Prior to 1850, a brilliant Australian Engineer, James Harrison invented the vapour compression refrigeration system by “closing the loop”. He was aware that when ether evaporated it made printing type set cold when used for cleaning. His invention collected the evaporated gas, compressed it, condensed it and fed it back as a liquid to be re-evaporated, thereby forming a closed loop. Refrigeration was born. By 1855, Harrison was manufacturing ice machines operating on ether in the closed refrigeration circuit, while the rest of the world were still cutting ice blocks from frozen rivers and lakes. In 1856, Harrison was awarded patent No. 747 for his invention.
In the 1860’s, ammonia started to be used in refrigeration as it was seen as a much safer alternative than ether. Ammonia quickly gained popularity and by 1900 it dominated the world of refrigeration as the refrigerant of choice. The ammonia domination remained through until the 1930’s when the first synthetic refrigerants known as CFC’s were introduced. CFC’s and subsequently HCFC’s and HFC’s then took over and dominated the commercial, domestic and transport refrigeration and air conditioning sectors, confining ammonia to the Industrial refrigeration world. Recent decades have seen the phasing out of the synthetic refrigerants in recognition of their extreme environmental damage. There has been a resurgence of the use of ammonia as one of three naturally occurring refrigerants attracting huge support worldwide, the other two being carbon dioxide and hydrocarbons.
From a thermal engineering point of view, ammonia is an excellent refrigerant achieving vapour compression, cycle efficiencies better than virtually all other refrigerants.