WO2025109719A1 - Refrigerant recovery system and refrigerant recovery method - Google Patents

Abstract

A first recovery apparatus (16) recovers compressed condensed refrigerant generated by compressing and condensing an air-conditioning refrigerant. An adsorption device (418) includes an adsorption module (468). The adsorption module (468) has an adsorbent (350) that adsorbs an air-conditioning-refrigerant gas component (423) from a mixed gas (22) comprising the air-conditioning-refrigerant gas component (423) and a non-condensable gas (26), the mixed gas (22) being contained inside the first recovery apparatus (16) by which the compressed condensed refrigerant is recovered. A desorption device (19) desorbs the air-conditioning-refrigerant gas component (423) adsorbed by the adsorbent (350) and accumulates the desorbed air-conditioning-refrigerant gas component (423).

Description

Refrigerant recovery system and refrigerant recovery method

This disclosure relates to a refrigerant recovery system and a refrigerant recovery method.

Refrigeration and air conditioning equipment (equipment that uses refrigerant) such as freezers and air conditioners are equipped with the following on the circulation path of the refrigerant that transports thermal energy: an air conditioning compressor that compresses the vaporized gas refrigerant to heat and pressurize it; an air conditioning condenser that cools the gas refrigerant that has been heated and pressurized by the air conditioning compressor with outside air or the like to liquefy it; an expansion valve that expands the refrigerant (liquid refrigerant) liquefied by the air conditioning condenser to gasify it; a refrigerant recovery condenser that liquefies the vaporized refrigerant (gas refrigerant) by the expansion valve; and an accumulator that stores the refrigerant (liquid refrigerant) liquefied by the refrigerant recovery condenser. The refrigerant plays a role in transporting thermal energy, releasing heat to the outside in the air conditioning condenser while receiving heat from the outside air or the like after passing through the expansion valve.

The various refrigerants used in refrigeration and air conditioning equipment have high global warming potential and ozone depletion potential, so their emission into the atmosphere is regulated. Therefore, it is mandatory to recover the refrigerant filled in the refrigeration and air conditioning equipment without leaking it into the atmosphere, especially when replacing the refrigerant or maintaining or disposing of the equipment. At the same time, there is also a shift to refrigerants with less environmental impact, and in recent years, the use of HFCs (hydrofluorocarbons) and other refrigerants as alternative fluorocarbons has become mainstream. Examples of HFCs include R134A or R32 (also written as "R-32") as simple refrigerants, and R410A or R407C as mixed refrigerants.

A refrigerant recovery device is used to recover the refrigerant. In the refrigerant recovery device, the refrigerant present in the refrigerant circuit, including the accumulator in the refrigeration and air conditioning equipment, is vaporized, and the gas refrigerant is then sucked in by a compressor in the refrigerant recovery device and adiabatically compressed. The adiabatically compressed gas refrigerant is liquefied by a condenser in the refrigerant recovery device and recovered as liquid refrigerant in a recovery cylinder. The amount of recovered refrigerant is measured by a weighing scale.

When refrigerant in equipment that uses refrigerant is recovered into a recovery cylinder by a refrigerant recovery device, if non-condensable gases whose main component is air, such as nitrogen (N2) or oxygen (O2), get mixed into the recovery system, the non-condensable gases will also be recovered into the recovery cylinder. Since non-condensable gases do not condense in the recovery cylinder and exist as compressed gases, the pressure and temperature inside the recovery cylinder rise as the amount of liquid refrigerant in the recovery cylinder increases and the volume of the gas phase decreases. As a result, the internal pressure of the recovery cylinder rises, making it difficult to fill it with liquid refrigerant, and the speed at which refrigerant is recovered into the recovery cylinder decreases. This means that it takes a lot of time to recover all of the refrigerant.

In response to this problem, the refrigerant recovery system of Patent Document 1 is equipped with a gas separation module that separates the mixed gas of gas refrigerant and non-condensable gas accumulated in the recovery cylinder, and is configured to send the mixed gas in the recovery cylinder to the gas separation module for separation, discharge the separated non-condensable gas into the atmosphere, and re-send the gas refrigerant to the refrigerant recovery device. In this way, the refrigerant recovery system of Patent Document 1 reduces the non-condensable gas in the recovery cylinder while maintaining the connections to the recovery cylinder, refrigerant recovery device, and refrigeration and air conditioning equipment.

Patent No. 7029025

However, when using the refrigerant recovery system of Patent Document 1, there are cases where it is difficult to separate the mixed gas contained in the recovery equipment (recovery cylinder) into a non-condensable gas and a gas refrigerant using the gas separation module. For example, when R32 is used as the refrigerant, it may not be possible to completely separate the non-condensable gas and R32 using the gas separation module.

Therefore, the object of this disclosure is to provide a refrigerant recovery system and a refrigerant recovery method that can effectively separate the gas contained in the recovery device into non-condensable gas and gas refrigerant while reducing the non-condensable gas in the recovery device.

The refrigerant recovery system disclosed herein is a system that recovers air-conditioning refrigerant from the refrigerant circuit of a refrigeration and air-conditioning device. 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 produced by compressing and condensing the air-conditioning refrigerant. The adsorption device includes an adsorption module. The adsorption module has an adsorbent that adsorbs the gas components of the air-conditioning refrigerant from a mixed gas consisting of the gas components of the air-conditioning refrigerant and non-condensable gases contained inside the first recovery device that recovered the compressed and condensed refrigerant. The desorption device desorbs the gas components of the air-conditioning refrigerant adsorbed by the adsorbent, and accumulates the desorbed gas components of the air-conditioning refrigerant.

The refrigerant recovery method disclosed herein is a method for recovering air-conditioning refrigerant from the refrigerant circuit of a refrigeration and air-conditioning device. The refrigerant recovery method includes the steps of: a first recovery device recovering compressed and condensed refrigerant produced by compressing and condensing the air-conditioning refrigerant; an adsorbent in an adsorption module of an adsorption device adsorbing the gas component of the air-conditioning refrigerant from a mixed gas of the gas component of the air-conditioning refrigerant and a non-condensable gas contained inside the first recovery device that recovered the compressed and condensed refrigerant; and a desorption device desorbing the gas component of the air-conditioning refrigerant adsorbed by the adsorbent and storing the desorbed gas component of the air-conditioning refrigerant.

According to the present disclosure, it is possible to effectively separate the gas contained in the recovery device into a non-condensable gas and a gas refrigerant while reducing the amount of non-condensable gas in the recovery device.

A schematic diagram of a refrigerant recovery system 10B related to embodiment 1. FIG. 7 is a block diagram of the dispatch controller 76. FIG. 4 is a diagram showing an example of pressure characteristics of each refrigerant. FIG. 2 is a block diagram of a three-way valve controller 80. FIG. 13 is a block diagram of a pressure controller 97A. 13 is a diagram for explaining a set pressure PA of the pressure difference between inside and outside a separation membrane 92A. FIG. 1A and 1B are diagrams illustrating the molecular sieving principle of a separation membrane 92A formed of an inorganic separation membrane. 3 is a diagram showing details of a first suction unit 321, a second suction unit 322, and a third suction unit 323. FIG. 1 is a diagram showing an example of how a refrigerant is adsorbed by an adsorbent 350. FIG. FIG. 13 is a diagram showing another example in which a refrigerant is adsorbed by an adsorbent 350. 1 is a graph showing the relationship between the degree of vacuum and the adsorption rate of R-32 onto zeolite. 1 is a graph showing the relationship between the degree of vacuum and the desorption rate of R-32 onto zeolite. 1 is a graph showing the change in outlet concentration of R-32 during the adsorption process and the desorption process. A flowchart showing a specific refrigerant recovery method using the refrigerant recovery system 10B in embodiment 1. A flowchart showing a specific refrigerant recovery method using the refrigerant recovery system 10B in embodiment 1. 5 is a flowchart showing a first three-way valve control. 10 is a flowchart showing a second three-way valve control. A schematic diagram of a refrigerant recovery system 10 related to embodiment 2. A flowchart showing a specific refrigerant recovery method using the refrigerant recovery system 10 in embodiment 2. 10 is a flowchart showing a processing procedure of an adsorption step. 10 is a flowchart showing a procedure of a desorption process. A schematic diagram of a refrigerant recovery system 10A relating to embodiment 3. A flowchart showing a specific refrigerant recovery method using the refrigerant recovery system 10A in embodiment 3.

The embodiments will be described in detail below with reference to the attached drawings. The configurations described below are examples for explanatory purposes and can be modified as appropriate to suit the specifications of the system, device, etc. Furthermore, when multiple embodiments or variations are included below, it is assumed from the beginning that their characteristic parts will be used in appropriate combination. The same elements are given the same symbols in all drawings, and duplicate explanations will be omitted.

Embodiment 1.
Fig. 1 is a schematic diagram of a refrigerant recovery system 10B according to embodiment 1. In the figure, solid lines indicate pipes through which a fluid flows, and dashed lines indicate control lines inputting and outputting to each controller.

Refrigerant recovery system 10B is a system for recovering air-conditioning refrigerant from refrigeration and air-conditioning equipment and filling it into recovery cylinder 16. As described below, refrigerant recovery system 10B has the function of adsorbing the gas components of the air-conditioning refrigerant contained in the mixed gas accumulated inside recovery cylinder 16 to adsorbent 350 of separation device (also called "adsorption device") 18, and further desorbing the gas components of the air-conditioning refrigerant adsorbed to adsorbent 350 by desorption device 19 and recovering them again in recovery cylinder 16.

Below, an example of recovering air-conditioning refrigerant from an air-conditioning device 12 as a refrigeration and air-conditioning device will be described, but the refrigerant recovery system 10B can be applied to the recovery of refrigerant from any device that uses refrigerant. Air-conditioning refrigerant transports thermal energy and changes phase between liquid and gas phases during operation of the refrigeration and air-conditioning device, thereby achieving at least one of the cooling and heating functions of the air, etc., in the refrigeration and air-conditioning device.

The refrigerant recovery system 10B includes a refrigerant recovery device 14, a recovery cylinder 16 as a first recovery device, a gas separation device 68, return pipes 58A to 58C as first to third return pipes, and three-way valves 40 and 402.

The refrigerant recovery device 14 draws in the air-conditioning refrigerant from the refrigerant circuit 30 of the air-conditioning device 12, compresses it adiabatically, and condenses the compressed refrigerant to liquid form to produce compressed condensed refrigerant. The recovery cylinder 16 recovers the compressed condensed refrigerant produced by the refrigerant recovery device 14.

The gas separation device 68 separates the mixed gas 22, which is composed of the gas components of the air-conditioning refrigerant and non-condensable gas contained inside the recovery cylinder 16 from which the compressed condensed refrigerant has been recovered, 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 the separation device 18 or the adsorption device 18. The refrigerant recovery device 14 and the recovery cylinder 16 constitute the desorption device 19.

The reason why both the gas separation module 68A and the adsorption module 68B are used is because there are cases where the air conditioning refrigerant and the non-condensable gases cannot be completely separated by only one module.

The re-transmission pipes 58A and 58C re-transmit the gas components separated by the gas separation module 68A between the refrigerant circuit 30 and the refrigerant recovery device 14. In the evaporation promotion mode, the gas components separated by the gas separation module 68A are sent to the refrigerant circuit 30. This increases the temperature of the refrigerant in the refrigerant circuit 30, promoting the evaporation of the refrigerant and improving the refrigerant recovery speed when refrigerant recovery is resumed. In the circulation mode, the gas components separated by the gas separation module 68A are sent to the refrigerant recovery device 14. This causes the recovery process of the gas components of the air-conditioning refrigerant separated by the gas separation module 68A to be performed again.

The three-way valve 40 is disposed between the refrigerant circuit 30 and the refrigerant recovery device 14. The air conditioner 12 includes a service port 34 that is connected to the refrigerant circuit 30.

The refrigerant circuit 30 includes an accumulator 32 in which liquid refrigerant is stored. The refrigerant recovery device 14 draws in the gas refrigerant that has been vaporized from the liquid refrigerant in the accumulator 32 through a service port 34.

The refrigerant recovery device 14 includes a compressor and a condenser, and can be realized by a fluorocarbon recovery machine that is widely available on the market. The refrigerant recovery device 14 includes an inlet 36 (inlet) that takes in the air-conditioning refrigerant from the refrigerant circuit 30, an outlet 38 that discharges the compressed and condensed refrigerant, and a pressure detector 37 that detects the pressure of the air-conditioning refrigerant at the inlet 36.

The recovery cylinder 16 includes a liquid inlet/outlet 46 through which the compressed condensed refrigerant from the refrigerant recovery device 14 is introduced into the recovery cylinder 16, and a gas inlet/outlet 48 through which the mixed gas 22 in the recovery cylinder 16 is discharged. The mixed gas 22 of non-condensable gas and re-vaporized gas refrigerant to the gas volume amount is retained in the head space portion of the recovery cylinder 16.

The three-way valve 40 includes a first port 41, a second port 42, and a third port 43. The service port 34 of the air conditioner 12 and the first port 41 of the three-way valve 40 are connected by a connection pipe 50. The second port 42 of the three-way valve 40 and the inlet 36 of the refrigerant recovery device 14 are connected by a front pipe 52. The third port 43 of the three-way valve 40 is connected to the re-transmission pipe 58C.

The outlet 38 of the refrigerant recovery device 14 and the liquid inlet/outlet 46 of the recovery cylinder 16 are connected by a rear pipe 54. When performing general refrigerant recovery, the first port 41 and the second port 42 of the three-way valve 40 are in communication (normal mode).

When a valve malfunctions, when pipes corrode, when the refrigerant decomposes, or when air gets in during refrigerant repairs, non-condensable gases mainly composed of nitrogen or air (nitrogen, oxygen, etc.) can become mixed into the air conditioning refrigerant (hereinafter simply referred to as refrigerant) of the air conditioner 12. When non-condensable gases are sucked into the refrigerant recovery device 14 together with the refrigerant during refrigerant recovery, the non-condensable gases are not condensed in the refrigerant recovery device 14 and are filled into the recovery cylinder 16 as a gas. As a result, the internal pressure of the recovery cylinder 16 rises, making it difficult to fill it with liquid refrigerant, and the speed at which the refrigerant is recovered into the recovery cylinder 16 decreases.

To deal with this, the refrigerant recovery system 10B is equipped with a separation device (adsorption device) 18 that removes the non-condensable gas in the recovery cylinder 16 and adsorbs the second gas component 25 of the air-conditioning refrigerant in the adsorption section 315, and a desorption device 19 that desorbs and recovers the adsorbed second gas component 25 of the air-conditioning refrigerant. In the recovery cylinder 16, a mixed gas 22 is generated that is a mixture of the non-condensable gas and the gas component of the air-conditioning refrigerant in which some of the liquid refrigerant has been re-vaporized relative to the gas volume.

The separation device 18 further includes a gas inlet 60 and a delivery pipe 56. The gas inlet 60 is connected to the gas inlet 48 of the recovery cylinder 16. The gas inlet 60 extracts the mixed gas 22 that is retained in the head space of the recovery cylinder 16. The mixed gas 22 taken in from the gas inlet 60 flows into the delivery pipe 56.

The gas separation device 68 (separation device 18) separates the air conditioning refrigerant as a gas component from the mixed gas 22 inside the recovery cylinder 16 that has recovered the compressed condensed refrigerant. The mixed gas 22 is sent to the gas separation device 68 through the delivery pipe 56. The gas separation device 68 separates the mixed gas 22 into multiple components.

The re-transmission pipes 58A and 58C are connected to the gas separation device 68. The re-transmission pipes 58A and 58C re-transmit the first gas component 23 of the air-conditioning refrigerant separated by the gas separation module 68A between the refrigerant recovery device 14 and the refrigerant circuit 30.

The gas separation device 68 includes a gas separation module 68A located in the front stage and an adsorption module 68B located in the rear stage.

The gas separation module 68A includes an inlet 90A, a separation membrane 92A, an outlet 94A, and an outlet 96A. The inlet 90A takes in the mixed gas 22.

Separation membrane 92A separates mixed gas 22 into a first gas component 23 of the air-conditioning refrigerant and mixed gas 24 (second mixed gas) consisting of a second gas component 25 of the air-conditioning refrigerant and a non-condensable gas 26. When a mixed gas containing a large amount of non-condensable gas flows into separation membrane 92A, non-condensable gas 26 flows not only toward discharge port 94A but also toward outlet 96A. As separation is repeated, the amount of non-condensable gas 26 flowing toward discharge port 94A increases, and the amount flowing toward outlet 96A decreases.

The outlet 94A discharges the mixed gas 24 that has permeated the separation membrane 92A into the pipe 59. The outlet 96A discharges the first gas component 23 of the air-conditioning refrigerant that has not permeated the separation membrane 92A.

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

The first end of the re-transmission pipe 58A is connected to the outlet 96A of the gas separation module 68A. The second end of the re-transmission pipe 58A is connected to the first end of the re-transmission pipe 58C. The second end of the re-transmission pipe 58C is connected to the third port 43 of the three-way valve 40 as a gas outlet 74. As will be described later, the second end of the re-transmission pipe 58A and the second end of the re-transmission pipe 58B are connected to the second end of the re-transmission pipe 58C, but under normal circumstances, gas does not flow in from the re-transmission pipe 58B, and gas flows from the re-transmission pipe 58A to the re-transmission pipe 58C.

The adsorption module 68B includes an inlet 90B, an outlet 94B, pipes 57A and 57B, a three-way valve 402, and an adsorption section 315. The inlet 90B takes in the mixed gas 24.

The adsorption section 315 adsorbs the second gas component 25 of the air-conditioning refrigerant from the mixed gas 24 onto the adsorbent. The discharge port 94B discharges the non-condensable gas 26 that has not been adsorbed by the adsorption section 315.

The three-way valve 402 includes a first port 411, a second port 412, and a third port 413. The discharge port 94B and the first port 411 of the three-way valve 402 are connected by a pipe 57A. The second port 412 of the three-way valve 402 is connected to a pipe 57B. The third port 413 of the three-way valve 402 is connected to a pipe 58B.

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

On the other hand, when performing 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 communicating state. Here, the desorption process refers to the process of desorbing and recovering the second gas component 25 of the air-conditioning refrigerant adsorbed by the adsorbent 350 in the adsorption module 68B. In this case, the gas flowing through the pipe 57A (the desorbed second gas component 25) flows to the refrigerant recovery device 14 side via the re-transmission pipes 58B and 58C.

Below, the process that is different from the adsorption process and the desorption process and that recovers the air conditioning refrigerant from the refrigerant circuit 30 of the air conditioner 12 and recovers it in the recovery cylinder 16 is referred to as the "recovery process."

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

The first pressure regulator 98A adjusts the pressure difference between inside and outside the separation membrane 92A of the gas separation module 68A. The first pressure regulator 98A is disposed downstream of 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.

The first check valve 99A is disposed 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 into the separation membrane 92A.

As will be explained below, detectors, valves, etc. are arranged in the delivery pipe 56 and the return pipe 58A, but the refrigerant recovery system can be configured by omitting some of these. The basic refrigerant recovery method for the refrigerant recovery system, including such a configuration, comprises the following steps (1) to (5).

(1) In the recovery process, the first port 41 and the second port 42 of the three-way valve 40 are connected (hereinafter referred to as normal mode), the air conditioning refrigerant in the refrigerant circuit 30 is guided to the refrigerant recovery device 14 through the connection pipe 50 and the front pipe 52, and the air conditioning refrigerant is compressed and condensed using the refrigerant recovery device 14 to generate compressed and condensed refrigerant.

(2) A recovery step in which the compressed condensed refrigerant produced by the refrigerant recovery device 14 is recovered in the recovery cylinder 16 through the rear piping 54 during the recovery process.

(3) In the adsorption process, the first port 411 and the second port 412 of the three-way valve 402 are connected to each other, and the mixed gas 22 contained inside the recovery cylinder 16 is led to the gas separation device 68 through the delivery pipe 56, and the mixed gas 22 is separated into multiple components using the gas separation device 68 (separation device 18).

(4) 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), and the first gas component 23 of the air-conditioning refrigerant that did not permeate the separation membrane 92A is re-transmitted between the refrigerant recovery device 14 and the refrigerant circuit 30 through the re-transmission pipe 58A and the front pipe 52.

The separation step (3) above includes the following two steps: (3A) A first separation step in which the mixed gas 22 is separated by the separation membrane 92A of the gas separation module 68A into a first gas component 23 of the air-conditioning refrigerant and a mixed gas 24 (second mixed gas) consisting of a second gas component 25 of the air-conditioning refrigerant and a non-condensable gas 26.

(3B) A second separation step (also referred to as the "adsorption step") in which the second gas component 25 of the air-conditioning refrigerant is adsorbed in the adsorption section 315 (adsorbent 350) of the adsorption module 68B from the mixed gas 24 (second mixed gas) separated by the separation membrane 92A of the gas separation module 68A, and the non-condensable gas 26 of the mixed gas 24 (second mixed gas) that was not adsorbed in the adsorption section 315 is released into the atmosphere from the release port 94B.

(5) In the desorption process, the first port 411 and the second port 412 of the three-way valve 402 are connected to each other, the refrigerant recovery device 14 is operated to desorb the second gas component 25 adsorbed in the adsorption section 315 (adsorbent 350), and the desorbed second gas component 25 is stored in the recovery cylinder 16.

Continuing with the explanation of the refrigerant recovery system 10B in Figure 1, the separation device 18 further includes a pressure detector 61, a temperature detector 62, a control valve (also referred to as an "inlet valve") 64, and a pressure reducing valve 66, which are arranged in the delivery pipe 56.

The pressure detector 61 and temperature detector 62 on the delivery pipe 56 are located closer to the recovery cylinder 16 than the control valve 64 and detect the pressure and temperature inside the recovery cylinder 16.

The separation device 18 further includes a pressure detector 70 and a pressure regulator 72 arranged in the return pipe 58C.

The pressure detector 70 on the re-transmission pipe 58C detects the pressure in the re-transmission pipe 58C upstream of the pressure regulator 72 (the gas separation device 68 side). The pressure regulator 72 adjusts the pressure in the re-transmission pipe 58C downstream of the pressure regulator 72 (the gas outlet 74 side).

The separation device 18 further includes a delivery controller 76, a retransmission controller 78, a three-way valve controller 80, and a pressure controller 97A.

The dispatch controller 76, retransmission controller 78, three-way valve controller 80, pressure controller 97A, and control unit 330 are controllers, and are, for example, microcomputers equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), flash memory, and input/output ports. These controllers may be realized by a single common microcomputer. Furthermore, these controllers may include an ASIC (Application Specific Integrated Circuit) or the like instead of or together with a microcomputer.

During the recovery process, the delivery controller 76 determines whether or not it is necessary to remove non-condensable gas from the recovery cylinder 16 based on the detection value DP of the pressure detector 61 and the detection value DT of the temperature detector 62. When the delivery controller 76 determines that removal is necessary, it opens the control valve 64, and when it determines that removal is not necessary, it closes the control valve 64. When the control valve 64 changes to an open state, the process transitions from the recovery process to the adsorption process.

When the control valve 64 is closed (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 in a connected state (normal mode).

When the control valve 64 is open (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 connect the first port 41 and the third port 43 (hereinafter referred to as the vaporization promotion mode). In this way, in the embodiment of FIG. 1, a vaporization promotion mode is added to the basic refrigerant recovery method.

The normal mode controlled in the recovery process is a mode in which refrigerant is recovered from the air conditioning device 12 to the recovery cylinder 16. The circulation mode controlled in the adsorption process is a mode in which a circulation loop is formed by the separation device 18, the refrigerant recovery device 14, and the recovery cylinder 16, and the mixed gas 22 in the recovery cylinder 16 is repeatedly sent to the gas separation device 68 to remove the non-condensable gas in the recovery cylinder 16. The circulation mode is also controlled in the desorption process. In this case, the second gas component 25 adsorbed to the adsorbent 350 in the gas separation device 68 is desorbed and recovered in the recovery cylinder 16.

The evaporation promotion mode controlled in the adsorption process is a mode in which, when there is a possibility of low-temperature condensation of the refrigerant in the refrigerant circuit 30 of the air conditioning device 12, a portion of the mixed gas 22 in the recovery cylinder 16 is sent from the separation device 18 into the refrigerant circuit 30, raising the temperature of the refrigerant in the refrigerant circuit 30 and promoting evaporation of the refrigerant. The gas refrigerant that has passed through the refrigerant recovery device 14 is adiabatically compressed, so its temperature is higher than when it flows into the refrigerant circuit 30, i.e., into the refrigerant recovery device 14. Therefore, the refrigerant that enters the recovery cylinder 16 from the refrigerant recovery device 14 has a higher temperature.

The pressure controller 97A controls the first pressure regulator 98A to adjust the pressure difference between inside and outside the separation membrane 92A. The pressure controller 97A also controls the second pressure regulator 98B to adjust the pressure during adsorption in the adsorption section 315.

FIG. 2 is a block diagram of the dispatch controller 76. The dispatch controller 76 includes a reference pressure acquirer 104, a pressure reducing valve controller 106, and a determiner 108. The separation device 18 includes an input unit 100 such as a keypad or a barcode reader, and a storage unit 102 such as a flash memory. The dispatch controller 76 is electrically connected to the input unit 100 and the storage unit 102. The memory in the dispatch controller 76 may be used as the storage unit 102.

Before refrigerant recovery, recovered refrigerant 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 memory unit 102. For example, a barcode indicating the type of refrigerant used in air conditioner 12, which is attached to the surface of the housing of air conditioner 12, is read by a barcode reader serving as input unit 100, and recovered refrigerant information 110 is stored in memory unit 102. Memory unit 102 also pre-stores the characteristics of saturated vapor pressure versus temperature (hereinafter referred to as pressure characteristics 112) for each of multiple types of refrigerant.

Figure 3 shows an example of the pressure characteristics of each refrigerant. Figure 3 shows the pressure characteristics of refrigerants A, B, C, and D.

The reference pressure acquirer 104 receives the detected temperature DT (temperature inside the recovery cylinder 16) of the temperature detector 62 on the dispatch pipe 56. The reference pressure acquirer 104 reads the pressure characteristics 112 corresponding to the recovered refrigerant indicated by the recovered refrigerant information 110 from the memory unit 102, and acquires the saturated vapor pressure of the recovered refrigerant (refrigerant A in the example of FIG. 3) at the detected temperature DT (temperature inside the recovery cylinder 16) as the reference pressure RP, as shown in FIG. 3. The reference pressure acquirer 104 then outputs the reference pressure RP to the determiner 108.

The reference pressure RP and the detected pressure DP (pressure in the recovery cylinder 16) of the pressure detector 61 on the delivery pipe 56 are input to the determiner 108. Here, as shown in FIG. 3, if the detected pressure DP is higher than the reference pressure RP (saturated vapor pressure of the recovered refrigerant), it indicates that non-condensable gas is mixed in the recovery cylinder 16. Therefore, when the detected pressure DP is higher than the reference pressure RP (hereinafter also referred to as a high-pressure state), the determiner 108 controls the control valve 64 to an open state and sends the mixed gas 22 in the recovery cylinder 16 to the gas separation device 68. On the other hand, when the high-pressure state is not reached, the determiner 108 keeps the control valve 64 closed. The determiner 108 outputs a removal signal indicating whether or not non-condensable gas is being removed. The removal signal is a signal that is Low when the control valve 64 is closed and is High when the control valve 64 is open.

The pressure reducing valve controller 106 receives the detected pressure DP (pressure inside the recovery cylinder 16) of the pressure detector 61 on the delivery pipe 56. When the control valve 64 opens and the mixed gas 22 in the recovery cylinder 16 is sent to the gas separation device 68, the pressure reducing valve controller 106 controls the pressure reducing valve 66 based on the detected pressure DP so that the separation membrane 92A of the gas separation device 68 is not damaged by the pressure inside the recovery cylinder 16. By controlling the pressure reducing valve 66, the pressure inside the pipe downstream of the pressure reducing valve 66 (on the gas separation device 68 side) is adjusted.

FIG. 4 is a block diagram of the three-way valve controller 80. The three-way valve controller 80 includes a determiner 118. The three-way valve controller 80 is electrically connected to an input unit 100 such as a keypad, and a storage unit 102 such as a flash memory. The memory within the three-way valve controller 80 may be used as the storage unit 102.

Before refrigerant recovery, a pressure threshold 120 as a transition condition to the evaporation promotion mode and a duration 122 of the evaporation promotion mode are input from the input unit 100 and stored in the memory unit 102. The determiner 118 receives the removal signal, the detected pressure DPS of the pressure detector 37 of the refrigerant recovery device 14 (the pressure at the inlet 36 of the refrigerant recovery device 14), and the pressure threshold 120 and duration 122 in the memory unit 102. Here, the detected pressure DPS indicates the pressure of the refrigerant circuit 30 of the air conditioner 12 in normal mode.

When the removal signal is low, the determiner 118 controls the three-way valve 40 so that the first port 41 and the second port 42 of the three-way valve 40 are in communication (normal mode).

When the removal signal changes from Low to High, the determiner 118 determines whether to control the three-way valve 40 to the circulation mode or the vaporization promotion mode based on the result of comparing the detected pressure DPS (pressure of the refrigerant circuit 30) with the pressure threshold 120. Specifically, when the detected pressure DPS is higher than the pressure threshold 120, the determiner 118 estimates that the refrigerant in the refrigerant circuit 30 is unlikely to condense at low temperature, and controls the three-way valve 40 so that the second port 42 and the third port 43 of the three-way valve 40 are in a communication state (circulation mode). On the other hand, when the detected pressure DPS is equal to or lower than the pressure threshold 120, the determiner 118 estimates that the refrigerant in the refrigerant circuit 30 is likely to condense at low temperature, and controls the three-way valve 40 so that the first port 41 and the third port 43 of the three-way valve 40 are in a communication state (vaporization promotion mode).

The determiner 118 controls the three-way valve 40 to switch from the vaporization promotion mode to the circulation mode when the duration 122 has elapsed since the transition to the vaporization promotion mode.

The determiner 118 outputs a three-way valve signal indicating whether the mode is currently normal mode, circulation mode, or enhanced evaporation mode.

1, the retransmission controller 78 receives as input the three-way valve signal, the detected pressure DPR (pressure in the retransmission pipe 58) of the pressure detector 70 on the retransmission pipe 58C, and the detected pressure DPS (pressure at the inlet 36 of the refrigerant recovery device 14) of the pressure detector 37 of the refrigerant recovery device 14. When the three-way valve signal indicates circulation mode, the retransmission controller 78 controls the pressure regulator 72 based on the detected pressures DPR and DPS so that the pressure in the retransmission pipe 58C downstream of the pressure regulator 72 (gas outlet 74 side) is higher than the pressure at the inlet 36 of the refrigerant recovery device 14. This makes it possible to prevent refrigerant from flowing back from the front pipe 52 toward the retransmission pipe 58C. When the three-way valve signal indicates the evaporation promotion mode, the retransmission controller 78 controls the pressure regulator 72 so that the pressure in the retransmission pipe 58C downstream of the pressure regulator 72 (gas outlet 74 side) becomes a predetermined pressure at which gas can be sent into the refrigerant circuit 30 of the air conditioner 12.

FIG. 5 is a block diagram of the pressure controller 97A. The pressure controller 97A includes a pressure acquirer 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 a flash memory. The memory within the pressure controller 97A may be used as the storage unit 102.

The memory unit 102A stores first pressure information 214 and second pressure information 215. The first pressure information 214 represents the pressure difference PA between the inside and outside of the separation membrane 92A, which is set by the first pressure regulator 98A. The second pressure information 215 represents the pressure PB during adsorption of the adsorption unit 315, which is set by the second pressure regulator 98B.

The second pressure regulator 98B adjusts the pressure during adsorption of the adsorption section 315 of the adsorption module 68B. The second pressure regulator 98B is disposed downstream of the adsorption module 68B and includes a second back pressure valve that adjusts the pressure on the primary side of the second pressure regulator 98B.

Before refrigerant recovery, the pressure acquirer 211A acquires the first pressure information 214 from the memory unit 102A and sends it to the first pressure controller 212. The first pressure controller 212 controls the first pressure regulator 98A to set the inside/outside pressure difference P1o of the separation membrane 92A to PA.

Before refrigerant recovery, the pressure acquirer 211A acquires second pressure information 215 from the memory unit 102A and sends it to the second pressure controller 213. The second pressure controller 213 controls the second pressure regulator 98B to set the adsorption pressure of the adsorption unit 315 to PB.

When the adsorption pressure PB of the adsorption section 315 is large, the refrigerant is more easily adsorbed by the adsorbent 350, and the amount of refrigerant adsorbed per unit weight of the adsorbent 350 increases. Therefore, the amount of adsorbent 350 used can be reduced.

The control unit 330 may therefore switch the outflow destination of the switching valve 320 to the first adsorption unit 321 loaded with a small amount of adsorbent 350 when the pressure PB during adsorption of the adsorption unit 315 is equal to or greater than the reference value, and may switch the outflow destination of the switching valve 320 to the second adsorption unit 322 loaded with a large amount of adsorbent 350 when the pressure PB during adsorption of the adsorption unit 315 is less than the reference value.

Next, we will explain the set pressure PA of the pressure difference between the inside and outside of the separation membrane 92A. Figure 6 is a diagram for explaining the set pressure PA of the pressure difference between the inside and outside of the separation membrane 92A.

When a mixed gas containing non-condensable gas 26 flows into the separation membrane 92A at a rate greater than the permeable flow rate, the non-condensable gas 26 may flow not only toward the discharge port 94A, but also toward the outlet 96A. To prevent this, it is necessary to adjust the amount of mixed gas 22 flowing into the separation membrane 92A.

Even if a large amount of non-condensable gas 26 flows through separation membrane 92A, the non-condensable gas 26 passes through outlet 96A and refrigerant recovery device 14 and is returned to recovery cylinder 16. The non-condensable gas 26 then flows again into separation device 18 and undergoes the separation process. By repeatedly flowing non-condensable gas 26 into separation device 18, the amount of non-condensable gas 26 can be reduced.

The set pressure PA of the pressure difference between inside and outside the separation membrane 92A is set to a value less than the first threshold value TH1. This allows the second gas component 25 of the air-conditioning refrigerant and the non-condensable gas 26 to easily permeate the separation membrane 92A, while making it difficult for the first gas component 23 of the air-conditioning refrigerant to permeate the separation membrane 92A.

This section explains how to set the set pressure PA to a more appropriate value that satisfies the above conditions.

As shown in Figure 1, the pressure difference between the inside and outside of the separation membrane 92A is P1o, the pressure inside the separation membrane 92A (i.e., the pressure on the input side of the separation membrane 92A) is P1i, and the pressure on the permeation side of the separation membrane 92A is P1t. If the pressure on the input side of the adsorption module 68B is P2i, the following equation holds.

P1t=P2i...(1)
P1t=P1i-P1o...(2)
In order to prevent the gas from flowing back into the separation membrane 92A, the following conditions must be met.

P1i>P1t=P2i...(3)
By controlling the pressure reducing valve 66 by the delivery controller 76, the pressure P1i can be controlled so as to satisfy the formula (3).

The pressure controller 97A controls the pressure difference P1o between the inside and outside of the separation membrane 92A of the gas separation module 68A by controlling the first pressure regulator 98A so as to satisfy equation (4).

P1o=PA<TH1...(4)
Next, the gas separation module 68A will be described. The mixed gas 22 flows into the gas separation module 68A.

As shown in FIG. 1, the gas separation module 68A includes a cylindrical housing 88A and a cylindrical separation membrane 92A disposed within the housing 88A. The housing 88A includes an inlet 90A for taking in the mixed gas 22, an outlet 96A disposed opposite the inlet 90A for discharging the first gas component 23 of the air-conditioning refrigerant (retransmitted gas refrigerant), and an outlet 94A for discharging the mixed gas 24 consisting of the non-condensable gas 26 and the second gas component 25 of the air-conditioning refrigerant (in this embodiment, "R-32").

The second gas component 25 (R-32) of the air-conditioning refrigerant permeates the separation membrane 92A at about half its capacity. The non-condensable gas 26 easily permeates the separation membrane 92A. Here, the first gas component 23 may be an air-conditioning refrigerant other than R-32 that does not easily permeate the separation membrane 92A, or it may be R-32 that did not permeate the separation membrane 92A, or it may be a mixed gas of R-32 that did not permeate the separation membrane 92A and an air-conditioning refrigerant other than R-32 that does not easily permeate the separation membrane 92A.

The first end of the separation membrane 92A is connected to the inlet 90A of the housing 88A. The second end of the separation membrane 92A is connected to the outlet 96A of the housing 88A. The mixed gas 22 enters the inside of the separation membrane 92A from the inlet 90A and proceeds toward the outlet 96A, during which the non-condensable gas 26 and about half of the second gas component 25 (R-32) of the air-conditioning refrigerant permeate the separation membrane 92A and exit the separation membrane 92A, and are eventually released into the pipe 59 from the outlet 94A of the housing 88A. In addition, the first gas component 23 of the air-conditioning refrigerant (the remaining R-32 and other air-conditioning refrigerants) of the mixed gas 22 that did not permeate the separation membrane 92A is discharged into the re-transmission pipe 58A from the outlet 96A of the housing 88A.

For example, the separation membrane 92A may be a membrane made of an inorganic material (hereinafter referred to as an inorganic separation membrane) or a membrane made of an organic material (hereinafter referred to as an organic separation membrane). Materials for the inorganic separation membrane may be, for example, ceramics, zeolite, etc. The separation membrane 92A is a membrane that can separate gases with small separation diameters, such as non-condensable gases (N2, O2). The molecular diameter of the separation membrane 92A is approximately 3.8 Å. The separation membrane 92A is polar.

FIG. 7 is a schematic diagram showing the principle of molecular sieving of separation membrane 92A made of an inorganic separation membrane. As shown in FIG. 7, an inorganic molecular membrane has fine holes (pores) and basically performs gas separation using the principle of molecular sieving. Air (non-condensable gas 26), water 28, and R-32 (second gas component 25), which has a small molecular diameter compared to the pore diameter of the inorganic molecular membrane, pass through the pores and exit the separation membrane. Since the molecular diameter of R-32 is close to the pore diameter of the inorganic separation membrane, the amount of permeation is smaller than that of air (non-condensable gas 26).

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

The adsorption section 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 downstream of the first adsorption unit 321 and the second adsorption unit 322, and a refrigerant detection sensor 324.

The switching valve 320 switches between sending the mixed gas 24 to the first adsorption unit 321 or to the second adsorption unit 322. The switching valve 320 is controlled by the control unit 330.

The first adsorption unit 321, the second adsorption unit 322, and the third adsorption unit 323 are loaded with a large number of adsorbents. The larger the surface area of the adsorbent, the higher the adsorption performance of the adsorbent. Small adsorbents may flow into the piping. Therefore, it is desirable for the particle size of the adsorbent to be approximately 0.1 to 10 mm. For example, zeolite, activated carbon, silica alumina, activated alumina, and synthetic zeolite can be used as adsorbents.

In this embodiment, zeolite with a pore size of about 3 to 10 Å is used as the adsorbent. For example, cylindrical A-type zeolite with a pore size of 9 Å and a height of 1.5 mm is loaded as the adsorbent into each of the adsorption units 321, 322, and 323. This type of zeolite not only adsorbs R-32, but also desorbs the R-32 adsorbed in the zeolite.

Figure 8 shows details of the first suction unit 321, the second suction unit 322, and the third suction unit 323.

Each of the adsorption units 321, 322, and 323 is loaded with an adsorbent 350. The second gas component 25 (R-32) of the air-conditioning refrigerant can be adsorbed by the adsorbent 350. Furthermore, the second gas component 25 (R-32) adsorbed by the adsorbent 350 can be desorbed from the adsorbent 350.

FIG. 9 shows an example of refrigerant being adsorbed to the adsorbent 350. If the diameter of the pores (holes) of the adsorbent 350 and the diameter of the second gas component 25 of the air-conditioning refrigerant are approximately equal, the second gas component 25 of the air-conditioning refrigerant is likely to be adsorbed into the pores (holes) of the adsorbent 350. In this case, once the second gas component 25 has been adsorbed, it is difficult to escape through the holes, and therefore difficult to desorb.

In the present embodiment, the diameter of the second gas component 25 (R-32) is slightly smaller than the diameter of the pores of the adsorbent 350, so it is easily adsorbed by the pores of the adsorbent 350, and the second gas component 25 (R-32) adsorbed by the pores of the adsorbent 350 begins to desorb when the pressure in each of the adsorption units 321, 322, and 323 is lowered.

The diameter of the non-condensable gas 26 is even smaller than the diameter of the second gas component 25. Therefore, the non-condensable gas 26 is not adsorbed by the adsorbent 350. The diameter of the gas component 29 is larger than the diameter of the pores (holes) of the adsorbent 350, so the gas component 29 is not adsorbed by the adsorbent 350.

Figure 10 shows another example of refrigerant adsorption to the adsorbent 350. Smaller holes and cracks exist within the larger particles of the adsorbent 350. The second gas component 25 of the air-conditioning refrigerant is likely to be adsorbed into such holes and cracks.

When zeolite is used as the adsorbent 350, it is possible to 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 the adsorbent 350. For example, when the air-conditioning refrigerant is R-32, if zeolite is used as the adsorbent 350, R-32 is more easily desorbed than when the above-mentioned activated carbon is used. For this reason, it can be said that zeolite is suitable for adsorbing and desorbing R-32.

Returning to FIG. 1, the amount of adsorbent contained in the second adsorption unit 322 is greater than the amount of adsorbent contained in the first adsorption unit 321, and the second adsorption unit 322 can adsorb more refrigerant than the first adsorption unit 321.

The control unit 330 receives the first threshold pressure TP and the detected pressure DP (pressure inside the recovery cylinder 16) of the pressure detector 61 on the dispatch pipe 56.

When the detected pressure DP is equal to or lower than the first threshold pressure TP, the control unit 330 sets the adsorption unit 315 to be used between the first adsorption unit 321 and the second adsorption unit 322 to 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 the mixed gas 22 in the recovery cylinder 16 is small, and the detected pressure DP is also small, so it can be assumed that the amount of the second gas component 25 of the air-conditioning refrigerant to be adsorbed is also small. The control unit 330 switches the outflow destination of the switching valve 320 to the direction of the first adsorption unit 321.

When the detected pressure DP exceeds the first threshold pressure TP, the control unit 330 sets the adsorption unit 315 to be used between the first adsorption unit 321 and the second adsorption unit 322 to the second adsorption unit 322. 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 cylinder 16 is large, the detected pressure DP also becomes large, and it can be assumed that the amount of the second gas component 25 of the air-conditioning refrigerant to be adsorbed is also large. The control unit 330 switches the outflow destination of the switching valve 320 to the direction of the second adsorption unit 322.

The mixed gas 24 flows into the adsorption section 315 that is being used of 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 of the adsorption section 315 that is being used, and most of the non-condensable gas 26 contained in the mixed gas 24 flows out from the adsorption section 315 that is being used.

The third adsorption unit 323 is disposed after the first adsorption unit 321 and the second adsorption unit 322. When the gas leaking from the adsorption section 315 in use of the first adsorption unit 321 or 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 the gas.

The non-condensable gas 26 contained in the gas that flows out from the adsorption section 315 in use flows out from the third adsorption unit 323. The non-condensable gas 26 is discharged from the discharge port 94B through the pipes 57A and 57B to the atmosphere. In this case, the first port 411 and the second port 412 of the three-way valve 402 are controlled to be in a communicating state.

The refrigerant detection sensor 324 detects whether or not refrigerant is contained in the gas that has flowed out from the adsorption section 315 that is being used among the first adsorption unit 321 and the second adsorption unit 322. The refrigerant detection sensor 324 is configured, for example, by an infrared sensor.

When the refrigerant detection sensor 324 detects a refrigerant, the control unit 330 determines that the adsorption unit 315 in use among the first adsorption unit 321 and the second adsorption unit 322 has been broken (the adsorption unit 315 is in a state where it cannot adsorb the refrigerant), and switches the unused adsorption unit 315 to the adsorption unit 315 in use. The control unit 330 switches the outflow destination of the switching valve 320 to the direction of the newly used adsorption unit 315.

As described above, in this embodiment, R-32 (second gas component 25) can be adsorbed and desorbed onto the adsorbent 350. If the adsorbent 350 is only allowed to adsorb R-32, or if an adsorbent 350 that cannot desorb R-32 is used, the adsorbent 350 must be discarded after a certain amount of R-32 has been adsorbed.

The adsorbent 350 in this embodiment can desorb the adsorbed R-32, so the adsorbent 350 can be used repeatedly. This can reduce the cost of the adsorbent.

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

For example, if the mixed gas 22 is composed 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. The remaining half of the R-32 is then sent to the adsorption module 68B as mixed gas 24 containing the non-condensable gas 26, and the remaining R-32 is adsorbed by the adsorbent 350 of the adsorption module 68B.

The gas separation device 68 can also be configured with only the adsorption module 68B. In this case, the cost of the device can be reduced by not providing the gas separation module 68A. On the other hand, if the gas separation device 68 is configured with the gas separation module 68A and the adsorption module 68B, the amount of adsorbent 350 required in the adsorption module 68B can be reduced by half, since the gas separation module 68A can separate about half of the R-32. In this case, there are advantages in that the adsorption module 68B can be made smaller and the cost of the adsorbent 350 can be reduced.

In this embodiment, when the mixed gas 22 is composed of R-32, other air-conditioning refrigerants, and non-condensable gas 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 from the outlet 96A as the first gas component 23 of the air-conditioning refrigerant. Then, in the adsorption module 68B, only R-32 is adsorbed and desorbed. When the gas separation module 68A is not used, the adsorption module 68B adsorbs and desorbs R-32 and other air-conditioning refrigerants.

Figure 11 is a graph showing the relationship between the degree of vacuum and the adsorption rate of R-32 to zeolite. R-32 (second gas component 25) is physically adsorbed to zeolite (adsorbent 350). The adsorption energy when physically adsorbed to adsorbent 350 is lower than the adsorption energy when chemically adsorbed to adsorbent 350. Therefore, when physically adsorbed to adsorbent 350, desorption is easier than when chemically adsorbed to adsorbent 350. Also, when physically adsorbed, the amount of adsorption increases linearly with increasing pressure (Henry's law).

A specific example is shown below. As shown in FIG. 11, when the pressure inside the adsorption unit is P2 (0 MPa), the adsorption rate (= adsorption amount/saturated adsorption amount) for the adsorbent 350 (zeolite) is 70%. In this case, if the pressure inside the adsorption unit is lowered, the adsorption rate decreases linearly, and when the pressure inside the adsorption unit is P1, the adsorption rate for the adsorbent 350 (zeolite) is 20%.

If the relationship between the degree of vacuum and the adsorption rate of R-32 onto zeolite shown in Figure 11 is rewritten as the relationship between the degree of vacuum and the desorption rate of R-32 onto zeolite (= desorption amount/saturation adsorption amount), it becomes as shown in Figure 12. Figure 12 is a graph showing the relationship between the degree of vacuum and the desorption rate of R-32 onto zeolite.

When the pressure inside the adsorption unit is P2 (0 MPa), the desorption rate is 30% (= 100% - 70%). When the pressure inside the adsorption unit is lowered to P1, the desorption rate reaches 80% (= 100% - 20%). For example, this graph shows that to ensure a desorption rate of 60% or more, the pressure during desorption must be kept below -0.06 MPa.

In this embodiment, in the above-mentioned adsorption process (circulation mode, evaporation promotion mode), the second gas component 25 (R-32) of the air-conditioning refrigerant is adsorbed onto the adsorbent 350 of the adsorption section 315 (first adsorption unit 321, second adsorption unit 322, or third adsorption unit 323). Then, in the desorption process carried out after the adsorption process, the second gas component 25 (R-32) of the air-conditioning refrigerant adsorbed onto the adsorbent 350 is desorbed.

In the desorption process, the control unit 330 closes the control valve 64. Similarly to the circulation mode, the control unit 330 also controls the second port 42 and the third port 43 of the three-way valve 40 to be in communication with each other. Furthermore, the control unit 330 also controls the first port 411 and the third port 413 of the three-way valve 402 to be in communication with each other.

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

As a result, as explained with reference to FIG. 12, the second gas component 25 (R-32) of the air-conditioning refrigerant adsorbed by the adsorbent 350 in each adsorption unit begins to desorb. The desorbed second gas component 25 of the air-conditioning refrigerant is then sucked by the suction pump of the refrigerant recovery device 14 via the pipes 57A, 58B, 58C, and 52, and is compressed, condensed, and liquefied by the refrigerant recovery device 14, and is recovered in the recovery cylinder 16.

In this way, by performing the desorption process after the adsorption process, the second gas component 25 of the air-conditioning refrigerant adsorbed to the adsorbent 350 is desorbed. Therefore, by repeating the adsorption and desorption processes, the adsorbent 350 can be used repeatedly.

Figure 13 is a graph showing the change in the outlet concentration of R-32 during the adsorption and desorption processes. The vertical axis shows the concentration (outlet concentration) of the second gas component 25 (R-32) of the air-conditioning refrigerant at the outlet 94B of the adsorption module 68B, and the horizontal axis shows time.

When the adsorption process is being performed, all of the second gas component 25 (R-32) of the air conditioning refrigerant is adsorbed by the adsorbent 350, so the outlet concentration of R-32 is 0 ppm. When the process is then switched to the desorption process, the inside of each adsorption unit approaches a vacuum state due to suction by the suction pump of the refrigerant recovery device 14, and the R-32 desorbed from the adsorbent 350 flows out from the discharge port 94B of the adsorption module 68B. At this time, the outlet concentration of R-32 reaches a maximum (for example, about 27,000 ppm).

After that, as the amount of R-32 adsorbed in the adsorbent 350 decreases, the concentration of R-32 flowing out from the outlet 94B also decreases, and eventually the outlet concentration of R-32 becomes 0 ppm, and the desorption process ends. If the adsorption and desorption processes are then repeated, the outlet concentration of R-32 will repeat the same changes.

Next, a specific refrigerant recovery method using refrigerant recovery system 10B will be described. Figures 14 and 15 are flowcharts showing a specific refrigerant recovery method using refrigerant recovery system 10B in embodiment 1. In Figures 14 and 15, S100 to S103, S126, and S127 are steps performed by an operator, and the other steps are steps performed automatically by refrigerant recovery system 10B.

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

In S101, the operator turns off the power to the air conditioning unit 12, and then connects the air conditioning unit 12, the refrigerant recovery unit 14, the recovery cylinder 16, and the separation unit 18 to each other as shown in FIG. 1.

In S102, the operator turns on the power supply of the separation device 18. After this, the operator inputs the recovered refrigerant information 110 (see FIG. 2) and the pressure threshold 120 and duration 122 (see FIG. 4) related to the vaporization promotion mode from the input unit 100. When the power supply of 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.

In S103, the operator activates the refrigerant recovery device 14. This starts the recovery of refrigerant from the air conditioning device 12.

S104 to S125 are automatic controls by the refrigerant recovery system 10B. In S104 when the recovery process starts, the reference pressure acquirer 104 of the dispatch controller 76 acquires the saturated vapor pressure of the recovered refrigerant at the detected temperature DT (temperature inside the recovery cylinder 16) of the temperature detector 62 as the reference pressure RP based on the pressure characteristics of the recovered refrigerant indicated by the recovered refrigerant information 110 (see FIG. 3). The determiner 108 of the dispatch controller 76 checks whether the detected pressure DP (pressure inside the recovery cylinder) of the pressure detector 61 is higher than the reference pressure RP. As shown in S104, the determiner 108 may check whether the detected pressure DP (pressure inside the recovery cylinder) is higher than the pressure (RP+α, hereinafter referred to as the reference pressure) obtained by adding a predetermined pressure A to the reference pressure RP.

If the detected pressure DP is equal to or lower than the reference pressure (RP+α) (S104: NO), the determiner 108 determines that it is not necessary to remove the non-condensable gas from the recovery cylinder 16, and continues refrigerant recovery (S105).

On the other hand, if the detected pressure DP is higher than the reference pressure (RP+α) (S104: YES), the determiner 108 determines that the non-condensable gas in the recovery cylinder 16 needs to be removed, changes the removal signal from Low to High, and proceeds to S106. Note that by making a determination using the reference pressure in this manner, it is possible to start removing the non-condensable gas after a certain amount of non-condensable gas has accumulated in the recovery cylinder 16.

In S106, when the adsorption process starts, the three-way valve controller 80 executes the first three-way valve control in response to the removal signal changing from low to high. Figure 16 is a flowchart showing the first three-way valve control.

In S200, the determiner 118 of the three-way valve controller 80 checks whether the detected pressure DPS (pressure of the refrigerant circuit 30) of the pressure detector 37 of the refrigerant recovery device 14 is equal to or lower than the pressure threshold value 120 stored in the memory unit 102. The pressure threshold value 120 is, for example, about 0.1 MPA.

If S200 is NO, the determiner 118 estimates that the refrigerant in the refrigerant circuit 30 of the air conditioner 12 is unlikely to undergo low-temperature condensation, controls the three-way valve 40 to a circulation mode in which the second port 42 and the third port 43 are connected (S206), turns off the evaporation promotion flag (S208), and ends the first three-way valve control.

On the other hand, if S200 is YES, the determiner 118 estimates that there is a high possibility that the refrigerant in the refrigerant circuit 30 of the air conditioner 12 will condense at a low temperature, controls the three-way valve 40 to an evaporation promotion mode in which the first port 41 and the third port 43 are connected (S202), turns on the evaporation promotion flag (S204), and ends the first three-way valve control.

Referring again to FIG. 14. When the detected pressure DP is equal to or lower than the first threshold pressure TP (S107: YES), the control unit 330 sets the suction unit 315 to be used to the first suction unit 321, and switches the outflow destination of the switching valve 320 to the direction of the first suction unit 321.

If the detected pressure DP exceeds the first threshold pressure TP (S107: NO), the control unit 330 sets the suction unit 315 to be used to the second suction unit 322, and switches the outflow destination of the switching valve 320 to the direction of the second suction unit 322.

In S110, the pressure controller 97A starts adjusting the internal/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.

In S111, the determiner 108 of the delivery controller 76 opens the control valve 64 on the delivery pipe 56. Note that the timing of changing the removal signal from Low to High, the execution of S106 (first three-way valve control), and the execution of S111 (operation of opening the control valve 64) are almost simultaneous. Also, 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 cylinder 16 is sent to the gas separation device 68.

In the circulation mode, a circulation loop is formed consisting of the separation device 18, the refrigerant recovery device 14, and the recovery cylinder 16, and the mixed gas 22 in the recovery cylinder 16 is repeatedly sent to the gas separation device 68. The non-condensable gas is released to the atmosphere. The re-sent gas refrigerant is sent to the front pipe 52 in front of the refrigerant recovery device 14, passes through the refrigerant recovery device 14, and returns to the recovery cylinder 16 in a liquefied state. As a result, the non-condensable gas in the recovery cylinder 16 is gradually removed, and the pressure in the recovery cylinder 16 decreases.

In the evaporation promotion mode, the re-transmitted gas refrigerant, which is part of the mixed gas 22 in the recovery cylinder 16, is sent into the refrigerant circuit 30 of the air conditioner 12, raising the temperature of the refrigerant in the refrigerant circuit 30. This promotes evaporation of the refrigerant, and when refrigerant recovery is resumed, the refrigerant recovery speed can be improved.

The re-transmission controller 78 controls the pressure regulator 72 in the circulation mode and the vaporization promotion mode to adjust the pressure in the re-transmission pipe 58A downstream of the pressure regulator 72 (the gas outlet 74 side).

In S112, the determiner 108 of the delivery controller 76 checks whether the detected pressure DP of the pressure detector 61 (pressure inside the recovery cylinder 16) is equal to or lower than the reference pressure RP. If S112 is NO, the removal of non-condensable gas continues (S113) and proceeds to S114.

If the refrigerant detection sensor 324 detects a refrigerant (S114: YES), the control unit 330 switches the outflow destination of the switching valve 320.

In S116, the three-way valve controller 80 executes second three-way valve control. FIG. 17 is a flowchart showing the second three-way valve control.

In S300, the determiner 118 of the three-way valve controller 80 checks whether the evaporation promotion flag is on. If S300 is NO (circulation mode), the second three-way valve control ends. On the other hand, if S300 is YES (evaporation promotion mode), the process proceeds to S302.

In S302, the determiner 118 checks whether the duration 122 (see FIG. 4) stored in the memory unit 102 has elapsed since the transition to the vaporization promotion mode. If S302 is NO, the determiner 118 determines that the vaporization promotion mode needs to be continued, and ends the second three-way valve control. On the other hand, if S302 is YES, the determiner 118 determines that the vaporization promotion mode may be ended, controls the three-way valve 40 to a circulation mode in which the second port 42 and the third port 43 are connected (S304), turns off the vaporization promotion flag (S306), and ends the second three-way valve control.

Referring again to FIG. 14. In S112, if the detected pressure DP (pressure inside the recovery cylinder 16) of the pressure detector 61 becomes equal to or lower than the reference pressure RP (S112: YES), the determiner 108 of the dispatch controller 76 determines that the removal of the non-condensable gas inside the recovery cylinder 16 has been completed, and proceeds to S117.

In S117, the determiner 108 of the dispatch controller 76 closes the control valve 64 on the dispatch pipe 56 and changes the removal signal from High to Low. In response to the change in the removal signal from High to Low, the determiner 118 of 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 in communication. The pressure reducing valve controller 106 of the dispatch controller 76 ends control of the pressure reducing valve 66, and the retransmission controller 78 ends control of the pressure regulator 72.

In S118, the pressure controller 97 ends the adjustment of the inside/outside 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.

In S119 shown in FIG. 15, the refrigerant recovery device 14 checks whether the detected pressure DPS (pressure of the refrigerant circuit 30) of the pressure detector 37 has become negative. If S119 is NO, the refrigerant recovery device 14 continues refrigerant recovery (S120), and if S119 is YES, the refrigerant recovery device 14 notifies the operator that refrigerant recovery has ended by using a lamp or sound, etc.

The desorption process begins at S121. In S121, the control unit 330 estimates the amount of adsorption of the second gas component 25 (R-32) of the air-conditioning refrigerant adsorbed by the adsorbent 350 of the adsorption unit 315 in the adsorption process, and calculates the pressure in the adsorption unit to be controlled in the desorption process and the time required for the desorption process (referred to as the "predetermined time") from the estimated amount of adsorption.

In S122, the control unit 330 closes the control valve 64 and transitions the three-way valves 40, 402 to the attachment/detachment 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 communication with each other, and controls the first port 411 and the third port 413 of the three-way valve 402 to be in communication with each other.

In S123, the control unit 330 drives the suction pump of the refrigerant recovery device 14. This causes the second gas component 25 (R-32) of the desorbed air-conditioning refrigerant to be recovered in the recovery cylinder 16. The control unit 330 continues desorption (S125) until a predetermined time (the time calculated in S121) has elapsed (S124: YES).

When the desorption process is completed, in S126, the operator stops the refrigerant recovery device 14. In S127, the operator turns off the power to the separation device 18.

Next, the effects of the refrigerant recovery system 10B described above will be explained. The refrigerant recovery system 10B is a system that recovers air-conditioning refrigerant from the refrigerant circuit 30 of the air-conditioning device 12 as a refrigeration and air-conditioning device. The refrigerant recovery system 10B includes a recovery cylinder 16 as a first recovery device, a separation device (adsorption device) 18, and a desorption device 19. The recovery cylinder 16 recovers the compressed and 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 gas component of the air-conditioning refrigerant (the second gas component of the air-conditioning refrigerant 25) of the mixed gas 22 consisting of the gas component of the air-conditioning refrigerant (the first gas component of the air-conditioning refrigerant 23, the second gas component of the air-conditioning refrigerant 25) and the non-condensable gas 26 contained inside the recovery cylinder 16 that recovered the compressed and condensed refrigerant. The desorption device 19 desorbs the gas component of the air-conditioning refrigerant (the second gas component of the air-conditioning refrigerant 25) adsorbed by the adsorbent 350, and stores the desorbed gas component of the air-conditioning refrigerant (the second gas component of the air-conditioning refrigerant 25).

In this way, by operating the adsorption device 18, the mixed gas 22 containing the non-condensable gas 26 inside the recovery cylinder 16 can be extracted and the second gas component 25 of the air-conditioning refrigerant from the mixed gas 22 can be adsorbed onto the adsorbent 350, and by operating the desorption device 19, the second gas component 25 of the air-conditioning refrigerant can be desorbed from the adsorbent 350 and recovered, so that the adsorbent 350 can be reused repeatedly. This allows the gas contained in the recovery cylinder 16 to be suitably separated into the non-condensable gas 26 and the gas component of the air-conditioning refrigerant while reducing the non-condensable gas 26 in the recovery cylinder 16.

The adsorption module 68B includes an outlet 94B that releases the non-condensable gas 26 from the mixed gas 24 that has not been adsorbed by the adsorbent 350 to the atmosphere. This allows only the non-condensable gas 26 accumulated in the recovery cylinder 16 to be released to the atmosphere without mixing with the gas components of the air-conditioning refrigerant.

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 gas component 23 of the air-conditioning refrigerant and a mixed gas 24 (second mixed gas) consisting of a second gas component 25 of the air-conditioning refrigerant and a non-condensable gas 26. The adsorbent 350 of the adsorption module 68B adsorbs the second gas 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 cylinder 16. The refrigerant recovery device 14 generates compressed condensed refrigerant by compressing and condensing the air-conditioning refrigerant. The recovery cylinder 16 recovers the compressed condensed refrigerant generated by the refrigerant recovery device 14. The refrigerant recovery system 10B includes a re-transmission pipe 58A as a first re-transmission pipe, a re-transmission pipe 58B as a second re-transmission pipe, and a re-transmission pipe 58C as a third re-transmission pipe. The re-transmission pipe 58A receives the first gas component 23 of the air-conditioning refrigerant separated by the gas separation module 68A. The re-transmission pipe 58B receives the second gas component 25 of the air-conditioning refrigerant desorbed from the adsorbent 350. The re-transmission pipe 58C mixes the first gas component 23 and the second gas component 25 and re-transmits them between the refrigerant circuit 30 and the refrigerant recovery device 14.

In this way, before the gas components of the air-conditioning refrigerant are adsorbed by the adsorbent 350 of the adsorption module 68B, some of the gas components of the air-conditioning refrigerant can be removed by the gas separation module 68A, so that the amount of adsorbent 350 that needs to be prepared can be reduced and the adsorption module 68B can be made smaller. In addition, the gas components of the air-conditioning refrigerant desorbed from the adsorbent 350 are compressed and condensed through the refrigerant recovery device 14 and recovered in the recovery cylinder 16 after liquefaction, so that the volume of the recovery cylinder 16 can be reduced and there is no need to prepare multiple recovery cylinders.

The adsorbent 350 is a zeolite adsorbent. By using a zeolite adsorbent as the adsorbent 350, the second gas component 25 of the air conditioning refrigerant can be adsorbed and desorbed effectively.

The gas component of the air conditioning refrigerant (second gas component 25 of the air conditioning refrigerant) is R-32. This allows R-32 to be adsorbed and desorbed effectively.

Other effects are described below. According to the refrigerant recovery system 10B, the mixed gas 22 inside the recovery cylinder 16 is sent to the gas separation device 68, whereby non-condensable gases are separated from the mixed gas 22 and discharged to the atmosphere, and the re-sent gas refrigerant, which has a reduced amount of non-condensable gas compared to the mixed gas 22, is discharged from the gas separation device 68 and sent into the piping between the refrigerant circuit 30 of the air conditioning device 12 and the refrigerant recovery device 14. The re-sent gas refrigerant passes through the refrigerant recovery device 14 again and returns to the recovery cylinder 16 in a liquefied state.

In this way, the non-condensable gas in the recovery cylinder 16 can be reduced while maintaining the connection between the recovery cylinder 16, the refrigerant recovery device 14, and the air conditioning device 12. The internal pressure rise of the recovery cylinder 16 can be suppressed, the refrigerant recovery speed to the recovery cylinder 16 can be improved, and the refrigerant charge amount of the recovery cylinder 16 can be increased. Since the retransmitted gas refrigerant is liquefied (in a reduced volume state) and returns to the recovery cylinder 16, the refrigerant charge amount of the recovery cylinder 16 can be further increased. It is significant that the recovery cylinder 16, the gas separation device 68, and the refrigerant recovery device 14 are arranged in this order in order to send the mixed gas 22 in the recovery cylinder 16 to the gas separation device 68.

Furthermore, most of the air conditioning refrigerant separated by the gas separation device 68 is re-sent between the refrigerant circuit 30 and the refrigerant recovery device 14. The three-way valve 40 can be used to switch whether this separated air conditioning refrigerant is sent to the refrigerant circuit 30 or to the refrigerant recovery device 14. In the evaporation promotion mode, the air conditioning refrigerant separated by the gas separation device 68 is sent to the refrigerant circuit 30, thereby raising the temperature of the refrigerant in the refrigerant circuit 30. This promotes evaporation of the refrigerant, and when refrigerant recovery is resumed, the refrigerant recovery speed can be improved. In the circulation mode, the air conditioning refrigerant separated by the gas separation device 68 is sent to the refrigerant recovery device 14, and the recovery process of the air conditioning refrigerant separated by the gas separation device 68 is executed again.

The gas separation device 68 is attached to the top of the recovery cylinder 16. Therefore, liquid components such as liquid refrigerant and mixed water remain at the bottom of the recovery cylinder 16, and liquid refrigerant and a large amount of water do not mix with the separation membrane 92A and adsorbent 350 of the gas separation device 68, and the gas separation effect of the separation membrane 92A and adsorbent 350 can be suppressed from decreasing. The air conditioning refrigerant is adiabatically compressed and liquefied in the refrigerant recovery device 14 and filled into the recovery cylinder 16. Therefore, only the refrigerant equivalent to the saturated vapor pressure is vaporized in the volume of the space in the recovery cylinder 16, and most of the refrigerant is liquefied in the recovery cylinder 16. Since the proportion of vaporized refrigerant (gas refrigerant) is low, the amount of gas refrigerant sent to the gas separation device 68 can be reduced, and the risk of refrigerant leakage in the gas separation device 68 can also be reduced.

A circulation loop is formed between the separation device 18, the refrigerant recovery device 14, and the recovery cylinder 16, and the gas separation device 68 repeatedly separates non-condensable gases, effectively removing the non-condensable gases from within the recovery cylinder 16.

The control valve 64 is opened and the gas separation device 68 removes the non-condensable gas only when non-condensable gas is present in the recovery cylinder 16, so that unnecessary use of the gas separation device 68 can be avoided when there is little or no non-condensable gas in the recovery cylinder 16.

The pressure characteristics 112 of multiple types of refrigerants are stored in the memory unit 102 of the separation device 18, so a common separation device 18 can be used to recover different types of refrigerants.

When the gas separation device 68 is used (when the control valve 64 is open) and the pressure in the refrigerant circuit 30 is higher than a predetermined pressure, the re-sent gas refrigerant can be accurately sent from the re-sent pipe 58A to the refrigerant recovery device 14. Also, when the gas separation device 68 is used (when the control valve 64 is open) and the pressure in the refrigerant circuit 30 is equal to or lower than a predetermined pressure, the re-sent gas refrigerant (having a higher temperature than the refrigerant circuit 30), which is a part of the gas refrigerant in the recovery cylinder 16 containing the refrigerant that has been adiabatically compressed in the refrigerant recovery device 14 and has a higher temperature than when it flowed into the refrigerant recovery device 14, can be sent to the refrigerant circuit 30. This increases the temperature of the refrigerant in the refrigerant circuit 30, promoting the gasification of the refrigerant, and improving the refrigerant recovery speed when refrigerant recovery is resumed.

Furthermore, when the air conditioning refrigerant contains R-32, it is not possible to separate the non-condensable gas 26 from the refrigerant gases 23 and 25 using a single gas separation module. In this embodiment, by using two gas separation modules, only the non-condensable gas 26 can be released into the atmosphere.

In this embodiment, the adsorption module 68B has an adsorption section 315 including an adsorbent 350 that easily adsorbs the second gas component 25 of the air-conditioning refrigerant. By using the adsorbent 350, it is possible to separate the mixed gas 24 that could not be separated by the separation membrane 92A of the gas separation module 68A. In addition, by using an adsorbent as the adsorption module 68B instead of a separation membrane different from the separation membrane 92A of the gas separation module 68A, it becomes easier to discard and recover the gas that is not released into the atmosphere.

In this embodiment, a first adsorption unit 321 and a second adsorption unit 322 are provided, each loaded with a different amount of adsorbent, and by using an adsorption unit according to the amount of adsorption, it is possible to recover and discard only the adsorbent that has broken through. In particular, the adsorbent that has adsorbed R-32 is irreversible and must be discarded and replaced, making this a particularly effective method.

Furthermore, according to this embodiment, even if the first adsorption unit 321 or the second adsorption unit 322, which are the main adsorption units, should breakthrough, the existence of the third adsorption unit 323 prevents refrigerant from remaining in the gas released to the atmosphere and leaking into the atmosphere.

Furthermore, any or all of the first adsorption unit 321 to the third adsorption unit 323 may be made detachable. By making the adsorption units detachable, the adsorbent can be quickly collected, disposed of, and replaced after the adsorption unit breaks through the adsorption capacity.

By locating the refrigerant detection sensor 324 after the first adsorption unit 321 and the second adsorption unit 322, even if the adsorption unit being used breaks through adsorption, the refrigerant detection sensor 324 can detect the refrigerant and quickly switch the adsorption unit being used. In addition, because the third adsorption unit 323 exists after the refrigerant detection sensor 324, even if the refrigerant detection sensor 324 detects refrigerant, the refrigerant is adsorbed by the third adsorption unit 323, and no refrigerant remains in the gas released to the atmosphere.

Embodiment 2.
18 is a schematic diagram of a refrigerant recovery system 10 according to embodiment 2. The refrigerant recovery system 10B according to embodiment 1 is configured to include a gas separation module 68A and an adsorption module 68B as an adsorption device (separation device) 18, and to include a refrigerant recovery device 14 and a recovery cylinder 16 as a desorption device 19.

In contrast, the refrigerant recovery system 10 according to the second embodiment is configured to include an adsorption module 468 as the adsorption device (separation device) 418, and a pump 440 as a suction device, a recovery cylinder 470 as a second recovery device, and piping 58A as the 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 cylinder 470.

The recovery process of the second embodiment is essentially the same as that of the first embodiment. In the recovery process, the condensed refrigerant is recovered using the air conditioner 12, the refrigerant recovery device 14, and the recovery cylinder 16. However, the refrigerant recovery system 10 does not include a three-way valve 40, and does not have a gas component circulation function as in the first embodiment.

The suction module 468 of the suction device 418 includes an suction section 415. Like the suction section 315, the suction section 415 includes one suction unit (see FIG. 8) similar to the first suction unit 321, the second suction unit 322, or the third suction unit 323.

The adsorption module 468 may include one adsorption unit, or may include an adsorption module 68B that is provided with three adsorption units as in embodiment 1. However, in embodiment 2, the gas separation module 68A is not included.

In the second embodiment as well, the mixed gas 22 consisting of the gas component of the air-conditioning refrigerant and non-condensable gas contained inside the recovery cylinder 16 from which the compressed condensed refrigerant has been recovered is separated in the adsorption module 468. The gas component of the air-conditioning refrigerant assumed in the second embodiment is R-32, and the adsorbent 350 is a zeolite adsorbent. As explained in the first embodiment, the zeolite adsorbent is an adsorbent suitable for reversibly adsorbing and desorbing R-32.

The gas component of the air conditioning refrigerant may be an air conditioning refrigerant other than R-32, or may contain R-32 and one or more types of air conditioning refrigerant other than R-32. The adsorbent 350 may be an adsorbent other than the zeolite adsorbent described in the first embodiment, and may be any adsorbent capable of adsorbing and desorbing the air conditioning refrigerant. However, an adsorbent 350 that irreversibly adsorbs the air conditioning refrigerant (cannot be desorbed) cannot be used. When such an adsorbent is used, if a certain amount or more of the air conditioning refrigerant is adsorbed on the adsorbent, the adsorbent must be replaced, resulting in high running costs.

The mixed gas 22 taken in from the gas inlet 60 flows through the delivery pipe 56. The mixed gas 22 is a gas composed of the gas 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 sent to the adsorption module 468.

The adsorption module 468 includes an adsorption section 415, an inlet 490, a discharge port 494, and an outlet 496. The gas component 423 (R-32) of the air-conditioning refrigerant is adsorbed by the adsorbent 350 (zeolite adsorbent) of the adsorption section 415. In the adsorption process, the non-condensable gas 26 is discharged to the atmosphere from a pipe 424 connected to the discharge port 494. In the desorption process, the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350 is desorbed and collected in the collection cylinder 470 from the outlet 496 via the pipe 58A.

The adsorption device (separation device) 418 further includes a pressure detector 61, a temperature detector 62, a control valve (inlet valve) 64, and a pressure reducing valve 66, which are arranged in the delivery pipe 56. These functions are the same as those in the first embodiment, and are controlled by the control unit 430.

In the recovery process, the control unit 430 determines whether or not it is necessary to remove non-condensable gas from inside the recovery cylinder 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 it is necessary to remove non-condensable gas, the process moves from the recovery process to the adsorption process.

The control unit 430 receives various conditions detected by the adsorption module 468 as a signal DS. The control unit 430 transmits 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 gas, it transmits a signal CB1 that controls the control valve 64 to an open state, and when it determines that it is not necessary to remove non-condensable gas, it transmits a signal CB1 that controls the control valve 64 to a closed state.

Specifically, if it is determined that the detected pressure DP in the recovery cylinder 16 is higher than the reference pressure RP (the saturated vapor pressure of the recovered refrigerant corresponding to the detected temperature DT in the recovery cylinder 16 (see FIG. 3)) (DP>RP), it is determined that removal is necessary. This is the same as the determination in S104 in the first embodiment. Note that, similar to S104, it may also be determined that removal is necessary if DP>RP+α.

The control unit 430 controls the open/close state of each valve by sending a signal CB2 to the control valve 461, a signal CB3 to the detachment valve 462, and a signal CB4 to the exhaust valve 463. The control unit 430 also controls the operation of the pump 440 by sending a signal CP1 to the pump 440. By operating the pump 440, the pressure inside the adsorption unit 415 can be reduced to a predetermined pressure.

When transitioning from the recovery process to the adsorption process, the control unit 430 controls the inlet valve 64 to an open state by signal CB1, the control valve 461 to a signal CB2, and the exhaust valve 463 to a closed state by signal CB4, and controls the desorption valve 462 to a closed state by signal CB3. As a result, the mixed gas 22 in the recovery cylinder 16 flows into the adsorption unit 415. Then, of the mixed gas 22, the gas component 423 (R-32) of the air conditioning refrigerant is adsorbed by the adsorbent 350 in the adsorption unit 415, and the non-condensable gas 26 that is not adsorbed by the adsorbent 350 is released from the pipe 424 to the atmosphere via the release port 494.

When the detected pressure DP becomes equal to or lower than the reference pressure RP (saturated vapor pressure), the control unit 430 ends the adsorption process and transitions to the desorption process. This is the same as the determination in S112 in the first embodiment.

During the desorption process, the control unit 430 controls the inlet valve 64 to a closed state using signal CB1, the exhaust valve 463 to a closed state using signal CB4, and the desorption valve 462 to an open state using signal CB3. The control unit 430 then drives the pump 440 using signal CP1.

By driving the pump 440, the gas in the adsorption section 415 is sucked in, and the pressure in the adsorption section 415 drops. As a result, the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350 starts to desorb. The gas component 423 of the air-conditioning refrigerant is then sucked in by the pump 440, and the gas component 423 of the air-conditioning refrigerant is recovered in the recovery cylinder 470 via the pipe 58A.

The concentration of the gas component 423 (R-32) of the air-conditioning refrigerant at the outlet 494 during the adsorption process and the concentration of the gas component 423 (R-32) of the air-conditioning refrigerant at the outlet 496 during the desorption process transition as shown in Figure 13.

Next, a specific refrigerant recovery method using the refrigerant recovery system 10 will be described. Figure 19 is a flowchart showing a specific refrigerant recovery method using the refrigerant recovery system 10 in embodiment 2.

In S400, the worker stops the air conditioning unit 12. In S401, the worker connects the refrigerant recovery unit 14 and the recovery cylinder 16 to the air conditioning unit 12. In S402, the worker connects the adsorption unit 418 to the recovery cylinder 16, and further connects the desorption unit 419 to the adsorption unit 418.

Below, steps S404 to S407 show the processing of the recovery process. In step S404, the control unit 430 drives the refrigerant recovery device 14 to start refrigerant recovery. This step may be performed by an operator.

In S405, the control unit 430 determines whether the detected pressure DP is greater than the reference pressure RP. In S406, the control unit 430 determines whether refrigerant remains in the refrigerant circuit 30.

If DP>RP (S405: YES), the control unit 430 ends the recovery process and proceeds to S408. If DP≦RP (S405: NO) and the control unit 430 determines that refrigerant remains in the refrigerant circuit 30 (S406: YES), the control unit 430 continues refrigerant recovery (S407) and returns the process to S405. In other words, the control unit 430 continues refrigerant recovery as long as 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), the control unit 430 proceeds to S417.

Below, S408 to S412 show the processing of the adsorption process. In S408, the control unit 430 operates 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 an open state and controlling the desorption valve 462 to a closed state. Note that if the control valve 461 is closed in the recovery process, the control valve 461 is controlled to an open state.

The control unit 430 continues suction (S410) while it determines that DP>RP (S409: NO). If the control unit 430 determines that DP≦RP (S409: YES), it stops the suction device 418 (S411).

If the control unit 430 determines that the recovery of refrigerant from the refrigerant circuit 30 has been completed (S412: YES), the process proceeds to S413. This causes the process to move to the desorption process. On the other hand, if the control unit 430 determines that the recovery of refrigerant from the refrigerant circuit 30 has not been completed (S412: NO), the process returns to S406. This causes the process to return to the recovery process again.

Below, S413 to S416 show the processing of 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 a closed state, controls the desorption valve 462 to an open state, and drives the pump 440 to start the desorption process.

The control unit 430 continues detachment (S415) until a predetermined time (detachment time) required for the detachment process has elapsed (while S414: NO). When the predetermined time (detachment time) has elapsed (S414: YES), the control unit 430 ends the detachment process (S416). The predetermined time (detachment time) is calculated using the same method as S121.

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

As shown in FIG. 19 above, the recovery process, adsorption process, and desorption process are not limited to being performed as a series of processes, and the adsorption process and desorption process may each be performed as independent processes. Other examples of the adsorption process and desorption process are shown in FIG. 20 and FIG. 21 below.

FIG. 20 is a flowchart showing the processing procedure for the adsorption process. This process is basically the same as the adsorption process in FIG. 19.

After the recovery process is performed, if the control unit 430 determines that the detected pressure DP is greater than the reference pressure RP (S600), the adsorption process begins.

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 the desorption valve 462 to be closed. If the control valve 461 is closed in the recovery process, the control valve 461 is controlled to be open.

The control unit 430 monitors (S602) the temperature and pressure of the recovery cylinder 16 (the detected temperature DT of the temperature detector 62, and the detected pressure DP of the pressure detector 61), and estimates the amount of recovered refrigerant (the amount of R-32 to be recovered) from these values (S603). For example, in the example shown in FIG. 3, at the detected temperature DT, the saturated vapor pressure of the recovered refrigerant (R-32) is the reference pressure RP. And, the detected pressure DP - the reference pressure RP is the partial pressure of the non-condensable gas 26. From these pressure ratios, the control unit 430 calculates the amount of substance of the recovered refrigerant (R-32) in the recovery cylinder 16 as the "amount of recovered refrigerant".

In S604, the control unit 430 determines whether the current adsorption amount is less than or equal to the possible adsorption amount. Here, the current adsorption amount is the amount of R-32 already adsorbed by the adsorbent 350 filled in the adsorption unit 415. The possible adsorption amount is the amount of R-32 that can be adsorbed by the adsorbent 350 filled in the adsorption unit 415. The possible adsorption amount can be calculated from the relationship between the detected temperature DT and detected pressure DP and the adsorption rate of R-32 as shown in FIG. 11. In addition, the current adsorption amount can be calculated using the recovered refrigerant amount calculated above. For example, if the current adsorption amount = X1 and the calculated recovered refrigerant amount = X2, then the current adsorption amount after the adsorption process is completed = X1 + X2.

If the control unit 430 determines that the current adsorption amount is greater than the possible adsorption amount (S604: NO), it ends the operation of the adsorption process. In other words, if it determines that the adsorbent 350 cannot adsorb any more R-32, it ends the adsorption process. In this case, the operator must carry out the desorption process.

In S605, the control unit 430 judges whether DP≦RP. This judgment is the same as the judgment in S409. If the control unit 430 judges in S604 that the current adsorption amount≦possible adsorption amount (S604: YES) and that DP>RP (S605: NO), it continues adsorption (S606) and returns to the processing of S604. In other words, adsorption continues as long as the current adsorption amount≦possible adsorption amount and DP>RP. On the other hand, if the control unit 430 judges in S605 that DP≦RP (S605: YES), it ends the adsorption process.

FIG. 21 is a flow chart showing the processing procedure for the desorption process. This process is basically the same as the adsorption process in FIG. 19.

After the control unit 430 has completed the refrigerant recovery in the recovery process (S701), it calculates the pressure in the adsorption unit 415 to be controlled in the desorption process and the desorption time required for the desorption process (also referred to as the "predetermined time", which is the same as the predetermined time in S414) from the amount of R-32 adsorbed by the adsorbent 350 in the adsorption unit 415 (S702), and then starts the operation of the desorption process.

As shown in Figure 12, the amount of R-32 desorbed in the desorption process can be calculated from the difference between the pressure inside the adsorption section 415 at the end of the adsorption process (at the start of the desorption process) and the pressure inside the adsorption section 415 that is finally controlled in the desorption process. In the desorption process, the concentration of R-32 at the outlet 496 of the adsorption section 415 transitions as shown in Figure 13. The desorption time (predetermined time) in Figure 13 is the time required for the concentration of R-32 at the outlet 496 of the adsorption section 415 to reach 0, and the desorption time may be estimated based on an actual measurement value.

When the adsorption process starts, in 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 in a closed state, and the desorption valve 462 to be in an open state. This step may be performed by an operator.

In S704, the control unit 430 drives the pump 440. This starts desorption of the R-32 adsorbed by the adsorbent 350 in the adsorption unit 415. The control unit 430 continues desorption until a predetermined time (desorption time) has elapsed (while S705: NO). 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: YES), the control unit 430 ends the operation of the desorption process (stops the pump 440).

Next, the effects of the refrigerant recovery system 10 described above will be described. The refrigerant recovery system 10 is a system that recovers air-conditioning refrigerant from the refrigerant circuit 30 of the air-conditioning device 12 as a refrigeration and air-conditioning device. The refrigerant recovery system 10 includes a recovery cylinder 16 as a first recovery device, an adsorption device 418, and a desorption device 419. The recovery cylinder 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 that adsorbs the gas component 423 of the air-conditioning refrigerant out of the mixed gas 22 consisting of the gas component 423 of the air-conditioning refrigerant and the non-condensable gas 26 contained inside the recovery cylinder 16 that recovered the compressed and condensed refrigerant. The desorption device 419 desorbs the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350 and accumulates the desorbed gas component 423 of the air-conditioning refrigerant.

In this way, by operating the adsorption device 418, the mixed gas 22 containing the non-condensable gas 26 inside the recovery cylinder 16 can be extracted and the gas component 423 of the air-conditioning refrigerant from the mixed gas 22 can be adsorbed onto the adsorbent 350, and by operating the desorption device 419, the gas component 423 of the air-conditioning refrigerant can be desorbed from the adsorbent 350 and recovered, so that the adsorbent 350 can be reused repeatedly. This allows the gas contained in the recovery cylinder 16 to be suitably separated into the non-condensable gas 26 and the gas component of the air-conditioning refrigerant while reducing the non-condensable gas 26 in the recovery cylinder 16.

The adsorption module 468 includes an outlet 494 that releases the non-condensable gas 26 from the mixed gas 22 that has not been adsorbed by the adsorbent 350 to the atmosphere. This allows only the non-condensable gas 26 accumulated in the recovery cylinder 16 to be released to the atmosphere without mixing with the gas components of the air-conditioning refrigerant.

The desorption device 419 includes a recovery cylinder 470 as a second recovery device, a pipe 58A, and a pump 440 as a suction device. The recovery cylinder 470 accumulates the desorbed gas component 423 of the air-conditioning refrigerant. One end of the pipe 58A is connected to the adsorption module 468, and the other end is connected to the recovery cylinder 470. The pump 440 sucks up the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350 and sends it to the recovery cylinder 470. In this way, the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350 can be desorbed and recovered in the recovery cylinder 470 regardless of the refrigerant recovery status.

The adsorbent 350 is a zeolite adsorbent. By using a zeolite adsorbent as the adsorbent 350, the gas component 423 of the air conditioning refrigerant can be adsorbed and desorbed effectively.

The gas component 423 of the air conditioning refrigerant is R-32. This allows R-32 to be adsorbed and desorbed effectively.

This device is configured to include an adsorption module 468 as the adsorption device 418, and a pump 440 as the suction device, a recovery cylinder 470 as the second recovery device, and piping 58A as the desorption device 419. In other words, it does not include a gas separation module 68A, and this configuration makes it possible for this device to separate R-32 in a compact and simple manner.

Embodiment 3.
22 is a schematic diagram of a refrigerant recovery system 10A according to embodiment 3. The refrigerant recovery system 10 according to embodiment 2 is configured to include an adsorption module 468 as the adsorption device 418, and a pump 440 and a recovery cylinder 470 as the desorption device 419.

In contrast, in the refrigerant recovery system 10A according to the third embodiment, the refrigerant recovery device 14 and the recovery cylinder 16 are configured as a desorption device 419. In the desorption process, the refrigerant recovery device 14 also operates as a suction device, and the recovery cylinder 16 also operates as a second recovery device.

The refrigerant recovery device 14 and the recovery cylinder 16 are configured as a desorption device 419, which is similar to the first embodiment. However, unlike the first embodiment, the third embodiment does not include a gas separation module 68A.

In the third embodiment, as in the first embodiment, the desorption device 419 includes a refrigerant recovery device 14 and a recovery cylinder 16. The gas component 423 of the air-conditioning refrigerant sucked by the pump of the refrigerant recovery device 14 is liquefied and recovered in the recovery cylinder 16 as compressed condensed refrigerant.

Different from the second embodiment, the three-way valve 40 is disposed 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 the pipe 58A. The pipe 58A is connected to the adsorption module 468.

The control unit 430 receives various conditions detected by the adsorption module 468 as a signal DS. The control unit 430 sends a signal CB1 to the inlet valve 64 and a signal CB4 to the exhaust valve 463 to control the open/close state of each valve. The control unit 430 controls the refrigerant recovery device 14 (pump) by sending a signal CP2 to the refrigerant recovery device 14. The control unit 430 switches the mode of the three-way valve 40 by sending a signal CL to the three-way valve 40.

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

As a result, the mixed gas 22 from the recovery cylinder 16 flows into the adsorption section 415. Then, of the mixed gas 22, the gas component 423 of the air-conditioning refrigerant is adsorbed by the adsorbent 350 in the adsorption section 415, and the non-condensable gas 26 that is not adsorbed is released into the atmosphere through the pipe 424.

In a desorption mode for desorbing the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350, the control unit 430 controls the inlet valve 64 to close using a signal CB1, controls the exhaust valve 463 to close using a signal CB4, and controls the three-way valve 40 to bring the second port 42 and the third port 43 into communication (circulation mode) using a signal CL. The control unit 430 then drives the pump of the refrigerant recovery device 14 using a signal CP2.

As a result, the pressure in the adsorption section 415 decreases, and the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350 is desorbed. The gas component 423 of the air-conditioning refrigerant is then liquefied and collected in the recovery cylinder 16 as compressed condensed refrigerant by driving the pump of the refrigerant recovery device 14.

The gas component of the air-conditioning refrigerant assumed in the third embodiment is also R-32, and the adsorbent 350 is a zeolite adsorbent. However, the gas component of the air-conditioning refrigerant may be an air-conditioning refrigerant other than R-32, or may contain R-32 and one or more types of air-conditioning refrigerant other than R-32. The adsorbent 350 may be an adsorbent other than a zeolite adsorbent as described in the first embodiment, and may be any adsorbent capable of adsorbing and desorbing the air-conditioning refrigerant.

Next, a specific refrigerant recovery method using the refrigerant recovery system 10A will be described. Figure 23 is a flowchart showing a specific refrigerant recovery method using the refrigerant recovery system 10A in embodiment 3.

In S500, the worker stops the air conditioning unit 12. In S501, the worker connects the refrigerant recovery unit 14 and the recovery cylinder 16 to the air conditioning unit 12. In S502, the worker connects the adsorption unit 418 to the upstream of the refrigerant recovery unit 14 and to the recovery cylinder 16.

Below, steps S503 to S507 show the processing of the recovery process. In step 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 in communication). In step S504, the control unit 430 drives the refrigerant recovery device 14 to start refrigerant recovery. This step may be performed by an operator.

In S505, the control unit 430 determines whether the detected pressure DP is greater than the reference pressure RP. In S506, the control unit 430 determines whether refrigerant remains in the refrigerant circuit 30.

If DP>RP (S505: YES), the control unit 430 ends the recovery process and proceeds to S508. If DP≦RP (S505: NO) and the control unit 430 determines that refrigerant remains in the refrigerant circuit 30 (S506: YES), the control unit 430 continues refrigerant recovery (S507) and returns the process to S505. In other words, the control unit 430 continues refrigerant recovery as long as 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), the control unit 430 proceeds to S517.

Below, S508 to S512 show the processing of the adsorption process. In S508, the control unit 430 operates 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 open. In this case, since the three-way valve 40 is already in the normal mode, there is no need to change the mode of the three-way valve 40.

The control unit 430 continues suction (S510) while it determines that DP>RP (S509: NO). If the control unit 430 determines that DP≦RP (S509: YES), it stops the suction device 418 (S511).

If the control unit 430 determines that the recovery of refrigerant from the refrigerant circuit 30 has been completed (S512: YES), the process proceeds to S513. This causes the process to move to the desorption process. On the other hand, if the control unit 430 determines that the recovery of refrigerant from the refrigerant circuit 30 has not been completed (S512: NO), the process returns to S506. This causes the process to return to the recovery process again.

Below, S513 to S516 show the processing of 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 exhaust valve 463 to a closed state, controls the three-way valve 40 to the circulation mode (the second port 42 and the third port 43 are in communication), and drives the pump of the refrigerant recovery device 14 to start the desorption process.

The control unit 430 continues detachment (S515) until a predetermined time (detachment time) required for the detachment process has elapsed (S514: NO). If the predetermined time (detachment time) has elapsed (S514: YES), the control unit 430 ends the detachment process (S516).

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

Next, the effects of the refrigerant recovery system 10A described above will be explained. The refrigerant recovery system 10A is a system that recovers air-conditioning refrigerant from the refrigerant circuit 30 of the air-conditioning device 12 as a refrigeration and air-conditioning device. The refrigerant recovery system 10A includes a recovery cylinder 16 as a first recovery device, an adsorption device 418, and a desorption device 419. The recovery cylinder 16 recovers compressed and condensed refrigerant produced 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 from the mixed gas 22 consisting of the gas component 423 of the air-conditioning refrigerant and the non-condensable gas 26 contained inside the recovery cylinder 16 that recovered the compressed condensed refrigerant. The desorption device 419 desorbs the gas component 423 of the air-conditioning refrigerant adsorbed by the adsorbent 350 and stores the desorbed gas component 423 of the air-conditioning refrigerant.

In this way, by operating the adsorption device 418, the mixed gas 22 containing the non-condensable gas 26 inside the recovery cylinder 16 can be extracted and the gas component 423 of the air-conditioning refrigerant from the mixed gas 22 can be adsorbed onto the adsorbent 350, and by operating the desorption device 419, the gas component 423 of the air-conditioning refrigerant can be desorbed from the adsorbent 350 and recovered, so that the adsorbent 350 can be reused repeatedly. This allows the gas contained in the recovery cylinder 16 to be suitably separated into the non-condensable gas 26 and the gas component of the air-conditioning refrigerant while reducing the non-condensable gas 26 in the recovery cylinder 16.

The adsorption module 468 includes an outlet 494 that releases the non-condensable gas 26 from the mixed gas 22 that has not been adsorbed by the adsorbent 350 to the atmosphere. This allows only the non-condensable gas 26 accumulated in the recovery cylinder 16 to be released to the atmosphere without mixing with the gas components of the air-conditioning refrigerant.

The desorption device 419 includes a pipe 58A, a refrigerant recovery device 14, and a recovery cylinder 16. One end of the pipe is connected to the adsorption module 468, and the other end is connected to the desorption device 419. The refrigerant recovery device 14 compresses and condenses the air-conditioning refrigerant to generate compressed and condensed refrigerant. The recovery cylinder 16 recovers the compressed and condensed refrigerant generated by the refrigerant recovery device 14. As a result, the gas component 423 of the air-conditioning refrigerant desorbed from the adsorbent 350 passes through the refrigerant recovery device 14, is compressed and condensed, and is recovered in the recovery cylinder 16 after liquefaction, so that the volume of the recovery cylinder 16 can be reduced and there is no need to prepare multiple recovery cylinders.

The adsorption device 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 disposed between the recovery cylinder 16 and the adsorption module 468. The three-way valve 40 is disposed between the refrigerant circuit 30 and the refrigerant recovery device 14. The exhaust valve 463 releases the non-condensable gas 26 of the mixed gas 22 that has not been adsorbed by the adsorbent 350 from the adsorption module 468 to 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 device 14. The third port 43 of the three-way valve 40 is connected to the pipe 58A. In an adsorption mode for adsorbing the gas component 423 of the air-conditioning refrigerant to the adsorbent 350, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to be open, and controls the three-way valve 40 so that the first port 41 and the second port 42 of the three-way valve 40 are in a communicating state. In a desorption mode for desorbing the gas component 423 of the air-conditioning refrigerant adsorbed to the adsorbent 350, the control unit 430 controls the inlet valve 64 and the exhaust valve 463 to be closed, and controls the three-way valve 40 so that the second port 42 and the third port 43 of the three-way valve 40 are in a communicating state. This allows the inlet valve 64, the three-way valve 40, and the exhaust valve 463 to be adsorbed by the adsorbent 350 and the non-condensable gas 26 to be released to the atmosphere, and further allows the gas component 423 of the air-conditioning refrigerant to be desorbed from the adsorbent 350.

The adsorbent 350 is a zeolite adsorbent. By using a zeolite adsorbent as the adsorbent 350, the gas component 423 of the air conditioning refrigerant can be adsorbed and desorbed effectively.

The gas component 423 of the air conditioning refrigerant is R-32. This allows R-32 to be adsorbed and desorbed effectively.

It is anticipated that the embodiments disclosed herein may be combined as appropriate to the extent that no technical contradictions arise. The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The technical scope of this disclosure is defined by the claims, not the description of the embodiments above, and is intended to include all modifications within the meaning and scope of the claims.

10, 10A, 10B refrigerant recovery system, 12 air conditioning device, 14 refrigerant recovery device, 16 recovery cylinder, 18 separation device (adsorption device), 19 desorption device, 20 recovery tank, 22, 24 mixed gas, 23 first gas component of air conditioning refrigerant, 25 second gas component of air conditioning refrigerant (gas component of air conditioning refrigerant), 26 non-condensable gas, 28 water, 29 other gas components, 30 refrigerant circuit, 32 accumulator, 34 service port, 36, 90A, 90B inlet, 37, 61, 70 pressure detector, 38, 96A outlet, 40 three-way valve, 41 first port , 42 second port, 43 third port, 46 liquid inlet/outlet, 48 gas inlet/outlet, 49 branch pipe, 50 connection pipe, 52 front pipe, 54 rear pipe, 56 delivery pipe, 57A, 57B pipe, 58A, 58B, 58C return pipe, 59, P1, P2 pipe, 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 delivery controller, 78 return controller, 80 three-way valve controller, 88A housing, 92A separation membrane , 94, 94A, 94B discharge port, 97, 97A pressure controller, 98A first pressure regulator, 98B second pressure regulator, 99A first check valve, 100 input section, 102, 102A memory section, 104 reference pressure acquirer, 106 pressure reducing valve controller, 108, 118 judger, 110 recovered refrigerant information, 112 pressure characteristics, 120 pressure threshold, 122 duration, 211, 211A pressure acquirer, 212 first pressure controller, 213 second pressure controller, 214 first pressure information, 215 second pressure information, 253 sensor, 254 bypass controller, 315 adsorption section, 3 20 Switching valve, 321 First adsorption unit, 322 Second adsorption unit, 323 Third adsorption unit, 324 Refrigerant detection sensor, 330 Control unit, 350 Adsorption agent, 402 Three-way valve, 411 First port, 412 Second port, 413 Third port, 415 Adsorption unit, 418 Adsorption device, 419 Desorption device, 423 Gas component of air-conditioning refrigerant, 424 Pipe, 430 Control unit, 440 Pump, 461 Control valve, 462 Desorption valve, 463 Exhaust valve, 468 Adsorption module, 470 Recovery cylinder, 490 Inlet, 494 Discharge port, 496 Outlet.

Claims (9)

A refrigerant recovery system that recovers air-conditioning refrigerant from a refrigerant circuit of a refrigeration and air-conditioning equipment,
a first recovery device that recovers a compressed and condensed refrigerant produced by compressing and condensing the air-conditioning refrigerant;
an adsorption device including an adsorption module having an adsorbent that adsorbs the gas component of the air-conditioning refrigerant in a mixed gas composed of a gas component of the air-conditioning refrigerant and a non-condensable gas contained inside the first recovery device that recovered the compressed condensed refrigerant;
a desorption device that desorbs the gas components of the air-conditioning refrigerant adsorbed by the adsorbent and accumulates the desorbed gas components of the air-conditioning refrigerant. The refrigerant recovery system of claim 1, wherein the adsorption module includes an outlet for discharging the non-condensable gas of the mixed gas that has not been adsorbed by the adsorbent to the atmosphere. The detachment device is
a second recovery device that accumulates the gas component of the desorbed air-conditioning refrigerant;
a pipe having one end connected to the adsorption module and the other end connected to the second recovery device;
3. The refrigerant recovery system according to claim 1 or 2, further comprising: a suction device that suctions the gas component of the air-conditioning refrigerant adsorbed by the adsorbent and delivers the gas component to the second recovery device. The detachment device is
a pipe having one end connected to the adsorption module and the other end connected to the desorption device;
a refrigerant recovery device that generates the compressed and condensed refrigerant by compressing and condensing the air-conditioning refrigerant;
the first recovery equipment recovering the compressed condensed refrigerant produced by the refrigerant recovery device. The adsorption device is
an inlet valve disposed between the first recovery device and the adsorption module;
a three-way valve disposed between the refrigerant circuit and the refrigerant recovery device;
an exhaust valve that releases the non-condensable gas that is not adsorbed by the adsorbent from the mixed gas to the atmosphere from the adsorption module;
a control unit that 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 being connected to the refrigerant circuit, the second port of the three-way valve being connected to the refrigerant recovery device, and the third port of the three-way valve being connected to the piping;
The control unit is
in an adsorption mode for adsorbing the gas component of the air-conditioning refrigerant into the adsorbent, controlling the inlet valve and the exhaust valve to be opened, and controlling the three-way valve so that the first port and the second port of the three-way valve are in a communication state;
5. The refrigerant recovery system according to claim 4, wherein, in a desorption mode for desorbing the gas component of the air-conditioning refrigerant adsorbed by the adsorbent, the inlet valve and the exhaust valve are controlled to be closed, and the three-way valve is controlled so that the second port and the third port of the three-way valve are in a communicating state. the adsorption device further includes a gas separation module including a separation membrane that separates the mixed gas into a first gas component of the air-conditioning refrigerant and a second mixed gas consisting of a second gas component of the air-conditioning refrigerant and the non-condensable gas;
The adsorbent of 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 detachment device is
a refrigerant recovery device that generates the compressed and condensed refrigerant by compressing and condensing the air-conditioning refrigerant;
the first recovery device recovering the compressed condensed refrigerant produced by the refrigerant recovery device;
2. The refrigerant recovery system of claim 1, further comprising a re-transmission pipe including a first re-transmission pipe into which the first gas component of the air-conditioning refrigerant separated by the gas separation module flows, a second re-transmission pipe into which the second gas component of the air-conditioning refrigerant desorbed from the adsorbent flows, and a third re-transmission pipe for mixing the first gas component and the second gas component and re-transmitting them between the refrigerant circuit and the refrigerant recovery device. The refrigerant recovery system according to any one of claims 1 to 6, wherein the adsorbent is a zeolite adsorbent. The refrigerant recovery system according to any one of claims 1 to 7, wherein the gas component of the air conditioning refrigerant is R-32. A refrigerant recovery method for recovering air-conditioning refrigerant from a refrigerant circuit of a refrigeration and air-conditioning equipment, comprising:
A first recovery device recovers a compressed and condensed refrigerant generated by compressing and condensing the air-conditioning refrigerant;
A step in which an adsorbent of an adsorption module of an adsorption device adsorbs the gas component of the air-conditioning refrigerant from a mixed gas of the gas component of the air-conditioning refrigerant and a non-condensable gas contained inside the first recovery device that recovered the compressed condensed refrigerant;
a desorption device desorbing the gas component of the air-conditioning refrigerant adsorbed by the adsorbent, and storing the desorbed gas component of the air-conditioning refrigerant.

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