The operating principle of a refrigerator with one and two compressors, different numbers of chambers and modes. Diagram and principle of operation of different refrigerators

In single-chamber devices, the chamber is cooled from the main evaporator, which is located at the top of the refrigerator. Cooled air from the evaporator flows down and lowers the temperature in the refrigerator compartment. To prevent a sharp drop in temperature, under the main evaporator there is a tray with small holes through which cooled air from the evaporator enters the refrigerating chamber. By opening and closing these holes we can change the temperature in the refrigerator compartment. From the physics course we know that cold air always comes down, and therefore in single-chamber refrigerators the freezer is always on top.

A refrigeration unit in a single-chamber device operates according to the following scheme: the compressor pumps out refrigerant vapors from the evaporator and pumps them into the condenser, where they are cooled, condensed and ultimately enter the liquid phase. Next, this liquid, through a filter drier and capillary tubes, enters the evaporator where it boils and begins to absorb thermal energy from the surface of the evaporator, that is, cooling the contents of the refrigerator. The refrigerant boils off and turns into steam while passing through the evaporator, which is pumped out by the compressor in the same way. The algorithm is repeated cyclically until the temperature on the surface of the evaporator becomes set, after which the thermal relay turns off the compressor.

Under the influence of external climatic influences, the temperature in the freezer increases, and the thermostat reconnects the compressor. Working according to this scheme, a constant temperature is maintained inside the refrigerator. To prevent the formation of condensate, a capillary tube is installed on the surface of the pipeline system along its entire length. During operation, the capillary tube heats up, thereby heating the suction line. In modern models, the capillary tube is located inside the suction pipe.

A two-chamber unit, unlike its single-chamber brother, has two separate evaporators for the refrigerator and freezer compartments, separated by a heat-insulating partition.

The principle of operation of the two-chamber is as follows: the refrigerant pumped by the compressor, through a capillary tube, enters the evaporator of the freezer, where, boiling and evaporating, the cooling process of the surface of the evaporator begins. Until the freezer evaporator freezes to minus values, no refrigerant will flow into the other evaporator located in the refrigeration chamber.

As soon as the evaporator in the freezer freezes, the liquid refrigerant will begin to flow into the evaporator of the refrigerator compartment, lowering its temperature to minus 14 ° C, after which the thermal relay will turn off the compressor. And the compressor will turn on, also automatically, after heating the evaporator to a certain temperature.

The compressor is the heart of any refrigerator or freezer. If there are problems with it, then the refrigerator will definitely not work. The average consumer has a question. Is it possible to test it at home? It turns out that it is not only possible, but also necessary. The main thing is that you have the necessary knowledge and straight hands for this.

The circuit design principle of operation of the thermostat is reviewed and described, as well as options for replacing a burnt-out temperature controller with its simple homemade analogues.

The principles of compressor operation discussed above have one significant drawback - the compressor operates at full power, and even though it is periodically switched off by a thermal relay, the total energy consumption is significantly higher than that of inverter compressors

The operating principle of an inverter-type compressor is as follows: When power is supplied, the refrigerator quickly reaches the set cooling temperature, and then, using a smooth change in compressor power, the required temperature is maintained, while the inverter compressor does not turn off, but only reduces the number of compressor operating cycles per unit time, and the temperature inside The refrigeration chamber is maintained constant.

Troubleshooting is a serious matter, but any radio amateur can make simple repairs with his own hands, and even replace some failed components with alternative amateur radio designs.

Sometimes it happens that when you go to the refrigerator early in the morning, you realize that you forgot to close the door tightly in the evening. The refrigerator defrosted overnight, and it is better to throw some food products in the trash can to prevent poisoning. To avoid this, I suggest assembling a sound alarm, and after some time the device itself will remind you to keep the door open. Of course, some new refrigerator models already have this function built-in, but old, perfectly working budget models need to be upgraded by installing, as an option, this detector circuit.

In many models of modern refrigerators, the doors open on the right side. But from time to time situations arise in which it is necessary to change this principle and move the refrigerator doors to the opposite side.

The lack of lighting in the refrigerator brings a lot of inconvenience, especially in the dark. Old refrigeration devices used standard low-power incandescent lamps; their only drawback was the generation of heat. In modern kitchen appliances, fluorescent and LED lamps are used along with classic incandescent lamps. These types of lamps are much more energy efficient and generate cool white light, and most importantly, they hardly heat up. But even they have to be periodically replaced with new ones, and to do this correctly, you should read this article.

All cooling systems of modern refrigerators can be divided into three classes: static cooling, No Frost system and dynamic cooling. It is these three groups that are the basis of any refrigeration device.

Another name for this system is "Direct Cool". The operating principle is as follows. When the compressor is running, the temperature in the chamber decreases due to heat extraction by the evaporator, which is located in the rear wall of the housing. The temperature of the back wall is low and all the moisture begins to condense and freeze on it. When the temperature drops to a user-specified level, the compressor turns off. After some time, the frozen drops of moisture on the wall begin to melt and flow through a special hole into a container located outside the refrigerator. When the temperature increases to the maximum values ​​​​set by the thermostat settings, the compressor works again and everything repeats in the same sequence. The temperature in the freezer is always in the negative range due to the design features and area of ​​the evaporator.

Defrosting in refrigeration devices with a static cooling system is called manual defrosting. Defrosting refers only to the process of defrosting the freezer chamber, since due to the constant negative temperature, moisture constantly freezes on the walls of the chamber. In the refrigerator compartment, defrosting is carried out automatically.

The disadvantage of such a cooling system is the lack of uniform cooling throughout the entire volume. The cooling intensity in static systems is the lowest. The advantage is maximum preservation of food moisture.

The system can work without defrosting all the time until it breaks down. The principle of its operation is as follows - since the evaporator in such refrigerators is open, the air in the chamber comes into contact with it. No Frost cooling is based on forced air circulation in the refrigerating chamber through the evaporator. While the compressor is operating, the air is driven by a fan through the evaporator, which picks up heat and has a fairly low temperature. All moisture in the air instantly freezes on the evaporator itself. Due to this, frost does not occur. When the compressor turns off when it reaches the set temperature level, the moisture on the evaporator melts on its own and is discharged through a special drainage channel. A similar process occurs in the freezer.

Together with this system, the concept of a multi-flow Air Flow or Multi Air Flow cooling system is used. It cannot be separated into its own cooling system, since this circulation system only increases the cooling efficiency. The advantage of No Frost systems is their excellent cooling efficiency. Since the distributed air flow creates the same temperature in any part of the refrigeration chamber.

Among the disadvantages, products in such refrigerators partially lose their moisture and it is advisable to store them in containers.

In fact, this is an improved static system but with certain improvements, in the form of a chamber fan. The operating principle is the same as in the case of static cooling. A fan provides forced air circulation in the chamber.

This system combines the advantages of the static and No Frost systems, providing the best conditions for storing food.

Modern refrigerator designs use combinations of cooling systems, which is why they cannot be considered as having one specific system. For example, Electrolux produces refrigerators with the Frost Free system. But in the original it is a combination of a static system in the refrigerator and No Frost in the freezer.

A classic refrigerator without a No Frost system works as follows:

The motor-compressor (1) sucks in gaseous freon from the evaporator, compresses it, and pushes it through the filter (6) into the condenser (7).

In the condenser, the freon heated as a result of compression cools to room temperature and finally turns into a liquid state.

Liquid freon, under pressure, enters the internal cavity of the evaporator (5) through the opening of the capillary (8), passes into a gaseous state, as a result of which it removes heat from the walls of the evaporator, and the evaporator, in turn, cools the internal space of the refrigerator.

This process is repeated until the temperature of the evaporator walls set by the thermostat (3) is reached.

When the required temperature is reached, the thermostat opens the electrical circuit and the compressor stops.

After some time, the temperature in the refrigerator (due to exposure external factors) begins to rise, the contacts of the thermostat close, with the help of the protective starting relay (2) the electric motor of the motor-compressor starts and the whole cycle is repeated from the beginning (see point 1)

1-Motor-compressor; 2-Protective starting relay; 3-Thermoregulator; 4-Internal refrigerator lighting lamp; 5-Evaporator; 6-Filter drier; 7-Capacitor; 8-Capillary; 9-Lamp switch

Electrical equipment of refrigerators

The electrical equipment of household refrigerators includes the following devices:
electric heaters: for heating the generator in absorption refrigeration units; to protect the doorway of the low-temperature (freezing) chamber from condensation (fogging) on ​​the walls; for heating the evaporator during semi-automatic and automatic removal of snow cover;
compressor electric motor (this applies to compression refrigerators);
feed-through sealed contacts for connecting the electric motor windings with the external electrical wiring of the refrigerator through the wall of the motor-compressor casing;
lighting equipment designed to illuminate the refrigeration chamber;
fans: for blowing air over the condenser of a refrigeration unit (when using condensers with forced cooling in refrigerators) and for forced air circulation in the refrigerator chambers.

Automation devices for household refrigerators include:
temperature sensors-relays (temperature regulators) to maintain a given temperature in the refrigeration or low-temperature chamber of household refrigerators;
starting relay for automatically turning on the starting winding of the electric motor when starting;
protective relay to protect the motor windings from overload currents;
automatic devices for removing snow cover from the evaporator walls

Electrical circuit of the refrigerator and the principle of its operation.
When voltage is applied, electric current passes through the closed contacts of the thermostat (3), the defrost button (10), the thermal protection relay (11), the starting relay coil (starting relay contacts 12.2 are still open) and the working winding of the motor-compressor electric motor.
Since the engine is not yet rotating, the current flowing through the working winding of the motor-compressor is several times higher than the rated one, the starting relay (12) is designed in such a way that when the rated current value is exceeded, the contacts (12.2) are closed, and the starting winding of the electric motor is connected to the circuit. The engine begins to rotate, the current in the working winding decreases, the starting relay contacts open and the engine continues to operate in normal mode.
When the walls of the evaporator cool down to the value set on the thermostat, the contacts (3) open and the electric motor of the motor-compressor stops.
Over time, the temperature inside the refrigerator rises, the thermostat contacts close and the whole cycle repeats.
The protection relay is designed to turn off the engine when the current increases dangerously. On the one hand, it protects the engine from overheating and breakdown, and on the other, your apartment from fire.
The relay consists of a bimetallic plate (11.1), which, when the temperature rises, bends and opens the contacts (11.2); after the bimetallic plate cools, the contacts close again.

What materials is the refrigerator made of?

To put it simply, a refrigerator consists of an isothermal cabinet and electrical equipment (refrigeration unit)

Frame
The body is a supporting structure, so it must be quite rigid. It is made of sheet steel with a thickness of 0.6-0.1 mm. The tightness of the outer cabinet is ensured by PV-3 paste based on vinyl chloride resin. The surface of the cabinet is phosphated, then primed and coated twice with white enamel ML-12-01, EP-148, ML-242, ML-283 or others. This is done using spray guns or in an electrostatic field. The surface of the serving table, if any, is coated with polyester varnish.

Recently, impact-resistant plastics are increasingly being used to make refrigerator bodies. This reduces metal consumption and reduces the weight of the refrigeration appliance.

Refrigerator interior cabinets
Metal internal cabinets made of steel sheet with a thickness of 0.7-0.9 mm are made by stamping and welding and hot-enameled with titanium silicate enamel.

Plastic chambers are made from ABS plastic or impact-resistant polystyrene using vacuum forming. ABS (acrylic butadiene styrene) has high mechanical properties and resistance to freon. ABS plastic parts coated with chrome and nickel are widely used for decorative purposes. Domestic ABS plastics are divided into four groups according to their physical and mechanical properties:
ABS-0903 medium impact strength;
ABS-1106E, ABS-1308, ABS-1530, ABS-2020 with increased impact strength;
ABS-2501K, ABS-2512E, ABS-2802E with high impact strength;
ABS-0809T, ABS-0804T, ABS-1002T with increased heat resistance.
ABS plastics are produced in the form of granules with a diameter of no more than 3 mm and a length of 4-5 mm or in powder form and are processed by injection molding, blowing, and thermoforming. The chambers of freezers and the chambers of low-temperature compartments of refrigerators are metal - made of aluminum or stainless steel. Steel chambers are more durable and hygienic, but they increase the weight of the refrigerator and require special methods of attachment to the outer casing for the most effective thermal insulation from the environment.
The advantages of plastic chambers include manufacturability, low thermal conductivity, and lower weight. However, such cameras age faster, lose their presentation over time, are less durable and less durable compared to metal ones. In refrigerators with plastic chambers, linings covering the thermal insulation are not installed around the perimeter of the doorway, since the role of linings is played by the flanged edges of the chamber.

Doors
Manufactured from steel sheet 0.8 mm thick by stamping and welding. Some refrigerator models have doors made of particleboard or impact-resistant polystyrene.

The refrigerator door consists of outer and inner panels, thermal insulation between them and a seal. Door panels are made from impact-resistant polystyrene using vacuum molding. Sheet thickness 2-3 mm. Most refrigerator doors open from left to right. All modern refrigerators provide for door re-hanging, i.e. Possibility of opening the door from right to left. Wall-mounted refrigerators have double-leaf doors.

The refrigerator door must fit snugly against the doorway, otherwise warm air will enter the chamber. To ensure tightness, the inside of the door is edged around the entire perimeter with a magnetic seal of different profiles. Older refrigerator designs used balloon-type rubber seals.

Doors are held in the closed position using mechanical (usually trigger-type) or magnetic closures. The latter are the most common. If they are available, the door handle can be positioned at different heights, based on the requirements of technical aesthetics. Replacing door hinges with special hinges, fixed at the top and bottom of the door, reduces the overall dimensions of the refrigerator when the door is opened, which is important when installing refrigerators in the corner of rooms.

Thermal insulation
Thermal insulation is used to protect the refrigerator compartment from the penetration of environmental heat and is laid along the walls, top and bottom of the refrigerator and refrigerator compartment, as well as under the inner door panel. Thermal insulation materials are required to have a low thermal conductivity coefficient, low volumetric mass, low hygroscopicity, moisture resistance, be fire-resistant, durable, cheap, bio-resistant, odorless, and also mechanically strong. For thermal insulation of cabinets and refrigerator doors, staple fiberglass MT-35, MTX-5, MTX-8, mineral felt, polystyrene foam PSV and PSV-S and polyurethane foam PPU-309M are used.

Mineral felt is made from mineral wool by treating it with solutions of synthetic resins. The starting materials for producing mineral wool are mineral rocks (dolomite, dolomite-clay marl), as well as metallurgical slag.

Glass felt is a type of artificial mineral felt. It consists of thin (thickness 10-12 microns) short glass threads bound with synthetic resins. Thermal insulation made of glass felt and superfine fiber is bio-resistant, odorless, water-repellent, easy to install and therefore often used.

Expanded polystyrene is a synthetic thermal insulation material. It is a lightweight, solid, porous gas-filled plastic with evenly distributed closed pores. Thermal insulation from expanded polystyrene is obtained by foaming liquid polystyrene directly into the walls of the refrigerating chamber and the body of the refrigerator cabinet.

Polyurethane foam - foam plastics with a fine-pored rigid structure, obtained by expanding polyurethane resins using appropriate catalysts and emulsifiers. To increase the heat-shielding properties, freon-11 and others are used as an intumescent gas. The process of foaming and hardening of the foam occurs within 10-15 minutes at temperatures up to 5 °C.
Polyurethane foam has a low volumetric mass, low thermal conductivity, and is moisture resistant. It can be foamed directly in the refrigerator. At the same time, it fills the entire space in the walls evenly and without air cavities, adheres well to the walls, increasing the strength of the cabinet.

Depending on the quality of the thermal insulation materials, the thickness of the insulation in the walls of the refrigerator cabinet can be from 30 to 70 mm, in the door - from 35 to 50 mm. Replacing fiberglass thermal insulation with polyurethane foam insulation allows, with the same body dimensions, to increase the volume of the refrigerator by 25%.

Door locks and seals
Previously, refrigerators used trigger and sector door shutters. Modern refrigerators use magnetic closures.

Magnetic closures are an elastic magnetic insert placed in a sealing profile on the inner panel of the door. When the door is closed, it is tightly drawn to the metal body. The starting raw material for the production of magnetic materials is barium ferrite BaO mixed with rubbers or polyvinyl and other resins that give it flexibility. The produced elastic magnet strips are magnetized in a magnetic field.

By attracting the seal to the cabinet along the entire perimeter, the magnetic shutter provides a good seal and at the same time does not require force to open the door, which must be checked with a dynamometer with an error of +1 N. The dynamometer is attached to the handle at the distance furthest from the hinges. The force should be directed perpendicular to the plane of the door.

For door seals in refrigerators with trigger and sector shutters, food-grade rubber is used; with magnetic shutters, polyvinyl chloride and polyvinyl chloride seals with a magnetic insert and magnetic seals with additional holders are used. In refrigerators with a mechanical shutter, tight closing of the door is achieved by compressing the profile of the rubber seal.

In refrigerators with a magnetic shutter, the seal is attracted to the cabinet by the force of attraction of the magnet, and the profile of the seal is stretched. The compactor has two cylinders. The rectangular cylinder, in which the magnetic insert is located, is pressed against the cabinet by its front plane. The thickness of the cylinder wall significantly affects the force of attraction of the seal and does not exceed 0.45 mm. The accordion cylinder serves to compensate for the small free movement of the door. In the free state of the seal, the “accordion” is somewhat compressed and, when the door moves away, it stretches, preventing the seal from coming off from the cabinet. For efficient operation, the “accordion” cylinder profile has low tensile strength, which is ensured by the thin walls of the cylinder, as well as its appropriate configuration.

The magnetic inserts of the seal units are made of rectangular cross-section. They are made from elastic multicomponent ferrite-filled compositions. It has become possible to improve the magnetic, physicochemical and thermomechanical properties, as well as the technical and economic indicators of magnetic elastic inserts thanks to the use of new polymer compositions based on EVA copolymers.

The door seal should be checked without plugging in the refrigerator. A paper strip 50 mm wide and 0.08 mm thick, placed between the door seal and the closed surface of the cabinet, should not move freely in any place.

It is difficult to imagine a modern apartment without a refrigerator. Everyone knows that a refrigerator retains cold inside itself, so food stored in it does not spoil for a long time. How does a refrigerator work?

The refrigerator has 4 main components:

1. Refrigerant- a substance that circulates and transfers heat. Freon gas is used as a refrigerant.

2. Compressor- a motor that operates on the principle of a pump and drives the refrigerant in a circle.

3. Capacitor- through it the heat goes out into the environment. The condenser is a grill on the back wall of the refrigerator.

4. Evaporator- it takes heat from the refrigerator. Typically the evaporator is the inner wall of the refrigerator.

The compressor draws refrigerant from the evaporator. The refrigerant is in a vapor state at this moment. The compressor pumps it under pressure into the condenser. The refrigerant is compressed under pressure, that is, it changes from a gaseous state to a liquid. At the same time, its temperature rises. Hot gas, passing through the condenser pipes, gives off heat to the surrounding space and, as a result, cools to room temperature.

The refrigerant then enters the evaporator through a very narrow opening (capillary). Its pressure decreases sharply, and due to this, the refrigerant evaporates - it boils, turning into steam. At the same time, it cools down greatly. As a result, it removes heat from the walls of the evaporator, and the evaporator, in turn, cools the interior of the refrigerator and the food contained in it.

Thus, the refrigerant works in a cycle: in the condenser, under the influence of high pressure, it condenses and turns into a liquid state, highlighting heat, and in the evaporator under the influence of low pressure it boils and turns into a gaseous state, absorbing warm.

The refrigerator must have a thermostat, with which the cooling temperature of the refrigerator compartment is set. When this temperature is reached, the thermostat opens the electrical circuit and the compressor stops.

After some time, the temperature in the refrigerator begins to rise again (under the influence of the environment). Then the contacts of the thermostat close and the electric motor of the motor-compressor starts using a protective starting relay. The entire cycle is repeated from the beginning until the temperature in the refrigerator drops again to the desired value.

That's why we hear the refrigerator start to "rumble" from time to time, and then go quiet again - this is the compressor motor turning on and off.

In the refrigerant circulation diagram in the very first picture, you probably noticed one more link - the filter drier. It is needed to clean and dry the refrigerant that passes through it. The filter drier is a cylinder filled with a substance that absorbs moisture (silica gel or zeolite).

So, the refrigerator is designed in such a way that it doesn't cool air in the chamber, and picks up heat comes out of it and releases it into the environment. This is ensured by the pressure difference in the condenser and evaporator of the refrigerator. The refrigerant moves from a high-pressure area, where it turns into a liquid (condenses), to a low-pressure area, where the refrigerant's pressure decreases and it turns into vapor (evaporates).

The article uses materials from the site secureforms.danfoss.com and

The world's first refrigerator appeared in America in 1805. However, the device was not recognized, and only at the beginning of the twentieth century was the device invented, which was then one of the first to be patented as a refrigerator, and laid the foundation for all refrigeration equipment. To cool an object to a temperature below that which is external, artificial cooling is required with the expenditure of a certain amount of energy. For this method of artificial cooling, special machines were invented that take heat from cooled objects and transfer it outside the treated space. As a result of heat absorption, a cold environment is formed. All refrigerators operate according to this principle.

The structure, composition and principle of operation of a refrigerator is a subject studied a little by physics at school, but not every adult has an idea of ​​how this device works. Analysis and study of the main technical aspects will make it possible in everyday life to extend the service life, as well as to ensure the safe operation of a conventional refrigerated cabinet for the home.

The device of a refrigerator can most easily be considered on the basis of a compression sample device. Indeed, today only such devices are most often used in everyday life.

In general, refrigeration devices are of two types: absorption and compression. Today, as we know, compression models of refrigerators in which the circulation of the refrigerant is forced to start using a motor-compressor are more widely used.

A typical refrigerator consists of the following elements:

• Compressor, a device that pushes refrigerant (special gas) using a piston, creating different pressures in different parts of the system;
• An evaporator, a container that communicates with the compressor, and into which already liquefied gas enters, absorbing heat inside the refrigeration chamber;
• Condenser, a container where compressed gas gives off its heat to the surrounding space;
• Thermostatic valve, a device that maintains the required refrigerant pressure;
• A refrigerant, a mixture of gases (most often it is freon), which, when exposed to the operation of a compressor, circulates a flow in the system, giving and taking away heat at different parts of the cycle.

The most important point in the operation of a compression unit is that it does not produce cold as such, but cools the space by absorbing heat inside the device and transferring it outside. This function is performed by freon. When it enters an evaporator, consisting of aluminum tubes, and sometimes plates welded together, it evaporates and absorbs heat. In older generation refrigerators, the evaporator body is also the freezer body. Therefore, when defrosting this space, you should not use sharp objects to remove ice. If you accidentally damage the evaporator, all the freon will be lost. Without it, the refrigerator will not work and expensive repairs will be required.

How a refrigerator works: how the device works

Under the influence of the compressor, the evaporated freon vapor leaves the evaporator and passes into the condenser space (a system of tubes located inside the walls, as well as on the back of the device). In this condenser, the refrigerant cools relatively quickly and gradually becomes liquid. Moving into the evaporator, the gas mixture is dried in a filter drier and then passes through a capillary tube. Upon entering the evaporator, increasing in the inner diameter of the tube, the pressure drops sharply, and the gas turns into a vapor state. This cycle is repeated until the set temperature is reached inside the device.

Every owner should know how a refrigerator works. This will make it possible to avoid unexpected problems with the device and respond in a timely manner to possible malfunctions in its operation.

Refrigerators with a built-in No Frost system (“no frost”) have only one evaporator. It is hidden in the freezer under a plastic wall. The cold is transferred from it using a fan. That, in turn, is located behind the evaporator. Through the technological openings, a flow of cold air enters the freezer and then into the refrigerator. In order to justify this name, a refrigerator with a “no frost” system is equipped with a defrosting program. This means that several times a day the timer in the device goes off, which activates the heating element under the evaporator. The produced liquid evaporates outside the refrigerator.

To determine cooling capacity, the following “standard” temperature indicators are used:

• The boiling point of the refrigerant in the evaporator should be fifteen degrees Celsius below zero;
• Condensation is achieved at temperatures within minus thirty degrees, respectively, on the Celsius scale;
• The absorption of refrigerant vapor occurs at fifteen degrees Celsius.

The liquid refrigerant in front of the control valve has a temperature of 32 degrees Celsius.

Refrigerator diagram: drawing of the device and working unit

Not a single cooling-producing structure could operate without a properly designed circuit in which all elements and the sequence of their interaction are defined.

The refrigerator circuit is no exception. Only by thoroughly understanding the drawings can you truly understand the operating principle of refrigeration equipment.

In fact, the cooling process does not occur at all as we are accustomed to believe. Refrigerators do not produce cold, but absorb heat, and because of this, the space inside the device is devoid of high temperatures. The refrigerator circuit includes all the elements of the device that are involved in providing cooling of the air inside the device, and the sequence of actions of this mechanism.

From the image in the diagram you can understand the following:

1. Freon enters the evaporation chamber, and passing through it takes heat from the refrigeration space;
2. The refrigerant moves to the compressor, which, in turn, moves it to the condenser;
3. Passing through the above system, the freon in the refrigerator cools down and turns into a liquid substance;
4. The cooled refrigerant enters the evaporator, and while passing into a larger diameter tube, it turns into a gaseous mixture;
5. After this, it absorbs heat from the refrigeration chamber again.

This operating principle is inherent in all compression-type refrigeration units.

Refrigerator condenser: what tasks does it perform?

The refrigerant heats up during operation, just as before it enters the condenser. However, after passing through this condenser, the refrigerant is cooled. Therefore, we can say that a condenser is a pipeline that usually looks like a coil. This is where the refrigerant vapors enter. The coil can be affected by many environmental factors, such as air. In large refrigeration units, water can be used for these purposes.

The refrigerator condenser plays the role of cooling the hot refrigerant vapors. In small refrigerators, this effect is achieved with the help of air; in large refrigerators, water helps it cope with the work.

Almost all refrigerators today, for example, Samsung, Atlant or Indesit, have a competent composition of components. They have built-in reliable capacitors. However, even they can fail if used incorrectly. Only specialists can fix this problem.

Types of capacitors in refrigerators:

• Side. This type of capacitor is mounted on the side of the device and has a number of advantages and disadvantages.
• The capacitor may be located at the bottom of the device. This type of device works faster, but gets clogged very quickly.
• Models with plate fins. They are air cooled.

Regardless of the type of capacitor your model has, try to keep it in order to prevent damage.

An important part of the refrigerator: the evaporator

Continuing to understand how a refrigerator works, let's consider one of its main components - the evaporator, or in simple words - a heat exchanger.

The refrigerator evaporator, which is called the weeping evaporator in modern models, is a very important and fragile part. If through negligence you damage this item, then restoring the operation of the refrigeration unit will not be so easy.

The structure of this device facilitates the transfer of heat from the cooled element to the evaporating element. The fundamental difference between a condenser and an evaporator is that in the first device the refrigerant releases heat to the environment, while the second absorbs it, taking it from the cooled environment.

Evaporators in household refrigerators are:

• Finned tube;
• Sheet-tube.

This important element of the device is made mainly from steel or aluminum. Correct operation of the evaporator is the main key to the success of the entire device.

The principle of operation of the refrigerator (video)

The purpose of a household single-chamber or double-chamber refrigerator and freezer, and maybe a refrigerator-refrigerator, is to provide food products with the temperature necessary for long-term storage. Modern refrigerators are equipped with a compressor, which is why this type of device is called compression. All components of the unit are very important, so this device must be used with caution.

It is impossible to imagine the home comfort of a modern person without a refrigerator. It is designed for long-term storage of food. According to scientists, each family member opens the door up to 40 times a day. We look inside without even thinking about how our refrigerator works.

In our article we will take a detailed look at the design and operating principle of various refrigerators.

How does a refrigerator work?

Any modern refrigerator consists of the following main units:

1. Engine.
2. Capacitor.
3. Evaporator.
4. Capillary tube.
5. Drying filter.
6. Boiler.

Refrigerator operation diagram

Electric motor

The engine is the main component of a household appliance. Designed to circulate coolant (freon) through the tubes.

The engine consists of two units:

• electric motor;
• compressor.

An electric motor converts electrical current into mechanical energy. The unit consists of two parts - a rotor and a stator.

The stator housing is made of several copper coils. The rotor has the appearance of a steel shaft. The rotor is connected to the engine piston system.

When the motor is connected to the power supply, electromagnetic induction occurs in the coils. It is the cause of torque. Centrifugal force causes the rotor to rotate.

Did you know that the refrigerator accounts for 10% of all electricity consumed. An open appliance door increases electricity consumption several times.

When the engine rotor rotates, the piston moves linearly. The front wall of the piston compresses and discharges the working fluid to working condition.

Refrigerator motor position

In modern refrigeration systems, the electric motor is located inside the compressor. This arrangement blocks the gas from spontaneously leaking.

To reduce vibrations, the engine is mounted on a springy metal suspension. The spring can be located outside or inside the device. In modern units, the spring is located inside the motor housing. This allows you to effectively dampen vibrations during operation of the device.

Capacitor

It is a serpentine pipeline with a diameter of up to 5 millimeters. Designed to remove heat from the working fluid into the environment. The capacitor is located on the rear outer surface of the device.

Evaporator

It is a system of thin tubes. Designed to evaporate the working fluid and cool the surrounding space. Located inside or outside the freezer.

Compressor device

Capillary tube

Designed to reduce gas pressure. It has a diameter of 1.5 to 3 millimeters. Located in the area between the evaporator and condenser.

Filter drier

Designed to purify working gas from moisture. It looks like a copper tube with a diameter of 10 to 20 mm. The ends of the tube are extended and hermetically sealed with the capillary tube and capacitor.

Attention! The filter drier has a one-way operating principle. The device is not designed to operate in reverse mode. If the filter is installed incorrectly, the unit may fail.

Inside the tube there is zeolite - a mineral filler with a highly porous structure. Barrier nets are installed at both ends of the tube.

Filter drier

A metal mesh with cell sizes up to 2 mm is installed on the capacitor side. A synthetic mesh is installed on the side of the capillary tube. The cell sizes of such a grid are tenths of a millimeter.

Boiler

It is a metal container. Installed in the area between the evaporator and the compressor inlet. Designed to bring freon to a boil with subsequent evaporation.

Serves to protect the engine from liquid ingress. Ingress of working fluid can lead to its failure.

How does a refrigerator work?

The main principle of operation of any refrigerator is based on two working operations:

1. Extraction of thermal energy from the device into the surrounding space.
2. Concentration of cold inside the device body.

A refrigerant called freon is used to extract heat. It is a gaseous substance based on ethane, fluorine and chlorine. Freon has the unique ability to pass from a gaseous state to a liquid state and back. The transition from one state to another occurs when pressure changes.

The operation of the cooling system is as follows. The compressor sucks freon inside. An electric motor operates inside the device. The engine drives the piston. When the piston moves, the gas is compressed.

Schematic diagram of the refrigerator

The gas compression process is divided into two stages. At the first stage, the piston returns. When the piston moves, the intake valve opens. Through the open hole, freon enters the gas chamber.

In the second stage, the piston moves in the opposite direction. During the reverse movement, the piston compresses the gas. The compressed freon presses on the outlet valve plate. The pressure in the chamber rises sharply. As the pressure increases, the gas heats up to a temperature of 100° C. The exhaust valve opens and releases the gas to the outside.

The heated freon from the chamber enters the external heat exchanger (condenser). Along the way through the condenser, freon gives off heat to the outside. At the end point of the condenser, the gas temperature decreases to 55° C.

Did you know that the very first refrigerators used sulfur dioxide as a refrigerant? Such devices were very dangerous due to the high probability of system depressurization.

During the heat transfer process, gas condensation occurs. Freon turns from a gaseous state into a liquid.

From the condenser, liquid freon enters the filter drier. Here moisture is absorbed by a special sorbent. From the filter, freon gas enters the capillary tube.

The capillary tube plays the role of a kind of plug (obstacle). At the entrance to the tube, the gas pressure decreases. The refrigerant turns into liquid. Freon flows from the capillary tube to the evaporator. When the pressure drops, freon evaporates. Along with the pressure, the temperature of the gas also drops. When the freon enters the evaporator, the freon temperature is – 23° C.

Freon passes through a heat exchanger inside the refrigerator compartment. The cooled gas removes heat from the inner surface of the evaporator tubes. When heat is released, the interior of the refrigerator compartment is cooled.

After the evaporator, freon is sucked into the compressor. The closed cycle repeats.

Main types of cooling systems

Based on the principle of operation, the following types of refrigerators are distinguished:

• compression;
• adsorption;
• thermoelectric;
• steam ejector.

In compression units, the movement of refrigerant is carried out by changing the pressure in the system. The pressure of the working fluid is regulated by the compressor. Compressor refrigeration systems are the most common type of refrigeration device.

In absorption units, the movement of the refrigerant occurs due to its heating from the heating system. Ammonia is used as the working mixture. The disadvantage of the system is the high danger and complexity of maintenance. This type of household appliance is obsolete and has now been discontinued.

Did you know that the very first refrigerator was produced by the American company General Electric back in 1911? The device was made of wood. Sulfur dioxide was used as a refrigerant.

The main principle of operation of thermoelectric refrigerators is based on the absorption of heat during the interaction of two conductors during the passage of electric current through them. This principle is known as the Peltier Effect. The advantage of the device is its high reliability and durability. The disadvantage is the high cost of semiconductor systems.

Steam ejector units use water. The role of the propulsion system is performed by the ejector. The working fluid enters the evaporator. Here the liquid boils to form water vapor. When heat is generated, the water temperature drops sharply.

Chilled water is used to cool food. Water vapor is removed by an ejector to the condenser. In the condenser, the water vapor is cooled, turns into condensate and again enters the evaporator. The advantage of such installations is their simplicity of design, safety, and environmental friendliness. The disadvantage of the steam ejector system is the significant consumption of water and electricity for heating it.

Working principle of absorption refrigerators

The operation of absorption devices is based on the circulation and evaporation of liquid refrigerant. Ammonia is used as a refrigerant. The role of an absorbent (absorber) is performed by a water-based ammonia solution.

Scheme of operation of the absorption device

Hydrogen and sodium chromate are added to the cooling system of the apparatus. Hydrogen is intended to regulate system pressure. Sodium chromate protects the inner walls of the tubes from corrosion.

Did you know that old Soviet refrigerators use chlorine-based R12 freon as a cooling mixture. The main disadvantage is its destructive effect on the Earth's ozone layer.

When connected to the power supply, the generator-boiler heats up the working fluid. The working mixture is an aqueous solution of ammonia. The ammonia solution is in a special tank.

Heating the refrigerant causes ammonia to evaporate. Ammonia vapor enters the condenser. Here the ammonia condenses and turns into a liquid.

Liquefied ammonia enters the evaporator. From here, liquid ammonia is mixed with hydrogen. The pressure difference between the two substances causes ammonia to evaporate. The evaporation process is accompanied by the release of heat and cooling of ammonia to -4° C. Together with ammonia, the evaporator is cooled.

The cooled evaporator absorbs heat from the surrounding area. After evaporation, the ammonia enters the adsorber. The adsorber contains clean water. Here the ammonia is mixed with water. The ammonia solution enters the tank. The ammonia solution from the reservoir enters the generator-boiler and the closed cycle is repeated.

Aqueous solutions of acetone, lithium bromide, and acetylene can be used as a substitute for ammonia.

The advantage of absorption devices is the quiet operation of the units.

Operating principle of a self-defrosting refrigerator

The defrosting process in units with a self-defrosting system occurs automatically.

There are two types of self-defrosting systems:

1. Drip.
2. Windy (No frost).

In devices with a drip system, the evaporator is located on the rear wall of the device. During operation of the device, frost forms on the back wall. When defrosting, frost flows through special gutters into the lower part of the device. The compressor, heated to a high temperature, evaporates the liquid.

In installations with a wind system, cold air from the evaporator on the rear wall is blown into the housing by a special fan. During the defrosting cycle, frost flows down the grooves into a special hole.

Industrial refrigerators

Industrial devices differ from household devices in the installation power and the size of the cooling chambers. The engine power of the equipment reaches several tens of kilowatts. The operating temperature of freezers ranges from + 5 to – 50° C.

Did you know that the largest industrial refrigerator occupies 24 km2 of area. This giant is located in Geneva (Switzerland) and serves for scientific purposes during the operation of the hadron collider.

Industrial units are designed for cooling and deep freezing large quantities of food. The volume of freezers ranges from 5 to 5000 tons. Used in procurement and processing enterprises.

Operating principle of an inverter refrigerator

Inverter compressors are designed to accumulate and convert direct current into alternating current with a voltage of 220 V. The operating principle is based on the ability to smoothly control the engine shaft speed.

Inverter motor device

When turned on, the inverter quickly picks up the required number of revolutions to create the required temperature inside the case. When the specified parameters are reached, the device goes into standby mode. As soon as the temperature inside the housing rises, the temperature sensor is triggered and the engine speed increases.

Refrigerator thermostat device

The thermostat is designed to maintain a set temperature inside the system. The device is hermetically sealed at one end of the capillary tube. The other end of the capillary tube is connected to the evaporator.

The main element of the thermostat device of any refrigerator is the thermostat. The design of the thermal relay consists of a bellows and a power lever.

Thermostat device

A bellows is a corrugated spring containing freon in its rings. Depending on the temperature of the freon, the spring is compressed or stretched. As the refrigerant temperature decreases, the spring contracts.

Did you know that modern household refrigerators use R600a freon based on isobutane. This refrigerant does not destroy the ozone layer of the planet and does not cause a greenhouse effect.

Under the influence of compression, the lever closes the contacts and connects the compressor to operation. As the temperature rises, the spring stretches. The power lever opens the circuit and the motor turns off.

Refrigerator without electricity - fact or fiction?

Nigerian resident Mohammed Ba Abba received a patent for a refrigerator without electricity in 2003. The device consists of clay pots of different sizes. The vessels are stacked into each other according to the Russian “matryoshka” principle.

Refrigerator without electricity

The space between the pots is filled with wet sand. A damp cloth is used as a cover. Under the influence of hot air, moisture from the sand evaporates. The evaporation of water leads to a decrease in the temperature inside the vessels. This allows long time store food in hot climates without using electricity.

Knowledge of the structure and operating principle of the refrigerator will allow you to perform simple repairs of the device yourself. If the system is configured correctly, then the device will work for many years. For more complex malfunctions, you should contact service center specialists.