JP6821075B1 - Refrigeration cycle equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle apparatus having high environmental compatibility and reliability, which uses a nonflammable mixed refrigerant containing trifluoroiodomethane and has a low GWP, and continuously suppresses high GWP due to deterioration of the refrigerant. provide. SOLUTION: A compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed by the compressor, a decompressor for decompressing the refrigerant condensed by the condenser, and a decompressing refrigerant are evaporated. A refrigerating cycle device including an evaporator, an accumulator 9 that separates droplets from a refrigerant containing droplets evaporated by the evaporator and temporarily stores them, and a dryer that removes water in the refrigerant. Is a mixed refrigerant containing trifluoroiodomethane, the steam pressure at 25 ° C. is 1.1 MPa or more and 1.8 MPa or less, and the compressor drives a compression mechanism unit and a compression mechanism unit in a closed container. It is a closed-type electric compressor that is provided with a motor and a refrigerating machine oil that lubricates a sliding portion, and includes an adsorbent 46 that adsorbs trifluoromethane in an accumulator 9. [Selection diagram] Fig. 3

Description

The present invention relates to a refrigeration cycle device using a refrigerant having a small Global Warming Potential (GWP).

Traditionally, various measures against climate change have been taken internationally to prevent global warming. At the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change (COP21) held in 2015, the Paris Agreement was adopted and long-term goals to be achieved in the future were set. The Paris Agreement aims to keep the global average temperature rise well below 2 ° C compared to before the Industrial Revolution and to pursue efforts to keep it at 1.5 ° C.

In Japan, legislation to prevent global warming is being developed mainly in fields related to fluorine compounds. Regarding the use and management of fluorine-based refrigerants used in refrigeration and air-conditioning equipment, regulated equipment and regulated substances are stipulated in the "Act on the Rational Use of CFCs and the Appropriate Management (CFC Emission Control Act)".

The substances subject to regulation are ozone-destructive substances (mainly fluorine compounds with chlorine or bromine bound) specified in the "Act on the Protection of the Ozone Layer by Regulation of Specified Substances, etc." and "Promotion of Global Warming Countermeasures". Examples include greenhouse gas substances (high GWP substances mainly composed of hydrogen, fluorine and carbon) listed in the "Act on Law".

Currently, GWP, which is an index showing the degree of environmental impact, has been set as a target value by a weighted average for each designated product due to the revision of the Freon Emission Control Law. 750 for home air conditioners by 2018, 750 for store / office air conditioners by 2020, condensin units and stationary refrigeration units (hereinafter abbreviated as refrigerators, etc.) The goal is to reach 1500 by 2025.

Conventionally, R410A [HFC (Hydrofluorocarbon) 32 / HFC125 (50/50% by weight)] and R404A [HFC125 / HFC143a / HFC134a (44/52/4% by weight)] have been used as refrigerants for refrigeration and air conditioners. It was. However, since R410A has a high GWP = 1924 and R404A has a high GWP = 3943, in recent years, replacement with an alternative refrigerant having a lower GWP has been promoted. The GWP of the refrigerant and the combustibility are in a contradictory relationship, and when the GWP of the refrigerant is lowered, the combustibility tends to increase.

As alternative refrigerants, difluoromethane (HFC32) (GWP = 677), 2,3,3,3-tetrafluoropropene (HFO (Hydrofluoroolefin) 1234yf) are available because of their thermophysical properties, low GWP, low toxicity, and low flammability. ) (GWP = 0), 1,3,3,3-tetrafluoropropene (HFO1234ze) (GWP = 1), trifluoroethane (HFO1123) (GWP <1), 3,3,3-trifluoropropene (HFO1243zf) ) (GWP = 0) is known.

Further, a mixed refrigerant of HFO and HFC32, HFC125, HFC134a and the like, hydrocarbon such as propane and propylene, and hydrofluorocarbon which is a low GWP such as monofluoroethane (HFC161) and difluoroethane (HFC152a) are known. Further, a low boiling point compound which is halogenated with iodine, bromine, chlorine or the like to make it nonflammable is also known.

Most household air conditioners are being switched to slightly flammable HFC32 due to amendments to other laws and regulations. In the revision of the Refrigeration Safety Regulations of the High Pressure Gas Safety Act (November 2016), HFC32, HFO1234yf, and HFO1234ze were classified as "inert gas". However, since these refrigerants are slightly flammable, they are also labeled as "specific inert gases." For equipment of 5 refrigeration tons or more, it is necessary to have a ventilation device / equipment structure to prevent the leaked refrigerant from staying, and it is necessary to install a detection / alarm equipment in a place where the leaked refrigerant tends to stay.

Against this background, the replacement of low GWP refrigerants has not progressed in multi-air conditioners (multi-room air conditioners) and refrigerators for buildings that require more freezing capacity, and R410A is still used today. Multi-air conditioners and refrigerators for buildings have a large amount of refrigerant filled and there is a high risk of refrigerant leakage, so it is difficult to use a slightly flammable refrigerant having a low GWP.

On the other hand, as a refrigerant for a refrigerator, a nonflammable mixed refrigerant having a GWP of 1500 or less and containing HFO1234yf and HFO1234ze has attracted attention because of the relationship with the Freon emission suppression method. For example, the development of a refrigerator using R448A (HFC32 / HFC125 / HFC134a / HFO1234ze / HFO1234yf) and R449A (HFC32 / HFC125 / HFC134a / HFO1234yf) is underway. However, since R448A and R449A cannot be made incombustible unless the GWP is kept at about 1100 to 1400, it is necessary to suppress combustibility in order to promote low GWP.

Traditionally, as an international measure to prevent global warming, regulations under the Montreal Protocol have been tightened. Initially, the substances subject to regulation were the specified substances stipulated in Japan's "Act on the Protection of the Ozone Layer by Regulation of Specific Substances, etc." However, at the 28th Montreal Protocol Conference of the Parties (MOP28) held in Kigali, Rwanda in October 2016, regulations were also imposed on CFC substitutes, etc. listed in Japan's "Act on Promotion of Global Warming". It was to be expanded.

In the Kigali revision, the production and consumption of regulated substances will be -10% in 2019, -40% in 2024, -70% in 2029, and -80% in 2034, based on 2011-2013. , It was agreed to be -85% in 2036. On the other hand, until 2024, it is expected that the target value can be achieved by the current Freon emission control law. However, it is expected that it will be difficult to achieve the target value after 2029.

Under such circumstances, a low GWP, nonflammable mixed refrigerant containing trifluoroiodomethane (CF ₃ I) has attracted attention. According to the mixed refrigerant containing trifluoroiodomethane, the refrigerating capacity close to that of R410A used in the current multi air conditioners for buildings can be obtained while suppressing the combustibility of the refrigerant, so that even if there is no major design change, it is not necessary. It is expected that a refrigerating air conditioner with high environmental compatibility will be realized.

Patent Document 1 describes a technique for purifying an etching agent in a thin film manufacturing process and monofluoromethane used as a cleaning agent. In this technique, trifluoromethane (CHF ₃ ) is separated from monofluoromethane by chemical absorption. A treatment solution containing an amide and a base is used for chemical absorption.

Japanese Unexamined Patent Publication No. 2012-121855

When trifluoroiodomethane (CF ₃ I) is mixed with a refrigerant such as difluoromethane (HFC32), combustibility can be suppressed while keeping GWP low. Therefore, it is possible to obtain a refrigerant having a low GWP and low flammability. However, trifluoroiodomethane undergoes a chemical reaction in the presence of water, oxygen, heat, etc. and decomposes to produce trifluoromethane (CHF ₃ ), which is a type of hydrofluorocarbon, hydrogen fluoride, hydrogen iodide, etc. To do.

Refrigerating cycle devices such as refrigerating and air-conditioning devices are provided with various metal materials such as copper pipes, flare nuts made of brass, and joints made of silver wax in a refrigerating cycle through which a refrigerant flows. These metal materials have the potential to catalyze the decomposition of trifluoroiodomethane and the downstream reactions that accompany the decomposition. Further, sliding heat or the like is applied to the refrigerant circulating in the refrigeration cycle, and refrigerating machine oil, which is an organic molecule to which hydrogen atoms are bonded, coexists. Therefore, if the refrigeration cycle apparatus is continuously operated, there is a concern that the refrigerant deteriorates and the concentration of the deterioration reaction product increases in the presence of the catalyst and heat.

Among the deterioration reaction products produced by the decomposition of trifluoroiodomethane, trifluoromethane has a GWP = 12400 and is a substance having a high greenhouse effect. There is a problem that the GWP of the refrigerant increases as the concentration of trifluoromethane increases. In addition, the refrigerating capacity may be adversely affected. Therefore, a technique for suppressing an increase in the concentration of trifluoromethane in the refrigeration cycle is desired.

The technique described in Patent Document 1 chemically absorbs trifluoromethane (CHF ₃ ) into a treatment liquid containing an amide and a base. When such a technique is used in a refrigeration cycle, trifluoroiodomethane itself is also deteriorated. When the sliding heat of the compressor or the like is applied to the mixed refrigerant containing trifluoroiodomethane in the presence of an amide, the concentration of trifluoromethane may rather increase. Further, not only the refrigerant but also the refrigerating machine oil is deteriorated, so that the reliability of the refrigerating cycle apparatus is significantly lowered.

Therefore, the present invention uses a nonflammable mixed refrigerant containing trifluoroiodomethane and a low GWP, and refrigeration with high environmental compatibility and reliability, in which high GWP due to deterioration of the refrigerant is continuously suppressed. It is an object of the present invention to provide a cycle device.

In order to solve the above problems, the refrigerating and air-conditioning cycle device according to the present invention decompresses a compressor that compresses the refrigerant, a condenser that condenses the refrigerant compressed by the compressor, and a refrigerant condensed by the condenser. A decompressor, an evaporator that evaporates the refrigerant decompressed by the decompressor, an accumulator that separates droplets from the refrigerant containing the refrigerant evaporated by the evaporator and temporarily stores them, and moisture in the refrigerant. A refrigerating cycle apparatus including a dryer for removing, wherein the refrigerant is a mixed refrigerant containing trifluoroiodomethane, and the steam pressure at 25 ° C. is 1.1 MPa or more and 1.8 MPa or less, and the compression is performed. The machine is a closed electric compressor in which a compression mechanism portion and a motor for driving the compression mechanism portion are provided in a closed container, and refrigerating machine oil for lubricating the sliding portion is filled. An adsorbent that adsorbs trifluoromethane is provided in the accumulator.

According to the present invention, a nonflammable mixed refrigerant containing trifluoroiodomethane and a low GWP is used, and the high GWP due to the deterioration of the refrigerant is continuously suppressed, and the refrigeration cycle has high environmental compatibility and reliability. The device can be provided.

It is a refrigerating cycle block diagram which shows an example of the multi air conditioner for a building which is a refrigerating cycle apparatus. It is a vertical cross-sectional view which shows an example of a closed type electric compressor. It is a vertical cross-sectional view which shows an example of an accumulator. It is a vertical cross-sectional view which shows an example of a receiver tank.

Hereinafter, the refrigeration cycle apparatus according to the embodiment of the present invention will be described in detail with reference to the drawings. In each of the following figures, common configurations are designated by the same reference numerals and duplicated description will be omitted.

<Refrigeration cycle equipment>
The refrigeration cycle device according to the present embodiment is a device having an ability to cool a cooling target by utilizing a thermodynamic refrigeration cycle formed by a refrigerant. The refrigeration cycle apparatus may be capable of performing a thermal cycle opposite to the refrigeration cycle, as long as it is capable of performing cooling. This refrigeration cycle device can be applied to various refrigeration and air conditioning devices such as an air conditioner and a refrigerator.

The refrigeration cycle apparatus according to the present embodiment includes a compressor that compresses the refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a decompressor that decompresses the refrigerant condensed by the condenser, and a decompressor. It is provided with an evaporator for evaporating the generated refrigerant. As the compressor, a closed electric compressor is used in which a compression mechanism unit and a motor for driving the compression mechanism unit are provided in a closed container, and refrigerating machine oil for lubricating the sliding parts is filled. ..

Further, the refrigeration cycle apparatus according to the present embodiment is an accumulator that separates droplets from a refrigerant containing droplets evaporated by the evaporator and temporarily stores them in addition to these compressors, condensers, decompressors and evaporators. And a dryer for removing the moisture in the refrigerant. In addition to an accumulator and a dryer, this refrigeration cycle device can be provided with a receiver tank for adjusting excess refrigerant.

In the refrigeration cycle apparatus according to the present embodiment, a mixed refrigerant containing trifluoroiodomethane (CF ₃ I) is used as the refrigerant. The accumulator and the receiver tank correspond to a place where the flow velocity of the refrigerant is slow in the refrigeration cycle through which the refrigerant flows, and a place where trifluoromethane (CHF ₃ ) produced by decomposition of trifluoroiodomethane tends to stay.

In the refrigeration cycle apparatus according to the present embodiment, an adsorbent that adsorbs trifluoromethane is installed at such a location. By installing an adsorbent that adsorbs trifluoromethane, the increase in the concentration of trifluoromethane in the refrigeration cycle is suppressed, the increase in GWP due to the deterioration of the refrigerant is continuously suppressed, and the environmental compatibility of the refrigeration cycle equipment is suppressed. And ensure reliability.

Here, the refrigeration cycle apparatus according to the present embodiment and the compressor used in the refrigeration cycle apparatus will be described with reference to specific examples.

FIG. 1 is a refrigeration cycle configuration diagram showing an example of a multi air conditioner for a building, which is a refrigeration cycle device.
The refrigeration cycle device according to the present embodiment can be applied as an air conditioner such as a multi-room air conditioner for buildings as shown in FIG.

As shown in FIG. 1, the building multi air conditioner 100 includes an outdoor unit 1 and indoor units 2a and 2b. In FIG. 1, the building multi air conditioner 100 includes two indoor units 2a and 2b. However, the building multi air conditioner 100 can be provided with an arbitrary number of three or more indoor units (2a, 2b, ...).

The outdoor unit 1 includes a compressor 3, a four-way valve 4, an outdoor heat exchanger (condenser / evaporator) 5, a receiver tank 6, a dryer (dryer) 7, and an outdoor expansion valve (decompressor) 8. The accumulator 9 and the outdoor blower 10 are provided.

The four-way valve 4, the accumulator 9, and the compressor 3 are connected in a closed ring shape via a refrigerant pipe. Further, indoor units 2a and 2b are connected to another connection portion of the four-way valve 4 via a refrigerant pipe. An outdoor heat exchanger 5, a receiver tank 6, a dryer 7, an outdoor expansion valve 8, and indoor units 2a and 2b are connected to the remaining connection portion of the four-way valve 4 via a refrigerant pipe in this order.

These devices and the refrigerant pipes connecting the devices form a refrigeration cycle as a circulation path for circulating the refrigerant between the outdoor unit 1 and the indoor units 2a and 2b. A predetermined refrigerant described later is sealed in the refrigeration cycle. Further, the compressor 3 is filled with a predetermined refrigerating machine oil described later for the purpose of lubrication, sealing of the refrigerant, cooling, and the like.

The compressor 3 is a closed electric compressor, and has a compression mechanism and a motor for driving the compression mechanism built in the closed container. The four-way valve 4 can switch the circulation direction of the refrigerant discharged from the compressor 3 in the refrigeration cycle according to the thermodynamic cycle. The outdoor heat exchanger 5 exchanges heat between the refrigerant and the outside air, and acts as a condenser during the cooling operation and as an evaporator during the heating operation.

The receiver tank 6 is a container for adjusting the excess refrigerant. The gas refrigerant separated from the liquid refrigerant is temporarily stored in the receiver tank 6. Substantially only liquid refrigerant is sent from the receiver tank 6 to the outdoor expansion valve 8. Although the receiver tank 6 is installed in the refrigeration cycle shown in FIG. 1, the receiver tank 6 may not be installed. The receiver tank 6 may not be installed depending on the model of the refrigeration cycle device.

The dryer 7 is a device for removing water in the refrigerant. The dryer 7 shown in FIG. 1 is an in-line type strainer. The inside of the dryer 7 is filled with a desiccant in order to remove water that causes deterioration of the refrigerant and refrigerating machine oil.

As the desiccant, synthetic zeolite having a pore size for adsorbing water, for example, zeolite such as molecular sieve, silica gel, activated alumina and the like can be used. As the desiccant, those having a pore size equal to or smaller than the effective diameter of water and larger than the effective diameter of the refrigerant component, refrigerating machine oil, additives, trifluoromethane and the like are preferable. That is, it is preferable that water is selectively adsorbed and it is difficult to adsorb a refrigerant component larger than water, refrigerating machine oil, additives, trifluoromethane and the like.

In addition, in FIG. 1, the dryer 7 is installed in the bypass in the refrigeration cycle. The bypass is provided between the receiver tank 6 and the outdoor expansion valve 8 in parallel with the mainstream pipe. By installing in such a section, it is prevented that the high temperature refrigerant comes into contact with the desiccant. Further, by installing the bypass, pressure loss due to the dryer 7 and wear / crushing of the desiccant due to the high flow velocity refrigerant are suppressed. However, the dryer 7 may be installed in the mainstream pipe or the like between the receiver tank 6 and the outdoor expansion valve 8. When the dryer 7 is installed in the mainstream pipe, the number of parts constituting the refrigeration cycle can be reduced.

The outdoor expansion valve 8 is composed of, for example, an electronic expansion valve, a temperature expansion valve, or the like, and functions as a decompressor during cooling operation. The accumulator 9 is a device that separates gas and liquid from the refrigerant gas and the liquid refrigerant, and separates the droplets from the refrigerant containing the droplets and temporarily stores the droplets. The outdoor blower 10 is provided to blow outside air to the outdoor heat exchanger 5, and promotes heat exchange between the refrigerant and the outside air.

The indoor units 2a and 2b are provided with indoor heat exchangers (evaporators / condensers) 11a and 11b, indoor expansion valves (decompressors) 12a and 12b, and indoor blowers 13a and 13b, respectively. When the multi air conditioner 100 for a building is provided with two or more indoor units (2a, 2b, ...), Each indoor unit is provided in the same configuration and is provided with a refrigerant pipe so as to form a parallel refrigeration cycle. You can connect.

The indoor heat exchangers 11a and 11b exchange heat between the refrigerant and the indoor air, and act as an evaporator during the cooling operation and as a condenser during the heating operation. The indoor expansion valves 12a and 12b are composed of, for example, an electronic expansion valve, a temperature type expansion valve, and the like, and act as a decompressor during the heating operation. The indoor blowers 13a and 13b are provided to blow indoor air to the indoor heat exchangers 11a and 11b, and promote heat exchange between the refrigerant and the indoor air.

Cooling by the building multi air conditioner 100 is performed on the following principle. The high-temperature and high-pressure refrigerant gas adiabatically compressed by the compressor 3 is sent to the outdoor heat exchanger 5 through the four-way valve 4. Then, the refrigerant gas is cooled by heat exchange with the outside air in the outdoor heat exchanger 5 that acts as a condenser to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant enters the receiver tank 6, and the uncondensed refrigerant gas is separated. Moisture contained in the liquid refrigerant is removed by the dryer 7. The high-pressure liquid refrigerant from which the refrigerant gas is separated is depressurized by the outdoor expansion valve 8 and expands to become a gas-liquid two-phase refrigerant (a low-temperature low-pressure liquid refrigerant containing a small amount of refrigerant gas).

The gas-liquid two-phase refrigerant decompressed by the outdoor expansion valve 8 is sent to the individual indoor heat exchangers 11a and 11b. Then, the indoor heat exchangers 11a and 11b that act as evaporators evaporate by heat exchange with the indoor air to take heat and become a low-temperature low-pressure gas refrigerant. The low-temperature low-pressure gas refrigerant passes through the four-way valve 4 and enters the accumulator 9, and the low-temperature low-pressure liquid refrigerant that has not completely evaporated is separated. The low-temperature low-pressure gas refrigerant from which the liquid refrigerant has been separated returns to the compressor 3. After that, the same cycle is repeated and cooling is continued.

Heating by the multi air conditioner 100 for buildings is performed in a cycle opposite to that during cooling. The high-temperature and high-pressure refrigerant gas adiabatically compressed by the compressor 3 is sent to the individual indoor heat exchangers 11a and 11b by switching the four-way valve 4. Then, the indoor heat exchangers 11a and 11b that act as condensers apply heat to the indoor air, and then the outdoor heat exchanger 5 that acts as an evaporator removes heat from the outside air. Such a similar cycle is repeated to continue heating.

FIG. 2 is a vertical sectional view showing an example of a closed electric compressor.
The refrigeration cycle apparatus according to the present embodiment may include, for example, a scroll-type closed electric compressor as shown in FIG. 2 as a compressor for compressing the refrigerant. The sealed electric compressor can be used as the compressor 3 of the multi air conditioner 100 for buildings shown in FIG.

As shown in FIG. 2, the closed electric compressor 3 has a fixed scroll member 20 having a spiral fixed wrap 20a provided perpendicularly to the end plate, and a spiral shape having substantially the same shape as the fixed wrap 20a. A swivel scroll member 21 having the swivel lap 21a, a frame 22, a crankshaft 23 for swiveling the swivel scroll member 21, a motor 24 for driving the crankshaft 23, and a closed container 25 incorporating these are provided. ing.

The fixed scroll member 20 is bolted to the frame 22. An old dam ring that regulates the rotation of the swivel scroll member 21 is engaged with the swivel scroll member 21 in a slidable state. The swivel scroll member 21 is supported by a swivel bearing. An eccentric pin that drives the swivel scroll member 21 eccentrically is fitted in the swivel bearing.

The fixed scroll member 20 and the swivel scroll member 21 are arranged so as to face each other so that the fixed wrap 20a and the swivel wrap 21a mesh with each other, and form a compression mechanism portion for compressing the refrigerant. A compression chamber 26 is formed between the fixed wrap 20a and the swirling wrap 21a.

The crankshaft 23 is supported in a state in which the spindle portion is rotatable by the main bearing 30 which is a rolling bearing. Further, the sub-shaft portion is rotatably supported by the sub-bearing 31 which is a rolling bearing. A balance weight is attached to the middle portion of the crankshaft 23.

The rotation of the crankshaft 23 is driven by the motor 24 at a constant rotation speed or a rotation speed corresponding to a voltage controlled by an inverter. When the crankshaft 23 is rotated by the operation of the motor 24, the swivel scroll member 21 is eccentrically swiveled with respect to the fixed scroll member 20.

In the closed electric compressor 3, a suction pipe for sucking the refrigerant from the refrigerating cycle as a circulation path of the refrigerant is provided above the closed container 25. The suction pipe communicates with a suction port to the compression chamber 26 provided on the outside of the fixed scroll member 20. When the swivel scroll member 21 swivels, the outermost compression chamber 26 moves toward the center of the compression mechanism while gradually reducing its volume. Along with this operation, the refrigerant introduced into the compression chamber 26 through the suction port is continuously compressed.

When the compression chamber 26 moves to the center of the compression mechanism portion, it communicates with the discharge port 27 provided so as to penetrate the fixed scroll member 20. Inside the closed container 25, there are an upper space and a lower space with the fixed scroll member 20 interposed therebetween. The refrigerant gas compressed in the compression chamber 26 is discharged from the discharge port 27 into the upper space inside the closed container 25. The refrigerant gas released into the upper space moves to the lower space through a plurality of discharge gas passages penetrating the fixed scroll member 20. Then, it is discharged from the discharge pipe 28 penetrating the closed container 25 provided in the lower space into the refrigeration cycle as the circulation path of the refrigerant.

In the closed container 25, an oil reservoir 32 for accumulating refrigerating machine oil is provided below the motor 24. The refrigerating machine oil in the oil reservoir 32 is sucked by the pressure difference during the operation of the compression mechanism. Then, through the oil hole 29 provided in the crankshaft 23, the sliding portion between the swivel scroll member 21 and the crankshaft 23, the rolling bearing of the main bearing 30 that supports the main shaft portion of the crankshaft 23, and the crankshaft. It is supplied to the rolling bearing or the like of the auxiliary bearing 31 that supports the auxiliary shaft portion of 23.

In FIG. 2, the sealed electric compressor 3 is a scroll compressor, but the compressor constituting the refrigeration cycle device includes, for example, a screw compressor and a rotary compressor in addition to the scroll compressor. , Twin rotary compressor, two-stage compression rotary compressor, swing type compressor in which rollers and vanes are integrated, and the like can also be used.

FIG. 3 is a vertical sectional view showing an example of an accumulator.
As shown in FIG. 3, the accumulator 9 includes a container 40 constituting the main body, an inflow pipe 41 for inflowing refrigerant into the container 40, an outflow pipe 42 for flowing out refrigerant gas from the container 40, and a mixed liquid 43. A partition member 45 supported on the upper part of the container 40 so as to be located above the liquid level can be provided.

The accumulator 9 is a device for separating droplets from the gas refrigerant flowing into the container 40 and temporarily storing the droplets in the container 40. In FIG. 3, the container 40 is provided in a bottomed tubular shape. The upper part of the container 40 is sealed by a lid member. An inflow pipe 41 and an outflow pipe 42 are attached to the lid member of the container 40 so as to penetrate the inside and outside of the container 40.

The inflow pipe 41 is provided as an L-shaped pipe in FIG. One end of the inflow pipe 41 is connected to the outlet side of the four-way valve 4 via a pipe. The inflow pipe 41 extends from above the container 40 through the lid member into the container 40, and is bent sideways at the upper part in the container 40. The other end of the inflow pipe 41 is open to the upper part of the container 40 facing sideways. At the other end of the inflow pipe 41, an inflow port 41a for allowing the refrigerant to flow into the container 40 is formed as an opening.

In FIG. 3, the outflow pipe 42 is provided as a U-shaped pipe having different left and right lengths. One end of the outflow pipe 42 opens upward in the upper part of the container 40. The outflow pipe 42 extends from the upper part of the container 40 to the lower part of the container 40, bends at the lower part of the container 40, and extends from the lower part of the container 40 toward the upper side of the container 40 through the lid member. The other end of the outflow pipe 42 is connected to the suction side of the compressor 3 via a pipe.

The mixed solution 43 is temporarily stored in the container 40 during the operation of the refrigeration cycle. The mixture 43 is a liquid in which a liquid liquid refrigerant and refrigerating machine oil are mixed, and is derived from droplets separated from the gas refrigerant. An intermediate portion of the outflow pipe 42 is located at the lower part of the container 40. An oil return hole 44 is provided in the middle portion of the outflow pipe 42 at a position where the mixture is immersed in the mixed liquid 43.

During the operation of the refrigeration cycle, the gas refrigerant generated in the indoor heat exchangers 11a and 11b flows into the container 40 through the inflow pipe 41. The gas refrigerant includes droplets of the liquid refrigerant that could not be completely evaporated by the indoor heat exchangers 11a and 11b, and droplets of refrigerating machine oil. When such a gas refrigerant flows into the container 40, the liquid refrigerant and the refrigerating machine oil are separated from the gas refrigerant by the difference in specific gravity. By separating the liquid refrigerant, seizure due to poor compression or insufficient lubrication in the compressor 3 is prevented.

When the liquid refrigerant or refrigerating machine oil separated from the gas refrigerant flows into the container 40, it flows down to the bottom of the container 40 and is temporarily stored in the container 40. On the other hand, the gas refrigerant enters the outflow pipe 42 from the gas phase portion in the container 40. The gas refrigerant is sucked into the compressor 3 from the other end of the outflow pipe 42. While the gas refrigerant is sucked into the compressor 3, a part of the mixed liquid 43 stored in the container 40 is also sucked through the oil return hole 44. Lubrication is performed in the compressor 3 by sucking the refrigerating machine oil through the oil return hole 44.

Note that FIG. 3 shows an example in which the outflow pipe 42 is provided with the oil return hole 44. However, in addition to the oil return hole 44, the outflow pipe 42 is provided with another oil return hole for adjusting the dryness of the refrigerant and a pressure equalizing hole for preventing overflow at the start of the compressor 3. You can also do it. The additional oil return hole can be provided, for example, in a straight pipe portion having a height located in the liquid phase portion above the oil return hole 44. The pressure equalizing hole can be provided in a straight pipe portion or the like having a height located in the gas phase portion above the outflow pipe 42.

As shown in FIG. 3, the adsorbent 46 that adsorbs trifluoromethane (CHF ₃ ) can be placed in the container 40 of the accumulator 9. The adsorbent 46 is preferably placed in the gas phase portion of the accumulator 9, and more preferably placed above the inflow port 41a. Trifluoromethane is a gas at the operating temperature of the refrigerant. Further, the temperature of the upper part of the accumulator 9 is relatively low, and the amount of the refrigerant component and the refrigerating machine oil is small. Therefore, with such an arrangement, trifluoromethane separated from the liquid refrigerant and diffused in the gas phase portion can be efficiently adsorbed.

In FIG. 3, the adsorbent 46 is installed on the partition member 45. The partition member 45 is provided in a mesh shape so that gas can pass through, and is attached substantially horizontally so as to partition the upper part of the container 40 vertically. However, the partition member 45 may be provided in a perforated shape having one or more through holes, a porous shape having a large number of through holes, or the like as long as the air permeability and the strength as a member are secured. Examples of the porous partition member 45 include a metal lath, a wire lath, a punching metal, and the like.

Such a partition member 45 can be mounted in the container 40 for the installation of the adsorbent 46. The partition member 45 may be fixed to the container 40 or may be detachably attached to the container 40. The shape of the partition member 45 is not particularly limited. The partition member 45 may be provided in a shape that partitions the entire cross section of the container 40 vertically, or may be provided in a shape that partitions a part of the cross section vertically.

Examples of the shape that partitions the entire cross section of the partition member 45 up and down include a shape that also functions as a filter, such as a porous shape. Further, as a shape for partitioning a part of the cross section vertically, for example, a shelf shape supported by a wall surface, a basket shape, or the like can be mentioned. In the case of such a shape, the partition member 45 may be formed of a non-perforated plate or the like instead of being perforated or porous.

FIG. 4 is a vertical cross-sectional view showing an example of the receiver tank.
As shown in FIG. 4, the receiver tank 6 includes a container 50 constituting the main body, an inflow pipe 51 for inflowing refrigerant into the container 50, an outflow pipe 52 for flowing out refrigerant gas from the container 50, and a mixed liquid 53. A partition member 54 supported on the upper part of the container 50 so as to be located above the liquid level of the container 50 can be provided.

The receiver tank 6 is a device for adjusting the surplus refrigerant, temporarily stores the liquid refrigerant flowing into the container 50 in the container 50, and limits the liquid refrigerant from which the gas refrigerant is separated to the outdoor expansion valve 8. Supply. In FIG. 4, the container 50 is provided in a bottomed tubular shape. The upper part of the container 50 is sealed by a lid member. An inflow pipe 51 and an outflow pipe 52 are attached to the lid member of the container 50 so as to penetrate the inside and outside of the container 50.

The inflow pipe 51 is provided as an L-shaped pipe in FIG. 4, and is attached to the upper part of the container 50 in an inverted L-shape with the opening facing downward. One end of the inflow pipe 51 is connected to the outlet side of the outdoor heat exchanger 5 via a pipe. The inflow pipe 51 extends from above the container 50 to the lower part inside the container 50 through the lid member. The other end of the inflow pipe 51 opens downward in the lower part of the container 50.

In FIG. 4, the outflow pipe 52 is provided as an L-shaped pipe like the inflow pipe 51, and is attached to the upper part of the container 50 in an inverted L-shape with the opening facing downward, in contrast to the inflow pipe 51. ing. One end of the outflow pipe 52 opens downward in the lower part of the container 40. The outflow pipe 52 extends from the lower part of the container 50 toward the upper side of the container 50 through the lid member. The other end of the outflow pipe 52 is connected to the suction side of the outdoor expansion valve 8 via a pipe.

The liquid refrigerant 53 is temporarily stored in the container 50 during the operation of the refrigeration cycle. By storing a part of the liquid refrigerant 53 as a surplus refrigerant, the amount of the refrigerant supplied toward the outdoor expansion valve 8 is adjusted. The liquid refrigerant 53 is supplied toward the outdoor expansion valve 8 after the uncondensed refrigerant gas is separated in the container 50.

As shown in FIG. 4, the adsorbent 55 that adsorbs trifluoromethane (CHF ₃ ) can be arranged in the container 50 of the receiver tank 6. The adsorbent 55 is preferably arranged in the gas phase portion of the receiver tank 6, and is preferably arranged above the maximum liquid level of the excess refrigerant stored in the receiver tank 6. Trifluoromethane is a gas at the operating temperature of the refrigerant. Further, the temperature of the upper part of the receiver tank 6 is relatively low, and the amount of the refrigerant component and the refrigerating machine oil is small. Therefore, with such an arrangement, trifluoromethane separated from the liquid refrigerant and diffused in the gas phase portion can be efficiently adsorbed.

In FIG. 4, the adsorbent 55 is installed on the partition member 54. The partition member 54 is provided in a mesh shape so that gas can pass through, and is attached substantially horizontally so as to partition the upper part of the container 50 vertically. However, like the partition member 45, the partition member 54 is provided in a perforated shape having one or more through holes, a porous shape having a large number of through holes, or the like as long as air permeability and strength as a member are secured. May be done.

Such a partition member 54 can be installed in the container 50 for the installation of the adsorbent 55. The partition member 54 may be fixed to the container 50 or may be detachably attached to the container 50. The shape of the partition member 54 is not particularly limited. Similar to the partition member 45, the partition member 54 may be provided in a shape that partitions the entire cross section of the container 50 vertically, or may be provided in a shape that partitions a part of the cross section vertically.

Examples of the shape that partitions the entire cross section of the partition member 54 vertically include a shape that also functions as a filter, such as a porous shape. Further, as a shape for partitioning a part of the cross section vertically, for example, a shelf shape supported by a wall surface, a basket shape, or the like can be mentioned. In the case of such a shape, the partition member 54 may be formed of a non-perforated plate or the like instead of being perforated or porous.

The refrigeration cycle apparatus according to the present embodiment may be provided with an adsorbent for adsorbing trifluoromethane (CHF ₃ ) only in the accumulator 9 as shown in FIG. 3, or only in the receiver tank 6 as shown in FIG. It may be provided, or it may be provided in both the accumulator 9 and the receiver tank 6.

However, from the viewpoint of efficient adsorption, the adsorbent that adsorbs trifluoromethane is preferably arranged at a place where the temperature is low, and is preferably provided at least in the accumulator 9. The accumulator 9 and the receiver tank 6 are not particularly limited in the shape of the container, the shape of the inflow pipe and the outflow pipe, the connection position of the inflow pipe and the outflow pipe, and the like.

Hereinafter, the details of the refrigerant and the refrigerating machine oil used in the refrigerating cycle apparatus according to the present embodiment will be described.

<Refrigerant>
As the refrigerant of the refrigeration cycle apparatus, a mixed refrigerant containing trifluoroiodomethane (CF ₃ I) is used. As the refrigerant, it is preferable to use a mixed refrigerant containing difluoromethane (HFC32), pentafluoroethane (HFC125) and trifluoroiodomethane (CF ₃ I). The mixed refrigerant may contain only these three components as a refrigerant component, or may contain other refrigerant components in addition to these three components. Additives may or may not be added to the mixed refrigerant.

Of the refrigerant components, difluoromethane is mainly used to ensure high refrigerating capacity and energy efficiency. Pentafluoroethane is also mainly used to reduce the temperature gradient. In addition, trifluoroiodomethane is mainly used to reduce the GWP and combustibility of the mixed refrigerant itself. In the present specification, the temperature gradient means the temperature difference between the start temperature and the end temperature of the phase change (evaporation / condensation) of the refrigerant.

According to the mixed refrigerant containing these three components, excellent refrigerating capacity, energy efficiency, small temperature gradient, low GWP and low combustibility can be obtained. Therefore, by using such a mixed refrigerant, it is possible to obtain a refrigeration cycle device having high safety and environmental compatibility, and excellent refrigerating capacity and power efficiency.

The refrigerant of the refrigeration cycle apparatus has a global warming potential (GWP) of 750 or less, preferably 500 or less, and more preferably 150 or less. When the GWP is 750 or less, the refrigerant has excellent environmental performance, is highly compliant with legal regulations, and can be used not only in refrigerators but also in air conditioners.

The GWP of the refrigerant can be adjusted to 750 or less by changing the composition ratio of the mixed refrigerant. Difluoromethane (HFC32) has GWP = 677, pentafluoroethane (HFC125) has GWP = 3500, and trifluoroiodomethane (CF ₃ I) has GWP = 0.4.

The refrigerant of the refrigeration cycle apparatus preferably has a saturated vapor pressure of 1.1 MPa or more and 1.8 MPa or less at 25 ° C. When the saturated vapor pressure is in this range, it is equivalent to the conventional general refrigeration cycle device using R32, R410A, R404A, etc., without making major changes in the system, design, construction method of refrigerant piping, etc. Refrigerating capacity, refrigerant encapsulation, etc. can be obtained.

The saturated vapor pressure of the refrigerant can be adjusted to 1.1 MPa or more and 1.8 MPa or less by changing the composition ratio of the mixed refrigerant. The saturated vapor pressure at 25 ° C. is difluoromethane (HFC32): about 1.69 MPa, pentafluoroethane (HFC125): about 1.38 MPa, and trifluoroiodomethane (CF ₃ I): about 0.5 MPa.

Difluoromethane (HFC32) is preferably 10% by weight or more, more preferably 20% by weight or more and 80% by weight or less, still more preferably 20% by weight or more and 60% by weight or less, and particularly preferably 30% by weight as the refrigerant of the refrigeration cycle apparatus. % Or more and 50% by weight or less. Further, pentafluoroethane (HFC125) is preferably 5% by weight or more and 25% by weight or less. Further, trifluoroiodomethane (CF ₃ I) is preferably 30% by weight or more and 60% by weight or less.

With such a composition, a mixed refrigerant containing slightly flammable difluoromethane is quasi-azeotroped with pentafluoroethane, reduced to low GWP with trifluoroiodomethane, and a small amount of pentafluoroethane and trifluoroiodo. It can be sufficiently made nonflammable with methane.

In addition to the above three components, the refrigerant of the refrigeration cycle apparatus may contain CO ₂ , hydrocarbons, ether, fluoroether, fluoroalkene, HFC, HFO, HClFO, HBrFO and the like as other refrigerant components.

In addition, "HFC" indicates hydrofluorocarbon. "HFO" is a hydrofluoroolefin composed of a carbon atom, a fluorine atom and a hydrogen atom, and has at least one carbon-carbon double bond. A "HClFO" consists of a carbon atom, a chlorine atom, a fluorine atom and a hydrogen atom and has at least one carbon-carbon double bond. "HBrFO" consists of a carbon atom, a bromine atom, a fluorine atom and a hydrogen atom, and has at least one carbon-carbon double bond.

Examples of HFC include difluoromethane (HFC32), pentafluoroethane (HFC125), 1,1,2,2-tetrafluoroethane (HFC134), 1,1,1,2-tetrafluoroethane (HFC134a), and trifluoroethane. (HFC143a), difluoroethane (HFC152a), 1,1,1,2,3,3,3-heptafluoropropane (HFC227ea), 1,1,1,3,3,3-hexafluoropropane (HFC236fa), 1 , 1,1,3,3-pentafluoropropane (HFC245fa), 1,1,1,3,3-pentafluoroethane (HFC365mfc) are exemplified.

Examples of fluoroalkenes include fluoroethane, fluoropropene, fluorobutene, chlorofluoroethane, chlorofluoropropene, and chlorofluorobutene. Examples of fluoropropene include 3,3,3-trifluoropropene (HFO1243zf), 1,3,3,3-tetrafluoropropene (HFO1234ze), 2,3,3,3-tetrafluoropropene (HFO1234yf), and HFO1225. Illustrated. Examples of fluorobutene include C ₄ H ₄ F ₄ (HFO 1354), C ₄ H ₃ F ₅ (HFO 1345), and C ₄ H ₂ F ₆ (HFO 1336).

The chlorofluorohydrocarbons _{ethene, C 2 F 3 Cl (CTFE} ) are exemplified. Examples of chlorofluoropropene include 2-chloro-3,3,3-trifluoro-1-propene (HCFO1233xf) and 1-chloro-3,3,3-trifluoro-1-propene (HCFO1233zd).

<Refrigerator oil>
As the refrigerating machine oil of the refrigerating cycle apparatus, polyol ester oil (POE) or polyvinyl ether oil (PVE) can be used.

The polyol ester oil is obtained by a condensation reaction of a polyhydric alcohol and a monovalent fatty acid. Examples of the polyhydric alcohol include neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and the like. Examples of monovalent fatty acids include n-pentanoic acid, n-hexane acid, n-heptane acid, n-octanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, and 2-ethylhexanoic acid. Examples thereof include isooctanoic acid, 3,5,5-trimethylhexanoic acid and the like. As the polyhydric alcohol or monovalent fatty acid, one type may be used, or a plurality of types may be used.

As the polyvinyl ether oil, a polymer of alkoxyvinyl such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether is used.

As the refrigerating machine oil of the refrigerating cycle apparatus, polyol ester oil is preferable. Polyvinyl ether oil tends to produce trifluoromethane (CHF ₃ ) when heated in the presence of trifluoroiodomethane (CF ₃ I). Since the temperature around the sliding portion of the compressor and the vicinity of the discharge port becomes high, when polyvinyl ether oil is used, the need for an additive for preventing the deterioration of trifluoroiodomethane increases.

On the other hand, when polyol ester oil is used, the performance as refrigerating machine oil can be ensured regardless of the presence or absence of such additives. Further, since the polyol ester oil has a characteristic that the oil film formed on the sliding surface is hard to break, good lubricity can be obtained regardless of the presence or absence of an extreme pressure agent such as tricresyl phosphate.

As the polyol ester oil, a pentaerythritol-based compound represented by the following chemical formula (1), a dipentaerythritol-based compound represented by the following chemical formula (2), or a mixture thereof is preferable. [However, in the chemical formulas (1) and (2), R ¹ represents an alkyl group having 4 to 9 carbon atoms, and may be the same as or different from each other. ]

R ¹ may be either a linear alkyl group or a branched alkyl group. Specific examples of R ¹ include n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl group, 3-pentyl group, tert-pentyl group, neopentyl group. Examples include a group, a 1-ethylpentyl group, an isohexyl group, a 2-ethylhexyl group and the like.

Pentaerythritol-based compound represented by Formula (1), and, dipentaerythritol based compound represented by the following chemical formula (2) as R ^1, it is preferred to have only a branched alkyl group. When substituted with a branched alkyl group, the ester group is less likely to react with water or the like mixed in the refrigeration cycle, so that refrigerating machine oil that is less likely to deteriorate can be obtained.

In addition to polyol ester oil, polyalkylene glycol oil, paraffin-based mineral oil, naphthen-based mineral oil, poly-α-olefin oil, soft alkylbenzene oil, and the like are also known as general refrigerating machine oils. However, when these oils are used in combination with a mixed refrigerant containing trifluoroiodomethane (CF ₃ I), it is difficult to secure sufficient thermal stability and chemical stability, so these oils are used in combination with the above-mentioned mixed refrigerant. Not suitable as refrigerating machine oil.

The refrigerating machine oil of the refrigerating cycle apparatus preferably has a kinematic viscosity at 40 ° C. of 22 mm ² / s or more and 84 mm ² / s or less. With such kinematic viscosity, it can be sufficiently compatible with the refrigerant even at a low temperature, so that it can be used without any problem in various types of closed electric compressors. Regardless of the type of compressor, the lubricity of the sliding portion of the compressor and the airtightness of the compression chamber can be appropriately ensured.

The kinematic viscosity of the refrigerating machine oil can be adjusted mainly by changing the composition of the polyol ester oil. The kinematic viscosity of refrigerating machine oil can be measured based on standards such as ISO (International Organization for Standardization) 3104, ASTM (American Society for Testing and Materials) D445, D7042 and the like.

It is preferable that the refrigerating machine oil of the refrigerating cycle apparatus has a water content of 300 ppm by weight or less in a state of being sealed together with the refrigerant in the refrigerating cycle. Generally, the water content of refrigerating machine oil is reduced during production. However, water may be mixed in the refrigerating machine oil when the compressor is filled, or may enter the refrigerating cycle when the refrigerating cycle device is manufactured. Such moisture is mainly localized in the refrigerating machine oil phase, not in the refrigerant phase, during operation of the refrigeration cycle apparatus.

When the water content of the refrigerating machine oil is reduced to 300 ppm by weight or less, the reaction amount of the water content with trifluoroiodomethane (CF ₃ I) or the refrigerating machine oil becomes extremely small, so that the decomposition of trifluoroiodomethane and the refrigerating machine oil Deterioration is greatly suppressed. As a result, the amount of trifluoromethane (CHF ₃ ) produced is also suppressed. Since the total amount of trifluoromethane produced can be suppressed and the sustainability of the adsorbent can be improved, deterioration of the mixed refrigerant itself and deterioration of refrigerating machine oil can be suppressed for a long period of time.

The water content of the refrigerating machine oil is more preferably 200 ppm by weight or less, further preferably 150 ppm by weight or less, and particularly preferably 100 ppm by weight or less in a state of being sealed together with the refrigerant in the refrigeration cycle. As the water content of the refrigerating machine oil is reduced, the deterioration of the mixed refrigerant itself and the deterioration of the refrigerating machine oil can be continuously suppressed.

The water content of the refrigerating machine oil is, for example, the drying process of the refrigerating machine oil, the adjustment of the atmosphere at the time of filling the refrigerating machine oil, the degree of decompression (vacuum degree, etc.) of the vacuum applied to the refrigerating cycle at the time of filling the refrigerating machine oil, and the refrigeration cycle. It can be reduced by installing a dryer / desiccant inside. The means for reducing the amount of water may be used in combination as appropriate.

The water content of the refrigerating machine oil can be measured, for example, by collecting the refrigerating machine oil compatible with the refrigerant from within the refrigerating cycle and using the Karl Fischer titration method. The water content (moisture content in oil) can be measured according to JIS K 2275-3: 2015 "Crude oil and petroleum products-How to obtain water content-Part 3: Karl Fischer titration method".

The refrigerating machine oil of the refrigerating cycle apparatus preferably has a critical melting temperature on the low temperature side of −10 ° C. or lower with the mixed refrigerant containing the above three components. When the critical melting temperature on the low temperature side is −10 ° C. or lower, the refrigerating machine oil and the refrigerant have sufficient compatibility, so that it is possible to prevent the refrigerating machine oil and the refrigerant from separating into two layers during the refrigeration cycle. Since the amount of refrigerating machine oil returned to the compressor is improved, the lubricity of the sliding portion in the compressor, the sealing property of the refrigerant, the cooling property of the sliding portion, and the like can be appropriately maintained.

The critical melting temperature on the low temperature side can be adjusted mainly by changing the composition of the refrigerating machine oil. The critical melting temperature on the low temperature side can be measured according to the compatibility test method specified in JIS K 2211. Refrigerator oil and refrigerant are sealed in a pressure-resistant glass container, and the contents are observed by changing the temperature. If the content is cloudy, the solution is separated into two layers, and if the content is transparent, it can be determined that the solution is compatible. The temperature at which the solution separates into two layers can be determined as the low temperature side critical dissolution temperature.

The refrigerating machine oil of the refrigerating cycle apparatus can contain, as an additive, a lubricity improver, an antioxidant, a stabilizer, an acid scavenger, a defoaming agent, a metal inactivating agent and the like. In particular, from the viewpoint of preventing corrosion of the inner surface of the copper pipe, it is desirable to add a metal inactivating agent such as benzotriazole.

Examples of the lubricity improver include extreme pressure agents consisting of thermochemically stable tertiary phosphates, for example, tricresyl phosphate, triphenyl phosphate, trixylenyl phosphate, cresil diphenyl phosphate, 2-ethylhexyl diphenyl phosphate. , Tris (2-ethylhexyl) phosphate and the like can be used.

When added as an additive, the extreme pressure agent is preferably 0.1% by mass or more and 2.0% by mass or less with respect to the refrigerating machine oil. However, the polyol ester oil has good lubricity without adding an extreme pressure agent. In addition, phosphoric acid esters such as tertiary phosphates are easily decomposed in the presence of deterioration factors generated by the decomposition of trifluoroiodomethane (CF ₃ I). Therefore, when polyol ester oil is used as the refrigerating machine oil, it is not necessary to add an extreme pressure agent.

As the antioxidant, for example, a phenolic antioxidant such as DBPC (2,6-di-t-butyl-p-cresol) can be used. In general, it can be said that the environment in which antioxidants are not easily consumed in refrigerating machine oil. However, when a mixed refrigerant containing trifluoroiodomethane (CF ₃ I) is used, iodic acid (HIO ₃ ) or the like acting as an oxidizing agent is produced along with the decomposition of trifluoroiodomethane. Therefore, it is preferable to add an antioxidant to the refrigerating machine oil. The amount of the antioxidant is preferably 0.1% by mass or more and 21.0% by mass or less with respect to the refrigerating machine oil.

As the acid scavenger, for example, an alicyclic epoxy compound, an aliphatic epoxy compound, a monoterpene compound and the like can be used. The alicyclic epoxy compound remains for a long period of time in the refrigeration cycle and exhibits an action of suppressing an increase in the total acid value. Since the aliphatic epoxy compound reacts with water at a low temperature, the water contained in the refrigerating machine oil can be quickly captured at the initial stage of operation of the refrigerating cycle apparatus. In addition, acidic substances generated by the decomposition of trifluoroiodomethane (CF ₃ I) can be efficiently captured.

Examples of the alicyclic epoxy compound include 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis (3,4-epoxycyclohexyl). Methyl) adipate, exo-2,3-epoxynorbornane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (7-oxabicyclo [4.1.0] hept-3-yl)- Spiro (1,3-dioxane-5,3'-[7] oxabicyclo [4.1.0] heptane, 4- (1'-methylepoxyethyl) -1,2-epoxy-2-methylcyclohexane, 4 -Epoxy ethyl-1,2-epoxycyclohexane and the like can be mentioned.

As the alicyclic epoxy compound, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate represented by the following chemical formula (3) is particularly preferable.

Examples of the aliphatic epoxy compound include an alkyl glycidyl ester compound and an alkyl glycidyl ether compound.

Examples of the alkyl glycidyl ester compound include compounds represented by the following chemical formula (4). [However, in the chemical formula (4), R ² represents an alkyl group having 4 to 12 carbon atoms. ]

Examples of the alkyl glycidyl ether compound include compounds represented by the following chemical formula (5). [However, in the chemical formula (5), R ³ represents an alkyl group having 4 to 12 carbon atoms. ]

R ² and R ³ may be either a linear alkyl group or a branched alkyl group. Specific examples of R ² and R ³ include n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl group, 3-pentyl group, and tert-pentyl. Examples thereof include a group, a neo-pentyl group, a 1-ethylpentyl group, an isohexyl group, a 2-ethylhexyl group and the like.

Examples of the monoterpene compound include a monoterpene monoterpene, a polycyclic monoterpene, and an acyclic monoterpene. As the monoterpene compound, a monocyclic monoterpene is preferable. Examples of the monoterpene monoterpene include limonene, α-pinene, β-pinene, γ-terpinene and the like.

The acid scavenger is preferably 0.1% by mass or more and 2.0% by mass or less with respect to the refrigerating machine oil.

Next, the details of the adsorbent that adsorbs trifluoromethane (CHF ₃ ) used in the refrigeration cycle apparatus according to the present embodiment will be described.

<Adsorbent>
As the adsorbent, for example, a porous material having pores or polarity capable of adsorbing trifluoromethane (CHF ₃ ) can be used. The adsorbent preferably has a pore size equal to or smaller than the effective diameter of trifluoromethane and larger than the effective diameter of a refrigerant component such as trifluoroiodomethane, refrigerating machine oil, or an additive. That is, it is preferable that trifluoromethane is selectively adsorbed and it is difficult to adsorb a refrigerant component such as trifluoroiodomethane, which is larger than trifluoromethane, refrigerating machine oil, additives and the like.

The form of the adsorbent may be any of powder, lump, spherical, plate, scaly, fibrous, monolithic and the like. For example, the adsorbent in the form of powder can be stored in an exterior body made of a non-woven fabric, a resin net, a metal net, a breathable film, or the like, and installed in a refrigeration cycle. Further, the adsorbent may contain a binder, a carrier and the like in addition to the active ingredient that adsorbs trifluoromethane.

Specific examples of the adsorbent include aluminum oxide (Al ₂ O ₃ ), silica alumina, activated carbon, zeolites such as molecular sieve 5A and XH-10. Examples of aluminum oxide include α-alumina and γ-alumina (activated alumina). The aluminum oxide may be either synthetic alumina obtained by a Bayer method, another thermal decomposition method, or the like, sintered alumina (alumina ceramics), or the like. As the adsorbent, one type may be used, or a plurality of types may be used.

As the adsorbent, aluminum oxide is preferable, and activated alumina is particularly preferable. Activated alumina having a predetermined pore size has a high ability to selectively adsorb trifluoromethane (CHF ₃ ). On the other hand, a trace amount of water contained in the mixed refrigerant can be selectively removed by a dryer on the refrigeration cycle. Therefore, if activated alumina having an appropriate pore size is used as the adsorbent, trifluoromethane in the refrigeration cycle can be selectively and efficiently removed.

Generally, as the form of activated alumina, powdery, lumpy, spherical and the like are widely known. The central particle size of general activated alumina is about 1 μm to 10 mm. As the adsorbent, such an appropriate activated alumina can be used. The activated alumina used as the adsorbent is not particularly limited in form and particle size, may be commercially available, or is classified so as to have a predetermined pore distribution. You may.

The pore size of the adsorbent is preferably 0.5 to 1.0 nm, more preferably 0.6 to 0.9 nm, from the viewpoint of selectively adsorbing trifluoromethane (CHF ₃ ). The specific surface area of the adsorbent is preferably more than 100 m ² / g, more preferably 150 m ² / g or more. The pore volume of the adsorbent is preferably 0.3 cm ³ / g or more. As the adsorbent such as activated alumina has a larger specific surface area and pore volume, the amount of adsorbed adsorbent per unit weight increases, so that trifluoromethane in the refrigeration cycle can be efficiently and continuously removed. ..

The specific surface area and pore volume of the adsorbent can be determined by the BET 1-point method. The BET method is a method of obtaining the amount of gas adsorbed using the BET formula that expresses the relationship between the amount of adsorbed gas at equilibrium and the pressure based on the adsorption of gas in the monolayer on the surface of the sample. In the BET 1-point method, the BET equation is approximated on the assumption that the condensation coefficient is significantly larger than 1, and one measurement result is substituted into the approximate equation for calculation.

Further, in the BET method, assuming that the pressure at the time of adsorption is near the saturated vapor pressure, it is possible to utilize the phenomenon that the gas adsorbed in the pores becomes a liquid phase due to the capillary condensation phenomenon. Therefore, by substituting the amount of gas adsorbed into the Kelvin relational expression, not only the specific surface area but also the pore distribution can be obtained. As the adsorbed gas for measurement, nitrogen, argon or the like can be used.

The adsorbent is preferably pretreated in order to improve the activity of the surface. For example, by putting the adsorbent in a vacuum constant temperature bath at 220 ° C. for 5 hours, gas molecules and water adsorbed on the surface can be removed, and the adsorptivity of R23 to the surface of the adsorbent can be improved. The pretreatment temperature is preferably 150 ° C. to 300 ° C. or lower. The adsorbent after the pretreatment is stored in a dry desiccator or the like.

According to the refrigeration cycle apparatus according to the present embodiment described above, a mixed refrigerant containing trifluoroiodomethane (CF ₃ I) is used as the refrigerant, but adsorption that adsorbs trifluoromethane (CHF ₃ ) in the gas phase portion in the refrigeration cycle. Since the agent is installed, it is possible to efficiently and continuously suppress an increase in the concentration of trifluoromethane due to deterioration of the refrigerant. Even when the operation of the refrigeration cycle apparatus is continued, the concentration of trifluoromethane is suppressed, so that it is possible to prevent the mixed refrigerant from becoming high GWP. Further, since the dryer is provided on the refrigeration cycle, the decomposition of trifluoroiodomethane itself that produces trifluoromethane and the deterioration of refrigerating machine oil can be continuously suppressed. Since the adsorbent that adsorbs trifluoromethane and the desiccant used in the dryer are appropriately arranged on the refrigeration cycle, it is possible to efficiently adsorb each adsorption target by utilizing the individual adsorption capacity. For example, a desiccant having an effective diameter of an adsorption target equal to or less than water and an adsorbent having an effective diameter of an adsorption target equal to or less than trifluoromethane are used in combination to reduce competitive adsorption between water and trifluoromethane. be able to. Therefore, it is possible to appropriately maintain the performance and safety of the refrigeration cycle device for a long period of time, and to provide a refrigeration cycle device having high environmental compatibility and reliability.

Although the embodiment of the refrigeration cycle apparatus according to the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are included as long as it does not deviate from the technical scope. For example, the embodiments described above are not necessarily limited to those having all the configurations described. In addition, it is possible to replace a part of the configuration of a certain embodiment with another configuration, or to add another configuration to the configuration of a certain embodiment. It is also possible to add other configurations, delete configurations, and replace configurations for a part of the configurations of one embodiment.

For example, in the above-described embodiment, a multi air conditioner for a building is shown as a specific example of the refrigeration cycle device, but the refrigeration cycle device according to the present invention is applied to a room air conditioner or a package air conditioner including one indoor unit. May be good. Further, the refrigerating cycle device according to the present invention may be applied to a refrigerator, a freezer, a showcase with a built-in refrigerator, a showcase with a separate refrigerator, a heat pump type hot water supply device, and the like.

Hereinafter, the present invention will be specifically described with reference to examples, but the technical scope of the present invention is not limited thereto.

<Examples 1 to 4>
An accelerated deterioration test by heating was conducted to evaluate the tendency of the amount of trifluoromethane (CHF ₃ ) produced in the combination of the mixed refrigerant containing trifluoroiodomethane (CF ₃ I) and various refrigerating machine oils.

As the refrigerant, the weight ratio of difluoromethane (HFC32), pentafluoroethane (HFC125), and trifluoroiodomethane (CF ₃ I) is HFC 32: HFC 125: CF ₃ I = 50 assuming a multi-air conditioner for buildings. A mixed refrigerant having a ratio of 10:40 was used.

As the refrigerating machine oil, a polyol ester oil represented by the following (symbol POE) or a polyvinyl ether oil represented by the following (symbol PVE) was used. Each refrigerating machine oil contained 0.3% by weight of DBPC, which is an antioxidant. Further, a total of 0.5% by weight of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, which is an alicyclic epoxy compound, and an alkylglycidyl ester compound, which is an aliphatic epoxy compound, were blended. Further, 1.0% by weight of tricresyl phosphate (TCP) was added to only the polyvinyl ether oil.

(Symbol POE) Hindered type polyol ester oil (pentaerythritol-based mixed fatty acid ester oil of 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid, kinematic viscosity at 40 ° C. = 64.9 mm ² / s)
(Symbol PVE) Polyvinyl ether oil (polymer of alkoxyvinyl, copolymer ether oil in which the alkoxy group is ethyloxy group and isobutyloxy group, kinematic viscosity at 40 ° C. = 66.8 mm ² / s)

(Accelerated deterioration test)
The accelerated deterioration test was carried out according to the following procedure. First, a polytetrafluoroethylene (PTFE) container was placed in a washed pressure vessel (pressure resistance: maximum 20 MPa, internal volume: 220 mL). Then, 60 g of refrigerating machine oil and a metal catalyst were placed in this PTFE container. The water content in the refrigerating machine oil (water content in the oil) was adjusted to less than 100 ppm by weight or 500 ppm by weight.

The water content in the oil was measured by the Karl Fischer titration method according to JIS K 2275-3. As the metal catalyst, aluminum, copper and iron (diameter: 2.0 mm, length: 300 mm) were sanded, washed with acetone and ethanol, and then wound into a coil.

Subsequently, the pressure vessel containing the refrigerating machine oil and the metal catalyst was depressurized to 100 Pa or less and evacuated, and then 12 g of the refrigerant was introduced and sealed. Then, this pressure vessel was placed in a constant temperature bath and heated at 150 ° C. for 504 hours. After heating, the pressure vessel was opened, and the total acid value of the refrigerating machine oil and the amount of iodine in the refrigerating machine oil (the amount of iodine in the oil) were measured. The amount of iodine in the oil represents the amount of the iodine component in the refrigerating machine oil derived from the decomposition of trifluoroiodomethane (CF ₃ I), and is an index of the decomposition of the refrigerant itself and the deterioration of the refrigerating machine oil and the like.

The total acid value was measured according to JIS K 2501: 2003 "Petroleum products and lubricating oil-neutralization value test method". The amount of iodine in oil was measured by combustion ion chromatography. The test oil was burned at 1000 ° C. to collect the iodine component with a hydrogen peroxide solution, and then this sample solution was injected into an ion chromatograph, and the eluate was sent and measured with an electric conductivity detector. As the eluent, a Na ₂ CO ₃ / NaHCO ₃ mixed solution was used. The flow rate of the eluent was 1.5 mL / min.

Before and after the accelerated deterioration test, the gas in the PTFE container was collected from the gas side valve of the constant temperature bath into a sampling bag (tedler bag), and the residual amount of the acid trapping agent and the gas composition were gas chromatographed. Quantitative analysis was performed using imaging.

Table 1 below shows the types of refrigerating machine oil, the amount of water in the refrigerating machine oil (water content in the oil), the total acid value of the refrigerating machine oil, the amount of iodine in the refrigerating machine oil (the amount of iodine in the oil), and the residual amount of the acid trapping agent. , The analysis result of the gas composition of the sample is shown.

As shown in Table 1, in Examples 1 and 2, the refrigerating machine oil is a polyol ester oil, but the total acid value of the refrigerating machine oil increases less than the initial value (0.01 mgKOH / g or less), and the refrigerating machine oil Deterioration was sufficiently suppressed. The amount of iodine in the oil became less than the detection sensitivity, and the decomposition of trifluoroiodomethane (CF ₃ I) was suppressed. The residual amount of the acid scavenger was relatively high, and it was confirmed that the deterioration factor was suppressed. As a result of analyzing the gas composition of the sample, it was confirmed that the amount of trifluoromethane (CHF ₃ ) was very small.

On the other hand, in Examples 3 and 4, the refrigerating machine oil was polyvinyl ether oil, but the total acid value of the refrigerating machine oil increased, and the refrigerating machine oil tended to deteriorate to some extent. The amount of iodine in the oil was relatively high, suggesting that the iodine component was incorporated into the oil with the decomposition of trifluoroiodomethane (CF ₃ I). The residual amount of the acid scavenger became 0, and it was confirmed that the acid scavenger was almost completely consumed. As a result of analyzing the gas composition of the sample, trifluoromethane (CHF ₃ ) was produced to some extent, suggesting the progress of decomposition of trifluoroiodomethane.

According to the results in Table 1, it was confirmed that when a mixed refrigerant containing trifluoroiodomethane (CF ₃ I) was heated in the coexistence with refrigerating machine oil, the production of trifluoro methane (CHF ₃ ) proceeded. As the refrigerating machine oil used in combination with the mixed refrigerant containing trifluoroiodomethane (CF ₃ I), polyol ester oil (POE) is preferable to polyvinyl ether oil (PVE).

<Examples 5 to 11>
In order to evaluate the performance of the adsorbent on trifluoromethane (CHF ₃ ) in the presence of the mixed refrigerant, an adsorption test was conducted for each type of adsorbent.

As the refrigerant, a mixed refrigerant assuming a multi air conditioner for buildings similar to the above-mentioned accelerated deterioration test was used. To this mixed refrigerant, trifluoromethane (CHF ₃ ) was added so as to be 3000 ppm.

As the adsorbent, activated alumina, activated carbon, and molecular sieve having different particle sizes, pore volumes, and specific surface areas were used. As the activated alumina, activated alumina "D-201" (manufactured by Union Showa Co., Ltd., meshes 7 to 12, particle size 1.6 to 3.0 mm), which is an adsorbent for dehydration and impurity removal, was classified and used. As the activated carbon, granular activated carbon "4GG for vapor phase" (manufactured by AS ONE Corporation, pellets 4 mm) was used. As the molecular sieve, Molecular Sives XH-10 (pore diameter 0.8 nm) was used.

(Adsorption test)
The adsorption test was carried out according to the following procedure. First, the PTFE container was placed in a washed pressure vessel (pressure resistance: maximum 20 MPa, internal volume: 220 mL). Then, 5 g of the adsorbent was put in this PTFE container. Subsequently, the pressure vessel containing the adsorbent was depressurized to 100 Pa or less and evacuated, and then 8 g of the refrigerant was introduced and sealed. Then, this pressure vessel was placed in a constant temperature bath and left at 20 ° C. for 168 hours.

Then, the gas in the PTFE container was collected from the gas side valve of the constant temperature bath into a sampling bag (Tedlar bag), and the concentration of trifluoromethane (CHF ₃ ) was quantitatively analyzed using gas chromatography. During the adsorption test, each adsorbent was handled in a glove box adjusted to an inert gas atmosphere.

Table 2 below shows the analysis results of the type of adsorbent, center particle size, pore volume, specific surface area, and concentration of trifluoromethane (CHF ₃ ) after the adsorption test.

As shown in Table 2, in each of Examples 5 to 11, the concentration of trifluoromethane (CHF ₃ ) after the adsorption test was lower than the initial value (3000 ppm). In Examples 8 and 9 using activated alumina having a large specific surface area, the concentration of trifluoromethane (CHF ₃ ) after the adsorption test was particularly low, and it was confirmed that the adsorption effect was high.

<Example 12>
A 3000-hour durability test was carried out on a refrigeration cycle device in which an adsorbent was placed on an accumulator and a refrigeration cycle device in which no adsorbent was placed under high-speed and high-load conditions.

As the refrigeration cycle device, a device equipped with a scroll-type sealed electric compressor and having a cooling capacity of 28 kW was used for a multi air conditioner for buildings. The rotation speed of the compressor was set to 6000 min ^-1 . A heat-resistant PET film (class B, temperature index: 130 ° C.) having a thickness of 250 μm was used to insulate the iron core of the motor from the coil. For the coil, a double-coated copper wire coated with a double coat of polyesterimide-amideimide was used.

As the refrigerant, a mixed refrigerant assuming a multi air conditioner for buildings similar to the above-mentioned accelerated deterioration test was used. 8000 g of the refrigerant was sealed in the refrigeration cycle. As the refrigerating machine oil, a polyol ester oil represented by (symbol POE) similar to the above-mentioned accelerated deterioration test was used. As shown in FIG. 3, the adsorbent was placed in the gas phase portion in the container of the accumulator. Activated alumina was used as the adsorbent.

As a dryer, a container filled with Molecular Sieves XH-10 (pore diameter 0.8 nm) was installed on the refrigeration cycle. For the refrigeration cycle device in which the adsorbent was placed in the accumulator, 1500 mL of refrigerating machine oil dehydrated so that the water content in the oil was 200 ppm by weight or less was sealed in the compressor. On the other hand, for the refrigeration cycle apparatus in which the adsorbent was not arranged, 1500 mL of refrigerating machine oil adjusted so that the water content in the oil was 600 ppm by weight was sealed in the compressor.

The refrigeration cycle device in which the adsorbent was placed in the accumulator and the refrigeration cycle device in which the adsorbent was not placed were operated for 3000 hours, respectively. Then, the gas in each accumulator was collected in a sampling bag (Tedlar bag) from the gas recovery port at the top of the accumulator, and the concentration of trifluoromethane (CHF ₃ ) was quantitatively analyzed using gas chromatography.

As a result, in the refrigeration cycle apparatus in which the adsorbent was not arranged, the concentration of trifluoromethane (CHF ₃ ) in the gas collected from the accumulator was about 4500 ppm. On the other hand, in the refrigeration cycle apparatus in which the adsorbent was arranged in the accumulator, the amount was reduced to 500 ppm or less.

Based on the above results, regarding a refrigeration cycle device using a mixed refrigerant containing trifluoroiodomethane (CF ₃ I), when an adsorbent that adsorbs trifluoromethane (CHF ₃ ) is installed in the gas phase part in the refrigeration cycle, trifluo It was confirmed that the concentration of lomethane can be suppressed for a long period of time.

1 Outdoor unit 2 Indoor unit 3 Compressor 4 Four-way valve 5 Outdoor heat exchanger (condenser / evaporator)
6 Receiver tank 7 Dryer (dryer)
8 Outdoor expansion valve (decompressor)
9 Accumulator 10 Outdoor blower 11 Indoor heat exchanger (evaporator / condenser)
12 Indoor expansion valve (decompressor)
13 Indoor blower 20 Fixed scroll member 20a Fixed lap 21 Swivel scroll member 21a Swivel lap 22 Frame 23 Crank shaft 24 Motor 25 Sealed container 26 Compression chamber 27 Discharge port 28 Discharge pipe 29 Oil hole 30 Main bearing 31 Sub bearing 32 Oil reservoir 40 Container 41 Inflow pipe 41a Inflow pipe 42 Outflow pipe 43 Mixing liquid 44 Oil return hole 45 Partition member 46 Adsorbent 50 Container 51 Inflow pipe 52 Outflow pipe 53 Mixing liquid 54 Partition member 55 Adsorbent

Claims (8)

A compressor that compresses the refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a decompressor that decompresses the refrigerant condensed by the condenser, and evaporation that evaporates the refrigerant decompressed by the decompressor. A refrigerating cycle apparatus including a container, an accumulator that separates droplets from a refrigerant containing droplets evaporated by the evaporator and temporarily stores them, and a dryer that removes water in the refrigerant.
The refrigerant is a mixed refrigerant containing trifluoroiodomethane, and has a vapor pressure of 1.1 MPa or more and 1.8 MPa or less at 25 ° C.
The compressor is a closed electric compressor in which a compression mechanism portion and a motor for driving the compression mechanism portion are provided in a closed container, and refrigerating machine oil for lubricating the sliding portion is filled. ,
A refrigeration cycle apparatus including an adsorbent that adsorbs trifluoromethane in the accumulator. In the refrigeration cycle apparatus according to claim 1,
A refrigeration cycle device in which the adsorbent is arranged above an inflow port for flowing the refrigerant into the accumulator. A compressor that compresses the refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a decompressor that decompresses the refrigerant condensed by the condenser, and evaporation that evaporates the refrigerant decompressed by the decompressor. It is provided with a container, an accumulator that separates droplets from the refrigerant containing the droplets evaporated by the evaporator and temporarily stores them, a dryer that removes water in the refrigerant, and a receiver tank that adjusts excess refrigerant. Refrigerant cycle device
The refrigerant is a mixed refrigerant containing trifluoroiodomethane, and has a vapor pressure of 1.1 MPa or more and 1.8 MPa or less at 25 ° C.
The compressor is a closed electric compressor in which a compression mechanism portion and a motor for driving the compression mechanism portion are provided in a closed container, and refrigerating machine oil for lubricating the sliding portion is filled. ,
A refrigeration cycle apparatus including an adsorbent that adsorbs trifluoromethane in the receiver tank. In the refrigeration cycle apparatus according to claim 3,
The adsorbent is, the refrigeration cycle device arranged on the upper portion of the receiver tank. In the refrigeration cycle apparatus according to any one of claims 1 to 4.
The refrigerating machine oil is a refrigerating cycle device which is a polyol ester oil. In the refrigeration cycle apparatus according to any one of claims 1 to 4.
A refrigeration cycle device in which the adsorbent is aluminum oxide. In the refrigeration cycle apparatus according to claim 6,
A refrigeration cycle device in which the aluminum oxide is γ-alumina. In the refrigeration cycle apparatus according to claim 7.
A refrigeration cycle device having a specific surface area of γ-alumina exceeding 100 m ² / g.

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