Principles of refrigeration (ingles)

Principles of refrigeration

Introduction to the cooling¨ The cooling helps to raise the living standards of people of all countries. Advances in refrigeration in subsequent years are the result of joint work in which the technicians, the staff made, engineers, scientists and others have contributed their skills and knowledge.
        The grounds on which the construction of new substances and materials are provided by science. This knowledge is applied to the field of refrigeration by those who design, manufacture, install and maintain refrigeration equipment. After it has become useful dare planned subsequent research, development and practical application.
        Applying the principle of cooling does not have limits. The example most common and easily recognized that mind is in food preservation. Almost all products are in the house, farm, trade, industry or in laboratories are affected somewhat by cooling is essential to echo in modern life.

Brief historical sketch of the cold produced by man ¨ ¨
        The history of ice ages dating as far back as historical records. While the caveman from the stone age knew what it was ice, I had no idea about the use of it to preserve food. Thousands of years later, the Chinese learned that the ice improved the taste of beverages. Then, cut ice in the winter, packed with straw and sold during the summer.
        The ancient Egyptians discovered that they could cool the water depositing in porous jars placed on the roofs of houses to bet the sun. The breezes of the night evaporate the moisture that has seeped girders pitcher walls, cooling the water contained therein. The Greeks and Romans transported snow from mountain peaks to a conical pits that covered with straw and branches, then covered with a thatched roof. With the progress of civilization people hapredio as cool drinks and food to enjoy better. This knowledge will increase the use of ice and snow.

First experiments in food preservation.
            Some early experiments were recorded on the conservation of food goes back to 1626, when Francis Bacon attempted to keep a chicken filling it with snow. In 1683 Anton Van leeuwenhock uncovered an entire scientific world. The Dutch invented a microscope and discovered that a crystal clear water has millions of living organisms. Today this is known as microbes. The scientists studied these microbes and found that he had held his rapid multiplication in the heat and humidity, such as providing food materials. This multiplication of microbes soon recognized as the main elements, in contrast, at temperatures of 50 ° F (10 ° C) or lower, the same types of microbes multiplied at all. Through these scientific studies were hoisted clear that fresh food can be preserved at a temperature of 10 ° C or less. Then it was possible to preserve food dehydrating, by smoking, salting or by cooling.
               As he had little knowledge on how to produce temperatures low enough to freeze the water, the ice was transported from their natural sources on boats till the main cities.

Experiments with machines for making ice.
               One of the first patent (1834) for a machine for making ice was practiced which has awarded Jacob Perkins, an American engineer who radiated in London. These machines were used successfully in meatpacking plants. During 50 years there were ice machines in the United States, France and Germany. During this period we requested records from about 3 000 patents on the cooling system in the United States
               While making progress in the production of ice by artificial means, most people preferred the natural ice, believing the artificial ice was unsafe.
               With time expired this superstition because: ce artificial ice produced using water more pure than that usually found in lakes and ponds, could be made when needed, and it was not necessary to store for long periods of time. Therefore, to the late nineteenth century, ice and refrigeration became common objects in the American home.
            One factor that contributed greatly to the further development of reliable refrigeration equipment was the availability of cheap electric power and the development of small electric motor. Parallel to these advances, scientists kept constant research on the truths to the cause and effect of which comprises most of the cooling process. ¨



Book: Principles of refrigeration.Authors: R. Warren Marsh and C. Tomas OlivoEditorial: Diana.