In the last two centuries, human ingenuity made it possible to control fully. Cfc 12 and hcfc 22 have an aggregated average above 51%. By considering only the most fundamental thermodynamic criteria it is possible to establish a link between bulk properties and molecular structure. They have also been in use in refrigeration plants in the past, and are still used in some industrial plants. All refrigerants are dangerous if misused or applied incorrectly. In addition, if the volume of charge is large, there should be no danger to health and property in case of its escape. Pdf american council for an energyefficient economy aceee. Effects of refrigerant properties on refrigerant performance citeseerx. Polyalkylene glycol pag soluble or partially soluble with hc refrigerants depending upon the conditions.
Hence, the study for the performance characteristics for refrigerants has become necessary in order to evaluate an ecofriendly refrigerant which is bound to protect the environment from dreadful substances. A comparison between refrigerants used in air conditioning. Another disadvantage is that it requires a very high. An important property of a secondary refrigerant is its freezing point. Key properties of the main refrigerants are given in together with their typical application ranges. A number of materials have physical and thermodynamic properties suitable for their use as refrigerants.
What is a refrigerant and desired properties of a refrigerant free download as pdf file. Hydrocarbons natural refrigerants for lowering gwp danfoss. Classification, properties, selection and charging of it. The suitability of a refrigerant for a certain application is determined by its physical, thermodynamic, chemical properties and by various practical factors. It would not cause ozone depletion or climate change. Desirable refrigerants are those which possess chemical, physical, and thermodynamic properties that permit their efficient application and service, in practical designs of refrigerating equipment. Refrigerants are widely used in refrigeration cycle where cooling effect below the atmospheric temperatures are needed. Out of the above four, freon is the most commonly used refrigerant on board as it has almost all the desirable properties of refrigerants as mentioned above.
The cfcs r12, r11, r114 and r502 together with hcfc r22 became the definitive refrigerants. Thermodynamic properties of duponttm freonr 22 refrigerant author. Low boiling point otherwise operation at high vacua becomes a necessity low condensing pressure to avoid. Oct, 2015 a lubricant is a substance introduced to reduce friction between surfaces in mutual contact, which reduces the heat generated.
The ideal working fluid or often called refrigerant would have favorable thermodynamic properties, be noncorrosive to mechanical components, and be safe, including freedom from toxicity and flammability. Safety hydrocarbons are highly flammable and must be handled with care. The liquid has to vapourise at the evaporator coil to cause cooling. To enable the use of smaller compressors and other equipment the refrigerant should have smaller vapor. Thermodynamic properties of duponttm freonr 22 refrigerant. They may be listed as a the high specific heat of vaporization. Jul 17, 2017 a refrigerant with a lower boiling point tends to have a better ability to cool. Hfc refrigerants are not miscible with the mineral oils used in cfc refrigeration systems. 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. Desirable properties of refrigerants chemical engineering site. R4a is capable to be at temperatures of 28c at room temperatures of 38c, its performance being very similar to that of an r12. While having less impact on the environment, flammable. High critical temperature to have large isothermal energy transfer. Refrigerants color codes refrigerants and their color codes.
Solstice yf was originally developed as a low global warming potential replacement for r4a in the automobile air. Refrigerants properties pdf product data summary and thermodynamic tables. Physical properties of refrigerants refrigerant mol. Learn the types of refrigerants bright hub engineering. Compressor has to be operated at high vacuum if the boiling point of the refrigerant is high at atmospheric pressure. In particular, physical properties of refrigerants are useful for determining the applicability of a refrigerant under design operating conditions. 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. Safety properties of refrigerants considering flammability and toxicity are defined by ashrae standard 34 1. But developing the perfect fluid with all of the desired properties of an ideal. What are the desirable properties of refrigerants primary. The refrigerants have a thermodynamic property charge. Safety properties of refrigerants considering flammability and toxicity are defined by. The design of the refrigeration equipment depends strongly on the properties of the selected refrigerant.
May 01, 2014 following are the desirable properties of a primary refrigerant. Properties of common hc refrigerants ashrae handbook fundamentals 20. The working fluid desirable properties are related to thermodynamic and physical properties which lead to efficient cooling or heating factor and effective design of equipment, such as high evaporation heat, high volumetric refrigeration capacity, low temperature at. Solstice yf was originally developed as a low global warming potential replacement for r4a in the automobile airconditioning application. The refrigerants have a thermodynamic property chart on pressureenthalpy coordinates with an abbreviated set of tabular data for saturated liquid and vapor on the faci ng page. In fact, from the thermodynamic or heatcarrying standpoint, differences among refrigerants with similar. The search for alternative refrigerants a molecular approach. Toxicity classification of refrigerants is assigned to classes a or b.
While having less impact on the environment, flammable refrigerants are significantly more easily. The vast number of refrigerants available in the market today allows us to choose a refrigerant depending upon the operating conditions of the refrigeration. These are highly inflammable refrigerants and this group is defined by a lower flammability limit of less than or equal to 0. The working fluid desirable properties are related to thermodynamic and physical properties which lead to efficient cooling or heating factor and effective design of equipment, such as high evaporation heat, high volumetric refrigeration capacity, low temperature at the end of the compression. Jul 04, 2017 refrigerant nomenclature nomenclature of refrigerants refrigeration and air conditioning. Guidelines for the use of hydrocarbon refrigerants in. The simulator used an equation of state to predict the thermodynamic properties of the refrigerant mixtures. What is a refrigerant and desired properties of a refrigerant scribd. Properties of refrigerants n low boiling point and high latent heat of vaporization n dense vapor n low toxicity n. Natural and synthetic refrigerants, global warming.
This brochure provides selected properties information for solstice yf including thermodynamic data, transport prop erties, and flammability characteristics. 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. It has a disadvantage of low critical temperature thus have difficulty in liquefying. A comparison between refrigerants used in air conditioning derya ozkan, ozden agra and ozlem cetin university of yildiz technical university, turkey corresponding email. Low boiling point otherwise operation at high vacua becomes a necessity low condensing pressure to avoid heavy machine plant scantling and reduce the leakage risk. Class a signifies refrigerants for which toxicity has not been identified.
Ashrae position document on refrigerants and their responsible use 5 a broad range of fluids has been used as refrigerant over the past century, and the current usage is dominated by a range of fluorinated chemicals, such as hfcs, in addition to hydro. Chemical properties, desirable properties of refrigerants. Refrigerants with higher boiling points tend to be more efficient and may work well in a smaller machine. However, the compressor must use a synthetic polyester lubricating oil. Hydrocarbons have excellent thermodynamic properties, and in this respect they are as good as or better than hcf or hcfc refrigerants in most applications. R22 chc1f425 and r11 cc1435f are colorless, nonexplosive, nonpoisonous refrigerants with many properties similar to those of r12. A refrigerant must satisfy many requirements, some of which do not directly relate to its ability. Refrigerant selection involves compromises between conflicting desirable thermophysical properties. Because of the similarities between r22, r11, and r12, only r12 is discussed. Apr 12, 2020 refrigerants are widely used in refrigeration cycle where cooling effect below the atmospheric temperatures are needed. These physical properties of refrigerants help us select the proper refrigerant for the application as per our requirement. Needless to say, none of the liquid has all these properties.
Desirable properties and commonly used refrigerants. This section presents data for the thermodynamic and transport properties of refrigerants, arranged for the occasional users. Hence, new synthetic ester lubricants were developed for this application. Usually, a fluid, used in a heat pump and refrigeration cycle that can extract heat from another body or substance. Duponttm refrigerants, technical information keywords. Thermophysical properties of refrigerants t his chapter presents data for thermodynamic and transport properties of refrigerants, arra nged for the occasional user. The good properties of a refrigerant are as follows. The general conclusion of the thesis is that the refrigerant affects all of the measured properties negatively on the subject of lubrication and life of the rolling element bearing. Mixtures of r12 vapor and air, in all proportions, will not.
Refrigeration equipment an overview sciencedirect topics. Guidelines for the use of hydrocarbon refrigerants in static. Considerations for next generation hvac refrigerants. Which of the following is not a desirable property for new refrigerants high boiling point which of the following refrigerants has a low gwp and can be used as a replacement for r4a in automotive air conditioning. Choosing a refrigerant is a balancing act that seeks to maximize a number of. Which of the following is not a desirable property for new refrigerants high boiling point which of the following refrigerants has a low gwp and can be used as a. Chemical properties assignment help, chemical properties homework help, desirable properties of refrigerants tutors. Polyol ester poe generally exhibit excessive solubility with hc refrigerants. In fact, from the thermodynamic or heatcarrying standpoint, differences among refrigerants with similar boiling points are small. In todays world, other properties of the refrigerant are more important. For more comprehensive data the refrigerant supplier or reference texts should be consulted. 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. Refrigerants are widely used in refrigeration cycle where cooling effect below the.
In particular they were nontoxic, nonflammable and with good thermodynamic prop erties and oil miscibility characteristics. In the last two centuries, human ingenuity made it. Jun 02, 2019 a refrigerant is a substance or mixture. While nonfluoronated refrigerants sometimes called natural refrigerants have some desirable characteristics in vapor compression coolin g, the majority of the hvac industry is arguably best served by using fluorocarbon refrigerants because. Ashrae position document on refrigerants and their. Low boiling temperature at atmospheric of the refrigerant is desirable. Whenever we choose them for particular use properties of refrigerants also plays a vital role in economic and environmental friendly application. Following are the desirable properties of a primary refrigerant. A blend of ab and m oils achieving desirable properties for use with hc refrigerants. The liquid at the evaporator coil should therefore vapourise easily, otherwise the compressor will have to create too much of vacuum to cause the liquid to vapourise. They finally chose dichlorodifluoromethane freon as having the most desirable characteristics, thus introducing the first chlorofluorocarbons. This article describes thermodynamic properties of the refrigerants the ideal refrigerant. Here are some of the desirable properties of refrigerant explained in detail.
1146 468 1481 436 1146 796 634 1205 1 1315 1108 1009 314 177 204 836 1080 1279 1561 404 924 255 627 595 886 1434 591 814 1161 318 942 1584 809 595 1097 388 1147 456 759 1118 662 922 128