How does the air conditioner (split system). The work of the electrical circuit of the air conditioner Schemes of the split system

The principle of operation of any air conditioner is based on the property of liquids to absorb heat during evaporation and release it during condensation. To understand how this process takes place, consider the air conditioner circuit and its device using the example of a split system:

The main components of any air conditioner are:

• Compressor- compresses freon and keeps it moving along the refrigeration circuit.
• Capacitor— the radiator located in the external block. The name reflects the process that occurs during the operation of the air conditioner - the transition of freon from the gaseous phase to the liquid phase (condensation).
• Evaporator- a radiator located in the indoor unit. In the evaporator, freon passes from the liquid phase to the gaseous (evaporation).
• TRV (thermal expansion valve)- lowers the pressure of freon in front of the evaporator.
• Fans- create a stream of air blowing around the evaporator and condenser. They are used for more intense heat exchange with the surrounding air.

The compressor, condenser, expansion valve and evaporator are connected by copper pipes and form a refrigeration circuit, inside which a mixture of freon and a small amount of compressor oil circulates. During the operation of the air conditioner, the following process occurs:

• Freon gas enters the compressor from the evaporator at a low pressure of 3-5 atmospheres and a temperature of 10-20°C.
• The compressor compresses the freon to a pressure of 15 - 25 atmospheres, as a result of which the freon heats up to 70 - 90 ° C and enters the condenser.
• The condenser is blown with air having a temperature below the freon temperature, as a result, the freon cools down and passes from the gaseous phase to the liquid phase with the release additional heat. In this case, the air passing through the condenser is heated. At the outlet of the condenser, freon is in liquid state, under high pressure, the temperature of freon is 10 - 20 ° C higher than the temperature of atmospheric air.
• From the condenser, warm freon enters the expansion valve (TRV), which in household air conditioners is made in the form of a capillary (a long thin copper tube twisted into a spiral). As a result of passing through the capillary, the freon pressure drops to 3-5 atmospheres and the freon cools down, part of the freon can evaporate.
• After the expansion valve, a mixture of liquid and gaseous freon with low pressure and low temperature enters the evaporator, which is blown room air. In the evaporator, freon completely passes into a gaseous state, taking heat from the air, as a result, the air in the room is cooled. Further, gaseous freon with low pressure enters the compressor inlet and the whole cycle is repeated.

This process underlies the operation of any air conditioner and does not depend on its type, model or manufacturer. In "warm" air conditioners, a four-way valve (not shown in the diagram) is additionally installed in the refrigeration circuit, which allows you to change the direction of freon movement by swapping the evaporator and condenser. In this case, the indoor unit of the air conditioner heats the air and the outdoor unit cools it.

Note that one of the most serious problems during the operation of the air conditioner, it occurs if the freon in the evaporator does not have time to completely go into a gaseous state. Then a liquid enters the compressor inlet, which, unlike a gas, is incompressible. As a result, water hammer occurs and the compressor fails. There may be several reasons why freon may not have time to evaporate. The most common are dirty filters (in this case, the blowing of the evaporator and heat transfer worsens) and the operation of the air conditioner when low temperatures outside air (in this case, supercooled freon enters the evaporator).

1. Fuse 15 amps;
2. Button for turning on the heater fan;
3. Button for turning on the air conditioner;
4. Emergency pressure sensor;
5. Sensor low pressure;
6. The relay of inclusion of an electromagnet of the compressor;
7. Compressor electromagnet;
8. High pressure sensor;
9. Relay for turning on the cooling fan;
10. Cooling Fan;
11. Fuse 20 amp.

You see the simplest electrical circuit of the car air conditioning system, see how it works below:

At the moment the ignition of the car is turned on, 12 volts appears on the fuses "1" and "11", we start the car. Now these fuses have 14 volts.

To start the AK system, turn on button "2" of the interior heater fan. After turning on the fan, 14 volts appears on button "3", press this button and the voltage reaches sensor "4", emergency shutdown of the system. (If in the air conditioning system the pressure will exceed 18 bar, the sensor will open the circuit, and the voltage will not go further, as a result, the air conditioner will turn off, this will prevent the pressure from rising and preserve the integrity of the system.) (Such sensors are not on all AK systems, often they are not available at all.)

If sensor "4" is closed, voltage reaches the low pressure sensor "5", which closes the circuit when the pressure in the AK system exceeds 2 bar. (If the sensor is open, it means that there is not enough pressure in the system to turn it on, or the sensor itself does not work).

If everything is in order, the power comes to the control of the relay "6", after the relay is activated, from the fuse "11" the power is sent to the compressor solenoid "7".

Why do we need a high pressure sensor "8"? In order to avoid trouble from overpressure in the AK system. This sensor should turn on if the pressure in the system is above 15 bar. After turning it on, power is supplied from the fuse "1", is sent to the control of the relay "9". The relay closes the wire that comes from the fuse "11", to additional fan cooling "10".

This is how the simplest electrical circuit works, turning on the car air conditioner system.

There are many types of controls in nature. car air conditioner, climate controls, the system of which includes sensors for interior and outdoor temperatures. There are a lot of circuits for such systems, so I cited only one, the simplest, as an example, to represent how the air conditioning compressor turns on in general and what turns on the cooling fan. On systems with climate control, temperature sensors are installed environment, therefore, if the ambient temperature is below plus five degrees Celsius, the air conditioner will not turn on either. And the air conditioner must be turned on in winter, at least twice a month for 15-20 minutes. To do this, owners of cars with such a control system have to look for a warm place for their car, or heat the ambient temperature sensor with a hairdryer (usually it is installed in front, between the front radiator and bumper).

Mercedes cars have relays that control separate valves that shut off the supply of hot antifreeze to the stove radiator, or mix it in to maintain the temperature in the cabin that YOU set.

On some cars, the climate simply turns off and on the air conditioning compressor, on others, the climate simply opens the dampers and mixes hot air to maintain temperature.

Pressure sensors are also different, for example, on Renault cars there are often sensors with three leads that do not close the wire as shown in the diagram above, but change their resistance depending on the pressure change in the air conditioning system.

On Peugeot cars, the air conditioner radiator cooling fan turns on immediately, along with the compressor, they have two speeds. When the pressure rises to critical, the fan spins faster.

On some models of Mercedes and BMW, there were high-pressure sensors that changed resistance depending on the pressure, and the cooling fan, depending on the resistance of the sensor, gained momentum (the Germans did well, it was interesting to come up with, but these fans are not reliable and the price for them is not small, for example BMW X5 - fan cost $500 in 2008).

The compressors are also switched on in different ways, there is an inclusion with the help of an electromagnet, there is with the help of an electrovalve, which is installed directly inside the compressor (the insides of such compressors are constantly spinning).

ATTENTION!!! If YOU just purchased a car with air conditioning, turn it on, the clutch on the compressor works, the compressor starts to rotate, but there is no cold. Turn off the air conditioner and head to an AK repair specialist. The fact is that our beloved outbidders, who are engaged in the resale of cars, often do not want to spend money on refueling the air conditioning system, and ask electricians to put a jumper on the low pressure sensor "5". If you put it, then the electromagnet on the compressor will work, the compressor will rotate, as a result, it just wedges in. The compressor is not cheap.

My advice to YOU, when buying a new or used car with air conditioning, go to an AK repair specialist.

Why even with a new car? A man bought a new car (DAEWOO Nubira), but since the manufacturer did not add oil to the AK system, the compressor jammed. He had to buy new compressor for 600 USD

In modern premises for a long time with the help of air conditioners the most comfortable climatic conditions are created. In hot weather, the temperature drops to desired value, and in cold weather, a warm microclimate is created in the room. The electrical circuit of the air conditioner is used in various types and models. They are installed on walls, on the floor and under the ceiling. Thanks to modern design, conditioners organically fit into an interior of any room.

Main types of air conditioners

A variety of designs of air conditioning devices allows them to be used in the most different places. For example, mobile air conditioner models do not require installation work. Moves out of the room to the street special block or hose to remove warm air.

Very simple installation and further maintenance of monoblock devices. There are no connectors in the freon lines, so its leakage is completely excluded. Such air conditioners are distinguished by low noise, high efficiency, however, they have a rather high cost.

Mounting window air conditioners carried out in wall openings or windows. During operation, they produce a lot of noise, but due to their low price, ease of installation and maintenance, they are widely popular with consumers.

Split systems are one of the types of air conditioners. Their design includes an outdoor and indoor unit. Both parts are connected using copper pipes. Freon circulates through these pipes. outdoor unit consists of compressor, condenser, fan and throttle. The indoor unit has an evaporator and a fan. There are many modifications of split systems, which allows them to be installed in many places.

General scheme of the air conditioner

Each capacitor contains basic elements that perform certain functions. Inside outdoor unit a condenser is located that converts the gaseous refrigerant into a liquid form. Other important element is a choke or expansion valve. With its help, the pressure of the refrigerant decreases when approaching the evaporator. The evaporator itself is made in the form of a radiator installed in the indoor unit.

During pressure reduction, it is here that the transition of the refrigerant from liquid to gaseous form takes place. The compressor compresses the refrigerant and circulates it around. The fans create the air flows needed to blow around the evaporator and condenser. The connection of all the main elements is carried out using copper tubes. As a result, it forms closed loop through which the refrigerant circulates.

Air conditioner electrical equipment

All the main elements of air conditioning systems cannot work by themselves. All work is provided by the electrical circuit of the air conditioner. General scheme includes several main parts. to the indoor unit is carried out using the terminal block Terminal. There are several terminals in the block itself. N is electrical neutral, #2 supplies power from the control board to the compressor, #3 runs the fan at speed one, and #4 at speed two. Terminal 5 supplies power to the 4-way valve actuator when it enters heating mode.

There are three outputs in the compressor itself: C, R and S, denoting, respectively, the common output of the windings, the working winding and the starting winding of the compressor motor for phase shift. In addition, the circuit includes protection against overloads and overheating, as well as terminals for connecting a fan, capacitor, solenoid valve and other elements.

How air conditioner works

M microprocessor control of the split system is carried out from the microprocessor control panel, which is usually installed in the indoor unit. The microprocessor allows you to perform the following functions:

memorization and playback after turning off and then turning on the system of all parameters set from the control panel;

compressor start delay for 3...6 min after system shutdown;

evaporator temperature control indoor unit in cooling mode. When the evaporator temperature is below -1°C, frost protection is activated;

frost protection delay, which is not activated during the first 5 minutes of compressor operation. Frost protection works as follows - the compressor is turned off and the indoor unit fan runs at a constant speed for 5 minutes, after that, the protection remains on until the set temperature level is reached;

ensuring automatic duration of switching on and parking of the compressor: if the compressor runs continuously for more than 1 hour 45 minutes, the compressor will be stopped for 3 minutes, then turned on and the cycle is repeated; the same happens at a room temperature of 26 ° C for 1 hour 45 minutes and at a fan speed of "low", "medium" for 1 hour 45 minutes; in the dehumidification mode at a temperature above 23 ° C and the thermostat is on, the compressor runs for 8 minutes and stops for 3 minutes, when the thermostat is off, it works for 1 minute and stops for 4 minutes; at a temperature below 23 °C and the thermostat is on, the compressor runs for 2 minutes, followed by a stop for 3 minutes; when the thermostat is off, it works for 1 minute and stops for 4 minutes;

setting the fan speed: in automatic mode the following rotational speeds of the fan of the indoor unit are selected: if the temperature difference between the set and in the room is 2 °С - “high”, if the difference is 1 ... 2 °С - “medium”, if the difference is less than 1 °С - “low”; in heating mode, the rotational speed of the fan of the indoor unit at a room temperature lower than 2 °C is “high”, at a room temperature lower than the set one by 1 ... 2 °C - “medium”, at a temperature 1 °C lower given, it becomes "low"; In heating mode, when the evaporator temperature is below 15°C, the indoor unit fan does not turn on. At temperatures up to 18 °C, the fan operates at a "low" speed. When the evaporator temperature reaches 22°C, the fan starts to run at the set speed; in heating mode, with the thermistor off, the fan speed is set to the “lowest” setting. After turning on the thermostat and reaching a temperature of 22 °C on the evaporator, the rotation speed is set at a given level.

W protection for high pressure in the heating mode, it is carried out according to the indications of the thermistor of the indoor unit. At an indoor unit temperature of 50...52 °C, the outdoor fan is switched off, and at a temperature of 46...48 °C it is switched on.

When the outdoor fan is turned off, the defrost mode of the outdoor unit heat exchanger does not start.

The defrosting of the outdoor unit heat exchanger is controlled by a thermistor installed on the heat exchanger.

Defrosting starts when the following conditions are met: in heating mode, the system has been running for 40 minutes; the temperature of the heat exchanger has reached a value below -3 °C; less than 4 minutes 15 seconds have passed since the high pressure protection was turned off.

Defrosting is terminated when the thermistor temperature reaches 3.1 °C or if the defrosting time has exceeded 10 minutes.

The four-way valve is set to the desired position 5 seconds before the compressor starts.

The indoor fan motor is equipped with a speed sensor. The signal from the sensor goes to the microprocessor. Comparing the current frequency with the preset one, the microprocessor corrects the currents so that the frequency approaches the preset level smoothly. This reduces the noise level when switching from one mode to another. If the speed feedback signal is not received within 12 seconds, the fan motor is considered to be locked. The fan switches off and on again after 3 minutes.

The blind drive is usually equipped with a stepper motor that drives the blinds. The direction of movement, speed and angle of inclination are controlled by the microprocessor depending on the temperature in the room.

Serviceability of the majority domestic air conditioners controlled by light signals (flashing indicator light). If it does not flash when the emergency switch is pressed, the control board needs to be checked. The set of light signals may be different, for their identification it is necessary to use the service manual, but an approximate list of blinking indicator lights due to certain malfunctions may be as follows:

blinks once - the connections of the indoor and outdoor units are faulty;

flashes twice - thermistor room temperature and thermistor of the indoor unit;

flashes three times - the fan motor of the indoor unit;

flashes five times - outdoor unit power circuit;

flashes six times - the thermistor of the outdoor unit;

flashes seven times - outdoor unit control board;

flashes ten times - drainage system.

At the time of buying room air conditioner it is very important to make the right choice specifications and be responsible for the installation. According to statistics, most of the breakdowns of air conditioners occur due to their incorrect and unskilled installation. Correct connection sequence electrical circuit air conditioner is a guarantee of its high-quality and long-term performance. If the air conditioner is still installed incorrectly, then the following negative characteristics may subsequently appear: condensate leakage into the room, freon leakage, etc.

There are two types of installation of air conditioners in the premises: standard and non-standard. Standard installation- the most common, installation of air conditioning near the window, as the compressor is located on the street. It is possible to perform installation in rooms with completed repairs. Such installation is not expensive and does not take much time.
Non-standard installation air conditioner is quite expensive and painstaking work, which is recommended to be done only in the process of repairing the premises, since it involves the chasing of the walls.

Regardless of which installation option you choose, in order to avoid all negative consequences, before starting the installation of the air conditioner and fixtures, it is worth finding out important points. For example, such as the external connection diagram and electrical circuit, the device's power supply system, the location of input devices, transverse section wires and future cable routes, find out the characteristic of the wall used for the wiring route. The electrical circuit of the air conditioner must comply with the rules for the installation of electrical installations and regulatory documents. The participation of a professional team of specialists with the necessary equipment is also important.

Air conditioner connection diagram

The electrical connection diagram of the air conditioner includes the laying of external wiring, fixed every 50 cm with special clamps. The electrical wiring that fits into the boxes is attached to the wall using glue and screws, and concealed wiring located in recesses in the wall corrugated pipes attached with clamps.

When choosing a place to install an air conditioner, first of all, you need to take care of aesthetic characteristics: design and interior. It is recommended to install the air conditioner in the under-ceiling area in a place where a lot of time is not spent, as direct currents of cold air can lead to colds.

Refrigerant circuit diagram

Below is a diagram refrigeration circuit conditioner.

The diagram was taken not from a textbook, but from the manufacturer's service documentation, therefore the designations are given in English.

Compressor- compressor, "the heart of the air conditioner." The compressor compresses the refrigerant and pumps it around the circuit.

heat exchanger- heat exchanger,

• outdoor unit- the external unit, that is, the condenser, cools the compressed freon below the condensation temperature
• indoor unit- indoor unit - evaporator, in it the working substance evaporates, lowering the temperature

expansion valve- expansion valve

In another way, TRV is a thermostatic expansion valve. Provides supply required amount coolant.

In simple air conditioners, its role is played by a capillary tube, without any adjustment, in inverter systems - by an electronic expansion valve.

2 way valve- a two-way valve, that is, a conventional valve, with two positions - open and closed

3 way valve- a three-way valve, in an air conditioner, this is a service port to which a hose of a manometric manometer is connected to measure pressure or charge.

4 way valve- four-way valve, provides refrigerant reversal for air conditioner operation in heating mode

Strainer- filter, in this diagram it is a filter-drier, as it is installed before the expansion valve (and after, since the system can operate in reverse mode and the refrigerant changes its direction of movement).

Its task is to prevent moisture from entering the thin channel of the expansion valve - as moisture will clog it, preventing the refrigerant from passing through.

Muffler- muffler

The arrows indicate the direction of freon movement along the contour:

• solid arrow - in cooling mode
• dotted arrow - in heating mode

Also, in more complex and advanced air conditioners, they install:

• Pressure Sensors
• liquid refrigerant separators
• bypass lines
• injection systems (injection) into the compressor
• oil separators

Scheme of a multi split system

Multi split system- this air conditioner has one outdoor unit and several indoor

In this case, a few more internal blocks are added, as well as:

distributor- a distributor that splits the refrigerant flow and directs it to several indoor units.

The scheme also contains elements that are used not only in multi systems:

receiver tank- receiver.

The receiver has several purposes - protection against compressor water hammer, freon drain during repairs, etc.

In this case, this is a linear receiver that prevents freon gas from entering the expansion valve

Scheme electrical connections outdoor unit split system:

Terminal - terminal block to connect the interconnect cable for connection with the indoor unit.

N- electrical neutral

2 - power supply to the compressor from the control board of the indoor unit

3 - supply power to the fan motor for operation at 1st speed

4 - supply power to the fan motor for 2nd speed operation

5 - power supply to the four-way valve actuator for switching to heating mode

Compressor

C- common - common output of the compressor windings

R- running - working winding of the compressor

S- starting - phase-shifting winding of the compressor motor, starting

Internal overload protector - internal protection overload

Compressor Capacitor- an electric capacitor, in this case a working one (there are also starting ones, currently they are not used in air conditioners)

fan motor- engine, fan motor

thermal protector- protection against overheating, usually placed directly on the motor windings and breaks the circuit when the temperature is exceeded.

Fan Motor Capacitor- fan motor run capacitor

SV- solenoid valve - solenoid valve, which actuates the four-way valve mechanism.

Scheme of the indoor unit of the air conditioner

Terminal block

On the terminal block, in addition to interconnections, there are also clamps for connecting power (power can be supplied and vice versa - to the external unit)

L, N- electric line and neutral of single-phase supply

Filter Board- filter board, reduces the level of interference in the power supply

Control Board- control board - controls all devices, receives data from all sensors, performs thermoregulation, displays information for the user on the display, performs self-diagnosis.

main relay- the main relay is a power relay that supplies voltage to the compressor.

display board - the display module can be a line of LEDs that show the presence of power, the selected mode, an error code, or a display that also displays the temperature.

Thermistor- thermistor, thermistor, temperature sensor

Room temp. - room temperature sensor

pipe temp. - heat exchanger tube temperature sensor, evaporator

Temperature sensors can also be located in:

• remote control - to maintain the temperature at the point where the remote control is located (for example, the "I Feel" mode).
• at the inlet, outlet and midpoint of the evaporator

step motor- stepper motor,

It is used to open louvre grilles, curtains covering the fan