Category Archives for Refrigeration

Refrigerant Replacements and the Atmosphere

Refrigerants such as ammonia are used for low-temperature systems. These include food and process cooling, ice rinks, and so forth. Propane has been used for some special applications. Now that chlorinated hydrocarbons have been determined to be harmful to the … Continue reading

05. January 2011 by admin
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Refrigeration Capacity

Refrigeration machines are rated in tons of refrigeration. This rating indicates the size and ability to produce cooling energy in a given period. One ton of refrigeration has cooling energy equal to that produced by 1 ton of ice melting … Continue reading

05. January 2011 by admin
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Basic Refrigeration Cycle

A substance changes state when the inherent amount of heat is varied. Ice is water in a solid state and steam is a vapor state of water. A solid is changed to a liquid and a liquid to a vapor … Continue reading

05. January 2011 by admin
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Refrigeration from Vaporization

The perspiration on your body evaporates and cools your body. Water kept in a porous container is cooled on a hot day. The water seeps from the inside. There is a small amount of water on the outside surface. The … Continue reading

05. January 2011 by admin
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Latent Heat

The heat required to change the state of a substance without changing its temperature is called its latent heat, or hidden heat. Theoretically, any substance can be a gas, liquid, or solid, depending on its temperature and pressure. It takes … Continue reading

05. January 2011 by admin
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Heat Content

Every substance theoretically contains an amount of heat equal to the heat energy required to raise its temperature from absolute zero to its temperature at a given time. This is referred to as heat content, which consists of sensible heat … Continue reading

05. January 2011 by admin
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Specific Heat

Every substance has a characteristic called specific heat. This is the measure of the temperature change in a substance when a given amount of heat is applied to it. One Btu (British thermal unit) is the amount of heat required … Continue reading

05. January 2011 by admin
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Temperature and Heat

The production of excess heat in a system will cause problems. Normally, matter expands when heated. This is the principle of thermal expansion. The linear dimensions increase, as does the volume. Removing heat from a substance causes it to contract … Continue reading

05. January 2011 by admin
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Atmospheric Pressure

The layer of air that surrounds the earth is several miles deep. The weight of the air above exerts pressure in all directions. This pressure is called atmospheric pressure. Atmospheric pressure at sea level is 14.7 psi, which converts to … Continue reading

05. January 2011 by admin
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Pressure-Indicating Device

Pressure-indicating devices are most important in the refrigeration field. It is necessary to know the pressures in certain parts of a system to locate trouble spots. The diaphragm is a flexible sheet of material held firmly around its perimeter so … Continue reading

05. January 2011 by admin
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