Refrigerator
The volume of a household refrigerator is typically 20 to 500 liters. In 1910, the world's first compression-type refrigerator for domestic use appeared in the United States. In 1925 the Swedish company Lido developed a domestic absorption refrigerator. In 1927 General Electric of the United States developed a fully enclosed refrigerator. In 1930, air-cooled continuous diffusion absorption refrigerators with different heating methods were put on the market. In 1931, a new refrigerant Freon was successfully developed. 12. Domestic thermoelectric refrigerators began to be produced in the late 1950s and China started production of refrigerators in the 1950s.
Historical origin
Human beings already know that keeping food at low temperature reduces the risk of spoilage. In the Shang Dynasty (17th century BCE to 11th century BCE), China had learned to use ice to keep food cold. The "Book of the Week" records ancient refrigerators, called Xingjian. "Zhou Li · Tian Guan · Ling Ren" Record: "The beginning of spring is the rule of Xian, where the shame of the outside and the inside is the same, and the wine of the wine is the same. The sacrifices are shared. The snow and the guests by the ice. Shared. "" Works such as a vase with small vase, largemouths of sheng bing, and keeping food in Royal hot air. " 2000 years BC, ancient Babylon in West Asia and tigress ancient inhabitants of the basin have also started using ice frozen meat. In the Middle Ages, original refrigerators that housed pieces of ice in specially made water or stone shelves to preserve food appeared in many countries. By the 1850s, such refrigerators were still available in the United States.
Development Process
"Vueau Spring and Autumn" also recorded: "Gojian also travels, relaxes and eats at Ice Cook." The "ice cooks" described here are used to store ancient peopleAncient refrigerator
Ancient refrigerator
A house that holds food is a place where food is served in summer. [1-2]
In the Tang dynasty, people learned to make artificial ice, and the method of obtaining ice is no longer limited to the weather. The pattern of ice products has gradually increased. There are businessmen specializing in ice products on the market. They also added sugar to the ice. attract customers. During the production of gunpowder, people produced a lot of saltpeter and found that the saltpeter absorbed a lot of heat when dissolved in water, which could cause the water to cool to freeze, and people could make ice in summer.
In the Song Dynasty, apart from drinking cold wine, you can also eat a variety of cold drinks. Cold drinks are more diverse in the market, and there are more cold drink shops in the night market. Popular cold drinks include "Bingxue Liquorice Soup", "Snow Soybean Water", and "Lishui Lychee Cream". Song Suzanne's "Yuanou Three Years Dragon Boat Festival Posts, Empress Dowager Pavilion" Part Three: "The Water Palace Open the Ice Book, and Jade Pot Frozen Jade Pot." Jian one. It is a sacrifice today, and the heat of summer, please match the sacrificial condition and increase the number of snow. "[3]
During the Ming and Qing dynasties, iced foods were already flooding the streets, and during the midsummer season there were many hawkers selling "cold water" along the road. In folk, it is also popular for eating lotus seed soup in the ferry, which is said to be capable of nourishing the spleen. In the Qing Dynasty, there were specialists who would carry snowflakes from the basement and hide in the cellar in 39 days to meet the demands of royal members and dignitaries for the use of ice when summer arrived.
The term "refrigerator" entered the West only in the American language in the mid-17th century. With the development of the city, snow sales have evolved gradually. It is slowly looking for inns, hotels, hospitals, and some city dealers for meat, fish and preservation. After the Civil War (1861–1865), ice was used in refrigerated trucks, and it also entered civilian use. By 1880, half the refrigerators sold in New York, Philadelphia and Baltimore were already in use in homes. Similar products also have a freezer.
Creating an efficient refrigerator is not as easy as we think. In the early 19th century, the knowledge of the inventors of thermo physics, which was important for refrigeration science, was underdeveloped. In the West, people thought that the best refrigerators should stop the melting of ice, and such a very common view at the time was clearly wrong, as it was the melting of ice that played a cooling role. In the early days, a lot of effort was made to conserve ice, including wrapping it in blankets so that ice would not play its part. It was not until the end of the 19th century that the inventors succeeded in finding the precise balance of insulation and circulation required for the efficient refrigerator.
But in the early 1800s, an inventive Maryland farmer, Thomas Moore, found the right way. He owns a farm about 20 miles from Washington, where Georgetown is the center of the village market. When he used the refrigerator to deliver the butter to the market, he found that customers would quickly pass the melting butter into competitors' buckets and buy them at a price higher than the market price. He was still fresh and stiff, neatly cut into a pound of butter. One of the benefits of its fridge, Mohr said, is that farmers do not need to go to the market at night to keep their products cool.
In 1822, Faraday, a famous British physicist, discovered that carbon dioxide, ammonia, chlorine and other gases would liquefy under pressure, and become a gas when the pressure was lowered. In the process of changing from liquid to gas, a large amount of heat will be absorbed, causing the surrounding temperature to drop rapidly. Faraday's discovery provided a theoretical basis for later inventions of artificial refrigeration technologies such as compressors. The first artificial refrigeration compressor was invented in 1851 by Harrison. Harrison is the owner of Australian "Geelong Advertising". While cleaning the typeface with ether, they found that ether has a strong cooling effect on the metal. Ether is a fluid with a low boiling point and is prone to endothermic evaporation. Harrison researched and produced a freezer using ether and a refrigerator pressure pump, and applied it to a brewery in Victoria, Australia, and to cool during winemaking.
In 1873, German chemist and engineer Karl von Linde invented ammonia as a refrigerant. Linde uses a small steam engine to run the compression system, causing ammonia to be repeatedly compressed and evaporated to produce refrigeration. Linde first applied his invention to the Sedumer brewery in Wiesbaden to design and manufacture an industrial refrigerator. Later, he reformed the industrial refrigerator. Shortened to this, in 1879 the world's first artificially crafted domestic refrigerator was built. This steam-powered refrigerator was quickly put into production, and by 1891, 12,000 units had been sold in Germany and the United States.
The first refrigerator to use a motor to use a compressor was invented in 1923 by Swedish engineers Brighton and Mendes. Later, an American company bought his patent and built the first domestic refrigerator in 1925. In the first refrigerator, the electric compressor and refrigerator were separated. The latter was usually placed in the family floor kiln or storage room, and connected via a pipe to an electric compressor. Prior to the 1930s, most refrigerators used in refrigerators were not safe, such as ether, ammonia, sulfuric acid, etc., or they were flammable, corrosive, or irritant. Later, he starts searching for a safe chill and finds Fron. Freon is a non-toxic, non-corrosive, non-combustible fluorine compound. It soon became a refrigerant for various refrigeration equipment and has been in use for over 50 years. But people also found that Freon has a harmful effect on the ozone layer of the Earth's atmosphere. So people started looking for new and better refrigerants.
Working Principle
According to various classifications of refrigerators, according to the statistical analysis of the "2013-2017 China Refrigerator Industry Market Outlook and Investment Opportunities Analysis Report", there are nine types of working principles:1) Compression type refrigerator: This type of refrigerator is provided with mechanical energy by an electric motor, and the compressor works on the refrigeration system. The refrigeration system is based on the principle of low boiling point refrigerant, which absorbs heat during evaporation and evaporation. Its advantages are long life and easy usage. 91 ~ 95% of refrigerators in the world belong to this category. Common refrigerators use a refrigerant called R600 refrigerant as a hot "porter", "transferring" the hot in the refrigerator to the outside of the refrigerator.
2) Absorption refrigerators: This type of refrigerator can use heat sources (such as gas, kerosene, electricity, etc.) as electricity. The use of ammonia – water – hydrogen mixed solutions achieves the purpose of refrigeration in the continuous absorption – diffusion process. Its disadvantages are low efficiency and slow cooling, which are gradually eliminated.
3) Semiconductor Refrigerator: It is a refrigerator that realizes refrigeration by using the principle of applying direct current on a PN semiconductor to produce a Peltier effect at a node.
4) Chemical refrigerator: It is a refrigerator that uses strong absorption of heat when certain chemical substances are dissolved in water to achieve the cooling effect.
5) Electromagnetic Vibration Refrigerator: It is a refrigerator that uses an electromagnetic vibration machine to run the compressor. Its principle and structure are basically similar to compression refrigerators.
6) Solar Refrigerator: This refrigerator uses solar energy as a refrigerant.
7) Refrigerated adiabatic refrigerator.
8) Radiation refrigeration refrigerator.
9) Solid refrigeration refrigerator.
Types
There are many types of refrigerators that are usually classified according to the type of cooling, use, climate, form and method of cooling.Classification of internal cooling
Forced-circulation air conditioner: also known as an intercooler (air-cooled) refrigerator or without freezing. There is a small fan in the refrigerator to make the airflow in the box, so the temperature in the box is uniform, the cooling rate is high, and the use is convenient. However, due to the defrosting system, energy consumption is slightly higher and manufacturing is relatively complicated.
Natural air convection: also known as a direct refrigerator or freezer. The freezer is directly surrounded by the evaporator, or the evaporator is in the freezer. In addition, an evaporator is provided at the top of the refrigerator compartment. directly absorbs heat for cooling. This type of refrigerator has a relatively simple design and low power consumption, but its temperature inefficiency is slightly worse, which makes its use relatively uncomfortable.
Compulsory circulation of air conditioning and natural convection: mainly new types of refrigerators are used, mainly taking into account the advantages of both refrigerators with wind and direct cooling.
Use classification
Refrigerator: at least one compartment of this type of refrigerator is a refrigerator compartment, which is used to store products that do not need to be frozen, and their temperature must be kept above 0 ° C. However, this type of refrigerator may have a refrigerator compartment, an ice compartment, a compartment for storing frozen foods and a greenhouse for ice, but it does not have a freezer compartment.
Refrigerator with a freezer: this type of refrigerator has at least one compartment as a refrigerator compartment and one compartment as a freezer compartment.
Freezer: At least one refrigerator of this type is a freezer, and can store food in accordance with the rules. There may be a storage room for frozen food.
Climatic and environmental classification
Divided into sub-moderate (SN), moderate (N), subtropical (ST), tropical (T).
Moderate temperature zone (SN), suitable ambient temperature: 10 ℃ ℃ 32 ℃;
Temperate zone (N), suitable ambient temperature: 16 ℃～ 32 ℃;
Subtropical type (ST), ambient temperature suitable use: 18 ℃ ～ 38 ℃;
Tropical type (T), ambient temperature suitable use: 18 ℃ ～ 43 ℃.
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