JP6608038B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus.

  Conventionally, chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), and the like have been used as the refrigerant (working medium) used in the refrigeration cycle apparatus. However, refrigerants containing chlorine such as CFC and HCFC are currently restricted in use because they have a great influence on the ozone layer in the stratosphere (influence on global warming).

  For this reason, in recent years, hydrofluorocarbon (HFC) which does not contain chlorine and has little influence on the ozone layer has been used as a refrigerant. As HFCs, for example, R32 (difluoromethane), R125 (1,1,1,2,2-pentafluoroethane), and R134a (1,1,1,2-tetrafluoroethane) are known.

  For example, for refrigeration cycle devices (particularly those that supply high-temperature water) such as heat pump water heaters, the discharge gas temperature of the compressor becomes high, and the high-pressure side of the operating pressure in the refrigeration cycle increases (condensation temperature from 65 ° C. growing). In order to suppress this, R134a, R407C (a three-type mixed refrigerant composed of R32, R125, and R134a) or the like is used as a refrigerant (working medium), and in recent years, R407C is mainly used.

  However, the global warming potential (GWP) is 1774 for R407C and 1430 for R134a (the GWP value is based on the IPCC fourth report). In order to suppress global warming, it is desirable to use a refrigerant having a smaller GWP.

  As a refrigerant having a GWP of less than 10, trifluoroethylene (also referred to as 1,1,2-trifluoroethene, HFO-1123, R1123, etc., hereinafter referred to as “HFO1123”), 2, 3, 3, 3 -Tetrafluoropropene (also referred to as 2,3,3,3-tetrafluoro-1-propene, HFO-1234yf, R1234yf, etc., hereinafter referred to as "R1234yf"), hexafluoropropene (1,1,2,3) , 3,3-hexafluoro-1-propene, HFO1216, and R1216, hereinafter referred to as “HFO1216”). In addition, since these refrigerant | coolants have the carbon-carbon double bond which is easy to be decomposed | disassembled by OH radical in air | atmosphere, it is thought that there is little influence on an ozone layer.

  HFO1123 is disclosed in, for example, Patent Document 1 (International Publication No. 2012/157774). Further, for example, Patent Document 2 (International Publication No. 2015/005290) and Patent Document 3 (International Publication No. 2015/141676) disclose a mixed refrigerant containing HFO1123 and R1234yf.

International Publication No. 2012/157774 International Publication No. 2015/005290 International Publication No. 2015/141676

  HFO1123 is a refrigerant that has little influence on global warming (GWP is about 0.3) and can obtain sufficient performance. However, a refrigerant with a high content of HFO 1123 has a problem that a disproportionation reaction (self-decomposition reaction) easily occurs. For this reason, it is not preferable to increase the amount of HFO 1123 used.

  On the other hand, R1234yf and HFO1216 have the merit that, for example, GWP can be significantly reduced by using it in a heat pump type hot water heater, and the discharge gas temperature becomes lower than that of the conventional one, so that water can be heated to a higher temperature. ing.

  However, R1234yf and HFO1216 have a demerit that the capacity of the refrigeration cycle apparatus is greatly reduced because the density and latent heat of the refrigerant are small. Even when such a refrigerant is used, if the stroke volume, frequency, pipe diameter, etc. of the compressor are significantly increased (if the displacement is increased), it is possible to exert the same capability as the device. However, there are practical problems such as an increase in the size and cost of the water heater.

  In addition, R1234yf and HFO1216 are further reduced on the low pressure side of the operating pressure in the refrigeration cycle as compared with the conventional refrigerant, and therefore a negative pressure (below atmospheric pressure) portion is generated in the refrigeration circuit of the refrigeration cycle apparatus. There is a possibility that air will be sucked into the circuit when the sealing performance of the circuit is lowered. The air sucked into the interior reacts with the refrigerant, oil, and the like, thereby degrading the refrigeration circuit, and thus the reliability of the refrigeration cycle apparatus may be impaired. In particular, in a refrigeration cycle apparatus having a relatively low operating pressure, such as a heat pump type hot water supply apparatus, a negative pressure is likely to be generated because the pressure in the original circuit is low.

  The present invention has been made in view of the above-mentioned problems, has a sufficient performance, has a sufficient performance, does not generate a negative pressure in the refrigeration circuit, and has a high reliability. The purpose is to provide.

  A refrigeration cycle apparatus for a heat pump hot water supply apparatus according to the present invention includes a refrigeration circuit including a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion valve. A refrigerant is sealed in the refrigeration circuit, and the refrigerant contains HFO1123 and R1234yf, and the ratio of HFO1123 to the total amount of HFO1123 and R1234yf is 15% by mass or more and 50% by mass or less.

  The refrigeration cycle apparatus for a heat pump type hot water heater according to the present invention includes a refrigeration circuit including a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion valve. A refrigerant is sealed in the refrigeration circuit, and the refrigerant contains HFO1123 and HFO1216, and the ratio of HFO1123 to the total amount of HFO1123 and HFO1216 is 10% by mass or more and 50% by mass or less.

  According to the present invention, it is possible to provide a highly reliable refrigeration cycle apparatus that is less affected by global warming, has sufficient performance, and does not generate negative pressure in the refrigeration circuit.

3 is a graph showing a saturation temperature of the refrigerant according to the first embodiment. 6 is a graph showing the saturation temperature of the refrigerant according to the second embodiment. 4 is a graph showing the discharge temperature of the refrigerant according to the first embodiment. FIG. 10 is a schematic cross-sectional view for explaining an effect of a modification of the first embodiment. 1 is a schematic configuration diagram illustrating a refrigeration cycle apparatus according to Embodiment 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
First, the outline | summary of the refrigerating-cycle apparatus of this embodiment is demonstrated easily. FIG. 5 is a schematic configuration diagram illustrating the refrigeration cycle apparatus according to the first embodiment. The refrigeration cycle apparatus includes a refrigeration circuit including a compressor 1, an outdoor heat exchanger 3, an expansion valve 4, and an indoor heat exchanger 5.

  At the time of hot water supply, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 1 flows into the indoor heat exchanger 5 and condenses there. The liquid refrigerant condensed in the indoor heat exchanger 5 flows into the outdoor heat exchanger 3 via the expansion valve 4 and evaporates (vaporizes) there. The refrigerant evaporated in the outdoor heat exchanger 3 returns to the compressor 1. Thus, during heating, the refrigerant circulates in the direction of the arrow shown in FIG. 5 in the refrigeration circuit of the refrigeration cycle apparatus.

  The refrigeration cycle apparatus of the present embodiment may further include other devices such as a gas-liquid branching device, a receiver, an accumulator, and a high / low pressure heat exchanger.

  Next, the refrigerant sealed in the refrigeration circuit in the present embodiment will be described. The refrigerant includes HFO1123 and R1234yf.

  The ratio of HFO1123 to the total amount of HFO1123 and R1234yf is 15% by mass or more and 50% by mass or less. The lower limit of the ratio is preferably 33% by mass or more. The upper limit of the ratio is preferably less than 40% by mass, more preferably less than 29% by mass, and even more preferably less than 21% by mass.

  FIG. 1 is a graph showing the saturation temperature of the refrigerant according to the first embodiment (a graph indicated by a solid line described as HFO1123 / R1234yf). This graph shows the saturation temperature for the mixed refrigerant composed of HFO1123 and R1234yf, and the “HFO1123 ratio” on the horizontal axis is the mass ratio of HFO1123 with respect to the total amount of HFO1123 and R1234yf. In addition, in FIG. 1, the line (dashed line) which shows the saturation temperature of R407C is shown collectively.

  1 that the saturation temperature is −33 ° C. or lower when the HFO1123 ratio is 15 mass% or higher. The lower limit of the outside air temperature at which the refrigeration cycle apparatus (heat pump type hot water heater) can be used is about −20 ° C. For this reason, if the saturation temperature of the refrigerant is about −33 ° C. or lower, the generation of negative pressure in the refrigeration circuit is suppressed. Therefore, in the refrigerant used in the refrigeration cycle apparatus of the present embodiment, the generation of negative pressure in the refrigeration circuit can be suppressed by setting the HFO 1123 ratio to 15% by mass or more.

  In a refrigeration cycle apparatus having a relatively low operating pressure, such as a heat pump type hot water supply apparatus, a negative pressure is likely to be generated because the pressure in the original circuit is low. For this reason, according to this embodiment, generation | occurrence | production of a negative pressure can be suppressed especially effectively in the refrigerating cycle apparatus for heat pump type hot water heaters.

  On the other hand, the refrigerant used in the present embodiment has an HFO 1123 ratio set to 50% by mass or less. This is because when the HFO1123 ratio exceeds 50 mass%, the possibility of a disproportionation reaction (self-decomposition reaction) increases.

  FIG. 3 is a graph showing the discharge temperature of the refrigerant according to the first embodiment. As shown in FIG. 3, when the refrigeration cycle apparatus is a heat pump type hot water heater and the HFO1123 ratio is 50% by mass or less, the discharge gas temperature is lower by 10 ° C. or more than the conventional case (when R407C is used as the refrigerant). (See FIG. 3). For this reason, the high pressure side of the operating pressure can be increased correspondingly, and the hot water supply temperature can be increased.

  Further, the GWP of the refrigerant of the present embodiment is greatly reduced compared to the GWP (1774) of R407A and the GWP (1430) of R134a. Therefore, the refrigeration cycle apparatus of this embodiment has little influence on global warming.

  From the above, the refrigeration cycle apparatus of the present embodiment is highly reliable with little influence of global warming, sufficient performance, and no negative pressure generated in the refrigeration circuit. I understand.

  The refrigerant used in the present embodiment may be a three-component mixed refrigerant composed of only the above three components, and may further include other refrigerant components. Examples of other refrigerant components include R290, R1270, R134a, R125, and other HFCs.

  The blending ratio of the other components is set within a range that does not hinder the main effects of the present embodiment. Specifically, the blending ratio of the other components is preferably set so that the total ratio of HFO 1123 and HFO 1216 to the mass of the entire refrigerant is 90% by mass or more.

  The refrigerant may further contain refrigeration oil. Examples of the refrigerating machine oil include commonly used refrigerating machine oils (such as ester-based lubricating oils, ether-based lubricating oils, fluorine-based lubricating oils, mineral-based lubricating oils, and hydrocarbon-based lubricating oils). In that case, it is preferable to select a refrigerating machine oil that is superior in terms of compatibility with the refrigerant and stability.

  Further, the refrigerant may further contain a stabilizer as necessary, for example, when a high degree of stability is required under severe use conditions. A stabilizer is a component that improves the stability of the refrigerant against heat and oxidation. As a stabilizer, the well-known stabilizer conventionally used for the refrigerating-cycle apparatus, for example, an oxidation resistance improver, a heat resistance improver, a metal deactivator, etc. are mentioned.

  The refrigerant may further contain a polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinone, hydroquinone methyl ether, benzotriazole, and the like.

(Modification of Embodiment 1)
The present modification is different from the first embodiment in that the lower limit of the HFO 1123 ratio (the ratio of HFO 1123 to the total amount of HFO 1123 and R1234yf) is 33% by mass. Since the other points are the same as those of the first embodiment, a duplicate description is omitted.

  FIG. 1 shows that when the HFO1123 ratio is 33% by mass or more, the saturation temperature of the refrigerant mixture of HFO1123 and R1234yf is lower than the saturation temperature (4 ° C.) of R407C. In this case, in the existing refrigeration cycle apparatus in which R407C is used as the refrigerant, even when the refrigerant is switched to the refrigerant according to the present embodiment, it is possible to suppress poor oil supply at the time of startup and ensure the reliability of the apparatus. it can. This point will be described below with reference to FIG.

  FIG. 4 is a schematic cross-sectional view for explaining the effect of this modification. FIG. 4 shows a scroll compressor, which is basically the same as FIG. 1 of JP 2013-181516 A.

  When the refrigeration cycle apparatus is stopped (particularly for a long time), the lubricating oil (refrigerator oil) in the oil supply path moves downward. The path from the oil level of the oil sump 23 in the compressor to the oil supply pump (oil pump) 22 is filled with a low-pressure working medium. Thereafter, when the refrigeration cycle apparatus is started, it is necessary to suck up the oil in the oil reservoir 23 in the compressor by the oil supply pump 22 and circulate it in the compressor.

If the density of the refrigerating machine oil is ρ and the vertical distance from the oil level of the oil reservoir 23 to the oil supply pump 22 is h, then the pressure in the space between the oil surface of the oil reservoir 23 and the oil supply pump 22 is Ps. ,
ρgh <Ps
If so, the refrigerating machine oil can be sucked up from the oil reservoir 23 to the oil supply pump 22.

  In the existing refrigeration cycle apparatus (heat pump type hot water heater), the conventional refrigerant (R407C and the like) is designed so that the above formula is established. That is, it is designed so that the above equation is established when Ps is the minimum operating pressure of the conventional refrigerant.

  And when the saturation temperature of the refrigerant | coolant to be used is lower than the saturation temperature of R407C like this modification, the minimum operating pressure of this refrigerant | coolant will become higher than R407C. For this reason, in the existing refrigeration cycle apparatus, even when the refrigerant is switched to the refrigerant according to the present embodiment, the above formula is considered to hold.

  Therefore, according to this modification, even in the case where the refrigerant is switched to the refrigerant according to the present embodiment in the existing refrigeration cycle apparatus, the refueling failure at the start of the refrigeration cycle apparatus is avoided, and the reliability of the apparatus is ensured. it can.

[Embodiment 2]
The present embodiment is different from the first embodiment in that HFO 1216 is used instead of R1234yf contained in the refrigerant. Since the other points are basically the same as those of the first embodiment, a duplicate description is omitted.

  In the present embodiment, the refrigerant sealed in the refrigeration circuit includes HFO1123 and HFO1216. The refrigerant used in the present embodiment may be a three-component mixed refrigerant composed of only the above three components, and may further include other refrigerant components. When the refrigerant includes other components, the total ratio of HFO 1123 and HFO 1216 to the mass of the entire refrigerant is preferably 90% by mass or more.

  The ratio of HFO1123 to the total amount of HFO1123 and HFO1216 is 10% by mass or more and 50% by mass or less. The lower limit of the ratio is preferably 24% by mass or more. The upper limit of the ratio is preferably less than 40% by mass, more preferably less than 30% by mass.

  FIG. 2 is a graph showing the saturation temperature of the refrigerant according to the second embodiment (a graph indicated by a solid line described as HFO1123 / HFO1216). This graph shows the saturation temperature for the mixed refrigerant composed of HFO1123 and HFO1216, and the “HFO1123 ratio” on the horizontal axis is the mass ratio of HFO1123 to the total amount of HFO1123 and HFO1216. In addition, in FIG. 2, the line (dashed line) which shows the saturation temperature of R407C is shown collectively.

  FIG. 2 shows that when the HFO1123 ratio is 10% by mass or more, the saturation temperature is −33 ° C. or less. Therefore, for the same reason as in the first embodiment, in the refrigerant used in the refrigeration cycle apparatus of the present embodiment, the generation of negative pressure in the refrigeration circuit can be suppressed by setting the HFO1123 ratio to 10% by mass or more. .

  In addition, in the refrigerant | coolant used for this embodiment, it is the same as that of Embodiment 1 about the point by which HFO1123 ratio is set to 50 mass% or less, and there exists an effect similar to Embodiment 1. FIG.

  Further, the GWP of the refrigerant of the present embodiment is greatly reduced compared to the GWP (1774) of R407A and the GWP (1430) of R134a. Therefore, the refrigeration cycle apparatus of this embodiment has little influence on global warming.

  From the above, the refrigeration cycle apparatus of the present embodiment is highly reliable with little influence of global warming, sufficient performance, and no negative pressure generated in the refrigeration circuit. I understand.

(Modification of Embodiment 2)
This modification is different from the second embodiment in that the lower limit of the HFO 1123 ratio (the ratio of HFO 1123 to the total amount of HFO 1123 and HFO 1216) is 24 mass%. Since the other points are the same as those of the second embodiment, the overlapping description is omitted.

  2 that the saturation temperature of the mixed refrigerant of HFO 1123 and HFO 1216 is lower than the saturation temperature (4 ° C.) of R407C when the HFO 1123 ratio is 24% by mass or more. In this case, in the existing refrigeration cycle apparatus in which R407C is used as the refrigerant, even when the refrigerant is switched to the refrigerant according to the present embodiment, it is possible to suppress poor oil supply at the time of startup and ensure the reliability of the apparatus. it can. The reason for this is as described in the modification of the first embodiment.

  1 compressor, 2 flow path switching valve, 3 outdoor heat exchanger, 4 expansion valve, 5 indoor heat exchanger.

Claims (2)

A refrigeration circuit including a compressor, an outdoor heat exchanger, an indoor heat exchanger and an expansion valve;
A refrigerant is enclosed in the refrigeration circuit,
The refrigerant contains HFO1123 and HFO1216,
A refrigeration cycle apparatus for a heat pump water heater, wherein the ratio of HFO 1123 to the total amount of HFO 1123 and HFO 1216 is 10% by mass or more and 50% by mass or less. The refrigeration cycle apparatus according to claim 1 , wherein a ratio of HFO 1123 to a total amount of HFO 1123 and HFO 1216 is 24 mass% or more and 50 mass% or less.

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