Composition for heat cycle system and heat cycle system

Abstract

To provide a composition for a heat cycle system which comprises a working fluid containing 1,1,2-trifluoroethylene, having cycle performance sufficient as an alternative to R410A while suppressing influence over global warming, and a heat cycle system employing the composition.SOLUTION: A composition for a heat cycle system comprises a working fluid for heat cycle, containing 1,1,2-trifluoroethylene, CF3I and at least one compound selected from a hydrofluorocarbon, a hydrofluoroolefin other than the 1,1,2-trifluoroethylene and a hydrocarbon, and having a temperature glide of at most 7°C, and a heat cycle system employing the composition for a heat cycle system.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Traditionally, chlorofluorocarbons (CFCs) such as chlorotrifluoromethane and dichlorodifluoromethane, and hydrochlorofluorocarbons (HCFCs) such as chlorodifluoromethane have been used as working fluids for heat cycle systems, such 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 secondary cooling fluids. However, CFCs and HCFCs are currently subject to regulation due to their potential 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 refrigerant mixture of HFC-32 and HFC-125 in a 1:1 mass ratio) has been widely used in the past. However, it has been pointed out that HFCs may contribute to global warming.

[0004] Due to its high refrigeration capacity, R410A has been widely used in conventional air conditioning equipment, such as packaged air conditioners and room air conditioners. However, its global warming potential (GWP) is high at 2088, so there is a need to develop a working fluid with a low GWP. In this context, there is a need to develop a working fluid that can simply replace R410A and allow existing equipment to continue to be used as is.

[0005] Recently, expectations have been focused on hydrofluoroolefins (HFOs), i.e., HFCs with carbon-carbon double bonds, which have carbon-carbon double bonds and are easily decomposed by OH radicals in the atmosphere, and therefore have little impact on the ozone layer and little impact on global warming. 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 referred to as saturated hydrofluorocarbons.

[0006] As a working fluid using an 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 or HFOs in order to improve the non-flammability, cycle performance, etc. of the working fluid.

[0007] It is known that HFO-1123 undergoes so-called self-decomposition when an ignition source is present under high temperature or pressure. Therefore, various studies have been conducted on blending a stabilizer that suppresses the self-decomposition of HFO-1123, and working fluids containing CF3I as this stabilizer are also known (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2012 / 157764 [Patent Document 2] International Publication No. 2015 / 125885 [Patent Document 3] Japanese Patent Application Publication No. 2018-104566 Summary of the Invention [Problem to be solved by the invention]

[0009] However, although the combined use of HFO-1123 and CF3I can suppress the self-decomposition of HFO-1123 while making it possible to utilize its high thermal cycle performance, an increase in the CF3I content increases the temperature gradient of the working fluid, causing fluctuations in composition within the thermal cycle system, which can be problematic in practical use.

[0010] Therefore, an object of the present invention is to provide a composition for a heat cycle system containing a working fluid that effectively utilizes the high heat cycle performance of a composition for a heat cycle system containing HFO-1123 and CF3I and that keeps the temperature gradient within a predetermined range, and a heat cycle system using said composition.

[0011] Another object of the present invention is to provide a composition for a heat cycle system containing a working fluid for a heat cycle that has properties such as reducing the impact on global warming, imparting non-flammability, and being able to replace R410A, R407C, and R404A, and a heat cycle system using the composition. [Means for solving the problem]

[0012] The present invention provides a composition for a heat cycle system and a heat cycle system having the configurations described in the following [1] to [9].

[0013] [1] A composition for a heat cycle system, comprising at least one compound selected from 1,1,2-trifluoroethylene, CF3I, and hydrofluorocarbons, hydrofluoroolefins other than 1,1,2-trifluoroethylene, and hydrocarbons, and having a working fluid for a heat cycle with a temperature gradient of 7°C or less. [2] The composition for a heat cycle system according to [1], wherein the hydrofluorocarbon is difluoromethane, pentafluoroethane, 1,1,1,2-tetrafluoroethane or fluoroethane. [3] The composition for a heat cycle system according to [1] or [2], wherein the hydrofluorocarbon is difluoromethane. [4] The composition for a heat cycle system according to [1] or [2], wherein the hydrofluorocarbon is pentafluoroethane. [5] The composition for a heat cycle system according to [1] or [2], wherein the hydrofluorocarbon is 1,1,1,2-tetrafluoroethane. [6] The composition for a heat cycle system according to [1] or [2], wherein the hydrofluorocarbon is fluoroethane. [7] The composition for a heat cycle system according to any one of [1] to [6], wherein the hydrofluoroolefin is 2,3,3,3-tetrafluoropropene, trans-1,3,3,3-tetrafluoropropene, cis-1,3,3,3-tetrafluoropropene, trans-1,2-difluoroethylene or cis-1,2-difluoroethylene. [8] The composition for a heat cycle system according to any one of [1] to [7], wherein the hydrocarbon is propane. [9] The composition for a heat cycle system according to any one of [1] to [8], wherein the content of the hydrofluorocarbon is 10 to 30 mass %.

[10] The composition for a heat cycle system according to any one of [1] to [9], which is non-flammable.

[11] A heat cycle system using the composition for a heat cycle system according to any one of [1] to

[10] .

[12] The heat cycle system according to

[11] , wherein the heat cycle system is a refrigeration / freezing device, an air conditioning device, a power generation system, a heat transport device, or a secondary cooling device. [Effects of the Invention]

[0014] The composition for a heat cycle system of the present invention can provide a composition for a heat cycle system that exhibits the excellent cycle performance of 1,1,2-trifluoroethylene (HFO-1123) while containing a mixed working fluid with a low temperature gradient, and can be used as an alternative to R410A, R407C, and R404A.

[0015] According to the heat cycle system of the present invention, the composition for a heat cycle system of the present invention is applied, and a heat cycle system having both high cycle performance and durability can be obtained. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing a refrigeration cycle system as an example of a heat cycle system of the present invention. [Figure 2] FIG. 2 is a cycle diagram showing the state change of the working fluid for the heat cycle in the refrigeration cycle system of FIG. 1 on a pressure-enthalpy diagram. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, the present invention will be described in detail with reference to embodiments. In this specification, for halogenated hydrocarbons, the abbreviation of 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.

[0018] Furthermore, in this specification, for compounds that exist as geometric isomers, Z and E isomers, depending on the position of a substituent bonded to a carbon atom having a double bond, when the compound name or abbreviation is used without any particular specification, it indicates either the Z or E isomer, or a mixture of Z and E isomers in any ratio. When (Z) or (E) is added after the compound name or abbreviation, it indicates the Z or E isomer of the respective compound.

[0019] [Composition for heat cycle systems] The composition for a heat cycle system of the present embodiment comprises HFO-1123, CF3I, and at least one compound selected from hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs) other than HFO-1123, and hydrocarbons (HCs), and has a working fluid for a heat cycle (hereinafter simply referred to as "working fluid") with a temperature gradient of 7°C or less.

[0020] The composition for a heat cycle system of this embodiment has a working fluid with a reduced temperature gradient, and can be used as a working fluid that can replace, for example, R410A or R407C.

[0021] <Working medium> The composition for a heat cycle system of this embodiment includes a working fluid containing HFO-1123, CF3I, and at least one compound selected from HFCs, HFOs other than HFO-1123, and HCs, as described above.

[0022] The HFO-1123 used in this embodiment is 1,1,2-trifluoroethylene, which is known as a working fluid. This HFO-1123 has high cycle performance for heat cycles, a low GWP, and is a preferred compound as a working fluid considering the global environment. The relative cycle performance (relative coefficient of performance and relative refrigeration capacity) of this HFO-1123 is shown in Table 1. This relative cycle performance is a relative comparison with R410A (a pseudo-azeotropic refrigerant mixture of HFC-32 and HFC-125 in a mass ratio of 1:1). In this specification, the relative coefficient of performance is also referred to as relative COP, and the relative refrigeration capacity is also referred to as relative capacity. The composition for cycle systems of this embodiment is also considered as a replacement for R407C (a mixed composition of HFC-32, HFC-125, and HFC-134a in a mass ratio of 23:25:52) and R134a, and for reference, Table 1 also shows the relative comparison values of R407C and R134a with R410A.

[0023] [Table 1]

[0024] CF3I used in this embodiment acts as a working fluid and can suppress the self-decomposition of HFO-1123. Although the proportions of other components also have an effect, CF3I is a component that can suppress flammability when a composition for a heat cycle system containing a heat cycle working fluid is released into the air.

[0025] The compound used in this embodiment is at least one compound selected from HFCs, HFOs other than HFO-1123, and HCs. These compounds can improve desired properties when used in combination with the above-mentioned HFO-1123 and CF3I. Each of these compounds will be described below.

[0026] (HFC) The HFC used in this embodiment is preferably selected from the above-mentioned viewpoints. That is, the HFC to be combined with HFO-1123 and CF3I is appropriately selected from the viewpoints of improving the cycle performance as the working fluid and keeping the temperature gradient within an appropriate range. Furthermore, it is preferably appropriately selected from the viewpoints of keeping the GWP within an acceptable range and suppressing flammability when used as a composition for a heat cycle system.

[0027] Specifically, HFCs having a carbon number of 1 to 5 are preferred as HFCs that have little impact on the ozone layer and little impact on global warming. HFCs may be linear, branched, or cyclic.

[0028] Examples of HFCs include difluoromethane (HFC-32), fluoroethane (HFC-161), difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane (HFC-125), pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, and heptafluorocyclopentane.

[0029] Among these, as HFCs, HFC-32, HFC-161, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoroethane (HFC-134a), and HFC-125 are preferred, HFC-32, HFC-161, HFC-152a, HFC-134a, and HFC-125 are more preferred, and HFC-32, HFC-134a, and HFC-125 are even more preferred, from the viewpoints of having little impact on the ozone layer and excellent refrigeration cycle characteristics. The HFC may be used alone or in combination of two or more.

[0030] (HFO) It is preferable that HFOs other than HFO-1123 used as optional components are selected from the same viewpoints as the above-mentioned HFCs. Note that HFOs other than HFO-1123 have GWPs that are orders of magnitude lower than HFCs. Therefore, it is preferable that HFOs other than HFO-1123 to be combined with HFO-1123 be appropriately selected, not from a GWP perspective, but with particular attention paid to improving the cycle performance of the working fluid and keeping the temperature gradient and discharge temperature difference within appropriate ranges.

[0031] HFOs other than HFO-1123 include 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,1-difluoroethylene (HFO-1132a), trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)), 2-fluoropropene (HFO-1261yf), 1,1,2-trifluoropropene (HFO-1243yc), and trans-1,2-difluoroethylene (HFO-1132(Z)). Examples include cis-1,2,3,3,3-pentafluoropropene (HFO-1225ye(E)), cis-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z)), trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)), and 3,3,3-trifluoropropene (HFO-1243zf).

[0032] Among these, HFOs other than HFO-1123 are preferably HFO-1132(E), HFO-1132(Z), HFO-1234yf, HFO-1234ze(E), HFO-1234ze(Z), and HFO-1243zf, from the viewpoints of having a high critical temperature and excellent safety and coefficient of performance, with HFO-1132(E), HFO-1132(Z), HFO-1234yf, HFO-1234ze(E), and HFO-1234ze(Z) being more preferred, and HFO-1234yf being even more preferred. One HFO other than HFO-1123 may be used alone, or two or more may be used in combination.

[0033] (HC) Examples of HC include propane, propylene, cyclopropane, butane, isobutane, pentane, isopentane, etc. Among these, propane is preferred as the HC because it is safe, has an excellent coefficient of performance, and can achieve a low GWP. The HC may be used alone or in combination of two or more.

[0034] The working fluid used in this embodiment contains, as essential components, HFO-1123, CF3I, and further compounds to be used in combination with these. The contents of each component in the working fluid will be described below.

[0035] When an HFC is contained, its content can be selected arbitrarily depending on the required properties of the working fluid. In the case of a working fluid containing HFO-1123, CF3I, and HFC-125, a content of HFO-1123 in the range of 40 to 60 mass%, a content of CF3I in the range of 10 to 30 mass%, and a content of HFC-125 in the range of 20 to 30 mass% is preferable because it reduces the temperature gradient and improves the relative coefficient of performance. Furthermore, from the viewpoint of further reducing the temperature gradient, a content of HFO-1123 in the range of 50 to 60 mass%, a content of CF3I in the range of 10 to 20 mass%, and a content of HFC-125 in the range of 20 to 30 mass% is more preferable. HFC-125 is also preferable from the viewpoint of making the resulting working fluid nonflammable.

[0036] In the case of a working fluid containing HFO-1123, CF3I, and HFC-134a, a range of 30 to 60 mass% HFO-1123, 10 to 40 mass% CF3I, and 20 to 40 mass% HFC-134a is preferred to reduce the temperature gradient. Furthermore, from the viewpoint of further increasing capacity, a range of 40 to 60 mass% HFO-1123, 10 to 30 mass% CF3I, and 20 to 40 mass% HFC-134a is more preferred. Furthermore, HFC-134a is preferred from the viewpoint of making the resulting working fluid nonflammable.

[0037] In the case of a working fluid containing HFO-1123, CF3I, and HFC-32, a HFO-1123 content of more than 0 to 60% by mass, a CF3I content of 10 to 60% by mass, and an HFC-32 content of 10 to less than 90% by mass are preferred because they reduce the temperature gradient and improve the relative coefficient of performance. To reduce GWP, a HFO-1123 content of more than 0 to 60% by mass, a CF3I content of more than 10% to less than 50% by mass, and an HFC-32 content of 10% to less than 90% by mass are more preferred. HFC-32 is also preferred from the viewpoint of keeping the GWP of the resulting working fluid low.

[0038] In the case of a working fluid containing HFO-1123, CF3I, and HFC-161, the temperature gradient is reduced preferably when the HFO-1123 content is 30 to 60 mass%, the CF3I content is 20 to 50 mass%, and the HFC-161 content is 10 to 30 mass%. Furthermore, from the viewpoint of further reducing the temperature gradient, the HFO-1123 content is more preferably 30 to 60 mass%, the CF3I content is 20 to 50 mass%, and the HFC-161 content is 20 to 30 mass%.

[0039] Furthermore, when an HFC is contained, multiple types of HFC may be contained. The contents thereof can be arbitrarily selected depending on the required properties of the working fluid. For example, in the case of a working fluid containing HFO-1123, CF3I, HFC-125, and HFC-32, the temperature gradient is reduced and preferred when the HFO-1123 content is 10 to 40 mass%, the CF3I content is 30 to 50 mass%, the HFC-125 content is 10 to 20 mass%, and the HFC-32 content is 10 to 40 mass%. From the viewpoint of improving the relative capacity, the HFO-1123 content is preferably 10 to 40 mass%, the CF3I content is 20 to 40 mass%, and the HFC-125 content is 10 to 20 mass%, and the HFC-32 content is preferably 10 to 40 mass%.

[0040] For example, in the case of a working fluid containing HFO-1123, CF3I, HFC-125, HFC-134a, and HFC-32, the temperature gradient is reduced preferably within the ranges of 10 to 40% by mass of HFO-1123, 10 to 30% by mass of CF3I, 5 to 15% by mass of HFC-125, 10 to 30% by mass of HFC-134a, and 10 to 40% by mass of HFC-32. Furthermore, from the viewpoint of further reducing the temperature gradient, the ranges of 10 to 40% by mass of HFO-1123, more preferably more than 10% to 30% by mass of CF3I, 5 to 15% by mass of HFC-125, 10% to less than 30% by mass of HFC-134a, and 10 to 40% by mass of HFC-32 are more preferred.

[0041] Furthermore, when an HFO other than HFO-1123 is contained, the content thereof can be selected arbitrarily depending on the required properties of the working fluid. For example, in the case of a working fluid containing HFO-1123, CF3I, and HFO-1234yf, it is preferable that the content of HFO-1123 is 10 to 40 mass%, the content of CF3I is 20 to 80 mass%, and the content of HFO-1234yf is 10 to 70 mass%, as this will provide sufficient capacity compared to the relative capacity of 0.45 of the HFO-134a refrigerant (compared to R410A). From the viewpoint of further reducing the temperature gradient, the HFO-1123 content is preferably 10 to 20 mass%, the CF3I content is 20 to 80 mass%, and the HFO-1234yf content is preferably more than 10 and not more than 70 mass%. On the other hand, from the viewpoint of improving the relative capacity, the HFO-1123 content is preferably 20 to 40 mass%, the CF3I content is 20 to 50 mass%, and the HFO-1234yf content is preferably more than 30 and not more than 60 mass%.

[0042] Furthermore, for example, in the case of a working fluid containing HFO-1123, CF3I, and HFO-1234ze(E), it is preferable that the HFO-1123 content be in the range of 10 to 20 mass%, the CF3I content be in the range of 30 to 70 mass%, and the HFO-1234ze(E) content be in the range of 20 to 60 mass%, as this will provide sufficient capacity compared to the relative capacity of the 134a refrigerant (compared to R410A) of 0.45. From the viewpoint of improving the relative capacity, the content of HFO-1123 is preferably in the range of 15 to 20 mass %, the content of CF3I is preferably in the range of 40 to 50 mass %, and the content of HFO-1234ze(E) is preferably in the range of 30 to 40 mass %.

[0043] Furthermore, for example, in the case of a working fluid containing HFO-1123, CF3I, and HFO-1132(E), it is preferable that the HFO-1123 content be in the range of 10 to 90 mass%, the CF3I content be in the range of 10 to 40 mass%, and the HFO-1132(E) content be in the range of 10 to 80 mass%, as this will provide sufficient capacity compared to the relative capacity of 0.45 of the 134a refrigerant (compared to R410A). From the viewpoint of further reducing the temperature gradient, the HFO-1123 content is preferably 10 to 90 mass%, the CF3I content is 10 to 20 mass%, and the HFO-1132(E) content is preferably 10 to 80 mass% or less. On the other hand, from the viewpoint of improving the relative capacity, the HFO-1123 content is preferably 20 to 90 mass%, the CF3I content is 10 to 30 mass%, and the HFO-1132(E) content is preferably 10 to 80 mass% or less. HFO-1123 and HFO-1132(E) are known to undergo an autolytic reaction. From the viewpoint of suppressing the autolytic reaction, the total content of HFO-1123 and HFO-1132(E) is preferably 60 mass% or less.

[0044] Furthermore, for example, in the case of a working fluid containing HFO-1123, CF3I, and HFO-1132(Z), it is preferable that the HFO-1123 content be in the range of 10 to 20 mass%, the CF3I content be in the range of 10 to 60 mass%, and the HFO-1132(Z) content be in the range of 10 to 80 mass%, as this will provide sufficient capacity compared to the relative capacity of the 134a refrigerant (compared to R410A) of 0.45. HFO-1123 and HFO-1132(Z) are known to undergo an autolytic reaction. From the viewpoint of suppressing the autolytic reaction, the total content of HFO-1123 and HFO-1132(Z) is preferably 60 mass% or less.

[0045] Furthermore, for example, in the case of a working fluid containing HFO-1123, CF3I, HFC-32, and HFO-1132(E), it is preferable that the HFO-1123 content be 10 to 80 mass%, the CF3I content be 10 to 40 mass%, the HFC-32 content be 10 to 30 mass%, and the HFO-1132(E) content be 10 to 70 mass%, as this will provide sufficient capacity compared to the relative capacity of 0.45 of the 134a refrigerant (compared to R410A). From the viewpoint of further reducing the temperature gradient, the HFO-1123 content is preferably 10 to 80 mass%, the CF3I content is 10 to 30 mass%, the HFC-32 content is 10 to 30 mass%, and the HFO-1132(E) content is preferably 10 to 70 mass% or less. On the other hand, from the viewpoint of improving the relative capacity, the HFO-1123 content is preferably 10 to 80 mass%, the CF3I content is 10 to 30 mass%, and the HFO-1132(E) content is preferably 10 to 60 mass% or less. HFO-1123 and HFO-1132(E) are known to undergo an autolytic reaction. From the viewpoint of suppressing the autolytic reaction, the total content of HFO-1123 and HFO-1132(E) is preferably 60 mass% or less.

[0046] Furthermore, for example, in the case of a working fluid containing HFO-1123, CF3I, HFO-1234yf, and HFO-1132(E), it is preferable that the HFO-1123 content be in the range of 10 to 80 mass%, the CF3I content be in the range of 10 to 40 mass%, and the HFO-1132(E) content be in the range of 10 to 80 mass%, as this will provide sufficient capacity compared to the relative capacity of the HFO-1123 refrigerant (compared to R410A) of 0.45. From the viewpoint of further reducing the temperature gradient, the HFO-1123 content is preferably 10 to 80 mass%, the CF3I content is 10 to 20 mass%, and the HFO-1132(E) content is preferably 10 to 80 mass%. On the other hand, from the viewpoint of improving the relative capacity, the HFO-1123 content is preferably 10 to 80 mass%, the CF3I content is 10 to 30 mass%, and the HFO-1132(E) content is preferably 10 to 80 mass%. HFO-1123 and HFO-1132(E) are known to undergo an autolytic reaction. From the viewpoint of suppressing the autolytic reaction, the total content of HFO-1123 and HFO-1132(E) is preferably 60 mass% or less.

[0047] Furthermore, for example, in the case of a working fluid containing HFO-1123, CF3I, HFO-1132(E), and HFO-1132(Z), it is preferable that the HFO-1123 content be 10 to 70 mass%, the CF3I content be 10 to 30 mass%, the HFO-1132(E) content be 10 to 70 mass%, and the HFO-1132(Z) content be 10 to 20 mass%, as this will provide sufficient capacity compared to the relative capacity of 0.45 of the HFO-1123 refrigerant (compared to R410A). Furthermore, from the viewpoint of further reducing the temperature gradient, it is preferable that the content of HFO-1123 is 10 to 70 mass%, the content of CF3I is 10 to 20 mass%, the content of HFO-1132(E) is 10 to 70 mass%, and the content of HFO-1132(Z) is 10 to less than 20 mass%. HFO-1123, HFO-1132(E), and HFO-1132(Z) are known to undergo autolysis reactions. From the viewpoint of suppressing the autolysis reactions, the total content of HFO-1123, HFO-1132(E), and HFO-1132(Z) is preferably 60 mass% or less.

[0048] Furthermore, when HC is contained as a compound, its content can be selected arbitrarily depending on the required properties of the working fluid. For example, in the case of a working fluid containing HFO-1123, CF3I, and propane, a content of HFO-1123 in the range of 40 to 60 mass%, a content of CF3I in the range of 10 to 40 mass%, and a content of propane in the range of 15 to 30 mass% is preferable to reduce the temperature gradient. Furthermore, propane is preferable because it can reduce the GWP of the resulting working fluid. Furthermore, from the viewpoint of further reducing the temperature gradient, a content of HFO-1123 in the range of 40 to 60 mass%, a content of CF3I in the range of 10 to 35 mass%, and a content of propane in the range of 20 to 30 mass% is more preferable.

[0049] (Other optional ingredients) The working fluid used in the composition for a heat cycle system of the present embodiment may further contain other optional components such as chlorofluoroolefins (CFOs), hydrochlorofluoroolefins (HCFOs), etc. As the other optional components, components that have little impact on the ozone layer and little impact on global warming are preferred, as long as they do not impair the effects of the present invention.

[0050] Examples of CFOs include chlorofluoropropene, chlorofluoroethylene, etc. Preferred CFOs are 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), since they can easily suppress the flammability of the working fluid without significantly reducing the cycle performance of the working fluid. The CFO may be used alone or in combination of two or more.

[0051] When the working fluid contains CFO, the content thereof is preferably less than 10 mass%, more preferably 1 to 8 mass%, and even more preferably 2 to 5 mass%, relative to 100 mass% of the working fluid. When the CFO content is equal to or greater 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.

[0052] Examples of HCFOs include hydrochlorofluoropropene, hydrochlorofluoroethylene, etc. As HCFOs, 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd) and 1-chloro-1,2-difluoroethylene (HCFO-1122) are preferred because they can easily suppress the flammability of the working fluid without significantly reducing the cycle performance of the working fluid. The HCFO may be used alone or in combination of two or more.

[0053] When the working fluid contains HCFO, the content of HCFO in 100% by mass of the working fluid is preferably less than 10% by mass, more preferably 1 to 8% by mass, and even more preferably 2 to 5% by mass. When the content of HCFO is equal to or greater than the lower limit, the flammability 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.

[0054] When the working fluid used in the composition for a heat cycle system of the present invention contains other optional components as described above, the total content of the other optional components in the working fluid is preferably less than 10 mass%, more preferably 8 mass% or less, and even more preferably 5 mass% or less, relative to 100 mass% of the working fluid.

[0055] <Temperature gradient> The temperature gradient is a measure of the difference in composition between the liquid and vapor phases of a mixture of working fluids. It is defined as the difference in the starting and ending temperatures of a heat exchanger, such as the evaporation temperature in an evaporator or the condensation temperature in a condenser. In an azeotropic mixture, the temperature gradient is zero, and in a near-azeotropic mixture such as R410A, the temperature gradient is very close to zero.

[0056] A large temperature gradient, for example, can cause a decrease in the inlet temperature of the evaporator, increasing the possibility of frost formation, which is a problem. Furthermore, in heat cycle systems, it is common to have the working fluid and heat source fluid such as water or air flowing in a countercurrent manner through the heat exchanger to improve heat exchange efficiency. Since the temperature difference between the heat source fluids is small under stable operating conditions, it is difficult to obtain an energy-efficient heat cycle system using a non-azeotropic mixture of fluids with a large temperature gradient. For this reason, when using a mixture as a working fluid, a working fluid with an appropriate temperature gradient is desired.

[0057] Furthermore, non-azeotropic mixtures have the problem of undergoing compositional changes when they are filled from a pressure vessel into a refrigeration / air-conditioning unit. Furthermore, if a refrigerant leaks from a refrigeration / air-conditioning unit, the refrigerant composition inside the refrigeration / air-conditioning unit is likely to change, making it difficult to restore the refrigerant composition to its initial state. On the other hand, azeotropic or near-azeotropic mixtures can avoid these problems.

[0058] Therefore, the temperature gradient of the composition for a heat cycle system of this embodiment is 7°C or less, more preferably 6°C or less, even more preferably 5°C or less, and particularly preferably 3°C or less.

[0059] <Global Warming Potential (GWP)> In this embodiment, GWP is used as an index for measuring the impact of a working fluid on global warming. In this specification, GWP is the 100-year value from the Fifth Assessment Report (2013) of the Intergovernmental Panel on Climate Change (IPCC), unless otherwise specified. Furthermore, the GWP of a mixture is a weighted average based on the composition mass.

[0060] The global warming potential (100 years) of HFO-1123 contained in the working fluid according to this embodiment is 1, as measured in accordance with the IPCC Fifth Assessment Report.

[0061] Furthermore, R410A (a 1:1 (by mass) composition of HFC-125 and HFC-32) which is intended to be a replacement for the working fluid of this embodiment and has excellent cycle performance has an extremely high GWP of 1924. The two types of HFCs contained in R410A and other representative HFCs, such as HFC-134a, also have high GWPs, as shown in Table 2 below. R407C (a 23:25:52 (by mass) composition of HFC-32, HFC-125, and HFC-134a) which is intended to be a replacement for the working fluid of this embodiment and has excellent cycle performance also has an extremely high GWP of 1624.

[0062] [Table 2]

[0063] As described above, HFO-1123 has an extremely small GWP, and is therefore advantageous in that, for example, when combined with an HFC having high cycle capacity and high GWP to obtain a mixed composition in order to improve cycle performance, etc., HFO-1123 can improve cycle performance while keeping the GWP low compared to other HFOs. This embodiment further contains CF3I, which can stabilize HFO-1123.

[0064] The working fluid used in this embodiment preferably has a GWP of 1000 or less, more preferably 750 or less, even more preferably 675 or less, more preferably 500 or less, still more preferably 300 or less, more preferably 250 or less, and particularly preferably 150 or less.

[0065] <Cycle performance> Here, cycle performance, which is a property required when applying a working fluid to a thermal cycle, can be evaluated by the coefficient of performance (also referred to herein as "COP") and capacity (also referred to herein as "Q"). When the thermal cycle system is a refrigeration cycle system, the capacity is the refrigeration capacity. In addition to the cycle performance, evaluation items when applying a working fluid to a refrigeration cycle system also include temperature gradient, compressor discharge gas temperature, and compressor discharge pressure. Specifically, using a reference refrigeration cycle with the temperature conditions shown below, each item is measured, for example, by the method described below, and evaluated by converting it into a relative value using the value of R410A, which is the target of substitution, excluding the temperature gradient. The evaluation items are explained in detail below.

[0066] (Temperature conditions of the standard refrigeration cycle) Evaporation temperature: 10°C (however, in the case of a non-azeotropic mixture, the average temperature between the evaporation start temperature and the evaporation completion temperature) Condensation completion temperature: 45°C (however, in the case of a non-azeotropic mixture, the average temperature between the condensation start temperature and the condensation completion temperature) Supercooling degree (SC): 10℃ Superheat degree (SH); 10℃ Compressor efficiency: 0.7

[0067] <Relative coefficient of performance> The coefficient of performance is the value obtained by dividing the output (kW) by the power (kW) consumed to obtain that output (kW), and corresponds to energy consumption efficiency. The higher the coefficient of performance, the greater the output can be obtained with less input. The relative coefficient of performance to R410A can be calculated using the following formula (1). In formula (1), the sample represents the working fluid to be evaluated relatively.

[0068]

number

[0069] <Relative refrigeration capacity> The refrigeration capacity is the output of a refrigeration cycle system. The relative refrigeration capacity to R410A can be calculated using the following formula (2). In formula (2), the test substance represents the working fluid to be evaluated.

[0070]

number

[0071] <Compressor discharge pressure difference> From the compressor discharge gas pressure (Px) of the sample, i.e., the working medium to be relatively evaluated, the compressor discharge gas pressure (P R410A ) is subtracted from the pressure (PΔ) to evaluate the value. The compressor discharge gas pressure (hereinafter also referred to as "discharge pressure") in the refrigeration cycle is the maximum pressure in the refrigeration cycle. A lower discharge pressure is preferable because it affects the design pressure of the compressor. In order to replace R410A, the discharge pressure must be a pressure that can be tolerated by the heat cycle system components that were operating with R410A, even if it is lower or higher than the discharge pressure of R410A.

[0072] <Compressor discharge gas temperature difference> From the compressor discharge gas temperature (Tx) of the sample, i.e., the working medium to be evaluated, the compressor discharge gas temperature (T R410A) is subtracted from the temperature (TΔ) to evaluate the temperature. The compressor discharge gas temperature (hereinafter also referred to as "discharge temperature") in the refrigeration cycle is the highest temperature in the refrigeration cycle. A lower discharge temperature is preferable because it affects the heat resistance of the materials constituting the compressor, the refrigerating machine oil that is usually contained in the heat cycle system composition in addition to the working fluid, and the polymeric materials. In order to replace R410A, the discharge temperature must be lower or higher than the discharge temperature of R410A, but must be a temperature that can be tolerated by the heat cycle system components that were operating with R410A.

[0073] The working fluid used in this embodiment is a substitute for R410A, and has a relative refrigeration capacity RQ R410A is preferably 0.70 to 1.50, more preferably 0.90 to 1.50, and particularly preferably 1.00 to 1.50. In the case of replacing R407C, the denominators of the above formulas (1) and (2) may be the coefficient of performance and refrigeration capacity of R407C instead of R410A to evaluate the relative capacity.

[0074] Furthermore, the working fluid used in this embodiment can be used not only as a substitute for R410A, but also as a substitute for R134a, especially when it contains an HFO other than HFO-1123. In this case, the relative refrigeration capacity RQ R410A is preferably 0.45 to 1.50, more preferably 0.50 to 1.50, and particularly preferably 0.55 to 1.50.

[0075] In addition, the relative coefficient of performance (RCOP) R410A is preferably 0.85 to 1.20, more preferably 0.90 to 1.20, and particularly preferably 0.95 to 1.20.

[0076] The discharge pressure difference PΔ is preferably 500 or less, more preferably 100 or less, and particularly preferably 0 or less.

[0077] The discharge temperature difference TΔ is preferably 30° C. or less, more preferably 20° C. or less, and particularly preferably 10° C. or less.

[0078] As a refrigeration cycle system used for evaluating the above characteristics, for example, a refrigeration cycle system whose schematic configuration is shown in Fig. 1 can be used. Below, a method for evaluating the cycle performance, temperature gradient, compressor discharge gas temperature (Tx), and compressor discharge pressure (Px) using the refrigeration cycle system shown in Fig. 1 will be described.

[0079] The refrigeration cycle system 10 shown in Figure 1 is a system roughly composed of 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.

[0080] 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 and high-pressure working medium vapor B (hereinafter referred to as "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 a low-temperature, high-pressure working fluid C. During this process, the fluid F is heated to become a fluid F', which is discharged from the condenser 12 (hereinafter referred to as the "BC process"). (iii) The working medium C discharged from the condenser 12 is expanded by the expansion valve 13 to produce a low-temperature, low-pressure working medium D (hereinafter referred to as "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 high-temperature, low-pressure working medium vapor A. At this time, the load fluid E is cooled to become load fluid E', which is discharged from the evaporator 14 (hereinafter referred to as the "DA process").

[0081] The refrigeration cycle system 10 is a cycle system consisting of adiabatic-isentropic changes, isenthalpic changes, and isobaric changes. When the state change of the working medium is plotted on the pressure-enthalpy curve shown in Figure 2, it can be represented as a trapezoid with vertices A, B, C, and D.

[0082] The AB process is a process in which adiabatic compression is performed in the compressor 11 to convert high-temperature, low-pressure working medium vapor A into high-temperature, high-pressure working medium vapor B, and is shown by line AB in Figure 2. As will be 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. The compressor discharge gas temperature (discharge temperature) is the temperature (Tx) in state B in Figure 2, and is the maximum temperature in the refrigeration cycle. The compressor discharge pressure (discharge pressure) is the pressure (Px) in state B in Figure 2, and is the maximum pressure in the refrigeration cycle. Note that since the BC process is isobaric cooling, the discharge pressure has the same value as the condensation pressure. Therefore, for convenience, the condensation pressure is shown as Px in Figure 2.

[0083] The BC process is a process in which isobaric cooling is performed in the condenser 12 to convert high-temperature, high-pressure working fluid vapor B into low-temperature, high-pressure working fluid C, and is shown by line BC in Figure 2. The pressure at this time is the condensation pressure. Of the intersections of the pressure-enthalpy line and line BC, point T1 on the high-enthalpy side is the condensation temperature, and point T2 on the low-enthalpy side is the condensing boiling point temperature. Here, when the working fluid is a non-azeotropic mixture, the temperature gradient is shown as the difference between T1 and T2.

[0084] 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 shown by the line CD in Figure 2. If the temperature of the low-temperature, high-pressure working medium C is represented by T3, then T2-T3 is the degree of supercooling (SC) of the working medium in the cycles (i) to (iv).

[0085] 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. The intersection T6 on the high-enthalpy side of the pressure-enthalpy line and the DA line is the evaporation temperature. If the temperature of working medium vapor A is shown as T7, then T7 - T6 is the degree of superheat (SH) of the working medium in cycles (i) to (iv). Note that T4 indicates the temperature of working medium D.

[0086] The Q and COP of the working medium are determined by 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 the above, the values can be calculated from the following equations (11) and (12). It is assumed that there is no loss due to equipment efficiency, and no pressure loss in piping or heat exchangers.

[0087] The thermodynamic properties required to calculate the cycle performance of a 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 property values are not available, calculations are performed using an estimation method based on the atomic group contribution method. Q=h A -h D …(11) COP = Q / compression work = (h A -h D ) / (h B -h A ) …(12)

[0088] The above (h A -h D ) corresponds to the output (kW) of the refrigeration cycle, and (h B -h AThe compression work indicated by Q (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 system. In other words, a large Q means that the desired performance can be achieved with a small amount of working fluid, making it possible to miniaturize the system.

[0089] The heat cycle system to which the composition for a heat cycle system of the present embodiment 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 medium 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 liquid is vaporized at a low temperature by an evaporator, and heat is removed by the heat of vaporization.

[0090] The composition for a heat cycle system of the present invention contains, in addition to the working fluid, a refrigerating machine oil, as does a typical composition for a heat cycle system. The composition for a heat cycle system containing a working fluid and a refrigerating machine oil may further contain known additives such as stabilizers and leak detection substances.

[0091] <Nonflammable> The composition for a heat cycle system of this embodiment is preferably non-flammable. Whether the composition is non-flammable or not can be evaluated by subjecting the working fluid containing the composition to the following flammability test. Flammability evaluation can be performed using equipment specified in ASTM E-681. Each working fluid is mixed in a specified ratio to obtain the working fluid to be evaluated, and the resulting working fluid is then mixed with air in a specified ratio. The working fluid is mixed with air in 1% by mass increments between 10 and 90% by mass, and flammability is evaluated when equilibrium is reached.

[0092] A 12-liter flask placed in a thermostatic chamber controlled at 25°C was evacuated, and each working medium mixed with air in the ratios listed above was then charged up to atmospheric pressure. The gas phase near the center of the flask was then ignited by electrical discharge at 15 kV and 30 mA for 0.4 seconds, and the spread of the flame was visually confirmed. An upward flame spread angle of 90° or more was considered flammable, while an angle of less than 90° was considered non-flammable.

[0093] <Refrigerating machine oil> As the refrigerating machine oil, any known refrigerating machine oil conventionally used in compositions for heat cycle systems, including working fluids made of halogenated hydrocarbons, 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.

[0094] Examples of ester-based refrigerating machine oils include dibasic acid ester oils, polyol ester oils, complex ester oils, and polyol carbonate ester oils.

[0095] Preferred dibasic acid ester oils are esters of dibasic acids having 5 to 10 carbon atoms (such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid) with monohydric alcohols having 1 to 15 carbon atoms and a linear or branched alkyl group (such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, and pentadecanol). Specific examples include ditridecyl glutarate, di(2-ethylhexyl) adipate, diisodecyl adipate, ditridecyl adipate, and di(3-ethylhexyl) sebacate.

[0096] Preferred polyol ester oils are 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 (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, etc., or so-called neo acids in which the α-carbon atom is quaternary). These polyol ester oils may have free hydroxyl groups.

[0097] Preferred polyol ester oils are esters of hindered alcohols (neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, etc.) (trimethylolpropane tripelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol tetrapelargonate, etc.).

[0098] The complex ester oil is an ester of a fatty acid or dibasic acid with a monohydric alcohol or polyol. The fatty acid, dibasic acid, monohydric alcohol, and polyol may be the same as those described above.

[0099] 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.

[0100] Examples of ether-based refrigerating machine oils include polyvinyl ether oils and polyoxyalkylene oils.

[0101] 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.

[0102] The vinyl ether monomers may be used alone or in combination of two or more.

[0103] Examples of hydrocarbon monomers 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. One type of hydrocarbon monomer having an olefinic double bond may be used alone, or two or more types may be used in combination.

[0104] 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.

[0105] Examples of polyoxyalkylene oils include polyoxyalkylene monools, polyoxyalkylene polyols, alkyl ethers of polyoxyalkylene monools or polyoxyalkylene polyols, and esters of polyoxyalkylene monools or polyoxyalkylene polyols.

[0106] 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. The oxyalkylene units in the polyalkylene chain may be the same or may contain two or more types of oxyalkylene units in one molecule. It is preferable that at least an oxypropylene unit is contained in one molecule.

[0107] 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.

[0108] The polyoxyalkylene oil is preferably an alkyl ether or ester of a polyoxyalkylene monool or a polyoxyalkylene polyol. The polyoxyalkylene polyol is preferably a polyoxyalkylene glycol. In particular, an alkyl ether of a polyoxyalkylene glycol, called polyglycol oil, in which the terminal hydroxyl groups of the polyoxyalkylene glycol are capped with an alkyl group such as a methyl group, is preferred.

[0109] Examples of fluorine-based refrigeration oils include compounds in which hydrogen atoms of synthetic oils (such as mineral oil, poly-α-olefin, alkylbenzene, and alkylnaphthalene, which will be described later) are substituted with fluorine atoms, perfluoropolyether oils, and fluorinated silicone oils.

[0110] Examples of mineral refrigerating machine oils include paraffinic mineral oils and naphthenic mineral oils, which are obtained by refining refrigerating machine oil fractions obtained by atmospheric or reduced pressure distillation of crude oil through an appropriate combination of refining treatments (solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, clay treatment, etc.).

[0111] Examples of hydrocarbon synthetic oils include poly-α-olefins, alkylbenzenes, and alkylnaphthalenes.

[0112] The refrigerating machine oil may be used alone or in combination of two or more. As the refrigerating machine oil, one or more oils selected from polyol ester oil, polyvinyl ether oil and polyglycol oil are preferred in terms of compatibility with the working medium.

[0113] 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, more preferably 20 to 50 parts by mass, per 100 parts by mass of the working fluid.

[0114] <Other optional ingredients> The stabilizer optionally contained in the composition for a heat cycle system is a component that improves the stability of the working fluid against heat and oxidation. As the stabilizer, any known stabilizer conventionally used in heat cycle systems, including working fluids made of halogenated hydrocarbons, such as oxidation resistance improvers, heat resistance improvers, and metal deactivators, can be used without any particular limitation.

[0115] Examples of oxidation resistance improvers and heat resistance improvers 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. One type of oxidation resistance improver and one type of heat resistance improver may be used alone, or two or more types may be used in combination.

[0116] Examples of 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 their esters, 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.

[0117] 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, more preferably 1 part by mass or less, per 100 parts by mass of the working fluid.

[0118] Optional leak detection materials that may be included in the thermal cycling system composition include ultraviolet fluorescent dyes, odorous gas and odor masking agents, and the like.

[0119] 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.

[0120] Examples of odor masking agents include known fragrances that have been used in heat cycle systems together with working fluids comprising halogenated hydrocarbons, such as those described in JP-A-2008-500437 and JP-A-2008-531836.

[0121] 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.

[0122] Examples of the solubilizing agent include those described in JP-T-2007-511645, JP-T-2008-500437, and JP-T-2008-531836.

[0123] The content of the leak detection substance in the composition for a thermal cycle system 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 the working fluid.

[0124] [Thermal cycle system] The heat cycle system of the present embodiment is a system using the composition for a heat cycle system of the present embodiment. The heat cycle system of the present embodiment may be a heat pump system that uses hot heat obtained in a condenser, or may be a refrigeration cycle system that uses cold heat obtained in an evaporator.

[0125] Specific examples of the thermal cycle system of this embodiment include refrigeration and freezing equipment, air conditioning equipment, power generation systems, heat transport devices, and secondary cooling machines. Among these, the thermal cycle system of the present invention is preferably used as air conditioning equipment, which is often installed outdoors, because it can stably and safely demonstrate thermal cycle performance even in higher temperature operating environments. The thermal cycle system of this embodiment is also preferably used as refrigeration and freezing equipment.

[0126] Specific examples of air conditioning equipment include room air conditioners, package air conditioners (package air conditioners for stores, package air conditioners for buildings, package air conditioners for facilities, etc.), gas engine heat pumps, train air conditioners, and automobile air conditioners.

[0127] Specific examples of freezing and refrigeration equipment include showcases (built-in showcases, separate showcases, etc.), commercial freezers and refrigerators, vending machines, ice makers, etc.

[0128] 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 waste heat in a medium to high temperature range 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 electricity.

[0129] The heat cycle system of this embodiment may be a heat transport device, preferably a latent heat transport device.

[0130] Latent heat transport devices include heat pipes and two-phase closed thermosyphon devices, which transport latent heat by utilizing phenomena such as evaporation, boiling, and condensation of the working medium enclosed within the device. Heat pipes are used in relatively small cooling devices, such as cooling devices for heat-generating parts of semiconductor devices and electronic devices. Two-phase closed thermosyphons do not require a wig and have a simple structure, so they are widely used in gas-gas heat exchangers, to promote snow melting and prevent freezing on roads, etc.

[0131] When operating 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.

[0132] If moisture gets into a heat cycle system, problems can occur, especially when the system is used at low temperatures. For example, problems can occur, such as freezing in the capillary tube, hydrolysis of the working fluid or refrigeration oil, material degradation due to acid components generated in the cycle, and the generation of contaminants. In particular, refrigeration oils such as polyglycol oils and polyol ester oils are highly hygroscopic and prone to hydrolysis, which reduces the properties of the refrigeration oil and is a major cause of damage to the long-term reliability of the compressor. Therefore, to prevent hydrolysis of the refrigeration oil, it is necessary to control the moisture concentration in the heat cycle system.

[0133] One method for controlling the water concentration in a heat cycle system is to use a water removal means such as a desiccant (silica gel, activated alumina, zeolite, etc.). It is preferable to bring the desiccant into contact with the liquid composition for a 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 a heat cycle system.

[0134] As the desiccant, a zeolite-based desiccant is preferred in view of the chemical reactivity between the desiccant and the composition for a heat cycle system and the moisture absorption capacity of the desiccant.

[0135] In the thermal 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 it is also almost free from problems associated with temperature gradients. [Example]

[0136] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0137] [Examples 1-1 to 1-11] In Examples 1-1 to 1-11, working fluids were prepared by mixing HFO-1123 and CF3I in the ratios shown in Table 3. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 3.

[0138] [Table 3]

[0139] The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) of the working fluid containing each compound alone shown in Table 4 below were measured and calculated, and the results are as follows.

[0140] [Table 4]

[0141] [Examples 1-12 to 1-50] In Examples 1-12 to 1-50, working fluids were prepared by mixing HFO-1123, CF3I, and HFO-1132(E) in the proportions shown in Table 5. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 5.

[0142] [Table 5]

[0143] [Examples 1-51 to 1-89] In Examples 1-51 to 1-89, working fluids were prepared by mixing HFO-1123, CF3I, and HFO-1132(Z) in the proportions shown in Table 6. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 6.

[0144] [Table 6]

[0145] [Examples 1-90 to 1-134] In Examples 1-90 to 1-134, working fluids were prepared by mixing HFO-1123, CF3I, and HFO-1132(E) and HFO-1132(Z) in the proportions shown in Table 7. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the methods described above, and the results are also shown in Table 7.

[0146] [Table 7]

[0147] [Examples 2-1 to 2-32] In Examples 2-1 to 2-32, working fluids were prepared by mixing HFO-1123, CF3I, and HFC-125 in the ratios shown in Table 8. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 8.

[0148] [Table 8]

[0149] [Examples 3-1 to 3-27] In Examples 3-1 to 3-27, working fluids were prepared by mixing HFO-1123, CF3I, and HFC-134a in the ratios shown in Table 9. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 9.

[0150] [Table 9]

[0151] [Examples 4-1 to 4-39] In Examples 4-1 to 4-39, working fluids were prepared by mixing HFO-1123, CF3I, and HFC-32 in the ratios shown in Table 10. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 10.

[0152] [Table 10]

[0153] [Examples 4-40 to 4-120] In Examples 4-40 to 4-120, working fluids were prepared by mixing HFO-1123, CF3I, and HFC-32 and HFO-1132(E) in the proportions shown in Tables 11 and 12. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Tables 11 and 12.

[0154] [Table 11]

[0155] [Table 12]

[0156] [Examples 5-1 to 5-34] In Examples 5-1 to 5-34, working fluids were prepared by mixing HFO-1123, CF3I, and HFO-1234yf in the ratios shown in Table 13. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 13.

[0157] [Table 13]

[0158] [Examples 5-35 to 5-140] In Examples 5-35 to 5-140, working fluids were prepared by mixing HFO-1123, CF3I, HFO-1234yf, and HFO-1132(E) in the ratios shown in Tables 14 to 16. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Tables 14 to 16.

[0159] [Table 14]

[0160] [Table 15]

[0161] [Table 16]

[0162] [Examples 6-1 to 6-25] In Examples 6-1 to 6-25, working fluids were prepared by mixing HFO-1123, CF3I, and HFO-1234ze(E) in the proportions shown in Table 17. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the methods described above, and the results are also shown in Table 17.

[0163] [Table 17]

[0164] [Examples 7-1 to 7-49] In Examples 7-1 to 7-49, working fluids were prepared by mixing HFO-1123, CF3I, and propane in the proportions shown in Table 18. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 18.

[0165] [Table 18]

[0166] [Examples 8-1 to 8-49] In Examples 8-1 to 8-49, working fluids were prepared by mixing HFO-1123, CF3I, and HFC-161 in the ratios shown in Table 19. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 19.

[0167] [Table 19]

[0168] [Examples 9-1 to 9-18] In Examples 9-1 to 9-18, working fluids were prepared by mixing HFO-1123, CF3I, HFC-125, and HFC-32 in the ratios shown in Table 20. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 20.

[0169] [Table 20]

[0170] [Examples 10-1 to 10-12] In Examples 10-1 to 10-12, working fluids were prepared by mixing HFO-1123, CF3I, HFC-125, HFC-134a, and HFC-32 in the proportions shown in Table 21. The temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigeration capacity and relative coefficient of performance) were measured and calculated using the above methods, and the results are also shown in Table 21.

[0171] [Table 21]

[0172] [Examples 2-17, 3-21, 4-31, 5-28] The non-flammability of the following working fluids, which were prepared by mixing HFO-1123, CF3I, and HFC-125, HFC-134a, HFC-32, or HFO-1234yf in the proportions shown in Table 22, was measured and calculated using the above method, and the results are also shown in Table 22.

[0173] [Table 22] [Industrial Applicability]

[0174] 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.). The entire contents of the specifications, claims, drawings and abstracts of Japanese Patent Application No. 2018-186916 filed on October 1, 2018 and Japanese Patent Application No. 2018-193586 filed on October 12, 2018 are hereby incorporated by reference as the disclosure of the specification of the present invention. [Explanation of symbols]

[0175] 10... refrigeration cycle system, 11... compressor, 12... condenser, 13... expansion valve, 14... evaporator, 15, 16... pump

Claims

1. 1,1,2-trifluoroethylene, CF ３ I, and fluoroethane, the content of the fluoroethane is 15 to 30 mass% based on the total amount of the working fluid for heat cycle, the working fluid does not contain any optional components, or the content of the optional components is less than 10% by mass based on the total amount of the working fluid for heat cycle; A composition for a heat cycle system, comprising a working fluid for heat cycles having a temperature gradient of 7°C or less.

2. 2. The composition for a heat cycle system according to claim 1, which is non-flammable.

3. A heat cycle system using the composition for a heat cycle system according to claim 1 or 2.

4. 4. The heat cycle system according to claim 3, wherein the heat cycle system is a refrigeration / freezing device, an air conditioning device, a power generation system, a heat transport device, or a secondary cooling device.

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