3.1 Introduction and History of Refrigerants

Introduction

The Canadian government, as part of its international commitment to the Montreal Protocol, has eliminated the importation, exportation, and production of certain types of designated refrigerants and other ODS.

In Manitoba, designated refrigerants are divided into three classes:

  • Class 1 (CFCs)
  • Class 2 (HCFCs)
  • Class 3 (HFCs)

Manitoba, along with most other provinces and territories within Canada have mandated that designated refrigerants be recovered, reclaimed, reused, recycled or destroyed.

It is also recommended that all refrigerants, designated and non-designated (hydrocarbons), be treated as though they were designated.

The practices and procedures in this text are designed for use with all refrigerants.

History of Refrigerants

Refrigerants were developed to meet the needs of the mechanical refrigeration industry.

One of the first refrigerants ever used was water.

Water is a very effective refrigerant as it will absorb 970 BTU/lb. of heat.

By reducing water’s boiling point in a vacuum, it can provide cooling temperatures at 4.5°C.

The major disadvantage of water as a refrigerant and the reason why it is no longer in use is because of the amount of vacuum required to lower its boiling point (29” Hg).

To maintain this low vacuum, systems required a high degree of maintenance.

As the mechanical refrigeration industry grew and the need for efficient refrigerants increased, ammonia and carbon dioxide were primarily used.

However, due to their unstable nature, in addition to several fatal accidents involving these substances, their use was discontinued.

The development of the automatic refrigerator created a need for newer, stable refrigerants such as sulphur dioxide and methyl chloride.

Sulphur dioxide and methyl chloride were stable, non-explosive refrigerants, but are no longer used today because of their toxicity.

Later on, CFCs and more recently HCFCs and HFCs became the most common types of refrigerants in use today.

Of all the early refrigerants developed, only ammonia remains as the choice refrigerant in the manufacturing of ice used in arenas and ice-making plants.

In order to understand the differences in refrigerants, and more importantly, what makes them different, we must study the chemical composition of the refrigerants themselves.