, R-32 (second gas component 25) can be adsorbed and desorbed relative to the adsorbent 350. When only R-32 is adsorbed onto the adsorbent 350, or when an adsorbent 350 that cannot desorb R-32 is used, the adsorbent 350 needs to be discarded after a certain amount of R-32 has been adsorbed.

[0158] The adsorbent 350 in this embodiment can desorb the adsorbed R-32, thus allowing the adsorbent 350 to be reused. This reduces the cost of the adsorbent.

[0159] Furthermore, in this embodiment, the gas separation module 68A first separates the mixed gas 22 into a first gaseous component 23 of the air conditioning refrigerant and a mixed gas 24 (second mixed gas) consisting of a second gaseous component 25 of the air conditioning refrigerant and a non-condensable gas 26. Next, the adsorption module 68B adsorbs the second gaseous component 25 onto the adsorbent 350 and discharges the non-condensable gas 26 into the atmosphere.

[0160] For example, when the mixed gas 22 consists of R-32 and non-condensable gas 26, approximately half of the R-32 is separated by the gas separation module 68A and discharged from the outlet 96A as the first gas component 23 of the air conditioning refrigerant. Afterwards, the mixed gas 24, containing the remaining half of the R-32 and non-condensable gas 26, is sent to the adsorption module 68B, where the remaining R-32 is adsorbed by the adsorbent 350 of the adsorption module 68B.

[0161] The gas separation device 68 can also consist solely of the adsorption module 68B. In this case, the gas separation module 68A is omitted, thereby reducing the device cost. On the other hand, when the gas separation device 68 is composed of the gas separation module 68A and the adsorption module 68B, approximately half of the R-32 can be separated by the gas separation module 68A, therefore the amount of adsorbent 350 required by the adsorption module 68B is also only half. In this case, there are advantages such as miniaturization of the adsorption module 68B and reduction of the cost of the adsorbent 350.

[0162] In this embodiment, when the mixed gas 22 consists of R-32, other air conditioning refrigerants, and non-condensable gases 26, approximately half of the R-32 and all of the other air conditioning refrigerants are separated by the gas separation module 68A and discharged as the first gaseous component 23 of the air conditioning refrigerant from the outlet 96A. Furthermore, in the adsorption module 68B, only R-32 is adsorbed and desorbed. Without utilizing the gas separation module 68A, R-32 and other air conditioning refrigerants are adsorbed and desorbed in the adsorption module 68B.

[0163] Figure 11 This is a graph showing the relationship between vacuum level and the adsorption rate of R-32 on zeolite. R-32 (second gas component 25) is physically adsorbed onto zeolite (adsorbent 350). The adsorption energy of physical adsorption onto adsorbent 350 is lower than that of chemical adsorption onto adsorbent 350. Therefore, in the case of physical adsorption onto adsorbent 350, desorption is easier compared to chemical adsorption onto adsorbent 350. Furthermore, in the case of physical adsorption, the adsorption amount increases linearly with increasing pressure (Henry's Law).

[0164] Specific examples are shown. For example... Figure 11 As shown, when the pressure inside the adsorption unit is P2 (0 MPa), the adsorption rate (= adsorption amount / saturated adsorption amount) relative to adsorbent 350 (zeolite) is 70%. In this case, if the pressure inside the adsorption unit is reduced, the adsorption rate decreases linearly, and when the pressure inside the adsorption unit is P1, the adsorption rate of adsorbent 350 (zeolite) becomes 20%.

[0165] If Figure 11 The relationship between vacuum degree and the adsorption rate of R-32 on zeolite shown can be rewritten as the relationship between vacuum degree and the desorption rate of R-32 on zeolite (= desorption amount / saturated adsorption amount). Then, as follows... Figure 12 As shown. Figure 12 This is a graph showing the relationship between vacuum level and the desorption rate of R-32 on zeolite.

[0166] At a pressure of P2 (0 MPa) within the adsorption unit, the desorption rate is 30% (=100%-70%). When the pressure within the adsorption unit is reduced to P1, the desorption rate reaches 80% (=100%-20%). For example, as shown in this graph, to ensure a desorption rate of over 60%, the desorption pressure needs to be below -0.06 MPa.

[0167] In this embodiment, in the above-described adsorption process (circulation mode, vaporization promotion mode), the second gaseous component 25 (R-32) of the air conditioning refrigerant is adsorbed onto the adsorbent 350 in the adsorption unit 315 (first adsorption unit 321, second adsorption unit 322, or third adsorption unit 323). Then, in the desorption process performed after the adsorption process, the second gaseous component 25 (R-32) of the air conditioning refrigerant adsorbed onto the adsorbent 350 is desorbed.

[0168] During the desorption process, the control unit 330 closes the control valve 64. Furthermore, similar to the circulation mode, the control unit 330 controls the second port 42 and the third port 43 of the three-way valve 40 to be in a connected state. Moreover, the control unit 330 controls the first port 411 and the third port 413 of the three-way valve 402 to be in a connected state.

[0169] In this state, the refrigerant recovery device 14 is activated. In this state, the control valve 64 is closed, the second port 42 and the third port 43 of the three-way valve 40 are connected, and the first port 411 and the third port 413 of the three-way valve 402 are connected. As a result, the gas in the adsorption section 315 is drawn by the suction pump of the refrigerant recovery device 14, and the pressure in each adsorption unit decreases.

[0170] The result is that, if used Figure 12 As explained, the second gaseous component 25 (R-32) of the air conditioning refrigerant adsorbed in the adsorbent 350 of each adsorption unit begins to desorb. Furthermore, the desorbed second gaseous component 25 of the air conditioning refrigerant is drawn in by the suction pump of the refrigerant recovery device 14 via pipes 57A, 58B, 58C, and 52, and is recovered into the recovery storage tank 16 as a compressed condensed refrigerant that has been compressed and condensed by the refrigerant recovery device 14.

[0171] Thus, by performing a desorption process after the adsorption process, the second gaseous component 25 of the air conditioning refrigerant adsorbed on the adsorbent 350 is desorbed. Therefore, by repeatedly performing the adsorption and desorption processes, the adsorbent 350 can be reused repeatedly.

[0172] Figure 13 This is a graph showing the shift in the outlet concentration of R-32 in the adsorption and desorption processes. The vertical axis represents the concentration (outlet concentration) of the second gas component 25 (R-32) of the air conditioning refrigerant in the outlet 94B of the adsorption module 68B, and the horizontal axis represents time.

[0173] During the adsorption process, the second gaseous component 25 (R-32) of the air conditioning refrigerant is completely adsorbed by the adsorbent 350, resulting in an outlet concentration of 0 ppm for R-32. Subsequently, when switching to the desorption process, the refrigerant recovery unit 14 draws the refrigerant into a near-vacuum state within each adsorption unit, causing the R-32 desorbed from the adsorbent 350 to flow out from the outlet 94B of the adsorption module 68B. At this point, the outlet concentration of R-32 is at its maximum (e.g., approximately 27,000 ppm).

[0174] Subsequently, the amount of R-32 adsorbed on adsorbent 350 decreased, and the concentration of R-32 flowing out of outlet 94B decreased, eventually reaching 0 ppm at the outlet, at which point the desorption process ended. Subsequently, with repeated adsorption and desorption processes, the outlet concentration of R-32 exhibited the same variation.

[0175] Next, the specific refrigerant recovery method using the refrigerant recovery system 10B will be explained. Figure 14 , Figure 15 This is a flowchart illustrating a specific refrigerant recovery method using the refrigerant recovery system 10B in Embodiment 1. Figure 14 , Figure 15 In this process, steps S100-S103, S126, and S127 are steps performed by the operator, while the other steps are performed automatically by the refrigerant recovery system 10B.

[0176] In S100, the operator prepares the refrigerant recovery device 14, the recovery storage tank 16, and the separation device 18. Here, in the refrigerant recovery system 10B, the refrigerant recovery device 14 and the recovery storage tank 16 function as the desorption device 19 in the desorption process.

[0177] In S101, after the operator disconnects the power supply to the air conditioning unit 12, as follows: Figure 1 As shown, the air conditioning unit 12, the refrigerant recovery unit 14, the recovery storage tank 16, and the separation unit 18 are interconnected.

[0178] In step S102, the operator connects the power supply to the separation unit 18. Afterwards, the operator inputs the refrigerant recovery information 110 from the input unit 100 (see reference). Figure 2 ), pressure threshold 120 and duration 122 associated with gasification promotion mode (refer to Figure 4 When the power supply to the separation device 18 is turned on, the three-way valve controller 80 controls the three-way valve 40 to the normal mode in which the first port 41 and the second port 42 are connected.

[0179] In step S103, the operator activates the refrigerant recovery device 14. This initiates the recovery of refrigerant from the air conditioning unit 12.

[0180] S104~S125 are the automatic controls of the refrigerant recovery system 10B. In S104, at the start of the recovery process, the reference pressure acquirer 104 of the sending controller 76 is based on the pressure characteristics of the recovered refrigerant shown in the recovered refrigerant information 110 (reference). Figure 3 The saturated vapor pressure of the recovered refrigerant at the detection temperature DT (temperature inside the recovery tank 16) of the temperature detector 62 is used as the reference pressure RP. The decision unit 108 of the sending controller 76 confirms whether the detection pressure DP (pressure inside the recovery tank) of the pressure detector 61 is higher than the reference pressure RP. In addition, as shown in S104, the decision unit 108 can also confirm whether the detection pressure DP (pressure inside the recovery tank) is higher than the pressure obtained by adding a predetermined pressure A to the reference pressure RP (RP+α, hereinafter referred to as the reference pressure).

[0181] If the detection pressure DP is below the reference pressure (RP+α) (S104: No), the arbitrator 108 determines that it is not necessary to remove the non-condensable gas in the recovery tank 16 and continues the refrigerant recovery (S105).

[0182] On the other hand, when the detection pressure DP is higher than the reference pressure (RP+α) (S104: Yes), the determiner 108 determines that non-condensable gas needs to be removed from the recovery tank 16, changes the removal signal from Low to High, and proceeds to S106. Furthermore, if the reference pressure is used for determination in this way, the removal of non-condensable gas can begin after a certain level of non-condensable gas has accumulated in the recovery tank 16.

[0183] In S106, at the start of the adsorption process, the three-way valve controller 80 receives a removal signal that changes from Low to High and executes the first three-way valve control. Figure 16 This is a flowchart showing the control of the first three-way valve.

[0184] In S200, the determiner 118 of the three-way valve controller 80 confirms whether the detection pressure DPS (pressure of the refrigerant circuit 30) of the pressure detector 37 of the refrigerant recovery device 14 is below the pressure threshold 120 in the storage section 102. In addition, the pressure threshold 120 is, for example, about 0.1 MPa.

[0185] If the condition is not met in S200, the determiner 118 estimates that the refrigerant in the refrigerant circuit 30 of the air conditioning unit 12 is unlikely to condense at low temperature, controls the three-way valve 40 to a circulation mode that connects the second port 42 and the third port 43 (S206), sets the vaporization promotion flag to invalid (S208), and ends the control of the first three-way valve.

[0186] On the other hand, if S200 is true, the determiner 118 estimates that the refrigerant in the refrigerant circuit 30 of the air conditioning unit 12 is likely to condense at low temperature, controls the three-way valve 40 to the vaporization promotion mode that connects the first port 41 and the third port 43 (S202), sets the vaporization promotion flag to active (S204), and ends the control of the first three-way valve.

[0187] Refer again Figure 14 When the detection pressure DP is below the first threshold pressure TP (S107: Yes), the control unit 330 sets the adsorption unit 315 to be used as the first adsorption unit 321 and switches the outflow destination of the switching valve 320 to the direction of the first adsorption unit 321.

[0188] When the detection pressure DP exceeds the first threshold pressure TP (S107: No), the control unit 330 sets the adsorption unit 315 to be used as the second adsorption unit 322 and switches the outflow destination of the switching valve 320 to the direction of the second adsorption unit 322.

[0189] In S110, the pressure controller 97A begins to adjust the internal and external differential pressure P1o of the separation membrane 92A of the gas separation module 68A toward the set pressure PA by controlling the first pressure regulator 98A.

[0190] In S111, the determiner 108 of the send controller 76 opens the control valve 64 on the send piping 56. Furthermore, the timing of changing the removal signal from Low to High, the execution timing of S106 (first three-way valve control), and the execution timing of S111 (opening the control valve 64) are approximately simultaneous. Additionally, before opening the control valve 64, the pressure reducing valve 66 is adjusted by the pressure reducing valve controller 106. By opening the control valve 64, the mixed gas 22 in the recovery storage tank 16 is sent to the gas separation unit 68.

[0191] In the circulation mode, a circulation loop is formed consisting of the separation device 18, the refrigerant recovery device 14, and the recovery storage tank 16. The mixed gas 22 in the recovery storage tank 16 is repeatedly fed into the gas separation device 68. Non-condensable gases are released to the atmosphere. The refrigerant gas is fed into the pre-pipeline 52 before the refrigerant recovery device 14, and returns to the recovery storage tank 16 in a liquefied state through the refrigerant recovery device 14. As a result, the non-condensable gases in the recovery storage tank 16 are gradually removed, and the pressure in the recovery storage tank 16 decreases.

[0192] In the vaporization-enhanced mode, the refrigerant gas, which is part of the mixed gas 22 in the recovery tank 16, is fed into the refrigerant circuit 30 of the air conditioning unit 12, causing the temperature of the refrigerant in the refrigerant circuit 30 to rise. This promotes refrigerant vaporization, thereby increasing the refrigerant recovery rate when refrigerant recovery restarts.

[0193] In both circulation mode and vaporization promotion mode, the refeed controller 78 controls the pressure regulator 72 to adjust the pressure in the refeed piping 58A downstream of the pressure regulator 72 (gas outlet 74 side).

[0194] In S112, the decision unit 108 of the sending controller 76 confirms whether the detection pressure DP (pressure inside the recovery tank 16) of the pressure detector 61 is below the reference pressure RP. If the result is no in S112, the removal of non-condensable gases continues (S113), and proceeds to S114.

[0195] When the refrigerant detection sensor 324 detects refrigerant (S114: Yes), the control unit 330 switches the outflow destination of the switching valve 320.

[0196] In S116, the three-way valve controller 80 performs the control of the second three-way valve. Figure 17 This is a flowchart showing the control of the second three-way valve.

[0197] In S300, the determiner 118 of the three-way valve controller 80 confirms whether the vaporization promotion flag is valid. If S300 is not valid (in the case of cycle mode), the control of the second three-way valve ends. On the other hand, if S300 is valid (in the case of vaporization promotion mode), the process proceeds to S302.

[0198] S302 In this process, the determiner 118 confirms whether the duration 122 in the storage unit 102 has elapsed since the transition to the gasification promotion mode (see reference). Figure 4 The time is specified. If S302 is not specified, the determiner 118 determines that the vaporization promotion mode needs to be maintained and ends the control of the second three-way valve. On the other hand, if S302 is specified, the determiner 118 determines that the vaporization promotion mode can be ended, controls the three-way valve 40 in a loop mode connecting the second port 42 and the third port 43 (S304), sets the vaporization promotion flag to invalid (S306), and ends the control of the second three-way valve.

[0199] Refer again Figure 14 In S112, if the detection pressure DP (pressure inside the recovery tank 16) of the pressure detector 61 is below the reference pressure RP (S112: Yes), the decision 108 of the sending controller 76 determines that the removal of non-condensable gas in the recovery tank 16 is complete, and proceeds to S117.

[0200] In S117, the determiner 108 of the sending controller 76 closes the control valve 64 on the sending piping 56, changing the removal signal from High to Low. The determiner 118 of the three-way valve controller 80, receiving the change from High to Low, controls the three-way valve 40 in its normal mode, connecting port 1 41 and port 2 42. The pressure reducing valve controller 106 of the sending controller 76 terminates the control of the pressure reducing valve 66 and then sends a signal to the controller 78 to terminate the control of the pressure regulator 72.

[0201] In S118, the pressure controller 97 ends by adjusting the internal and external differential pressure P1o of the separation membrane 92A of the gas separation module 68A to the set pressure PA by controlling the first pressure regulator 98A.

[0202] exist Figure 15 In step S119, the refrigerant recovery device 14 checks whether the detection pressure DPS (pressure of the refrigerant circuit 30) of the pressure detector 37 has become negative. If S119 is negative, the refrigerant recovery device 14 continues refrigerant recovery (S120). If S119 is positive, the refrigerant recovery device 14 communicates to the operator that refrigerant recovery has ended via a light or sound.

[0203] The desorption process begins in S121. In S121, the control unit 330 estimates the amount of the second gaseous component 25 (R-32) of the air conditioning refrigerant adsorbed by the adsorbent 350 in the adsorption unit 315 in the adsorption process, and calculates the pressure in the adsorption unit controlled in the desorption process and the time required for the desorption process (referred to as "the specified time") based on the estimated amount of adsorption.

[0204] In S122, the control unit 330 closes the control valve 64, causing the three-way valves 40 and 402 to switch to desucking mode. Specifically, the control unit 330 controls the second port 42 and the third port 43 of the three-way valve 40 to be in a connected state, and controls the first port 411 and the third port 413 of the three-way valve 402 to be in a connected state.

[0205] In S123, the control unit 330 drives the suction pump of the refrigerant recovery device 14. As a result, the second gaseous component 25 (R-32) of the desorbed air conditioning refrigerant is recovered into the recovery storage tank 16. The control unit 330 continues desorption until a predetermined time (the time calculated in S121) has elapsed (S124: Yes) (S125).

[0206] When the desorption process is completed, in S126, the operator stops the refrigerant recovery unit 14. In S127, the operator disconnects the power supply to the separation unit 18.

[0207] Next, the effects of the refrigerant recovery system 10B described above will be explained. The refrigerant recovery system 10B is a system that recovers refrigerant for air conditioning from the refrigerant circuit 30 of the air conditioning unit 12, which is a refrigeration and air conditioning device. The refrigerant recovery system 10B includes a recovery tank 16 as a first recovery device, a separation device (adsorption device) 18, and a desorption device 19. The recovery tank 16 recovers compressed condensed refrigerant generated by compressing and condensing the air conditioning refrigerant. The separation device 18 includes an adsorption module 68B. The adsorption module 68B has an adsorbent 350 that adsorbs the gaseous components of the air conditioning refrigerant (the second gaseous component 25 of the air conditioning refrigerant) in the mixed gas 22 contained inside the recovery tank 16, which has recovered the compressed condensed refrigerant. This mixed gas 22 consists of the gaseous components of the air conditioning refrigerant (the first gaseous component 23 and the second gaseous component 25 of the air conditioning refrigerant) and non-condensable gases 26. The desorption device 19 desorbs the gaseous component of the air conditioning refrigerant (the second gaseous component 25 of the air conditioning refrigerant) adsorbed on the adsorbent 350 and accumulates the desorbed gaseous component of the air conditioning refrigerant (the second gaseous component 25 of the air conditioning refrigerant).

[0208] In this way, by activating the adsorption device 18, the mixed gas 22 containing non-condensable gas 26 inside the recovery tank 16 can be removed, and the second gaseous component 25 of the air conditioning refrigerant in the mixed gas 22 can be adsorbed onto the adsorbent 350. By activating the desorption device 19, the second gaseous component 25 of the air conditioning refrigerant can be desorbed from the adsorbent 350 and recovered, thus allowing the adsorbent 350 to be reused repeatedly. As a result, the amount of non-condensable gas 26 in the recovery tank 16 can be reduced, and the gas contained in the recovery tank 16 can be appropriately separated into non-condensable gas 26 and the gaseous component of the air conditioning refrigerant.

[0209] The adsorption module 68B includes an outlet 94B for discharging non-condensable gas 26 from the mixed gas 24 that has not been adsorbed by the adsorbent 350 into the atmosphere. Thus, it is possible to discharge only the non-condensable gas 26 stored in the recovery tank 16 into the atmosphere without mixing in gaseous components of the air conditioning refrigerant.

[0210] The separation device 18 further includes a gas separation module 68A. The gas separation module 68A includes a separation membrane 92A that separates the mixed gas 22 into a first gaseous component 23 of the air conditioning refrigerant and a mixed gas 24 (second mixed gas) consisting of a second gaseous component 25 of the air conditioning refrigerant and a non-condensable gas 26. The adsorbent 350 of the adsorption module 68B adsorbs the second gaseous component 25 of the air conditioning refrigerant from the mixed gas 24 (second mixed gas) separated by the gas separation module 68A. The desorption device 19 includes a refrigerant recovery device 14 and a recovery storage tank 16. The refrigerant recovery device 14 generates compressed condensed refrigerant by compressing and condensing the air conditioning refrigerant. The recovery storage tank 16 recovers the compressed condensed refrigerant generated by the refrigerant recovery device 14. The refrigerant recovery system 10B includes a refrigerant pipe 58A as a first refrigerant pipe, a refrigerant pipe 58B as a second refrigerant pipe, and a refrigerant pipe 58C as a third refrigerant pipe. A feed line 58A supplies the first gaseous component 23 of the refrigerant for air conditioning separated by the gas separation module 68A. A feed line 58B supplies the second gaseous component 25 of the refrigerant for air conditioning desorbed from the adsorbent 350. A feed line 58C mixes the first gaseous component 23 and the second gaseous component 25 and then supplies them between the refrigerant circuit 30 and the refrigerant recovery device 14.

[0211] In this way, before the adsorbent 350 of the adsorption module 68B adsorbs the gaseous components of the air conditioning refrigerant, a portion of the gaseous components of the air conditioning refrigerant can be removed by the gas separation module 68A. Therefore, the amount of adsorbent 350 required is relatively small, and the adsorption module 68B can be miniaturized. Furthermore, the gaseous components of the air conditioning refrigerant desorbed from the adsorbent 350 are compressed and condensed by the refrigerant recovery device 14, and after liquefaction, are recovered to the recovery storage tank 16. Therefore, the volume of the recovery storage tank 16 can be small, and multiple recovery storage tanks are not required.

[0212] Adsorbent 350 is a zeolite adsorbent. By using a zeolite adsorbent as adsorbent 350, the second gaseous component 25 of the air conditioning refrigerant can be appropriately adsorbed and desorbed.

[0213] The gaseous component of the refrigerant used in air conditioning (the second gaseous component 25 of the refrigerant used in air conditioning) is R-32. Therefore, R-32 can be appropriately adsorbed and desorbed.

[0214] The following describes other effects. According to the refrigerant recovery system 10B, the mixed gas 22 inside the recovery tank 16 is sent to the gas separation device 68, where non-condensable gases are separated from the mixed gas 22 and discharged to the atmosphere. The refrigerant gas, with reduced non-condensable gases compared to the mixed gas 22, is discharged from the gas separation device 68 and sent to the piping between the refrigerant circuit 30 of the air conditioning unit 12 and the refrigerant recovery device 14. The refrigerant gas then passes through the refrigerant recovery device 14 again and returns to the recovery tank 16 in a liquefied state.

[0215] This reduces the amount of non-condensable gas in the recovery tank 16 while maintaining the connection between the recovery tank 16, the refrigerant recovery device 14, and the air conditioning unit 12. It suppresses the rise in internal pressure of the recovery tank 16, increases the speed of refrigerant recovery to the recovery tank 16, and increases the refrigerant charge in the recovery tank 16. The refrigerant gas is liquefied (in a reduced volume state) and returned to the recovery tank 16, thus further increasing the refrigerant charge in the recovery tank 16. It is important that the mixed gas 22 in the recovery tank 16 is arranged in the order of recovery tank 16, gas separation device 68, and refrigerant recovery device 14 in order to deliver the mixed gas 22 in the recovery tank 16 to the gas separation device 68.

[0216] Furthermore, most of the refrigerant separated by the gas separator 68 is returned to the refrigerant circuit 30 and the refrigerant recovery unit 14. The separated refrigerant can be switched via a three-way valve 40 to flow either into the refrigerant circuit 30 or the refrigerant recovery unit 14. In the vaporization promotion mode, the refrigerant separated by the gas separator 68 is sent to the refrigerant circuit 30, thereby raising the temperature of the refrigerant within the circuit. This promotes refrigerant vaporization and increases the refrigerant recovery speed when refrigerant recovery restarts. In the circulation mode, the refrigerant separated by the gas separator 68 is sent to the refrigerant recovery unit 14, whereby the recovery process of the refrigerant separated by the gas separator 68 is performed again.

[0217] The gas separator 68 is installed at the top of the recovery tank 16. Therefore, liquid refrigerant, mixed water, and other liquid components remain at the bottom of the recovery tank 16, preventing the introduction of liquid refrigerant and large amounts of water into the separation membrane 92A and adsorbent 350 of the gas separator 68, thus suppressing the reduction in the gas separation effect of the separation membrane 92A and adsorbent 350. The air conditioning refrigerant is filled into the recovery tank 16 in a liquefied state after adiabatic compression by the refrigerant recovery device 14. Therefore, in the volume of the space within the recovery tank 16, only the refrigerant corresponding to the saturated vapor pressure vaporizes, and most of the refrigerant liquefies within the recovery tank 16. Because the proportion of vaporized refrigerant (gaseous refrigerant) is low, the amount of gaseous refrigerant supplied to the gas separator 68 can be reduced, and the risk of refrigerant leakage in the gas separator 68 can also be reduced.

[0218] A circulation loop is formed between the separation device 18, the refrigerant recovery device 14, and the recovery storage tank 16. Non-condensable gases are repeatedly separated by the gas separation device 68, thus effectively removing non-condensable gases from the recovery storage tank 16.

[0219] The control valve 64 is set to the open state and the gas separation device 68 is used to remove the non-condensable gas only when there is non-condensable gas mixed in the recovery tank 16. Therefore, it is possible to avoid the unnecessary use of the gas separation device 68 when there is no non-condensable gas or a small amount of non-condensable gas in the recovery tank 16.

[0220] The storage section 102 of the separation device 18 stores the pressure characteristics 112 of various refrigerants, so that a common separation device 18 can be used for the recovery of different types of refrigerants.

[0221] When using the gas separator 68 (with control valve 64 in the open state), if the pressure in the refrigerant circuit 30 is higher than a predetermined pressure, rechargeable gaseous refrigerant can be reliably fed into the refrigerant recovery unit 14 from the recharge pipe 58A. Furthermore, when using the gas separator 68 (with control valve 64 in the open state), if the pressure in the refrigerant circuit 30 is lower than a predetermined pressure, rechargeable gaseous refrigerant (with a higher temperature than that in the refrigerant circuit 30) that is part of the gaseous refrigerant in the recovery tank 16 can be fed into the refrigerant circuit 30. The recovery tank 16 contains refrigerant that has been adiabatically compressed by the refrigerant recovery unit 14 and has a higher temperature than when it flows into the refrigerant recovery unit 14. This allows the temperature of the refrigerant in the refrigerant circuit 30 to rise, promoting refrigerant vaporization and increasing the refrigerant recovery speed when refrigerant recovery restarts.

[0222] Furthermore, when the refrigerant used in air conditioning contains R-32, it is impossible to separate the non-condensable gas 26 from the refrigerant gases 23 and 25 using only one gas separation module. In this embodiment, by using two gas separation modules, only the non-condensable gas 26 can be discharged into the atmosphere.

[0223] In this embodiment, the adsorption module 68B includes an adsorption section 315 containing an adsorbent 350, which readily adsorbs the second gas component 25 of the air conditioning refrigerant. By using the adsorbent 350, the mixed gas 24 that could not be separated by the separation membrane 92A of the gas separation module 68A can be separated. Furthermore, since the adsorption module 68B does not use a separation membrane different from the separation membrane 92A of the gas separation module 68A, but uses an adsorbent, the disposal and recovery of gases that are not released into the atmosphere become easier.

[0224] In this embodiment, a first adsorption unit 321 and a second adsorption unit 322 are provided, each containing a different amount of adsorbent. By using adsorption units corresponding to the adsorption amount, only the adsorbent that has permeated through can be recovered and discarded. In particular, the adsorbent that has adsorbed R-32 is irreversible and must therefore be discarded and replaced, resulting in a significant effect.

[0225] Furthermore, according to this embodiment, even if the first adsorption unit 321 or the second adsorption unit 322, which is the main adsorption unit, fails to adsorb, the presence of the third adsorption unit 323 prevents refrigerant from remaining in the gas discharged into the atmosphere and thus preventing refrigerant from leaking into the atmosphere.

[0226] Furthermore, any or all of the adsorption units from the first adsorption unit 321 to the third adsorption unit 323 can be configured as removable units. By configuring the adsorption units as removable units, the adsorbent can be quickly recovered, disposed of, and replaced after the adsorption unit has been fully adsorbed.

[0227] By configuring a refrigerant detection sensor 324 after the first adsorption unit 321 and the second adsorption unit 322, the refrigerant detection sensor 324 can detect the refrigerant even if the adsorption unit used has broken through, and quickly switch the adsorption unit used. Furthermore, since a third adsorption unit 323 exists after the refrigerant detection sensor 324, even if the refrigerant is detected by the refrigerant detection sensor 324, it is also adsorbed by the third adsorption unit 323, and no refrigerant remains in the gas discharged into the atmosphere.

[0228] Implementation method 2.

[0229] Figure 18This is a schematic diagram of the refrigerant recovery system 10 of Embodiment 2. In the refrigerant recovery system 10B of Embodiment 1, the adsorption device (separation device) 18 includes a gas separation module 68A and an adsorption module 68B, and the desorption device 19 includes a refrigerant recovery device 14 and a recovery storage tank 16.

[0230] In contrast, in the refrigerant recovery system 10 of Embodiment 2, an adsorption module 468 is provided as an adsorption device (separation device) 418, and a pump 440 as an attraction device, a recovery storage tank 470 as a second recovery device, and a piping 58A are provided as a desorption device 419. One end of the piping 58A is connected to the adsorption module 468, and the other end is connected to the recovery storage tank 470.

[0231] The recycling process in Embodiment 2 is, in principle, the same as that in Embodiment 1. In this process, the air conditioning unit 12, the refrigerant recovery unit 14, and the recovery storage tank 16 are used to recover the condensed refrigerant. However, the refrigerant recovery system 10 does not have a three-way valve 40 and does not have the gas component circulation function as in Embodiment 1.

[0232] The adsorption module 468 of the adsorption device 418 includes an adsorption section 415. The adsorption section 415, like the adsorption section 315, includes one adsorption unit identical to the first adsorption unit 321, the second adsorption unit 322, or the third adsorption unit 323 (see reference). Figure 8 ).

[0233] Furthermore, the adsorption module 468 may have one adsorption unit, or it may have an adsorption module 68B with three adsorption units, similar to Embodiment 1. However, in Embodiment 2, the gas separation module 68A is not included.

[0234] In Embodiment 2, the mixed gas 22 containing the gaseous components of the air conditioning refrigerant and non-condensable gases contained inside the recovery storage tank 16, which has recovered the compressed condensed refrigerant, is separated in the adsorption module 468. In Embodiment 2, the gaseous component of the air conditioning refrigerant is envisioned as R-32, and the adsorbent 350 is a zeolite adsorbent. As explained in Embodiment 1, the zeolite adsorbent is suitable for reversibly adsorbing and desorbing R-32.

[0235] Furthermore, the gaseous composition of the air conditioning refrigerant can be any refrigerant other than R-32, or it can contain R-32 and one or more refrigerants other than R-32. The adsorbent 350 can be any adsorbent other than the zeolite adsorbent described in Embodiment 1, as long as it is capable of adsorbing and desorbing the air conditioning refrigerant. However, adsorbent 350 that irreversibly adsorbs (cannot desorb) the air conditioning refrigerant cannot be used. When using such an adsorbent, if the adsorbent adsorbs a certain amount of air conditioning refrigerant, the adsorbent needs to be replaced, thus increasing operating costs.

[0236] The mixed gas 22, drawn in from the gas inlet 60, flows in the delivery pipe 56. The mixed gas 22 is a gaseous component 423 (R-32) of the air conditioning refrigerant and a non-condensable gas 26. The mixed gas 22 in the delivery pipe 56 is fed into the adsorption module 468.

[0237] The adsorption module 468 includes an adsorption section 415, an inlet 490, an outlet 494, and an outlet 496. The gaseous component 423 (R-32) of the air conditioning refrigerant is adsorbed onto the adsorbent 350 (zeolite adsorbent) in the adsorption section 415. During the adsorption process, non-condensable gas 26 is discharged to the atmosphere through a pipe 424 connected to the outlet 494. During the desorption process, the gaseous component 423 of the air conditioning refrigerant adsorbed onto the adsorbent 350 is desorbed and recovered from the outlet 496 to the recovery storage tank 470 via a pipe 58A.

[0238] The adsorption device (separation device) 418 also includes a pressure detector 61, a temperature detector 62, a control valve (inlet valve) 64, and a pressure reducing valve 66 disposed on the delivery pipe 56. These functions are the same as in Embodiment 1 and are controlled by the control unit 430.

[0239] In the recovery process, the control unit 430 determines whether it is necessary to remove non-condensable gases from the recovery storage tank 16 based on the detection value DP of the pressure detector 61 and the detection value DT of the temperature detector 62. If it is determined that non-condensable gases need to be removed, the process is transferred from the recovery process to the adsorption process.

[0240] The control unit 430 receives various states detected by the adsorption module 468 as signals DS. The control unit 430 sends a signal CB1 to the inlet valve 64 to control the opening and closing of the inlet valve 64. When the control unit 430 determines that it is necessary to remove non-condensable gases, it sends a signal CB1 to control the control valve 64 to the open state; when it determines that it is not necessary to remove non-condensable gases, it sends a signal CB1 to control the control valve 64 to the closed state.

[0241] Specifically, the detected pressure DP in the recovery storage tank 16 is determined to be the ratio of the measured pressure DP to the reference pressure RP (the ratio of the measured pressure DT in the recovery storage tank 16 to the saturated vapor pressure of the recovered refrigerant). Figure 3 If the value of DP is high (DP > RP), it is determined that removal is necessary. This is the same as the determination in S104 of Implementation Method 1. Alternatively, similar to S104, it can also be determined that removal is necessary if DP > RP + α.

[0242] The control unit 430 controls the opening and closing states of each valve by sending a signal CB2 to the control valve 461, a signal CB3 to the desorption valve 462, and a signal CB4 to the exhaust valve 463. Furthermore, the control unit 430 controls the operation of the pump 440 by sending a signal CP1 to the pump 440. By driving the pump 440, the pressure inside the adsorption section 415 can be reduced to a predetermined pressure.

[0243] When the control unit 430 switches from the recovery process to the adsorption process, it controls the inlet valve 64 to open via signal CB1, the control valve 461 to open via signal CB2, the exhaust valve 463 to open via signal CB4, and the desorption valve 462 to close via signal CB3. As a result, the mixed gas 22 in the recovery storage tank 16 flows into the adsorption unit 415. Then, the gaseous component 423 (R-32) of the air conditioning refrigerant in the mixed gas 22 is adsorbed onto the adsorbent 350 in the adsorption unit 415, while the non-condensable gas 26 not adsorbed onto the adsorbent 350 is discharged to the atmosphere through the outlet 494 via the piping 424.

[0244] If the detection pressure DP falls below the reference pressure RP (saturated vapor pressure), the control unit 430 terminates the adsorption process and proceeds to the desorption process. This is the same as the determination in S112 of Embodiment 1.

[0245] During the desorption process, the control unit 430 controls the inlet valve 64 to be closed via signal CB1, controls the exhaust valve 463 to be closed via signal CB4, and controls the desorption valve 462 to be open via signal CB3. Then, the control unit 430 drives the pump 440 via signal CP1.

[0246] The pressure inside the adsorption section 415 is reduced by driving the pump 440 to draw in the gas. As a result, the gaseous component 423 of the air conditioning refrigerant adsorbed on the adsorbent 350 begins to desorb. Then, the gaseous component 423 of the air conditioning refrigerant is drawn in by the pump 440 and recovered to the recovery storage tank 470 via the piping 58A.

[0247] The concentrations of gaseous component 423 (R-32) of the air conditioning refrigerant at outlet 494 in the adsorption process and at outlet 496 in the desorption process are as follows: Figure 13 The transformation is as shown.

[0248] Next, the specific refrigerant recovery method using the refrigerant recovery system 10 will be explained. Figure 19 This is a flowchart illustrating a specific refrigerant recovery method using the refrigerant recovery system 10 in Embodiment 2.

[0249] In S400, the operator stops the air conditioning unit 12. In S401, the operator connects the refrigerant recovery device 14 and the recovery storage tank 16 to the air conditioning unit 12. In S402, the operator connects the adsorption device 418 to the recovery storage tank 16, and then connects the desorption device 419 to the adsorption device 418.

[0250] Hereinafter, S404 to S407 describe the processing of the refrigerant recovery step. In S404, the control unit 430 drives the refrigerant recovery device 14 to begin refrigerant recovery. This step can also be performed by an operator.

[0251] In S405, the control unit 430 determines whether the detection pressure DP > the reference pressure RP. In S406, the control unit 430 determines whether refrigerant remains in the refrigerant circuit 30.

[0252] If DP > RP (S405: Yes), the control unit 430 ends the refrigerant recovery process and proceeds to S408. If the control unit 430 determines that DP ≦ RP (S405: No) and refrigerant remains in the refrigerant circuit 30 (S406: Yes), it continues refrigerant recovery (S407) and returns the process to S405. That is, the control unit 430 continues refrigerant recovery while DP ≦ RP and refrigerant remains in the refrigerant circuit 30. On the other hand, if the control unit 430 determines that no refrigerant remains in the refrigerant circuit 30 (S406: No), it proceeds to S417.

[0253] Hereinafter, S408 to S412 describe the adsorption process. In S408, the control unit 430 activates the adsorption device 418 to start the adsorption process. Specifically, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to be open, and controls the desorption valve 462 to be closed, thereby starting the adsorption process. In addition, if the control valve 461 is closed in the recovery process, the control valve 461 is opened.

[0254] During the period when the control unit 430 determines that DP>RP (S409: No period), adsorption continues (S410). When the condition is determined that DP≦RP (S409: Yes), the control unit 430 stops the adsorption device 418 (S411).

[0255] If the control unit 430 determines that the refrigerant recovery from the refrigerant circuit 30 has ended (S412: Yes), the process proceeds to S413. This transfers to the desorption process. Conversely, if the control unit 430 determines that the refrigerant recovery from the refrigerant circuit 30 has not ended (S412: No), the process returns to S406. This returns to the recovery process again.

[0256] Hereinafter, S413 to S416 describe the desorption process. In S413, the control unit 430 drives the desorption device 419 to start the desorption process. Specifically, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to be closed, controls the desorption valve 462 to be open, and drives the pump 440 to start the desorption process.

[0257] Control unit 430 continues desorption (S415) until the predetermined time (desorption time) required for the desorption process has elapsed (S414: No). If the predetermined time (desorption time) has elapsed (S414: Yes), control unit 430 ends the desorption process (S416). The predetermined time (desorption time) is calculated using the same method as in S121.

[0258] In S417, the control unit 430 stops the refrigerant recovery device 14. This step can also be performed by the operator. In S418, the operator removes the piping, adsorption device 418, and desorption device 419 from the air conditioning unit 12.

[0259] In addition, not limited to the above. Figure 19 The recovery, adsorption, and desorption processes can be performed as a series of steps, as shown, or they can be performed as separate processes. Another example of the adsorption and desorption processes is shown below. Figure 20 and Figure 21 .

[0260] Figure 20 This is a flowchart illustrating the processing steps of the adsorption process. This process is related to... Figure 19 The adsorption process is basically the same.

[0261] After the recycling process is implemented, if the control unit 430 determines that the detection pressure DP > the reference pressure RP (S600), the adsorption process is started.

[0262] When the adsorption process starts, in S601, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to be open, and controls the desorption valve 462 to be closed. Additionally, in the recovery process, if the control valve 461 is closed, the control valve 461 is controlled to be open.

[0263] The control unit 430 monitors the temperature and pressure of the recovery storage tank 16 (temperature DT detected by temperature detector 62, pressure DP detected by pressure detector 61) (S602), and estimates the amount of refrigerant to be recovered (the amount of R-32 to be recovered) based on these values ​​(S603). For example, in Figure 3 In the example shown, at the detection temperature DT, the saturated vapor pressure of the recovered refrigerant (R-32) is the reference pressure RP. Furthermore, the detection pressure DP - reference pressure RP is the partial pressure of the non-condensable gas 26. Based on these pressure ratios, the control unit 430 calculates the amount of recovered refrigerant (R-32) in the recovery tank 16 as the "recovered refrigerant dosage".

[0264] In S604, the control unit 430 determines whether the current adsorption amount is less than or equal to the adsorbable amount. Here, the current adsorption amount is the amount of R-32 already adsorbed in the adsorbent 350 filled in the adsorption unit 415. The adsorbable amount is the amount of R-32 that can be adsorbed in the adsorbent 350 filled in the adsorption unit 415. Regarding the adsorbable amount, it can be determined based on the detection temperature DT and the detection pressure DP. Figure 11 The relationship between the adsorption rates of R-32, as shown, can be used for calculation. Furthermore, the current adsorption amount can be calculated using the recovered refrigeration dose calculated above. For example, if the current adsorption amount = X1 and the calculated recovered refrigeration dose = X2, the current adsorption amount after the adsorption process is completed = X1 + X2.

[0265] If the control unit 430 determines that the current adsorption capacity is greater than the adsorbable capacity (S604: No), it terminates the adsorption process. That is, if it determines that the adsorbent 350 cannot further adsorb R-32, the adsorption process is terminated. In this case, the operator needs to perform a desorption process.

[0266] In S605, the control unit 430 determines whether DP ≤ RP. This determination is the same as that in S409. If in S604 the control unit 430 determines that the current adsorption amount ≤ the adsorbable amount (S604: Yes) and the DP > RP (S605: No), it continues adsorption (S606) and returns to the process in S604. That is, adsorption continues during the period when the current adsorption amount ≤ the adsorbable amount and DP > RP. On the other hand, if in S605 the control unit 430 determines that DP ≤ RP (S605: Yes), it ends the adsorption process.

[0267] Figure 21This is a flowchart illustrating the processing steps of the desorption process. This process is related to... Figure 19 The adsorption process is basically the same.

[0268] After the refrigerant recovery in the recovery process is completed (S701), the control unit 430 calculates the pressure in the adsorption unit 415 controlled in the desorption process and the desorption time required for the desorption process (also called "specified time", which is the same as the specified time in S414) based on the adsorption amount of R-32 of the adsorbent 350 adsorbed in the adsorption unit 415 (S702), and then starts the operation of the desorption process.

[0269] like Figure 12 As shown, the amount of R-32 desorbed in the desorption process can be calculated based on the difference between the pressure inside the adsorption section 415 at the end of the adsorption process (at the beginning of the desorption process) and the pressure inside the adsorption section 415 ultimately controlled during the desorption process. In the desorption process, the concentration of R-32 at the outlet 496 of the adsorption section 415 is as follows: Figure 13 The transformation is as shown. The desorption time (the specified time) is... Figure 13 The time required for the concentration of R-32 at the outlet 496 of the adsorption section 415 to become 0 can also be estimated based on measured values.

[0270] When the adsorption process begins, in step S703, the control unit 430 controls the opening and closing of the valves. Specifically, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to be closed, and controls the desorption valve 462 to be open. This step can also be performed by an operator.

[0271] In S704, the control unit 430 drives the pump 440. This causes the R-32 adsorbed on the adsorbent 350 in the adsorption unit 415 to begin desorption. The control unit 430 continues desorption until a predetermined time (desorption time) has elapsed (S705: if not, the period is negative). As described above, when the predetermined time has elapsed, the concentration of R-32 at the outlet 496 of the adsorption unit 415 becomes 0. When the predetermined time has elapsed (S705: if yes), the control unit 430 ends the desorption process (stops the pump 440).

[0272] Next, the effects of the refrigerant recovery system 10 described above will be explained. The refrigerant recovery system 10 is a system that recovers refrigerant for air conditioning from the refrigerant circuit 30 of the air conditioning unit 12, which is a refrigeration and air conditioning equipment. The refrigerant recovery system 10 includes a recovery tank 16 as a first recovery device, an adsorption device 418, and a desorption device 419. The recovery tank 16 recovers compressed and condensed refrigerant generated by compressing and condensing the air conditioning refrigerant. The adsorption device 418 includes an adsorption module 468. The adsorption module 468 has an adsorbent 350, which adsorbs the air conditioning refrigerant gas component 423 contained in the mixed gas 22 containing the air conditioning refrigerant gas component 423 and non-condensable gas 26 contained inside the recovery tank 16, which has recovered the compressed and condensed refrigerant. The desorption device 419 desorbs the air conditioning refrigerant gas component 423 adsorbed on the adsorbent 350 and accumulates the desorbed air conditioning refrigerant gas component 423.

[0273] In this way, by activating the adsorption device 418, the mixed gas 22 containing non-condensable gas 26 inside the recovery tank 16 can be removed, and the gaseous component 423 of the air conditioning refrigerant in the mixed gas 22 can be adsorbed onto the adsorbent 350. By activating the desorption device 419, the gaseous component 423 of the air conditioning refrigerant can be desorbed from the adsorbent 350 and recovered, thus allowing the adsorbent 350 to be reused repeatedly. As a result, the amount of non-condensable gas 26 in the recovery tank 16 can be reduced, and the gas contained in the recovery tank 16 can be appropriately separated into non-condensable gas 26 and the gaseous component of the air conditioning refrigerant.

[0274] The adsorption module 468 includes an outlet 494 for discharging non-condensable gas 26 from the mixed gas 22 that has not been adsorbed by the adsorbent 350 into the atmosphere. Thus, it is possible to discharge only the non-condensable gas 26 stored in the recovery tank 16 into the atmosphere without mixing in gaseous components of the air conditioning refrigerant.

[0275] The desorption device 419 includes a recovery storage tank 470 as a second recovery device, piping 58A, and a pump 440 as a suction device. The recovery storage tank 470 stores the desorbed gaseous components 423 of the air conditioning refrigerant. One end of piping 58A is connected to the adsorption module 468, and the other end is connected to the recovery storage tank 470. The pump 440 draws the gaseous components 423 of the air conditioning refrigerant adsorbed by the adsorbent 350 and sends them to the recovery storage tank 470. Thus, regardless of the refrigerant recovery status, the gaseous components 423 of the air conditioning refrigerant adsorbed on the adsorbent 350 can be desorbed and recovered to the recovery storage tank 470.

[0276] Adsorbent 350 is a zeolite adsorbent. By using a zeolite adsorbent as adsorbent 350, it is possible to appropriately adsorb and desorb gaseous components 423 of the refrigerant used in air conditioning.

[0277] The gaseous component 423 of the refrigerant used in air conditioning is R-32. Therefore, it can appropriately adsorb and desorb R-32.

[0278] The device is configured such that it includes an adsorption module 468 as an adsorption device 418, a pump 440 as an attraction device as a desorption device 419, a recovery storage tank 470 as a second recovery device, and piping 58A. That is, it does not include a gas separation module 68A. With this structure, the device can separate R-32 in a compact and simple manner.

[0279] Implementation method 3.

[0280] Figure 22 This is a schematic diagram of the refrigerant recovery system 10A according to Embodiment 3. In the refrigerant recovery system 10 of Embodiment 2, it is configured to include an adsorption module 468 as an adsorption device 418, and a pump 440 and a recovery storage tank 470 as a desorption device 419.

[0281] In contrast, in the refrigerant recovery system 10A of Embodiment 3, the refrigerant recovery device 14 and the recovery storage tank 16 are configured as a desorption device 419. In the desorption process, the refrigerant recovery device 14 also operates as an attraction device, and the recovery storage tank 16 also operates as a second recovery device.

[0282] The refrigerant recovery device 14 and the recovery storage tank 16 are configured as a desorption device 419, which is the same as in Embodiment 1. However, unlike Embodiment 1, Embodiment 3 does not include a gas separation module 68A.

[0283] In Embodiment 3, the desorption device 419 includes a refrigerant recovery device 14 and a recovery storage tank 16, which is the same as in Embodiment 1. The gaseous component 423 of the air conditioning refrigerant drawn by the pump of the refrigerant recovery device 14 is liquefied and recovered as a compressed condensing refrigerant into the recovery storage tank 16.

[0284] Unlike embodiment 2, the three-way valve 40 is positioned between the refrigerant circuit 30 and the refrigerant recovery device 14. The three-way valve 40 includes a first port 41, a second port 42, and a third port 43. The first port 41 of the three-way valve 40 is connected to the refrigerant circuit 30. The second port 42 of the three-way valve 40 is connected to the refrigerant recovery device 14. The third port 43 of the three-way valve 40 is connected to piping 58A. Piping 58A is connected to the adsorption module 468.

[0285] The control unit 430 receives various states detected by the adsorption module 468 as signals DS. The control unit 430 sends signals CB1 to the inlet valve 64 and CB4 to the exhaust valve 463 to control the opening and closing states of each valve. The control unit 430 controls the refrigerant recovery device 14 (pump) by sending signal CP2 to the refrigerant recovery device 14. The control unit 430 switches the mode of the three-way valve 40 by sending signal CL to the three-way valve 40.

[0286] In the adsorption mode for adsorbing the gaseous component 423 of the air conditioning refrigerant into the adsorbent 350, the control unit 430 controls the inlet valve 64 to open via signal CB1, controls the exhaust valve 463 to open via signal CB4, and controls the three-way valve 40 via signal CL so that the first port 41 and the second port 42 of the three-way valve 40 are connected (normal mode).

[0287] As a result, the mixed gas 22 from the recovery storage tank 16 flows into the adsorption section 415. Furthermore, the gaseous component 423 of the air conditioning refrigerant in the mixed gas 22 is adsorbed by the adsorbent 350 in the adsorption section 415, and the unadsorbed non-condensable gas 26 is discharged to the atmosphere through the piping 424.

[0288] In the desorption mode, used to desorb the gaseous component 423 of the air conditioning refrigerant adsorbed on the adsorbent 350, the control unit 430 controls the inlet valve 64 to close via signal CB1, controls the exhaust valve 463 to close via signal CB4, and controls the three-way valve 40 to connect the second port 42 and the third port 43 via signal CL (circulation mode). Furthermore, the control unit 430 drives the pump of the refrigerant recovery device 14 via signal CP2.

[0289] As a result, the pressure inside the adsorption section 415 decreases, and the gaseous component 423 of the air conditioning refrigerant adsorbed on the adsorbent 350 desorbs. Then, the gaseous component 423 of the air conditioning refrigerant attracted by the pump driving the refrigerant recovery device 14 is liquefied and recovered as a compressed condensing refrigerant into the recovery storage tank 16.

[0290] Furthermore, in Embodiment 3, the gaseous component of the air conditioning refrigerant is also R-32, and the adsorbent 350 is a zeolite adsorbent. The gaseous component of the air conditioning refrigerant can be an air conditioning refrigerant other than R-32, or it can contain R-32 and one or more air conditioning refrigerants other than R-32. The adsorbent 350 can be any adsorbent other than the one described in Embodiment 1, as long as it is capable of adsorbing and desorbing the air conditioning refrigerant.

[0291] Next, the specific refrigerant recovery method using the refrigerant recovery system 10A will be explained. Figure 23This is a flowchart illustrating a specific refrigerant recovery method using the refrigerant recovery system 10A in Embodiment 3.

[0292] In S500, the operator stops the air conditioning unit 12. In S501, the operator connects the refrigerant recovery unit 14 and the recovery storage tank 16 to the air conditioning unit 12. In S502, the operator connects the adsorption unit 418 to the pre-stage of the refrigerant recovery unit 14 and the recovery storage tank 16.

[0293] The following steps, S503 to S507, describe the refrigerant recovery process. In S503, the control unit 430 controls the three-way valve 40 to the normal mode (the first port 41 and the second port 42 of the three-way valve 40 are connected). In S504, the control unit 430 activates the refrigerant recovery device 14 to begin refrigerant recovery. This step can also be performed by an operator.

[0294] In S505, the control unit 430 determines whether the detection pressure DP > the reference pressure RP. In S506, the control unit 430 determines whether refrigerant remains in the refrigerant circuit 30.

[0295] If DP > RP (S505: Yes), the control unit 430 ends the refrigerant recovery process and proceeds to S508. If the control unit 430 determines that DP ≦ RP (S505: No) and refrigerant remains in the refrigerant circuit 30 (S506: Yes), it continues refrigerant recovery (S507) and returns the process to S505. That is, the control unit 430 continues refrigerant recovery while DP ≦ RP and refrigerant remains in the refrigerant circuit 30. On the other hand, if the control unit 430 determines that no refrigerant remains in the refrigerant circuit 30 (S506: No), it proceeds to S517.

[0296] Hereinafter, S508 to S512 describe the adsorption process. In S508, the control unit 430 activates the adsorption device 418 to start the adsorption process. Specifically, the control unit 430 starts the adsorption process by controlling the inlet valve 64 and the exhaust valve 463 to be in the open state. In addition, in this case, the three-way valve 40 is already in the normal mode, so there is no need to change the mode of the three-way valve 40.

[0297] During the period when the control unit 430 determines that DP>RP (S509: No), adsorption continues (S510). When the control unit 430 determines that DP≦RP (S509: Yes), the control unit 430 stops the adsorption device 418 (S511).

[0298] If the control unit 430 determines that the refrigerant recovery from the refrigerant circuit 30 has ended (S512: Yes), the process proceeds to S513. This transfers to the desorption process. Conversely, if the control unit 430 determines that the refrigerant recovery from the refrigerant circuit 30 has not ended (S512: No), the process returns to S506. This returns to the recovery process again.

[0299] Hereinafter, S513 to S516 describe the desorption process. In S513, the control unit 430 drives the desorption device 419 (refrigerant recovery device 14) to start the desorption process. Specifically, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to be closed, controls the three-way valve 40 to the circulation mode (the state where the second port 42 and the third port 43 are connected), and drives the pump of the refrigerant recovery device 14 to start the desorption process.

[0300] Before the predetermined time (desorption time) required for the desorption process has elapsed (S514: No), the control unit 430 continues desorption (S515). If the predetermined time (desorption time) has elapsed (S514: Yes), the control unit 430 ends the desorption process (S516).

[0301] In S517, the control unit 430 stops the refrigerant recovery device 14. This step can also be performed by the operator. In S518, the operator removes the piping and adsorption device 418 from the air conditioning unit 12.

[0302] Next, the effects of the refrigerant recovery system 10A described above will be explained. The refrigerant recovery system 10A is a system that recovers refrigerant for air conditioning from the refrigerant circuit 30 of the air conditioning unit 12, which is a refrigeration and air conditioning device. The refrigerant recovery system 10A includes a recovery tank 16 as a first recovery device, an adsorption device 418, and a desorption device 419. The recovery tank 16 recovers compressed and condensed refrigerant generated by compressing and condensing the air conditioning refrigerant. The adsorption device 418 includes an adsorption module 468. The adsorption module 468 has an adsorbent 350, which adsorbs the air conditioning refrigerant gas component 423 contained in the mixed gas 22 containing the air conditioning refrigerant gas component 423 and non-condensable gas 26 contained inside the recovery tank 16, which has recovered the compressed and condensed refrigerant. The desorption device 419 desorbs the air conditioning refrigerant gas component 423 adsorbed on the adsorbent 350 and accumulates the desorbed air conditioning refrigerant gas component 423.

[0303] In this way, by activating the adsorption device 418, the mixed gas 22 containing non-condensable gas 26 inside the recovery tank 16 can be removed, and the gaseous component 423 of the air conditioning refrigerant in the mixed gas 22 can be adsorbed onto the adsorbent 350. By activating the desorption device 419, the gaseous component 423 of the air conditioning refrigerant can be desorbed from the adsorbent 350 and recovered, thus allowing the adsorbent 350 to be reused repeatedly. As a result, the amount of non-condensable gas 26 in the recovery tank 16 can be reduced, and the gas contained in the recovery tank 16 can be appropriately separated into non-condensable gas 26 and the gaseous component of the air conditioning refrigerant.

[0304] The adsorption module 468 includes an outlet 494 for discharging non-condensable gas 26 from the mixed gas 22 that has not been adsorbed by the adsorbent 350 into the atmosphere. Thus, it is possible to discharge only the non-condensable gas 26 stored in the recovery tank 16 into the atmosphere without mixing in gaseous components of the air conditioning refrigerant.

[0305] The desorption device 419 includes piping 58A, a refrigerant recovery device 14, and a recovery storage tank 16. One end of the piping is connected to the adsorption module 468, and the other end is connected to the desorption device 419. The refrigerant recovery device 14 generates compressed condensed refrigerant by compressing and condensing the air conditioning refrigerant. The recovery storage tank 16 recovers the compressed condensed refrigerant generated by the refrigerant recovery device 14. Thus, the gaseous component 423 of the air conditioning refrigerant desorbed from the adsorbent 350 is compressed and condensed by the refrigerant recovery device 14, and after liquefaction, it is recovered to the recovery storage tank 16. Therefore, the recovery storage tank 16 only needs to be small in size, and multiple recovery storage tanks are not required.

[0306] The adsorption unit 418 includes an inlet valve 64, a three-way valve 40, an exhaust valve 463, and a control unit 430. The inlet valve 64 is located between the recovery storage tank 16 and the adsorption module 468. The three-way valve 40 is located between the refrigerant circuit 30 and the refrigerant recovery unit 14. The exhaust valve 463 discharges non-condensable gases 26 from the mixed gas 22 that have not been adsorbed by the adsorbent 350 from the adsorption module 468 into the atmosphere. The control unit 430 controls the inlet valve 64, the three-way valve 40, and the exhaust valve 463. The three-way valve 40 includes a first port 41, a second port 42, and a third port 43. The first port 41 of the three-way valve 40 is connected to the refrigerant circuit 30. The second port 42 of the three-way valve 40 is connected to the refrigerant recovery unit 14. The third port 43 of the three-way valve 40 is connected to piping 58A. In the adsorption mode, where the gaseous component 423 of the air conditioning refrigerant is adsorbed onto the adsorbent 350, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to open, and controls the three-way valve 40 so that its first port 41 and second port 42 are connected. In the desorption mode, where the gaseous component 423 of the air conditioning refrigerant adsorbed onto the adsorbent 350 is desorbed, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to close, and controls the three-way valve so that its second port 42 and third port 43 are connected. Thus, the inlet valve 64, the three-way valve 40, and the exhaust valve 463 can be controlled to adsorb the gaseous component 423 of the air conditioning refrigerant onto the adsorbent 350 and to discharge the non-condensable gas 26 into the atmosphere, thereby enabling the desorption of the gaseous component 423 of the air conditioning refrigerant from the adsorbent 350.

[0307] Adsorbent 350 is a zeolite adsorbent. By using a zeolite adsorbent as adsorbent 350, it is possible to appropriately adsorb and desorb gaseous components 423 of the refrigerant used in air conditioning.

[0308] The gaseous component 423 of the refrigerant used in air conditioning is R-32. Therefore, it can appropriately adsorb and desorb R-32.

[0309] The various embodiments disclosed herein are also intended to be implemented in appropriate combinations to the extent that they are not technically contradictory. Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The technical scope shown in this disclosure is defined not by the description of the embodiments above but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0310] Label Explanation

[0311] 10, 10A, 10B Refrigerant recovery system; 12 Air conditioning unit; 14 Refrigerant recovery device; 16 Recovery storage tank; 18 Separation device (adsorption device); 19 Desorption device; 20 Recovery tank; 22, 24 Mixed gas; 23 First gaseous component of air conditioning refrigerant; 25 Second gaseous component of air conditioning refrigerant (gas composition of air conditioning refrigerant); 26 Non-condensable gas; 28 Water; 29 Other gaseous components; 30 Refrigerant circuit; 32 Liquid receiver; 34 Maintenance port; 36, 90A, 90B Inlet; 37, 61, 70 Pressure detector; 38, 96A Outlet; 40 Three-way valve; 41 Port 1; 42 Port 2; 43 Port 3; 46 Liquid inlet / outlet; 48 Gas inlet / outlet; 49 Branch piping; 50 Connecting piping; 52 Front piping; 54 Post-piping; 56 Sending piping; 57A, 57B piping; 58A, 58B, 58C Re-sending piping; 59, P1, P2 piping; 60 Gas inlet; 62 Temperature detector; 64 Control valve (inlet valve); 66 Pressure reducing valve; 68 Gas separation device; 68A Gas separation module; 68B Adsorption module; 72 Pressure regulator; 74 Gas outlet; 76 Sending controller; 78 Re-sending controller; 80 Three-way valve controller; 88A Frame; 92A Separation membrane; 94, 94A, 94B Discharge outlet; 97, 97A Pressure controller; 98A First pressure regulator; 98B Second pressure regulator; 99A First check valve; 100 Input section; 102, 102A Storage section; 104 Reference pressure acquirer; 106 Pressure reducing valve controller; 108, 118 Detector; 110 Refrigerant recovery information; 112 Pressure characteristics; 120 Pressure threshold; 122 Duration; 211, 211A Pressure acquisition device; 212 First pressure controller; 213 Second pressure controller; 214 First pressure information; 215 Second pressure information; 253 Sensor; 254 Bypass controller; 315 Adsorption unit; 320 Switching valve; 321 First adsorption unit; 322 Second adsorption unit; 323 Third adsorption unit; 324 Refrigerant detection sensor; 330 Control unit; 350 Adsorbent; 402 Three-way valve; 411 First port; 412 Second port; 413 Third port; 415 Adsorption unit; 418 Adsorption device; 419 Desorption device; 423 Gas composition of air conditioning refrigerant; 424 Piping; 430 Control unit; 440 Pump; 461 Control valve; 462 Desorption valve; 463 Exhaust valve; 468 Adsorption module; 470 Recovery tank; 490 Inlet; 494 Outlet; 496 Outlet.

Claims

1. A refrigerant recovery system for recovering refrigerant for air conditioning from the refrigerant circuit of a refrigeration and air conditioning unit. The refrigerant recovery system includes: The first recovery device recovers compressed condensed refrigerant generated by compressing and condensing the air conditioning refrigerant; An adsorption device comprising an adsorption module having an adsorbent that adsorbs and recovers the gaseous components of the air conditioning refrigerant contained within a first recovery device for the compressed condensing refrigerant, in a mixture of gaseous components of the air conditioning refrigerant and non-condensable gases; and A desorption device that desorbs the gaseous components of the air conditioning refrigerant adsorbed on the adsorbent and accumulates the desorbed gaseous components of the air conditioning refrigerant.

2. The refrigerant recovery system according to claim 1, wherein, The adsorption module includes an outlet for discharging the non-condensable gas in the mixed gas that has not been adsorbed by the adsorbent into the atmosphere.

3. The refrigerant recovery system according to claim 1 or 2, wherein, The desorption device comprises: The second recovery device accumulates the gaseous components of the desorbed air conditioning refrigerant; Piping, one end of which is connected to the adsorption module, and the other end of which is connected to the second recovery device; and An attraction device that attracts the gaseous components of the air conditioning refrigerant adsorbed on the adsorbent and sends them out to the second recovery device.

4. The refrigerant recovery system according to claim 1, wherein, The desorption device comprises: The piping has one end connected to the adsorption module and the other end connected to the desorption device; A refrigerant recovery device generates compressed and condensed refrigerant by compressing and condensing the refrigerant used in the air conditioner; as well as The first recovery device recovers the compressed condensed refrigerant generated by the refrigerant recovery unit.

5. The refrigerant recovery system of claim 4, wherein, The adsorption device comprises: An inlet valve is configured between the first recovery device and the adsorption module; A three-way valve is disposed between the refrigerant circuit and the refrigerant recovery device; An exhaust valve discharges the non-condensable gases in the mixed gas that have not been adsorbed by the adsorbent from the adsorption module into the atmosphere; as well as The control unit controls the inlet valve, the three-way valve, and the exhaust valve. The three-way valve includes a first port, a second port, and a third port. The first port of the three-way valve is connected to the refrigerant circuit, the second port of the three-way valve is connected to the refrigerant recovery device, and the third port of the three-way valve is connected to the piping. In the adsorption mode for adsorbing the gaseous components of the air conditioning refrigerant onto the adsorbent, the control unit controls the inlet valve and the exhaust valve to open, and controls the three-way valve so that the first port and the second port of the three-way valve are in a connected state. In the desorption mode for desorbing the gaseous components of the air conditioning refrigerant adsorbed on the adsorbent, the control unit controls the inlet valve and the exhaust valve to close, and controls the three-way valve so that the second port and the third port of the three-way valve are connected.

6. The refrigerant recovery system according to claim 1, wherein, The adsorption device further includes a gas separation module, which comprises a separation membrane that separates the mixed gas into a first gaseous component of the air conditioning refrigerant and a second mixed gas composed of a second gaseous component of the air conditioning refrigerant and the non-condensable gas. The adsorbent in the adsorption module adsorbs the second gas component of the air conditioning refrigerant in the second mixed gas separated by the gas separation module. The desorption device comprises: A refrigerant recovery device that generates compressed and condensed refrigerant by compressing and condensing the air conditioning refrigerant; and The first recovery device recovers the compressed condensed refrigerant generated by the refrigerant recovery unit. The refrigerant recovery system also includes a refill piping, which comprises: The first recharge piping is used to supply the first gas component of the air conditioning refrigerant separated by the gas separation module. A second resupply pipe, which supplies the second gaseous component of the air conditioning refrigerant after desorption from the adsorbent; and The third refill pipe mixes the first gas component with the second gas component and then refills it between the refrigerant circuit and the refrigerant recovery device.

7. The refrigerant recovery system according to any one of claims 1 to 6, wherein, The adsorbent is a zeolite adsorbent.

8. The refrigerant recovery system according to any one of claims 1 to 7, wherein, The gaseous composition of the refrigerant used in the air conditioner is R-32.

9. A refrigerant recovery method for recovering refrigerant for air conditioning from the refrigerant circuit of a refrigeration and air conditioning unit, wherein, The refrigerant recovery method comprises the following steps: The first recycling equipment recycles compressed condensed refrigerant generated by compressing and condensing the air conditioning refrigerant; The adsorbent in the adsorption module of the adsorption device adsorbs and recovers the gaseous components of the air conditioning refrigerant contained in the first recovery device of the compressed condensing refrigerant, which are composed of gaseous components of the air conditioning refrigerant and non-condensable gases. as well as The desorption device desorbs the gaseous components of the air conditioning refrigerant adsorbed on the adsorbent and accumulates the desorbed gaseous components of the air conditioning refrigerant.

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