Refrigeration device

Abstract

In a refrigeration device (R1), a first refrigeration cycle including compression (14) and circulating a first working medium is configured as an outdoor unit (10). In a second refrigeration cycle including a refrigerant pump and circulating a second working medium, at least an indoor heat exchanger (22) and a second pipe (21) are configured as indoor units (20). A relay heat exchanger (32), which exchanges heat between these refrigeration cycles, serves as an independent relay unit (30) together with at least the refrigerant pump (34). The first working medium uses at least a flammable refrigerant as a refrigerant component, and the second working medium uses at least a fluoroolefin as a refrigerant component. As a result, even when a flammable refrigerant or a fluoroolefin is used as a refrigerant component, a good operation of a refrigeration cycle can be performed in a refrigeration device, and existing refrigerant piping can also be used.

Description

Technical Field

[0001] The present invention relates to a refrigeration apparatus using a refrigeration cycle working medium containing fluoroolefin, and more particularly to a refrigeration apparatus capable of satisfactorily avoiding the influence of a disproportionation reaction of fluoroolefin. Background Art

[0002] The working medium for the refrigeration cycle is usually composed of a refrigerant and a refrigeration oil (lubricating oil stored in a sealed compressor). HCFC (hydrochlorofluorocarbon) was previously used as a refrigerant, but HCFC has a great impact on the destruction of the ozone layer. Therefore, in recent years, HFC (hydrofluorocarbon) with an ozone depletion potential (ODP) of 0 is used. Representative examples include difluoromethane (HFC32, R32).

[0003] However, HFC, which is stable as a working medium for a refrigeration cycle, has a long atmospheric lifetime and thus a large global warming potential (GWP). Therefore, the use of saturated hydrocarbons (HC) or fluoroolefins having a lower GWP has recently been proposed.

[0004] As saturated hydrocarbons (HC), butane (R600), isobutane (2-methylpropane, R600a), propane (R290), etc. can be cited. These HCs have an ODP of 0 and a small GWP, but are flammable. Therefore, in a refrigeration cycle using a working medium with HC as a refrigerant component, countermeasures against flammability are required, such as taking adequate anti-leakage measures in the indoor part of the refrigeration cycle.

[0005] Among fluoroolefins, hydrofluoroolefins (HFO) have attracted attention as refrigerant components in recent years. A representative HFO is 1,1,2-trifluoroethylene (HFO1123). HFO1123 has a low GWP and high cooling capacity, and has performance close to that of R32, which is currently widely used.

[0006] However, it is also known that fluoroolefins such as HFO are easily chemically decomposed and have low stability, and thus are prone to undergo a self-polymerization reaction called a disproportionation reaction (hereinafter referred to as a disproportionation reaction). It is also known that the disproportionation reaction is accompanied by a large amount of heat release, so the reaction proceeds in a chain reaction, generating a large amount of coal. Therefore, in a refrigeration cycle using fluoroolefins as a refrigerant component, a countermeasure against the disproportionation reaction is required.

[0007] However, in the field of refrigeration devices, when replacing an existing working medium with a working medium having a lower GWP, it is particularly desirable to use refrigerant pipes already installed indoors (existing refrigerant pipes) as much as possible without changing the working medium.

[0008] The working medium for the refrigeration cycle may also contain a refrigerant component and a refrigeration oil for the compressor. Therefore, for example, when the refrigerant component is replaced from HCFC to HFC with a lower GWP, the refrigeration oil (or its compound, etc.) when the HCFC is used remains in the refrigerant piping.

[0009] When the refrigeration oil or the like remaining in the refrigerant piping is mixed into the refrigeration cycle of the replaced HFC, it is possible to affect the operation of the compressor or expansion mechanism etc. constituting the refrigeration cycle. In this case, the refrigerant piping needs to be replaced as a whole or fully cleaned, so it is impossible to meet the expectation of using the existing refrigerant piping as it is as much as possible.

[0010] Therefore, various refrigeration devices that meet such needs have been proposed. For example, Patent Document 1 discloses a refrigeration device with the following structure: a heat source side refrigerant circuit (refrigeration cycle on the heat source side) includes a compressor, but a utilization side refrigerant circuit (refrigeration cycle on the utilization side) does not include a compressor but includes a refrigerant pump, and each refrigerant circuit is connected via a heat exchanger.

[0011] According to such a configuration, since the user-side refrigerant circuit does not include a compressor, it is possible to avoid refrigeration oil and the like from remaining in the user-side refrigerant piping. As a result, the existing refrigerant piping can be used as it is as much as possible.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: Japanese Patent Application Publication No. 2000-234813 Summary of the invention

[0015] Technical problem to be solved by the invention

[0016] As described above, in response to the recent demand for lower GWP, the refrigerant components used in refrigeration cycles have shifted from HCFC to HFC, and more recently from HFC to HC or fluoroolefins (HFO, etc.). However, HC requires countermeasures against flammability, and fluoroolefins require countermeasures against disproportionation reactions.

[0017] The refrigeration device disclosed in Patent Document 1 is based on the premise that the refrigerant component is replaced from HCFC to HFC. Therefore, there is no research on measures when the refrigerant component is replaced with a flammable refrigerant (HC, etc.) or a fluoroolefin.

[0018] The present invention has been made to solve such a problem, and an object of the present invention is to provide a refrigeration device that can perform a good refrigeration cycle even when a flammable refrigerant or a fluoroolefin is used as a refrigerant component and can utilize existing refrigerant piping.

[0019] Technical solutions to solve problems

[0020] In order to solve the above-mentioned problems, the refrigeration device of the present invention includes: a first refrigeration cycle, which has an outdoor heat exchanger, a compressor, an expansion mechanism and a first pipe connecting them to circulate a first working medium; a second refrigeration cycle, which includes an indoor heat exchanger, a refrigerant pump and a second pipe connecting them to circulate a second working medium; and a relay heat exchanger, which is located between the above-mentioned first refrigeration cycle and the above-mentioned second refrigeration cycle and performs heat exchange between them, the above-mentioned first refrigeration cycle is constituted as an outdoor unit arranged outdoors, and in the above-mentioned second refrigeration cycle, at least the above-mentioned indoor heat exchanger and the above-mentioned second pipe are constituted as indoor units arranged indoors, and at least the above-mentioned relay heat exchanger and the above-mentioned refrigerant pump are constituted as relay units independent of the above-mentioned outdoor unit and the above-mentioned indoor unit, at least a flammable refrigerant is used as a refrigerant component in the above-mentioned first working medium, and at least a fluoroolefin is used as a refrigerant component in the above-mentioned second working medium.

[0021] According to the above structure, an independent relay unit is inserted between the outdoor unit including the first refrigeration cycle and the indoor unit as a part of the second refrigeration cycle. The second refrigeration cycle includes a refrigerant pump but does not include a compressor. Since the refrigerant pump does not use refrigeration oil, it is possible to avoid refrigeration oil and the like from remaining in the second piping of the indoor unit as a part of the second refrigeration cycle. As a result, the refrigerant piping already installed in the indoor unit can be used roughly as it is.

[0022] Furthermore, in the first refrigeration cycle including the compressor, a first working medium having a flammable refrigerant as a main component is used, but the first refrigeration cycle is constituted as an outdoor unit. On the other hand, in the second refrigeration cycle, a second working medium having a fluoroolefin as a main component is used as a refrigerant component, but the second refrigeration cycle is constituted as an indoor unit and a relay unit. Thus, the first refrigeration cycle using the flammable refrigerant is clearly separated from the indoor unit via the relay unit. Therefore, the influence of the use of the flammable refrigerant can be further reduced by inserting the relay unit.

[0023] Furthermore, the first working medium circulating in the first refrigeration cycle including the compressor does not need to use fluoroolefins. Fluoroolefins are prone to undergo a disproportionation reaction under the conditions of high temperature and high pressure in the compressor, but if fluoroolefins are not used as the refrigerant component of the first working medium, there is no need to implement countermeasures against the disproportionation reaction in the first refrigeration cycle.

[0024] On the other hand, the second working medium containing fluoroolefin as the main component circulates in the second refrigeration cycle that does not include a compressor. In the refrigerant pump, the second working medium does not become high temperature and high pressure when it is sent out, so it can be considered that the disproportionation reaction of fluoroolefin does not substantially occur. Therefore, it is not necessary to implement a countermeasure against the disproportionation reaction in the second refrigeration cycle.

[0025] As a result, even when a flammable refrigerant or a fluoroolefin is used as a refrigerant component, a favorable operation of the refrigeration cycle can be achieved, and existing refrigerant piping can be utilized on the indoor side.

[0026] The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

[0027] Effects of the Invention

[0028] The present invention has the above-described configuration and has the effect of providing a refrigeration apparatus that can perform a good refrigeration cycle even when a flammable refrigerant or a fluoroolefin is used as a refrigerant component and can utilize existing refrigerant piping. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic circuit diagram showing a typical configuration example of the refrigeration device according to Embodiment 1 of the present invention.

[0030] Figure 2 This is a schematic circuit diagram showing a typical configuration example of a refrigeration device according to Embodiment 2 of the present invention.

[0031] Figure 3 This is a schematic circuit diagram showing a typical configuration example of a refrigeration device according to Embodiment 3 of the present invention.

[0032] Figure 4 This is a schematic circuit diagram showing a typical configuration example of a refrigeration device according to Embodiment 4 of the present invention.

[0033] Figure 5 This is a schematic circuit diagram showing a typical configuration example of a refrigeration device according to Embodiment 5 of the present invention. DETAILED DESCRIPTION

[0034] The refrigeration device of the present invention includes: a first refrigeration cycle, which has an outdoor heat exchanger, a compressor, an expansion mechanism and a first pipe connecting them to circulate a first working medium; a second refrigeration cycle, which includes an indoor heat exchanger, a refrigerant pump and a second pipe connecting them to circulate a second working medium; and a relay heat exchanger, which is located between the above-mentioned first refrigeration cycle and the above-mentioned second refrigeration cycle to perform heat exchange between them.

[0035] The first refrigeration cycle is configured as an outdoor unit installed outdoors. In the second refrigeration cycle, at least the indoor heat exchanger and the second pipe are configured as an indoor unit installed indoors. Furthermore, at least the relay heat exchanger and the refrigerant pump are configured as a relay unit independent of the outdoor unit and the indoor unit. At least a flammable refrigerant is used as a refrigerant component in the first working medium, and at least a fluoroolefin is used as a refrigerant component in the second working medium.

[0036] According to the refrigeration device of the above structure, an independent relay unit is inserted between an outdoor unit including a first refrigeration cycle and an indoor unit as a part of a second refrigeration cycle. The second refrigeration cycle includes a refrigerant pump but does not include a compressor. Since the refrigerant pump does not use refrigeration oil, it is possible to avoid refrigeration oil and the like from remaining in the second piping of the indoor unit as a part of the second refrigeration cycle. As a result, the refrigerant piping already installed in the indoor unit can be used roughly as it is.

[0037] Furthermore, in the first refrigeration cycle including the compressor, a first working medium having a flammable refrigerant as a main component is used, but the first refrigeration cycle is constituted as an outdoor unit. On the other hand, in the second refrigeration cycle, a second working medium having a fluoroolefin as a main component is used as a refrigerant component, but the second refrigeration cycle is constituted as an indoor unit and a relay unit. Thus, the first refrigeration cycle using the flammable refrigerant is clearly separated from the indoor unit via the relay unit. Therefore, the influence of the use of the flammable refrigerant can be further reduced by inserting the relay unit.

[0038] Furthermore, the first working medium circulating in the first refrigeration cycle including the compressor does not need to use fluoroolefins. Fluoroolefins are prone to undergo a disproportionation reaction under the conditions of high temperature and high pressure in the compressor, but if fluoroolefins are not used as the refrigerant component of the first working medium, there is no need to implement countermeasures against the disproportionation reaction in the first refrigeration cycle.

[0039] On the other hand, the second working medium containing fluoroolefin as the main component circulates in the second refrigeration cycle that does not include a compressor. In the refrigerant pump, the second working medium does not become high temperature and high pressure when it is sent out, so it can be considered that the disproportionation reaction of fluoroolefin does not substantially occur. Therefore, it is not necessary to implement a countermeasure against the disproportionation reaction in the second refrigeration cycle.

[0040] As a result, even when a flammable refrigerant or a fluoroolefin is used as a refrigerant component, a favorable operation of the refrigeration cycle can be achieved, and existing refrigerant piping can be utilized on the indoor side.

[0041] Hereinafter, a typical embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in all the drawings below, the same or corresponding elements are denoted by the same reference numerals, and their repeated descriptions are omitted.

[0042] (Implementation Method 1)

[0043] [Configuration example of refrigeration device]

[0044] Figure 1 The refrigeration device R1 shown is a representative configuration example of the first embodiment, and the refrigeration device R1 is controlled as an air conditioner. Figure 1 As shown, the refrigeration device R1 according to Embodiment 1 includes an outdoor unit 10 , an indoor unit 20 , and a relay unit 30 .

[0045] like Figure 1 As shown by the dotted line, the outdoor unit 10 includes a first pipe 11, an outdoor heat exchanger 12, an outdoor blower 13, a compressor 14, an expansion valve 15, a four-way valve 16, etc. In addition, the indoor unit 20 is similar to the outdoor unit 10. Figure 1 As shown by the dotted line, the relay unit 30 includes a second pipe 21, an indoor heat exchanger 22, an indoor blower 23, a refrigerant quantity regulating valve 24, etc. In addition, the relay unit 30 includes a first relay pipe 31a, a second relay pipe 31b, a relay heat exchanger 32, a pipe connection portion 33, a refrigerant pump 34, etc.

[0046] The first pipe 11 of the outdoor unit 10 is connected to the first relay pipe 31a of the relay unit 30 via the pipe connection portion 33. In the outdoor unit 10 and the relay unit 30, the first pipe 11 and the first relay pipe 31a are connected in series in a manner that circulates sequentially in the order of the compressor 14 via the four-way valve 16, the pipe connection portion 33, the relay heat exchanger 32, the pipe connection portion 33, the expansion valve 15, and the outdoor heat exchanger 12, thereby forming a first refrigeration cycle.

[0047] The first working medium circulates in the first refrigeration cycle. The first working medium contains at least a flammable refrigerant as a refrigerant component. In addition, since the first refrigeration cycle includes a compressor 14, the first working medium also includes a refrigeration oil for the compressor 14. The specific flammable refrigerant contained in the first working medium is not particularly limited. In the present embodiment 1, for example, saturated hydrocarbons such as propane, or slightly flammable refrigerants such as difluoromethane (R32) can be cited, but are not particularly limited. Preferably, saturated hydrocarbons with a small GWP can be used.

[0048] The first working medium may contain other non-flammable refrigerants in addition to the flammable refrigerant, and multiple refrigerants may be used as the flammable refrigerant. That is, the refrigerant component constituting the first working medium may be a single refrigerant of only one flammable refrigerant, a mixed refrigerant containing multiple flammable refrigerants, or a mixed refrigerant consisting of more than one flammable refrigerant and more than one non-flammable refrigerant. In addition, the first working medium may also contain other components such as additives known in the field of working media for refrigeration cycles. The specific refrigerant components will be described later.

[0049] In the first refrigeration cycle, first, the compressor 14 compresses the first working medium. The outdoor heat exchanger 12 performs heat exchange between the first working medium and outdoor air (external air). The outdoor blower 13 blows outdoor air to the outdoor heat exchanger 12. The expansion valve 15 is an expansion mechanism that expands the first working medium.

[0050] The discharge side and the suction side of the compressor 14 are connected to the four-way valve 16 respectively. The four-way valve 16 changes the flow direction of the first working medium by switching. When the discharge side of the compressor 14 is switched to the direction of the outdoor heat exchanger 12, it becomes a cooling operation, and when the discharge side of the compressor 14 is switched to the direction of the relay heat exchanger 32, it becomes a heating operation. The cooling operation and the heating operation will be described later. In addition, Figure 1 In FIG. 1 , the flow direction of the first working medium during cooling operation is indicated by a black solid arrow F1 , and the flow direction of the first working medium during heating operation is indicated by a white hollow arrow F2 .

[0051] As described above, the relay unit 30 is connected to both the outdoor unit 10 and the indoor unit 20. Specifically, the second pipe 21 of the indoor unit 20 and the second relay pipe 31b of the relay unit 30 are connected via the pipe connection portion 33.

[0052] In the indoor unit 20 and the relay unit 30, the second refrigeration cycle is formed by connecting the second pipe 21 (indoor unit 20) and the second relay pipe 31b in series in a manner that the refrigerant pump 34 (relay unit 30), the piping connection part 33, the refrigerant quantity regulating valve 24, the indoor heat exchanger 22 (indoor unit 20), the piping connection part 33, and the relay heat exchanger 32 (relay unit 30) circulate in this order.

[0053] The second working medium circulates in the second refrigeration cycle. The second working medium contains at least a fluoroolefin as a refrigerant component. The fluoroolefin contained in the second working medium is, for example, 1,2,2-trifluoroethylene (HFO1123) in the present embodiment 1, but is not particularly limited. The second working medium may be a single refrigerant of only HFO1123, or a mixed refrigerant containing other refrigerant components in addition to HFO1123. In addition, the second working medium may also contain other components such as additives that are well known in the field of working media for refrigeration cycles. The specific refrigerant components are described later.

[0054] The refrigerant pump 34 pressurizes the second working medium in the second relay pipe 31b and the second pipe 21. The indoor heat exchanger 22 performs heat exchange between the second working medium and the indoor air. The indoor air supply device 23 supplies the indoor air to the indoor heat exchanger 22. The second refrigeration cycle does not include a structure such as the four-way valve 16 in the first refrigeration cycle. Therefore, in the second refrigeration cycle, the second working medium circulates only in one direction. In addition, Figure 1 In FIG. 1 , the flow direction of the second working medium is illustrated by a black solid arrow F3.

[0055] The relay heat exchanger 32 is a structure surrounded by the first refrigeration cycle and the second refrigeration cycle, respectively. The relay heat exchanger 32 mainly performs heat exchange between the first working medium circulating in the first refrigeration cycle included in the outdoor unit 10 and the second working medium circulating in the second refrigeration cycle across the relay unit 30 and the indoor unit 20. Therefore, the first refrigeration cycle and the second refrigeration cycle can be thermally connected via the relay heat exchanger 32.

[0056] In this way, the refrigeration device R1 of the present invention is configured as a binary cycle via the relay heat exchanger 32 included in the relay unit 30, and the relay heat exchanger 32 performs heat exchange between the first working medium and the second working medium. As a result, the first refrigeration cycle and the second refrigeration cycle, which are respectively independent refrigeration cycles, can be controlled cooperatively as one refrigeration device R1.

[0057] In the present invention, the specific structure of the outdoor heat exchanger 12, outdoor blower 13, compressor 14, expansion valve 15, four-way valve 16, indoor heat exchanger 22, indoor blower 23, piping connection part 33, refrigerant pump 34, and relay heat exchanger 32 included in the refrigeration device R1 is not particularly limited, and structures known in the field of refrigeration devices can be appropriately used.

[0058] The outdoor heat exchanger 12 can be considered as a "condenser" of a general refrigeration device. Similarly, the indoor heat exchanger 22 can be considered as an "evaporator" of a general refrigeration device. Therefore, as the outdoor heat exchanger 12, a well-known heat exchanger can be used as a condenser, and as the indoor heat exchanger 22, a well-known heat exchanger can be used as an evaporator. As such a heat exchanger, for example, a plate heat exchanger, a double tube heat exchanger, a shell and tube heat exchanger, etc. can be cited, but there is no particular limitation.

[0059] The relay heat exchanger 32 can also appropriately use a known heat exchanger similar to the outdoor heat exchanger 12 or the indoor heat exchanger 22. In particular, the relay heat exchanger 32 does not perform heat exchange between the working medium and the air (outdoor air or indoor air) like the outdoor heat exchanger 12 or the indoor heat exchanger 22, but performs heat exchange between the first working medium and the second working medium. Therefore, as the relay heat exchanger 32, the type of heat exchanger can be selected according to the types of the first working medium and the second working medium.

[0060] In the present invention, the first working medium has a flammable refrigerant as a refrigerant component as a main component, and the second working medium has a fluoroolefin as a refrigerant component as a main component. In this way, if the first working medium and the second working medium both have a known refrigerant component as a main component, a plate heat exchanger can be used.

[0061] As the compressor 14, a known sealed refrigerant compressor can be preferably used. The sealed refrigerant compressor may be any type such as a reciprocating type, a rotary type, a scroll type, a screw type, etc. In addition, the electric component of the refrigerant compressor can be any type as long as it has the same structure as a known electric motor, and may be an outer rotor type electric motor or an inner rotor type electric motor.

[0062] The refrigerant pump 34 may be any known structure for delivering the refrigerant (working medium for refrigeration cycle). Examples of common pumps include reciprocating positive displacement pumps such as piston pumps, plunger pumps, and diaphragm pumps; rotary positive displacement pumps such as gear pumps and screw pumps; centrifugal pumps such as multistage pumps, vertical pumps, self-priming pumps, closed pumps, and magnetic pumps; and cascade pumps.

[0063] In the present invention, as long as the second working medium can be sent out well and circulated well in the second refrigeration cycle, the specific structure of the refrigerant pump 34 is not particularly limited. However, since the second working medium contains fluoroolefin as a refrigerant component, from the viewpoint of greatly suppressing the risk of disproportionation reaction of fluoroolefin, a structure in which the motor included in the refrigerant pump 34 is arranged in a manner not to contact the second working medium can be cited.

[0064] The disproportionation reaction of fluoroolefins is likely to occur under high temperature and high pressure conditions as in the compressor 14, and is particularly likely to occur if discharge occurs in the compressor 14. The refrigerant pump 34 can deliver the second working medium without being under high temperature and high pressure conditions, so there is almost no possibility of the disproportionation reaction of fluoroolefins.

[0065] However, when the electric motor included in the refrigerant pump 34 discharges, the possibility of disproportionation of fluoroolefin cannot be completely eliminated due to the overlap of some unpredictable conditions. Therefore, as long as the electric motor included in the refrigerant pump is set in a manner that does not contact the second working medium, the electric motor that may cause discharge can be isolated from the second working medium. Therefore, if the structure of fluoroolefin is provided, the risk of disproportionation reaction can be greatly reduced.

[0066] The expansion valve 15 may be a temperature automatic expansion valve, an electronic expansion valve, or other expansion mechanisms known in the field of refrigeration cycles. The four-way valve 16, the outdoor air blower 13, the indoor air blower 23, etc. may also appropriately use various structures known in the field of refrigeration devices.

[0067] The specific structure of the pipe connection part 33 is not particularly limited, and a structure known in the field of refrigeration devices or refrigeration cycles can be preferably used. In particular, in the present invention, from the perspective of using the existing refrigerant pipes roughly as they are, the pipe connection part 33 can adopt a structure in which a joint (joint for refrigerant pipes) is inserted, rather than a structure in which the connection part is integrated by welding or the like. As a result, the operation of replacing high GWP refrigerant components (such as HCFC or HFC) with fluoroolefins used in the prior art can be made more efficient.

[0068] Next, the representative operation of the refrigeration device R1 is described. First, the cooling operation is described. In the first refrigeration cycle with the outdoor unit 10 as the main body, the high-temperature and high-pressure first working medium compressed by the compressor 14 is sent to the outdoor heat exchanger 12 via the four-way valve 16 (arrow F1 direction). In the outdoor heat exchanger 12, the first working medium becomes a high-pressure and medium-temperature liquid through heat exchange with the outdoor air (external air) sent by the outdoor blower 13 and is sent to the expansion valve 15.

[0069] The first working medium is expanded by the expansion valve 15 to become a gas-liquid mixed state of low pressure and low temperature, and is sent to the relay heat exchanger 32 through the first pipe 11 of the outdoor unit 10, the pipe connection part 33 and the first relay pipe 31a of the relay unit 30. In the relay heat exchanger 32, heat exchange is performed between the first working medium and the second working medium of the second refrigeration cycle, and the first working medium becomes a low pressure and medium temperature gas and is sucked into the suction side of the compressor 14 through the four-way valve 16.

[0070] In the second refrigeration cycle across the relay unit 30 and the indoor unit 20, the second working medium is sent to the relay heat exchanger 32 (in the direction of the black solid arrow F3) by the refrigerant pump 34. In the relay heat exchanger 32, as described above, heat exchange is performed between the first working medium and the second working medium. As a result, the second working medium is cooled by the low-temperature and low-pressure first working medium and sent to the indoor heat exchanger 22 via the second relay pipe 31b of the relay unit 30, the pipe connection portion 33, and the second pipe 21 of the indoor unit 20.

[0071] As viewed from the indoor heat exchanger 22, a refrigerant quantity regulating valve 24 is provided on the upstream side of the second working medium, so the flow rate of the second working medium flowing into the indoor heat exchanger 22 is regulated by the refrigerant quantity regulating valve 24. In the indoor heat exchanger 22 into which the second working medium flows, heat exchange is performed with the indoor air blown by the indoor blower 23. As a result, the indoor air is cooled by the second working medium, and cooling is performed indoors. The second working medium sent out from the indoor heat exchanger 22 is returned to the refrigerant pump 34 via the second piping 21, the piping connection portion 33, and the second relay piping 31b.

[0072] Next, the heating operation is described. In the first refrigeration cycle, the high-temperature and high-pressure first working medium compressed by the compressor 14 is sent to the relay heat exchanger 32 (arrow F2 direction) via the four-way valve 16, the first pipe 11 of the outdoor unit 10, the pipe connection part 33, and the first relay pipe 31a of the relay unit 30. In the relay heat exchanger 32, heat is exchanged between the first working medium and the second working medium of the second refrigeration cycle, and the first working medium becomes a high-pressure, medium-temperature liquid and is sent to the expansion valve 15.

[0073] The first working medium is expanded in the expansion valve 15 to become a low-temperature and low-pressure gas-liquid mixed state and is sent to the outdoor heat exchanger 12. In the outdoor heat exchanger 12, the first working medium is heat-exchanged with the outdoor air blown by the outdoor blower 13, and becomes a low-pressure and medium-temperature gas and is sucked into the suction side of the compressor 14.

[0074] In the second refrigeration cycle, the second working medium is sent to the relay heat exchanger 32 by the refrigerant pump 34. In the relay heat exchanger 32, as described above, heat exchange is performed between the first working medium and the second working medium. As a result, the second working medium is heated by the high-temperature and high-pressure first working medium and is sent to the indoor heat exchanger 22 via the second relay pipe 31b of the relay unit 30, the pipe connection portion 33, and the second pipe 21 of the indoor unit 20.

[0075] In the indoor heat exchanger 22, the indoor air is heated by the second working medium by exchanging heat with the indoor air blown by the indoor blower 23, thereby heating the room. The second working medium sent out from the indoor heat exchanger 22 has its flow rate regulated by the refrigerant quantity regulating valve 24, and is returned to the refrigerant pump 34 via the second piping 21, the piping connection 33, and the second relay piping 31b.

[0076] As described above, in the refrigeration device R1 of the present embodiment, the first refrigeration cycle is constituted as the outdoor unit 10, at least the indoor heat exchanger 22 and the second pipe 21 in the second refrigeration cycle are constituted as the indoor unit 20, and at least the relay heat exchanger 32 and the refrigerant pump 34 are constituted as the relay unit 30. Furthermore, at least a flammable refrigerant is used as the first working medium as a refrigerant component, and at least a fluoroolefin is used as the second working medium as a refrigerant component.

[0077] The second refrigeration cycle includes the refrigerant pump 34 but does not include the compressor 14, and the refrigerant pump 34 does not use refrigeration oil. Therefore, it is substantially possible to avoid refrigeration oil or its compound remaining in the second pipe 21 of the indoor unit 20 as part of the second refrigeration cycle.

[0078] Generally, in the refrigerant piping of the refrigeration cycle including the compressor 14 using refrigeration oil, refrigeration oil remains inside, so the existing refrigerant piping cannot be used as it is, and it is necessary to clean the inside or replace all the refrigerant piping, etc. In this embodiment, the second refrigeration cycle on the indoor side does not include the compressor 14, so refrigeration oil, etc. are not mixed in the second piping 21 on the indoor side.

[0079] Therefore, it is possible to avoid refrigeration oil and the like from remaining in the second piping 21, so that, for example, even when the refrigerant component is switched from a high-GWP refrigerant component to a low-GWP refrigerant component, the existing refrigerant piping can be used in the indoor unit 20 substantially as is.

[0080] In addition, in the first refrigeration cycle including the compressor 14, a first working medium having a flammable refrigerant as a main component is used, but the first refrigeration cycle is constituted as an outdoor unit 10. On the other hand, in the second refrigeration cycle, it is not necessary to use a flammable refrigerant as a refrigerant component. Thus, the first refrigeration cycle using a flammable refrigerant is clearly separated from the indoor unit 20 via the relay unit 30. Therefore, by inserting the relay unit 30, the influence caused by the use of the flammable refrigerant can be further reduced.

[0081] Furthermore, by making the flammable refrigerant as the main component of the refrigerant of the first working medium a saturated hydrocarbon, a refrigerant component with a lower GWP can be used. In addition, by arranging the relay unit 30 outdoors, the first refrigeration cycle in which the first working medium circulates is entirely located outdoors. Therefore, saturated hydrocarbons are not used in the refrigerant component of the second refrigeration cycle mainly indoors. Therefore, by inserting the relay unit 30, the impact caused by the use of saturated hydrocarbons as a flammable refrigerant can be further reduced.

[0082] [Configuration Example of First Working Medium and Second Working Medium]

[0083] Next, the first working medium and the second working medium used in the refrigeration device R1 of the present invention will be described in detail.

[0084] First, the first working medium used in the first refrigeration cycle may contain a flammable refrigerant as a refrigerant component. Typical flammable refrigerants include saturated hydrocarbons.

[0085] Specific examples of the saturated hydrocarbon include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), and methylcyclobutane.

[0086] In addition, as other flammable refrigerants, there can be mentioned refrigerants (for convenience, referred to as "flammable HFCs") classified as A2 (flammable) or A2L (slightly flammable) in the safety level of ASHRAE34 among hydrofluorocarbons (HFCs). Examples of such flammable HFCs include difluoromethane (R32, A2L) and 1,1-difluoroethane (R152a, A2).

[0087] These flammable refrigerants may be used alone or in combination of two or more thereof. Among them, a representative example of saturated hydrocarbons is n-propane, and a representative example of flammable HFCs is R32.

[0088] Next, the second working medium used in the second refrigeration cycle may contain at least fluoroolefin (fluoroalkene) as a refrigerant component. The specific types of fluoroolefins are not particularly limited, and examples thereof include fluoroethylenes such as 1,1,2-trifluoroethylene (HFO1123), trans-1,2-difluoroethylene (HFO1132(E)), cis-1,2-difluoroethylene (HFO1132(Z)), 1,1-difluoroethylene (HFO1132a), tetrafluoroethylene (FO1114, TFE), and monofluoroethylene (HFO1141); and fluoropropylenes such as 1,2,3,3,3-pentafluoropropylene (HFO-1225ye), 2,3,3,3-tetrafluoropropylene (HFO-1234yf), 1,3,3,3-tetrafluoropropylene (HFO-1234ze), 1,2,3,3-tetrafluoropropylene (HFO-1234ye), and 3,3,3-trifluoropropylene (HFO-1243zf).

[0089] These fluoroolefins may be used alone or in combination of two or more thereof as the refrigerant component. Among these, vinyl fluoride may be preferably used as the refrigerant component, and among these vinyl fluorides, 1,1,2-trifluoroethylene (HFO1123) may be particularly preferably used.

[0090] The second working medium may contain other refrigerant components besides fluoroolefins. Such other refrigerant components are not particularly limited, and typical examples thereof include natural refrigerants such as hydrofluorocarbons (HFCs), carbon dioxide (carbonic acid gas), ammonia, hydrocarbons, and nitrogen.

[0091] Specific examples of HFCs include fluoromethanes such as difluoromethane (R32) and trifluoromethane (R23); fluoroethanes such as fluoroethane (R161), 1,1-difluoroethane (R152a), 1,1,1-trifluoroethane (R143a), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane (R134a), pentafluoroethane (R125), difluoroethane, and trifluoroethane; and fluoroethanes such as 1,1,1,3,3-pentafluoropropane (R245 Fluoropropanes such as 1,1,1,2,3,3-hexafluoropropane (R236ea), 1,1,1,3,3,3-hexafluoropropane (R236fa), and 1,1,1,2,3,3,3-heptafluoropropane (R227ea); Fluorobutanes such as 1,1,1,3,3-pentafluorobutane (R365mfc); Fluoropentanes such as 1,1,1,2,3,4,4,5,5,5-decafluoropentane (R4310mee), and heptafluorocyclopentane (Rc447ef).

[0092] These other refrigerants may be used alone or in combination of two or more thereof. Among them, R32 (difluoromethane) is preferably used as a representative refrigerant.

[0093] In the present invention, it is known that the second working medium contains fluoroolefins, and the fluoroolefins undergo a disproportionation reaction. However, as described above, the second refrigeration cycle in which the second working medium circulates does not include the compressor 14, and the refrigerant pump 34 included in the second refrigeration cycle uses a refrigerant pump that does not make the second working medium high-temperature and high-pressure like the compressor 14. In addition, the refrigerant pump 34 may also be a structure that prevents the electric motor that may discharge from contacting the second working medium. Therefore, in the present invention, it is considered that the disproportionation reaction can be substantially avoided in the fluoroolefins contained in the second working medium.

[0094] However, considering the possibility that the fluoroolefin may undergo a disproportionation reaction due to unknown or unexpected conditions, the second working medium may contain a disproportionation inhibitor for inhibiting the disproportionation reaction of the fluoroolefin.

[0095] Specific disproportionation inhibitors are not particularly limited, and examples thereof include saturated hydrocarbons having 2 to 5 carbon atoms, halogenated alkanes having any of 1 to 4 carbon atoms except when all halogen atoms are fluorine, or fluoroalkanes having 1 to 3 carbon atoms with a boiling point of 0° C. or less. For convenience of description, saturated hydrocarbons used as disproportionation inhibitors are referred to as “disproportionation-inhibited alkanes”, halogenated alkanes used as disproportionation inhibitors are referred to as “disproportionation-inhibited halogenated alkanes”, and fluoroalkanes used as disproportionation inhibitors are referred to as “disproportionation-inhibited fluoroalkanes”.

[0096] The disproportionation-inhibiting alkane used as the disproportionation inhibitor in the present invention may be any saturated hydrocarbon (alkane) having 2 to 5 carbon atoms as described above, and specifically, may include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), methylcyclobutane, etc. These saturated hydrocarbons may be used alone or in combination of two or more thereof.

[0097] These saturated hydrocarbons are all gases at room temperature (the boiling points of normal pentane and methylcyclobutane are about 36°C, the highest, and the boiling points of other hydrocarbons are lower than 36°C), and can be well mixed with the refrigerant component of the second working medium. Saturated hydrocarbons with a carbon number of 6 or more are liquids at room temperature, so they are difficult to mix with the refrigerant component of the second working medium, and are therefore not preferred.

[0098] In addition, methane, a saturated hydrocarbon having 1 carbon atom, has a particularly large global warming potential (GWP), and is therefore not preferred. Also, among saturated hydrocarbons having 2 to 5 carbon atoms, cyclopentane has a boiling point of 49° C. and is liquid at room temperature, but can be used as a disproportionation inhibitor in the present invention.

[0099] In the present invention, the disproportionation-inhibiting halogenated alkane used as the disproportionation inhibitor may be any halogenated alkane having any one of 1 to 4 carbon atoms and all halogen atoms being fluorine. More specifically, halogenated methyl ether having 1 carbon atom (halogenated methyl ether), halogenated ethyl ether having 2 carbon atoms (halogenated ethyl ether), halogenated propyl ether having 3 carbon atoms (halogenated propyl ether), halogenated butyl ether having 4 carbon atoms (halogenated butyl ether), etc. are listed. In addition, the substance in which all halogen atoms are substituted by fluorine corresponds to the disproportionation-inhibiting fluoroalkane described later.

[0100] As the disproportionation-inhibited halogenated alkane, any one of methyl halide, ethyl halide, propyl halide or butyl halide can be used, and two or more of these disproportionation-inhibited halogenated alkanes can also be appropriately selected and used together. The two or more selections mentioned here not only include the case of selecting two or more disproportionation-inhibited halogenated alkanes with different numbers of carbon atoms (for example, a combination of any methyl halide and any methyl halide), but also include the case of selecting two or more disproportionation-inhibited halogenated alkanes with the same number of carbon atoms and different types of halogenated alkanes substituted with halogen atoms (for example, a combination of a first ethyl halide and a second ethyl halide different therefrom). In addition, the butyl halide can be a straight-chain structure or a branched structure (i.e., a structure having the same carbon skeleton as isobutane or 2-methylpropane).

[0101] More specifically, the disproportionation-suppressed halogenated alkane includes a substance having the structure of the following formula (1).

[0102] C p H q X r ···(1)

[0103] Wherein, X in formula (1) is a halogen atom selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), p is an integer of 1 or 2, q is an integer greater than 0, and r is an integer greater than 1, the sum of q and r is 2p+2, and when r is greater than 2, X is the same or different type of halogen atom.

[0104] However, from the disproportionation-suppressed halogenated alkanes represented by the above formula (1), disproportionation-suppressed halogenated alkanes in which X consists only of F are excluded. This is because the disproportionation-suppressed halogenated alkanes in which X consists only of F correspond to fluoromethane having 1 carbon atom or fluoroethane having 2 carbon atoms in the disproportionation-suppressed fluoroalkanes described later.

[0105] In the disproportionation-suppressed halogenated alkane represented by formula (1), the halogen atom X may be at least any one of F, Cl, Br and I as described above, but is preferably at least I. When the number of carbon atoms is 2 (p=2) and the number of halogen atoms is 2 or more (r≥2), the halogen atom X is preferably at least F and I.

[0106] When the disproportionation-inhibited halogenated alkane represented by formula (1) contains Cl and / or Br, the ozone depletion potential (ODP) tends to be high, and thus, the availability and operability may be limited. In addition, regardless of the type of the halogen atom X, the disproportionation-inhibited halogenated alkane represented by formula (1) also includes compounds with relatively large ozone depletion potential (ODP) and / or global warming potential (GWP).

[0107] However, in the present invention, even if the amount of the disproportionation-inhibiting halogenated alkane added as the disproportionation inhibitor in the second working medium is relatively small, it can effectively inhibit the disproportionation reaction of the fluoroolefin or alleviate the rapid progress of the disproportionation reaction. In addition, even if the disproportionation-inhibiting halogenated alkane is used together with other disproportionation inhibitors such as disproportionation-inhibiting alkanes, the total amount of the disproportionation inhibitor added is sufficiently small compared to the total amount of the first working medium. Therefore, even if a substance with a relatively large ODP or GWP is used as the disproportionation-inhibiting halogenated alkane, it will not have a significant impact on the environment.

[0108] The disproportionation-inhibiting halogenated alkane represented by formula (1) is not particularly limited, and specifically, examples thereof include: iodomethane (CH3I), diiodomethane (CH2I2), dibromomethane (CH2Br2), bromomethane (CH3Br), dichloromethane (CH2Cl2), chloroiodomethane (CH2ClI), dibromochloromethane (CHBr2Cl), tetraiodomethane (CI4), carbon tetrabromide (CBr4), chlorotribromomethane (CBrCl3), dibromodichloromethane (CBr2Cl2), tribromofluoromethane (CB4), chlorotribromomethane (CBrCl3), dibromodichloromethane (CBr2Cl2), tribromofluoromethane (CB4), chlorotribromomethane (CBrCl3), dibromodichloromethane (CBr2Cl2), tribromofluoromethane (CBr2Cl2), iodomethane (CH3I), dibromodichloromethane (CH3I), dibromofluoromethane (CH3Br), dibromomethane (CH3I), dibromochloromethane (CH3I), dibromofluoro ...chloromethane (CH3 r3F), fluorodiiodomethane (CHFI2), difluorodiiodomethane (CF2I2), dibromodifluoromethane (CBr2F2), trifluoroiodomethane (CF3I), difluoroiodomethane (CHF2I) and other halogenated ethanes; 1,1,1-trifluoro-2-iodoethane (CF3CH2I), monoiodoethane (CH3CH2I), monobromoethane (CH3CH2Br), 1,1,1-triiodoethane (CH3CI3), 1-bromide-2-iodotetrafluoroethane (CF2BrCF2I) and other halogenated ethanes, etc.

[0109] These disproportionation-inhibiting halogenated alkanes may be used alone or in combination of two or more. Among these, if the availability, ODP value, operability, etc. are taken into consideration, at least one selected from the group consisting of diiodomethane (CH2I2), difluorodiiodomethane (CF2I2), trifluoroiodomethane (CF3I), difluoroiodomethane (CHF2I), 1-bromo-2-iodotetrafluoroethane (CF2BrCF2I), and 1,1,1-trifluoro-2-iodoethane (CF3CH2I) may be particularly preferably used.

[0110] As described above, the disproportionation-inhibiting fluoroalkane used as the disproportionation inhibitor in the present invention may be any fluoroalkane having 1 to 3 carbon atoms and a boiling point of 0° C. or less. Fluorinated alkanes having 1 to 3 carbon atoms may be alkanes having 1 to 3 carbon atoms in which at least one of the hydrogen atoms contained in the alkanes having 1 to 3 carbon atoms is substituted with fluorine.

[0111] Specific examples of such disproportionation-inhibited fluoroalkanes include fluoromethane (boiling point -78.2°C), difluoromethane (boiling point -51.6°C), trifluoromethane (boiling point -84.4°C), tetrafluoromethane (boiling point -127.8°C), and the like; fluoroethane (boiling point -37.1°C), 1,1-difluoroethane (boiling point -24.7°C), 1,1,1-trifluoroethane (boiling point -47.2°C), 1,1,1,2-tetrafluoroethane (boiling point - Fluoropropanes such as 1-fluoropropane (boiling point -2.5°C), 2-fluoropropane (boiling point -10.0°C), 2,2-difluoropropane (boiling point -1.0°C), 1,1,1-trifluoropropane (boiling point -12.0°C), 1,1,2,2-tetrafluoropropane (boiling point -0.8°C), 1,1,1,3,3,3-hexafluoropropane (boiling point -1.4°C), etc. These fluoroalkanes may be used alone or in combination of two or more as the disproportionation inhibitor.

[0112] Among these fluoroalkanes, fluoropropane is a particularly representative compound. In the present invention, the fluoropropane that can be used as the disproportionation-suppressed fluoroalkane is a fluoropropane in which one or more hydrogen atoms of propane, an alkane having 3 carbon atoms, are replaced by fluorine atoms, and the boiling point is 0° C. or less. Specifically, for example, 1-fluoropropane or 2-fluoropropane (a compound in which one of the hydrogen atoms of propane is replaced by fluorine) can be cited, but the specific fluoropropane is of course not limited to these.

[0113] In addition, the disproportionation-inhibited fluoroalkane in the present invention is used as the second working medium together with the fluoroolefin which is the main component of the refrigerant component in the second working medium. The second working medium is a working medium for a refrigeration cycle, and therefore basically needs to be a gas within a normal temperature range. Therefore, the boiling point of the disproportionation-inhibited fluoroalkane needs to be 0°C or less.

[0114] For example, 1,2-difluoroethane (boiling point 31°C), 1,1,2-trifluoroethane (boiling point 5°C), 1,3-difluoropropane (boiling point 40°C to 42°C), 1,1,3,3-pentafluoropropane (boiling point 15.3°C), 1,1,2,2,3-pentafluoropropane (boiling point 25°C to 26°C), etc. have boiling points exceeding 0°C, and therefore cannot be used as disproportionation-suppressed fluoroalkanes in the present invention.

[0115] As described above, in the present invention, the second working medium is a refrigerant containing at least fluoroalkene, and may contain other refrigerant components such as HFC as needed, and may also contain a disproportionation inhibitor. In such a second working medium, there is no particular limitation on the content (content ratio) of fluoroalkene, the content of other refrigerant components, or the content (content ratio) of the disproportionation inhibitor, and the known content (range) may be used as it is, or a plurality of known contents may be appropriately combined for use.

[0116] As such, in the refrigeration device R1 of the present invention, the first working medium is a working medium whose main component is a flammable refrigerant as a refrigerant component, and the second working medium is a working medium whose main component is a fluoroolefin. Thus, the first working medium whose main component is a flammable refrigerant circulates in a first refrigeration cycle including the compressor 14, and the second working medium whose main component is a fluoroolefin circulates in a second refrigeration cycle not including the compressor 14. Therefore, the generation of disproportionation reaction in fluoroolefin can be substantially suppressed, and the flammable refrigerant circulates mainly with the outdoor unit 10, and the relay unit 30 is between the indoor unit 20 and the outdoor unit 10, so the possibility of various influences caused by the use of flammable refrigerant affecting the indoor space can be effectively suppressed.

[0117] In addition, both the first working medium and the second working medium may contain additives or other components known in the field of refrigeration devices or refrigeration cycles (or the field of working media for refrigeration cycles). For example, as described above, the first working medium compressed by the compressor 14 in the first refrigeration cycle may also contain refrigeration oil contained in the compressor 14 as a component of the first working medium.

[0118] As described above, in the refrigeration device R1 of the first embodiment, the first refrigeration cycle is configured as the outdoor unit 10, at least the indoor heat exchanger 22 and the second pipe 21 in the second refrigeration cycle are configured as the indoor unit 20, and at least the relay heat exchanger 32 and the refrigerant pump 34 are configured as the relay unit 30. In addition, at least a flammable refrigerant is used as the first working medium as a refrigerant component, and at least a fluoroolefin is used as the second working medium as a refrigerant component.

[0119] In such a refrigeration device R1, it is not necessary to use fluoroolefin as the first working medium circulating in the first refrigeration cycle including the compressor 14. Fluoroolefins are prone to undergo a disproportionation reaction under the conditions of high temperature and high pressure in the compressor 14, but if fluoroolefins are not used as the refrigerant component of the first working medium, it is not necessary to implement a countermeasure against the disproportionation reaction in the first refrigeration cycle.

[0120] On the other hand, the second working medium containing fluoroolefin as a main component circulates in the second refrigeration cycle which does not include the compressor 14. In the refrigerant pump 34 included in the second refrigeration cycle, the second working medium does not become high temperature and high pressure when it is sent out, so it can be considered that the disproportionation reaction of the fluoroolefin does not substantially occur. Therefore, it is not necessary to implement a countermeasure against the disproportionation reaction in the second refrigeration cycle.

[0121] As a result, even when a flammable refrigerant or a fluoroolefin is used as a refrigerant component, a favorable operation of the refrigeration cycle can be achieved, and existing refrigerant piping can be utilized on the indoor side.

[0122] Furthermore, in the present invention, fluoroolefin is used as the main component of the refrigerant in the second refrigeration cycle on the indoor side. Fluoroolefin can achieve high thermal efficiency comparable to that of the current HFC refrigerant R32, and can further reduce GWP.

[0123] Usually, in a refrigeration device including an outdoor unit and an indoor unit, for example, it is assumed that a flammable refrigerant is used in the refrigeration cycle on the outdoor side, and carbon dioxide or water is used in the refrigeration cycle on the indoor side. This is because even if carbon dioxide or water leaks into the room, the impact is small. However, carbon dioxide as a refrigerant is high-pressure, and the heat transfer capacity per unit flow of water is low, and a large flow rate needs to flow, so it is difficult to use the existing refrigerant piping. Therefore, in the refrigeration cycle on the indoor side, HFC refrigerants such as R32 with a relatively high GWP need to be used.

[0124] In contrast, in the present invention, a fluoroolefin having a thermal efficiency comparable to that of an HFC refrigerant such as R32 is used as the refrigerant (second working medium) of the second refrigeration cycle on the indoor side. Although it is known that there is a problem of disproportionation reaction in fluoroolefin, in the second refrigeration cycle, a refrigerant pump 34 is used to deliver the second working medium, and the second working medium does not become high temperature and high pressure in the refrigerant pump 34, so the disproportionation reaction of the fluoroolefin can be substantially suppressed.

[0125] In addition, fluoroolefins also include compounds that are difficult to (or do not) undergo disproportionation reactions, but such compounds tend to have poor practicality as refrigerant components. In the present invention, for example, 1,1,2-trifluoroethylene (HFO1123) is used as a representative fluoroolefin, and HFO1123 has excellent refrigerant performance, but on the other hand, it is easy to undergo disproportionation reactions.

[0126] In the present invention, since the second working medium is circulated in the second refrigeration cycle by using the refrigerant pump 34, the disproportionation reaction is originally difficult to occur, and as mentioned above, the second working medium can also contain a component that inhibits the disproportionation reaction (disproportionation inhibitor). As a result, even for fluoroolefins such as HFO1123 that are prone to disproportionation reaction, the possibility of disproportionation reaction due to unknown conditions or unexpected reasons can be greatly reduced.

[0127] (Implementation Method 2)

[0128] Figure 2 The refrigeration device R2 shown is a representative configuration example of the second embodiment. Figure 2 As shown, the refrigeration device R2 of this embodiment 2 includes an outdoor unit 10, an indoor unit 20 and a relay unit 30, similarly to the refrigeration device R1 of the above-mentioned embodiment 1. In addition, in the refrigeration device R2, similarly to the refrigeration device R1 of the above-mentioned embodiment 1, the first refrigeration cycle is constituted as the outdoor unit 10, the second refrigeration cycle is constituted in a manner spanning the indoor unit 20 and the relay unit 30, and the first refrigeration cycle and the second refrigeration cycle are thermally connected via the relay heat exchanger 32.

[0129] Here, the refrigeration device R2 according to Embodiment 2 includes a plurality of indoor units 20. Figure 2 Two indoor units 20 are shown in the figure, but in the refrigeration device R2 of this embodiment 2, there may be three or more indoor units 20. Each indoor unit 20 basically has the same structure, including a second pipe 21, an indoor heat exchanger 22, an indoor air blower 23, a refrigerant quantity regulating valve 24, etc.

[0130] In the refrigeration device R2 of Embodiment 2, the relay heat exchanger 32 included in the relay unit 30 is connected to the second pipes 21 in the plurality of indoor units 20 via the branching portion 25. Figure 2 In the refrigeration device R2 shown, the second relay pipe 31b connected to the indoor unit 20 in the relay unit 30 is connected to a plurality of (two) indoor units 20 via a pipe connection portion 33. This is the same as the refrigeration device R1 of the first embodiment, but a branch portion 25 is provided between the pipe connection portion 33 and the second pipe 21.

[0131] exist Figure 2In the example shown, the branch portion 25 is interposed between the pipe connection portion 33 and the second pipe 21 of the indoor unit 20, but may be interposed between the second relay pipe 31b of the relay unit 30 and the pipe connection portion 33. Figure 2 In the embodiment, there are two indoor units 20, so the branching portion 25 branches from the pipe connection portion 33 to the second pipe 21 in two, but if there are three or more indoor units 20, it is sufficient to branch to the second pipe 21 in three or more. The specific structure of the branching portion 25 is not particularly limited, and a known structure such as a common branch pipe or a branch-type joint in the field of refrigerant piping can be preferably used.

[0132] As described above, in the refrigeration device R2 of the second embodiment, the first refrigeration cycle serving as the heat source side is composed of a single outdoor unit 10, and the relay unit 30 is also single, and the second refrigeration cycle serving as the cooling and heating side is branched into a plurality of indoor units 20 via the relay heat exchanger 32 included in the relay unit 30. Thus, cooling and heating can be performed in a plurality of indoor rooms by a single heat source circuit.

[0133] (Implementation 3)

[0134] Figure 3 The refrigeration device R3 shown is a representative configuration example of the third embodiment. Figure 3 As shown, the refrigeration device R3 of the present embodiment 3 includes a single outdoor unit 10 and a single relay unit 30 similarly to the refrigeration device R2 of the above-mentioned embodiment 2, and includes a plurality of indoor units 20 ( Figure 3 There are two in the middle).

[0135] In addition, in the refrigeration device R3, similarly to the refrigeration device R1 of the above-mentioned embodiment 1 or the refrigeration device R2 of the above-mentioned embodiment 2, the first refrigeration cycle is constructed as an outdoor unit 10, and the second refrigeration cycle is constructed in a manner spanning the indoor unit 20 and the relay unit 30, and the first refrigeration cycle and the second refrigeration cycle are thermally connected through the relay heat exchanger 32.

[0136] Here, in the refrigeration device R3 of the present embodiment 3, unlike the refrigeration device R2 of the above-mentioned embodiment 2, there is no branching portion 25 between the relay heat exchanger 32 and the second pipe 21, and the relay heat exchanger 32 is configured in a manner interposed between a single first refrigeration cycle and a plurality of second refrigeration cycles. Figure 3 In the refrigeration device R3 shown, since there are two indoor units 20, there are also two second refrigeration cycles, and in the relay heat exchanger 32, a flow portion for the second working medium connected to two second refrigeration cycles is arranged in parallel with a flow portion for the first working medium connected to a single first refrigeration cycle. The same is true when there are three or more second refrigeration cycles.

[0137] According to the refrigeration device R3 of such a structure, the first refrigeration cycle serving as the heat source side is composed of a single outdoor unit 10, the relay unit 30 is also single, and the second refrigeration cycle serving as the cooling and heating side is provided in plurality, each constituting a plurality of indoor units 20. Thus, similarly to the refrigeration device R2 of the second embodiment, cooling and heating can be performed in a plurality of indoor rooms by a single heat source circuit.

[0138] In addition, when the refrigeration device R includes a plurality of indoor units 20, the structure including the branch portion 25 as shown in the above-mentioned embodiment 2, or the structure including the relay heat exchanger 32 capable of performing heat exchange between a plurality of second refrigeration cycles and a single first refrigeration cycle as shown in the above-mentioned embodiment 3 can be appropriately selected according to the installation conditions (conditions of the building or room to be installed, etc.) of the refrigeration device R. For example, when there are three or more indoor units 20, the structure disclosed in embodiment 2 and the structure disclosed in embodiment 3 can also be combined.

[0139] In the refrigeration device R2 of the second embodiment and the refrigeration device R3 of the third embodiment, the plurality of indoor units 20 have the same structure, but the structures of the indoor units 20 may be different depending on the conditions of the room where the indoor units 20 are installed. Figure 2 or Figure 3 In the figure, as the indoor unit 20, only the basic structure of the second piping 21, the indoor heat exchanger 22, the indoor air supply device 23 and the refrigerant quantity regulating valve 24 is illustrated, but in the actual indoor unit 20, in addition to the basic structure, it can also be customized according to the installation conditions of each indoor unit 20.

[0140] (Implementation 4)

[0141] Figure 4 The refrigeration device R4 shown is a representative configuration example of the present embodiment 4. Figure 4 As shown, the refrigeration device R4 according to Embodiment 4 includes an integrated outdoor unit 40 and an indoor unit 20 .

[0142] The integrated outdoor unit 40 is formed by integrating the outdoor unit 10 and the relay unit 30 in the refrigeration device R1 of the first embodiment, and is installed outdoors. Figure 4 As shown by the dotted line, the integrated outdoor unit 40 includes a first pipe 11, an outdoor heat exchanger 12, an outdoor blower 13, a compressor 14, an expansion valve 15, a four-way valve 16, a second relay pipe 31b, a relay heat exchanger 32, a pipe connection portion 33, a refrigerant pump 34, etc.

[0143] In the integrated outdoor unit 40, the first refrigeration cycle is constituted by connecting in series the first pipe 11 in such a manner that the compressor 14, the relay heat exchanger 32, the expansion valve 15, and the outdoor heat exchanger 12 are circulated in this order via the four-way valve 16. That is, the integrated outdoor unit 40 has substantially the same structure as the outdoor unit 10 and the relay unit 30 in the refrigeration device R1 except for the first relay pipe 31a and the pipe connection portion 33 connecting the first relay pipe 31a and the first pipe 11, which are not included in the refrigeration device R1 of the first embodiment.

[0144] In the refrigeration device R4 of the present embodiment 4, the structures of the indoor unit 20 and the second refrigeration cycle are substantially the same as those of the refrigeration device R1 of the above-mentioned embodiment 1. However, the difference is that the integrated outdoor unit 40 and the indoor unit 20 are connected by the connecting pipe 31c via the pipe connection portion 33. The structure of the connecting pipe 31c is the same as the first pipe 11, the second pipe 21, the second relay pipe 31b, etc.

[0145] That is, in the refrigeration device R4 of the present embodiment 4, the indoor unit 20 includes a second pipe 21, an indoor heat exchanger 22, an indoor blower 23, a refrigerant quantity regulating valve 24, etc., and the second refrigeration cycle is formed by connecting the second pipe 21 (indoor unit 20), the connecting pipe 31c and the second relay pipe 31b in series in a manner that circulates in the order of the refrigerant pump 34 (integrated outdoor unit 40), the pipe connection part 33, the indoor heat exchanger 22 (indoor unit 20), the pipe connection part 33, and the relay heat exchanger 32 (integrated outdoor unit 40).

[0146] According to such a refrigeration device R4, the first refrigeration cycle using a flammable refrigerant can be installed outdoors as a single integrated outdoor unit 40. As a result, the first working medium can be sealed in the integrated outdoor unit 40 (first refrigeration cycle) in advance. As a result, the sealing operation of the first working medium (refrigerant) can be omitted at the place where the refrigeration device R4 is installed, and the risk of leakage of the flammable refrigerant can be further reduced.

[0147] In addition, in the refrigeration device R1 of the above-mentioned embodiment 1, since the outdoor unit 10 and the relay unit 30 are independent of each other, the advantage of being able to omit the refrigerant sealing operation as in the refrigeration device R4 cannot be obtained. However, in the refrigeration device R1, since the outdoor unit 10 and the relay unit 30 can be respectively arranged at appropriate positions, there is an advantage that the installation freedom of the refrigeration device R1 is large.

[0148] In addition, in the refrigeration device R4 of the present embodiment 4, the case where there is only one indoor unit 20 is illustrated, but it is also possible to have a plurality of indoor units 20 as in the above-mentioned embodiment 2 or 3. In this case, in the refrigeration device R4, a structure including a branch portion 25 as in the refrigeration device R2 of the above-mentioned embodiment 2 may be adopted, and a structure including a relay heat exchanger 32 capable of heat exchange between a plurality of second refrigeration cycles and a single first refrigeration cycle as in the refrigeration device R3 of the above-mentioned embodiment 3 may be adopted.

[0149] (Implementation 5)

[0150] Figure 5 The refrigeration device R5 shown is a representative configuration example of the fifth embodiment. Figure 5 As shown, the refrigeration device R5 of the present embodiment 5 includes an integrated outdoor unit 40 and a single indoor unit 20, similarly to the refrigeration device R4 of the above-mentioned embodiment 4. However, in the present embodiment 5, Figure 5 As shown, the integrated outdoor unit 40 of the refrigeration device R5 includes a refrigerant tank 42 in which a first working medium is sealed, and the refrigerant tank 42 is connected to the second refrigeration cycle.

[0151] exist Figure 5 In the example shown, the third pipe 41 is branched from the second relay pipe 31b of the integrated outdoor unit 40 (but the side where the refrigerant pump 34 is not provided) to connect to the refrigerant tank 42. An electromagnetic valve 43 is provided between the third pipe 41 and the refrigerant tank 42. The position of the second relay pipe 31b to which the third pipe 41 is connected becomes the position between the relay heat exchanger 32 (integrated outdoor unit 40) and the indoor heat exchanger 22 (indoor unit 20) in the second refrigeration cycle.

[0152] More specifically, in the refrigeration device R5, the refrigerant pipes are connected in the order of the refrigerant pump 34 (integrated outdoor unit 40), the piping connection part 33, the refrigerant quantity regulating valve 24, the indoor heat exchanger 22 (indoor unit 20), the piping connection part 33, and the relay heat exchanger 32 (integrated outdoor unit 40), thereby forming a second refrigeration cycle.

[0153] In the second refrigeration cycle, the refrigerant pump 34 and the refrigerant quantity regulating valve 24 are connected by a connecting pipe 31c via a pipe connection portion 33, the refrigerant quantity regulating valve 24 and the indoor heat exchanger 22 are connected by a second pipe 21, the indoor heat exchanger 22 and the relay heat exchanger 32 are connected by a connecting pipe 31c via a pipe connection portion 33, and the relay heat exchanger 32 and the refrigerant pump 34 are connected via a second relay pipe 31b. The third pipe 41 is connected to the second relay pipe 31b on the side of the integrated outdoor unit 40 that is not connected to the refrigerant pump 34.

[0154] In the case of such a refrigeration device R5, a refrigerant tank 42 is provided in the integrated outdoor unit 40, and the second working medium is pre-sealed in the refrigerant tank 42. Figure 5 The second relay pipe 31b) and the second refrigeration cycle (in Figure 5 By connecting and evacuating the second pipe 21 connected to the indoor unit 20 via the connecting pipe 31c, the refrigeration device R5 can be put into a usable state.

[0155] That is, refrigeration device R5 has basically the same structure as refrigeration device R4 of Embodiment 4, so the first working medium can be sealed in the integrated outdoor unit 40 (first refrigeration cycle) in advance. Thus, as described above, the sealing operation of the first working medium can be omitted at a location where refrigeration device R5 is installed.

[0156] Furthermore, the integrated outdoor unit 40 of the refrigeration device R5 is provided with a refrigerant tank 42 that can be connected to the second refrigeration cycle. Therefore, the integrated outdoor unit 40 is provided, connected to the second pipe 21 of the indoor unit 20 via the connecting pipe 31c, and after the second pipe 21 is evacuated, the second working medium in the refrigerant tank 42 is supplied to the second refrigeration cycle by opening the solenoid valve 43. Thus, in the place where the refrigeration device R5 is provided, the sealing operation of the second working medium can be simplified. As a result, the man-hours for constructing the refrigeration device R5 can be reduced.

[0157] In addition, in the refrigeration device R5 of this embodiment 5, the case where there is only one indoor unit 20 is also illustrated, but it is also possible to adopt a structure including multiple indoor units 20 in the same way as in the above-mentioned embodiment 2 or 3, and a structure including a branch portion 25 in the same way as in the above-mentioned embodiment 2, and it is also possible to adopt a structure including a relay heat exchanger 32 capable of performing heat exchange between multiple second refrigeration cycles and a single first refrigeration cycle in the same way as in the above-mentioned embodiment 3.

[0158] (Note)

[0159] Through the description of each embodiment above, the following technology is disclosed in this specification.

[0160] (Technology 1) The refrigeration device involved in the present invention includes: a first refrigeration cycle, which has an outdoor heat exchanger, a compressor, an expansion mechanism and a first piping connecting them to circulate a first working medium; a second refrigeration cycle, which includes an indoor heat exchanger, a refrigerant pump and a second piping connecting them to circulate a second working medium; and a relay heat exchanger, which is located between the above-mentioned first refrigeration cycle and the above-mentioned second refrigeration cycle and performs heat exchange between them, the above-mentioned first refrigeration cycle is constituted as an outdoor unit arranged outdoors, and in the above-mentioned second refrigeration cycle, at least the above-mentioned indoor heat exchanger and the above-mentioned second piping are constituted as indoor units arranged indoors, and at least the above-mentioned relay heat exchanger and the above-mentioned refrigerant pump are constituted as relay units independent of the above-mentioned outdoor unit and the above-mentioned indoor unit, at least a flammable refrigerant is used as a refrigerant component in the above-mentioned first working medium, and at least a fluoroolefin is used as a refrigerant component in the above-mentioned second working medium.

[0161] (Technique 2) In the refrigeration device according to Technique 1, the flammable refrigerant is a saturated hydrocarbon, and the relay unit is installed outdoors.

[0162] (Technique 3) The refrigeration device according to Technique 1 or 2 includes a plurality of the indoor units, and the relay heat exchanger included in the relay unit is connected to the second pipes in the plurality of indoor units via a branch portion.

[0163] (Technique 4) The refrigeration device according to any one of Techniques 1 to 3, comprising a plurality of the indoor units, wherein the relay heat exchanger is interposed between the single first refrigeration cycle and the plurality of second refrigeration cycles.

[0164] (Technique 5) The refrigeration device according to any one of Techniques 1 to 4, wherein the outdoor unit and the relay unit are installed outdoors in an integrated manner.

[0165] (Technique 6) In the refrigeration device according to Technique 5, the outdoor unit includes a refrigerant tank in which the first working medium is sealed, and the refrigerant tank is connected to the second refrigeration cycle.

[0166] (Technique 7) In the refrigeration device according to any one of Techniques 1 to 7, the electric motor included in the refrigerant pump is provided so as not to come into contact with the second working medium.

[0167] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining technical solutions disclosed in different embodiments and a plurality of modifications are also included in the technical scope of the present invention.

[0168] In addition, according to the above description, many improvements and other embodiments of the present invention are obvious to those skilled in the art. Therefore, the above description should only be interpreted as an example, and is provided to teach those skilled in the art to perform the best mode of the present invention. Without departing from the gist of the present invention, the details of its structure and / or function can be substantially changed.

[0169] Possibility of industrial application

[0170] The present invention can be widely applied to the field of refrigeration apparatuses, particularly to the field of refrigeration apparatuses using a flammable refrigerant or a working medium containing fluoroolefin in a refrigeration cycle including a compressor.

[0171] Description of Reference Numerals

[0172] 10: Outdoor unit

[0173] 11: First piping

[0174] 12: Outdoor heat exchanger

[0175] 13: Outdoor air blower

[0176] 14: Compressor

[0177] 15: Expansion valve (expansion mechanism)

[0178] 16: Four-way valve

[0179] 20: Indoor unit

[0180] 21: Second piping

[0181] 22: Indoor heat exchanger

[0182] 23: Indoor air supply unit

[0183] 24: Refrigerant quantity regulating valve

[0184] 25: Branch

[0185] 30: Relay unit

[0186] 31a: First relay pipe

[0187] 31b: Second relay pipe

[0188] 31c: Connecting pipes

[0189] 32: Relay heat exchanger

[0190] 33: Piping connection

[0191] 34: Refrigerant pump

[0192] 40: Integrated outdoor unit

[0193] 41: The third pipe

[0194] 42: Refrigerant tank

[0195] 43: Solenoid valve.

Claims

1. A refrigeration device, characterized in that: include: A first refrigeration cycle includes an outdoor heat exchanger, a compressor, an expansion mechanism, and a first pipe connecting them to circulate a first working medium; A second refrigeration cycle includes an indoor heat exchanger, a refrigerant pump, and a second pipe connecting them to circulate a second working medium; and a relay heat exchanger, which is interposed between the first refrigeration cycle and the second refrigeration cycle, and performs heat exchange therebetween, The first refrigeration cycle is configured as an outdoor unit installed outdoors. In the second refrigeration cycle, at least the indoor heat exchanger and the second pipe are configured as an indoor unit installed indoors. Furthermore, at least the relay heat exchanger and the refrigerant pump are configured as relay units independent of the outdoor unit and the indoor unit. At least a flammable refrigerant is used as a refrigerant component in the first working medium. At least fluoroolefin is used as the refrigerant component in the second working medium.

2. The refrigeration device according to claim 1, characterized in that: The flammable refrigerant is a saturated hydrocarbon, The relay unit is arranged outdoors.

3. The refrigeration device according to claim 1 or 2, characterized in that: comprising a plurality of said indoor units, The relay heat exchanger included in the relay unit is connected to the second pipes in the plurality of indoor units via a branch portion.

4. The refrigeration device according to claim 1 or 2, characterized in that: comprising a plurality of said indoor units, The relay heat exchanger is interposed between the single first refrigeration cycle and the plurality of second refrigeration cycles.

5. The refrigeration device according to claim 1 or 2, characterized in that: The outdoor unit is integrally installed outdoors with the relay unit.

6. The refrigeration device according to claim 5, characterized in that: The outdoor unit includes a refrigerant tank in which the first working medium is sealed, and the refrigerant tank is connected to the second refrigeration cycle.

7. The refrigeration device according to claim 1, characterized in that: The electric motor included in the refrigerant pump is provided so as not to come into contact with the second working medium.

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