THE HISTORY OF AMMONIA REFRIGERATION

MECHANICAL REFRIGERATION: THE RESEARCH BEGINS

The development of a thermometer by Galilei Galileo in 1597 marked the beginning of 300 years of research that led eventually to the modern mechanical refrigeration system. Early highlights of these experiments include the development of the standardized thermometer scale in 1709 by instrument maker Gabriel Daniel Fahrenheit and the isolation of ammonia, oxygen and carbon dioxide gases in 1773 by Englishman Joseph Priestly. One of the phenomena observed by the "natural philosophers" of the 18th century was the ability of volatile liquids such as ether to freeze water when allowed to evaporate while in contact with water. This observation combined with Englishman Michael Faraday's successful liquefication of ammonia and carbon dioxide gas by means of pressure, formed the basis for the refrigeration research of the 19th century. Most of this work took place in Europe and especially in England and France. The United States, with its abundance of harvested ice, complacently ignored most refrigeration research during this time. Two Americans however, did make worthwhile contributions.

In 1834 Jacob Perkins, an American living in England, built the first vapor compression machine which actually worked. Although his achievement was not mentioned in print for nearly 50 years, Perkins' machine, which was charged with ether, employed the four principal parts used in every compression installation to this day: a compressor, a condenser, an expansion valve and an evaporator. Dr. John Gorrie is credited with the first ice machine patented in the United States in 1851. The first public demonstration of his machine occurred in Apalachicola, Florida, on Bastille Day 1850 at a party held by a French cotton buyer, Monsier Rosan. Rosan, a personal friend of Gorrie, had made a wager with other cotton buyers that there would indeed be iced champagne in spite of the delayed arrival of the ice shipment from the North. Rosan won the wager with several pounds of ice from Gorrie's new machine, which used the rapid expansion of compressed air in the presence of water to create the ice.
Unfortunately Gorrie never was able to build a large version of his machine because of the rumored manipulations of the northern ice merchants.

MECHANICAL REFRIGERATION THREE, BASIC SYSTEMS

In the early years of the refrigeration industry the three basic refrigeration techniques were vapor absorption, similar to that perfected by the Carre brothers; Cold-air systems, along the lines of Gorrie's device, and Vapor compression systems, which eventually became the standard for the refrigeration industry.

For the most part refrigeration has changed little since the early 1900's, relying on fluid refrigeration in a closed cycle of evaporation, compression and condensation. Most of the work this century has been spent on refining the details of the system, seeking the most efficient refrigerant, developing better compressors, and working out the most efficient arrangement of components and pressures for the desired operating temperatures.

Refrigerants used in the early vapor compression machines included ammonia, sulfuric ether, carbon dioxide, sulfur dioxide, methyl chloride and some hydrocarbons. In the 1930's and 1940's the halocarbon refrigerants (commonly known by such trade names as "Freon, "Genetron," "Isotron," etc.) were developed, giving the industry a strong push into the household market because of their suitability for use with small horsepower motors. The past 50 years have seen the refrigerator move from luxury to necessity. The entire food distribution chain has become dependent upon refrigeration, from the farmer to the shipper to the processor to the supermarket to the home. It is a miracle of modern technology that has been over 300 years in the making. And playing a large part in the past and the present of mechanical refrigeration is the industrial refrigerant ammonia.

Available in: 
http://www.nh3tech.org/n3.html. Adapted and illustrated to be posted by Leopoldo Costa.