JP7171511B2 - refrigeration cycle equipment - Google Patents

Description

The present invention relates to a refrigeration cycle device.

Conventionally, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and the like have been used as refrigerants (working media) used in refrigeration cycle devices. However, the use of chlorine-containing refrigerants such as CFCs and HCFCs is currently regulated because they have a large impact on the ozone layer in the stratosphere (influence on global warming).

Therefore, in recent years, hydrofluorocarbons (HFCs), which do not contain chlorine and have little effect on the ozone layer, have been used as refrigerants. Known HFCs include, for example, R32 (difluoromethane), R125 (1,1,1,2,2-pentafluoroethane), and R134a (1,1,1,2-tetrafluoroethane).

For example, in a refrigeration cycle device such as a heat pump water heater (especially one that supplies high-temperature water), the temperature of the discharge gas from the compressor rises to a high temperature, and the high pressure side of the refrigeration cycle increases (the condensation temperature rises from 65 ° C. growing). In order to suppress this, R134a, R407C (three-kind mixed refrigerant consisting of R32, R125 and R134a), etc. are 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 values are based on the IPCC 4th report). In order to suppress global warming, it is desirable to use a refrigerant with a smaller GWP.

Refrigerants having a GWP of less than 10 include trifluoroethylene (1,1,2-trifluoroethene, HFO-1123, R1123, etc., hereinafter referred to as “HFO1123”), 2,3,3,3 -tetrafluoropropene (also called 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”) and the like are known. These refrigerants have carbon-carbon double bonds that are easily decomposed by OH radicals in the atmosphere, and are therefore considered to have little effect on the ozone layer.

HFO1123 is disclosed, for example, in Patent Document 1 (International Publication No. 2012/157764). Further, for example, Patent Document 2 (International Publication No. 2015/005290) and Patent Document 3 (International Publication No. 2015/141676) disclose mixed refrigerants containing HFO1123 and R1234yf.

WO2012/157764 WO2015/005290 WO2015/141676

HFO1123 is a refrigerant that has little impact on global warming (GWP of about 0.3) and can provide sufficient performance. However, a refrigerant with a high HFO1123 content has a problem that a disproportionation reaction (self-decomposition reaction) is likely to occur. Therefore, it is not preferable to use a large amount of HFO1123.

On the other hand, when R1234yf and HFO1216 are used in, for example, a heat pump water heater, the GWP can be greatly reduced, and the discharge gas temperature is lower than before, so it is possible to heat water to a higher temperature. ing.

However, since R1234yf and HFO1216 have low refrigerant densities and low latent heat, they have the demerit that the performance of the refrigeration cycle device is greatly reduced. Even if 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 achieve the same performance as a device. However, there are practical problems such as an increase in the size of the water heater and an increase in cost.

In addition, compared to conventional refrigerants, R1234yf and HFO1216 further lower the operating pressure on the low pressure side in the refrigerating cycle, so negative pressure (below atmospheric pressure) is generated in the refrigerating circuit of the refrigerating cycle device, air may be sucked into the circuit if the sealing performance of the The air sucked inside reacts with refrigerant, oil, etc. to deteriorate the refrigeration circuit, which may impair the reliability of the refrigeration cycle device. In particular, in a refrigeration cycle apparatus with a relatively low operating pressure, such as a heat pump hot water supply apparatus, negative pressure is likely to occur because the pressure inside the circuit is originally low.

The present invention has been made in view of the above problems, and has a refrigeration cycle apparatus that is less affected by global warming, has sufficient performance, does not generate negative pressure in the refrigeration circuit, and has high reliability. intended to provide

A refrigeration cycle apparatus for a heat pump 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 enclosed 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.

A refrigerating cycle device for a heat pump water heater according to the present invention includes a refrigerating circuit including a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion valve. A refrigerant is enclosed 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, does not generate negative pressure in the refrigeration circuit, and is highly reliable.

4 is a graph showing saturation temperatures of refrigerants according to Embodiment 1. FIG. 9 is a graph showing saturation temperatures of refrigerants according to Embodiment 2. FIG. 4 is a graph showing the discharge temperature of the refrigerant according to Embodiment 1. FIG. FIG. 5 is a schematic cross-sectional view for explaining effects of a modification of Embodiment 1; 1 is a schematic configuration diagram showing a refrigeration cycle apparatus according to Embodiment 1; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
[Embodiment 1]
First, an overview of the refrigeration cycle apparatus of this embodiment will be briefly described. FIG. 5 is a schematic configuration diagram showing a refrigeration cycle apparatus according to Embodiment 1. FIG. The refrigeration cycle device includes a refrigeration circuit including a compressor 1 , an outdoor heat exchanger 3 , an expansion valve 4 and an indoor heat exchanger 5 .

During hot water supply, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 1 flows into the indoor heat exchanger 5 and is condensed there. The liquid refrigerant condensed in the indoor heat exchanger 5 flows through the expansion valve 4 into the outdoor heat exchanger 3, where it evaporates (vaporizes). 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 device.

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

Next, the refrigerant sealed in the refrigerating circuit in this embodiment will be described. The refrigerant contains 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 a refrigerant according to Embodiment 1 (a graph indicated by a solid line indicated as HFO1123/R1234yf). This graph shows the saturation temperature for a mixed refrigerant composed of HFO1123 and R1234yf, and the "HFO1123 ratio" on the horizontal axis is the mass ratio of HFO1123 to the total amount of HFO1123 and R1234yf. Note that FIG. 1 also shows a line (chain line) indicating the saturation temperature of R407C.

From FIG. 1, it can be seen that when the HFO1123 ratio is 15% by mass or more, the saturation temperature is −33° C. or less. The lower limit of the ambient temperature at which the refrigeration cycle device (heat pump water heater) can be used is about -20°C. Therefore, 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, by setting the HFO1123 ratio to 15% by mass or more in the refrigerant used in the refrigeration cycle apparatus of the present embodiment, it is possible to suppress the occurrence of negative pressure in the refrigeration circuit.

In addition, in a refrigeration cycle apparatus having a relatively low operating pressure, such as a heat pump hot water supply apparatus, negative pressure is likely to occur because the pressure inside the circuit is originally low. Therefore, according to the present embodiment, the generation of negative pressure can be particularly effectively suppressed in the refrigeration cycle device for the heat pump water heater.

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

3 is a graph showing the discharge temperature of the refrigerant according to Embodiment 1. FIG. As shown in FIG. 3, when the refrigeration cycle device is a heat pump water heater and the HFO1123 ratio is 50% by mass or less, the discharge gas temperature is lowered by 10° C. or more from the conventional (when R407C is used as the refrigerant). (see Figure 3). Therefore, the operating pressure on the high pressure side can be increased by that amount, and the hot water supply temperature can be increased.

In addition, the GWP of the refrigerant of this embodiment is significantly lower than the GWP of R407A (1774) and the GWP of R134a (1430). 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 less affected by global warming, has sufficient performance, does not generate negative pressure in the refrigeration circuit, and is highly reliable. I understand.

The refrigerant used in the present embodiment may be a two- component mixed refrigerant consisting of only the above two components, or may further contain other refrigerant components. Other refrigerant components include, for example, R290, R1270, R134a, R125, etc. or other HFCs.

The compounding ratio of other components and the like are set within a range that does not interfere with the main effects of the present embodiment. Specifically, it is preferable to set the mixing ratio of the other components such that the total ratio of HFO1123 and HFO1216 to the total mass of the refrigerant is 90% by mass or more.

Moreover, the refrigerant may further contain refrigerating machine oil. The refrigerating machine oil includes, for example, commonly used refrigerating machine oils (ester-based lubricating oil, ether-based lubricating oil, fluorine-based lubricating oil, mineral-based lubricating oil, hydrocarbon-based lubricating oil, etc.). In that case, it is preferable to select a refrigerating machine oil that is excellent in terms of compatibility with the refrigerant, stability, and the like.

Moreover, the refrigerant may further contain a stabilizer as necessary, for example, when a high degree of stability is required under severe use conditions. Stabilizers are ingredients that improve the stability of a refrigerant against heat and oxidation. Examples of stabilizers include known stabilizers conventionally used in refrigeration cycle devices, such as oxidation resistance improvers, heat resistance improvers, and metal deactivators.

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

(Modification of Embodiment 1)
This modification differs from Embodiment 1 in that the lower limit of the HFO1123 ratio (the ratio of HFO1123 to the total amount of HFO1123 and R1234yf) is 33% by mass. Since other points are the same as those of the first embodiment, redundant description is omitted.

From FIG. 1, it can be seen that when the HFO1123 ratio is 33% by mass or more, the saturation temperature of the mixed refrigerant of HFO1123 and R1234yf is lower than the saturation temperature of R407C. In this case, in an existing refrigeration cycle device using R407C as a refrigerant, even if the refrigerant is switched to the refrigerant according to the present embodiment, it is possible to suppress poor lubrication at startup and ensure the reliability of the device. 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 modified example. Note that FIG. 4 shows a scroll compressor, and is basically the same diagram as FIG. 1 of Japanese Unexamined Patent Application Publication No. 2013-181516.

When the refrigeration cycle device is stopped (especially for a long time), the lubricating oil (refrigerating machine oil) in the oil supply route moves downward. A path from the oil surface of the oil reservoir 23 in the compressor to the oil supply pump (oil pump) 22 is filled with a low-pressure working medium. After that, when the refrigeration cycle apparatus is started, the oil in the oil reservoir 23 inside the compressor must be sucked up by the oil supply pump 22 and circulated inside the compressor.

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

Existing refrigeration cycle devices (heat pump water heaters) are designed so that the above formula holds for conventional refrigerants (such as R407C). That is, it is designed so that the above equation holds when Ps is the lowest operating pressure of conventional refrigerants.

When the saturation temperature of the refrigerant to be used is lower than the saturation temperature of R407C as in this modification, the minimum operating pressure of the refrigerant is higher than that of R407C. Therefore, even when the refrigerant is switched to the refrigerant according to the present embodiment in the existing refrigeration cycle device, it is considered that the above formula holds.

Therefore, according to this modified example, even when the refrigerant is switched to the refrigerant according to the present embodiment in the existing refrigeration cycle device, the reliability of the device is ensured by avoiding poor lubrication at the start of the refrigeration cycle device. can.

[Embodiment 2]
This embodiment differs from Embodiment 1 in that HFO1216 is used instead of R1234yf contained in the refrigerant. Other points are basically the same as those of the first embodiment, and duplicate descriptions will be omitted.

In this embodiment, the refrigerant sealed in the refrigeration circuit contains HFO1123 and HFO1216. The refrigerant used in the present embodiment may be a two- component mixed refrigerant consisting of only the above two components, or may further contain other refrigerant components. When the refrigerant contains other components, the total ratio of HFO1123 and HFO1216 to the total weight of the 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 Embodiment 2 (a graph indicated by a solid line indicated by HFO1123/HFO1216). This graph shows the saturation temperature for a 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. Note that FIG. 2 also shows a line (chain line) indicating the saturation temperature of R407C.

From FIG. 2, it can be seen 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 Embodiment 1, by setting the HFO1123 ratio to 10% by mass or more in the refrigerant used in the refrigeration cycle apparatus of this embodiment, it is possible to suppress the occurrence of negative pressure in the refrigeration circuit. .

The refrigerant used in this embodiment has a HFO1123 ratio of 50% by mass or less, which is the same as in the first embodiment, and the same effects as in the first embodiment can be obtained.

In addition, the GWP of the refrigerant of this embodiment is significantly lower than the GWP of R407A (1774) and the GWP of R134a (1430). 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 less affected by global warming, has sufficient performance, does not generate negative pressure in the refrigeration circuit, and is highly reliable. I understand.

(Modification of Embodiment 2)
This modification differs from Embodiment 2 in that the lower limit of the HFO1123 ratio (the ratio of HFO1123 to the total amount of HFO1123 and HFO1216) is 24% by mass. Since other points are the same as those of the second embodiment, redundant description is omitted.

From FIG. 2, it can be seen that when the HFO1123 ratio is 24% by mass or more, the saturation temperature of the mixed refrigerant of HFO1123 and HFO1216 is lower than the saturation temperature of R407C. In this case, in an existing refrigeration cycle device using R407C as a refrigerant, even if the refrigerant is switched to the refrigerant according to the present embodiment, it is possible to suppress poor lubrication at startup and ensure the reliability of the device. can. The reason for this is as explained in the modified example of the first embodiment.

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

Claims (1)

A refrigeration cycle device,
Equipped with 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,
The refrigerant contains HFO1123 and R1234yf,
The total ratio of HFO1123 and R1234yf to the total mass of the refrigerant is more than 90% by mass,
The ratio of HFO1123 to the total amount of HFO1123 and R1234yf is 33% by mass or more and 50% by mass or less,
A heat pump hot water supply designed so that ρgh is smaller than the minimum operating pressure of R407C, where ρ is the density of the refrigerating machine oil and h is the vertical distance from the oil surface of the oil reservoir in the compressor to the oil supply pump. Refrigeration cycle equipment for air conditioners.

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