Working medium for heat cycle and composition for heat cycle system

Abstract

A working medium for heat cycles, which contains trifluoroethylene, 1, 1-difluoroethane, and trifluoroiodomethane, and wherein the ratio of 1, 1-difluoroethane to the total of trifluoroethylene and 1, 1-difluoroethane is 57.5 mass% or less, and the ratio of trifluoroiodomethane to trifluoroethylene, 1, 1-difluoroethane to the total of trifluoroethylene and 1, 1-difluoroethane is 57.5 mass% or less, and the ratio of trifluoroiodomethane to the total of trifluoroethylene and 1, 1-difluoroethane is 57.5 mass% or less. The ratio of the total of trifluoroethylene, 1, 1-difluoroethane and trifluoroiodomethane is 24.5 mass% or less, and the ratio of the total of trifluoroethylene, 1, 1-difluoroethane and trifluoroiodomethane is 75.0 mass% or more relative to the entire working medium for heat cycles.

Description

Technical Field

[0001] The present disclosure relates to a working medium for a heat cycle and a composition for a heat cycle system. Background Art

[0002] In the present disclosure, for a halogenated hydrocarbon, an abbreviation of the compound is added in parentheses after the compound name, and the abbreviation may also be used to replace the compound name as needed.

[0003] Conventionally, as working media for heat cycle systems such as refrigerants for refrigerators, refrigerants for air-conditioning equipment, working media for power generation systems (waste heat recovery power generation, etc.), working media for latent heat transfer devices (heat pipes, etc.), and secondary cooling media, chlorofluorocarbons (CFCs) such as chlorotrifluoromethane and dichlorodifluoromethane, and hydrochlorofluorocarbons (HCFCs) such as chlorodifluoromethane have been used. However, CFCs and HCFCs have been pointed out to have an impact on the ozone layer in the stratosphere and have now become regulated substances.

[0004] For this reason, as working media for heat cycle systems, hydrofluorocarbons (HFCs) such as difluoromethane (HFC-32), tetrafluoroethane, and pentafluoroethane (HFC-125) with little impact on the ozone layer are now used to replace CFCs and HCHCs. For example, R410A (an azeotropic-like mixed refrigerant with a mass ratio of HFC-32 to HFC-125 of 1:1) and the like have been widely used refrigerants. However, HFCs have been pointed out to be a cause of global warming.

[0005] R410A is widely used in so-called commercial air conditioners or air-conditioning equipment such as household air conditioners due to its strong refrigeration capacity. However, the global warming potential (GWP) of R410A is as high as 2256. Therefore, it is necessary to develop a working medium with a low GWP. In this case, it is required to develop a working medium on the premise of only replacing R410A and continuing to use the equipment used so far as it is.

[0006] Patent Document 1 describes a composition that contains fluoroethane (HFC-161), trifluoroethylene (HFO-1123), 1,1-difluoroethane (HFC-152a), and trifluoroiodomethane (CF 3 I) as a working medium to replace R410A. Prior Art Documents Patent Documents

[0007] Patent Document 1: Specification of Chinese Patent Application Publication No. 113969139 Summary of the Invention Technical Problem to be Solved by the Invention

[0008] However, if the composition disclosed in Patent Document 1 is used as the working medium, the pressure loss tends to increase. The pressure loss depends on both the characteristics of the path through which the working medium passes and the physical properties of the working medium itself. Therefore, a working medium with physical properties that do not easily increase the pressure loss is required.

[0009] An object of one aspect of the present disclosure is to provide a working medium for a heat cycle in which an increase in pressure loss is suppressed, and a composition for a heat cycle system made using the same. Technical solutions for solving technical problems

[0010] The present disclosure includes the following aspects. <1> A working medium for a heat cycle, which is a working medium for a heat cycle containing trifluoroethylene, 1,1-difluoroethane, and trifluoroiodomethane, wherein the proportion of 1,1-difluoroethane relative to the total of trifluoroethylene and 1,1-difluoroethane is 57.5% by mass or less, the proportion of trifluoroiodomethane relative to the total of trifluoroethylene, 1,1-difluoroethane, and trifluoroiodomethane is 24.5% by mass or less, the total proportion of trifluoroethylene, 1,1-difluoroethane, and trifluoroiodomethane is 75.0% by mass or more relative to the entire working medium for a heat cycle. <2> The working medium for a heat cycle according to <1>, wherein the proportion of 1,1-difluoroethane relative to the total of trifluoroethylene and 1,1-difluoroethane is 23.0% by mass or less. <3> The working medium for a heat cycle according to <1>, wherein the proportion of 1,1-difluoroethane relative to the total of trifluoroethylene and 1,1-difluoroethane is 11.9% by mass or less. <4> The working medium for a heat cycle according to any one of <1> to <3>, wherein the proportion of trifluoroiodomethane relative to the total of trifluoroethylene, 1,1-difluoroethane, and trifluoroiodomethane is 19.0% by mass or less. <5> The working medium for a heat cycle according to any one of <1> to <4>, wherein the global warming potential of the working medium for a heat cycle is 150 or less. <6> The working medium for a heat cycle according to any one of <1> to <5>, wherein the calorific value of combustion of the working medium for a heat cycle is 15.000 MJ / kg or less. <7> The working medium for a heat cycle according to any one of <1> to <6>, wherein the temperature gradient represented by the difference between the evaporation start temperature and the evaporation completion temperature of the evaporator when the working medium for a heat cycle is applied to a standard refrigeration cycle with an evaporation temperature of 5 °C, a condensation temperature of 40 °C, a subcooling degree (SC) of 5 °C, a superheat degree (SH) of 5 °C, and a compressor efficiency of 0.7 is 7.0 °C or less. <8> A composition for a heat cycle system, which contains the working medium for a heat cycle according to any one of <1> to <7>. Advantages of the Invention

[0011] According to one aspect of the present disclosure, it is possible to provide a working medium for a heat cycle in which an increase in pressure loss is suppressed, and a composition for a heat cycle system made using the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Shown is a schematic structural diagram of a refrigeration cycle system as an example of a heat cycle system according to an embodiment of the present disclosure. Figure 2 Shown is Figure 1 a cycle diagram in which the state change of the working medium for a heat cycle in the refrigeration cycle system is depicted by a pressure-enthalpy diagram. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps, etc.) are not essential unless otherwise specifically stated. The same applies to numerical values and their ranges, which do not limit the present disclosure.

[0014] In the present disclosure, the numerical range represented by "~" includes the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the present disclosure, each component may contain a plurality of corresponding substances. When there are a plurality of substances corresponding to each component in the composition, unless otherwise specifically stated, the proportion of each component refers to the total proportion of the plurality of substances present in the composition.

[0015] In the present disclosure, when describing an embodiment with reference to the drawings, the structure of the embodiment is not limited to the structure shown in the drawings. In addition, the dimensions of the components in each drawing are schematic, and the relative relationship of the dimensions between the components is not limited thereto. In the present disclosure, the combination of two or more preferred aspects is a more preferred aspect.

[0016] In the present disclosure, the GWP of the working medium is the 100-year value of the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). In addition, the GWP of the mixture is based on the weighted average of the composition masses.

[0017] In the present disclosure, the combustion heat of the working medium refers to the value obtained by converting the combustion heat value obtained when 1 mol of the working medium is completely burned with oxygen in a stoichiometric ratio into the combustion heat value per 1 kg of the working medium, and is a theoretical value calculated based on the following assumptions. It is assumed that the compounds in the formation system and the reaction system are gases. The compounds in the formation system, i.e., the combustion products, are HF(g), CO 2 (g), COF 2 (g), and H 2 O(g). In addition, when iodine is part of the molecular structure of the substance, the combustion product I 2 (g) is added. When calculating the combustion heat of the working medium, each compound contained in the working medium is decomposed into the atoms constituting each compound, and a hypothetical substance containing each atom is set considering the molar ratio in the working medium. The combustion heat is calculated using the combustion reaction formula of this hypothetical substance. In addition, C q H r F s in the following formula is equivalent to the hypothetical substance. For example, the combustion reaction formula is defined by the magnitude of the number of H atoms (r) and the number of F atoms (s) in the substance. When the number of H atoms (r) ≥ the number of F atoms (s), the combustion reaction formula uses the following formula.

[0018]

Mathematical formula 1

[0019] When the number of H atoms (r) < the number of F atoms (s), the combustion reaction formula uses the following formula.

[0020]

Mathematical formula 2

[0021] [Working medium for cycle] The working medium for heat cycle according to an embodiment of the present disclosure includes trifluoroethylene (HFO-1123), 1,1-difluoroethane (HFC-152a), and trifluoroiodomethane (CF 3 I). The proportion of HFC-152a relative to the total of HFO-1123 and HFC-152a is 57.5% by mass or less, and the proportion of CF 3 I relative to the total of HFO-1123, HFC-152a, and CF 3 I is 24.5% by mass or less. The total proportion of HFO-1123, HFC-152a, and CF 3 I is 75.0% by mass or more relative to the whole of the working medium for heat cycle.

[0022] Hereinafter, the working medium for the heat cycle will also be simply referred to as the "working medium". In addition, the ratio with respect to the total of HFO-1123 and HFC-152a is also referred to as the "binary component ratio", and the ratio with respect to the total of HFO-1123, HFC-152a and CF 3 I is also referred to as the "ternary component ratio", and the ratio with respect to the entire working medium is also referred to as the "medium ratio". In the working medium of this embodiment, the total of HFO-1123, HFC-152a and CF 3 I is within the above range, and the binary component ratio of HFC-152a and the ternary component ratio of CF 3 I are respectively within the above ranges, so an increase in pressure loss is suppressed. Specifically, by making the total ratio of HFO-1123, HFC-152a and CF 3 I with respect to the medium, the binary component ratio of HFC-152a, and the ternary component ratio of CF 3 I be respectively within the above ranges, it is possible to achieve a relative pressure loss RdP obtained by the method described later R410A of 1.50 or less. If the pressure loss increases, the compression ratio of the compressor becomes larger, so the compressor drive power increases. At the same time, the low-pressure side pressure decreases and the specific gravity of the refrigerant gas on the compressor suction side becomes smaller, so the cooling capacity also decreases. Therefore, in the cycle performance such as COP described later, the actual cycle performance is more likely to decrease than the theoretical cycle performance. In contrast, the decrease in the above actual cycle performance of the working medium with a relative pressure loss RdP R410A of 1.50 or less is suppressed with respect to the theoretical cycle performance.

[0023] The working medium of this embodiment can be used as a substitute for R410A widely used in air conditioning equipment and the like. As described above, although R410A has high cycle performance but high GWP, a working medium with high cycle performance and low GWP is required as its substitute.

[0024] Cycle performance is a necessary performance when using the working medium in a heat cycle system, and is evaluated by the coefficient of performance and the capacity per unit volume. In the case where the heat cycle system is a refrigeration cycle system, the capacity is the refrigeration capacity, which is the output power of the refrigeration cycle system. The coefficient of performance is the value obtained by dividing the output power (kW) by the drive power (kW) consumed to obtain the output power (kW), and is equivalent to the energy consumption efficiency. That is, the coefficient of performance is the capacity per 1 kW of power consumption. The higher the value of the coefficient of performance, the higher the output power can be obtained with a low input power. Hereinafter, the capacity per unit volume is also referred to as "CAP", and the coefficient of performance is also referred to as "COP".

[0025] HFO-1123 has a low GWP, and in terms of cycle performance, although the CAP is high, there is still room for improvement in the COP. As a method for improving the COP while utilizing the low GWP and high CAP of HFO-1123, it is possible to consider mixing HFO-1123 with HFC-152a. HFC-152a is a compound with a relatively low GWP and can achieve a high COP, so an improvement in the COP can be expected. However, HFC-152a is highly flammable compared to HFO-1123.

[0026] Here, for a working medium containing a highly flammable compound, from the perspective of safety, it is required that not only the composition at the time of mixing, i.e., the initial composition, but also the composition after volatilization and leakage due to transportation, etc., i.e., the leakage composition, have low flammability. Therefore, as a working medium that is a mixture of a highly flammable compound and a low-flammability compound, when the most flammable compound in the mixture is designated as compound A, it is preferably to satisfy the following condition 1 or condition 2. Condition 1: Among the compounds contained in the mixture, compound A has the lowest boiling point Condition 2: The mixture contains compound B that is less flammable than compound A and has a lower boiling point than compound A, and compound C that is less flammable than compound A and has a higher boiling point than compound A Since the working medium that satisfies the above condition 1 or condition 2 contains compound C that is less flammable than compound A and has a higher boiling point than compound A, even if volatilization and leakage occur due to transportation, etc., since the boiling points of compound A or compound B are lower than that of compound C, compound C is likely to concentrate, and the concentration of compound A is not likely to occur. Therefore, it is only necessary to consider the flammability of the initial composition, and it is easy to select the composition of the working medium as a mixture.

[0027] In the working medium composed of HFO-1123 and HFC-152a, the boiling point of the most flammable HFC-152a is -24°C, and the boiling point of HFO-1123, which is less flammable than HFC-152a, is -61°C. Therefore, it does not satisfy the above condition 1 and condition 2. Then, in this embodiment, as a compound that is less flammable than HFC-152a and has a higher boiling point than it, CF with a boiling point of -22°C is used 3 I. CF 3 I is a compound with a low GWP, an extremely low ozone depletion potential, and a low heat of combustion. Therefore, the working medium of this embodiment can not only suppress the impact on the ozone layer, but also satisfies the above condition 2, and utilizes the low GWP and high CAP of HFO-1123 and the high COP of HFC-152a to suppress the heat of combustion. And if CF is used 3I, in some cases, the working medium may have physical properties that are prone to an increase in pressure loss depending on its composition. In contrast, for the working medium of the present embodiment, since the total of HFO-1123, HFC-152a, and CF 3 I is within the above-specified range in terms of the proportion to the medium, and the binary-component proportion of HFC-152a and the ternary-component proportion of CF 3 I are respectively within the above-specified ranges, it has physical properties in which an increase in pressure loss is suppressed.

[0028] <Binary-component proportion and ternary-component proportion> As described above, in the working medium of the present embodiment, the binary-component proportion of HFC-152a is 57.5% by mass or less, and the ternary-component proportion of CF 3 I is 24.5% by mass or less. The binary-component proportion of HFC-152a is 57.5% by mass or less as described above. From the viewpoint of reducing the temperature gradient of the evaporator described later, it is preferably 23.0% by mass or less, more preferably 11.9% by mass or less. If the binary-component proportion of HFC-152a is 23.0% by mass or less, it is possible to achieve a temperature gradient of the evaporator obtained by the method described later of 7.0°C or less. In addition, if the binary-component proportion of HFC-152a is 11.9% by mass or less, it is possible to achieve a temperature gradient of the evaporator obtained by the method described later of 5.0°C or less. From the viewpoint of improving the COP of the working medium, the binary-component proportion of HFC-152a is preferably 2.0% by mass or more, more preferably 3.0% by mass or more, and further preferably 5.0% by mass or more.

[0029] CF 3 The ternary-component proportion of I is 24.5% by mass or less as described above. From the viewpoint of suppressing an increase in pressure loss, it is preferably 19.0%, more preferably 15.0%. When the ternary-component proportion of CF 3 I is 24.5% by mass or less, it is possible to achieve a relative pressure loss RdP R410A of 1.50 or less obtained by the method described later. In addition, from the viewpoint of reducing flammability, the ternary-component proportion of CF 3 I is preferably 5% by mass or more, more preferably 10% by mass or more. From the viewpoint of improving the COP of the working medium, the ternary-component proportion of HFC-152a is preferably 1.5% by mass or more, more preferably 4.0% by mass or more, and further preferably 5.0% by mass or more. In addition, from the viewpoint of reducing flammability, the ternary-component proportion of HFC-152a is preferably 54.6% by mass or less, more preferably 50.0% by mass or less, and further preferably 45.0% by mass or less. From the perspective of improving the CAP of the working medium, the proportion of HFO-1123 in the ternary component is preferably 32.1% by mass or more, more preferably 35.0% by mass or more, and further preferably 40.0% by mass or more. In addition, from the perspective of improving the COP of the working medium, the proportion of HFO-1123 in the ternary component is preferably 93.1% by mass or less, more preferably 90.0% by mass or less, and further preferably 85.0% by mass or less.

[0030] <Any component> The working medium of the present disclosure may also optionally contain, as needed, compounds of any component other than HFO-1123, HFC-152a, and CF 3 I that are used as common working media. Among them, the total proportion of HFO-1123, HFC-152a, and CF 3 I in the medium is 75.0% by mass or more, preferably 80.0% by mass or more, more preferably 90.0% by mass or more, and further preferably 95.0% by mass or more. By making the above total proportion in the medium 75.0% by mass or more, when the proportion of HFC-152a in the binary component is 57.5% by mass or less and the proportion of CF 3 I in the ternary component is 24.5% by mass or less, the relative pressure loss RdP described below R410A can reach 1.50 or less. In addition, by making the above total proportion in the medium 75.0% by mass or more, it is possible to suppress the impact on the ozone layer, reduce the GWP, and reduce the combustion heat, and it is easy to simultaneously achieve high CAP and high COP.

[0031] Examples of the above-mentioned optional components include: HFCs other than HFC-152a, HFOs other than HFO-1123 and HFO-1234ze(E), and other components that are vaporized and liquefied together with HFO-1123. Examples of the HFC as an optional component include trifluoroethane, 1,1,2,2-tetrafluoroethane (HFC-134), pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, heptafluorocyclopentane, etc. Examples of the HFO as an optional component include 1,2-difluoroethylene (HFO-1132), 2-fluoropropene (HFO-1261yf), 1,1,2-trifluoropropene (HFO-1243yc), 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 3,3,3-trifluoropropene (HFO-1243zf), etc.

[0032] In addition, as optional components other than the above-mentioned HFCs and HFOs, examples include hydrocarbons such as propylene, cyclopropane, butane, isobutane, pentane, and isopentane; chlorofluoroolfins (CFOs) such as 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); and hydrochlorofluoroolfins (HCFOs) such as 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd) and 1-chloro-1,2-difluoroethylene (HCFO-1122). As optional components, those with little impact on the ozone layer and little impact on global warming are preferred.

[0033] From the viewpoint of reducing the combustion heat of the entire working medium, the working medium of the present disclosure preferably contains substantially no optional components with a monomer combustion heat (HOC) of 16,600 MJ / kg or more. Specifically, the proportion of optional components with a monomer combustion heat of 16,600 MJ / kg or more in the medium is preferably 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.1% by mass or less. Examples of optional components with a monomer combustion heat of 16,600 MJ / kg or more include fluoroethane (HFC-161). From the viewpoint of reducing the GWP of the entire working medium, the working medium of the present disclosure preferably contains substantially no optional components with a monomer GWP greater than 150. Specifically, the proportion of optional components with a monomer GWP greater than 150 in the medium is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 1% by mass or less, particularly preferably 0.5% by mass or less, and most preferably 0.1% by mass or less. Examples of optional components with a monomer GWP greater than 150 include difluoromethane (HFC-32).

[0034] <Proportion in the medium> From the viewpoint of suppressing an increase in pressure loss, the proportion of CF 3 I in the medium is preferably 24.5% by mass or less, more preferably 19.0% by mass or less, and still more preferably 15.0% by mass or less. In addition, from the viewpoint of reducing flammability, the proportion of CF 3 I in the medium is preferably 5% by mass or more, more preferably 10% by mass or more. From the viewpoint of improving the COP of the working medium, the proportion of HFC-152a in the medium is preferably 1.5% by mass or more, more preferably 4.0% by mass or more, and further preferably 5.0% by mass or more. In addition, from the viewpoint of reducing flammability, the proportion of HFC-152a in the medium is preferably 54.6% by mass or less, more preferably 50.0% by mass or less, and further preferably 45.0% by mass or less. From the viewpoint of improving the CAP of the working medium, the proportion of HFO-1123 to the medium is preferably 32.1% by mass or more, more preferably 35.0% by mass or more, and further preferably 40.0% by mass or more. In addition, from the viewpoint of improving the COP of the working medium, the proportion of HFO-1123 to the medium is preferably 93.1% by mass or less, more preferably 90.0% by mass or less, and further preferably 85.0% by mass or less.

[0035] <GWP and HOC of the working medium> From the viewpoint of the small impact of the working medium on global warming, the lower the GWP of the working medium, the more preferable. The GWP of the working medium is preferably 150 or less, more preferably 100 or less, further preferably 50 or less, and particularly preferably 25 or less. The lower the combustion heat of the working medium, the more preferable. The combustion heat (HOC) of the working medium is preferably 15,000 MJ / kg or less, more preferably 13,000 MJ / kg or less, further preferably 11,000 MJ / kg or less, and particularly preferably 10,000 MJ / kg or less.

[0036] <Temperature gradient (TG)> Since the working medium of the present disclosure is a mixture of compounds with a large difference in boiling points, it has a temperature gradient. Here, the above temperature gradient is an index value for evaluating the usability of the mixture working medium, and is defined as the property that the start temperature and the completion temperature of evaporation in an evaporator or condensation in a condenser in a heat exchanger are different, and is also called a "temperature step". The temperature gradient of an azeotropic mixture medium is 0, and the temperature gradient of a near-azeotropic mixture such as R410A is extremely close to 0. If the temperature gradient of the working medium is large, for example, the inlet temperature of the evaporator may decrease, increasing the possibility of frosting. In addition, in a thermal cycle system, in order to improve the heat exchange efficiency, the working medium flowing in the heat exchanger is usually made to form a convection with a heat source fluid such as water and air. Then, in a steady operation state, the temperature difference of the heat source fluid is small. Therefore, when the temperature gradient of the working medium is large, it is difficult to obtain a thermal cycle system with good energy efficiency. Therefore, a working medium with a small temperature gradient is desired.

[0037] The temperature gradient (TG) represented by the difference between the evaporation start temperature and the completion temperature of the evaporator when the working medium is applied to a standard refrigeration cycle with an evaporation temperature of 5 °C, a condensation temperature of 40 °C, a subcooling degree (SC) of 5 °C, a superheat degree (SH) of 5 °C, and a compressor efficiency of 0.7 is preferably 7.0 °C or less, more preferably 6.5 °C or less, further preferably 6.0 °C or less, and particularly preferably 5.0 °C or less. Here, the above evaporation temperature is the average temperature of the evaporation start temperature and the evaporation completion temperature, and the above condensation temperature is the average temperature of the condensation start temperature and the condensation completion temperature. Hereinafter, the temperature gradient represented by the difference between the evaporation start temperature and the completion temperature of the evaporator in the standard refrigeration cycle in which the working medium is applicable to an evaporation temperature of 5°C, a condensation temperature of 40°C, a subcooling degree (SC) of 5°C, a superheat degree (SH) of 5°C, and a compressor efficiency of 0.7 is also referred to as the "temperature gradient of the evaporator".

[0038] In addition, the temperature gradient of the above evaporator is a value calculated from the difference between the evaporation start temperature and the completion temperature of the evaporator, and is a value measured using the standard refrigeration cycle adopting the following temperature conditions in the refrigeration cycle system described later. (Temperature conditions of the standard refrigeration cycle) Evaporation temperature: 5°C (average temperature of the evaporation start temperature and the evaporation completion temperature) Condensation temperature: 40°C (average temperature of the condensation start temperature and the condensation completion temperature) Subcooling degree (SC): 5°C Superheat degree (SH): 5°C Compressor efficiency: 0.7

[0039] The temperature gradient of the working medium in the evaporator varies with the mixing ratio of HFO-1123, HFC-152a, and CF 3 I.

[0040] <CAP and COP of the working medium> The relative refrigerating capacity RCAP of the working medium of the present disclosure with respect to R410A R410A is preferably 0.67 or more, more preferably 0.70 or more, and further preferably 0.75 or more. The relative refrigerating capacity RCAP R410A is the value represented by CAP R410A when the refrigerating capacity of R410A is set as CAP A and the refrigerating capacity of the working medium of the present disclosure is set as CAP A / CAP R410A . In addition, the above refrigerating capacity CAP is the refrigerating capacity per unit volume of the evaporator, and is calculated by the product of the saturated gas density sucked into the compressor and the latent heat of evaporation. Specifically, the refrigerating capacity CAP is a value obtained by using the aforementioned standard refrigeration cycle and the method described later. In addition, the product of the refrigerating capacity per unit volume CAP and the volume flow rate is equivalent to the output power Q (kW) of the cycle system. The present disclosure shows the relative refrigerating capacity with respect to R410A.

[0041] The relative coefficient of performance RCOP of the working medium of the present disclosure with respect to R410A R410APreferably 0.96 or more, more preferably 0.97 or more, and still more preferably 0.98 or more. Relative coefficient of performance RCOP R410A Let the coefficient of performance of R410A be COP R410A and let the coefficient of performance of the working medium of the present disclosure be COP A When using COP A / COP R410A represents the value. In addition, the coefficient of performance COP is the value obtained by dividing the output power Q (kW) by the driving power P (kW) consumed to obtain the output power Q (kW), which is equivalent to the energy consumption efficiency. The higher the value of COP, the higher the output power can be obtained with a lower input power. Specifically, the coefficient of performance COP is the value obtained by using the aforementioned standard refrigeration cycle and the formula considering the compressor efficiency in the following method. The present disclosure shows the relative coefficient of performance with respect to R410A.

[0042] <Pressure loss> The relative pressure loss RdP of the working medium of the present disclosure with respect to R410A R410A is preferably 1.5 or less, more preferably 1.43 or less, and still more preferably 1.4 or less. Let the pressure loss when R410A passes through a certain path be dP R410A and let the pressure loss when the working medium of the present disclosure passes through the same path be dP A When the relative pressure loss RdP R410A is dP A / dP R410A represents the value.

[0043] Here, the pressure loss is a factor that causes a decrease in performance due to an increase in the condensation pressure and a decrease in the evaporation pressure in the refrigeration cycle. The pressure loss ΔP loss is generated by the friction of the fluid flowing inside the pipes in the condenser, evaporator, and connecting pipes in the refrigeration cycle, and is represented by the following formula (13) using the friction coefficient f (-), length L (m), diameter d (m), evaporator capacity Φ 0 (kW), latent heat of evaporation W r (kJ / kg), and specific volume ν s (m 3 / kg). In addition, the above evaporator capacity Φ 0 (kW) is equivalent to the aforementioned output power Q (kW).

[0044]

Mathematical formula 3

[0045] Here, the expression inside the parentheses in the first half of the mathematical formula is determined by the component sizes and performance indicators of the refrigeration cycle. The expression inside the parentheses in the second half is determined by the thermophysical properties of the refrigerant. Therefore, when the equipment indicators and equipment performance are the same, the expression inside the parentheses in the second half needs to be considered. Thus, the pressure loss decreases as the specific volume of the refrigerant decreases and the latent heat of vaporization increases, and increases as the specific volume of the refrigerant increases and the latent heat of vaporization decreases. The smaller the pressure loss, the smaller the work loss, and thus the equipment performance is improved. In addition, in the present disclosure, the expression inside the parentheses in the second half of the pressure loss display formula represents the relative pressure loss RdP with respect to R410A R410A .

[0046] [Composition for Thermal Cycle System] The composition for a thermal cycle system according to an embodiment of the present disclosure includes the aforementioned working medium for a thermal cycle, and may further include other components as needed. When the aforementioned working medium for a thermal cycle is used in a thermal cycle system, for example, the aforementioned working medium for a thermal cycle can be mixed with refrigeration oil and used as the composition for the thermal cycle system of the present embodiment. The composition for the thermal cycle system of the present embodiment including the aforementioned working medium for a thermal cycle and refrigeration oil may further contain known additives such as stabilizers and leak detection substances in addition to these components.

[0047] (Refrigeration Oil) As the refrigeration oil, a known refrigeration oil that can be commonly used with conventional working media composed of halogenated hydrocarbons in a composition for a thermal cycle system can be used without particular limitation. Specifically, as the refrigeration oil, oxygen-containing synthetic oils (such as ester-based refrigeration oils and ether-based refrigeration oils), fluorine-based refrigeration oils, mineral-based refrigeration oils, hydrocarbon-based synthetic oils, etc. can be cited.

[0048] As the ester-based refrigeration oil, dibasic acid ester oils, polyol ester oils, complex ester oils, polyol carbonate oils, etc. can be cited.

[0049] As the dibasic acid ester oil, esters of dibasic acids having 5 or more and 10 or less carbon atoms (such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.) and monohydric alcohols having 1 or more and 15 or less carbon atoms with straight-chain or branched alkyl groups (such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, etc.) are preferred. Specifically, as the dibasic acid ester oil, bis(tridecyl) glutarate, bis(2-ethylhexyl) adipate, diisodecyl adipate, bis(tridecyl) adipate, bis(3-ethylhexyl) sebacate, etc. can be cited.

[0050] As the polyol ester oil, 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 or more and 20 hydroxyl groups (trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, glycerol, sorbitol, sorbitan, sorbitol glycerol condensate, etc.) and fatty acids having 6 or more and 20 carbon atoms (linear or branched fatty acids such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, eicosanoic acid, oleic acid, or so-called neo acids in which the α carbon atom is a quaternary carbon atom, etc.) are preferred. In addition, these polyol ester oils may have free hydroxyl groups.

[0051] As the polyol ester oil, esters of hindered alcohols (such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane and pentaerythritol) (such as trimethylolpropane trispelargonate, pentaerythritol 2-ethylhexanoate and pentaerythritol tetrapelargonate) are preferred.

[0052] The complex ester oil is an ester of a fatty acid, a dibasic acid, a monohydric alcohol, or a polyhydric alcohol. As the fatty acid, the dibasic acid, the monohydric alcohol, and the polyhydric alcohol, the same components as those described above can be used.

[0053] Polyol carbonate oil refers to an ester of carbonic acid and a polyol. As the polyol, the same diols as above or the same polyols as above can be cited. In addition, as the polyol carbonate oil, it can also be a ring-opening polymer of a cyclic alkylene carbonate.

[0054] Examples of the ether-based refrigerating machine oil include polyvinyl ether oil and polyoxyalkylene oil.

[0055] Examples of the polyvinyl ether oil include those obtained by polymerizing a vinyl ether monomer such as alkyl vinyl ether, and copolymers obtained by copolymerizing a vinyl ether monomer and a hydrocarbon monomer having an ethylenic double bond.

[0056] The vinyl ether monomer may be used alone or in combination of two or more.

[0057] Examples of hydrocarbon monomers having olefinic double bonds include ethylene, propylene, various butenes, various pentenes, various hexenes, various heptenes, various octenes, diisobutylene, triisobutylene, styrene, α-methylstyrene, and various alkyl-substituted styrenes. The hydrocarbon monomers having olefinic double bonds may be used alone or in combination of two or more.

[0058] The polyvinyl ether copolymer may be a block copolymer or a random copolymer. The polyvinyl ether oil may be used alone or in combination of two or more.

[0059] Examples of the polyoxyalkylene oil include polyoxyalkylene monohydric alcohols, polyoxyalkylene polyhydric alcohols, alkylethers of polyoxyalkylene monohydric alcohols or polyoxyalkylene polyhydric alcohols, and esters of polyoxyalkylene monohydric alcohols or polyoxyalkylene polyhydric alcohols.

[0060] Examples of the polyoxyalkylene monohydric alcohol or polyoxyalkylene polyhydric alcohol include those obtained by a method such as ring-opening addition polymerization of an alkylene oxide having 2 to 4 carbon atoms (ethylene oxide, propylene oxide, etc.) to an initiator such as water or a hydroxy 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 include two or more types of oxyalkylene units. It is preferred to include at least an oxypropylene unit in one molecule.

[0061] Examples of the initiator used in the reaction include monohydric alcohols such as water, methanol, or butanol, and polyhydric alcohols such as ethylene glycol, propylene glycol, pentaerythritol, and glycerol.

[0062] As the polyoxyalkylene oil, alkylethers or esters of polyoxyalkylene monohydric alcohols or polyoxyalkylene polyhydric alcohols are preferred. In addition, as the polyoxyalkylene polyhydric alcohol, polyalkylene diols are preferred. In particular, alkylethers of polyalkylene diols in which the terminal hydroxyl groups of the polyalkylene diols called polyglycol oils are capped with an alkyl group such as a methyl group are preferred.

[0063] Examples of the fluorine-based refrigeration oil include compounds in which hydrogen atoms of synthetic oils (mineral oils, polyalphaolefins, alkylbenzenes, alkylnaphthalenes, etc., described later) are substituted with fluorine atoms, perfluoropolyether oils, and fluorosilicone oils.

[0064] Examples of the mineral-based refrigeration oil include paraffinic mineral oils and naphthenic mineral oils obtained by purifying the refrigeration oil fraction obtained by atmospheric distillation or vacuum distillation of crude oil through a purification treatment (solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, clay treatment, etc.) in an appropriate combination.

[0065] Examples of the hydrocarbon-based synthetic oil include polyalphaolefins, alkylbenzenes, and alkylnaphthalenes.

[0066] The refrigeration oil can be used alone or in combination of two or more.

[0067] As the refrigeration oil, from the viewpoint of compatibility with the working medium for the heat cycle, one or more selected from polyol ester oils, polyvinyl ether oils, and polyglycol oils are preferred.

[0068] The content of the refrigeration oil in the composition for the heat cycle system may be within a range that does not significantly reduce the effects of the present invention. With respect to 100 parts by mass of the working medium for the heat cycle, it is preferably 10 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass or more and 50 parts by mass or less.

[0069] (Additive) The stabilizer optionally contained in the composition for a thermal cycling system is a component that improves the stability of the working medium for thermal cycling against heat and oxidation. As the stabilizer, known stabilizers that have been commonly used in thermal cycling systems together with conventional working media composed of halogenated hydrocarbons can be used without particular limitation. For example, oxidation resistance enhancers, heat resistance enhancers, metal deactivators, etc.

[0070] Examples of the oxidation resistance enhancer and heat resistance enhancer include N,N'-diphenyl-p-phenylenediamine, 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-(tert-butyl)phenol, 2,6-di-(tert-butyl)phenol, 4-methyl-2,6-di-(tert-butyl)phenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), etc. The oxidation resistance enhancer and heat resistance enhancer can be used alone or in combination of two or more.

[0071] Examples of the metal deactivator include imidazole, benzimidazole, 2-mercaptobenzothiazole, 2,5-dimercapto-1,3,4-thiadiazole, salicylidene-propylenediamine, pyrazole, benzotriazole, tolyltriazole, 2-methylbenzimidazole, 3,5-dimethylpyrazole, methylenebis-benzotriazole, organic acids or their esters, aliphatic primary amines, aliphatic secondary amines or aliphatic tertiary amines, amine salts of organic acids or inorganic acids, heterocyclic nitrogen-containing compounds, amine salts of alkyl acid phosphates or their derivatives, etc.

[0072] The content of the stabilizer in the composition for a thermal cycling system may be within a range that does not significantly reduce the effects of the present invention. Relative to 100 parts by mass of the working medium for thermal cycling, it is preferably 5 parts by mass or less, more preferably 1 part by mass or less.

[0073] Examples of the leakage detection substance optionally contained in the composition for a thermal cycling system include ultraviolet fluorescent dyes, odoriferous gases, and odor masking agents, etc.

[0074] Examples of the ultraviolet fluorescent dye include ultraviolet fluorescent dyes described in U.S. Patent No. 4249412, Japanese Patent Application Laid-Open No. 10-502737, Japanese Patent Application Laid-Open No. 2007-511645, Japanese Patent Application Laid-Open No. 2008-500437, Japanese Patent Application Laid-Open No. 2008-531836, etc., and known ultraviolet fluorescent dyes that have been commonly used in thermal cycling systems together with conventional working media composed of halogenated hydrocarbons.

[0075] Examples of the odor masking agent include substances described in JP-T-2008-500437 and JP-T-2008-531836, and known fragrances that have been conventionally used in combination with a working medium composed of a halogenated hydrocarbon in a thermal cycle system.

[0076] When using a leak detection substance, a solubilizer that enhances the solubility of the leak detection substance in the working medium for the thermal cycle can also be used.

[0077] Examples of the solubilizer include solubilizers described in JP-T-2007-511645, JP-T-2008-500437, and JP-T-2008-531836.

[0078] The content of the leak detection substance in the composition for the thermal cycle system may be within a range that does not significantly reduce the effects of the present invention. Preferably, it is 2 parts by mass or less, more preferably 0.5 parts by mass or less, relative to 100 parts by mass of the working medium for the thermal cycle.

[0079] [Thermal cycle system] The thermal cycle system according to an embodiment of the present disclosure is a system that uses the above-described composition for the thermal cycle system. The thermal cycle system of this embodiment may be a heat pump system that utilizes the warmth obtained from a condenser, or a refrigeration cycle system that utilizes the cold obtained from an evaporator.

[0080] Specific examples of the thermal cycle system of this embodiment include refrigeration and freezing equipment, air conditioning equipment, power generation systems, heat transfer devices, and secondary coolers. Among them, the thermal cycle system of this embodiment can stably and safely exhibit thermal cycle performance even in a higher-temperature working environment, and thus is preferably used as air conditioning equipment that is usually installed outdoors. In addition, the thermal cycle system of this embodiment is preferably used as refrigeration and freezing equipment.

[0081] Specific examples of the air conditioning equipment include household air conditioners (such as indoor air conditioners and central air conditioners), commercial air conditioners (such as shop-use packaged air conditioners, building-use packaged air conditioners, and equipment-use packaged air conditioners), gas engine heat pumps, train air conditioning units, and motor vehicle air conditioning units. The motor vehicle air conditioning unit is preferably an air conditioning device for a fuel vehicle, a hybrid vehicle, an electric vehicle, or a hydrogen energy vehicle, and more preferably an air conditioning device for an electric vehicle.

[0082] Specific examples of the refrigeration and freezing equipment include display cabinets (such as built-in display cabinets and freestanding display cabinets), commercial refrigerators and freezers, vending machines, and ice makers.

[0083] As a power generation system, a power generation system using a Rankine cycle system is preferred. Specifically, as a power generation system, an example is a system in which a working medium heated in an evaporator using geothermal energy, solar heat, waste heat in a medium to high temperature range of about 50°C or more and 200°C or less, etc., to become steam in a high temperature and high pressure state adiabatically expands in an expander, and a generator is driven by the work generated by this adiabatic expansion to generate electricity.

[0084] As a heat transfer device, a latent heat transfer device is preferred. As a latent heat transfer device, examples include a heat pipe and a two-phase closed thermosyphon device that perform latent heat transfer by utilizing phenomena such as evaporation, boiling, and condensation of the working medium enclosed in the device. The heat pipe is suitable for relatively small cooling devices such as cooling devices for heat generating parts of semiconductor elements or electronic devices. Since the two-phase closed thermosyphon device does not require a wick and has a simple structure, it is widely used in gas type heat exchangers, promoting road snow melting, and antifreeze, etc.

[0085] Figure 1 Shown is a schematic structural diagram of a refrigeration cycle system as an example of the heat cycle system of the present embodiment. Hereinafter, using Figure 1 The refrigeration cycle system shown will be used to describe a method for obtaining the refrigeration capacity and coefficient of performance of a specified working medium for a heat cycle.

[0086] As shown in Figure 1 As shown, the refrigeration cycle system 10 has: a compressor 11 that compresses the working medium steam A for the heat cycle into the working medium steam B for the heat cycle at high temperature and high pressure, a condenser 12 that cools and liquefies the working medium steam B discharged from the compressor 11 into the working medium C for the heat cycle at low temperature and high pressure, an expansion valve 13 that expands the working medium C discharged from the condenser 12 into the working medium D for the heat cycle at low temperature and low pressure, an evaporator 14 that heats the working medium D discharged from the expansion valve 13 into the working medium steam A for the heat cycle at high temperature and low pressure, a pump 15 that supplies the load fluid E to the evaporator 14, and a pump 16 that supplies the fluid F to the condenser 12.

[0087] In the refrigeration cycle system 10, the following cycles (i) to (iv) (refrigeration cycle) are repeated.

[0088] (i) The working medium steam A discharged from the evaporator 14 is compressed into the working medium steam B for the heat cycle at high temperature and high pressure in the compressor 11. Hereinafter, it is referred to as the "AB process". (ii) The working medium steam B discharged from the compressor 11 is cooled and liquefied into the working medium C for the heat cycle at low temperature and high pressure in the condenser 12 by the fluid F. At this time, the fluid F is heated into the fluid F' and discharged from the condenser 12. Hereinafter, it is referred to as the "BC process". (iii) The working medium C for the heat cycle discharged from the condenser 12 expands into the low-temperature and low-pressure working medium D for the heat cycle in the expansion valve 13. Hereinafter, it is referred to as the "CD process". (iv) The working medium D for the heat cycle discharged from the expansion valve 13 is heated into the high-temperature and low-pressure working medium vapor A for the heat cycle by the load fluid E in the evaporator 14. At this time, the load fluid E is cooled into the load fluid E' and discharged from the evaporator 14. Hereinafter, it is referred to as the "DA process".

[0089] The refrigeration cycle system 10 is a cycle system composed of adiabatic - isentropic change, isenthalpic change, and isobaric change. Figure 2 Shown is Figure 1 a cycle diagram in which the state change of the working medium for the heat cycle in the refrigeration cycle system 10 is recorded in a pressure - enthalpy diagram. If the state change of the working medium for the heat cycle is recorded on Figure 2 the pressure - enthalpy line (curve) diagram shown, it can be represented as a trapezoid with A, B, C, and D as vertices.

[0090] The AB process is a process in which the high-temperature and low-pressure working medium vapor A is adiabatically compressed into the high-temperature and high-pressure working medium vapor B in the compressor 11, and is represented by the AB line in Figure 2 . As described later, the working medium vapor A is introduced into the compressor 11 in a superheated state, and the obtained working medium vapor B is also a superheated vapor. The density of the gas sucked by the compressor is Figure 2 the density (ρs) in the A state in Figure 2 . The pressure of the gas discharged from the compressor (discharge pressure) is Figure 2 the pressure (Px) in the B state in

[0091] which is the highest pressure in the refrigeration cycle. Among them, since the BC process is an isobaric cooling, the discharge pressure shows the same value as the condensation pressure (Pc). Therefore, in Figure 2 , for convenience, the condensation pressure is represented by Px. 1 is the condensation temperature, and the intersection point T on the low-value side 2 is the condensation boiling point temperature. Here, the temperature gradient of the condenser is represented by the difference between T 1 and T 2 .

[0092] The CD process is a process in which the low-temperature and high-pressure working medium C expands into the low-temperature and low-pressure working medium D in an isenthalpic manner in the expansion valve 13, and is represented by the CD line in Figure 2is represented by the CD line. Among them, if T 3 represents the temperature of the working medium C for the heat cycle at low temperature and high pressure, then T 2 -T 3 is the subcooling degree (SC) of the working medium for the heat cycle in the (i)-(iv) cycles.

[0093] The DA process is a process of isobaric heating in the evaporator 14 to return the working medium D for the heat cycle at low temperature and low pressure to the working medium vapor A for the heat cycle at high temperature and low pressure, which is represented by the DA line in Figure 2 . The pressure at this time is the evaporation pressure (Py). Among the intersections of the pressure-enthalpy line and the DA line, the intersection on the high-enthalpy side is T 6 which is the evaporation temperature. If T 7 represents the temperature of the working medium vapor A for the heat cycle, then T 7 -T 6 is the superheat degree (SH) of the working medium for the heat cycle in the (i)-(iv) cycles. In addition, T 4 represents the temperature of the working medium D for the heat cycle, and T 5 represents the temperature of the working medium D when the subcooling degree (SC) is 0. Here, the temperature gradient of the evaporator is represented by the difference between T 6 and T 4 .

[0094] The CAP and COP of the working medium for the heat cycle are respectively obtained by the following formulas (5)-(8) using the enthalpies hA, hB, hC, and hD in the respective 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) of the working medium for the heat cycle and the refrigerant mass circulation rate qmr. Among them, the pressure losses of the pipes and heat exchangers are not taken into account. In addition, in the following formulas (5)-(8), the loss work of the compressor described later is not taken into account, and the compressor efficiency is not considered.

[0095] The cycle performance (CAP and COP) of the working medium for the heat cycle was obtained by performing theoretical calculations of the refrigeration cycle of the working medium under the above conditions using the National Institute of Science and Technology (NIST) Reference Fluid Thermodynamic and Transport Properties Database (REFPROP 10.0). In addition, regarding the physical property data of HFO-1123, the values described in Thermodynamic properties of trifluoroethene (R1123): (p, ρ, T) behavior and fundamental equation of state by Akasaka, R., Higashi, Y., Sakoda, N., Fukuda, S. and Lemmon, E. W., International Journal of Refrigeration, 2020, 119, 457-467 were used.

[0096] CAP = (hA - hD) × ρs... Equation (5) COP = Q / P = (qmr × (hA - hD)) / (qmr × (hB - hA)) = (hA - hD) / (hB - hA)... Equation (6) Q = qmr × (hA - hD)... (7) P = qmr × (hB - hA)... (8) In the above equations (5) to (8), ρs represents the density of the gas inhaled by the compressor (kg / m 3 ), Q represents the output power (kW), and P represents the driving power (kW).

[0097] In addition, when the loss work of the compressor is applied to the working medium in the form of heat, if the compressor efficiency is set to η, the enthalpy hB' in the state of the working medium vapor B' (after compression, high temperature and high pressure) after the AB process is expressed by the following equation (9) using hA, hB, and η. hB' = hA + (hB - hA) / η... (9) Furthermore, when considering the compressor efficiency, COP and P are expressed by the following equations (10) and (11). COP = Q / P = (hA - hD) / (hB' - hA)... (10) P = qmr × (hB' - hA)... (11) In the above formula (10), Q represents the output power (kW), and P represents the driving power (kW).

[0098] In addition, when the thermal cycle system is in operation, in order to avoid problems caused by the mixing of moisture, non-condensable gases such as oxygen, etc., it is preferable to provide means for suppressing the mixing of these substances.

[0099] If moisture mixes into the thermal cycle system, problems sometimes occur especially during low-temperature use. For example, problems such as ice formation in the capillary, hydrolysis of the working medium or refrigerant oil for the thermal cycle, deterioration of materials due to acid components generated during the cycle, and generation of contaminants may occur. Especially when the refrigerant oil is polyglycol oil, polyol ester oil, etc., its hygroscopicity is extremely high, and hydrolysis reactions are likely to occur, reducing its characteristics as a refrigerant oil, which will become a major cause of damaging the long-term reliability of the compressor. Therefore, in order to suppress the hydrolysis of the refrigerant oil, it is necessary to control the moisture concentration in the thermal cycle system.

[0100] As a method for controlling the moisture concentration in the thermal cycle system, methods such as using water removal means such as desiccants (silica gel, activated alumina, zeolite, etc.) can be cited. From the perspective of dehydration efficiency, it is preferable to bring the desiccant into contact with the liquid composition for the thermal cycle system. For example, it is advisable to arrange a desiccant at the outlet of the condenser 12 or the inlet of the evaporator 14 to bring it into contact with the composition for the thermal cycle system.

[0101] As the desiccant, from the perspectives of the chemical reactivity between the desiccant and the composition for the thermal cycle system and the moisture absorption capacity of the desiccant, zeolite desiccants are preferred.

[0102] As the zeolite desiccant, in the case of using a refrigerant oil with a higher moisture absorption amount compared to conventional mineral refrigerant oils, from the perspective of excellent moisture absorption capacity, a zeolite desiccant mainly composed of a compound represented by the following formula (12) is preferred.

[0103] M 2 / n O·Al 2 O 3 ·xSiO 2 ·yH 2 O…Formula (12)

[0104] Among them, M is a Group 1 element such as Na, K, etc. or a Group 2 element such as Ca, etc., n is the valence of M, and x and y are values determined by the crystal structure. The pore diameter can be adjusted by changing M.

[0105] When selecting a desiccant, the pore diameter and crush strength are important. When using a desiccant with a pore diameter larger than the molecular diameter of the working medium for heat cycle in the heat cycle system composition, the working medium for heat cycle will be adsorbed in the desiccant. As a result, the working medium for heat cycle reacts chemically with the desiccant to generate non-condensable gases, and undesirable phenomena such as a decrease in the strength of the desiccant and a decline in the adsorption capacity occur.

[0106] Therefore, as the desiccant, it is preferable to use zeolite desiccants with a small pore diameter. In particular, sodium-potassium A-type synthetic zeolite with a pore diameter of 3.5 Å or less is preferred. By using sodium-potassium A-type synthetic zeolite with a pore diameter smaller than the molecular diameter of the working medium for heat cycle, it is possible to selectively adsorb and remove only the moisture in the heat cycle system without adsorbing the working medium for heat cycle. In other words, the working medium for heat cycle is not easily adsorbed on the desiccant, so thermal decomposition is not likely to occur. As a result, the deterioration and contamination of the materials constituting the heat cycle system can be suppressed.

[0107] If the size of the zeolite desiccant is too small, it will cause blockage of the valves and fine parts of the piping in the heat cycle system. If it is too large, the drying capacity will decrease. Therefore, it is preferably about 0.5 mm or more and 5 mm or less. As the shape of the zeolite desiccant, granular or cylindrical shapes are preferred.

[0108] The zeolite desiccant can be formed into any shape by curing powdered zeolite with an adhesive (such as bentonite). If the zeolite desiccant is the main component, other desiccants (such as silica gel, activated alumina, etc.) can also be used in combination. The usage ratio of the zeolite desiccant relative to the heat cycle system composition is not particularly limited.

[0109] Furthermore, if non-condensable gases are mixed into the heat cycle system, it will cause negative effects such as poor heat conduction in the condenser and evaporator and an increase in the working pressure. Therefore, it is necessary to strongly suppress their mixing. In particular, oxygen, which is one of the non-condensable gases, reacts with the working medium for heat cycle and refrigeration oil to promote decomposition.

[0110] In the gas phase part of the working medium for heat cycle, the concentration of non-condensable gases is preferably 1.5 vol% or less, particularly preferably 0.5 vol% or less, based on the volume ratio relative to the working medium for heat cycle.

[0111] The heat cycle system of one embodiment of the present disclosure described above uses the working medium for heat cycle of the present disclosure, has excellent durability, can suppress the impact on global warming, and obtains sufficient practical cycle performance. Examples

[0112] Hereinafter, the embodiments of the present disclosure will be described in detail by way of examples, but the embodiments of the present disclosure are not limited thereto.

[0113] Figure 1 In the refrigeration cycle system 10, when the working medium having the composition shown in Table 1 below is applied, the temperature gradient of the evaporator (TG (°C) in the table), the relative coefficient of performance RCOP with respect to R410A R410A (RCOP in the table R410A ), the relative refrigerating capacity RCAP with respect to R410A R410A (RCAP in the table R410A ), the relative pressure loss with respect to R410A (RdP in the table R410A ), the heat of combustion (HOC (MJ / kg) in the table), and the GWP are obtained by the aforementioned method. The results are shown in Table 1. In addition, "1123 (mass%)" in the table represents the proportion of HFO-1123 in the medium, "152a (mass%)" represents the proportion of HFC-152a in the medium, "CF 3 I (mass%)" represents the proportion of CF 3 I in the medium, and "152a to binary component (mass%)" represents the proportion of HFC-152a to the binary component.

[0114] [Table 1]

[0115] In the above examples, Examples 1 to 16 are examples, Examples 17 to 20 are comparative examples, and Examples 21 to 23 are reference examples. As shown in Table 1, the relative pressure loss is reduced in Examples 1 to 16 compared with Examples 17 to 20 and 23. In addition, the relative coefficient of performance RCOP R410A is higher in Examples 1 to 16 than in Example 21, the relative refrigerating capacity RCAP R410A is higher and the heat of combustion HOC and the GWP are lower in Examples 1 to 16 than in Example 22. Industrial applicability

[0116] The working medium for a heat cycle and the heat cycle system using the composition for a heat cycle system of the present disclosure can be used in refrigeration and freezing equipment (built-in display cabinets, stand-alone display cabinets, commercial refrigeration and freezing warehouses, vending machines, ice makers, etc.), air conditioning equipment (room air conditioners, shop combined air conditioners, building combined air conditioners, equipment combined air conditioners, gas engine heat pumps, train air conditioning units, motor vehicle air conditioning units, etc.), power generation systems (waste heat recovery power generation, etc.), heat transfer devices (heat pipes, etc.), and secondary coolers.

[0117] The entire disclosure of Japanese Application No. 2022-172710, filed on October 27, 2022, is incorporated herein by reference. In addition, all documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each such document, patent application, and technical standard were specifically and individually set forth. Symbol Explanation

[0118] 10 Refrigeration cycle system 11 Compressor 12 Condenser 13 Expansion valve 14 Evaporator 15, 16 Pumps.

Claims

1. A working medium for thermal cycle, which is a working medium for thermal cycle containing trifluoroethylene, 1,1-difluoroethane and trifluoroiodomethane, wherein, the proportion of 1,1-difluoroethane relative to the total of trifluoroethylene and 1,1-difluoroethane is 57.5% by mass or less, the proportion of trifluoroiodomethane relative to the total of trifluoroethylene, 1,1-difluoroethane and trifluoroiodomethane is 24.5% by mass or less, the total proportion of trifluoroethylene, 1,1-difluoroethane and trifluoroiodomethane is 75.0% by mass or more relative to the whole of the working medium for thermal cycle.

2. The working medium for thermal cycle according to claim 1, wherein, the proportion of 1,1-difluoroethane relative to the total of trifluoroethylene and 1,1-difluoroethane is 23.0% by mass or less.

3. The working medium for thermal cycle according to claim 1, wherein, the proportion of 1,1-difluoroethane relative to the total of trifluoroethylene and 1,1-difluoroethane is 11.9% by mass or less.

4. The working medium for thermal cycle according to claim 1, wherein, the proportion of trifluoroiodomethane relative to the total of trifluoroethylene, 1,1-difluoroethane and trifluoroiodomethane is 19.0% by mass or less.

5. The working medium for thermal cycle according to claim 1, wherein, the global warming potential value of the working medium for thermal cycle is 150 or less.

6. The working medium for thermal cycle according to claim 1, wherein, the combustion heat of the working medium for thermal cycle is 15.000 MJ / kg or less.

7. The working medium for thermal cycle according to claim 1, wherein, when the working medium for thermal cycle is applied to a standard refrigeration cycle with an evaporation temperature of 5°C, a condensation temperature of 40°C, a subcooling degree (SC) of 5°C, a superheat degree (SH) of 5°C, and a compressor efficiency of 0.7, the temperature gradient represented by the difference between the evaporation start temperature and the completion temperature of the evaporator is 7.0°C or less.

8. A composition for a thermal cycle system, which contains the working medium for thermal cycle according to any one of claims 1 to 7.

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