Working medium for heat cycle, composition for heat cycle system, and heat cycle system

Abstract

To provide a working medium which has cycle performance of being alternative to R410A while sufficiently suppressing effects on global worming, prevents a large increase in a load to a device compared to the case in which R410A is used, and can be continuously and stably used without special actions and a composition for heat cycle system containing the same, and a heat cycle system using the composition.SOLUTION: A working medium for heat cycle has a product of a relative coefficient of performance and a relative refrigerating capacity with respect to R410A of 0.820 or more in a reference refrigerating cycle of a coefficient of global warming of less than 300, an evaporation temperature of 0°C, a condensation temperature of 40°C, an overcooling degree of 5°C and an overheating degree of 5°C, and has a relative compressor discharge gas pressure of 1.100 or less, a lower limit of a combustion range by High Pressure Gas Safety Law method A of 5 vol.% or more, and a pressure of not exceeding 2.00 MPaG in combustion test by High Pressure Gas Safety Law method A at 0.98 MPaG and 250°C.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a working fluid for heat cycle, a composition for a heat cycle system containing the same, and a heat cycle system using the composition. [Background technology]

[0002] In this specification, for halogenated hydrocarbons, the abbreviation for the compound is written in parentheses after the compound name, but in this specification, the abbreviation will be used instead of the compound name as necessary. Traditionally, chlorofluorocarbons (CFCs) such as chlorotrifluoromethane and dichlorodifluoromethane, and hydrochlorofluorocarbons (HCFCs) such as chlorodifluoromethane have been used as refrigerants for refrigerators, refrigerants for air conditioners, working fluids for power generation systems (such as waste heat recovery power generation), working fluids for latent heat transport devices (such as heat pipes), and working fluids for heat cycle systems such as secondary cooling media. However, CFCs and HCFCs are currently subject to regulation due to their impact on the stratospheric ozone layer.

[0003] For these reasons, hydrofluorocarbons (HFCs), such as difluoromethane (HFC-32), tetrafluoroethane, and pentafluoroethane (HFC-125), which have less impact on the ozone layer, have come to be used as working fluids for heat cycle systems instead of CFCs and HCFCs. For example, R410A (a pseudo-azeotropic mixture refrigerant of HFC-32 and HFC-125 in a mass ratio of 1:1) has been a refrigerant that has been widely used in the past. However, it has been pointed out that HFCs may be a cause of global warming.

[0004] Due to its high refrigeration capacity, R410A has been widely used in ordinary air conditioners, such as packaged air conditioners and room air conditioners. However, its global warming potential (GWP) is high at 2088, and so there is a demand for the development of a low-GWP working fluid. In this regard, there is a demand for the development of a working fluid that can simply replace R410A and continue to be used in the equipment that has been used up until now.

[0005] Recently, expectations have been focused on hydrofluoroolefins (HFOs), i.e., HFCs that have carbon-carbon double bonds, which are working fluids that have little impact on the ozone layer and little impact on global warming because they have carbon-carbon double bonds and are easily decomposed by OH radicals in the atmosphere. In this specification, unless otherwise specified, saturated HFCs are referred to as HFCs and are used to distinguish them from HFOs. HFCs may also be specified as saturated hydrofluorocarbons.

[0006] As a working fluid using HFO, for example, Patent Document 1 discloses a technology relating to a working fluid using 1,1,2-trifluoroethylene (HFO-1123) that has the above-mentioned properties and provides excellent cycle performance. Patent Document 1 also discloses an attempt to produce a working fluid by combining HFO-1123 with various HFCs and HFOs for the purpose of improving the non-flammability and cycle performance of the working fluid. Similarly, Patent Document 2 discloses a technology relating to a working fluid using 1,2-difluoroethylene (HFO-1132).

[0007] However, Patent Documents 1 and 2 state that HFO-1123 and HFO-2123 are alternative candidates to R410A, and that they are intended to provide cycle performance, such as capacity and efficiency, equivalent to that of R410A, and that they are intended to provide a practical working fluid that does not increase the load on the device, such as temperature and pressure, during operation, and that can be used stably without the need for special measures. There is no knowledge or suggestion of combining -1132 with HFCs or other HFOs as a working fluid. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2012 / 157764 [Patent Document 2] International Publication No. 2012 / 157765 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to provide a working fluid for use in a heat cycle system, which has cycle performance enabling it to replace R410A while sufficiently suppressing the impact on global warming, does not significantly increase the load on the device compared to the case where R410A is used, and can be used continuously and stably without taking any special measures, a composition for a heat cycle system containing the working fluid, and a heat cycle system using the composition. [Means for solving the problem]

[0010] The present invention provides a working fluid for heat cycle, a composition for a heat cycle system, and a heat cycle system having the configurations described in the following [1] to

[10] .

[0011] [1] A working fluid for heat cycle comprising trifluoroethylene and 1,3,3,3-tetrafluoropropene, the working fluid having the following properties (A-1) to (E-1): (A-1) The global warming potential (100 years) according to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) is less than 300. (B-1) Relative refrigeration capacity (RQ R410A ) and the relative coefficient of performance (RCOP) calculated by the following formula (Y) R410A ) is greater than or equal to 0.820.

number

number

[0012] [2] The working medium of [1], wherein the global warming potential is 250 or less. [3] The working medium of [1] or [2], whose global warming potential is 200 or less. [4] The working medium according to any one of [1] to [3], wherein the product of the relative coefficient of performance (RCOPR410A) and the relative refrigeration capacity (RQR410A) is 0.900 or more. [5] The working medium of [4], wherein the product of the relative coefficient of performance (RCOPR410A) and the relative refrigeration capacity (RQR410A) is 0.950 or more. [6] The working medium according to any one of [1] to [5], wherein the relative pressure (RDPR410A) is 1,000 or less. [7] Any of the working media [1] to [6], which has no flammable range. [8] A composition for a heat cycle system, comprising the working fluid for a heat cycle according to any one of [1] to [7] and a refrigerating machine oil. [9] A heat cycle system using the composition for a heat cycle system of [8].

[10] The heat cycle system of [9], wherein the heat cycle system is a refrigeration or cooling device, an air conditioning device, a power generation system, a heat transport device or a secondary cooling machine. Effect of the Invention

[0013] According to the present invention, there can be provided a working fluid for use in a heat cycle system, which has cycle performance enabling it to replace R410A while sufficiently suppressing the impact on global warming, does not significantly increase the load on the device compared to the case where R410A is used, and can be used continuously and stably without taking any special measures, and a composition for a heat cycle system containing the same. The heat cycle system of the present invention is a heat cycle system to which a composition for a heat cycle system is applied, which can replace R410A without requiring any special measures for the device and has a small impact on global warming. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing an example of a reference refrigeration cycle system for evaluating the heat cycle system of the present invention. [Diagram 2]FIG. 2 is a cycle diagram in which the state change of the working medium in the refrigeration cycle system of FIG. 1 is plotted on a pressure-enthalpy diagram. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described. [Working medium] The working fluid for heat cycle of the present invention (hereinafter also simply referred to as "working fluid") has the following properties (A-1) to (E-1).

[0016] (A-1) The global warming potential (100 years) according to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) is less than 300. In the following explanation, the above global warming potential is also referred to as "GWP." (B-1) Relative refrigeration capacity (RQ R410A ) and the relative coefficient of performance (RCOP) calculated by the above formula (Y) R410A ) is 0.820 or more. In the following description, the above product is also referred to as "relative cycle performance (relative to R410A)" or simply "relative cycle performance".

[0017] (C-1) Relative pressure (RDP) calculated by the above formula (Z) R410A ) is less than or equal to 1.100. (D-1) The lower limit of the flammable range measured in accordance with Method A of the High Pressure Gas Safety Act is 5% by volume or more. Hereinafter, the lower limit of the flammable range is also referred to as the "lower flammable limit." (E-1) In a combustion test conducted under conditions of 0.98 MPaG and 250°C using equipment conforming to Method A for measuring the flammable range under the High Pressure Gas Safety Act, the pressure does not exceed 2.00 MPaG. Note that the "G" after the pressure unit MPa indicates gauge pressure. Hereinafter, the property of a pressure exceeding 2.00 MPaG in the above combustion test is referred to as "self-decomposing."

[0018] In the present invention, as described above, (A) GWP, (B) relative cycle performance (vs. R410A), (C) relative pressure (RDP R410AThe essential conditions for the working fluid are that it satisfies the above conditions (A-1) to (E-1) for each of (A) to (E). (A) to (E) are explained below.

[0019] (A) GWP GWP is an index that measures the impact of a working fluid on global warming. In this specification, the GWP of a mixture is a weighted average based on the composition mass. The GWP of R410A, which the working fluid of the embodiment of the present invention aims to replace, is 2088, which has a large impact on the global environment. On the other hand, the GWP of the working fluid of the embodiment of the present invention is less than 300 as specified in (A-1).

[0020] The working fluid of the embodiment of the present invention has cycle performance almost equivalent to that of R410A as described below, while having an extremely low GWP as described above, and is a working fluid that minimizes the impact on global warming. The GWP of the working fluid of the embodiment is preferably 250 or less, more preferably 200 or less, and particularly preferably 150 or less.

[0021] (B) Relative cycle performance (vs. R410A) Relative cycle performance (vs. R410A) is an index showing the cycle performance of a working fluid by comparing it with the cycle performance of R410A, which is the target of its replacement. Specifically, R410A has the following relative refrigeration capacity (RQ R410A ) and relative coefficient of performance (RCOP R410A Relative refrigeration capacity (RQ R410A ) and relative coefficient of performance (RCOP R410A ) as an index, it is possible to evaluate the capacity and efficiency of the working fluid in a balanced manner with a single index.

[0022] As shown in (B-1), the working fluid of the embodiment of the present invention has a relative cycle performance (relative to R410A) of 0.820 or more. By satisfying both the condition (A-1) and the condition (B-1), a working fluid can be obtained that has cycle performance almost equal to or greater than that of R410A, while having a significantly reduced impact on global warming. The relative cycle performance (relative to R410A) of the working fluid of the embodiment is preferably 0.900 or more, more preferably 0.950 or more, and particularly preferably 1.000 or more.

[0023] The upper limit of the relative cycle performance (vs. R410A) of the working fluid of the embodiment is not particularly limited.

[0024] Here, cycle performance is the performance required when applying a working medium to a thermal cycle, and is evaluated by the coefficient of performance and capacity. When the thermal cycle system is a refrigeration cycle system, the capacity is the refrigeration capacity. The refrigeration capacity (also referred to as "Q" in this specification) is the output in a refrigeration cycle system. The coefficient of performance (also referred to as "COP" in this specification) is the value obtained by dividing the output (kW) by the power (kW) consumed to obtain the output, and corresponds to the energy consumption efficiency. The higher the coefficient of performance, the greater the output can be obtained with a smaller input.

[0025] In the present invention, the above-mentioned relative cycle performance (relative to R410A) is used as an index, and a reference refrigeration cycle under the following temperature conditions (T) is used. The relative refrigeration capacity of the working fluid relative to R410A under these conditions is calculated by the following formula (X): R410A Similarly, the relative coefficient of performance of the working fluid to R410A under these conditions is calculated by the following formula (Y): R410A In the formulas (X) and (Y), the specimen represents the working medium to be relatively evaluated.

[0026] [Temperature condition (T)] Evaporation temperature: 0°C (however, in the case of a non-azeotropic mixture, the average temperature between the evaporation start temperature and the evaporation end temperature) Condensation temperature: 40°C (however, in the case of a non-azeotropic mixture, the average temperature between the condensation start temperature and the condensation end temperature) Supercooling degree (SC); 5℃ Superheat degree (SH); 5℃

[0027]

number

[0028] An example of a reference refrigeration cycle system used in the above evaluation is a refrigeration cycle system whose schematic configuration is shown in Fig. 1. Hereinafter, a method for determining the refrigeration capacity and coefficient of performance of a predetermined working medium using the refrigeration cycle system shown in Fig. 1 will be described.

[0029] The refrigeration cycle system 10 shown in Figure 1 is a system roughly configured to include a compressor 11 that compresses working medium vapor A to produce high-temperature, high-pressure working medium vapor B, a condenser 12 that cools and liquefies the working medium vapor B discharged from the compressor 11 to produce low-temperature, high-pressure working medium C, an expansion valve 13 that expands the working medium C discharged from the condenser 12 to produce low-temperature, low-pressure working medium D, an evaporator 14 that heats the working medium D discharged from the expansion valve 13 to produce high-temperature, low-pressure working medium vapor A, a pump 15 that supplies a load fluid E to the evaporator 14, and a pump 16 that supplies a fluid F to the condenser 12.

[0030] In the refrigeration cycle system 10, the following cycles (i) to (iv) are repeated. (i) The working medium vapor A discharged from the evaporator 14 is compressed by the compressor 11 to produce high-temperature, high-pressure working medium vapor B (hereinafter referred to as the "AB process"). (ii) The working fluid vapor B discharged from the compressor 11 is cooled by the fluid F in the condenser 12 and liquefied to become the low-temperature, high-pressure working fluid C. At this time, the fluid F is heated to become the fluid F', which is discharged from the condenser 12 (hereinafter referred to as the "BC process").

[0031] (iii) The working medium C discharged from the condenser 12 is expanded by the expansion valve 13 to produce a low-temperature, low-pressure condenser. The working medium is D (hereinafter referred to as the "CD process"). (iv) The working medium D discharged from the expansion valve 13 is heated by the load fluid E in the evaporator 14 to become a high-temperature, low-pressure working medium vapor A. At this time, the load fluid E is cooled to become a load fluid E', and is discharged from the evaporator 14 (hereinafter referred to as the "DA process").

[0032] The refrigeration cycle system 10 is a cycle system consisting of an adiabatic / isentropic change, an isenthalpic change, and an isobaric change. When the state change of the working medium is plotted on the pressure-enthalpy curve (curve) shown in Fig. 2, it can be expressed as a trapezoid with vertices A, B, C, and D.

[0033] The AB process is a process in which high-temperature, low-pressure working medium vapor A is adiabatically compressed in the compressor 11 to produce high-temperature, high-pressure working medium vapor B, and is indicated by the line AB in FIG. 2. As described later, the working medium vapor A is introduced into the compressor 11 in a superheated state, and the resulting working medium vapor B is also superheated vapor. R410A The compressor discharge gas pressure (discharge pressure) used in the calculation of ) is the pressure (DP) in state B in Figure 2, which is the maximum pressure in the refrigeration cycle. Note that the temperature in state B in Figure 2 is the compressor discharge gas temperature (discharge temperature), which is the maximum temperature in the refrigeration cycle.

[0034] The BC process is a process in which isobaric cooling is performed in the condenser 12 to convert high-temperature, high-pressure working medium vapor B into low-temperature, high-pressure working medium C, and is shown by line BC in Figure 2. The pressure at this time is the condensation pressure. Among the intersections of the pressure-enthalpy line and the BC line, the intersection T1 on the high enthalpy side is the condensation temperature, and the intersection T2 on the low enthalpy side is the condensation boiling point temperature.

[0035] The CD process is a process in which isenthalpic expansion is performed in the expansion valve 13 to convert the low-temperature, high-pressure working medium C into a low-temperature, low-pressure working medium D, and is indicated by line CD in FIG. If the temperature in medium C is denoted as T3, then T2-T3 is the degree of subcooling (SC) of the working medium in cycles (i) to (iv).

[0036] The DA process is a process in which isobaric heating is performed in the evaporator 14 to return the low-temperature, low-pressure working medium D to high-temperature, low-pressure working medium vapor A, and is shown by the DA line in Figure 2. The pressure at this time is the evaporation pressure. Among the intersections of the pressure-enthalpy line and the DA line, the intersection point T6 on the high-enthalpy side is the evaporation temperature. If the temperature of the working medium vapor A is shown as T7, then T7-T6 is the degree of superheat (SH) of the working medium in the cycles (i) to (iv). Note that T4 shows the temperature of the working medium D.

[0037] The Q and COP of the working medium are the enthalpy and h in the states A (after evaporation, high temperature and low pressure), B (after compression, high temperature and high pressure), C (after condensation, low temperature and high pressure), and D (after expansion, low temperature and low pressure). A , h B , h C , h D Using these, they can be calculated using the following equations (11) and (12), respectively. Assume there are no losses due to equipment efficiency, and no pressure losses in piping or heat exchangers.

[0038] The thermodynamic properties required to calculate the cycle performance of the working fluid can be calculated based on the generalized equation of state (Soave-Redlich-Kwong equation) based on the corresponding state principle and various thermodynamic equations. If the property values ​​are not available, calculations are performed using an estimation method based on the atomic group contribution method.

[0039] Q=h A -h D …(11) COP = Q / Compression work = (h A -h D ) / (h B -h A ) …(12)

[0040] The above (h A -h D ) corresponds to the output of the refrigeration cycle (kW), and (h B -h AThe compression work indicated by Q (power consumption), for example the amount of electricity required to operate the compressor, corresponds to the power consumed (kW). Also, Q indicates the capacity to refrigerate the load fluid, and the higher Q, the more work can be done in the same heat cycle system. In other words, a large Q indicates that the desired performance can be obtained with a small amount of working medium, making it possible to miniaturize the heat cycle system.

[0041] In addition, the relative refrigeration capacity (RQ R410A ) and relative coefficient of performance (RCOP R410A ) is the relative refrigeration capacity (RQ R410A ) is preferably 0.820 or more, and the relative coefficient of performance (RCOP R410A The relative refrigeration capacity (RQ) is preferably 0.960 or more. R410A ) is 0.950 or more, and the relative coefficient of performance (RCOP R410A ) is 0.980 or higher.

[0042] (C) Relative Pressure (RDP) R410A ) Relative Pressure (RDP R410A Relative Pressure (RDP) is an index that shows the load on the equipment of the working medium by comparing it with the load on the equipment of the R410A that is the target of replacement. R410A ) is the compressor discharge gas pressure (DP) when the reference refrigeration cycle under the above temperature condition (T) is operated using the working medium (sample), as shown in the following formula (Z). 検体 ) Compressor discharge gas pressure (DP R410A ) is expressed as a ratio value to

[0043]

number

[0044] As explained above, the compressor discharge gas pressure indicates the maximum pressure in the standard refrigeration cycle under the above temperature condition (T). Based on this value, the degree of pressure load on the equipment when actually operating a heat cycle system such as a refrigeration / freezing equipment or an air conditioning equipment using the working medium can be estimated.

[0045] The working fluid of the embodiment of the present invention is a relative pressure (RDP) R410A The relative pressure (RDP) of the working medium of the embodiment is 1.100 or less. R410A If the ratio (C-1) is 1.100 or less, when the working medium is used to operate a heat cycle system using a specified device under specified conditions, the pressure load on the device is almost the same as when the heat cycle system is operated using the same device under the same conditions using R410A. In other words, by satisfying the condition (C-1), the working medium of the embodiment can be used in a device using R410A as the working medium without any particular design change.

[0046] The relative pressure (RDP) of the working medium of the embodiment R410A ) is preferably 1.000 or less. R410A ) is not particularly limited in its lower limit.

[0047] (D) Lower Flammability Limit The lower flammability limit is the range of the volume concentration (%) of the working medium relative to the total amount of the working medium and air, at which the working medium can be flammable under specified conditions when mixed with air, that is, the lower limit of the flammability range. In the present invention, the flammability range is the flammability range measured in accordance with Method A of the High Pressure Gas Safety Act.

[0048] Measuring in accordance with Method A of the High Pressure Gas Safety Act includes measuring by Method A of the High Pressure Gas Safety Act, and also includes measuring by a method other than Method A, for example a measurement method that has been modified to the extent that it is permitted to replace Method A.

[0049] When the working fluid is composed of a single compound, the lower flammability limit may be a literature value obtained by the above-mentioned measurement method. When the working fluid is a mixture, the lower flammability limit may be measured by the above-mentioned measurement method, or may be calculated as a weighted average of the flammability limits of the individual compounds constituting the working fluid, based on their molar composition.

[0050] As shown in (D-1), the working fluid of the embodiment of the present invention has a lower flammability limit of 5% by volume or more. Since the working fluid of the embodiment has a lower flammability limit of 5% by volume or more, that is, satisfies the condition (D-1), even if the working fluid leaks from a freezing / refrigeration device or an air-conditioning device, the working fluid does not have high flammability like hydrocarbon refrigerants such as propane, butane, and isobutane in a normal environment, and can be dealt with by taking prescribed measures.

[0051] The lower flammable limit of the working medium of the embodiment is preferably 7% or more, more preferably 10% or more. In particular, it is preferable that the working medium of the embodiment does not have a flammable range. When the working medium of the embodiment has a flammable range, the upper limit is not particularly limited. However, in consideration of the fact that the working medium of the embodiment is not a flammable gas under the High Pressure Gas Safety Act, it is preferable that the lower flammable limit is 10% or more, and the difference between the upper and lower limits of the flammable range is 20% or more.

[0052] (E) Self-degradable The working medium of the embodiment of the present invention does not have autolysis. That is, as shown in (E-1), the pressure of the working medium of the embodiment does not exceed 2.00 MPaG in a combustion test under conditions of 0.98 MPaG and 250°C using equipment conforming to the A method for measuring the flammability range in the High Pressure Gas Safety Act. That is, the working medium has the property of causing substantially no change in temperature and pressure in this combustion test. Since the working fluid of the embodiment satisfies the condition (E-1), it is possible to ensure continuous and stable use, such as ensuring stable operating conditions during long-term operation, in heat cycle systems such as refrigeration and freezing equipment and air conditioning equipment, without taking any special measures.

[0053] Specifically, the evaluation of (E) the autodecomposition property of the working fluid in the present invention is carried out by the following method using an equipment conforming to Method A, which is recommended as an equipment for measuring the flammability range of a gas mixed with a halogen-containing gas in an individual notification under the High Pressure Gas Safety Law.

[0054] The internal volume is 650 cm and the temperature is controlled from the outside at a specified value (250°C). 3 After the specimen (working medium) is sealed in the spherical pressure vessel to a specified pressure (0.98 MPa gauge pressure), approximately 30 J of energy is applied by melting a platinum wire placed inside. The presence or absence of an autodecomposition reaction is confirmed by measuring the temperature and pressure changes that occur inside the pressure vessel after the application.

[0055] If a significant increase in pressure and temperature is observed after the application of the voltage compared to before, it is determined that an autolysis reaction has occurred, i.e., the specimen (working medium) has autolysis properties. Conversely, if no significant increase in pressure and temperature is observed before and after the application of the voltage, it is determined that no autolysis reaction has occurred, i.e., the specimen (working medium) does not have autolysis properties.

[0056] In the present invention, "there is no significant pressure rise to the initial pressure of 0.98 MPaG" means that the pressure after application is in the range of 0.98 MPaG to 2.00 MPa, and "there is no rise to the initial temperature of 250°C" means that the temperature after application is in the range of 250°C to 260°C.

[0057] The characteristics of the working fluid according to the embodiment of the present invention described above are summarized in Table 1 below. In Table 1, the rows represent the physical property items (A) to (E) for evaluating the characteristics, and the columns represent the physical property values ​​(1) to (4). In Table 1, for each of the physical properties (A) to (E), (1) represents an essential requirement, (2) represents a preferred range, (3) represents a more preferred range, and (4) represents a particularly preferred range. In Table 1, the range (less than 300) in column (1) of row (A) (GWP) corresponds to the requirement (A-1) above. Similarly, the range in rows (B) to (E) and column (1) of Table 1 corresponds to (B-1) to (E-1).

[0058] [Table 1]

[0059] The working fluid of the embodiment of the present invention must satisfy the conditions (A)-(1), (B)-(1), (C)-(1), (D)-(1) and (E)-(1) in Table 1. There are no other limitations on the combinations of levels (2) to (4) in each of the items (A) to (E). Most preferred is a working fluid that satisfies all of the conditions (A)-(4), (B)-(4), (C)-(2), (D)-(4) and (E)-(1).

[0060] The heat cycle system to which the working fluid for heat cycle of the present invention is applied may be any heat cycle system using a heat exchanger such as a condenser or an evaporator, without any particular limitations. A heat cycle system, for example, a refrigeration cycle, has a mechanism in which a gaseous working fluid is compressed by a compressor, cooled by a condenser to produce a high-pressure liquid, the pressure is reduced by an expansion valve, and the working fluid is vaporized at a low temperature by an evaporator to remove heat by the heat of vaporization.

[0061] <Working medium composition> The composition of the working fluid for heat cycle of the present invention is not particularly limited as long as it satisfies all the conditions (A-1) to (E-1) above. The working fluid may be composed of a single compound or a mixture. However, no generally known compound is known that satisfies all the conditions (A-1) to (E-1) by itself. Therefore, as a method for obtaining a working fluid of an embodiment that satisfies all the conditions (A-1) to (E-1) above, for example, a method of selecting a combination of compounds constituting the working fluid as follows and adjusting the content of each selected compound so as to satisfy the conditions (A-1) to (E-1) above can be mentioned.

[0062] As a combination of compounds that can constitute the working fluid according to the present invention, in order to satisfy the condition (A-1), a combination of compounds containing at least one HFO (HFC having a carbon-carbon double bond) that has an inherently low GWP and alone satisfies the condition (A-1) is preferred.

[0063] Examples of HFOs include HFO-1123, HFO-1132(Z) which is a cis form of HFO-1132, HFO-1132(E) which is a trans form, 2,3,3,3-tetrafluoropropene (HFO-1234yf), 2-fluoropropene (HFO-1261yf), 1,1,2-trifluoropropene (HFO-1243yc), trans-1,2,3,3,3-pentafluoropropene (HFO-1243yc), and 1,2,3,3,3-pentafluoropropene (HFO-1243yc). 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)), 3,3,3-trifluoropropene (HFO-1243zf), and the like.

[0064] Preferably, from among these HFOs, a compound having high relative cycle performance is selected, for example, a compound that satisfies the condition (B-1) or that can satisfy the condition (B-1) in combination with another compound, such as HFO-1123, HFO-1132(Z), HFO-1132(E), etc.

[0065] The GWP of HFO-1123 is 0.3, measured according to the IPCC Fourth Assessment Report. The GWP of HFO-1132(Z) and HFO-1132(E) is not listed in the IPCC Fourth Assessment Report, but based on the GWP of other HFOs, such as HFO-1234ze(E) and HFO-1234ze(Z) which is 6, and HFO-1234yf which is 4, the GWP can be assumed to be 10 or less.

[0066] Table 2 shows the physical property values ​​(A) to (E) of HFO-1123, HFO-1132(Z) and HFO-1132(E) together with the conditions (A-1) to (E-1) that the working fluid of the embodiment must satisfy. Also shown are the physical property values ​​(A) to (E) of R410A, which the working fluid of the embodiment is intended to replace.

[0067] [Table 2]

[0068] From Table 2, it can be seen that the physical properties of HFO-1123, HFO-1132(Z) and HFO-1132(E) do not reach the values ​​that should be satisfied as the working fluid of the embodiment. Taking these physical property values ​​into consideration, the physical properties already satisfied in HFO-1123, HFO-1132(Z) and HFO-1132(E) are combined with a compound that can compensate for the physical properties that do not reach the values ​​that should be satisfied as the working fluid of the embodiment, while maintaining them so as not to fall outside the range of the working fluid of the embodiment. Examples of such compounds include HFOs and HFCs other than HFO-1123, HFO-1132(Z) and HFO-1132(E).

[0069] As an HFO to be combined with HFO-1123, HFO-1132(Z) and HFO-1132(E), etc., it has a certain level of relative cycle performance and a relative pressure (RDP R410A ) and is not self-decomposing. Specific examples include HFO-1234ze(E), HFO-1234ze(Z), and HFO-1234yf.

[0070] It is preferable that the HFC is appropriately selected as a working fluid in the form of a mixture with the above-mentioned HFO, particularly from the viewpoint of keeping the GWP within the range (A-1) and the relative cycle performance within the range (B-1).

[0071] Examples of HFC include HFC-32, difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane (HFC-125), pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, heptafluorocyclopentane, etc. From the above viewpoints, HFC-32, 1,1-difluoroethane (HFC-152a), 1,1,2,2-tetrafluoroethane (HFC-134), and 1,1,1,2-tetrafluoroethane (HFC-134a) are preferred.

[0072] The HFC to be combined with the above HFO-1123, HFO-1132(Z), HFO-1132(E), etc., has a relatively low GWP, for example, 1500 or less, and has a high relative cycle performance and / or a high relative pressure (RDP R410A ) and is not self-decomposing. Specific examples include HFC-32, HFC-134a, etc., and HFC-32 is particularly preferred.

[0073] Table 3 shows the physical properties (A) to (E) of HFO-1234ze(E), HFO-1234yf, HFC-32 and HFC-134a together with the conditions (A-1) to (E-1) that the working fluid of the embodiment must satisfy. Table 3 also shows the physical properties (A) to (E) of R410A, which the working fluid of the embodiment is intended to replace.

[0074] [Table 3]

[0075] In Tables 2 and 3, 1) for the lower flammability limit is the actual measured value measured according to Method A of the High Pressure Gas Safety Act, and 2) is the literature value measured according to Method A of the High Pressure Gas Safety Act.

[0076] Since HFO-1123, HFO-1132(Z) and HFO-1132(E) are each self-decomposing when used alone, the ratio of HFO-1123, HFO-1132(Z) or HFO-1132(E) to the total amount of the working fluid shall be such that each compound is at least not self-decomposing.

[0077] In the working fluid of the embodiment satisfying (A-1) to (E-1), preferred combinations of compounds when HFO-1123 is used include the following combinations. In the following description, mass % is mass % when the entire working fluid is taken as 100 mass %.

[0078] (i-1) 55 to 62 mass% of HFO-1123 and 38 to 45 mass% of HFO-1234yf (i-2) 10 to 70 mass% of HFO-1123, 10 to 50 mass% of HFO-1234yf, and 10 to 40 mass% of HFC-32 (i-3) 20 to 50 mass% of HFO-1123, 20 to 40 mass% of HFO-1234ze(E), and 10 to 40 mass% of HFC-32

[0079] As long as the conditions (A-1) to (E-1) are satisfied, it is also possible to prepare the working fluid of the present invention by combining HFO-1123, HFO-1234yf, HFO-1234ze(E), and HFC-32 in a predetermined ratio. Furthermore, as long as the conditions (A-1) to (E-1) are satisfied, it is also possible to prepare the working fluid of the present invention by combining HFO-1123 and any HFO other than the combinations of (i-1) to (i-3) above. It is also possible to use a combination of these and HFCs as the working fluid of the present invention.

[0080] In the working fluid of the embodiment satisfying (A-1) to (E-1), preferred combinations of compounds when HFO-1132(Z) is used include the following combinations. In the following description, mass % is mass % when the entire working fluid is taken as 100 mass %.

[0081] (ii-1) 60 to 70 mass% of HFO-1132(Z) and 30 to 40 mass% of HFC-32 (ii-2) 20 to 40 mass% of HFO-1132(Z), 20 to 40 mass% of HFO-1234yf, and 40 to 44 mass% of HFC-32

[0082] As long as the conditions (A-1) to (E-1) are satisfied, the working fluid of the present invention can also be produced by combining HFO-1132(Z) with an HFO or HFC other than the combinations of HFO-1132(Z) and the above (ii-1) and (ii-2).

[0083] In the working fluid of the embodiment satisfying (A-1) to (E-1), preferred combinations of compounds when HFO-1132(E) is used include the following combinations. In the following description, mass % is mass % when the entire working fluid is taken as 100 mass %.

[0084] (iii-1) 60-70% by mass of HFO-1132(E) and 30-40% by mass of HFC-32 amount% (iii-2) 20-70% by mass of HFO-1132(E) and 10% by mass of HFO-1234yf ~40% by mass and 20-40% by mass of HFC-32

[0085] As long as (A-1) to (E-1) are satisfied, HFO-1132(E) may be combined with HFOs or HFCs other than those in the combinations of (iii-1) to (iii-3) above to achieve the operation of the present invention. It can also be used as a medium.

[0086] In addition, as long as (A-1) to (E-1) are satisfied, other HFOs or HFCs may be added to the mixture of the above-listed HFO-1123, HFO-1132(Z), and HFO-1132(E) and other HFOs or HFCs.

[0087] (Other Ingredients) In the working fluid of the embodiment, as long as the conditions (A-1) to (E-1) are satisfied, other components than HFOs and HFCs that are vaporized or liquefied together with HFOs and HFCs may be used together as necessary.

[0088] Examples of such components other than HFOs and HFCs (hereinafter referred to as other components) include carbon dioxide, hydrocarbons, chlorofluoroolefins (CFOs), hydrochlorofluoroolefins (HCFOs), etc. As the other components, components that have little impact on the ozone layer and little impact on global warming are preferable.

[0089] Hydrocarbons include propane, propylene, cyclopropane, butane, isobutane, and pentane. Examples of the hydrocarbon include pentane, isopentane, etc. The hydrocarbon may be used alone or in combination of two or more kinds.

[0090] When the working fluid contains a hydrocarbon, the content is less than 10 mass%, preferably 1 to 5 mass%, and more preferably 3 to 5 mass%, relative to 100 mass% of the working fluid. If the hydrocarbon is equal to or more than the lower limit, the solubility of the mineral refrigeration oil in the working fluid is improved.

[0091] Examples of CFO include chlorofluoropropene and chlorofluoroethylene. As CFO, 1,1-dichloro-2,3,3,3-tetrafluoropropene (CFO-1214ya), 1,3-dichloro-1,2,3,3-tetrafluoropropene (CFO-1214yb), and 1,2-dichloro-1,2-difluoroethylene (CFO-1112) are preferred because they are easy to suppress the flammability of the working medium without significantly reducing the cycle performance of the working medium. One type of CFO may be used alone, or two or more types may be used in combination.

[0092] When the working fluid contains CFO, the content is less than 10 mass%, preferably 1 to 8 mass%, and more preferably 2 to 5 mass%, relative to 100 mass% of the working fluid. When the CFO content is equal to or more than the lower limit, the flammability of the working fluid is easily suppressed. When the CFO content is equal to or less than the upper limit, good cycle performance is easily obtained.

[0093] Examples of HCFO include hydrochlorofluoropropene and hydrochlorofluoroethylene. As HCFO, 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd) and 1-chloro-1,2-difluoroethylene (HCFO-1122) are preferred because they are easy to suppress the flammability of the working fluid without significantly reducing the cycle performance of the working fluid. One type of HCFO may be used alone, or two or more types may be used in combination.

[0094] When the working fluid contains HCFO, the content of HCFO in 100 mass% of the working fluid is less than 10 mass%, preferably 1 to 8 mass%, and more preferably 2 to 5 mass%. When the content of HCFO is equal to or more than the lower limit, the combustibility of the working fluid is easily suppressed. When the content of HCFO is equal to or less than the upper limit, good cycle performance is easily obtained.

[0095] When the working fluid used in the composition for a heat cycle system of the present invention contains other components as described above, the total content of the other components in the working fluid is less than 10 mass%, preferably 8 mass% or less, and more preferably 5 mass% or less, relative to 100 mass% of the working fluid.

[0096] [Composition for heat cycle systems] When the working fluid of the present invention is applied to a heat cycle system, it can be usually mixed with a refrigerating machine oil to be used as the composition for a heat cycle system of the present invention. The composition for a heat cycle system of the present invention containing the working fluid of the present invention and the refrigerating machine oil may further contain known additives such as stabilizers and leak detection substances in addition to these.

[0097] <Refrigerating machine oil> As the refrigerating machine oil, any known refrigerating machine oil that has been used in a heat cycle system composition, together with a working fluid made of halogenated hydrocarbon, can be used without any particular limitation.Specific examples of the refrigerating machine oil include oxygen-containing synthetic oils (ester-based refrigerating machine oils, ether-based refrigerating machine oils, etc.), fluorine-based refrigerating machine oils, mineral-based refrigerating machine oils, and hydrocarbon-based synthetic oils.

[0098] Examples of the ester-based refrigerating machine oil include dibasic acid ester oil, polyol ester oil, complex ester oil, and polyol carbonate ester oil.

[0099] As the dibasic acid ester oil, esters of dibasic acids having 5 to 10 carbon atoms (glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.) and monohydric alcohols having 1 to 15 carbon atoms and linear or branched alkyl groups (methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, etc.) are preferred. Specific examples include ditridecyl glutarate, di(2-ethylhexyl) adipate, diisodecyl adipate, ditridecyl adipate, di(3-ethylhexyl) sebacate, etc.

[0100] Preferred examples of the polyol ester oil include esters of diols (ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 1,5-pentanediol, neopentyl glycol, 1,7-heptanediol, 1,12-dodecanediol, etc.) or polyols having 3 to 20 hydroxyl groups (trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, glycerin, sorbitol, sorbitan, sorbitol-glycerin condensates, etc.) with fatty acids having 6 to 20 carbon atoms (straight-chain or branched fatty acids such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, eicosanoic acid, and oleic acid, or so-called neo acids in which the α carbon atom is quaternary). These polyol ester oils may have a free hydroxyl group.

[0101] As the polyol ester oil, esters of hindered alcohols (neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, etc.) (trimethylolpropane tripelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol tetrapelargonate, etc.) are preferred.

[0102] The complex ester oil is an ester of a fatty acid or dibasic acid with a monohydric alcohol and a polyol. The fatty acid, dibasic acid, monohydric alcohol, and polyol may be the same as those described above.

[0103] The polyol carbonate oil is an ester of carbonic acid and a polyol. The polyol may be the same diol or polyol as described above. The polyol carbonate oil may be a ring-opening polymer of a cyclic alkylene carbonate.

[0104] Examples of ether-based refrigerating machine oils include polyvinyl ether oils and polyoxyalkylene oils.

[0105] Polyvinyl ether oils include those obtained by polymerizing vinyl ether monomers such as alkyl vinyl ethers, and copolymers obtained by copolymerizing vinyl ether monomers with hydrocarbon monomers having an olefinic double bond. The vinyl ether monomer may be used alone or in combination of two or more kinds.

[0106] Examples of the hydrocarbon monomer having an olefinic double bond include ethylene, propylene, various butenes, various pentenes, various hexenes, various heptenes, various octenes, diisobutylene, triisobutylene, styrene, α-methylstyrene, various alkyl-substituted styrenes, etc. The hydrocarbon monomer having an olefinic double bond may be used alone or in combination of two or more.

[0107] The polyvinyl ether copolymer may be either a block copolymer or a random copolymer. The polyvinyl ether oil may be used alone or in combination of two or more kinds.

[0108] Examples of the polyoxyalkylene oil include polyoxyalkylene monools, polyoxyalkylene polyols, alkyl ethers of polyoxyalkylene monools or polyoxyalkylene polyols, and esters of polyoxyalkylene monools or polyoxyalkylene polyols.

[0109] Examples of polyoxyalkylene monools and polyoxyalkylene polyols include those obtained by a method of ring-opening addition polymerization of an alkylene oxide having 2 to 4 carbon atoms (ethylene oxide, propylene oxide, etc.) with an initiator such as water or a hydroxyl group-containing compound in the presence of a catalyst such as an alkali hydroxide. In addition, the oxyalkylene units in the polyalkylene chain may be the same in one molecule, or may contain two or more types of oxyalkylene units. It is preferable that at least an oxypropylene unit is contained in one molecule.

[0110] Examples of initiators used in the reaction include water, monohydric alcohols such as methanol and butanol, and polyhydric alcohols such as ethylene glycol, propylene glycol, pentaerythritol, and glycerol.

[0111] As the polyoxyalkylene oil, an alkyl ether or ester of a polyoxyalkylene monool or a polyoxyalkylene polyol is preferable. As the polyoxyalkylene polyol, a polyoxyalkylene glycol is preferable. In particular, an alkyl ether of a polyoxyalkylene glycol, which is called polyglycol oil and in which the terminal hydroxyl group of the polyoxyalkylene glycol is capped with an alkyl group such as a methyl group, is preferable.

[0112] Examples of fluorine-based refrigeration oils include compounds in which hydrogen atoms of synthetic oils (such as mineral oils, poly-α-olefins, alkylbenzenes, and alkylnaphthalenes described below) are substituted with fluorine atoms, perfluoropolyether oils, and fluorinated silicone oils.

[0113] Examples of mineral refrigeration oils include paraffinic mineral oils and naphthenic mineral oils which are obtained by refining refrigeration oil fractions obtained by atmospheric or reduced pressure distillation of crude oil through an appropriate combination of refining processes (solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, clay treatment, etc.).

[0114] Examples of the hydrocarbon synthetic oil include poly-α-olefins, alkylbenzenes, and alkylnaphthalenes.

[0115] The refrigerating machine oil may be used alone or in combination of two or more kinds. As the refrigeration oil, from the viewpoint of compatibility with the working medium, one or more oils selected from polyol ester oil, polyvinyl ether oil and polyglycol oil are preferable.

[0116] The content of the refrigerating machine oil in the composition for a heat cycle system may be within a range that does not significantly reduce the effects of the present invention, and is preferably 10 to 100 parts by mass, and more preferably 20 to 50 parts by mass, per 100 parts by mass of the working fluid.

[0117] <Other optional ingredients> The stabilizer optionally contained in the composition for a heat cycle system is used to improve the working fluid against heat and oxidation. As the stabilizer, any known stabilizer that has been used in a heat cycle system together with a working fluid made of a halogenated hydrocarbon, such as an oxidation resistance improver, a heat resistance improver, a metal deactivator, etc., can be used without any particular limitation.

[0118] Examples of the oxidation resistance improver and the heat resistance improver include N,N'-diphenylphenylenediamine, p-octyldiphenylamine, p,p'-dioctyldiphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, N-(p-dodecyl)phenyl-2-naphthylamine, di-1-naphthylamine, di-2-naphthylamine, N-alkylphenothiazine, 6-(t-butyl)phenol, 2,6-di-(t-butyl)phenol, 4-methyl-2,6-di-(t-butyl)phenol, 4,4'-methylenebis(2,6-di-t-butylphenol), etc. The oxidation resistance improver and the heat resistance improver may be used alone or in combination of two or more.

[0119] Metal deactivators include imidazole, benzimidazole, 2-mercaptobenzthiazole, 2,5-dimethylcaptothiadiazole, salicylidin-propylenediamine, pyrazole, benzotriazole, tolutriazole, 2-methylbenzamidazole, 3,5-dimethylpyrazole, methylenebis-benzotriazole, organic acids or esters thereof, primary, secondary or tertiary aliphatic amines, amine salts of organic or inorganic acids, heterocyclic nitrogen-containing compounds, amine salts of alkyl acid phosphates or derivatives thereof, and the like.

[0120] The content of the stabilizer in the composition for a heat cycle system may be within a range that does not significantly reduce the effects of the present invention, and is preferably 5 parts by mass or less, and more preferably 1 part by mass or less, per 100 parts by mass of the working fluid.

[0121] Leak detection materials that may optionally be included in the heat cycle system composition include ultraviolet fluorescent dyes, odorous gas or odor masking agents, and the like. Examples of ultraviolet fluorescent dyes include known ultraviolet fluorescent dyes that have conventionally been used in heat cycle systems together with working fluids comprising halogenated hydrocarbons, such as those described in U.S. Pat. No. 4,249,412, JP-A-10-502737, JP-A-2007-511645, JP-A-2008-500437, and JP-A-2008-531836.

[0122] Examples of the odor masking agent include known fragrances that have been used in heat cycle systems together with working fluids made of halogenated hydrocarbons, such as those described in JP-T-2008-500437 and JP-T-2008-531836.

[0123] When a leak detection material is used, a solubilizing agent may be used to improve the solubility of the leak detection material in the working medium.

[0124] Examples of the solubilizing agent include those described in JP-T-2007-511645, JP-T-2008-500437, and JP-T-2008-531836.

[0125] The content of the leak detection substance in the composition for heat cycle systems may be within a range that does not significantly reduce the effects of the present invention, and is preferably 2 parts by mass or less, and more preferably 0.5 parts by mass or less, per 100 parts by mass of working fluid.

[0126] [Heat cycle system] The heat cycle system of the present invention is a system using the composition for a heat cycle system of the present invention. The heat cycle system of the present invention is a heat pump that utilizes the heat obtained in the condenser. The cooling system may be a refrigeration cycle system that utilizes cold energy obtained by an evaporator.

[0127] Specific examples of the heat cycle system of the present invention include refrigeration and freezing equipment, air conditioning equipment, power generation systems, heat transport devices, and secondary cooling machines. Among them, the heat cycle system of the present invention is preferably used as air conditioning equipment that is often installed outdoors, since it can stably and safely exhibit heat cycle performance even in a higher temperature operating environment. The heat cycle system of the present invention is also preferably used as refrigeration and freezing equipment.

[0128] Specific examples of air-conditioning equipment include room air conditioners, packaged air conditioners (packaged air conditioners for stores, packaged air conditioners for buildings, packaged air conditioners for facilities, etc.), gas engine heat pumps, train air conditioners, and automotive air conditioners.

[0129] Specific examples of freezing and refrigeration equipment include showcases (built-in showcases, separate showcases, etc.), commercial freezers and refrigerators, vending machines, ice makers, etc.

[0130] The power generation system is preferably a Rankine cycle power generation system. A specific example of a power generation system is a system in which a working medium is heated in an evaporator using geothermal energy, solar heat, or medium- to high-temperature waste heat of about 50 to 200°C, and the working medium that has become steam in a high-temperature, high-pressure state is adiabatically expanded in an expander, and the work generated by the adiabatic expansion drives a generator to generate power.

[0131] The heat cycle system of the present invention may be a heat transport device, preferably a latent heat transport device.

[0132] Latent heat transport devices include heat pipes and two-phase closed thermosiphon devices that transport latent heat by utilizing the evaporation, boiling, condensation, and other phenomena of the working medium enclosed within the device. Heat pipes are applied to relatively small cooling devices, such as cooling devices for heat generating parts of semiconductor elements and electronic devices. Two-phase closed thermosiphons do not require a wig and have a simple structure, so they are widely used in gas-gas type heat exchangers, for promoting snow melting and preventing freezing on roads, etc.

[0133] During operation of the heat cycle system, it is preferable to provide a means for suppressing the intrusion of moisture or non-condensable gases such as oxygen in order to avoid problems caused by such intrusion.

[0134] When moisture gets into a heat cycle system, problems may occur, especially when the system is used at low temperatures. For example, problems such as freezing in the capillary tube, hydrolysis of the working medium and refrigeration oil, material deterioration due to acid components generated in the cycle, and generation of contaminants may occur. In particular, when the refrigeration oil is polyglycol oil, polyol ester oil, or the like, it is highly hygroscopic and prone to hydrolysis reactions, which deteriorates the properties of the refrigeration oil and is a major cause of impairing the long-term reliability of the compressor. Therefore, in order to suppress the hydrolysis of the refrigeration oil, it is necessary to control the moisture concentration in the heat cycle system.

[0135] As a method for controlling the moisture concentration in the heat cycle system, a method using a moisture removing means such as a desiccant (silica gel, activated alumina, zeolite, etc.) can be mentioned. It is preferable that the desiccant is brought into contact with the liquid composition for the heat cycle system in terms of dehydration efficiency. For example, it is preferable to place the desiccant at the outlet of the condenser 12 or the inlet of the evaporator 14 and bring it into contact with the composition for the heat cycle system.

[0136] Regarding the desiccant, the chemical reactivity between the desiccant and the composition for the heat cycle system, the moisture absorption of the desiccant, etc. From the standpoint of capacity, zeolite-based desiccants are preferred.

[0137] As the zeolite-based desiccant, when using a refrigerating machine oil having a higher moisture absorption amount than conventional mineral-based refrigerating machine oils, a zeolite-based desiccant containing as a main component a compound represented by the following formula (3) is preferred because of its excellent moisture absorption capacity.

[0138] M 2 / n O·Al2O3·xSiO2·yH2O …(3) Here, M is a Group 1 element such as Na or K or a Group 2 element such as Ca, n is the atomic valence of M, and x and y are values ​​determined by the crystal structure. By changing M, the pore size can be adjusted.

[0139] In selecting a desiccant, pore size and crush strength are important. When a desiccant having a pore size larger than the molecular size of the working fluid contained in the heat cycle system composition is used, the working fluid is adsorbed into the desiccant, resulting in a chemical reaction between the working fluid and the desiccant, resulting in undesirable phenomena such as the generation of non-condensable gases, a decrease in the strength of the desiccant, and a decrease in its adsorption capacity.

[0140] Therefore, it is preferable to use a zeolite-based desiccant with a small pore size as the desiccant. In particular, sodium-potassium A-type synthetic zeolite with a pore size of 3.5 angstroms or less is preferable. By applying sodium-potassium A-type synthetic zeolite with a pore size smaller than the molecular size of the working medium, it is possible to selectively adsorb and remove only the moisture in the heat cycle system without adsorbing the working medium. In other words, since the working medium is less likely to be adsorbed onto the desiccant, thermal decomposition is less likely to occur, and as a result, deterioration of the materials constituting the heat cycle system and the generation of contaminants can be suppressed.

[0141] The size of the zeolite desiccant is preferably about 0.5 to 5 mm, since if it is too small it can cause clogging of valves and piping in the heat cycle system, and if it is too large it reduces the drying ability. The shape is preferably granular or cylindrical.

[0142] Zeolite-based desiccants can be formed into any shape by solidifying powdered zeolite with a binder (such as bentonite). As long as the main component is a zeolite-based desiccant, other desiccants (such as silica gel and activated alumina) may be used in combination. The proportion of the zeolite-based desiccant used in the composition for a heat cycle system is not particularly limited.

[0143] Furthermore, if non-condensable gases get into the heat cycle system, they can have a detrimental effect on the heat transfer in the condenser and evaporator and increase the operating pressure, so it is necessary to suppress their mixing as much as possible. In particular, oxygen, which is one of the non-condensable gases, reacts with the working medium and refrigeration oil, promoting their decomposition.

[0144] The non-condensable gas concentration in the gas phase of the working medium is preferably 1.5% by volume or less, particularly preferably 0.5% by volume or less, in terms of volume ratio to the working medium.

[0145] In the heat cycle system of the present invention described above, by using the working fluid of the present invention, it is possible to obtain a cycle performance that is highly safe and practically sufficient while suppressing the influence on global warming, and also to have almost no problems associated with temperature gradient. EXAMPLES

[0146] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. In the following examples and comparative examples, the GWP and the lower flammability limit were calculated using the values ​​of each compound alone according to the above-mentioned method. The values ​​of each compound alone were those shown in Tables 2 and 3 above and Table 4 below.

[0147] [Table 4]

[0148] [Examples 1 to 22] In Examples 1 to 22, working fluids were prepared by mixing HFO-1123 with at least one of HFO-1234yf, HFC-32, and HFO-1234ze(E) in the ratios shown in Tables 5 to 7, and the (A) GWP, (B) relative cycle performance (vs. R410A), (C) relative pressure (RDP) and the like were measured by the above-mentioned method. R410A The results are shown in Tables 5 to 7.

[0149] [Table 5]

[0150] [Table 6]

[0151] [Table 7]

[0152] [Examples 23 to 26] In Examples 23 to 26, working fluids were prepared by mixing HFO-1132(Z) with at least one of HFO-1234yf and HFC-32 in the ratios shown in Tables 8 and 9, and the (A) GWP, (B) relative cycle performance (vs. R410A), (C) relative pressure (RDP) and the like were measured by the above-mentioned method. R410A The results are shown in Tables 8 and 9.

[0153] [Table 8]

[0154] [Table 9]

[0155] [Examples 27 to 34] In Examples 27 to 34, working fluids were prepared by mixing HFO-1132(E) with at least one of HFO-1234yf and HFC-32 in the ratios shown in Tables 10 and 11, and the (A) GWP, (B) relative cycle performance (vs. R410A), (C) relative pressure (RDP) and the like were measured by the above-mentioned method. R410A The results are shown in Tables 10 and 11.

[0156] [Table 10]

[0157] [Table 11]

[0158] [Comparative Examples 1 to 54] In Comparative Examples 1 to 54, working fluids were prepared by mixing at least one HFO with at least one other HFO, HFC, hydrocarbon, and HCFO in the ratios shown in Tables 12 to 20, and the (A) GWP, (B) relative cycle performance (vs. R410A), (C) relative pressure (RDP R410A The results are shown in Tables 12 to 20.

[0159] [Table 12]

[0160] [Table 13]

[0161] [Table 14]

[0162] [Table 15]

[0163] [Table 16]

[0164] [Table 17]

[0165] [Table 18]

[0166] [Table 19]

[0167] [Table 20] [Industrial Applicability]

[0168] The composition for a heat cycle system of the present invention and a heat cycle system using the composition can be used in refrigeration and freezing equipment (built-in showcases, separate showcases, commercial freezers and refrigerators, vending machines, ice makers, etc.), air conditioning equipment (room air conditioners, packaged air conditioners for stores, packaged air conditioners for buildings, packaged air conditioners for facilities, gas engine heat pumps, train air conditioners, automotive air conditioners, etc.), power generation systems (waste heat recovery power generation, etc.), and heat transport devices (heat pipes, etc.). In addition, Japanese Patent Application No. 2014-017031 (filed January 31, 2014), Japanese Patent Application No. 2014-017967 (filed January 31, 2014), Japanese Patent Application No. 2014-030856 (filed February 20, 2014), Japanese Patent Application No. 2014-030857 (filed February 20, 2014), Japanese Patent Application No. 2014-033345 (filed February 24, 2014), Japanese Patent Application No. 2014-053765 (filed March 17, 2014), Japanese Patent Application No. 2014-055603 (filed March 18, 2014), Japanese Patent Application No. 2014-118163 (filed June 6, 2014), Japanese Patent Application No. 2014-118164 (filed June 6, 2014), Japanese Patent Application No. 2014-118165 (filed June 6, 2014), Japanese Patent Application No. 2014-118166 (filed June 6, 2014), Japanese Patent Application No. 2014-118167 (filed June 6, 2014), Japanese Patent Application No. 2014-127744 (filed June 20, 2014), Japanese Patent Application No. 2014-127745 (filed June 20, 2014), Japanese Patent Application No. 2014-148347 (filed July 18, 2014), Japanese Patent Application No. 2014-148348 (filed July 18, 2014), Japanese Patent Application No. 2014-148350 (filed July 18, 2014), Japanese Patent Application No. 2014-187002 (filed September 12, 2014), Japanese Patent Application No. 2014-187003 (filed September 12, 2014), Japanese Patent Application No. 2014-187004 (filed September 12, 2014), Japanese Patent Application No. 2014-187005 (filed on September 12, 2014), and Japanese Patent Application No. 2014-187006 (filed September 12, 2014) The entire contents of the specification, claims, abstract and drawings are hereby incorporated by reference as the disclosure of the present specification. [Explanation of symbols]

[0169] 10... refrigeration cycle system, 11... compressor, 12... condenser, 13... expansion valve, 14... evaporator, 15, 16... pump.

Claims

1. A working medium containing 1,2-difluoroethylene, further comprising 2,3,3,3-tetrafluoropropene; A working fluid for heat cycle having the following characteristics (A-1) to (E-1): (A-1) The global warming potential (100 years) according to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) is less than 300. (B-1) Relative refrigeration capacity (RQ Ｒ４１０Ａ ) and the relative coefficient of performance (RCOP) calculated by the following formula (Y) Ｒ４１０Ａ ) is greater than or equal to 0.

820. [0010] (In formulas (X) and (Y), R410A represents a mixture of difluoromethane and pentafluoroethane in a mass ratio of 1:1, and the specimen represents a working medium to be relatively evaluated. The refrigeration capacities of the specimen and R410A are outputs (kW) when a standard refrigeration cycle is operated under the following temperature condition (T) using the specimen and R410A. The coefficients of performance of the specimen and R410A are values ​​obtained by dividing the outputs (kW) of the specimen and R410A by the power consumption (kW) required for the operation, respectively. [Temperature conditions (T)] The evaporation temperature is 0°C (however, in the case of a non-azeotropic mixture, this is the average temperature of the evaporation start temperature and the evaporation completion temperature), the condensation temperature is 40°C (however, in the case of a non-azeotropic mixture, this is the average temperature of the condensation start temperature and the condensation completion temperature), the degree of supercooling (SC) is 5°C, and the degree of superheat (SH) is 5°C. (C-1) Relative pressure (RDP) calculated by the following formula (Z) Ｒ４１０Ａ ) is less than or equal to 1.

100. [0025] (In formula (Z), R410A represents a mixture of difluoromethane and pentafluoroethane in a mass ratio of 1:1, and the specimen represents a working medium to be relatively evaluated. The compressor discharge gas pressures of the specimen and R410A are compressor discharge gas pressures when a reference refrigeration cycle is operated under the temperature condition (T) using the specimen and R410A. (D-1) The lower limit of the flammable range measured in accordance with Method A of the High Pressure Gas Safety Act is 5% by volume or more. (E-1) In a combustion test under conditions of 0.98 MPaG and 250°C using equipment that complies with Method A for measuring flammability under the High Pressure Gas Safety Act, the pressure does not exceed 2.00 MPaG.

2. 2. The working fluid for heat cycle according to claim 1, wherein the global warming potential is 250 or less.

3. 3. The working fluid for heat cycle according to claim 1, wherein the global warming potential is 200 or less.

4. The working fluid for heat cycle according to any one of claims 1 to 3, wherein the global warming potential is 150 or less.

5. The working fluid for heat cycle according to any one of claims 1 to 4, wherein the 1,2-difluoroethylene comprises trans-1,2-difluoroethylene.

6. The working medium for heat cycle according to claim 5, further comprising at least one selected from the group consisting of difluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane, pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, and heptafluorocyclopentane.

7. The working medium for heat cycle according to claim 5, further comprising at least one selected from the group consisting of difluoromethane, 1,1-difluoroethane, 1,1,2,2-tetrafluoroethane, and 1,1,1,2-tetrafluoroethane.

8. The working medium for heat cycle according to claim 5, further comprising difluoromethane.

9. The working fluid for heat cycle according to any one of claims 6 to 8, wherein a content of the trans-1,2-difluoroethylene is 60 to 70 mass%, and a content of the difluoromethane is 30 to 40 mass%, when the total amount of the trans-1,2-difluoroethylene and the difluoromethane is 100 mass%.

10. The working medium for heat cycle according to claim 5, further comprising at least one selected from the group consisting of trans-1,3,3,3-tetrafluoropropene and cis-1,2,3,3,3-pentafluoropropene.

11. The working fluid for heat cycle according to any one of claims 5 to 10, wherein, when the total amount of the trans-1,2-difluoroethylene and the 2,3,3,3-tetrafluoropropene is taken as 100 mass%, a content of the trans-1,2-difluoroethylene is (20 / 60) x 100 to (70 / 80) x 100 mass%, and a content of the 2,3,3,3-tetrafluoropropene is (10 / 80) x 100 to (40 / 60) x 100 mass%.

12. The working fluid for heat cycle according to any one of claims 6 to 8, wherein, when the whole working fluid is taken as 100 mass%, a content of the trans-1,2-difluoroethylene is 20 to 70 mass%, a content of the 2,3,3,3-tetrafluoropropene is 10 to 40 mass%, and a content of the difluoromethane is 20 to 40 mass%.

13. The working fluid for heat cycle according to any one of claims 6 to 8, wherein the content of the trans-1,2-difluoroethylene is 20 to 70 mass%, the content of the 2,3,3,3-tetrafluoropropene is 10 to 40 mass%, and the content of the difluoromethane is 20 to 40 mass%, when the total amount of the trans-1,2-difluoroethylene, the 2,3,3,3-tetrafluoropropene, and the difluoromethane is 100 mass%. body.

14. The relative coefficient of performance (RCOP Ｒ４１０Ａ ) and relative refrigeration capacity (RQ Ｒ４１０Ａ 14. The working fluid for heat cycle according to claim 1, wherein the product of (a) and (b) is 0.900 or more.

15. The relative coefficient of performance (RCOP Ｒ４１０Ａ ) and relative refrigeration capacity (RQ Ｒ４１０Ａ 15. The working fluid for heat cycle according to claim 14, wherein the product of (a) and (b) is 0.950 or more.

16. The relative pressure (RDP Ｒ４１０Ａ 16. The working fluid for heat cycle according to any one of claims 1 to 15, wherein the value of Mn is 1.000 or less.

17. The working medium for heat cycle according to any one of claims 1 to 16, wherein the working medium has no flammable range.

18. A composition for a heat cycle system, comprising the working fluid for a heat cycle according to any one of claims 1 to 17 and a refrigerating machine oil.

19. A heat cycle system using the composition for a heat cycle system according to claim 18.

20. The heat cycle system according to claim 19, which is a refrigeration / refrigeration device, an air conditioning device, a power generation system, a heat transport device, or a secondary cooling machine.

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