If we don't have refrigerator, hoe do you preserve food?(For example meat and fish) I think maybe we can't preserve foods without refrigeration.
Refrigerator preserves food freshly, It's important for us,I think. Because we can always eat fresh food and if it remained, we would be able to preserve to use refrigerator. And we can enjoy eating food that are from another country. refrigerator makes it possible. Before mecanical refrigerator systems were intoroduced, people cooled their food with ice and snow, either found locally or brought down from the mountains. Tha firast cellars were holes dug into the ground and lined with wood or straw and packed with snow and ice. Thia was the only means of refrigerator for most of history.
( By the way ,in Japan , long time ago ice was very precious. It's difficult to preserve ice. Just VIP(like lord ship)enjoyed eating ice.)
Refrigeration is the process of removing heat from an enclosed space, or from a substance, to lower its temperature. A refrigerator uses the evaporation of a liquid , or refrigerant, used in a refrigerator evaporates at an extremely low temperature , creating freezing tempertures inside the refrigerator. It's all based on the following physics:Liquid is rapidly vaporized,
the quickly expanding vapor requires kinetic energy and draws the energy needed from the immediate area-Which loses energy and becomes cooler. Cooking caused by the rapid expansion of gases is the primary means of refrigeration today.
The first known artificial refrigeration was demonstrated by William Cullen at the University of Slasgow in 1748. However, he did not use his discovery for any practical purpose. In 1805 An American inventor, Oliver Evans designed the first practical refrigerating machine was built by Jacob Perkins in 1834
It used ether in a vapor compression cycle. An American physician,Jhon Gorrie, built a refrigerator based on Oliver Evans' desigh in 1844 to make ice to cool the air for his yellow fever patients. German engineer Carl von Linden,patented not a refrigerator but the process of liquifying gas in 1876 that is part of basic refrigeration technology.
And then refrigeration have been improved more than before . In future , many new refrigerator will be created,I think.
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Submitted by yuki echigo on Fri, 03/03/2006 - 12:18.