What is a split system: device and principle of operation, how to choose and maintain

СA cooker system is an air conditioner that is structurally divided into two blocks, external and internal. “Split” from English is translated as “separate”. The first unit is mounted outdoors, and the second indoors, and they are connected to each other by heat-insulated pipes.

The system can be installed in an apartment, house, hotel rooms, office, country house and other premises. Can be used in greenhouses and indoor gardens to create an optimal microclimate.

Below we will consider how a split system differs from a simple air conditioner, what types there are. We will separately consider the device, principles of operation, functions and capabilities, the types of refrigerant used and filters. Let’s highlight the TOP-5 most popular models that differ in price and quality.

What is the difference between a split system and an air conditioner

There are no differences between these devices – this is the same device. In fact, a split system is one of the types of air conditioning, consisting of one, two or more units.

Single air conditioners include ordinary air conditioners that are installed on the window, in cars or are mobile. Split systems just belong to the last category.

The term itself appeared from English and means “split system” or “separate system”, consisting of an external and internal unit.

In a conventional air conditioner (mobile or window), the main parts are in one housing. This results in high noise levels (up to 50 decibels).

Falling asleep while using such a device is extremely difficult, which is why it was decided to divide it into two sets. The first (noisy) is installed on the street, and the second (quiet) – directly in the room.

Many people think that the outer part is needed to draw in air. But it’s not. In practice, the intake of the air flow is taken over by the indoor unit located inside the room and does not cause problems for users in terms of noise.

But there are also models in which air is taken from the outside, after which it is cooled, and only then it is fed into the room.

In general, there are several differences between a split system and an air conditioner:

1. Design. Mobile and window devices are large, and the indoor units have a stylish appearance and can be mounted in different places.
2. Heating. Modern split systems are able not only to cool, but also to heat the air.
3. Installation. Separate systems are more difficult to mount, but they have more options. Air conditioners are easier to install – just plug them into a power outlet, remove the tube with condensate and use it.

Differences between a split system and a conventional air conditioner.

Advantages and disadvantages

Pros:

• automatic maintenance of the set temperature in the room;
• creation of an optimal microclimate;
• quiet work;
• a wide range of devices;
• consumption of a relatively small amount of energy;
• convenient control system;
• possibility of application even at “minus” temperatures.

Cons

• higher price compared to simple air conditioners;
• fear of power surges (installation of a stabilizer is recommended);
• deterioration in the appearance of the building due to the bulky external unit;
• the complexity of maintenance, which must be done periodically without fail.

Types

Split air conditioning systems have one external and from one to a dozen indoor units connected to the main one (which is located on the street).

By type, such systems are divided into several types: channel, wall, cassette, floor-ceiling, column.

Duct

Designed to serve large areas, which are often divided into several separate rooms.

Structurally, they consist of two blocks: external and internal. The difference is that the internal nodes are located above the suspended ceilings and are hidden.

Some models are installed in closets. In this case, the air that departs from the indoor unit is directed into the room.

Wall mounted

The most popular split systems designed for use in shops, apartments, offices and country houses.

Such devices are recommended for use in rooms with an area of ​​​​10 to 100 square meters. The outer part, as a rule, is fixed outdoors, and the inner part indoors.

In fact, it is these devices that we buy ourselves for installation at home or in office premises.

Cassette with air supply in four directions

The main difference is the indoor unit, which is mounted under the ceiling. Most often mounted in business centers, large offices, apartments under construction, office buildings and cafeterias.   

Floor-ceiling with horizontal or vertical placement

Universal devices that are most often placed under the ceiling or near the floor.

The location depends on the configuration of the room, and the installation location is determined taking into account the features of the interior.

The installation of such models is relevant in the case when the use of other split systems is impossible.

Sometimes such devices are mounted due to the high air flow rate, which is important in large premises – shopping centers, offices, conference rooms, etc.

Columned

Separate systems with an internal column block. Such devices are often referred to as cabinet air conditioners due to their appearance.

They are not attached to the floor, but placed in the right place, which simplifies the installation issue. It remains only to solve the issue of connecting and supplying freon.

In some cases, they can be attached to the wall. They are installed in large rooms, have a power of 8 to 20 kW.

The block type is selected taking into account the tasks. For example, for a house, apartment, hotel room and cottage, channel or wall-mounted ones are suitable.

For large rooms, it is better to use the last three types.

Устройство

When considering a split air conditioning system, it is necessary to study the design features of each of the blocks.

The internal component includes:

1. The evaporator is a radiator divided into many plates. It is used to transfer cold from freon located inside the radiator assembly.
2. Fan – a shaft with blades, used to drive the air flow through the radiator (evaporator).
3. Filters. Conventionally, there are several types: fine / coarse cleaning, plasma. located under the lid. Coarse filter elements need periodic cleaning, while thin ones are mounted on coarse filters and also need cleaning.
4. Tray for drainage. Collects water that appears during the operation of the air conditioner. In the next step, the liquid is drained through the drain tube
5. Electronic control board. It integrates all electrical equipment, sensors and other elements. Takes over the functions of managing all components of the split system.
6. Frame. It contains all the components of the block, differing mainly only in design.

Modern indoor units have many built-in features. The main ones include temperature control, a timer, a display with detailed information about the climate, air purification from dust / smoke, air ionization, etc.

As for the outdoor unit, it is arranged differently:

1. Capacitor – radiator made of copper or aluminum. Designed for heat exchange between the environment and freon. During the operation of the cooling system, freon condenses and passes from a gaseous to a liquid state.
2. Compressor – compresses the working gas and ensures its movement along the contour of the device.
3. Fan – creates an air flow that passes through the condenser. In expensive devices, a speed control function is provided.
4. Freon filter – located under the compressor unit, protects against the penetration of copper chips or other debris.
5. 4-way valve – works for heating and cooling, is used to change the flow of freon inside the system when the mode changes.
6. Electrical equipment. It is used to control the split system. In inverter type devices, the board is located in the external unit.
7. Case – unites all elements of the device, provides protection from negative factors.

The outdoor unit is placed on the facade, on the roof, balcony / loggia, in the corridor, on the stairs or in the metro lobby.

Installing a compressor in an outdoor unit allows you to reduce the noise of a classic split system to 24-26 decibels.

The principle of operation of the split system

Knowing the device of the air conditioning system, the question arises about the principle of its operation.

The operation of the system is based on a simple cycle, which involves the intake of indoor temperature and its output in the outdoor unit. In the case of heating, this process takes place according to the reverse algorithm. Let’s consider each of the cycles in more detail.

Охлаждение

Freon acts as the main element, which is compressed in the compressor and heated, and in the next step it transfers heat to the external unit.

As a result, the temperature of the gas decreases and condensation occurs.

Freon in the form of a liquid enters the throttle and goes to the inside of the system, and there it evaporates.

As a result of lowering the temperature, heat is taken from the warm room with further supply to the compressor, after which the process is repeated in a circle.

Regulation implies a change in the volume of freon and, accordingly, a change in the rate of heat exchange in the right direction. A throttle valve is used for regulation.

Heat

In this case, the cycle discussed above is applied, but in the opposite direction. First, the gas is compressed in the outer part, followed by transmission to the indoor unit. This is where heat transfer and cooling take place.

Most often, the function is used as an addition. With frequent use of a split system for heating, it is better to buy devices with a heating element, but in this case, electricity consumption increases.

Drying

Many separate systems are capable of removing moisture from the air. If desired, only this mode can be used without the use of cooling / heating. If you select any of these options, drying is added additionally.

Circulation and cleaning

When this option is selected, the air flow is mixed and cleaned using filter elements.

Filters are either coarse or fine. The first remove large, and the second – small debris. Activated carbon filters are used to remove foreign odors.

humidification

The air passes through the water, which allows you to increase the level of humidity in the room. This option is found in modern split systems and greatly affects the cost of the device.  

When used at home, it is easier to buy a regular humidifier.

Ionization

An additional option that implies the saturation of the air flow with charged ions.

“Negative” elements give a feeling of freshness, as after a thunderstorm, contribute to the destruction of bacteria and add health benefits.

But keep in mind that this function is not suitable for everyone, and some simply do not like the specific smell of the air.

Fresh air supply

The essence of the function is not only cooling / heating, but also saturating the air with a fresh stream from the street.

The downside is that the presence of such an option leads to the complexity of the design and installation. That is why this option is found in mid-range or high-end devices.

Supported features and functionality

Modern split air conditioning systems provide many useful features that affect the features of the device and its cost.

When choosing, pay attention to the features that you really need.

Unusual design

It implies a non-standard design of the block indoors. Any design that differs from the classic rectangular white rectangle falls into this category.

Devices with this feature can be made in different colors with original design elements.

Such devices can be used as a design element that allows you to “refresh” the design of any room.

Night mode

A special option designed to reduce electricity consumption and create optimal conditions for relaxation. When this mode is enabled, the fan starts to operate at minimum power to reduce noise, and the temperature changes smoothly.

Some models have a timer that allows the split system to turn off after 7-8 hours.

I feel

The option implies the presence of a remote control with a thermometer and a sensor built into it.

In such a device, as a rule, a separate key is provided, pressing which allows you to measure the air temperature around the remote control.

This feature allows you to more accurately adjust the microclimate with a focus on the user, and not on the installation site of the indoor unit.

Standby heating

Provided in split systems with the possibility of heating. Suitable for summer cottages, houses and other objects that can remain without heating for a long time in winter.

The task is to maintain the temperature at the level of 8-10 degrees Celsius even in frost.

This level is enough to protect walls from freezing and communications from damage. This consumes a minimum amount of electricity.

WiFi module connection

It implies the connection to the split-system Wi-Fi module, which expands the functionality of the device.

For example, you can connect to it using a smartphone to remotely control the main functions, obtain statistics, carry out diagnostics, remove breakdowns and solve other problems.

The detailed set of functions provided by the WiFi module needs to be specified individually.

In some modern models, the WiFi module is built-in, but in this case the cost of the device is higher.

It is better to take a device with the ability to connect in order to decide in the future on the relevance of the option (it may not be needed).

Vertical blind drive

It provides for the presence of its own drive for blinds at the output of the split system.

Note that in most devices, the sashes can only be adjusted horizontally, but in more modern models there is a blinds drive that works vertically.

In this case, you can change the direction of the air from left to right and vice versa. This feature expands the capabilities of the device.

Smartphone control

Allows you to remotely control the split air conditioning system from a smartphone or other device through a special application.

This method is more convenient than working with a conventional remote control, because you can use additional functions, monitor the parameters of the device online, connect to the global network and manage the performance of the split system.

You can use Wi-Fi or Bluetooth to connect to your phone.

Presence sensor

It implies the presence of a sensor that controls the movement of people around the room. Having this information, the split system itself regulates the direction of the flow so that it does not fall on people.

As a result, it is possible to avoid drafts and, as a result, colds.

If there is no one in the room at all, the air conditioner switches to economy mode with reduced power and maintaining the optimum temperature.

Depending on the configuration of split systems, it can even be turned off for even greater savings.

Screen on indoor unit

It is a small display that displays various information on the operation of the split system: temperature, operating mode, fan speed, mode, timer data, errors, and more. This option makes management more convenient.

Air pollution sensor

Detects the content of dust, smoke and other contaminants in the air. The scope of the sensor can be different: starting air filtration, turning off / on ventilation, etc.

Drainage pump

Provides an additional device necessary for the removal of condensate over long distances, including in the vertical direction. Suitable for offices where the indoor unit is inaccessible and hidden under the ceiling.

Self cleaning

It involves blowing air through the split system to dry the internal elements and protect against the appearance of bacteria. This option does not include filter cleaning, which must be maintained manually.

I would also like to say about the TURBO function that allows you to quickly cool or heat the room.

What is a multi-split system

This category includes split air conditioning systems, which are equipped with two or more indoor units.

The main feature is the presence of one external (main) element and a group of blocks connected to it, installed indoors.

Such options are used to create an optimal microclimate in large rooms, shops, office premises, shopping centers and other facilities.

Reducing the number of external blocks allows you to improve the design of the object and not clutter up its facade.

The peculiarity is that the external node can be combined with internal blocks of various types: cassette, ceiling and others.

Due to the design features, high demand and complex design, they have a higher price.

Multi-split systems are divided into two categories according to the number of compressors:

1. With one. In such devices, information is sent to the electronics of the outdoor unit via digital channels. After that, the data is processed with further determination of the optimal mode of operation. In addition, the functions of the electronic part include the control of the system of bypass channels.
2. With two or more. Such installations have two or three compressors, a condenser and other equipment in the external unit, as well as one unit. As a rule, indoor units differ little in design and signals from classic split systems. The electronics of the external unit receives signals from the internal ones, after which it regulates the principle of operation of the compressor, taking into account the received data. We note right away that multi-compressor installations can be with or without an inverter option.

inverter type

A feature of inverter systems is to keep the compressor in the on position, smoothly control the power and select the mode for a specific situation.

This reduces the weight of the split system, reduces noise and reduces electricity consumption.

The main disadvantage of inverters is the high price and excessive sensitivity to power.

For such split systems, the use of a voltage stabilizer is recommended.

The working principle of the inverter system is as follows:

1. Switching on the split system.
2. Reaching the desired temperature.
3. Continued operation at reduced power to maintain the desired temperature.

More budget models turn off when the set air temperature is reached, but more expensive inverter-type devices continue to work with minimal power consumption.

The advantages of inverter split systems include:

• ease of use;
• almost silent mode of operation;
• maintaining the desired temperature 24/7;
• high accuracy;
• work on heating at a temperature from -10 to -25 degrees Celsius;
• increased resource;
• low power consumption.

Cons:

• higher price;
• dependence of the control board on voltage drops;
• higher cost of repairs.

It would seem that in inverter split systems, since they are constantly working, electricity should not be saved.

But in fact, if we take, for example, a conventional air conditioner, then after the air in the room cools down, in order for it to catch up with the set temperature parameters in the room, it is necessary to work at increased capacities, while consuming quite a lot of electricity.

And inverters spend a minimum, only maintaining the already reached temperature.

The principle is somewhat similar to the work of multicookers, which spend less electricity in 1 hour of operation than, for example, an electric kettle turned on in 5 minutes.

Types of refrigerants used

Different types of refrigerants are used as coolers in split systems. Let’s briefly consider the features of the main options.

R410A

An azeotropic refrigerant containing elements with identical evaporation parameters. In the event of a leak, the characteristics of the refrigerant remain unchanged.

The features of the R410A include a higher pressure, which imposes more stringent requirements on the parameters of reliability and strength of the circuit.

As a result, the price of the device also increases. One reason is the high price of the refrigerant itself.

R32

An advanced refrigerant option that has three main advantages – isotropy, safety and efficiency.

Air conditioning systems with this refrigerant are more compact. In addition, the composition itself is not harmful to the environment, and if necessary, you can easily refuel the air conditioner.

Of the minuses – the high price, due to the cost of R32 and high design requirements.

R407C

It is an alternative to R22 (described below), does not harm the ozone layer, but has a higher price and operating pressure.

The composition includes polyester oil, which takes moisture during operation, and this, in turn, leads to a deterioration in the quality of work.

In addition, the filler is heterogeneous in composition, and its elements have different parameters in terms of volatility and boiling point.

As a result, even with minimal leakage, the properties of the refrigerant deteriorate, and the air conditioner has to be recharged.

R22

The oldest type of refrigerant, which has a low price and requires little pressure. As a result, the system is more reliable and the price is lower.

Due to the homogeneity, in the event of a leak, the system can be quickly supplemented with the same type of working composition.

But the refrigerant itself is dangerous for the ozone layer, which is why today it is almost never used in production.

Applied filters

In modern split air conditioning systems, different filter elements can be used.

The main ones are dust, which are mounted in almost all modern air conditioners.

But in more advanced models, more powerful filters are also provided.

Antifungal

A special filter that removes dangerous fungi from the air, such as mold. This option is provided in many individual devices, but in the air conditioner it is more efficient.

As a rule, antifungal filters are not always needed and often antibacterial elements can be dispensed with.

Plasma (electrostatic)

The action of the filter element is aimed at saturating oxygen with ions with a “minus” charge. As a result, the split air conditioning system plays the function of an ionizer.

Additionally, such filters are able to kill microorganisms, destroy harmful substances and trap dust and smoke.

In addition, such elements, under the action of air saturated with ions, themselves receive a charge and are attracted to the filter plates.

Deodorant

The filter element, the function of which is to combat odors at the molecular level, as well as to remove large particles from the air.

A classic representative of such products is an activated carbon filter.

Other sorbents can also be used, which require periodic replacement during operation. If the filter is not changed in time, it itself becomes a source of pollution.

antibacterial

Designed to purify the air from fungi, bacteria and other harmful substances.

The principle of operation may differ: UV radiation, the use of biologically active additives, etc.

But it is worth considering that not all such filters are able to cope with viruses. This point must be clarified separately when buying.

catechin

One of the subspecies of the antibacterial filter. The peculiarity is the use of catechin – a natural substance that disinfects the air, has a low price and high efficiency.

Such devices can also save in protection against viruses, therefore they are allocated to a separate group.

Comparative characteristics of popular models

To simplify the choice, we present a selection of split air conditioning systems and compare their characteristics.

Please note that this is not the best product, but taken as an example and a deeper understanding of the material. Although these are not the worst offers on the market and they can be considered for purchase.

Samsung AR09TQHQAURNER/AR09TQHQAURXER

Budget wall-mounted air conditioner with several modes of operation and three fan speeds. The movement of air along the vertical is carried out automatically, and in the horizontal plane it is regulated independently.

A high-density filter is used to purify the air, holding up to 90% of large particles and dust. There is a timer that can be programmed to turn on and off.

When there is a power outage in the house, an automatic restart is triggered. There are options for comfortable sleep and the presence of a heating function that operates at temperatures up to -15 degrees Celsius.

Energolux SAS12L2-A/SAU12L2-A

Split system with a modern European design and a convenient display that displays the necessary information: mode, temperature and more. A multi-stage air purification system is provided.

The kit comes with carbon and antibacterial filter elements. Additional features of the model are self-diagnosis, automatic mode selection, timer, silent operation, ionization and others.

GREEN GRI/GRO-24HH2

Split system from a well-known brand with a self-diagnostic function and the ability to automatically restart in the event of an accident or blackout.

The IFeel option is provided, which implies the presence of a temperature control sensor in the remote control, rest mode.

There is also an “Anti-ice” option, which protects the device from icing in winter and increases work efficiency.

If you need faster cooling, you can turn on the turbo mode.

Oasis ET-12

Wall mounted split system with inverter compressor providing efficient cooling/heating with minimal noise.

The presence of an automatic mode allows you to save time on creating the optimal microclimate in the room.

A special filter is also built into the device, which cleans the air stream from dust. Of the additional options, it is worth highlighting a turbocharged mode, a timer for programming, a self-diagnosis option and an automatic restart.

General Climate GC/GU-A24HR

Classic wall split system from a Chinese brand. The internal block is completed with the informative display on which all necessary information is displayed.

Inside there is a filter element that cleans the passing air stream from impurities.

Of the useful options – turbo mode, self-diagnosis, automatic defrosting of the external unit.

Comes with two replaceable charcoal filters.

Features of use at high outdoor temperatures

A separate issue concerns the use of devices at high temperatures outside. Here, to ensure the functioning of the split system, there are higher requirements for pressure, which increases significantly.

In this case, the maximum pressure / temperature parameters depend on the type of refrigerant.

For example, for the most popular R410A, the critical parameter is +72 degrees Celsius, so the temperature limit for the operation of a split system is limited to 50 degrees.

In the case of R22, the critical / maximum parameter is 96 / 70 degrees Celsius, respectively. Achieving the above indicators is quite realistic if the outdoor unit is installed incorrectly.

For example, it can be placed on the roof in the place of a “mirror”, namely the concentration of sunlight.

With an increase in the temperature outside, the pressure difference at the inlet-outlet increases. As a result, more gas passes through the capillary tube. As a result, the compressor is loaded more and the energy consumption of the equipment increases.

Often under such circumstances, overheating and tripping from protection can occur. This is quite real, because split systems are adjusted to temperatures up to 40 degrees Celsius.

Sometimes when working in conditions of elevated temperatures, non-standard modes may be used.

For example, if you reduce the capacity of the tube, it will be easier for the compressor to create a large pressure difference at the inlet-outlet and it will be possible to reduce the amount of refrigerant in the system.

The downside is that during normal operation, the use of such a system is impossible, so the use of this option reduces the resource.

Does it need to be serviced?

During the operation of the split system, special attention should be paid to the indoor units. They must be maintained regardless of the type of filter element, the presence of a self-cleaning option and other useful features.

Due to the accumulation of condensate, mold appears on the fan turbine and evaporator already the next year from the date of purchase and installation.

Without regular maintenance, the efficiency of the device drops, unpleasant odors appear, and elements of the fungus scatter throughout the room.

For maintenance, the unit is completely disassembled with further cleaning and disinfection of internal elements. To perform such work, it is recommended to involve specialists.

Installing filters, as a rule, is aimed at attracting buyers, because often the effect of them is less than stated.

For example, catechin cleansers should be changed after a month, because then they are not effective. Moreover, without replacement, the smell of a swamp appears in the room.

At the same time, buyers are rarely informed about such features, because the main task of the consultant is to sell the product.

Split air conditioning systems are universal devices, without which it is difficult to imagine a modern apartment, private house or office today.

Due to the variety of options, you can quickly choose a model. But don’t go after “fashionable” features. Choose models that are suitable for area, reliability and basic operating modes.