Composition for a thermal cycling system and thermal cycling system

Abstract

The present invention provides a composition for a thermal cycle system containing HFO-1123 and HFO-1234yf, which contains a working medium with cycle performance that can replace R410A while suppressing the impact on the greenhouse effect, and a thermal cycle system using the composition. A composition for a thermal cycle system containing a working medium for thermal cycle with a greenhouse effect coefficient (100 years) lower than 675 in the 4th report of the Intergovernmental Panel on Climate Change (IPCC), which contains trifluoroethylene and 2,3,3,3-tetrafluoropropene, and a thermal cycle system using the composition for a thermal cycle system.

Description

[0001] This application is a divisional application of a Chinese patent application titled "Composition for Thermal Circulation System and Thermal Circulation System" with national application number 201580009642.0, which is the entry into the Chinese national phase of a PCT international application with international application number PCT / JP2015 / 051410 and international filing date of January 20, 2015. Technical Field

[0002] The present invention relates to a composition for a thermal circulation system and a thermal circulation system using the composition. Background Art

[0003] In this specification, for halogenated hydrocarbons, the abbreviation of the compound is noted in parentheses after the compound name, but in this specification, the abbreviation may sometimes be used instead of the compound name as needed.

[0004] Conventionally, as working media for thermal circulation systems such as refrigerants for refrigerators, refrigerants for air conditioners, 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 trichlorofluoromethane 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 are currently restricted.

[0005] For this reason, as working media for thermal circulation systems, hydrofluorocarbons (HFCs) such as difluoromethane (HFC-32), tetrafluoroethane, and pentafluoroethane (HFC-125), which have less impact on the ozone layer, are used instead of CFCs and HCFCs. For example, R410A (an approximate azeotropic refrigerant mixture with a mass ratio of HFC-32 and HFC-125 of 1:1) and the like are refrigerants widely used today. However, HFCs have been pointed out to possibly cause the greenhouse effect.

[0006] R410A is widely used in ordinary air conditioning machines such as so-called central air conditioners and room air conditioners due to its high refrigerating capacity. However, its global warming potential (GWP) is as high as 2088, so the development of working media with low GWP is required. At this time, the development of working media on the premise of only replacing R410A and being able to directly continue using the machines used so far is required.

[0007] Recently, since hydrofluoroolefins (HFOs), which are HFCs having a carbon-carbon double bond, have a carbon-carbon double bond and this bond is easily decomposed by OH radicals in the atmosphere, they are expected as working media with less impact on the ozone layer and less impact on the greenhouse effect. In this specification, saturated HFCs are referred to as HFCs without special explanation, and are used separately from HFOs. In addition, HFCs may sometimes be clearly denoted as saturated hydrofluorocarbons.

[0008] As a working medium using HFO, for example, Patent Document 1 discloses a technique related to a working medium using trifluoroethylene (HFO-1123) that can obtain excellent cycle performance while having the above characteristics. In Patent Document 1, for the purpose of improving the non-flammability, cycle performance, etc. of the working medium, attempts have also been made to combine various HFCs or HFOs with HFO-1123 to form a working medium.

[0009] However, in Patent Document 1, there is no disclosure or suggestion of combining HFO-1123 with HFC or other HFOs to form a working medium from the perspective of comprehensively balancing capacity, efficiency, and temperature gradient to obtain a practical working medium as an alternative candidate for R410A.

[0010] Prior art documents

[0011] Patent documents

[0012] Patent Document 1: International Publication No. 2012 / 157764 Summary of the invention

[0013] Technical problems to be solved by the invention

[0014] An object of the present invention is to provide a composition for a thermal cycle system containing HFO-1123, which includes a working medium having cycle performance that can replace R410A while suppressing the impact on the greenhouse effect, and a thermal cycle system using the composition.

[0015] Technical solutions for solving the technical problems

[0016] The present invention provides a composition for a thermal cycle system and a thermal cycle system having the configurations described in the following [1] to

[15] .

[0017] [1] A composition for a thermal cycle system, characterized in that it contains a working medium for thermal cycling whose greenhouse effect coefficient (100 years) in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) is less than 675 and includes HFO-1123.

[0018] [2] The composition for a thermal cycle system according to [1], characterized in that the relative efficiency coefficient (RCOP R410A ) of the above-mentioned working medium for thermal cycling is 0.85 to 1.20.

[0019] [Equation 1]

[0020]

[0021] (In Formula (1), R410A represents a mixture with a mass ratio of HFC-32 to HFC-125 of 1:1, and the sample represents the working medium to be relatively evaluated. The efficiency coefficients of the sample and R410A are obtained by dividing the output power (kW) obtained when they are respectively used in a reference refrigeration cycle with an evaporation temperature of -15°C (in the case of azeotropic mixture, it refers to the average temperature of the evaporation start temperature and the evaporation end temperature), a condensation temperature of 30°C (in the case of azeotropic mixture, it refers to the average temperature of the condensation start temperature and the condensation end temperature), a subcooling degree (SC) of 5°C, and a superheat degree (SH) of 0°C by the required power consumption (kW).)

[0022] [3] The composition for a thermal cycle system according to [1] or [2], characterized in that the relative refrigerating capacity (RQ R410A ) calculated by the following formula (2) of the working medium for the thermal cycle is 0.70 to 1.50.

[0023] [Formula 2]

[0024]

[0025] (In Formula (2), R410A represents a mixture with a mass ratio of HFC-32 to HFC-125 of 1:1, and the sample represents the working medium to be relatively evaluated. The refrigerating capacity of the sample and R410A is the output power (kW) obtained when they are respectively used in a reference refrigeration cycle with an evaporation temperature of -15°C (wherein, in the case of azeotropic mixture, it refers to the average temperature of the evaporation start temperature and the evaporation end temperature), a condensation temperature of 30°C (wherein, in the case of azeotropic mixture, it refers to the average temperature of the condensation start temperature and the condensation end temperature), a subcooling degree (SC) of 5°C, and a superheat degree (SH) of 0°C.)

[0026] [4] The composition for a thermal cycle system according to any one of [1] to [3], characterized in that the temperature gradient represented by the difference between the evaporation start temperature and the evaporation end temperature in the evaporator when the working medium for the thermal cycle is used in a reference refrigeration cycle with an evaporation temperature of -15°C (wherein, in the case of azeotropic mixture, it refers to the average temperature of the evaporation start temperature and the evaporation end temperature), a condensation temperature of 30°C (wherein, in the case of azeotropic mixture, it refers to the average temperature of the condensation start temperature and the condensation end temperature), a subcooling degree (SC) of 5°C, and a superheat degree (SH) of 0°C is 8°C or less.

[0027] [5] The composition for a heat cycle system according to any one of [1] to [4], characterized in that for the working medium for the heat cycle, the evaporation temperature is -15 °C (wherein, in the case of azeotropic mixture, it refers to the average temperature of the evaporation start temperature and the evaporation end temperature), the condensation temperature is 30 °C (wherein, in the case of azeotropic mixture, it refers to the average temperature of the condensation start temperature and the condensation end temperature), the subcooling degree (SC) is 5 °C, and the superheat degree (SH) is 0 °C. The value (TΔ) obtained by subtracting the compressor discharge gas temperature (T R410A ) when a mixture with a mass ratio of HFC-32 and HFC-125 of 1:1 is used for the above-mentioned reference refrigeration cycle from the compressor discharge gas temperature (Tx) of the reference refrigeration cycle is 30 °C or less.

[0028] [6] The composition for a heat cycle system according to any one of [1] to [5], characterized in that the combustion heat of the working medium for the heat cycle is less than 19 MJ / kg.

[0029] [7] The composition for a heat cycle system according to any one of [1] to [6], characterized in that the working medium for the heat cycle contains HFO-1123, saturated hydrofluorocarbons, and HFO-1234ze.

[0030] [8] The composition for a heat cycle system according to [7], characterized in that the saturated hydrofluorocarbon is HFC-32, HFC-152a, HFC-134a, or HFC-125.

[0031] [9] The composition for a heat cycle system according to [7], characterized in that the saturated hydrofluorocarbon is HFC-32.

[0032]

[10] The composition for a heat cycle system according to [9], characterized in that in the working medium for the heat cycle, the proportion of HFO-1123 is 10 to 80% by mass, the proportion of HFC-32 is 10 to 80% by mass, and the proportion of HFO-1234ze is 5 to 45% by mass.

[0033]

[11] The composition for a heat cycle system according to any one of [1] to

[10] , characterized in that the proportion of HFO-1123 in the working medium for the heat cycle is 20% by mass or more.

[0034]

[12] The composition for a heat cycle system according to any one of [1] to

[11] , characterized in that the proportion of HFO-1123 in the working medium for the heat cycle is 20 to 80% by mass.

[0035]

[13] The composition for a thermal cycle system according to any one of [1] to

[12] , characterized in that the proportion of HFO-1123 in the working medium for the thermal cycle is 40 to 60% by mass.

[0036]

[14] A thermal cycle system, characterized in that the composition for a thermal cycle system according to any one of [1] to

[13] is used.

[0037]

[15] The thermal cycle system according to

[14] , characterized in that the thermal cycle system is a refrigeration / refrigeration machine, an air-conditioning machine, a power generation system, a heat transfer device or a secondary cooler.

[0038] Effects of the Invention

[0039] If the present invention is adopted, a composition for a thermal cycle system containing a working medium for a thermal cycle having a cyclic performance capable of substituting for R410A while suppressing the influence on the greenhouse effect can be provided in the composition for a thermal cycle system containing HFO-1123.

[0040] The thermal cycle system of the present invention is a thermal cycle system that uses a composition for a thermal cycle system capable of substituting for R410A and having little influence on the greenhouse effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic structural diagram showing an example of a reference refrigeration cycle system for evaluating the thermal cycle system of the present invention.

[0042] Figure 2 It is to Figure 1 The cycle diagram in which the state change of the working medium in the refrigeration cycle system is recorded on the pressure-enthalpy diagram. DETAILED DESCRIPTION OF THE INVENTION

[0043] Hereinafter, embodiments of the present invention will be described.

[0044] [Composition for Thermal Cycle System]

[0045] The composition for a thermal cycle system of the present invention contains a working medium for a thermal cycle (hereinafter, simply referred to as "working medium") including HFO-1123 and having a greenhouse effect coefficient (100 years) lower than 675 in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC).

[0046] In the composition for a thermal cycle system of the present invention, as a working medium capable of substituting for R410A while suppressing the influence on the greenhouse effect, a working medium containing HFO-1123 is used.

[0047] (A) Greenhouse Effect Coefficient (GWP)

[0048] In the present invention, GWP is used as an index of the impact on the greenhouse effect of the metering working medium. In this specification, GWP is the 100-year value of the Fourth Assessment Report (2007) of the Intergovernmental Panel on Climate Change (IPCC) unless otherwise specified. In addition, the GW in the mixture is the weighted average of the constituent masses.

[0049] The greenhouse effect coefficient (100-year) of HFO-1123 contained in the working medium of the present invention is a value measured based on the Fourth Assessment Report of the IPCC and is 0.3. This value is significantly smaller than the GWP of other HFOs, such as 6 for HFO-1234ze(E) and 4 for HFO-1234yf, etc.

[0050] In addition, the GWP of R410A (a 1:1 (by mass) composition of HFC-125 and HFC-32) with excellent cycle performance to be replaced by the working medium of the present invention is extremely high, being 2088. The two types of HFCs contained in R410A and other representative HFCs, such as HFC-134a, also have high GWP as shown in Table 1 below.

[0051] [Table 1]

[0052] Compound GWP R410A 2088 HFO-1123 0.3 HFO-1234yf 4 HFO-1234ze(E) 6 HFC-32 675 HFC-134a 1430 HFC-125 3500

[0053] Here, as properties necessary when using a certain working medium in a heat cycle, the cycle performance can be evaluated by the coefficient of efficiency (referred to as "COP" in this specification) and the capacity (referred to as "Q" in this specification). In the case where the heat cycle system is a refrigeration cycle system, the capacity is the refrigeration capacity. As evaluation items when using the working medium in a refrigeration cycle system, in addition to the above cycle performance, temperature gradient and compressor discharge gas temperature can also be cited. In the present invention, the performance of the working medium is evaluated using the above four items as indicators. Specifically, a reference refrigeration cycle under the following temperature conditions is used. For example, each item is measured by the method described later, and except for the temperature gradient, it is evaluated as a relative value based on the value of R410A as the replacement object. A specific description of the following evaluation is given.

[0054] (Temperature conditions of the reference refrigeration cycle)

[0055] Evaporation temperature; -15°C (where, in the case of azeotropic mixture, it is the average temperature of the evaporation start temperature and the evaporation end temperature)

[0056] Condensation end temperature; 30°C (where, in the case of azeotropic mixture, it is the average temperature of the condensation start temperature and the condensation end temperature)

[0057] Subcooling degree (SC); 5°C

[0058] Superheat (SH); 0 °C

[0059] (B) Relative refrigerating capacity; hereinafter referred to as "RQ" R410A ".

[0060] The refrigerating capacity is the output power in the refrigeration cycle system. The relative refrigerating capacity with respect to R410A can be obtained by the following formula (2). In addition, in formula (2), the sample represents the working medium to be relatively evaluated.

[0061] [Equation 3]

[0062]

[0063] (C) Relative coefficient of performance; hereinafter referred to as "RCOP" R410A ".

[0064] The coefficient of performance is the value obtained by dividing the output power (kW) by the power (kW) consumed to obtain the output power (kW), which is equivalent to the energy consumption efficiency. The higher the value of the coefficient of performance, the greater the output power that can be obtained with less input. The relative coefficient of performance with respect to R410A can be obtained by the following formula (1). In addition, in formula (1), the sample represents the working medium to be relatively evaluated.

[0065] [Equation 4]

[0066]

[0067] (D) Temperature gradient

[0068] The temperature gradient is an index for measuring the difference in the composition of the working medium of the mixture in the liquid phase and the gas phase. The temperature gradient is defined as the property that the start temperature and the end temperature of evaporation in an evaporator or condensation in a condenser, which are heat exchangers, are different. In an azeotropic mixture medium, the temperature gradient is 0, and in an approximately azeotropic mixture such as R410A, the temperature gradient is extremely close to 0.

[0069] If the temperature gradient is large, for example, there is a problem that the possibility of frosting due to a decrease in the inlet temperature in the evaporator increases. Moreover, in a thermal cycle system, in order to improve the heat exchange efficiency, the working medium flowing through the heat exchanger and a heat source fluid such as water or air usually flow in opposite directions. Since the temperature difference of the heat source fluid is small in the stable operation state, it is difficult to obtain a thermal cycle system with excellent energy efficiency in the case of a non-azeotropic mixture medium with a large temperature gradient. Therefore, when using a mixture as the working medium, a working medium with an appropriate temperature gradient is desired.

[0070] In addition, there is a problem that the composition of non-azeotropic mixed media changes when filling the refrigeration and air conditioning equipment from the pressure container. In addition, in the event of refrigerant leakage from the refrigeration and air conditioning equipment, the refrigerant composition in the refrigeration and air conditioning equipment is likely to change, making it difficult to restore the refrigerant composition to the initial state. On the other hand, if it is an azeotropic or near-azeotropic mixed medium, the above problem can be avoided.

[0071] (E) Compressor discharge gas temperature difference TΔ

[0072] The compressor discharge gas temperature (Tx) of the sample, i.e., the working medium to be relatively evaluated, is subtracted from the compressor discharge gas temperature (Tx) of R410A. R410A ) is evaluated by the value (TΔ) obtained by calculating the value of the above equation. The temperature of the gas discharged from the compressor in the refrigeration cycle (hereinafter referred to as the "discharge temperature") is the highest temperature in the refrigeration cycle. The material constituting the compressor preferably has a low discharge temperature, considering the influence on the heat resistance of the refrigeration oil and polymer materials usually contained in the composition for the heat cycle system in addition to the working medium. In order to replace R410A, even if the discharge temperature is lower or higher than the discharge temperature of R410A, it must be a temperature allowed by the equipment constituting the heat cycle system originally operated with R410A.

[0073] The evaluation results of the four items (B) to (E) for HFO-1123 are shown in Table 2 together with the GWP of (A) and the result of R410A. In addition, the results of HFC-32, which has the lowest GWP among the HFCs that can be safely used alone, are shown in Table 2.

[0074] As mentioned above, HFO-1123 has a very low GWP. On the other hand, when used in a heat cycle system as a substitute for R410A, in the use of HFO-1123 alone as shown in Table 2 below, considering the RCOP R410A Sometimes the requirements will be further raised.

[0075] In the working medium, in order to improve the cycle performance or the impact on the greenhouse effect, a mixed medium of two or more compounds is often formed, such as R410A. For HFO-1123, various compositions are adjusted according to the application while balancing the cycle performance, temperature gradient, impact on the greenhouse effect, etc.

[0076] Since the GWP of HFO-1123 is extremely small as described above, when obtaining a mixed composition in combination with an HFC having high cycle performance and high GWP for improving cycle performance, for example, there are advantages in terms of suppressing the GWP to a low level and improving the cycle performance compared to other HFOs. Moreover, the working medium HFO-1123 used in the heat cycle system composition of the present invention has a GWP of less than 675, which is a working medium with a low GWP that HFCs cannot achieve.

[0077] [Table 2]

[0078]

[0079] The GWP of the working medium containing HFO-1123 used in the present invention is < 675. The GWP is preferably 500 or less, more preferably 300 or less, and particularly preferably 150 or less.

[0080] Moreover, the relative refrigerating capacity RQ of the working medium containing HFO-1123 used in the present invention R410A is preferably 0.70 to 1.50, more preferably 0.90 to 1.50, and particularly preferably 1.00 to 1.50.

[0081] (C) 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. (D) The temperature gradient is 11°C or less, preferably 9°C or less, more preferably 8°C or less, further preferably 5°C or less, particularly preferably 3°C or less, and most preferably 1°C or less.

[0082] (E) Discharge temperature difference TΔ is preferably 30°C or less, more preferably 20°C or less, and particularly preferably 10°C or less.

[0083] The relationship of the preferred ranges of these items (A) to (E) is shown in Table 3. In Table 3, for each item, the preferred condition ranges are defined in the order of (1) → (2) → (3) → (4). (4) represents the most preferred range. In addition, the condition that (F) the heat of combustion is less than 19 MJ / kg is also described in Table 3. The heat of combustion represents the heat generated along with the combustion reaction. Since in the American standard ASHRAE34 standard, the case where the heat of combustion is 19 MJ / kg or more is classified as a strongly flammable category with strong flammability, it is preferably less than 19 MJ / kg.

[0084] [Table 3]

[0085]

[0086] The working medium containing HFO-1123 used in the present invention must satisfy the conditions of (A)-(1) in Table 3. In addition, there is no particular limitation on the combination of each level in each item. Additionally, the most preferred is the working medium that satisfies all the conditions of (A)-(4), (B)-(3), (C)-(3), (D)-(4), (E)-(3), and (F)-(1).

[0087] As the refrigeration cycle system used for the above evaluation, for example, the refrigeration cycle system Figure 1 shown in the brief structural diagram can be used. Hereinafter, using Figure 1 the refrigeration cycle system shown, the methods for evaluating the cycle performance, temperature gradient, and compressor discharge gas temperature (Tx) will be described.

[0088] Figure 1 The refrigeration cycle system 10 shown generally includes a compressor 11 that compresses the working medium vapor A into a high-temperature and high-pressure working medium vapor B, a condenser 12 that cools and liquefies the working medium vapor B discharged from the compressor 11 into a low-temperature and high-pressure working medium C, an expansion valve 13 that expands the working medium C discharged from the condenser 12 into a low-temperature and low-pressure working medium D, an evaporator 14 that heats the working medium D discharged from the expansion valve 13 into a high-temperature and low-pressure working medium vapor A, 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.

[0089] The following cycle of (i) to (iv) is repeated in the refrigeration cycle system 10.

[0090] (i) Compress the working medium vapor A discharged from the evaporator 14 into a high-temperature and high-pressure working medium vapor B using the compressor 11 (hereinafter referred to as the "AB process").

[0091] (ii) Cool and liquefy the working medium vapor B discharged from the compressor 11 into a low-temperature and high-pressure working medium C using the condenser 12 with the fluid F. At this time, the fluid F is heated into the fluid F' and discharged from the condenser 12 (hereinafter referred to as the "BC process").

[0092] (iii) Expand the working medium C discharged from the condenser 12 into a low-temperature and low-pressure working medium D using the expansion valve 13 (hereinafter referred to as the "CD process").

[0093] (iv) Heat the working medium D discharged from the expansion valve 13 into a high-temperature and low-pressure working medium vapor A using the evaporator 14 with the load fluid E. At this time, the load fluid E is cooled into the load fluid E' and discharged from the evaporator 14 (hereinafter referred to as the "DA process").

[0094] The refrigeration cycle system 10 is a cycle system composed of adiabatic, isentropic change, isenthalpic change, and isobaric change. If the state change of the working medium is recorded on the Figure 2 pressure-enthalpy line (curve) diagram shown, it can be represented as a trapezoid with A, B, C, and D as vertices.

[0095] The AB process is an adiabatic compression using the compressor 11 to convert the working medium vapor A at high temperature and low pressure into the working medium vapor B at high temperature and high pressure, which is represented by the AB line in Figure 2 . As described later, the working medium vapor A is introduced into the compressor 11 in the superheated state, and the obtained working medium vapor B is also in the superheated state. The compressor discharge gas temperature (discharge temperature) is the temperature (Tx) of the state of B in Figure 2 , which is the highest temperature in the refrigeration cycle.

[0096] The BC process is an isobaric cooling using the condenser 12 to convert the working medium vapor B at high temperature and high pressure into the working medium C at low temperature and high pressure, which is represented by the BC line in Figure 2 . The pressure at this time is the condensation pressure. Among the intersections of the pressure-enthalpy line and the BC line, the intersection T1 on the high-enthalpy side is the condensation temperature, and the intersection T2 on the low-enthalpy side is the condensation boiling point temperature. Here, when the working medium is a non-azeotropic mixture medium, the temperature gradient is represented by the difference between T1 and T2.

[0097] The CD process is an isenthalpic expansion using the expansion valve 13 to convert the working medium C at low temperature and high pressure into the working medium D at low temperature and low pressure, which is represented by the CD line in Figure 2 . In addition, if the temperature of the working medium C at low temperature and high pressure is represented by T3, then T2 - T3 is the degree of subcooling (SC) of the working medium in the cycle of (i) to (iv).

[0098] The DA process is an isobaric heating using the evaporator 14 to restore the working medium D at low temperature and low pressure to the working medium vapor A 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. Among the intersections of the pressure-enthalpy line and the DA line, the intersection T6 on the high-enthalpy side is the evaporation temperature. If the temperature of the working medium vapor A is represented by T7, then T7 - T6 is the degree of superheat (SH) of the working medium in the cycle of (i) to (iv). In addition, T4 represents the temperature of the working medium D.

[0099] For the Q and COP of the working medium, if the enthalpies h A , h B , h C , h D, can be calculated respectively by the following formulas (11) and (12).

[0100] It is considered that there is no loss caused by machine efficiency, as well as pressure losses in piping and heat exchangers.

[0101] The thermodynamic properties necessary for calculating the thermal cycle performance of the working medium can be calculated according to the generalized equation of state (Soave-Redlich-Kwong equation) based on the principle of corresponding states and various thermodynamic relationships. In the case where characteristic values cannot be obtained, a prediction method based on the group contribution method is used for calculation.

[0102] Q = h A -h D …(11)

[0103] COP = Q / compression work = (h A -h D ) / (h B -h A )…(12)

[0104] The Q represented by the above (h A -h D ) is equivalent to the output power (kW) of the refrigeration cycle, and the compression work represented by (h B -h A ), for example, the electric power required to operate the compressor, is equivalent to the consumed power (kW). In addition, Q means the capacity of the refrigeration load fluid, and the higher Q is, the more work can be done in the same system. In other words, it means that when Q is large, the target performance can be obtained with a small amount of working medium, and the system can be miniaturized.

[0105] As the thermal cycle system applicable to the composition for a thermal cycle system of the present invention, a thermal cycle system based on heat exchangers such as condensers and evaporators can be used without limitation. The thermal cycle system, for example, in a refrigeration cycle, has a structure in which a compressor compresses a gaseous working medium, a condenser cools it to produce a high-pressure liquid, an expansion valve reduces the pressure, an evaporator vaporizes it at a low temperature, and heat is taken away by the heat of vaporization.

[0106] <Composition of the working medium>

[0107] The composition for a thermal cycle system of the present invention described above includes a working medium containing HFO-1123, and the GWP of this working medium is less than 675.

[0108] The working medium of the present invention may, in addition to HFO-1123, optionally include the following components as needed. The content of HFO-1123 in the working medium is preferably 20% by mass or more, more preferably 20 - 80% by mass, and still more preferably 40 - 60% by mass based on 100% by mass of the working medium.

[0109] As optional compounds (optional components), for example, HFCs, HFOs other than HFO-1123 (HFCs having a carbon-carbon double bond), and other components that are vaporized and liquefied together with HFO-1123 can be cited. As the optional component, HFOs other than HFCs and HFO-1123 (HFCs having a carbon-carbon double bond) are preferred.

[0110] As an optional component, when combined with HFO-1123 and used in a heat cycle, a compound that preferably has the effect of further improving the above relative efficiency coefficient and relative refrigerating capacity while keeping the GWP or temperature gradient and discharge temperature difference TΔ within an allowable range is preferred. If the working medium contains a combination of such a compound and HFO-1123, while maintaining the GWP at a low level, better cycle performance can be obtained, and the effects of the temperature gradient and discharge temperature difference are also small.

[0111] (HFC)

[0112] The HFC as an optional component is preferably selected according to the above viewpoints. As the HFC combined with HFO-1123, it is particularly preferably appropriately selected from the viewpoint of improving the cycle performance of the above working medium and keeping the temperature gradient within an appropriate range, especially from the viewpoint of keeping the GWP within an allowable range.

[0113] As an HFC with less impact on the ozone layer and less impact on the greenhouse effect, specifically, HFCs having 1 to 5 carbon atoms are preferred. The HFC can be linear, branched or cyclic.

[0114] Examples of HFCs include difluoromethane (HFC-32), difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane (HFC-125), pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, heptafluorocyclopentane, etc.

[0115] Among them, as HFCs, from the aspects of less impact on the ozone layer and excellent refrigeration cycle characteristics, HFC-32, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoroethane (HFC-134a), and HFC-125 are preferred, and HFC-32, HFC-152a, HFC-134a, and HFC-125 are more preferred.

[0116] The HFC can be used alone or in combination of two or more.

[0117] The content of HFC in the working medium (100% by mass) can be arbitrarily selected according to the required characteristics of the working medium. For example, in the case of a working medium composed of HFO-1123 and HFC-32, the relative efficiency coefficient is increased by making the content of HFC-32 within the range of 1 to 99% by mass. In the case of a working medium composed of HFO-1123 and HFC-134a, while suppressing the GWP within the above range, the relative efficiency coefficient is increased by making the content of HFC-134a 1 to 47% by mass.

[0118] In addition, from the aspect of suppressing the GWP of the obtained working medium to a low level, as an optional component, HFC-32 is most preferred.

[0119] In addition, HFO-1123 and HFC-32 can form an approximate azeotropic mixture close to azeotropic within the composition range of 99:1 to 1:99 by mass ratio, and the temperature gradient of the mixture of the two is close to 0 in almost any composition range. In this regard, as the HFC combined with HFO-1123, HFC-32 is advantageous.

[0120] In the working medium used in the present invention, when HFC-32 is used together with HFO-1123, the content of HFC-32 relative to 100% by mass of the working medium is specifically preferably 20% by mass or more, more preferably 20 to 80% by mass, and further preferably 40 to 60% by mass.

[0121] (HFO other than HFO-1123)

[0122] As the HFO as an optional component other than HFO-1123, it is also preferably selected from the same viewpoints as the above-mentioned HFC. In addition, even if it is not HFO-1123, as long as it is HFO, the GWP is very low compared with HFC. Therefore, as the HFO other than HFO-1123 combined with HFO-1123, compared with considering the GWP, it is more preferably appropriately selected in such a way as to particularly pay attention to improving the cycle performance of the above-mentioned working medium and keeping the temperature gradient and the discharge temperature difference TΔ within an appropriate range.

[0123] Examples of HFOs other than HFO-1123 include 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2-difluoroethylene (HFO-1132), 2-fluoropropene (HFO-1261yf), 1,1,2-trifluoropropene (HFO-1243yc), trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(E)), cis-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z)), trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)), 3,3,3-trifluoropropene (HFO-1243zf), and the like.

[0124] In addition, in the present invention, HFO-1234ze(E) and HFO-1234ze(Z) are collectively referred to as 1,3,3,3-tetrafluoropropene (HFO-1234ze).

[0125] Among them, as HFOs other than HFO-1123, considering the aspects of having a high critical temperature, excellent safety, and excellent efficiency coefficient, HFO-1234yf, HFO-1234ze(E), and HFO-1234ze(Z) are preferred, and HFO-1234yf and HFO-1234ze(E) are more preferred. The particularly preferred HFO is HFO-1234ze(E). HFOs other than HFO-1123 can be used alone or in combination of two or more.

[0126] The content of HFOs other than HFO-1123 in the working medium (100% by mass) can be arbitrarily selected according to the required characteristics of the working medium. For example, in the case of a working medium composed of HFO-1123 and HFO-1234yf or HFO-1234ze, by making the content of HFO-1234yf or HFO-1234ze within the range of 1 to 99% by mass, the efficiency coefficient can be improved.

[0127] In the case of a working medium containing HFO-1123 and HFO-1234yf, for example, from the aspects of balance cycle ability, temperature gradient, discharge temperature difference, and GWP, it is preferred that the total proportion of HFO-1123 and HFO-1234yf (or HFO-1234ze) relative to the total amount of the working medium is 70 to 100% by mass, and the proportion of HFO-1234yf (or HFO-1234ze) relative to the total amount of HFO-1123 and HFO-1234yf (or HFO-1234ze) is 5 to 65% by mass.

[0128] The working medium used in the present invention may be a combination of HFO-1123, HFC, and HFO other than HFO-1123. In this case, the working medium is preferably a working medium including HFO-1123, HFC-32, and HFO-1234yf (or HFO-1234ze).

[0129] When the HFO other than HFO-1123 is HFO-1234yf, the proportion of each compound in the total amount of the working medium including HFO-1123, HFC-32, and HFO-1234yf is more preferably in the following range.

[0130] 20% by mass ≤ HFO-1123 ≤ 80% by mass

[0131] 10% by mass ≤ HFC-32 ≤ 75% by mass

[0132] 5% by mass ≤ HFO-1234yf ≤ 50% by mass

[0133] The working medium including HFO-1123, HFC-32, and HFO-1234yf is more preferably a working medium composed of HFO-1123, HFC-32, and HFO-1234yf.

[0134] In addition, when the HFO other than HFO-1123 is HFO-1234ze, the proportion of each compound in the total amount of the working medium including HFO-1123, HFC-32, and HFO-1234ze is more preferably in the following range.

[0135] 10% by mass ≤ HFO-1123 ≤ 80% by mass

[0136] 10% by mass ≤ HFC-32 ≤ 80% by mass

[0137] 5% by mass ≤ HFO-1234ze ≤ 45% by mass

[0138] The working medium including HFO-1123, HFC-32, and HFO-1234ze is more preferably a working medium composed of HFO-1123, HFC-32, and HFO-1234ze. In addition, HFO-1234ze is preferably HFO-1234ze(E).

[0139] (Other optional components)

[0140] The working medium used in the composition for the thermal cycle system of the present invention may further include carbon dioxide, hydrocarbons, chlorofluorocarbons (CFO), hydrochlorofluorocarbons (HCFO), etc. in addition to the above-mentioned optional components. As other optional components, components with less impact on the ozone layer and less impact on the greenhouse effect are preferred.

[0141] Examples of hydrocarbons include propane, propylene, cyclopropane, butane, isobutane, pentane, isopentane, etc.

[0142] The hydrocarbon can be used alone or in combination of two or more.

[0143] When the above working medium includes a hydrocarbon, its content is less than 10% by mass relative to 100% by mass of the working medium, preferably 1 - 5% by mass, and more preferably 3 - 5% by mass. If the hydrocarbon is above the lower limit, the solubility of the mineral oil refrigerant in the working medium becomes better.

[0144] Examples of CFOs include chlorofluoropropene, chlorofluoroethylene, etc. Considering aspects such as not significantly reducing the circulation performance of the working medium and easily suppressing the flammability of the working medium, as CFOs, 1,1 - dichloro - 2,3,3,3 - tetrafluoropropene (CFO - 1214ya), 1,3 - dichloro - 1,2,3,3 - tetrafluoropropene (CFO - 1214yb), and 1,2 - dichloro - 1,2 - difluoroethylene (CFO - 1112) are preferred.

[0145] The CFO can be used alone or in combination of two or more.

[0146] When the above working medium includes a CFO, its content is less than 10% by mass relative to 100% by mass of the working medium, preferably 1 - 8% by mass, and more preferably 2 - 5% by mass. If the content of the CFO is above the lower limit, it is easy to suppress the flammability of the working medium. If the content of the CFO is below the upper limit, it is easy to obtain good circulation performance.

[0147] Examples of HCFOs include hydrochlorofluoropropene, hydrochlorofluoroethylene, etc. Considering aspects such as not significantly reducing the circulation performance of the working medium and easily suppressing the flammability of the working medium, as HCFOs, 1 - chloro - 2,3,3,3 - tetrafluoropropene (HCFO - 1224yd) and 1 - chloro - 1,2 - difluoroethylene (HCFO - 1122) are preferred.

[0148] The HCFO can be used alone or in combination of two or more.

[0149] When the above working medium includes an HCFO, the content of the HCFO in 100% by mass of the working medium is less than 10% by mass, preferably 1 - 8% by mass, and more preferably 2 - 5% by mass. If the content of the HCFO is above the lower limit, it is easy to suppress the flammability of the working medium. If the content of the HCFO is below the upper limit, it is easy to obtain good circulation performance.

[0150] When the working medium used in the composition for a thermal cycle system of the present invention contains any other components as described above, the total content of any other components in the working medium is less than 10% by mass, preferably 8% by mass or less, and more preferably 5% by mass or less, based on 100% by mass of the working medium.

[0151] In addition to the above working medium, the composition for a thermal cycle system of the present invention contains a refrigeration oil in the same manner as a typical composition for a thermal cycle system. The composition for a thermal cycle system containing a working medium and a refrigeration oil may further contain known additives such as a stabilizer and a leak detection substance.

[0152] <Refrigeration oil>

[0153] As the refrigeration oil, a known refrigeration oil used in a composition for a thermal cycle system together with a conventional working medium composed of a halogenated hydrocarbon can be employed without limitation. Specifically, examples of the refrigeration oil include oxygen-containing synthetic oils (such as ester-based refrigeration oils and ether-based refrigeration oils), fluorine-based refrigeration oils, mineral-based refrigeration oils, and hydrocarbon-based synthetic oils.

[0154] Examples of the ester-based refrigeration oil include dibasic acid ester oils, polyol ester oils, complex ester oils, and polyol carbonate oils.

[0155] As the dibasic acid ester oil, an ester of a dibasic acid having 5 to 10 carbon atoms (such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.) and a monohydric alcohol having 1 to 15 carbon atoms with a straight-chain or branched alkyl group (such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, etc.) is preferred. Specifically, examples include bis(tridecyl) glutarate, bis(2-ethylhexyl) adipate, diisodecyl adipate, bis(tridecyl) adipate, bis(3-ethylhexyl) sebacate, etc.

[0156] As the polyol ester oil, an ester of a diol (such as 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 a polyol having 3 to 20 hydroxyl groups (such as trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, glycerol, sorbitol, sorbitan, sorbitol glycerol condensate, etc.) and a fatty acid having 6 to 20 carbon atoms (such as a straight-chain or branched fatty acid such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, eicosanoic acid, oleic acid, etc., or a so-called neo acid in which the α-carbon atom is a quaternary carbon) is preferred.

[0157] In addition, these polyol ester oils may also have free hydroxyl groups.

[0158] As polyol ester oils, esters of hindered alcohols (such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, etc.) (such as trimethylolpropane trinonanoate, pentaerythritol 2-ethylhexanoate, pentaerythritol tetranonanoate, etc.) are preferred.

[0159] Complex ester oils refer to esters of fatty acids, dibasic acids, monohydric alcohols, and polyhydric alcohols. The same ones as those described above can be used as the fatty acids, dibasic acids, monohydric alcohols, and polyhydric alcohols.

[0160] Polyol carbonate oils refer to esters of carbonic acid and polyhydric alcohols.

[0161] As the polyhydric alcohol, the same diols as those described above or the same polyhydric alcohols as those described above can be exemplified. In addition, as the polyol carbonate oil, it can be a ring-opening polymer of cyclic alkylene carbonate.

[0162] As ether-type refrigeration oils, polyvinyl ether oils and polyoxyalkylene oils can be exemplified.

[0163] As polyvinyl ether oils, there are those obtained by polymerizing vinyl ether monomers such as alkyl vinyl ethers, and copolymers obtained by copolymerizing vinyl ether monomers and hydrocarbon monomers having an olefinic double bond.

[0164] One type of vinyl ether monomer can be used alone, or two or more types can be used in combination.

[0165] As the hydrocarbon monomers having an olefinic double bond, ethylene, propylene, various butenes, various pentenes, various hexenes, various heptenes, various octenes, diisobutene, triisobutene, styrene, α-methylstyrene, various alkyl-substituted styrenes, etc. can be exemplified. One type of hydrocarbon monomer having an olefinic double bond can be used alone, or two or more types can be used in combination.

[0166] The polyvinyl ether copolymer can be either a block copolymer or a random copolymer. One type of polyvinyl ether oil can be used alone, or two or more types can be used in combination.

[0167] As polyoxyalkylene oils, polyoxyalkylene monohydric alcohols, polyoxyalkylene polyhydric alcohols, alkyl ether compounds of polyoxyalkylene monohydric alcohols or polyoxyalkylene polyhydric alcohols, ester compounds of polyoxyalkylene monohydric alcohols or polyoxyalkylene polyhydric alcohols, etc. can be exemplified.

[0168] The polyoxyalkylene monohydric alcohol or polyoxyalkylene polyhydric alcohol can be exemplified by alcohols obtained by a method such as ring-opening addition polymerization of alkylene oxides having 2 to 4 carbon atoms (such as ethylene oxide, propylene oxide, etc.) to initiators such as water or hydroxyl group-containing compounds in the presence of catalysts such as alkali hydroxides. In addition, the alkylene oxide units in the polyalkylene chain can be the same in one molecule or can contain two or more types of alkylene oxide units. It is preferred to contain at least propylene oxide units in one molecule.

[0169] As initiators for the reaction, examples include water, monohydric alcohols such as methanol or butanol, and polyhydric alcohols such as ethylene glycol, propylene glycol, pentaerythritol, and glycerol.

[0170] As polyoxyalkylene oils, polyoxyalkylene monohydric alcohol or alkyl etherified or esterified products of polyoxyalkylene polyhydric alcohols are preferred. In addition, as polyoxyalkylene polyhydric alcohols, polyoxyalkylene diols are preferred. Particularly preferred is an alkyl etherified product of a polyoxyalkylene diol in which the terminal hydroxyl groups of the polyoxyalkylene diol called polyglycol oil are covered with an alkyl group such as methyl.

[0171] As fluorine-based refrigeration oils, examples include compounds in which hydrogen atoms of synthetic oils (mineral oils, polyalpha-olefins, alkylbenzenes, alkylnaphthalenes, etc., described later) are replaced by fluorine atoms, perfluoropolyether oils, fluorinated organosilicon oils, etc.

[0172] As mineral-based refrigeration oils, examples 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 (such as deasphalting, solvent extraction, hydrocracking, solvent dewaxing, contact dewaxing, hydrorefining, clay treatment, etc.) in an appropriate combination.

[0173] As hydrocarbon synthetic oils, examples include polyalpha-olefins, alkylbenzenes, alkylnaphthalenes, etc.

[0174] The refrigeration oil can be used alone or in combination of two or more.

[0175] As the refrigeration oil, from the aspect of compatibility with the working medium, one or more selected from polyol ester oils, polyvinyl ether oils, and polyglycol oils are preferred.

[0176] The content of the refrigeration oil in the composition for the thermal cycle system may be within the range that does not significantly reduce the effects of the present invention. Relative to 100 parts by mass of the working medium, it is preferably 10 to 100 parts by mass, more preferably 20 to 50 parts by mass.

[0177] <Any other components>

[0178] The stabilizer optionally contained in the composition for the thermal cycle system is a component that improves the stability of the working medium against heat and oxidation. As the stabilizer, any known stabilizer used in the thermal cycle system together with the conventional working medium composed of halogenated hydrocarbons, such as oxidation resistance improvers, heat resistance improvers, metal deactivators, etc., can be used without particular limitation.

[0179] Examples of the oxidation resistance improver and heat resistance improver 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 improver and heat resistance improver may be used alone or in combination of two or more kinds.

[0180] Examples of the metal deactivator include imidazole, benzimidazole, 2-mercaptobenzothiazole, 2,5-dimercaptothiadiazole, salicylidene-propylenediamine, pyrazole, benzotriazole, tolyltriazole, 2-methylbenzimidazole, 3,5-dimethylpyrazole, methylenebis-benzotriazole, organic acid or its ester, primary, secondary or tertiary aliphatic amine, amine salt of organic acid or inorganic acid, nitrogen-containing heterocyclic compound, amine salt of alkyl phosphate or its derivative, etc.

[0181] The content of the stabilizer in the composition for the thermal circulation system may be within the range that does not significantly reduce the effects of the present invention. Preferably, it is 5 parts by mass or less, more preferably 1 part by mass or less, relative to 100 parts by mass of the working medium.

[0182] Examples of the leakage detection substance optionally contained in the composition for the thermal circulation system include ultraviolet fluorescent dye, odor gas or odor masking agent, etc.

[0183] Examples of the ultraviolet fluorescent dye include the known ultraviolet fluorescent dyes described in U.S. Patent No. 4,249,412, Japanese Patent Application Laid-Open No. Hei 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., which have been used in the thermal circulation system together with the working medium composed of halogenated hydrocarbon in the past.

[0184] Examples of the odor masking agent include the known fragrances described in Japanese Patent Application Laid-Open No. 2008-500437, Japanese Patent Application Laid-Open No. 2008-531836, etc., which have been used in the thermal circulation system together with the working medium composed of halogenated hydrocarbon in the past.

[0185] When using the leakage detection substance, a solubilizer that improves the solubility of the leakage detection substance in the working medium can be used.

[0186] As the solubilizing agent, the solubilizing agents described in JP-A-2007-511645, JP-A-2008-500437 and JP-A-2008-531836 may be mentioned.

[0187] The content of the leakage detection substance in the thermal cycle system composition may be within a range that does not significantly reduce the effect of the present invention, and is preferably 2 parts by mass or less, more preferably 0.5 parts by mass or less, based on 100 parts by mass of the working medium.

[0188] [Thermal circulation system]

[0189] The heat cycle system of the present invention is a system using the composition for the heat cycle system of the present invention. The heat cycle system of the present invention may be a heat pump system using a warm heat source (Japanese: 溫熱) obtained from a condenser, or a refrigeration cycle system using a cold heat source (Japanese: 冷熱) obtained from an evaporator.

[0190] Specifically, the heat cycle system of the present invention may be used as a refrigerating and freezing machine, an air conditioning machine, a power generation system, a heat transport device, a secondary cooling machine, etc. Among them, since the heat cycle performance can be stably and safely exerted even in a higher temperature working environment, the heat cycle system of the present invention is preferably used as an air conditioning machine that is often installed outdoors, etc. In addition, the heat cycle system of the present invention is also preferably used as a refrigerating and freezing machine.

[0191] Specific examples of the air conditioning equipment include room air conditioners, central air conditioners (central air conditioners for shops, central air conditioners for buildings, central air conditioners for facilities, etc.), gas engine heat pumps, train air conditioners, and automobile air conditioners.

[0192] Specific examples of the freezing / refrigerating machine include display cabinets (built-in display cabinets, separate display cabinets, etc.), commercial freezing / refrigerating cabinets, vending machines, ice machines, and the like.

[0193] As the power generation system, a power generation system using a Rankine cycle system is preferably used.

[0194] Specifically, as a power generation system, there can be exemplified a system in which geothermal energy, solar heat, medium to high temperature waste heat of about 50 to 200°C, etc. are used to heat the working medium in an evaporator, an expander is used to adiabatically expand the working medium which is a steam in a high temperature and high pressure state, and a generator is driven by the work done by the adiabatic expansion to generate electricity.

[0195] Furthermore, the heat cycle system of the present invention may be a heat transport device. As the heat transport device, a latent heat transport device is preferred.

[0196] As a latent heat transfer device, examples include a heat pump that uses evaporation, boiling, condensation, etc. of a working medium sealed in the device to perform latent heat transfer, and a two-phase sealed thermosyphon device. The heat pump is used in small cooling devices such as cooling devices for heat generating parts of semiconductor elements or electronic devices. Since the two-phase sealed thermosyphon does not require a wick and has a simple structure, it can be widely used in gas-gas heat exchangers, snow melting promotion and anti-freezing of roads, etc.

[0197] In addition, when the heat cycle system is operating, in order to avoid problems caused by the mixing of moisture or non-condensable gases such as oxygen, it is preferable to provide a method for suppressing the mixing of these substances.

[0198] If moisture mixes into the heat cycle system, problems will occur especially when used at low temperatures. For example, problems such as ice formation in the capillary, hydrolysis of the working medium or refrigerant oil, material deterioration caused by acid components generated in the cycle, and generation of contaminants will occur. In particular, when the refrigerant oil is polyglycol oil, polyol ester oil, etc., it has extremely high hygroscopicity and is prone to hydrolysis reaction, which is an important reason for the decline of the characteristics of the refrigerant oil and the damage of 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 heat cycle system.

[0199] As a method for controlling the moisture concentration in the heat cycle system, examples include methods using moisture removal means such as desiccants (silica gel, activated alumina, zeolite, etc.). From the aspect of dehydration efficiency, it is preferable to bring the desiccant into contact with the liquid heat cycle system composition. For example, it is preferable to dispose the desiccant at the outlet of the condenser 12 or the inlet of the evaporator 14 so that it comes into contact with the heat cycle system composition.

[0200] As the desiccant, from the aspects of the chemical reactivity between the desiccant and the heat cycle system composition and the moisture absorption capacity of the desiccant, zeolite desiccants are preferable.

[0201] As the zeolite desiccant, in the case of using a refrigerant oil with a higher moisture absorption amount than conventional mineral refrigerant oils, from the aspect of excellent moisture absorption capacity, a zeolite desiccant mainly composed of a compound represented by the following formula (3) is preferable.

[0202] M 2 / n O·Al2O3·xSiO2·yH2O…(3)

[0203] Among them, M is an element of Group IA such as Na, K, etc. or an element of Group IIA such as Ca, etc.; n is the valence of M; x and y are values determined by the crystal structure. The fine pore diameter can be adjusted by changing M.

[0204] In the selection of the desiccant, the fine pore diameter and the crushing strength are important.

[0205] When using a desiccant with a pore diameter smaller than the molecular diameter of the working medium contained in the heat cycle system composition, the working medium is adsorbed in the desiccant. As a result, chemical reactions occur between the working medium and the desiccant, leading to undesirable phenomena such as the generation of non-condensable gases, a decrease in the strength of the desiccant, and a decline in the adsorption capacity.

[0206] Therefore, as the desiccant, it is preferable to use zeolite-based desiccants with a small pore diameter. Sodium-potassium A-type synthetic zeolite with a pore diameter of 3.5 Å or less is particularly preferred. By using sodium-potassium A-type synthetic zeolite with a pore diameter smaller than the molecular diameter of the working medium, the working medium is not adsorbed, and only the moisture in the heat cycle system can be selectively adsorbed and removed. In other words, since it is difficult for the working medium to be adsorbed by the desiccant, thermal decomposition is not likely to occur. As a result, the deterioration of the materials constituting the heat cycle system and the generation of contaminants can be suppressed.

[0207] If the size of the zeolite-based desiccant is too small, it will cause blockage of the valves or fine parts of the piping in the heat cycle system. If it is too large, the drying capacity will decrease. Therefore, a size of about 0.5 to 5 mm is preferred. As the shape, granular or cylindrical shapes are preferred.

[0208] Zeolite-based desiccants can be made into any shape by consolidating powdered zeolite with a binder (such as bentonite). Within the range where the zeolite-based desiccant is the main body, other desiccants (such as silica gel and activated alumina) can be used in combination.

[0209] There is no particular limitation on the usage ratio of the zeolite-based desiccant relative to the heat cycle system composition.

[0210] Moreover, if non-condensable gases are mixed into the heat cycle system, it may cause poor heat transfer in the condenser or evaporator and an adverse effect of an increase in the working pressure. Therefore, it is necessary to strongly suppress their mixing. In particular, oxygen, one of the non-condensable gases, reacts with the working medium or the refrigerant oil, promoting decomposition.

[0211] The concentration of non-condensable gases in the gas phase part of the working medium is preferably 1.5 vol% or less, particularly preferably 0.5 vol% or less, based on the volume ratio relative to the working medium.

[0212] In the heat cycle system of the present invention described above, by using the working medium of the present invention, it has high safety, suppresses the impact on the greenhouse effect, has practically sufficient cycle performance, and there is no problem of temperature gradient.

[0213] Examples

[0214] The present invention will be described in detail below with reference to examples, but the present invention is not limited by the following examples.

[0215] [Examples 1 to 58]

[0216] In Examples 1 to 58, at least one of HFO-1123, HFO-1234yf, HFC-32, and HFC-134a was mixed in the ratios shown in Tables 4 to 7 to prepare a working medium, and the temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigerating capacity and relative coefficient of performance) were measured and calculated by the above-described method. The results are shown in Tables 4 to 7.

[0217] [Table 4]

[0218]

[0219] [Table 5]

[0220]

[0221] [Table 6]

[0222]

[0223] [Table 7]

[0224]

[0225] [Examples 59 to 94]

[0226] In Examples 59 to 94, HFO-1123, HFO-1234ze(E), and HFC-32 were mixed in the ratios shown in Table 8 to prepare a working medium, and the temperature gradient, discharge temperature difference, and refrigeration cycle performance (relative refrigerating capacity and relative coefficient of performance) were measured and calculated by the above-described method. The results are shown in Table 8.

[0227] [Table 8]

[0228]

[0229] Industrial Applicability

[0230] The composition for a thermal cycle system of the present invention and the thermal cycle system using the composition can be used in refrigeration and freezing machines (built-in display cabinets, separate display cabinets, commercial refrigeration and freezing warehouses, vending machines, ice makers, etc.), air conditioning machines (room air conditioners, commercial central air conditioners, building central air conditioners, equipment central air conditioners, gas engine heat pumps, train air conditioning units, automotive air conditioning units, etc.), power generation systems (waste heat recovery power generation, etc.), and heat transfer devices (heat pumps, etc.).

[0231] The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2014-030856, filed on February 20, 2014, are hereby incorporated by reference as the disclosure of the specification of the present invention.

[0232] Symbol Explanation

[0233] 10… Refrigeration cycle system, 11… Compressor, 12… Condenser, 13… Expansion valve, 14… Evaporator, 15, 16… Pumps.

Claims

1. A composition for a thermal cycling system, characterized in that, It is a composition for a thermal cycle system containing a working medium for thermal cycle, The working medium for thermal cycle is composed of trifluoroethylene and 2,3,3,3-tetrafluoropropene, The 100-year greenhouse effect coefficient of the working medium for thermal cycle in the 4th report of the Intergovernmental Panel on Climate Change (IPCC) is less than 675, The proportion of trifluoroethylene relative to the total amount of the working medium is 20% by mass or more.

2. The composition for a thermal cycling system according to claim 1, characterized in that, The proportion of trifluoroethylene relative to the total amount of the working medium is 20 - 80% by mass.

3. The composition for a thermal cycling system according to claim 1, characterized in that, The greenhouse effect coefficient is 150 or less.

4. The composition for a thermal cycling system according to claim 1, characterized in that, The relative efficiency coefficient RCOP of the working medium for the thermal cycle, calculated by the following formula (1) R410A is 0.85 to 1.20; [Number 1] In formula (1), R410A represents a mixture with a mass ratio of difluoromethane to pentafluoroethane of 1:1, the sample represents the working medium to be relatively evaluated, and the efficiency coefficients of the sample and R410A are values obtained by dividing the output power in kW obtained when they are respectively used in a reference refrigeration cycle with an evaporation temperature of -15°C, a condensation temperature of 30°C, a subcooling degree SC of 5°C, and a superheat degree SH of 0°C by the required electrical energy consumption in kW; wherein, in the case of azeotropic mixture, the evaporation temperature refers to the average temperature of the evaporation start temperature and the evaporation end temperature, and the condensation temperature refers to the average temperature of the condensation start temperature and the condensation end temperature.

5. The composition for a thermal cycling system according to claim 1, characterized in that, The temperature gradient of the working medium for thermal cycle is 8°C or less, and this temperature gradient is represented by the difference between the evaporation start temperature and the evaporation end temperature in the evaporator when used in a reference refrigeration cycle with an evaporation temperature of -15°C, a condensation temperature of 30°C, a subcooling degree SC of 5°C, and a superheat degree SH of 0°C; wherein, in the case of azeotropic mixture, the evaporation temperature refers to the average temperature of the evaporation start temperature and the evaporation end temperature, and the condensation temperature refers to the average temperature of the condensation start temperature and the condensation end temperature.

6. The composition for a thermal cycling system according to claim 1, characterized in that, The TΔ of the working medium for the thermal cycle is 30°C or less. This TΔ is the temperature Tx of the compressor discharge gas in a reference refrigeration cycle with an evaporation temperature of -15°C, a condensation temperature of 30°C, a subcooling degree SC of 5°C, and a superheat degree SH of 0°C, minus the temperature T of the compressor discharge gas when a mixture of difluoromethane and pentafluoroethane with a mass ratio of 1:1 is used in the reference refrigeration cycle. R410A In the case of a non-azeotropic mixture, the evaporation temperature refers to the average temperature of the evaporation start temperature and the evaporation end temperature, and the condensation temperature refers to the average temperature of the condensation start temperature and the condensation end temperature.

7. The composition for a thermal cycling system according to any one of claims 1 to 6, characterized in that, The combustion heat of the working medium for thermal cycle is less than 19 MJ / kg.

8. A thermal cycling system, characterized in that, Use the composition for a thermal cycle system according to any one of claims 1 - 7.

9. The thermal cycling system according to claim 8, characterized in that, The thermal cycle system is a refrigeration / refrigeration machine, an air-conditioning machine, a power generation system, a heat transfer device or a secondary cooler.

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