How does a refrigerator circuit work?

The working principle of the refrigerator: the mechanical energy is provided by the electric motor, and the work of the cooling system is carried out by the compressor.

In the refrigeration system, it is mainly composed of four parts: compressor, condenser, evaporator and capillary restrictor, which is a closed circulation system. The evaporator is installed above the inside of the refrigerator, and the other parts are installed on the back of the refrigerator. The system is filled with a substance called "CF2Cl2" (international symbol R12) as a refrigerant.

R12 is vaporized into gas by low-pressure liquid in the evaporator, which absorbs the heat in the refrigerator and lowers the temperature in the box.

The gaseous R12 is sucked in by the compressor, which is compressed into a high-temperature and high-pressure gas by the work of the compressor, and then discharged into the condenser. In the condenser, the R12 continuously releases heat into the surrounding space, gradually condensing into a liquid. These high-pressure liquids must flow through the capillaries and throttle and depressurize before they can slowly flow into the evaporator, where they continue to vaporize and endothermy.

In this way, the refrigerator uses electrical energy to do work, and with the help of the refrigerant R12, the heat around the evaporator in the box is transferred to the condenser behind the box to be released, and so on and so on, so as to achieve the purpose of refrigeration.

How to choose a refrigerator

1. The capacity of the refrigerator. In general, it is recommended to choose more than 200 liters for household refrigerators, which can effectively collapse the world to avoid unsatisfactory preservation effects due to too much food, and if the group is less than 2 people, you can consider choosing a capacity of about 200 liters to avoid excessive waste.

2. Refrigeration mode. The most common cooling methods on the market are direct cooling, air cooling, and hybrid cooling. In general, air-cooled frost-free refrigerators are more accurate in refrigeration than direct-cooled refrigerators.

Mixed cold refrigerators complement each other's strengths, with refrigeration and water replenishment and frost-free freezing. However, the cost is high and the space utilization rate is low.

3. Circulatory system. The function of recirculating refrigeration is to prevent food odors. It is divided into single, double and triple cycle refrigeration.

A single-cycle system means that there is only one evaporator for refrigeration, and if it is a refrigerator with a frozen area and a refrigerated area, the temperature can only be adjusted together. If the dual-circulation system and the triple-circulation system have two or three evaporators, it will be better to adjust the temperature in different areas to prevent the food from producing odors.

4. a compressor. It is an important accessory of the refrigerator, which controls the speed of the compressor to adjust the refrigeration temperature. Refrigeration compressors are divided into fixed-frequency and inverter-frequency compressors. Generally, inverter compressors are used, which can ensure that the compressor runs at a balanced speed and saves more than 30% of energy.

The working principle of the refrigerator is divided into 4 processes:

1. Compression process:

Plug in the power cord of the refrigerator, when the contact of the thermostat is turned on, the compressor starts to work, and the low-temperature and low-pressure refrigerant is sucked in by the compressor, and is compressed into high-temperature and high-pressure superheated gas in the compressor cylinder and discharged into the condenser.

2. Condensation process:

The high-temperature and high-pressure refrigerant gas is dissipated through the condenser, and the temperature continues to drop, and is gradually cooled into saturated vapor at room temperature and high pressure, and further cooled into saturated liquid, and the temperature no longer drops, and the temperature at this time is called condensing temperature. The pressure of the refrigerant is almost constant throughout the condensation process.

3. Throttling process:

The condensed refrigerant-saturated liquid is filtered out of water and impurities by a filter drier and then flows into the capillary, through which the refrigerant is throttled and depressurized, and the refrigerant becomes moist vapor at room temperature and low pressure.

4. Evaporation process:

The heat is then absorbed in the evaporator for vaporization, which not only lowers the temperature in and around the evaporator, but also turns the refrigerant into a cold, low-pressure gas.

The refrigerant coming out of the evaporator is returned to the compressor again, and the above process is repeated, transferring the heat from the refrigerator to the air outside the box, and the purpose of refrigeration is achieved.

The working principle of different refrigerators is also different, and the working principle of various types of refrigerators is as follows:

1. Absorption refrigerator.

This kind of refrigerator is mainly powered by a heat source, and the gas absorption refrigerator often uses ammonia mold and excitation as a refrigerant, so that the evaporation conditions of liquid ammonia can be formed, and it also uses hydrogen as a diffusion agent, using a mixed solution of ammonia, water and hydrogen to complete the refrigeration work.

2. Compression refrigerator.

This type of refrigerator uses an electric motor to provide mechanical energy, which works on the refrigeration system through a compressor. The refrigeration system is made by using the principle of low boiling point refrigerant to absorb heat during evaporation.

3. Semiconductor refrigerator.

The semiconductor refrigerator mainly uses semiconductor materials to produce the Peltier effect when working, and it uses p-type semiconductors and n-type semiconductors to make galvanic couples, which will produce heat release and heat absorption at its nodes after direct energization, so as to achieve the purpose of refrigeration.

4. Chemical refrigerator.

A refrigerator that uses certain chemicals to absorb heat strongly when dissolved in water, resulting in a refrigeration effect.

5. Electromagnetic vibrating refrigerator.

It is a refrigerator that uses an electromagnetic vibrator as the main power to drive the compressor. Its principle and structure are basically the same as those of compression refrigerators.

6. Solar refrigerator.

It is a refrigerator that uses solar energy as a cooling energy source.

Here's how the refrigerator works:

After plugging in the power cord of the refrigerator, the compressor starts to work when the contacts of the thermostat are turned on, and the low-temperature and low-pressure refrigerant is sucked in by the compressor, and is compressed into a high-temperature, high-pressure superheated gas in the compressor cylinder and discharged into the condenser.

The high-temperature and high-pressure refrigerant gas dissipates heat through the condenser, and the temperature continues to drop, and is gradually cooled into saturated steam at room temperature and high pressure, and further cooled into saturated liquid, and the temperature does not drop again, and the temperature at this time is called condensation temperature. The pressure of the refrigerant is almost constant throughout the condensation process.

The condensed refrigerant-saturated liquid is filtered out of water and impurities by a filter drier and then flows into the capillary, through which the refrigerant is throttled and depressurized, and the refrigerant becomes moist vapor at room temperature and low pressure.

Then the evaporator begins to absorb heat for vaporization, which not only reduces the temperature of the evaporator and its surroundings, but also makes the refrigerant become low-temperature, and the refrigerant from the evaporator is returned to the compressor at low pressure, and the above process is constantly repeated, and the heat in the refrigerator is transferred to the air outside the box, and the purpose of refrigeration is realized, which is the working principle of the refrigerator.

Historical origins

Humans have long understood that at lower temperatures, food is not easy to spoil. As early as 2000 BC (20th century BC), the ancient inhabitants of the Euphrates and Tigris rivers in ancient Babylon, Western Asia, began to pile ice cubes in pits to refrigerate meat. During the Shang Dynasty (early 17th century BC to 11th century BC), China also knew how to use ice cubes to refrigerate and preserve food.

In the Middle Ages, primitive refrigerators used to store ice cubes in special water or stone cabinets to preserve food in many countries. Until the 50s of the 19th century, there was still this kind of refrigerator in the United States**. In the West in the mid-17th century, the word "refrigerator" entered the American Chinese language.

With the development of the city, the trading of ice has gradually developed. Gradually, it was used by inns, hotels, hospitals, and some discerning city merchants for the preservation of meat, fish, and butter. After the American Civil War (1861-1865), ice was used in refrigerated trucks, but it also entered civilian use.

By 1880, half of all refrigerators sold in New York, Philadelphia, and Baltimore, and one-third in Boston and Chicago were in household use. There are also freezers in the same category.

Making an efficient refrigerator is not as simple as we think. In the early 19th century, inventors had a shallow understanding of the thermophysics that was essential to the science of refrigeration. In the West, it was believed that the best refrigerator should prevent the melting of ice, but this was a very common belief at the time that was obviously wrong, because it was the melting of ice that played a cooling role.

Early efforts were made to preserve ice, including wrapping it in blankets so that it could not function as it should. It wasn't until the end of the 19th century that inventors succeeded in finding the precise balance of insulation and circulation needed to efficiently refrigerate.