It was soon evident, though, that the lack of chlorine and that the new ester oils did not have the same good lubrication properties as mineral oil and cfc refrigerants. Detailed comparison is made on first generation, second generation and third generation refrigerants, including the option of using hcs and co 2. For example, the classification of halogen refrigerants derived from saturated hydrocarbons and consisting of only one substance is illustrated in fig. Compressor has to be operated at high vacuum if the boiling point of the refrigerant is high at atmospheric pressure. As for example, we cannot allow a toxic refrigerant to be used for air conditioning in residential buildings.
Desirable properties and commonly used refrigerants. New refrigerant development 10 develop techniques for detecting and dramatically reducing refrigerant leakage in currently installed. 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. A number of materials have physical and thermodynamic properties suitable for their use as refrigerants. A refrigerant with a ozonedepletion potential odp damages the ozone layer, which is an entirely separate issue from climate change. R22 light green r4a light sky blue r404a orange the name label of the gases are given on the cylinder. Refrigerants release heatby condensing from a vapor to a liquid 5. After studying this unit, you should be able to learn the different classifications of refrigerants, naming convention for refrigerants, properties of individual refrigerants, and.
The specific heat of liquid should be as small as possible and of vapour should be as high as possible to give less superheating of vapour. Jun 02, 2019 a refrigerant is a substance or mixture. Cfc 12 and hcfc 22 have an aggregated average above 51%. Refrigerant is the fluid used for heat transfer in a refrigerating system that absorbs heat. 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.
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. These refrigerants are primarily used for air conditioning and heat pumps and have replaced r22 in many applications. The hydrofluorocarbons are refrigerants that contain no chlorine and are not harmful to the ozone layer odp 0, see section 5. Ashrae position document on refrigerants and their responsible use 2 executive summary refrigerants are the working fluids in refrigeration, airconditioning, and heatpumping systems. Hence, new synthetic ester lubricants were developed for this application. A comparison between refrigerants used in air conditioning. The paper on refrigerants has been divided in two parts. Thermodynamic properties of duponttm freonr 22 refrigerant author. While having less impact on the environment, flammable refrigerants are significantly more easily. Here are some of the desirable properties of refrigerant explained in detail.
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. Sep 17, 2014 color codes of refrigerants easy recognize gas cylinder different refrigerant has different color coding few examples are given below. Fellow ashrae mcquay international staunton, virginia usa 1 what is a refrigerant. Due to the chlorine molecules ability to destroy the earth ozone layer by converting it to oxygen the international communities have agreed through a number of conventions to bring about its phaseout of such refrigerants. The flood of the airconditioner, that is, the refrigerants, their properties, merits and demerits are summarized to map the various types and their classifications. This article describes thermodynamic properties of the refrigerants the ideal refrigerant. It has long been used in a variety of airconditioning and refrigeration applications in a variety of markets. Examples of secondary refrigerants include water, air, hydrocarbons, ammonia and carbon dioxide, which are more environmentally benign than traditional refrigerants such as hcfcs. Refrigerants that commonly used mineral oils were your cfc and hcfc refrigerants such as r12, r22, and r502.
A general definition of refrigerant isfluid used in refrigeration system for transferring heat 3. Hfc refrigerants are not miscible with the mineral oils used in cfc refrigeration systems. Refrigerants are substances, often in liquid form that are used in a refrigeration cycle to cool a certain space. 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. Refrigerant is the life blood of the vapor compression cycle. Greenhouse effect global warming clean air act caa alternative refrigerants. Request pdf properties of refrigerant, oil and their mixture in most vapourcompression refrigeration systems, a certain amount of lubricant oil is used to lubricate moving parts. For decades, freon refrigerants have been chosen for their performance and safety for all residential and commercial ac, heat pumps, and refrigeration. The journey toward compliance has caused the hvac equipment and appliance industries to revisit the potential use of substances that have good environmental and thermodynamic properties as refrigerants, but which are also, unfortunately, flammable. Characteristics solstice 452a r452a is a nonozonedepleting, non. Section 2 discusses the environmental impacts of refrigerants through their life.
Natural and synthetic refrigerants, global warming. The standard industry number designation for each refrigerant is the signed by. The following is a list of refrigerants with their type prefix, ashrae designated numbers, iupac chemical name, molecular. Refrigerants refrigeration systems and applications. Refrigerants and vars refrigerants and their properties the working agent in a refrigerating system that absorbs carries or releases heat from the place to be cooled or refrigerated can be termed as a refrigerant. Sustainability safeguards longterm investments and ensures compliance with corporate social responsibility csr. Genetron properties suite provides results in tabulated form exportable to excel and in diagrams you are used to pressureenthalpy, temperatureentropy. However, their impact on global warming is very large compared with traditional refrigerants. Chlorofluorocarbons cfcs, hydrochlorofluorocarbons hcfcs and hydrofluorocarbons hfcs are synthetic substances used as refrigerants. Mineral oils can also be used with other refrigerants such as ammonia or some hydrocarbons as well. All refrigerants are dangerous if misused or applied incorrectly.
Duponttm refrigerants, technical information keywords. Secondary refrigerants allow the amounts of environmentally harmful primary refrigerants to be minimized and contained in a restricted area. Influence of those properties, which is of the utmost significance on the vapor compression process effi. High latent heat of vaporization to get more refrigeration effect. Refrigerants with suitable properties are chosen for selective cooling and heating applications.
The process is not easy, and although there are alternatives to old refrigerants, the new ones are usually not flawless. Possible replacements for these refrigerants in commercial applications include ashrae class 2l refrigerants, which have lower global warming potentials but are mildly flammable. Thermodynamic properties of duponttm freonr 22 refrigerant. Usually, a fluid, used in a heat pump and refrigeration cycle that can extract heat from another body or substance. The refrigerant in a mechanical compression system absorbs andchange state 2. 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. An understanding of the pressuretemperature relationship of refrigerants as theypass through the refrigeration compression cycle also will help you as you study this chapter on refrigerant tables.
The infoimation developed in this study on the environmental impacts and the properties of various refrigerants can be used by designers in seeking to provide better and environmentally friendlier refrigeration and air conditioning systems. Pdf refrigerant types, issues, trends and future options. Types of refrigerants and their environmental impact. The choice of the refrigerant is not only the technical problem, it is subject to lot of interests, public and in dustrial groups advocate their positions and neutral po. Refrigerant development and legal situation stratospheric ozone depletion as well as atmospheric greenhouse effect due to refrigerant emissions have led to drastic changes in. It is responsible for capturing heat and then releasing it to another space by using the thermodynamic phenomena of phase changes wherein fluid changes into gas. Their report showed that chlorine was a key factor in the destruction of the ozone layer in the upper atmosphere. In fact, from the thermodynamic or heatcarrying standpoint, differences among refrigerants with similar. The good properties of a refrigerant are as follows. 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.
Refrigerants are widely used in refrigeration cycle where cooling effect below the atmospheric temperatures are needed. Without being pressureregulated, primary refrigerants absorb all available heat. Synthetic and organic refrigerants are classified under two main categories, primary and secondary. The most common hfc refrigerants available since the ban on hcfcs are presented in table 5. Further information can be found in the latest version of standard 34, available. 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 limit in parts per million volume per volume over a. High critical temperature to have large isothermal energy transfer. There are some refrigerants which are highly inflammable and so their direct use is forbidden for safety reasons. A summary of most common refrigerants and their oil compatibility is detailed below. R4a has relatively low pressure and therefore about 50% larger compressor displacement is required when compared to r22. Depending on temperature levels of the heat source and the heat sink, the application area of the working cycle can be refrigeration, air conditioning, or heatpumping. 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. Detailed comparison is made on first generation, second generation and third generation refrigerants, including the option of.
This unit is intended to serve as an introductory guide to the study of refrigerants. This heat transfer generally takes place through a phase change of the refrigerant. The r22 refrigerant which is used as an alternative to cfcincluded refrigerants, has got a low odp value and thus, its use is permitted until the year 2030. Risk assessment of refrigeration systems using a2l flammable. Desirable properties of refrigerants used in refrigeration applications like. There are some refrigerants which are highly inflammable and so their. Refrigerants are classified by ashrae, and their familiar r numbers are assigned according to certain rules. Modern hfc and hfo refrigerants tend to use polyolester poe oils, although some hfc blends specifically designed as dropin retrofit gases for cfcs and hcfcs may have some tolerance to mo and ab oils.
Ammonia and so2 can be detected by their characteristic smell. The globalwarming potential gwp of refrigerants now became a factor. Properties of oil and refrigerant mixtures lubrication of ball bearings in refrigeration compressors. Historically, oliver evans 1805 pioneered the idea of refrigeration by using ether. Effects of refrigerant properties on refrigerant performance citeseerx. In the last two centuries, human ingenuity made it possible to control fully. Whenever we choose them for particular use properties of refrigerants also plays a vital role in economic and environmental friendly application.
Purchasing freon refrigerants by the chemours company provides a reliable supply of highquality refrigerants to use in new equipment and retrofit opportunities, and to service. 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 limit in parts per million volume per volume over a timeweighted average twa concentration for a normal eighthour work day and a 40hour work. To enable the use of smaller compressors and other equipment the refrigerant should have smaller vapor density. This section presents data for the thermodynamic and transport properties of refrigerants, arranged for the occasional users. Desirable properties of refrigerants chemical engineering site. The choice of perfect refrigerant is made in view of its ideal thermodynamic properties, nondestructive nature, and security nonharmful and noncombustible. The tables contained on this page list approved refrigerant numbers from ansiashrae 342019, designation and safety classification of refrigerants, the latest edition of standard 34, which describes a shorthand way of naming refrigerants and assigns safety classifications based on toxicity and flammability data. In the 1990s, concerns grew that the refrigerants being phased in because of their favorable odp were contributing to global warming. Properties of commonly used refrigerants a refrigerant is a substance or mixture. For decades, freon refrigerants have been the trusted choice for their performance, reliability, and safety in air conditioning and refrigeration applications. 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. They absorb heat from one area, such as an airconditioned space, and reject it into another, such as outdoors, usually through evaporation and condensation.
Without being pressureregulated, primary refrigerants absorb all available heat from perishable goods until theyre frozen solid. Apr 12, 2020 refrigerants are widely used in refrigeration cycle where cooling effect below the atmospheric temperatures are needed. The refrigerants have a thermodynamic property charge. Due to their low odp, the phaseout dates for hcfcs were set out later from 2004 to 2030 2040 in developing countries. Refrigerants thermodynamic, physical, chemical, safety related and environmental properties have been presented and discussed in the first part of the paper. Refrigerant options now and in the future white paper. Freon refrigerant for more information on freon refrigerants, visit the information set forth herein is furnished free of charge and based on technical data that chemours believes to be reliable. Refrigeration as we know it has its origins in the. Ashrae position document on refrigerants and their. Refrigerants and their application presented by thomas e. Properties of refrigerants n low boiling point and high latent heat of vaporization n dense vapor n. R12 overview r12 is r4as older predecessor, and it was used in most automotive air conditioning systems, as well as in household refrigerators. This refrigerant was introduced commercially in the early 1960s for low temperature applications and is particularly suitable for hermetic compressors. Properties of refrigerant, oil and their mixture request pdf.
Low boiling temperature at atmospheric of the refrigerant is desirable. Chemical refrigerants are assigned an r number which is determined systematically according. This information is based on values calculated using the nist refprop database mclinden, m. Human society was using refrigeration technology, even before the invention of electricity in the 1880s. Refrigerant circulates within the refrigeration machine. May 28, 2018 cfc and hcfc refrigerants freon, arcton, etc. These physical properties of refrigerants help us select the proper refrigerant for the application as per our requirement. 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. Refrigerants are divided into groups according to their chemical composition.
It is intended for use by persons having technical skill, at their own risk. A familiarity with these diagrams will make this chapter easier. While having less impact on the environment, flammable refrigerants. Usually, a fluid, used in a heat pump and refrigeration cycle that can extract heat from another body or. However, hfcs still dominate the market outright and natural refrigerants, despite their superior properties, still.
Refrigerants are substances that can be used in the refrigeration cycle of air conditioning and refrigeration equipment because of their thermodynamic properties. Modeling and evaluation tools 2 characterize the heat transfer and thermodynamic properties and efficiency performance of new refrigerants and blends. Albeit numerous liquids can be utilized as a refrigerant, however in the twentieth century, cfcs turned into the most prevalent refrigerants. Primary refrigerants change states to absorb heat from surrounding areas or substances. In the hvac industry, refrigerants are used in various equipment such as air conditioners, refrigerators, freezers, etc.