If you need to cool two rooms, but there is only one place for an external unit, the optimal engineering solution will be a split system for 2 rooms - the equipment is especially relevant for new high-rise buildings, where parts of the facade, decorated with special baskets, are allocated for air conditioners.
What is the principle of operation of a “double” split, what are the advantages and disadvantages of the scheme, as well as how much does such a system cost? We’ll look at it in the article. In addition, we outlined the main parameters for choosing an air conditioner and described the specifics of its installation and maintenance.
Relevance of a “double” split system
In the private sector, there are usually no problems with installing several devices for different rooms. But if the owner does not want to spoil the facade with several bulky boxes, it also makes sense to consider a multi-split.
Business-class high-rise buildings are equipped with centralized systems, so the issue of air conditioning for an individual apartment is removed. In other cases, the installation of climate control equipment must comply with certain rules.
The dimensions of installed suspended units, for example, duct or cassette systems, are limited by the height of the ceilings. A quota has also been set for the total energy consumption in the apartment, which regulates the power of the supplied electricity. But most of all the rules concern external blocks.
In Europe, external blocks have long been mounted on roofs or placed on the inner side of the yard, which preserves the aesthetics of the facades
The installation of climate control equipment on the façade and outside of some buildings is prohibited by law or individual operating rules. But residents are offered designated places for such purposes on the balcony, roof, technical floor, and in special niches.
For small venues, square meters are not enough. One apartment is usually allocated only one space measuring about 60 cm by 1.5 m. The most expedient solution in this case would be to install a simplified multi-split system.
Ways to cool an apartment with air conditioning in one room
If an air conditioner is already installed in one of the rooms, but there is a need to lower the air temperature in others, then you can use one method - maximum cooling of one room. The air conditioner, designed for the area of a particular room, needs to be turned on to the minimum temperature, then go out and close the door. When the split system stops (which means that the thermostat has determined that the indicators have dropped to the set values), all that remains is to open the doors to the adjacent room - the cold air will partially escape and cool the second room. This is not an ideal method, since it will be cold in the first room, but this can be done, for example, if the air conditioner is in a bedroom in which no one is currently in, but there is a need to slightly cool the room from which the door to the cooled room opens.
There is another way - to create a directed air flow using a fan installed in the refrigerated room. But there will be similar problems: uneven cooling, overloading of the air conditioner, which is not designed for a large area. Additionally, there is another significant disadvantage - excess noise.
Operating principle of the equipment
What is the difference between such a split system when compared to a conventional air conditioner? The peculiarity is the triple division of the freon circuit.
The first part is located in the external block and consists of a compressor, flow dividers, and a condenser heat exchanger. The latter has 2 sections.
The compressor is forced to work constantly, even if one external unit is turned on, so more reliable elements with a resource reserve (+) are installed in such systems
The remaining two parts are located in indoor units and consist of evaporators and capillary tubes. All participants in the scheme are connected to each other by freon lines.
The operation of this scheme is based on the property of liquids that can absorb heat during evaporation, but, on the contrary, release it during condensation. The agent in refrigeration systems is freon, which circulates in the circuit.
Heat is absorbed by the indoor units and sent to the outdoor unit due to the thermodynamics of the agent's transition from liquid to gas and back.
Hot freon leaves the compressor under pressure and runs into the separator, where it splits into two to cool two rooms. Once in the evaporator, freon will have to transition to the gas state. Why does it take heat from room air, which is pumped by a fan.
Next, the freon is sent to the condenser heat exchanger (also 2 sections), where it is cooled to a liquid state.
In this way, the process of cooling the premises occurs. But the equipment can also work for heating. In this case, the direction of movement of freon changes.
Indoor unit location for cooling multiple rooms
In an effort to save money or if it is impossible to install several external units, some try to position one powerful air conditioner so that it immediately cools 2 or 3 rooms. There are several common options here:
- placing the air conditioner in the corridor, provided that it has access to all rooms where cooling is required;
Often the air conditioner is placed in the corridor so that it cools several rooms at once - placing the device opposite the door in adjacent rooms so that the air flow from one room immediately enters the other.
Some install an air conditioner opposite the door to adjacent rooms so that one device cools several rooms at once
Such an arrangement is possible, but you should understand that it is simply not possible to achieve complete air cooling in several rooms at once. It's all about poor air exchange - even through an open door, no more than 10-15% of the cold will escape into another room, which makes it impossible to create a uniform temperature in the apartment. In addition, such an arrangement of the air conditioner entails a number of inconveniences:
- When installing in one room a device with a cooling capacity designed for the entire area of the apartment or several rooms, a too sharp temperature difference will form - in the room where the air conditioner is located it will be very cold, since its area is smaller than the potential of the equipment.
- Air conditioners have a thermostat that stops the cooling process when the temperature specified by the user is reached. Thus, a powerful device will quickly cool the room and stop, preventing the temperature in adjacent rooms from being fully reduced.
Features of the functioning of air conditioners
It is technically possible to connect up to 7 internal boxes to one outer box. There are no clear connections between the power of the outdoor unit and the number of indoor units. One external person can work in a company with either two or three internal ones.
When calculating the circuit, we proceed from the total power of all indoor units, which must fit into the range of min and max values of the outdoor cooling capacity (+)
Conventional multi-splits differ from expensive and advanced multi-zone installations by the inability of indoor units to operate in a heat-cold pair.
They can function only in one climate direction - either all for cold, or all for heat. If you turn on the units in opposite modes, the equipment will not start.
But you can set different temperatures on each device. But you need to stay within one mode - either cooling or heating.
Varieties
Modern multi-zone air conditioning systems (multi-split systems) are a set of equipment with one module for installation on the facade and two (or more) for installation in rooms, each of which is installed in a separate room. Air conditioning occurs through the operation of an inverter system, which is the most innovative. The devices use the latest developments in the field of climate control.
Equipment sets traditionally consist of a number of components.
- External module. Mounted outside on one of the walls of the building.
- Indoor units (2 pieces or more) for placement in rooms inside the house.
- A set of communications for combining and operating elements of climate control equipment with each other.
- Control panels, one of which becomes the main one.
In this case, you can buy a ready-made kit from one manufacturer, or you can assemble it yourself from the necessary elements. Pre-assembled multi-split systems include several types of indoor units: wall-mounted, console, cassette and floor-ceiling. For apartments, wall-mounted or floor-ceiling indoor units are often purchased.
There are also stationary multi-split systems with an outdoor unit equipped with two compressors. Such equipment can operate by simultaneously heating the air in one of the rooms and cooling it in the other.
Selecting an installation based on characteristics
There is an opinion that a double split system should cost less than two separate appliances, but this is not true. Compared to the total price of two installations, one double installation will be 15-30% more expensive, even with the same power. The reason is the inverter operating principle.
Inverter models use advanced technologies plus all sorts of upgrades that cannot be found in conventional devices, which increases the cost of the system as a whole (+)
Non-inverter air conditioners are cheaper and can be equipped with a winter kit. But there is little such equipment in the product range of manufacturers due to low demand.
Three types of indoor units
Internal modules of cassette, channel or wall type can be connected to the external unit. Let's consider when and in what rooms they are used.
The cassette unit is not suitable for rooms with low ceilings and/or small areas. These models are designed for large commercial premises - offices, restaurants, shops, cinemas.
To install a cassette unit, you need 25-40 cm of inter-ceiling space, and laying all communications requires high labor costs and sufficient qualifications of performers
Channel wiring also involves reducing the height of the rooms. This option is the most aesthetic, albeit expensive.
It would be appropriate in a country cottage, but not for two rooms, but for several rooms. You can make a common wiring with one or two external units.
The duct system is ideal if there are increased requirements for the design of the premises and there are no problems with low ceiling heights. Only decorative grilles remain in the visible part
Wall blocks are the optimal solution for an ordinary apartment or house with standard ceilings. They are easy to install and do not require large premises.
Technical parameters of devices
External units in double split systems are more reliable and the total length of their routes is longer when compared with conventional ones.
Indoor units are selected according to:
- power;
- range of outdoor temperatures;
- set of functions;
- length of communications;
- appearance.
The main functional parameter is the range of outdoor temperatures. It is important that the equipment operates in conditions that are below the maximum permissible. The efficiency of the equipment depends on the atmospheric load.
It is also important to consider the following three parameters:
- Corrections for additional heat inflows . Often, these coefficients require different indoor units for different rooms.
- Outer box power , which should be equal to the total cooling capacity of the indoor units plus correction factors. The outdoor unit may have 3 or 4 ports for connecting freon pipes, but only 2 are needed.
- Measurements of the maximum length of all freon pipes to the indoor units: each individually and the total number.
The disadvantages of the design include the need to install internal devices close to each other - next door. The distance depends on the length of the route in the selected model.
When calculating the power of one indoor unit, we proceed as with a conventional air conditioner: we start from the area of the room and the height of the ceilings. Then we sum these indicators to get the power of the outdoor unit (+)
There is also a simplified formula: for 10 m2 you need about 1000 W of power. This calculation works for rooms with good thermal insulation. If the light enters the room from the south or southwest side, add another 25% to the indicators.
Detailed instructions for calculating split power are presented in this article.
Manufacturers and models
Fujitsu , Mitsubishi , Toshiba are traditionally considered the most reliable manufacturers . They are also the most expensive brands.
The average price category is the Chinese General Climate and the Japanese Daikin . Budget series - Chinese Hisense , English-Chinese Dantex .
Of the 2-room models, you can consider the following:
- Mitsubishi Electric MSZ-HJ25VA-ER1×2/MXZ-2HJ40VA-ER1 : for 50 m2 with deodorizing and anti-allergenic filter, low noise level of 20 dB, night mode.
- General Climate GC-M2E18HRN1 : for 53 m2, there is a mode of ventilation, self-diagnosis, dehumidification, but no fine filters.
- Electrolux EACS/I-07HP+EACO/I-14 FMI-2 : for 40 m2, economical energy consumption, heating operates at temperatures down to –15 degrees.
- Fujitsu Inverter AOYG14LAC2 : an external unit that can be equipped with budget internal ASYG07LMCA (15 m2) or large-area ASYG07LUCA (20 m2) and ASYG09LUCA (25 m2).
- Hisense AMW2-20U4SNC1/AMS-09UR4SVEDB6x2 : for 50 m2, two-way condensate drain connection is provided.
- Dantex RK-2M24SEGE : for 70 m2, there is a system against ice formation, but it works for heating at temperatures down to –7°C.
The product lines include fixed and dial systems. The first ones imply a complete set from the manufacturer. In the second case, you can select the blocks yourself.
Fixed ones are convenient if you intend to service premises of the same area (minor deviations are acceptable). Typesets are relevant in the opposite cases with rooms of different sizes
Power selection
When calculating the performance of a multi-split system, several factors must be taken into account:
- Rooms in which a multi-split system will be installed: area, purpose of the room, heating system.
- Power of indoor units. Their total performance must not be allowed to exceed the power of the external module. There are online services to calculate this indicator.
- Pipeline length. The higher this indicator, the more powerful the blocks in remote rooms should be.
Among the inexpensive multi-split air conditioners are the following manufacturers: LG, General Climate, Midea. Sets of multi-split systems for 4 rooms are already distributed according to power. One outdoor module can cool eight rooms with a total area of up to 200 square meters. m.
When choosing a multi-split system, you need to take into account the placement of the modules: on the floor, wall or ceiling.
Specifics of installation and operation
If you compare the cost of installing two separate air conditioners and a double split system, the amount will be approximately the same. The reason is the similar length of the tracks. The price of installation directly depends on the length of interblock connections, cables, freon tubes.
During installation, it is worth considering that the freon bypass control system requires accurate accounting of the amount of substance for each of the indoor units
When the installation of an air conditioner is carried out under general repair conditions, it is advisable to split the installation of the split system into 2 stages.
First, groove the walls, install inter-block communications, secure the outdoor unit, and work on the internal equipment after the finishing of the premises.
If installation is carried out after repair, freon pipes are sewn into special channels. They are not hidden in the walls, but this makes it easier to replace if the need arises in the event of a breakdown or the desire to install more powerful equipment
It is better to place the outdoor unit on the facade under the window so that the technician has access to it during maintenance.
Operational features of the split system:
- The outdoor unit operates at full power even if the air conditioner is turned on in only one room. This increases the energy consumption per device.
- Two devices cannot operate simultaneously for heat and cold. But if the system supports ventilation mode, you can turn on heating in one room and set ventilation in another.
- If one outdoor unit breaks down, two rooms will be left without air conditioning.
Indoor units, regardless of their number, require periodic sanitary maintenance.
Mold on the evaporator fins and fan turbines reduces the performance of the device by half and contributes to the appearance of an unpleasant odor.
How to choose the right place to place the outdoor unit
Few places have a technical balcony. The most convenient place to place the external module is next to the fire escape. Next comes a place next to the balcony, then under the window.
In these places they can be maintained without the involvement of industrial climbers, which significantly reduces operating costs.
Results
Are there air conditioners for 2 rooms? The modern market offers a variety of devices for every taste and budget, including those for cooling or heating several rooms at the same time. If you follow the rules, you can install from two to eight air conditioners in an apartment, even if you live in an ordinary multi-story building.
For these purposes, you can use multi-split air conditioners. This is a modern and effective solution for apartments and country houses, although in the latter the problem is not so acute. With proper installation and regular maintenance, such air conditioners will serve you well for many years.
We are sure that among our readers there are owners of multi-split systems and professional installers. Share your experiences and recommendations in the comments below. Tell us what difficulties you encountered during operation or installation, what you like or don’t like about multi-split systems.
Good luck!
