JP7645995B2 - Refrigeration System - Google Patents

Description

The present disclosure relates to a refrigeration system having a refrigerant circuit through which a flammable refrigerant circulates.

Conventionally, there is a refrigeration system equipped with a refrigerant circuit in which a flammable refrigerant circulates (see, for example, Patent Document 1). The refrigeration system of Patent Document 1 includes an air conditioner, a ventilation device, and a refrigerant leak detection device. In Patent Document 1, when a refrigerant leak is detected by the refrigerant leak detection device, the ventilation device is operated to exhaust the flammable refrigerant from the space in which the refrigerant leak has occurred. In addition, in Patent Document 1, when a refrigerant leak is detected and the ventilation device is operating with insufficient airflow, the airflow of the air conditioner is increased to prevent the leaked flammable refrigerant from accumulating in the space and to exhaust it from the space.

JP 2016-223643 A

In Patent Document 1, a ventilation system is essential, so in spaces where no ventilation system is installed, such as basements or warehouses, it is difficult to discharge the flammable refrigerant from the space. If the flammable refrigerant cannot be discharged from the space, it will remain in the space, which is an insufficient measure against refrigerant leakage.

The present disclosure has been made to solve the problems described above, and aims to provide a refrigeration system that is capable of reducing flammable refrigerant in a space where a refrigerant leak has occurred, even without a ventilation device.

The refrigeration system according to the present disclosure comprises a refrigeration unit having a refrigerant circuit including a compressor, a condenser, a pressure reducing device, and an evaporator, which are connected by refrigerant piping to allow a flammable refrigerant to circulate; a refrigerant leak detection device that detects a refrigerant leak from the refrigerant circuit of the refrigeration unit; and an air cleaning device that removes the flammable refrigerant from the air it takes in, and that starts operating only when a refrigerant leak is detected by the refrigerant leak detection device and is not operated constantly .

In the refrigeration system disclosed herein, when a refrigerant leak is detected, the air cleaning device starts operating and removes flammable refrigerant from the air that is taken in, thereby reducing the amount of flammable refrigerant in the space where the refrigerant leak has occurred even without a ventilation device.

1 is a schematic configuration diagram of a refrigeration system according to a first embodiment. FIG. 2 is an explanatory diagram of a control system of the refrigeration system according to the first embodiment. 1 is a diagram showing an example of an air cleaning device according to a first embodiment; 5 is a diagram showing another example of the air cleaning device according to the first embodiment. FIG. 4 is a flowchart showing the operation of the refrigeration system according to the first embodiment. FIG. 4 is a diagram showing another configuration example of the refrigeration system according to the first embodiment. FIG. 4 is a diagram showing another configuration example of the refrigeration system according to the first embodiment. FIG. 11 is a schematic configuration diagram of a refrigeration system according to a second embodiment. 10 is a flowchart showing the operation of a refrigeration system according to a second embodiment.

The following describes a refrigeration system according to an embodiment with reference to the drawings. In the following drawings, including FIG. 1, the same reference numerals denote the same or equivalent parts, and are common throughout the embodiments described below. The forms of the components shown in the entire specification are merely examples, and are not limited to the forms described in the specification. In addition, the highs and lows of temperature, pressure, etc. are not determined in relation to absolute values, but are determined relatively in terms of the state or operation of a system or device, etc.

Embodiment 1.
Fig. 1 is a schematic configuration diagram of a refrigeration system according to embodiment 1. Fig. 2 is an explanatory diagram of a control system of the refrigeration system according to embodiment 1. Here, a case will be described in which a refrigeration device provided in the refrigeration system is a cooling device dedicated to cooling.
The refrigeration system 50 includes a refrigeration device 300 and an air cleaning device 400. The refrigeration device 300 includes an outdoor unit 100 and an indoor unit 200, such as a showcase. The outdoor unit 100 is disposed in an outdoor space 60. The indoor unit 200 is disposed in an indoor space 70, such as a machine room or a warehouse. The air cleaning device 400 is disposed in both the indoor space 70 and the outdoor space 60. The air cleaning device 400 may be disposed in either the indoor space 70 or the outdoor space 60.

The outdoor unit 100 and the indoor unit 200 are connected by a liquid extension pipe 12 and a gas extension pipe 13. The outdoor unit 100 includes a compressor 1, an oil separator 2, a condenser 3, a liquid receiver 4, a subcooling heat exchanger 5, a fan 3a, a dryer 6, and an accumulator 9. The indoor unit 200 includes a pressure reducing device 7, an evaporator 8, and a fan 8a, which are configured with an expansion valve or a capillary tube. The compressor 1, the oil separator 2, the condenser 3, the liquid receiver 4, the subcooling heat exchanger 5, the dryer 6, the pressure reducing device 7, the evaporator 8, and the accumulator 9 are connected by a refrigerant pipe 10 to form a refrigerant circuit A in which the refrigerant circulates.

Here, a highly flammable refrigerant such as propane (R290) or isobutane is used as the refrigerant circulating through the refrigerant circuit A. A slightly flammable refrigerant such as R32, R1234yf or R463A-J may also be used as the refrigerant. In the following, there is no distinction between highly flammable refrigerants and slightly flammable refrigerants and they will be collectively referred to as flammable refrigerants.

The compressor 1 sucks in the refrigerant and compresses it to a high temperature and high pressure state. The oil separator 2 separates the oil contained in the refrigerant discharged from the compressor 1. The condenser 3 cools and condenses the refrigerant discharged from the compressor 1. The receiver 4 is disposed between the condenser 3 and the subcooling heat exchanger 5, and is a container for storing the excess refrigerant liquefied in the refrigerant circuit A. The subcooling heat exchanger 5 has a high-pressure side flow path through which the high-pressure refrigerant flows and a low-pressure side flow path through which the low-pressure refrigerant flows, and exchanges heat between the high-pressure refrigerant and the low-pressure refrigerant. The dryer 6 removes foreign matter contained in the refrigerant. The foreign matter includes impurities and moisture. The accumulator 9 stores the excess refrigerant. The evaporator 8 heats and evaporates the refrigerant flowing out from the pressure reducing device 7.

The refrigerant circuit A further includes an injection pipe 5b that branches off between the subcooling heat exchanger 5 and the dryer 6 and is connected to the suction side of the compressor 1 via the low-pressure side flow path of the subcooling heat exchanger 5. A pressure reducing device 5a, for example, composed of an expansion valve, is connected to the injection pipe 5b.

The refrigeration device 300 also includes a first temperature sensor TH1, a second temperature sensor TH2, a third temperature sensor TH3, and a fourth temperature sensor TH4. Temperature information measured by the first temperature sensor TH1, the second temperature sensor TH2, the third temperature sensor TH3, and the fourth temperature sensor TH4 is input to the control device 30 described below.

The first temperature sensor TH1 is provided at a position somewhere in the flow path from the outlet side of the condenser 3 to the inlet side of the subcooling heat exchanger 5, and measures the temperature of the refrigerant. Hereinafter, the temperature measured by the first temperature sensor TH1 will be referred to as the "subcooling heat exchanger inlet temperature th1." Note that the pressure may be measured by a pressure sensor, and the value converted into the saturation temperature may be used as the subcooling heat exchanger inlet temperature th1.

The second temperature sensor TH2 is provided at a position somewhere in the flow path from the outlet side of the subcooling heat exchanger 5 to the inlet side of the pressure reducing device 7, and measures the temperature of the refrigerant. Hereinafter, the temperature measured by the second temperature sensor TH2 is referred to as the "subcooling heat exchanger outlet temperature th2."

The third temperature sensor TH3 measures the temperature of the air exchanging heat with the refrigerant in the condenser 3. Hereinafter, the temperature measured by the third temperature sensor TH3 is referred to as the "outside air temperature th3."

The fourth temperature sensor TH4 measures the temperature of the refrigerant injected into the compressor 1. Hereinafter, the temperature measured by the fourth temperature sensor TH4 is referred to as the "injection temperature tc."

The air cleaning device 400 is a device that removes flammable refrigerant from the air taken into the air cleaning device 400. The configuration of the air cleaning device 400 is shown in the following Figures 3 and 4.

Fig. 3 is a diagram showing an example of the air cleaning device 400 according to the embodiment 1. Fig. 4 is a diagram showing another example of the air cleaning device 400 according to the embodiment 1.
3 and 4, the air cleaning device 400 includes a filter 401, a fan motor 402, and a fan 403 that is driven by the fan motor 402 to take in air from the outside and pass the air through the filter 401. The filter 401 removes flammable refrigerant from the air passing through the filter 401. The air cleaning device 400 may further include a filter that removes dust and the like from the air taken into the air cleaning device 400.

The filter 401 has an adsorbent that adsorbs the flammable refrigerant, and the flammable refrigerant is adsorbed by the adsorbent to remove the flammable refrigerant from the air passing through the filter 401 and clean the air. When the flammable refrigerant is propane gas, for example, zeolite or activated carbon is used as the adsorbent. The filter 401 may have a decomposition catalyst that chemically reacts with the flammable refrigerant and decomposes the refrigerant to make it non-combustible, and may decompose the flammable refrigerant to remove the flammable refrigerant from the air passing through the filter 401 and clean the air. When the flammable refrigerant is propane gas, a cobalt-based or nickel-based catalyst is used as the decomposition catalyst. The decomposition catalyst is heated before use. The air cleaning device 400 may also be equipped with both a filter 401 with an adsorbent and a filter 401 with a decomposition catalyst.

There are two types of air cleaning devices 400: one that blows air in the side direction and one that blows air in the top direction, which are shown in Figures 3 and 4. Figure 3 shows a side-blowing type air cleaning device 400. In the side-blowing type, air containing flammable refrigerant is sucked into the air cleaning device 400 from the side, as shown by the outlined arrow. The sucked-in air containing flammable refrigerant is then cleaned by passing through filter 401, which removes the flammable refrigerant, and the cleaned air is then blown out from the side as is.

Figure 4 shows a top-blowing type air cleaning device 400. In the top-blowing type, air containing flammable refrigerant is sucked into the air cleaning device 400 from both the left and right sides, as shown by the white arrows. The sucked-in air containing flammable refrigerant is then passed through a filter 401, where the flammable refrigerant is removed and the air is cleaned, and the cleaned air is blown out from above.

The air cleaning device 400 is disposed adjacent to the indoor unit 200 from the viewpoint of quickly removing the leaked flammable refrigerant. When the air cleaning device 400 is disposed in the outdoor space 60, it is disposed adjacent to the outdoor unit 100. In short, the air cleaning device 400 is disposed adjacent to the refrigeration device 300. Also, since the flammable refrigerant is heavier than air, the air cleaning device 400 is disposed at a height below the position where the refrigeration device 300 is disposed. Specifically, the air cleaning device 400 is disposed at a height below the position where the indoor unit 200 is disposed. Note that, when the air cleaning device 400 is disposed in the outdoor space 60, the air cleaning device 400 is disposed at a height below the position where the outdoor unit 100 is disposed. Since the flammable refrigerant is heavier than air, the air cleaning device 400 is disposed at the above position, so that the flammable refrigerant can be quickly removed.

The refrigeration system 50 further includes a control device 30 that controls the entire refrigeration system. The control device 30 is, for example, a microcomputer and includes a CPU, RAM, ROM, etc. The ROM stores a control program and a program corresponding to the flowchart of FIG. 5 described below.

The control device 30 is equipped with a refrigerant leak detection device 31 and a cleaning control device 32. The refrigerant leak detection device 31 detects a refrigerant leak from the refrigerant circuit A based on temperature information measured by temperature sensors TH1 to TH4. The cleaning control device 32 controls the air cleaning device 400 based on the detection result of the refrigerant leak detection device 31. Furthermore, when a refrigerant leak is detected by the refrigerant leak detection device 31, the control device 30 issues a refrigerant leak alarm from a display device (not shown) or an audio output device (not shown), etc.

Next, the refrigerant leak detection operation of the refrigerant leak detection device 31 will be described.
The refrigerant leak detection operation in the refrigerant leak detection device 31 is not particularly limited, and a conventionally known method such as that disclosed in JP 2012-132639 A can be adopted. Hereinafter, this known refrigerant leak detection method will be briefly described.

When a refrigerant leak occurs, the refrigerant leak detection device 31 determines whether or not there is a refrigerant leak by using the fact that the subcooling efficiency ε of the subcooling heat exchanger 5 decreases. The subcooling efficiency ε of the subcooling heat exchanger 5 is a value obtained by dividing the "degree of subcooling of the refrigerant at the outlet of the subcooling heat exchanger 5" by the "calculated temperature" calculated using the subcooling heat exchanger inlet temperature th1 and the outside air temperature th3, and is expressed by the following formula 1. The "degree of subcooling of the refrigerant at the outlet of the subcooling heat exchanger 5" is the temperature difference between the subcooling heat exchanger inlet temperature th1 and the subcooling heat exchanger outlet temperature th2. The "degree of subcooling of the refrigerant at the outlet of the subcooling heat exchanger 5" is calculated by the subcooling heat exchanger inlet temperature th1 - the subcooling heat exchanger outlet temperature th2.

The "calculated temperature" is the temperature difference between the subcooling heat exchanger inlet temperature th1 and the outside air temperature th3. The "calculated temperature" is calculated by subtracting the outside air temperature th3 from the subcooling heat exchanger inlet temperature th1. The "calculated temperature" may use the injection temperature tc instead of the outside air temperature th3. In other words, the "calculated temperature" may be the temperature difference between the subcooling heat exchanger inlet temperature th1 and the injection temperature tc. The subcooling efficiency ε when the injection temperature tc is used is expressed by the following equation 2.

The refrigerant leak detection device 31 uses the subcooling efficiency ε calculated when the current operating state is not one of the detection-unavailable conditions described below as an effective value for refrigerant leak detection. The effective value of the subcooling efficiency ε is greater than 0 and less than 1.5. The refrigerant leak detection device 31 calculates the subcooling efficiency ε at a set detection cycle. Then, when a set number of calculations (e.g., 10 times) have been completed, if all of the subcooling efficiencies obtained at that time are valid values, the effective values for the set number of calculations are used to calculate the average subcooling temperature efficiency.

If the average subcooling efficiency is detected to be less than the preset judgment threshold a set number of times in succession, the refrigerant leak detection device 31 determines that a refrigerant leak exists. As described above, the calculation of the subcooling efficiency ε is performed at a set detection period, so in other words, the refrigerant leak detection device 31 determines that a refrigerant leak exists when the average temperature efficiency is less than the preset judgment threshold continuously for a set period of time. Here, the detection impossible condition corresponds to, for example, a case where the compressor 1 is stopped or the temperature efficiency is not stable for 30 minutes after startup.

Note that, although the configuration has been described here in which the refrigerant leak detection device 31 calculates the subcooling efficiency ε based on temperature information measured by temperature sensors TH1 to TH4 and detects a refrigerant leak, the following configuration may also be used. That is, the refrigerant leak detection device 31 may be equipped with a gas sensor that detects the refrigerant concentration, for example, and may detect a refrigerant leak based on the refrigerant concentration detected by the gas sensor. Also, while FIG. 1 shows a configuration in which the refrigerant leak detection device 31 is located on the outdoor unit 100 side, it may be provided on both the outdoor unit 100 and the indoor unit 200.

Next, the flow of refrigerant in the refrigerant circuit A will be described.
The high-temperature, high-pressure gas refrigerant discharged from the compressor 1 flows into the condenser 3 after the refrigeration oil contained in the refrigerant is separated by the oil separator 2. The high-temperature, high-pressure gas refrigerant that flows into the condenser 3 exchanges heat with the outdoor air blown by the fan 3a in the condenser 3 and condenses into a high-pressure liquid refrigerant or a two-phase refrigerant, which is stored in the receiver 4. The refrigerant that flows out of the receiver 4 flows into the high-pressure side flow path of the supercooling heat exchanger 5, and exchanges heat with the refrigerant passing through the low-pressure side flow path of the supercooling heat exchanger 5, thereby becoming a supercooled high-pressure liquid refrigerant. The high-pressure liquid refrigerant that flows out of the supercooling heat exchanger 5 then flows into the dryer 6, where foreign matter is removed. The liquid refrigerant that flows out of the dryer 6 is depressurized by the pressure reducing device 7 of the indoor unit 200 to become a low-temperature, low-pressure two-phase refrigerant, and flows into the evaporator 8. The refrigerant that has flowed into the evaporator 8 exchanges heat with the indoor air blown by the fan 8 a and evaporates, becoming a low-temperature, low-pressure gas refrigerant, which then returns to the compressor 1 via the accumulator 9 .

In addition, a portion of the refrigerant flowing out from the high-pressure side of the subcooling heat exchanger 5 is depressurized by the pressure reducing device 5a and flows into the low-pressure side flow path of the subcooling heat exchanger 5, where it exchanges heat with the refrigerant flowing through the high-pressure side flow path of the subcooling heat exchanger 5, and is then injected into the compressor 1.

The configuration of the refrigerant circuit A is not limited to the configuration shown in FIG. 1. For example, a four-way valve that switches the refrigerant flow path may be provided to switch between cooling and heating operations. The refrigerant circuit A may also be configured for heating only. When the refrigerant circuit A is used for heating only, the outdoor heat exchanger installed in the outdoor unit 100 functions as an evaporator, and the indoor heat exchanger installed in the indoor unit 200 functions as a condenser. The refrigerant circuit A may also be configured without at least one of the oil separator 2, the receiver 4, and the accumulator 9. In short, the refrigerant circuit A may be configured to include at least the compressor 1, the condenser 3, the pressure reducing device 5a, and the evaporator 8.

Next, the operation of the refrigeration system 50 will be described.

FIG. 5 is a flowchart showing the operation of the refrigeration system according to the first embodiment.
When the start of the refrigerant leak detection operation is instructed in the refrigeration system 50, the refrigerant leak detection device 31 starts the above-mentioned refrigerant leak detection operation (step S1). When the refrigerant leak detection device 31 detects a refrigerant leak (step S2), the control device 30 issues a refrigerant leak alarm from a display device (not shown) or a voice output device (not shown) (step S3).

When the refrigerant leak detection device 31 detects a refrigerant leak, the control device 30 starts a pump-down operation to recover the refrigerant in the refrigerant circuit A to the receiver 4 (step S4). The pump-down operation is performed to reduce the amount of refrigerant leaking from the refrigerant circuit A. In addition, when a refrigerant leak is detected, the cleaning control device 32 starts the operation of the air cleaning device 400 (step S5). Since it is unclear at which point in the refrigerant circuit A the refrigerant leak is occurring, the cleaning control device 32 starts the operation of the air cleaning device 400 in both the indoor space 70 and the outdoor space 60.

The air cleaning device 400 sets the rotation speed of the fan motor 402 to the rated rotation speed, which is the maximum rotation speed in operation, and operates the fan 403 at full speed. By operating the fan 403 at full speed, the flow rate of air containing flammable refrigerant taken into the air cleaning device 400 increases, allowing the flammable refrigerant to be quickly removed and the air around the air cleaning device 400 to be stirred. In this way, it is desirable to set the rotation speed of the fan motor 402 to the rated rotation speed from the viewpoint of quickly removing the flammable refrigerant, but it is not limited to the rated rotation speed. When multiple air cleaning devices 400 are installed, the rotation speed of the fan motor 402 of all air cleaning devices 400 may be set to the maximum rotation speed in operation when a refrigerant leak is detected. The air cleaning device 400 stops operation after operating for a preset set time (step S6). In order to trap the adsorbed refrigerant, the air cleaning device 400 is configured not to be restarted until the filter 401 is replaced after stopping operation (step S6).

After starting the pump-down operation in step S4, when the recovery of the refrigerant in the refrigerant circuit A is completed, the control device 30 ends the pump-down operation (step S7). After stopping the pump-down operation, the inspector repairs the refrigerant leak (step S8) and restarts the refrigeration device 300 (step S9).

In the above, an example in which the operations of steps S4 and S5 start simultaneously has been described, but this is not limited thereto, and the operations may start sequentially at a preset time interval. Also, in step S4, the control device 30 may start the pump-down operation after a preset time has elapsed since the refrigerant leak detection device 31 detected a refrigerant leak.

In step S5, the operation of the air cleaning device 400 is not limited to a preset time, and the operation time may be changed according to the refrigerant concentration in the indoor space 70. The operation of the air cleaning device 400 may be continued for a preset time as necessary even after the pump-down operation of the refrigeration device 300 is stopped. A sensor that measures the concentration of the flammable refrigerant may be installed, and the operation of the air cleaning device 400 may be continued until the measured concentration falls to a specific safe level, and the operation of the air cleaning device 400 may be stopped when the measured concentration falls below the safe level.

In addition, the pump-down operation in step S4 is effective in terms of suppressing the amount of refrigerant leakage from the refrigerant circuit A in the event of a refrigerant leak, but can be omitted. The refrigeration system 50 only needs to be configured to operate the air cleaning device 400 at least when a refrigerant leak is detected.

In this way, in the refrigeration system 50, when a refrigerant leak is detected, the air cleaning device 400 starts operating and flammable refrigerant is removed from the air taken in. Therefore, even without a ventilation device, the refrigeration system 50 can reduce the amount of flammable refrigerant in the space where the refrigerant leak occurs, thereby improving safety. In the above, when a refrigerant leak is detected, the air cleaning device 400 in both the outdoor space 60 and the indoor space 70 starts operating, but it may be as follows. If the refrigerant leak detection device 31 is placed in both the indoor unit 200 and the outdoor unit 100 as, for example, a gas sensor, it is possible to identify whether the refrigerant leak occurred in the indoor unit 200 or the outdoor unit 100. In this case, the refrigeration system 50 may start operating only the air cleaning device 400 installed in the space where the refrigerant leak occurred.

In addition, when a refrigerant leak is detected, the refrigeration system 50 initiates pump-down operation, so that the refrigerant in the refrigerant circuit A can be quickly recovered to the receiver 4, thereby reducing the amount of refrigerant leaking from the refrigerant circuit A.

In the past, a method for detecting refrigerant leaks involved visually checking for flash gas, which is air bubbles in the refrigerant, through a glass window installed in the refrigerant piping, and determining that a refrigerant shortage caused by a refrigerant leak was caused by the refrigerant leak if flash gas was generated. In this state where flash gas was generated, the subcooling efficiency ε was close to zero, resulting in an uncooled state. As a result of comparison in tests, it was found that the time from when a refrigerant leak was detected using the refrigerant leak detection operation using the subcooling efficiency ε of the first embodiment until flash gas was generated took about 1 to 6 hours, depending on the amount of refrigerant or the amount of leakage. In other words, the method for checking for refrigerant leaks by visually checking for flash gas results in a significant delay in detection compared to the above-mentioned refrigerant leak detection operation.

In contrast, the refrigeration system 50 of the first embodiment detects refrigerant leaks using the subcooling efficiency ε, making it possible to detect refrigerant leaks before flash gas is generated. As a result, the refrigeration system 50 can reduce the amount of refrigerant released into the atmosphere, improving product reliability and reducing cost losses.

The refrigeration system 50 is not limited to the configuration shown in FIG. 1 or FIG. 2, and can be modified, for example as follows, without departing from the gist of this disclosure.

In the first embodiment, the refrigeration device 300 is a refrigeration device dedicated to cooling, but it may be an air conditioner that air-conditions the room. In addition, the refrigeration device 300 is not limited to the air-cooled refrigeration device described above, and may be a water-cooled refrigeration device.

In addition, in this embodiment 1, a configuration in which one indoor unit 200 is connected to one outdoor unit 100 has been described, but this is not limited to this, and any number of indoor units 200 may be connected.

In addition, in this embodiment 1, a configuration in which one refrigeration device 300 is connected to one control device 30 has been described, but this is not limited to this, and any number of refrigeration devices 300 may be connected.

In addition, when the refrigeration unit 300 is installed on site, the outdoor unit 100 and the indoor unit 200 arranged on site may be joined by refrigerant piping 10 to form a refrigerant circuit A.

The refrigeration system 300 can also be a remote condensing unit as shown in Figure 6 below.

FIG. 6 is a refrigerant circuit diagram when the refrigeration apparatus according to the first embodiment is a remote condensing unit.
The remote-type condensing unit includes a compression unit 500 disposed in the indoor space 70. The compression unit 500 includes the components included in the outdoor unit 100 in Fig. 1 except for the condenser 3 and the third temperature sensor TH3. The condenser 3 and the third temperature sensor TH3 are installed in the outdoor unit 100A.

The refrigeration device 300 may also be a single unit, such as a cooling unit, having each device that constitutes the refrigerant circuit A and other auxiliary devices within a single housing, and connected by refrigerant piping 10.

The refrigeration system 50 may also be equipped with an air conditioner as shown in Figure 7 below.

FIG. 7 is a diagram showing another configuration example of the refrigeration system according to the first embodiment.
The refrigeration system 50 includes an air conditioner 800 that performs indoor air conditioning in addition to the refrigeration device 300 and the air cleaning device 400. The air conditioner 800 includes an outdoor unit 600 and an indoor unit 700. The outdoor unit 600 and the indoor unit 700 are provided with a refrigerant circuit (not shown) similar to the refrigerant circuit A, and perform indoor air conditioning by circulating refrigerant through the refrigerant circuit. The air conditioner 800 adjusts the temperature of the air taken in from the outside by passing it through a heat exchanger of the refrigerant circuit, and blows the temperature-adjusted air to the outside. The air conditioner 800 is connected to the control device 30 and controlled by the control device 30. The outdoor unit 600 and the indoor unit 700 are provided with fans that blow air to the heat exchangers provided inside them.

When the refrigeration system 50 includes an air conditioner 800, the air conditioner 800 may include an air cleaning device 400. When the air conditioner 800 includes an air cleaning device 400, the air conditioner 800 may include a filter 401 in one or both of the outdoor unit 600 and the indoor unit 700 of the air conditioner 800. The fan 403 and the fan motor 402 of the air cleaning device 400 may be replaced by those provided in the outdoor unit 600 and the indoor unit 700. When the air conditioner 800 includes an air cleaning device 400, the filter 401 may be replaced periodically. The refrigeration system 50 may include an air conditioner 800 including an air cleaning device 400, and may include a separate air cleaning device 400.

In addition, in the first embodiment, the refrigeration device 300 provided in the refrigeration system 50 is a cooling device, but it may be an air conditioner. If the refrigeration device 300 is an air conditioner, the air conditioner may be configured to incorporate the air cleaning device 400 as described above.

In addition, in this embodiment 1, the operation of the air cleaning device 400 is started when a refrigerant leak is detected, but the air cleaning device 400 may be configured to always operate regardless of whether a refrigerant leak is detected or not.

In addition, if the indoor unit 200 is a showcase, the showcase fan is always running, so after a leak is detected, the fan's airflow can be increased (full speed) or the fan flow can be changed to blow air onto the adsorbent.

In addition, a separate circulator may be provided near the air cleaning device 400 and operated to blow air in the direction of the adsorbent after a refrigerant leak is detected. The circulator may be in operation before a refrigerant leak is detected, or may start operating in conjunction with the air cleaning device 400 after detection.

As described above, the refrigeration system 50 of the first embodiment includes a refrigeration device 300 having a refrigerant circuit A in which a flammable refrigerant circulates, the refrigeration device 300 including a compressor 1, a condenser 3, a pressure reducing device 7, and an evaporator 8, which are connected by a refrigerant pipe 10. The refrigeration device 300 further includes a refrigerant leak detection device 31 that detects a refrigerant leak from the refrigerant circuit A of the refrigeration device 300, and an air cleaning device 400 that starts operation when a refrigerant leak is detected by the refrigerant leak detection device 31 and removes the flammable refrigerant from the air that is taken in.

In this way, the refrigeration system 50 starts operation of the air cleaning device 400 when a refrigerant leak is detected, and removes flammable refrigerant from the air taken in, so that the amount of flammable refrigerant in the space where the refrigerant leak occurred can be reduced even without a ventilation device. As a result, the refrigeration system 50 can be configured as a highly safe system. In addition, because the air cleaning device 400 starts operation when a refrigerant leak is detected, it is possible to suppress a decrease in the adsorption or decomposition ability of flammable refrigerant compared to when it is operated constantly, and the capacity can be maintained for a long period of time.

In addition, the air cleaning device 400 is equipped with one or both of a filter 401 having an adsorbent that adsorbs flammable refrigerant and a filter 401 having a decomposition catalyst that chemically reacts with the flammable refrigerant and decomposes the flammable refrigerant to make it non-combustible.

The refrigeration system 50 is capable of removing flammable refrigerant from the air taken in by the air cleaning device 400 being equipped with such a filter 401.

The refrigeration device 300 provided in the refrigeration system 50 is an air conditioner 800 that adjusts the temperature of air taken in from the outside by passing it through a condenser 3 or an evaporator 8, and blows the temperature-adjusted air to the outside, and the air conditioner 800 is provided with an air cleaning device 400.

In this way, when the refrigeration device 300 is an air conditioner 800, the air conditioner 800 can be configured to incorporate an air cleaning device 400.

The air purification device 400 is equipped with a fan 403 that takes in air from the outside, and the fan 403 operates at full speed if a refrigerant leak is detected.

This enables the refrigeration system 50 to quickly reduce flammable refrigerant in the event of a refrigerant leak.

The air cleaning device 400 is positioned at a height below the position of the refrigeration device 300.

This allows the refrigeration system 50 to quickly reduce flammable refrigerant that is heavier than air.

In addition, the refrigeration system 50 performs pump-down operation to recover flammable refrigerant in the receiver 4 if a refrigerant leak is detected.

This enables the refrigeration system 50 to reduce the amount of refrigerant leakage from the refrigerant circuit A in the event of a refrigerant leak.

Embodiment 2.
Fig. 8 is a schematic configuration diagram of a refrigeration system according to embodiment 2. The following description will focus on configurations of embodiment 2 that are different from embodiment 1, and configurations not described in embodiment 2 are similar to embodiment 1.

The refrigeration system 50 of embodiment 2 is configured such that a leak detection agent circulates together with a flammable refrigerant in the refrigerant circuit A of the refrigeration system 50 of embodiment 1. The refrigeration system 50 is provided with a leak detection agent dosing device 20. The control device 30 of the refrigeration system 50 of embodiment 2 is provided with a dosing control device 33 that controls the leak detection agent dosing device 20.

The leak detection agent injection device 20 is connected to the refrigerant piping 10 of the refrigerant circuit A and injects the leak detection agent into the refrigerant piping 10. The leak detection agent is a fluorescent agent, which emits light when exposed to ultraviolet light from an ultraviolet lamp. An inspector can easily identify the location of a refrigerant leak by irradiating the ultraviolet light from the ultraviolet lamp to a location where a refrigerant leak is suspected. The leak detection agent may be, for example, a coloring agent, an odor-emitting agent, or an agent that produces bubbles in the air. The leak detection agent injection device 20 is disposed downstream of the oil separator 2 so that the leak detection agent 23 is not separated in the oil separator 2. FIG. 8 shows an example in which the leak detection agent injection device 20 is connected to the refrigerant piping 10 between the oil separator 2 and the condenser 3, but it may also be connected to the refrigerant piping 10 between the evaporator 8 and the compressor 1. The leak detection agent injection device 20 may be connected to the refrigerant piping 10 downstream of the oil separator 2.

The number of leak detection agent dosing devices 20 installed may be one as shown in Figure 8, or multiple. When multiple devices are installed, the leak detection agent dosing devices 20 are separately placed in the outdoor unit 100 and the indoor unit 200. In other words, the leak detection agent dosing devices 20 are placed in both the outdoor unit 100 and the indoor unit 200. This makes the refrigeration system 50 a system that can more quickly identify the location of a refrigerant leak.

The configuration of the leak detection agent dosing device 20 is not particularly limited, and a conventional configuration such as that disclosed in Japanese Patent No. 6742519 can be adopted. Below, we will briefly explain the leak detection agent dosing device 20 that adopts this conventional technology.

The leak detection agent injection device 20 includes a container 20a in which the leak detection agent 23 is stored, two connection pipes 21 and 22 that connect the container 20a to the refrigerant pipe 10 of the refrigerant circuit A, and two control valves (not shown) provided on each of the two connection pipes 21 and 22. A pressure difference is provided between the inlet 21a, which is the connection port between the connection pipe 21 and the refrigerant pipe 10, and the outlet 22a, which is the connection port between the connection pipe 22 and the refrigerant pipe 10. This pressure difference causes the refrigerant in the refrigerant pipe 10 to flow into the container 20a of the leak detection agent injection device. The control valve is closed under normal conditions when there is no refrigerant leakage, and the leak detection agent 23 is not injected into the refrigerant circuit A. When the control valve is opened, the refrigerant flowing through the refrigerant pipe 10 flows into the container 20a due to the pressure difference. Then, the refrigerant mixed with the leak detection agent 23 flows out of the container 20a and into the refrigerant pipe 10. In addition, the refrigerant contains oil to maintain the lubrication of the sliding parts in the compressor 1, and the leak detection agent 23 becomes mixed into the refrigerant containing the oil.

Under normal conditions when there is no refrigerant leakage, the supply control device 33 does not supply the leak detection agent 23 from the leak detection agent supply device 20 to the refrigerant circuit A. When a refrigerant leakage is detected, the supply control device 33 supplies the leak detection agent 23 from the leak detection agent supply device 20 to the refrigerant circuit A.

Fig. 9 is a flowchart showing the operation of the refrigeration system according to the embodiment 2. The following will mainly describe the differences between the flowchart in Fig. 9 and the flowchart in Fig. 5 of the embodiment 1.
After issuing a refrigerant leak alarm in step S3, the control device 30 starts the pump-down operation in step S4, starts the air cleaning device operation in step S5, and also starts the operation of the leak detection agent dosing device 20 (step S10). Specifically, the control device 30 outputs a signal to drive the leak detection agent dosing device 20 to the dosing control device 33, and the dosing control device 33 outputs an ON signal to the control valve of the leak detection agent dosing device 20. This opens the control valve of the leak detection agent dosing device 20, and the leak detection agent 23 is dosed from the leak detection agent dosing device 20 into the refrigerant circuit A.

Refrigerant circuit A is performing pump-down operation, and since refrigerant is circulating in refrigerant circuit A, the leak detection agent 23 introduced into refrigerant circuit A from the leak detection agent introduction device 20 also circulates, and the leak detection agent 23 leaks from the location of the refrigerant leak. The inspector identifies the location of the refrigerant leak using an ultraviolet lamp as described above (step S11). After identifying the location of the refrigerant leak, the inspector stops the pump-down operation (step S7a) and repairs the leak (step S8). After the leak has been repaired, the inspector restarts the refrigeration device 300 (step S9).

In the above, an example is described in which the operational controls of steps S4, S5 and S10 are started simultaneously, but this is not limited thereto, and operation may be started in sequence at a preset time interval.

In addition, in step S4, the control device 30 may start pump-down operation after the introduction of the leak detection agent 23 into the refrigerant circuit A has been completed.

In addition, in step S10, the input control device 33 may control the leak detection agent input device 20 so that the leak detection agent 23 is continuously input into the refrigerant circuit A for, for example, several minutes. In step S10, the input control device 33 may control the leak detection agent input device 20 so that the leak detection agent 23 is intermittently input into the refrigerant circuit A at preset time intervals.

In the above, the configuration in which the leak detection agent injection device 20 injects the leak detection agent 23 into the refrigerant circuit A has been described, but the refrigeration system 50 of embodiment 2 may be configured so that the leak detection agent 23 circulates in the refrigerant circuit A, and the method of injecting the leak detection agent 23 into the refrigerant circuit A is not important. For example, when the compressor 1 is shipped, the leak detection agent 23 may be stored in the compressor 1 together with the refrigerant and lubricating oil, and the leak detection agent 23 may circulate in the refrigerant circuit A by operating the compressor 1. In addition, considering the deterioration of the leak detection agent 23 due to the continued circulation of the leak detection agent 23 in the refrigerant circuit A, it is preferable that the refrigeration system 50 is provided with the leak detection agent injection device 20 and the leak detection agent 23 is injected into the refrigerant circuit A when a refrigerant leak is detected.

The refrigeration system 50 of embodiment 2 has the same effects as embodiment 1, and also has the following effects by circulating the leak detection agent 23 in the refrigerant circuit A. In the event of a refrigerant leak from the refrigerant circuit A, the refrigeration system 50 can identify the location of the refrigerant leak by the leak detection agent 23 leaking out from the location of the refrigerant leak. This allows the refrigeration system 50 to further improve safety.

In addition, the refrigeration system 50 is equipped with a leak detection agent injection device 20, which injects the leak detection agent 23 into the refrigerant circuit A when a refrigerant leak is detected, so that the deterioration of the function of the leak detection agent 23 can be suppressed compared to a configuration in which the leak detection agent 23 is constantly circulating within the refrigerant circuit A. As a result, the refrigeration system 50 can stably detect the location of a refrigerant leak over a long period of time. In addition, if the function of the leak detection agent 23 deteriorates, it may take time to identify the location of the refrigerant leak, but in this embodiment 2, the deterioration of the function of the leak detection agent 23 can be suppressed, making it possible to detect the location of the refrigerant leak early.

In addition, when a leak detection agent injection device 20 is installed in each of the outdoor unit 100 and the indoor unit 200 in the refrigeration system 50, the location of the refrigerant leak can be discovered more quickly.

LIST OF REFERENCE NUMERALS 1 Compressor, 2 Oil separator, 3 Condenser, 3a Fan, 4 Receiver, 5 Subcooling heat exchanger, 5a Pressure reducing device, 5b Injection piping, 6 Dryer, 7 Pressure reducing device, 8 Evaporator, 8a Fan, 9 Accumulator, 10 Refrigerant piping, 12 Liquid extension piping, 13 Gas extension piping, 20 Leak detection agent injection device, 20a Container, 21 Connection piping, 21a Inlet, 22 Connection piping, 22a Outlet, 23 Leak detection agent, 30 Control device, 31 Detection device, 32 Cleaning control device, 33 Input control device, 50 Refrigeration system, 60 Outdoor space, 70 Indoor space, 100 Outdoor unit, 100A Outdoor unit, 200 Indoor unit, 300 Refrigeration device, 400 Air cleaning device, 401 Filter, 402 Fan motor, 403 Fan, 500 Compression unit, 600 outdoor unit, 700 indoor unit, 800 air conditioner, A refrigerant circuit, TH1 first temperature sensor, TH2 second temperature sensor, TH3 third temperature sensor, TH4 fourth temperature sensor.

Claims (15)

a refrigeration device having a refrigerant circuit including a compressor, a condenser, a pressure reducing device, and an evaporator, the compressor, the condenser, the ... refrigerant circuit being connected by a refrigerant pipe so that a flammable refrigerant circulates;
a refrigerant leakage detection device that detects a refrigerant leakage from the refrigerant circuit of the refrigeration device;
A refrigeration system comprising an air cleaning device which starts operating only when a refrigerant leak is detected by the refrigerant leak detection device and does not operate constantly, and which removes the flammable refrigerant from the air taken in. The refrigeration system of claim 1, wherein the air cleaning device is equipped with a filter having an adsorbent that adsorbs the flammable refrigerant. The refrigeration system according to claim 1 or 2, wherein the air cleaning device is equipped with a filter having a decomposition catalyst that chemically reacts with the flammable refrigerant and decomposes the flammable refrigerant to make it non-combustible. The refrigeration system according to any one of claims 1 to 3, wherein the air cleaning device is equipped with a fan that takes in air from the outside, and the fan operates at full speed when a refrigerant leak is detected. The refrigeration device is an air conditioner that adjusts the temperature of air taken in from the outside by passing the air through the condenser or the evaporator, and blows the temperature-adjusted air to the outside,
The refrigeration system according to any one of claims 1 to 4, wherein the air conditioner is equipped with the air cleaning device. The refrigeration system according to any one of claims 1 to 5, wherein the air cleaning device is disposed at a height equal to or lower than the position of the refrigeration device. A receiver provided in the refrigerant circuit;
a control device;
The refrigeration system according to any one of claims 1 to 6, wherein the control device performs a pump-down operation to recover the flammable refrigerant in the receiver when a refrigerant leak is detected by the refrigerant leak detection device. The refrigeration system according to any one of claims 1 to 7, comprising a leak detection agent circulating within the refrigerant circuit. The refrigeration system of claim 8 further comprising a leak detection agent injection device that injects the leak detection agent into the refrigerant circuit when a refrigerant leak is detected by the refrigerant leak detection device. The refrigeration system according to claim 9, which is dependent on claim 7, wherein, when a refrigerant leak is detected by the refrigerant leak detection device, the air cleaning device starts operating, the pump-down operation starts, and the leak detection agent is injected into the refrigerant circuit from the leak detection agent injection device simultaneously. The refrigerant circuit includes an oil separator that separates oil contained in the refrigerant discharged from the compressor,
11. The refrigeration system according to claim 9, wherein the leakage detection agent injection device is connected to the refrigerant piping downstream of the oil separator. The outdoor unit and the indoor unit are connected by an extension pipe to form the refrigerant circuit,
The refrigeration system according to any one of claims 9 to 11, wherein the leak detection agent dosing device is provided in each of the outdoor unit and the indoor unit. The refrigeration system according to any one of claims 8 to 12, wherein the leak detection agent is a fluorescent agent, a coloring agent, an agent that emits an odor, or an agent that emits bubbles in the air. The refrigerant circuit includes a subcooling heat exchanger between the condenser and the evaporator,
The refrigeration system according to any one of claims 1 to 13, wherein the refrigerant leak detection device detects the presence of a refrigerant leak when a subcooling efficiency, which is a value obtained by dividing the degree of subcooling of the subcooling heat exchanger by a calculated temperature obtained by subtracting the outside air temperature from the inlet temperature of the subcooling heat exchanger, is continuously less than a predetermined judgment threshold for a predetermined set period. A first temperature sensor is provided at any position in a flow path from an outlet side of the condenser to an inlet side of the subcooling heat exchanger, and detects a temperature of the refrigerant;
A second temperature sensor is provided at any position in a flow path from an outlet side of the subcooling heat exchanger to an inlet side of the pressure reducing device, and detects a temperature of the refrigerant;
a third temperature sensor that detects an outside air temperature, or a fourth temperature sensor that detects a temperature of a refrigerant that is reduced in pressure and cooled and that is injected into the compressor by a part of the refrigerant that has flowed out of the condenser;
The refrigerant leak detection device determines the degree of subcooling as a temperature difference between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor,
The refrigeration system according to claim 14 , wherein the calculated temperature is a temperature difference between the temperature measured by the first temperature sensor and the temperature measured by the third temperature sensor, or a temperature difference between the temperature measured by the first temperature sensor and the temperature measured by the fourth temperature sensor.

Images