This exhibit deals with the advent and history of the modern day mechanical refrigerator and how it works. The idea of modern refrigeration is very old, dating back to the mid-1850s when an American physician by the name of John Gorrie discovered the process by trying to lower the temperature of fever patients by trying to cool hospital rooms (1). Near the same time in Great Britain a patent was issued for "freezing food by immersion in an ice and salt brine." (1) The idea of refrigeration, however, is one that dates back to Greek and Roman times when the wealthy citizens owned snow cellars, holes dug into the ground and insulated with straw and wood. The ancient Indians and Egyptians had also devised ways to store ice by using the evaporative cooling ideas.

During the time when people like Gorrie were experimenting with refrigeration techniques, others around the world were trying to form better ways to store food stuffs. One of these people was Ferdinand Carre. He developed what is believed to be the first refrigerator. He used the evaporation technique to cool to the desired level. The refrigerant, or the stuff that is evaporated, was ammonia. So, using these ideas, the foundations for the modern day refrigerators had been laid. (1)

The modern refrigeration system is known as mechanical refrigeration. It was brought around during the early 1900s when many name brands emerged, including Kelvinator, General Electric and Westinghouse. Each of these companies boasted higher efficiency and lower cost. The mechanism behind the refrigeration was, however, pretty much the same. Here is a basic overview of how the mechanical refrigerator works and then we will discuss each item in detail. The basic steps in the mechanical refrigerator are as follows:

1) the refrigerant is circulated to achieve constant cooling
2) a constant supply of energy is needed to keep the system going, which works indefinitely if provided with energy.

Mechanical refrigerators come in two types. Ones that use the compression method to achieve cooling and ones that use the absorption method. The domestic refrigerators, those of interest to us, use the compression method to achieve cooling. The compression method requires four elements in its refrigeration cycle: the condenser, compressor, the expansion valve, and the evaporator. The process by which the mechanical vapor-compression refrigerator works is quite simple. The role of the evaporator is to boil the liquid refrigerant at a low temperature to produce cooling. The compressor is needed to raise the temperature and the pressure of the gaseous refrigerant. The heat is released through the condenser to the environment. The role of the expansion valve is to allow the liquid to expand from the high pressure level in the condenser to the low-pressure level in the evaporator. (2) In the domestic refrigeration, the evaporator, also known as the freezer, is always placed in an insulated space. So that the temperature inside the freezer can be controlled, the motor operating the compressor uses a thermostatic switch, which turns on and off depending on the specified temperature. (3) The refrigerant is a liquid substance that is recycled indefinitely as long as the power supply is provided. The liquid used has changed over the years has changed and these days it is usually a synthetic chloroflourocarbon called dichlorodiflouromethane, also known as refrigerant-12. Ammonia, freon and solutions of sodium or calcium chloride in water are also commonly used. (2) Energy source that is needed can be provided by two methods - gas power and electric power. For more information on these power systems please refer to gas model refrigerators and to electric model refrigerators.

Mechanical type of refrigerators were introduced during the 1920s and soon became very popular. They were easy to operate and required less work to clean compared to the ice boxes of before. They also acted as status symbols since not everyone was fortunate enough to own one. Most popular magazines, like Scientific American, Journal of Home Economics, Ladies Home Journal and many more, had articles on how to rate the refrigerators, what to look for when deciding to buy one, comparisons between the ice boxes and the new technology, and general articles dealing with what to expect when one purchases a mechanical refrigerator. One article from The Ladies' Home Journal from August 1919 had an interesting article about new technology. The article dealt with informing people about this brand new technology that makes ice without the use of ice. (4) Another article in the May 1921 issue of House and Garden offered tips on buying the right refrigerator - whether a mechanical would be suitable or would the old ice box suffice. (5) Both articles seemed to be written with great enthusiasm for the new technology. The article in The Ladies' Home Journal was written by a member for the Society for Electrical Development. This shows that many people were for the advancement of technology. This seems absurd to say, but not everyone was always willing to experiment with new technology. A good example is the lead character in J. D. Salingers popular novel Catcher in the Rye, Holden Caulfield. Holden is very cautious about the advent of new technology and suspects that people are becoming "phony" by buying into all this rapid industrialization.

Refrigerators were an important advancement in technology. They allowed foodstuffs to be transported over long distances without spoilage and thus increased trade and demand as well. They were also important to the economy since all this trade was taking place and it created opportunities for entreprenuership.