JP5717584B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus. In particular, the present invention relates to processing of a refrigerant having a carbon double bond in a molecular structure in a binary refrigeration apparatus.

  In recent years, from the viewpoint of preventing ozone layer destruction, a transition to a refrigerant not containing chlorine has been performed as a refrigerant to be sealed in a refrigeration cycle apparatus. However, since these HFC refrigerants that do not contain chlorine (for example, R410A, R404A, etc.) have a relatively high global warming potential, measures to prevent refrigerant leakage are taken so that the refrigerant does not leak out of the refrigeration system, or when the equipment is discarded. A refrigerant recovery obligation is imposed. However, since the recovery rate is insufficient and there are refrigerant leaks during use, further transition to a refrigerant having a low global warming potential (GWP) value is desired. As a refrigerant having a small GWP value, for example, natural refrigerants such as carbon dioxide, HFO (olefinic fluorine compound) refrigerants (hereinafter referred to as HFO refrigerants) such as HFO-1234yf (hydrofluoroolefin), and the like are being studied. .

  For example, conventionally, in a refrigeration apparatus using an HFO refrigerant, the refrigerant accommodating means for accommodating the refrigerant, the additional reactant supply means for supplying the substance contributing to the addition reaction in the refrigerant accommodating means, and the refrigerant accommodating means are accommodated in the refrigerant accommodating means. There has been proposed one provided with ultraviolet irradiation means for making the refrigerant non-flammable by irradiating the refrigerant (for example, see Patent Document 1).

JP 2009-297341 A (Page 9, FIG. 3)

  For example, in the current refrigerant recovery device or the like, when recovering the refrigerant, an external ignition source (for example, a spark at a relay contact portion of an adjacent device) may cause a fire or an explosion. Here, for example, a refrigerant such as an HFO refrigerant having a carbon double bond in its molecular structure is a flammable refrigerant. When leakage of the HFO refrigerant in the refrigerant circuit occurs, most of the HFO refrigerant enclosed in the refrigerant circuit is released to the outside, so the HFO refrigerant is filled over a wide area and safety cannot be maintained. There is a possibility of becoming an environment. For this reason, when using an HFO refrigerant, it is necessary to ensure safety so that no fire or the like occurs even if a refrigerant leak occurs during recovery, an accident, or the like.

  Here, the HFO refrigerant has a molecular structure having a carbon double bond. In general, functional groups such as carbon-carbon double bonds and triple bonds, in other words, alkenes and alkynes (unsaturated hydrocarbons) are characterized by the addition reaction of various molecules. For this reason, a refrigerant having a double bond is easier to cleave the double bond part than a conventional refrigerant having no double bond, and the functional group easily reacts with other substances and has chemical stability. It has extremely inferior characteristics. In particular, the refrigerant is easily decomposed by reaction with air or moisture mixed as contamination (contamination) in the refrigerant circuit. In the apparatus disclosed in Patent Document 1, when an HFO refrigerant is irradiated with ultraviolet rays, an addition reaction that cuts the carbon double bond portion of the HFO refrigerant occurs, so that a carboxylic acid structure (R-COOH) having oxygen molecules bonded thereto is formed. Since it is produced, the HFO refrigerant is made to be a nonflammable substance.

  However, since the apparatus of Patent Document 1 is provided with a refrigerant storage means, an addition reactant supply means, an ultraviolet irradiation means, and the like, it becomes a large-scale apparatus. For this reason, it is difficult to put it to practical use because it increases costs.

  The present invention relates to a refrigeration cycle apparatus that uses a refrigerant having a carbon double bond in its molecular structure, such as an HFO refrigerant, in a refrigerant circulation circuit. A refrigeration cycle apparatus capable of performing the above is provided.

In the refrigeration cycle apparatus according to the present invention, a compressor, a condenser, a throttling device, and an evaporator are connected by piping, one of which contains a refrigerant having a molecular structure of a carbon double bond, and the other is a refrigerant containing carbon dioxide. A two- way refrigeration cycle apparatus having two refrigerant circulation circuits that enclose the refrigerant, and a communication pipe that connects the two refrigerant circulation circuits so that they can communicate with each other, and the passage of refrigerant containing carbon dioxide in the communication pipe is controlled For opening and closing.

  According to the refrigeration cycle apparatus of the present invention, a refrigerant having a molecular structure of a flammable carbon double bond is provided as a refrigerant in one refrigerant circulation circuit, which includes a communication pipe that connects two refrigerant circulation circuits and an opening / closing means. When used, the carbon dioxide refrigerant used in the other refrigerant circulation circuit can be mixed through the communication pipe to make it nonflammable. For example, at the time of service, refrigerant recovery, etc. Workers can work safely.

It is a figure which shows the structure of the refrigerating-cycle apparatus in Embodiment 1 of this invention. It is a figure which shows the structure of the refrigerating-cycle apparatus in Embodiment 2 of this invention. It is a figure which shows the structure of the refrigerating-cycle apparatus in Embodiment 3 of this invention. It is a figure which shows the structure of the refrigerating-cycle apparatus in Embodiment 4 of this invention. It is a figure which shows the structure of the refrigerating-cycle apparatus in Embodiment 5 of this invention.

Embodiment 1 FIG.
1 is a diagram showing a configuration of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. Here, a binary refrigeration apparatus will be described as an example of a refrigeration cycle apparatus. As shown in FIG. 1, the binary refrigeration apparatus in the present embodiment includes a high-temperature side circulation circuit 10 and a low-temperature side circulation circuit 20, and constitutes a refrigerant circulation circuit that circulates refrigerant independently of each other. In order to make the two refrigerant circulation circuits into a multi-stage configuration, a cascade condenser (refrigerant) in which the high-temperature side evaporator 14 and the low-temperature side condenser 22 are coupled so as to be able to exchange heat between the refrigerants passing therethrough. An intermediate heat exchanger) 30 is provided. Moreover, the connection part 40 for connecting the high temperature side circulation circuit 10 and the inside of the low temperature side circulation circuit 20 is provided. And it has the control means 50 which performs operation control of the whole binary refrigeration apparatus. Here, the levels of temperature and pressure described below are not particularly determined in relation to absolute values, but are relatively determined in the state and operation of the system, apparatus, etc. To do.

  In FIG. 1, a high temperature side circulation circuit 10 is a refrigerant circulation circuit in which a high temperature side compressor 11, a high temperature side condenser 12, a high temperature side expansion device 13, and a high temperature side evaporator 14 are connected in series by a refrigerant pipe. It is composed. On the other hand, the low temperature side circulation circuit 20 is a refrigerant circulation circuit in which a low temperature side compressor 21, a low temperature side condenser 22, a first low temperature side expansion device 23, and a low temperature side evaporator 24 are connected in series by a refrigerant pipe. Is configured.

Here, a refrigerant (HFO refrigerant) having a carbon double bond in a molecular structure, such as HFO-1234yf, is used as a refrigerant circulating in the high temperature side circulation circuit (hereinafter referred to as a high temperature side refrigerant). Since such a refrigerant generally has a low GWP (10 or less), it will be useful as a refrigerant for performing cooling by a refrigeration cycle apparatus in the future. In addition, a refrigerant (carbon dioxide refrigerant) containing carbon dioxide (CO ₂ ) is used as a refrigerant circulating in the low temperature side circulation circuit (hereinafter referred to as a low temperature side refrigerant).

  The high temperature side compressor 11 of the high temperature side circulation circuit 10 sucks the high temperature side refrigerant, compresses it, and discharges it in a high temperature / high pressure state. Here, for example, it may be configured by a compressor of a type that can control the number of revolutions by an inverter circuit or the like and adjust the discharge amount of the high-temperature side refrigerant. The high temperature side condenser 12 performs heat exchange between air, water and the like supplied from, for example, a blower, a pump, or the like (not shown) and the high temperature side refrigerant to condense and liquefy the high temperature side refrigerant.

  The high temperature side expansion device 13 such as a pressure reducing valve or an expansion valve expands the high temperature side refrigerant by reducing the pressure. For example, it is optimally configured by a flow rate control means such as an electronic expansion valve, but it may also be configured by a refrigerant flow rate control means such as a capillary tube or a temperature-sensitive expansion valve. The high temperature side evaporator 14 evaporates the high temperature side refrigerant by heat exchange. For example, here, it is assumed that the heat transfer tube or the like through which the high-temperature side refrigerant passes in the cascade capacitor 30 serves as the high-temperature side evaporator 14 and performs heat exchange with the low-temperature side refrigerant.

  On the other hand, the low temperature side compressor 21 of the low temperature side circulation circuit 20 sucks the low temperature side refrigerant, compresses the refrigerant, and discharges it in a high temperature / high pressure state. The low temperature side compressor 21 may be configured by a compressor of a type that has an inverter circuit or the like and can adjust the discharge amount of the low temperature side refrigerant. The low temperature side condenser 22 condenses and liquefies the low temperature side refrigerant by heat exchange. For example, here, it is assumed that the heat transfer tube or the like through which the low-temperature side refrigerant passes in the cascade capacitor 30 serves as the low-temperature side condenser 22 and performs heat exchange with the high-temperature side refrigerant.

  The low temperature side expansion device 23 such as a pressure reducing valve or an expansion valve decompresses the low temperature side refrigerant to expand it. For example, it is optimal to configure with flow rate control means such as an electronic expansion valve, but it may be configured with refrigerant flow rate control means such as capillaries. Here, it is assumed that the low temperature side throttle device 23 is constituted by a flow rate control means for adjusting the opening degree based on an instruction from the control means 50. For example, in the case where the low temperature side throttle device 23 is a refrigerant flow rate adjusting means that cannot adjust the opening, in order to minimize the throttle function and reduce pressure loss, for example, bypass piping (in parallel with the low temperature side throttle device 23 ( (Not shown) may be provided. And when a refrigerant | coolant flow volume adjustment means is not required, you may comprise so that it can switch so that a refrigerant | coolant may be flowed to bypass piping.

  The low temperature side evaporator 24 performs heat exchange between air, brine, and the like supplied from, for example, a blower, a pump, or the like (not shown) and the low temperature side refrigerant to evaporate the low temperature side refrigerant. The object to be cooled is cooled directly or indirectly by heat exchange with the low-temperature side refrigerant.

  The cascade condenser 30 is a refrigerant heat exchanger that has the functions of the high-temperature side evaporator 14 and the low-temperature side condenser 22 described above and enables heat exchange between the high-temperature side refrigerant and the low-temperature side refrigerant. For example, it is composed of a plate heat exchanger, a double pipe heat exchanger or the like. By making the high temperature side circulation circuit and the low temperature side circulation circuit into a multistage configuration via the cascade capacitor 30 and performing heat exchange between the refrigerants, independent refrigerant circulation circuits can be linked.

  The connection part 40 of this Embodiment connects the inside of the low temperature side circulation circuit 20 and the inside of the high temperature side circulation circuit 10 so that communication is possible. The connection unit 40 includes an operation valve 41 serving as an opening / closing means, a first connection pipe 42 serving as a communication pipe, and a second connection pipe 43. The operation valve 41 is a valve that opens and closes based on an instruction from the control means 50. By opening the operation valve 41, the first connection pipe 42 connecting the operation valve 41 and the low temperature side circulation circuit 20 and the second connection pipe 43 connecting the operation valve 41 and the high temperature side circulation circuit 10 are connected. Each refrigerant circulation circuit can be communicated. Here, the operation valve 41 may be capable of adjusting the opening degree.

  Here, one end of the first connection pipe 42 is connected to the high temperature side circulation circuit 10 between the refrigerant outflow side of the high temperature side condenser 12 and the high temperature side expansion device 13. Further, one end of the second connection pipe 43 is connected to the low temperature side circulation circuit 20 between the refrigerant outflow side of the low temperature side condenser 22 and the low temperature side expansion device 23. The low temperature side refrigerant is a carbon dioxide refrigerant, and the high temperature side refrigerant is an HFO refrigerant. For this reason, the pressure (for example, the pressure on the high pressure side) is lower in the high temperature side circulation circuit 10 than in the low temperature side circulation circuit 20. Therefore, when the operation valve 41 is opened, the carbon dioxide refrigerant flows into the high temperature side circulation circuit 10.

  Moreover, the control means 50 monitors the state of the high temperature side circulation circuit 10 and the low temperature side circulation circuit 20, and controls operations such as a cooling operation in the binary refrigeration apparatus. For example, operations of the high temperature side compressor 11, the high temperature side expansion device 13, the low temperature side compressor 21, the low temperature side expansion device 23, and the like are controlled. In the present embodiment, for example, the opening / closing of the operation valve 41 is controlled based on the pressure (condensation pressure) related to the detection of the high pressure sensor 51 installed between the high temperature side compressor 11 and the high temperature side condenser 12.

  The binary refrigeration apparatus of the present embodiment has a connection portion 40 that connects the inside of the low-temperature side circulation circuit 20 and the inside of the high-temperature side circulation circuit 10 so that they can communicate with each other, and the high-temperature side refrigerant is HFO refrigerant and the low-temperature side refrigerant is carbon dioxide. Use carbon refrigerant. The carbon dioxide refrigerant (low temperature side refrigerant) sealed in the low temperature side circulation circuit 20 is caused to flow into the high temperature side circulation circuit 10 to make the HFO refrigerant (high temperature side refrigerant) incombustible, and then the high temperature side circulation circuit 10. Service, refrigerant recovery, etc., prevent ignition of HFO refrigerant, etc., and ensure safety.

  Next, operation | movement of each component apparatus at the time of the cooling operation of a binary refrigeration apparatus is demonstrated based on the flow of the refrigerant | coolant which circulates through each refrigerant | coolant circulation circuit. First, the operation during the cooling operation of the high-temperature side circulation circuit 10 will be described. The high temperature side compressor 11 sucks the high temperature side refrigerant, compresses it, and discharges it in a high temperature / high pressure state. The discharged refrigerant flows into the high temperature side condenser 12. The high temperature side condenser 12 performs heat exchange between air, water, and the like supplied from a blower, a pump, or the like (not shown) and the high temperature side refrigerant to condense and liquefy the high temperature side refrigerant. The condensed high-temperature side refrigerant passes through the high-temperature side expansion device 13. The high temperature side expansion device 13 depressurizes the condensed liquid refrigerant passing therethrough. The decompressed refrigerant flows into the high temperature side evaporator 14 (cascade capacitor 30). The high temperature side evaporator 14 evaporates and gasifies the high temperature side refrigerant by heat exchange with the low temperature side refrigerant. The high temperature side compressor 11 sucks and discharges the high temperature side refrigerant that has been vaporized and gasified.

  The low temperature side compressor 21 sucks the low temperature side refrigerant, compresses the refrigerant, and discharges it in a high temperature / high pressure state. The discharged refrigerant flows into the low temperature side condenser 22 (cascade capacitor 30). The low temperature side condenser 22 condenses and liquefies the low temperature side refrigerant by heat exchange with the high temperature side refrigerant. The condensed and liquefied low temperature side refrigerant passes through the low temperature side expansion device 23. The low temperature side expansion device 23 depressurizes the condensed low temperature side refrigerant. The decompressed low-temperature side refrigerant flows into the low-temperature side evaporator 24. The low temperature side evaporator 24 performs heat exchange between the object to be cooled and the low temperature side refrigerant, and evaporates the low temperature side refrigerant. At this time, the object to be cooled is cooled directly or indirectly. The low-temperature side refrigerant 21 that has flowed out of the low-temperature side evaporator 24 is sucked and discharged by the low-temperature side compressor 21.

  Next, operations during service, refrigerant recovery, and the like will be described. For example, the normal cooling operation is stopped at the time of service or the like. Moreover, it is desirable to maximize the opening degree at least for the high temperature side expansion device 13. An operator or the like instructs the control means 50 to open the operation valve 41 via an input means (not shown). The control means 50 opens the operation valve 41. As described above, when the operation valve 41 is opened, the low temperature side refrigerant flows from the low temperature side circulation circuit 20 side to the high temperature side circulation circuit 10 side. The pressure in the high-temperature side circulation circuit 10 into which the low-temperature side refrigerant has flowed rises.

  And if the control means 50 judges that the pressure which the detection of the high pressure sensor 51 became predetermined pressure, it will close the operation valve 41. FIG. If carbon dioxide is mixed in the HFO refrigerant to some extent, it becomes nonflammable. In the present embodiment, the mixing ratio is determined based on the pressure associated with detection by the high pressure sensor 51. Here, in some cases, the high temperature side compressor 11 may be driven to promote mixing. For example, the HFO refrigerant is charged into the high temperature side circulation circuit 10 after the work. Further, the low temperature side circulation circuit 20 is supplemented with carbon dioxide refrigerant.

  As described above, according to the refrigeration cycle apparatus of the first embodiment, the HFO refrigerant that is flammable as the high-temperature side refrigerant in the high-temperature side circulation circuit 10 is connected via the connection portion 40 at the time of service, refrigerant recovery, and the like. Since the carbon dioxide refrigerant which is the low temperature side refrigerant of the low temperature side circulation circuit 20 can be mixed and made nonflammable, for example, an operator can safely perform services such as service. At this time, since the control means 50 closes the operation valve 41 when a predetermined pressure is reached based on the pressure detected by the high pressure sensor 51, the required amount of carbon dioxide refrigerant is automatically supplied to the high temperature side circulation circuit. 10 can be allowed to flow. In addition, a refrigeration cycle apparatus having a low GWP can be provided.

Embodiment 2. FIG.
FIG. 2 is a diagram showing the configuration of the refrigeration cycle apparatus according to Embodiment 2 of the present invention. In FIG. 2, devices denoted by the same reference numerals as those in FIG. 1 perform the same operations and the like as the devices described in the first embodiment. For example, when the carbon dioxide refrigerant is allowed to flow into the high temperature side circulation circuit 10, the connection throttle device 44 can reduce the carbon dioxide refrigerant and allow the carbon dioxide refrigerant to flow in while adjusting the refrigerant amount. . Here, it is assumed that the pressure can be adjusted by controlling the opening, but a capillary tube or the like may be used.

  For example, in general, the pressure in the high-temperature side circulation circuit 10 using the HFO refrigerant as the high-pressure side refrigerant is lower than the pressure in the low-temperature side circuit 20 using the carbon dioxide refrigerant as the low-pressure side refrigerant. For example, depending on the circuit scale and the like, if the pressure difference between the high-temperature side circulation circuit 10 and the low-temperature side circulation circuit 20 is large, when the operation valve 41 is opened, a large amount of high-temperature side refrigerant flows and the pressure rapidly increases. To do. In order to cope with such a pressure, the design pressure resistance of the equipment, refrigerant piping, etc. constituting the high-temperature side circulation circuit 10 must be made higher than necessary. Also, it is better to prevent the carbon dioxide refrigerant from solidifying due to the sudden flow into the low pressure environment.

  Therefore, in the present embodiment, the connection part expansion device 44 is provided in the connection part 40 so that the carbon dioxide refrigerant that is the low-temperature side refrigerant is decompressed and flows into the high-temperature side circulation circuit 10. Thereby, without setting the design pressure resistance of the high-temperature side circulation circuit 10 higher than necessary, it is possible to select a pressure-resistant device or the like corresponding to the HFO refrigerant that is the high-temperature side refrigerant, and safely while suppressing the setting cost. The refrigeration cycle apparatus which coped with can be obtained.

Embodiment 3 FIG.
FIG. 3 is a diagram showing the configuration of the refrigeration cycle apparatus according to Embodiment 3 of the present invention. 3, devices having the same reference numerals as those in FIGS. 1 and 2 perform the same operations as the devices described in the first and second embodiments. The liquid receiver (receiver) 15 is a container such as a tank that is provided on the refrigerant outflow side of the high temperature side condenser 12 (between the high temperature side condenser 12 and the high temperature side expansion device 13) and stores the refrigerant. In the present embodiment, the volume of the refrigerant in the high temperature side circulation circuit 10 is increased by the inflow of carbon dioxide refrigerant, which is a low temperature side refrigerant, so that, for example, a liquid refrigerant (liquid refrigerant) flows into the high temperature side compressor 11 ( (Liquid back) etc. should not occur. For this reason, it shall have the volume which can be stored according to the inflow of a carbon dioxide refrigerant.

  As described above, in the third embodiment, the liquid receiver 15 is provided in the high-temperature side circulation circuit 10 so that the liquid refrigerant in the high-temperature side circulation circuit 10 can be stored. By storing the refrigerant in the side circulation circuit 10, for example, liquid back or the like can be prevented, and the operation of the high temperature side circulation circuit 10 can be prevented from being hindered.

Embodiment 4 FIG.
4 is a diagram showing the configuration of a refrigeration cycle apparatus in Embodiment 4 of the present invention. In FIG. 4, the same reference numerals as those in FIG. 1 and the like perform the same operations and the like as the devices described in the first embodiment. The low pressure sensor 52 detects the pressure (low pressure) on the suction side of the high temperature side compressor 11. Moreover, it has the alerting | reporting means 60 which alert | reports visually, aurally, for example with light, a sound, etc. based on the signal from the control means 50. FIG. Here, as for the connection portion 40 of the present embodiment, the operation valve 41 may be used as in the above-described embodiment, but as soon as possible, the valve is opened so that the carbon dioxide refrigerant can flow in. Therefore, here, the electromagnetic valve 45 is used. Furthermore, in this Embodiment, it shall have the air blower 16 for sending air into the high temperature side condenser 12, and encouraging heat exchange.

  In the present embodiment, when it is determined that the leakage of the HFO refrigerant has occurred in the high temperature side circulation circuit 10, the solenoid valve 45 is opened to cause the carbon dioxide refrigerant to flow into the high temperature side circulation circuit 10, and the high temperature side refrigerant is incombustible. To ensure safety.

  Next, processing performed by the control unit 50 will be described. When the control means 50 determines that the pressure related to the detection by the low pressure sensor 52 is equal to or lower than a predetermined pressure, the control means 50 opens the solenoid valve 45 and assumes that the carbon dioxide refrigerant is not flowing, assuming that the refrigerant leakage has occurred in the high temperature side circulation circuit 10. It flows into the high temperature side circulation circuit 10. Then, a signal is sent to the notification means 60 to be notified. Moreover, the leaked refrigerant is diffused by driving the blower 16.

  As described above, according to the binary refrigeration apparatus of the fourth embodiment, when the refrigerant leakage occurs in the high temperature side circulation circuit 10 based on the pressure related to the detection of the low pressure sensor 52, the electromagnetic valve 45 Since the carbon dioxide refrigerant flows into the high-temperature side circulation circuit 10 to make it nonflammable, even if it leaks around the refrigeration apparatus, safety can be achieved without causing ignition. Moreover, since the refrigerant | coolant which leaked can be diffused etc. by driving the air blower 16, further safety can be achieved. Further, since the notification is performed by the notification means 60, further safety can be achieved by promptly informing the refrigerant leakage. In some cases, for example, a signal can be sent from a remote management device or the like.

Embodiment 5 FIG.
FIG. 5 is a diagram showing the configuration of the refrigeration cycle apparatus in the fifth embodiment. In FIG. 5, the same reference numerals as those in FIG. 1 and the like perform the same operations as those in the first embodiment. The service port 70 serving as a communication means is a port that enables communication between the refrigerant circulation circuit and the outside in order to supply and discharge HFO refrigerant, for example. The service port 70 can be connected to, for example, a connecting pipe for discharging the refrigerant. And it becomes possible to make the refrigerant | coolant collection | recovery apparatus 80 grade | etc., Collect | recover the discharged | emitted refrigerant | coolants via a connecting pipe etc. Here, although the service port 70 of this Embodiment was provided between the high temperature side compressor 11 and the high temperature side condenser 12, it does not specifically limit about an installation place.

  Moreover, the refrigerant | coolant collection | recovery apparatus 80 is an apparatus which collect | recovers the refrigerant | coolants after carbon dioxide refrigerant mixing, for example. Here, it is assumed that the refrigerant recovery device 80 of the present embodiment has an explosion-proof specification for protecting people, devices, and the like from explosions and the like. For this reason, further safety can be achieved.

Embodiment 6 FIG.
In the above-described embodiment, the control means 50 operates the opening / closing means such as the operation valve 41 so that it can be automatically opened / closed. However, the control means 50 may be configured by, for example, a valve that is manually opened / closed. In this case, for example, the pressure value related to the detection by the high pressure sensor 51 may be displayed by a display means or the like (not shown), so that the operator can open and close while confirming.

  Further, in the above-described embodiment, the high temperature side refrigerant sealed in the high temperature side circulation circuit 10 is an HFO refrigerant, and the low temperature side refrigerant sealed in the low temperature side circulation circuit 20 is a carbon dioxide refrigerant, but the low temperature side refrigerant is an HFO refrigerant. And the high temperature side refrigerant may be a carbon dioxide refrigerant.

  Although the above-described embodiment has been described with a binary refrigeration apparatus, it can also be applied to a multi-stage refrigeration apparatus having a multi-stage configuration.

  DESCRIPTION OF SYMBOLS 10 High temperature side circulation circuit, 11 High temperature side compressor, 12 High temperature side condenser, 13 High temperature side expansion apparatus, 14 High temperature side evaporator, 15 Liquid receiver, 16 Blower, 20 Low temperature side circulation circuit, 21 Low temperature side compressor, 22 Low-temperature side condenser, 23 Low-temperature side throttle device, 24 Low-temperature side evaporator, 30 Cascade condenser, 40 Connection part, 41 Operation valve, 42 First connection pipe, 43 Second connection pipe, 44 Connection part throttle device, 45 Electromagnetic Valve, 50 control means, 51 high pressure sensor, 52 low pressure sensor, 60 notification means, 70 service port, 80 refrigerant recovery device.

Claims (8)

A compressor, a condenser, a throttling device and an evaporator are connected by piping, one of which is filled with a refrigerant having a molecular structure of carbon double bonds, and the other is filled with two refrigerant circulation circuits which contain a refrigerant containing carbon dioxide. Comprising a dual refrigeration cycle apparatus having
A communication pipe that connects the two refrigerant circulation circuits so that they can communicate with each other;
A refrigerating cycle device comprising: opening and closing means for controlling passage of the refrigerant containing carbon dioxide in the communication pipe.   2. The refrigeration cycle apparatus according to claim 1, further comprising a connection portion expansion device for reducing the pressure of the refrigerant containing carbon dioxide and allowing the refrigerant to pass therethrough.   The liquid receiver is further provided between the condenser and the throttle device of the refrigerant circulation circuit that encloses the refrigerant having the molecular structure of the carbon double bond. Refrigeration cycle equipment. Low pressure detection means for detecting pressure on the suction side of the compressor in the refrigerant circuit that encloses the refrigerant having the molecular structure of the carbon double bond;
Control means for opening the opening / closing means when it is determined that the refrigerant having the molecular structure of the carbon double bond in the refrigerant circuit is leaking based on the pressure related to the detection by the low pressure detecting means. The refrigeration cycle apparatus according to any one of claims 1 to 3. A blower for sending air to the condenser of the refrigerant circuit that encloses the refrigerant having the molecular structure of the carbon double bond;
5. The refrigeration cycle apparatus according to claim 4, wherein when the control unit determines that the refrigerant having the molecular structure of the carbon double bond is leaking, the blower is driven. Further comprising notification means for performing notification based on a signal from the control means;
6. The refrigeration cycle apparatus according to claim 4, wherein when the control unit determines that the refrigerant having the molecular structure of the carbon double bond is leaking, the control unit transmits a signal to the notification unit. A refrigerant refrigeration circuit that encloses the refrigerant having the molecular structure of the carbon double bond is a high-temperature side circulation circuit, and a refrigerant circulation circuit that encloses the refrigerant containing carbon dioxide is a low-temperature side circulation circuit to constitute a dual refrigeration cycle apparatus And
A cascade capacitor configured by the evaporator of the high-temperature side circulation circuit and the condenser of the low-temperature side circulation circuit, and performing heat exchange between the refrigerant of the high-temperature side circulation circuit and the refrigerant of the low-temperature side circulation circuit The refrigeration cycle apparatus according to any one of claims 1 to 6, further comprising:   The refrigeration cycle apparatus according to any one of claims 1 to 7, further comprising communication means that allows communication between the explosion-proof refrigerant recovery apparatus and the refrigerant circulation circuit.

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