**2.1 Montreal Protocol**

*Low-temperature Technologies*

no ozone-depleting chemical component. But, if an approximately 10 kg of this refrigerant leaks into the atmosphere, the contribution to the greenhouse effect/ global warming will be equivalent to the emission of 40 tons of CO2 [1, 2].

In Brazil, all refrigerants, currently available on the market, are the basis of HCFC and HFC, but these fluids have their days counted for their discontinuation given the contribution to environmental pollution and the action of the Montreal and Kyoto Protocols that made societies aware of the harmful action of these

Due to these prohibitions imposed by world laws and protocols, the air conditioning and refrigeration market in Brazil aims solutions for the use of refrigerants, which vary between synthetic fluids that has a high value of global warming potential (GWP) and natural fluids, which has a lower value of global warming potential (GWP) than the synthetic ones. However, natural fluids have some impasses that are directly related to their composition, such as ammonia, which has excellent thermodynamic qualities, but it is a highly toxic fluid. The CO2 itself is another fluid that can be used in refrigeration systems, but as a downside, it works under high pressures, close to 100 bar. The hydrocarbon refrigerants, which are better known as R-290 and R-600a, are also excellent thermodynamic fluids, but these fluids are highly flammable and have their maximum amount to be applied to limited climate

In order to encourage the use of natural fluids in air conditioning and refrigeration systems, some laws and protocols have been created in the world to regulate, standardize, and inform mainly about safety issues related to the use of these types of refrigerants [4–6, 11]. From the point of view of use, there are scholarly works in air conditioning and refrigeration systems produced by companies that already work with some natural fluids and have great yields, both on the issue of capacity

The present work intends to develop a test bench so that reliable data on synthetic and natural fluids can be obtained. In the experimental stage, the refrigerants R-22 and R-290 were used. Nevertheless, in the simulation stage, some data were taken of Danfoss software in order to evaluate the thermodynamic, psychometric, and electric parameters, the ozone depletion potential (ODP), the GWP, the working pressure limits, and the local conditions. Hence, it has become possible to indicate the ideal fluid that should operate in a safe condition and with less aggres-

With the discoveries of the harmful effects of synthetic refrigerants, various organizations and institutions around the world have begun to work together to develop methods for control and to standardize and also to develop some kind of awareness about the use of these refrigerants as a working fluid in refrigeration and

Protocols were created first to fight the fluids that negatively affect the ozone

layer [1] and later to fight against the use of synthetic fluids, which are massive contributors to the greenhouse effect. Since the 1970s, some scientists have proven that there is a direct relationship between ozone depletion and the use of CFC (fluorine and chlorine-based hydrocarbons) compounds by industry, not only as refrigerants fluids but as aerosol propellants and foam blowing agents. According to photochemical reaction models involving ultraviolet irradiation, the depletion of the ozone layer is the result of a chain effect promoted by chlorine

and cooling efficiency, as the issue of energy consumption [12, 13].

products when released into the local environment [1–3].

systems for security reasons [4–10].

sive potential to the environment.

**2. Refrigerant legislation**

air conditioning systems.

(or bromine) atoms [2].

**78**

The Montreal Protocol is an international agreement developed by the United Nations, focusing on the environment. This protocol aims at the gradual reduction to the full transition of synthetic fluids with high ozone layer depletion potential by other types of environmentally friendly refrigerants. Since its inception in 1987, data collection through 2014 indicates that, with the Montreal Protocol, it has been possible to reduce the supply of ozone-depleting fluids by 98%, as most of this amount was used in cooling and air conditioning systems [1]. In European countries, in October 2016, HFC-lowering steps were agreed and became part of the Montreal Protocol, which entered into force on January 2019, pending ratification by 20 states, which appears to be a formality at the moment.

In the Montreal Protocol, in addition to the mechanisms for the gradual reduction and elimination of refrigerant use discussed above, many governments are applying tax measures to reduce the consumption of high potential global warming refrigerants, such as the creation of weighted taxes according to potential for the use of these products.

The production and use of HFCs such as R-32, R-125, R-134a, and R-143A and their mixtures (R-404, R-407C and R-410A) are not regulated by the Montreal Protocol but must be country-specific regulations made individually, so countries such as Spain, Denmark, Norway, and Sweden have imposed taxes on the use of HFCs in their air conditioning and refrigeration systems to reduce their use and control.

## **2.2 Kyoto Protocol**

Like the Montreal Protocol, the Kyoto Protocol is an international agreement, managed by the United Nations, that seeks to reduce pollutant emissions into the atmosphere. It is known that the last 150 years of industrial activities related to developed countries generated an increase in emissions and strengthening the greenhouse effect [2].

This protocol was prepared in Kyoto, Japan, in 1997 and, after adjustments, began to be implemented in 2005 and had its first stage, known as the first period, accounted for between 2001 and 2012. During that period 37 countries industrialized, and the European community have if pledged to reduce pollutant emissions by 5% compared to the 1990s. In the second period, in 2012 there was a meeting between the leaders of the countries that signed the Kyoto Protocol and the United Nations. At this meeting it was agreed that between 2013 and 2020 countries would continue to work on reducing emissions by 18% of the values stipulated in the 1990s [2].

#### **2.3 F-gas regulation**

The 517/2014 Law of the European Parliament and of the Council became known as regulating the use of fluorine-containing gases, known as F-gas, with the main objective of reducing emissions of gases with high potential for the destruction of the ozone layer, because they contribute to the greenhouse effect. Brazil is a signatory to this Law, which defines the rules on storage, recovery of synthetic fluids, as well as conditioning the trade of equipment and the refrigerants themselves in use in the Brazilian territory and also sets the practical limits on the use of F-gas in Brazil [3–5].

The first highlight of 517/2014 Law is the prohibition of the intentional release of any amount of F-gas into the atmosphere; however, it does not cite any criminal implication on anyone caught doing the act of this way.


#### **Table 1.**

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

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 checked every 3 months.

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

**Table 1** shows some air conditioning and refrigeration equipment with their respective prohibition dates for their refrigerants.

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

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:


**81**

*An Experimental Study of Synthetics and Natural Refrigerants Gases*

of new products from the refrigerant recovered.

reuse. It is to remove some contaminants like oil, water, and oleic and hydrochloric acids that can be found in system. In this process, the cooling fluid is

• **Reuse:** Reprocessing of the refrigerant, involving the manufacturing processes

• **Repair:** Restoration of equipment, for some reason, has lost its tightness, and this has resulted in the release of the working fluid to the atmosphere.

• **Leak detection system:** Mechanical or electronic equipment that allows to

• **Destination:** Currently in Brazil there are regeneration plants capable of receiving refrigerants to be reused within the standards required by law.

In underdeveloped countries, such as Brazil, despite the knowledge of the mechanism of ozone layer depletion and the creation of specific legislations to address the issue, there is still no concern with the use and disposal of F-gases, which makes it difficult to meet the dates stipulated by 517/2014 Law [5].

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.

conditioning and refrigeration systems, the most important are [15]:

v.Having small specific volume (causing less compressor work).

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

Among the various properties that a refrigerant should include for use in air

ii.High chemical stability when operating within the system and low chemical

vii.Evaporate at pressures above atmospheric (in case leakage air will not enter

identify possible leakage points in the system components [14].

distilled, filtered, then condensed, and finally, bottled [5, 14].

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

**3. Refrigerants**

273.16 K (0°C) without crystallizing.

i.Favorable thermodynamic properties.

vi.Having high latent heat of vaporization.

the system avoiding the risk of explosions).

stability outside the system.

iii.Nontoxic.

iv.Non-flammable.

reuse. It is to remove some contaminants like oil, water, and oleic and hydrochloric acids that can be found in system. In this process, the cooling fluid is distilled, filtered, then condensed, and finally, bottled [5, 14].


In underdeveloped countries, such as Brazil, despite the knowledge of the mechanism of ozone layer depletion and the creation of specific legislations to address the issue, there is still no concern with the use and disposal of F-gases, which makes it difficult to meet the dates stipulated by 517/2014 Law [5].
