JP2006124462A - Refrigerant composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe and non-toxic refrigerant composition free from the ozonosphere destruction problem and having extremely small global warming coefficient and excellent performance by mixing propane, n-butane and isobutane. <P>SOLUTION: The refrigerant composition for a freezing machine contains 40-70 wt.% propane, 10-40 wt.% n-butane and 5-30 wt.% isobutane based on the total weight of propane, n-butane and isobutane. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigerant composition containing propane, n-butane and isobutane, which is used in car air conditioners, commercial / household air conditioners, and gas heat pumps (GHP) / electrical heat pumps (EHP).

  Until now, chlorofluorocarbon (CFC fluorocarbon, HCFC hydrofluorocarbon) has an excellent refrigerant capacity and has been widely used as a refrigerant for refrigerators and air conditioners all over the world. However, since CFCs contain chlorine and destroy the ozone layer, the production of CFCs out of specific CFCs was abolished in 1996 in Japan and Europe and America. The same specific chlorofluorocarbon, HCFC (Hydrofluorofluorocarbon), will be regulated in sequence since 2004, and will be completely abolished by 2010 in Europe and by 2020 in other developed countries.

  In addition, alternative chlorofluorocarbon (HFC hydrofluorocarbon, PFC, SP6), which replaces the above-mentioned specific chlorofluorocarbon, has zero ozone depletion coefficient, low toxicity, non-combustibility, satisfactory characteristics and performance, but is incompatible with mineral oil and lubricity. It has a problem of deterioration. In particular, this alternative chlorofluorocarbon does not destroy the ozone layer but has a very high global warming potential.Therefore, although there is no specific regulation and it is left to the voluntary action of the industry, its use will be abolished in the near future. It will be greatly regulated.

  Recently developed natural refrigerants such as carbon dioxide, ammonia, water, and air also have features of zero ozone depletion coefficient and almost zero global warming coefficient, but safety, performance, convenience, etc. There are difficulties. That is, carbon dioxide is incombustible and has low toxicity, but has low efficiency and ultrahigh pressure (12 MPa). Ammonia is as efficient as HFC, but has toxicity, irritating odor, and incompatibility with copper. Water and air are non-combustible and non-toxic, but very low efficiency.

  An object of the present invention is to provide a refrigerant composition that has no risk of ozone layer destruction, has a small adverse effect on global warming, and has no toxicity.

  The present invention is characterized by containing 40 to 70% by weight of propane, 10 to 40% by weight of n-butane, and 5 to 30% by weight of isobutane based on the total weight of propane, n-butane and isobutane. The present invention relates to a refrigerant composition for a refrigerator. Thereby, the ozone layer is not destroyed, the global warming potential is extremely small (GWP is about 3), there is no toxicity, and the refrigerant | coolant which has the outstanding cooling capability can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The principle of the cooling system is based on the continuous heat exchange between the surrounding medium and the latent heat that takes heat energy from the surrounding medium when the substance (refrigerant) is vaporized. Further, since the evaporation temperature of the refrigerant depends on the pressure, if the pressure is lowered, the evaporation temperature also decreases, so that a lower temperature can be obtained.

  On the other hand, the principle of the heating / hot water supply system is achieved by continuous heat exchange with water, air, or the like because it takes heat from the surroundings by evaporation of the refrigerant and becomes a compressed high-temperature gas.

The cooling / heating / hot water supply system based on the principle of the cooling / heating system includes a compressor, a condenser, an expansion valve, an evaporator, and these devices as a system that can perform a continuous process from evaporation of refrigerant to compression. This is a cycle (cooling-heating reference cycle) system composed of pipes through which refrigerant circulates. A non-limiting example of this cycle system is shown in FIG. The role of these devices is shown below.
-EQ1 compressor: The cold refrigerant turned into a gas in the evaporator is sucked and compressed into a high-temperature and high-pressure gas.
-EQ2 condenser: The high-temperature high-pressure gaseous medium discharged from the compressor is cooled and condensed with water or air (outside air) to form a liquid (for heating / hot water supply).
-EQ3 expansion valve: A high-temperature and high-pressure liquid refrigerant is expanded into a low-temperature and low-pressure refrigerant.
-EQ4 evaporator: A low-temperature and low-pressure refrigerant is brought into contact with the surrounding gas at the outlet of the expansion valve, and the heat is removed to evaporate and vaporize the gas (for cooling).

  In order to actually evaluate the cooling / heating / hot-water supply capacity of the refrigerant, the above-mentioned reference cycle is numerically modeled, and a known method (for example, “non-azeotropic mixing” by Miyara et al. Is used by using a general-purpose numerical chemical process simulator. The effect of heat transfer characteristics of the heat exchanger on the performance of the refrigerant heat pump cycle is analyzed and evaluated according to the Japan Refrigeration Association Proceedings Vol. 7, No. 1, pages 65-73, 1990, etc.) be able to. A general-purpose numerical chemical process simulator has a built-in database of thermodynamic properties of various components, and performs equilibrium thermodynamic calculations between chemical components corresponding to the mechanical engineering functions of various systems.

  In the numerical simulation, the systems constituting the compressor, the circulator, the expansion valve, and the evaporator in which the refrigerant circulates are digitized, and the compressor outlet pressure (P1), the condenser outlet temperature (T2), and the evaporator temperature (T3). The cooling / heating / hot water supply capacity is evaluated as a coefficient of performance (COP) using the concentration of the refrigerant composition component as a parameter.

Coefficient of performance of cooling = total absorbed heat in the evaporator of the cooling ÷ compressor power factor Coefficient of performance of heating / hot water = total amount of exhaust heat in the condenser of the refrigerant ÷ compressor power

  Refrigerators that can suitably use the refrigerant composition of the present invention include, but are not limited to, car air conditioners, commercial / household air conditioners, gas heat pumps (GHP), and electrical heat pumps (EHP). In addition, the refrigerant composition of the present invention can be used as it is in principle for car air conditioners, commercial / home air conditioners, GHP / EHP, etc. in which existing refrigerants such as R22 are used. However, in view of the physical properties of the refrigerant composition of the present invention, it is further desirable to improve and design the mechanical surfaces such as the condenser and the piston so as to be adapted to the refrigerant composition of the present invention.

(Example)
Hereinafter, the content of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

  In order to evaluate the refrigerant characteristics of the propane / n-butane / isobutane ternary refrigerant composition, the refrigerant capacity was simulated based on the refrigerant circulation system of FIG. The system is a cooling cycle consisting of a compressor, a condenser, an expansion valve and an evaporator. The simulation was performed by the following procedure using a numerical chemical process simulator.

Simulation Procedure The state quantities on each line (1 to 4) in the cycle of FIG. 1 are calculated to determine the coefficient of performance (COP) related to cooling of the system.

COP is the ratio of the drive energy of the compressor to the endothermic energy at EQ4.
Calculation conditions: The following amount is given as a constant.
T2 (condenser outlet temperature) = 38 ° C. or 35 ° C.
T3 / T4 = about 2 ° C (set so that the intermediate value between T3 and T4 is about 2 ° C)
P3 (Expansion valve outlet pressure)
P1 (compressor outlet pressure) was taken as a variable parameter.

  Using the simulator described above, COPs were obtained for the propane / n-butane / isobutane ternary mixed refrigerant composition and, for comparison, propane alone as follows.

  In the system of FIG. 1, a simulation was performed for a refrigerant composition of 55 wt% propane, 31.5 wt% n-butane, and 13.5 wt% isobutane with an expansion valve outlet pressure (P3) = 0.27 MPa. Here, when the compressor outlet pressure (P1) is 0.92 MPa and the condenser outlet temperature (T2) is 38 ° C. (experiment number 1), the compressor outlet pressure is 0.85 MPa and the condenser outlet temperature is 35. The COP was calculated for the case of 0 ° C. (Experiment No. 2). The obtained results are shown in Table 1.

  In the same system, a simulation was performed for a refrigerant composition of 50% by weight of propane, 38% by weight of n-butane, and 12% by weight of isobutane with an expansion valve outlet pressure = 0.25 MPa. Here, when the compressor outlet pressure is 0.87 MPa and the condenser outlet temperature is 38 ° C. (experiment number 3), and when the compressor outlet pressure is 0.80 MPa and the condenser outlet temperature is 35 ° C. (experiment The COP was calculated for number 4). The obtained results are shown in Table 1.

  In the same system, a simulation was performed for a refrigerant composition of 60% by weight of propane, 14% by weight of n-butane and 26% by weight of isobutane with an expansion valve outlet pressure = 0.30 MPa. Here, when the compressor outlet pressure is 0.99 MPa and the condenser outlet temperature is 38 ° C. (experiment number 5), and when the compressor outlet pressure is 0.91 MPa and the condenser outlet temperature is 35 ° C. (experiment The COP was calculated for number 6). The obtained results are shown in Table 1.

(Comparative Example 1)
In the same system, simulation was performed for a refrigerant composition of 100% by weight of propane, with an expansion valve outlet pressure = 0.50 MPa. Here, when the compressor outlet pressure is 1.3 MPa, the condenser outlet temperature is 38 ° C. (experiment number 7), and when the compressor outlet pressure is 1.3 MPa and the condenser outlet temperature is 35 ° C. (experiment) The COP was calculated for number 8). The obtained results are shown in Table 1.

  As is clear from Table 1, in Examples 1 to 3, the refrigerant composition exhibits a high COP at a lower compressor pressure than that of propane alone, and has a good cooling effect (evaporator outlet temperature is 10 ° C. or lower). It can be seen that

  From the above results, the refrigerant composition of the present invention is used as a refrigerant for industrial / industrial air conditioners (heat pumps) and refrigerators in a system that operates at a condenser outlet temperature of 35 ° C. or less, and alleviates the heat island phenomenon. It is expected to be used as a refrigerant for cogeneration using geothermal heat. In particular, the refrigerant composition of the present invention is expected to be used as a refrigerant for car air conditioners and household air conditioners because it has a global warming potential of almost zero and is a safe substance without toxicity.

Propane / n-butane / isobutane ternary mixed refrigerant cycle system.

Claims (3)

  For a refrigerator characterized by containing 40 to 70% by weight of propane, 10 to 40% by weight of n-butane and 5 to 30% by weight of isobutane based on the total weight of propane, n-butane and isobutane Refrigerant composition.   A refrigerant composition containing 40 to 70% by weight propane, 10 to 40% by weight n-butane and 5 to 30% by weight isobutane based on the total weight of propane, n-butane and isobutane is used in the refrigerator. how to.   The method according to claim 2, wherein the refrigerator is a car air conditioner.

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