**3. Refrigerants**

*Low-temperature Technologies*

GWP 150+

**Table 1.**

checked every 3 months.

*Source: Regulation (EU) N°. 517/2014 [5].*

*Equipment with dates for prohibiting the use of refrigerants.*

with the dates set out in **Table 1**.

The Article 4 of this Law establishes that stationary refrigeration equipment, air conditioners, and heat pumps must have an operator that checks for leakage points on the equipment according to the equivalent amount of CO2 in refrigerant charge where 5 or more equivalent tons of CO2 should be checked at least once a year. For equipment with an equivalent load above 50 tons of CO2, this check should be performed every 6 months. Systems with loads over 500 tons equivalent must be

**Equipment Prohibition** 

Household freezers and refrigerators with HFC refrigerant and greater than 150 GWP January 1, 2015 Cold rooms for commercial use HFC with GWP 2500+ January 1, 2020

Fixed refrigeration equipment with HFC refrigerant and with GWP greater than 2500 January 1, 2020

Mobile residential air conditioning equipment using HFC refrigerant with GWP 150+ January 1, 2020 Fixed residential air conditioners with load less than 3 kg and GWP 750+ January 1, 2025

Commercial central cooling system with a capacity of 40 kW or higher that works with

**date**

January 1, 2022

HFC with GWP 150+ January 1, 2022

Article 13 cites restrictions on the use of F-gas and imposes that from January 2020, the use of F-gas with GWP equal or greater than 2500 shall be prohibited in refrigeration systems with an equivalent load of 40 tons of CO2 or more. Nevertheless, if the fluid used in the system can be recovered, reprocessed, and

**Table 1** shows some air conditioning and refrigeration equipment with their

The questions of the regulation of refrigerants is the application of control mechanisms over the use and disposal of F-gas in each country in order to comply

For the purpose of facilitating the understanding about this chapter and the application in HVAC and refrigeration's systems, some definitions used by law and by some educational and research entities and institutions are presented below:

• **Global warming potential (GWP):** This is the direct mass comparison of CO2 that a fluid causes when released into nature over a 100-year period [5].

• **Tons of CO2 equivalent:** Quantity of mass with a global warming potential

• **Recovery or regeneration:** Process of gathering and direct F-gas storage equipment, i.e., the removal of a refrigerant from system to store it in an external tank [14]. In this process some contaminants found in the systems are removed, like oil, water, oleic acid, and hydrochloric acids. In this sequence, the refrigerant is distilled and then filtered, condensed, and analyzed, and if it complies with ARI 700 Standard (purity, humidity, acidity, non-condensable

gases, and maximum allowable residue levels), then it will be refilled.

• **Recycling:** Reuse of F-gas after a treatment process, that is, is the process involving the cleaning of refrigerant by an oil separator and a filter drier for

reused, it will have its utility extended until January 1, 2030.

multiplied by a global warming potential coefficient.

respective prohibition dates for their refrigerants.

**80**

Refrigerants can be defined as substances that serve as a means of transport and heat transfer, absorbing heat at low temperatures and rejecting it at higher temperatures [15]. From that definition, in principle, any substance that changes phase in the refrigeration or air conditioning cycle, from liquid to vapor during heat absorption and from vapor to liquid during heat rejection, may function as a refrigerant. Their commercial usefulness depends on the temperature ranges and pressure at which the system will operate and, more recently, the environmental impacts that eventually this refrigerant can cause when released into the environment.

Water and air can also be considered as fluid refrigerants, although they do not show phase change during the process as well as other synthetic fluids or not form aqueous solutions that are characterized by operating at temperatures below 273.16 K (0°C) without crystallizing.

Among the various properties that a refrigerant should include for use in air conditioning and refrigeration systems, the most important are [15]:

	- ix.Having adequate compatibility with the materials of the refrigeration system.
	- x.Be easy to detect.
	- xi.In case of leakage, it should not attack or spoil food, should not contribute to global warming, and should not attack the ozone layer.

xiii.Be commercially available at a reasonable cost.

The refrigerant groups available in the Brazilian market are divided into [15, 16]:

• **CFCs (chlorofluorocarbons):** They are refrigerant fluids whose molecule is formed by the element's chlorine, fluorine, and carbon, for example, the fluids R-11, R-12, R-113, R-114, R-115, and R-502, among others. The lifetime of CFCs in the atmosphere ranges from 60 to 540 years, causing high depletion of the ozone layer. Most CFCs have an ozone layer depletion potential (ODP) index ranging from 0.6 to 1.

CFCs were no longer manufactured by industrialized countries in January 1996 and, with some exceptions, by developing countries. These fluids feature high ODP and high GWP. According to the Montreal Protocol, in 1996 these gases were banned from developed countries, and in 2010 they should be banned from developing countries such as Brazil, but these gases are still found in old refrigeration and air conditioning systems. These fluids are used in automotive air conditioners, commercial refrigeration, and home refrigeration (refrigerators and freezers).

• **Hydrochlorofluorocarbons (HCFCs):** In these refrigerants some chlorine atoms are replaced by hydrogen, as an example of these fluids, have it R-22, R-123, R-401A, and R-4012A. These fluids are used in climate control systems, window air conditioners, split air conditioners, self-containers, cold rooms, etc.

These gases represent the second generation of fluorinated gases and were the main alternative to CFCs. They have lower ODP, but the GWP still between 1000 and 5000, so they are a little less harmful to the environment than their CFC predecessors, considering the ozone depletion. HCFCs are not fully halogenated like CFCs. The atmospheric lifetime of HCFCs ranges from 2 to 22 years, and therefore their ODP ranges from 0.02 to 0.1 [15, 17].

Currently, in Brazil, HCFC-22 or (R-22) has been the most commonly used refrigerant in air conditioning systems since the early 1990s. HCFCs have been used as transition fluids, and their restriction on use and manufacturing started in 2004. According to the Montreal Protocol, the elimination of HCFCs in developed countries is expected by 2030 and in Brazil by 2040. Nevertheless, some countries are already well advanced on their elimination. In the European Union the use of HCFCs was terminated in January 2010 and may still be used until January 2015 in some specific cases.

• **Hydrofluorocarbons (HFCs):** In these fluids all chlorine atoms are replaced by hydrogen, for example, R-134a, R-404A, R-407C, R-410A, etc. These fluids

**83**

*An Experimental Study of Synthetics and Natural Refrigerants Gases*

domestic refrigeration (refrigerators and freezers), etc.

(CO2), hydrocarbons, R718 (water), and R729 (air).

systems than HCFC and HFC fluids.

ensures a low risk of fire if a leak occurs.

to other types of fluids.

categories, which are:

are used in automotive air conditioning systems, commercial refrigeration and

As there are no chlorine atoms in HFCs refrigerants, they do not cause ozone layer depletion. HFCs are expected to become the most widely used in air conditioning systems in the coming decades. These fluids can be said to represent the third generation of fluorinated gases that have zero ODP and median and high GWP values. Currently, HFCs are largely used in commercial refrigeration and residential

• **Hydrofluoroolefins (HFOs):** The HFOs represent the fourth generation of fluorinated gases, with zero ODP and very low GWP values. It is already being used in automotive air conditioning systems in developed countries (the United States and Europe). They are fluids used in place of R-134a as they are suitable for high temperature applications and operate at similar

• **Natural refrigerants:** These fluids are generated through natural biochemical processes, so they pose no risk to the ozone layer and have very low or zero GWP indices. The most common natural fluids are R717 (ammonia), R744

Although the application of natural fluids in refrigeration systems is a worldwide trend, each fluid has its own characteristics and requires special care to be

• **Hydrocarbons:** They consist of a group of nontoxic gases with zero ODP and low GWP. They are environmentally friendly and have excellent thermodynamic properties, allowing good efficiency in similar or even better cooling

Because these refrigerant fluids are considered as flammable gas, hydrocarbon refrigeration systems must meet a number of safety guidelines. Typically, these gases are applied in small systems such as refrigerators or indirect systems and cooling secondary systems with other fluids (such as a CO2 cascade system). This

The most commonly used hydrocarbons in refrigeration are propane (R-290) and isobutane (R-600a). In addition to the GWP, the ozone depletion potential (ODP) is another parameter that compares the ozone layer depletion potential regarding the R-11 refrigerant, which is assigned the value 1. This value is compared

Refrigerants can be classified as simple, which are not mixed with other fluids such as R-22, R-134a, and R-32 and natural or blend fluids, which are mixtures of fluids, such as R-410A. The blend fluids may also be azeotropic or non-azeotropic. And this is another classification of refrigerants, which divides them into two broad

• **Azeotropic mixtures:** In these types of mixtures, the components cannot be distilled off. The mixture evaporates and condenses as if it were a single substance. Its properties are totally different from those of its components. As an example, we have CFC/HFC-500, HCFC/CFC-501, and HCFC/CFC-502. For example, HCFC/CFC-501 is a mixture of 75% HCFC-22 with 25% CFC-12 on a mass basis. Azeotropic mixtures causing ozone layer depletion were no longer

manufactured in 1996 in developed countries.

*DOI: http://dx.doi.org/10.5772/intechopen.89119*

air conditioning.

pressures.

implanted.

*Low-temperature Technologies*

x.Be easy to detect.

viii.Having compatibility with the lubricating oil of the compressor.

global warming, and should not attack the ozone layer.

xii.Not posing a danger to the environment.

index ranging from 0.6 to 1.

their ODP ranges from 0.02 to 0.1 [15, 17].

freezers).

xiii.Be commercially available at a reasonable cost.

ix.Having adequate compatibility with the materials of the refrigeration system.

xi.In case of leakage, it should not attack or spoil food, should not contribute to

The refrigerant groups available in the Brazilian market are divided into [15, 16]:

• **CFCs (chlorofluorocarbons):** They are refrigerant fluids whose molecule is formed by the element's chlorine, fluorine, and carbon, for example, the fluids R-11, R-12, R-113, R-114, R-115, and R-502, among others. The lifetime of CFCs in the atmosphere ranges from 60 to 540 years, causing high depletion of the ozone layer. Most CFCs have an ozone layer depletion potential (ODP)

CFCs were no longer manufactured by industrialized countries in January 1996 and, with some exceptions, by developing countries. These fluids feature high ODP and high GWP. According to the Montreal Protocol, in 1996 these gases were banned from developed countries, and in 2010 they should be banned from developing countries such as Brazil, but these gases are still found in old refrigeration and air conditioning systems. These fluids are used in automotive air conditioners, commercial refrigeration, and home refrigeration (refrigerators and

• **Hydrochlorofluorocarbons (HCFCs):** In these refrigerants some chlorine atoms are replaced by hydrogen, as an example of these fluids, have it R-22, R-123, R-401A, and R-4012A. These fluids are used in climate control systems, window air conditioners, split air conditioners, self-containers, cold rooms, etc.

These gases represent the second generation of fluorinated gases and were the main alternative to CFCs. They have lower ODP, but the GWP still between 1000 and 5000, so they are a little less harmful to the environment than their CFC predecessors, considering the ozone depletion. HCFCs are not fully halogenated like CFCs. The atmospheric lifetime of HCFCs ranges from 2 to 22 years, and therefore

Currently, in Brazil, HCFC-22 or (R-22) has been the most commonly used refrigerant in air conditioning systems since the early 1990s. HCFCs have been used as transition fluids, and their restriction on use and manufacturing started in 2004. According to the Montreal Protocol, the elimination of HCFCs in developed countries is expected by 2030 and in Brazil by 2040. Nevertheless, some countries are already well advanced on their elimination. In the European Union the use of HCFCs was terminated in January 2010 and may still be used until January 2015 in

• **Hydrofluorocarbons (HFCs):** In these fluids all chlorine atoms are replaced by hydrogen, for example, R-134a, R-404A, R-407C, R-410A, etc. These fluids

**82**

some specific cases.

are used in automotive air conditioning systems, commercial refrigeration and domestic refrigeration (refrigerators and freezers), etc.

As there are no chlorine atoms in HFCs refrigerants, they do not cause ozone layer depletion. HFCs are expected to become the most widely used in air conditioning systems in the coming decades. These fluids can be said to represent the third generation of fluorinated gases that have zero ODP and median and high GWP values. Currently, HFCs are largely used in commercial refrigeration and residential air conditioning.


Although the application of natural fluids in refrigeration systems is a worldwide trend, each fluid has its own characteristics and requires special care to be implanted.

• **Hydrocarbons:** They consist of a group of nontoxic gases with zero ODP and low GWP. They are environmentally friendly and have excellent thermodynamic properties, allowing good efficiency in similar or even better cooling systems than HCFC and HFC fluids.

Because these refrigerant fluids are considered as flammable gas, hydrocarbon refrigeration systems must meet a number of safety guidelines. Typically, these gases are applied in small systems such as refrigerators or indirect systems and cooling secondary systems with other fluids (such as a CO2 cascade system). This ensures a low risk of fire if a leak occurs.

The most commonly used hydrocarbons in refrigeration are propane (R-290) and isobutane (R-600a). In addition to the GWP, the ozone depletion potential (ODP) is another parameter that compares the ozone layer depletion potential regarding the R-11 refrigerant, which is assigned the value 1. This value is compared to other types of fluids.

Refrigerants can be classified as simple, which are not mixed with other fluids such as R-22, R-134a, and R-32 and natural or blend fluids, which are mixtures of fluids, such as R-410A. The blend fluids may also be azeotropic or non-azeotropic. And this is another classification of refrigerants, which divides them into two broad categories, which are:

• **Azeotropic mixtures:** In these types of mixtures, the components cannot be distilled off. The mixture evaporates and condenses as if it were a single substance. Its properties are totally different from those of its components. As an example, we have CFC/HFC-500, HCFC/CFC-501, and HCFC/CFC-502. For example, HCFC/CFC-501 is a mixture of 75% HCFC-22 with 25% CFC-12 on a mass basis. Azeotropic mixtures causing ozone layer depletion were no longer manufactured in 1996 in developed countries.

• **Zeotropic or non-azeotropic mixtures:** In a zeotropic mixture, its components are separated by distillation process. Thus, the mixture evaporates and condenses at different temperatures. Examples of such fluid types are R-400 and R-401A/B/C. Currently, these are the most promising alternative refrigerants for retrofit in air conditioning and refrigeration systems.

The CFCs and HCFCs are used worldwide in a variety of applications. By the middle of 1980, about 1/3 of CFC consumption occurred in the United States (USA). In 1985, the consumption of these fluids was around 278 tons.

These fluids served industrial sectors of insulating foams, automotive air conditioning, refrigeration and residential air conditioning, and commercial and industrial and other products. The CFC-expanded insulating foams have been widely used in industrial processes. Of this total, 19% was used in automotive air conditioning and 5% in new refrigeration and air conditioning systems. According to ABRAVA the percentage of halogenated refrigerant consumption is as follows: 77% HCFC-22, 10% CFC-11, and 10% CFC-12 [14].

Synthetic refrigerants (CFC, HCFC, HFC, and HFO) are considered safer, simpler to handle, and cheaper; however, most of them present some types of environmental risks. The presence of chlorine in the composition of most synthetic fluids is what makes them harmful to the ozone layer. Fluids that do not have chlorine in their composition are considered ecological but still favor the greenhouse effect, so the group of HFOs represents the promising generation of synthetic fluids.

The natural fluids such as CO2, ammonia, and hydrocarbons are considered more complex and have a higher cost. In addition, they are considered highly flammable, and care should be taken to install the systems that will receive these fluids. They are recommended for low load operations such as vending machines and have good applicability at any temperature.

Ammonia, used in ammonia fluid R-717, is considered toxic and slightly flammable, has good thermodynamic characteristics, and should be used in systems combined with glycol (chiller system), or CO2 (cascade system), for example [18].

The fluids with behavior of one substance, known as simple fluids, are easier to work because they have well defined properties, can be carried gaseous or liquid loads and in case of leaks, composition still the same in the installation, the only change will be in the volume. Azeotropic blend fluids such as R-22, despite being mixtures, have simple fluid characteristics. Non-azeotropic substances (such as R-404A, which has R-125, 44%, R-143 to 52%, R134 to 4%) have fluids with different boiling points and do not mix perfectly, so do not mix well. Thus, do not behave like simple fluid.

The use of these types of refrigerant implies extra care, as in the case of leaks, the composition of the leaked fluid and the composition of the remaining fluid may be unknown requiring a new charge. There is also the characteristic of glide temperature, where the evaporation temperature is not constant.

All these substances used in air conditioning and refrigeration systems are classified by safety groups as defined by AHSRAE. The classification considers the flammability and toxicity of each substance, as shown in **Table 2**, which presents the safety classification according to ASHAE [16]. Each refrigerant group requires a set of safety procedures for their use, installation, and disposal. The refrigerants found in the CFC, HCFC, and HFC categories are mostly classified in group A1 as non-flammable and of low toxicity. They are safe but environmentally aggressive fluids.

HFO refrigerants are less environmentally friendly but are classified in group A2L, i.e., there is a low risk of spreading flames in the event of a leak, and therefore require some caution and safety devices in equipment using these types of refrigerants.

**85**

*An Experimental Study of Synthetics and Natural Refrigerants Gases*

Natural fluids, while an alternative more environmentally friendly, require a lot of care, and their facilities must follow the safety guidelines defined for each application. Propane and isobutane hydrocarbons are classified as highly flammable (group A3) while ammonia as highly toxic and low flammability (group B2L). Although carbon dioxide falls within group A1, it is a choking gas, so your systems

High flammability A3 B3 Low flammability A2 B2

Non-flammable A1 B1

A2L B2L

Low toxicity High toxicity

In a Refrigeration system, the refrigerant is contained within the equipment,

When a coolant leak in a refrigeration system and air conditioning, depending on the design and the refrigerant charge amount used in the system, choking

Most leaks in the air conditioning and refrigeration systems are related to maintenance aspects, from the use of poorly maintained, deteriorated or even inadequate components and equipment as well as precarious labor that only acts

In the refrigeration, the word "retrofit" has been used to designate the adaptations that are made to equipment that works with CFCs so that they can work with alternative fluids (HCFCs, HFCs), making them efficient, modern, and economical. Another solution is the alternative fluid line, also called "blends," which is a good alternative for converting equipment that is operating in the field as it requires minimal changes to the original system, and in most cases no compressor replace-

**Table 3** shows a comparison of the ODP, GWP, and ASHRAE safety ratings of

In the Brazilian market, as shown in **Table 3**, it is observed that the replacement of refrigerant fluid R-22 (HCFC) with R-410A (HFC) is occurring; however, it is worth noting that this substitution does not alter the potential for global

In a direct comparison, R-134a refrigerant (tetrafluoroethane) has similar physical and thermodynamic properties to R-12, but it has lower ozone depletion potential (ODP) due to the absence of chlorine and the shorter lifetime in the atmosphere (16 years versus 120 years for R012). This fluid has a 90% reduction in greenhouse potential when compared to R-12. In addition, it is non-flammable and nontoxic, has high thermal and chemical stability, has compatibility with the materials used, and has adequate physical and thermodynamic properties. In addition, the R-134a refrigerant is free of chlorine and therefore has good compatibility with elastomers. One of the consequences of this change is that during the maintenance process of the air conditioning and refrigeration equipment, the R-22 fluid is released to

According to the Brazilian Ministry of Environment (MMA), the most commonly used refrigerant in cooling and air conditioning is HCFC-22, accounting for 82% of consumption [15, 19]. Considering the indicators shown in **Table 3** and the

must follow a series of precautions to ensure the safety of the installation.

there is no direct contact between users and the refrigerant.

problems may occur in people or product contamination.

when problems occur.

ment is required [19].

nature, without any kind of control.

some refrigerants.

warming.

*DOI: http://dx.doi.org/10.5772/intechopen.89119*

*Source: ASHRAE Fundamentals [16].*

*ASHAE safety classification.*

**Table 2.**


#### *An Experimental Study of Synthetics and Natural Refrigerants Gases DOI: http://dx.doi.org/10.5772/intechopen.89119*

#### **Table 2.**

*Low-temperature Technologies*

• **Zeotropic or non-azeotropic mixtures:** In a zeotropic mixture, its components are separated by distillation process. Thus, the mixture evaporates and condenses at different temperatures. Examples of such fluid types are R-400 and R-401A/B/C. Currently, these are the most promising alternative refriger-

The CFCs and HCFCs are used worldwide in a variety of applications. By the middle of 1980, about 1/3 of CFC consumption occurred in the United States

Synthetic refrigerants (CFC, HCFC, HFC, and HFO) are considered safer, simpler to handle, and cheaper; however, most of them present some types of environmental risks. The presence of chlorine in the composition of most synthetic fluids is what makes them harmful to the ozone layer. Fluids that do not have chlorine in their composition are considered ecological but still favor the greenhouse effect, so

the group of HFOs represents the promising generation of synthetic fluids.

perature, where the evaporation temperature is not constant.

The natural fluids such as CO2, ammonia, and hydrocarbons are considered more complex and have a higher cost. In addition, they are considered highly flammable, and care should be taken to install the systems that will receive these fluids. They are recommended for low load operations such as vending machines and have

Ammonia, used in ammonia fluid R-717, is considered toxic and slightly flammable, has good thermodynamic characteristics, and should be used in systems combined with glycol (chiller system), or CO2 (cascade system), for example [18]. The fluids with behavior of one substance, known as simple fluids, are easier to work because they have well defined properties, can be carried gaseous or liquid loads and in case of leaks, composition still the same in the installation, the only change will be in the volume. Azeotropic blend fluids such as R-22, despite being mixtures, have simple fluid characteristics. Non-azeotropic substances (such as R-404A, which has R-125, 44%, R-143 to 52%, R134 to 4%) have fluids with different boiling points and do not mix perfectly, so do not mix well. Thus, do not behave like simple fluid. The use of these types of refrigerant implies extra care, as in the case of leaks, the composition of the leaked fluid and the composition of the remaining fluid may be unknown requiring a new charge. There is also the characteristic of glide tem-

All these substances used in air conditioning and refrigeration systems are classified by safety groups as defined by AHSRAE. The classification considers the flammability and toxicity of each substance, as shown in **Table 2**, which presents the safety classification according to ASHAE [16]. Each refrigerant group requires a set of safety procedures for their use, installation, and disposal. The refrigerants found in the CFC, HCFC, and HFC categories are mostly classified in group A1 as non-flammable and of low toxicity. They are safe but environ-

HFO refrigerants are less environmentally friendly but are classified in group A2L, i.e., there is a low risk of spreading flames in the event of a leak, and therefore require some caution and safety devices in equipment using these types of

These fluids served industrial sectors of insulating foams, automotive air conditioning, refrigeration and residential air conditioning, and commercial and industrial and other products. The CFC-expanded insulating foams have been widely used in industrial processes. Of this total, 19% was used in automotive air conditioning and 5% in new refrigeration and air conditioning systems. According to ABRAVA the percentage of halogenated refrigerant consumption is as follows:

ants for retrofit in air conditioning and refrigeration systems.

(USA). In 1985, the consumption of these fluids was around 278 tons.

77% HCFC-22, 10% CFC-11, and 10% CFC-12 [14].

good applicability at any temperature.

**84**

refrigerants.

mentally aggressive fluids.

*ASHAE safety classification.*

Natural fluids, while an alternative more environmentally friendly, require a lot of care, and their facilities must follow the safety guidelines defined for each application. Propane and isobutane hydrocarbons are classified as highly flammable (group A3) while ammonia as highly toxic and low flammability (group B2L). Although carbon dioxide falls within group A1, it is a choking gas, so your systems must follow a series of precautions to ensure the safety of the installation.

In a Refrigeration system, the refrigerant is contained within the equipment, there is no direct contact between users and the refrigerant.

When a coolant leak in a refrigeration system and air conditioning, depending on the design and the refrigerant charge amount used in the system, choking problems may occur in people or product contamination.

Most leaks in the air conditioning and refrigeration systems are related to maintenance aspects, from the use of poorly maintained, deteriorated or even inadequate components and equipment as well as precarious labor that only acts when problems occur.

In the refrigeration, the word "retrofit" has been used to designate the adaptations that are made to equipment that works with CFCs so that they can work with alternative fluids (HCFCs, HFCs), making them efficient, modern, and economical. Another solution is the alternative fluid line, also called "blends," which is a good alternative for converting equipment that is operating in the field as it requires minimal changes to the original system, and in most cases no compressor replacement is required [19].

**Table 3** shows a comparison of the ODP, GWP, and ASHRAE safety ratings of some refrigerants.

In the Brazilian market, as shown in **Table 3**, it is observed that the replacement of refrigerant fluid R-22 (HCFC) with R-410A (HFC) is occurring; however, it is worth noting that this substitution does not alter the potential for global warming.

In a direct comparison, R-134a refrigerant (tetrafluoroethane) has similar physical and thermodynamic properties to R-12, but it has lower ozone depletion potential (ODP) due to the absence of chlorine and the shorter lifetime in the atmosphere (16 years versus 120 years for R012). This fluid has a 90% reduction in greenhouse potential when compared to R-12. In addition, it is non-flammable and nontoxic, has high thermal and chemical stability, has compatibility with the materials used, and has adequate physical and thermodynamic properties. In addition, the R-134a refrigerant is free of chlorine and therefore has good compatibility with elastomers. One of the consequences of this change is that during the maintenance process of the air conditioning and refrigeration equipment, the R-22 fluid is released to nature, without any kind of control.

According to the Brazilian Ministry of Environment (MMA), the most commonly used refrigerant in cooling and air conditioning is HCFC-22, accounting for 82% of consumption [15, 19]. Considering the indicators shown in **Table 3** and the


#### **Table 3.**

*Comparison of available refrigerants for air conditioning and refrigeration systems.*

properties listed above, it is important to realize that most refrigerants do not meet the requirements for commercial use in order to comply with Brazilian and worldwide legislation.

The scenario of replacing the R-22 in the refrigeration and air conditioning industry points to a number of alternative fluids. In this context, manufacturers in the refrigeration and air conditioning industry are looking for solutions that meet their goals without neglecting good performance.

According to ABRAVA [14], **Table 4** presents the suggestions of alternative fluids to the use of R-22 according to each application:

In a survey by the members of the UFPA Resfriar Project, in the metropolitan region of Belém do Pará, along with companies that work with the sale, installation, and maintenance of HVAC systems, more than 95% of people involved with the services did not have either training courses or were qualified to develop the services.

In Brazil, it is possible to observe that, in the practical activities, during the maintenance processes, the people qualified for the development of installation,

**87**

these acts.

warming.

**4. Test bench type chiller**

system has been described.

**4.1 Theoretical fundamentals**

*An Experimental Study of Synthetics and Natural Refrigerants Gases*

Air conditioners and heat pumps Residential/small commercial air

**Equipment types Usual application Main refrigerant** 

Multi-split systems Residential/commercial R-407C or R-410A Large air conditioning systems Commercial R-134a or R-410A Air condensing chillers Central systems R-134a or R-410A Water condensing chillers Central systems R-134a Commercial refrigeration Commercial R-134a, R-404A,

conditioning

Commercial R-410A

Industrial/transport R -134a or ammonia

Window air conditioners (WAC) Residential R-410A

**substitutes**

R-410A

R-410A, or R-507A

operation, and maintenance activities of air conditioning and refrigeration systems, called in Brazil as "refrigeration professional," are the people who, not necessarily, are technicians of maintenance of air conditioning and refrigeration

It was found that during the development of the analysis and maintenance services, these people either lack adequate equipment, such as a vacuum pump or a refrigerant recovery unit, or lack of knowledge, or because they could not afford to purchase such basic equipment and instruments required to perform the service and release the refrigerants from the equipment to the local environment. Besides that, they always have a recharge for normal system operation and, in many cases, do not have a basic analysis or concern about the consequences of

This common and uncontrolled practice releases thousands of kilograms of refrigerant fluids per year, to the environment, contributing significantly to global

In this topic, the theoretical foundations about vapor compression type cooling systems, with synthetic and natural fluids, necessary for the understanding about the experimental apparatus used are initially approached. After that, the experimental apparatus developed in the ClimatCont laboratory to simulate a chiller

Some scientific studies specifically dedicated to the comparison of natural fluids with the most common synthetic ones, such as R-22 fluid, have been carried out and published. The research conducted by Park and Jung's [20] related the replacement

systems and, in many cases, are called "curious".

*Alternative refrigerants for R-22 refrigerant according to your applications.*

*DOI: http://dx.doi.org/10.5772/intechopen.89119*

Hot and cold air conditioners (multi-split systems)

Industrial and transport

refrigeration

**Table 4.**

*Source: ABRAVA [14].*

*An Experimental Study of Synthetics and Natural Refrigerants Gases DOI: http://dx.doi.org/10.5772/intechopen.89119*


#### **Table 4.**

*Low-temperature Technologies*

R-502/CFC blend R-115 (51%), R-22

R-410a/AZ-20 R-32 (50%), R-125

R-507/AZ-50 R-125 (50%), R-143a

**CFCs**

**HCFCs**

**HFCs**

**HFOs**

**Natural refrigerants (NRs)**

*Source: ASHRAE Fundamentals [16].*

**86**

services.

wide legislation.

**Table 3.**

properties listed above, it is important to realize that most refrigerants do not meet the requirements for commercial use in order to comply with Brazilian and world-

**Number/name Formula ODP GWP ASHAE safety** 

R-11/trichlorofluoromethane CCl3F 1 4000 A1 R-12/dichlorodifluoromethane CCl2F2 1 8500 A1

R-22/chlorodifluoromethane CHClF2 0.055 1700 A1 R-123/dichlorotrifluoroethane C2HCl2F3 0.02 93 A1

R-32/difluoromethane CH2F2 0.0 650 A1 R-134a/tetrafluoroethane C2H2F4 0.0 1300 A1

R-1234yf C3H2F4 0.0 4 A2L R-1234ze C3H2F4 0.0 6 A2L R-218/perfluoropropane C3F8 0.0 7000 A2L

R-290/propane, Care 40 C3H8 0.0 ~5 A3 R-600a/isobutane, Care 10 C4H10 0.0 ~5 A3 R-717/ammonia NH3 0.0 <1 B2L R-718/water H2O 0.0 <1 A1

(50%)

(50%)

(49%)

**classification**

0.23 5590 A1

0.0 1730 A1

0.0 3300 A1

The scenario of replacing the R-22 in the refrigeration and air conditioning industry points to a number of alternative fluids. In this context, manufacturers in the refrigeration and air conditioning industry are looking for solutions that meet

According to ABRAVA [14], **Table 4** presents the suggestions of alternative

In a survey by the members of the UFPA Resfriar Project, in the metropolitan region of Belém do Pará, along with companies that work with the sale, installation, and maintenance of HVAC systems, more than 95% of people involved with the services did not have either training courses or were qualified to develop the

In Brazil, it is possible to observe that, in the practical activities, during the maintenance processes, the people qualified for the development of installation,

their goals without neglecting good performance.

fluids to the use of R-22 according to each application:

*Comparison of available refrigerants for air conditioning and refrigeration systems.*

*Alternative refrigerants for R-22 refrigerant according to your applications.*

operation, and maintenance activities of air conditioning and refrigeration systems, called in Brazil as "refrigeration professional," are the people who, not necessarily, are technicians of maintenance of air conditioning and refrigeration systems and, in many cases, are called "curious".

It was found that during the development of the analysis and maintenance services, these people either lack adequate equipment, such as a vacuum pump or a refrigerant recovery unit, or lack of knowledge, or because they could not afford to purchase such basic equipment and instruments required to perform the service and release the refrigerants from the equipment to the local environment. Besides that, they always have a recharge for normal system operation and, in many cases, do not have a basic analysis or concern about the consequences of these acts.

This common and uncontrolled practice releases thousands of kilograms of refrigerant fluids per year, to the environment, contributing significantly to global warming.
