【Mechanical Equipment Technology Edition】Daily Question 20171218: Refrigerants

(1) Inorganic compounds. Water, ammonia, carbon dioxide, etc. (2) Derivatives of saturated hydrocarbons, commonly known as Freons. They are mainly derivatives of methane and ethane. Such as R12, R22, R134a, etc. (3) Saturated hydrocarbons. Such as propane, isobutane, etc. (4) Unsaturated hydrocarbons. Such as ethylene, propylene, etc. (5) Azeotropic mixed refrigerants. Such as R502, etc. (6) Azeotrope-free mixed refrigerants. Such as R407c, R410, etc.

R134a R22 Ammonia

Refrigerants widely used in compression refrigeration systems are ammonia, Freons, and hydrocarbons. Based on their chemical composition, refrigerants can be divided into five categories: inorganic compound refrigerants, Freons, saturated hydrocarbon refrigerants, unsaturated hydrocarbon refrigerants, and azeotropic mixture refrigerants. Based on the condensation pressure, refrigerants can be divided into three categories: high-temperature (low-pressure) refrigerants, medium-temperature (medium-pressure) refrigerants, and low-temperature (high-pressure) refrigerants. Commonly used Freon refrigerants include R12, R22, R502, and R1341a, as other types of refrigerants have now been discontinued or banned. No explanation is given here. Freon 12 (CF2Cl2, R12): It is one of the most commonly used fluorine-based refrigerants, and is widely employed in medium and small-sized food storage facilities, household refrigerators, as well as in cooling systems for water and road transport. R12 has good thermodynamic properties, with a low refrigeration pressure; the pressure using air cooling or natural condensation is approximately 0.8–1.2 KPa. The standard evaporation temperature of R12 is -29°C; it is a medium-temperature refrigerant. When used in medium and small piston compressors, it can achieve low temperatures of -70°C. Large centrifugal compressors can achieve a low temperature of -80°C. In recent years, R134a has become the replacement refrigerant for refrigerators. Freon 22 (CHF2Cl, R22): It is one of the most widely used fluorine-based refrigerants, primarily employed in household air conditioners and low-temperature refrigerators. The thermodynamic properties of R22 are similar to those of ammonia. The standard vaporization temperature is -40.8°C, and the condensation pressure is usually no more than 1.6 MPa. R22 is non-flammable and non-explosive, making it safer and more reliable than ammonia in use. The specific capacity of R22 is about 60% higher than that of R12; its cooling capacity per unit volume and saturated pressure at low temperatures are both higher than those of R12 and ammonia. In recent years, R134a has been widely used as a substitute for refrigerants in large air-conditioning chillers. Freon 502 (R502): R502 is an azeotropic mixture composed of R12 and R22 in proportions of 51.2% and 48.8%, respectively. Compared to R115 and R22, R502 has better thermodynamic properties and is more suitable for low temperatures. The standard evaporation temperature of R502 is -45.6°C, and its normal operating pressure is similar to that of R22. Under the same operating conditions, its cooling capacity per unit volume is higher than that of R22, but its exhaust temperature is lower than that of R22. R502 is used in fully enclosed, semi-enclosed, or certain medium and small refrigeration units, with an evaporation temperature that can go as low as -55°C. R502 is widely used in refrigerators. Freon 134a (C2H2F4, R134a): It is a relatively new type of refrigerant, with an evaporation temperature of -26.5°C. Its main thermodynamic properties are similar to those of R12; it does not destroy the ozone layer in the atmosphere, and it is an environmentally friendly refrigerant that has been promoted in recent years, but it does cause the greenhouse effect. It is a relatively ideal R12 replacement refrigerant. Environmentally friendly refrigerants generally include the following types: ※ R-134a (tetrafluoroethane) refrigerant. R134a is one of the main refrigerants recognized internationally as a substitute for R12; it is commonly used in vehicle air conditioning systems, as well as in commercial and industrial cooling systems. It can also be used as a blowing agent in the production of rigid plastic insulation materials, and it is utilized in the formulation of other mixed refrigerants such as R404A and R407C. Primary use: It primarily replaces R12 as a refrigerant, and is widely used in car air conditioning and refrigerator cooling. Product packaging: Cylinder packaging, 13.6 kg/cylinder, 400 kg/cylinder, 1000 kg/cylinder, ISO TANK. ※ Physical and chemical properties of R-410A refrigerant: Under normal temperature and pressure, R410A is a chlorine-free fluorinated alkane azeotropic mixed refrigerant; it is a colorless gas that exists as a compressed liquid when stored in steel cylinders. Its ODP is 0, so R410A is an environmentally friendly refrigerant that does not damage the ozone layer in the atmosphere. Primary uses: R410A is mainly used as a substitute for R22 and R502. It features cleanliness, low toxicity, non-flammability, and excellent cooling performance, and is widely used in household air conditioners, small commercial air conditioners, and residential central air conditioning systems. Product packaging: Cylinder packaging, 11.3 kg/cylinder, 400 kg/cylinder, 1000 kg/cylinder, ISO TANK. ※ Physical and chemical properties of R-407C refrigerant: Under normal temperature and pressure, R407C is a chlorine-free fluorinated alkane azeotropic mixed refrigerant; it is a colorless gas that exists as a compressed liquid when stored in steel cylinders. Its ODP is 0, so R407C is an environmentally friendly refrigerant that does not damage the atmospheric ozone layer. Primary uses: R407C is primarily used as a substitute for R22; it features cleanliness, low toxicity, non-flammability, and excellent cooling performance, and is widely used in household air conditioners as well as small and medium-sized central air conditioning systems. Product packaging: Cylinder packaging, 11.3 kg/cylinder, 400 kg/cylinder, 1000 kg/cylinder, ISO TANK. ※ Physical and chemical properties of R417A refrigerant: Under normal temperature and pressure, R417A is a chlorine-free fluorinated alkane azeotropic mixed refrigerant; it is a colorless gas that exists as a compressed liquefied state when stored in steel cylinders. Its ODP is 0, so R417A is an environmentally friendly refrigerant that does not damage the ozone layer in the atmosphere. Primary uses: R417A is primarily used as a substitute for R22; it features cleanliness, low toxicity, non-flammability, and excellent cooling performance. It is used in heat pumps (for original equipment manufacturing as a replacement for R22) and air conditioners (for after-sales replacement of R22). Product packaging: Cylinders, 11.3 kg/cylinder, 400 kg/cylinder, 1000 kg/cylinder. ISO containers or transport tanks can also be provided upon the customer’s request ； Packaged goods category 2.2. ※ Physical and chemical properties of R-404A refrigerant: R404A shall not be a chlorine-free azeotropic mixed refrigerant; it is a colorless gas at normal temperature and pressure, and exists as a compressed liquefied gas when stored in steel cylinders. Its ODP is 0, so R404A is an environmentally friendly refrigerant that does not damage the ozone layer in the atmosphere. Primary uses: R404A is mainly used as a substitute for R22 and R502; it features cleanliness, low toxicity, non-flammability, and excellent cooling performance, and is widely used in medium- and low-temperature refrigeration systems. Product packaging: Cylinders, 10.9 kg/cylinder, 1000 kg/cylinder. ※ Physical and chemical properties of refrigerant R-507: R507 is a chlorine-free azeotropic mixed refrigerant that is a colorless gas at normal temperature and pressure; it exists as a compressed liquefied gas when stored in steel cylinders. Its ODP is 0, so R507 is an environmentally friendly refrigerant that does not damage the atmospheric ozone layer. Primary uses: R507 is mainly used as a substitute for R22 and R502. It features cleanliness, low toxicity, non-flammability, and excellent cooling performance, and is widely used in medium- and low-temperature refrigeration systems. Product packaging: Cylinders, 11.3 kg/cylinder, 400 kg/cylinder. ※ R-23 (trifluoromethane) refrigerant – Physical and chemical properties: R23 (trifluoromethane, FREON 23) has a boiling point of -82.1°C at standard pressure, a freezing point of -155.2°C. Its liquid density at 25°C is 0.67 kg/L, the critical density is 0.525 kg/L, and the critical pressure is 4.83 MPa. Its ozone depletion potential (ODP) is 0, making it an environmentally friendly refrigerant. Primary use: Trifluoromethane, also known as HFC-23, is a high-pressure liquefied gas that can be used as a refrigerant to replace CFC-13. It is also an ideal substitute for Halon 1301, featuring cleanliness, low toxicity, and excellent fire-extinguishing performance. Product packaging: packaged in high-pressure cylinders, 9.08 kg/cylinder, 30 kg/cylinder. ※ Physical and chemical properties of R-508A refrigerant: R508A is a chlorine-free azeotropic mixed refrigerant; it is a colorless gas at normal temperature and pressure, and exists as a compressed liquefied gas when stored in steel cylinders. Its ODP is 0, so R508A is an environmentally friendly refrigerant that does not damage the atmospheric ozone layer. Primary uses: R508A is primarily used as a substitute for R13, R23, and R503. It features cleanliness, low toxicity, non-flammability, and excellent cooling performance, and is widely used in ultra-low temperature freezing systems, such as those for medical refrigeration and scientific research. Product packaging: packaged in high-pressure cylinders, 5 kg/cylinder, 9.08 kg/cylinder. ※ Physical and chemical properties of R-508B refrigerant: R508B is a chlorine-free azeotropic mixed refrigerant that is a colorless gas at normal temperature and pressure; it exists as a compressed liquefied gas when stored in steel cylinders. Its ODP is 0, so R508B is an environmentally friendly refrigerant that does not damage the atmospheric ozone layer. Primary uses: R508B is primarily used as a substitute for R13, R23, and R503. It features cleanliness, low toxicity, non-flammability, and excellent cooling performance, and is widely used in ultra-low temperature freezing systems, such as those for medical refrigeration and scientific research. Product packaging: packaged in high-pressure cylinders, 5 kg/cylinder, 9.08 kg/cylinder. ※ R-152a (difluoroethane) refrigerant – Physical and chemical properties: HFC-152a (1,1-difluoroethane, CH3CHF2), molecular weight 66.1, boiling point -24.7°C, critical temperature 113.5°C, critical pressure 4.58 MPa; it is a flammable liquefied gas with an ozone depletion potential (ODP) of 0. Primary uses: It is mainly used as a refrigerant, foam agent, aerosol propellant, and cleaning agent, and it is also an important component in mixed refrigerants. Product packaging: Cylinder packaging, 10 kg/cylinder, 640 kg/cylinder,

There are several types of refrigerants: 1. Refrigerants used in the early days: Year, Type, Chemical formula: 1830s, Rubber sulfides, Diethyl ether (ethyl ether), CH3-CH2-O-CH2-CH3; 1840s, Methyl ethyl ether (R-E170), CH3-O-CH3; 1850, Water/sulfuric acid, H2O/H2SO4; 1856, Alcohol, CH3-CH2-OH; 1859, Ammonia/water, NH3/H2O; 1866, Crude gasoline, Carbon dioxide (R744), CO2; 1860s, Ammonia (R717), NH3; Methylamine (R630), CH3(NH2); Ethylamine (R631), CH3-CH2(NH2); 1870, Methylate (R611), HCOOCH3; 1875, Sulfur dioxide (R764), SO2; 1878, Methyl chloride, chloromethane (R40), CH3CI; 1870s, Chloroethane (R160), CH3-CH2CI; 1891, Sulfuric acid and hydrocarbons, H2SO4, C4H10, C5H12, (CH3)2CH-CH3; 20th century, Bromoethane (R160B1), CH3-CH2Br; 1912, Carbon tetrachloride, CCl4; Water vapor (R718), H2O; 1920s, Isobutane (R600a), (CH3)2CH-CH3; Propane (R290), CH3-CH2-CH3; 1922, Dichloroethane isomers (R1130), CH2Cl=CHCl; 1923, Gasoline, HCs; 1925, Trichloroethane (R1120), CH2Cl=CCl2; 1926, Dichloromethane (R30), CH2Cl2. 2. Refrigerants developed in the second phase: Year, Refrigerant: 1931, R12; 1932, R11; 1933, R114; 1934, R113; 1936, R22; 1945, R13; 1955, R14; 1961, R502. 3. Azeotropic refrigerants began to be used starting in the 1960s. In the refrigerant numbering standard, aoccomodating codes have not yet been assigned to azeotropic refrigerants; instead, the numbering sequence starting with 400 after R is reserved for adding new codes. Such as: R400, R401, R402, … R411; named according to the Montreal Protocol to distinguish the degree of damage caused by these fluorocarbons to the atmospheric ozone layer. CFCs (Chlorofluorocarbons): Contain no hydrogen; are pollutants that severely damage the ozone layer and are therefore banned. Examples include CF2Cl2 ——R12———CFC12, CFCl3 ——R11———CFC11. HCFCs (Hydrochlorofluorocarbons): Contain hydrogen; are less harmful pollutants and considered transitional substances. Examples include CHF2Cl——R22———HCFC22. HFCs (Hydrofluorocarbons): Contain no chlorine and cause no environmental harm; they are used as alternatives but still require further research and development. Examples include C2H2F4——R134a——HFC134a

Inorganic compound refrigerants, Freons, saturated hydrocarbon refrigerants, unsaturated hydrocarbon refrigerants, and azeotropic mixture refrigerants. R12 refrigerant, R134a refrigerant, R410A refrigerant, 4, R404A refrigerant, 5, R600a refrigerant, R22 refrigerant,

Refrigerants widely used in compression refrigeration systems are ammonia, Freons, and hydrocarbons. Based on their chemical composition, refrigerants can be divided into five categories: inorganic compound refrigerants, Freons, saturated hydrocarbon refrigerants, unsaturated hydrocarbon refrigerants, and azeotropic mixture refrigerants. Based on the condensation pressure, refrigerants can be divided into three categories: high-temperature (low-pressure) refrigerants, medium-temperature (medium-pressure) refrigerants, and low-temperature (high-pressure) refrigerants. Commonly used Freon refrigerants include R12, R22, R502, and R1341a, as other types of refrigerants have now been discontinued or banned. Freon 12 (CF2Cl2, R12): It is one of the most commonly used fluorine-based refrigerants, and is widely employed in medium and small-sized food storage facilities, household refrigerators, as well as in cooling systems for water and road transport. Freon 22 (CHF2Cl, R22): It is one of the most widely used fluorine-based refrigerants, primarily employed in household air conditioners and low-temperature refrigerators. Freon 502 (R502): R502 is an azeotropic mixture composed of R12 and R22 in proportions of 51.2% and 48.8%, respectively. Freon 134a (C2H2F4, R134a): It is a relatively new type of refrigerant, with an evaporation temperature of -26.5°C.

Hydrocarbon refrigerants such as methane, ethane, and ethylene； Azeotropic refrigerant ； ammonia ； Freon

R12, R22, R134A, R123, R407C, R410A, R600a, R32, ammonia, etc