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Refrigeration
The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology Refrigeration can be considered an artificial, or human-made, cooling method. Refrigeration refers to the process by which energy, in the form of heat, is removed from a low-temperature medium and transferred to a high-temperature medium. This work of energy transfer is traditionally driven by mechanical means, but can also be driven by heat, magnetism, electricity, laser, or other means. Refrigeration has many applications, including household refrigerators, industrial freezers, cryogenics, and air conditioning. Heat pumps may use the heat output of the refrigeration process, and also may be designed to be reversible, but are otherwise similar to air conditi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refrigerator
A refrigerator, colloquially fridge, is a commercial and home appliance consisting of a thermal insulation, thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to its external environment so that its inside is cooled to a temperature below the room temperature. Refrigeration is an essential Food preservation, food storage technique around the world. The lower temperature lowers the reproduction rate of bacteria, so the refrigerator reduces the rate of Food spoilage, spoilage. A refrigerator maintains a temperature a few degrees above the freezing point of water. The optimal temperature range for perishable food storage is .Keep your fridge-freezer clean and ice-free ''BBC''. 30 April 2008 A similar device that maintains a temperature below the freezing point of water is called a freezer. The refrigerator replaced the icebox, which had been a common household appliance for almost a century and a half. The United ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freezer
A refrigerator, colloquially fridge, is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to its external environment so that its inside is cooled to a temperature below the room temperature. Refrigeration is an essential food storage technique around the world. The lower temperature lowers the reproduction rate of bacteria, so the refrigerator reduces the rate of spoilage. A refrigerator maintains a temperature a few degrees above the freezing point of water. The optimal temperature range for perishable food storage is .Keep your fridge-freezer clean and ice-free ''BBC''. 30 April 2008 A similar device that maintains a temperature below the freezing point of water is called a freezer. The refrigerator replaced the icebox, which had been a common household appliance for almost a century and a half. The United States Food and Drug Administration recommends tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Conditioning
Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling the humidity of internal air. Air conditioning can be achieved using a mechanical 'air conditioner' or alternatively a variety of other methods, including passive cooling or ventilative cooling. Air conditioning is a member of a family of systems and techniques that provide Heating, ventilation, and air conditioning, heating, ventilation, and air conditioning (HVAC). Heat pumps are similar in many ways to air conditioners, but use a reversing valve to allow them to both heat and also cool an enclosed space. Air conditioners, which typically use vapor-compression refrigeration, range in size from small units used within vehicles or single rooms to massive units that can cool large buildings. Air source heat pumps, which can be used for heat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refrigerator Car
A refrigerator car (or "reefer") is a refrigerated boxcar (U.S.), a piece of railroad rolling stock designed to carry perishable freight at specific temperatures. Refrigerator cars differ from simple insulated boxcars and ventilated boxcars (commonly used for transporting fruit), neither of which are fitted with cooling apparatus. Reefers can be ice- cooled, come equipped with any one of a variety of mechanical refrigeration systems, or utilize carbon dioxide (either as dry ice, or in liquid form) as a cooling agent. Milk cars (and other types of "express" reefers) may or may not include a cooling system, but are equipped with high-speed trucks and other modifications that allow them to travel with passenger trains. History Background: North America After the end of the American Civil War, Chicago, Illinois emerged as a major railway center for the distribution of livestock raised on the Great Plains to Eastern markets. Transporting the animals to market required herds to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryogenics
In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cryogenic” by accepting a threshold of 120 K (or –153 °C) to distinguish these terms from the conventional refrigeration. This is a logical dividing line, since the normal boiling points of the so-called permanent gases (such as helium, hydrogen, neon, nitrogen, oxygen, and normal air) lie below 120K while the Freon refrigerants, hydrocarbons, and other common refrigerants have boiling points above 120K. The U.S. National Institute of Standards and Technology considers the field of cryogenics as that involving temperatures below -153 Celsius (120K; -243.4 Fahrenheit) Discovery of superconducting materials with critical temperatures significantly above the boiling point of nitrogen has provided new interest in reliable, low cost me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Harvesting, Massachusetts, Early 1850s
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color. In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far away as the Oort cloud objects. Beyond the Solar System, it occurs as interstellar ice. It is abundant on Earth's surfaceparticularly in the polar regions and above the snow lineand, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes and aggregates from snow as glaciers and ice sheets. Ice exhibits at least eighteen phases ( packing geometries), depending on temperature and pressure. When water is cooled rapidly (quenching), up to three types of amorphous ice can form depending on its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooling
Cooling is removal of heat, usually resulting in a lower temperature and/or phase change. Temperature lowering achieved by any other means may also be called cooling.ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology The transfer of thermal energy may occur via thermal radiation, heat conduction or convection. Examples can be as simple as reducing temperature of a coffee. Devices *Coolant *Cooling towers, as used in large industrial plants and power stations * Daytime passive radiative cooler * Evaporative cooler *Heat exchanger *Heat pipe *Heat sink *HVAC (Heating, Ventilation and Air Conditioning) *Intercooler *Radiative cooling in Heat shields *Radiators in automobiles *Pumpable ice technology Pumpable ice technology (PIT) uses thin liquids, with the cooling capacity of ice. Pumpable ice is typically a slurry of ice crystals or particles ranging from 5 micrometers to 1 cm in diameter and transported in brine, seawater, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Harvesting
Ice cutting is a winter task of collecting surface ice from lakes and rivers for storage in ice houses and use or sale as a cooling method. Rare today, it was common (see ice trade) before the era of widespread mechanical refrigeration and air conditioning technology. The work was done as a winter chore by many farmers and as a winter occupation by icemen. Kept insulated, the ice was preserved for cold food storage during warm weather, either on the farm or for delivery to residential and commercial customers with ice boxes. A large ice trade existed in the 19th and early 20th centuries, until mechanical refrigeration displaced it. Ice harvesting generally involved waiting until approximately a foot of ice had built up on the water surface in the winter. The ice would then be cut with either a handsaw or a powered saw blade into long continuous strips and then cut into large individual blocks for transport by wagon back to the ice house. Because snow on top of the ice slows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Pump
A heat pump is a device that can heat a building (or part of a building) by transferring thermal energy from the outside using a refrigeration cycle. Many heat pumps can also operate in the opposite direction, cooling the building by removing heat from the enclosed space and rejecting it outside. Units that only provide cooling are called air conditioners. When in heating mode, a refrigerant at outside temperature is being compressed. As a result, the refrigerant becomes hot. This thermal energy can be transferred to an indoor unit. After being moved outdoors again, the refrigerant is decompressed — evaporated. It has lost some of its thermal energy and returns colder than the environment. It can now take up the surrounding energy from the air or from the ground before the process repeats. Compressors, fans, and pumps run with electric energy. Common types are air-source heat pumps, ground-source heat pumps, water-source heat pumps and exhaust air heat pumps. They are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Cutting
Ice cutting is a winter task of collecting surface ice from lakes and rivers for storage in ice houses and use or sale as a cooling method. Rare today, it was common (see ice trade) before the era of widespread mechanical refrigeration and air conditioning technology. The work was done as a winter chore by many farmers and as a winter occupation by icemen. Kept insulated, the ice was preserved for cold food storage during warm weather, either on the farm or for delivery to residential and commercial customers with ice boxes. A large ice trade existed in the 19th and early 20th centuries, until mechanical refrigeration displaced it. Ice harvesting generally involved waiting until approximately a foot of ice had built up on the water surface in the winter. The ice would then be cut with either a handsaw or a powered saw blade into long continuous strips and then cut into large individual blocks for transport by wagon back to the ice house. Because snow on top of the ice slows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiling Point
The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at low pressure has a lower boiling point than when that liquid is at atmospheric pressure. Because of this, water boils at under standard pressure at sea level, but at at altitude. For a given pressure, different liquids will boil at different temperatures. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, one atmosphere. At that temperature, the vapor pressure of the liquid becomes sufficient to overcome atmosph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It is commonly used as a solvent in laboratories and as a starting fluid for some engines. It was formerly used as a general anesthetic, until non-flammable drugs were developed, such as halothane. It has been used as a recreational drug to cause intoxication. Production Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
