Learn vocabulary, terms, and more with flashcards, games, and other study tools. 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. It has the highest refrigeration effect per kilogram of all refrigerants and comes at a low cost. R32 has a gwp about one third that of r410a, and it has excellent properties. New, natural and alternative refrigerants by dr s f pearson of star refrigeration limited introduction it is an honour to be invited to present this paper despite the rather daunting title. Because of the similarities between r22, r11, and r12, only r12 is discussed. What is a refrigerant and desired properties of a refrigerant free download as pdf file. Any substance which has appropriate thermal properties can be used as a refrigerant, but in practice the choice is limited by many factors such as toxicity, flammability, chemical stability, and the behaviors of the refrigerant with lubricating oil, water and construction materials. Pdf refrigerant types, issues, trends and future options.
Naturally, refrigerants with as a low a value of tewi are preferable from global warming point of view. High latent heat of refrigerant at evaporator temperature is desirable. The refrigerants have a thermodynamic property charge. Pdf influence of refrigerant r4ar1234yf properties. These refrigerants will evaporate at cold temperatures and so the heat absorbed is in the form of latent energy. The weight of the refrigerant required to be circulated in the system per unit of refrigerating effect will be low if the latent heat of refrigerant is high. High conductivity of refrigerant in both states are desirable.
The refrigerants should be chemically stable as long as they are inside the refrigeration system. Ecofriendly refrigerants h c f c r 2 2, r 1 2 4 h f c r 1 3 4 a, r 1 5 2 a n a t u r a l r e f r i g e r a n t n h 3, h c s c f c a l t e r n a t i v e s. R32 and r125 are seldom used as single refrigerants, but only in mixtures with particularly favorable thermodynamic properties. Table of contents 2018 ashrae handbookrefrigeration. Class a signifies refrigerants for which toxicity has not been identified. Refrigerants properties pdf product data summary and thermodynamic tables. Dec 12, 2005 this article has been excerpted from a comprehensive white paper, refrigerants for commercial refrigeration applications, issued by copeland corp. 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. With the discovery of the damaging effect of cfcs and hcfcs refrigerants to the ozone layer, the hfc family of refrigerant has been widely used as their replacement. Halocarbon refrigerants halocarbon refrigerant are all. The text, which contains worked examples, is intended for use as an elective undergraduate paper for 3rd or 4th year engineering students. Ozone depletion potential odp of a chemical compound is the relative amount of degradation it can cause to the ozone layerglobal warming potential gwp is a measure of how much a given mass of a gas contributes to global warming.
Thermophysical properties of refrigerants t his chapter presents data for thermodynamic and transport properties of refrigerants, arra nged for the occasional user. Usually, a fluid, used in a heat pump and refrigeration cycle that can extract heat from another body or substance. System should possess some desirable properties like the refrigerant should be more volatile than the absorbent in other words the boiling point of refrigerant should be much lower than the absorbent. R22 chc1f425 and r11 cc1435f are colorless, nonexplosive, nonpoisonous refrigerants with many properties similar to those of r12. 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. Risk assessment of refrigeration systems using a2l.
Properties of a good refrigerants mechanical engineering. There must be large difference in the boiling points of refrigerant and absorbent greater than 2000 0c, so. Polyalkylene glycol pag soluble or partially soluble with hc refrigerants depending upon the conditions. Refrigerant is the life blood of the vapor compression cycle. New refrigerants to replace cfcs comprise an active area of development. Refrigerants are substances that can be used in the refrigeration cycle of air conditioning and refrigeration equipment because of their thermodynamic properties. The free water apart from the dissolved water in refrigerant freezes below 0 deg c. Positively innovative refrigerants r32 daikin chemical europe. It is the fluid that flows continuously through the refrigeration cycle or vapor compression cycle absorbing heat from the low temperature reservoir and throwing it to the atmosphere or any other high temperature reservoir.
This paper presents the investigation results of hfc refrigerants r125, r143a, r152a and r32 which prevent the ozone layer. Here are some of the desirable properties of refrigerant explained in detail. R4a is capable to be at temperatures of 28c at room temperatures of 38c, its performance being very similar to that of an r12. Refrigerants color codes refrigerants and their color codes. A refrigerant with a lower boiling point tends to have a better ability to cool. Key properties of the main refrigerants are given in together with their typical application ranges. Ashrae position document on refrigerants and their. Secondary refrigerants allow the amounts of environmentally harmful primary refrigerants to be minimized and contained in a restricted area.
The institute of refrigeration refrigerants americas. Chlorofluorocarbons cfcs, hydrochlorofluorocarbons hcfcs and hydrofluorocarbons hfcs are synthetic substances used as refrigerants. The following is a list of refrigerants with their typeprefix, 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. A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration. Polyol ester poe generally exhibit excessive solubility with hc refrigerants. In refrigeration and air conditioning applications there are wide range of conditions in which the refrigerants. Refrigerants are widely used in refrigeration cycle where cooling effect below the atmospheric temperatures are needed. Some important physicalchemical properties of refrigerants. Some comments on the refrigerants presented in the table are given below. Classification can be divided into class 1, class 2, class 3.
The september 2017 addendum 1 has been incorporated into the already published 2017 version of. The article focuses on the criteria for refrigerant selection, including discussion of the transitional refrigerants hcfcs, chlorine free refrigerants hfcs, and halogen free refrigerants. With regard to environmental impacts, the preferable refrigerant is butane. Mle is a method for estimating parameters of a statistical model. The thermodynamic efficiency of a refrigeration system depends mainly on its operating temperatures. This article presents a comparison of the properties and performance of hydrocarbons as refrigerants in smallsize heat pump and refrigeration systems of several. 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. This data is necessary for designing the pumping units of the system. The method used to solve for new refrigerants was achieved using an iterative method based on group contribution theory. Desirable properties of refrigerants chemical engineering site. Thermodynamic properties of duponttm freonr 22 refrigerant author. 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. Fellow ashrae mcquay international staunton, virginia usa 1 what is a refrigerant.
Following are the desirable properties of a primary refrigerant. Low viscosity of the refrigerant in both states are desirable. The flood of the airconditioner, that is, the refrigerants, their properties, merits and demerits are summarized to map the various types and their classifications. Whenever we choose them for particular use properties of refrigerants also plays a vital role in economic and environmental friendly application. Safety properties of refrigerants considering flammability and toxicity are defined by. It has long been used in a variety of airconditioning and refrigeration applications in a variety of.
Possible replacements for these refrigerants in commercial applications include ashrae class 2l refrigerants, which have lower global warming potentials but are mildly flammable. Desirable properties of refrigerants used in refrigeration. Incorporating product design into the development of new. The refrigerant is the fluid that is used in the vapor compression refrigeration system for carrying the heat from the substance or the fluid to be cooled and throws it to the atmosphere. Detailed comparison is made on first generation, second generation and third generation refrigerants, including the option of using hcs and co 2. These two refrigerant thermodynamic properties are similar to each other, making it a desirable choice for future automotive refrigerants. May 01, 2014 following are the desirable properties of a primary refrigerant. In addition, a chapter is devoted to the issue of refrigerant selection, and a further chapter focuses on refrigerating devices that do not operate the vapour compression cycle. In todays world, other properties of the refrigerant are more important. The purpose of this standard is to establish purity specifications, to verify composition, and to specify the associated methods of testing for acceptability of the refrigerants listed in section 2. Working fluids in refrigeration cycles undergoes phase transition in cycles mostly before going to subject topic first of all we divide all refrigerants in following categories.
The refrigerants should preferably be nonflammable and nonexplosive. A blank numerically shows the thermodynamic properties of a refrigerant under saturated conditions. Refrigerants are divided into groups according to their chemical composition. Which of the following is not a desirable property for new refrigerants. Originally the title given was new and alternative refrigerants but i was also asked to. Duponttm refrigerants, technical information keywords. Refrigerant containment, recovery, recycling, and reclamation. This article has been excerpted from a comprehensive white paper, refrigerants for commercial refrigeration applications, issued by copeland corp. Lets look at the properties of these and other refrigerants. In addition, if the volume of charge is large, there should be no danger to health and property in case of its escape. They finally chose dichlorodifluoromethane freon as having the most desirable characteristics, thus introducing the first chlorofluorocarbons. The primary refrigerants used in commercial reachin and walkin coolers are r404a and r4a, greenhouse gases with global warming potentials gwps in excess of 1,400. 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. Refrigerants should have low freezing point than the normal operating conditions.
The liquid has to vapourise at the evaporator coil to cause cooling. Learn the types of refrigerants bright hub engineering. Examples of secondary refrigerants include water, air, hydrocarbons, ammonia and carbon dioxide, which are more environmentally benign than traditional refrigerants such as hcfcs. The usage of oil free compressors solves many of the problems that lubricants consisting of a mixture of oil and refrigerant cause. In fact, from the thermodynamic or heatcarrying standpoint, differences among refrigerants with similar boiling points are small. Synthetic and organic refrigerants are classified under two main categories, primary and secondary. Toxic pressures to the previous refrigerant with zero odp from dupont halogen free refrigerants 09. The properties examined in this study were toxicity, flammability, explosion potential, global warming potential, ozone depletion potential and efficiency. This section presents data for the thermodynamic and transport properties of refrigerants, arranged for the occasional users. Ammonia is highly toxic but it has excellent thermal properties and low volumetric displacement. Refrigerants are classified according to their way of absorption or extraction of heat from substances stored in the refrigerator. Refrigerants and their application presented by thomas e. R4a is also known as tetrafluoroethane cf3ch2f from the family of hfc refrigerant.
Compressor has to be operated at high vacuum if the boiling point of the refrigerant is high at atmospheric pressure. In fact, from the thermodynamic or heatcarrying standpoint, differences among refrigerants with similar. Refrigerants such as air, water and carbon dioxide are used but most refrigerants are those designed for vapour compression cycles. However, important practical issues such as the system design, size, initial and operating costs, safety, reliability, and serviceability etc.
Without being pressureregulated, primary refrigerants absorb all available heat from perishable goods until theyre frozen solid. Jul 17, 2017 a refrigerant with a lower boiling point tends to have a better ability to cool. Pdf refrigeration and airconditioning play a vital role in domestic and industrial. Nist standard reference database 23, refprop thermo dynamic properties of refrigerants and refrigerant mixtures, version 3. Physical properties of refrigerants low freezing point. For flammable refrigerants special precautions should be taken to avoid accidents. Mixtures of r12 vapor and air, in all proportions, will not irritate your eyes, nose, throat, or lungs. Toxicity classification of refrigerants is assigned to classes a or b. A blend of ab and m oils achieving desirable properties for use with hc refrigerants. This liquid, sweet, colorless refrigerant has a nonirritating odor, is nonflammable and nontoxic. The thermodynamic properties of refrigerants columbushoa.
R32 is a chlorinefree, ozonesafe fluorocarbon whose boiling point is 52c. Primary refrigerants change states to absorb heat from surrounding areas or substances. This property of refrigerant in both states carries importance for calculating heat transfer coefficients in evaporators and condensers. However, hcfc refrigerants r123 and r22 do not completely prevent the ozone layer depletion. 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.
This article describes thermodynamic properties of the refrigerants the ideal refrigerant. Common refrigerants and their ozone depletion potential odp and global warming potential gwp are indicated below. This article is the brief overview of what are refrigerants and the history of refrigerants. Refrigerants with higher boiling points tend to be more efficient and may work well in a smaller machine. 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. The process is not easy, and although there are alternatives to old refrigerants, the new ones are usually not. A number of materials have physical and thermodynamic properties suitable for their use as refrigerants. This also reduces the initial cost of the refrigerant used in the system. 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. If the oil has to be in the system it is of great importance that the lubrication issues are taken care of early. Jul 04, 2017 refrigerant nomenclature nomenclature of refrigerants refrigeration and air conditioning.
The production and use of cfcs is restricted by the montreal protocols. Apr 12, 2020 refrigerants are widely used in refrigeration cycle where cooling effect below the atmospheric temperatures are needed. Table a1 molar mass, gas constant, and criticalpoint properties table a2 idealgas specific heats of various common gases table a3 properties of common liquids, solids, and foods table a4 saturated watertemperature table table a5 saturated waterpressure table table a6 superheated water table a7 compressed liquid water table a8 saturated icewater vapor. What is a refrigerant and desired properties of a refrigerant scribd. Control of moisture and other contaminants in refrigerant systems 8. It is highly toxic but nonexplosive and nonflammable. 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. Following the discovery that some of these chemical compounds may be harmful to the environment, they are being replaced with more environmentally friendly alternatives see figure 5. Equipment and system dehydrating, charging, and testing 9. Desirable properties of refrigerants desirable refrigerants are those which possess chemical, physical, and thermodynamic properties that permit their efficient application and service, in practical designs of refrigerating equipment. The desired thermodynamic properties are a boiling point somewhat below the target temperature, a high heat of vaporization. These physical properties of refrigerants help us select the proper refrigerant for the application as per our requirement. Since different fluids have the desired traits in different degree, choice is a matter of. In some applications it may be necessary to consider other properties of the refrigerant, such as its interaction with the process fluid in the event of a pinhole leak.
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