In terms of its properties, it should be considered a highclass refrigerant. The flood of the airconditioner, that is, the refrigerants, their properties, merits and demerits are summarized to map the various types and their classifications. Cfcs are generally characterised by a big odp value, because they contain chlorine, which is accused of heavily contributing to the ozone. Understanding refrigerant oils by alec johnson oct, 2017 something that can be confusing to a lot of technicians rather they are a residential tech, commercial tech, or a mechanic is refrigerant. Compressor has to be operated at high vacuum if the boiling point of the refrigerant is high at atmospheric pressure. The 2015 fgas regulation is driving industry to use lower gwp1 refrigerants in. These physical properties of refrigerants help us select the proper refrigerant for the application as per our requirement. In spite of that, we can state certain desirable properties that a refrigerant. From this viewpoint, ammonia and water are ideally suited, but their low thermodynamic and chemical properties restrict their use in all types of refrigeration systems. Characteristics of refrigerants pure r12 cc 1425f425. The term freon is a common descriptor or proprietary eponym similar to a generic trademark like xerox or kleenex. The most common types of refrigerants in use nowadays are presented below.
What are the most common types of refrigerant today. Carbon dioxide is widely used as a refrigerant in mechanical systems refrigerant, marine services, hospitals, etc. The extensive variety of utilization of the refrigerant is because of its safe properties. Some automobile manufacturers have already switched over to the new hfo class of refrigerant known as 1234yf. This article describes thermodynamic properties of the refrigerants the ideal refrigerant.
Detailed comparison is made on first generation, second generation and third generation refrigerants, including the option of using hcs and co 2. Types of refrigerants and their environmental impact. R4a is capable to be at temperatures of 28c at room temperatures of 38c, its performance being very similar to that of an r12. Toxicity classification of refrigerants is assigned to classes a or b. Chlorofluorocarbons cfcs, hydrochlorofluorocarbons hcfcs and hydrofluorocarbons hfcs are synthetic substances used as refrigerants. Shortcuts to remember designation and their chemical formula for organic refrigerants, refrigerants are r11, r12, r22, r1, r114, r4. Properties of azeotropic refrigerants are entirely different from those of their components and may be conveniently treated as a single chemical compound. R12 overview r12 is r4as older predecessor, and it was used in most automotive air conditioning systems, as well as in household refrigerators. Of the refrigerants listed in the last two groups, only. Because of the similarities between r22, r11, and r12, only r12 is discussed. A number of materials have physical and thermodynamic properties suitable for their use as refrigerants.
By the end of the 1980s the first nonchlorinated refrigerant, r4a, was on the market. Refrigerant distribution national refrigerants, inc. However, hfcs still dominate the market outright and natural refrigerants, despite their superior properties, still. Particularly, for flooded type evaporator or condenser, the refrigerant amount required is high and their cost needs to be factored in while making the initial investments. Here are some of the desirable properties of refrigerant explained in detail. Properties of refrigerants n low boiling point and high latent heat of vaporization n dense vapor n low toxicity n non flammable n low miscibility with oil n low cost. Many different refrigerants have been used in the past and are in use today with good ability to transfer heat from one place to another. Ozone depletion potential odp and global warming potential gwp. It is odorless, nontoxic, nonflammable, nonexplosive and noncorrosive. In the last two centuries, human ingenuity made it. Ashrae position document on refrigerants and their. Even though their high rate of flammability prevents them from being used commonly, the propanebutane and propaneisobutene mixtures are good alternatives to r12 in house type coolers. Without being pressureregulated, primary refrigerants absorb all available heat.
Synthetic and organic refrigerants are classified under two main categories, primary and secondary. One way of reducing the amount of these refrigerants and the risk of leakage is to chill a secondary refrigerant, such as glycol or brine, in a centralized plant room and circulate this rather than the primary refrigerant. Product information sorted by product type and name type product r number odp1 gwp2 cfc 12 1 high 10900 high 502 0,33 high 4657 high hcfc 22 0,055 medium 1810 medium 123 0,060 medium 77 low 401a 0,033 medium 1182 medium. Class a signifies refrigerants for which toxicity has not been identified. R410a is primarily used for home and commercial units made on or after 2010. Low boiling temperature at atmospheric of the refrigerant is desirable. The oil and refrigerant should be miscible to assure that the oil is transported out of the refrigeration circuit and not accumulated in the system.
It has long been used in a variety of airconditioning and refrigeration applications in a variety of markets. Pdf refrigerant types, issues, trends and future options. The conversion of equipment and systems using cfcs has not yet been completed. Refrigerants are divided into groups according to their chemical composition. Many of the early refrigerants such as sulfur dioxide, methyl chloride and ammonia met that objective but posed safety hazards due to their. A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle. A comparison between refrigerants used in air conditioning. The replacement of cfc refrigerants to those more environmentally friendly was not easily achieved.
Refrigerant r12 is utilized as a part of household fridges and coolers, fluid chillers, dehumidifiers, ice producers, water coolers, drinking fountains and transport refrigeration. The refrigerants are expensive and have negative environmental impacts when released to the atmosphere. This cycle is repeated over and over with the same fluid. Those that are insoluble in oil in the operating temperature range. Refrigerants are substances, often in liquid form that are used in a refrigeration cycle to cool a certain space.
Not all refrigerants of this type are labelled as freon since freon is a brand name for the refrigerants r12, rb1, r22, r410a, r502, and r503 manufactured by the chemours company. Ashrae position document on refrigerants and their responsible use 2 executive summary refrigerants are the working fluids in refrigeration, airconditioning, and heatpumping systems. Many working fluids have been used for such purposes. In fact, from the thermodynamic or heatcarrying standpoint, differences among refrigerants with similar. A balanced approach refrigerant history in the early years, the primary focus of the hvac industry was simply on finding a refrigerant that would provide effective cooling. They absorb heat from one area, such as an airconditioned space, and reject it into another, such as outdoors, usually through evaporation and condensation.
The main types of air conditioners and refrigerators are a vapor. Detailed comparison is made on first generation, second generation and third generation refrigerants, including the option of. Refrigerants are widely used in refrigeration cycle where cooling effect below the atmospheric temperatures are needed. Refrigerants thermodynamic, physical, chemical, safety related and environmental properties have been presented and discussed in the first part of the paper. Refrigerant storage examples not part of standard sample sensor locations 4455 no open flames that use combustion air from the machinery room boilers can be located within the mechanical as long as the combustion air is ducted from the outside to the boiler or shut down sensors are installed 8. Although properties of nearazeotropic refrigerants are nearer to azeotropic than to non. Thermodynamic properties of refrigerant r22 properties of r22 vapor volume, enthalpy and entropy at pressures from 30 to 260 psia tag search en.
Chemical refrigerants are assigned an r number which is determined systematically according. A refrigerant with a ozonedepletion potential odp damages the ozone layer, which is an entirely separate issue from climate change. Nearazeotropic refrigerants are blends whose characteristics are near to azeotropic. Whenever we choose them for particular use properties of refrigerants also plays a vital role in economic and environmental friendly application. Then the refrigerant changes back into liquid form, and travels back into the evaporator. Refrigerant recovery unit 17 test flashcards quizlet. There are some refrigerants which are highly inflammable and so their. On the contrary, the illegal market for this type of refrigerants flourishes worldwide, and it is estimated that no more than 50% of cfc systems worldwide have been upgraded. Comparison of environmental impacts and physical properties of refrigerants ko matsunaga executive summary even before the invention of refrigeration, people wanted to improve their life by using ice to provide cold drinks and preserve food.
As such, there is no refrigerant that can be advantageously used under all operating conditions and in all types of refrigeration systems. However, the compressor must use a synthetic polyester lubricating oil. The heat is released in the condenser component of the system. Refrigerants thermodynamic, physical, chemical, safe ty related and environmental properties have. The refrigerant in any refrigerator or air conditioner flows continuously through the vapor compression cycle, absorbing the heat in the evaporator and releasing it in the condenser. Most of the refrigerants that are to be compared against one another in a simple coolant cycle are chosen from hydrocarbons in this study too. Primary refrigerants change states to absorb heat from surrounding areas or substances. Demonstrate knowledge of the physical properties of commonly used refrigerants. For example, the classification of halogen refrigerants derived from saturated hydrocarbons and consisting of only one substance is illustrated in fig. Refrigerants physical properties engineering toolbox. In general, all refrigerants are characterised by two numbers. Range critical point, toxicity, lower explosive limit, azeotrope, zeotrope, odp, gwp. Safety properties of refrigerants considering flammability and toxicity are defined by ashrae standard 34 1.
As for example, we cannot allow a toxic refrigerant to be used for air conditioning in residential buildings. Nextgeneration low global warming potential refrigerants. They are grouped into class a or b, depending on their. There is no ideal refrigerant on the market that has the desired thermodynamic properties, is easy to make and doesnt pose any human or environmental hazards. The following is a list of refrigerants with their type prefix, ashrae designated numbers, iupac chemical name, molecular formula, cas registry number blend name, atmospheric lifetime in years, semiempirical ozone depletion potential, net global warming potential over a 100year time horizon, occupational exposure limitpermissible exposure. Refrigerants and their environmental impact substitution of hydro chlorofluorocarbon hcfc and hfc hydro fluorocarbon. Tricks to remember designation and their chemical formula. An introduction to a2l refrigerants and their use in. The paper on refrigerants has been divided in two parts. Refrigerants are substances that can be used in the refrigeration cycle of air conditioning and refrigeration equipment because of their thermodynamic properties.
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