**7. Application of hydrocarbons as a refrigerant in commercial refrigeration systems**

Worldwide attempts are being made to eliminate the use of Chlorofluorocarbons (CFCs) because chlorine released from CFCs migrates to the stratosphere and destroys the stratospheric ozone layer. An international treaty known as Montreal Protocol was formed to regulate the production and trade of ozonedepleting substances. Sultanate of Oman is one among the signatories of the Montreal Protocol. During July 2003 a workshop was organized by Ministry of Regional Municipalities, Environment & Water Resources in collaboration with the UNIDO and UNEP at Muscat to train the trainers to phase out the CFCs in Sultanate of Oman. The author was also one of the participants of the workshop. After the workshop it is felt to review the available literature of the various refrigerants, especially hydrocarbons, as alternative to CFCs and hence this article. This article is primarily intended to provide a brief summary about completed /going on works during the last toe decades to use hydrocarbon as refrigerants in commercial refrigeration systems.

Among the commonly used CFCs, **dichlorodifluoromethane** (CFC-12) is one of the most widely used refrigerants in various applications such as Domestic Refrigerators, Bottle, Coolers, Deep Freezers, Water Coolers, and Mobile Air Conditioners etc. The excellent characteristics of CFC – 12 have lead to the development of highly efficient and reliable compressors and other refrigeration system components. Studies have shown that these refrigeration appliances give satisfactory performances for approximately 15 to 20 years. This high degree of reliability has caused the consumers to expect long services from these appliances in general. This necessitates extensive evaluation of alternative refrigerants before adopting them for commercial use. **The ideal substitute for CFC-12 should be non-toxic, nonflammable, chemically stable, compatible with refrigeration system materials and lubricants and have transport and thermodynamic properties similar to or better than CFC-12.** In addition, the ideal substitute should have zero Ozone Depleting Potential **(ODP**) and low Global Warming Potential (**GWP).** However, there is no such single substance, which possesses all these properties.

Though, the CFCs were characterized in 1890, but the development of fluorocarbon refrigerants was announced in 1930. Since then CFCs never looked back. Some of the historical highlights in the progress of refrigeration and the development of refrigerants are outlined in **Table 5**.

The prevalent refrigerants and refrigerant mixtures from halogenated hydrocarbon family in use are R-11, R-12, R-13, R-14, R-22, R-113, R-114, R-500 and R-502. In developed countries various steps have been already taken to control the use of ozone depleting refrigerants**.** In developing countries conversion from CFCs to alternatives is still a major issue.


**Table 5.** *Historical development of refrigerants.*

### *Refrigerant Mixtures DOI: http://dx.doi.org/10.5772/intechopen.99024*

As per the recent guidelines from the Environment Protection Agency USA, phasing down of HFCs and manufacturing of alternate refrigerants to CFCs and HFCs is the most significant environment policy to be practiced globally [13].

Montreal Protocol asks for abandoning the use and production of ODS in phased manner. It currently has the following control schedules for chemicals used as refrigerants:


The Montreal Protocol does not address non-ozone depleting chemicals According to Mc Linden over thirty years of research and development will be required to arrive at and maintain the family of refrigerants which are being used today.

Global action plans and the action plans to reduce the use and step by step phasing out of HFC type refrigernats was agreed by all the countries under the 2015, Paris amendment. In the year 2016, in Kigali, Ruwanda, around 197 countries had accepted for an amendment for the phasing down of HFC type refrigerant which was recommended by the Montreal Protocol. Phasing down of HFC type refrigerants has to be completely executed within the next 30 years [13].
