Ultra-low temperature refrigerant composition

Abstract

The present invention relates to a refrigerant composition for ultra-low temperatures, and more specifically, to a refrigerant composition for ultra-low temperatures comprising 1,1,1-trifluoroethane, pentafluoroethane, tetrafluoromethane, trifluoromethane, hexafluoroethane, and difluoromethane. The ultra-low temperature refrigerant composition containing the above components can be applied to existing refrigeration systems, such as ultra-low temperature freezers and freeze dryers, to generate ultra-low temperatures; therefore, it is not only economical and environmentally friendly but also exhibits excellent refrigeration efficiency and fluidity.

Description

Technology Field

[0001] The present invention relates to a refrigerant composition for ultra-low temperatures, and more specifically, to a refrigerant composition for ultra-low temperatures that is economical and environmentally friendly, as well as exhibiting excellent refrigeration efficiency and fluidity, because it can be applied to existing refrigeration systems such as ultra-low temperature freezers and freeze dryers to generate ultra-low temperatures. Background Technology

[0003] Chlorofluorocarbons (CFCs), commonly referred to as Freon, are compounds composed of carbon, fluorine, and chlorine. They have long been widely used as refrigerants, foaming agents, propellants, and cleaning agents due to their high stability—including low corrosiveness, low toxicity, and non-flammability—as well as their ease of phase transition between gas and liquid, their ability to dissolve organic matter, high penetrability, and electrical insulation, and their low cost.

[0004] However, as it became known that Freon in the atmosphere reaches the stratosphere and decomposes due to the light energy of short-wavelength ultraviolet rays, and that the chlorine atoms produced combine with ozone to destroy the ozone layer, which is the Earth's protective shield, its production and use are regulated by the Montreal Protocol.

[0005] Therefore, research on alternative refrigerants has been conducted worldwide in preparation for Freon regulations. Through this research, there have been attempts to develop new refrigerants and to manufacture new refrigerants with the same performance as the regulated refrigerants by mixing existing refrigerants. However, since developing refrigerants with new components requires significant cost and time, research on mixed refrigerants, which adjust the properties by mixing two or more types of gases, is actively underway.

[0006] However, even if we only mix the theoretically usable refrigerants among the unregulated refrigerants, the number of mixing combinations exceeds 100, and depending on each combination, when liquefaction or vaporization occurs between the liquid and gas phases under a certain pressure, there are some that do not change temperature in a quasi-equilibrium state like pure substances, while there are also mixed refrigerants whose temperature changes.

[0007] In particular, there are not many types of refrigerant gases capable of achieving ultra-low temperatures of -60℃ or lower inside a freezer, and refrigerants capable of achieving ultra-low temperatures generally have a higher critical pressure and lower critical temperature as their standard boiling point decreases, so there was a problem that they were difficult to apply easily in a room temperature environment. Prior art literature

[0009] Korean Registered Publication No. 10-1204722 (2012.11.20.) Korean Registered Publication No. 10-1605543 (2016.03.16.) The problem to be solved

[0010] The objective of the present invention is to provide a refrigerant composition for ultra-low temperatures that is economical and environmentally friendly, as well as exhibiting excellent refrigeration efficiency and fluidity, because it can be applied to existing refrigeration systems such as ultra-low temperature freezers and freeze dryers to generate ultra-low temperatures. means of solving the problem

[0012] The objective of the present invention can be achieved by providing a refrigerant composition for ultra-low temperatures characterized by comprising 1,1,1-trifluoroethane, pentafluoroethane, tetrafluoromethane, trifluoromethane, hexafluoroethane, and difluoromethane.

[0013] According to a more preferred feature of the present invention, the ultra-low temperature refrigerant composition may comprise 30 to 40 weight% of 1,1,1-trifluoroethane, 30 to 40 weight% of pentafluoroethane, 10 to 15 weight% of tetrafluoromethane, 5 to 10 weight% of trifluoromethane, 5 to 10 weight% of hexafluoroethane, and 4 to 9 weight% of difluoromethane, based on 100 weight% of the total composition.

[0014] According to a more preferred feature of the present invention, the ultra-low temperature refrigerant composition may further include 0.1 to 1 weight% of argon and 0.1 to 1 weight% of n-pentane based on 100 weight% of the total composition. Effects of the invention

[0016] The ultra-low temperature refrigerant composition according to the present invention is applied to existing refrigeration systems, such as ultra-low temperature freezers and freeze dryers, to generate ultra-low temperatures. As such, it is not only economical and environmentally friendly but also exhibits excellent effects by providing an ultra-low temperature refrigerant that demonstrates superior refrigeration efficiency and fluidity. Specific details for implementing the invention

[0018] Hereinafter, preferred embodiments of the present invention and the physical properties of each component are described in detail. This description is intended to be sufficient for a person skilled in the art to easily practice the invention, and does not imply that the technical scope and concept of the present invention are limited thereby.

[0020] The ultra-low temperature refrigerant composition according to the present invention comprises 1,1,1-trifluoroethane, pentafluoroethane, tetrafluoromethane, trifluoromethane, hexafluoroethane, and difluoromethane. Specifically, based on 100 weight% of the total composition, it may comprise 30 to 40 weight% of 1,1,1-trifluoroethane, 30 to 40 weight% of pentafluoroethane, 10 to 15 weight% of tetrafluoromethane, 5 to 10 weight% of trifluoromethane, 5 to 10 weight% of hexafluoroethane, and 4 to 9 weight% of difluoromethane.

[0021] In one embodiment, the 1,1,1-trifluoroethane is included in an amount of 30 to 40 weight percent, and is a hydrofluorocarbon refrigerant also known as HFC-143a. It serves to replace conventional Freon (CFC) or HCFC refrigerants, which have the problem of ozone layer depletion, thereby providing an environmentally friendly refrigerant while providing an excellent ultra-low temperature effect.

[0022] The above 1,1,1-trifluoroethane is relatively safe for the human body and the environment, but when used alone, the refrigerant pressure may become too high or too low. Therefore, when used together with tetrafluoromethane, trifluoromethane, hexafluoroethane, and difluoromethane as in the present invention, ultra-low temperature continuous cooling is possible due to the wide boiling point distribution, and the device operation can be stably performed due to the optimization of pressure and refrigeration capacity. Furthermore, safety is ensured due to the non-flammable composition, and it can have an advantageous effect in designing for compliance with environmental regulations.

[0023] If the content of the above 1,1,1-trifluoroethane is less than 30 weight%, the above effect is negligible, and if the content of the above 1,1,1-trifluoroethane exceeds 40 weight%, the above effect is not significantly improved, and the content of tetrafluoromethane, trifluoromethane, hexafluoroethane, and difluoromethane is excessively reduced, which not only lowers the synergistic effect but also may lower the ultra-low temperature performance of the refrigerant composition, so it is undesirable.

[0025] In one embodiment, the pentafluoroethane (1,1,1,2,2-pentafluoroethane) is included in an amount of 30 to 40 weight percent and is a hydrofluorocarbon refrigerant that does not deplete the ozone layer and is a fluorocarbon compound also known as R-125, which is used as a main component of various mixed refrigerants such as R404A, R410A, and R407C, and is also utilized as a fire extinguishing agent in some fire suppression systems.

[0026] In the present invention, the above 1,1,1-trifluoroethane is used as a main ingredient in a refrigerant composition for ultra-low temperature applications, and because it exhibits synergistic effects such as ensuring non-flammability, stabilizing vapor pressure, and supplementing refrigeration capacity (COP), it plays a role in providing an environmentally friendly refrigerant while providing excellent ultra-low temperature effects.

[0027] To explain in more detail, the above pentafluoroethane is non-flammable and is mixed with the above flammable 1,1,1-trifluoroethane to convert it into a non-flammable one. It is also included in commercial mixed refrigerants (R404A, R407A, R507A, etc.) to ensure safety, as it acts as a temperature bridge as an intermediate boiling point component.

[0028] In addition, while the presence of only low-boiling point components can lead to problems where the pressure becomes excessively high or low, the inclusion of the aforementioned pentafluoroethane causes the vapor pressure to converge to an intermediate value, thereby alleviating the design burden on compressors, valves, and heat exchangers.

[0029] In addition, because it has a large latent heat and stable pressure conditions, it maintains the refrigeration performance of the mixed refrigerant evenly, and when mixed with the above 1,1,1-trifluoroethane, it exhibits a complementary effect on the refrigeration efficiency (COP). The above pentafluoroethane has an intermediate molecular weight and high chemical stability, so when mixed with other components, it exhibits an effect of mitigating fractionation.

[0030] If the content of the above-mentioned pentafluoroethane is less than 30 weight%, the above effect is negligible, and if the content of the above-mentioned pentafluoroethane exceeds 40 weight%, the above effect is not significantly improved, and the content of 1,1,1-trifluoroethane, trifluoromethane, hexafluoroethane, and difluoromethane is excessively reduced, resulting in a decrease in ultra-low temperature performance due to a reduction in low-boiling point components, increased design burden on the heat exchanger, and increased risk of fractionation, which is undesirable.

[0032] In one embodiment, the tetrafluoromethane is included in an amount of 10 to 15 weight percent and is a type of fluorocarbon (F-gas) commercially known as the refrigerant number R-14, and can add a very low temperature, such as cryogenic temperature (-100°C or lower), thereby enabling the ultra-low temperature refrigerant composition according to the present invention to generate an ultra-low temperature.

[0033] In addition, it has low reactivity and does not react with other substances, so it does not damage cooling equipment. It exhibits high vapor pressure and low viscosity, providing rapid heat transfer and efficient cooling effects. However, since its refrigeration capacity (COP) as a refrigerant is limited when used alone, it is preferable to use it mixed with 1,1,1-trifluoroethane, pentafluoroethane, trifluoromethane, hexafluoroethane, and difluoromethane as in the present invention.

[0034] When the above tetrafluoromethane is included, it has a low boiling point, allowing sufficient vapor pressure to be secured even at low temperatures. When mixed with intermediate or high boiling point components, it balances the suction pressure and discharge pressure, thereby stabilizing the operation of the compressor. Furthermore, as a low boiling point component, it shifts the evaporation temperature of the refrigerant composition toward a lower level, mitigating the temperature difference with other components. This results in a synergistic effect where the evaporation-condensation curve of the ultra-low temperature mixture is smoothly connected, enabling the optimization of the heat exchanger design.

[0035] In addition, although the above tetrafluoromethane has a low COP when used alone, it can maintain refrigeration capacity in the cryogenic range when combined with other components, thereby supporting the COP of the refrigerant composition, and because it is a completely non-flammable component, it exhibits a synergistic effect that helps secure the non-flammability of the refrigerant composition.

[0036] If the content of the tetrafluoromethane is less than 10 weight%, the above effect is negligible, and if the content of the tetrafluoromethane exceeds 15 weight%, the above effect is not significantly improved, and the vapor pressure control balance is disrupted, causing the discharge pressure to rise rapidly, which can strain equipment such as compressors, and is undesirable because the global warming potential (GWP) increases excessively.

[0038] In one embodiment, the trifluoromethane is included in an amount of 5 to 10 weight% and is a halocarbon compound, commercially known as refrigerant R-23, exists as a liquid at -82.1°C or lower, and exhibits the effect of easily achieving an ultra-low temperature state as a refrigerant at temperatures below that.

[0039] Furthermore, it is chemically stable and highly non-reactive even at cryogenic temperatures, making it suitable as a laboratory and industrial refrigerant. It is applied to high-performance refrigerators (particularly ultra-low temperature refrigerators, e.g., helium coolers, medical MRI cooling, etc.) and enables cooling at temperatures much lower than other refrigerants. Since it is useful in situations requiring cooling below -80°C, the cryogenic refrigerant composition produced through this invention serves to facilitate easy application to existing refrigeration systems, such as cryogenic freezers and freeze dryers.

[0040] In addition, regarding thermal conductivity and pressure stability, the thermal conductivity is stable at low temperatures, and it has a high heat of vaporization, resulting in excellent cooling efficiency.

[0041] If the content of the above trifluoromethane is less than 5 weight%, the above effect is negligible, and if the content of the above trifluoromethane exceeds 10 weight%, the above effect is not significantly improved, and the vapor pressure of the ultra-low temperature refrigerant composition produced through the present invention is excessively increased, making pressure control difficult when designing containers or systems, and because the global warming potential (GWP) is very high (about 12,000 or more, which is thousands of times higher than CO2), it is undesirable because it can excessively reduce the eco-friendliness of the ultra-low temperature refrigerant composition produced through the present invention.

[0043] In one embodiment, the hexafluoroethane is included in an amount of 5 to 10 weight percent and is an inert gas of the perfluorocarbon (PFC) series, which is widely used for plasma etching / cleaning in semiconductor processes. It has a boiling point of about -78.2°C and is a gas at room temperature, but when liquefied, it can exist at a temperature much lower than dry ice, so it plays a role in imparting an ultra-low temperature generating effect to the ultra-low temperature refrigerant component.

[0044] Hexafluoroethane itself exhibits stable characteristics at cryogenic temperatures, thereby providing a cryogenic refrigerant composition that is easy to apply to existing cryogenic freezers and freeze dryers. It also has the advantage of being inert and chemically stable, making it easy to handle. With a boiling point of -78.2°C, it significantly enhances the low-temperature performance of the mixture, and when mixed with medium-boiling point components, it widens the temperature range, thereby enabling the provision of a refrigerant with excellent cryogenic performance.

[0045] In addition, the above hexafluoroethane has a high vapor pressure when used alone, but when used together with low boiling point components, it prevents the pressure from becoming excessively low, thereby creating a synergistic effect that ensures system operation stability.

[0046] In addition, since the above hexafluoroethane has a large molecular weight of 146 g / mol, it improves the fractionation stability of the ultra-low temperature refrigerant composition produced through the present invention and exhibits the effect of suppressing changes in the physical properties of the refrigerant composition.

[0047] If the content of the hexafluoroethane is less than 5 weight%, the above effect is negligible, and if the content of the hexafluoroethane exceeds 10 weight%, it is undesirable because not only is the content of 1,1,1-trifluoroethane, pentafluoroethane, tetrafluoromethane, trifluoromethane, and difluoromethane reduced excessively, but the vapor pressure in the system also goes beyond the control range and may cause an increase in discharge pressure.

[0049] In one embodiment, the difluoromethane is included in an amount of 4 to 9 weight percent and is commercially known as R-32. It is used as a refrigerant for high-efficiency air conditioners, and because it boils at about -52°C at atmospheric pressure, it rapidly absorbs ambient heat while vaporizing, thereby providing a strong local cooling effect.

[0050] In addition, when the above difluoromethane is mixed with 1,1,1-trifluoroethane, pentafluoroethane, tetrafluoromethane, etc., it has a high refrigeration capacity due to its high latent heat of vaporization characteristic of its molecular structure, thereby improving the refrigeration efficiency (COP); it prevents the drop in suction pressure caused by the inclusion of ultra-low temperature components; it imparts non-flammability performance; and it exhibits a synergistic effect that induces flattening of the refrigerant curve by continuously and smoothly connecting the temperature range of the refrigerant composition because it acts as an intermediate boiling point between the low boiling point component and the high boiling point component.

[0051] If the content of the difluoromethane is less than 4 weight%, the above effect is negligible, and if the content of the difluoromethane exceeds 9 weight%, the above effect is not significantly improved, and the content of 1,1,1-trifluoroethane, pentafluoroethane, tetrafluoromethane, trifluoromethane, and hexafluoroethane is excessively reduced, which is undesirable because it lowers the ultra-low temperature performance of the ultra-low temperature refrigerant composition and excessively reduces the content of low boiling point components, as well as increasing the design burden of the heat exchanger due to the increase in the operating pressure of the device.

[0053] In one embodiment, the ultra-low temperature refrigerant composition may further include argon and n-pentane, and it is preferable to include 0.1 to 1 weight% of argon and 0.1 to 1 weight% of n-pentane based on 100 weight% of the total composition.

[0054] As described above, when argon and n-pentane are included, the discharge pressure is lowered without excessively reducing the cryogenic generation effect of the cryogenic refrigerant composition, thereby reducing the load on the compressor and improving the refrigeration efficiency (COP), as well as ensuring the stability of the refrigerant circulation and the cooling device.

[0055] Generally, the range of discharge pressures required for ultra-low temperature mixed refrigerants is summarized and shown in Table 1 below.

[0056]

[0057]

[0059] As shown in Table 1 above, the appropriate discharge pressure required varies depending on the target condensation temperature of the refrigerant composition. Since exceeding the appropriate discharge pressure can strain the refrigeration system, it is desirable to adjust the discharge pressure.

[0060] The generally required discharge pressure range refers to the range from the allowable minimum to maximum pressure of the refrigerant gas discharged from the compressor, and is set based on the condenser design pressure and the compressor safety margin.

[0061] The above argon (Ar) is included in an amount of 0.1 to 1 weight% and is an inert gas with low chemical reactivity and high safety, but has a low specific heat (heat capacity) so it cannot store much heat, but can induce rapid temperature changes, and has a boiling point of less than -185.8℃, so when liquefied, it acts as a cryogenic refrigerant.

[0062] In addition, the argon not only serves to regulate the temperature gradient of each refrigerant constituting the ultra-low temperature refrigerant composition according to the present invention, but also provides smooth lubricity, thereby making it easier to apply to existing refrigeration systems such as ultra-low temperature freezers and freeze dryers.

[0063] In other words, since argon has a cryogenic boiling point, its inclusion in a refrigerant composition lowers the average saturation pressure; it also reduces the average molecular weight of the refrigerant composition, thereby decreasing the pressure contribution at the same temperature; and because it consists of monatomic components that reduce vapor density, it stabilizes the discharge pressure of the compressor, thereby imparting the effect of lowering the discharge pressure to the cryogenic refrigerant composition manufactured through this invention.

[0064] If the argon content is less than 0.1 weight%, the above effect is negligible, and if the argon content exceeds 1 weight%, the above effect is not significantly improved, and the pressure of the ultra-low temperature refrigerant composition may increase excessively, which is undesirable.

[0065] In addition, the above n-pentane is included in an amount of 0.1 to 1 weight% and can produce a localized rapid cooling effect as it absorbs a large amount of heat when evaporating from liquid to gas. However, compared to general refrigerants (R-134a, R-410A, etc.), it has a higher boiling point and is not suitable as a cryogenic refrigerant on its own. Nevertheless, it is mainly used as a blend or secondary refrigerant in cryogenic media by utilizing its property of being cryogenic to below -100°C. In the present invention, it is added to a cryogenic refrigerant composition to widen the boiling point range and improve heat exchange efficiency, and plays a role in ensuring fluidity by preventing solidification.

[0066] The above n-pentane has a boiling point of 36°C, which is much higher than other ultra-low temperature refrigerants, and its molecular structure consists of a short-chain alkane structure, which is non-polar and contributes to low pressure. It also exhibits a high boiling point, which lowers the pressure on the condenser side, and consequently has the effect of reducing the discharge pressure of the compressor.

[0067] If the content of n-pentane is less than 0.1 weight%, the above effect is negligible, and if the content of n-pentane exceeds 1 weight%, the above effect is not significantly improved, and the flammability of n-pentane is excessively imparted, which increases the risk of explosion and the global warming potential, so it is undesirable.

[0068] Hereinafter, the method for manufacturing a cryogenic refrigerant composition according to the present invention and the physical properties of the cryogenic refrigerant composition manufactured by said method will be explained with reference to examples.

[0070] <Example 1>

[0071] A refrigerant composition for ultra-low temperatures was prepared by mixing 34 wt% of 1,1,1-trifluoroethane, 34 wt% of pentafluoroethane, 11.5 wt% of tetrafluoromethane, 7 wt% of trifluoromethane, 7 wt% of hexafluoroethane, and 6.5 wt% of difluoromethane.

[0073] <Example 2>

[0074] A refrigerant composition for ultra-low temperatures was prepared by mixing 30 wt% of 1,1,1-trifluoroethane, 30 wt% of pentafluoroethane, 15 wt% of tetrafluoromethane, 10 wt% of trifluoromethane, 10 wt% of hexafluoroethane, and 5 wt% of difluoromethane.

[0076] <Example 3>

[0077] A refrigerant composition for ultra-low temperatures was prepared by mixing 40 wt% of 1,1,1-trifluoroethane, 36 wt% of pentafluoroethane, 10 wt% of tetrafluoromethane, 5 wt% of trifluoromethane, 5 wt% of hexafluoroethane, and 4 wt% of difluoromethane.

[0079] <Example 4>

[0080] A refrigerant composition for ultra-low temperature was prepared by mixing 33.5 wt% of 1,1,1-trifluoroethane, 33.5 wt% of pentafluoroethane, 11.5 wt% of tetrafluoromethane, 7 wt% of trifluoromethane, 7 wt% of hexafluoroethane, 6.5 wt% of difluoromethane, 0.5 wt% of argon, and 0.5 wt% of n-pentane.

[0082] <Example 5>

[0083] A refrigerant composition for ultra-low temperature was prepared by mixing 30 wt% of 1,1,1-trifluoroethane, 30 wt% of pentafluoroethane, 15 wt% of tetrafluoromethane, 10 wt% of trifluoromethane, 10 wt% of hexafluoroethane, 4 wt% of difluoromethane, 0.5 wt% of argon, and 0.5 wt% of n-pentane.

[0085] <Example 6>

[0086] A refrigerant composition for ultra-low temperatures was prepared by mixing 40 wt% of 1,1,1-trifluoroethane, 35 wt% of pentafluoroethane, 10 wt% of tetrafluoromethane, 5 wt% of trifluoromethane, 5 wt% of hexafluoroethane, 4 wt% of difluoromethane, 0.5 wt% of argon, and 0.5 wt% of n-pentane.

[0088] <Comparative Example 1>

[0089] A refrigerant composition was prepared by mixing 29 wt% of 1,1,1-trifluoroethane, 28 wt% of pentafluoroethane, 16 wt% of tetrafluoromethane, 11 wt% of trifluoromethane, 11 wt% of hexafluoroethane, and 5 wt% of difluoromethane.

[0091] <Comparative Example 2>

[0092] A refrigerant composition was prepared by mixing 41 wt% of 1,1,1-trifluoroethane, 41 wt% of pentafluoroethane, 9 wt% of tetrafluoromethane, 4 wt% of trifluoromethane, 4 wt% of hexafluoroethane, and 1 wt% of difluoromethane.

[0094] <Comparative Example 3>

[0095] A refrigerant composition for ultra-low temperatures was prepared by mixing 34 wt% of 1,1,1-trifluoroethane, 34 wt% of pentafluoroethane, 11.5 wt% of tetrafluoromethane, 7 wt% of trifluoromethane, 7 wt% of hexafluoroethane, 6 wt% of difluoromethane, and 0.5 wt% of argon.

[0097] <Comparative Example 4>

[0098] A refrigerant composition for ultra-low temperatures was prepared by mixing 34 wt% of 1,1,1-trifluoroethane, 34 wt% of pentafluoroethane, 11.5 wt% of tetrafluoromethane, 7 wt% of trifluoromethane, 7 wt% of hexafluoroethane, 6 wt% of difluoromethane, and 0.5 wt% of n-pentane.

[0100] <Comparative Example 5>

[0101] A refrigerant composition for ultra-low temperatures was prepared by mixing 33.99 wt% of 1,1,1-trifluoroethane, 33.99 wt% of pentafluoroethane, 11.5 wt% of tetrafluoromethane, 7 wt% of trifluoromethane, 7 wt% of hexafluoroethane, 6.5 wt% of difluoromethane, 0.01 wt% of argon, and 0.01 wt% of n-pentane.

[0103] <Experimental Example 1> Comparison of Low-Temperature Generation Effects of Refrigerant Compositions

[0104] The low-temperature generation effect of the refrigerant compositions prepared through Examples 1 to 6 and Comparative Examples 1 to 2 above was measured and is shown in Table 2 below. The low-temperature generation effect was measured by using a method of measuring the temperature around the evaporator when operating a refrigeration system for an ultra-low temperature freezer and freeze dryer using each of the prepared ultra-low temperature refrigerant compositions. In addition, the measurement was taken after setting the operating time of the refrigeration system for the ultra-low temperature freezer and freeze dryer to 60 minutes.

[0105] Table 2

[0106]

[0108] As a result, Examples 1 to 6 of the present invention achieved a superior ultra-low temperature generation effect compared to Comparative Examples 1 and 2. This was determined to be because the six types of refrigerant components were mixed in an optimal ratio within a specific weight ratio range, thereby forming a unique synergy that maintains refrigeration capacity in the cryogenic range and smoothly connects the evaporation-condensation curves.

[0109] On the other hand, comparative examples in which the component ratios deviated slightly from the critical range of the claim showed distinct limitations in the ultra-low temperature generation indicator. Specifically, in the case of Comparative Example 2, where the content of high-boiling point components 1,1,1-trifluoroethane and pentafluoroethane exceeded the upper limit (40%) by only 1% (41%), and key ultra-low temperature inducing components such as tetrafluoromethane (9%), trifluoromethane (4%), and hexafluoroethane (4%) fell short of the lower limit by 1-2%, the ultra-low temperature generation effect was found to have decreased rapidly. This was determined to be because the temperature bridge function of the entire mixed refrigerant collapsed, failing to reach the target ultra-low temperature (-80℃ or lower), even though the high-boiling point components only slightly exceeded the boundary value and the low-boiling point components were only slightly lacking.

[0110] From this, it was confirmed that the numerically limited mixing ratio of the six types of refrigerant components of the present invention is a critical configuration for maximizing ultra-low temperature generation efficiency.

[0112] <Experimental Example 2> Comparison of Discharge Pressures of Refrigerant Compositions

[0113] In addition, the discharge pressure of the ultra-low temperature refrigerant compositions prepared through Examples 1 to 6 and Comparative Examples 1 to 5 was measured and is shown in Table 3 below. However, the discharge pressure was measured using a refrigeration compressor manufactured by Danfoss, a method of charging and operating the refrigerant composition prepared by a conventional method and measuring the discharge pressure of the compressor.

[0114] Table 3

[0115]

[0117] As a result, Examples 1 to 6 demonstrated stability by maintaining an appropriate discharge pressure without straining the refrigeration system, and in particular, Examples 4 to 6, which additionally included argon and n-pentane, achieved an excellent effect of further lowering the discharge pressure. This was determined to be because the intermediate boiling point components balanced the suction pressure and discharge pressure, and the additives argon and n-pentane acted as buffers that reduced the average molecular weight and vapor density and lowered the pressure on the condenser side, thereby forming a unique synergy that significantly reduced the compressor load.

[0118] On the other hand, Comparative Example 1 showed a result where the discharge pressure surged beyond the allowable range. This was determined to be because the balance of vapor pressure control of the entire refrigerant was disrupted by the fact that the content of low-boiling point components (tetrafluoromethane 16%, trifluoromethane 11%, hexafluoroethane 11%) exceeded the critical upper limit by only 1%, thereby increasing the design burden on the compressor and heat exchanger and causing fatal strain.

[0119] In addition, Comparative Examples 3 to 5, which contained only a portion of the additives argon or n-pentane or only trace amounts below the lower limit (0.01%), showed a negligible effect in reducing discharge pressure. From this, it was confirmed that strict numerical limitations on the refrigerant base components and the specific ratio blending of additives (argon, n-pentane) are essential synergistic compositions for relieving compressor load and ensuring system operation stability.

[0121] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

Claim 1 A cryogenic refrigerant composition characterized by comprising 1,1,1-trifluoroethane, pentafluoroethane, tetrafluoromethane, trifluoromethane, hexafluoroethane, and difluoromethane, wherein the cryogenic refrigerant composition comprises, based on 100 weight% of the total composition, 30 to 40 weight% of 1,1,1-trifluoroethane, 30 to 40 weight% of pentafluoroethane, 10 to 15 weight% of tetrafluoromethane, 5 to 10 weight% of trifluoromethane, 5 to 10 weight% of hexafluoroethane, and 4 to 9 weight% of difluoromethane. Claim 2 delete Claim 3 A cryogenic refrigerant composition according to claim 1, characterized in that the cryogenic refrigerant composition further comprises 0.1 to 1 weight% of argon and 0.1 to 1 weight% of n-pentane based on 100 weight% of the total composition.

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