REFRIGERATION CYCLE DEVICE AND HEAT CYCLE SYSTEM

Abstract

A refrigeration cycle apparatus includes a compressor, a condenser, a pressure reducing mechanism and an evaporator and use a working fluid containing a hydrofluoroolefin (HFO). The compressor, condenser, pressure reducing mechanism and evaporator are connected with a pipeline to form a refrigeration cycle. A deoxidizing portion where the working fluid is brought into contact with a desiccant or a deoxidizer is provided at any place within the refrigeration cycle.

Description

TECHNICAL FIELD

The present invention relates to a refrigeration cycle apparatus and a heat cycle system.

BACKGROUND ART

The following cooling cycle apparatus has been known in the background art: in the cooling cycle apparatus, a cooling compressor in which a refrigerator oil has been enclosed, a first heat exchanger, a refrigerant flow rate control portion such as a capillary tube and an expansion valve, a second heat exchanger placed in a space portion to be refrigerated or air-conditioned, and an accumulator are connected with a pipeline so as to constitute a refrigeration cycle; a single working fluid of a hydrofluoroolefin (HFO) or a mixed working fluid including a hydrofluoroolefin as its basic component is enclosed in the refrigerant cycle; and an adsorber which has been filled with an adsorbent for adsorbing substances having hydrofluoric acid as their main ingredient is provided in the cooling cycle (for example, see Patent Document 1).

Similarly, the following refrigeration apparatus is known: a working fluid including a mixture of a hydrofluoroolefin having a carbon-carbon double bond as its basic ingredient and a hydrofluorocarbon (HFC) having no double bond circulates; the refrigeration apparatus has a configuration including a working fluid circulating passage where the working fluid circulates, and a hydrogen fluoride capturing portion which stores a hydrogen fluoride capturing agent; the working fluid circulating passage starts at a compressor and comes back to the compressor through a condenser, an expansion mechanism and an evaporator; and the hydrogen fluoride capturing portion is disposed in the working fluid circulating passage (for example, see Patent Document 2).

In the configurations described in Patent Documents 1 and 2, a hydrofluoroolefin is used as a working fluid. When the hydrofluoroolefin is decomposed by the effect of water or oxygen, hydrofluoric acid is generated in a cooling cycle or a refrigeration cycle, causing deterioration of use components. In Patent Documents 1 and 2, the generated hydrofluoric acid is removed to prevent the deterioration of the use components in the cooling cycle or the refrigeration cycle.

CITATION LIST

Patent Document

Patent Document 1: WO 2010/047116 A1

Patent Document 2: JP 2010-270957 A

SUMMARY OF THE INVENTION

Technical Problems

However, an HFO has a property capable of being self-decomposed when there is an ignition source under high temperature or high pressure.

Although the use of an HFO-containing working fluid as a working fluid for a refrigeration cycle and a heat cycle has been studied, it is necessary to take a measure against a fear that the HFO may react due to its reactivity depending on the condition of the apparatus, for example, the temperature of the use environment, conditions of oxygen or the like, the presence of an ignition source or the like.

In the configurations of Patent Documents 1 and 2, the hydrofluoric acid generated finally within the cycle is removed, but the presence of water or oxygen within the cycle is allowed. Decomposition of the HFO is advanced by the effect of the water or oxygen under a high-temperature atmosphere, and thus, an acid is more likely to be generated. The acid generated by the decomposition of the HFO corrodes metal components within the cycle to form inorganic sludge of metal salt. The inorganic sludge itself serves as a catalyst promoting the decomposition of the HFO.

When sludge is generated in the refrigeration cycle, the refrigerant flow rate control portion may be clogged with the sludge. Thus, there is a problem that the reliability of the compressor is extremely spoiled.

Therefore, an object of the present invention is to provide a refrigeration cycle apparatus and a heat cycle system using an HFO as a working fluid, in which water or oxygen is removed from a cycle to avoid generation of sludge so that safe operation can be performed in spite of the use of the HFO.

Solution to Problems

In order to solve the above problem(s), the refrigeration cycle apparatus in an aspect of the present invention is a refrigeration cycle apparatus including a compressor, a condenser, a pressure reducing mechanism and an evaporator, which are connected with a pipeline to form a refrigeration cycle, and using a working fluid containing a hydrofluoroolefin (HFO), wherein:

a deoxidizing portion where the working fluid is brought into contact with a desiccant or a deoxidizer is provided at any place within the refrigeration cycle.

A heat cycle system in another aspect of the present invention is mounted with the refrigeration cycle apparatus.

Advantageous Effects of the Invention

In the present invention, it is possible to avoid generation of sludge within a refrigeration cycle so that safe operation can be performed in spite of the use of a working fluid containing an HFO.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall configuration diagram illustrating an example of a refrigeration cycle apparatus in an embodiment of the present invention.

FIG. 2 is a view illustrating an example of a deoxidizing portion in the refrigeration cycle apparatus in the embodiment of the present invention.

FIG. 3 is a view illustrating an example of a deoxidizing portion having another configuration from that of FIG. 2.

FIG. 4 is a view illustrating an example of a deoxidizing portion having another configuration from those of FIG. 2 and FIG. 3.

FIG. 5 is a view illustrating an air conditioning apparatus which is an example of a heat cycle system in an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Embodiment for carrying out the present invention are described below with reference to the drawings.

FIG. 1 is an overall configuration diagram illustrating an example of a refrigeration cycle apparatus in the embodiment of the present invention. As illustrated in FIG. 1, the refrigeration cycle apparatus in the embodiment includes a compressor 10, a condenser 20, a pressure reducing mechanism 30, an evaporator 40, a deoxidizing portion 50, and a pipeline 60. The compressor 10, the condenser 20, the pressure reducing mechanism 30, the evaporator 40 and the deoxidizing portion 50 are connected in an annular shape by the pipeline 60 so as to form a refrigeration cycle as a whole. In addition, in the refrigeration cycle apparatus in the embodiment, a working fluid containing an HFO is used as a working fluid. The details of the working fluid are described later. If water or oxygen is included within the refrigeration cycle, the HFO may be easily decomposed to generate sludge. The refrigeration cycle apparatus in the embodiment includes a configuration for avoiding generation of such sludge. Specific contents of the configuration are described below.

The compressor 10 plays a role of compressing a low-temperature and low-pressure gaseous working fluid to form it into a high-temperature and high-pressure gaseous working fluid. The high-temperature and high-pressure gaseous working fluid is sent to the condenser 20.

The condenser 20 plays a role of condensing the high-temperature and high-pressure gaseous working fluid sent from the compressor 10 to thereby form it into a liquid working fluid. The liquid working fluid is sent to the deoxidizing portion 50. In the condenser 20, heat of the gaseous working fluid is radiated into the air.

The deoxidizing portion 50 plays a role of removing oxygen from the working fluid. Here, the oxygen means an oxygen component, that is, an O component, and oxygen O₂ and an oxygen component O contained in water H₂O also fall within the range of the meaning thereof. The deoxidizing portion 50 internally has a desiccant or a deoxidizer. The working fluid passing through the inside of the deoxidizing portion 50 is brought into contact with the desiccant or the deoxidizer to thereby remove the oxygen component from the working fluid. As a result, generation of sludge within the refrigeration cycle can be avoided.

The deoxidizing portion 50 may be provided at any place within the refrigeration cycle. The deoxidizing portion 50 can remove the oxygen component from the working fluid even if the deoxidizing portion 50 is provided at any place. However, in consideration of efficiency in removing oxygen, the deoxidizing portion 50 is preferably provided between the condenser 20 and the pressure reducing mechanism 30. In a place between the condenser 20 and the pressure reducing mechanism 30 where the working fluid is in a state as a liquid working fluid, the working fluid can be efficiently brought into contact with the desiccant or the deoxidizer. That is, the working fluid which is in a state as a gaseous working fluid diffuses so that the working fluid cannot always surely contact with the desiccant or the deoxidizer even if the desiccant or the deoxidizer is included inside the deoxidizing portion 50. However, the working fluid which is in the state as a liquid working fluid is highly likely to surely contact with the desiccant or the deoxidizer if the desiccant or the deoxidizer is provided in a flow path.

Specific configurations of the deoxidizing portion 50 are described in detail later.

The pressure reducing mechanism 30 plays a role of converting the liquid refrigerant, which has been sent through the deoxidizing portion 50 or directly from the condenser 20, into a low-temperature and low-pressure wet vapor. Thus, the liquid working fluid is converted into a gaseous working fluid again. The pressure reducing mechanism 30 which expands the working fluid due to reduction in pressure may be also referred to as an expansion mechanism 30.

The evaporator 40 plays a role of evaporating the refrigerant gas, which is a low-temperature and low-pressure wet vapor sent from the pressure reducing mechanism 30, to thereby form the refrigerant gas into a low-temperature and low-pressure gaseous working fluid. In the evaporator 40, the gaseous working fluid is evaporated due to heat absorbed from its surroundings.

The low-temperature and low-pressure gaseous working fluid sent from the evaporator 40 is sucked into the compressor 10, and compressed into a high-temperature and high-pressure gaseous working fluid again.

Thereafter, the aforementioned refrigeration cycle starting at the compressor 10 is repeated. Thus, heat radiation from the working fluid and heat absorption of the refrigerant are performed repeatedly.

The basic refrigeration cycle is performed by the refrigerant circulating in the compressor 10, the condenser 20, the pressure reducing mechanism 30 and the evaporator 40. The deoxidizing portion 50 plays a role of removing the oxygen component generated in the refrigeration cycle to thereby avoid generation of sludge in the refrigeration cycle. Accordingly, the deoxidizing portion 50 may be placed at any place within the refrigeration cycle.

Next, a configuration of an example of the deoxidizing portion 50 is described with reference to FIG. 2. FIG. 2 is a view illustrating a configuration of an example of the deoxidizing portion 50 in the refrigeration cycle apparatus in the embodiment of the present invention.

As illustrated in FIG. 2, the deoxidizing portion 50 has a tubular member 51, an inlet 52, an outlet 53, an inlet-side flow surface 54, an outlet-side flow surface 55, a deoxidizer holding portion 56, and a deoxidizer 57.

The tubular member 51 is a tubular member forming the external shape of the deoxidizing portion 50. The tubular member 51 is connected to the pipeline 60 and designed as a part of a flow path of the refrigeration cycle.

The inlet 52 and the outlet 53 serve as an inlet and an outlet of the refrigerant. The inlet 52 and the outlet 53 are opposite end portions connected to the pipeline 60. That is, the inlet 52 and the outlet 53 of the deoxidizing portion 50 are connected in series with the pipeline 60 so that the deoxidizing portion 50 forms a part of the flow path of the refrigeration cycle.

The inlet-side flow surface 54 and the outlet-side flow surface 55 are a pair of surfaces which are arranged so that the working fluid can circulate therebetween. The inlet-side flow surface 54 and the outlet-side flow surface 55 are provided to be bonded to the inner circumferential surface of the tubular member 51. The inlet-side flow surface 54 and the outlet-side flow surface 55 are shaped so that the working fluid is allowed to flow therethrough. For example, each of the inlet-side flow surface 54 and the outlet-side flow surface 55 is configured to have network openings like a mesh, a lattice or the like.

A space between the inlet-side flow surface 54 and the outlet-side flow surface 55 is configured as a deoxidizer holding portion 56. The deoxidizer holding portion 56 is a region that holds the deoxidizer 57. Accordingly, the openings forming the networks of the inlet-side flow surface 54 and the outlet-side flow surface 55 are preferably formed as openings each smaller than the particle size of the deoxidizer 57 so that the deoxidizer 57 can be held in the region within the deoxidizer holding portion 55.

The deoxidizer 57 is a granular chemical agent for removing oxygen from the refrigerant. As the deoxidizer 57, various deoxidizers 57 can be used as long as they can remove oxygen from the refrigerant. Iron powder may be, for example, used as the deoxidizer 57.

A desiccant may be used as the deoxidizer 57 as described previously. As for the desiccant, various desiccants can be used as long as they can remove water from the refrigerant. Examples of such desiccants include anhydrous calcium sulfide, calcium chloride, barium oxide, phosphorus pentaoxide, activated alumina, silica gel, and molecular sieves. In this case, the deoxidizer holding portion 56 serves as a desiccant holding portion 56. The deoxidizer holding portion 56 and the desiccant holding portion 56 may be collectively referred to as a chemical agent holding portion 56.

In addition to the deoxidizer 57, a hydrogen fluoride capturing agent for removing hydrogen fluoride from the working fluid may be used. Any agent may be used as the hydrogen fluoride capturing agent as long as it can react with hydrogen fluoride. It is, however, preferable to select an agent in which a byproduct produced by the reaction capturing hydrogen fluoride rarely has an adverse effect within the refrigeration cycle. Among such agents, it is preferable to use one kind of calcium carbonate, calcium oxide and calcium hydroxide which can react with hydrogen fluoride without causing reverse reaction, or a combination of some kinds of those.

Each of the inlet-side flow surface 54 and the outlet-side flow surface 55 may have a network-like shape, and may be a permeable member or a fibrous structure, which allows the working fluid to pass therethrough, as long as it allows the working fluid to flow therethrough.

FIG. 3 is a view illustrating an example of a deoxidizing portion 50a having a different configuration from that of FIG. 2. The deoxidizing portion 50a has a tubular member 51, an inlet 52, an outlet 53, an inlet-side flow surface 54 and a deoxidizer 57 in the same manner as the deoxidizing portion 50 in FIG. 2. However, different from the deoxidizing portion 50 in FIG. 2, the deoxidizing portion 50a does not have the outlet-side flow surface 55 but has a bag-like deoxidizer holding portion 56a. In this manner, the deoxidizer holding portion 56a may be formed into a bag-like shape so that the deoxidizer 57 can be held in the bag. In this case, the deoxidizer holding portion 56a may have a cloth-like shape or may have a network-like shape.

Although FIG. 3 illustrates an example in which the outlet-side flow surface 55 is not provided, the configuration of FIG. 3 may be arranged to further include the outlet-side flow surface 55.

The deoxidizer 57 may be a desiccant in the same manner as described in FIG. 1 and FIG. 2.

FIG. 4 is a view illustrating an example of a deoxidizing portion 50b having a different configuration from those of FIG. 2 and FIG. 3. The deoxidizing portion 50b has an inlet 52, an outlet 53, a deoxidizer holding portion 56 and a deoxidizer 57 in the same manner as the deoxidizing portion 50 in FIG. 2. However, the deoxidizing portion 50b has a different configuration from that of the deoxidizing portion 50 in FIG. 2, as to a tubular member 51a, an inlet-side flow surface 54a and an outlet-side flow surface 55a. In addition, the deoxidizing portion 50b is different from the deoxidizing portion 50 in FIG. 2, as to the point that a strainer mesh 58 is newly provided inside the tubular member 51a.

First, the tubular member 51a has an upstream tubular member 51b and a downstream tubular member 51c having different tube diameters from each other. The upstream tubular member 51b is arranged to be thicker than the downstream tubular member 51c. The downstream end of the upstream tubular member 51b is connected to the upstream end of the downstream tubular member 51c so as to integrally form the tubular member 51a.

The inlet-side flow surface 54a and the outlet-side flow surface 55a are provided in the downstream tubular member 51c, and the deoxidizer holding portion 56 is formed between the inlet-side flow surface 54a and the outlet-side flow surface 55a. The deoxidizer 57 is held inside the deoxidizer holding portion 56. This point is similar to that of the deoxidizing portion 50 in FIG. 2. The deoxidizing portion 50b in FIG. 4 is different from the deoxidizing portion 50 in FIG. 2 at the point that the inlet-side flow surface 54a and the outlet-side flow surface 55a are formed out of strainer meshes. Each of the strainer meshes forming the inlet-side flow surface 54a and the outlet-side flow surface 55a plays a role of fixing the deoxidizer 57 in the same manner as the inlet-side flow surface 54 and the outlet-side flow surface 55 in the deoxidizing portion 50 in FIG. 2. The mesh roughness is not arranged to be extremely fine. For example, it is preferable to use strainer meshes of about 100 meshes.

On the other hand, the strainer mesh 58 is provided in the upstream tubular member 51b. It is preferable that the strainer mesh 58 is arranged to have finer meshes than the strainer mesh constituting each of the inlet-side flow surface 54a and the outlet-side flow surface 55a, so that sludge can be captured on the upstream side. The tube diameter of the upstream tubular member 51b is larger than the tube diameter of the downstream tubular member 51c. Therefore, the area of the strainer mesh 58 is larger than the area of each of the inlet-side flow surface 54a and the outlet-side flow surface 55a. Accordingly, even when the strainer mesh 58 is clogged with sludge, the clogging partially occurs, and there is few case that the whole of the strainer mesh 58 is clogged. Thus, the strainer mesh 58 can play a role of capturing sludge, and the sludge can be prevented from adhering to the surface of the deoxidizer 57.

In this manner, the inlet-side flow surface 54a and the outlet-side flow surface 55a may be arranged as strainer meshes while the strainer mesh 58 for capturing sludge is further provided on the upstream side.

Alternatively, without providing the strainer mesh 58 on the upstream side, the inlet-side flow surface 54 and the outlet-side flow surface 55 in the deoxidizing portion 50 in FIG. 2 may be arranged as strainer meshes similarly to the inlet-side flow surface 54a and outlet-side flow surface 55a provided in the downstream tubular member 51c in FIG. 4.

In any configuration of the deoxidizing portions 50, 50a and 50b, a desiccant may be used in place of the deoxidizer 57 as described above.

In this manner, each deoxidizing portion 50, 50a, 50b may be arranged in various configurations as long as the working fluid can pass through the deoxidizing portion 50, 50a, 50b while contacting with the deoxidizer 57 or the desiccant. In addition, a suitable configuration may be used in consideration of whether the working fluid is gaseous or liquid, or a configuration which can support both a liquid working fluid and a gaseous working fluid may be used. The configurations illustrated in FIG. 2 to FIG. 4 can be applied to both the liquid working fluid and the gaseous working fluid.

In this manner, the refrigeration cycle apparatus in the embodiment includes the deoxidizing portion 50 within the refrigeration cycle so that water and oxygen within the refrigeration cycle can be removed to avoid generation of sludge. Accordingly, generation of sludge can be avoided in spite of the use of an HFO which is easily dissolved by water and oxygen as the refrigerant.

In addition, the refrigeration cycle apparatus in the embodiment can be used in a heat cycle system such as an air conditioning apparatus. Description is made below about an example in which the compressor 10, the condenser 20, the pressure reducing mechanism 30, the evaporator 40 and the deoxidizing portion 50 of the refrigeration cycle system in FIG. 1 are applied to a compressor 10a, an indoor heat exchanger 20a, an expansion valve 30a, an outdoor heat exchanger 40a and a deoxidizing portion 50c, respectively, to thereby form an air conditioning apparatus 150.

FIG. 5 is a view illustrating an example of the air conditioning apparatus 150 which is an example of a heat cycle system in the embodiment of the present invention.

As illustrated in FIG. 5, the air conditioning apparatus 150 includes an outdoor unit 150a and an indoor unit 150b. The compressor 10a serving as a compression mechanism, a four-way selector valve 154, the expansion valve 30a serving as an expansion (pressure reducing) mechanism, a release valve 159, and the outdoor heat exchanger 40a, which are provided in the outdoor unit 150a, are connected with a pipeline 60a to the indoor heat exchanger 20a provided in the indoor unit 150b so as to form a refrigerant circulating passage 61. In addition, the deoxidizing portion 50c is provided between the indoor heat exchanger 20a and the expansion valve 30a and inside the outdoor unit 150a. The deoxidizing portion 50c may contain a desiccant or may contain a deoxidizer 57. In addition, any one of the configurations of the deoxidizing portions 50, 50a and 50b illustrated in FIG. 2 to FIG. 4 may be used as the configuration of the deoxidizing portion 50c, or another configuration may be used. Since the deoxidizing portion 50c is provided within the heat cycle system, decomposition of the HFO within the heat cycle can be inhibited to thereby avoid generation of sludge.

A fan 160 is provided in the outdoor heat exchanger 40a, and a fan 161 is provided in the indoor unit 150b. The outdoor and indoor units are cooled by the air blown by the fans 160 and 161 respectively. The release valve 159 is provided on the side of the outdoor unit 150a. The release valve 159 is an emergency valve which can release a refrigerant circulating in the passage 61 to the outdoor unit 150a (to the outside of the apparatus).

In the air conditioning apparatus 150, the circulating direction of the refrigerant can be reversed, i.e. cooling and heating operation can be performed, by the switching operation of the four-way selector valve 154. That is, in the air conditioning apparatus 150, the compressor 10a, the outdoor heat exchanger 40a of the outdoor unit 150a (heat source side), the expansion valve 30a, and the indoor heat exchanger 20a of the indoor unit 150b (use side) are connected sequentially to form the working fluid passage 61 in which the working fluid can circulate reversibly.

The air conditioning apparatus 150 also includes a control device 170, various sensors S1 to S8 disposed on the passage 61 or in the respective units, and a power supply device 172 such as an inverter power source for supplying electric power to the compressor 10a based on power supply from an AC power source 171.

The sensors S1 and S2 are sensors that detect (sense) leakage of the refrigerant to the outside of the passage 61. The sensor S1 is provided inside the outdoor unit 150a. The sensor S2 is provided inside the indoor unit 150b.

The sensor S3 is a sensor that detects the temperature of the working fluid flowing through a discharge pipe of the compressor 10a. The sensor S4 is a sensor that detects the temperature of the working fluid flowing through the pipeline 60a between the heat exchanger 40a on the heat source side and the expansion valve 30a. The sensor S5 is a sensor that detects the opening degree of the expansion valve 30a. The sensor S6 is a sensor that detects the temperature of a motor (not shown) serving as a driving portion for the compressor 10a. The sensors S7 and S8 are sensors which are disposed before and after the expansion valve 30a (that is, at an input terminal and an output terminal thereof) so as to detect the flow rate of the working fluid circulating in the passage 61 (inside the pipeline 60a).

The control device 170 controls the aforementioned respective members (the compressor 10a, the four-way selector valve 154, the expansion valve 30a, the release valve 159, the outdoor heat exchanger 40a, the indoor heat exchanger 20a, and the fans 160 and 161) based on detection information detected by the various sensors S1 to S8. Specifically, the control device 170 drives and controls the power supply device 172 supplying electric power to the motor of the compressor 10a so as to drive the compressor 10a. The release valve 159 is openably/closably provided in the pipeline 58 branching from the passage 61 to the outside of the unit. The release valve 159 is normally closed. The release valve 159 is opened by the control device 170 when an avoiding operation is performed.

Here, a schematic running operation of the air conditioning apparatus 150 is described.

In a heating operation, the four-way selector valve 154 is set as illustrated by the solid line in FIG. 5. When the compressor 10a is operated in this state, the indoor heat exchanger 20a serves as the condenser 20 in FIG. 1 and the outdoor heat exchanger 40a serves as the evaporator 40 in FIG. 1. Thus, a refrigeration cycle is established.

The high pressure refrigerant discharged from the compressor 10a passes through the four-way selector valve 154 (at a dot d2 in FIG. 5), and flows into the indoor heat exchanger 20a. The high pressure refrigerant radiates heat to the indoor air and is condensed (at a dot d3 in FIG. 5). On this occasion, the condensed high pressure refrigerant passes through the deoxidizing portion 50c, and an oxygen component is removed from the high pressure refrigerant. The high pressure refrigerant which has passed through the deoxidizing portion 50c flows into the expansion valve 30a. Thus, the pressure of the high pressure refrigerant is reduced by the expansion valve 30a to be formed into a low pressure refrigerant (at a dot d4 in FIG. 5). Then, the low pressure refrigerant flows into the outdoor heat exchanger 40a.

The low pressure refrigerant flowing into the outdoor heat exchanger 40a absorbs heat from the outdoor air and is evaporated. The evaporated low pressure refrigerant passes through the four-way selector valve 154, and is sucked into the compressor 10a via the dot d1 in FIG. 5. Then, the sucked low pressure refrigerant is compressed and discharged again as a high pressure refrigerant. This operation is repeated to perform the heating operation of the air conditioning apparatus 150.

In each of the indoor heat exchanger 20a and the outdoor heat exchanger 40a in the air conditioning apparatus 150, the flow of the working fluid during a cooling operation and the flow of the working fluid during the heating operation are in opposite directions to each other. For example, in the indoor heat exchanger 20a and the outdoor heat exchanger 40a, during the cooling operation, so-called counter-current flows are formed so that the inlet side of the working fluid serves as the outlet side of the air while the outlet side of the working fluid serves as the inlet side of the air. During the heating operation, the inlet side of the working fluid serves as the inlet side of the air while the outlet side of the working fluid serves as the outlet side of the air. On that occasion, another deoxidizing portion 50c may be further provided between the outdoor heat exchanger 40a and the expansion valve 30a. The deoxidizing portion 50c may be arranged to be used not only for a liquid refrigerant but also for a gaseous working fluid so that the gaseous working fluid can be dried or deoxidized in the deoxidizing portion 50c between the indoor heat exchanger 20a and the expansion valve 30a. In addition, although FIG. 5 has been described along an example in which the deoxidizing portion 50c is provided between the indoor heat exchanger 20a and the expansion valve 30a, the deoxidizing portion 50c may be provided at any place within the heat cycle.

In this manner, when the deoxidizing portion 50c is provided in the heat cycle system such as the air conditioning apparatus 150, an oxygen component can be removed from the heat cycle system to thereby avoid generation of sludge within the heat cycle.

Next, description is made about the refrigerant for use in the refrigeration cycle apparatus and the heat cycle system in the embodiment of the present invention.

As described above, the working fluid for use in the refrigeration cycle apparatus and the heat cycle system in the embodiment of the present invention contains a hydrofluoroolefin (HFO). Examples of such HFOs include trifluoroethylene (HFO-1123), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2-difluoroethylene (HFO-1132), 2-fluoropropene (HFO-1261yf), 1,1,2-trifluoropropene (HFO-1243yc), trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(E)), cis-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z)), trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)) and 3,3,3-trifluoropropene (HFO-1243zf). The working fluid preferably contains HFO-1234yf, HFO-1234ze(E) or HFO-1234ze(Z), more preferably contains HFO-1234yf or HFO-1123, and particularly preferably contains HFO-1123.

The working fluid used in the invention preferably contains HFO-1123, and may further contain, if necessary, optional components that are described later. The content of HFO-1123 based on 100 mass % of the working fluid is preferably 10 mass % or more, more preferably from 20 to 80 mass %, further more preferably from 40 to 80 mass %, and still further more preferably from 40 to 60 mass %.

(HFO-1123)

The properties of HFO-1123 as working fluid are shown in Table 1 particularly by relative comparison with R410A (a pseudoazeotropic mixture refrigerant of HFC-32 and HFC-125 in a mass ratio of 1:1). Cycle performance is evaluated by a coefficient of performance and refrigeration capacity obtained by methods that are described later. The coefficient of performance and the refrigeration capacity of HFO-1123 are expressed by relative values (hereinafter referred to as relative coefficient of performance and relative refrigeration capacity) based on those of R410A as reference (1.000). The global warming potential (GWP) is a 100-years value shown in Intergovernmental Panel on Climate Change (IPCC), Fourth assessment report (2007), and measured in accordance with the method of the same report. In the present specification, GWP means the value unless otherwise specified. When the working fluid is formed of a mixture, the temperature gradient is a significant factor for evaluating the working fluid, as described later. It is preferable that the value of the temperature gradient is smaller.

	TABLE 1
	R410A	HFO-1123
	Relative coefficient of performance	1.000	0.921
	Relative refrigeration capacity	1.000	1.146
	Temperature gradient [° C.]	0.2	0
	GWP	2088	0.3

[Optional Components]

The working fluid used in the present invention preferably contains HFO-1123. In addition to HFO-1123, any optional compounds that are usually used as working fluids may be contained as long as they do not impair the effect of the present invention. Examples of such optional compounds (optional components) include HFCs, HFOs (HFCs each having a carbon-carbon double bond) other than HFO-1123, and other components that can be vaporized or liquefied together with HFO-1123. Preferred optical components are HFCs, and HFOs (HFCs each having a carbon-carbon double bond) other than HFO-1123.

Such an optical component is preferably a compound which can set the GWP or the temperature gradient within an acceptable range while enhancing the relative coefficient of performance and the relative refrigeration capacity when it is, for example, used in a heat cycle together with HFO-1123. When the working fluid contains such a compound together with HFO-1123, better cycle performance can be obtained while keeping the GWP low, and the influence of the temperature gradient can be reduced.

(Temperature Gradient)

When the working fluid contains, for example, HFO-1123 and an optical component, the working fluid has a significant temperature gradient as long as HFO-1123 and the optional component do not form an azeotropic composition. The temperature gradient of the working fluid depends on the kind of the optional component and the mixture ratio between HFO-1123 and the optional component.

Usually, when a mixture is used as the working fluid, an azeotropic mixture or a pseudoazeotropic mixture such as R410A is preferably used. A non-azeotropic composition has a problem that a change in composition occurs when the composition is charged into a refrigerator/air-conditioner from a pressure vessel. Further, when a refrigerant leaks from the refrigerator/air-conditioner, there is an extremely great possibility that the composition of the refrigerant within the refrigerator/air-conditioner may change so that the composition of the refrigerant cannot be recovered to its initial state easily. On the other hand, the problem can be avoided if the working fluid is an azeotropic or pseudoazeotropic mixture.

The “temperature gradient” is generally used as an index to evaluate availability of a mixture in the working fluid. The temperature gradient is defined as such a property that the initiation temperature and the completion temperature of evaporation in a heat exchanger such as an evaporator or of condensation in a heat exchanger such as a condenser differ from each other. The temperature gradient is 0 in an azeotropic mixture, and the temperature gradient is very close to 0 in a pseudoazeotropic mixture. For example, the temperature gradient of R410A is 0.2.

When the temperature gradient is large, there is a problem that the inlet temperature, for example, in the evaporator decreases so that frosting is more likely to occur. Further, generally in a heat cycle system, a working fluid flowing in a heat exchanger and a heat source fluid such as water or air are made to flow as counter-current flows against each other in order to improve the heat exchange efficiency. Since the temperature difference of the heat source fluid is small in a stable operation state, it is difficult to obtain a heat cycle system with a good energy efficiency in the case of a non-azeotropic mixture fluid with a large temperature gradient. Accordingly, when a mixture is used as the working fluid, it is desired that the working fluid has an appropriate temperature gradient.

(HFC)

As for the HFC as the optional component, it is preferable to select an HFC from the aforementioned viewpoint. Here, an HFC is known to have a high GWP as compared with HFO-1123. Accordingly, as the HFC used in combination with HFO-1123, it is preferable to select an HFC appropriately in order not only to improve cycle performance as the working fluid and set the temperature gradient within a proper range but also to adjust particularly the GWP within an acceptable range.

As an HFC which has less influence on the ozone layer and which has less influence on global warming, an HFC having 1 to 5 carbon atoms is specifically preferred. The HFC may be linear, branched or cyclic.

Examples of the HFC include HFC-32, difluoroethane, trifluoroethane, tetrafluoroethane, HFC-125, pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, heptafluorocyclopentane and the like.

Among them, in view of less influence on the ozone layer and excellent refrigeration cycle performance, preferable examples of the HFC include HFC-32, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoroethane (HFC-134a) and HFC-125, and more preferable examples thereof include HFC-32, HFC-152a, HFC-134a and HFC-125.

One kind of HFC may be used alone or two or more kinds of HFCs may be used in combination.

The content of the HFC in the working fluid (100 mass %) may be desirably selected depending on required properties of the working fluid. When the working fluid is, for example, made of HFO-1123 and HFC-32, the coefficient of performance and the refrigeration capacity can be improved when the content of HFC-32 falls within the range of from 1 to 99 mass %. When the working fluid is made of HFO-1123 and HFC-134a, the coefficient of performance can be improved when the content of HFC-134a falls within the range of from 1 to 99 mass %.

With respect to GWP of the aforementioned preferred HFC, GWP of HFC-32 is 675, GWP of HFC-134a is 1,430, and GWP of HFC-125 is 3,500. In order to reduce the GWP of the obtainable working fluid, HFC-32 is the most preferable HFC as the optional component.

HFO-1123 and HFC-32 can form a pseudoazeotropic mixture close to an azeotropic mixture when the mass ratio between the both is from 99:1 to 1:99. The mixture of the both has a temperature gradient close to 0 substantially without selecting a composition range thereof. Also with respect to this point, HFC-32 is advantageous as an HFC to be combined with HFO-1123.

When HFC-32 is used together with HFO-1123 in the working fluid used in the present invention, specifically the content of HFC-32 based on 100 mass % of the working fluid is preferably 20 mass % or more, more preferably from 20 to 80 mass %, and further preferably from 40 to 60 mass %.

When the working fluid used in the present invention, for example, contains HFO-1123, an HFO other than HFO-1123 is preferably HFO-1234yf (GWP=4), HFO-1234ze(E) or HFO-1234ze(Z) (GWP=6 in both the (E)-isomer and the (Z)-isomer), and more preferably HFO-1234yf or HFO-1234ze(E) because they are high in critical temperature and excellent in durability and coefficient of performance. One kind of HFOs other than HFO-1123 may be used alone, or two or more kinds of them may be used in combination. The content of the HFO other than HFO-1123 in the working fluid (100 mass %) may be desirably selected depending on required properties of the working fluid. When the working fluid is, for example, made of HFO-1123 and HFO-1234yf or HFO-1234ze, the coefficient of performance can be improved when the content of HFO-1234yf or HFO-1234ze falls within the range of from 1 to 99 mass %.

When the working fluid used in the present invention contains HFO-1123 and HFO-1234yf, a preferred composition range is shown below as a composition range (S).

In the respective formulae showing the composition range (S), the abbreviation of each compound designates the proportion (mass %) of the compound to the total amount of HFO-1123, HFO-1234yf and other components (HFC-32 and the like).

HFO-1123+HFO-1234yf≥70 mass %

95 mass %≥HFO-1123/(HFO-1123+HFO-1234yf)≥35 mass %  <Composition Range (S)>

The working fluid in the composition range (S) is extremely low in GWP and small in temperature gradient. In addition, refrigeration cycle performance high enough to replace the R410A in the background art can be exhibited also from the viewpoint of the coefficient of performance, the refrigeration capacity and the critical temperature.

In the working fluid in the composition range (S), the proportion of HFO-1123 to the total amount of HFO-1123 and HFO-1234yf is more preferably from 40 to 95 mass %, further more preferably from 50 to 90 mass %, particularly preferably from 50 to 85 mass %, and most preferably from 60 to 85 mass %.

In addition, the total content of HFO-1123 and HFO-1234yf in 100 mass % of the working fluid is more preferably from 80 to 100 mass %, further more preferably from 90 to 100 mass %, and particularly preferably from 95 to 100 mass %.

In addition, it is preferable that the working fluid used in the present invention contains HFO-1123, HFC-32 and HFO-1234yf. A preferred composition range (P) in a case where the working fluid contains HFO-1123, HFC-32 and HFO-1234yf is shown below.

In the respective formulae showing the composition range (P), the abbreviation of each compound designates the proportion (mass %) of the compound to the total amount of HFO-1123, HFO-1234yf and HFC-32. The same thing can be also applied to a composition range (R), a composition range (L) and a composition range (M). In addition, in the following composition range, it is preferable that the total amount of HFO-1123, HFO-1234yf and HFC-32 described specifically is more than 90 mass % and 100 mass % or less based on the entire amount of the working fluid for the heat cycle.

70 mass %≤HFO-1123+HFO-1234yf

30 mass %≤HFO-1123≤80 mass %

0 mass %<HFO-1234yf≤40 mass %

0 mass %<HFC-32≤30 mass %

HFO-1123/HFO-1234yf≤95/5 mass %  <Composition Range (P)>

The working fluid having the above composition range is a working fluid having respective properties of HFO-1123, HFO-1234yf and HFC-32 in a balanced manner, and avoiding defects of the respective components. That is, the working fluid is a working fluid which has an extremely low GWP, and has a small temperature gradient and a certain performance and efficiency when used for the heat cycle, and thus, favorable cycle performance is obtained by the working fluid. Here, it is preferable that the total amount of HFO-1123 and HFO-1234fy is 70 mass % or more based on the total amount of HFO-1123, HFO-1234yf and HFC-32.

A more preferred composition as the working fluid used in the present invention may be a composition containing HFO-1123 in an amount of from 30 to 70 mass %, HFO-1234yf in an amount of from 4 to 40 mass %, and HFC-32 in an amount of from 0 to 30 mass %, based on the total amount of HFO-1123, HFO-1234yf and HFC-32 and having a content of HFO-1123 in a proportion of 70 mol % or less based on the entire amount of the working fluid. The working fluid within the aforementioned range is a working fluid in which self-decomposition reaction of HFO-1123 is inhibited to enhance the durability in addition to the aforementioned effect enhanced. From the viewpoint of the relative coefficient of performance, the content of HFC-32 is preferably 5 mass % or more, and more preferably 8 mass % or more.

Other preferred compositions in the case where the working fluid used in the present invention contains HFO-1123, HFO-1234yf and HFC-32 is shown below. A working fluid in which self-decomposition reaction of HFO-1123 is inhibited to enhance the durability can be obtained as long as the content of HFO-1123 is 70 mol % or less based on the entire amount of the working fluid.

A more preferred composition range (R) is shown below.

10 mass %≤HFO-1123<70 mass %

0 mass %<HFO-1234yf≤50 mass %

30 mass %<HFC-32≤75 mass %  <Composition Range (R)>

The working fluid having the above composition is a working fluid having respective properties of HFO-1123, HFO-1234yf and HFC-32 in a balanced manner, and avoiding defects of the respective components. That is, the working fluid is a working fluid which has a low GWP and ensures durability while having a small temperature gradient and having a high performance and efficiency when used for the heat cycle, and thus, favorable cycle performance is obtained by the working fluid.

A preferred range in the working fluid having the composition range (R) is shown below.

20 mass %≤HFO-1123<70 mass %

0 mass %<HFO-1234yf≤40 mass %

30 mass %<HFC-32≤75 mass %

The working fluid having the above composition is a working fluid having respective properties of HFO-1123, HFO-1234yf and HFC-32 in a balanced manner, and avoiding defects of the respective components. That is, the working fluid is a working fluid which has a low GWP and ensures durability, while having a smaller temperature gradient and having a higher performance and efficiency when used for the heat cycle, and thus, favorable cycle performance is obtained by the working fluid.

A more preferable range (L) in the working fluid having the composition range (R) is shown below. A composition range (M) is further more preferable.

10 mass %≤HFO-1123<70 mass %

0 mass %<HFO-1234yf≤50 mass %

30 mass %<HFC-32≤44 mass %  <Composition Range (L))

20 mass %≤HFO-1123<70 mass %

5 mass %≤HFO-1234yf≤40 mass %

30 mass %<HFC-32≤44 mass %  <Composition Range (M))

The working fluid having the composition range (M) is a working fluid having respective properties of HFO-1123, HFO-1234yf and HFC-32 in a balanced manner, and avoiding defects of the respective components. That is, the working fluid is a working fluid in which an upper limit of GWP is reduced to 300 or less and durability is ensured, and which has a small temperature gradient smaller than 5.8 and has a relative coefficient of performance and a relative refrigeration capacity close to 1 when used for the heat cycle, and thus, favorable cycle performance is obtained by the working fluid.

Within this range, the upper limit of the temperature gradient is decreased, and the lower limit of the product of the relative coefficient of performance and the relative refrigeration capacity is increased. In order to increase the relative coefficient of performance, it is more preferable to satisfy “8 mass %≤HFO-1234yf”. In addition, in order to increase the relative refrigeration capacity, it is more preferable to satisfy “HFO-1234yf≤35 mass %”.

In addition, it is preferable that another working fluid used in the present invention contains HFO-1123, HFC-134a, HFC-125 and HFO-1234yf. With this composition, flammability of the working fluid can be controlled.

More preferably in the working fluid containing HFO-1123, HFC-134a, HFC-125 and HFO-1234yf, the proportion of the total amount of HFO-1123, HFC-134a, HFC-125 and HFO-1234yf is more than 90 mass % and 100 mass % or less based on the entire amount of the working fluid, and the proportion of HFO-1123 is 3 mass % or more and 35 mass % or less, the proportion of HFC-134a is 10 mass % or more and 53 mass % or less, the proportion of HFC-125 is 4 mass % or more and 50 mass % or less, and the proportion of HFO-1234yf is 5 mass % or more and 50 mass % or less, based on the total amount of HFO-1123, HFC-134a, HFC-125 and HFO-1234yf. Such a working fluid is a working fluid being non-flammable, having excellent safety, having less influence on the ozone layer and global warming, and having excellent cycle performance when used for a heat cycle system.

Most preferably, in the working fluid containing HFO-1123, HFC-134a, HFC-125 and HFO-1234yf, the proportion of the total amount of HFO-1123, HFC-134a, HFC-125 and HFO-1234yf is more than 90 mass % and 100 mass % or less based on the entire amount of the working fluid, and the proportion of HFO-1123 is 6 mass % or more and 25 mass % or less, the proportion of HFC-134a is 20 mass % or more and 35 mass % or less, the proportion of HFC-125 is 8 mass % or more and 30 mass % or less, and the proportion of HFO-1234yf is 20 mass % or more and 50 mass % or less, based on the total amount of HFO-1123, HFC-134a, HFC-125 and HFO-1234yf. Such a working fluid is a working fluid being non-flammable, having more excellent safety, having much less influence on the ozone layer and global warming, and having more excellent cycle performance when used for the heat cycle system.

(Other Optional Components)

The working fluid used in a composition for the heat cycle system in the present invention may contain carbon dioxide, a hydrocarbon, a chlorofluoroolefin (CFO), a hydrochlorofluoroolefin (HCFO) and the like, other than the aforementioned optional component. As the other optional component, a component which has less influence on the ozone layer and has less influence on global warming is preferred.

Examples of the hydrocarbon include propane, propylene, cyclopropane, butane, isobutane, pentane, isopentane and the like.

One kind of such hydrocarbons may be used alone or two or more kinds of them may be used in combination.

When the working fluid contains a hydrocarbon, its content is less than 10 mass %, preferably from 1 to 5 mass %, and more preferably from 3 to 5 mass %, based on 100 mass % of the working fluid. When the content of the hydrocarbon is equal to or more than the lower limit, the solubility of a mineral refrigerator oil in the working fluid is more favorable.

Examples of the CFO include chlorofluoropropene, chlorofluoroethylene and the like. In order to easily control the flammability of the working fluid without significantly decreasing the cycle performance of the working fluid, the CFO is preferably 1,1-dichloro-2,3,3,3-tetrafluoropropene (CFO-1214ya), 1,3-dichloro-1,2,3,3-tetrafluoropropene (CFO-1214yb) or 1,2-dichloro-1,2-difluoroethylene (CFO-1112).

One kind of such CFOs may be used alone or two or more kinds of them may be used in combination.

When the working fluid contains the CFO, its content is less than 10 mass %, preferably from 1 to 8 mass %, and more preferably from 2 to 5 mass %, based on 100 mass % of the working fluid. When the content of the CFO is equal to or more than the lower limit, the flammability of the working fluid can be easily controlled. When the content of the CFO is equal to or less than the upper limit, favorable cycle performance is likely to be obtained.

Examples of the HCFO include hydrochlorofluoropropene, hydrochlorofluoroethylene and the like. In order to easily control the flammability of the working fluid without significantly decreasing the cycle performance of the working fluid, the HCFO is preferably 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd) or 1-chloro-1,2-difluoroethylene (HCFO-1122).

One kind of such HCFOs may be used alone or two or more kinds of them may be used in combination.

In a case where the working fluid contains the HCFO, the content of the HCFO is less than 10 mass %, preferably from 1 to 8 mass %, and more preferably from 2 to 5 mass %, based on 100 mass % of the working fluid. When the content of the HCFO is equal to or more than the lower limit, the flammability of the working fluid can be easily controlled. When the content of the HCFO is equal to or less than the upper limit, favorable cycle performance is likely to be obtained.

When the working fluid used in the present invention contains the aforementioned other optional components, the total content of the other optional components in the working fluid is less than 10 mass %, preferably 8 mass % or less, and more preferably 5 mass % or more, based on 100 mass % of the working fluid.

In the refrigeration cycle apparatus and the heat cycle system 150 in the embodiment of the present invention, generation of sludge within the refrigeration cycle can be prevented to perform the refrigeration cycle operation stably in spite of such a working fluid having a tendency of self-decomposition.

Although the present invention has been described in detail and with reference to its specific embodiment, it is obvious for those skilled in the art that various changes or modifications can be made on the invention without departing from the spirit and scope thereof. The present application is based on a Japanese patent application No. 2016-3873 filed on Jan. 12, 2016, the contents of which are incorporated herein by reference.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

• • 10,10a Compressor
  • 20,20a Condenser
  • 30,30a Pressure reducing mechanism
  • 40,40a Evaporator
  • 50,50a,50b,50c Deoxidizing portion
  • 51,51a,51b,51c Tubular member
  • 52 Inlet
  • 53 Outlet
  • 54,54a Inlet-side flow surface
  • 55,55a Outlet-side flow surface
  • 56,56a Deoxidizer holding portion
  • 57 Deoxidizer
  • 58 Strainer mesh
  • 150 Heat cycle system

Claims

1. A refrigeration cycle apparatus including a compressor, a condenser, a pressure reducing mechanism and an evaporator, which are connected with a pipeline to form a refrigeration cycle, and using a working fluid containing a hydrofluoroolefin (HFO), wherein:

a deoxidizing portion where the working fluid is brought into contact with a desiccant or a deoxidizer is provided at any place within the refrigeration cycle.

2. The refrigeration cycle apparatus according to claim 1, wherein the deoxidizing portion is provided between the condenser and the pressure reducing mechanism.

3. The refrigeration cycle apparatus according to claim 1, wherein:

the deoxidizing portion is constituted as a tubular member whose opposite ends are connected to the pipeline within the refrigeration cycle, and

the deoxidizing portion includes:

an inlet-side flow surface through which a refrigerant is allowed to flow; and

a chemical agent holding portion which is provided on a downstream side of the inlet-side flow surface and holds the desiccant or the deoxidizer.

4. The refrigeration cycle apparatus according to claim 3, wherein the inlet-side flow surface has a network-like shape.

5. The refrigeration cycle apparatus according to claim 3, wherein:

the deoxidizing portion further includes an outlet-side flow surface through which the working fluid is allowed to flow, and has the chemical agent holding portion between the inlet-side flow surface and the outlet-side flow surface.

6. The refrigeration cycle apparatus according to claim 5, wherein the outlet-side flow surface has a network-like shape.

7. The refrigeration cycle apparatus according to claim 3, wherein the chemical agent holding portion has a bag-like shape.

8. The refrigeration cycle apparatus according to claim 3, wherein a strainer mesh for capturing sludge is provided on an upstream side of the inlet-side flow surface.

9. The refrigeration cycle apparatus according to claim 8, wherein an area of the strainer mesh is larger than an area of the inlet-side flow surface.

10. The refrigeration cycle apparatus according to claim 1, wherein the HFO includes HFO-1123.

11. The refrigeration cycle apparatus according to claim 10, wherein the working fluid is a single refrigerant of HFO-1123, a mixed refrigerant of HFO-1123 and HFC-32, a mixed refrigerant of HFO-1123 and HFO-1234yf, or a mixed refrigerant of HFO-1123, HFO-1234yf and HFC-32.

12. A heat cycle system, which is mounted with the refrigeration cycle apparatus according to claim 1.