Refrigerator

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A refrigerator (ordinary language refrigerator , or refrigeratorfreezer in the UK) is a popular household tool consisting of thermally insulated compartments and heat pumps (mechanical, electronic or chemical) that transfers heat from the inside of the refrigerator to its external environment so that the interior of the refrigerator is cooled to a temperature below room temperature. Refrigeration is an important food storage technique in developed countries. Lower temperatures lower the rate of bacterial reproduction, so the refrigerator reduces the rate of decay. The fridge maintains a temperature a few degrees above the freezing point of water. The optimal temperature range for the storage of perishable foods is 3 to 5 Â ° C (37 to 41 Â ° F). A similar device that maintains a temperature below the freezing point of water is called freezer . Refrigerators replace the refrigerator, which has been a common household appliance for almost a century and a half. For this reason, refrigerators are sometimes referred to as refrigerators in the use of the American language.

The first cooling system for food involved using ice. Artificial refrigeration began in the mid-1750s, and was developed in the early 1800s. In 1834, the first vapor compression cooling system was built. The first commercial ice-creamer machine was invented in 1854. In 1913, a refrigerator for home use was created. In 1923, Frigidaire introduced the first independent unit. The introduction of Freon in the 1920s expanded the refrigerator market during the 1930s. Home freezers as separate compartments (bigger than required for ice cubes) were introduced in 1940. Frozen food, formerly luxury goods, became commonplace.

Freezer units are used in household and in industry and trade. Commercial refrigerators and freezer units were used for nearly 40 years before the public house model. The freezer-on-top-and-refrigerator-on-bottom style has been the basic style since the 1940s, until the modern refrigerators broke the trend. The vapor compression cycle is used in most household appliances, refrigerator freezers and freezers. Newer refrigerators may include automatic melting of ice, cold water, and ice from a dispenser at the door.

Refrigerators and domestic freezers for food storage are made in various sizes. Among the smallest is the 4 L Peltier refrigerator that is advertised as being able to accommodate 6 cans of beer. Large domestic refrigerators stand as tall as people and may be about 1 m wide with a capacity of 600 Â ° C. Refrigerators and freezers may be free standing, or built in the kitchen. Refrigerators allow modern households to keep fresh food longer than ever. Freezers allow people to buy large amounts of food and eat it in their spare time, and large purchases save money.

Video Refrigerator

History

Cooling technology

Prior to the invention of refrigerators, ice houses were used to provide cool storage for most of the year. Placed near freshwater lakes or packed with snow and ice during the winter, they were once very common. Natural ingredients are still used to cool food today. On the slopes, runoff from melting snow is an easy way to cool drinks, and during winter you can keep fresh milk longer by just keeping it outdoors. The word "fridge" was used at least in the early 17th century

The history of artificial refrigeration began when Scottish professor William Cullen designed a small cooling machine in 1755. Cullen used a pump to create a vacuum partly above the diethyl ether container, which was then boiled, absorbing heat from the surrounding air. The experiment even created a small amount of ice, but did not have any practical application at that time.

In 1805, the American inventor Oliver Evans described a closed-vapor compression cooling cycle for ice production by ether under vacuum. In 1820, British scientist Michael Faraday liquefied ammonia and other gases using high pressure and low temperatures, and in 1834, an American expatriate in England, Jacob Perkins, built the first functioning vapor compression refrigeration system. It is a closed cycle device that can operate continuously. A similar effort was made in 1842, by American physician John Gorrie, who built the working prototype, but it was a commercial failure. The American engineer, Alexander Twining, issued a British patent in 1850 for a vapor compression system using ether.

The first practical steam compression refrigeration system was built by James Harrison, an Australian citizen of Scottish descent. The 1856 patent is for a vapor compression system using ether, alcohol or ammonia. He built a mechanical ice machine in 1851 on the banks of the Barwon River at Rocky Point in Geelong, Victoria, and his first commercial ice machine followed in 1854. Harrison also introduced commercial steam compression refrigeration to the factory and meat packing. home, and in 1861, a dozen operating systems.

The first gas absorption cooling system using water-soluble ammonia (called "aqua ammonia") was developed by Ferdinand Carrà ©  © France in 1859 and patented in 1860. Carl von Linde, an engineering professor at Munich University of Technology in Germany, patented an improved liquefaction gas method in 1876. The new process allows the use of gases such as ammonia (NH ₃ ), sulfur dioxide (SO ₂ ) and methyl chloride (CH ₃ Cl) as refrigerant and they were widely used for that purpose until the late 1920s.

Domestic Refrigerator

In 1913, the refrigerator for homes and households was used by Fred W. Wolf of Fort Wayne, Indiana with a model consisting of units mounted on ice boxes. In 1914, engineer Nathaniel B. Wales of Detroit, Michigan, introduced the idea for a practical electric cooling unit, which later became the basis for the Kelvinator. The self-contained refrigerator, with a compressor at the bottom of the cabinet, was created by Alfred Mellowes in 1916. Mellowes produced this refrigerator commercially but purchased by William C. Durant in 1918, which started the Frigidaire company to mass-produce refrigerators.. In 1918, the company Kelvinator introduced the first refrigerator with all kinds of automatic controls. The absorption refrigerator was created by Baltzar von Platen and Carl Munters from Sweden in 1922, when they were still students at the Royal Institute of Technology in Stockholm. It became a worldwide success and was commercialized by Electrolux. Other pioneers include Charles Tellier, David Boyle, and Raoul Pictet. Carl von Linde is the first to patent and create a practical and compact refrigerator.

These housing units usually require the installation of mechanical parts, motors and compressors, in the basement or adjacent space while the cold box is located in the kitchen. There was a 1922 model consisting of a cold box of wood, water cooler, ice cube tray and a 9-cubic-foot (0.25 m) compartment, and cost $ 714. (A 1922 Ford T-Model costs about $ 450.) On 1923, Kelvinator holds 80 percent of the market for electric refrigerators. Also in 1923 Frigidaire introduced the first independent unit. Around the same time as a porcelain-coated vault began to appear. Ice-cube trays were introduced more during the 1920s; Until now, freezing is not an additional function of modern refrigerators.

The first widely used refrigerator was the General Electric "Monitor-Top" refrigerator introduced in 1927, so called because of its similarity to the turret guns on the tight warship USS Monitor in the 1860s. The compressor assembly, which emits a lot of heat, is placed on top of the cabinet, and is flanked by a decorative ring. More than one million units are produced. As a cooling medium, the refrigerator uses sulfur dioxide, which is corrosive to the eye and can cause vision loss, burns and painful skin lesions, or methyl formats, which are highly flammable, harmful to the eyes, and toxic by inhalation or inhalation. digested. Many of these units still function today, after requiring little more service than a replacement start relay or thermostat if at all. This cooling system can not be legally recharged with native refrigerants harmful if leaking or damaged.

The introduction of Freon in the 1920s expanded the refrigerator market during the 1930s and provided a safer and lower-toxicity alternative to previously used refrigerants. Separate freezers became common during the 1940s; the popular term at that time for the unit is deep freeze . This device, or equipment , did not go into mass production for home use until after World War II. The 1950s and 1960s saw technical advances such as automatic ice melting and automatic ice making. More efficient refrigerators were developed in the 1970s and 1980s, although environmental concerns led to the highly effective prohibition of refrigerant (Freon). The early refrigerator model (from 1916) had a cold compartment for ice cube trays. From the late 1920s fresh vegetables were successfully processed through freezing by Postum Company (pioneer of General Food), which had acquired the technology while purchasing rights to Clarence Birdseye's successful fresh freeze method.

The first successful frozen food application took place when the general dietitian Marjorie Merriweather Post (wife of Joseph E. Davies, US Ambassador to the Soviet Union) placed a commercial-grade cleanser at Spaso House, US Embassy in Moscow, before Davies arrival. Post, fear of Soviet food processing security standards, completely store freezers with products from the Birdseye General Foods unit. Frozen food stores allow Davies to entertain with luxury and serve fresh frozen food that is supposed to be out of season. Upon his return from Moscow, the Post (who continued his girl name after divorcing Davies) directed General Foods to market frozen products to upscale restaurants.

Home freezers as separate compartments (larger than necessary for ice cubes only), or as separate units, were introduced in the United States in 1940. Frozen food, formerly luxury goods, became commonplace.

Maps Refrigerator

Freezer

Unit Freezer is used in household and in industry and trade. Foods stored at or below -18 Â ° C (0 Â ° F) are seamlessly secure. Most household freezers maintain temperatures from -23 to -18 Â ° C (-9 to 0 Â ° F), although some freezer units alone can achieve -34 Â ° C (-29 Â ° F) and lower. Refrigerators generally do not reach lower than -23 Â ° C (-9 Â ° F), because the same cooling loop serves both compartments: Lowering the temperature of the freezer compartment excessively leads to difficulties in maintaining above-frozen temperatures in the refrigerator compartment. Domestic solidifiers may be included as separate compartments in the refrigerator, or may be separate tools. Domestic soliders are generally upright units resembling fridges or crates (vertical units placed on their backs). Many modern upright freezers come with ice dispensers built into their doors. Some upscale models include thermostat display and controls, and sometimes flat-screen televisions as well.

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Domestic and commercial refrigerators

Commercial refrigerators and freezer units, used by many other names, were used for nearly 40 years before the public house model. They use gas systems such as ammonia (R-717) or sulfur dioxide (R-764), which sometimes leaks, making them unsafe for home use. Household refrigerators were practically introduced in 1915 and gained wider acceptance in the United States in the 1930s because prices were down and non-toxic, non-combustible synthetic refrigerants such as Freon-12 (R-12) were introduced. However, the R-12 damaged the ozone layer, causing the government to issue a ban on its use in new refrigerators and air conditioning systems in 1994. Less harmful replacements for R-12, R-134a (tetrafluoroethane), have been in use since 1990, R-12 is still found in many old systems today.

A common commercial refrigerator is a glass-facing cooler. These types of devices are usually designed for specific re-load conditions which means that they generally have larger cooling systems. This ensures that they are able to cope with large beverages and often open doors. Consequently, it is common for this type of commercial refrigerator to have energy consumption & gt; 4 kWh/day.

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Fridge style

In the early 1950s most refrigerators were white, but from the mid-1950s to present designers and manufacturers colored the fridge. In the late 1950s/early 1960s, pastel colors such as turquoise and pink became popular, brushed chrome-plating (similar to stainless lining) was available on several models from various brands. In the late 1960s and throughout the 1970s, earth tones were very popular, including Harvest Gold, Avocado Green, and almonds. In the 1980s, black became fashionable. In the late 1990s, stainless steel became fashionable, and in 2009, one of the manufacturers introduced a multi-colored design.

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Production by country

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General technical annotations

The vapor compression cycle is used in most household appliances, refrigerator freezers and freezers. In this cycle, circulating refrigerants such as R134a enter the compressor as a low-pressure vapor at or slightly below the refrigerator's interior temperature. Steam is compressed and out of the compressor as a super-pressurized high pressure steam. Super-hot steam runs under pressure through a roll or tube that forms a condenser ; rolls or tubes are cooled passively by air exposure indoors. The condenser cools the melting vapor. When the refrigerant leaves the condenser, it is still under pressure but now only slightly above room temperature. This liquid refrigerant is forced through a metering or throttling device, also known as an expansion valve (basically narrowing the pin hole size in the tubing) to an area with a much lower pressure. A sudden drop in pressure produces a blast-like explosion-like explosion (usually about half) of liquid. The latent heat absorbed by flash evaporation is mostly drawn from adjacent liquid-liquid refrigerants, a phenomenon known as auto-refrigeration . This cold and partially evaporated refrigerant continues through the roll or tube of the evaporator unit. An air-blowing fan from the refrigerator or freezer compartment ("air box") in this coil or tube and the refrigerant completely evaporates, drawing further latent heat from the air box. This refrigerated air is returned to the refrigerator or freezer compartment, and thus keeps the air box cool. Note that the cold air in the refrigerator or freezer is still warmer than the refrigerant in the evaporator. The refrigerant leaves the evaporator, now fully vaporized and slightly heated, and returns to the compressor inlet to continue the cycle.

The modern domestic refrigerator is highly reliable because motors and compressors are integrated in welded containers, "sealed units", with the most likely to reduce leakage or contamination. For comparison, an external-coupled cooling compressor, such as those in car air conditioners, must have leakage of liquid and lubricant passing through the shaft seal. This causes the requirements for periodic filling and, if ignored, the possibility of compressor damage.

The absorption refrigerator works differently than a refrigerator compressor, using a heat source, such as the combustion of liquefied petroleum gas, solar thermal energy or an electric heating element. This heat source is much quieter than the typical compressor motor in the refrigerator. A fan or pump may be the only mechanically moving part; dependence on convection is considered impractical.

Peltier effect uses electricity to pump heat directly; Fridges that use this system are sometimes used for camping, or in situations where noise is unacceptable. They can be completely silent (if the fan for air circulation is not installed) but less energy efficient than other methods.

Other uses of the absorption refrigerator (or "chiller") include large systems used in office buildings or complexes such as hospitals and universities. This large system is used to cool saline water solutions circulated through the building.

Many of the modern fridges/freezers have a freezer on top and a fridge at the bottom. Most refrigerator-freezers - except for the manual liquefaction model or cheaper unit - use what appears to be two thermostats. Only refrigerator compartments are controlled with the correct temperature. When the refrigerator becomes too warm, the thermostat starts the cooling process and the fan circulates the air around the freezer. During this time, the refrigerator is also getting colder. The freezer control button only controls the amount of air flowing into the refrigerator through the silencer system. Changing the temperature of the refrigerator will inadvertently change the freezer temperature in the opposite direction. Changing the freezer temperature will not affect the temperature of the refrigerator. The freezer controls can also be adjusted to compensate for refrigerator adjustments.

This means the refrigerator can get too warm. However, since only enough air is transferred to the refrigerator compartment, the freezer usually regains the temperature set quickly, unless the door is opened. When a door is opened, either in the fridge or in the freezer, the fan in some units stops immediately to prevent excessive frost on the freezer evaporator coil, since it cools two areas. When the freezer reaches the temperature, the unit will die, no matter what the temperature of the refrigerator. Modern computer cooling devices do not use damper systems. The computer manages the fan speed for both compartments, though the air is still blown out of the freezer.

Some manufacturers offer double compressor models. These models have separate freezer compartments and refrigerators that operate independently of each other, sometimes installed in a single cabinet. Each has separate compressors, condensers and evaporator coils, insulation, thermostats, and doors. Typically, compressors and condenser rolls are mounted on the top of the cabinet, with a single fan to cool both.

This design, in which there is no air passing between the two compartments, provides more precise moisture levels and tighter temperature controls in each compartment. It also requires less energy to operate, because every compressor & amp; the cooling system can be optimized for a certain temperature range. Further, opening the door of one compartment does not affect the temperature of the air or the level of humidity in other compartments. As such, it avoids many of the disadvantages of the more general single-compressor design described above, albeit at higher initial cost and increased system noise. The design manufacturers argue that the increase in costs is compensated over time due to reduced energy use and less food waste due to reduced damage.

The "ultra-cold" or "ultra-low temperature (ULT)" (typically -80 C) freezer, as used to store biological samples, also generally uses two cooling stages, but in cascades. The lower temperature stage uses the same methane, or gas, as a refrigerant, with the condenser stored at about -40 Ã, C in the second stage using a more conventional refrigerant. Famous brands include Forma and Revco (now Thermo Scientific) and Thermoline. For lower temperatures (about -196 Ã, C), laboratories usually buy liquid nitrogen, stored in Dewar gourd, where the sample is suspended.

Alternatives to vapor compression cycles not in current use include:

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Features

New refrigerators may include:

• Automatic disbursement
• A power failure warning that warns the user by flashing the temperature display. This may show the maximum temperature achieved during a power failure, and whether the frozen food has melted ice or may contain harmful bacteria.
• Cold water and ice from a dispenser at the door. The provision of water and ice was available in the 1970s. In some refrigerators, the ice-making process is already inside so users do not have to use ice trays manually. Some refrigerators have a water cooler and a water filtration system.
• A cabinet roller that allows the freezer to scroll for easy cleaning
• Adjustable racks and trays
• A status indicator that tells when it's time to change the water filter
• An ice caddy on the door, which moves the ice maker's storage to the freezer door and saves about 60 liters (2Ã, Â ° C) of usable freezer space. It can also be removed, and helps prevent ice makers from clogging.
• Cooling zone on the refrigerator door shelf. The air from the freezer section is diverted to the refrigerator door, to cool the milk or juice stored on the door shelf.
• A drop down door built in the refrigerator's main door gives easy access to frequently used items such as milk, saving energy because it does not have to open the main door.
• The Fast Freeze function to cool the food quickly using a compressor for a predetermined amount of time and thus lowers the freezer temperature below the normal operating level temporarily. It is recommended to use this feature a few hours before adding more than 1 kg of frozen food to the freezer. For freezers without this feature, lowering the temperature setting to the coldest will have the same effect.

The initial freezer unit collects ice crystals around the clotting unit. This is the result of moisture being inserted into the unit when the door to the freezer is opened condensation on a cold part, then freezes. This ice accumulation requires periodic liquefaction ("liquefaction") of the unit to maintain its efficiency. The Manual Withdrawal Unit (referred to as Cyclic) is still available. Advances in automatic liquefaction eliminated the liquefaction task introduced in the 1950s, but not universally, due to energy performance and cost. These units use counters that simply melt freezer compartments (Freezer Chest) when a number of door openings have been made. The units are just small timers combined with electric heating wires that heat up the freezer wall for a short time to remove all traces of frosting. Also, the starting unit features a freezer compartment located in a larger refrigerator, and is accessed by opening the refrigerator door, and then a smaller internal freezer door; units featuring completely separate freezer compartments were introduced in the early 1960s, becoming the industry standard by the middle of the decade. The older freezer compartment is the main cooling of the refrigerator, and only maintains a temperature of about -6 ° C (21 ° F), which is suitable for storing food for a week.

In the early 1950s, butter patent butter was filed and published by inventor Nave Alfred E. This feature should "provide a new and better food storage container for storing butter or the like that can be quickly and easily removed from the refrigerator. Cabinet for cleaning purposes. "Due to the high interest in this invention, companies in the UK, New Zealand, and Australia began incorporating features into the mass production of refrigerators and soon became a symbol of local culture. However, not long after it is removed from production according to these companies is the only way for them to meet the new ecological regulations and they find it inefficient to have a heat generating device in the refrigerator.

Further progress includes an automated ice unit and a self-contained independent unit.

An increasingly important environmental concern is the disposal of old refrigerators - initially because the freon cooler is damaging the ozone layer - but because old generation refrigerators wear out, the destruction of CFC bearing insulation also causes concern. Modern refrigerators usually use a cooler called HFC-134a (1,1,1,2-Tetrafluoroethane), which does not deplete the ozone layer, not Freon. The A-R 134a is now very unusual in Europe. New refrigerant is used instead. The main refrigerant currently used is R-600a, or isobutane which has a smaller effect in the atmosphere when released. There are reports of refrigerators exploding if the refrigerant isobutane leaking in the presence of a spark. If the coolant leaks into the refrigerator, when the door is not opened (like overnight), the cooling concentration in the air in the refrigerator can build up to form an explosive mixture that can be ignited by the spark from the thermostat or when the light is on when the door is opened, damage and seriously documented injury or even death from the explosion caused.

Disposal of refrigerated refrigerators is regulated, often requiring removal of doors; children playing hide and seek have been breathless while hiding in the discarded fridge, especially older models with latching doors. Since August 2, 1956, under US federal law, refrigerator doors are no longer allowed to be installed so they can not be opened from the inside. Modern units use a magnetic door gasket that holds the door sealed but allows it to be pushed open from the inside. The gasket was discovered, developed and produced by Max Baermann (1903-1984) from Bergisch Gladbach/Germany.

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Type of domestic refrigerator

Refrigerators and domestic freezers for food storage are made in various sizes. Among the smallest is the 4 L Peltier refrigerator that is advertised as being able to accommodate 6 cans of beer. Large domestic refrigerators stand as tall as people and may be about 1 m wide with a capacity of 600 L. Some models for small households fit below the working surface of the kitchen, usually about 86 cm. Refrigerators can be combined with freezers, stacked with a refrigerator or freezer on top, below, or side by side. Refrigerators without frozen food storage compartments may have small sections just to make ice cubes. Freezers may have a drawer for storing food, or they may not have a division (chest freezer).

Refrigerators and freezers may be free standing, or built in the kitchen.

Three different classes of refrigerators are common:

• The compressor refrigerator is the most common type; they make real noise, but are most efficient and provide the greatest cooling effect. Portable compressor compressors for recreational (RV) vehicles and camping use are expensive but effective and reliable. Cooling units for commercial and industrial applications can be made in different sizes, shapes and styles to fit customer needs. Commercial and industrial refrigerators may have compressors located away from the cabinet (similar to split air conditioning systems) to reduce noise interruptions and reduce the load on air conditioning in hot weather.
• The absorption refrigerator can be used in caravans and trailers, and electrified dwellings, such as farms or rural huts, where they have a long history. They may be supported by a heat source: natural gas (propane) or kerosene. Models made for camping and RV usage often have the option to run (inefficiently) on 12 volt battery power.
  • Solar power refrigerators and Thermal mass coolers are designed to reduce electricity consumption. Solar refrigerators have the added advantage that they do not use refrigerants that are harmful to the environment or flammable. A typical solar design is an absorption refrigerator that uses ammonia as a functioning gas, and uses a large mirror to concentrate enough sunlight to reach the temperature required to liberate ammonia gas from the solvent. Most thermal mass refrigerators are designed to use electricity intermittently. Because these units are so isolated, the cooling load is limited mainly to the heat introduced by new items for cooling, and ambient air transfer when the unit is open. Therefore, very little power is required if not often opened.
• The peltier refrigerator is powered by electricity, usually 12 volts DC, but an electric-powered wine cooler is available. Peltier refrigerators are cheap but inefficient and become increasingly inefficient with increasing cooling effects; many of these inefficiencies may be related to temperature differences over short distances between the "hot" and "cold" Peltier cell sides. Peltier refrigerators generally use heat sinks and fans to lower this differential; the only sound produced comes from the fan. Reversing the voltage polarity applied to Peltier cells results in a warming rather than a cooling effect.

Other special cooling mechanisms can be used for cooling, but not yet applied to domestic or commercial refrigerators.

• The magnetic refrigerator is a fridge that works on magnetocaloric effects. The cooling effect is triggered by placing the metal alloy in the magnetic field.
• Acoustic refrigerators are refrigerators that use linear reconstructive reciprocating motors/alternators to produce sounds that are converted to hot and cold using compressed helium gas. The heat is thrown away and cold to the refrigerator.

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Energy efficiency

At home without air conditioning (space heating and/or cooling), refrigerators consume more energy than other home devices. In the early 1990s competitions were held among the major manufacturers to encourage energy efficiency. The current US model that Energy Star qualifies uses 50% less energy than the average model made in 1974. The most energy-efficient unit made in the US consumes about half a kilowatt-hour per day (equivalent to 20 W continuously). But even ordinary units are quite efficient; some smaller units use less than 0.2 kWh per day (equivalent to 8 W continuously). Larger units, especially those with large freezers and icemakers, can use as much as 4 kWÃ, Â · h per day (equivalent to 170 W continuously). The EU uses the mandatory energy-compulsory energy rating label instead of Energy Star; so that the EU refrigerators at the point of sale are labeled according to how energy-efficient they are.

For the US refrigerator, the Consortium on Energy Efficiency (CEE) further differentiates between Energy Star qualified refrigerators. Tier 1 refrigerators are those that are 20% â € <â €

In addition to the standard compressor refrigeration styles used in regular home refrigerators and freezers, there are technologies such as absorption cooling and magnetic cooling. Although this design generally uses a much larger amount of energy than compressor cooling, other qualities such as silent operation or the ability to use gas can support this cooling unit in small cages, mobile environments or in environments where units fail will cause consequential damage.

Many of the refrigerators made in the 1930s and 1940s were much more efficient than most were made later. This is partly due to the addition of new features, such as auto-defrost, which reduces efficiency. In addition, after World War 2, the style of the refrigerator became more important than efficiency. This is especially true in the United States in the 1970s, when the model side by side (known as an American refrigerator outside the US) with ice dispensers and water coolers became popular. However, a decrease in efficiency also partially arises from reducing the amount of insulation to cut costs.

Today

Due to the introduction of new energy efficiency standards, refrigerators made today are much more efficient than those made in the 1930s; they consume the same amount of energy while three times larger.

The efficiency of the old refrigerator can be increased by melting the ice (if the unit is manual melting) and cleaning it regularly, replacing old and worn door seals with new ones, adjusting the thermostat to accommodate the actual contents (the refrigerator does not need to be colder than 4 Ã , Â ° C (39Ã, Â ° F) to store drinks and non-perishables) and also replace the insulation, if any. Some sites suggest that you clean the condenser rolls every month or so on units with rolls on the back. It has been proven that this is very little to improve efficiency, however, the unit should be able to "breathe" with ample space on the front, rear, side and above the unit. If the refrigerator uses a fan to keep the condenser cool, then it should be cleaned, at least, every year.

The ice-free refrigerator or freezer uses an electric fan to cool the appropriate compartment. This can be called a "forced fan" refrigerator, while a manual defrost unit depends on cold air located at the bottom, versus warm air above to achieve adequate cooling. Air enters through the inlet and passes through the evaporator where it is cooled, air is then circulated throughout the cabinet through a series of channels and vents. Since the air passing through the evaporator should be warm and humid, the frost begins to form in the evaporator (especially in the freezer evaporator). In cheaper and/or older models, the ice melting cycle is controlled through a mechanical timer. The timer is set to turn off the compressor and fan and energize the heating element located near or around the evaporator for about 15 to 30 minutes every 6 to 12 hours. It melts the ice or ice that accumulates and allows the refrigerator to work normally again. It is believed that ice-free units have a lower tolerance for frost, because their coolers are like evaporator coils. Therefore, if the door is left unintentionally open (especially freezers), the ice melting system may not remove all ice, in this case, the freezer (or refrigerator) should be liquefied.

If the ice melting system melts all the ice before the melting period of the ice is over, then a small appliance (called a frost barrier) acts like a thermostat and closes the heating element to prevent overly large temperature fluctuations, also prevents the explosion of hot air when the system starts again, early defrosting. In some early frost-free models, the defrost limiter also sends a signal to the ice-melt timer to start the compressor and fan as soon as it covers the heating element before the time defrost cycle ends. When the disbursement cycle is complete, the compressor and fan are left to rotate again.

Ice-free refrigerators, including an early freezer/freezer freezer that uses cold plates in their fridge instead of airflow from the freezer section, generally do not turn off their refrigerator fans during the ice flower liquefaction. This allows consumers to leave food in the main refrigerator compartment found, and also helps keep vegetables moist. This method also helps to reduce energy consumption, because the refrigerator is above freezing and can pass the warmer air from freezing through evaporator or cold plate to assist the disbursement cycle.

Regarding the total cost of the life cycle, many governments offer incentives to encourage recycling of old refrigerators. One example is the Phoenix refrigerator program launched in Australia. This government incentive took an old refrigerator, paid the owner to "donate" the refrigerator. Refrigerators are then refurbished, with new door seals, thorough cleaning and removal of items, such as a cover tied to the back of many older units. The resulting refrigerator, now more than 10% more efficient, is then distributed to low-income families.

With the advent of digital inverter compressors, energy consumption is even lower than that of single speed induction motor compressors, and thus contributes much less in greenhouse gas paths.

Lifestyle effects

Refrigerators allow modern families to keep fresh food for longer than ever. The most important improvement is for meat and other highly perishable items, which need to be refined to get anything that resembles shelf life. (On the other hand, refrigerators and freezers can also be filled with processed, unhealthy fast cooking.) The transit cooling allows to enjoy food from distant places.

Dairy products, meat, fish, poultry and vegetables can be stored in the refrigerator in the same room in the kitchen (although raw meat should be kept separate from other foods for hygiene reasons).

Freezers allow people to buy large amounts of food and eat it in their spare time, and large purchases save money. Ice cream, a popular commodity of the 20th century, was previously only available by traveling to where the product was made and eating it in place. Now this is a common food. Ice on demand not only adds to the enjoyment of cold drinks, but is useful for first aid, and for cold packs that can be kept frozen for picnics or in an emergency.

Temperature zone and ratings

Some refrigerators are now divided into four zones to store different types of food:

• -18Ã, Â ° C (0Ã, Â ° F) (freezer)
• 0 Â ° C (32Ã, Â ° F) (meat zone)
• 5Ã, Â ° C (41Ã, Â ° F) (cooling zone)
• 10Ã, Â ° C (50Ã, Â ° F) (sharper)

Refrigerator capacity is measured in liters or cubic feet. Usually the combined refrigerator-freezer volume is divided by 1/3rds to 1/4 of volume allocated to the freezer although these values ​​vary greatly.

Temperature settings for refrigerator and freezer compartments are often given random numbers by manufacturers (eg, 1 to 9, warmest to coldest), but generally 3 to 5 Â ° C (37 to 41 Â ° F) is ideal for refrigerator compartments and -18 Â ° C (0 Â ° F) for the freezer. Some refrigerators must be within certain external temperature parameters to run properly. This can be a problem when placing the unit in an unfinished area, such as a garage. European freezers, and refrigerators with freezer compartments, have a four star rating system for class cleaners.

• [*] Ã,: min temperature = -6Ã, Â ° C (21Ã, Â ° F). The maximum storage time for food (pre-freeze) is 1 week
• [**] Ã,: min temperature = -12Ã, Â ° C (10Ã, Â ° F). The maximum storage time for food (pre-freeze) is 1 month
• [***] Ã,: min temperature = -18Ã, Â ° C (0Ã, Â ° F). The maximum storage time for food (pre-freeze) is between 3 and 12 months depending on the type (meat, vegetables, fish, etc.)
• [ * ***] Ã,: min temperature = -18Ã, Â ° C (0 Â ° F). The maximum storage time for pre-frozen or frozen-from-fresh food is between 3 and 12 months

Although three and four star ratings determine the same storage time and the same minimum temperature of -18 Â ° C (0 Â ° F), only four-star freezers are intended to freeze fresh food, and may include a "quick freezing" function (running the compressor continuously, to as low as -26 ° C (-15 ° F)) to facilitate this. Three (or fewer) stars are used for frozen food compartments suitable only for storing frozen food; Incorporating fresh food into such compartments is likely to produce an unacceptable temperature rise. This categorization difference is shown in the design of the 4-star logo, where a three-star "standard" is displayed in the box using a "positive" color, which shows the same normal operation as a 3-star freezer, and a fourth star indicates additional fast frozen/prefixed to the box in "negative" color or with other different formats.

Most European refrigerators include cold, humid refrigerator parts (which do require automatic liquefaction) at irregular intervals and freezer sections (which are rarely frozen).

Commercial cooling temperature

(from the warmest to the coolest)

• Refrigerator 35Ã, Â ° F to 38Ã, Â ° F, and no larger than the maximum refrigerator temperature at 41Ã, Â ° F
• Freezer, Reach-in -10Ã, Â ° F to 5Ã, Â ° F
• Freezer, Walk-in -10Ã, Â ° F to 0Ã, Â ° F
• Freezer, Ice Cream -20Ã, Â ° F to -10Ã, Â ° F

See also

References

Further reading

• Rees, Jonathan. Refrigeration Nation: History of Ice, Tools, and Companies in America (Johns Hopkins University Press; 2013) 256 pages

External links

• AS. Patent 1,126,605 Refrigeration Equipment
• AS. Patent 1,222,170 Refrigeration Equipment
• History of Refrigerators and Refrigerators
• How the Fridge Works Articles by HowStuffWorks
• Refrigerator, Canada Science and Technology Museum
• The way modern household refrigerators are made (video)

Source of the article : Wikipedia