CN113531931A

CN113531931A - Refrigeration cycle device

Info

Publication number: CN113531931A
Application number: CN202110151484.XA
Authority: CN
Inventors: 太田亮; 赤田广幸; 内藤宏治; 多田修平; 吉田康孝
Original assignee: Hitachi Johnson Controls Air Conditioning Inc
Current assignee: Hitachi Johnson Controls Air Conditioning Inc
Priority date: 2020-04-22
Filing date: 2021-02-03
Publication date: 2021-10-22
Anticipated expiration: 2041-02-03
Also published as: JP6821075B1; JP2021173454A; CN113531931B

Abstract

The invention provides a refrigeration cycle device which uses an incombustible mixed refrigerant containing trifluoroiodomethane and having a low GWP, continuously suppresses the environment adaptability of the refrigerant which is increased along with the deterioration of the GWP, and has high reliability. The refrigeration cycle device is provided with: 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; an evaporator for evaporating the refrigerant decompressed by the decompressor; an accumulator for separating and temporarily accumulating the liquid droplets from the refrigerant containing the liquid droplets evaporated by the evaporator; and a dryer for removing moisture in the refrigerant, wherein the refrigerant is a mixed refrigerant containing trifluoroiodomethane, and has a vapor pressure at 25 ℃ of 1.1MPa or more and 1.8MPa or less, the compressor is a hermetic electric compressor, and the compressor is provided with a compression mechanism part and a motor for driving the compression mechanism part in a sealed container, and is filled with a refrigerating machine oil for lubricating a sliding part, and the accumulator is provided with an adsorbent for adsorbing trifluoromethane.

Description

Refrigeration cycle device

Technical Field

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

Background

Nowadays, various countermeasures against climate change are internationally taken in order to prevent global warming. In the 21 st conference of climate change framework treaty in 2015 (COP21), paris agreement was adopted to determine a long-term target to be achieved in the future. The objective of paris agreements is to pursue efforts to keep the rise in the world's average air temperature at a level well below 2 c and to suppress it to 1.5 c as compared to before the industrial revolution.

In japan, the preparation of a method for preventing global warming is being advanced mainly in the field associated with fluorine compounds. In regard to the use and management of a fluorine-based refrigerant used in a refrigerating and air-conditioning apparatus, a restriction target apparatus and a restriction target substance are stipulated in "law (freon discharge inhibition law) relating to rationalization of the use of freon and optimization of management".

Examples of the substances to be regulated include ozone layer-damaging substances (mainly, fluorine compounds bonded to chlorine or bromine) prescribed in "law on protection of the ozone layer by regulation of specific substances and the like" and greenhouse gas substances (mainly, substances having a high GWP composed of hydrogen, fluorine, and carbon) disclosed in "law on advancement of global warming countermeasures".

Currently, a target value of GWP, which is an index indicating the degree of environmental influence, is set by a weighted average for each specified product, with correction by the freon elimination suppression method. The objective of the household air conditioner was 750 to 2018, the objective of the store and office air conditioner was 750 to 2020, and the objective of the condenser unit and the stationary refrigerating and freezing unit (hereinafter, simply referred to as a refrigerator or the like) was 1500 to 2025.

Currently, as refrigerants for refrigerating and air-conditioning apparatuses, R410A [ HFC (hydro fluoro carbon) 32/HFC125(50/50 wt%) ], and R404A [ HFC125/HFC143a/HFC134a (44/52/4 wt%) ]areused. However, since the GWP of R410A is 1924 and that of R404A is 3943, replacement of alternative refrigerants having lower GWP has been advanced in recent years. The GWP of a refrigerant is inversely related to combustibility, and when the GWP of a refrigerant is made low, combustibility tends to be high.

As alternative refrigerants, difluoromethane (HFC32) (GWP of 677), 2,3,3, 3-tetrafluoropropene (HFO (hydrofluorolefin)1234yf) (GWP of 0), 1,3,3, 3-tetrafluoropropene (HFO1234ze) (GWP of 1), trifluoroethylene (HFO1123) (GWP of < 1), 3,3, 3-trifluoropropene (HFO1243zf) (GWP of 0) are known for reasons of thermophysical properties, low GWP, low toxicity, low combustibility, and the like.

Further, hydrofluorocarbons having a low GWP such as a mixed refrigerant of HFO and HFC32, HFC125, HFC134a, or the like, a hydrocarbon such as propane or propylene, or a monofluoroethane (HFC161) or a difluoroethane (HFC152a) are known. Further, low boiling compounds which are made nonflammable by halogenation with iodine, bromine, chlorine, or the like are also known.

With respect to the home air conditioner, there are other statutory modifications, most of which are converted to HFC32 which is slightly flammable. In a modification of the freezing safety regulations of the high pressure gas safety law (2016 month 11), HFC32, HFO1234yf, HFO1234ze were classified as "inert gases". However, since the refrigerant has low combustibility, it is also named "specific inert gas". For devices having a cooling capacity of 5 tons or more, a ventilation device and a device structure for preventing the leaked refrigerant from staying are required, and a detection alarm device needs to be installed at a place where the leaked refrigerant easily stays.

From such a background, in a multi-type air conditioner for high-rise buildings (multi-room type air conditioner) or a refrigerator which requires a higher refrigerating capacity, R410A is used at present instead of promoting replacement of a low GWP refrigerant. In a multi-split air conditioner or a refrigerator for a high-rise building, since the refrigerant sealing amount is large and the risk of refrigerant leakage is high, it is difficult to use a low-ignition-quality refrigerant with a low GWP in the present situation.

On the other hand, as a refrigerant for refrigerators, in view of the relationship with the freon discharge inhibition method, a non-flammable mixed refrigerant having a GWP of 1500 or less and containing HFO1234yf and HFO1234ze has attracted attention. For example, development of a refrigerator using R448A (HFC32/HFC125/HFC134a/HFO1234ze/HFO1234yf), R449A (HFC32/HFC125/HFC134a/HFO1234yf) is being advanced. However, R448A and R449A cannot be made nonflammable unless the GWP is controlled to about 1100 to 1400, and therefore, when the GWP is lowered, the combustibility needs to be suppressed.

Nowadays, as an international countermeasure for preventing global warming, the restrictions of the montreal protocol are strengthened. The substances to be restricted at first are specific substances predetermined in "law on protection of the ozone layer by restricting specific substances and the like" in japan. However, in the 28 th montreal protocol of the ruggeda convention (MOP28) held by the bugada based ugali in 2016, the restriction on alternative freon and the like disclosed in "law relating to the progress of global warming" in japan has been expanded.

In the modification of Bulgarian, the production amount and consumption amount of the limiting substance were consistently set to-10% in 2019, to-40% in 2024, to-70% in 2029, to-80% in 2034, and to-85% in 2036 based on 2011 to 2013. On the other hand, it was predicted that the target value could be achieved by the current freon discharge inhibition method by 2024. However, after 2029, it was estimated that it was difficult to reach the target value.

Under such a condition, trifluoroiodomethane (CF) is contained₃I) Mixed refrigerants that are low GWP and non-flammable are of interest. According to the mixed refrigerant containing trifluoroiodomethane, the refrigerant combustibility can be suppressed, and the refrigerating capacity can be obtained close to that of R410A used in the conventional multi-type air conditioner for high-rise buildings and the like, and it is expected that the refrigerant can be used without a significant change in designA refrigerating and air-conditioning apparatus having high environmental compatibility can be realized.

Patent document 1 describes a technique for purifying an etchant or monofluoromethane used as a cleaning agent in a thin film production process. In this technique, trifluoromethane (CHF) is separated from monofluoromethane by chemical absorption₃). The chemical absorption uses a treatment liquid containing an amide and a base.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012-121855

Disclosure of Invention

Problems to be solved by the invention

When trifluoroiodomethane (CF) is mixed with a refrigerant such as difluoromethane (HFC32)₃I) The GWP can be kept low and the combustibility can be suppressed. Therefore, a refrigerant having low GWP and low combustibility can be obtained. However, trifluoroiodomethane is chemically decomposed in the presence of moisture, oxygen, heat, or the like to produce trifluoromethane (CHF), which is one of hydrofluorocarbons₃) Hydrogen fluoride, hydrogen iodide, and the like.

Refrigeration cycle apparatuses such as refrigeration and air-conditioning apparatuses include various metal materials, as typified by a joint portion formed of a copper pipe, a flared nut made of brass, or silver solder, in a refrigeration cycle in which a refrigerant flows. The metal material may catalyze the decomposition of trifluoroiodomethane and the downstream reaction accompanying the decomposition. In addition, a refrigerant circulating in the refrigeration cycle contains a refrigerating machine oil, which is an organic molecule to which hydrogen atoms are bonded by applying sliding heat or the like to the compressor. Therefore, when the operation of the refrigeration cycle apparatus is continued, the deterioration of the refrigerant and the increase in the concentration of the deterioration reaction product may progress in the presence of a catalyst or heat.

Among the degradation reaction products generated by the decomposition of trifluoroiodomethane, trifluoromethane has a GWP of 12400 and is a substance having a high greenhouse effect. If the concentration of trifluoromethane is increased, the GWP of the refrigerant becomes large. Further, there is a possibility that the refrigerating capacity and the like are adversely affected. Therefore, a technique for suppressing the increase in the concentration of trifluoromethane in the refrigeration cycle is desired.

Patent document 1 describes a technique of reacting trifluoromethane (CHF)₃) Chemical absorption by a treatment liquid containing an amide and an alkali. When such a technique is used in a refrigeration cycle, trifluoroiodomethane itself is also deteriorated. When the mixed refrigerant containing trifluoroiodomethane is subjected to heat of sliding of the compressor or the like in the presence of the amide, the concentration of trifluoromethane may conversely increase. In addition, not only the refrigerant but also the refrigerating machine oil deteriorates, and the reliability of the refrigeration cycle apparatus is significantly reduced.

Therefore, an object of the present invention is to provide a refrigeration cycle apparatus having high environmental suitability and high reliability, which uses an incombustible mixed refrigerant having a low GWP and containing trifluoroiodomethane, and can continuously suppress the increase in GWP associated with the deterioration of the refrigerant.

Means for solving the problems

In order to solve the above problem, a refrigeration air-conditioning cycle device according to the present invention includes: a compressor that compresses a refrigerant; a condenser for condensing the refrigerant compressed by the compressor; a decompressor for decompressing the refrigerant condensed by the condenser; an evaporator that evaporates the refrigerant decompressed by the decompressor; an accumulator that separates and temporarily accumulates liquid droplets from the refrigerant containing the liquid droplets evaporated by the evaporator; and a dryer that removes moisture in the refrigerant, wherein the refrigerant is a mixed refrigerant containing trifluoroiodomethane, the vapor pressure at 25 ℃ is 1.1MPa or more and 1.8MPa or less, the compressor is a sealed electric compressor, the compressor is provided with a compression mechanism and a motor that drives the compression mechanism in a sealed container, the compressor is filled with a refrigerator oil that lubricates a sliding portion, and the accumulator is provided with an adsorbent that adsorbs trifluoromethane.

The effects of the invention are as follows.

According to the present invention, it is possible to provide a refrigeration cycle apparatus which uses an incombustible mixed refrigerant containing trifluoroiodomethane and having a low GWP, and which can continuously suppress the increase in GWP associated with the deterioration of the refrigerant, and which has high environmental suitability and high reliability.

Drawings

Fig. 1 is a configuration diagram of a refrigeration cycle showing an example of a multi-type air conditioner for a building as a refrigeration cycle apparatus.

Fig. 2 is a longitudinal sectional view showing an example of the hermetic electric compressor.

Fig. 3 is a longitudinal sectional view showing an example of the accumulator.

Fig. 4 is a longitudinal sectional view showing an example of the tank.

In the figure:

1-outdoor unit, 2-indoor unit, 3-compressor, 4-four-way valve, 5-outdoor heat exchanger (condenser/evaporator), 6-storage 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 part, 20 a-fixed wrap, 21-orbiting scroll part, 21 a-orbiting wrap, 22-frame, 23-crankshaft, 24-motor, 25-sealed container, 26-compression chamber, 27-ejection port, 28-ejection pipe, 29-oil hole, 30-main bearing, 31-auxiliary bearing, 32-oil accumulation portion, 40-container, 41-inflow pipe, 41 a-inflow port, 42-pipe, 43-mixed liquid, 44-oil return hole, 45-separation member, 46-adsorbent, 50-container, 51-inflow tube, 52-outflow tube, 53-mixed liquid, 54-separation member, 55-adsorbent.

Detailed Description

Hereinafter, a refrigeration cycle apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following drawings, the same reference numerals are used for the common components, and redundant description is omitted.

< refrigeration cycle apparatus >

The refrigeration cycle apparatus of the present embodiment is an apparatus having a capacity of cooling a cooling target by a thermodynamic refrigeration cycle using a refrigerant. When the refrigeration cycle apparatus has a cooling capability, the apparatus may have a capability of performing a reverse thermal cycle to the refrigeration cycle. The refrigeration cycle apparatus can be applied to various refrigeration and air-conditioning apparatuses such as an air conditioner and a refrigerator.

The refrigeration cycle apparatus of the present embodiment includes: a compressor that compresses a refrigerant; a condenser that condenses the refrigerant compressed by the compressor; a decompressor for decompressing the refrigerant condensed by the condenser; and an evaporator that evaporates the refrigerant decompressed by the decompressor. As the compressor, a hermetic electric compressor is used which includes a compression mechanism section and a motor for driving the compression mechanism section in a hermetic container, and is filled with a refrigerating machine oil for lubricating a sliding section.

The refrigeration cycle apparatus of the present embodiment includes, in addition to the compressor, the condenser, the decompressor, and the evaporator, an accumulator that separates and temporarily accumulates liquid droplets from the refrigerant containing the liquid droplets evaporated by the evaporator, and a dryer that removes moisture in the refrigerant. The refrigeration cycle apparatus may include an accumulator for adjusting an excess refrigerant in addition to the accumulator and the dryer.

In the refrigeration cycle apparatus of the present embodiment, trifluoroiodomethane (CF) is used as the refrigerant₃I) The mixed refrigerant of (1). The accumulator and the accumulator are parts in which the flow rate of the refrigerant is low in the refrigeration cycle in which the refrigerant flows, and correspond to trifluoromethane (CHF) generated by decomposition of trifluoroiodomethane₃) A part where retention is easy.

In the refrigeration cycle apparatus of the present embodiment, an adsorbent that adsorbs trifluoromethane is provided at such a location. By providing an adsorbent that adsorbs trifluoromethane, an increase in the concentration of trifluoromethane in the refrigeration cycle is suppressed, and an increase in GWP associated with deterioration of the refrigerant is continuously suppressed, thereby ensuring environmental compatibility and reliability of the refrigeration cycle apparatus.

Here, a specific example will be described of the refrigeration cycle apparatus and the compressor used in the refrigeration cycle apparatus according to the present embodiment.

The refrigeration cycle apparatus according to the present embodiment can be applied to an air conditioner such as a multi-split air conditioner for a high building (multi-room type air conditioner) shown in fig. 1.

As shown in fig. 1, a multi-type air conditioner 100 for a high-rise building includes an outdoor unit 1 and

indoor units

2a and 2 b. In fig. 1, the multi-split air conditioner 100 for a high building includes two

indoor units

2a and 2 b. However, the multi-split air conditioner 100 for a high building may include any 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 storage tank 6, a dryer (dryer) 7, an outdoor expansion valve (decompressor) 8, an accumulator 9, and an outdoor fan 10.

The four-way valve 4, the accumulator 9, and the compressor 3 are connected in a closed loop via refrigerant pipes. The

indoor units

2a and 2b are connected to the other connection portion of the four-way valve 4 via a refrigerant pipe. The outdoor heat exchanger 5, the accumulator 6, the dryer 7, the outdoor expansion valve 8, and the

indoor units

2a and 2b are connected to the remaining connection portion of the four-way valve 4 via refrigerant pipes in this order.

The refrigerant pipes connecting the above-described devices and the devices form a refrigeration cycle as a circulation path for circulating a refrigerant between the outdoor unit 1 and the

indoor units

2a and 2 b. A predetermined refrigerant described below is enclosed in the refrigeration cycle. For the purposes of lubrication, sealing of the refrigerant, cooling, and the like, a predetermined refrigerating machine oil described below is sealed in the compressor 3.

The compressor 3 is a hermetic electric compressor, and a compression mechanism and a motor for driving the compression mechanism are incorporated in a hermetic 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 outside air, and functions as a condenser during the cooling operation and as an evaporator during the heating operation.

The accumulator 6 is a container for adjusting the remaining refrigerant. The gas refrigerant separated from the liquid refrigerant is temporarily accumulated in the accumulator 6. Substantially only liquid refrigerant is sent from the accumulator 6 to the outdoor expansion valve 8. Note that although the receiver 6 is provided in the refrigeration cycle shown in fig. 1, the receiver 6 may not be provided. There is a specification in which the accumulator 6 is not provided depending on the type of the refrigeration cycle apparatus.

The dryer 7 is a device for removing moisture in the refrigerant. The dryer 7 shown in fig. 1 is a filter of a tandem type. In order to remove moisture that causes deterioration of the refrigerant and the refrigerator oil, a drying agent is filled in the dryer 7.

As the drying agent, synthetic zeolite having a pore diameter for adsorbing water, zeolite such as molecular sieve, silica gel, activated alumina, or the like can be used. The drying agent is preferably a drying agent having pores with a size not larger than the effective diameter of water and larger than the effective diameter of the refrigerant component, the refrigerating machine oil, the additive, the trifluoromethane, or the like. That is, it is preferable that the desiccant selectively adsorbs water and hardly adsorbs refrigerant components larger than water, refrigerator oil, additives, trifluoromethane, and the like.

In fig. 1, the dryer 7 is provided in a bypass path in the refrigeration cycle. The bypass is provided between the accumulator 6 and the outdoor expansion valve 8 in parallel with the main flow pipe. By providing the above section, the high-temperature refrigerant is prevented from contacting the desiccant. By providing the bypass, pressure loss due to the dryer 7 and abrasion and pulverization of the drying agent due to the high-flow-rate refrigerant are suppressed. However, the dryer 7 may be provided in a main flow pipe or the like between the accumulator 6 and the outdoor expansion valve 8. If the dryer 7 is provided in the main flow pipe, the number of components 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 pressure reducer during the cooling operation. The accumulator 9 is a device for performing gas-liquid separation of the gas refrigerant and the liquid refrigerant, and separates and temporarily accumulates liquid droplets from the refrigerant including the liquid droplets. The outdoor air-sending device 10 is provided to send 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 include indoor heat exchangers (evaporators and condensers) 11a and 11b, indoor expansion valves (pressure reducers) 12a and 12b, and

indoor fans

13a and 13b, respectively. When the multi-type air conditioner 100 for a high-rise building includes two or more indoor units (2a, 2b, … …), the indoor units have the same configuration and can be connected by refrigerant pipes so as to form a parallel refrigeration cycle.

The

indoor heat exchangers

11a and 11b exchange heat between the refrigerant and indoor air, and function as evaporators during the cooling operation and as condensers during the heating operation. The

indoor expansion valves

12a and 12b are configured by, for example, electronic expansion valves, temperature expansion valves, or the like, and function as pressure reducers during heating operation. The indoor air-sending

devices

13a and 13b are provided to send indoor air to the

indoor heat exchangers

11a and 11b, and promote heat exchange between the refrigerant and the indoor air.

The cooling of the multi-type air conditioner 100 for a high-rise building is performed according to the following principle. The high-temperature and high-pressure gas refrigerant adiabatically compressed by the compressor 3 is sent to the outdoor heat exchanger 5 through the four-way valve 4. Then, in the outdoor heat exchanger 5 functioning as a condenser, the gas refrigerant is cooled by heat exchange with the outside air, and becomes a high-pressure liquid refrigerant. The high pressure liquid refrigerant enters the accumulator 6 and separates the incompletely condensed gas refrigerant. Moisture contained in the liquid refrigerant is removed by the dryer 7. The high-pressure liquid refrigerant separated into the gas refrigerant is decompressed and expanded by the outdoor expansion valve 8, and becomes a gas-liquid two-phase refrigerant (a low-temperature low-pressure liquid refrigerant that slightly contains the gas refrigerant).

The gas-liquid two-phase refrigerant decompressed by the outdoor expansion valve 8 is sent to the

indoor heat exchangers

11a and 11 b. Then, the

indoor heat exchangers

11a and 11b functioning as evaporators exchange heat with indoor air to evaporate and absorb heat, thereby becoming low-temperature and low-pressure gas refrigerant. The low-temperature low-pressure gas refrigerant enters the energy accumulator 9 through the four-way valve 4, and the incompletely evaporated low-temperature low-pressure liquid refrigerant is separated. The low-temperature low-pressure gas refrigerant separated from the liquid refrigerant is returned to the compressor 3. Thereafter, the same cycle is repeated to continue cooling.

The heating of the multi-type air conditioner 100 for a high-rise building is performed by a reverse cycle to that in the cooling. The high-temperature and high-pressure gas refrigerant adiabatically compressed by the compressor 3 is sent to the

indoor heat exchangers

11a and 11b by switching the four-way valve 4. Then, the

indoor heat exchangers

11a and 11b functioning as condensers provide heat to the indoor air, and thereafter, the outdoor heat exchanger 5 functioning as an evaporator absorbs heat from the outside air. The same cycle as above is repeated to continue heating.

The refrigeration cycle apparatus of the present embodiment can include, for example, a scroll-type hermetic electric compressor shown in fig. 2 as a compressor for compressing a refrigerant. The sealed electric compressor can be used as the compressor 3 of the multi-split air conditioner 100 for a high building shown in fig. 1.

As shown in fig. 2, the hermetic electric compressor 3 includes: a fixed scroll member 20 having a spiral fixed wrap 20a provided perpendicularly to an end plate; an orbiting scroll member 21 having an orbiting wrap 21a in a spiral shape having substantially the same shape as the fixed wrap 20 a; a frame 22; a crankshaft 23 that causes the orbiting scroll member 21 to orbit; a motor 24 that drives the crankshaft 23; and a closed container 25 in which the above components are built.

The fixed scroll member 20 is fixed to the frame 22 by bolts. The cross ring that regulates the rotation of the orbiting scroll member 21 is slidably engaged with the orbiting scroll member 21. The orbiting scroll member 21 is supported by an orbiting bearing. An eccentric pin for eccentrically driving the orbiting scroll member 21 is fitted into the orbiting bearing.

The fixed scroll member 20 and the orbiting scroll member 21 are disposed to face each other so that the fixed wrap 20a and the orbiting wrap 21a mesh with each other, and form a compression mechanism portion that compresses a refrigerant. A compression chamber 26 is formed between the fixed wrap 20a and the revolving wrap 21 a.

The main shaft portion of the crankshaft 23 is rotatably supported by a main bearing 30 as a rolling bearing. The sub shaft portion is rotatably supported by a sub bearing 31 as a rolling bearing. A balance weight is attached to an intermediate portion of the crankshaft 23.

The crankshaft 23 is driven and rotated at a constant rotation speed or a rotation speed corresponding to a voltage generated by inverter control by a motor 24. When the crankshaft 23 is rotated by the operation of the motor 24, the orbiting scroll member 21 orbits eccentrically with respect to the fixed scroll member 20.

In the hermetic electric compressor 3, an intake pipe for taking in refrigerant from a refrigeration cycle as a refrigerant circulation passage is provided in an upper portion of the sealed container 25. The suction pipe communicates with a suction port provided on the outer side of the fixed scroll 20 for the compression chamber 26. When the orbiting scroll member 21 performs an orbiting motion, the compression chamber 26 located at the outermost side moves toward the center of the compression mechanism portion while gradually reducing the volume. 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, it communicates with a discharge port 27 provided through the fixed scroll member 20. The closed casing 25 has an upper space and a lower space with the fixed scroll 20 interposed therebetween. The gas refrigerant compressed in the compression chamber 26 is discharged from the discharge port 27 to the upper space in the closed casing 25. The gas refrigerant released into the upper space moves to the lower space through a plurality of discharge gas passages penetrating the fixed scroll member 20. Then, the refrigerant is discharged from a discharge pipe 28 penetrating the sealed container 25 provided in the lower space to the refrigeration cycle as a circulation path of the refrigerant.

An oil reservoir 32 for storing the refrigerating machine oil is provided below the motor 24 in the closed casing 25. During the operation of the compression mechanism, the refrigerating machine oil in the oil accumulation portion 32 is sucked by the pressure difference. Then, the lubricant is supplied to a sliding portion between the orbiting scroll part 21 and the crankshaft 23, a rolling bearing of a main bearing 30 supporting a main shaft portion of the crankshaft 23, a rolling bearing of a sub bearing 31 supporting a sub shaft portion of the crankshaft 23, and the like through a lubricant hole 29 provided in the crankshaft 23.

In fig. 2, the hermetic electric compressor 3 is a scroll compressor, but as a compressor constituting the refrigeration cycle apparatus, for example, a screw compressor, a rotary compressor, a twin rotary compressor, a two-stage compression rotary compressor, a swing compressor in which a roller and a vane are integrated, or the like can be used in addition to the scroll compressor.

Fig. 3 is a longitudinal sectional view showing an example of the accumulator.

As shown in fig. 3, the accumulator 9 may include: a container 40 constituting a main body; an inflow pipe 41 for allowing the refrigerant to flow into the container 40; an outflow pipe 42 for allowing the gas refrigerant to flow out of the container 40; and a partition member 45 supported at an upper portion in the container 40 so as to be positioned above the liquid surface of the mixed liquid 43.

The accumulator 9 is a device for separating liquid droplets from the gaseous refrigerant flowing into the vessel 40 and temporarily accumulating the liquid droplets in the vessel 40. In fig. 3, the container 40 has a bottomed cylindrical shape. The upper part of the container 40 is closed 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.

In fig. 3, the inflow pipe 41 is an L-shaped pipe. 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 into the container 40 through the lid member, and is bent laterally at an upper portion in the container 40. The other end of the inflow pipe 41 opens laterally at an upper portion in the container 40. An inlet 41a for allowing the refrigerant to flow into the container 40 is formed as an opening at the other end of the inlet pipe 41.

In fig. 3, the outflow pipe 42 is a U-shaped pipe having different lengths on the left and right sides. One end of the outflow pipe 42 is opened upward at an upper portion in the container 40. The outflow pipe 42 extends from an upper portion in the container 40 to a lower portion in the container 40, is bent at the lower portion in the container 40, and extends from the lower portion in the container 40 to an upper portion 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.

During the operation of the refrigeration cycle, the mixed liquid 43 is temporarily stored in the container 40. The mixed liquid 43 is a liquid obtained by mixing a liquid refrigerant and refrigerator oil, and is derived from liquid droplets separated from a gas refrigerant. The middle portion of the outflow tube 42 is located at a lower portion within the container 40. An oil return hole 44 is provided in the middle of the outflow pipe 42 at a position immersed in the mixed liquid 43.

During 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 contains droplets of the liquid refrigerant that have not completely evaporated in the

indoor heat exchangers

11a and 11b, and droplets of the refrigerating machine oil. When such a gas refrigerant flows into the container 40, the liquid refrigerant and the refrigerator oil are separated from the gas refrigerant due to a difference in specific gravity. By separating the liquid refrigerant, sintering due to poor compression and insufficient lubrication in the compressor 3 is prevented.

When the liquid refrigerant and the refrigerating machine oil separated from the gas refrigerant flow into the container 40, they flow down to the bottom of the container 40 and are 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 being sucked into the compressor 3, a part of the mixed liquid 43 stored in the tank 40 is sucked through the oil return hole 44. The compressor 3 is lubricated by sucking the refrigerating machine oil through the oil return hole 44.

Fig. 3 shows an example in which an oil return hole 44 is provided in the outflow pipe 42. However, in addition to the oil return hole 44, another oil return hole for adjusting the dryness of the refrigerant, and a pressure equalizing hole for preventing flooding or the like at the time of starting the compressor 3 may be provided in the outflow pipe 42. The additional oil return hole can be provided, for example, in a straight pipe portion at a height at which the liquid phase portion located above the oil return hole 44 is located. The pressure equalizing hole can be provided in a straight pipe portion or the like at a height at which the gas phase portion in the upper portion of the outlet pipe 42 is located.

As shown in FIG. 3, trifluoromethane (CHF) was adsorbed₃) Can be disposed within the vessel 40 of the accumulator 9. The adsorbent 46 is preferably disposed in the gas phase portion of the accumulator 9, and more preferably above the inlet 41 a. The trifluoromethane is a gas at the operating temperature of the refrigerant. The temperature of the upper portion of the accumulator 9 is relatively low, and the refrigerant component and the refrigerating machine oil are small. Therefore, if such an arrangement is adopted, the liquid refrigerant can be effectively adsorbed, separated from the liquid refrigerant, and diffusedTrifluoromethane to the gas phase section.

In fig. 3, the adsorbent 46 is provided on the partition member 45. The partition member 45 is provided in a net shape so as to allow gas to pass therethrough, and is attached substantially horizontally so as to vertically partition the upper portion in the container 40. However, the partition member 45 may be provided in a porous form having one or more through holes, a porous form having a plurality of through holes, or the like, in order to secure air permeability and strength as a member. Examples of the porous partition member 45 include a metal lath, a metal mesh, and a punching metal.

Such a partition member 45 can be installed in the container 40 in order to provide 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 shaped to vertically partition the entire cross section of the container 40, or may be shaped to vertically partition a part of the cross section.

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

Fig. 4 is a longitudinal sectional view showing an example of the tank.

As shown in fig. 4, the tank 6 may include: a container 50 constituting a main body; an inflow pipe 51 for allowing the refrigerant to flow into the container 50; an outflow pipe 52 for allowing the gas refrigerant to flow out of the container 50; and a partition member 54 supported at an upper portion in the container 50 so as to be positioned above the liquid surface of the mixed liquid 53.

The accumulator 6 is a device for adjusting the surplus refrigerant, temporarily accumulates the liquid refrigerant flowing into the tank 50 in the tank 50, and restrictively supplies the liquid refrigerant separated into the gas refrigerant to the outdoor expansion valve 8. In fig. 4, the container 50 has a bottomed cylindrical shape. The upper part of the container 50 is closed 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.

In fig. 4, the inflow pipe 51 is an L-shaped pipe, and is attached to the upper portion of the container 50 in an inverted L-shape with its 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 a lower portion in the container 50 so as to penetrate the lid member. The other end of the inflow pipe 51 opens downward at a lower portion in the container 50.

In fig. 4, the outlet pipe 52 is an L-shaped pipe as in the inlet pipe 51, and is attached to the upper portion of the container 50 in an inverted L-shape with its opening facing downward, symmetrically to the inlet pipe 51. One end of the outflow pipe 52 opens downward at a lower portion in the container 40. The outflow pipe 52 extends from the lower portion inside the container 50 to the upper portion 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.

During operation of the refrigeration cycle, the liquid refrigerant 53 is temporarily stored in the container 50. The amount of the refrigerant supplied to the outdoor expansion valve 8 is adjusted by storing a part of the liquid refrigerant 53 as excess refrigerant. After separating the gas refrigerant that has not been completely condensed in the container 50, the liquid refrigerant 53 is supplied to the outdoor expansion valve 8.

As shown in FIG. 4, trifluoromethane (CHF) was adsorbed₃) The adsorbent 55 of (2) can be disposed in the container 50 of the storage tank 6. The adsorbent 55 is preferably disposed in the gas phase portion of the accumulator 6, and is preferably disposed above the highest liquid level of the surplus refrigerant stored in the accumulator 6. The trifluoromethane is a gas at the operating temperature of the refrigerant. The temperature of the upper portion of the accumulator 6 is relatively low, and the refrigerant component and the refrigerator oil are small. Therefore, with such an arrangement, the trifluoromethane separated from the liquid refrigerant and diffused into the gas phase portion can be effectively adsorbed.

In fig. 4, the adsorbent 55 is provided on the partition member 54. The partition member 54 is provided in a mesh shape so as to allow gas to pass therethrough, and is attached substantially horizontally so as to vertically partition the upper portion in the container 50. However, the partition member 54 may be provided in a porous form having one or more through holes, a porous form having a plurality of through holes, or the like, in order to secure air permeability and strength as a member, as in the case of the partition member 45.

Such a partition member 54 can be installed in the container 50 in order to provide 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. Like the partition member 45, the partition member 54 may be shaped to vertically partition the entire cross section of the container 50, or may be shaped to vertically partition a part of the cross section.

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

In the refrigeration cycle apparatus of the present embodiment, adsorption of trifluoromethane (CHF) may be provided only in the accumulator 9 shown in fig. 3₃) The adsorbent of (3) may be provided only in the accumulator 6 shown in fig. 4, or may be provided in both the accumulator 9 and the accumulator 6.

However, from the viewpoint of effective adsorption, the adsorbent that adsorbs trifluoromethane is preferably disposed at a lower temperature, and is preferably disposed at least in the accumulator 9. The shape of the accumulator 9 and the container of the accumulator 6, the shapes of the inflow pipe and the outflow pipe, the connection positions of the inflow pipe and the outflow pipe, and the like are not particularly limited.

The refrigerant and the refrigerating machine oil used in the refrigeration cycle apparatus according to the present embodiment will be described in detail below.

< refrigerant >

As a refrigerant of the refrigeration cycle apparatus, a refrigerant containing trifluoroiodomethane (CF) is used₃I) The mixed refrigerant of (1). The refrigerant preferably contains difluoromethane (HFC32), pentafluoroethane (HFC125) and trifluoroiodomethane (CF)₃I) The mixed refrigerant of (1). The mixed refrigerant may contain only the above three components as refrigerant components, or may contain other refrigerant components in addition to the above three components. The additive may be added to the mixed refrigerant or may not be added to the mixed refrigerant.

Among the refrigerant components, difluoromethane is mainly used for ensuring high freezing capacity and energy efficiency. Furthermore, pentafluoroethane is mainly used to narrow the temperature gradient. Further, trifluoroiodomethane is mainly used for reducing the GWP and combustibility of the mixed refrigerant itself. In the present specification, the temperature gradient refers to a temperature difference between a start temperature and an end temperature of a phase change (evaporation, condensation) of the refrigerant.

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

The Global Warming Potential (GWP) of the refrigerant in the refrigeration cycle apparatus is 750 or less, preferably 500 or less, and more preferably 150 or less. When the GWP is 750 or less, the refrigerant is excellent in environmental performance, and is highly suitable for regulatory restrictions, and thus can be used not only for refrigerators but also for air conditioners.

The GWP of the refrigerant can be adjusted to 750 or less by changing the composition ratio of the mixed refrigerant. GWP of difluoromethane (HFC32) 677, of pentafluoroethane (HFC125) 3500, and of trifluoroiodomethane (CF 125)₃I) GWP of (1) is 0.4.

The saturated vapor pressure of the refrigerant in the refrigeration cycle apparatus at 25 ℃ is preferably 1.1MPa or more and 1.8MPa or less. When the saturated vapor pressure is within this range, the conventional general refrigeration cycle apparatus using R32, R410A, R404A, and the like can obtain the same refrigeration capacity, refrigerant sealing property, and the like without significantly changing the system, design, construction method of refrigerant piping, and the like.

By changing the composition ratio of the mixed refrigerant, the saturated vapor of the refrigerant can be evaporatedThe steam pressure is adjusted to 1.1MPa or more and 1.8MPa or less. For the saturated vapor pressure at 25 ℃, difluoromethane (HFC 32): about 1.69MPa, pentafluoroethane (HFC 125): about 1.38MPa, trifluoroiodomethane (CF)₃I) The method comprises the following steps About 0.5 MPa.

Difluoromethane (HFC32) in the refrigerant for the refrigeration cycle apparatus 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 or more and 50% by weight or less. Furthermore, pentafluoroethane (HFC125) is preferably 5 wt% or more and 25 wt% or less. Further, trifluoroiodomethane (CF)₃I) Preferably 30% by weight or more and 60% by weight or less.

With such a composition, a mixed refrigerant containing a slightly flammable difluoromethane can be subjected to pseudo-azeotropic distillation with pentafluoroethane, and the GWP can be reduced with trifluoroiodomethane, and the mixed refrigerant can be made nonflammable sufficiently with a small amount of pentafluoroethane and trifluoroiodomethane.

The refrigerant of the refrigeration cycle apparatus may contain CO as another refrigerant component in addition to the three components described above₂Hydrocarbons, ethers, fluoroethers, fluoroolefins, HFC, HFO, HClFO, HBrFO, and the like.

Further, "HFC" represents hydrofluorocarbons. "HFO" is a hydrofluoroolefin consisting of carbon atoms, fluorine atoms, and hydrogen atoms, having at least one carbon-carbon double bond. "HClFO" is composed of carbon, chlorine, fluorine and hydrogen atoms and has at least one carbon-carbon double bond. "HBrFO" is composed of carbon atoms, bromine atoms, fluorine atoms, and hydrogen atoms, and has at least one carbon-carbon double bond.

Examples of HFC include difluoromethane (HFC32), pentafluoroethane (HFC125), 1,11,2, 2-tetrafluoroethane (HFC134), 1,1,11, 2-tetrafluoroethane (HFC134a), trifluoroethane (HFC143a), difluoroethane (HFC152a), 1,1,1,2,3, 3-heptafluoropropane (HFC227ea), 1,1,1,3,3, 3-hexafluoropropane (HFC236fa), 1,1,1,3, 3-pentafluoropropane (HFC245fa), and 1,1,1,3, 3-pentafluorobutane (HFC365 mfc).

Examples of the fluoroolefin include vinyl fluoride, propylene fluoride, butene fluoride, chlorofluoroethylene and chlorofluoropropylExamples of alkenes, chlorofluorobutenes. Examples of the fluoropropenes include 3,3, 3-trifluoropropene (HFO1243zf), 1,3,3, 3-tetrafluoropropene (HFO1234ze), 2,3,3, 3-tetrafluoropropene (HFO1234yf), and HFO 1225. As fluorobutene, C can be shown₄H₄F₄(HFO1354)、C₄H₃F₅(HFO1345)、C₄H₂F₆(HFO 1336).

As the chlorofluoroethylene, C may be mentioned₂F₃Examples of Cl (CTFE). Examples of chlorofluoropropenes include 2-chloro-3, 3, 3-trifluoro-1-propene (HCFO1233xf) and 1-chloro-3, 3, 3-trifluoro-1-propene (HCFO1233 zd).

< refrigerating machine oil >

As the refrigerating machine oil of the refrigeration cycle apparatus, polyol ester oil (POE) and polyvinyl ether oil (PVE) can be used.

Polyol ester oils are obtained by the condensation reaction of a polyol with a monovalent fatty acid. Examples of the polyhydric alcohol include neopentyl glycol, trimethylolpropane, pentaerythritol, and dipentaerythritol. Examples of the monovalent fatty acid include n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, 2-methylbutyric acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, and 3,5, 5-trimethylhexanoic acid. One or more kinds of polyhydric alcohols and monovalent fatty acids may be used.

As the polyvinyl ether oil, polymers of an alkoxyvinyl group such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether can be used.

The refrigerating machine oil of the refrigeration cycle apparatus is preferably a polyol ester oil. If the polyvinyl ether oil is mixed with trifluoroiodomethane (CF)₃I) Is heated in the coexistence of (A) and (B), trifluoromethane (CHF) is easily produced₃). Since the vicinity of the sliding portion of the compressor and the periphery of the discharge port are at high temperatures, the need for an additive for preventing deterioration of trifluoroiodomethane is high when the polyvinyl ether oil is used.

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

The polyol ester oil is preferably 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. [ wherein, in the chemical formulas (1) and (2), R¹The alkyl groups having 4 to 9 carbon atoms may be the same or different.]

Chemical formula 1

Chemical formula 2

As R¹The alkyl group may be either a linear alkyl group or a branched alkyl group. As R¹Specific examples thereof include n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, 1-ethylpentyl, isohexyl, and 2-ethylhexyl.

In the pentaerythritol-based compound represented by the chemical formula (1) and the dipentaerythritol compound represented by the following chemical formula (2), R is represented by¹Preferably, the alkyl group has only a branched chain. When substituted with a branched alkyl group, the ester group is less likely to react with moisture or the like mixed in the refrigeration cycle, and thus a refrigerator oil less likely to deteriorate can be obtained.

Further, as a general refrigerating machine oil, besides the polyol ester oil, a polyalkylene glycol oil, a paraffin mineral oil, a naphthene mineral oil, a polyalphaolefin oil, a soft alkylbenzene oil, and the like are known. However, the oil may contain trifluoroiodomethane (CF)₃I) When the mixed refrigerant of (3) is used in combination with the refrigerant, it is difficult to ensure sufficient thermal stability and chemical stability, and the mixed refrigerant is used in combination with the refrigerantIt is not appropriate to mix the refrigerant and use the refrigerating machine oil.

The kinematic viscosity of the refrigerating machine oil of the refrigerating cycle device at 40 ℃ is preferably 22mm²Over s and 84mm²The ratio of the water to the water is less than s. Such a kinematic viscosity allows the refrigerant to be sufficiently compatible with the refrigerant even at low temperatures, and thus can be used without any problem in various types of hermetic electric compressors. The lubricating property of the sliding part of the compressor and the sealing property of the compression chamber can be properly ensured regardless of the form of the compressor.

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 the refrigerator 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.

In a state of being enclosed in a refrigeration cycle together with a refrigerant, the refrigerating machine oil-water content of the refrigeration cycle apparatus is preferably kept at 300 ppm by weight or less. In general, the moisture content of the refrigerator oil is reduced during manufacturing. However, water is mixed into the refrigerating machine oil when the compressor is charged, or enters the refrigerating cycle when the refrigerating cycle apparatus is manufactured. When the refrigeration cycle apparatus is operated, such water is locally present mainly in a phase of the refrigerator oil rather than in a phase of the refrigerant.

When the water content of the refrigerator oil is reduced to 300 ppm by weight or less, the water content is reduced by reaction with trifluoroiodomethane (CF)₃I) The reaction amount of the refrigerating machine oil becomes extremely small, and decomposition of trifluoroiodomethane and deterioration of the refrigerating machine oil are greatly suppressed. As a result, trifluoromethane (CHF) is also inhibited₃) The amount of production of (c). Since the total amount of trifluoromethane produced can be suppressed and the durability of the adsorbent can be improved, the deterioration of the mixed refrigerant itself and the deterioration of the refrigerating machine oil can be suppressed for a long period of time.

In a state of being enclosed in the refrigeration cycle together with the refrigerant, the water content of the refrigerator oil is more preferably 200 ppm by weight or less, still more preferably 150 ppm by weight or less, and particularly preferably 100 ppm by weight or less. As the moisture content of the refrigerating machine oil decreases, deterioration of the mixed refrigerant itself and deterioration of the refrigerating machine oil can be continuously suppressed.

The moisture content of the refrigerating machine oil can be reduced by, for example, a drying process of the refrigerating machine oil, adjustment of an atmosphere at the time of filling the refrigerating machine oil, a degree of decompression (degree of vacuum or the like) of evacuation performed on the refrigerating cycle at the time of filling the refrigerating machine oil, installation of a dryer and a drying agent in the refrigerating cycle, and the like. The above-mentioned methods of reducing the moisture content can be used in appropriate combination.

The water content of the refrigerator oil can be measured, for example, by collecting the refrigerator oil compatible with the refrigerant from the refrigeration cycle and measuring the water content by karl fischer coulometry. The moisture content (moisture content in oil) can be measured according to JIS K2275-3: 2015 "crude oil and petroleum products-determination of moisture-third section: karl fischer coulometry.

The low-temperature-side critical solution temperature of the refrigerating machine oil of the refrigerating cycle apparatus and the mixed refrigerant containing the three components is preferably-10 ℃ or lower. When the low-temperature side critical solution temperature is-10 ℃ or lower, the refrigerator oil and the refrigerant have sufficient compatibility, and the refrigerator oil and the refrigerant can be prevented from separating into two layers in the refrigeration cycle. Since the amount of oil returned to the compressor of the refrigerating machine oil is improved, the lubricating property of the sliding parts, the sealing property of the refrigerant, the cooling property of the sliding parts, and the like in the compressor can be appropriately maintained.

The low-temperature side critical solution temperature can be adjusted mainly by changing the composition of the refrigerator oil. The low-temperature side critical solution temperature can be measured by the compatibility test method defined in JIS K2211. The contents were observed by sealing the refrigerator oil and the refrigerant in a pressure-resistant glass container and changing the temperature. When the contents were cloudy, the solution separated into two layers, and when the contents were transparent, it could be judged that the two layers were compatible. The temperature at which the solution separates into two layers can be solved as the low-temperature side critical solution temperature.

The refrigerating machine oil for a refrigeration cycle apparatus may contain a lubricity improver, an antioxidant, a stabilizer, an acid scavenger, an antifoaming agent, a metal deactivator, and the like as additives. In particular, from the viewpoint of preventing corrosion of the inner surface of the copper pipe, it is preferable to add a metal deactivator such as benzotriazole.

As the lubricity improver, an extreme pressure agent composed of a thermochemically stable tertiary phosphoric acid-based compound, for example, tricresyl phosphate, triphenyl phosphate, trixylyl phosphate, cresyldiphenyl phosphate, 2-ethylhexyl phosphate, tris (2-ethylhexyl) phosphate, and the like can be used.

When an extreme pressure agent is added as an additive, the extreme pressure agent is preferably 0.1 mass% or more and 2.0 mass% or less with respect to the refrigerator oil. However, the polyol ester oil had good lubricity even without the addition of an extreme pressure agent. Furthermore, phosphate esters such as tertiary phosphate esters are easily accompanied by trifluoroiodomethane (CF)₃I) Is decomposed in the presence of a degradation factor generated by the decomposition of (2). Therefore, when the polyol ester oil is used as the refrigerating machine oil, the extreme pressure agent may not be added.

As the antioxidant, for example, a phenol-based antioxidant such as DBPC (2, 6-di-t-butyl-p-cresol) can be used. In general, it can be said that the refrigerator oil is an environment in which the antioxidant is hardly consumed. However, in the case of using a catalyst containing trifluoroiodomethane (CF)₃I) In the case of the mixed refrigerant of (3), iodic acid (HIO) functioning as an oxidizing agent is generated along with the decomposition of trifluoroiodomethane₃) And the like. Therefore, it is preferable to add an antioxidant to the refrigerator oil. The antioxidant is preferably 0.1 mass% or more and 21.0 mass% or less with respect to the refrigerator oil.

Examples of the acid scavenger include alicyclic epoxy compounds, aliphatic epoxy compounds, and monoterpene compounds. The alicyclic epoxy compound remained for a long period of time in the refrigeration cycle and showed an effect of suppressing an increase in the total acid value. The aliphatic epoxy compound reacts with moisture at a low temperature, and thus moisture contained in the refrigerating machine oil can be quickly captured at the initial stage of operation of the refrigeration cycle apparatus. Furthermore, the complex trifluoroiodomethane (CF) can be efficiently captured₃I) Acid substances generated by decomposition of (1).

Examples of the alicyclic epoxy compound include: 1, 2-epoxycyclohexane, 1, 2-epoxycyclopentane, 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate, bis (3, 4-epoxycyclohexylmethyl) 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-epoxyethyl-1, 2-epoxycyclohexane, and the like.

The alicyclic epoxy compound is particularly preferably a 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane carboxylate represented by the following chemical formula (3).

Chemical formula 3

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). [ wherein, in the chemical formula (4), R²Represents an alkyl group having 4 to 12 carbon atoms.]

Chemical formula 4

Examples of the alkyl glycidyl ether compound include compounds represented by the following chemical formula (5). [ wherein, in the chemical formula (5), R³Represents an alkyl group having 4 to 12 carbon atoms.]

Chemical formula 5

As R²、R³The alkyl group may be either a linear alkyl group or a branched alkyl group. As R²、R³Specific examples of (3) include n-butyl and iso-butylButyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, 1-ethylpentyl, isohexyl, 2-ethylhexyl, and the like.

Examples of the monoterpene compound include monocyclic monoterpenes, polycyclic monoterpenes, and acyclic monoterpenes. As the monoterpene compound, monocyclic monoterpenes are preferable. Examples of the monocyclic monoterpenes include limonene, α -pinene, β -pinene, and γ -pinene.

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

Next, trifluoromethane (CHF) used in the refrigeration cycle apparatus according to the present embodiment is adsorbed₃) The adsorbent of (4) will be described in detail.

< adsorbent >

As the adsorbent, for example, a adsorbent capable of adsorbing trifluoromethane (CHF) can be used₃) The pores of (2) and a porous material having polarity. The adsorbent is preferably an adsorbent having pores with a size not larger than the effective diameter of trifluoromethane and larger than the effective diameter of a refrigerant component such as trifluoroiodomethane, a refrigerating machine oil, an additive, or the like. That is, it is preferable that trifluoromethane is selectively adsorbed, and that it is difficult to adsorb refrigerant components such as trifluoroiodomethane that is larger than trifluoromethane, refrigerator oil, additives, and the like.

The form of the adsorbent may be any of powder, block, sphere, plate, scale, fiber, whole block, and the like. For example, the adsorbent in powder form or the like can be contained in an outer package formed of a nonwoven fabric, a resin mesh, a metal mesh, a breathable film, or the like, and can be installed in the refrigeration cycle. The adsorbent may contain a binder, a carrier, and the like in addition to the active ingredient for adsorbing trifluoromethane.

Specific examples of the adsorbent include alumina (Al)₂O₃) Zeolites such as silica alumina, activated carbon, and molecular sieves 5A, XH-10. Examples of the alumina include α -alumina and γ -alumina (activated alumina). The alumina may be synthetic alumina obtained by Bayer process, other thermal decomposition method, etc,Sintered alumina (alumina ceramics), and the like. One or more kinds of the adsorbent may be used.

As the adsorbent, alumina is preferable, and activated alumina is particularly preferable. Activated alumina having a predetermined pore diameter selectively adsorbs trifluoromethane (CHF)₃) The capacity of (2) is higher. On the other hand, the moisture contained in a small amount in the mixed refrigerant can be selectively removed by a dryer on the refrigeration cycle. Therefore, if activated alumina having an appropriate pore diameter is used as the adsorbent, trifluoromethane in the refrigeration cycle can be selectively and efficiently removed.

In general, as forms of activated alumina, powder, lump, spherical, and the like are widely known. The center particle diameter of the common activated alumina is about 1 μm to 10 mm. As the adsorbent, such appropriate activated alumina can be used. The form and particle size of the activated alumina used as the adsorbent are not particularly limited, and may be commercially available or classified into a predetermined pore distribution.

Selective adsorption of trifluoromethane (CHF)₃) From the viewpoint of (2), the pore diameter of the adsorbent is preferably 0.5 to 1.0nm, more preferably 0.6 to 0.9 nm. Also, the specific surface area of the adsorbent is preferably more than 100m²A/g, more preferably 150m²More than g. The pore volume of the adsorbent is preferably 0.3cm³More than g. The larger the specific surface area and pore volume of the adsorbent such as activated alumina, the larger the amount of adsorption per unit weight of the adsorbent, and thus trifluoromethane in the refrigeration cycle can be removed efficiently and continuously.

The specific surface area and pore volume of the adsorbent can be determined by the BET1 point method. The BET method is a method of solving the amount of adsorption of a gas based on adsorption of a monolayer of the gas on the surface of a sample using a BET formula representing the relationship between the amount of adsorption at equilibrium and pressure. In the BET1 point method, an approximation of the BET formula is performed assuming that the condensation coefficient is significantly larger than 1, and one measurement result is substituted into the approximation formula to be calculated.

In the BET method, if the pressure at the time of adsorption is assumed to be about a saturated vapor pressure, a phenomenon in which gas adsorbed in pores changes to a liquid phase due to a capillary condensation phenomenon can be utilized. 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 adsorption gas for measurement, nitrogen gas, argon gas, or the like can be used.

The adsorbent is preferably subjected to pretreatment in order to increase the activity of the surface. For example, by charging the adsorbent in a vacuum oven at 220 ℃ for 5 hours, the adsorption of R23 on the adsorbent surface can be improved by removing the gas molecules and moisture adsorbed on the surface. The pretreatment temperature is preferably 150 ℃ to 300 ℃ or lower. The pretreated adsorbent is stored in a dryer or the like in advance.

According to the refrigeration cycle apparatus of the present embodiment, trifluoroiodomethane (CF) is used as the refrigerant₃I) The mixed refrigerant of (1), wherein trifluoromethane (CHF) is adsorbed by the gas phase portion in the refrigeration cycle₃) The adsorbent of (3), therefore, can effectively and continuously suppress an increase in the concentration of trifluoromethane associated with deterioration of the refrigerant. Even when the operation of the refrigeration cycle apparatus is continued, the concentration of trifluoromethane can be suppressed, and the GWP of the mixed refrigerant can be prevented from increasing. Further, since the refrigeration cycle is provided with the dryer, decomposition of trifluoroiodomethane itself which generates trifluoromethane and deterioration of the refrigerator oil can be continuously suppressed. The adsorbent for adsorbing trifluoromethane and the desiccant used in the dryer are appropriately disposed separately in the refrigeration cycle, and the respective adsorption targets can be efficiently adsorbed by effectively utilizing the individual adsorption capacities. For example, the combination of a desiccant having an effective diameter of the adsorption object of less than or equal to that of water and an adsorbent having an effective diameter of the adsorption object of less than or equal to that of trifluoromethane can reduce competitive adsorption of water and trifluoromethane. Therefore, the performance and safety of the refrigeration cycle apparatus can be appropriately maintained for a long period of time, and a refrigeration cycle apparatus having high environmental compatibility and reliability can be provided.

While the embodiments of the refrigeration cycle apparatus of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical scope. For example, the above-described embodiments are not limited to the embodiments having all the configurations described above. Further, a part of the structure of one embodiment may be replaced with another structure, or another structure may be added to the structure of one embodiment. Further, as for a part of the configuration related to the embodiment, addition of another configuration, deletion of the configuration, and replacement of the configuration can be performed.

For example, in the above-described embodiment, a multi-type air conditioner for a high-rise building is shown as a specific example of the refrigeration cycle apparatus, but the refrigeration cycle apparatus of the present invention can be applied to an indoor air conditioner and a combined air conditioner having one indoor unit. The refrigeration cycle apparatus of the present invention can 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 apparatus, and the like.

The present invention will be specifically described below by way of examples, but the technical scope of the present invention is not limited thereto.

< examples 1 to 4 >

To evaluate trifluoromethane (CHF)₃) The amount of the compound (C) tends to be smaller than that of the compound (C) containing trifluoroiodomethane (CF)₃I) The combination of the mixed refrigerant of (3) and various refrigerator oils was subjected to an accelerated deterioration test by heating.

As the refrigerant, difluoromethane (HFC32), pentafluoroethane (HFC125) and trifluoroiodomethane (CF) were used₃I) The weight ratio of HFC32 to HFC125 to CF in the case of a multi-connected air conditioner for a high-rise building₃Mixed refrigerant of I50: 10: 40.

As the refrigerating machine oil, polyol ester oil shown below (notation POE) or polyvinyl ether oil shown below (notation PVE) was used. Further, 0.3 wt% of DBPC as an antioxidant was blended in each of the refrigerator oils. 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane carboxylate as an alicyclic epoxy compound and an alkyl glycidyl ester compound as an aliphatic epoxy compound were blended in a total amount of 0.5% by weight. Further, 1.0% by weight of tricresyl phosphate (TCP) was added to the polyvinyl ether oil alone.

(notation POE) hindered polyol ester oil (mixed fatty acid ester oil of pentaerythritol-based 2-ethylhexanoic acid/3, 5, 5-trimethylhexanoic acid, kinematic viscosity at 40 ℃ of 64.9mm²/s)

(notation PVE) polyvinyl ether oil (a copolymer ether oil of an alkoxyvinyl polymer, the aldoxy group being an ethyloxy group and an isobutyloxy group, having a kinematic viscosity of 66.8mm at 40 ℃²/s)

(accelerated deterioration test)

The accelerated degradation test was performed in the following order. First, a Polytetrafluoroethylene (PTFE) vessel was placed in a cleaned pressure vessel (pressure resistance: maximum 20MPa, internal volume: 220 mL). Then, 60g of refrigerator oil and a metal catalyst were added to the PTFE container. The water content (water content in oil) in the refrigerator oil is adjusted to less than 100 ppm by weight or to 500ppm by weight.

The water content in the oil was measured by Karl Fischer's coulometry in accordance with JIS K2275-3. As the metal catalyst, aluminum, copper and iron (diameter: 2.0mm, length: 300mm) were ground with sand paper, and after washing with acetone and ethanol, they were wound into a coil shape and put in.

Next, the pressure vessel containing the refrigerator oil and the metal catalyst was depressurized to 100Pa or less and evacuated, and then 12g of a refrigerant was introduced and sealed. Then, the pressure vessel was placed in a constant temperature bath and heated at 150 ℃ for 504 hours. After heating, the pressure vessel was opened, and the total acid value of the refrigerator oil and the amount of iodine in the refrigerator oil (amount of iodine in oil) were measured. Iodine content in oil is expressed as originating from trifluoroiodomethane (CF)₃I) The amount of iodine component in the decomposed refrigerator oil of (2) is an index of decomposition of the refrigerant itself and deterioration of the refrigerator oil or the like.

According to JIS K2501: 2003 "Petroleum products and lubricating oils-neutralization test method" to determine the total acid number. Further, the amount of iodine in the oil was measured by combustion type ion chromatography. Burning the test oil at 1000 deg.C, with peroxideThe iodine component was collected with hydrogen water, and then the sample liquid was injected into an ion chromatograph, and the eluent was transferred and measured with a conductivity detector. As the eluent, Na was used₂CO₃/NaHCO₃And (4) mixing the solution. The flow rate of the eluent was set to 1.5 mL/min.

Before and after the accelerated degradation test, the gas in the PTFE container was collected from the gas-side valve of the thermostatic bath into a sampling bag (Tedlar bag), and then the residual amount of the acid scavenger and the gas composition were quantitatively analyzed by gas chromatography.

Table 1 below shows the analysis results of the type of the refrigerator oil, the amount of water in the refrigerator oil (amount of water in oil), the total acid value of the refrigerator oil, the amount of iodine in the refrigerator oil (amount of iodine in oil), the residual amount of the acid scavenger, and the gas composition of the sample.

TABLE 1

As shown in table 1, in examples 1 and 2, the refrigerating machine oil was a polyol ester oil, but the increase of the total acid value of the refrigerating machine oil from the initial value (0.01mgKOH/g or less) was small, and the deterioration of the refrigerating machine oil was sufficiently suppressed. Iodine content in oil is below detection sensitivity, and trifluoroiodomethane (CF) is inhibited₃I) Decomposition of (3). The residual amount of the acid scavenger was high, and it was confirmed that the deterioration factor was suppressed. As a result of analyzing the gas composition of the sample, trifluoromethane (CHF) was confirmed₃) Is in trace amount.

On the other hand, in examples 3 and 4, the refrigerator oil was a polyvinyl ether oil, but the total acid value of the refrigerator oil was large, and deterioration of the refrigerator oil tended to progress to some extent. The iodine content in the oil was higher, suggesting that trifluoroiodomethane (CF) was accompanied₃I) The iodine component is sucked into the oil. The residual amount of the acid scavenger was 0, and almost complete consumption was confirmed. As a result of analyzing the gas composition of the sample, trifluoromethane (CHF) was produced to some extent₃) This suggests that the decomposition of trifluoroiodomethane proceeds.

From the results shown in Table 1, it was confirmed that trifluoroiodomethane (CF) was contained when heated in the coexistence of refrigerator oil₃I) The mixed refrigerant of (1) is subjected to trifluoromethane (CHF)₃) And (4) generating. As a catalyst with a compound containing trifluoroiodomethane (CF)₃I) The refrigerator oil used in combination with the mixed refrigerant of (1) is preferably polyol ester oil (POE) as compared with polyvinyl ether oil (PVE).

< examples 5 to 11 >

To evaluate adsorption of trifluoromethane (CHF) by the adsorbent in the presence of a mixed refrigerant₃) Performance of each adsorbent, adsorption tests of each adsorbent were performed.

As the refrigerant, a mixed refrigerant in the case of the multi-type air conditioner for a high-rise building, which is the same as the above-described accelerated degradation test, is used. Trifluoromethane (CHF) is added to the mixed refrigerant₃) The concentration of the reaction solution was adjusted to 3000 ppm.

As the adsorbent, activated alumina, activated carbon, and a molecular sieve different in particle size, pore volume, and specific surface area from each other are used. The activated alumina is classified into activated alumina "D-201" (manufactured by UNION SHOWAY Co., Ltd., sieve 7 to 12, particle size 1.6 to 3.0mm) using an adsorbent for dehydration and impurity removal. As the activated carbon, granular activated carbon "4 GG for gas phase" (manufactured by As-1 Co., Ltd., 4mm granules) was used. As the molecular sieve, molecular sieve XH-10 (pore diameter 0.8nm) was used.

(adsorption test)

The adsorption test was performed in the following order. First, a PTFE container was placed in a cleaned pressure vessel (pressure resistance: maximum 20MPa, internal volume: 220 mL). Then, 5g of the adsorbent was added to the PTFE container. Next, the pressure vessel containing the adsorbent was depressurized to 100Pa or less and evacuated, and then 8g of refrigerant was introduced and sealed. Then, the pressure vessel was placed in a constant temperature bath and allowed to stand at 20 ℃ for 168 hours.

Thereafter, the gas in the PTFE container was collected from the gas-side valve of the thermostatic bath into a sampling bag (Tedlar bag), and thereafter trifluoromethane (CHF) was subjected to gas chromatography₃) Was quantitatively analyzed. During the adsorption test, the reaction is adjusted to be inertThe operation of each adsorbent was performed in a glove box under an inert gas atmosphere.

The types of adsorbents, center particle diameters, pore volumes, specific surface areas, and trifluoromethane (CHF) after adsorption test are shown in table 2 below₃) The result of analysis of the concentration of (2).

TABLE 2

As shown in Table 2, trifluoromethane (CHF) after the adsorption test in examples 5 to 11₃) All concentrations were below the initial value (3000 ppm). Trifluoromethane (CHF) after adsorption test in examples 8 and 9 using activated alumina having a large specific surface area₃) The concentration of (3) was particularly low, and it was confirmed that the adsorption effect was high.

< example 12 >

A durability test was performed for 3000 hours under high-speed and high-load conditions for a refrigeration cycle apparatus in which an adsorbent was placed in an accumulator and a refrigeration cycle apparatus in which no adsorbent was placed.

As the refrigeration cycle apparatus, an apparatus equipped with a scroll-type hermetic electric compressor, that is, an apparatus for a multi-type air conditioner for a high building having a cooling capacity of 28kW is used. The rotation speed of the compressor is 6000min^-1. In the insulation of the core and the coil of the motor, a heat-resistant PET film (B type, temperature index: 130 ℃ C.) having a thickness of 250 μm was used. The coil uses a double-coated copper wire coated with a polyester imide-amide imide double coating.

As the refrigerant, a mixed refrigerant of a multi-type air conditioner for a high-rise building, which is assumed to be the same as the above-described accelerated degradation test, was used. 8000g of refrigerant is sealed in the refrigeration cycle. As the refrigerating machine oil, polyol ester oil shown in the same (notation POE) as in the accelerated degradation test was used. As shown in fig. 3, the adsorbent is disposed in the gas phase portion in the container of the accumulator. As the adsorbent, activated alumina was used.

As a dryer, a container filled with molecular sieve XH-10 (pore diameter 0.8nm) was set on the freezing cycle. In a refrigeration cycle apparatus having an adsorbent disposed in an accumulator, 1500mL of a refrigerating machine oil dehydrated to 200 ppm by weight or less in water content is sealed in a compressor. On the other hand, in the refrigeration cycle apparatus not provided with the adsorbent, 1500mL of the refrigerator oil in which the water content in the oil was adjusted to 600 ppm by weight was sealed in the compressor.

The refrigeration cycle apparatus in which the adsorbent was placed in the accumulator and the refrigeration cycle apparatus in which the adsorbent was not placed were operated for 3000 hours. Thereafter, the gas in each accumulator was collected from the gas recovery port in the upper part of the accumulator into a sampling bag (Tedlar bag), and trifluoromethane (CHF) was subjected to gas chromatography₃) Was quantitatively analyzed.

As a result, in the refrigeration cycle apparatus not provided with the adsorbent, trifluoromethane (CHF) in the gas collected from the accumulator₃) Is about 4500 ppm. In contrast, in a refrigeration cycle apparatus in which an adsorbent is disposed in an accumulator, the amount of the adsorbent is reduced to 500ppm or less.

From the above results, it was confirmed that trifluoroiodomethane (CF) was used₃I) In the refrigeration cycle apparatus using a mixed refrigerant according to (1), trifluoromethane (CHF) is adsorbed₃) The adsorbent of (2) can suppress the concentration of trifluoromethane for a long period of time by being provided in the gas phase portion of the refrigeration cycle.

Claims

1. A refrigeration cycle device is provided with: a compressor that compresses a refrigerant; a condenser for condensing the refrigerant compressed by the compressor; a decompressor for decompressing the refrigerant condensed by the condenser; an evaporator that evaporates the refrigerant decompressed by the decompressor; an accumulator that separates and temporarily accumulates liquid droplets from the refrigerant containing the liquid droplets evaporated by the evaporator; and a dryer for removing moisture from the refrigerant,

the above-described refrigeration cycle apparatus is characterized in that,

the refrigerant is a mixed refrigerant containing trifluoroiodomethane, has a vapor pressure at 25 ℃ of 1.1 to 1.8MPa,

the compressor is a hermetic electric compressor, which comprises a compression mechanism part and a motor for driving the compression mechanism part in a hermetic container, and is filled with refrigerating machine oil for lubricating a sliding part,

the energy storage device is provided with an adsorbent for adsorbing trifluoromethane.

2. The refrigeration cycle apparatus according to claim 1,

the adsorbent is disposed above an inlet through which the refrigerant flows into the accumulator.

3. A refrigeration cycle device is provided with: a compressor that compresses a refrigerant; a condenser for condensing the refrigerant compressed by the compressor; a decompressor for decompressing the refrigerant condensed by the condenser; an evaporator that evaporates the refrigerant decompressed by the decompressor; an accumulator that separates and temporarily accumulates liquid droplets from the refrigerant containing the liquid droplets evaporated by the evaporator; a dryer that removes moisture from the refrigerant; and a storage tank which adjusts a remaining refrigerant,

the above-described refrigeration cycle apparatus is characterized in that,

the storage tank is provided with an adsorbent for adsorbing trifluoromethane.

4. The refrigeration cycle apparatus according to claim 3,

the adsorbent is disposed at an upper portion in the storage tank or above an inlet port through which the refrigerant flows into the storage tank.

5. The refrigeration cycle apparatus according to any one of claims 1 to 4,

the refrigerator oil is a polyol ester oil.

6. The refrigeration cycle apparatus according to any one of claims 1 to 4,

the adsorbent is alumina.

7. The refrigeration cycle apparatus according to claim 6,

the alumina is gamma-alumina.

8. The refrigeration cycle apparatus according to claim 7,

the specific surface area of the gamma-alumina is more than 100m²/g。